From 49f474331e563a6ecf3b1e87ec27ec5482b3e4f1 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sun, 27 Dec 2009 11:51:52 +0100 Subject: perf events: Remove arg from perf sched hooks Since we only ever schedule the local cpu, there is no need to pass the cpu number to the perf sched hooks. This micro-optimizes things a bit. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 27 ++++++++++++++------------- kernel/sched.c | 6 +++--- 2 files changed, 17 insertions(+), 16 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 03cc061398d1..099bd662daa6 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1170,9 +1170,9 @@ static void perf_event_sync_stat(struct perf_event_context *ctx, * not restart the event. */ void perf_event_task_sched_out(struct task_struct *task, - struct task_struct *next, int cpu) + struct task_struct *next) { - struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = task->perf_event_ctxp; struct perf_event_context *next_ctx; struct perf_event_context *parent; @@ -1252,8 +1252,9 @@ static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx) static void __perf_event_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx, int cpu) + struct perf_cpu_context *cpuctx) { + int cpu = smp_processor_id(); struct perf_event *event; int can_add_hw = 1; @@ -1326,24 +1327,24 @@ __perf_event_sched_in(struct perf_event_context *ctx, * accessing the event control register. If a NMI hits, then it will * keep the event running. */ -void perf_event_task_sched_in(struct task_struct *task, int cpu) +void perf_event_task_sched_in(struct task_struct *task) { - struct perf_cpu_context *cpuctx = &per_cpu(perf_cpu_context, cpu); + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_event_context *ctx = task->perf_event_ctxp; if (likely(!ctx)) return; if (cpuctx->task_ctx == ctx) return; - __perf_event_sched_in(ctx, cpuctx, cpu); + __perf_event_sched_in(ctx, cpuctx); cpuctx->task_ctx = ctx; } -static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx, int cpu) +static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx) { struct perf_event_context *ctx = &cpuctx->ctx; - __perf_event_sched_in(ctx, cpuctx, cpu); + __perf_event_sched_in(ctx, cpuctx); } #define MAX_INTERRUPTS (~0ULL) @@ -1461,7 +1462,7 @@ static void rotate_ctx(struct perf_event_context *ctx) raw_spin_unlock(&ctx->lock); } -void perf_event_task_tick(struct task_struct *curr, int cpu) +void perf_event_task_tick(struct task_struct *curr) { struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; @@ -1469,7 +1470,7 @@ void perf_event_task_tick(struct task_struct *curr, int cpu) if (!atomic_read(&nr_events)) return; - cpuctx = &per_cpu(perf_cpu_context, cpu); + cpuctx = &__get_cpu_var(perf_cpu_context); ctx = curr->perf_event_ctxp; perf_ctx_adjust_freq(&cpuctx->ctx); @@ -1484,9 +1485,9 @@ void perf_event_task_tick(struct task_struct *curr, int cpu) if (ctx) rotate_ctx(ctx); - perf_event_cpu_sched_in(cpuctx, cpu); + perf_event_cpu_sched_in(cpuctx); if (ctx) - perf_event_task_sched_in(curr, cpu); + perf_event_task_sched_in(curr); } /* @@ -1527,7 +1528,7 @@ static void perf_event_enable_on_exec(struct task_struct *task) raw_spin_unlock(&ctx->lock); - perf_event_task_sched_in(task, smp_processor_id()); + perf_event_task_sched_in(task); out: local_irq_restore(flags); } diff --git a/kernel/sched.c b/kernel/sched.c index 18cceeecce35..d6527ac0f6e7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2752,7 +2752,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev) */ prev_state = prev->state; finish_arch_switch(prev); - perf_event_task_sched_in(current, cpu_of(rq)); + perf_event_task_sched_in(current); finish_lock_switch(rq, prev); fire_sched_in_preempt_notifiers(current); @@ -5266,7 +5266,7 @@ void scheduler_tick(void) curr->sched_class->task_tick(rq, curr, 0); raw_spin_unlock(&rq->lock); - perf_event_task_tick(curr, cpu); + perf_event_task_tick(curr); #ifdef CONFIG_SMP rq->idle_at_tick = idle_cpu(cpu); @@ -5480,7 +5480,7 @@ need_resched_nonpreemptible: if (likely(prev != next)) { sched_info_switch(prev, next); - perf_event_task_sched_out(prev, next, cpu); + perf_event_task_sched_out(prev, next); rq->nr_switches++; rq->curr = next; -- cgit v1.2.3 From 07b139c8c81b97bbe55c68daf0cbeca8b1c609ca Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 21 Dec 2009 14:27:35 +0800 Subject: perf events: Remove CONFIG_EVENT_PROFILE Quoted from Ingo: | This reminds me - i think we should eliminate CONFIG_EVENT_PROFILE - | it's an unnecessary Kconfig complication. If both PERF_EVENTS and | EVENT_TRACING is enabled we should expose generic tracepoints. | | Nor is it limited to event 'profiling', so it has become a misnomer as | well. Signed-off-by: Li Zefan Cc: Frederic Weisbecker Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Paul Mackerras LKML-Reference: <4B2F1557.2050705@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- include/linux/ftrace_event.h | 2 +- include/linux/perf_event.h | 2 +- include/linux/syscalls.h | 4 ++-- include/trace/ftrace.h | 12 ++++++------ include/trace/syscall.h | 4 ++-- init/Kconfig | 13 ------------- kernel/perf_event.c | 4 ++-- kernel/trace/Makefile | 4 +++- kernel/trace/trace_events_filter.c | 4 ++-- kernel/trace/trace_kprobe.c | 14 +++++++------- kernel/trace/trace_syscalls.c | 5 ++--- 11 files changed, 28 insertions(+), 40 deletions(-) (limited to 'kernel') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 2233c98d80df..0a09e758c7d3 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -188,7 +188,7 @@ do { \ __trace_printk(ip, fmt, ##args); \ } while (0) -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS struct perf_event; extern int ftrace_profile_enable(int event_id); extern void ftrace_profile_disable(int event_id); diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index a494e7501292..9a1d276db754 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -658,7 +658,7 @@ struct perf_event { perf_overflow_handler_t overflow_handler; -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_EVENT_TRACING struct event_filter *filter; #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 65793e90d6f6..b7c7fcf7790b 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -99,7 +99,7 @@ struct perf_event_attr; #define __SC_TEST5(t5, a5, ...) __SC_TEST(t5); __SC_TEST4(__VA_ARGS__) #define __SC_TEST6(t6, a6, ...) __SC_TEST(t6); __SC_TEST5(__VA_ARGS__) -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS #define TRACE_SYS_ENTER_PROFILE_INIT(sname) \ .profile_enable = prof_sysenter_enable, \ @@ -113,7 +113,7 @@ struct perf_event_attr; #define TRACE_SYS_ENTER_PROFILE_INIT(sname) #define TRACE_SYS_EXIT_PROFILE(sname) #define TRACE_SYS_EXIT_PROFILE_INIT(sname) -#endif +#endif /* CONFIG_PERF_EVENTS */ #ifdef CONFIG_FTRACE_SYSCALLS #define __SC_STR_ADECL1(t, a) #a diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 73523151a731..2fdd36df41f6 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -498,7 +498,7 @@ static inline int ftrace_get_offsets_##call( \ #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS /* * Generate the functions needed for tracepoint perf_event support. @@ -541,7 +541,7 @@ static void ftrace_profile_disable_##name(struct ftrace_event_call *unused)\ #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) -#endif +#endif /* CONFIG_PERF_EVENTS */ /* * Stage 4 of the trace events. @@ -626,7 +626,7 @@ static void ftrace_profile_disable_##name(struct ftrace_event_call *unused)\ * */ -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS #define _TRACE_PROFILE_INIT(call) \ .profile_enable = ftrace_profile_enable_##call, \ @@ -634,7 +634,7 @@ static void ftrace_profile_disable_##name(struct ftrace_event_call *unused)\ #else #define _TRACE_PROFILE_INIT(call) -#endif +#endif /* CONFIG_PERF_EVENTS */ #undef __entry #define __entry entry @@ -834,7 +834,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ * } */ -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS #undef __perf_addr #define __perf_addr(a) __addr = (a) @@ -926,7 +926,7 @@ static void ftrace_profile_##call(proto) \ DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args)) #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) -#endif /* CONFIG_EVENT_PROFILE */ +#endif /* CONFIG_PERF_EVENTS */ #undef _TRACE_PROFILE_INIT diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 961fda3556bb..3d463dcef298 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -49,12 +49,12 @@ ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s); enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags); enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags); #endif -#ifdef CONFIG_EVENT_PROFILE + +#ifdef CONFIG_PERF_EVENTS int prof_sysenter_enable(struct ftrace_event_call *call); void prof_sysenter_disable(struct ftrace_event_call *call); int prof_sysexit_enable(struct ftrace_event_call *call); void prof_sysexit_disable(struct ftrace_event_call *call); - #endif #endif /* _TRACE_SYSCALL_H */ diff --git a/init/Kconfig b/init/Kconfig index a23da9f01803..06dab27c18d9 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -966,19 +966,6 @@ config PERF_EVENTS Say Y if unsure. -config EVENT_PROFILE - bool "Tracepoint profiling sources" - depends on PERF_EVENTS && EVENT_TRACING - default y - help - Allow the use of tracepoints as software performance events. - - When this is enabled, you can create perf events based on - tracepoints using PERF_TYPE_TRACEPOINT and the tracepoint ID - found in debugfs://tracing/events/*/*/id. (The -e/--events - option to the perf tool can parse and interpret symbolic - tracepoints, in the subsystem:tracepoint_name format.) - config PERF_COUNTERS bool "Kernel performance counters (old config option)" depends on HAVE_PERF_EVENTS diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 099bd662daa6..5b987b4a98a8 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4177,7 +4177,7 @@ static const struct pmu perf_ops_task_clock = { .read = task_clock_perf_event_read, }; -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_EVENT_TRACING void perf_tp_event(int event_id, u64 addr, u64 count, void *record, int entry_size) @@ -4282,7 +4282,7 @@ static void perf_event_free_filter(struct perf_event *event) { } -#endif /* CONFIG_EVENT_PROFILE */ +#endif /* CONFIG_EVENT_TRACING */ #ifdef CONFIG_HAVE_HW_BREAKPOINT static void bp_perf_event_destroy(struct perf_event *event) diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index cd9ecd89ec77..d00c6fe23f54 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -51,7 +51,9 @@ endif obj-$(CONFIG_EVENT_TRACING) += trace_events.o obj-$(CONFIG_EVENT_TRACING) += trace_export.o obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o -obj-$(CONFIG_EVENT_PROFILE) += trace_event_profile.o +ifeq ($(CONFIG_PERF_EVENTS),y) +obj-$(CONFIG_EVENT_TRACING) += trace_event_profile.o +endif obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o obj-$(CONFIG_KSYM_TRACER) += trace_ksym.o diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 50504cb228de..74563d7e102e 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1360,7 +1360,7 @@ out_unlock: return err; } -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS void ftrace_profile_free_filter(struct perf_event *event) { @@ -1428,5 +1428,5 @@ out_unlock: return err; } -#endif /* CONFIG_EVENT_PROFILE */ +#endif /* CONFIG_PERF_EVENTS */ diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 375f81a568dc..75d75dec226a 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1249,7 +1249,7 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, ", REC->" FIELD_STRING_RETIP); } -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS /* Kprobe profile handler */ static __kprobes int kprobe_profile_func(struct kprobe *kp, @@ -1407,7 +1407,7 @@ static void probe_profile_disable(struct ftrace_event_call *call) disable_kprobe(&tp->rp.kp); } } -#endif /* CONFIG_EVENT_PROFILE */ +#endif /* CONFIG_PERF_EVENTS */ static __kprobes @@ -1417,10 +1417,10 @@ int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) if (tp->flags & TP_FLAG_TRACE) kprobe_trace_func(kp, regs); -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS if (tp->flags & TP_FLAG_PROFILE) kprobe_profile_func(kp, regs); -#endif /* CONFIG_EVENT_PROFILE */ +#endif return 0; /* We don't tweek kernel, so just return 0 */ } @@ -1431,10 +1431,10 @@ int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) if (tp->flags & TP_FLAG_TRACE) kretprobe_trace_func(ri, regs); -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS if (tp->flags & TP_FLAG_PROFILE) kretprobe_profile_func(ri, regs); -#endif /* CONFIG_EVENT_PROFILE */ +#endif return 0; /* We don't tweek kernel, so just return 0 */ } @@ -1463,7 +1463,7 @@ static int register_probe_event(struct trace_probe *tp) call->regfunc = probe_event_enable; call->unregfunc = probe_event_disable; -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS call->profile_enable = probe_profile_enable; call->profile_disable = probe_profile_disable; #endif diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 75289f372dd2..f694f66d75b0 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -421,7 +421,7 @@ int __init init_ftrace_syscalls(void) } core_initcall(init_ftrace_syscalls); -#ifdef CONFIG_EVENT_PROFILE +#ifdef CONFIG_PERF_EVENTS static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls); static DECLARE_BITMAP(enabled_prof_exit_syscalls, NR_syscalls); @@ -626,6 +626,5 @@ void prof_sysexit_disable(struct ftrace_event_call *call) mutex_unlock(&syscall_trace_lock); } -#endif - +#endif /* CONFIG_PERF_EVENTS */ -- cgit v1.2.3 From d894837f23f491aa7ed167aae767fc07cfe6e6e6 Mon Sep 17 00:00:00 2001 From: Simon Kagstrom Date: Wed, 23 Dec 2009 11:08:18 +0100 Subject: sched: might_sleep(): Make file parameter const char * Fixes a warning when building with g++: warning: deprecated conversion from string constant to 'char*' And the file parameter use is constant, so mark it as such. Signed-off-by: Simon Kagstrom Cc: peterz@infradead.org LKML-Reference: <20091223110818.442d848e@marrow.netinsight.se> Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 5 +++-- kernel/sched.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fc9f5aab5f8..785d7d1099d4 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -124,7 +124,7 @@ extern int _cond_resched(void); #endif #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP - void __might_sleep(char *file, int line, int preempt_offset); + void __might_sleep(const char *file, int line, int preempt_offset); /** * might_sleep - annotation for functions that can sleep * @@ -138,7 +138,8 @@ extern int _cond_resched(void); # define might_sleep() \ do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) #else - static inline void __might_sleep(char *file, int line, int preempt_offset) { } + static inline void __might_sleep(const char *file, int line, + int preempt_offset) { } # define might_sleep() do { might_resched(); } while (0) #endif diff --git a/kernel/sched.c b/kernel/sched.c index c535cc4f6428..64298a52eaa6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -9694,7 +9694,7 @@ static inline int preempt_count_equals(int preempt_offset) return (nested == PREEMPT_INATOMIC_BASE + preempt_offset); } -void __might_sleep(char *file, int line, int preempt_offset) +void __might_sleep(const char *file, int line, int preempt_offset) { #ifdef in_atomic static unsigned long prev_jiffy; /* ratelimiting */ -- cgit v1.2.3 From 16295bec6398a3eedc9377e1af6ff4c71b98c300 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Wed, 6 Jan 2010 19:47:10 +1100 Subject: padata: Generic parallelization/serialization interface This patch introduces an interface to process data objects in parallel. The parallelized objects return after serialization in the same order as they were before the parallelization. Signed-off-by: Steffen Klassert Signed-off-by: Herbert Xu --- include/linux/padata.h | 88 +++++++ init/Kconfig | 4 + kernel/Makefile | 1 + kernel/padata.c | 690 +++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 783 insertions(+) create mode 100644 include/linux/padata.h create mode 100644 kernel/padata.c (limited to 'kernel') diff --git a/include/linux/padata.h b/include/linux/padata.h new file mode 100644 index 000000000000..51611da9c498 --- /dev/null +++ b/include/linux/padata.h @@ -0,0 +1,88 @@ +/* + * padata.h - header for the padata parallelization interface + * + * Copyright (C) 2008, 2009 secunet Security Networks AG + * Copyright (C) 2008, 2009 Steffen Klassert + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef PADATA_H +#define PADATA_H + +#include +#include +#include + +struct padata_priv { + struct list_head list; + struct parallel_data *pd; + int cb_cpu; + int seq_nr; + int info; + void (*parallel)(struct padata_priv *padata); + void (*serial)(struct padata_priv *padata); +}; + +struct padata_list { + struct list_head list; + spinlock_t lock; +}; + +struct padata_queue { + struct padata_list parallel; + struct padata_list reorder; + struct padata_list serial; + struct work_struct pwork; + struct work_struct swork; + struct parallel_data *pd; + atomic_t num_obj; + int cpu_index; +}; + +struct parallel_data { + struct padata_instance *pinst; + struct padata_queue *queue; + atomic_t seq_nr; + atomic_t reorder_objects; + atomic_t refcnt; + unsigned int max_seq_nr; + cpumask_var_t cpumask; + spinlock_t lock; +}; + +struct padata_instance { + struct notifier_block cpu_notifier; + struct workqueue_struct *wq; + struct parallel_data *pd; + cpumask_var_t cpumask; + struct mutex lock; + u8 flags; +#define PADATA_INIT 1 +#define PADATA_RESET 2 +}; + +extern struct padata_instance *padata_alloc(const struct cpumask *cpumask, + struct workqueue_struct *wq); +extern void padata_free(struct padata_instance *pinst); +extern int padata_do_parallel(struct padata_instance *pinst, + struct padata_priv *padata, int cb_cpu); +extern void padata_do_serial(struct padata_priv *padata); +extern int padata_set_cpumask(struct padata_instance *pinst, + cpumask_var_t cpumask); +extern int padata_add_cpu(struct padata_instance *pinst, int cpu); +extern int padata_remove_cpu(struct padata_instance *pinst, int cpu); +extern void padata_start(struct padata_instance *pinst); +extern void padata_stop(struct padata_instance *pinst); +#endif diff --git a/init/Kconfig b/init/Kconfig index a23da9f01803..9fd23bcc1709 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1252,4 +1252,8 @@ source "block/Kconfig" config PREEMPT_NOTIFIERS bool +config PADATA + depends on SMP + bool + source "kernel/Kconfig.locks" diff --git a/kernel/Makefile b/kernel/Makefile index 864ff75d65f2..6aebdeb2aa34 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -100,6 +100,7 @@ obj-$(CONFIG_SLOW_WORK_DEBUG) += slow-work-debugfs.o obj-$(CONFIG_PERF_EVENTS) += perf_event.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_USER_RETURN_NOTIFIER) += user-return-notifier.o +obj-$(CONFIG_PADATA) += padata.o ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y) # According to Alan Modra , the -fno-omit-frame-pointer is diff --git a/kernel/padata.c b/kernel/padata.c new file mode 100644 index 000000000000..6f9bcb8313d6 --- /dev/null +++ b/kernel/padata.c @@ -0,0 +1,690 @@ +/* + * padata.c - generic interface to process data streams in parallel + * + * Copyright (C) 2008, 2009 secunet Security Networks AG + * Copyright (C) 2008, 2009 Steffen Klassert + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define MAX_SEQ_NR INT_MAX - NR_CPUS +#define MAX_OBJ_NUM 10000 * NR_CPUS + +static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index) +{ + int cpu, target_cpu; + + target_cpu = cpumask_first(pd->cpumask); + for (cpu = 0; cpu < cpu_index; cpu++) + target_cpu = cpumask_next(target_cpu, pd->cpumask); + + return target_cpu; +} + +static int padata_cpu_hash(struct padata_priv *padata) +{ + int cpu_index; + struct parallel_data *pd; + + pd = padata->pd; + + /* + * Hash the sequence numbers to the cpus by taking + * seq_nr mod. number of cpus in use. + */ + cpu_index = padata->seq_nr % cpumask_weight(pd->cpumask); + + return padata_index_to_cpu(pd, cpu_index); +} + +static void padata_parallel_worker(struct work_struct *work) +{ + struct padata_queue *queue; + struct parallel_data *pd; + struct padata_instance *pinst; + LIST_HEAD(local_list); + + local_bh_disable(); + queue = container_of(work, struct padata_queue, pwork); + pd = queue->pd; + pinst = pd->pinst; + + spin_lock(&queue->parallel.lock); + list_replace_init(&queue->parallel.list, &local_list); + spin_unlock(&queue->parallel.lock); + + while (!list_empty(&local_list)) { + struct padata_priv *padata; + + padata = list_entry(local_list.next, + struct padata_priv, list); + + list_del_init(&padata->list); + + padata->parallel(padata); + } + + local_bh_enable(); +} + +/* + * padata_do_parallel - padata parallelization function + * + * @pinst: padata instance + * @padata: object to be parallelized + * @cb_cpu: cpu the serialization callback function will run on, + * must be in the cpumask of padata. + * + * The parallelization callback function will run with BHs off. + * Note: Every object which is parallelized by padata_do_parallel + * must be seen by padata_do_serial. + */ +int padata_do_parallel(struct padata_instance *pinst, + struct padata_priv *padata, int cb_cpu) +{ + int target_cpu, err; + struct padata_queue *queue; + struct parallel_data *pd; + + rcu_read_lock_bh(); + + pd = rcu_dereference(pinst->pd); + + err = 0; + if (!(pinst->flags & PADATA_INIT)) + goto out; + + err = -EBUSY; + if ((pinst->flags & PADATA_RESET)) + goto out; + + if (atomic_read(&pd->refcnt) >= MAX_OBJ_NUM) + goto out; + + err = -EINVAL; + if (!cpumask_test_cpu(cb_cpu, pd->cpumask)) + goto out; + + err = -EINPROGRESS; + atomic_inc(&pd->refcnt); + padata->pd = pd; + padata->cb_cpu = cb_cpu; + + if (unlikely(atomic_read(&pd->seq_nr) == pd->max_seq_nr)) + atomic_set(&pd->seq_nr, -1); + + padata->seq_nr = atomic_inc_return(&pd->seq_nr); + + target_cpu = padata_cpu_hash(padata); + queue = per_cpu_ptr(pd->queue, target_cpu); + + spin_lock(&queue->parallel.lock); + list_add_tail(&padata->list, &queue->parallel.list); + spin_unlock(&queue->parallel.lock); + + queue_work_on(target_cpu, pinst->wq, &queue->pwork); + +out: + rcu_read_unlock_bh(); + + return err; +} +EXPORT_SYMBOL(padata_do_parallel); + +static struct padata_priv *padata_get_next(struct parallel_data *pd) +{ + int cpu, num_cpus, empty, calc_seq_nr; + int seq_nr, next_nr, overrun, next_overrun; + struct padata_queue *queue, *next_queue; + struct padata_priv *padata; + struct padata_list *reorder; + + empty = 0; + next_nr = -1; + next_overrun = 0; + next_queue = NULL; + + num_cpus = cpumask_weight(pd->cpumask); + + for_each_cpu(cpu, pd->cpumask) { + queue = per_cpu_ptr(pd->queue, cpu); + reorder = &queue->reorder; + + /* + * Calculate the seq_nr of the object that should be + * next in this queue. + */ + overrun = 0; + calc_seq_nr = (atomic_read(&queue->num_obj) * num_cpus) + + queue->cpu_index; + + if (unlikely(calc_seq_nr > pd->max_seq_nr)) { + calc_seq_nr = calc_seq_nr - pd->max_seq_nr - 1; + overrun = 1; + } + + if (!list_empty(&reorder->list)) { + padata = list_entry(reorder->list.next, + struct padata_priv, list); + + seq_nr = padata->seq_nr; + BUG_ON(calc_seq_nr != seq_nr); + } else { + seq_nr = calc_seq_nr; + empty++; + } + + if (next_nr < 0 || seq_nr < next_nr + || (next_overrun && !overrun)) { + next_nr = seq_nr; + next_overrun = overrun; + next_queue = queue; + } + } + + padata = NULL; + + if (empty == num_cpus) + goto out; + + reorder = &next_queue->reorder; + + if (!list_empty(&reorder->list)) { + padata = list_entry(reorder->list.next, + struct padata_priv, list); + + if (unlikely(next_overrun)) { + for_each_cpu(cpu, pd->cpumask) { + queue = per_cpu_ptr(pd->queue, cpu); + atomic_set(&queue->num_obj, 0); + } + } + + spin_lock(&reorder->lock); + list_del_init(&padata->list); + atomic_dec(&pd->reorder_objects); + spin_unlock(&reorder->lock); + + atomic_inc(&next_queue->num_obj); + + goto out; + } + + if (next_nr % num_cpus == next_queue->cpu_index) { + padata = ERR_PTR(-ENODATA); + goto out; + } + + padata = ERR_PTR(-EINPROGRESS); +out: + return padata; +} + +static void padata_reorder(struct parallel_data *pd) +{ + struct padata_priv *padata; + struct padata_queue *queue; + struct padata_instance *pinst = pd->pinst; + +try_again: + if (!spin_trylock_bh(&pd->lock)) + goto out; + + while (1) { + padata = padata_get_next(pd); + + if (!padata || PTR_ERR(padata) == -EINPROGRESS) + break; + + if (PTR_ERR(padata) == -ENODATA) { + spin_unlock_bh(&pd->lock); + goto out; + } + + queue = per_cpu_ptr(pd->queue, padata->cb_cpu); + + spin_lock(&queue->serial.lock); + list_add_tail(&padata->list, &queue->serial.list); + spin_unlock(&queue->serial.lock); + + queue_work_on(padata->cb_cpu, pinst->wq, &queue->swork); + } + + spin_unlock_bh(&pd->lock); + + if (atomic_read(&pd->reorder_objects)) + goto try_again; + +out: + return; +} + +static void padata_serial_worker(struct work_struct *work) +{ + struct padata_queue *queue; + struct parallel_data *pd; + LIST_HEAD(local_list); + + local_bh_disable(); + queue = container_of(work, struct padata_queue, swork); + pd = queue->pd; + + spin_lock(&queue->serial.lock); + list_replace_init(&queue->serial.list, &local_list); + spin_unlock(&queue->serial.lock); + + while (!list_empty(&local_list)) { + struct padata_priv *padata; + + padata = list_entry(local_list.next, + struct padata_priv, list); + + list_del_init(&padata->list); + + padata->serial(padata); + atomic_dec(&pd->refcnt); + } + local_bh_enable(); +} + +/* + * padata_do_serial - padata serialization function + * + * @padata: object to be serialized. + * + * padata_do_serial must be called for every parallelized object. + * The serialization callback function will run with BHs off. + */ +void padata_do_serial(struct padata_priv *padata) +{ + int cpu; + struct padata_queue *queue; + struct parallel_data *pd; + + pd = padata->pd; + + cpu = get_cpu(); + queue = per_cpu_ptr(pd->queue, cpu); + + spin_lock(&queue->reorder.lock); + atomic_inc(&pd->reorder_objects); + list_add_tail(&padata->list, &queue->reorder.list); + spin_unlock(&queue->reorder.lock); + + put_cpu(); + + padata_reorder(pd); +} +EXPORT_SYMBOL(padata_do_serial); + +static struct parallel_data *padata_alloc_pd(struct padata_instance *pinst, + const struct cpumask *cpumask) +{ + int cpu, cpu_index, num_cpus; + struct padata_queue *queue; + struct parallel_data *pd; + + cpu_index = 0; + + pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL); + if (!pd) + goto err; + + pd->queue = alloc_percpu(struct padata_queue); + if (!pd->queue) + goto err_free_pd; + + if (!alloc_cpumask_var(&pd->cpumask, GFP_KERNEL)) + goto err_free_queue; + + for_each_possible_cpu(cpu) { + queue = per_cpu_ptr(pd->queue, cpu); + + queue->pd = pd; + + if (cpumask_test_cpu(cpu, cpumask) + && cpumask_test_cpu(cpu, cpu_active_mask)) { + queue->cpu_index = cpu_index; + cpu_index++; + } else + queue->cpu_index = -1; + + INIT_LIST_HEAD(&queue->reorder.list); + INIT_LIST_HEAD(&queue->parallel.list); + INIT_LIST_HEAD(&queue->serial.list); + spin_lock_init(&queue->reorder.lock); + spin_lock_init(&queue->parallel.lock); + spin_lock_init(&queue->serial.lock); + + INIT_WORK(&queue->pwork, padata_parallel_worker); + INIT_WORK(&queue->swork, padata_serial_worker); + atomic_set(&queue->num_obj, 0); + } + + cpumask_and(pd->cpumask, cpumask, cpu_active_mask); + + num_cpus = cpumask_weight(pd->cpumask); + pd->max_seq_nr = (MAX_SEQ_NR / num_cpus) * num_cpus - 1; + + atomic_set(&pd->seq_nr, -1); + atomic_set(&pd->reorder_objects, 0); + atomic_set(&pd->refcnt, 0); + pd->pinst = pinst; + spin_lock_init(&pd->lock); + + return pd; + +err_free_queue: + free_percpu(pd->queue); +err_free_pd: + kfree(pd); +err: + return NULL; +} + +static void padata_free_pd(struct parallel_data *pd) +{ + free_cpumask_var(pd->cpumask); + free_percpu(pd->queue); + kfree(pd); +} + +static void padata_replace(struct padata_instance *pinst, + struct parallel_data *pd_new) +{ + struct parallel_data *pd_old = pinst->pd; + + pinst->flags |= PADATA_RESET; + + rcu_assign_pointer(pinst->pd, pd_new); + + synchronize_rcu(); + + while (atomic_read(&pd_old->refcnt) != 0) + yield(); + + flush_workqueue(pinst->wq); + + padata_free_pd(pd_old); + + pinst->flags &= ~PADATA_RESET; +} + +/* + * padata_set_cpumask - set the cpumask that padata should use + * + * @pinst: padata instance + * @cpumask: the cpumask to use + */ +int padata_set_cpumask(struct padata_instance *pinst, + cpumask_var_t cpumask) +{ + struct parallel_data *pd; + int err = 0; + + might_sleep(); + + mutex_lock(&pinst->lock); + + pd = padata_alloc_pd(pinst, cpumask); + if (!pd) { + err = -ENOMEM; + goto out; + } + + cpumask_copy(pinst->cpumask, cpumask); + + padata_replace(pinst, pd); + +out: + mutex_unlock(&pinst->lock); + + return err; +} +EXPORT_SYMBOL(padata_set_cpumask); + +static int __padata_add_cpu(struct padata_instance *pinst, int cpu) +{ + struct parallel_data *pd; + + if (cpumask_test_cpu(cpu, cpu_active_mask)) { + pd = padata_alloc_pd(pinst, pinst->cpumask); + if (!pd) + return -ENOMEM; + + padata_replace(pinst, pd); + } + + return 0; +} + +/* + * padata_add_cpu - add a cpu to the padata cpumask + * + * @pinst: padata instance + * @cpu: cpu to add + */ +int padata_add_cpu(struct padata_instance *pinst, int cpu) +{ + int err; + + might_sleep(); + + mutex_lock(&pinst->lock); + + cpumask_set_cpu(cpu, pinst->cpumask); + err = __padata_add_cpu(pinst, cpu); + + mutex_unlock(&pinst->lock); + + return err; +} +EXPORT_SYMBOL(padata_add_cpu); + +static int __padata_remove_cpu(struct padata_instance *pinst, int cpu) +{ + struct parallel_data *pd; + + if (cpumask_test_cpu(cpu, cpu_online_mask)) { + pd = padata_alloc_pd(pinst, pinst->cpumask); + if (!pd) + return -ENOMEM; + + padata_replace(pinst, pd); + } + + return 0; +} + +/* + * padata_remove_cpu - remove a cpu from the padata cpumask + * + * @pinst: padata instance + * @cpu: cpu to remove + */ +int padata_remove_cpu(struct padata_instance *pinst, int cpu) +{ + int err; + + might_sleep(); + + mutex_lock(&pinst->lock); + + cpumask_clear_cpu(cpu, pinst->cpumask); + err = __padata_remove_cpu(pinst, cpu); + + mutex_unlock(&pinst->lock); + + return err; +} +EXPORT_SYMBOL(padata_remove_cpu); + +/* + * padata_start - start the parallel processing + * + * @pinst: padata instance to start + */ +void padata_start(struct padata_instance *pinst) +{ + might_sleep(); + + mutex_lock(&pinst->lock); + pinst->flags |= PADATA_INIT; + mutex_unlock(&pinst->lock); +} +EXPORT_SYMBOL(padata_start); + +/* + * padata_stop - stop the parallel processing + * + * @pinst: padata instance to stop + */ +void padata_stop(struct padata_instance *pinst) +{ + might_sleep(); + + mutex_lock(&pinst->lock); + pinst->flags &= ~PADATA_INIT; + mutex_unlock(&pinst->lock); +} +EXPORT_SYMBOL(padata_stop); + +static int __cpuinit padata_cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + int err; + struct padata_instance *pinst; + int cpu = (unsigned long)hcpu; + + pinst = container_of(nfb, struct padata_instance, cpu_notifier); + + switch (action) { + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + if (!cpumask_test_cpu(cpu, pinst->cpumask)) + break; + mutex_lock(&pinst->lock); + err = __padata_add_cpu(pinst, cpu); + mutex_unlock(&pinst->lock); + if (err) + return NOTIFY_BAD; + break; + + case CPU_DOWN_PREPARE: + case CPU_DOWN_PREPARE_FROZEN: + if (!cpumask_test_cpu(cpu, pinst->cpumask)) + break; + mutex_lock(&pinst->lock); + err = __padata_remove_cpu(pinst, cpu); + mutex_unlock(&pinst->lock); + if (err) + return NOTIFY_BAD; + break; + + case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: + if (!cpumask_test_cpu(cpu, pinst->cpumask)) + break; + mutex_lock(&pinst->lock); + __padata_remove_cpu(pinst, cpu); + mutex_unlock(&pinst->lock); + + case CPU_DOWN_FAILED: + case CPU_DOWN_FAILED_FROZEN: + if (!cpumask_test_cpu(cpu, pinst->cpumask)) + break; + mutex_lock(&pinst->lock); + __padata_add_cpu(pinst, cpu); + mutex_unlock(&pinst->lock); + } + + return NOTIFY_OK; +} + +/* + * padata_alloc - allocate and initialize a padata instance + * + * @cpumask: cpumask that padata uses for parallelization + * @wq: workqueue to use for the allocated padata instance + */ +struct padata_instance *padata_alloc(const struct cpumask *cpumask, + struct workqueue_struct *wq) +{ + int err; + struct padata_instance *pinst; + struct parallel_data *pd; + + pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL); + if (!pinst) + goto err; + + pd = padata_alloc_pd(pinst, cpumask); + if (!pd) + goto err_free_inst; + + rcu_assign_pointer(pinst->pd, pd); + + pinst->wq = wq; + + cpumask_copy(pinst->cpumask, cpumask); + + pinst->flags = 0; + + pinst->cpu_notifier.notifier_call = padata_cpu_callback; + pinst->cpu_notifier.priority = 0; + err = register_hotcpu_notifier(&pinst->cpu_notifier); + if (err) + goto err_free_pd; + + mutex_init(&pinst->lock); + + return pinst; + +err_free_pd: + padata_free_pd(pd); +err_free_inst: + kfree(pinst); +err: + return NULL; +} +EXPORT_SYMBOL(padata_alloc); + +/* + * padata_free - free a padata instance + * + * @ padata_inst: padata instance to free + */ +void padata_free(struct padata_instance *pinst) +{ + padata_stop(pinst); + + synchronize_rcu(); + + while (atomic_read(&pinst->pd->refcnt) != 0) + yield(); + + unregister_hotcpu_notifier(&pinst->cpu_notifier); + padata_free_pd(pinst->pd); + kfree(pinst); +} +EXPORT_SYMBOL(padata_free); -- cgit v1.2.3 From 809826a389040e0ad9d646b587bccc0e34691afd Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Dec 2009 15:39:34 +0800 Subject: tracing: Have __dynamic_array() define a field This is part of a patch set that removes the show_format method in the ftrace event macros. This patch set requires that all fields are added to the ftrace_event_call->fields. This patch changes __dynamic_array() to call trace_define_field() to include fields that use __dynamic_array(). Signed-off-by: Lai Jiangshan LKML-Reference: <4B273D36.8090100@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_export.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index d4fa5dc1ee4e..9978a4f40090 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -175,7 +175,12 @@ ftrace_format_##name(struct ftrace_event_call *unused, \ return ret; #undef __dynamic_array -#define __dynamic_array(type, item) +#define __dynamic_array(type, item) \ + ret = trace_define_field(event_call, #type, #item, \ + offsetof(typeof(field), item), \ + 0, is_signed_type(type), FILTER_OTHER);\ + if (ret) \ + return ret; #undef FTRACE_ENTRY #define FTRACE_ENTRY(name, struct_name, id, tstruct, print) \ -- cgit v1.2.3 From 509e760cd91c831983097ae174cb6c0b8c6c8e6b Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Dec 2009 15:39:42 +0800 Subject: tracing: Add print_fmt field This is part of a patch set that removes the show_format method in the ftrace event macros. The print_fmt field is added to hold the string that shows the print_fmt in the event format files. This patch only adds the field but it is currently not used. Later patches will use this field to enable us to remove the show_format field and function. Signed-off-by: Lai Jiangshan LKML-Reference: <4B273D3E.2000704@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 1 + include/trace/ftrace.h | 28 +++++++++++++++++++++++++++- kernel/trace/trace_export.c | 7 +++++++ 3 files changed, 35 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 2233c98d80df..bd23d8e52f02 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -121,6 +121,7 @@ struct ftrace_event_call { int (*regfunc)(struct ftrace_event_call *); void (*unregfunc)(struct ftrace_event_call *); int id; + const char *print_fmt; int (*raw_init)(struct ftrace_event_call *); int (*show_format)(struct ftrace_event_call *, struct trace_seq *); diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index c6fe03e902ca..3351d85c83a3 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -722,8 +722,20 @@ static struct trace_event ftrace_event_type_##call = { \ #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) +#undef __entry +#define __entry REC + +#undef __print_flags +#undef __print_symbolic +#undef __get_dynamic_array +#undef __get_str + +#undef TP_printk +#define TP_printk(fmt, args...) "\"" fmt "\", " __stringify(args) + #undef DECLARE_EVENT_CLASS -#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) +#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ +static const char print_fmt_##call[] = print; #undef DEFINE_EVENT #define DEFINE_EVENT(template, call, proto, args) \ @@ -737,6 +749,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ .raw_init = trace_event_raw_init, \ .regfunc = ftrace_raw_reg_event_##call, \ .unregfunc = ftrace_raw_unreg_event_##call, \ + .print_fmt = print_fmt_##template, \ .show_format = ftrace_format_##template, \ .define_fields = ftrace_define_fields_##template, \ _TRACE_PROFILE_INIT(call) \ @@ -745,6 +758,8 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ #undef DEFINE_EVENT_PRINT #define DEFINE_EVENT_PRINT(template, call, proto, args, print) \ \ +static const char print_fmt_##call[] = print; \ + \ static struct ftrace_event_call __used \ __attribute__((__aligned__(4))) \ __attribute__((section("_ftrace_events"))) event_##call = { \ @@ -754,6 +769,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ .raw_init = trace_event_raw_init, \ .regfunc = ftrace_raw_reg_event_##call, \ .unregfunc = ftrace_raw_unreg_event_##call, \ + .print_fmt = print_fmt_##call, \ .show_format = ftrace_format_##call, \ .define_fields = ftrace_define_fields_##template, \ _TRACE_PROFILE_INIT(call) \ @@ -837,6 +853,16 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ #ifdef CONFIG_EVENT_PROFILE +#undef __entry +#define __entry entry + +#undef __get_dynamic_array +#define __get_dynamic_array(field) \ + ((void *)__entry + (__entry->__data_loc_##field & 0xffff)) + +#undef __get_str +#define __get_str(field) (char *)__get_dynamic_array(field) + #undef __perf_addr #define __perf_addr(a) __addr = (a) diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 9978a4f40090..95d14b640a66 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -203,6 +203,9 @@ static int ftrace_raw_init_event(struct ftrace_event_call *call) return 0; } +#undef __entry +#define __entry REC + #undef __field #define __field(type, item) @@ -218,6 +221,9 @@ static int ftrace_raw_init_event(struct ftrace_event_call *call) #undef __dynamic_array #define __dynamic_array(type, item) +#undef F_printk +#define F_printk(fmt, args...) #fmt ", " __stringify(args) + #undef FTRACE_ENTRY #define FTRACE_ENTRY(call, struct_name, type, tstruct, print) \ \ @@ -228,6 +234,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ .id = type, \ .system = __stringify(TRACE_SYSTEM), \ .raw_init = ftrace_raw_init_event, \ + .print_fmt = print, \ .show_format = ftrace_format_##call, \ .define_fields = ftrace_define_fields_##call, \ }; \ -- cgit v1.2.3 From 50307a45f8515f6244e3b08e6b19824b9fbfe293 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Dec 2009 15:39:45 +0800 Subject: tracing/syscalls: Init print_fmt for syscall events This is part of a patch set that removes the show_format method in the ftrace event macros. Add the print_fmt initialization to the syscall events. The print_fmt is still not used, but will be in the follow up patches. Signed-off-by: Lai Jiangshan LKML-Reference: <4B273D41.609@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_syscalls.c | 68 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 67 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 75289f372dd2..1352b0a36fac 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -191,6 +191,67 @@ int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s) return trace_seq_putc(s, '\n'); } +static +int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len) +{ + int i; + int pos = 0; + + /* When len=0, we just calculate the needed length */ +#define LEN_OR_ZERO (len ? len - pos : 0) + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); + for (i = 0; i < entry->nb_args; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s", + entry->args[i], sizeof(unsigned long), + i == entry->nb_args - 1 ? "" : ", "); + } + pos += snprintf(buf + pos, LEN_OR_ZERO, "\""); + + for (i = 0; i < entry->nb_args; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, + ", ((unsigned long)(REC->%s))", entry->args[i]); + } + +#undef LEN_OR_ZERO + + /* return the length of print_fmt */ + return pos; +} + +static int set_syscall_print_fmt(struct ftrace_event_call *call) +{ + char *print_fmt; + int len; + struct syscall_metadata *entry = call->data; + + if (entry->enter_event != call) { + call->print_fmt = "\"0x%lx\", REC->ret"; + return 0; + } + + /* First: called with 0 length to calculate the needed length */ + len = __set_enter_print_fmt(entry, NULL, 0); + + print_fmt = kmalloc(len + 1, GFP_KERNEL); + if (!print_fmt) + return -ENOMEM; + + /* Second: actually write the @print_fmt */ + __set_enter_print_fmt(entry, print_fmt, len + 1); + call->print_fmt = print_fmt; + + return 0; +} + +static void free_syscall_print_fmt(struct ftrace_event_call *call) +{ + struct syscall_metadata *entry = call->data; + + if (entry->enter_event == call) + kfree(call->print_fmt); +} + int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s) { int ret; @@ -386,9 +447,14 @@ int init_syscall_trace(struct ftrace_event_call *call) { int id; + if (set_syscall_print_fmt(call) < 0) + return -ENOMEM; + id = register_ftrace_event(call->event); - if (!id) + if (!id) { + free_syscall_print_fmt(call); return -ENODEV; + } call->id = id; INIT_LIST_HEAD(&call->fields); return 0; -- cgit v1.2.3 From a342a0280b981c130e32dbb94dbd3a57959c4d04 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Dec 2009 15:39:49 +0800 Subject: tracing/kprobes: Init print_fmt for kprobe events This is part of a patch set that removes the show_format method in the ftrace event macros. Add the print_fmt initialization to the kprobe events. The print_fmt is still not used, but will be in the follow up patches. Signed-off-by: Lai Jiangshan LKML-Reference: <4B273D45.3080100@cn.fujitsu.com> Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/trace/trace_kprobe.c | 64 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 63 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 6ea90c0e2c96..147491dccead 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1250,6 +1250,62 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, ", REC->" FIELD_STRING_RETIP); } +static int __set_print_fmt(struct trace_probe *tp, char *buf, int len) +{ + int i; + int pos = 0; + + const char *fmt, *arg; + + if (!probe_is_return(tp)) { + fmt = "(%lx)"; + arg = "REC->" FIELD_STRING_IP; + } else { + fmt = "(%lx <- %lx)"; + arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; + } + + /* When len=0, we just calculate the needed length */ +#define LEN_OR_ZERO (len ? len - pos : 0) + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); + + for (i = 0; i < tp->nr_args; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%%lx", + tp->args[i].name); + } + + pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg); + + for (i = 0; i < tp->nr_args; i++) { + pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", + tp->args[i].name); + } + +#undef LEN_OR_ZERO + + /* return the length of print_fmt */ + return pos; +} + +static int set_print_fmt(struct trace_probe *tp) +{ + int len; + char *print_fmt; + + /* First: called with 0 length to calculate the needed length */ + len = __set_print_fmt(tp, NULL, 0); + print_fmt = kmalloc(len + 1, GFP_KERNEL); + if (!print_fmt) + return -ENOMEM; + + /* Second: actually write the @print_fmt */ + __set_print_fmt(tp, print_fmt, len + 1); + tp->call.print_fmt = print_fmt; + + return 0; +} + #ifdef CONFIG_EVENT_PROFILE /* Kprobe profile handler */ @@ -1456,10 +1512,14 @@ static int register_probe_event(struct trace_probe *tp) call->show_format = kprobe_event_show_format; call->define_fields = kprobe_event_define_fields; } + if (set_print_fmt(tp) < 0) + return -ENOMEM; call->event = &tp->event; call->id = register_ftrace_event(&tp->event); - if (!call->id) + if (!call->id) { + kfree(call->print_fmt); return -ENODEV; + } call->enabled = 0; call->regfunc = probe_event_enable; call->unregfunc = probe_event_disable; @@ -1472,6 +1532,7 @@ static int register_probe_event(struct trace_probe *tp) ret = trace_add_event_call(call); if (ret) { pr_info("Failed to register kprobe event: %s\n", call->name); + kfree(call->print_fmt); unregister_ftrace_event(&tp->event); } return ret; @@ -1481,6 +1542,7 @@ static void unregister_probe_event(struct trace_probe *tp) { /* tp->event is unregistered in trace_remove_event_call() */ trace_remove_event_call(&tp->call); + kfree(tp->call.print_fmt); } /* Make a debugfs interface for controling probe points */ -- cgit v1.2.3 From c7ef3a9004201bca90626db246a19dadd2c29c9b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 28 Dec 2009 21:13:59 -0500 Subject: tracing: Have syscall tracing call its own init function In the clean up of having all events call one specific function, the syscall event init was changed to call this helper function. With the new print_fmt updates, the syscalls need to do special initializations. This patch converts the syscall events to call its own init function again. Cc: Lai Jiangshan Cc: Li Zefan Signed-off-by: Steven Rostedt --- include/linux/syscalls.h | 4 ++-- kernel/trace/trace_syscalls.c | 12 ++++++------ 2 files changed, 8 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 207466a49f3d..ed353d274a77 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -143,7 +143,7 @@ struct perf_event_attr; .name = "sys_enter"#sname, \ .system = "syscalls", \ .event = &enter_syscall_print_##sname, \ - .raw_init = trace_event_raw_init, \ + .raw_init = init_syscall_trace, \ .show_format = syscall_enter_format, \ .define_fields = syscall_enter_define_fields, \ .regfunc = reg_event_syscall_enter, \ @@ -165,7 +165,7 @@ struct perf_event_attr; .name = "sys_exit"#sname, \ .system = "syscalls", \ .event = &exit_syscall_print_##sname, \ - .raw_init = trace_event_raw_init, \ + .raw_init = init_syscall_trace, \ .show_format = syscall_exit_format, \ .define_fields = syscall_exit_define_fields, \ .regfunc = reg_event_syscall_exit, \ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 1352b0a36fac..a78e86349ecb 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -450,14 +450,14 @@ int init_syscall_trace(struct ftrace_event_call *call) if (set_syscall_print_fmt(call) < 0) return -ENOMEM; - id = register_ftrace_event(call->event); - if (!id) { + id = trace_event_raw_init(call); + + if (id < 0) { free_syscall_print_fmt(call); - return -ENODEV; + return id; } - call->id = id; - INIT_LIST_HEAD(&call->fields); - return 0; + + return id; } int __init init_ftrace_syscalls(void) -- cgit v1.2.3 From 5a65e956220efc2421e21ee56d6153fd5c533a95 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Dec 2009 15:39:53 +0800 Subject: tracing: Use defined fields and print_fmt to print formats The calls ftrace_format_##call() and ftrace_define_fields_##call() are almost duplicate in functionality. With the addition of the print_fmt in previous patches, these two functions can be merged into one. The trace_define_field() defines the fields and links them into the struct ftrace_event_call. The previous patches introduced the print_fmt field and this can now be used with the trace_define_field() to create the event format file fields and print_fmt field. The struct ftrace_event_call->fields are used to print the fields The struct ftrace_event_call->print_fmt is used to print the "print fmt: XXXXXXXXXXX" line. Signed-off-by: Lai Jiangshan LKML-Reference: <4B273D49.5000006@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 65 ++++++++++++++++++++++++++++----------------- 1 file changed, 41 insertions(+), 24 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 189b09baf4fb..250ec865d5f5 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -528,33 +528,16 @@ extern char *__bad_type_size(void); #type, "common_" #name, offsetof(typeof(field), name), \ sizeof(field.name), is_signed_type(type) -static int trace_write_header(struct trace_seq *s) -{ - struct trace_entry field; - - /* struct trace_entry */ - return trace_seq_printf(s, - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n" - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n" - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n" - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n" - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;\tsigned:%u;\n" - "\n", - FIELD(unsigned short, type), - FIELD(unsigned char, flags), - FIELD(unsigned char, preempt_count), - FIELD(int, pid), - FIELD(int, lock_depth)); -} - static ssize_t event_format_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct ftrace_event_call *call = filp->private_data; + struct ftrace_event_field *field; struct trace_seq *s; + int common_field_count = 5; char *buf; - int r; + int r = 0; if (*ppos) return 0; @@ -565,14 +548,48 @@ event_format_read(struct file *filp, char __user *ubuf, size_t cnt, trace_seq_init(s); - /* If any of the first writes fail, so will the show_format. */ - trace_seq_printf(s, "name: %s\n", call->name); trace_seq_printf(s, "ID: %d\n", call->id); trace_seq_printf(s, "format:\n"); - trace_write_header(s); - r = call->show_format(call, s); + list_for_each_entry_reverse(field, &call->fields, link) { + /* + * Smartly shows the array type(except dynamic array). + * Normal: + * field:TYPE VAR + * If TYPE := TYPE[LEN], it is shown: + * field:TYPE VAR[LEN] + */ + const char *array_descriptor = strchr(field->type, '['); + + if (!strncmp(field->type, "__data_loc", 10)) + array_descriptor = NULL; + + if (!array_descriptor) { + r = trace_seq_printf(s, "\tfield:%s %s;\toffset:%u;" + "\tsize:%u;\tsigned:%d;\n", + field->type, field->name, field->offset, + field->size, !!field->is_signed); + } else { + r = trace_seq_printf(s, "\tfield:%.*s %s%s;\toffset:%u;" + "\tsize:%u;\tsigned:%d;\n", + (int)(array_descriptor - field->type), + field->type, field->name, + array_descriptor, field->offset, + field->size, !!field->is_signed); + } + + if (--common_field_count == 0) + r = trace_seq_printf(s, "\n"); + + if (!r) + break; + } + + if (r) + r = trace_seq_printf(s, "\nprint fmt: %s\n", + call->print_fmt); + if (!r) { /* * ug! The format output is bigger than a PAGE!! -- cgit v1.2.3 From 0fa0edaf32b9a78b9854f1da98d4511a501089b0 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Dec 2009 15:39:57 +0800 Subject: tracing: Remove show_format and related macros from TRACE_EVENT The previous patches added the use of print_fmt string and changes the trace_define_field() function to also create the fields and format output for the event format files. text data bss dec hex filename 5857201 1355780 9336808 16549789 fc879d vmlinux 5884589 1351684 9337896 16574169 fce6d9 vmlinux-orig The above shows the size of the vmlinux after this patch set compared to the vmlinux-orig which is before the patch set. This saves us 27k on text, 1k on bss and adds just 4k of data. The total savings of 24k in size. Signed-off-by: Lai Jiangshan LKML-Reference: <4B273D4D.40604@cn.fujitsu.com> Acked-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 2 - include/linux/syscalls.h | 2 - include/trace/ftrace.h | 133 ++---------------------------------------- include/trace/syscall.h | 4 -- kernel/trace/trace_events.c | 12 ---- kernel/trace/trace_export.c | 73 ----------------------- kernel/trace/trace_kprobe.c | 78 ------------------------- kernel/trace/trace_syscalls.c | 66 --------------------- 8 files changed, 6 insertions(+), 364 deletions(-) (limited to 'kernel') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index bd23d8e52f02..84a5629adfd8 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -123,8 +123,6 @@ struct ftrace_event_call { int id; const char *print_fmt; int (*raw_init)(struct ftrace_event_call *); - int (*show_format)(struct ftrace_event_call *, - struct trace_seq *); int (*define_fields)(struct ftrace_event_call *); struct list_head fields; int filter_active; diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index ed353d274a77..7b219696ad24 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -144,7 +144,6 @@ struct perf_event_attr; .system = "syscalls", \ .event = &enter_syscall_print_##sname, \ .raw_init = init_syscall_trace, \ - .show_format = syscall_enter_format, \ .define_fields = syscall_enter_define_fields, \ .regfunc = reg_event_syscall_enter, \ .unregfunc = unreg_event_syscall_enter, \ @@ -166,7 +165,6 @@ struct perf_event_attr; .system = "syscalls", \ .event = &exit_syscall_print_##sname, \ .raw_init = init_syscall_trace, \ - .show_format = syscall_exit_format, \ .define_fields = syscall_exit_define_fields, \ .regfunc = reg_event_syscall_exit, \ .unregfunc = unreg_event_syscall_exit, \ diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 3351d85c83a3..df65b99880b1 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -130,130 +130,6 @@ #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) -/* - * Setup the showing format of trace point. - * - * int - * ftrace_format_##call(struct trace_seq *s) - * { - * struct ftrace_raw_##call field; - * int ret; - * - * ret = trace_seq_printf(s, #type " " #item ";" - * " offset:%u; size:%u;\n", - * offsetof(struct ftrace_raw_##call, item), - * sizeof(field.type)); - * - * } - */ - -#undef TP_STRUCT__entry -#define TP_STRUCT__entry(args...) args - -#undef __field -#define __field(type, item) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \ - "offset:%u;\tsize:%u;\tsigned:%u;\n", \ - (unsigned int)offsetof(typeof(field), item), \ - (unsigned int)sizeof(field.item), \ - (unsigned int)is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __field_ext -#define __field_ext(type, item, filter_type) __field(type, item) - -#undef __array -#define __array(type, item, len) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \ - "offset:%u;\tsize:%u;\tsigned:%u;\n", \ - (unsigned int)offsetof(typeof(field), item), \ - (unsigned int)sizeof(field.item), \ - (unsigned int)is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __dynamic_array -#define __dynamic_array(type, item, len) \ - ret = trace_seq_printf(s, "\tfield:__data_loc " #type "[] " #item ";\t"\ - "offset:%u;\tsize:%u;\tsigned:%u;\n", \ - (unsigned int)offsetof(typeof(field), \ - __data_loc_##item), \ - (unsigned int)sizeof(field.__data_loc_##item), \ - (unsigned int)is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __string -#define __string(item, src) __dynamic_array(char, item, -1) - -#undef __entry -#define __entry REC - -#undef __print_symbolic -#undef __get_dynamic_array -#undef __get_str - -#undef TP_printk -#define TP_printk(fmt, args...) "\"%s\", %s\n", fmt, __stringify(args) - -#undef TP_fast_assign -#define TP_fast_assign(args...) args - -#undef TP_perf_assign -#define TP_perf_assign(args...) - -#undef DECLARE_EVENT_CLASS -#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, func, print) \ -static int \ -ftrace_format_setup_##call(struct ftrace_event_call *unused, \ - struct trace_seq *s) \ -{ \ - struct ftrace_raw_##call field __attribute__((unused)); \ - int ret = 0; \ - \ - tstruct; \ - \ - return ret; \ -} \ - \ -static int \ -ftrace_format_##call(struct ftrace_event_call *unused, \ - struct trace_seq *s) \ -{ \ - int ret = 0; \ - \ - ret = ftrace_format_setup_##call(unused, s); \ - if (!ret) \ - return ret; \ - \ - ret = trace_seq_printf(s, "\nprint fmt: " print); \ - \ - return ret; \ -} - -#undef DEFINE_EVENT -#define DEFINE_EVENT(template, name, proto, args) - -#undef DEFINE_EVENT_PRINT -#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ -static int \ -ftrace_format_##name(struct ftrace_event_call *unused, \ - struct trace_seq *s) \ -{ \ - int ret = 0; \ - \ - ret = ftrace_format_setup_##template(unused, s); \ - if (!ret) \ - return ret; \ - \ - trace_seq_printf(s, "\nprint fmt: " print); \ - \ - return ret; \ -} - -#include TRACE_INCLUDE(TRACE_INCLUDE_FILE) - /* * Stage 3 of the trace events. * @@ -622,7 +498,6 @@ static void ftrace_profile_disable_##name(struct ftrace_event_call *unused)\ * .raw_init = trace_event_raw_init, * .regfunc = ftrace_reg_event_, * .unregfunc = ftrace_unreg_event_, - * .show_format = ftrace_format_, * } * */ @@ -657,6 +532,12 @@ static void ftrace_profile_disable_##name(struct ftrace_event_call *unused)\ #define __assign_str(dst, src) \ strcpy(__get_str(dst), src); +#undef TP_fast_assign +#define TP_fast_assign(args...) args + +#undef TP_perf_assign +#define TP_perf_assign(args...) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ \ @@ -750,7 +631,6 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ .regfunc = ftrace_raw_reg_event_##call, \ .unregfunc = ftrace_raw_unreg_event_##call, \ .print_fmt = print_fmt_##template, \ - .show_format = ftrace_format_##template, \ .define_fields = ftrace_define_fields_##template, \ _TRACE_PROFILE_INIT(call) \ } @@ -770,7 +650,6 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ .regfunc = ftrace_raw_reg_event_##call, \ .unregfunc = ftrace_raw_unreg_event_##call, \ .print_fmt = print_fmt_##call, \ - .show_format = ftrace_format_##call, \ .define_fields = ftrace_define_fields_##template, \ _TRACE_PROFILE_INIT(call) \ } diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 961fda3556bb..8cd410254456 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -34,10 +34,6 @@ struct syscall_metadata { extern unsigned long arch_syscall_addr(int nr); extern int init_syscall_trace(struct ftrace_event_call *call); -extern int syscall_enter_format(struct ftrace_event_call *call, - struct trace_seq *s); -extern int syscall_exit_format(struct ftrace_event_call *call, - struct trace_seq *s); extern int syscall_enter_define_fields(struct ftrace_event_call *call); extern int syscall_exit_define_fields(struct ftrace_event_call *call); extern int reg_event_syscall_enter(struct ftrace_event_call *call); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 250ec865d5f5..c2a3077b7353 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -520,14 +520,6 @@ out: return ret; } -extern char *__bad_type_size(void); - -#undef FIELD -#define FIELD(type, name) \ - sizeof(type) != sizeof(field.name) ? __bad_type_size() : \ - #type, "common_" #name, offsetof(typeof(field), name), \ - sizeof(field.name), is_signed_type(type) - static ssize_t event_format_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) @@ -965,10 +957,6 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events, filter); } - /* A trace may not want to export its format */ - if (!call->show_format) - return 0; - trace_create_file("format", 0444, call->dir, call, format); diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 95d14b640a66..e091f64ba6ce 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -62,78 +62,6 @@ static void __always_unused ____ftrace_check_##name(void) \ #include "trace_entries.h" - -#undef __field -#define __field(type, item) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \ - "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \ - offsetof(typeof(field), item), \ - sizeof(field.item), is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __field_desc -#define __field_desc(type, container, item) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \ - "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \ - offsetof(typeof(field), container.item), \ - sizeof(field.container.item), \ - is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __array -#define __array(type, item, len) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \ - "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \ - offsetof(typeof(field), item), \ - sizeof(field.item), is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __array_desc -#define __array_desc(type, container, item, len) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \ - "offset:%zu;\tsize:%zu;\tsigned:%u;\n", \ - offsetof(typeof(field), container.item), \ - sizeof(field.container.item), \ - is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef __dynamic_array -#define __dynamic_array(type, item) \ - ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \ - "offset:%zu;\tsize:0;\tsigned:%u;\n", \ - offsetof(typeof(field), item), \ - is_signed_type(type)); \ - if (!ret) \ - return 0; - -#undef F_printk -#define F_printk(fmt, args...) "%s, %s\n", #fmt, __stringify(args) - -#undef __entry -#define __entry REC - -#undef FTRACE_ENTRY -#define FTRACE_ENTRY(name, struct_name, id, tstruct, print) \ -static int \ -ftrace_format_##name(struct ftrace_event_call *unused, \ - struct trace_seq *s) \ -{ \ - struct struct_name field __attribute__((unused)); \ - int ret = 0; \ - \ - tstruct; \ - \ - trace_seq_printf(s, "\nprint fmt: " print); \ - \ - return ret; \ -} - -#include "trace_entries.h" - #undef __field #define __field(type, item) \ ret = trace_define_field(event_call, #type, #item, \ @@ -235,7 +163,6 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ .system = __stringify(TRACE_SYSTEM), \ .raw_init = ftrace_raw_init_event, \ .print_fmt = print, \ - .show_format = ftrace_format_##call, \ .define_fields = ftrace_define_fields_##call, \ }; \ diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 147491dccead..c99029916c76 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1174,82 +1174,6 @@ static int kretprobe_event_define_fields(struct ftrace_event_call *event_call) return 0; } -static int __probe_event_show_format(struct trace_seq *s, - struct trace_probe *tp, const char *fmt, - const char *arg) -{ - int i; - - /* Show format */ - if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt)) - return 0; - - for (i = 0; i < tp->nr_args; i++) - if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name)) - return 0; - - if (!trace_seq_printf(s, "\", %s", arg)) - return 0; - - for (i = 0; i < tp->nr_args; i++) - if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name)) - return 0; - - return trace_seq_puts(s, "\n"); -} - -#undef SHOW_FIELD -#define SHOW_FIELD(type, item, name) \ - do { \ - ret = trace_seq_printf(s, "\tfield:" #type " %s;\t" \ - "offset:%u;\tsize:%u;\tsigned:%d;\n", name,\ - (unsigned int)offsetof(typeof(field), item),\ - (unsigned int)sizeof(type), \ - is_signed_type(type)); \ - if (!ret) \ - return 0; \ - } while (0) - -static int kprobe_event_show_format(struct ftrace_event_call *call, - struct trace_seq *s) -{ - struct kprobe_trace_entry field __attribute__((unused)); - int ret, i; - struct trace_probe *tp = (struct trace_probe *)call->data; - - SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP); - SHOW_FIELD(int, nargs, FIELD_STRING_NARGS); - - /* Show fields */ - for (i = 0; i < tp->nr_args; i++) - SHOW_FIELD(unsigned long, args[i], tp->args[i].name); - trace_seq_puts(s, "\n"); - - return __probe_event_show_format(s, tp, "(%lx)", - "REC->" FIELD_STRING_IP); -} - -static int kretprobe_event_show_format(struct ftrace_event_call *call, - struct trace_seq *s) -{ - struct kretprobe_trace_entry field __attribute__((unused)); - int ret, i; - struct trace_probe *tp = (struct trace_probe *)call->data; - - SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC); - SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP); - SHOW_FIELD(int, nargs, FIELD_STRING_NARGS); - - /* Show fields */ - for (i = 0; i < tp->nr_args; i++) - SHOW_FIELD(unsigned long, args[i], tp->args[i].name); - trace_seq_puts(s, "\n"); - - return __probe_event_show_format(s, tp, "(%lx <- %lx)", - "REC->" FIELD_STRING_FUNC - ", REC->" FIELD_STRING_RETIP); -} - static int __set_print_fmt(struct trace_probe *tp, char *buf, int len) { int i; @@ -1504,12 +1428,10 @@ static int register_probe_event(struct trace_probe *tp) if (probe_is_return(tp)) { tp->event.trace = print_kretprobe_event; call->raw_init = probe_event_raw_init; - call->show_format = kretprobe_event_show_format; call->define_fields = kretprobe_event_define_fields; } else { tp->event.trace = print_kprobe_event; call->raw_init = probe_event_raw_init; - call->show_format = kprobe_event_show_format; call->define_fields = kprobe_event_define_fields; } if (set_print_fmt(tp) < 0) diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index a78e86349ecb..49cea70fbf6d 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -143,54 +143,6 @@ extern char *__bad_type_size(void); #type, #name, offsetof(typeof(trace), name), \ sizeof(trace.name), is_signed_type(type) -int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s) -{ - int i; - int ret; - struct syscall_metadata *entry = call->data; - struct syscall_trace_enter trace; - int offset = offsetof(struct syscall_trace_enter, args); - - ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;" - "\tsigned:%u;\n", - SYSCALL_FIELD(int, nr)); - if (!ret) - return 0; - - for (i = 0; i < entry->nb_args; i++) { - ret = trace_seq_printf(s, "\tfield:%s %s;", entry->types[i], - entry->args[i]); - if (!ret) - return 0; - ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;" - "\tsigned:%u;\n", offset, - sizeof(unsigned long), - is_signed_type(unsigned long)); - if (!ret) - return 0; - offset += sizeof(unsigned long); - } - - trace_seq_puts(s, "\nprint fmt: \""); - for (i = 0; i < entry->nb_args; i++) { - ret = trace_seq_printf(s, "%s: 0x%%0%zulx%s", entry->args[i], - sizeof(unsigned long), - i == entry->nb_args - 1 ? "" : ", "); - if (!ret) - return 0; - } - trace_seq_putc(s, '"'); - - for (i = 0; i < entry->nb_args; i++) { - ret = trace_seq_printf(s, ", ((unsigned long)(REC->%s))", - entry->args[i]); - if (!ret) - return 0; - } - - return trace_seq_putc(s, '\n'); -} - static int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len) { @@ -252,24 +204,6 @@ static void free_syscall_print_fmt(struct ftrace_event_call *call) kfree(call->print_fmt); } -int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s) -{ - int ret; - struct syscall_trace_exit trace; - - ret = trace_seq_printf(s, - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;" - "\tsigned:%u;\n" - "\tfield:%s %s;\toffset:%zu;\tsize:%zu;" - "\tsigned:%u;\n", - SYSCALL_FIELD(int, nr), - SYSCALL_FIELD(long, ret)); - if (!ret) - return 0; - - return trace_seq_printf(s, "\nprint fmt: \"0x%%lx\", REC->ret\n"); -} - int syscall_enter_define_fields(struct ftrace_event_call *call) { struct syscall_trace_enter trace; -- cgit v1.2.3 From 7e53bd42d14c75192b99674c40fcc359392da59d Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Wed, 6 Jan 2010 20:08:50 +0800 Subject: tracing: Consolidate protection of reader access to the ring buffer At the beginning, access to the ring buffer was fully serialized by trace_types_lock. Patch d7350c3f4569 gives more freedom to readers, and patch b04cc6b1f6 adds code to protect trace_pipe and cpu#/trace_pipe. But actually it is not enough, ring buffer readers are not always read-only, they may consume data. This patch makes accesses to trace, trace_pipe, trace_pipe_raw cpu#/trace, cpu#/trace_pipe and cpu#/trace_pipe_raw serialized. And removes tracing_reader_cpumask which is used to protect trace_pipe. Details: Ring buffer serializes readers, but it is low level protection. The validity of the events (which returns by ring_buffer_peek() ..etc) are not protected by ring buffer. The content of events may become garbage if we allow another process to consume these events concurrently: A) the page of the consumed events may become a normal page (not reader page) in ring buffer, and this page will be rewritten by the events producer. B) The page of the consumed events may become a page for splice_read, and this page will be returned to system. This patch adds trace_access_lock() and trace_access_unlock() primitives. These primitives allow multi process access to different cpu ring buffers concurrently. These primitives don't distinguish read-only and read-consume access. Multi read-only access is also serialized. And we don't use these primitives when we open files, we only use them when we read files. Signed-off-by: Lai Jiangshan LKML-Reference: <4B447D52.1050602@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 136 ++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 97 insertions(+), 39 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0df1b0f2cb9e..abdd333a0825 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include #include @@ -102,9 +103,6 @@ static inline void ftrace_enable_cpu(void) static cpumask_var_t __read_mostly tracing_buffer_mask; -/* Define which cpu buffers are currently read in trace_pipe */ -static cpumask_var_t tracing_reader_cpumask; - #define for_each_tracing_cpu(cpu) \ for_each_cpu(cpu, tracing_buffer_mask) @@ -243,12 +241,91 @@ static struct tracer *current_trace __read_mostly; /* * trace_types_lock is used to protect the trace_types list. - * This lock is also used to keep user access serialized. - * Accesses from userspace will grab this lock while userspace - * activities happen inside the kernel. */ static DEFINE_MUTEX(trace_types_lock); +/* + * serialize the access of the ring buffer + * + * ring buffer serializes readers, but it is low level protection. + * The validity of the events (which returns by ring_buffer_peek() ..etc) + * are not protected by ring buffer. + * + * The content of events may become garbage if we allow other process consumes + * these events concurrently: + * A) the page of the consumed events may become a normal page + * (not reader page) in ring buffer, and this page will be rewrited + * by events producer. + * B) The page of the consumed events may become a page for splice_read, + * and this page will be returned to system. + * + * These primitives allow multi process access to different cpu ring buffer + * concurrently. + * + * These primitives don't distinguish read-only and read-consume access. + * Multi read-only access are also serialized. + */ + +#ifdef CONFIG_SMP +static DECLARE_RWSEM(all_cpu_access_lock); +static DEFINE_PER_CPU(struct mutex, cpu_access_lock); + +static inline void trace_access_lock(int cpu) +{ + if (cpu == TRACE_PIPE_ALL_CPU) { + /* gain it for accessing the whole ring buffer. */ + down_write(&all_cpu_access_lock); + } else { + /* gain it for accessing a cpu ring buffer. */ + + /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */ + down_read(&all_cpu_access_lock); + + /* Secondly block other access to this @cpu ring buffer. */ + mutex_lock(&per_cpu(cpu_access_lock, cpu)); + } +} + +static inline void trace_access_unlock(int cpu) +{ + if (cpu == TRACE_PIPE_ALL_CPU) { + up_write(&all_cpu_access_lock); + } else { + mutex_unlock(&per_cpu(cpu_access_lock, cpu)); + up_read(&all_cpu_access_lock); + } +} + +static inline void trace_access_lock_init(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + mutex_init(&per_cpu(cpu_access_lock, cpu)); +} + +#else + +static DEFINE_MUTEX(access_lock); + +static inline void trace_access_lock(int cpu) +{ + (void)cpu; + mutex_lock(&access_lock); +} + +static inline void trace_access_unlock(int cpu) +{ + (void)cpu; + mutex_unlock(&access_lock); +} + +static inline void trace_access_lock_init(void) +{ +} + +#endif + /* trace_wait is a waitqueue for tasks blocked on trace_poll */ static DECLARE_WAIT_QUEUE_HEAD(trace_wait); @@ -1580,12 +1657,6 @@ static void tracing_iter_reset(struct trace_iterator *iter, int cpu) } /* - * No necessary locking here. The worst thing which can - * happen is loosing events consumed at the same time - * by a trace_pipe reader. - * Other than that, we don't risk to crash the ring buffer - * because it serializes the readers. - * * The current tracer is copied to avoid a global locking * all around. */ @@ -1640,12 +1711,16 @@ static void *s_start(struct seq_file *m, loff_t *pos) } trace_event_read_lock(); + trace_access_lock(cpu_file); return p; } static void s_stop(struct seq_file *m, void *p) { + struct trace_iterator *iter = m->private; + atomic_dec(&trace_record_cmdline_disabled); + trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); } @@ -2836,22 +2911,6 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) mutex_lock(&trace_types_lock); - /* We only allow one reader per cpu */ - if (cpu_file == TRACE_PIPE_ALL_CPU) { - if (!cpumask_empty(tracing_reader_cpumask)) { - ret = -EBUSY; - goto out; - } - cpumask_setall(tracing_reader_cpumask); - } else { - if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask)) - cpumask_set_cpu(cpu_file, tracing_reader_cpumask); - else { - ret = -EBUSY; - goto out; - } - } - /* create a buffer to store the information to pass to userspace */ iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) { @@ -2907,12 +2966,6 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) mutex_lock(&trace_types_lock); - if (iter->cpu_file == TRACE_PIPE_ALL_CPU) - cpumask_clear(tracing_reader_cpumask); - else - cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask); - - if (iter->trace->pipe_close) iter->trace->pipe_close(iter); @@ -3074,6 +3127,7 @@ waitagain: iter->pos = -1; trace_event_read_lock(); + trace_access_lock(iter->cpu_file); while (find_next_entry_inc(iter) != NULL) { enum print_line_t ret; int len = iter->seq.len; @@ -3090,6 +3144,7 @@ waitagain: if (iter->seq.len >= cnt) break; } + trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); /* Now copy what we have to the user */ @@ -3215,6 +3270,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp, } trace_event_read_lock(); + trace_access_lock(iter->cpu_file); /* Fill as many pages as possible. */ for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) { @@ -3238,6 +3294,7 @@ static ssize_t tracing_splice_read_pipe(struct file *filp, trace_seq_init(&iter->seq); } + trace_access_unlock(iter->cpu_file); trace_event_read_unlock(); mutex_unlock(&iter->mutex); @@ -3539,10 +3596,12 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, info->read = 0; + trace_access_lock(info->cpu); ret = ring_buffer_read_page(info->tr->buffer, &info->spare, count, info->cpu, 0); + trace_access_unlock(info->cpu); if (ret < 0) return 0; @@ -3670,6 +3729,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, len &= PAGE_MASK; } + trace_access_lock(info->cpu); entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu); for (i = 0; i < PIPE_BUFFERS && len && entries; i++, len -= PAGE_SIZE) { @@ -3717,6 +3777,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu); } + trace_access_unlock(info->cpu); spd.nr_pages = i; /* did we read anything? */ @@ -4153,6 +4214,8 @@ static __init int tracer_init_debugfs(void) struct dentry *d_tracer; int cpu; + trace_access_lock_init(); + d_tracer = tracing_init_dentry(); trace_create_file("tracing_enabled", 0644, d_tracer, @@ -4387,9 +4450,6 @@ __init static int tracer_alloc_buffers(void) if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL)) goto out_free_buffer_mask; - if (!zalloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL)) - goto out_free_tracing_cpumask; - /* To save memory, keep the ring buffer size to its minimum */ if (ring_buffer_expanded) ring_buf_size = trace_buf_size; @@ -4447,8 +4507,6 @@ __init static int tracer_alloc_buffers(void) return 0; out_free_cpumask: - free_cpumask_var(tracing_reader_cpumask); -out_free_tracing_cpumask: free_cpumask_var(tracing_cpumask); out_free_buffer_mask: free_cpumask_var(tracing_buffer_mask); -- cgit v1.2.3 From d931369b74b3d6f2044f595af6f3dd074f65d9cf Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 6 Jan 2010 17:27:11 -0500 Subject: tracing: Add stack dump to trace_printk if stacktrace option is set If the ftrace stacktrace option is set, then add the stack dumps to trace_printk. Requested-by: Peter Zijlstra Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index abdd333a0825..5314c90bbc83 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1392,8 +1392,10 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) entry->fmt = fmt; memcpy(entry->buf, trace_buf, sizeof(u32) * len); - if (!filter_check_discard(call, entry, buffer, event)) + if (!filter_check_discard(call, entry, buffer, event)) { ring_buffer_unlock_commit(buffer, event); + ftrace_trace_stack(buffer, flags, 6, pc); + } out_unlock: arch_spin_unlock(&trace_buf_lock); @@ -1466,8 +1468,10 @@ int trace_array_vprintk(struct trace_array *tr, memcpy(&entry->buf, trace_buf, len); entry->buf[len] = '\0'; - if (!filter_check_discard(call, entry, buffer, event)) + if (!filter_check_discard(call, entry, buffer, event)) { ring_buffer_unlock_commit(buffer, event); + ftrace_trace_stack(buffer, irq_flags, 6, pc); + } out_unlock: arch_spin_unlock(&trace_buf_lock); -- cgit v1.2.3 From f96e9232e04856c781d4f71923a46dd3f7b429fa Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:00 -0800 Subject: rcu: Adjust force_quiescent_state() locking, step 1 This causes rnp->lock to be held on entry to force_quiescent_state()'s switch statement. This is a first step towards prohibiting starting grace periods while force_quiescent_state() is executing, which will reduce the number and complexity of races that force_quiescent_state() is involved in. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465501455-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 53ae9598f798..eae331da6bee 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1204,7 +1204,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) } if (relaxed && (long)(rsp->jiffies_force_qs - jiffies) >= 0) - goto unlock_ret; /* no emergency and done recently. */ + goto unlock_fqs_ret; /* no emergency and done recently. */ rsp->n_force_qs++; spin_lock(&rnp->lock); lastcomp = rsp->gpnum - 1; @@ -1213,31 +1213,32 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; spin_unlock(&rnp->lock); - goto unlock_ret; /* no GP in progress, time updated. */ + goto unlock_fqs_ret; /* no GP in progress, time updated. */ } - spin_unlock(&rnp->lock); switch (signaled) { case RCU_GP_IDLE: case RCU_GP_INIT: + spin_unlock(&rnp->lock); break; /* grace period idle or initializing, ignore. */ case RCU_SAVE_DYNTICK: + spin_unlock(&rnp->lock); if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ if (rcu_process_dyntick(rsp, lastcomp, dyntick_save_progress_counter)) - goto unlock_ret; + goto unlock_fqs_ret; + spin_lock(&rnp->lock); /* fall into next case. */ case RCU_SAVE_COMPLETED: /* Update state, record completion counter. */ forcenow = 0; - spin_lock(&rnp->lock); if (lastcomp + 1 == rsp->gpnum && lastcomp == rsp->completed && rsp->signaled == signaled) { @@ -1245,23 +1246,31 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) rsp->completed_fqs = lastcomp; forcenow = signaled == RCU_SAVE_COMPLETED; } - spin_unlock(&rnp->lock); - if (!forcenow) + if (!forcenow) { + spin_unlock(&rnp->lock); break; + } /* fall into next case. */ case RCU_FORCE_QS: /* Check dyntick-idle state, send IPI to laggarts. */ + spin_unlock(&rnp->lock); if (rcu_process_dyntick(rsp, rsp->completed_fqs, rcu_implicit_dynticks_qs)) - goto unlock_ret; + goto unlock_fqs_ret; /* Leave state in case more forcing is required. */ break; + + default: + + spin_unlock(&rnp->lock); + WARN_ON_ONCE(1); + break; } -unlock_ret: +unlock_fqs_ret: spin_unlock_irqrestore(&rsp->fqslock, flags); } -- cgit v1.2.3 From 559569acf94f538b56bd6eead80b439d6a78cdff Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:01 -0800 Subject: rcu: Adjust force_quiescent_state() locking, step 2 This patch releases rnp->lock after the end of force_quiescent_state()'s switch statement. This is a second step towards prohibiting starting grace periods while force_quiescent_state() is executing, which will reduce the number and complexity of races that force_quiescent_state() is involved in. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465501994-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index eae331da6bee..d42ad30c4d70 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1219,7 +1219,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_GP_IDLE: case RCU_GP_INIT: - spin_unlock(&rnp->lock); break; /* grace period idle or initializing, ignore. */ case RCU_SAVE_DYNTICK: @@ -1246,10 +1245,8 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) rsp->completed_fqs = lastcomp; forcenow = signaled == RCU_SAVE_COMPLETED; } - if (!forcenow) { - spin_unlock(&rnp->lock); + if (!forcenow) break; - } /* fall into next case. */ case RCU_FORCE_QS: @@ -1262,14 +1259,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Leave state in case more forcing is required. */ - break; - - default: - - spin_unlock(&rnp->lock); - WARN_ON_ONCE(1); + spin_lock(&rnp->lock); break; } + spin_unlock(&rnp->lock); unlock_fqs_ret: spin_unlock_irqrestore(&rsp->fqslock, flags); } -- cgit v1.2.3 From 07079d5357a4d53c2b13126c4a38fb40e6e04966 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:02 -0800 Subject: rcu: Prohibit starting new grace periods while forcing quiescent states Reduce the number and variety of race conditions by prohibiting the start of a new grace period while force_quiescent_state() is active. A new fqs_active flag in the rcu_state structure is used to trace whether or not force_quiescent_state() is active, and this new flag is tested by rcu_start_gp(). If the CPU that closed out the last grace period needs another grace period, this new grace period may be delayed up to one scheduling-clock tick, but it will eventually get started. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <126264655052-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 31 +++++++++++++++++-------------- kernel/rcutree.h | 2 ++ 2 files changed, 19 insertions(+), 14 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index d42ad30c4d70..41688ff60e07 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -659,7 +659,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) struct rcu_data *rdp = rsp->rda[smp_processor_id()]; struct rcu_node *rnp = rcu_get_root(rsp); - if (!cpu_needs_another_gp(rsp, rdp)) { + if (!cpu_needs_another_gp(rsp, rdp) || rsp->fqs_active) { if (rnp->completed == rsp->completed) { spin_unlock_irqrestore(&rnp->lock, flags); return; @@ -1195,6 +1195,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) struct rcu_node *rnp = rcu_get_root(rsp); u8 signaled; u8 forcenow; + u8 gpdone; if (!rcu_gp_in_progress(rsp)) return; /* No grace period in progress, nothing to force. */ @@ -1206,15 +1207,16 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) (long)(rsp->jiffies_force_qs - jiffies) >= 0) goto unlock_fqs_ret; /* no emergency and done recently. */ rsp->n_force_qs++; - spin_lock(&rnp->lock); + spin_lock(&rnp->lock); /* irqs already disabled */ lastcomp = rsp->gpnum - 1; signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; - spin_unlock(&rnp->lock); + spin_unlock(&rnp->lock); /* irqs remain disabled */ goto unlock_fqs_ret; /* no GP in progress, time updated. */ } + rsp->fqs_active = 1; switch (signaled) { case RCU_GP_IDLE: case RCU_GP_INIT: @@ -1223,15 +1225,16 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_SAVE_DYNTICK: - spin_unlock(&rnp->lock); + spin_unlock(&rnp->lock); /* irqs remain disabled */ if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ - if (rcu_process_dyntick(rsp, lastcomp, - dyntick_save_progress_counter)) - goto unlock_fqs_ret; - spin_lock(&rnp->lock); + gpdone = rcu_process_dyntick(rsp, lastcomp, + dyntick_save_progress_counter); + spin_lock(&rnp->lock); /* irqs already disabled */ + if (gpdone) + break; /* fall into next case. */ case RCU_SAVE_COMPLETED: @@ -1252,17 +1255,17 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_FORCE_QS: /* Check dyntick-idle state, send IPI to laggarts. */ - spin_unlock(&rnp->lock); - if (rcu_process_dyntick(rsp, rsp->completed_fqs, - rcu_implicit_dynticks_qs)) - goto unlock_fqs_ret; + spin_unlock(&rnp->lock); /* irqs remain disabled */ + gpdone = rcu_process_dyntick(rsp, rsp->completed_fqs, + rcu_implicit_dynticks_qs); /* Leave state in case more forcing is required. */ - spin_lock(&rnp->lock); + spin_lock(&rnp->lock); /* irqs already disabled */ break; } - spin_unlock(&rnp->lock); + rsp->fqs_active = 0; + spin_unlock(&rnp->lock); /* irqs remain disabled */ unlock_fqs_ret: spin_unlock_irqrestore(&rsp->fqslock, flags); } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index d2a0046f63b2..dc386a7c634f 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -277,6 +277,8 @@ struct rcu_state { u8 signaled ____cacheline_internodealigned_in_smp; /* Force QS state. */ + u8 fqs_active; /* force_quiescent_state() */ + /* is running. */ long gpnum; /* Current gp number. */ long completed; /* # of last completed gp. */ -- cgit v1.2.3 From f3a8b5c6aa543bd87764418d63632eb65b80e2f6 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:03 -0800 Subject: rcu: Eliminate local variable signaled from force_quiescent_state() Because the root rcu_node lock is held across entry to the switch statement in force_quiescent_state(), it is no longer necessary to snapshot rsp->signaled to a local variable. Eliminate both the snapshotting and the local variable. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1262646550602-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 41688ff60e07..1d8cfb1711fd 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1193,7 +1193,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) unsigned long flags; long lastcomp; struct rcu_node *rnp = rcu_get_root(rsp); - u8 signaled; u8 forcenow; u8 gpdone; @@ -1209,7 +1208,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) rsp->n_force_qs++; spin_lock(&rnp->lock); /* irqs already disabled */ lastcomp = rsp->gpnum - 1; - signaled = rsp->signaled; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; @@ -1217,7 +1215,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) goto unlock_fqs_ret; /* no GP in progress, time updated. */ } rsp->fqs_active = 1; - switch (signaled) { + switch (rsp->signaled) { case RCU_GP_IDLE: case RCU_GP_INIT: @@ -1242,11 +1240,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Update state, record completion counter. */ forcenow = 0; if (lastcomp + 1 == rsp->gpnum && - lastcomp == rsp->completed && - rsp->signaled == signaled) { + lastcomp == rsp->completed) { + forcenow = rsp->signaled == RCU_SAVE_COMPLETED; rsp->signaled = RCU_FORCE_QS; rsp->completed_fqs = lastcomp; - forcenow = signaled == RCU_SAVE_COMPLETED; } if (!forcenow) break; -- cgit v1.2.3 From 39c0bbfc07c6e28db7346d0e11106f2d045d3035 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:04 -0800 Subject: rcu: Eliminate local variable lastcomp from force_quiescent_state() Because rsp->fqs_active is set to 1 across force_quiescent_state()'s switch statement, rcu_start_gp() will refrain from starting a new grace period during this time. Therefore, rsp->gpnum is constant, and can be propagated to all uses of lastcomp, eliminating this local variable. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465502985-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 10 +++------- kernel/rcutree.h | 2 -- 2 files changed, 3 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 1d8cfb1711fd..62b64332effb 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1191,7 +1191,6 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, static void force_quiescent_state(struct rcu_state *rsp, int relaxed) { unsigned long flags; - long lastcomp; struct rcu_node *rnp = rcu_get_root(rsp); u8 forcenow; u8 gpdone; @@ -1207,7 +1206,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) goto unlock_fqs_ret; /* no emergency and done recently. */ rsp->n_force_qs++; spin_lock(&rnp->lock); /* irqs already disabled */ - lastcomp = rsp->gpnum - 1; rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; @@ -1228,7 +1226,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ - gpdone = rcu_process_dyntick(rsp, lastcomp, + gpdone = rcu_process_dyntick(rsp, rsp->gpnum - 1, dyntick_save_progress_counter); spin_lock(&rnp->lock); /* irqs already disabled */ if (gpdone) @@ -1239,11 +1237,9 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Update state, record completion counter. */ forcenow = 0; - if (lastcomp + 1 == rsp->gpnum && - lastcomp == rsp->completed) { + if (rsp->gpnum - 1 == rsp->completed) { forcenow = rsp->signaled == RCU_SAVE_COMPLETED; rsp->signaled = RCU_FORCE_QS; - rsp->completed_fqs = lastcomp; } if (!forcenow) break; @@ -1253,7 +1249,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Check dyntick-idle state, send IPI to laggarts. */ spin_unlock(&rnp->lock); /* irqs remain disabled */ - gpdone = rcu_process_dyntick(rsp, rsp->completed_fqs, + gpdone = rcu_process_dyntick(rsp, rsp->gpnum - 1, rcu_implicit_dynticks_qs); /* Leave state in case more forcing is required. */ diff --git a/kernel/rcutree.h b/kernel/rcutree.h index dc386a7c634f..534856121b06 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -296,8 +296,6 @@ struct rcu_state { long orphan_qlen; /* Number of orphaned cbs. */ spinlock_t fqslock; /* Only one task forcing */ /* quiescent states. */ - long completed_fqs; /* Value of completed @ snap. */ - /* Protected by fqslock. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */ unsigned long n_force_qs; /* Number of calls to */ -- cgit v1.2.3 From eb1ba45f1e7f6e626fefc063b340c7cbec9bd8c7 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:05 -0800 Subject: rcu: Eliminate second argument of rcu_process_dyntick() At this point, the second argument to all calls to rcu_process_dyntick() is a function of the same field of the structure passed in as the first argument, namely, rsp->gpnum-1. So propagate rsp->gpnum-1 to all uses of the second argument within rcu_process_dyntick() and then eliminate the second argument. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465503786-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 62b64332effb..c7d00700fc4e 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1147,7 +1147,7 @@ void rcu_check_callbacks(int cpu, int user) * Returns 1 if the current grace period ends while scanning (possibly * because we made it end). */ -static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, +static int rcu_process_dyntick(struct rcu_state *rsp, int (*f)(struct rcu_data *)) { unsigned long bit; @@ -1159,7 +1159,7 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, rcu_for_each_leaf_node(rsp, rnp) { mask = 0; spin_lock_irqsave(&rnp->lock, flags); - if (rnp->completed != lastcomp) { + if (rnp->completed != rsp->gpnum - 1) { spin_unlock_irqrestore(&rnp->lock, flags); return 1; } @@ -1173,7 +1173,7 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu])) mask |= bit; } - if (mask != 0 && rnp->completed == lastcomp) { + if (mask != 0 && rnp->completed == rsp->gpnum - 1) { /* rcu_report_qs_rnp() releases rnp->lock. */ rcu_report_qs_rnp(mask, rsp, rnp, flags); @@ -1226,7 +1226,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ - gpdone = rcu_process_dyntick(rsp, rsp->gpnum - 1, + gpdone = rcu_process_dyntick(rsp, dyntick_save_progress_counter); spin_lock(&rnp->lock); /* irqs already disabled */ if (gpdone) @@ -1249,8 +1249,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Check dyntick-idle state, send IPI to laggarts. */ spin_unlock(&rnp->lock); /* irqs remain disabled */ - gpdone = rcu_process_dyntick(rsp, rsp->gpnum - 1, - rcu_implicit_dynticks_qs); + gpdone = rcu_process_dyntick(rsp, rcu_implicit_dynticks_qs); /* Leave state in case more forcing is required. */ -- cgit v1.2.3 From 0f10dc826646134dce3e5751512b87d30f3903e4 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:06 -0800 Subject: rcu: Eliminate rcu_process_dyntick() return value Because a new grace period cannot start while we are executing within the force_quiescent_state() function's switch statement, if any test within that switch statement or within any function called from that switch statement shows that the current grace period has ended, we can safely re-do that test any time before we leave the switch statement. This means that we no longer need a return value from rcu_process_dyntick(), as we can simply invoke rcu_gp_in_progress() to check whether the old grace period has finished -- there is no longer any need to worry about whether or not a new grace period has been started. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465501857-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index c7d00700fc4e..e4971192fa9c 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1144,11 +1144,9 @@ void rcu_check_callbacks(int cpu, int user) /* * Scan the leaf rcu_node structures, processing dyntick state for any that * have not yet encountered a quiescent state, using the function specified. - * Returns 1 if the current grace period ends while scanning (possibly - * because we made it end). */ -static int rcu_process_dyntick(struct rcu_state *rsp, - int (*f)(struct rcu_data *)) +static void rcu_process_dyntick(struct rcu_state *rsp, + int (*f)(struct rcu_data *)) { unsigned long bit; int cpu; @@ -1161,7 +1159,7 @@ static int rcu_process_dyntick(struct rcu_state *rsp, spin_lock_irqsave(&rnp->lock, flags); if (rnp->completed != rsp->gpnum - 1) { spin_unlock_irqrestore(&rnp->lock, flags); - return 1; + return; } if (rnp->qsmask == 0) { spin_unlock_irqrestore(&rnp->lock, flags); @@ -1181,7 +1179,6 @@ static int rcu_process_dyntick(struct rcu_state *rsp, } spin_unlock_irqrestore(&rnp->lock, flags); } - return 0; } /* @@ -1193,7 +1190,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) unsigned long flags; struct rcu_node *rnp = rcu_get_root(rsp); u8 forcenow; - u8 gpdone; if (!rcu_gp_in_progress(rsp)) return; /* No grace period in progress, nothing to force. */ @@ -1226,10 +1222,9 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ - gpdone = rcu_process_dyntick(rsp, - dyntick_save_progress_counter); + rcu_process_dyntick(rsp, dyntick_save_progress_counter); spin_lock(&rnp->lock); /* irqs already disabled */ - if (gpdone) + if (!rcu_gp_in_progress(rsp)) break; /* fall into next case. */ @@ -1249,7 +1244,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Check dyntick-idle state, send IPI to laggarts. */ spin_unlock(&rnp->lock); /* irqs remain disabled */ - gpdone = rcu_process_dyntick(rsp, rcu_implicit_dynticks_qs); + rcu_process_dyntick(rsp, rcu_implicit_dynticks_qs); /* Leave state in case more forcing is required. */ -- cgit v1.2.3 From ee47eb9f4da6f44af965d6d049e77ee8c8a4b822 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:07 -0800 Subject: rcu: Remove leg of force_quiescent_state() switch statement The comparisons of rsp->gpnum nad rsp->completed in rcu_process_dyntick() and force_quiescent_state() can be replaced by the much more clear rcu_gp_in_progress() predicate function. After doing this, it becomes clear that the RCU_SAVE_COMPLETED leg of the force_quiescent_state() function's switch statement is almost completely a no-op. A small change to the RCU_SAVE_DYNTICK leg renders it a complete no-op, after which it can be removed. Doing so also eliminates the forcenow local variable from force_quiescent_state(). Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465501781-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 22 +++++----------------- kernel/rcutree.h | 5 ++--- 2 files changed, 7 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index e4971192fa9c..6268f37adfc4 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1144,6 +1144,7 @@ void rcu_check_callbacks(int cpu, int user) /* * Scan the leaf rcu_node structures, processing dyntick state for any that * have not yet encountered a quiescent state, using the function specified. + * The caller must have suppressed start of new grace periods. */ static void rcu_process_dyntick(struct rcu_state *rsp, int (*f)(struct rcu_data *)) @@ -1157,7 +1158,7 @@ static void rcu_process_dyntick(struct rcu_state *rsp, rcu_for_each_leaf_node(rsp, rnp) { mask = 0; spin_lock_irqsave(&rnp->lock, flags); - if (rnp->completed != rsp->gpnum - 1) { + if (!rcu_gp_in_progress(rsp)) { spin_unlock_irqrestore(&rnp->lock, flags); return; } @@ -1171,7 +1172,7 @@ static void rcu_process_dyntick(struct rcu_state *rsp, if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu])) mask |= bit; } - if (mask != 0 && rnp->completed == rsp->gpnum - 1) { + if (mask != 0 && rcu_gp_in_progress(rsp)) { /* rcu_report_qs_rnp() releases rnp->lock. */ rcu_report_qs_rnp(mask, rsp, rnp, flags); @@ -1189,7 +1190,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) { unsigned long flags; struct rcu_node *rnp = rcu_get_root(rsp); - u8 forcenow; if (!rcu_gp_in_progress(rsp)) return; /* No grace period in progress, nothing to force. */ @@ -1224,21 +1224,9 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Record dyntick-idle state. */ rcu_process_dyntick(rsp, dyntick_save_progress_counter); spin_lock(&rnp->lock); /* irqs already disabled */ - if (!rcu_gp_in_progress(rsp)) - break; - /* fall into next case. */ - - case RCU_SAVE_COMPLETED: - - /* Update state, record completion counter. */ - forcenow = 0; - if (rsp->gpnum - 1 == rsp->completed) { - forcenow = rsp->signaled == RCU_SAVE_COMPLETED; + if (rcu_gp_in_progress(rsp)) rsp->signaled = RCU_FORCE_QS; - } - if (!forcenow) - break; - /* fall into next case. */ + break; case RCU_FORCE_QS: diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 534856121b06..edb6fae0fa94 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -237,12 +237,11 @@ struct rcu_data { #define RCU_GP_IDLE 0 /* No grace period in progress. */ #define RCU_GP_INIT 1 /* Grace period being initialized. */ #define RCU_SAVE_DYNTICK 2 /* Need to scan dyntick state. */ -#define RCU_SAVE_COMPLETED 3 /* Need to save rsp->completed. */ -#define RCU_FORCE_QS 4 /* Need to force quiescent state. */ +#define RCU_FORCE_QS 3 /* Need to force quiescent state. */ #ifdef CONFIG_NO_HZ #define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK #else /* #ifdef CONFIG_NO_HZ */ -#define RCU_SIGNAL_INIT RCU_SAVE_COMPLETED +#define RCU_SIGNAL_INIT RCU_FORCE_QS #endif /* #else #ifdef CONFIG_NO_HZ */ #define RCU_JIFFIES_TILL_FORCE_QS 3 /* for rsp->jiffies_force_qs */ -- cgit v1.2.3 From 45f014c52eef022873b19d6a20eb0ec9668f2b09 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:08 -0800 Subject: rcu: Remove redundant grace-period check The rcu_process_dyntick() function checks twice for the end of the current grace period. However, it holds the current rcu_node structure's ->lock field throughout, and doesn't get to the second call to rcu_gp_in_progress() unless there is at least one CPU corresponding to this rcu_node structure that has not yet checked in for the current grace period, which would prevent the current grace period from ending. So the current grace period cannot have ended, and the second check is redundant, so remove it. Also, given that this function is used even with !CONFIG_NO_HZ, its name is quite misleading. Change from rcu_process_dyntick() to force_qs_rnp(). Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1262646550562-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 6268f37adfc4..d9202857d3ad 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1146,8 +1146,7 @@ void rcu_check_callbacks(int cpu, int user) * have not yet encountered a quiescent state, using the function specified. * The caller must have suppressed start of new grace periods. */ -static void rcu_process_dyntick(struct rcu_state *rsp, - int (*f)(struct rcu_data *)) +static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) { unsigned long bit; int cpu; @@ -1172,7 +1171,7 @@ static void rcu_process_dyntick(struct rcu_state *rsp, if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu])) mask |= bit; } - if (mask != 0 && rcu_gp_in_progress(rsp)) { + if (mask != 0) { /* rcu_report_qs_rnp() releases rnp->lock. */ rcu_report_qs_rnp(mask, rsp, rnp, flags); @@ -1222,7 +1221,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ - rcu_process_dyntick(rsp, dyntick_save_progress_counter); + force_qs_rnp(rsp, dyntick_save_progress_counter); spin_lock(&rnp->lock); /* irqs already disabled */ if (rcu_gp_in_progress(rsp)) rsp->signaled = RCU_FORCE_QS; @@ -1232,7 +1231,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) /* Check dyntick-idle state, send IPI to laggarts. */ spin_unlock(&rnp->lock); /* irqs remain disabled */ - rcu_process_dyntick(rsp, rcu_implicit_dynticks_qs); + force_qs_rnp(rsp, rcu_implicit_dynticks_qs); /* Leave state in case more forcing is required. */ -- cgit v1.2.3 From 46a1e34eda805501a8b32f26394faa435149f6d1 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:09 -0800 Subject: rcu: Make force_quiescent_state() start grace period if needed Grace periods cannot be started while force_quiescent_state() is active. This is OK in that the affected CPUs will try again later, but it does induce needless grace-period delays. This patch causes rcu_start_gp() to record a failed attempt to start a grace period. When force_quiescent_state() prepares to return, it then starts the grace period if there was such a failed attempt. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626465501854-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 8 ++++++++ kernel/rcutree.h | 5 +++++ 2 files changed, 13 insertions(+) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index d9202857d3ad..55e8f6ef8195 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -660,6 +660,8 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) struct rcu_node *rnp = rcu_get_root(rsp); if (!cpu_needs_another_gp(rsp, rdp) || rsp->fqs_active) { + if (cpu_needs_another_gp(rsp, rdp)) + rsp->fqs_need_gp = 1; if (rnp->completed == rsp->completed) { spin_unlock_irqrestore(&rnp->lock, flags); return; @@ -1239,6 +1241,12 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) break; } rsp->fqs_active = 0; + if (rsp->fqs_need_gp) { + spin_unlock(&rsp->fqslock); /* irqs remain disabled */ + rsp->fqs_need_gp = 0; + rcu_start_gp(rsp, flags); /* releases rnp->lock */ + return; + } spin_unlock(&rnp->lock); /* irqs remain disabled */ unlock_fqs_ret: spin_unlock_irqrestore(&rsp->fqslock, flags); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index edb6fae0fa94..bd5d78ad1c48 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -278,6 +278,11 @@ struct rcu_state { /* Force QS state. */ u8 fqs_active; /* force_quiescent_state() */ /* is running. */ + u8 fqs_need_gp; /* A CPU was prevented from */ + /* starting a new grace */ + /* period because */ + /* force_quiescent_state() */ + /* was running. */ long gpnum; /* Current gp number. */ long completed; /* # of last completed gp. */ -- cgit v1.2.3 From bf66f18e79e34c421bbd8f6511e2c556b779df2f Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 15:09:10 -0800 Subject: rcu: Add force_quiescent_state() testing to rcutorture Add force_quiescent_state() testing to rcutorture, with a separate thread that repeatedly invokes force_quiescent_state() in bursts. This can greatly increase the probability of encountering certain types of race conditions. Suggested-by: Josh Triplett Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1262646551116-git-send-email-> Signed-off-by: Ingo Molnar --- include/linux/rcutiny.h | 12 ++++++++ include/linux/rcutree.h | 3 ++ kernel/rcutorture.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++-- kernel/rcutree.c | 18 +++++++++++ kernel/rcutree_plugin.h | 19 ++++++++++++ 5 files changed, 130 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 96cc307ed9f4..2b70d4e37383 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -62,6 +62,18 @@ static inline long rcu_batches_completed_bh(void) extern int rcu_expedited_torture_stats(char *page); +static inline void rcu_force_quiescent_state(void) +{ +} + +static inline void rcu_bh_force_quiescent_state(void) +{ +} + +static inline void rcu_sched_force_quiescent_state(void) +{ +} + #define synchronize_rcu synchronize_sched static inline void synchronize_rcu_expedited(void) diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 8044b1b94333..704a010f686c 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -99,6 +99,9 @@ extern void rcu_check_callbacks(int cpu, int user); extern long rcu_batches_completed(void); extern long rcu_batches_completed_bh(void); extern long rcu_batches_completed_sched(void); +extern void rcu_force_quiescent_state(void); +extern void rcu_bh_force_quiescent_state(void); +extern void rcu_sched_force_quiescent_state(void); #ifdef CONFIG_NO_HZ void rcu_enter_nohz(void); diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 9bb52177af02..adda92bfafac 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -61,6 +61,9 @@ static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */ static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/ static int stutter = 5; /* Start/stop testing interval (in sec) */ static int irqreader = 1; /* RCU readers from irq (timers). */ +static int fqs_duration = 0; /* Duration of bursts (us), 0 to disable. */ +static int fqs_holdoff = 0; /* Hold time within burst (us). */ +static int fqs_stutter = 3; /* Wait time between bursts (s). */ static char *torture_type = "rcu"; /* What RCU implementation to torture. */ module_param(nreaders, int, 0444); @@ -79,6 +82,12 @@ module_param(stutter, int, 0444); MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test"); module_param(irqreader, int, 0444); MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers"); +module_param(fqs_duration, int, 0444); +MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)"); +module_param(fqs_holdoff, int, 0444); +MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)"); +module_param(fqs_stutter, int, 0444); +MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)"); module_param(torture_type, charp, 0444); MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)"); @@ -99,6 +108,7 @@ static struct task_struct **reader_tasks; static struct task_struct *stats_task; static struct task_struct *shuffler_task; static struct task_struct *stutter_task; +static struct task_struct *fqs_task; #define RCU_TORTURE_PIPE_LEN 10 @@ -263,6 +273,7 @@ struct rcu_torture_ops { void (*deferred_free)(struct rcu_torture *p); void (*sync)(void); void (*cb_barrier)(void); + void (*fqs)(void); int (*stats)(char *page); int irq_capable; char *name; @@ -347,6 +358,7 @@ static struct rcu_torture_ops rcu_ops = { .deferred_free = rcu_torture_deferred_free, .sync = synchronize_rcu, .cb_barrier = rcu_barrier, + .fqs = rcu_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu" @@ -388,6 +400,7 @@ static struct rcu_torture_ops rcu_sync_ops = { .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu, .cb_barrier = NULL, + .fqs = rcu_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_sync" @@ -403,6 +416,7 @@ static struct rcu_torture_ops rcu_expedited_ops = { .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_rcu_expedited, .cb_barrier = NULL, + .fqs = rcu_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_expedited" @@ -465,6 +479,7 @@ static struct rcu_torture_ops rcu_bh_ops = { .deferred_free = rcu_bh_torture_deferred_free, .sync = rcu_bh_torture_synchronize, .cb_barrier = rcu_barrier_bh, + .fqs = rcu_bh_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_bh" @@ -480,6 +495,7 @@ static struct rcu_torture_ops rcu_bh_sync_ops = { .deferred_free = rcu_sync_torture_deferred_free, .sync = rcu_bh_torture_synchronize, .cb_barrier = NULL, + .fqs = rcu_bh_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "rcu_bh_sync" @@ -621,6 +637,7 @@ static struct rcu_torture_ops sched_ops = { .deferred_free = rcu_sched_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = rcu_barrier_sched, + .fqs = rcu_sched_force_quiescent_state, .stats = NULL, .irq_capable = 1, .name = "sched" @@ -636,6 +653,7 @@ static struct rcu_torture_ops sched_sync_ops = { .deferred_free = rcu_sync_torture_deferred_free, .sync = sched_torture_synchronize, .cb_barrier = NULL, + .fqs = rcu_sched_force_quiescent_state, .stats = NULL, .name = "sched_sync" }; @@ -650,11 +668,44 @@ static struct rcu_torture_ops sched_expedited_ops = { .deferred_free = rcu_sync_torture_deferred_free, .sync = synchronize_sched_expedited, .cb_barrier = NULL, + .fqs = rcu_sched_force_quiescent_state, .stats = rcu_expedited_torture_stats, .irq_capable = 1, .name = "sched_expedited" }; +/* + * RCU torture force-quiescent-state kthread. Repeatedly induces + * bursts of calls to force_quiescent_state(), increasing the probability + * of occurrence of some important types of race conditions. + */ +static int +rcu_torture_fqs(void *arg) +{ + unsigned long fqs_resume_time; + int fqs_burst_remaining; + + VERBOSE_PRINTK_STRING("rcu_torture_fqs task started"); + do { + fqs_resume_time = jiffies + fqs_stutter * HZ; + while (jiffies - fqs_resume_time > LONG_MAX) { + schedule_timeout_interruptible(1); + } + fqs_burst_remaining = fqs_duration; + while (fqs_burst_remaining > 0) { + cur_ops->fqs(); + udelay(fqs_holdoff); + fqs_burst_remaining -= fqs_holdoff; + } + rcu_stutter_wait("rcu_torture_fqs"); + } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP); + VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping"); + rcutorture_shutdown_absorb("rcu_torture_fqs"); + while (!kthread_should_stop()) + schedule_timeout_uninterruptible(1); + return 0; +} + /* * RCU torture writer kthread. Repeatedly substitutes a new structure * for that pointed to by rcu_torture_current, freeing the old structure @@ -1030,10 +1081,11 @@ rcu_torture_print_module_parms(char *tag) printk(KERN_ALERT "%s" TORTURE_FLAG "--- %s: nreaders=%d nfakewriters=%d " "stat_interval=%d verbose=%d test_no_idle_hz=%d " - "shuffle_interval=%d stutter=%d irqreader=%d\n", + "shuffle_interval=%d stutter=%d irqreader=%d " + "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d\n", torture_type, tag, nrealreaders, nfakewriters, stat_interval, verbose, test_no_idle_hz, shuffle_interval, - stutter, irqreader); + stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter); } static struct notifier_block rcutorture_nb = { @@ -1109,6 +1161,12 @@ rcu_torture_cleanup(void) } stats_task = NULL; + if (fqs_task) { + VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task"); + kthread_stop(fqs_task); + } + fqs_task = NULL; + /* Wait for all RCU callbacks to fire. */ if (cur_ops->cb_barrier != NULL) @@ -1154,6 +1212,11 @@ rcu_torture_init(void) mutex_unlock(&fullstop_mutex); return -EINVAL; } + if (cur_ops->fqs == NULL && fqs_duration != 0) { + printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero " + "fqs_duration, fqs disabled.\n"); + fqs_duration = 0; + } if (cur_ops->init) cur_ops->init(); /* no "goto unwind" prior to this point!!! */ @@ -1282,6 +1345,19 @@ rcu_torture_init(void) goto unwind; } } + if (fqs_duration < 0) + fqs_duration = 0; + if (fqs_duration) { + /* Create the stutter thread */ + fqs_task = kthread_run(rcu_torture_fqs, NULL, + "rcu_torture_fqs"); + if (IS_ERR(fqs_task)) { + firsterr = PTR_ERR(fqs_task); + VERBOSE_PRINTK_ERRSTRING("Failed to create fqs"); + fqs_task = NULL; + goto unwind; + } + } register_reboot_notifier(&rcutorture_nb); mutex_unlock(&fullstop_mutex); return 0; diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 55e8f6ef8195..0a4c32879398 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -156,6 +156,24 @@ long rcu_batches_completed_bh(void) } EXPORT_SYMBOL_GPL(rcu_batches_completed_bh); +/* + * Force a quiescent state for RCU BH. + */ +void rcu_bh_force_quiescent_state(void) +{ + force_quiescent_state(&rcu_bh_state, 0); +} +EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state); + +/* + * Force a quiescent state for RCU-sched. + */ +void rcu_sched_force_quiescent_state(void) +{ + force_quiescent_state(&rcu_sched_state, 0); +} +EXPORT_SYMBOL_GPL(rcu_sched_force_quiescent_state); + /* * Does the CPU have callbacks ready to be invoked? */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 37fbccdf41d5..f11ebd44b454 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -61,6 +61,15 @@ long rcu_batches_completed(void) } EXPORT_SYMBOL_GPL(rcu_batches_completed); +/* + * Force a quiescent state for preemptible RCU. + */ +void rcu_force_quiescent_state(void) +{ + force_quiescent_state(&rcu_preempt_state, 0); +} +EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); + /* * Record a preemptable-RCU quiescent state for the specified CPU. Note * that this just means that the task currently running on the CPU is @@ -712,6 +721,16 @@ long rcu_batches_completed(void) } EXPORT_SYMBOL_GPL(rcu_batches_completed); +/* + * Force a quiescent state for RCU, which, because there is no preemptible + * RCU, becomes the same as rcu-sched. + */ +void rcu_force_quiescent_state(void) +{ + rcu_sched_force_quiescent_state(); +} +EXPORT_SYMBOL_GPL(rcu_force_quiescent_state); + /* * Because preemptable RCU does not exist, we never have to check for * CPUs being in quiescent states. -- cgit v1.2.3 From cba8244a0f1c277b6b1e48ed6504fa434119e24d Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 16:04:01 -0800 Subject: rcu: Add debug check for too many rcu_read_unlock() TREE_PREEMPT_RCU maintains an rcu_read_lock_nesting counter in the task structure, which happens to be a signed int. So this patch adds a check for this counter being negative at the end of __rcu_read_unlock(). This check is under CONFIG_PROVE_LOCKING, so can be thought of as being part of lockdep. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626498423064-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree_plugin.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index f11ebd44b454..e77cdf321e13 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -304,6 +304,9 @@ void __rcu_read_unlock(void) if (--ACCESS_ONCE(t->rcu_read_lock_nesting) == 0 && unlikely(ACCESS_ONCE(t->rcu_read_unlock_special))) rcu_read_unlock_special(t); +#ifdef CONFIG_PROVE_LOCKING + WARN_ON_ONCE(ACCESS_ONCE(t->rcu_read_lock_nesting) < 0); +#endif /* #ifdef CONFIG_PROVE_LOCKING */ } EXPORT_SYMBOL_GPL(__rcu_read_unlock); -- cgit v1.2.3 From b6407e863934965cdc66cbc244d811ceeb6f4d77 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 4 Jan 2010 16:04:02 -0800 Subject: rcu: Give different levels of the rcu_node hierarchy distinct lockdep names Previously, each level of the rcu_node hierarchy had the same rather unimaginative name: "&rcu_node_class[i]". This makes lockdep diagnostics involving these lockdep classes less helpful than would be nice. This patch fixes this by giving each level of the rcu_node hierarchy a distinct name: "rcu_node_level_0", "rcu_node_level_1", and so on. This version of the patch includes improved diagnostics suggested by Josh Triplett and Peter Zijlstra. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12626498421830-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 0a4c32879398..3b13d64b010b 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1811,11 +1811,17 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp) */ static void __init rcu_init_one(struct rcu_state *rsp) { + static char *buf[] = { "rcu_node_level_0", + "rcu_node_level_1", + "rcu_node_level_2", + "rcu_node_level_3" }; /* Match MAX_RCU_LVLS */ int cpustride = 1; int i; int j; struct rcu_node *rnp; + BUILD_BUG_ON(MAX_RCU_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */ + /* Initialize the level-tracking arrays. */ for (i = 1; i < NUM_RCU_LVLS; i++) @@ -1829,7 +1835,8 @@ static void __init rcu_init_one(struct rcu_state *rsp) rnp = rsp->level[i]; for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) { spin_lock_init(&rnp->lock); - lockdep_set_class(&rnp->lock, &rcu_node_class[i]); + lockdep_set_class_and_name(&rnp->lock, + &rcu_node_class[i], buf[i]); rnp->gpnum = 0; rnp->qsmask = 0; rnp->qsmaskinit = 0; -- cgit v1.2.3 From 14640106f243a3b29944d7198569090fa6546f2d Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 5 Jan 2010 17:46:48 -0500 Subject: tracing/kprobe: Drop function argument access syntax Drop function argument access syntax, because the function arguments depend on not only architecture but also compile-options and function API. And now, we have perf-probe for finding register/memory assigned to each argument. Signed-off-by: Masami Hiramatsu Cc: Frederic Weisbecker Cc: Arnaldo Carvalho de Melo Cc: systemtap Cc: DLE Cc: Frederic Weisbecker Cc: Steven Rostedt Cc: Roland McGrath Cc: Oleg Nesterov Cc: Mahesh Salgaonkar Cc: Benjamin Herrenschmidt Cc: Michael Neuling Cc: linuxppc-dev@ozlabs.org LKML-Reference: <20100105224648.19431.52309.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- Documentation/trace/kprobetrace.txt | 21 ++++++++++----------- kernel/trace/trace_kprobe.c | 18 +----------------- 2 files changed, 11 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index c3eff6ff945f..f30978e001f8 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -37,15 +37,12 @@ Synopsis of kprobe_events @SYM[+|-offs] : Fetch memory at SYM +|- offs (SYM should be a data symbol) $stackN : Fetch Nth entry of stack (N >= 0) $stack : Fetch stack address. - $argN : Fetch function argument. (N >= 0)(*) - $retval : Fetch return value.(**) - +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***) + $retval : Fetch return value.(*) + +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**) NAME=FETCHARG: Set NAME as the argument name of FETCHARG. - (*) aN may not correct on asmlinkaged functions and at the middle of - function body. - (**) only for return probe. - (***) this is useful for fetching a field of data structures. + (*) only for return probe. + (**) this is useful for fetching a field of data structures. Per-Probe Event Filtering @@ -82,11 +79,14 @@ Usage examples To add a probe as a new event, write a new definition to kprobe_events as below. - echo p:myprobe do_sys_open dfd=$arg0 filename=$arg1 flags=$arg2 mode=$arg3 > /sys/kernel/debug/tracing/kprobe_events + echo p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack) > /sys/kernel/debug/tracing/kprobe_events This sets a kprobe on the top of do_sys_open() function with recording -1st to 4th arguments as "myprobe" event. As this example shows, users can -choose more familiar names for each arguments. +1st to 4th arguments as "myprobe" event. Note, which register/stack entry is +assigned to each function argument depends on arch-specific ABI. If you unsure +the ABI, please try to use probe subcommand of perf-tools (you can find it +under tools/perf/). +As this example shows, users can choose more familiar names for each arguments. echo r:myretprobe do_sys_open $retval >> /sys/kernel/debug/tracing/kprobe_events @@ -147,4 +147,3 @@ events, you need to enable it. returns from SYMBOL(e.g. "sys_open+0x1b/0x1d <- do_sys_open" means kernel returns from do_sys_open to sys_open+0x1b). - diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 47f54ab57b68..7ac728ded964 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -91,11 +91,6 @@ static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr) return retval; } -static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num) -{ - return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num)); -} - static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs, void *dummy) { @@ -231,9 +226,7 @@ static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff) { int ret = -EINVAL; - if (ff->func == fetch_argument) - ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data); - else if (ff->func == fetch_register) { + if (ff->func == fetch_register) { const char *name; name = regs_query_register_name((unsigned int)((long)ff->data)); ret = snprintf(buf, n, "%%%s", name); @@ -489,14 +482,6 @@ static int parse_probe_vars(char *arg, struct fetch_func *ff, int is_return) } } else ret = -EINVAL; - } else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) { - ret = strict_strtoul(arg + 3, 10, ¶m); - if (ret || param > PARAM_MAX_ARGS) - ret = -EINVAL; - else { - ff->func = fetch_argument; - ff->data = (void *)param; - } } else ret = -EINVAL; return ret; @@ -611,7 +596,6 @@ static int create_trace_probe(int argc, char **argv) * - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS] * - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS] * Fetch args: - * $argN : fetch Nth of function argument. (N:0-) * $retval : fetch return value * $stack : fetch stack address * $stackN : fetch Nth of stack (N:0-) -- cgit v1.2.3 From 8381f65d097dad90416808314737dd7d3ae38ea9 Mon Sep 17 00:00:00 2001 From: Jamie Iles Date: Fri, 8 Jan 2010 15:27:33 +0000 Subject: sched/perf: Make sure irqs are disabled for perf_event_task_sched_in() perf_event_task_sched_in() expects interrupts to be disabled, but on architectures with __ARCH_WANT_INTERRUPTS_ON_CTXSW defined, this isn't true. If this is defined, disable irqs around the call in finish_task_switch(). Signed-off-by: Jamie Iles Acked-by: Peter Zijlstra Cc: Russell King - ARM Linux LKML-Reference: <1262964453-27370-1-git-send-email-jamie.iles@picochip.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index e507af086b42..c3ad3427a2a5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2783,7 +2783,13 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev) */ prev_state = prev->state; finish_arch_switch(prev); +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW + local_irq_disable(); +#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ perf_event_task_sched_in(current); +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW + local_irq_enable(); +#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */ finish_lock_switch(rq, prev); fire_sched_in_preempt_notifiers(current); -- cgit v1.2.3 From 017c426138122c8e9b9f5057fbd0567c37b35247 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Thu, 14 Jan 2010 16:10:58 -0800 Subject: rcu: Fix sparse warnings Rename local variable "i" in rcu_init() to avoid conflict with RCU_INIT_FLAVOR(), restrict the scope of RCU_TREE_NONCORE, and make __synchronize_srcu() static. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12635142581560-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 6 +++--- kernel/rcutree.h | 6 ++---- kernel/srcu.c | 2 +- 3 files changed, 6 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 3b13d64b010b..099a255ede4c 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1888,7 +1888,7 @@ do { \ void __init rcu_init(void) { - int i; + int cpu; rcu_bootup_announce(); #ifdef CONFIG_RCU_CPU_STALL_DETECTOR @@ -1908,8 +1908,8 @@ void __init rcu_init(void) * or the scheduler are operational. */ cpu_notifier(rcu_cpu_notify, 0); - for_each_online_cpu(i) - rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)i); + for_each_online_cpu(cpu) + rcu_cpu_notify(NULL, CPU_UP_PREPARE, (void *)(long)cpu); } #include "rcutree_plugin.h" diff --git a/kernel/rcutree.h b/kernel/rcutree.h index bd5d78ad1c48..d9d032abd665 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -323,8 +323,6 @@ struct rcu_state { #define RCU_OFL_TASKS_EXP_GP 0x2 /* Tasks blocking expedited */ /* GP were moved to root. */ -#ifdef RCU_TREE_NONCORE - /* * RCU implementation internal declarations: */ @@ -339,7 +337,7 @@ extern struct rcu_state rcu_preempt_state; DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data); #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -#else /* #ifdef RCU_TREE_NONCORE */ +#ifndef RCU_TREE_NONCORE /* Forward declarations for rcutree_plugin.h */ static void rcu_bootup_announce(void); @@ -372,4 +370,4 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu); static void rcu_preempt_send_cbs_to_orphanage(void); static void __init __rcu_init_preempt(void); -#endif /* #else #ifdef RCU_TREE_NONCORE */ +#endif /* #ifndef RCU_TREE_NONCORE */ diff --git a/kernel/srcu.c b/kernel/srcu.c index 818d7d9aa03c..31b275b9c112 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -144,7 +144,7 @@ EXPORT_SYMBOL_GPL(srcu_read_unlock); /* * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). */ -void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void)) +static void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void)) { int idx; -- cgit v1.2.3 From 889ff0150661512d79484219612b7e2e024b6c07 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 9 Jan 2010 20:04:47 +0100 Subject: perf/core: Split context's event group list into pinned and non-pinned lists Split-up struct perf_event_context::group_list into pinned_groups and flexible_groups (non-pinned). This first appears to be useless as it duplicates various loops around the group list handlings. But it scales better in the fast-path in perf_sched_in(). We don't anymore iterate twice through the entire list to separate pinned and non-pinned scheduling. Instead we interate through two distinct lists. The another desired effect is that it makes easier to define distinct scheduling rules on both. Changes in v2: - Respectively rename pinned_grp_list and volatile_grp_list into pinned_groups and flexible_groups as per Ingo suggestion. - Various cleanups Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- include/linux/perf_event.h | 3 +- kernel/perf_event.c | 227 ++++++++++++++++++++++++++++++--------------- 2 files changed, 153 insertions(+), 77 deletions(-) (limited to 'kernel') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 9a1d276db754..cdbc2aa64a0b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -683,7 +683,8 @@ struct perf_event_context { */ struct mutex mutex; - struct list_head group_list; + struct list_head pinned_groups; + struct list_head flexible_groups; struct list_head event_list; int nr_events; int nr_active; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 27f69a04541d..c9f8a757649d 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -289,6 +289,15 @@ static void update_event_times(struct perf_event *event) event->total_time_running = run_end - event->tstamp_running; } +static struct list_head * +ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) +{ + if (event->attr.pinned) + return &ctx->pinned_groups; + else + return &ctx->flexible_groups; +} + /* * Add a event from the lists for its context. * Must be called with ctx->mutex and ctx->lock held. @@ -303,9 +312,12 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) * add it straight to the context's event list, or to the group * leader's sibling list: */ - if (group_leader == event) - list_add_tail(&event->group_entry, &ctx->group_list); - else { + if (group_leader == event) { + struct list_head *list; + + list = ctx_group_list(event, ctx); + list_add_tail(&event->group_entry, list); + } else { list_add_tail(&event->group_entry, &group_leader->sibling_list); group_leader->nr_siblings++; } @@ -355,8 +367,10 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) * to the context list directly: */ list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { + struct list_head *list; - list_move_tail(&sibling->group_entry, &ctx->group_list); + list = ctx_group_list(event, ctx); + list_move_tail(&sibling->group_entry, list); sibling->group_leader = sibling; } } @@ -1056,7 +1070,10 @@ void __perf_event_sched_out(struct perf_event_context *ctx, perf_disable(); if (ctx->nr_active) { - list_for_each_entry(event, &ctx->group_list, group_entry) + list_for_each_entry(event, &ctx->pinned_groups, group_entry) + group_sched_out(event, cpuctx, ctx); + + list_for_each_entry(event, &ctx->flexible_groups, group_entry) group_sched_out(event, cpuctx, ctx); } perf_enable(); @@ -1271,9 +1288,8 @@ __perf_event_sched_in(struct perf_event_context *ctx, * First go through the list and put on any pinned groups * in order to give them the best chance of going on. */ - list_for_each_entry(event, &ctx->group_list, group_entry) { - if (event->state <= PERF_EVENT_STATE_OFF || - !event->attr.pinned) + list_for_each_entry(event, &ctx->pinned_groups, group_entry) { + if (event->state <= PERF_EVENT_STATE_OFF) continue; if (event->cpu != -1 && event->cpu != cpu) continue; @@ -1291,15 +1307,10 @@ __perf_event_sched_in(struct perf_event_context *ctx, } } - list_for_each_entry(event, &ctx->group_list, group_entry) { - /* - * Ignore events in OFF or ERROR state, and - * ignore pinned events since we did them already. - */ - if (event->state <= PERF_EVENT_STATE_OFF || - event->attr.pinned) + list_for_each_entry(event, &ctx->flexible_groups, group_entry) { + /* Ignore events in OFF or ERROR state */ + if (event->state <= PERF_EVENT_STATE_OFF) continue; - /* * Listen to the 'cpu' scheduling filter constraint * of events: @@ -1453,8 +1464,13 @@ static void rotate_ctx(struct perf_event_context *ctx) * Rotate the first entry last (works just fine for group events too): */ perf_disable(); - list_for_each_entry(event, &ctx->group_list, group_entry) { - list_move_tail(&event->group_entry, &ctx->group_list); + list_for_each_entry(event, &ctx->pinned_groups, group_entry) { + list_move_tail(&event->group_entry, &ctx->pinned_groups); + break; + } + + list_for_each_entry(event, &ctx->flexible_groups, group_entry) { + list_move_tail(&event->group_entry, &ctx->flexible_groups); break; } perf_enable(); @@ -1490,6 +1506,21 @@ void perf_event_task_tick(struct task_struct *curr) perf_event_task_sched_in(curr); } +static int event_enable_on_exec(struct perf_event *event, + struct perf_event_context *ctx) +{ + if (!event->attr.enable_on_exec) + return 0; + + event->attr.enable_on_exec = 0; + if (event->state >= PERF_EVENT_STATE_INACTIVE) + return 0; + + __perf_event_mark_enabled(event, ctx); + + return 1; +} + /* * Enable all of a task's events that have been marked enable-on-exec. * This expects task == current. @@ -1500,6 +1531,7 @@ static void perf_event_enable_on_exec(struct task_struct *task) struct perf_event *event; unsigned long flags; int enabled = 0; + int ret; local_irq_save(flags); ctx = task->perf_event_ctxp; @@ -1510,14 +1542,16 @@ static void perf_event_enable_on_exec(struct task_struct *task) raw_spin_lock(&ctx->lock); - list_for_each_entry(event, &ctx->group_list, group_entry) { - if (!event->attr.enable_on_exec) - continue; - event->attr.enable_on_exec = 0; - if (event->state >= PERF_EVENT_STATE_INACTIVE) - continue; - __perf_event_mark_enabled(event, ctx); - enabled = 1; + list_for_each_entry(event, &ctx->pinned_groups, group_entry) { + ret = event_enable_on_exec(event, ctx); + if (ret) + enabled = 1; + } + + list_for_each_entry(event, &ctx->flexible_groups, group_entry) { + ret = event_enable_on_exec(event, ctx); + if (ret) + enabled = 1; } /* @@ -1591,7 +1625,8 @@ __perf_event_init_context(struct perf_event_context *ctx, { raw_spin_lock_init(&ctx->lock); mutex_init(&ctx->mutex); - INIT_LIST_HEAD(&ctx->group_list); + INIT_LIST_HEAD(&ctx->pinned_groups); + INIT_LIST_HEAD(&ctx->flexible_groups); INIT_LIST_HEAD(&ctx->event_list); atomic_set(&ctx->refcount, 1); ctx->task = task; @@ -5032,7 +5067,11 @@ void perf_event_exit_task(struct task_struct *child) mutex_lock_nested(&child_ctx->mutex, SINGLE_DEPTH_NESTING); again: - list_for_each_entry_safe(child_event, tmp, &child_ctx->group_list, + list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups, + group_entry) + __perf_event_exit_task(child_event, child_ctx, child); + + list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups, group_entry) __perf_event_exit_task(child_event, child_ctx, child); @@ -5041,7 +5080,8 @@ again: * its siblings to the list, but we obtained 'tmp' before that which * will still point to the list head terminating the iteration. */ - if (!list_empty(&child_ctx->group_list)) + if (!list_empty(&child_ctx->pinned_groups) || + !list_empty(&child_ctx->flexible_groups)) goto again; mutex_unlock(&child_ctx->mutex); @@ -5049,6 +5089,24 @@ again: put_ctx(child_ctx); } +static void perf_free_event(struct perf_event *event, + struct perf_event_context *ctx) +{ + struct perf_event *parent = event->parent; + + if (WARN_ON_ONCE(!parent)) + return; + + mutex_lock(&parent->child_mutex); + list_del_init(&event->child_list); + mutex_unlock(&parent->child_mutex); + + fput(parent->filp); + + list_del_event(event, ctx); + free_event(event); +} + /* * free an unexposed, unused context as created by inheritance by * init_task below, used by fork() in case of fail. @@ -5063,36 +5121,70 @@ void perf_event_free_task(struct task_struct *task) mutex_lock(&ctx->mutex); again: - list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry) { - struct perf_event *parent = event->parent; + list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) + perf_free_event(event, ctx); - if (WARN_ON_ONCE(!parent)) - continue; + list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, + group_entry) + perf_free_event(event, ctx); - mutex_lock(&parent->child_mutex); - list_del_init(&event->child_list); - mutex_unlock(&parent->child_mutex); + if (!list_empty(&ctx->pinned_groups) || + !list_empty(&ctx->flexible_groups)) + goto again; - fput(parent->filp); + mutex_unlock(&ctx->mutex); - list_del_event(event, ctx); - free_event(event); + put_ctx(ctx); +} + +static int +inherit_task_group(struct perf_event *event, struct task_struct *parent, + struct perf_event_context *parent_ctx, + struct task_struct *child, + int *inherited_all) +{ + int ret; + struct perf_event_context *child_ctx = child->perf_event_ctxp; + + if (!event->attr.inherit) { + *inherited_all = 0; + return 0; } - if (!list_empty(&ctx->group_list)) - goto again; + if (!child_ctx) { + /* + * This is executed from the parent task context, so + * inherit events that have been marked for cloning. + * First allocate and initialize a context for the + * child. + */ - mutex_unlock(&ctx->mutex); + child_ctx = kzalloc(sizeof(struct perf_event_context), + GFP_KERNEL); + if (!child_ctx) + return -ENOMEM; - put_ctx(ctx); + __perf_event_init_context(child_ctx, child); + child->perf_event_ctxp = child_ctx; + get_task_struct(child); + } + + ret = inherit_group(event, parent, parent_ctx, + child, child_ctx); + + if (ret) + *inherited_all = 0; + + return ret; } + /* * Initialize the perf_event context in task_struct */ int perf_event_init_task(struct task_struct *child) { - struct perf_event_context *child_ctx = NULL, *parent_ctx; + struct perf_event_context *child_ctx, *parent_ctx; struct perf_event_context *cloned_ctx; struct perf_event *event; struct task_struct *parent = current; @@ -5130,41 +5222,22 @@ int perf_event_init_task(struct task_struct *child) * We dont have to disable NMIs - we are only looking at * the list, not manipulating it: */ - list_for_each_entry(event, &parent_ctx->group_list, group_entry) { - - if (!event->attr.inherit) { - inherited_all = 0; - continue; - } - - if (!child->perf_event_ctxp) { - /* - * This is executed from the parent task context, so - * inherit events that have been marked for cloning. - * First allocate and initialize a context for the - * child. - */ - - child_ctx = kzalloc(sizeof(struct perf_event_context), - GFP_KERNEL); - if (!child_ctx) { - ret = -ENOMEM; - break; - } - - __perf_event_init_context(child_ctx, child); - child->perf_event_ctxp = child_ctx; - get_task_struct(child); - } + list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { + ret = inherit_task_group(event, parent, parent_ctx, child, + &inherited_all); + if (ret) + break; + } - ret = inherit_group(event, parent, parent_ctx, - child, child_ctx); - if (ret) { - inherited_all = 0; + list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { + ret = inherit_task_group(event, parent, parent_ctx, child, + &inherited_all); + if (ret) break; - } } + child_ctx = child->perf_event_ctxp; + if (child_ctx && inherited_all) { /* * Mark the child context as a clone of the parent @@ -5213,7 +5286,9 @@ static void __perf_event_exit_cpu(void *info) struct perf_event_context *ctx = &cpuctx->ctx; struct perf_event *event, *tmp; - list_for_each_entry_safe(event, tmp, &ctx->group_list, group_entry) + list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry) + __perf_event_remove_from_context(event); + list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry) __perf_event_remove_from_context(event); } static void perf_event_exit_cpu(int cpu) -- cgit v1.2.3 From e286417378b4f9ce6e473b556193465ab22e12ab Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 9 Jan 2010 21:05:28 +0100 Subject: perf: Round robin flexible groups of events using list_rotate_left() This is more proper that doing it through a list_for_each_entry() that breaks after the first entry. v2: Don't rotate pinned groups as its not needed to time share them. Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- kernel/perf_event.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index c9f8a757649d..bbebe2832639 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1454,25 +1454,16 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx) */ static void rotate_ctx(struct perf_event_context *ctx) { - struct perf_event *event; - if (!ctx->nr_events) return; raw_spin_lock(&ctx->lock); - /* - * Rotate the first entry last (works just fine for group events too): - */ + + /* Rotate the first entry last of non-pinned groups */ perf_disable(); - list_for_each_entry(event, &ctx->pinned_groups, group_entry) { - list_move_tail(&event->group_entry, &ctx->pinned_groups); - break; - } - list_for_each_entry(event, &ctx->flexible_groups, group_entry) { - list_move_tail(&event->group_entry, &ctx->flexible_groups); - break; - } + list_rotate_left(&ctx->flexible_groups); + perf_enable(); raw_spin_unlock(&ctx->lock); -- cgit v1.2.3 From d6f962b57bfaab62891c7abbf1469212a56d6103 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 10 Jan 2010 01:25:51 +0100 Subject: perf: Export software-only event group characteristic as a flag Before scheduling an event group, we first check if a group can go on. We first check if the group is made of software only events first, in which case it is enough to know if the group can be scheduled in. For that purpose, we iterate through the whole group, which is wasteful as we could do this check when we add/delete an event to a group. So we create a group_flags field in perf event that can host characteristics from a group of events, starting with a first PERF_GROUP_SOFTWARE flag that reduces the check on the fast path. Signed-off-by: Frederic Weisbecker Acked-by: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- include/linux/perf_event.h | 5 +++++ kernel/perf_event.c | 30 +++++++++++------------------- 2 files changed, 16 insertions(+), 19 deletions(-) (limited to 'kernel') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index cdbc2aa64a0b..c6f812e4d058 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -565,6 +565,10 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, int, struct perf_sample_data *, struct pt_regs *regs); +enum perf_group_flag { + PERF_GROUP_SOFTWARE = 0x1, +}; + /** * struct perf_event - performance event kernel representation: */ @@ -574,6 +578,7 @@ struct perf_event { struct list_head event_entry; struct list_head sibling_list; int nr_siblings; + int group_flags; struct perf_event *group_leader; struct perf_event *output; const struct pmu *pmu; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index bbebe2832639..eae6ff693604 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -315,9 +315,16 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx) if (group_leader == event) { struct list_head *list; + if (is_software_event(event)) + event->group_flags |= PERF_GROUP_SOFTWARE; + list = ctx_group_list(event, ctx); list_add_tail(&event->group_entry, list); } else { + if (group_leader->group_flags & PERF_GROUP_SOFTWARE && + !is_software_event(event)) + group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; + list_add_tail(&event->group_entry, &group_leader->sibling_list); group_leader->nr_siblings++; } @@ -372,6 +379,9 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx) list = ctx_group_list(event, ctx); list_move_tail(&sibling->group_entry, list); sibling->group_leader = sibling; + + /* Inherit group flags from the previous leader */ + sibling->group_flags = event->group_flags; } } @@ -699,24 +709,6 @@ group_error: return -EAGAIN; } -/* - * Return 1 for a group consisting entirely of software events, - * 0 if the group contains any hardware events. - */ -static int is_software_only_group(struct perf_event *leader) -{ - struct perf_event *event; - - if (!is_software_event(leader)) - return 0; - - list_for_each_entry(event, &leader->sibling_list, group_entry) - if (!is_software_event(event)) - return 0; - - return 1; -} - /* * Work out whether we can put this event group on the CPU now. */ @@ -727,7 +719,7 @@ static int group_can_go_on(struct perf_event *event, /* * Groups consisting entirely of software events can always go on. */ - if (is_software_only_group(event)) + if (event->group_flags & PERF_GROUP_SOFTWARE) return 1; /* * If an exclusive group is already on, no other hardware -- cgit v1.2.3 From 24a53652e361321b09df5040711e69387344ce09 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 14 Jan 2010 08:23:15 +0100 Subject: tracing: Drop the tr check from the graph tracing path Each time we save a function entry from the function graph tracer, we check if the trace array is set, which is wasteful because it is set anyway before we start the tracer. All we need is to ensure we have good read and write orderings. When we set the trace array, we just need to guarantee it to be visible before starting tracing. Signed-off-by: Frederic Weisbecker Acked-by: Steven Rostedt Cc: Lai Jiangshan Cc: Paul E. McKenney LKML-Reference: <1263453795-7496-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace_functions_graph.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index b1342c5d37cf..f2252296607c 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -212,9 +212,6 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) int cpu; int pc; - if (unlikely(!tr)) - return 0; - if (!ftrace_trace_task(current)) return 0; @@ -287,11 +284,20 @@ void trace_graph_return(struct ftrace_graph_ret *trace) local_irq_restore(flags); } +void set_graph_array(struct trace_array *tr) +{ + graph_array = tr; + + /* Make graph_array visible before we start tracing */ + + smp_mb(); +} + static int graph_trace_init(struct trace_array *tr) { int ret; - graph_array = tr; + set_graph_array(tr); ret = register_ftrace_graph(&trace_graph_return, &trace_graph_entry); if (ret) @@ -301,11 +307,6 @@ static int graph_trace_init(struct trace_array *tr) return 0; } -void set_graph_array(struct trace_array *tr) -{ - graph_array = tr; -} - static void graph_trace_reset(struct trace_array *tr) { tracing_stop_cmdline_record(); -- cgit v1.2.3 From 6d686f4564f3fc7c6e678852919e48ad331d276b Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Wed, 13 Jan 2010 20:21:52 -0700 Subject: sched: Don't expose local functions kernel/sched: don't expose local functions The get_rr_interval_* functions are all class methods of struct sched_class. They are not exported so make them static. Signed-off-by: H Hartley Sweeten Cc: Peter Zijlstra LKML-Reference: <201001132021.53253.hartleys@visionengravers.com> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 2 +- kernel/sched_idletask.c | 2 +- kernel/sched_rt.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 42ac3c9f66f6..71778601c103 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2076,7 +2076,7 @@ static void moved_group_fair(struct task_struct *p, int on_rq) } #endif -unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) +static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) { struct sched_entity *se = &task->se; unsigned int rr_interval = 0; diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c index 5f93b570d383..01332bfc61a7 100644 --- a/kernel/sched_idletask.c +++ b/kernel/sched_idletask.c @@ -97,7 +97,7 @@ static void prio_changed_idle(struct rq *rq, struct task_struct *p, check_preempt_curr(rq, p, 0); } -unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task) +static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task) { return 0; } diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index f48328ac216f..072b3fcee8d8 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1721,7 +1721,7 @@ static void set_curr_task_rt(struct rq *rq) dequeue_pushable_task(rq, p); } -unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) +static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) { /* * Time slice is 0 for SCHED_FIFO tasks -- cgit v1.2.3 From 231e36f4d2e63dd770db80b9f5113310c2bcfcfd Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 14 Jan 2010 00:12:12 -0500 Subject: tracing/kprobe: Update kprobe tracing self test for new syntax Update kprobe tracing self test for new syntax (it supports deleting individual probes, and drops $argN support) and behavior change (new probes are disabled in default). This selftest includes the following checks: - Adding function-entry probe and return probe with arguments. - Enabling these probes. - Deleting it individually. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <20100114051211.7814.29436.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar --- kernel/trace/trace_kprobe.c | 55 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 47 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 7ac728ded964..d6266cad6953 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1507,28 +1507,67 @@ static int kprobe_trace_selftest_target(int a1, int a2, int a3, static __init int kprobe_trace_self_tests_init(void) { - int ret; + int ret, warn = 0; int (*target)(int, int, int, int, int, int); + struct trace_probe *tp; target = kprobe_trace_selftest_target; pr_info("Testing kprobe tracing: "); ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target " - "$arg1 $arg2 $arg3 $arg4 $stack $stack0"); - if (WARN_ON_ONCE(ret)) - pr_warning("error enabling function entry\n"); + "$stack $stack0 +0($stack)"); + if (WARN_ON_ONCE(ret)) { + pr_warning("error on probing function entry.\n"); + warn++; + } else { + /* Enable trace point */ + tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM); + if (WARN_ON_ONCE(tp == NULL)) { + pr_warning("error on getting new probe.\n"); + warn++; + } else + probe_event_enable(&tp->call); + } ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target " "$retval"); - if (WARN_ON_ONCE(ret)) - pr_warning("error enabling function return\n"); + if (WARN_ON_ONCE(ret)) { + pr_warning("error on probing function return.\n"); + warn++; + } else { + /* Enable trace point */ + tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM); + if (WARN_ON_ONCE(tp == NULL)) { + pr_warning("error on getting new probe.\n"); + warn++; + } else + probe_event_enable(&tp->call); + } + + if (warn) + goto end; ret = target(1, 2, 3, 4, 5, 6); - cleanup_all_probes(); + ret = command_trace_probe("-:testprobe"); + if (WARN_ON_ONCE(ret)) { + pr_warning("error on deleting a probe.\n"); + warn++; + } + + ret = command_trace_probe("-:testprobe2"); + if (WARN_ON_ONCE(ret)) { + pr_warning("error on deleting a probe.\n"); + warn++; + } - pr_cont("OK\n"); +end: + cleanup_all_probes(); + if (warn) + pr_cont("NG: Some tests are failed. Please check them.\n"); + else + pr_cont("OK\n"); return 0; } -- cgit v1.2.3 From 42cce92f4ddfa41e2dfe26fdcad4887943c032f2 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 17 Jan 2010 10:36:08 +0100 Subject: perf: Make __perf_event_sched_out static __perf_event_sched_out doesn't need to be globally available, make it static. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- kernel/perf_event.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index eae6ff693604..c4e90b8cd60d 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1049,8 +1049,8 @@ static int perf_event_refresh(struct perf_event *event, int refresh) return 0; } -void __perf_event_sched_out(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx) +static void __perf_event_sched_out(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx) { struct perf_event *event; -- cgit v1.2.3 From 5b0311e1f2464547fc6f17a82d7ea2538c8c7a70 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 17 Jan 2010 11:59:13 +0100 Subject: perf: Allow pinned and flexible groups to be scheduled separately Tune the scheduling helpers so that we can choose to schedule either pinned and/or flexible groups from a context. And while at it, refactor a bit the naming of these helpers to make these more consistent and flexible. There is no (intended) change in scheduling behaviour in this patch. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- kernel/perf_event.c | 137 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 93 insertions(+), 44 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index c4e90b8cd60d..bfc4ee015c87 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1049,8 +1049,15 @@ static int perf_event_refresh(struct perf_event *event, int refresh) return 0; } -static void __perf_event_sched_out(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx) +enum event_type_t { + EVENT_FLEXIBLE = 0x1, + EVENT_PINNED = 0x2, + EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, +}; + +static void ctx_sched_out(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type) { struct perf_event *event; @@ -1061,13 +1068,18 @@ static void __perf_event_sched_out(struct perf_event_context *ctx, update_context_time(ctx); perf_disable(); - if (ctx->nr_active) { + if (!ctx->nr_active) + goto out_enable; + + if (event_type & EVENT_PINNED) list_for_each_entry(event, &ctx->pinned_groups, group_entry) group_sched_out(event, cpuctx, ctx); + if (event_type & EVENT_FLEXIBLE) list_for_each_entry(event, &ctx->flexible_groups, group_entry) group_sched_out(event, cpuctx, ctx); - } + + out_enable: perf_enable(); out: raw_spin_unlock(&ctx->lock); @@ -1229,15 +1241,13 @@ void perf_event_task_sched_out(struct task_struct *task, rcu_read_unlock(); if (do_switch) { - __perf_event_sched_out(ctx, cpuctx); + ctx_sched_out(ctx, cpuctx, EVENT_ALL); cpuctx->task_ctx = NULL; } } -/* - * Called with IRQs disabled - */ -static void __perf_event_task_sched_out(struct perf_event_context *ctx) +static void task_ctx_sched_out(struct perf_event_context *ctx, + enum event_type_t event_type) { struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); @@ -1247,39 +1257,34 @@ static void __perf_event_task_sched_out(struct perf_event_context *ctx) if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) return; - __perf_event_sched_out(ctx, cpuctx); + ctx_sched_out(ctx, cpuctx, event_type); cpuctx->task_ctx = NULL; } /* * Called with IRQs disabled */ -static void perf_event_cpu_sched_out(struct perf_cpu_context *cpuctx) +static void __perf_event_task_sched_out(struct perf_event_context *ctx) { - __perf_event_sched_out(&cpuctx->ctx, cpuctx); + task_ctx_sched_out(ctx, EVENT_ALL); +} + +/* + * Called with IRQs disabled + */ +static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); } static void -__perf_event_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx) +ctx_pinned_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + int cpu) { - int cpu = smp_processor_id(); struct perf_event *event; - int can_add_hw = 1; - - raw_spin_lock(&ctx->lock); - ctx->is_active = 1; - if (likely(!ctx->nr_events)) - goto out; - - ctx->timestamp = perf_clock(); - - perf_disable(); - /* - * First go through the list and put on any pinned groups - * in order to give them the best chance of going on. - */ list_for_each_entry(event, &ctx->pinned_groups, group_entry) { if (event->state <= PERF_EVENT_STATE_OFF) continue; @@ -1298,6 +1303,15 @@ __perf_event_sched_in(struct perf_event_context *ctx, event->state = PERF_EVENT_STATE_ERROR; } } +} + +static void +ctx_flexible_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + int cpu) +{ + struct perf_event *event; + int can_add_hw = 1; list_for_each_entry(event, &ctx->flexible_groups, group_entry) { /* Ignore events in OFF or ERROR state */ @@ -1314,11 +1328,53 @@ __perf_event_sched_in(struct perf_event_context *ctx, if (group_sched_in(event, cpuctx, ctx, cpu)) can_add_hw = 0; } +} + +static void +ctx_sched_in(struct perf_event_context *ctx, + struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + int cpu = smp_processor_id(); + + raw_spin_lock(&ctx->lock); + ctx->is_active = 1; + if (likely(!ctx->nr_events)) + goto out; + + ctx->timestamp = perf_clock(); + + perf_disable(); + + /* + * First go through the list and put on any pinned groups + * in order to give them the best chance of going on. + */ + if (event_type & EVENT_PINNED) + ctx_pinned_sched_in(ctx, cpuctx, cpu); + + /* Then walk through the lower prio flexible groups */ + if (event_type & EVENT_FLEXIBLE) + ctx_flexible_sched_in(ctx, cpuctx, cpu); + perf_enable(); out: raw_spin_unlock(&ctx->lock); } +static void task_ctx_sched_in(struct task_struct *task, + enum event_type_t event_type) +{ + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); + struct perf_event_context *ctx = task->perf_event_ctxp; + + if (likely(!ctx)) + return; + if (cpuctx->task_ctx == ctx) + return; + ctx_sched_in(ctx, cpuctx, event_type); + cpuctx->task_ctx = ctx; +} /* * Called from scheduler to add the events of the current task * with interrupts disabled. @@ -1332,22 +1388,15 @@ __perf_event_sched_in(struct perf_event_context *ctx, */ void perf_event_task_sched_in(struct task_struct *task) { - struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); - struct perf_event_context *ctx = task->perf_event_ctxp; - - if (likely(!ctx)) - return; - if (cpuctx->task_ctx == ctx) - return; - __perf_event_sched_in(ctx, cpuctx); - cpuctx->task_ctx = ctx; + task_ctx_sched_in(task, EVENT_ALL); } -static void perf_event_cpu_sched_in(struct perf_cpu_context *cpuctx) +static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, + enum event_type_t event_type) { struct perf_event_context *ctx = &cpuctx->ctx; - __perf_event_sched_in(ctx, cpuctx); + ctx_sched_in(ctx, cpuctx, event_type); } #define MAX_INTERRUPTS (~0ULL) @@ -1476,17 +1525,17 @@ void perf_event_task_tick(struct task_struct *curr) if (ctx) perf_ctx_adjust_freq(ctx); - perf_event_cpu_sched_out(cpuctx); + cpu_ctx_sched_out(cpuctx, EVENT_ALL); if (ctx) - __perf_event_task_sched_out(ctx); + task_ctx_sched_out(ctx, EVENT_ALL); rotate_ctx(&cpuctx->ctx); if (ctx) rotate_ctx(ctx); - perf_event_cpu_sched_in(cpuctx); + cpu_ctx_sched_in(cpuctx, EVENT_ALL); if (ctx) - perf_event_task_sched_in(curr); + task_ctx_sched_in(curr, EVENT_ALL); } static int event_enable_on_exec(struct perf_event *event, -- cgit v1.2.3 From 7defb0f879bbcfe29e3c6f29d685d4f29b7a0700 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 17 Jan 2010 12:15:31 +0100 Subject: perf: Don't schedule out/in pinned events on task tick We don't need to schedule in/out pinned events on task tick, now that pinned and flexible groups can be scheduled separately. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- kernel/perf_event.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index bfc4ee015c87..a90ae694cbc1 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1525,17 +1525,17 @@ void perf_event_task_tick(struct task_struct *curr) if (ctx) perf_ctx_adjust_freq(ctx); - cpu_ctx_sched_out(cpuctx, EVENT_ALL); + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); if (ctx) - task_ctx_sched_out(ctx, EVENT_ALL); + task_ctx_sched_out(ctx, EVENT_FLEXIBLE); rotate_ctx(&cpuctx->ctx); if (ctx) rotate_ctx(ctx); - cpu_ctx_sched_in(cpuctx, EVENT_ALL); + cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); if (ctx) - task_ctx_sched_in(curr, EVENT_ALL); + task_ctx_sched_in(curr, EVENT_FLEXIBLE); } static int event_enable_on_exec(struct perf_event *event, -- cgit v1.2.3 From 329c0e012b99fa2325a0be205c052e4aba690f16 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 17 Jan 2010 12:56:05 +0100 Subject: perf: Better order flexible and pinned scheduling When a task gets scheduled in. We don't touch the cpu bound events so the priority order becomes: cpu pinned, cpu flexible, task pinned, task flexible. So schedule out cpu flexibles when a new task context gets in and correctly order the groups to schedule in: task pinned, cpu flexible, task flexible. Cpu pinned groups don't need to be touched at this time. Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- kernel/perf_event.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index a90ae694cbc1..edc46b92b508 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1362,6 +1362,14 @@ ctx_sched_in(struct perf_event_context *ctx, raw_spin_unlock(&ctx->lock); } +static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, + enum event_type_t event_type) +{ + struct perf_event_context *ctx = &cpuctx->ctx; + + ctx_sched_in(ctx, cpuctx, event_type); +} + static void task_ctx_sched_in(struct task_struct *task, enum event_type_t event_type) { @@ -1388,15 +1396,27 @@ static void task_ctx_sched_in(struct task_struct *task, */ void perf_event_task_sched_in(struct task_struct *task) { - task_ctx_sched_in(task, EVENT_ALL); -} + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); + struct perf_event_context *ctx = task->perf_event_ctxp; -static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, - enum event_type_t event_type) -{ - struct perf_event_context *ctx = &cpuctx->ctx; + if (likely(!ctx)) + return; - ctx_sched_in(ctx, cpuctx, event_type); + if (cpuctx->task_ctx == ctx) + return; + + /* + * We want to keep the following priority order: + * cpu pinned (that don't need to move), task pinned, + * cpu flexible, task flexible. + */ + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + + ctx_sched_in(ctx, cpuctx, EVENT_PINNED); + cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); + ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE); + + cpuctx->task_ctx = ctx; } #define MAX_INTERRUPTS (~0ULL) -- cgit v1.2.3 From e03bcb68629c7f0728c95f1afe06ce48565c7713 Mon Sep 17 00:00:00 2001 From: Milton Miller Date: Mon, 18 Jan 2010 13:00:51 +1100 Subject: generic-ipi: Optimize accesses by using DEFINE_PER_CPU_SHARED_ALIGNED for IPI data The smp ipi data is passed around and given write access by other cpus and should be separated from per-cpu data consumed by this cpu. Looking for hot lines, I saw call_function_data shared with tick_cpu_sched. Signed-off-by: Milton Miller Acked-by: Anton Blanchard Acked-by: Jens Axboe Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Cc: : Nick Piggin LKML-Reference: <20100118020051.GR12666@kryten> Signed-off-by: Ingo Molnar --- kernel/smp.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/smp.c b/kernel/smp.c index f10408422444..9867b6bfefce 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -12,8 +12,6 @@ #include #include -static DEFINE_PER_CPU(struct call_single_queue, call_single_queue); - static struct { struct list_head queue; raw_spinlock_t lock; @@ -33,12 +31,14 @@ struct call_function_data { cpumask_var_t cpumask; }; +static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data); + struct call_single_queue { struct list_head list; raw_spinlock_t lock; }; -static DEFINE_PER_CPU(struct call_function_data, cfd_data); +static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_queue, call_single_queue); static int hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu) @@ -256,7 +256,7 @@ void generic_smp_call_function_single_interrupt(void) } } -static DEFINE_PER_CPU(struct call_single_data, csd_data); +static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data); /* * smp_call_function_single - Run a function on a specific CPU -- cgit v1.2.3 From 1e3c88bdeb1260edc341e45c9fb8efd182a5c511 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 17:00:43 +0100 Subject: sched: Move load balance code into sched_fair.c Straight fwd code movement. Since non of the load-balance abstractions are used anymore, do away with them and simplify the code some. In preparation move the code around. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched.c | 1919 +++------------------------------------------------ kernel/sched_fair.c | 1765 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 1844 insertions(+), 1840 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 64298a52eaa6..13a2acf18b2d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1805,6 +1805,51 @@ static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest) raw_spin_unlock(&busiest->lock); lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_); } + +/* + * double_rq_lock - safely lock two runqueues + * + * Note this does not disable interrupts like task_rq_lock, + * you need to do so manually before calling. + */ +static void double_rq_lock(struct rq *rq1, struct rq *rq2) + __acquires(rq1->lock) + __acquires(rq2->lock) +{ + BUG_ON(!irqs_disabled()); + if (rq1 == rq2) { + raw_spin_lock(&rq1->lock); + __acquire(rq2->lock); /* Fake it out ;) */ + } else { + if (rq1 < rq2) { + raw_spin_lock(&rq1->lock); + raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING); + } else { + raw_spin_lock(&rq2->lock); + raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING); + } + } + update_rq_clock(rq1); + update_rq_clock(rq2); +} + +/* + * double_rq_unlock - safely unlock two runqueues + * + * Note this does not restore interrupts like task_rq_unlock, + * you need to do so manually after calling. + */ +static void double_rq_unlock(struct rq *rq1, struct rq *rq2) + __releases(rq1->lock) + __releases(rq2->lock) +{ + raw_spin_unlock(&rq1->lock); + if (rq1 != rq2) + raw_spin_unlock(&rq2->lock); + else + __release(rq2->lock); +} + #endif #ifdef CONFIG_FAIR_GROUP_SCHED @@ -1834,18 +1879,14 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) #endif } -#include "sched_stats.h" -#include "sched_idletask.c" -#include "sched_fair.c" -#include "sched_rt.c" -#ifdef CONFIG_SCHED_DEBUG -# include "sched_debug.c" -#endif +static const struct sched_class rt_sched_class; #define sched_class_highest (&rt_sched_class) #define for_each_class(class) \ for (class = sched_class_highest; class; class = class->next) +#include "sched_stats.h" + static void inc_nr_running(struct rq *rq) { rq->nr_running++; @@ -1911,6 +1952,37 @@ static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) p->se.on_rq = 0; } +/* + * activate_task - move a task to the runqueue. + */ +static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) +{ + if (task_contributes_to_load(p)) + rq->nr_uninterruptible--; + + enqueue_task(rq, p, wakeup); + inc_nr_running(rq); +} + +/* + * deactivate_task - remove a task from the runqueue. + */ +static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) +{ + if (task_contributes_to_load(p)) + rq->nr_uninterruptible++; + + dequeue_task(rq, p, sleep); + dec_nr_running(rq); +} + +#include "sched_idletask.c" +#include "sched_fair.c" +#include "sched_rt.c" +#ifdef CONFIG_SCHED_DEBUG +# include "sched_debug.c" +#endif + /* * __normal_prio - return the priority that is based on the static prio */ @@ -1957,30 +2029,6 @@ static int effective_prio(struct task_struct *p) return p->prio; } -/* - * activate_task - move a task to the runqueue. - */ -static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) -{ - if (task_contributes_to_load(p)) - rq->nr_uninterruptible--; - - enqueue_task(rq, p, wakeup); - inc_nr_running(rq); -} - -/* - * deactivate_task - remove a task from the runqueue. - */ -static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) -{ - if (task_contributes_to_load(p)) - rq->nr_uninterruptible++; - - dequeue_task(rq, p, sleep); - dec_nr_running(rq); -} - /** * task_curr - is this task currently executing on a CPU? * @p: the task in question. @@ -3087,50 +3135,6 @@ static void update_cpu_load(struct rq *this_rq) #ifdef CONFIG_SMP -/* - * double_rq_lock - safely lock two runqueues - * - * Note this does not disable interrupts like task_rq_lock, - * you need to do so manually before calling. - */ -static void double_rq_lock(struct rq *rq1, struct rq *rq2) - __acquires(rq1->lock) - __acquires(rq2->lock) -{ - BUG_ON(!irqs_disabled()); - if (rq1 == rq2) { - raw_spin_lock(&rq1->lock); - __acquire(rq2->lock); /* Fake it out ;) */ - } else { - if (rq1 < rq2) { - raw_spin_lock(&rq1->lock); - raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING); - } else { - raw_spin_lock(&rq2->lock); - raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING); - } - } - update_rq_clock(rq1); - update_rq_clock(rq2); -} - -/* - * double_rq_unlock - safely unlock two runqueues - * - * Note this does not restore interrupts like task_rq_unlock, - * you need to do so manually after calling. - */ -static void double_rq_unlock(struct rq *rq1, struct rq *rq2) - __releases(rq1->lock) - __releases(rq2->lock) -{ - raw_spin_unlock(&rq1->lock); - if (rq1 != rq2) - raw_spin_unlock(&rq2->lock); - else - __release(rq2->lock); -} - /* * sched_exec - execve() is a valuable balancing opportunity, because at * this point the task has the smallest effective memory and cache footprint. @@ -3179,1771 +3183,6 @@ again: task_rq_unlock(rq, &flags); } -/* - * pull_task - move a task from a remote runqueue to the local runqueue. - * Both runqueues must be locked. - */ -static void pull_task(struct rq *src_rq, struct task_struct *p, - struct rq *this_rq, int this_cpu) -{ - deactivate_task(src_rq, p, 0); - set_task_cpu(p, this_cpu); - activate_task(this_rq, p, 0); - check_preempt_curr(this_rq, p, 0); -} - -/* - * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? - */ -static -int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned) -{ - int tsk_cache_hot = 0; - /* - * We do not migrate tasks that are: - * 1) running (obviously), or - * 2) cannot be migrated to this CPU due to cpus_allowed, or - * 3) are cache-hot on their current CPU. - */ - if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) { - schedstat_inc(p, se.nr_failed_migrations_affine); - return 0; - } - *all_pinned = 0; - - if (task_running(rq, p)) { - schedstat_inc(p, se.nr_failed_migrations_running); - return 0; - } - - /* - * Aggressive migration if: - * 1) task is cache cold, or - * 2) too many balance attempts have failed. - */ - - tsk_cache_hot = task_hot(p, rq->clock, sd); - if (!tsk_cache_hot || - sd->nr_balance_failed > sd->cache_nice_tries) { -#ifdef CONFIG_SCHEDSTATS - if (tsk_cache_hot) { - schedstat_inc(sd, lb_hot_gained[idle]); - schedstat_inc(p, se.nr_forced_migrations); - } -#endif - return 1; - } - - if (tsk_cache_hot) { - schedstat_inc(p, se.nr_failed_migrations_hot); - return 0; - } - return 1; -} - -static unsigned long -balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, struct sched_domain *sd, - enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct rq_iterator *iterator) -{ - int loops = 0, pulled = 0, pinned = 0; - struct task_struct *p; - long rem_load_move = max_load_move; - - if (max_load_move == 0) - goto out; - - pinned = 1; - - /* - * Start the load-balancing iterator: - */ - p = iterator->start(iterator->arg); -next: - if (!p || loops++ > sysctl_sched_nr_migrate) - goto out; - - if ((p->se.load.weight >> 1) > rem_load_move || - !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { - p = iterator->next(iterator->arg); - goto next; - } - - pull_task(busiest, p, this_rq, this_cpu); - pulled++; - rem_load_move -= p->se.load.weight; - -#ifdef CONFIG_PREEMPT - /* - * NEWIDLE balancing is a source of latency, so preemptible kernels - * will stop after the first task is pulled to minimize the critical - * section. - */ - if (idle == CPU_NEWLY_IDLE) - goto out; -#endif - - /* - * We only want to steal up to the prescribed amount of weighted load. - */ - if (rem_load_move > 0) { - if (p->prio < *this_best_prio) - *this_best_prio = p->prio; - p = iterator->next(iterator->arg); - goto next; - } -out: - /* - * Right now, this is one of only two places pull_task() is called, - * so we can safely collect pull_task() stats here rather than - * inside pull_task(). - */ - schedstat_add(sd, lb_gained[idle], pulled); - - if (all_pinned) - *all_pinned = pinned; - - return max_load_move - rem_load_move; -} - -/* - * move_tasks tries to move up to max_load_move weighted load from busiest to - * this_rq, as part of a balancing operation within domain "sd". - * Returns 1 if successful and 0 otherwise. - * - * Called with both runqueues locked. - */ -static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned) -{ - const struct sched_class *class = sched_class_highest; - unsigned long total_load_moved = 0; - int this_best_prio = this_rq->curr->prio; - - do { - total_load_moved += - class->load_balance(this_rq, this_cpu, busiest, - max_load_move - total_load_moved, - sd, idle, all_pinned, &this_best_prio); - class = class->next; - -#ifdef CONFIG_PREEMPT - /* - * NEWIDLE balancing is a source of latency, so preemptible - * kernels will stop after the first task is pulled to minimize - * the critical section. - */ - if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) - break; -#endif - } while (class && max_load_move > total_load_moved); - - return total_load_moved > 0; -} - -static int -iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle, - struct rq_iterator *iterator) -{ - struct task_struct *p = iterator->start(iterator->arg); - int pinned = 0; - - while (p) { - if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { - pull_task(busiest, p, this_rq, this_cpu); - /* - * Right now, this is only the second place pull_task() - * is called, so we can safely collect pull_task() - * stats here rather than inside pull_task(). - */ - schedstat_inc(sd, lb_gained[idle]); - - return 1; - } - p = iterator->next(iterator->arg); - } - - return 0; -} - -/* - * move_one_task tries to move exactly one task from busiest to this_rq, as - * part of active balancing operations within "domain". - * Returns 1 if successful and 0 otherwise. - * - * Called with both runqueues locked. - */ -static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) -{ - const struct sched_class *class; - - for_each_class(class) { - if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) - return 1; - } - - return 0; -} -/********** Helpers for find_busiest_group ************************/ -/* - * sd_lb_stats - Structure to store the statistics of a sched_domain - * during load balancing. - */ -struct sd_lb_stats { - struct sched_group *busiest; /* Busiest group in this sd */ - struct sched_group *this; /* Local group in this sd */ - unsigned long total_load; /* Total load of all groups in sd */ - unsigned long total_pwr; /* Total power of all groups in sd */ - unsigned long avg_load; /* Average load across all groups in sd */ - - /** Statistics of this group */ - unsigned long this_load; - unsigned long this_load_per_task; - unsigned long this_nr_running; - - /* Statistics of the busiest group */ - unsigned long max_load; - unsigned long busiest_load_per_task; - unsigned long busiest_nr_running; - - int group_imb; /* Is there imbalance in this sd */ -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) - int power_savings_balance; /* Is powersave balance needed for this sd */ - struct sched_group *group_min; /* Least loaded group in sd */ - struct sched_group *group_leader; /* Group which relieves group_min */ - unsigned long min_load_per_task; /* load_per_task in group_min */ - unsigned long leader_nr_running; /* Nr running of group_leader */ - unsigned long min_nr_running; /* Nr running of group_min */ -#endif -}; - -/* - * sg_lb_stats - stats of a sched_group required for load_balancing - */ -struct sg_lb_stats { - unsigned long avg_load; /*Avg load across the CPUs of the group */ - unsigned long group_load; /* Total load over the CPUs of the group */ - unsigned long sum_nr_running; /* Nr tasks running in the group */ - unsigned long sum_weighted_load; /* Weighted load of group's tasks */ - unsigned long group_capacity; - int group_imb; /* Is there an imbalance in the group ? */ -}; - -/** - * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. - * @group: The group whose first cpu is to be returned. - */ -static inline unsigned int group_first_cpu(struct sched_group *group) -{ - return cpumask_first(sched_group_cpus(group)); -} - -/** - * get_sd_load_idx - Obtain the load index for a given sched domain. - * @sd: The sched_domain whose load_idx is to be obtained. - * @idle: The Idle status of the CPU for whose sd load_icx is obtained. - */ -static inline int get_sd_load_idx(struct sched_domain *sd, - enum cpu_idle_type idle) -{ - int load_idx; - - switch (idle) { - case CPU_NOT_IDLE: - load_idx = sd->busy_idx; - break; - - case CPU_NEWLY_IDLE: - load_idx = sd->newidle_idx; - break; - default: - load_idx = sd->idle_idx; - break; - } - - return load_idx; -} - - -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) -/** - * init_sd_power_savings_stats - Initialize power savings statistics for - * the given sched_domain, during load balancing. - * - * @sd: Sched domain whose power-savings statistics are to be initialized. - * @sds: Variable containing the statistics for sd. - * @idle: Idle status of the CPU at which we're performing load-balancing. - */ -static inline void init_sd_power_savings_stats(struct sched_domain *sd, - struct sd_lb_stats *sds, enum cpu_idle_type idle) -{ - /* - * Busy processors will not participate in power savings - * balance. - */ - if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) - sds->power_savings_balance = 0; - else { - sds->power_savings_balance = 1; - sds->min_nr_running = ULONG_MAX; - sds->leader_nr_running = 0; - } -} - -/** - * update_sd_power_savings_stats - Update the power saving stats for a - * sched_domain while performing load balancing. - * - * @group: sched_group belonging to the sched_domain under consideration. - * @sds: Variable containing the statistics of the sched_domain - * @local_group: Does group contain the CPU for which we're performing - * load balancing ? - * @sgs: Variable containing the statistics of the group. - */ -static inline void update_sd_power_savings_stats(struct sched_group *group, - struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) -{ - - if (!sds->power_savings_balance) - return; - - /* - * If the local group is idle or completely loaded - * no need to do power savings balance at this domain - */ - if (local_group && (sds->this_nr_running >= sgs->group_capacity || - !sds->this_nr_running)) - sds->power_savings_balance = 0; - - /* - * If a group is already running at full capacity or idle, - * don't include that group in power savings calculations - */ - if (!sds->power_savings_balance || - sgs->sum_nr_running >= sgs->group_capacity || - !sgs->sum_nr_running) - return; - - /* - * Calculate the group which has the least non-idle load. - * This is the group from where we need to pick up the load - * for saving power - */ - if ((sgs->sum_nr_running < sds->min_nr_running) || - (sgs->sum_nr_running == sds->min_nr_running && - group_first_cpu(group) > group_first_cpu(sds->group_min))) { - sds->group_min = group; - sds->min_nr_running = sgs->sum_nr_running; - sds->min_load_per_task = sgs->sum_weighted_load / - sgs->sum_nr_running; - } - - /* - * Calculate the group which is almost near its - * capacity but still has some space to pick up some load - * from other group and save more power - */ - if (sgs->sum_nr_running + 1 > sgs->group_capacity) - return; - - if (sgs->sum_nr_running > sds->leader_nr_running || - (sgs->sum_nr_running == sds->leader_nr_running && - group_first_cpu(group) < group_first_cpu(sds->group_leader))) { - sds->group_leader = group; - sds->leader_nr_running = sgs->sum_nr_running; - } -} - -/** - * check_power_save_busiest_group - see if there is potential for some power-savings balance - * @sds: Variable containing the statistics of the sched_domain - * under consideration. - * @this_cpu: Cpu at which we're currently performing load-balancing. - * @imbalance: Variable to store the imbalance. - * - * Description: - * Check if we have potential to perform some power-savings balance. - * If yes, set the busiest group to be the least loaded group in the - * sched_domain, so that it's CPUs can be put to idle. - * - * Returns 1 if there is potential to perform power-savings balance. - * Else returns 0. - */ -static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, - int this_cpu, unsigned long *imbalance) -{ - if (!sds->power_savings_balance) - return 0; - - if (sds->this != sds->group_leader || - sds->group_leader == sds->group_min) - return 0; - - *imbalance = sds->min_load_per_task; - sds->busiest = sds->group_min; - - return 1; - -} -#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ -static inline void init_sd_power_savings_stats(struct sched_domain *sd, - struct sd_lb_stats *sds, enum cpu_idle_type idle) -{ - return; -} - -static inline void update_sd_power_savings_stats(struct sched_group *group, - struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) -{ - return; -} - -static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, - int this_cpu, unsigned long *imbalance) -{ - return 0; -} -#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ - - -unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) -{ - return SCHED_LOAD_SCALE; -} - -unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) -{ - return default_scale_freq_power(sd, cpu); -} - -unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) -{ - unsigned long weight = cpumask_weight(sched_domain_span(sd)); - unsigned long smt_gain = sd->smt_gain; - - smt_gain /= weight; - - return smt_gain; -} - -unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) -{ - return default_scale_smt_power(sd, cpu); -} - -unsigned long scale_rt_power(int cpu) -{ - struct rq *rq = cpu_rq(cpu); - u64 total, available; - - sched_avg_update(rq); - - total = sched_avg_period() + (rq->clock - rq->age_stamp); - available = total - rq->rt_avg; - - if (unlikely((s64)total < SCHED_LOAD_SCALE)) - total = SCHED_LOAD_SCALE; - - total >>= SCHED_LOAD_SHIFT; - - return div_u64(available, total); -} - -static void update_cpu_power(struct sched_domain *sd, int cpu) -{ - unsigned long weight = cpumask_weight(sched_domain_span(sd)); - unsigned long power = SCHED_LOAD_SCALE; - struct sched_group *sdg = sd->groups; - - if (sched_feat(ARCH_POWER)) - power *= arch_scale_freq_power(sd, cpu); - else - power *= default_scale_freq_power(sd, cpu); - - power >>= SCHED_LOAD_SHIFT; - - if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { - if (sched_feat(ARCH_POWER)) - power *= arch_scale_smt_power(sd, cpu); - else - power *= default_scale_smt_power(sd, cpu); - - power >>= SCHED_LOAD_SHIFT; - } - - power *= scale_rt_power(cpu); - power >>= SCHED_LOAD_SHIFT; - - if (!power) - power = 1; - - sdg->cpu_power = power; -} - -static void update_group_power(struct sched_domain *sd, int cpu) -{ - struct sched_domain *child = sd->child; - struct sched_group *group, *sdg = sd->groups; - unsigned long power; - - if (!child) { - update_cpu_power(sd, cpu); - return; - } - - power = 0; - - group = child->groups; - do { - power += group->cpu_power; - group = group->next; - } while (group != child->groups); - - sdg->cpu_power = power; -} - -/** - * update_sg_lb_stats - Update sched_group's statistics for load balancing. - * @sd: The sched_domain whose statistics are to be updated. - * @group: sched_group whose statistics are to be updated. - * @this_cpu: Cpu for which load balance is currently performed. - * @idle: Idle status of this_cpu - * @load_idx: Load index of sched_domain of this_cpu for load calc. - * @sd_idle: Idle status of the sched_domain containing group. - * @local_group: Does group contain this_cpu. - * @cpus: Set of cpus considered for load balancing. - * @balance: Should we balance. - * @sgs: variable to hold the statistics for this group. - */ -static inline void update_sg_lb_stats(struct sched_domain *sd, - struct sched_group *group, int this_cpu, - enum cpu_idle_type idle, int load_idx, int *sd_idle, - int local_group, const struct cpumask *cpus, - int *balance, struct sg_lb_stats *sgs) -{ - unsigned long load, max_cpu_load, min_cpu_load; - int i; - unsigned int balance_cpu = -1, first_idle_cpu = 0; - unsigned long sum_avg_load_per_task; - unsigned long avg_load_per_task; - - if (local_group) { - balance_cpu = group_first_cpu(group); - if (balance_cpu == this_cpu) - update_group_power(sd, this_cpu); - } - - /* Tally up the load of all CPUs in the group */ - sum_avg_load_per_task = avg_load_per_task = 0; - max_cpu_load = 0; - min_cpu_load = ~0UL; - - for_each_cpu_and(i, sched_group_cpus(group), cpus) { - struct rq *rq = cpu_rq(i); - - if (*sd_idle && rq->nr_running) - *sd_idle = 0; - - /* Bias balancing toward cpus of our domain */ - if (local_group) { - if (idle_cpu(i) && !first_idle_cpu) { - first_idle_cpu = 1; - balance_cpu = i; - } - - load = target_load(i, load_idx); - } else { - load = source_load(i, load_idx); - if (load > max_cpu_load) - max_cpu_load = load; - if (min_cpu_load > load) - min_cpu_load = load; - } - - sgs->group_load += load; - sgs->sum_nr_running += rq->nr_running; - sgs->sum_weighted_load += weighted_cpuload(i); - - sum_avg_load_per_task += cpu_avg_load_per_task(i); - } - - /* - * First idle cpu or the first cpu(busiest) in this sched group - * is eligible for doing load balancing at this and above - * domains. In the newly idle case, we will allow all the cpu's - * to do the newly idle load balance. - */ - if (idle != CPU_NEWLY_IDLE && local_group && - balance_cpu != this_cpu && balance) { - *balance = 0; - return; - } - - /* Adjust by relative CPU power of the group */ - sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; - - - /* - * Consider the group unbalanced when the imbalance is larger - * than the average weight of two tasks. - * - * APZ: with cgroup the avg task weight can vary wildly and - * might not be a suitable number - should we keep a - * normalized nr_running number somewhere that negates - * the hierarchy? - */ - avg_load_per_task = (sum_avg_load_per_task * SCHED_LOAD_SCALE) / - group->cpu_power; - - if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) - sgs->group_imb = 1; - - sgs->group_capacity = - DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE); -} - -/** - * update_sd_lb_stats - Update sched_group's statistics for load balancing. - * @sd: sched_domain whose statistics are to be updated. - * @this_cpu: Cpu for which load balance is currently performed. - * @idle: Idle status of this_cpu - * @sd_idle: Idle status of the sched_domain containing group. - * @cpus: Set of cpus considered for load balancing. - * @balance: Should we balance. - * @sds: variable to hold the statistics for this sched_domain. - */ -static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, - enum cpu_idle_type idle, int *sd_idle, - const struct cpumask *cpus, int *balance, - struct sd_lb_stats *sds) -{ - struct sched_domain *child = sd->child; - struct sched_group *group = sd->groups; - struct sg_lb_stats sgs; - int load_idx, prefer_sibling = 0; - - if (child && child->flags & SD_PREFER_SIBLING) - prefer_sibling = 1; - - init_sd_power_savings_stats(sd, sds, idle); - load_idx = get_sd_load_idx(sd, idle); - - do { - int local_group; - - local_group = cpumask_test_cpu(this_cpu, - sched_group_cpus(group)); - memset(&sgs, 0, sizeof(sgs)); - update_sg_lb_stats(sd, group, this_cpu, idle, load_idx, sd_idle, - local_group, cpus, balance, &sgs); - - if (local_group && balance && !(*balance)) - return; - - sds->total_load += sgs.group_load; - sds->total_pwr += group->cpu_power; - - /* - * In case the child domain prefers tasks go to siblings - * first, lower the group capacity to one so that we'll try - * and move all the excess tasks away. - */ - if (prefer_sibling) - sgs.group_capacity = min(sgs.group_capacity, 1UL); - - if (local_group) { - sds->this_load = sgs.avg_load; - sds->this = group; - sds->this_nr_running = sgs.sum_nr_running; - sds->this_load_per_task = sgs.sum_weighted_load; - } else if (sgs.avg_load > sds->max_load && - (sgs.sum_nr_running > sgs.group_capacity || - sgs.group_imb)) { - sds->max_load = sgs.avg_load; - sds->busiest = group; - sds->busiest_nr_running = sgs.sum_nr_running; - sds->busiest_load_per_task = sgs.sum_weighted_load; - sds->group_imb = sgs.group_imb; - } - - update_sd_power_savings_stats(group, sds, local_group, &sgs); - group = group->next; - } while (group != sd->groups); -} - -/** - * fix_small_imbalance - Calculate the minor imbalance that exists - * amongst the groups of a sched_domain, during - * load balancing. - * @sds: Statistics of the sched_domain whose imbalance is to be calculated. - * @this_cpu: The cpu at whose sched_domain we're performing load-balance. - * @imbalance: Variable to store the imbalance. - */ -static inline void fix_small_imbalance(struct sd_lb_stats *sds, - int this_cpu, unsigned long *imbalance) -{ - unsigned long tmp, pwr_now = 0, pwr_move = 0; - unsigned int imbn = 2; - - if (sds->this_nr_running) { - sds->this_load_per_task /= sds->this_nr_running; - if (sds->busiest_load_per_task > - sds->this_load_per_task) - imbn = 1; - } else - sds->this_load_per_task = - cpu_avg_load_per_task(this_cpu); - - if (sds->max_load - sds->this_load + sds->busiest_load_per_task >= - sds->busiest_load_per_task * imbn) { - *imbalance = sds->busiest_load_per_task; - return; - } - - /* - * OK, we don't have enough imbalance to justify moving tasks, - * however we may be able to increase total CPU power used by - * moving them. - */ - - pwr_now += sds->busiest->cpu_power * - min(sds->busiest_load_per_task, sds->max_load); - pwr_now += sds->this->cpu_power * - min(sds->this_load_per_task, sds->this_load); - pwr_now /= SCHED_LOAD_SCALE; - - /* Amount of load we'd subtract */ - tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / - sds->busiest->cpu_power; - if (sds->max_load > tmp) - pwr_move += sds->busiest->cpu_power * - min(sds->busiest_load_per_task, sds->max_load - tmp); - - /* Amount of load we'd add */ - if (sds->max_load * sds->busiest->cpu_power < - sds->busiest_load_per_task * SCHED_LOAD_SCALE) - tmp = (sds->max_load * sds->busiest->cpu_power) / - sds->this->cpu_power; - else - tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / - sds->this->cpu_power; - pwr_move += sds->this->cpu_power * - min(sds->this_load_per_task, sds->this_load + tmp); - pwr_move /= SCHED_LOAD_SCALE; - - /* Move if we gain throughput */ - if (pwr_move > pwr_now) - *imbalance = sds->busiest_load_per_task; -} - -/** - * calculate_imbalance - Calculate the amount of imbalance present within the - * groups of a given sched_domain during load balance. - * @sds: statistics of the sched_domain whose imbalance is to be calculated. - * @this_cpu: Cpu for which currently load balance is being performed. - * @imbalance: The variable to store the imbalance. - */ -static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, - unsigned long *imbalance) -{ - unsigned long max_pull; - /* - * In the presence of smp nice balancing, certain scenarios can have - * max load less than avg load(as we skip the groups at or below - * its cpu_power, while calculating max_load..) - */ - if (sds->max_load < sds->avg_load) { - *imbalance = 0; - return fix_small_imbalance(sds, this_cpu, imbalance); - } - - /* Don't want to pull so many tasks that a group would go idle */ - max_pull = min(sds->max_load - sds->avg_load, - sds->max_load - sds->busiest_load_per_task); - - /* How much load to actually move to equalise the imbalance */ - *imbalance = min(max_pull * sds->busiest->cpu_power, - (sds->avg_load - sds->this_load) * sds->this->cpu_power) - / SCHED_LOAD_SCALE; - - /* - * if *imbalance is less than the average load per runnable task - * there is no gaurantee that any tasks will be moved so we'll have - * a think about bumping its value to force at least one task to be - * moved - */ - if (*imbalance < sds->busiest_load_per_task) - return fix_small_imbalance(sds, this_cpu, imbalance); - -} -/******* find_busiest_group() helpers end here *********************/ - -/** - * find_busiest_group - Returns the busiest group within the sched_domain - * if there is an imbalance. If there isn't an imbalance, and - * the user has opted for power-savings, it returns a group whose - * CPUs can be put to idle by rebalancing those tasks elsewhere, if - * such a group exists. - * - * Also calculates the amount of weighted load which should be moved - * to restore balance. - * - * @sd: The sched_domain whose busiest group is to be returned. - * @this_cpu: The cpu for which load balancing is currently being performed. - * @imbalance: Variable which stores amount of weighted load which should - * be moved to restore balance/put a group to idle. - * @idle: The idle status of this_cpu. - * @sd_idle: The idleness of sd - * @cpus: The set of CPUs under consideration for load-balancing. - * @balance: Pointer to a variable indicating if this_cpu - * is the appropriate cpu to perform load balancing at this_level. - * - * Returns: - the busiest group if imbalance exists. - * - If no imbalance and user has opted for power-savings balance, - * return the least loaded group whose CPUs can be - * put to idle by rebalancing its tasks onto our group. - */ -static struct sched_group * -find_busiest_group(struct sched_domain *sd, int this_cpu, - unsigned long *imbalance, enum cpu_idle_type idle, - int *sd_idle, const struct cpumask *cpus, int *balance) -{ - struct sd_lb_stats sds; - - memset(&sds, 0, sizeof(sds)); - - /* - * Compute the various statistics relavent for load balancing at - * this level. - */ - update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus, - balance, &sds); - - /* Cases where imbalance does not exist from POV of this_cpu */ - /* 1) this_cpu is not the appropriate cpu to perform load balancing - * at this level. - * 2) There is no busy sibling group to pull from. - * 3) This group is the busiest group. - * 4) This group is more busy than the avg busieness at this - * sched_domain. - * 5) The imbalance is within the specified limit. - * 6) Any rebalance would lead to ping-pong - */ - if (balance && !(*balance)) - goto ret; - - if (!sds.busiest || sds.busiest_nr_running == 0) - goto out_balanced; - - if (sds.this_load >= sds.max_load) - goto out_balanced; - - sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; - - if (sds.this_load >= sds.avg_load) - goto out_balanced; - - if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) - goto out_balanced; - - sds.busiest_load_per_task /= sds.busiest_nr_running; - if (sds.group_imb) - sds.busiest_load_per_task = - min(sds.busiest_load_per_task, sds.avg_load); - - /* - * We're trying to get all the cpus to the average_load, so we don't - * want to push ourselves above the average load, nor do we wish to - * reduce the max loaded cpu below the average load, as either of these - * actions would just result in more rebalancing later, and ping-pong - * tasks around. Thus we look for the minimum possible imbalance. - * Negative imbalances (*we* are more loaded than anyone else) will - * be counted as no imbalance for these purposes -- we can't fix that - * by pulling tasks to us. Be careful of negative numbers as they'll - * appear as very large values with unsigned longs. - */ - if (sds.max_load <= sds.busiest_load_per_task) - goto out_balanced; - - /* Looks like there is an imbalance. Compute it */ - calculate_imbalance(&sds, this_cpu, imbalance); - return sds.busiest; - -out_balanced: - /* - * There is no obvious imbalance. But check if we can do some balancing - * to save power. - */ - if (check_power_save_busiest_group(&sds, this_cpu, imbalance)) - return sds.busiest; -ret: - *imbalance = 0; - return NULL; -} - -/* - * find_busiest_queue - find the busiest runqueue among the cpus in group. - */ -static struct rq * -find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, - unsigned long imbalance, const struct cpumask *cpus) -{ - struct rq *busiest = NULL, *rq; - unsigned long max_load = 0; - int i; - - for_each_cpu(i, sched_group_cpus(group)) { - unsigned long power = power_of(i); - unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); - unsigned long wl; - - if (!cpumask_test_cpu(i, cpus)) - continue; - - rq = cpu_rq(i); - wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; - wl /= power; - - if (capacity && rq->nr_running == 1 && wl > imbalance) - continue; - - if (wl > max_load) { - max_load = wl; - busiest = rq; - } - } - - return busiest; -} - -/* - * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but - * so long as it is large enough. - */ -#define MAX_PINNED_INTERVAL 512 - -/* Working cpumask for load_balance and load_balance_newidle. */ -static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); - -/* - * Check this_cpu to ensure it is balanced within domain. Attempt to move - * tasks if there is an imbalance. - */ -static int load_balance(int this_cpu, struct rq *this_rq, - struct sched_domain *sd, enum cpu_idle_type idle, - int *balance) -{ - int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; - struct sched_group *group; - unsigned long imbalance; - struct rq *busiest; - unsigned long flags; - struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); - - cpumask_copy(cpus, cpu_active_mask); - - /* - * When power savings policy is enabled for the parent domain, idle - * sibling can pick up load irrespective of busy siblings. In this case, - * let the state of idle sibling percolate up as CPU_IDLE, instead of - * portraying it as CPU_NOT_IDLE. - */ - if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - sd_idle = 1; - - schedstat_inc(sd, lb_count[idle]); - -redo: - update_shares(sd); - group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, - cpus, balance); - - if (*balance == 0) - goto out_balanced; - - if (!group) { - schedstat_inc(sd, lb_nobusyg[idle]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, idle, imbalance, cpus); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[idle]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[idle], imbalance); - - ld_moved = 0; - if (busiest->nr_running > 1) { - /* - * Attempt to move tasks. If find_busiest_group has found - * an imbalance but busiest->nr_running <= 1, the group is - * still unbalanced. ld_moved simply stays zero, so it is - * correctly treated as an imbalance. - */ - local_irq_save(flags); - double_rq_lock(this_rq, busiest); - ld_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, idle, &all_pinned); - double_rq_unlock(this_rq, busiest); - local_irq_restore(flags); - - /* - * some other cpu did the load balance for us. - */ - if (ld_moved && this_cpu != smp_processor_id()) - resched_cpu(this_cpu); - - /* All tasks on this runqueue were pinned by CPU affinity */ - if (unlikely(all_pinned)) { - cpumask_clear_cpu(cpu_of(busiest), cpus); - if (!cpumask_empty(cpus)) - goto redo; - goto out_balanced; - } - } - - if (!ld_moved) { - schedstat_inc(sd, lb_failed[idle]); - sd->nr_balance_failed++; - - if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { - - raw_spin_lock_irqsave(&busiest->lock, flags); - - /* don't kick the migration_thread, if the curr - * task on busiest cpu can't be moved to this_cpu - */ - if (!cpumask_test_cpu(this_cpu, - &busiest->curr->cpus_allowed)) { - raw_spin_unlock_irqrestore(&busiest->lock, - flags); - all_pinned = 1; - goto out_one_pinned; - } - - if (!busiest->active_balance) { - busiest->active_balance = 1; - busiest->push_cpu = this_cpu; - active_balance = 1; - } - raw_spin_unlock_irqrestore(&busiest->lock, flags); - if (active_balance) - wake_up_process(busiest->migration_thread); - - /* - * We've kicked active balancing, reset the failure - * counter. - */ - sd->nr_balance_failed = sd->cache_nice_tries+1; - } - } else - sd->nr_balance_failed = 0; - - if (likely(!active_balance)) { - /* We were unbalanced, so reset the balancing interval */ - sd->balance_interval = sd->min_interval; - } else { - /* - * If we've begun active balancing, start to back off. This - * case may not be covered by the all_pinned logic if there - * is only 1 task on the busy runqueue (because we don't call - * move_tasks). - */ - if (sd->balance_interval < sd->max_interval) - sd->balance_interval *= 2; - } - - if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - ld_moved = -1; - - goto out; - -out_balanced: - schedstat_inc(sd, lb_balanced[idle]); - - sd->nr_balance_failed = 0; - -out_one_pinned: - /* tune up the balancing interval */ - if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || - (sd->balance_interval < sd->max_interval)) - sd->balance_interval *= 2; - - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - ld_moved = -1; - else - ld_moved = 0; -out: - if (ld_moved) - update_shares(sd); - return ld_moved; -} - -/* - * Check this_cpu to ensure it is balanced within domain. Attempt to move - * tasks if there is an imbalance. - * - * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). - * this_rq is locked. - */ -static int -load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) -{ - struct sched_group *group; - struct rq *busiest = NULL; - unsigned long imbalance; - int ld_moved = 0; - int sd_idle = 0; - int all_pinned = 0; - struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); - - cpumask_copy(cpus, cpu_active_mask); - - /* - * When power savings policy is enabled for the parent domain, idle - * sibling can pick up load irrespective of busy siblings. In this case, - * let the state of idle sibling percolate up as IDLE, instead of - * portraying it as CPU_NOT_IDLE. - */ - if (sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - sd_idle = 1; - - schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); -redo: - update_shares_locked(this_rq, sd); - group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, - &sd_idle, cpus, NULL); - if (!group) { - schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); - - ld_moved = 0; - if (busiest->nr_running > 1) { - /* Attempt to move tasks */ - double_lock_balance(this_rq, busiest); - /* this_rq->clock is already updated */ - update_rq_clock(busiest); - ld_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, CPU_NEWLY_IDLE, - &all_pinned); - double_unlock_balance(this_rq, busiest); - - if (unlikely(all_pinned)) { - cpumask_clear_cpu(cpu_of(busiest), cpus); - if (!cpumask_empty(cpus)) - goto redo; - } - } - - if (!ld_moved) { - int active_balance = 0; - - schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - - if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) - return -1; - - if (sd->nr_balance_failed++ < 2) - return -1; - - /* - * The only task running in a non-idle cpu can be moved to this - * cpu in an attempt to completely freeup the other CPU - * package. The same method used to move task in load_balance() - * have been extended for load_balance_newidle() to speedup - * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2) - * - * The package power saving logic comes from - * find_busiest_group(). If there are no imbalance, then - * f_b_g() will return NULL. However when sched_mc={1,2} then - * f_b_g() will select a group from which a running task may be - * pulled to this cpu in order to make the other package idle. - * If there is no opportunity to make a package idle and if - * there are no imbalance, then f_b_g() will return NULL and no - * action will be taken in load_balance_newidle(). - * - * Under normal task pull operation due to imbalance, there - * will be more than one task in the source run queue and - * move_tasks() will succeed. ld_moved will be true and this - * active balance code will not be triggered. - */ - - /* Lock busiest in correct order while this_rq is held */ - double_lock_balance(this_rq, busiest); - - /* - * don't kick the migration_thread, if the curr - * task on busiest cpu can't be moved to this_cpu - */ - if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) { - double_unlock_balance(this_rq, busiest); - all_pinned = 1; - return ld_moved; - } - - if (!busiest->active_balance) { - busiest->active_balance = 1; - busiest->push_cpu = this_cpu; - active_balance = 1; - } - - double_unlock_balance(this_rq, busiest); - /* - * Should not call ttwu while holding a rq->lock - */ - raw_spin_unlock(&this_rq->lock); - if (active_balance) - wake_up_process(busiest->migration_thread); - raw_spin_lock(&this_rq->lock); - - } else - sd->nr_balance_failed = 0; - - update_shares_locked(this_rq, sd); - return ld_moved; - -out_balanced: - schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - sd->nr_balance_failed = 0; - - return 0; -} - -/* - * idle_balance is called by schedule() if this_cpu is about to become - * idle. Attempts to pull tasks from other CPUs. - */ -static void idle_balance(int this_cpu, struct rq *this_rq) -{ - struct sched_domain *sd; - int pulled_task = 0; - unsigned long next_balance = jiffies + HZ; - - this_rq->idle_stamp = this_rq->clock; - - if (this_rq->avg_idle < sysctl_sched_migration_cost) - return; - - for_each_domain(this_cpu, sd) { - unsigned long interval; - - if (!(sd->flags & SD_LOAD_BALANCE)) - continue; - - if (sd->flags & SD_BALANCE_NEWIDLE) - /* If we've pulled tasks over stop searching: */ - pulled_task = load_balance_newidle(this_cpu, this_rq, - sd); - - interval = msecs_to_jiffies(sd->balance_interval); - if (time_after(next_balance, sd->last_balance + interval)) - next_balance = sd->last_balance + interval; - if (pulled_task) { - this_rq->idle_stamp = 0; - break; - } - } - if (pulled_task || time_after(jiffies, this_rq->next_balance)) { - /* - * We are going idle. next_balance may be set based on - * a busy processor. So reset next_balance. - */ - this_rq->next_balance = next_balance; - } -} - -/* - * active_load_balance is run by migration threads. It pushes running tasks - * off the busiest CPU onto idle CPUs. It requires at least 1 task to be - * running on each physical CPU where possible, and avoids physical / - * logical imbalances. - * - * Called with busiest_rq locked. - */ -static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) -{ - int target_cpu = busiest_rq->push_cpu; - struct sched_domain *sd; - struct rq *target_rq; - - /* Is there any task to move? */ - if (busiest_rq->nr_running <= 1) - return; - - target_rq = cpu_rq(target_cpu); - - /* - * This condition is "impossible", if it occurs - * we need to fix it. Originally reported by - * Bjorn Helgaas on a 128-cpu setup. - */ - BUG_ON(busiest_rq == target_rq); - - /* move a task from busiest_rq to target_rq */ - double_lock_balance(busiest_rq, target_rq); - update_rq_clock(busiest_rq); - update_rq_clock(target_rq); - - /* Search for an sd spanning us and the target CPU. */ - for_each_domain(target_cpu, sd) { - if ((sd->flags & SD_LOAD_BALANCE) && - cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) - break; - } - - if (likely(sd)) { - schedstat_inc(sd, alb_count); - - if (move_one_task(target_rq, target_cpu, busiest_rq, - sd, CPU_IDLE)) - schedstat_inc(sd, alb_pushed); - else - schedstat_inc(sd, alb_failed); - } - double_unlock_balance(busiest_rq, target_rq); -} - -#ifdef CONFIG_NO_HZ -static struct { - atomic_t load_balancer; - cpumask_var_t cpu_mask; - cpumask_var_t ilb_grp_nohz_mask; -} nohz ____cacheline_aligned = { - .load_balancer = ATOMIC_INIT(-1), -}; - -int get_nohz_load_balancer(void) -{ - return atomic_read(&nohz.load_balancer); -} - -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) -/** - * lowest_flag_domain - Return lowest sched_domain containing flag. - * @cpu: The cpu whose lowest level of sched domain is to - * be returned. - * @flag: The flag to check for the lowest sched_domain - * for the given cpu. - * - * Returns the lowest sched_domain of a cpu which contains the given flag. - */ -static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) -{ - struct sched_domain *sd; - - for_each_domain(cpu, sd) - if (sd && (sd->flags & flag)) - break; - - return sd; -} - -/** - * for_each_flag_domain - Iterates over sched_domains containing the flag. - * @cpu: The cpu whose domains we're iterating over. - * @sd: variable holding the value of the power_savings_sd - * for cpu. - * @flag: The flag to filter the sched_domains to be iterated. - * - * Iterates over all the scheduler domains for a given cpu that has the 'flag' - * set, starting from the lowest sched_domain to the highest. - */ -#define for_each_flag_domain(cpu, sd, flag) \ - for (sd = lowest_flag_domain(cpu, flag); \ - (sd && (sd->flags & flag)); sd = sd->parent) - -/** - * is_semi_idle_group - Checks if the given sched_group is semi-idle. - * @ilb_group: group to be checked for semi-idleness - * - * Returns: 1 if the group is semi-idle. 0 otherwise. - * - * We define a sched_group to be semi idle if it has atleast one idle-CPU - * and atleast one non-idle CPU. This helper function checks if the given - * sched_group is semi-idle or not. - */ -static inline int is_semi_idle_group(struct sched_group *ilb_group) -{ - cpumask_and(nohz.ilb_grp_nohz_mask, nohz.cpu_mask, - sched_group_cpus(ilb_group)); - - /* - * A sched_group is semi-idle when it has atleast one busy cpu - * and atleast one idle cpu. - */ - if (cpumask_empty(nohz.ilb_grp_nohz_mask)) - return 0; - - if (cpumask_equal(nohz.ilb_grp_nohz_mask, sched_group_cpus(ilb_group))) - return 0; - - return 1; -} -/** - * find_new_ilb - Finds the optimum idle load balancer for nomination. - * @cpu: The cpu which is nominating a new idle_load_balancer. - * - * Returns: Returns the id of the idle load balancer if it exists, - * Else, returns >= nr_cpu_ids. - * - * This algorithm picks the idle load balancer such that it belongs to a - * semi-idle powersavings sched_domain. The idea is to try and avoid - * completely idle packages/cores just for the purpose of idle load balancing - * when there are other idle cpu's which are better suited for that job. - */ -static int find_new_ilb(int cpu) -{ - struct sched_domain *sd; - struct sched_group *ilb_group; - - /* - * Have idle load balancer selection from semi-idle packages only - * when power-aware load balancing is enabled - */ - if (!(sched_smt_power_savings || sched_mc_power_savings)) - goto out_done; - - /* - * Optimize for the case when we have no idle CPUs or only one - * idle CPU. Don't walk the sched_domain hierarchy in such cases - */ - if (cpumask_weight(nohz.cpu_mask) < 2) - goto out_done; - - for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { - ilb_group = sd->groups; - - do { - if (is_semi_idle_group(ilb_group)) - return cpumask_first(nohz.ilb_grp_nohz_mask); - - ilb_group = ilb_group->next; - - } while (ilb_group != sd->groups); - } - -out_done: - return cpumask_first(nohz.cpu_mask); -} -#else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ -static inline int find_new_ilb(int call_cpu) -{ - return cpumask_first(nohz.cpu_mask); -} -#endif - -/* - * This routine will try to nominate the ilb (idle load balancing) - * owner among the cpus whose ticks are stopped. ilb owner will do the idle - * load balancing on behalf of all those cpus. If all the cpus in the system - * go into this tickless mode, then there will be no ilb owner (as there is - * no need for one) and all the cpus will sleep till the next wakeup event - * arrives... - * - * For the ilb owner, tick is not stopped. And this tick will be used - * for idle load balancing. ilb owner will still be part of - * nohz.cpu_mask.. - * - * While stopping the tick, this cpu will become the ilb owner if there - * is no other owner. And will be the owner till that cpu becomes busy - * or if all cpus in the system stop their ticks at which point - * there is no need for ilb owner. - * - * When the ilb owner becomes busy, it nominates another owner, during the - * next busy scheduler_tick() - */ -int select_nohz_load_balancer(int stop_tick) -{ - int cpu = smp_processor_id(); - - if (stop_tick) { - cpu_rq(cpu)->in_nohz_recently = 1; - - if (!cpu_active(cpu)) { - if (atomic_read(&nohz.load_balancer) != cpu) - return 0; - - /* - * If we are going offline and still the leader, - * give up! - */ - if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) - BUG(); - - return 0; - } - - cpumask_set_cpu(cpu, nohz.cpu_mask); - - /* time for ilb owner also to sleep */ - if (cpumask_weight(nohz.cpu_mask) == num_active_cpus()) { - if (atomic_read(&nohz.load_balancer) == cpu) - atomic_set(&nohz.load_balancer, -1); - return 0; - } - - if (atomic_read(&nohz.load_balancer) == -1) { - /* make me the ilb owner */ - if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) - return 1; - } else if (atomic_read(&nohz.load_balancer) == cpu) { - int new_ilb; - - if (!(sched_smt_power_savings || - sched_mc_power_savings)) - return 1; - /* - * Check to see if there is a more power-efficient - * ilb. - */ - new_ilb = find_new_ilb(cpu); - if (new_ilb < nr_cpu_ids && new_ilb != cpu) { - atomic_set(&nohz.load_balancer, -1); - resched_cpu(new_ilb); - return 0; - } - return 1; - } - } else { - if (!cpumask_test_cpu(cpu, nohz.cpu_mask)) - return 0; - - cpumask_clear_cpu(cpu, nohz.cpu_mask); - - if (atomic_read(&nohz.load_balancer) == cpu) - if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) - BUG(); - } - return 0; -} -#endif - -static DEFINE_SPINLOCK(balancing); - -/* - * It checks each scheduling domain to see if it is due to be balanced, - * and initiates a balancing operation if so. - * - * Balancing parameters are set up in arch_init_sched_domains. - */ -static void rebalance_domains(int cpu, enum cpu_idle_type idle) -{ - int balance = 1; - struct rq *rq = cpu_rq(cpu); - unsigned long interval; - struct sched_domain *sd; - /* Earliest time when we have to do rebalance again */ - unsigned long next_balance = jiffies + 60*HZ; - int update_next_balance = 0; - int need_serialize; - - for_each_domain(cpu, sd) { - if (!(sd->flags & SD_LOAD_BALANCE)) - continue; - - interval = sd->balance_interval; - if (idle != CPU_IDLE) - interval *= sd->busy_factor; - - /* scale ms to jiffies */ - interval = msecs_to_jiffies(interval); - if (unlikely(!interval)) - interval = 1; - if (interval > HZ*NR_CPUS/10) - interval = HZ*NR_CPUS/10; - - need_serialize = sd->flags & SD_SERIALIZE; - - if (need_serialize) { - if (!spin_trylock(&balancing)) - goto out; - } - - if (time_after_eq(jiffies, sd->last_balance + interval)) { - if (load_balance(cpu, rq, sd, idle, &balance)) { - /* - * We've pulled tasks over so either we're no - * longer idle, or one of our SMT siblings is - * not idle. - */ - idle = CPU_NOT_IDLE; - } - sd->last_balance = jiffies; - } - if (need_serialize) - spin_unlock(&balancing); -out: - if (time_after(next_balance, sd->last_balance + interval)) { - next_balance = sd->last_balance + interval; - update_next_balance = 1; - } - - /* - * Stop the load balance at this level. There is another - * CPU in our sched group which is doing load balancing more - * actively. - */ - if (!balance) - break; - } - - /* - * next_balance will be updated only when there is a need. - * When the cpu is attached to null domain for ex, it will not be - * updated. - */ - if (likely(update_next_balance)) - rq->next_balance = next_balance; -} - -/* - * run_rebalance_domains is triggered when needed from the scheduler tick. - * In CONFIG_NO_HZ case, the idle load balance owner will do the - * rebalancing for all the cpus for whom scheduler ticks are stopped. - */ -static void run_rebalance_domains(struct softirq_action *h) -{ - int this_cpu = smp_processor_id(); - struct rq *this_rq = cpu_rq(this_cpu); - enum cpu_idle_type idle = this_rq->idle_at_tick ? - CPU_IDLE : CPU_NOT_IDLE; - - rebalance_domains(this_cpu, idle); - -#ifdef CONFIG_NO_HZ - /* - * If this cpu is the owner for idle load balancing, then do the - * balancing on behalf of the other idle cpus whose ticks are - * stopped. - */ - if (this_rq->idle_at_tick && - atomic_read(&nohz.load_balancer) == this_cpu) { - struct rq *rq; - int balance_cpu; - - for_each_cpu(balance_cpu, nohz.cpu_mask) { - if (balance_cpu == this_cpu) - continue; - - /* - * If this cpu gets work to do, stop the load balancing - * work being done for other cpus. Next load - * balancing owner will pick it up. - */ - if (need_resched()) - break; - - rebalance_domains(balance_cpu, CPU_IDLE); - - rq = cpu_rq(balance_cpu); - if (time_after(this_rq->next_balance, rq->next_balance)) - this_rq->next_balance = rq->next_balance; - } - } -#endif -} - -static inline int on_null_domain(int cpu) -{ - return !rcu_dereference(cpu_rq(cpu)->sd); -} - -/* - * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. - * - * In case of CONFIG_NO_HZ, this is the place where we nominate a new - * idle load balancing owner or decide to stop the periodic load balancing, - * if the whole system is idle. - */ -static inline void trigger_load_balance(struct rq *rq, int cpu) -{ -#ifdef CONFIG_NO_HZ - /* - * If we were in the nohz mode recently and busy at the current - * scheduler tick, then check if we need to nominate new idle - * load balancer. - */ - if (rq->in_nohz_recently && !rq->idle_at_tick) { - rq->in_nohz_recently = 0; - - if (atomic_read(&nohz.load_balancer) == cpu) { - cpumask_clear_cpu(cpu, nohz.cpu_mask); - atomic_set(&nohz.load_balancer, -1); - } - - if (atomic_read(&nohz.load_balancer) == -1) { - int ilb = find_new_ilb(cpu); - - if (ilb < nr_cpu_ids) - resched_cpu(ilb); - } - } - - /* - * If this cpu is idle and doing idle load balancing for all the - * cpus with ticks stopped, is it time for that to stop? - */ - if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && - cpumask_weight(nohz.cpu_mask) == num_online_cpus()) { - resched_cpu(cpu); - return; - } - - /* - * If this cpu is idle and the idle load balancing is done by - * someone else, then no need raise the SCHED_SOFTIRQ - */ - if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && - cpumask_test_cpu(cpu, nohz.cpu_mask)) - return; -#endif - /* Don't need to rebalance while attached to NULL domain */ - if (time_after_eq(jiffies, rq->next_balance) && - likely(!on_null_domain(cpu))) - raise_softirq(SCHED_SOFTIRQ); -} - -#else /* CONFIG_SMP */ - -/* - * on UP we do not need to balance between CPUs: - */ -static inline void idle_balance(int cpu, struct rq *rq) -{ -} - #endif DEFINE_PER_CPU(struct kernel_stat, kstat); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 71778601c103..5116b81d7727 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1952,6 +1952,1762 @@ move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, return 0; } +/* + * pull_task - move a task from a remote runqueue to the local runqueue. + * Both runqueues must be locked. + */ +static void pull_task(struct rq *src_rq, struct task_struct *p, + struct rq *this_rq, int this_cpu) +{ + deactivate_task(src_rq, p, 0); + set_task_cpu(p, this_cpu); + activate_task(this_rq, p, 0); + check_preempt_curr(this_rq, p, 0); +} + +/* + * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? + */ +static +int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned) +{ + int tsk_cache_hot = 0; + /* + * We do not migrate tasks that are: + * 1) running (obviously), or + * 2) cannot be migrated to this CPU due to cpus_allowed, or + * 3) are cache-hot on their current CPU. + */ + if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) { + schedstat_inc(p, se.nr_failed_migrations_affine); + return 0; + } + *all_pinned = 0; + + if (task_running(rq, p)) { + schedstat_inc(p, se.nr_failed_migrations_running); + return 0; + } + + /* + * Aggressive migration if: + * 1) task is cache cold, or + * 2) too many balance attempts have failed. + */ + + tsk_cache_hot = task_hot(p, rq->clock, sd); + if (!tsk_cache_hot || + sd->nr_balance_failed > sd->cache_nice_tries) { +#ifdef CONFIG_SCHEDSTATS + if (tsk_cache_hot) { + schedstat_inc(sd, lb_hot_gained[idle]); + schedstat_inc(p, se.nr_forced_migrations); + } +#endif + return 1; + } + + if (tsk_cache_hot) { + schedstat_inc(p, se.nr_failed_migrations_hot); + return 0; + } + return 1; +} + +static unsigned long +balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, struct sched_domain *sd, + enum cpu_idle_type idle, int *all_pinned, + int *this_best_prio, struct rq_iterator *iterator) +{ + int loops = 0, pulled = 0, pinned = 0; + struct task_struct *p; + long rem_load_move = max_load_move; + + if (max_load_move == 0) + goto out; + + pinned = 1; + + /* + * Start the load-balancing iterator: + */ + p = iterator->start(iterator->arg); +next: + if (!p || loops++ > sysctl_sched_nr_migrate) + goto out; + + if ((p->se.load.weight >> 1) > rem_load_move || + !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { + p = iterator->next(iterator->arg); + goto next; + } + + pull_task(busiest, p, this_rq, this_cpu); + pulled++; + rem_load_move -= p->se.load.weight; + +#ifdef CONFIG_PREEMPT + /* + * NEWIDLE balancing is a source of latency, so preemptible kernels + * will stop after the first task is pulled to minimize the critical + * section. + */ + if (idle == CPU_NEWLY_IDLE) + goto out; +#endif + + /* + * We only want to steal up to the prescribed amount of weighted load. + */ + if (rem_load_move > 0) { + if (p->prio < *this_best_prio) + *this_best_prio = p->prio; + p = iterator->next(iterator->arg); + goto next; + } +out: + /* + * Right now, this is one of only two places pull_task() is called, + * so we can safely collect pull_task() stats here rather than + * inside pull_task(). + */ + schedstat_add(sd, lb_gained[idle], pulled); + + if (all_pinned) + *all_pinned = pinned; + + return max_load_move - rem_load_move; +} + +/* + * move_tasks tries to move up to max_load_move weighted load from busiest to + * this_rq, as part of a balancing operation within domain "sd". + * Returns 1 if successful and 0 otherwise. + * + * Called with both runqueues locked. + */ +static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned) +{ + const struct sched_class *class = sched_class_highest; + unsigned long total_load_moved = 0; + int this_best_prio = this_rq->curr->prio; + + do { + total_load_moved += + class->load_balance(this_rq, this_cpu, busiest, + max_load_move - total_load_moved, + sd, idle, all_pinned, &this_best_prio); + class = class->next; + +#ifdef CONFIG_PREEMPT + /* + * NEWIDLE balancing is a source of latency, so preemptible + * kernels will stop after the first task is pulled to minimize + * the critical section. + */ + if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) + break; +#endif + } while (class && max_load_move > total_load_moved); + + return total_load_moved > 0; +} + +static int +iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, + struct sched_domain *sd, enum cpu_idle_type idle, + struct rq_iterator *iterator) +{ + struct task_struct *p = iterator->start(iterator->arg); + int pinned = 0; + + while (p) { + if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { + pull_task(busiest, p, this_rq, this_cpu); + /* + * Right now, this is only the second place pull_task() + * is called, so we can safely collect pull_task() + * stats here rather than inside pull_task(). + */ + schedstat_inc(sd, lb_gained[idle]); + + return 1; + } + p = iterator->next(iterator->arg); + } + + return 0; +} + +/* + * move_one_task tries to move exactly one task from busiest to this_rq, as + * part of active balancing operations within "domain". + * Returns 1 if successful and 0 otherwise. + * + * Called with both runqueues locked. + */ +static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, + struct sched_domain *sd, enum cpu_idle_type idle) +{ + const struct sched_class *class; + + for_each_class(class) { + if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) + return 1; + } + + return 0; +} +/********** Helpers for find_busiest_group ************************/ +/* + * sd_lb_stats - Structure to store the statistics of a sched_domain + * during load balancing. + */ +struct sd_lb_stats { + struct sched_group *busiest; /* Busiest group in this sd */ + struct sched_group *this; /* Local group in this sd */ + unsigned long total_load; /* Total load of all groups in sd */ + unsigned long total_pwr; /* Total power of all groups in sd */ + unsigned long avg_load; /* Average load across all groups in sd */ + + /** Statistics of this group */ + unsigned long this_load; + unsigned long this_load_per_task; + unsigned long this_nr_running; + + /* Statistics of the busiest group */ + unsigned long max_load; + unsigned long busiest_load_per_task; + unsigned long busiest_nr_running; + + int group_imb; /* Is there imbalance in this sd */ +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) + int power_savings_balance; /* Is powersave balance needed for this sd */ + struct sched_group *group_min; /* Least loaded group in sd */ + struct sched_group *group_leader; /* Group which relieves group_min */ + unsigned long min_load_per_task; /* load_per_task in group_min */ + unsigned long leader_nr_running; /* Nr running of group_leader */ + unsigned long min_nr_running; /* Nr running of group_min */ +#endif +}; + +/* + * sg_lb_stats - stats of a sched_group required for load_balancing + */ +struct sg_lb_stats { + unsigned long avg_load; /*Avg load across the CPUs of the group */ + unsigned long group_load; /* Total load over the CPUs of the group */ + unsigned long sum_nr_running; /* Nr tasks running in the group */ + unsigned long sum_weighted_load; /* Weighted load of group's tasks */ + unsigned long group_capacity; + int group_imb; /* Is there an imbalance in the group ? */ +}; + +/** + * group_first_cpu - Returns the first cpu in the cpumask of a sched_group. + * @group: The group whose first cpu is to be returned. + */ +static inline unsigned int group_first_cpu(struct sched_group *group) +{ + return cpumask_first(sched_group_cpus(group)); +} + +/** + * get_sd_load_idx - Obtain the load index for a given sched domain. + * @sd: The sched_domain whose load_idx is to be obtained. + * @idle: The Idle status of the CPU for whose sd load_icx is obtained. + */ +static inline int get_sd_load_idx(struct sched_domain *sd, + enum cpu_idle_type idle) +{ + int load_idx; + + switch (idle) { + case CPU_NOT_IDLE: + load_idx = sd->busy_idx; + break; + + case CPU_NEWLY_IDLE: + load_idx = sd->newidle_idx; + break; + default: + load_idx = sd->idle_idx; + break; + } + + return load_idx; +} + + +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) +/** + * init_sd_power_savings_stats - Initialize power savings statistics for + * the given sched_domain, during load balancing. + * + * @sd: Sched domain whose power-savings statistics are to be initialized. + * @sds: Variable containing the statistics for sd. + * @idle: Idle status of the CPU at which we're performing load-balancing. + */ +static inline void init_sd_power_savings_stats(struct sched_domain *sd, + struct sd_lb_stats *sds, enum cpu_idle_type idle) +{ + /* + * Busy processors will not participate in power savings + * balance. + */ + if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) + sds->power_savings_balance = 0; + else { + sds->power_savings_balance = 1; + sds->min_nr_running = ULONG_MAX; + sds->leader_nr_running = 0; + } +} + +/** + * update_sd_power_savings_stats - Update the power saving stats for a + * sched_domain while performing load balancing. + * + * @group: sched_group belonging to the sched_domain under consideration. + * @sds: Variable containing the statistics of the sched_domain + * @local_group: Does group contain the CPU for which we're performing + * load balancing ? + * @sgs: Variable containing the statistics of the group. + */ +static inline void update_sd_power_savings_stats(struct sched_group *group, + struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) +{ + + if (!sds->power_savings_balance) + return; + + /* + * If the local group is idle or completely loaded + * no need to do power savings balance at this domain + */ + if (local_group && (sds->this_nr_running >= sgs->group_capacity || + !sds->this_nr_running)) + sds->power_savings_balance = 0; + + /* + * If a group is already running at full capacity or idle, + * don't include that group in power savings calculations + */ + if (!sds->power_savings_balance || + sgs->sum_nr_running >= sgs->group_capacity || + !sgs->sum_nr_running) + return; + + /* + * Calculate the group which has the least non-idle load. + * This is the group from where we need to pick up the load + * for saving power + */ + if ((sgs->sum_nr_running < sds->min_nr_running) || + (sgs->sum_nr_running == sds->min_nr_running && + group_first_cpu(group) > group_first_cpu(sds->group_min))) { + sds->group_min = group; + sds->min_nr_running = sgs->sum_nr_running; + sds->min_load_per_task = sgs->sum_weighted_load / + sgs->sum_nr_running; + } + + /* + * Calculate the group which is almost near its + * capacity but still has some space to pick up some load + * from other group and save more power + */ + if (sgs->sum_nr_running + 1 > sgs->group_capacity) + return; + + if (sgs->sum_nr_running > sds->leader_nr_running || + (sgs->sum_nr_running == sds->leader_nr_running && + group_first_cpu(group) < group_first_cpu(sds->group_leader))) { + sds->group_leader = group; + sds->leader_nr_running = sgs->sum_nr_running; + } +} + +/** + * check_power_save_busiest_group - see if there is potential for some power-savings balance + * @sds: Variable containing the statistics of the sched_domain + * under consideration. + * @this_cpu: Cpu at which we're currently performing load-balancing. + * @imbalance: Variable to store the imbalance. + * + * Description: + * Check if we have potential to perform some power-savings balance. + * If yes, set the busiest group to be the least loaded group in the + * sched_domain, so that it's CPUs can be put to idle. + * + * Returns 1 if there is potential to perform power-savings balance. + * Else returns 0. + */ +static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, + int this_cpu, unsigned long *imbalance) +{ + if (!sds->power_savings_balance) + return 0; + + if (sds->this != sds->group_leader || + sds->group_leader == sds->group_min) + return 0; + + *imbalance = sds->min_load_per_task; + sds->busiest = sds->group_min; + + return 1; + +} +#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ +static inline void init_sd_power_savings_stats(struct sched_domain *sd, + struct sd_lb_stats *sds, enum cpu_idle_type idle) +{ + return; +} + +static inline void update_sd_power_savings_stats(struct sched_group *group, + struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs) +{ + return; +} + +static inline int check_power_save_busiest_group(struct sd_lb_stats *sds, + int this_cpu, unsigned long *imbalance) +{ + return 0; +} +#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ + + +unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu) +{ + return SCHED_LOAD_SCALE; +} + +unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) +{ + return default_scale_freq_power(sd, cpu); +} + +unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) +{ + unsigned long weight = cpumask_weight(sched_domain_span(sd)); + unsigned long smt_gain = sd->smt_gain; + + smt_gain /= weight; + + return smt_gain; +} + +unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) +{ + return default_scale_smt_power(sd, cpu); +} + +unsigned long scale_rt_power(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + u64 total, available; + + sched_avg_update(rq); + + total = sched_avg_period() + (rq->clock - rq->age_stamp); + available = total - rq->rt_avg; + + if (unlikely((s64)total < SCHED_LOAD_SCALE)) + total = SCHED_LOAD_SCALE; + + total >>= SCHED_LOAD_SHIFT; + + return div_u64(available, total); +} + +static void update_cpu_power(struct sched_domain *sd, int cpu) +{ + unsigned long weight = cpumask_weight(sched_domain_span(sd)); + unsigned long power = SCHED_LOAD_SCALE; + struct sched_group *sdg = sd->groups; + + if (sched_feat(ARCH_POWER)) + power *= arch_scale_freq_power(sd, cpu); + else + power *= default_scale_freq_power(sd, cpu); + + power >>= SCHED_LOAD_SHIFT; + + if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) { + if (sched_feat(ARCH_POWER)) + power *= arch_scale_smt_power(sd, cpu); + else + power *= default_scale_smt_power(sd, cpu); + + power >>= SCHED_LOAD_SHIFT; + } + + power *= scale_rt_power(cpu); + power >>= SCHED_LOAD_SHIFT; + + if (!power) + power = 1; + + sdg->cpu_power = power; +} + +static void update_group_power(struct sched_domain *sd, int cpu) +{ + struct sched_domain *child = sd->child; + struct sched_group *group, *sdg = sd->groups; + unsigned long power; + + if (!child) { + update_cpu_power(sd, cpu); + return; + } + + power = 0; + + group = child->groups; + do { + power += group->cpu_power; + group = group->next; + } while (group != child->groups); + + sdg->cpu_power = power; +} + +/** + * update_sg_lb_stats - Update sched_group's statistics for load balancing. + * @sd: The sched_domain whose statistics are to be updated. + * @group: sched_group whose statistics are to be updated. + * @this_cpu: Cpu for which load balance is currently performed. + * @idle: Idle status of this_cpu + * @load_idx: Load index of sched_domain of this_cpu for load calc. + * @sd_idle: Idle status of the sched_domain containing group. + * @local_group: Does group contain this_cpu. + * @cpus: Set of cpus considered for load balancing. + * @balance: Should we balance. + * @sgs: variable to hold the statistics for this group. + */ +static inline void update_sg_lb_stats(struct sched_domain *sd, + struct sched_group *group, int this_cpu, + enum cpu_idle_type idle, int load_idx, int *sd_idle, + int local_group, const struct cpumask *cpus, + int *balance, struct sg_lb_stats *sgs) +{ + unsigned long load, max_cpu_load, min_cpu_load; + int i; + unsigned int balance_cpu = -1, first_idle_cpu = 0; + unsigned long sum_avg_load_per_task; + unsigned long avg_load_per_task; + + if (local_group) { + balance_cpu = group_first_cpu(group); + if (balance_cpu == this_cpu) + update_group_power(sd, this_cpu); + } + + /* Tally up the load of all CPUs in the group */ + sum_avg_load_per_task = avg_load_per_task = 0; + max_cpu_load = 0; + min_cpu_load = ~0UL; + + for_each_cpu_and(i, sched_group_cpus(group), cpus) { + struct rq *rq = cpu_rq(i); + + if (*sd_idle && rq->nr_running) + *sd_idle = 0; + + /* Bias balancing toward cpus of our domain */ + if (local_group) { + if (idle_cpu(i) && !first_idle_cpu) { + first_idle_cpu = 1; + balance_cpu = i; + } + + load = target_load(i, load_idx); + } else { + load = source_load(i, load_idx); + if (load > max_cpu_load) + max_cpu_load = load; + if (min_cpu_load > load) + min_cpu_load = load; + } + + sgs->group_load += load; + sgs->sum_nr_running += rq->nr_running; + sgs->sum_weighted_load += weighted_cpuload(i); + + sum_avg_load_per_task += cpu_avg_load_per_task(i); + } + + /* + * First idle cpu or the first cpu(busiest) in this sched group + * is eligible for doing load balancing at this and above + * domains. In the newly idle case, we will allow all the cpu's + * to do the newly idle load balance. + */ + if (idle != CPU_NEWLY_IDLE && local_group && + balance_cpu != this_cpu && balance) { + *balance = 0; + return; + } + + /* Adjust by relative CPU power of the group */ + sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; + + + /* + * Consider the group unbalanced when the imbalance is larger + * than the average weight of two tasks. + * + * APZ: with cgroup the avg task weight can vary wildly and + * might not be a suitable number - should we keep a + * normalized nr_running number somewhere that negates + * the hierarchy? + */ + avg_load_per_task = (sum_avg_load_per_task * SCHED_LOAD_SCALE) / + group->cpu_power; + + if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) + sgs->group_imb = 1; + + sgs->group_capacity = + DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE); +} + +/** + * update_sd_lb_stats - Update sched_group's statistics for load balancing. + * @sd: sched_domain whose statistics are to be updated. + * @this_cpu: Cpu for which load balance is currently performed. + * @idle: Idle status of this_cpu + * @sd_idle: Idle status of the sched_domain containing group. + * @cpus: Set of cpus considered for load balancing. + * @balance: Should we balance. + * @sds: variable to hold the statistics for this sched_domain. + */ +static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, + enum cpu_idle_type idle, int *sd_idle, + const struct cpumask *cpus, int *balance, + struct sd_lb_stats *sds) +{ + struct sched_domain *child = sd->child; + struct sched_group *group = sd->groups; + struct sg_lb_stats sgs; + int load_idx, prefer_sibling = 0; + + if (child && child->flags & SD_PREFER_SIBLING) + prefer_sibling = 1; + + init_sd_power_savings_stats(sd, sds, idle); + load_idx = get_sd_load_idx(sd, idle); + + do { + int local_group; + + local_group = cpumask_test_cpu(this_cpu, + sched_group_cpus(group)); + memset(&sgs, 0, sizeof(sgs)); + update_sg_lb_stats(sd, group, this_cpu, idle, load_idx, sd_idle, + local_group, cpus, balance, &sgs); + + if (local_group && balance && !(*balance)) + return; + + sds->total_load += sgs.group_load; + sds->total_pwr += group->cpu_power; + + /* + * In case the child domain prefers tasks go to siblings + * first, lower the group capacity to one so that we'll try + * and move all the excess tasks away. + */ + if (prefer_sibling) + sgs.group_capacity = min(sgs.group_capacity, 1UL); + + if (local_group) { + sds->this_load = sgs.avg_load; + sds->this = group; + sds->this_nr_running = sgs.sum_nr_running; + sds->this_load_per_task = sgs.sum_weighted_load; + } else if (sgs.avg_load > sds->max_load && + (sgs.sum_nr_running > sgs.group_capacity || + sgs.group_imb)) { + sds->max_load = sgs.avg_load; + sds->busiest = group; + sds->busiest_nr_running = sgs.sum_nr_running; + sds->busiest_load_per_task = sgs.sum_weighted_load; + sds->group_imb = sgs.group_imb; + } + + update_sd_power_savings_stats(group, sds, local_group, &sgs); + group = group->next; + } while (group != sd->groups); +} + +/** + * fix_small_imbalance - Calculate the minor imbalance that exists + * amongst the groups of a sched_domain, during + * load balancing. + * @sds: Statistics of the sched_domain whose imbalance is to be calculated. + * @this_cpu: The cpu at whose sched_domain we're performing load-balance. + * @imbalance: Variable to store the imbalance. + */ +static inline void fix_small_imbalance(struct sd_lb_stats *sds, + int this_cpu, unsigned long *imbalance) +{ + unsigned long tmp, pwr_now = 0, pwr_move = 0; + unsigned int imbn = 2; + + if (sds->this_nr_running) { + sds->this_load_per_task /= sds->this_nr_running; + if (sds->busiest_load_per_task > + sds->this_load_per_task) + imbn = 1; + } else + sds->this_load_per_task = + cpu_avg_load_per_task(this_cpu); + + if (sds->max_load - sds->this_load + sds->busiest_load_per_task >= + sds->busiest_load_per_task * imbn) { + *imbalance = sds->busiest_load_per_task; + return; + } + + /* + * OK, we don't have enough imbalance to justify moving tasks, + * however we may be able to increase total CPU power used by + * moving them. + */ + + pwr_now += sds->busiest->cpu_power * + min(sds->busiest_load_per_task, sds->max_load); + pwr_now += sds->this->cpu_power * + min(sds->this_load_per_task, sds->this_load); + pwr_now /= SCHED_LOAD_SCALE; + + /* Amount of load we'd subtract */ + tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / + sds->busiest->cpu_power; + if (sds->max_load > tmp) + pwr_move += sds->busiest->cpu_power * + min(sds->busiest_load_per_task, sds->max_load - tmp); + + /* Amount of load we'd add */ + if (sds->max_load * sds->busiest->cpu_power < + sds->busiest_load_per_task * SCHED_LOAD_SCALE) + tmp = (sds->max_load * sds->busiest->cpu_power) / + sds->this->cpu_power; + else + tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) / + sds->this->cpu_power; + pwr_move += sds->this->cpu_power * + min(sds->this_load_per_task, sds->this_load + tmp); + pwr_move /= SCHED_LOAD_SCALE; + + /* Move if we gain throughput */ + if (pwr_move > pwr_now) + *imbalance = sds->busiest_load_per_task; +} + +/** + * calculate_imbalance - Calculate the amount of imbalance present within the + * groups of a given sched_domain during load balance. + * @sds: statistics of the sched_domain whose imbalance is to be calculated. + * @this_cpu: Cpu for which currently load balance is being performed. + * @imbalance: The variable to store the imbalance. + */ +static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, + unsigned long *imbalance) +{ + unsigned long max_pull; + /* + * In the presence of smp nice balancing, certain scenarios can have + * max load less than avg load(as we skip the groups at or below + * its cpu_power, while calculating max_load..) + */ + if (sds->max_load < sds->avg_load) { + *imbalance = 0; + return fix_small_imbalance(sds, this_cpu, imbalance); + } + + /* Don't want to pull so many tasks that a group would go idle */ + max_pull = min(sds->max_load - sds->avg_load, + sds->max_load - sds->busiest_load_per_task); + + /* How much load to actually move to equalise the imbalance */ + *imbalance = min(max_pull * sds->busiest->cpu_power, + (sds->avg_load - sds->this_load) * sds->this->cpu_power) + / SCHED_LOAD_SCALE; + + /* + * if *imbalance is less than the average load per runnable task + * there is no gaurantee that any tasks will be moved so we'll have + * a think about bumping its value to force at least one task to be + * moved + */ + if (*imbalance < sds->busiest_load_per_task) + return fix_small_imbalance(sds, this_cpu, imbalance); + +} +/******* find_busiest_group() helpers end here *********************/ + +/** + * find_busiest_group - Returns the busiest group within the sched_domain + * if there is an imbalance. If there isn't an imbalance, and + * the user has opted for power-savings, it returns a group whose + * CPUs can be put to idle by rebalancing those tasks elsewhere, if + * such a group exists. + * + * Also calculates the amount of weighted load which should be moved + * to restore balance. + * + * @sd: The sched_domain whose busiest group is to be returned. + * @this_cpu: The cpu for which load balancing is currently being performed. + * @imbalance: Variable which stores amount of weighted load which should + * be moved to restore balance/put a group to idle. + * @idle: The idle status of this_cpu. + * @sd_idle: The idleness of sd + * @cpus: The set of CPUs under consideration for load-balancing. + * @balance: Pointer to a variable indicating if this_cpu + * is the appropriate cpu to perform load balancing at this_level. + * + * Returns: - the busiest group if imbalance exists. + * - If no imbalance and user has opted for power-savings balance, + * return the least loaded group whose CPUs can be + * put to idle by rebalancing its tasks onto our group. + */ +static struct sched_group * +find_busiest_group(struct sched_domain *sd, int this_cpu, + unsigned long *imbalance, enum cpu_idle_type idle, + int *sd_idle, const struct cpumask *cpus, int *balance) +{ + struct sd_lb_stats sds; + + memset(&sds, 0, sizeof(sds)); + + /* + * Compute the various statistics relavent for load balancing at + * this level. + */ + update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus, + balance, &sds); + + /* Cases where imbalance does not exist from POV of this_cpu */ + /* 1) this_cpu is not the appropriate cpu to perform load balancing + * at this level. + * 2) There is no busy sibling group to pull from. + * 3) This group is the busiest group. + * 4) This group is more busy than the avg busieness at this + * sched_domain. + * 5) The imbalance is within the specified limit. + * 6) Any rebalance would lead to ping-pong + */ + if (balance && !(*balance)) + goto ret; + + if (!sds.busiest || sds.busiest_nr_running == 0) + goto out_balanced; + + if (sds.this_load >= sds.max_load) + goto out_balanced; + + sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr; + + if (sds.this_load >= sds.avg_load) + goto out_balanced; + + if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) + goto out_balanced; + + sds.busiest_load_per_task /= sds.busiest_nr_running; + if (sds.group_imb) + sds.busiest_load_per_task = + min(sds.busiest_load_per_task, sds.avg_load); + + /* + * We're trying to get all the cpus to the average_load, so we don't + * want to push ourselves above the average load, nor do we wish to + * reduce the max loaded cpu below the average load, as either of these + * actions would just result in more rebalancing later, and ping-pong + * tasks around. Thus we look for the minimum possible imbalance. + * Negative imbalances (*we* are more loaded than anyone else) will + * be counted as no imbalance for these purposes -- we can't fix that + * by pulling tasks to us. Be careful of negative numbers as they'll + * appear as very large values with unsigned longs. + */ + if (sds.max_load <= sds.busiest_load_per_task) + goto out_balanced; + + /* Looks like there is an imbalance. Compute it */ + calculate_imbalance(&sds, this_cpu, imbalance); + return sds.busiest; + +out_balanced: + /* + * There is no obvious imbalance. But check if we can do some balancing + * to save power. + */ + if (check_power_save_busiest_group(&sds, this_cpu, imbalance)) + return sds.busiest; +ret: + *imbalance = 0; + return NULL; +} + +/* + * find_busiest_queue - find the busiest runqueue among the cpus in group. + */ +static struct rq * +find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, + unsigned long imbalance, const struct cpumask *cpus) +{ + struct rq *busiest = NULL, *rq; + unsigned long max_load = 0; + int i; + + for_each_cpu(i, sched_group_cpus(group)) { + unsigned long power = power_of(i); + unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); + unsigned long wl; + + if (!cpumask_test_cpu(i, cpus)) + continue; + + rq = cpu_rq(i); + wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; + wl /= power; + + if (capacity && rq->nr_running == 1 && wl > imbalance) + continue; + + if (wl > max_load) { + max_load = wl; + busiest = rq; + } + } + + return busiest; +} + +/* + * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but + * so long as it is large enough. + */ +#define MAX_PINNED_INTERVAL 512 + +/* Working cpumask for load_balance and load_balance_newidle. */ +static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); + +/* + * Check this_cpu to ensure it is balanced within domain. Attempt to move + * tasks if there is an imbalance. + */ +static int load_balance(int this_cpu, struct rq *this_rq, + struct sched_domain *sd, enum cpu_idle_type idle, + int *balance) +{ + int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; + struct sched_group *group; + unsigned long imbalance; + struct rq *busiest; + unsigned long flags; + struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); + + cpumask_copy(cpus, cpu_active_mask); + + /* + * When power savings policy is enabled for the parent domain, idle + * sibling can pick up load irrespective of busy siblings. In this case, + * let the state of idle sibling percolate up as CPU_IDLE, instead of + * portraying it as CPU_NOT_IDLE. + */ + if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + sd_idle = 1; + + schedstat_inc(sd, lb_count[idle]); + +redo: + update_shares(sd); + group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, + cpus, balance); + + if (*balance == 0) + goto out_balanced; + + if (!group) { + schedstat_inc(sd, lb_nobusyg[idle]); + goto out_balanced; + } + + busiest = find_busiest_queue(group, idle, imbalance, cpus); + if (!busiest) { + schedstat_inc(sd, lb_nobusyq[idle]); + goto out_balanced; + } + + BUG_ON(busiest == this_rq); + + schedstat_add(sd, lb_imbalance[idle], imbalance); + + ld_moved = 0; + if (busiest->nr_running > 1) { + /* + * Attempt to move tasks. If find_busiest_group has found + * an imbalance but busiest->nr_running <= 1, the group is + * still unbalanced. ld_moved simply stays zero, so it is + * correctly treated as an imbalance. + */ + local_irq_save(flags); + double_rq_lock(this_rq, busiest); + ld_moved = move_tasks(this_rq, this_cpu, busiest, + imbalance, sd, idle, &all_pinned); + double_rq_unlock(this_rq, busiest); + local_irq_restore(flags); + + /* + * some other cpu did the load balance for us. + */ + if (ld_moved && this_cpu != smp_processor_id()) + resched_cpu(this_cpu); + + /* All tasks on this runqueue were pinned by CPU affinity */ + if (unlikely(all_pinned)) { + cpumask_clear_cpu(cpu_of(busiest), cpus); + if (!cpumask_empty(cpus)) + goto redo; + goto out_balanced; + } + } + + if (!ld_moved) { + schedstat_inc(sd, lb_failed[idle]); + sd->nr_balance_failed++; + + if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { + + raw_spin_lock_irqsave(&busiest->lock, flags); + + /* don't kick the migration_thread, if the curr + * task on busiest cpu can't be moved to this_cpu + */ + if (!cpumask_test_cpu(this_cpu, + &busiest->curr->cpus_allowed)) { + raw_spin_unlock_irqrestore(&busiest->lock, + flags); + all_pinned = 1; + goto out_one_pinned; + } + + if (!busiest->active_balance) { + busiest->active_balance = 1; + busiest->push_cpu = this_cpu; + active_balance = 1; + } + raw_spin_unlock_irqrestore(&busiest->lock, flags); + if (active_balance) + wake_up_process(busiest->migration_thread); + + /* + * We've kicked active balancing, reset the failure + * counter. + */ + sd->nr_balance_failed = sd->cache_nice_tries+1; + } + } else + sd->nr_balance_failed = 0; + + if (likely(!active_balance)) { + /* We were unbalanced, so reset the balancing interval */ + sd->balance_interval = sd->min_interval; + } else { + /* + * If we've begun active balancing, start to back off. This + * case may not be covered by the all_pinned logic if there + * is only 1 task on the busy runqueue (because we don't call + * move_tasks). + */ + if (sd->balance_interval < sd->max_interval) + sd->balance_interval *= 2; + } + + if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + ld_moved = -1; + + goto out; + +out_balanced: + schedstat_inc(sd, lb_balanced[idle]); + + sd->nr_balance_failed = 0; + +out_one_pinned: + /* tune up the balancing interval */ + if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || + (sd->balance_interval < sd->max_interval)) + sd->balance_interval *= 2; + + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + ld_moved = -1; + else + ld_moved = 0; +out: + if (ld_moved) + update_shares(sd); + return ld_moved; +} + +/* + * Check this_cpu to ensure it is balanced within domain. Attempt to move + * tasks if there is an imbalance. + * + * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). + * this_rq is locked. + */ +static int +load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) +{ + struct sched_group *group; + struct rq *busiest = NULL; + unsigned long imbalance; + int ld_moved = 0; + int sd_idle = 0; + int all_pinned = 0; + struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); + + cpumask_copy(cpus, cpu_active_mask); + + /* + * When power savings policy is enabled for the parent domain, idle + * sibling can pick up load irrespective of busy siblings. In this case, + * let the state of idle sibling percolate up as IDLE, instead of + * portraying it as CPU_NOT_IDLE. + */ + if (sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + sd_idle = 1; + + schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); +redo: + update_shares_locked(this_rq, sd); + group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, + &sd_idle, cpus, NULL); + if (!group) { + schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); + goto out_balanced; + } + + busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus); + if (!busiest) { + schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); + goto out_balanced; + } + + BUG_ON(busiest == this_rq); + + schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); + + ld_moved = 0; + if (busiest->nr_running > 1) { + /* Attempt to move tasks */ + double_lock_balance(this_rq, busiest); + /* this_rq->clock is already updated */ + update_rq_clock(busiest); + ld_moved = move_tasks(this_rq, this_cpu, busiest, + imbalance, sd, CPU_NEWLY_IDLE, + &all_pinned); + double_unlock_balance(this_rq, busiest); + + if (unlikely(all_pinned)) { + cpumask_clear_cpu(cpu_of(busiest), cpus); + if (!cpumask_empty(cpus)) + goto redo; + } + } + + if (!ld_moved) { + int active_balance = 0; + + schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return -1; + + if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) + return -1; + + if (sd->nr_balance_failed++ < 2) + return -1; + + /* + * The only task running in a non-idle cpu can be moved to this + * cpu in an attempt to completely freeup the other CPU + * package. The same method used to move task in load_balance() + * have been extended for load_balance_newidle() to speedup + * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2) + * + * The package power saving logic comes from + * find_busiest_group(). If there are no imbalance, then + * f_b_g() will return NULL. However when sched_mc={1,2} then + * f_b_g() will select a group from which a running task may be + * pulled to this cpu in order to make the other package idle. + * If there is no opportunity to make a package idle and if + * there are no imbalance, then f_b_g() will return NULL and no + * action will be taken in load_balance_newidle(). + * + * Under normal task pull operation due to imbalance, there + * will be more than one task in the source run queue and + * move_tasks() will succeed. ld_moved will be true and this + * active balance code will not be triggered. + */ + + /* Lock busiest in correct order while this_rq is held */ + double_lock_balance(this_rq, busiest); + + /* + * don't kick the migration_thread, if the curr + * task on busiest cpu can't be moved to this_cpu + */ + if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) { + double_unlock_balance(this_rq, busiest); + all_pinned = 1; + return ld_moved; + } + + if (!busiest->active_balance) { + busiest->active_balance = 1; + busiest->push_cpu = this_cpu; + active_balance = 1; + } + + double_unlock_balance(this_rq, busiest); + /* + * Should not call ttwu while holding a rq->lock + */ + raw_spin_unlock(&this_rq->lock); + if (active_balance) + wake_up_process(busiest->migration_thread); + raw_spin_lock(&this_rq->lock); + + } else + sd->nr_balance_failed = 0; + + update_shares_locked(this_rq, sd); + return ld_moved; + +out_balanced: + schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return -1; + sd->nr_balance_failed = 0; + + return 0; +} + +/* + * idle_balance is called by schedule() if this_cpu is about to become + * idle. Attempts to pull tasks from other CPUs. + */ +static void idle_balance(int this_cpu, struct rq *this_rq) +{ + struct sched_domain *sd; + int pulled_task = 0; + unsigned long next_balance = jiffies + HZ; + + this_rq->idle_stamp = this_rq->clock; + + if (this_rq->avg_idle < sysctl_sched_migration_cost) + return; + + for_each_domain(this_cpu, sd) { + unsigned long interval; + + if (!(sd->flags & SD_LOAD_BALANCE)) + continue; + + if (sd->flags & SD_BALANCE_NEWIDLE) + /* If we've pulled tasks over stop searching: */ + pulled_task = load_balance_newidle(this_cpu, this_rq, + sd); + + interval = msecs_to_jiffies(sd->balance_interval); + if (time_after(next_balance, sd->last_balance + interval)) + next_balance = sd->last_balance + interval; + if (pulled_task) { + this_rq->idle_stamp = 0; + break; + } + } + if (pulled_task || time_after(jiffies, this_rq->next_balance)) { + /* + * We are going idle. next_balance may be set based on + * a busy processor. So reset next_balance. + */ + this_rq->next_balance = next_balance; + } +} + +/* + * active_load_balance is run by migration threads. It pushes running tasks + * off the busiest CPU onto idle CPUs. It requires at least 1 task to be + * running on each physical CPU where possible, and avoids physical / + * logical imbalances. + * + * Called with busiest_rq locked. + */ +static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) +{ + int target_cpu = busiest_rq->push_cpu; + struct sched_domain *sd; + struct rq *target_rq; + + /* Is there any task to move? */ + if (busiest_rq->nr_running <= 1) + return; + + target_rq = cpu_rq(target_cpu); + + /* + * This condition is "impossible", if it occurs + * we need to fix it. Originally reported by + * Bjorn Helgaas on a 128-cpu setup. + */ + BUG_ON(busiest_rq == target_rq); + + /* move a task from busiest_rq to target_rq */ + double_lock_balance(busiest_rq, target_rq); + update_rq_clock(busiest_rq); + update_rq_clock(target_rq); + + /* Search for an sd spanning us and the target CPU. */ + for_each_domain(target_cpu, sd) { + if ((sd->flags & SD_LOAD_BALANCE) && + cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) + break; + } + + if (likely(sd)) { + schedstat_inc(sd, alb_count); + + if (move_one_task(target_rq, target_cpu, busiest_rq, + sd, CPU_IDLE)) + schedstat_inc(sd, alb_pushed); + else + schedstat_inc(sd, alb_failed); + } + double_unlock_balance(busiest_rq, target_rq); +} + +#ifdef CONFIG_NO_HZ +static struct { + atomic_t load_balancer; + cpumask_var_t cpu_mask; + cpumask_var_t ilb_grp_nohz_mask; +} nohz ____cacheline_aligned = { + .load_balancer = ATOMIC_INIT(-1), +}; + +int get_nohz_load_balancer(void) +{ + return atomic_read(&nohz.load_balancer); +} + +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) +/** + * lowest_flag_domain - Return lowest sched_domain containing flag. + * @cpu: The cpu whose lowest level of sched domain is to + * be returned. + * @flag: The flag to check for the lowest sched_domain + * for the given cpu. + * + * Returns the lowest sched_domain of a cpu which contains the given flag. + */ +static inline struct sched_domain *lowest_flag_domain(int cpu, int flag) +{ + struct sched_domain *sd; + + for_each_domain(cpu, sd) + if (sd && (sd->flags & flag)) + break; + + return sd; +} + +/** + * for_each_flag_domain - Iterates over sched_domains containing the flag. + * @cpu: The cpu whose domains we're iterating over. + * @sd: variable holding the value of the power_savings_sd + * for cpu. + * @flag: The flag to filter the sched_domains to be iterated. + * + * Iterates over all the scheduler domains for a given cpu that has the 'flag' + * set, starting from the lowest sched_domain to the highest. + */ +#define for_each_flag_domain(cpu, sd, flag) \ + for (sd = lowest_flag_domain(cpu, flag); \ + (sd && (sd->flags & flag)); sd = sd->parent) + +/** + * is_semi_idle_group - Checks if the given sched_group is semi-idle. + * @ilb_group: group to be checked for semi-idleness + * + * Returns: 1 if the group is semi-idle. 0 otherwise. + * + * We define a sched_group to be semi idle if it has atleast one idle-CPU + * and atleast one non-idle CPU. This helper function checks if the given + * sched_group is semi-idle or not. + */ +static inline int is_semi_idle_group(struct sched_group *ilb_group) +{ + cpumask_and(nohz.ilb_grp_nohz_mask, nohz.cpu_mask, + sched_group_cpus(ilb_group)); + + /* + * A sched_group is semi-idle when it has atleast one busy cpu + * and atleast one idle cpu. + */ + if (cpumask_empty(nohz.ilb_grp_nohz_mask)) + return 0; + + if (cpumask_equal(nohz.ilb_grp_nohz_mask, sched_group_cpus(ilb_group))) + return 0; + + return 1; +} +/** + * find_new_ilb - Finds the optimum idle load balancer for nomination. + * @cpu: The cpu which is nominating a new idle_load_balancer. + * + * Returns: Returns the id of the idle load balancer if it exists, + * Else, returns >= nr_cpu_ids. + * + * This algorithm picks the idle load balancer such that it belongs to a + * semi-idle powersavings sched_domain. The idea is to try and avoid + * completely idle packages/cores just for the purpose of idle load balancing + * when there are other idle cpu's which are better suited for that job. + */ +static int find_new_ilb(int cpu) +{ + struct sched_domain *sd; + struct sched_group *ilb_group; + + /* + * Have idle load balancer selection from semi-idle packages only + * when power-aware load balancing is enabled + */ + if (!(sched_smt_power_savings || sched_mc_power_savings)) + goto out_done; + + /* + * Optimize for the case when we have no idle CPUs or only one + * idle CPU. Don't walk the sched_domain hierarchy in such cases + */ + if (cpumask_weight(nohz.cpu_mask) < 2) + goto out_done; + + for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) { + ilb_group = sd->groups; + + do { + if (is_semi_idle_group(ilb_group)) + return cpumask_first(nohz.ilb_grp_nohz_mask); + + ilb_group = ilb_group->next; + + } while (ilb_group != sd->groups); + } + +out_done: + return cpumask_first(nohz.cpu_mask); +} +#else /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */ +static inline int find_new_ilb(int call_cpu) +{ + return cpumask_first(nohz.cpu_mask); +} +#endif + +/* + * This routine will try to nominate the ilb (idle load balancing) + * owner among the cpus whose ticks are stopped. ilb owner will do the idle + * load balancing on behalf of all those cpus. If all the cpus in the system + * go into this tickless mode, then there will be no ilb owner (as there is + * no need for one) and all the cpus will sleep till the next wakeup event + * arrives... + * + * For the ilb owner, tick is not stopped. And this tick will be used + * for idle load balancing. ilb owner will still be part of + * nohz.cpu_mask.. + * + * While stopping the tick, this cpu will become the ilb owner if there + * is no other owner. And will be the owner till that cpu becomes busy + * or if all cpus in the system stop their ticks at which point + * there is no need for ilb owner. + * + * When the ilb owner becomes busy, it nominates another owner, during the + * next busy scheduler_tick() + */ +int select_nohz_load_balancer(int stop_tick) +{ + int cpu = smp_processor_id(); + + if (stop_tick) { + cpu_rq(cpu)->in_nohz_recently = 1; + + if (!cpu_active(cpu)) { + if (atomic_read(&nohz.load_balancer) != cpu) + return 0; + + /* + * If we are going offline and still the leader, + * give up! + */ + if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) + BUG(); + + return 0; + } + + cpumask_set_cpu(cpu, nohz.cpu_mask); + + /* time for ilb owner also to sleep */ + if (cpumask_weight(nohz.cpu_mask) == num_active_cpus()) { + if (atomic_read(&nohz.load_balancer) == cpu) + atomic_set(&nohz.load_balancer, -1); + return 0; + } + + if (atomic_read(&nohz.load_balancer) == -1) { + /* make me the ilb owner */ + if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) + return 1; + } else if (atomic_read(&nohz.load_balancer) == cpu) { + int new_ilb; + + if (!(sched_smt_power_savings || + sched_mc_power_savings)) + return 1; + /* + * Check to see if there is a more power-efficient + * ilb. + */ + new_ilb = find_new_ilb(cpu); + if (new_ilb < nr_cpu_ids && new_ilb != cpu) { + atomic_set(&nohz.load_balancer, -1); + resched_cpu(new_ilb); + return 0; + } + return 1; + } + } else { + if (!cpumask_test_cpu(cpu, nohz.cpu_mask)) + return 0; + + cpumask_clear_cpu(cpu, nohz.cpu_mask); + + if (atomic_read(&nohz.load_balancer) == cpu) + if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) + BUG(); + } + return 0; +} +#endif + +static DEFINE_SPINLOCK(balancing); + +/* + * It checks each scheduling domain to see if it is due to be balanced, + * and initiates a balancing operation if so. + * + * Balancing parameters are set up in arch_init_sched_domains. + */ +static void rebalance_domains(int cpu, enum cpu_idle_type idle) +{ + int balance = 1; + struct rq *rq = cpu_rq(cpu); + unsigned long interval; + struct sched_domain *sd; + /* Earliest time when we have to do rebalance again */ + unsigned long next_balance = jiffies + 60*HZ; + int update_next_balance = 0; + int need_serialize; + + for_each_domain(cpu, sd) { + if (!(sd->flags & SD_LOAD_BALANCE)) + continue; + + interval = sd->balance_interval; + if (idle != CPU_IDLE) + interval *= sd->busy_factor; + + /* scale ms to jiffies */ + interval = msecs_to_jiffies(interval); + if (unlikely(!interval)) + interval = 1; + if (interval > HZ*NR_CPUS/10) + interval = HZ*NR_CPUS/10; + + need_serialize = sd->flags & SD_SERIALIZE; + + if (need_serialize) { + if (!spin_trylock(&balancing)) + goto out; + } + + if (time_after_eq(jiffies, sd->last_balance + interval)) { + if (load_balance(cpu, rq, sd, idle, &balance)) { + /* + * We've pulled tasks over so either we're no + * longer idle, or one of our SMT siblings is + * not idle. + */ + idle = CPU_NOT_IDLE; + } + sd->last_balance = jiffies; + } + if (need_serialize) + spin_unlock(&balancing); +out: + if (time_after(next_balance, sd->last_balance + interval)) { + next_balance = sd->last_balance + interval; + update_next_balance = 1; + } + + /* + * Stop the load balance at this level. There is another + * CPU in our sched group which is doing load balancing more + * actively. + */ + if (!balance) + break; + } + + /* + * next_balance will be updated only when there is a need. + * When the cpu is attached to null domain for ex, it will not be + * updated. + */ + if (likely(update_next_balance)) + rq->next_balance = next_balance; +} + +/* + * run_rebalance_domains is triggered when needed from the scheduler tick. + * In CONFIG_NO_HZ case, the idle load balance owner will do the + * rebalancing for all the cpus for whom scheduler ticks are stopped. + */ +static void run_rebalance_domains(struct softirq_action *h) +{ + int this_cpu = smp_processor_id(); + struct rq *this_rq = cpu_rq(this_cpu); + enum cpu_idle_type idle = this_rq->idle_at_tick ? + CPU_IDLE : CPU_NOT_IDLE; + + rebalance_domains(this_cpu, idle); + +#ifdef CONFIG_NO_HZ + /* + * If this cpu is the owner for idle load balancing, then do the + * balancing on behalf of the other idle cpus whose ticks are + * stopped. + */ + if (this_rq->idle_at_tick && + atomic_read(&nohz.load_balancer) == this_cpu) { + struct rq *rq; + int balance_cpu; + + for_each_cpu(balance_cpu, nohz.cpu_mask) { + if (balance_cpu == this_cpu) + continue; + + /* + * If this cpu gets work to do, stop the load balancing + * work being done for other cpus. Next load + * balancing owner will pick it up. + */ + if (need_resched()) + break; + + rebalance_domains(balance_cpu, CPU_IDLE); + + rq = cpu_rq(balance_cpu); + if (time_after(this_rq->next_balance, rq->next_balance)) + this_rq->next_balance = rq->next_balance; + } + } +#endif +} + +static inline int on_null_domain(int cpu) +{ + return !rcu_dereference(cpu_rq(cpu)->sd); +} + +/* + * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. + * + * In case of CONFIG_NO_HZ, this is the place where we nominate a new + * idle load balancing owner or decide to stop the periodic load balancing, + * if the whole system is idle. + */ +static inline void trigger_load_balance(struct rq *rq, int cpu) +{ +#ifdef CONFIG_NO_HZ + /* + * If we were in the nohz mode recently and busy at the current + * scheduler tick, then check if we need to nominate new idle + * load balancer. + */ + if (rq->in_nohz_recently && !rq->idle_at_tick) { + rq->in_nohz_recently = 0; + + if (atomic_read(&nohz.load_balancer) == cpu) { + cpumask_clear_cpu(cpu, nohz.cpu_mask); + atomic_set(&nohz.load_balancer, -1); + } + + if (atomic_read(&nohz.load_balancer) == -1) { + int ilb = find_new_ilb(cpu); + + if (ilb < nr_cpu_ids) + resched_cpu(ilb); + } + } + + /* + * If this cpu is idle and doing idle load balancing for all the + * cpus with ticks stopped, is it time for that to stop? + */ + if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && + cpumask_weight(nohz.cpu_mask) == num_online_cpus()) { + resched_cpu(cpu); + return; + } + + /* + * If this cpu is idle and the idle load balancing is done by + * someone else, then no need raise the SCHED_SOFTIRQ + */ + if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && + cpumask_test_cpu(cpu, nohz.cpu_mask)) + return; +#endif + /* Don't need to rebalance while attached to NULL domain */ + if (time_after_eq(jiffies, rq->next_balance) && + likely(!on_null_domain(cpu))) + raise_softirq(SCHED_SOFTIRQ); +} + static void rq_online_fair(struct rq *rq) { update_sysctl(); @@ -1962,6 +3718,15 @@ static void rq_offline_fair(struct rq *rq) update_sysctl(); } +#else /* CONFIG_SMP */ + +/* + * on UP we do not need to balance between CPUs: + */ +static inline void idle_balance(int cpu, struct rq *rq) +{ +} + #endif /* CONFIG_SMP */ /* -- cgit v1.2.3 From 3d45fd804a95055ecab5b3eed81f5ab2dbb047a2 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 17:12:46 +0100 Subject: sched: Remove the sched_class load_balance methods Take out the sched_class methods for load-balancing. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/sched.h | 8 ------ kernel/sched.c | 26 ------------------- kernel/sched_fair.c | 66 +++++++++++++++++++++++++++---------------------- kernel/sched_idletask.c | 21 ---------------- kernel/sched_rt.c | 20 --------------- 5 files changed, 37 insertions(+), 104 deletions(-) (limited to 'kernel') diff --git a/include/linux/sched.h b/include/linux/sched.h index f2f842db03ce..50d685cde70e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1087,14 +1087,6 @@ struct sched_class { #ifdef CONFIG_SMP int (*select_task_rq)(struct task_struct *p, int sd_flag, int flags); - unsigned long (*load_balance) (struct rq *this_rq, int this_cpu, - struct rq *busiest, unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio); - - int (*move_one_task) (struct rq *this_rq, int this_cpu, - struct rq *busiest, struct sched_domain *sd, - enum cpu_idle_type idle); void (*pre_schedule) (struct rq *this_rq, struct task_struct *task); void (*post_schedule) (struct rq *this_rq); void (*task_waking) (struct rq *this_rq, struct task_struct *task); diff --git a/kernel/sched.c b/kernel/sched.c index 13a2acf18b2d..c0be07932a8d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1390,32 +1390,6 @@ static const u32 prio_to_wmult[40] = { /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, }; -static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); - -/* - * runqueue iterator, to support SMP load-balancing between different - * scheduling classes, without having to expose their internal data - * structures to the load-balancing proper: - */ -struct rq_iterator { - void *arg; - struct task_struct *(*start)(void *); - struct task_struct *(*next)(void *); -}; - -#ifdef CONFIG_SMP -static unsigned long -balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, struct sched_domain *sd, - enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct rq_iterator *iterator); - -static int -iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle, - struct rq_iterator *iterator); -#endif - /* Time spent by the tasks of the cpu accounting group executing in ... */ enum cpuacct_stat_index { CPUACCT_STAT_USER, /* ... user mode */ diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 5116b81d7727..faf9a2f099ab 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1851,6 +1851,24 @@ static struct task_struct *load_balance_next_fair(void *arg) return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator); } +/* + * runqueue iterator, to support SMP load-balancing between different + * scheduling classes, without having to expose their internal data + * structures to the load-balancing proper: + */ +struct rq_iterator { + void *arg; + struct task_struct *(*start)(void *); + struct task_struct *(*next)(void *); +}; + +static unsigned long +balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, struct sched_domain *sd, + enum cpu_idle_type idle, int *all_pinned, + int *this_best_prio, struct rq_iterator *iterator); + + static unsigned long __load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, @@ -1929,8 +1947,20 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, #endif static int -move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) +iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, + struct sched_domain *sd, enum cpu_idle_type idle, + struct rq_iterator *iterator); + +/* + * move_one_task tries to move exactly one task from busiest to this_rq, as + * part of active balancing operations within "domain". + * Returns 1 if successful and 0 otherwise. + * + * Called with both runqueues locked. + */ +static int +move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, + struct sched_domain *sd, enum cpu_idle_type idle) { struct cfs_rq *busy_cfs_rq; struct rq_iterator cfs_rq_iterator; @@ -2094,16 +2124,15 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, struct sched_domain *sd, enum cpu_idle_type idle, int *all_pinned) { - const struct sched_class *class = sched_class_highest; - unsigned long total_load_moved = 0; + unsigned long total_load_moved = 0, load_moved; int this_best_prio = this_rq->curr->prio; do { - total_load_moved += - class->load_balance(this_rq, this_cpu, busiest, + load_moved = load_balance_fair(this_rq, this_cpu, busiest, max_load_move - total_load_moved, sd, idle, all_pinned, &this_best_prio); - class = class->next; + + total_load_moved += load_moved; #ifdef CONFIG_PREEMPT /* @@ -2114,7 +2143,7 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) break; #endif - } while (class && max_load_move > total_load_moved); + } while (load_moved && max_load_move > total_load_moved); return total_load_moved > 0; } @@ -2145,25 +2174,6 @@ iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, return 0; } -/* - * move_one_task tries to move exactly one task from busiest to this_rq, as - * part of active balancing operations within "domain". - * Returns 1 if successful and 0 otherwise. - * - * Called with both runqueues locked. - */ -static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) -{ - const struct sched_class *class; - - for_each_class(class) { - if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) - return 1; - } - - return 0; -} /********** Helpers for find_busiest_group ************************/ /* * sd_lb_stats - Structure to store the statistics of a sched_domain @@ -3873,8 +3883,6 @@ static const struct sched_class fair_sched_class = { #ifdef CONFIG_SMP .select_task_rq = select_task_rq_fair, - .load_balance = load_balance_fair, - .move_one_task = move_one_task_fair, .rq_online = rq_online_fair, .rq_offline = rq_offline_fair, diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c index 01332bfc61a7..a8a6d8a50947 100644 --- a/kernel/sched_idletask.c +++ b/kernel/sched_idletask.c @@ -44,24 +44,6 @@ static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) { } -#ifdef CONFIG_SMP -static unsigned long -load_balance_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio) -{ - return 0; -} - -static int -move_one_task_idle(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) -{ - return 0; -} -#endif - static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued) { } @@ -119,9 +101,6 @@ static const struct sched_class idle_sched_class = { #ifdef CONFIG_SMP .select_task_rq = select_task_rq_idle, - - .load_balance = load_balance_idle, - .move_one_task = move_one_task_idle, #endif .set_curr_task = set_curr_task_idle, diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 072b3fcee8d8..502bb614e40a 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1481,24 +1481,6 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p) push_rt_tasks(rq); } -static unsigned long -load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio) -{ - /* don't touch RT tasks */ - return 0; -} - -static int -move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) -{ - /* don't touch RT tasks */ - return 0; -} - static void set_cpus_allowed_rt(struct task_struct *p, const struct cpumask *new_mask) { @@ -1746,8 +1728,6 @@ static const struct sched_class rt_sched_class = { #ifdef CONFIG_SMP .select_task_rq = select_task_rq_rt, - .load_balance = load_balance_rt, - .move_one_task = move_one_task_rt, .set_cpus_allowed = set_cpus_allowed_rt, .rq_online = rq_online_rt, .rq_offline = rq_offline_rt, -- cgit v1.2.3 From ee00e66ffff250fb0d3a789e5565462f71c7c9a7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 17:25:20 +0100 Subject: sched: Remove rq_iterator usage from load_balance_fair Since we only ever iterate the fair class, do away with this abstraction. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 80 +++++++++++++++++++---------------------------------- 1 file changed, 29 insertions(+), 51 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index faf9a2f099ab..709deb33708a 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1866,26 +1866,9 @@ static unsigned long balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct rq_iterator *iterator); + int *this_best_prio, struct cfs_rq *busiest_cfs_rq); -static unsigned long -__load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, struct sched_domain *sd, - enum cpu_idle_type idle, int *all_pinned, int *this_best_prio, - struct cfs_rq *cfs_rq) -{ - struct rq_iterator cfs_rq_iterator; - - cfs_rq_iterator.start = load_balance_start_fair; - cfs_rq_iterator.next = load_balance_next_fair; - cfs_rq_iterator.arg = cfs_rq; - - return balance_tasks(this_rq, this_cpu, busiest, - max_load_move, sd, idle, all_pinned, - this_best_prio, &cfs_rq_iterator); -} - #ifdef CONFIG_FAIR_GROUP_SCHED static unsigned long load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, @@ -1915,9 +1898,9 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, rem_load = (u64)rem_load_move * busiest_weight; rem_load = div_u64(rem_load, busiest_h_load + 1); - moved_load = __load_balance_fair(this_rq, this_cpu, busiest, + moved_load = balance_tasks(this_rq, this_cpu, busiest, rem_load, sd, idle, all_pinned, this_best_prio, - tg->cfs_rq[busiest_cpu]); + busiest_cfs_rq); if (!moved_load) continue; @@ -1940,7 +1923,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, struct sched_domain *sd, enum cpu_idle_type idle, int *all_pinned, int *this_best_prio) { - return __load_balance_fair(this_rq, this_cpu, busiest, + return balance_tasks(this_rq, this_cpu, busiest, max_load_move, sd, idle, all_pinned, this_best_prio, &busiest->cfs); } @@ -2050,53 +2033,48 @@ static unsigned long balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct rq_iterator *iterator) + int *this_best_prio, struct cfs_rq *busiest_cfs_rq) { int loops = 0, pulled = 0, pinned = 0; - struct task_struct *p; long rem_load_move = max_load_move; + struct task_struct *p, *n; if (max_load_move == 0) goto out; pinned = 1; - /* - * Start the load-balancing iterator: - */ - p = iterator->start(iterator->arg); -next: - if (!p || loops++ > sysctl_sched_nr_migrate) - goto out; + list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) { + if (loops++ > sysctl_sched_nr_migrate) + break; - if ((p->se.load.weight >> 1) > rem_load_move || - !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { - p = iterator->next(iterator->arg); - goto next; - } + if ((p->se.load.weight >> 1) > rem_load_move || + !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) + continue; - pull_task(busiest, p, this_rq, this_cpu); - pulled++; - rem_load_move -= p->se.load.weight; + pull_task(busiest, p, this_rq, this_cpu); + pulled++; + rem_load_move -= p->se.load.weight; #ifdef CONFIG_PREEMPT - /* - * NEWIDLE balancing is a source of latency, so preemptible kernels - * will stop after the first task is pulled to minimize the critical - * section. - */ - if (idle == CPU_NEWLY_IDLE) - goto out; + /* + * NEWIDLE balancing is a source of latency, so preemptible + * kernels will stop after the first task is pulled to minimize + * the critical section. + */ + if (idle == CPU_NEWLY_IDLE) + break; #endif - /* - * We only want to steal up to the prescribed amount of weighted load. - */ - if (rem_load_move > 0) { + /* + * We only want to steal up to the prescribed amount of + * weighted load. + */ + if (rem_load_move <= 0) + break; + if (p->prio < *this_best_prio) *this_best_prio = p->prio; - p = iterator->next(iterator->arg); - goto next; } out: /* -- cgit v1.2.3 From 897c395f4c94ae19302f92393a0b8304e414ee06 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 17:45:42 +0100 Subject: sched: Remove rq_iterator from move_one_task Again, since we only iterate the fair class, remove the abstraction. Since this is the last user of the rq_iterator, remove all that too. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 146 +++++++++++++--------------------------------------- 1 file changed, 36 insertions(+), 110 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 709deb33708a..e48e459da98d 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1814,54 +1814,6 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) * Fair scheduling class load-balancing methods: */ -/* - * Load-balancing iterator. Note: while the runqueue stays locked - * during the whole iteration, the current task might be - * dequeued so the iterator has to be dequeue-safe. Here we - * achieve that by always pre-iterating before returning - * the current task: - */ -static struct task_struct * -__load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next) -{ - struct task_struct *p = NULL; - struct sched_entity *se; - - if (next == &cfs_rq->tasks) - return NULL; - - se = list_entry(next, struct sched_entity, group_node); - p = task_of(se); - cfs_rq->balance_iterator = next->next; - - return p; -} - -static struct task_struct *load_balance_start_fair(void *arg) -{ - struct cfs_rq *cfs_rq = arg; - - return __load_balance_iterator(cfs_rq, cfs_rq->tasks.next); -} - -static struct task_struct *load_balance_next_fair(void *arg) -{ - struct cfs_rq *cfs_rq = arg; - - return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator); -} - -/* - * runqueue iterator, to support SMP load-balancing between different - * scheduling classes, without having to expose their internal data - * structures to the load-balancing proper: - */ -struct rq_iterator { - void *arg; - struct task_struct *(*start)(void *); - struct task_struct *(*next)(void *); -}; - static unsigned long balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, @@ -1929,42 +1881,6 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, } #endif -static int -iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle, - struct rq_iterator *iterator); - -/* - * move_one_task tries to move exactly one task from busiest to this_rq, as - * part of active balancing operations within "domain". - * Returns 1 if successful and 0 otherwise. - * - * Called with both runqueues locked. - */ -static int -move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) -{ - struct cfs_rq *busy_cfs_rq; - struct rq_iterator cfs_rq_iterator; - - cfs_rq_iterator.start = load_balance_start_fair; - cfs_rq_iterator.next = load_balance_next_fair; - - for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { - /* - * pass busy_cfs_rq argument into - * load_balance_[start|next]_fair iterators - */ - cfs_rq_iterator.arg = busy_cfs_rq; - if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle, - &cfs_rq_iterator)) - return 1; - } - - return 0; -} - /* * pull_task - move a task from a remote runqueue to the local runqueue. * Both runqueues must be locked. @@ -2029,6 +1945,42 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, return 1; } +/* + * move_one_task tries to move exactly one task from busiest to this_rq, as + * part of active balancing operations within "domain". + * Returns 1 if successful and 0 otherwise. + * + * Called with both runqueues locked. + */ +static int +move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, + struct sched_domain *sd, enum cpu_idle_type idle) +{ + struct task_struct *p, *n; + struct cfs_rq *cfs_rq; + int pinned = 0; + + for_each_leaf_cfs_rq(busiest, cfs_rq) { + list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) { + + if (!can_migrate_task(p, busiest, this_cpu, + sd, idle, &pinned)) + continue; + + pull_task(busiest, p, this_rq, this_cpu); + /* + * Right now, this is only the second place pull_task() + * is called, so we can safely collect pull_task() + * stats here rather than inside pull_task(). + */ + schedstat_inc(sd, lb_gained[idle]); + return 1; + } + } + + return 0; +} + static unsigned long balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, @@ -2126,32 +2078,6 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, return total_load_moved > 0; } -static int -iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle, - struct rq_iterator *iterator) -{ - struct task_struct *p = iterator->start(iterator->arg); - int pinned = 0; - - while (p) { - if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { - pull_task(busiest, p, this_rq, this_cpu); - /* - * Right now, this is only the second place pull_task() - * is called, so we can safely collect pull_task() - * stats here rather than inside pull_task(). - */ - schedstat_inc(sd, lb_gained[idle]); - - return 1; - } - p = iterator->next(iterator->arg); - } - - return 0; -} - /********** Helpers for find_busiest_group ************************/ /* * sd_lb_stats - Structure to store the statistics of a sched_domain -- cgit v1.2.3 From 230059de77a4e0f6afba98073e73bc9fd471506e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 17:47:12 +0100 Subject: sched: Remove from fwd decls Move code around to get rid of fwd declarations. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 127 +++++++++++++++++++++++++--------------------------- 1 file changed, 60 insertions(+), 67 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index e48e459da98d..93fccbadde23 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1814,73 +1814,6 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) * Fair scheduling class load-balancing methods: */ -static unsigned long -balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, struct sched_domain *sd, - enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct cfs_rq *busiest_cfs_rq); - - -#ifdef CONFIG_FAIR_GROUP_SCHED -static unsigned long -load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio) -{ - long rem_load_move = max_load_move; - int busiest_cpu = cpu_of(busiest); - struct task_group *tg; - - rcu_read_lock(); - update_h_load(busiest_cpu); - - list_for_each_entry_rcu(tg, &task_groups, list) { - struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu]; - unsigned long busiest_h_load = busiest_cfs_rq->h_load; - unsigned long busiest_weight = busiest_cfs_rq->load.weight; - u64 rem_load, moved_load; - - /* - * empty group - */ - if (!busiest_cfs_rq->task_weight) - continue; - - rem_load = (u64)rem_load_move * busiest_weight; - rem_load = div_u64(rem_load, busiest_h_load + 1); - - moved_load = balance_tasks(this_rq, this_cpu, busiest, - rem_load, sd, idle, all_pinned, this_best_prio, - busiest_cfs_rq); - - if (!moved_load) - continue; - - moved_load *= busiest_h_load; - moved_load = div_u64(moved_load, busiest_weight + 1); - - rem_load_move -= moved_load; - if (rem_load_move < 0) - break; - } - rcu_read_unlock(); - - return max_load_move - rem_load_move; -} -#else -static unsigned long -load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned, int *this_best_prio) -{ - return balance_tasks(this_rq, this_cpu, busiest, - max_load_move, sd, idle, all_pinned, - this_best_prio, &busiest->cfs); -} -#endif - /* * pull_task - move a task from a remote runqueue to the local runqueue. * Both runqueues must be locked. @@ -2042,6 +1975,66 @@ out: return max_load_move - rem_load_move; } +#ifdef CONFIG_FAIR_GROUP_SCHED +static unsigned long +load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned, int *this_best_prio) +{ + long rem_load_move = max_load_move; + int busiest_cpu = cpu_of(busiest); + struct task_group *tg; + + rcu_read_lock(); + update_h_load(busiest_cpu); + + list_for_each_entry_rcu(tg, &task_groups, list) { + struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu]; + unsigned long busiest_h_load = busiest_cfs_rq->h_load; + unsigned long busiest_weight = busiest_cfs_rq->load.weight; + u64 rem_load, moved_load; + + /* + * empty group + */ + if (!busiest_cfs_rq->task_weight) + continue; + + rem_load = (u64)rem_load_move * busiest_weight; + rem_load = div_u64(rem_load, busiest_h_load + 1); + + moved_load = balance_tasks(this_rq, this_cpu, busiest, + rem_load, sd, idle, all_pinned, this_best_prio, + busiest_cfs_rq); + + if (!moved_load) + continue; + + moved_load *= busiest_h_load; + moved_load = div_u64(moved_load, busiest_weight + 1); + + rem_load_move -= moved_load; + if (rem_load_move < 0) + break; + } + rcu_read_unlock(); + + return max_load_move - rem_load_move; +} +#else +static unsigned long +load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned, int *this_best_prio) +{ + return balance_tasks(this_rq, this_cpu, busiest, + max_load_move, sd, idle, all_pinned, + this_best_prio, &busiest->cfs); +} +#endif + /* * move_tasks tries to move up to max_load_move weighted load from busiest to * this_rq, as part of a balancing operation within domain "sd". -- cgit v1.2.3 From baa8c1102f0cd86e69c1497d61d2ee177e663663 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 17 Dec 2009 18:10:09 +0100 Subject: sched: Add a lock break for PREEMPT=y Since load-balancing can hold rq->locks for quite a long while, allow breaking out early when there is lock contention. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 93fccbadde23..65d08207e925 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2065,6 +2065,10 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, */ if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) break; + + if (raw_spin_is_contended(&this_rq->lock) || + raw_spin_is_contended(&busiest->lock)) + break; #endif } while (load_moved && max_load_move > total_load_moved); -- cgit v1.2.3 From 1af3ed3ddf27499c3f57662c4c29871e2b95e5f9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 23 Dec 2009 15:10:31 +0100 Subject: sched: Unify load_balance{,_newidle}() load_balance() and load_balance_newidle() look remarkably similar, one key point they differ in is the condition on when to active balance. So split out that logic into a separate function. One side effect is that previously load_balance_newidle() used to fail and return -1 under these conditions, whereas now it doesn't. I've not yet fully figured out the whole -1 return case for either load_balance{,_newidle}(). Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 115 +++++++++++++++++++++++++++------------------------- 1 file changed, 59 insertions(+), 56 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 65d08207e925..10408323794e 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2816,6 +2816,39 @@ find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, /* Working cpumask for load_balance and load_balance_newidle. */ static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask); +static int need_active_balance(struct sched_domain *sd, int sd_idle, int idle) +{ + if (idle == CPU_NEWLY_IDLE) { + /* + * The only task running in a non-idle cpu can be moved to this + * cpu in an attempt to completely freeup the other CPU + * package. + * + * The package power saving logic comes from + * find_busiest_group(). If there are no imbalance, then + * f_b_g() will return NULL. However when sched_mc={1,2} then + * f_b_g() will select a group from which a running task may be + * pulled to this cpu in order to make the other package idle. + * If there is no opportunity to make a package idle and if + * there are no imbalance, then f_b_g() will return NULL and no + * action will be taken in load_balance_newidle(). + * + * Under normal task pull operation due to imbalance, there + * will be more than one task in the source run queue and + * move_tasks() will succeed. ld_moved will be true and this + * active balance code will not be triggered. + */ + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return 0; + + if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) + return 0; + } + + return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2); +} + /* * Check this_cpu to ensure it is balanced within domain. Attempt to move * tasks if there is an imbalance. @@ -2902,8 +2935,7 @@ redo: schedstat_inc(sd, lb_failed[idle]); sd->nr_balance_failed++; - if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { - + if (need_active_balance(sd, sd_idle, idle)) { raw_spin_lock_irqsave(&busiest->lock, flags); /* don't kick the migration_thread, if the curr @@ -3049,66 +3081,37 @@ redo: int active_balance = 0; schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - - if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP) - return -1; + sd->nr_balance_failed++; - if (sd->nr_balance_failed++ < 2) - return -1; + if (need_active_balance(sd, sd_idle, CPU_NEWLY_IDLE)) { + double_lock_balance(this_rq, busiest); - /* - * The only task running in a non-idle cpu can be moved to this - * cpu in an attempt to completely freeup the other CPU - * package. The same method used to move task in load_balance() - * have been extended for load_balance_newidle() to speedup - * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2) - * - * The package power saving logic comes from - * find_busiest_group(). If there are no imbalance, then - * f_b_g() will return NULL. However when sched_mc={1,2} then - * f_b_g() will select a group from which a running task may be - * pulled to this cpu in order to make the other package idle. - * If there is no opportunity to make a package idle and if - * there are no imbalance, then f_b_g() will return NULL and no - * action will be taken in load_balance_newidle(). - * - * Under normal task pull operation due to imbalance, there - * will be more than one task in the source run queue and - * move_tasks() will succeed. ld_moved will be true and this - * active balance code will not be triggered. - */ + /* + * don't kick the migration_thread, if the curr + * task on busiest cpu can't be moved to this_cpu + */ + if (!cpumask_test_cpu(this_cpu, + &busiest->curr->cpus_allowed)) { + double_unlock_balance(this_rq, busiest); + all_pinned = 1; + return ld_moved; + } - /* Lock busiest in correct order while this_rq is held */ - double_lock_balance(this_rq, busiest); + if (!busiest->active_balance) { + busiest->active_balance = 1; + busiest->push_cpu = this_cpu; + active_balance = 1; + } - /* - * don't kick the migration_thread, if the curr - * task on busiest cpu can't be moved to this_cpu - */ - if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) { double_unlock_balance(this_rq, busiest); - all_pinned = 1; - return ld_moved; - } - - if (!busiest->active_balance) { - busiest->active_balance = 1; - busiest->push_cpu = this_cpu; - active_balance = 1; + /* + * Should not call ttwu while holding a rq->lock + */ + raw_spin_unlock(&this_rq->lock); + if (active_balance) + wake_up_process(busiest->migration_thread); + raw_spin_lock(&this_rq->lock); } - - double_unlock_balance(this_rq, busiest); - /* - * Should not call ttwu while holding a rq->lock - */ - raw_spin_unlock(&this_rq->lock); - if (active_balance) - wake_up_process(busiest->migration_thread); - raw_spin_lock(&this_rq->lock); - } else sd->nr_balance_failed = 0; -- cgit v1.2.3 From f492e12ef050e02bf0185b6b57874992591b9be1 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 23 Dec 2009 15:29:42 +0100 Subject: sched: Remove load_balance_newidle() The two functions: load_balance{,_newidle}() are very similar, with the following differences: - rq->lock usage - sb->balance_interval updates - *balance check So remove the load_balance_newidle() call with load_balance(.idle = CPU_NEWLY_IDLE), explicitly unlock the rq->lock before calling (would be done by double_lock_balance() anyway), and ignore the other differences for now. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 135 +++++----------------------------------------------- 1 file changed, 13 insertions(+), 122 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 10408323794e..de5ab1239e04 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -3009,125 +3009,6 @@ out: return ld_moved; } -/* - * Check this_cpu to ensure it is balanced within domain. Attempt to move - * tasks if there is an imbalance. - * - * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). - * this_rq is locked. - */ -static int -load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) -{ - struct sched_group *group; - struct rq *busiest = NULL; - unsigned long imbalance; - int ld_moved = 0; - int sd_idle = 0; - int all_pinned = 0; - struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask); - - cpumask_copy(cpus, cpu_active_mask); - - /* - * When power savings policy is enabled for the parent domain, idle - * sibling can pick up load irrespective of busy siblings. In this case, - * let the state of idle sibling percolate up as IDLE, instead of - * portraying it as CPU_NOT_IDLE. - */ - if (sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - sd_idle = 1; - - schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); -redo: - update_shares_locked(this_rq, sd); - group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, - &sd_idle, cpus, NULL); - if (!group) { - schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); - - ld_moved = 0; - if (busiest->nr_running > 1) { - /* Attempt to move tasks */ - double_lock_balance(this_rq, busiest); - /* this_rq->clock is already updated */ - update_rq_clock(busiest); - ld_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, CPU_NEWLY_IDLE, - &all_pinned); - double_unlock_balance(this_rq, busiest); - - if (unlikely(all_pinned)) { - cpumask_clear_cpu(cpu_of(busiest), cpus); - if (!cpumask_empty(cpus)) - goto redo; - } - } - - if (!ld_moved) { - int active_balance = 0; - - schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); - sd->nr_balance_failed++; - - if (need_active_balance(sd, sd_idle, CPU_NEWLY_IDLE)) { - double_lock_balance(this_rq, busiest); - - /* - * don't kick the migration_thread, if the curr - * task on busiest cpu can't be moved to this_cpu - */ - if (!cpumask_test_cpu(this_cpu, - &busiest->curr->cpus_allowed)) { - double_unlock_balance(this_rq, busiest); - all_pinned = 1; - return ld_moved; - } - - if (!busiest->active_balance) { - busiest->active_balance = 1; - busiest->push_cpu = this_cpu; - active_balance = 1; - } - - double_unlock_balance(this_rq, busiest); - /* - * Should not call ttwu while holding a rq->lock - */ - raw_spin_unlock(&this_rq->lock); - if (active_balance) - wake_up_process(busiest->migration_thread); - raw_spin_lock(&this_rq->lock); - } - } else - sd->nr_balance_failed = 0; - - update_shares_locked(this_rq, sd); - return ld_moved; - -out_balanced: - schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - sd->nr_balance_failed = 0; - - return 0; -} - /* * idle_balance is called by schedule() if this_cpu is about to become * idle. Attempts to pull tasks from other CPUs. @@ -3143,16 +3024,23 @@ static void idle_balance(int this_cpu, struct rq *this_rq) if (this_rq->avg_idle < sysctl_sched_migration_cost) return; + /* + * Drop the rq->lock, but keep IRQ/preempt disabled. + */ + raw_spin_unlock(&this_rq->lock); + for_each_domain(this_cpu, sd) { unsigned long interval; + int balance = 1; if (!(sd->flags & SD_LOAD_BALANCE)) continue; - if (sd->flags & SD_BALANCE_NEWIDLE) + if (sd->flags & SD_BALANCE_NEWIDLE) { /* If we've pulled tasks over stop searching: */ - pulled_task = load_balance_newidle(this_cpu, this_rq, - sd); + pulled_task = load_balance(this_cpu, this_rq, + sd, CPU_NEWLY_IDLE, &balance); + } interval = msecs_to_jiffies(sd->balance_interval); if (time_after(next_balance, sd->last_balance + interval)) @@ -3162,6 +3050,9 @@ static void idle_balance(int this_cpu, struct rq *this_rq) break; } } + + raw_spin_lock(&this_rq->lock); + if (pulled_task || time_after(jiffies, this_rq->next_balance)) { /* * We are going idle. next_balance may be set based on -- cgit v1.2.3 From 8f190fb3f7a405682666d3723f6ec370b5afe4da Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 24 Dec 2009 14:18:21 +0100 Subject: sched: Assume *balance is valid Since all load_balance() callers will have !NULL balance parameters we can now assume so and remove a few checks. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index de5ab1239e04..0b482f5b5b3b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2465,7 +2465,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, * to do the newly idle load balance. */ if (idle != CPU_NEWLY_IDLE && local_group && - balance_cpu != this_cpu && balance) { + balance_cpu != this_cpu) { *balance = 0; return; } @@ -2528,7 +2528,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, update_sg_lb_stats(sd, group, this_cpu, idle, load_idx, sd_idle, local_group, cpus, balance, &sgs); - if (local_group && balance && !(*balance)) + if (local_group && !(*balance)) return; sds->total_load += sgs.group_load; @@ -2720,7 +2720,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, * 5) The imbalance is within the specified limit. * 6) Any rebalance would lead to ping-pong */ - if (balance && !(*balance)) + if (!(*balance)) goto ret; if (!sds.busiest || sds.busiest_nr_running == 0) -- cgit v1.2.3 From 871e35bc9733f273eaf5ceb69bbd0423b58e5285 Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Wed, 20 Jan 2010 14:02:44 -0600 Subject: sched: Fix the place where group powers are updated We want to update the sched_group_powers when balance_cpu == this_cpu. Currently the group powers are updated only if the balance_cpu is the first CPU in the local group. But balance_cpu = this_cpu could also be the first idle cpu in the group. Hence fix the place where the group powers are updated. Signed-off-by: Gautham R Shenoy Signed-off-by: Joel Schopp Signed-off-by: Peter Zijlstra LKML-Reference: <1264017764.5717.127.camel@jschopp-laptop> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 0b482f5b5b3b..22231ccb2f98 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2418,11 +2418,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, unsigned long sum_avg_load_per_task; unsigned long avg_load_per_task; - if (local_group) { + if (local_group) balance_cpu = group_first_cpu(group); - if (balance_cpu == this_cpu) - update_group_power(sd, this_cpu); - } /* Tally up the load of all CPUs in the group */ sum_avg_load_per_task = avg_load_per_task = 0; @@ -2470,6 +2467,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, return; } + update_group_power(sd, this_cpu); + /* Adjust by relative CPU power of the group */ sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; -- cgit v1.2.3 From 7c9414385ebfdd87cc542d4e7e3bb0dbb2d3ce25 Mon Sep 17 00:00:00 2001 From: Dhaval Giani Date: Wed, 20 Jan 2010 13:26:18 +0100 Subject: sched: Remove USER_SCHED Remove the USER_SCHED feature. It has been scheduled to be removed in 2.6.34 as per http://marc.info/?l=linux-kernel&m=125728479022976&w=2 Signed-off-by: Dhaval Giani Signed-off-by: Peter Zijlstra LKML-Reference: <1263990378.24844.3.camel@localhost> Signed-off-by: Ingo Molnar --- Documentation/feature-removal-schedule.txt | 15 -- include/linux/sched.h | 14 +- init/Kconfig | 81 +++----- kernel/ksysfs.c | 8 - kernel/sched.c | 114 +---------- kernel/sys.c | 5 - kernel/user.c | 305 ----------------------------- 7 files changed, 38 insertions(+), 504 deletions(-) (limited to 'kernel') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 870d190fe617..04a3fc3d139b 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -6,21 +6,6 @@ be removed from this file. --------------------------- -What: USER_SCHED -When: 2.6.34 - -Why: USER_SCHED was implemented as a proof of concept for group scheduling. - The effect of USER_SCHED can already be achieved from userspace with - the help of libcgroup. The removal of USER_SCHED will also simplify - the scheduler code with the removal of one major ifdef. There are also - issues USER_SCHED has with USER_NS. A decision was taken not to fix - those and instead remove USER_SCHED. Also new group scheduling - features will not be implemented for USER_SCHED. - -Who: Dhaval Giani - ---------------------------- - What: PRISM54 When: 2.6.34 diff --git a/include/linux/sched.h b/include/linux/sched.h index 50d685cde70e..8b079735ae5f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -731,14 +731,6 @@ struct user_struct { uid_t uid; struct user_namespace *user_ns; -#ifdef CONFIG_USER_SCHED - struct task_group *tg; -#ifdef CONFIG_SYSFS - struct kobject kobj; - struct delayed_work work; -#endif -#endif - #ifdef CONFIG_PERF_EVENTS atomic_long_t locked_vm; #endif @@ -2502,13 +2494,9 @@ extern long sched_getaffinity(pid_t pid, struct cpumask *mask); extern void normalize_rt_tasks(void); -#ifdef CONFIG_GROUP_SCHED +#ifdef CONFIG_CGROUP_SCHED extern struct task_group init_task_group; -#ifdef CONFIG_USER_SCHED -extern struct task_group root_task_group; -extern void set_tg_uid(struct user_struct *user); -#endif extern struct task_group *sched_create_group(struct task_group *parent); extern void sched_destroy_group(struct task_group *tg); diff --git a/init/Kconfig b/init/Kconfig index a23da9f01803..e9fa3007a6fc 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -435,57 +435,6 @@ config LOG_BUF_SHIFT config HAVE_UNSTABLE_SCHED_CLOCK bool -config GROUP_SCHED - bool "Group CPU scheduler" - depends on EXPERIMENTAL - default n - help - This feature lets CPU scheduler recognize task groups and control CPU - bandwidth allocation to such task groups. - In order to create a group from arbitrary set of processes, use - CONFIG_CGROUPS. (See Control Group support.) - -config FAIR_GROUP_SCHED - bool "Group scheduling for SCHED_OTHER" - depends on GROUP_SCHED - default GROUP_SCHED - -config RT_GROUP_SCHED - bool "Group scheduling for SCHED_RR/FIFO" - depends on EXPERIMENTAL - depends on GROUP_SCHED - default n - help - This feature lets you explicitly allocate real CPU bandwidth - to users or control groups (depending on the "Basis for grouping tasks" - setting below. If enabled, it will also make it impossible to - schedule realtime tasks for non-root users until you allocate - realtime bandwidth for them. - See Documentation/scheduler/sched-rt-group.txt for more information. - -choice - depends on GROUP_SCHED - prompt "Basis for grouping tasks" - default USER_SCHED - -config USER_SCHED - bool "user id" - help - This option will choose userid as the basis for grouping - tasks, thus providing equal CPU bandwidth to each user. - -config CGROUP_SCHED - bool "Control groups" - depends on CGROUPS - help - This option allows you to create arbitrary task groups - using the "cgroup" pseudo filesystem and control - the cpu bandwidth allocated to each such task group. - Refer to Documentation/cgroups/cgroups.txt for more - information on "cgroup" pseudo filesystem. - -endchoice - menuconfig CGROUPS boolean "Control Group support" help @@ -606,6 +555,36 @@ config CGROUP_MEM_RES_CTLR_SWAP Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page size is 4096bytes, 512k per 1Gbytes of swap. +menuconfig CGROUP_SCHED + bool "Group CPU scheduler" + depends on EXPERIMENTAL && CGROUPS + default n + help + This feature lets CPU scheduler recognize task groups and control CPU + bandwidth allocation to such task groups. It uses cgroups to group + tasks. + +if CGROUP_SCHED +config FAIR_GROUP_SCHED + bool "Group scheduling for SCHED_OTHER" + depends on CGROUP_SCHED + default CGROUP_SCHED + +config RT_GROUP_SCHED + bool "Group scheduling for SCHED_RR/FIFO" + depends on EXPERIMENTAL + depends on CGROUP_SCHED + default n + help + This feature lets you explicitly allocate real CPU bandwidth + to users or control groups (depending on the "Basis for grouping tasks" + setting below. If enabled, it will also make it impossible to + schedule realtime tasks for non-root users until you allocate + realtime bandwidth for them. + See Documentation/scheduler/sched-rt-group.txt for more information. + +endif #CGROUP_SCHED + endif # CGROUPS config MM_OWNER diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 3feaf5a74514..6b1ccc3f0205 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -197,16 +197,8 @@ static int __init ksysfs_init(void) goto group_exit; } - /* create the /sys/kernel/uids/ directory */ - error = uids_sysfs_init(); - if (error) - goto notes_exit; - return 0; -notes_exit: - if (notes_size > 0) - sysfs_remove_bin_file(kernel_kobj, ¬es_attr); group_exit: sysfs_remove_group(kernel_kobj, &kernel_attr_group); kset_exit: diff --git a/kernel/sched.c b/kernel/sched.c index c0be07932a8d..41e76d325648 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -233,7 +233,7 @@ static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) */ static DEFINE_MUTEX(sched_domains_mutex); -#ifdef CONFIG_GROUP_SCHED +#ifdef CONFIG_CGROUP_SCHED #include @@ -243,13 +243,7 @@ static LIST_HEAD(task_groups); /* task group related information */ struct task_group { -#ifdef CONFIG_CGROUP_SCHED struct cgroup_subsys_state css; -#endif - -#ifdef CONFIG_USER_SCHED - uid_t uid; -#endif #ifdef CONFIG_FAIR_GROUP_SCHED /* schedulable entities of this group on each cpu */ @@ -274,35 +268,7 @@ struct task_group { struct list_head children; }; -#ifdef CONFIG_USER_SCHED - -/* Helper function to pass uid information to create_sched_user() */ -void set_tg_uid(struct user_struct *user) -{ - user->tg->uid = user->uid; -} - -/* - * Root task group. - * Every UID task group (including init_task_group aka UID-0) will - * be a child to this group. - */ -struct task_group root_task_group; - -#ifdef CONFIG_FAIR_GROUP_SCHED -/* Default task group's sched entity on each cpu */ -static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); -/* Default task group's cfs_rq on each cpu */ -static DEFINE_PER_CPU_SHARED_ALIGNED(struct cfs_rq, init_tg_cfs_rq); -#endif /* CONFIG_FAIR_GROUP_SCHED */ - -#ifdef CONFIG_RT_GROUP_SCHED -static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); -static DEFINE_PER_CPU_SHARED_ALIGNED(struct rt_rq, init_rt_rq_var); -#endif /* CONFIG_RT_GROUP_SCHED */ -#else /* !CONFIG_USER_SCHED */ #define root_task_group init_task_group -#endif /* CONFIG_USER_SCHED */ /* task_group_lock serializes add/remove of task groups and also changes to * a task group's cpu shares. @@ -318,11 +284,7 @@ static int root_task_group_empty(void) } #endif -#ifdef CONFIG_USER_SCHED -# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) -#else /* !CONFIG_USER_SCHED */ # define INIT_TASK_GROUP_LOAD NICE_0_LOAD -#endif /* CONFIG_USER_SCHED */ /* * A weight of 0 or 1 can cause arithmetics problems. @@ -348,11 +310,7 @@ static inline struct task_group *task_group(struct task_struct *p) { struct task_group *tg; -#ifdef CONFIG_USER_SCHED - rcu_read_lock(); - tg = __task_cred(p)->user->tg; - rcu_read_unlock(); -#elif defined(CONFIG_CGROUP_SCHED) +#ifdef CONFIG_CGROUP_SCHED tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id), struct task_group, css); #else @@ -383,7 +341,7 @@ static inline struct task_group *task_group(struct task_struct *p) return NULL; } -#endif /* CONFIG_GROUP_SCHED */ +#endif /* CONFIG_CGROUP_SCHED */ /* CFS-related fields in a runqueue */ struct cfs_rq { @@ -7678,9 +7636,6 @@ void __init sched_init(void) #ifdef CONFIG_RT_GROUP_SCHED alloc_size += 2 * nr_cpu_ids * sizeof(void **); #endif -#ifdef CONFIG_USER_SCHED - alloc_size *= 2; -#endif #ifdef CONFIG_CPUMASK_OFFSTACK alloc_size += num_possible_cpus() * cpumask_size(); #endif @@ -7694,13 +7649,6 @@ void __init sched_init(void) init_task_group.cfs_rq = (struct cfs_rq **)ptr; ptr += nr_cpu_ids * sizeof(void **); -#ifdef CONFIG_USER_SCHED - root_task_group.se = (struct sched_entity **)ptr; - ptr += nr_cpu_ids * sizeof(void **); - - root_task_group.cfs_rq = (struct cfs_rq **)ptr; - ptr += nr_cpu_ids * sizeof(void **); -#endif /* CONFIG_USER_SCHED */ #endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED init_task_group.rt_se = (struct sched_rt_entity **)ptr; @@ -7709,13 +7657,6 @@ void __init sched_init(void) init_task_group.rt_rq = (struct rt_rq **)ptr; ptr += nr_cpu_ids * sizeof(void **); -#ifdef CONFIG_USER_SCHED - root_task_group.rt_se = (struct sched_rt_entity **)ptr; - ptr += nr_cpu_ids * sizeof(void **); - - root_task_group.rt_rq = (struct rt_rq **)ptr; - ptr += nr_cpu_ids * sizeof(void **); -#endif /* CONFIG_USER_SCHED */ #endif /* CONFIG_RT_GROUP_SCHED */ #ifdef CONFIG_CPUMASK_OFFSTACK for_each_possible_cpu(i) { @@ -7735,22 +7676,13 @@ void __init sched_init(void) #ifdef CONFIG_RT_GROUP_SCHED init_rt_bandwidth(&init_task_group.rt_bandwidth, global_rt_period(), global_rt_runtime()); -#ifdef CONFIG_USER_SCHED - init_rt_bandwidth(&root_task_group.rt_bandwidth, - global_rt_period(), RUNTIME_INF); -#endif /* CONFIG_USER_SCHED */ #endif /* CONFIG_RT_GROUP_SCHED */ -#ifdef CONFIG_GROUP_SCHED +#ifdef CONFIG_CGROUP_SCHED list_add(&init_task_group.list, &task_groups); INIT_LIST_HEAD(&init_task_group.children); -#ifdef CONFIG_USER_SCHED - INIT_LIST_HEAD(&root_task_group.children); - init_task_group.parent = &root_task_group; - list_add(&init_task_group.siblings, &root_task_group.children); -#endif /* CONFIG_USER_SCHED */ -#endif /* CONFIG_GROUP_SCHED */ +#endif /* CONFIG_CGROUP_SCHED */ #if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long), @@ -7790,25 +7722,6 @@ void __init sched_init(void) * directly in rq->cfs (i.e init_task_group->se[] = NULL). */ init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL); -#elif defined CONFIG_USER_SCHED - root_task_group.shares = NICE_0_LOAD; - init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL); - /* - * In case of task-groups formed thr' the user id of tasks, - * init_task_group represents tasks belonging to root user. - * Hence it forms a sibling of all subsequent groups formed. - * In this case, init_task_group gets only a fraction of overall - * system cpu resource, based on the weight assigned to root - * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished - * by letting tasks of init_task_group sit in a separate cfs_rq - * (init_tg_cfs_rq) and having one entity represent this group of - * tasks in rq->cfs (i.e init_task_group->se[] != NULL). - */ - init_tg_cfs_entry(&init_task_group, - &per_cpu(init_tg_cfs_rq, i), - &per_cpu(init_sched_entity, i), i, 1, - root_task_group.se[i]); - #endif #endif /* CONFIG_FAIR_GROUP_SCHED */ @@ -7817,12 +7730,6 @@ void __init sched_init(void) INIT_LIST_HEAD(&rq->leaf_rt_rq_list); #ifdef CONFIG_CGROUP_SCHED init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL); -#elif defined CONFIG_USER_SCHED - init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL); - init_tg_rt_entry(&init_task_group, - &per_cpu(init_rt_rq_var, i), - &per_cpu(init_sched_rt_entity, i), i, 1, - root_task_group.rt_se[i]); #endif #endif @@ -8218,7 +8125,7 @@ static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) } #endif /* CONFIG_RT_GROUP_SCHED */ -#ifdef CONFIG_GROUP_SCHED +#ifdef CONFIG_CGROUP_SCHED static void free_sched_group(struct task_group *tg) { free_fair_sched_group(tg); @@ -8327,7 +8234,7 @@ void sched_move_task(struct task_struct *tsk) task_rq_unlock(rq, &flags); } -#endif /* CONFIG_GROUP_SCHED */ +#endif /* CONFIG_CGROUP_SCHED */ #ifdef CONFIG_FAIR_GROUP_SCHED static void __set_se_shares(struct sched_entity *se, unsigned long shares) @@ -8469,13 +8376,6 @@ static int tg_schedulable(struct task_group *tg, void *data) runtime = d->rt_runtime; } -#ifdef CONFIG_USER_SCHED - if (tg == &root_task_group) { - period = global_rt_period(); - runtime = global_rt_runtime(); - } -#endif - /* * Cannot have more runtime than the period. */ diff --git a/kernel/sys.c b/kernel/sys.c index 26a6b73a6b85..f75bf0936f47 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -569,11 +569,6 @@ static int set_user(struct cred *new) if (!new_user) return -EAGAIN; - if (!task_can_switch_user(new_user, current)) { - free_uid(new_user); - return -EINVAL; - } - if (atomic_read(&new_user->processes) >= current->signal->rlim[RLIMIT_NPROC].rlim_cur && new_user != INIT_USER) { diff --git a/kernel/user.c b/kernel/user.c index 46d0165ca70c..766467b3bcb7 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -56,9 +56,6 @@ struct user_struct root_user = { .sigpending = ATOMIC_INIT(0), .locked_shm = 0, .user_ns = &init_user_ns, -#ifdef CONFIG_USER_SCHED - .tg = &init_task_group, -#endif }; /* @@ -75,268 +72,6 @@ static void uid_hash_remove(struct user_struct *up) put_user_ns(up->user_ns); } -#ifdef CONFIG_USER_SCHED - -static void sched_destroy_user(struct user_struct *up) -{ - sched_destroy_group(up->tg); -} - -static int sched_create_user(struct user_struct *up) -{ - int rc = 0; - - up->tg = sched_create_group(&root_task_group); - if (IS_ERR(up->tg)) - rc = -ENOMEM; - - set_tg_uid(up); - - return rc; -} - -#else /* CONFIG_USER_SCHED */ - -static void sched_destroy_user(struct user_struct *up) { } -static int sched_create_user(struct user_struct *up) { return 0; } - -#endif /* CONFIG_USER_SCHED */ - -#if defined(CONFIG_USER_SCHED) && defined(CONFIG_SYSFS) - -static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) -{ - struct user_struct *user; - struct hlist_node *h; - - hlist_for_each_entry(user, h, hashent, uidhash_node) { - if (user->uid == uid) { - /* possibly resurrect an "almost deleted" object */ - if (atomic_inc_return(&user->__count) == 1) - cancel_delayed_work(&user->work); - return user; - } - } - - return NULL; -} - -static struct kset *uids_kset; /* represents the /sys/kernel/uids/ directory */ -static DEFINE_MUTEX(uids_mutex); - -static inline void uids_mutex_lock(void) -{ - mutex_lock(&uids_mutex); -} - -static inline void uids_mutex_unlock(void) -{ - mutex_unlock(&uids_mutex); -} - -/* uid directory attributes */ -#ifdef CONFIG_FAIR_GROUP_SCHED -static ssize_t cpu_shares_show(struct kobject *kobj, - struct kobj_attribute *attr, - char *buf) -{ - struct user_struct *up = container_of(kobj, struct user_struct, kobj); - - return sprintf(buf, "%lu\n", sched_group_shares(up->tg)); -} - -static ssize_t cpu_shares_store(struct kobject *kobj, - struct kobj_attribute *attr, - const char *buf, size_t size) -{ - struct user_struct *up = container_of(kobj, struct user_struct, kobj); - unsigned long shares; - int rc; - - sscanf(buf, "%lu", &shares); - - rc = sched_group_set_shares(up->tg, shares); - - return (rc ? rc : size); -} - -static struct kobj_attribute cpu_share_attr = - __ATTR(cpu_share, 0644, cpu_shares_show, cpu_shares_store); -#endif - -#ifdef CONFIG_RT_GROUP_SCHED -static ssize_t cpu_rt_runtime_show(struct kobject *kobj, - struct kobj_attribute *attr, - char *buf) -{ - struct user_struct *up = container_of(kobj, struct user_struct, kobj); - - return sprintf(buf, "%ld\n", sched_group_rt_runtime(up->tg)); -} - -static ssize_t cpu_rt_runtime_store(struct kobject *kobj, - struct kobj_attribute *attr, - const char *buf, size_t size) -{ - struct user_struct *up = container_of(kobj, struct user_struct, kobj); - unsigned long rt_runtime; - int rc; - - sscanf(buf, "%ld", &rt_runtime); - - rc = sched_group_set_rt_runtime(up->tg, rt_runtime); - - return (rc ? rc : size); -} - -static struct kobj_attribute cpu_rt_runtime_attr = - __ATTR(cpu_rt_runtime, 0644, cpu_rt_runtime_show, cpu_rt_runtime_store); - -static ssize_t cpu_rt_period_show(struct kobject *kobj, - struct kobj_attribute *attr, - char *buf) -{ - struct user_struct *up = container_of(kobj, struct user_struct, kobj); - - return sprintf(buf, "%lu\n", sched_group_rt_period(up->tg)); -} - -static ssize_t cpu_rt_period_store(struct kobject *kobj, - struct kobj_attribute *attr, - const char *buf, size_t size) -{ - struct user_struct *up = container_of(kobj, struct user_struct, kobj); - unsigned long rt_period; - int rc; - - sscanf(buf, "%lu", &rt_period); - - rc = sched_group_set_rt_period(up->tg, rt_period); - - return (rc ? rc : size); -} - -static struct kobj_attribute cpu_rt_period_attr = - __ATTR(cpu_rt_period, 0644, cpu_rt_period_show, cpu_rt_period_store); -#endif - -/* default attributes per uid directory */ -static struct attribute *uids_attributes[] = { -#ifdef CONFIG_FAIR_GROUP_SCHED - &cpu_share_attr.attr, -#endif -#ifdef CONFIG_RT_GROUP_SCHED - &cpu_rt_runtime_attr.attr, - &cpu_rt_period_attr.attr, -#endif - NULL -}; - -/* the lifetime of user_struct is not managed by the core (now) */ -static void uids_release(struct kobject *kobj) -{ - return; -} - -static struct kobj_type uids_ktype = { - .sysfs_ops = &kobj_sysfs_ops, - .default_attrs = uids_attributes, - .release = uids_release, -}; - -/* - * Create /sys/kernel/uids//cpu_share file for this user - * We do not create this file for users in a user namespace (until - * sysfs tagging is implemented). - * - * See Documentation/scheduler/sched-design-CFS.txt for ramifications. - */ -static int uids_user_create(struct user_struct *up) -{ - struct kobject *kobj = &up->kobj; - int error; - - memset(kobj, 0, sizeof(struct kobject)); - if (up->user_ns != &init_user_ns) - return 0; - kobj->kset = uids_kset; - error = kobject_init_and_add(kobj, &uids_ktype, NULL, "%d", up->uid); - if (error) { - kobject_put(kobj); - goto done; - } - - kobject_uevent(kobj, KOBJ_ADD); -done: - return error; -} - -/* create these entries in sysfs: - * "/sys/kernel/uids" directory - * "/sys/kernel/uids/0" directory (for root user) - * "/sys/kernel/uids/0/cpu_share" file (for root user) - */ -int __init uids_sysfs_init(void) -{ - uids_kset = kset_create_and_add("uids", NULL, kernel_kobj); - if (!uids_kset) - return -ENOMEM; - - return uids_user_create(&root_user); -} - -/* delayed work function to remove sysfs directory for a user and free up - * corresponding structures. - */ -static void cleanup_user_struct(struct work_struct *w) -{ - struct user_struct *up = container_of(w, struct user_struct, work.work); - unsigned long flags; - int remove_user = 0; - - /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del() - * atomic. - */ - uids_mutex_lock(); - - spin_lock_irqsave(&uidhash_lock, flags); - if (atomic_read(&up->__count) == 0) { - uid_hash_remove(up); - remove_user = 1; - } - spin_unlock_irqrestore(&uidhash_lock, flags); - - if (!remove_user) - goto done; - - if (up->user_ns == &init_user_ns) { - kobject_uevent(&up->kobj, KOBJ_REMOVE); - kobject_del(&up->kobj); - kobject_put(&up->kobj); - } - - sched_destroy_user(up); - key_put(up->uid_keyring); - key_put(up->session_keyring); - kmem_cache_free(uid_cachep, up); - -done: - uids_mutex_unlock(); -} - -/* IRQs are disabled and uidhash_lock is held upon function entry. - * IRQ state (as stored in flags) is restored and uidhash_lock released - * upon function exit. - */ -static void free_user(struct user_struct *up, unsigned long flags) -{ - INIT_DELAYED_WORK(&up->work, cleanup_user_struct); - schedule_delayed_work(&up->work, msecs_to_jiffies(1000)); - spin_unlock_irqrestore(&uidhash_lock, flags); -} - -#else /* CONFIG_USER_SCHED && CONFIG_SYSFS */ - static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) { struct user_struct *user; @@ -352,11 +87,6 @@ static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) return NULL; } -int uids_sysfs_init(void) { return 0; } -static inline int uids_user_create(struct user_struct *up) { return 0; } -static inline void uids_mutex_lock(void) { } -static inline void uids_mutex_unlock(void) { } - /* IRQs are disabled and uidhash_lock is held upon function entry. * IRQ state (as stored in flags) is restored and uidhash_lock released * upon function exit. @@ -365,32 +95,11 @@ static void free_user(struct user_struct *up, unsigned long flags) { uid_hash_remove(up); spin_unlock_irqrestore(&uidhash_lock, flags); - sched_destroy_user(up); key_put(up->uid_keyring); key_put(up->session_keyring); kmem_cache_free(uid_cachep, up); } -#endif - -#if defined(CONFIG_RT_GROUP_SCHED) && defined(CONFIG_USER_SCHED) -/* - * We need to check if a setuid can take place. This function should be called - * before successfully completing the setuid. - */ -int task_can_switch_user(struct user_struct *up, struct task_struct *tsk) -{ - - return sched_rt_can_attach(up->tg, tsk); - -} -#else -int task_can_switch_user(struct user_struct *up, struct task_struct *tsk) -{ - return 1; -} -#endif - /* * Locate the user_struct for the passed UID. If found, take a ref on it. The * caller must undo that ref with free_uid(). @@ -431,8 +140,6 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid) /* Make uid_hash_find() + uids_user_create() + uid_hash_insert() * atomic. */ - uids_mutex_lock(); - spin_lock_irq(&uidhash_lock); up = uid_hash_find(uid, hashent); spin_unlock_irq(&uidhash_lock); @@ -445,14 +152,8 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid) new->uid = uid; atomic_set(&new->__count, 1); - if (sched_create_user(new) < 0) - goto out_free_user; - new->user_ns = get_user_ns(ns); - if (uids_user_create(new)) - goto out_destoy_sched; - /* * Before adding this, check whether we raced * on adding the same user already.. @@ -475,17 +176,11 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid) spin_unlock_irq(&uidhash_lock); } - uids_mutex_unlock(); - return up; -out_destoy_sched: - sched_destroy_user(new); put_user_ns(new->user_ns); -out_free_user: kmem_cache_free(uid_cachep, new); out_unlock: - uids_mutex_unlock(); return NULL; } -- cgit v1.2.3 From ea87bb7853168434f4a82426dd1ea8421f9e604d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 20 Jan 2010 20:58:57 +0000 Subject: sched: Extend enqueue_task to allow head queueing The ability of enqueueing a task to the head of a SCHED_FIFO priority list is required to fix some violations of POSIX scheduling policy. Extend the related functions with a "head" argument. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Tested-by: Carsten Emde Tested-by: Mathias Weber LKML-Reference: <20100120171629.734886007@linutronix.de> --- include/linux/sched.h | 3 ++- kernel/sched.c | 13 +++++++------ kernel/sched_fair.c | 3 ++- kernel/sched_rt.c | 3 ++- 4 files changed, 13 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/include/linux/sched.h b/include/linux/sched.h index 8b079735ae5f..b35c0c7130c8 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1067,7 +1067,8 @@ struct sched_domain; struct sched_class { const struct sched_class *next; - void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup); + void (*enqueue_task) (struct rq *rq, struct task_struct *p, int wakeup, + bool head); void (*dequeue_task) (struct rq *rq, struct task_struct *p, int sleep); void (*yield_task) (struct rq *rq); diff --git a/kernel/sched.c b/kernel/sched.c index 41e76d325648..f47560ff3346 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1856,13 +1856,14 @@ static void update_avg(u64 *avg, u64 sample) *avg += diff >> 3; } -static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) +static void +enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, bool head) { if (wakeup) p->se.start_runtime = p->se.sum_exec_runtime; sched_info_queued(p); - p->sched_class->enqueue_task(rq, p, wakeup); + p->sched_class->enqueue_task(rq, p, wakeup, head); p->se.on_rq = 1; } @@ -1892,7 +1893,7 @@ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) if (task_contributes_to_load(p)) rq->nr_uninterruptible--; - enqueue_task(rq, p, wakeup); + enqueue_task(rq, p, wakeup, false); inc_nr_running(rq); } @@ -4236,7 +4237,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) if (running) p->sched_class->set_curr_task(rq); if (on_rq) { - enqueue_task(rq, p, 0); + enqueue_task(rq, p, 0, false); check_class_changed(rq, p, prev_class, oldprio, running); } @@ -4280,7 +4281,7 @@ void set_user_nice(struct task_struct *p, long nice) delta = p->prio - old_prio; if (on_rq) { - enqueue_task(rq, p, 0); + enqueue_task(rq, p, 0, false); /* * If the task increased its priority or is running and * lowered its priority, then reschedule its CPU: @@ -8230,7 +8231,7 @@ void sched_move_task(struct task_struct *tsk) if (unlikely(running)) tsk->sched_class->set_curr_task(rq); if (on_rq) - enqueue_task(rq, tsk, 0); + enqueue_task(rq, tsk, 0, false); task_rq_unlock(rq, &flags); } diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 22231ccb2f98..0e7a7af9cf8b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1053,7 +1053,8 @@ static inline void hrtick_update(struct rq *rq) * increased. Here we update the fair scheduling stats and * then put the task into the rbtree: */ -static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) +static void +enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup, bool head) { struct cfs_rq *cfs_rq; struct sched_entity *se = &p->se; diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 502bb614e40a..38076dabb44a 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -878,7 +878,8 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) /* * Adding/removing a task to/from a priority array: */ -static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) +static void +enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup, bool head) { struct sched_rt_entity *rt_se = &p->rt; -- cgit v1.2.3 From 37dad3fce97f01e5149d69de0833d8452c0e862e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 20 Jan 2010 20:59:01 +0000 Subject: sched: Implement head queueing for sched_rt The ability of enqueueing a task to the head of a SCHED_FIFO priority list is required to fix some violations of POSIX scheduling policy. Implement the functionality in sched_rt. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Tested-by: Carsten Emde Tested-by: Mathias Weber LKML-Reference: <20100120171629.772169931@linutronix.de> --- kernel/sched_rt.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 38076dabb44a..ca49ceb01201 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -194,7 +194,7 @@ static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) return rt_se->my_q; } -static void enqueue_rt_entity(struct sched_rt_entity *rt_se); +static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head); static void dequeue_rt_entity(struct sched_rt_entity *rt_se); static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) @@ -204,7 +204,7 @@ static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) if (rt_rq->rt_nr_running) { if (rt_se && !on_rt_rq(rt_se)) - enqueue_rt_entity(rt_se); + enqueue_rt_entity(rt_se, false); if (rt_rq->highest_prio.curr < curr->prio) resched_task(curr); } @@ -803,7 +803,7 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) dec_rt_group(rt_se, rt_rq); } -static void __enqueue_rt_entity(struct sched_rt_entity *rt_se) +static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head) { struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; @@ -819,7 +819,10 @@ static void __enqueue_rt_entity(struct sched_rt_entity *rt_se) if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) return; - list_add_tail(&rt_se->run_list, queue); + if (head) + list_add(&rt_se->run_list, queue); + else + list_add_tail(&rt_se->run_list, queue); __set_bit(rt_se_prio(rt_se), array->bitmap); inc_rt_tasks(rt_se, rt_rq); @@ -856,11 +859,11 @@ static void dequeue_rt_stack(struct sched_rt_entity *rt_se) } } -static void enqueue_rt_entity(struct sched_rt_entity *rt_se) +static void enqueue_rt_entity(struct sched_rt_entity *rt_se, bool head) { dequeue_rt_stack(rt_se); for_each_sched_rt_entity(rt_se) - __enqueue_rt_entity(rt_se); + __enqueue_rt_entity(rt_se, head); } static void dequeue_rt_entity(struct sched_rt_entity *rt_se) @@ -871,7 +874,7 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) struct rt_rq *rt_rq = group_rt_rq(rt_se); if (rt_rq && rt_rq->rt_nr_running) - __enqueue_rt_entity(rt_se); + __enqueue_rt_entity(rt_se, false); } } @@ -886,7 +889,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup, bool head) if (wakeup) rt_se->timeout = 0; - enqueue_rt_entity(rt_se); + enqueue_rt_entity(rt_se, head); if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1) enqueue_pushable_task(rq, p); -- cgit v1.2.3 From 60db48cacb9b253d5607a5ff206112a59cd09e34 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 20 Jan 2010 20:59:06 +0000 Subject: sched: Queue a deboosted task to the head of the RT prio queue rtmutex_set_prio() is used to implement priority inheritance for futexes. When a task is deboosted it gets enqueued at the tail of its RT priority list. This is violating the POSIX scheduling semantics: rt priority list X contains two runnable tasks A and B task A runs with priority X and holds mutex M task C preempts A and is blocked on mutex M -> task A is boosted to priority of task C (Y) task A unlocks the mutex M and deboosts itself -> A is dequeued from rt priority list Y -> A is enqueued to the tail of rt priority list X task C schedules away task B runs This is wrong as task A did not schedule away and therefor violates the POSIX scheduling semantics. Enqueue the task to the head of the priority list instead. Reported-by: Mathias Weber Reported-by: Carsten Emde Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Tested-by: Carsten Emde Tested-by: Mathias Weber LKML-Reference: <20100120171629.809074113@linutronix.de> --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f47560ff3346..a56ead42d651 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4237,7 +4237,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) if (running) p->sched_class->set_curr_task(rq); if (on_rq) { - enqueue_task(rq, p, 0, false); + enqueue_task(rq, p, 0, oldprio < prio); check_class_changed(rq, p, prev_class, oldprio, running); } -- cgit v1.2.3 From abd50713944c8ea9e0af5b7bffa0aacae21cc91a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 26 Jan 2010 18:50:16 +0100 Subject: perf: Reimplement frequency driven sampling There was a bug in the old period code that caused intel_pmu_enable_all() or native_write_msr_safe() to show up quite high in the profiles. In staring at that code it made my head hurt, so I rewrote it in a hopefully simpler fashion. Its now fully symetric between tick and overflow driven adjustments and uses less data to boot. The only complication is that it basically wants to do a u128 division. The code approximates that in a rather simple truncate until it fits fashion, taking care to balance the terms while truncating. This version does not generate that sampling artefact. Signed-off-by: Peter Zijlstra LKML-Reference: Cc: Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 5 +- kernel/perf_event.c | 132 +++++++++++++++++++++++++++++++-------------- 2 files changed, 94 insertions(+), 43 deletions(-) (limited to 'kernel') diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index c6f812e4d058..72b2615600d8 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -498,9 +498,8 @@ struct hw_perf_event { atomic64_t period_left; u64 interrupts; - u64 freq_count; - u64 freq_interrupts; - u64 freq_stamp; + u64 freq_time_stamp; + u64 freq_count_stamp; #endif }; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index edc46b92b508..251fb9552492 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1423,14 +1423,83 @@ void perf_event_task_sched_in(struct task_struct *task) static void perf_log_throttle(struct perf_event *event, int enable); -static void perf_adjust_period(struct perf_event *event, u64 events) +static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) +{ + u64 frequency = event->attr.sample_freq; + u64 sec = NSEC_PER_SEC; + u64 divisor, dividend; + + int count_fls, nsec_fls, frequency_fls, sec_fls; + + count_fls = fls64(count); + nsec_fls = fls64(nsec); + frequency_fls = fls64(frequency); + sec_fls = 30; + + /* + * We got @count in @nsec, with a target of sample_freq HZ + * the target period becomes: + * + * @count * 10^9 + * period = ------------------- + * @nsec * sample_freq + * + */ + + /* + * Reduce accuracy by one bit such that @a and @b converge + * to a similar magnitude. + */ +#define REDUCE_FLS(a, b) \ +do { \ + if (a##_fls > b##_fls) { \ + a >>= 1; \ + a##_fls--; \ + } else { \ + b >>= 1; \ + b##_fls--; \ + } \ +} while (0) + + /* + * Reduce accuracy until either term fits in a u64, then proceed with + * the other, so that finally we can do a u64/u64 division. + */ + while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { + REDUCE_FLS(nsec, frequency); + REDUCE_FLS(sec, count); + } + + if (count_fls + sec_fls > 64) { + divisor = nsec * frequency; + + while (count_fls + sec_fls > 64) { + REDUCE_FLS(count, sec); + divisor >>= 1; + } + + dividend = count * sec; + } else { + dividend = count * sec; + + while (nsec_fls + frequency_fls > 64) { + REDUCE_FLS(nsec, frequency); + dividend >>= 1; + } + + divisor = nsec * frequency; + } + + return div64_u64(dividend, divisor); +} + +static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) { struct hw_perf_event *hwc = &event->hw; u64 period, sample_period; s64 delta; - events *= hwc->sample_period; - period = div64_u64(events, event->attr.sample_freq); + period = perf_calculate_period(event, nsec, count); delta = (s64)(period - hwc->sample_period); delta = (delta + 7) / 8; /* low pass filter */ @@ -1441,13 +1510,22 @@ static void perf_adjust_period(struct perf_event *event, u64 events) sample_period = 1; hwc->sample_period = sample_period; + + if (atomic64_read(&hwc->period_left) > 8*sample_period) { + perf_disable(); + event->pmu->disable(event); + atomic64_set(&hwc->period_left, 0); + event->pmu->enable(event); + perf_enable(); + } } static void perf_ctx_adjust_freq(struct perf_event_context *ctx) { struct perf_event *event; struct hw_perf_event *hwc; - u64 interrupts, freq; + u64 interrupts, now; + s64 delta; raw_spin_lock(&ctx->lock); list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { @@ -1468,44 +1546,18 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx) if (interrupts == MAX_INTERRUPTS) { perf_log_throttle(event, 1); event->pmu->unthrottle(event); - interrupts = 2*sysctl_perf_event_sample_rate/HZ; } if (!event->attr.freq || !event->attr.sample_freq) continue; - /* - * if the specified freq < HZ then we need to skip ticks - */ - if (event->attr.sample_freq < HZ) { - freq = event->attr.sample_freq; - - hwc->freq_count += freq; - hwc->freq_interrupts += interrupts; - - if (hwc->freq_count < HZ) - continue; - - interrupts = hwc->freq_interrupts; - hwc->freq_interrupts = 0; - hwc->freq_count -= HZ; - } else - freq = HZ; - - perf_adjust_period(event, freq * interrupts); + event->pmu->read(event); + now = atomic64_read(&event->count); + delta = now - hwc->freq_count_stamp; + hwc->freq_count_stamp = now; - /* - * In order to avoid being stalled by an (accidental) huge - * sample period, force reset the sample period if we didn't - * get any events in this freq period. - */ - if (!interrupts) { - perf_disable(); - event->pmu->disable(event); - atomic64_set(&hwc->period_left, 0); - event->pmu->enable(event); - perf_enable(); - } + if (delta > 0) + perf_adjust_period(event, TICK_NSEC, delta); } raw_spin_unlock(&ctx->lock); } @@ -3768,12 +3820,12 @@ static int __perf_event_overflow(struct perf_event *event, int nmi, if (event->attr.freq) { u64 now = perf_clock(); - s64 delta = now - hwc->freq_stamp; + s64 delta = now - hwc->freq_time_stamp; - hwc->freq_stamp = now; + hwc->freq_time_stamp = now; - if (delta > 0 && delta < TICK_NSEC) - perf_adjust_period(event, NSEC_PER_SEC / (int)delta); + if (delta > 0 && delta < 2*TICK_NSEC) + perf_adjust_period(event, delta, hwc->last_period); } /* -- cgit v1.2.3 From ea2c68a08fedb5053ba312d661e47df9f4d72411 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Wed, 13 Jan 2010 19:38:30 +0800 Subject: tracing: Simplify test for function_graph tracing start point In the function graph tracer, a calling function is to be traced only when it is enabled through the set_graph_function file, or when it is nested in an enabled function. Current code uses TSK_TRACE_FL_GRAPH to test whether it is nested or not. Looking at the code, we can get this: (trace->depth > 0) <==> (TSK_TRACE_FL_GRAPH is set) trace->depth is more explicit to tell that it is nested. So we use trace->depth directly and simplify the code. No functionality is changed. TSK_TRACE_FL_GRAPH is not removed yet, it is left for future usage. Signed-off-by: Lai Jiangshan Cc: Ingo Molnar Cc: Steven Rostedt LKML-Reference: <4B4DB0B6.7040607@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace.h | 2 +- kernel/trace/trace_functions_graph.c | 8 ++------ 2 files changed, 3 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4df6a77eb196..ce077fbbf552 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -504,7 +504,7 @@ static inline int ftrace_graph_addr(unsigned long addr) { int i; - if (!ftrace_graph_count || test_tsk_trace_graph(current)) + if (!ftrace_graph_count) return 1; for (i = 0; i < ftrace_graph_count; i++) { diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index f2252296607c..616b135c9eb9 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -215,7 +215,8 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) if (!ftrace_trace_task(current)) return 0; - if (!ftrace_graph_addr(trace->func)) + /* trace it when it is-nested-in or is a function enabled. */ + if (!(trace->depth || ftrace_graph_addr(trace->func))) return 0; local_irq_save(flags); @@ -228,9 +229,6 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) } else { ret = 0; } - /* Only do the atomic if it is not already set */ - if (!test_tsk_trace_graph(current)) - set_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); @@ -278,8 +276,6 @@ void trace_graph_return(struct ftrace_graph_ret *trace) pc = preempt_count(); __trace_graph_return(tr, trace, flags, pc); } - if (!trace->depth) - clear_tsk_trace_graph(current); atomic_dec(&data->disabled); local_irq_restore(flags); } -- cgit v1.2.3 From 430ad5a600a83956749307b13257c464c3826b55 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 28 Jan 2010 09:32:29 +0800 Subject: perf: Factorize trace events raw sample buffer operations Introduce ftrace_perf_buf_prepare() and ftrace_perf_buf_submit() to gather the common code that operates on raw events sampling buffer. This cleans up redundant code between regular trace events, syscall events and kprobe events. Changelog v1->v2: - Rename function name as per Masami and Frederic's suggestion - Add __kprobes for ftrace_perf_buf_prepare() and make ftrace_perf_buf_submit() inline as per Masami's suggestion - Export ftrace_perf_buf_prepare since modules will use it Signed-off-by: Xiao Guangrong Acked-by: Masami Hiramatsu Cc: Ingo Molnar Cc: Steven Rostedt Cc: Paul Mackerras Cc: Jason Baron Cc: Peter Zijlstra LKML-Reference: <4B60E92D.9000808@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker --- include/linux/ftrace_event.h | 18 ++++++-- include/trace/ftrace.h | 48 +++------------------ kernel/trace/trace_event_profile.c | 52 ++++++++++++++++++++--- kernel/trace/trace_kprobe.c | 86 +++++--------------------------------- kernel/trace/trace_syscalls.c | 71 +++++-------------------------- 5 files changed, 88 insertions(+), 187 deletions(-) (limited to 'kernel') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 0a09e758c7d3..cd95919d9ff3 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -5,6 +5,7 @@ #include #include #include +#include struct trace_array; struct tracer; @@ -138,9 +139,6 @@ struct ftrace_event_call { #define FTRACE_MAX_PROFILE_SIZE 2048 -extern char *perf_trace_buf; -extern char *perf_trace_buf_nmi; - #define MAX_FILTER_PRED 32 #define MAX_FILTER_STR_VAL 256 /* Should handle KSYM_SYMBOL_LEN */ @@ -195,6 +193,20 @@ extern void ftrace_profile_disable(int event_id); extern int ftrace_profile_set_filter(struct perf_event *event, int event_id, char *filter_str); extern void ftrace_profile_free_filter(struct perf_event *event); +extern void * +ftrace_perf_buf_prepare(int size, unsigned short type, int *rctxp, + unsigned long *irq_flags); + +static inline void +ftrace_perf_buf_submit(void *raw_data, int size, int rctx, u64 addr, + u64 count, unsigned long irq_flags) +{ + struct trace_entry *entry = raw_data; + + perf_tp_event(entry->type, addr, count, raw_data, size); + perf_swevent_put_recursion_context(rctx); + local_irq_restore(irq_flags); +} #endif #endif /* _LINUX_FTRACE_EVENT_H */ diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 4a46a60c2077..f2c09e4d656c 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -850,22 +850,12 @@ ftrace_profile_templ_##call(struct ftrace_event_call *event_call, \ proto) \ { \ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ - extern int perf_swevent_get_recursion_context(void); \ - extern void perf_swevent_put_recursion_context(int rctx); \ - extern void perf_tp_event(int, u64, u64, void *, int); \ struct ftrace_raw_##call *entry; \ u64 __addr = 0, __count = 1; \ unsigned long irq_flags; \ - struct trace_entry *ent; \ int __entry_size; \ int __data_size; \ - char *trace_buf; \ - char *raw_data; \ - int __cpu; \ int rctx; \ - int pc; \ - \ - pc = preempt_count(); \ \ __data_size = ftrace_get_offsets_##call(&__data_offsets, args); \ __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\ @@ -875,42 +865,16 @@ ftrace_profile_templ_##call(struct ftrace_event_call *event_call, \ if (WARN_ONCE(__entry_size > FTRACE_MAX_PROFILE_SIZE, \ "profile buffer not large enough")) \ return; \ - \ - local_irq_save(irq_flags); \ - \ - rctx = perf_swevent_get_recursion_context(); \ - if (rctx < 0) \ - goto end_recursion; \ - \ - __cpu = smp_processor_id(); \ - \ - if (in_nmi()) \ - trace_buf = rcu_dereference(perf_trace_buf_nmi); \ - else \ - trace_buf = rcu_dereference(perf_trace_buf); \ - \ - if (!trace_buf) \ - goto end; \ - \ - raw_data = per_cpu_ptr(trace_buf, __cpu); \ - \ - *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; \ - entry = (struct ftrace_raw_##call *)raw_data; \ - ent = &entry->ent; \ - tracing_generic_entry_update(ent, irq_flags, pc); \ - ent->type = event_call->id; \ - \ + entry = (struct ftrace_raw_##call *)ftrace_perf_buf_prepare( \ + __entry_size, event_call->id, &rctx, &irq_flags); \ + if (!entry) \ + return; \ tstruct \ \ { assign; } \ \ - perf_tp_event(event_call->id, __addr, __count, entry, \ - __entry_size); \ - \ -end: \ - perf_swevent_put_recursion_context(rctx); \ -end_recursion: \ - local_irq_restore(irq_flags); \ + ftrace_perf_buf_submit(entry, __entry_size, rctx, __addr, \ + __count, irq_flags); \ } #undef DEFINE_EVENT diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c index 9e25573242cf..f0d693005075 100644 --- a/kernel/trace/trace_event_profile.c +++ b/kernel/trace/trace_event_profile.c @@ -6,14 +6,12 @@ */ #include +#include #include "trace.h" -char *perf_trace_buf; -EXPORT_SYMBOL_GPL(perf_trace_buf); - -char *perf_trace_buf_nmi; -EXPORT_SYMBOL_GPL(perf_trace_buf_nmi); +static char *perf_trace_buf; +static char *perf_trace_buf_nmi; typedef typeof(char [FTRACE_MAX_PROFILE_SIZE]) perf_trace_t ; @@ -120,3 +118,47 @@ void ftrace_profile_disable(int event_id) } mutex_unlock(&event_mutex); } + +__kprobes void *ftrace_perf_buf_prepare(int size, unsigned short type, + int *rctxp, unsigned long *irq_flags) +{ + struct trace_entry *entry; + char *trace_buf, *raw_data; + int pc, cpu; + + pc = preempt_count(); + + /* Protect the per cpu buffer, begin the rcu read side */ + local_irq_save(*irq_flags); + + *rctxp = perf_swevent_get_recursion_context(); + if (*rctxp < 0) + goto err_recursion; + + cpu = smp_processor_id(); + + if (in_nmi()) + trace_buf = rcu_dereference(perf_trace_buf_nmi); + else + trace_buf = rcu_dereference(perf_trace_buf); + + if (!trace_buf) + goto err; + + raw_data = per_cpu_ptr(trace_buf, cpu); + + /* zero the dead bytes from align to not leak stack to user */ + *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; + + entry = (struct trace_entry *)raw_data; + tracing_generic_entry_update(entry, *irq_flags, pc); + entry->type = type; + + return raw_data; +err: + perf_swevent_put_recursion_context(*rctxp); +err_recursion: + local_irq_restore(*irq_flags); + return NULL; +} +EXPORT_SYMBOL_GPL(ftrace_perf_buf_prepare); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index d6266cad6953..2e28ee36646f 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1243,14 +1243,10 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp); struct ftrace_event_call *call = &tp->call; struct kprobe_trace_entry *entry; - struct trace_entry *ent; - int size, __size, i, pc, __cpu; + int size, __size, i; unsigned long irq_flags; - char *trace_buf; - char *raw_data; int rctx; - pc = preempt_count(); __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args); size = ALIGN(__size + sizeof(u32), sizeof(u64)); size -= sizeof(u32); @@ -1258,45 +1254,16 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, "profile buffer not large enough")) return 0; - /* - * Protect the non nmi buffer - * This also protects the rcu read side - */ - local_irq_save(irq_flags); - - rctx = perf_swevent_get_recursion_context(); - if (rctx < 0) - goto end_recursion; - - __cpu = smp_processor_id(); - - if (in_nmi()) - trace_buf = rcu_dereference(perf_trace_buf_nmi); - else - trace_buf = rcu_dereference(perf_trace_buf); - - if (!trace_buf) - goto end; - - raw_data = per_cpu_ptr(trace_buf, __cpu); - - /* Zero dead bytes from alignment to avoid buffer leak to userspace */ - *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; - entry = (struct kprobe_trace_entry *)raw_data; - ent = &entry->ent; + entry = ftrace_perf_buf_prepare(size, call->id, &rctx, &irq_flags); + if (!entry) + return 0; - tracing_generic_entry_update(ent, irq_flags, pc); - ent->type = call->id; entry->nargs = tp->nr_args; entry->ip = (unsigned long)kp->addr; for (i = 0; i < tp->nr_args; i++) entry->args[i] = call_fetch(&tp->args[i].fetch, regs); - perf_tp_event(call->id, entry->ip, 1, entry, size); -end: - perf_swevent_put_recursion_context(rctx); -end_recursion: - local_irq_restore(irq_flags); + ftrace_perf_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags); return 0; } @@ -1308,14 +1275,10 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); struct ftrace_event_call *call = &tp->call; struct kretprobe_trace_entry *entry; - struct trace_entry *ent; - int size, __size, i, pc, __cpu; + int size, __size, i; unsigned long irq_flags; - char *trace_buf; - char *raw_data; int rctx; - pc = preempt_count(); __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args); size = ALIGN(__size + sizeof(u32), sizeof(u64)); size -= sizeof(u32); @@ -1323,46 +1286,17 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, "profile buffer not large enough")) return 0; - /* - * Protect the non nmi buffer - * This also protects the rcu read side - */ - local_irq_save(irq_flags); - - rctx = perf_swevent_get_recursion_context(); - if (rctx < 0) - goto end_recursion; - - __cpu = smp_processor_id(); - - if (in_nmi()) - trace_buf = rcu_dereference(perf_trace_buf_nmi); - else - trace_buf = rcu_dereference(perf_trace_buf); - - if (!trace_buf) - goto end; - - raw_data = per_cpu_ptr(trace_buf, __cpu); - - /* Zero dead bytes from alignment to avoid buffer leak to userspace */ - *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; - entry = (struct kretprobe_trace_entry *)raw_data; - ent = &entry->ent; + entry = ftrace_perf_buf_prepare(size, call->id, &rctx, &irq_flags); + if (!entry) + return 0; - tracing_generic_entry_update(ent, irq_flags, pc); - ent->type = call->id; entry->nargs = tp->nr_args; entry->func = (unsigned long)tp->rp.kp.addr; entry->ret_ip = (unsigned long)ri->ret_addr; for (i = 0; i < tp->nr_args; i++) entry->args[i] = call_fetch(&tp->args[i].fetch, regs); - perf_tp_event(call->id, entry->ret_ip, 1, entry, size); -end: - perf_swevent_put_recursion_context(rctx); -end_recursion: - local_irq_restore(irq_flags); + ftrace_perf_buf_submit(entry, size, rctx, entry->ret_ip, 1, irq_flags); return 0; } diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index f694f66d75b0..4e332b9e449c 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -433,12 +433,9 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) struct syscall_metadata *sys_data; struct syscall_trace_enter *rec; unsigned long flags; - char *trace_buf; - char *raw_data; int syscall_nr; int rctx; int size; - int cpu; syscall_nr = syscall_get_nr(current, regs); if (!test_bit(syscall_nr, enabled_prof_enter_syscalls)) @@ -457,37 +454,15 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) "profile buffer not large enough")) return; - /* Protect the per cpu buffer, begin the rcu read side */ - local_irq_save(flags); - - rctx = perf_swevent_get_recursion_context(); - if (rctx < 0) - goto end_recursion; - - cpu = smp_processor_id(); - - trace_buf = rcu_dereference(perf_trace_buf); - - if (!trace_buf) - goto end; - - raw_data = per_cpu_ptr(trace_buf, cpu); - - /* zero the dead bytes from align to not leak stack to user */ - *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; + rec = (struct syscall_trace_enter *)ftrace_perf_buf_prepare(size, + sys_data->enter_event->id, &rctx, &flags); + if (!rec) + return; - rec = (struct syscall_trace_enter *) raw_data; - tracing_generic_entry_update(&rec->ent, 0, 0); - rec->ent.type = sys_data->enter_event->id; rec->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, (unsigned long *)&rec->args); - perf_tp_event(sys_data->enter_event->id, 0, 1, rec, size); - -end: - perf_swevent_put_recursion_context(rctx); -end_recursion: - local_irq_restore(flags); + ftrace_perf_buf_submit(rec, size, rctx, 0, 1, flags); } int prof_sysenter_enable(struct ftrace_event_call *call) @@ -531,11 +506,8 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) struct syscall_trace_exit *rec; unsigned long flags; int syscall_nr; - char *trace_buf; - char *raw_data; int rctx; int size; - int cpu; syscall_nr = syscall_get_nr(current, regs); if (!test_bit(syscall_nr, enabled_prof_exit_syscalls)) @@ -557,38 +529,15 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) "exit event has grown above profile buffer size")) return; - /* Protect the per cpu buffer, begin the rcu read side */ - local_irq_save(flags); - - rctx = perf_swevent_get_recursion_context(); - if (rctx < 0) - goto end_recursion; - - cpu = smp_processor_id(); - - trace_buf = rcu_dereference(perf_trace_buf); - - if (!trace_buf) - goto end; - - raw_data = per_cpu_ptr(trace_buf, cpu); - - /* zero the dead bytes from align to not leak stack to user */ - *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL; - - rec = (struct syscall_trace_exit *)raw_data; + rec = (struct syscall_trace_exit *)ftrace_perf_buf_prepare(size, + sys_data->exit_event->id, &rctx, &flags); + if (!rec) + return; - tracing_generic_entry_update(&rec->ent, 0, 0); - rec->ent.type = sys_data->exit_event->id; rec->nr = syscall_nr; rec->ret = syscall_get_return_value(current, regs); - perf_tp_event(sys_data->exit_event->id, 0, 1, rec, size); - -end: - perf_swevent_put_recursion_context(rctx); -end_recursion: - local_irq_restore(flags); + ftrace_perf_buf_submit(rec, size, rctx, 0, 1, flags); } int prof_sysexit_enable(struct ftrace_event_call *call) -- cgit v1.2.3 From 1e12a4a7a3a78bc9c3aaf3486dde3b8ab1cdf465 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong Date: Thu, 28 Jan 2010 09:34:27 +0800 Subject: tracing/kprobe: Cleanup unused return value of tracing functions The return values of the kprobe's tracing functions are meaningless, lets remove these. Signed-off-by: Xiao Guangrong Acked-by: Masami Hiramatsu Cc: Steven Rostedt Cc: Ingo Molnar Cc: Paul Mackerras Cc: Jason Baron Cc: Peter Zijlstra LKML-Reference: <4B60E9A3.2040505@cn.fujitsu.com> [fweisbec@gmail: whitespace fixes, drop useless void returns in end of functions] Signed-off-by: Frederic Weisbecker --- kernel/trace/trace_kprobe.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 2e28ee36646f..6178abf3637e 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -942,7 +942,7 @@ static const struct file_operations kprobe_profile_ops = { }; /* Kprobe handler */ -static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) +static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) { struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp); struct kprobe_trace_entry *entry; @@ -962,7 +962,7 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) event = trace_current_buffer_lock_reserve(&buffer, call->id, size, irq_flags, pc); if (!event) - return 0; + return; entry = ring_buffer_event_data(event); entry->nargs = tp->nr_args; @@ -972,11 +972,10 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) if (!filter_current_check_discard(buffer, call, entry, event)) trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc); - return 0; } /* Kretprobe handler */ -static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri, +static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri, struct pt_regs *regs) { struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); @@ -995,7 +994,7 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri, event = trace_current_buffer_lock_reserve(&buffer, call->id, size, irq_flags, pc); if (!event) - return 0; + return; entry = ring_buffer_event_data(event); entry->nargs = tp->nr_args; @@ -1006,8 +1005,6 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri, if (!filter_current_check_discard(buffer, call, entry, event)) trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc); - - return 0; } /* Event entry printers */ @@ -1237,7 +1234,7 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, #ifdef CONFIG_PERF_EVENTS /* Kprobe profile handler */ -static __kprobes int kprobe_profile_func(struct kprobe *kp, +static __kprobes void kprobe_profile_func(struct kprobe *kp, struct pt_regs *regs) { struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp); @@ -1252,11 +1249,11 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, size -= sizeof(u32); if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE, "profile buffer not large enough")) - return 0; + return; entry = ftrace_perf_buf_prepare(size, call->id, &rctx, &irq_flags); if (!entry) - return 0; + return; entry->nargs = tp->nr_args; entry->ip = (unsigned long)kp->addr; @@ -1264,12 +1261,10 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, entry->args[i] = call_fetch(&tp->args[i].fetch, regs); ftrace_perf_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags); - - return 0; } /* Kretprobe profile handler */ -static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, +static __kprobes void kretprobe_profile_func(struct kretprobe_instance *ri, struct pt_regs *regs) { struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp); @@ -1284,11 +1279,11 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, size -= sizeof(u32); if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE, "profile buffer not large enough")) - return 0; + return; entry = ftrace_perf_buf_prepare(size, call->id, &rctx, &irq_flags); if (!entry) - return 0; + return; entry->nargs = tp->nr_args; entry->func = (unsigned long)tp->rp.kp.addr; @@ -1297,8 +1292,6 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, entry->args[i] = call_fetch(&tp->args[i].fetch, regs); ftrace_perf_buf_submit(entry, size, rctx, entry->ret_ip, 1, irq_flags); - - return 0; } static int probe_profile_enable(struct ftrace_event_call *call) -- cgit v1.2.3 From 75c9f3284a7ff957829f44baace82406a6354ceb Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 29 Jan 2010 09:04:26 +0100 Subject: perf_events: Fix sample_period transfer on inherit One problem with frequency driven counters is that we cannot predict the rate at which they trigger, therefore we have to start them at period=1, this causes a ramp up effect. However, if we fail to propagate the stable state on fork each new child will have to ramp up again. This can lead to significant artifacts in sample data. Signed-off-by: Peter Zijlstra Cc: eranian@google.com Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: <1264752266.4283.2121.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 251fb9552492..53dc2a362111 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -5002,8 +5002,15 @@ inherit_event(struct perf_event *parent_event, else child_event->state = PERF_EVENT_STATE_OFF; - if (parent_event->attr.freq) - child_event->hw.sample_period = parent_event->hw.sample_period; + if (parent_event->attr.freq) { + u64 sample_period = parent_event->hw.sample_period; + struct hw_perf_event *hwc = &child_event->hw; + + hwc->sample_period = sample_period; + hwc->last_period = sample_period; + + atomic64_set(&hwc->period_left, sample_period); + } child_event->overflow_handler = parent_event->overflow_handler; -- cgit v1.2.3 From 61ef2489dbf587258526cfd4ebf4bba3b079f401 Mon Sep 17 00:00:00 2001 From: Wu Fengguang Date: Fri, 22 Jan 2010 16:16:19 +0800 Subject: resources: introduce generic page_is_ram() It's based on walk_system_ram_range(), for archs that don't have their own page_is_ram(). The static verions in MIPS and SCORE are also made global. v4: prefer plain 1 instead of PAGE_IS_RAM (H. Peter Anvin) v3: add comment (KAMEZAWA Hiroyuki) "AFAIK, this "System RAM" information has been used for kdump to grab valid memory area and seems good for the kernel itself." v2: add PAGE_IS_RAM macro (Américo Wang) Cc: Chen Liqin Cc: Lennox Wu Cc: Américo Wang Cc: linux-mips@linux-mips.org Cc: Yinghai Lu Acked-by: Ralf Baechle Reviewed-by: KAMEZAWA Hiroyuki Signed-off-by: Wu Fengguang LKML-Reference: <20100122081619.GA6431@localhost> Cc: Andrew Morton Signed-off-by: H. Peter Anvin --- arch/mips/mm/init.c | 2 +- arch/score/mm/init.c | 2 +- include/linux/ioport.h | 2 ++ kernel/resource.c | 13 +++++++++++++ 4 files changed, 17 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 15aa1902a788..4d72aabe8352 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -294,7 +294,7 @@ void __init fixrange_init(unsigned long start, unsigned long end, } #ifndef CONFIG_NEED_MULTIPLE_NODES -static int __init page_is_ram(unsigned long pagenr) +int page_is_ram(unsigned long pagenr) { int i; diff --git a/arch/score/mm/init.c b/arch/score/mm/init.c index 4e3dcd0c4716..f684a590c21d 100644 --- a/arch/score/mm/init.c +++ b/arch/score/mm/init.c @@ -59,7 +59,7 @@ static unsigned long setup_zero_page(void) } #ifndef CONFIG_NEED_MULTIPLE_NODES -static int __init page_is_ram(unsigned long pagenr) +int page_is_ram(unsigned long pagenr) { if (pagenr >= min_low_pfn && pagenr < max_low_pfn) return 1; diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 83aa81297ea3..11ef7952b63a 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -188,5 +188,7 @@ extern int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)); +extern int page_is_ram(unsigned long pfn); + #endif /* __ASSEMBLY__ */ #endif /* _LINUX_IOPORT_H */ diff --git a/kernel/resource.c b/kernel/resource.c index fb11a58b9594..b4d637a55256 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -297,6 +297,19 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, #endif +static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg) +{ + return 1; +} +/* + * This generic page_is_ram() returns true if specified address is + * registered as "System RAM" in iomem_resource list. + */ +int __attribute__((weak)) page_is_ram(unsigned long pfn) +{ + return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1; +} + /* * Find empty slot in the resource tree given range and alignment. */ -- cgit v1.2.3 From e52730071567ec5b6f57e21d6693b112e01e1d0e Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 26 Jan 2010 16:31:19 -0800 Subject: Generic page_is_ram: use __weak Use __weak instead of __attribute__((weak)). Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: H. Peter Anvin --- kernel/resource.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/resource.c b/kernel/resource.c index b4d637a55256..e68cd7477c40 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -305,7 +305,7 @@ static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg) * This generic page_is_ram() returns true if specified address is * registered as "System RAM" in iomem_resource list. */ -int __attribute__((weak)) page_is_ram(unsigned long pfn) +int __weak page_is_ram(unsigned long pfn) { return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1; } -- cgit v1.2.3 From 90fdbdb48442a03c72cae5463e6edb64cb3a3a7d Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Sun, 31 Jan 2010 20:53:24 +0900 Subject: sched: Use for_each_bit No change in functionality. Signed-off-by: Akinobu Mita Cc: Peter Zijlstra Cc: Andrew Morton LKML-Reference: <1264938810-4173-1-git-send-email-akinobu.mita@gmail.com> Signed-off-by: Ingo Molnar --- kernel/sched_cpupri.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_cpupri.c b/kernel/sched_cpupri.c index 597b33099dfa..eeb3506c4834 100644 --- a/kernel/sched_cpupri.c +++ b/kernel/sched_cpupri.c @@ -47,9 +47,7 @@ static int convert_prio(int prio) } #define for_each_cpupri_active(array, idx) \ - for (idx = find_first_bit(array, CPUPRI_NR_PRIORITIES); \ - idx < CPUPRI_NR_PRIORITIES; \ - idx = find_next_bit(array, CPUPRI_NR_PRIORITIES, idx+1)) + for_each_bit(idx, array, CPUPRI_NR_PRIORITIES) /** * cpupri_find - find the best (lowest-pri) CPU in the system -- cgit v1.2.3 From 4a461c85b643258e305eb5a3aced34009db2f818 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 1 Feb 2010 11:13:39 +0100 Subject: sched: Remove unused update_shares_locked() Commit f492e12ef050e02bf0185b6b57874992591b9be1 ("sched: Remove load_balance_newidle()") removed the only user of this function, so remove it too. Reported-by: Stephen Rothwell Signed-off-by: Peter Zijlstra LKML-Reference: <1265019219.24455.128.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index a56ead42d651..2386f5440002 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1633,16 +1633,6 @@ static void update_shares(struct sched_domain *sd) } } -static void update_shares_locked(struct rq *rq, struct sched_domain *sd) -{ - if (root_task_group_empty()) - return; - - raw_spin_unlock(&rq->lock); - update_shares(sd); - raw_spin_lock(&rq->lock); -} - static void update_h_load(long cpu) { if (root_task_group_empty()) @@ -1657,10 +1647,6 @@ static inline void update_shares(struct sched_domain *sd) { } -static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd) -{ -} - #endif #ifdef CONFIG_PREEMPT -- cgit v1.2.3 From 615d0ebbc782b67296e3226c293f520f93f93515 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 2 Feb 2010 16:49:04 -0500 Subject: kprobes: Disable booster when CONFIG_PREEMPT=y Disable kprobe booster when CONFIG_PREEMPT=y at this time, because it can't ensure that all kernel threads preempted on kprobe's boosted slot run out from the slot even using freeze_processes(). The booster on preemptive kernel will be resumed if synchronize_tasks() or something like that is introduced. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Ananth N Mavinakayanahalli Cc: Frederic Weisbecker Cc: Jim Keniston Cc: Mathieu Desnoyers Cc: Steven Rostedt LKML-Reference: <20100202214904.4694.24330.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- arch/ia64/kernel/kprobes.c | 2 +- arch/x86/kernel/kprobes.c | 2 +- kernel/kprobes.c | 29 ++--------------------------- 3 files changed, 4 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 9adac441ac9b..7026b29e277a 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -870,7 +870,7 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) return 1; ss_probe: -#if !defined(CONFIG_PREEMPT) || defined(CONFIG_FREEZER) +#if !defined(CONFIG_PREEMPT) if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) { /* Boost up -- we can execute copied instructions directly */ ia64_psr(regs)->ri = p->ainsn.slot; diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 5b8c7505b3bc..9453815138fa 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -429,7 +429,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { -#if !defined(CONFIG_PREEMPT) || defined(CONFIG_FREEZER) +#if !defined(CONFIG_PREEMPT) if (p->ainsn.boostable == 1 && !p->post_handler) { /* Boost up -- we can execute copied instructions directly */ reset_current_kprobe(); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b7df302a0204..9907a03c29f6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -124,30 +124,6 @@ static LIST_HEAD(kprobe_insn_pages); static int kprobe_garbage_slots; static int collect_garbage_slots(void); -static int __kprobes check_safety(void) -{ - int ret = 0; -#if defined(CONFIG_PREEMPT) && defined(CONFIG_FREEZER) - ret = freeze_processes(); - if (ret == 0) { - struct task_struct *p, *q; - do_each_thread(p, q) { - if (p != current && p->state == TASK_RUNNING && - p->pid != 0) { - printk("Check failed: %s is running\n",p->comm); - ret = -1; - goto loop_end; - } - } while_each_thread(p, q); - } -loop_end: - thaw_processes(); -#else - synchronize_sched(); -#endif - return ret; -} - /** * __get_insn_slot() - Find a slot on an executable page for an instruction. * We allocate an executable page if there's no room on existing ones. @@ -235,9 +211,8 @@ static int __kprobes collect_garbage_slots(void) { struct kprobe_insn_page *kip, *next; - /* Ensure no-one is preepmted on the garbages */ - if (check_safety()) - return -EAGAIN; + /* Ensure no-one is interrupted on the garbages */ + synchronize_sched(); list_for_each_entry_safe(kip, next, &kprobe_insn_pages, list) { int i; -- cgit v1.2.3 From 2cfa19780d61740f65790c5bae363b759d7c96fa Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 2 Feb 2010 16:49:11 -0500 Subject: ftrace/alternatives: Introducing *_text_reserved functions Introducing *_text_reserved functions for checking the text address range is partially reserved or not. This patch provides checking routines for x86 smp alternatives and dynamic ftrace. Since both functions modify fixed pieces of kernel text, they should reserve and protect those from other dynamic text modifier, like kprobes. This will also be extended when introducing other subsystems which modify fixed pieces of kernel text. Dynamic text modifiers should avoid those. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Steven Rostedt Cc: przemyslaw@pawelczyk.it Cc: Frederic Weisbecker Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Mathieu Desnoyers Cc: Jason Baron LKML-Reference: <20100202214911.4694.16587.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/alternative.h | 5 +++++ arch/x86/kernel/alternative.c | 16 ++++++++++++++++ include/linux/ftrace.h | 6 ++++++ kernel/trace/ftrace.c | 15 +++++++++++++++ 4 files changed, 42 insertions(+) (limited to 'kernel') diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 69b74a7b877f..ac80b7d70014 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -65,12 +65,17 @@ extern void alternatives_smp_module_add(struct module *mod, char *name, void *text, void *text_end); extern void alternatives_smp_module_del(struct module *mod); extern void alternatives_smp_switch(int smp); +extern int alternatives_text_reserved(void *start, void *end); #else static inline void alternatives_smp_module_add(struct module *mod, char *name, void *locks, void *locks_end, void *text, void *text_end) {} static inline void alternatives_smp_module_del(struct module *mod) {} static inline void alternatives_smp_switch(int smp) {} +static inline int alternatives_text_reserved(void *start, void *end) +{ + return 0; +} #endif /* CONFIG_SMP */ /* alternative assembly primitive: */ diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index de7353c0ce9c..3c13284ff86d 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -390,6 +390,22 @@ void alternatives_smp_switch(int smp) mutex_unlock(&smp_alt); } +/* Return 1 if the address range is reserved for smp-alternatives */ +int alternatives_text_reserved(void *start, void *end) +{ + struct smp_alt_module *mod; + u8 **ptr; + + list_for_each_entry(mod, &smp_alt_modules, next) { + if (mod->text > end || mod->text_end < start) + continue; + for (ptr = mod->locks; ptr < mod->locks_end; ptr++) + if (start <= *ptr && end >= *ptr) + return 1; + } + + return 0; +} #endif #ifdef CONFIG_PARAVIRT diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 0b4f97d24d7f..9d127efed43c 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -134,6 +134,8 @@ extern void unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops); extern void unregister_ftrace_function_probe_all(char *glob); +extern int ftrace_text_reserved(void *start, void *end); + enum { FTRACE_FL_FREE = (1 << 0), FTRACE_FL_FAILED = (1 << 1), @@ -250,6 +252,10 @@ static inline int unregister_ftrace_command(char *cmd_name) { return -EINVAL; } +static inline int ftrace_text_reserved(void *start, void *end) +{ + return 0; +} #endif /* CONFIG_DYNAMIC_FTRACE */ /* totally disable ftrace - can not re-enable after this */ diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1e6640f80454..3d90661a5f40 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1025,6 +1025,21 @@ static void ftrace_bug(int failed, unsigned long ip) } +/* Return 1 if the address range is reserved for ftrace */ +int ftrace_text_reserved(void *start, void *end) +{ + struct dyn_ftrace *rec; + struct ftrace_page *pg; + + do_for_each_ftrace_rec(pg, rec) { + if (rec->ip <= (unsigned long)end && + rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start) + return 1; + } while_for_each_ftrace_rec(); + return 0; +} + + static int __ftrace_replace_code(struct dyn_ftrace *rec, int enable) { -- cgit v1.2.3 From 4554dbcb85a4ed2abaa2b6fa15649b796699ec89 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 2 Feb 2010 16:49:18 -0500 Subject: kprobes: Check probe address is reserved Check whether the address of new probe is already reserved by ftrace or alternatives (on x86) when registering new probe. If reserved, it returns an error and not register the probe. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Steven Rostedt Cc: przemyslaw@pawelczyk.it Cc: Frederic Weisbecker Cc: Ananth N Mavinakayanahalli Cc: Jim Keniston Cc: Mathieu Desnoyers Cc: Jason Baron LKML-Reference: <20100202214918.4694.94179.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/kprobes.c | 3 +++ kernel/kprobes.c | 4 +++- 2 files changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 9453815138fa..5de9f4a9c3fd 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -337,6 +337,9 @@ static void __kprobes arch_copy_kprobe(struct kprobe *p) int __kprobes arch_prepare_kprobe(struct kprobe *p) { + if (alternatives_text_reserved(p->addr, p->addr)) + return -EINVAL; + if (!can_probe((unsigned long)p->addr)) return -EILSEQ; /* insn: must be on special executable page on x86. */ diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9907a03c29f6..c3340e836c37 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -44,6 +44,7 @@ #include #include #include +#include #include #include @@ -703,7 +704,8 @@ int __kprobes register_kprobe(struct kprobe *p) preempt_disable(); if (!kernel_text_address((unsigned long) p->addr) || - in_kprobes_functions((unsigned long) p->addr)) { + in_kprobes_functions((unsigned long) p->addr) || + ftrace_text_reserved(p->addr, p->addr)) { preempt_enable(); return -EINVAL; } -- cgit v1.2.3 From f24bb999d2b9f2950e5cac5b69bffedf73c24ea4 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 2 Feb 2010 16:49:25 -0500 Subject: ftrace: Remove record freezing Remove record freezing. Because kprobes never puts probe on ftrace's mcount call anymore, it doesn't need ftrace to check whether kprobes on it. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Steven Rostedt Cc: przemyslaw@pawelczyk.it Cc: Frederic Weisbecker LKML-Reference: <20100202214925.4694.73469.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- include/linux/ftrace.h | 1 - kernel/trace/ftrace.c | 39 --------------------------------------- 2 files changed, 40 deletions(-) (limited to 'kernel') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 9d127efed43c..eb054ae95605 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -143,7 +143,6 @@ enum { FTRACE_FL_ENABLED = (1 << 3), FTRACE_FL_NOTRACE = (1 << 4), FTRACE_FL_CONVERTED = (1 << 5), - FTRACE_FL_FROZEN = (1 << 6), }; struct dyn_ftrace { diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3d90661a5f40..1904797f4a8a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -22,7 +22,6 @@ #include #include #include -#include #include #include #include @@ -898,36 +897,6 @@ static struct dyn_ftrace *ftrace_free_records; } \ } -#ifdef CONFIG_KPROBES - -static int frozen_record_count; - -static inline void freeze_record(struct dyn_ftrace *rec) -{ - if (!(rec->flags & FTRACE_FL_FROZEN)) { - rec->flags |= FTRACE_FL_FROZEN; - frozen_record_count++; - } -} - -static inline void unfreeze_record(struct dyn_ftrace *rec) -{ - if (rec->flags & FTRACE_FL_FROZEN) { - rec->flags &= ~FTRACE_FL_FROZEN; - frozen_record_count--; - } -} - -static inline int record_frozen(struct dyn_ftrace *rec) -{ - return rec->flags & FTRACE_FL_FROZEN; -} -#else -# define freeze_record(rec) ({ 0; }) -# define unfreeze_record(rec) ({ 0; }) -# define record_frozen(rec) ({ 0; }) -#endif /* CONFIG_KPROBES */ - static void ftrace_free_rec(struct dyn_ftrace *rec) { rec->freelist = ftrace_free_records; @@ -1091,14 +1060,6 @@ static void ftrace_replace_code(int enable) !(rec->flags & FTRACE_FL_CONVERTED)) continue; - /* ignore updates to this record's mcount site */ - if (get_kprobe((void *)rec->ip)) { - freeze_record(rec); - continue; - } else { - unfreeze_record(rec); - } - failed = __ftrace_replace_code(rec, enable); if (failed) { rec->flags |= FTRACE_FL_FAILED; -- cgit v1.2.3 From 74b7eb5885415ed41d012f432398d1b697115b5f Mon Sep 17 00:00:00 2001 From: Yong Zhang Date: Fri, 29 Jan 2010 14:57:52 +0800 Subject: sched: Change usage of rt_rq->rt_se to rt_rq->tg->rt_se[cpu] This is the first step to remove rt_rq member rt_se because it have the same meaning with tg->rt_se[cpu]. And the latter style is also used by the fair scheduling class. Signed-off-by: Yong Zhang Cc: Rusty Russell Signed-off-by: Peter Zijlstra LKML-Reference: <2674af741001282257r28c97a92o9f90cf16fe8d3d84@mail.gmail.com> Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index ca49ceb01201..bf3e38fdbe6d 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -199,8 +199,11 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se); static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) { + int this_cpu = smp_processor_id(); struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr; - struct sched_rt_entity *rt_se = rt_rq->rt_se; + struct sched_rt_entity *rt_se; + + rt_se = rt_rq->tg->rt_se[this_cpu]; if (rt_rq->rt_nr_running) { if (rt_se && !on_rt_rq(rt_se)) @@ -212,7 +215,10 @@ static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) static void sched_rt_rq_dequeue(struct rt_rq *rt_rq) { - struct sched_rt_entity *rt_se = rt_rq->rt_se; + int this_cpu = smp_processor_id(); + struct sched_rt_entity *rt_se; + + rt_se = rt_rq->tg->rt_se[this_cpu]; if (rt_se && on_rt_rq(rt_se)) dequeue_rt_entity(rt_se); -- cgit v1.2.3 From 23577256953c870de9b724c3a2611ce7be6a1e4e Mon Sep 17 00:00:00 2001 From: Yong Zhang Date: Fri, 29 Jan 2010 14:58:47 +0800 Subject: sched: Remove member rt_se from struct rt_rq It's a duplicate of tg->rt_se[cpu] and the only usage is sched_rt_rq_dequeue() and sched_rt_rq_enqueue(). After the first patch to those two function. rt_se can be removed. Signed-off-by: Yong Zhang Cc: Rusty Russell Signed-off-by: Peter Zijlstra LKML-Reference: <2674af741001282258q38781619u653ca4a7dd267347@mail.gmail.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 2386f5440002..6cee227b1459 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -436,7 +436,6 @@ struct rt_rq { struct rq *rq; struct list_head leaf_rt_rq_list; struct task_group *tg; - struct sched_rt_entity *rt_se; #endif }; @@ -7592,7 +7591,6 @@ static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, tg->rt_rq[cpu] = rt_rq; init_rt_rq(rt_rq, rq); rt_rq->tg = tg; - rt_rq->rt_se = rt_se; rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime; if (add) list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); -- cgit v1.2.3 From 9717e6cd3db22eade7dbae0fc9235c66325a7132 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 28 Jan 2010 13:57:44 +0100 Subject: perf_events: Optimize perf_event_task_tick() Pretty much all of the calls do perf_disable/perf_enable cycles, pull that out to cut back on hardware programming. Signed-off-by: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 40f8b07c5601..087025fe3ba1 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1573,12 +1573,8 @@ static void rotate_ctx(struct perf_event_context *ctx) raw_spin_lock(&ctx->lock); /* Rotate the first entry last of non-pinned groups */ - perf_disable(); - list_rotate_left(&ctx->flexible_groups); - perf_enable(); - raw_spin_unlock(&ctx->lock); } @@ -1593,6 +1589,8 @@ void perf_event_task_tick(struct task_struct *curr) cpuctx = &__get_cpu_var(perf_cpu_context); ctx = curr->perf_event_ctxp; + perf_disable(); + perf_ctx_adjust_freq(&cpuctx->ctx); if (ctx) perf_ctx_adjust_freq(ctx); @@ -1608,6 +1606,8 @@ void perf_event_task_tick(struct task_struct *curr) cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); if (ctx) task_ctx_sched_in(curr, EVENT_FLEXIBLE); + + perf_enable(); } static int event_enable_on_exec(struct perf_event *event, -- cgit v1.2.3 From 5ecaafdbf44b1ba400b746c60c401d54c7ee0863 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Fri, 5 Feb 2010 01:24:34 -0500 Subject: kprobes: Add mcount to the kprobes blacklist Since mcount function can be called from everywhere, it should be blacklisted. Moreover, the "mcount" symbol is a special symbol name. So, it is better to put it in the generic blacklist. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Ananth N Mavinakayanahalli Cc: Steven Rostedt LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- kernel/kprobes.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index c3340e836c37..ccec774c716d 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -94,6 +94,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = { {"native_get_debugreg",}, {"irq_entries_start",}, {"common_interrupt",}, + {"mcount",}, /* mcount can be called from everywhere */ {NULL} /* Terminator */ }; -- cgit v1.2.3 From 50200df462023b187d80a99a52f5f2cfe3c86c26 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Tue, 2 Feb 2010 14:46:13 -0800 Subject: kernel/sched.c: Suppress unused var warning On UP: kernel/sched.c: In function 'wake_up_new_task': kernel/sched.c:2631: warning: unused variable 'cpu' Signed-off-by: Andrew Morton Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 3a8fb30a91b1..e3199df426e3 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2647,7 +2647,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) { unsigned long flags; struct rq *rq; - int cpu = get_cpu(); + int cpu __maybe_unused = get_cpu(); #ifdef CONFIG_SMP /* -- cgit v1.2.3 From fa535a77bd3fa32b9215ba375d6a202fe73e1dd6 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Tue, 2 Feb 2010 14:46:13 -0800 Subject: sched: cpuacct: Use bigger percpu counter batch values for stats counters When CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_CGROUP_CPUACCT are enabled we can call cpuacct_update_stats with values much larger than percpu_counter_batch. This means the call to percpu_counter_add will always add to the global count which is protected by a spinlock and we end up with a global spinlock in the scheduler. Based on an idea by KOSAKI Motohiro, this patch scales the batch value by cputime_one_jiffy such that we have the same batch limit as we would if CONFIG_VIRT_CPU_ACCOUNTING was disabled. His patch did this once at boot but that initialisation happened too early on PowerPC (before time_init) and it was never updated at runtime as a result of a hotplug cpu add/remove. This patch instead scales percpu_counter_batch by cputime_one_jiffy at runtime, which keeps the batch correct even after cpu hotplug operations. We cap it at INT_MAX in case of overflow. For architectures that do not support CONFIG_VIRT_CPU_ACCOUNTING, cputime_one_jiffy is the constant 1 and gcc is smart enough to optimise min(s32 percpu_counter_batch, INT_MAX) to just percpu_counter_batch at least on x86 and PowerPC. So there is no need to add an #ifdef. On a 64 thread PowerPC box with CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_CGROUP_CPUACCT enabled, a context switch microbenchmark is 234x faster and almost matches a CONFIG_CGROUP_CPUACCT disabled kernel: CONFIG_CGROUP_CPUACCT disabled: 16906698 ctx switches/sec CONFIG_CGROUP_CPUACCT enabled: 61720 ctx switches/sec CONFIG_CGROUP_CPUACCT + patch: 16663217 ctx switches/sec Tested with: wget http://ozlabs.org/~anton/junkcode/context_switch.c make context_switch for i in `seq 0 63`; do taskset -c $i ./context_switch & done vmstat 1 Signed-off-by: Anton Blanchard Reviewed-by: KOSAKI Motohiro Acked-by: Balbir Singh Tested-by: Balbir Singh Cc: Peter Zijlstra Cc: Martin Schwidefsky Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- kernel/sched.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index f96be9370b75..bae6fcfe6d75 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8997,6 +8997,23 @@ static void cpuacct_charge(struct task_struct *tsk, u64 cputime) rcu_read_unlock(); } +/* + * When CONFIG_VIRT_CPU_ACCOUNTING is enabled one jiffy can be very large + * in cputime_t units. As a result, cpuacct_update_stats calls + * percpu_counter_add with values large enough to always overflow the + * per cpu batch limit causing bad SMP scalability. + * + * To fix this we scale percpu_counter_batch by cputime_one_jiffy so we + * batch the same amount of time with CONFIG_VIRT_CPU_ACCOUNTING disabled + * and enabled. We cap it at INT_MAX which is the largest allowed batch value. + */ +#ifdef CONFIG_SMP +#define CPUACCT_BATCH \ + min_t(long, percpu_counter_batch * cputime_one_jiffy, INT_MAX) +#else +#define CPUACCT_BATCH 0 +#endif + /* * Charge the system/user time to the task's accounting group. */ @@ -9004,6 +9021,7 @@ static void cpuacct_update_stats(struct task_struct *tsk, enum cpuacct_stat_index idx, cputime_t val) { struct cpuacct *ca; + int batch = CPUACCT_BATCH; if (unlikely(!cpuacct_subsys.active)) return; @@ -9012,7 +9030,7 @@ static void cpuacct_update_stats(struct task_struct *tsk, ca = task_ca(tsk); do { - percpu_counter_add(&ca->cpustat[idx], val); + __percpu_counter_add(&ca->cpustat[idx], val, batch); ca = ca->parent; } while (ca); rcu_read_unlock(); -- cgit v1.2.3 From 301ba0457f1ed853fc08e57785f8c87fe7e49c68 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Tue, 9 Feb 2010 15:07:40 +1100 Subject: kthread, sched: Remove reference to kthread_create_on_cpu kthread_create_on_cpu doesn't exist so update a comment in kthread.c to reflect this. Signed-off-by: Anton Blanchard Acked-by: Rusty Russell Cc: Peter Zijlstra LKML-Reference: <20100209040740.GB3702@kryten> Signed-off-by: Ingo Molnar --- kernel/kthread.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kthread.c b/kernel/kthread.c index fbb6222fe7e0..82ed0ea15194 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -101,7 +101,7 @@ static void create_kthread(struct kthread_create_info *create) * * Description: This helper function creates and names a kernel * thread. The thread will be stopped: use wake_up_process() to start - * it. See also kthread_run(), kthread_create_on_cpu(). + * it. See also kthread_run(). * * When woken, the thread will run @threadfn() with @data as its * argument. @threadfn() can either call do_exit() directly if it is a -- cgit v1.2.3 From ede55c9d78101fef0d8e620940a5163f14b02f29 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 27 Jan 2010 11:25:54 -0500 Subject: tracing: Add correct/incorrect to sort keys for branch annotation output The branch annotation is a bit difficult to see the worst offenders because it only sorts by percentage: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 0 163 100 qdisc_restart sch_generic.c 179 0 163 100 pfifo_fast_dequeue sch_generic.c 447 0 4 100 pskb_trim_rcsum skbuff.h 1689 0 4 100 llc_rcv llc_input.c 170 0 18 100 psmouse_interrupt psmouse-base.c 304 0 3 100 atkbd_interrupt atkbd.c 389 0 5 100 usb_alloc_dev usb.c 437 0 11 100 vsscanf vsprintf.c 1897 0 2 100 IS_ERR err.h 34 0 23 100 __rmqueue_fallback page_alloc.c 865 0 4 100 probe_wakeup_sched_switch trace_sched_wakeup.c 142 0 3 100 move_masked_irq migration.c 11 Adding the incorrect and correct values as sort keys makes this file a bit more informative: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 0 366541 100 audit_syscall_entry auditsc.c 1637 0 366538 100 audit_syscall_exit auditsc.c 1685 0 115839 100 sched_info_switch sched_stats.h 269 0 74567 100 sched_info_queued sched_stats.h 222 0 66578 100 sched_info_dequeued sched_stats.h 177 0 15113 100 trace_workqueue_insertion workqueue.h 38 0 15107 100 trace_workqueue_execution workqueue.h 45 0 3622 100 syscall_trace_leave ptrace.c 1772 0 2750 100 sched_move_task sched.c 10100 0 2750 100 sched_move_task sched.c 10110 0 1815 100 pre_schedule_rt sched_rt.c 1462 0 837 100 audit_alloc auditsc.c 879 0 814 100 tcp_mss_split_point tcp_output.c 1302 Signed-off-by: Steven Rostedt --- kernel/trace/trace_branch.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c index 4a194f08f88c..b9bc4d470177 100644 --- a/kernel/trace/trace_branch.c +++ b/kernel/trace/trace_branch.c @@ -307,8 +307,23 @@ static int annotated_branch_stat_cmp(void *p1, void *p2) return -1; if (percent_a > percent_b) return 1; - else - return 0; + + if (a->incorrect < b->incorrect) + return -1; + if (a->incorrect > b->incorrect) + return 1; + + /* + * Since the above shows worse (incorrect) cases + * first, we continue that by showing best (correct) + * cases last. + */ + if (a->correct > b->correct) + return -1; + if (a->correct < b->correct) + return 1; + + return 0; } static struct tracer_stat annotated_branch_stats = { -- cgit v1.2.3 From c7c6b1fe9f942c1a30585ec2210a09dfff238506 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 10 Feb 2010 15:43:04 +0800 Subject: ftrace: Allow to remove a single function from function graph filter I don't see why we can only clear all functions from the filter. After patching: # echo sys_open > set_graph_function # echo sys_close >> set_graph_function # cat set_graph_function sys_open sys_close # echo '!sys_close' >> set_graph_function # cat set_graph_function sys_open Signed-off-by: Li Zefan LKML-Reference: <4B726388.2000408@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 51 +++++++++++++++++++++++++++++++-------------------- kernel/trace/trace.h | 3 ++- 2 files changed, 33 insertions(+), 21 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 7968762c8167..43bec993c864 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2426,6 +2426,7 @@ static const struct file_operations ftrace_notrace_fops = { static DEFINE_MUTEX(graph_lock); int ftrace_graph_count; +int ftrace_graph_filter_enabled; unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly; static void * @@ -2448,7 +2449,7 @@ static void *g_start(struct seq_file *m, loff_t *pos) mutex_lock(&graph_lock); /* Nothing, tell g_show to print all functions are enabled */ - if (!ftrace_graph_count && !*pos) + if (!ftrace_graph_filter_enabled && !*pos) return (void *)1; return __g_next(m, pos); @@ -2494,6 +2495,7 @@ ftrace_graph_open(struct inode *inode, struct file *file) mutex_lock(&graph_lock); if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + ftrace_graph_filter_enabled = 0; ftrace_graph_count = 0; memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs)); } @@ -2519,7 +2521,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) struct dyn_ftrace *rec; struct ftrace_page *pg; int search_len; - int found = 0; + int fail = 1; int type, not; char *search; bool exists; @@ -2530,37 +2532,51 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer) /* decode regex */ type = filter_parse_regex(buffer, strlen(buffer), &search, ¬); - if (not) - return -EINVAL; + if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS) + return -EBUSY; search_len = strlen(search); mutex_lock(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { - if (*idx >= FTRACE_GRAPH_MAX_FUNCS) - break; - if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE)) continue; if (ftrace_match_record(rec, search, search_len, type)) { - /* ensure it is not already in the array */ + /* if it is in the array */ exists = false; - for (i = 0; i < *idx; i++) + for (i = 0; i < *idx; i++) { if (array[i] == rec->ip) { exists = true; break; } - if (!exists) - array[(*idx)++] = rec->ip; - found = 1; + } + + if (!not) { + fail = 0; + if (!exists) { + array[(*idx)++] = rec->ip; + if (*idx >= FTRACE_GRAPH_MAX_FUNCS) + goto out; + } + } else { + if (exists) { + array[i] = array[--(*idx)]; + array[*idx] = 0; + fail = 0; + } + } } } while_for_each_ftrace_rec(); - +out: mutex_unlock(&ftrace_lock); - return found ? 0 : -EINVAL; + if (fail) + return -EINVAL; + + ftrace_graph_filter_enabled = 1; + return 0; } static ssize_t @@ -2570,16 +2586,11 @@ ftrace_graph_write(struct file *file, const char __user *ubuf, struct trace_parser parser; ssize_t read, ret; - if (!cnt || cnt < 0) + if (!cnt) return 0; mutex_lock(&graph_lock); - if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) { - ret = -EBUSY; - goto out_unlock; - } - if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) { ret = -ENOMEM; goto out_unlock; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ce077fbbf552..b477fce41edf 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -497,6 +497,7 @@ trace_print_graph_duration(unsigned long long duration, struct trace_seq *s); #ifdef CONFIG_DYNAMIC_FTRACE /* TODO: make this variable */ #define FTRACE_GRAPH_MAX_FUNCS 32 +extern int ftrace_graph_filter_enabled; extern int ftrace_graph_count; extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS]; @@ -504,7 +505,7 @@ static inline int ftrace_graph_addr(unsigned long addr) { int i; - if (!ftrace_graph_count) + if (!ftrace_graph_filter_enabled) return 1; for (i = 0; i < ftrace_graph_count; i++) { -- cgit v1.2.3 From 2225a122ae26d542bdce523d9d87a4a7ba10e07b Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Thu, 11 Feb 2010 11:51:00 -0800 Subject: ptrace: Add support for generic PTRACE_GETREGSET/PTRACE_SETREGSET Generic support for PTRACE_GETREGSET/PTRACE_SETREGSET commands which export the regsets supported by each architecture using the correponding NT_* types. These NT_* types are already part of the userland ABI, used in representing the architecture specific register sets as different NOTES in an ELF core file. 'addr' parameter for the ptrace system call encode the REGSET type (using the corresppnding NT_* type) and the 'data' parameter points to the struct iovec having the user buffer and the length of that buffer. struct iovec iov = { buf, len}; ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov); On successful completion, iov.len will be updated by the kernel specifying how much the kernel has written/read to/from the user's iov.buf. x86 extended state registers are primarily exported using this interface. Signed-off-by: Suresh Siddha LKML-Reference: <20100211195614.886724710@sbs-t61.sc.intel.com> Acked-by: Hongjiu Lu Cc: Roland McGrath Signed-off-by: H. Peter Anvin --- include/linux/elf.h | 6 +++- include/linux/ptrace.h | 15 +++++++++ kernel/ptrace.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 108 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/include/linux/elf.h b/include/linux/elf.h index a8c4af073ce9..d8e6e61ad9ff 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -349,7 +349,11 @@ typedef struct elf64_shdr { #define ELF_OSABI ELFOSABI_NONE #endif -/* Notes used in ET_CORE */ +/* + * Notes used in ET_CORE. Architectures export some of the arch register sets + * using the corresponding note types via the PTRACE_GETREGSET and + * PTRACE_SETREGSET requests. + */ #define NT_PRSTATUS 1 #define NT_PRFPREG 2 #define NT_PRPSINFO 3 diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 56f2d63a5cbb..dbfa821d5a6e 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -27,6 +27,21 @@ #define PTRACE_GETSIGINFO 0x4202 #define PTRACE_SETSIGINFO 0x4203 +/* + * Generic ptrace interface that exports the architecture specific regsets + * using the corresponding NT_* types (which are also used in the core dump). + * + * This interface usage is as follows: + * struct iovec iov = { buf, len}; + * + * ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov); + * + * On the successful completion, iov.len will be updated by the kernel, + * specifying how much the kernel has written/read to/from the user's iov.buf. + */ +#define PTRACE_GETREGSET 0x4204 +#define PTRACE_SETREGSET 0x4205 + /* options set using PTRACE_SETOPTIONS */ #define PTRACE_O_TRACESYSGOOD 0x00000001 #define PTRACE_O_TRACEFORK 0x00000002 diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 23bd09cd042e..13b4554d8fbb 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -22,6 +22,7 @@ #include #include #include +#include /* @@ -511,6 +512,47 @@ static int ptrace_resume(struct task_struct *child, long request, long data) return 0; } +#ifdef CONFIG_HAVE_ARCH_TRACEHOOK + +static const struct user_regset * +find_regset(const struct user_regset_view *view, unsigned int type) +{ + const struct user_regset *regset; + int n; + + for (n = 0; n < view->n; ++n) { + regset = view->regsets + n; + if (regset->core_note_type == type) + return regset; + } + + return NULL; +} + +static int ptrace_regset(struct task_struct *task, int req, unsigned int type, + struct iovec *kiov) +{ + const struct user_regset_view *view = task_user_regset_view(task); + const struct user_regset *regset = find_regset(view, type); + int regset_no; + + if (!regset || (kiov->iov_len % regset->size) != 0) + return -EIO; + + regset_no = regset - view->regsets; + kiov->iov_len = min(kiov->iov_len, + (__kernel_size_t) (regset->n * regset->size)); + + if (req == PTRACE_GETREGSET) + return copy_regset_to_user(task, view, regset_no, 0, + kiov->iov_len, kiov->iov_base); + else + return copy_regset_from_user(task, view, regset_no, 0, + kiov->iov_len, kiov->iov_base); +} + +#endif + int ptrace_request(struct task_struct *child, long request, long addr, long data) { @@ -573,6 +615,26 @@ int ptrace_request(struct task_struct *child, long request, return 0; return ptrace_resume(child, request, SIGKILL); +#ifdef CONFIG_HAVE_ARCH_TRACEHOOK + case PTRACE_GETREGSET: + case PTRACE_SETREGSET: + { + struct iovec kiov; + struct iovec __user *uiov = (struct iovec __user *) data; + + if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) + return -EFAULT; + + if (__get_user(kiov.iov_base, &uiov->iov_base) || + __get_user(kiov.iov_len, &uiov->iov_len)) + return -EFAULT; + + ret = ptrace_regset(child, request, addr, &kiov); + if (!ret) + ret = __put_user(kiov.iov_len, &uiov->iov_len); + break; + } +#endif default: break; } @@ -711,6 +773,32 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request, else ret = ptrace_setsiginfo(child, &siginfo); break; +#ifdef CONFIG_HAVE_ARCH_TRACEHOOK + case PTRACE_GETREGSET: + case PTRACE_SETREGSET: + { + struct iovec kiov; + struct compat_iovec __user *uiov = + (struct compat_iovec __user *) datap; + compat_uptr_t ptr; + compat_size_t len; + + if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov))) + return -EFAULT; + + if (__get_user(ptr, &uiov->iov_base) || + __get_user(len, &uiov->iov_len)) + return -EFAULT; + + kiov.iov_base = compat_ptr(ptr); + kiov.iov_len = len; + + ret = ptrace_regset(child, request, addr, &kiov); + if (!ret) + ret = __put_user(kiov.iov_len, &uiov->iov_len); + break; + } +#endif default: ret = ptrace_request(child, request, addr, data); -- cgit v1.2.3 From 6f93d0a7c83772997b81c30d6f519a9a5dbab6a9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sun, 14 Feb 2010 11:12:04 +0100 Subject: perf_events: Fix FORK events Commit 22e19085 ("Honour event state for aux stream data") introduced a bug where we would drop FORK events. The thing is that we deliver FORK events to the child process' event, which at that time will be PERF_EVENT_STATE_INACTIVE because the child won't be scheduled in (we're in the middle of fork). Solve this twice, change the event state filter to exclude only disabled (STATE_OFF) or worse, and deliver FORK events to the current (parent). Signed-off-by: Peter Zijlstra Cc: Anton Blanchard Cc: Arnaldo Carvalho de Melo LKML-Reference: <1266142324.5273.411.camel@laptop> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 2b19297742cb..2ae7409bf38f 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3259,8 +3259,6 @@ static void perf_event_task_output(struct perf_event *event, task_event->event_id.tid = perf_event_tid(event, task); task_event->event_id.ptid = perf_event_tid(event, current); - task_event->event_id.time = perf_clock(); - perf_output_put(&handle, task_event->event_id); perf_output_end(&handle); @@ -3268,7 +3266,7 @@ static void perf_event_task_output(struct perf_event *event, static int perf_event_task_match(struct perf_event *event) { - if (event->state != PERF_EVENT_STATE_ACTIVE) + if (event->state < PERF_EVENT_STATE_INACTIVE) return 0; if (event->cpu != -1 && event->cpu != smp_processor_id()) @@ -3300,7 +3298,7 @@ static void perf_event_task_event(struct perf_task_event *task_event) cpuctx = &get_cpu_var(perf_cpu_context); perf_event_task_ctx(&cpuctx->ctx, task_event); if (!ctx) - ctx = rcu_dereference(task_event->task->perf_event_ctxp); + ctx = rcu_dereference(current->perf_event_ctxp); if (ctx) perf_event_task_ctx(ctx, task_event); put_cpu_var(perf_cpu_context); @@ -3331,6 +3329,7 @@ static void perf_event_task(struct task_struct *task, /* .ppid */ /* .tid */ /* .ptid */ + .time = perf_clock(), }, }; @@ -3380,7 +3379,7 @@ static void perf_event_comm_output(struct perf_event *event, static int perf_event_comm_match(struct perf_event *event) { - if (event->state != PERF_EVENT_STATE_ACTIVE) + if (event->state < PERF_EVENT_STATE_INACTIVE) return 0; if (event->cpu != -1 && event->cpu != smp_processor_id()) @@ -3500,7 +3499,7 @@ static void perf_event_mmap_output(struct perf_event *event, static int perf_event_mmap_match(struct perf_event *event, struct perf_mmap_event *mmap_event) { - if (event->state != PERF_EVENT_STATE_ACTIVE) + if (event->state < PERF_EVENT_STATE_INACTIVE) return 0; if (event->cpu != -1 && event->cpu != smp_processor_id()) -- cgit v1.2.3 From 8b833c506c05c498d4215e2c260be44225daf6de Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Fri, 5 Feb 2010 01:24:34 -0500 Subject: kprobes: Add mcount to the kprobes blacklist Since mcount function can be called from everywhere, it should be blacklisted. Moreover, the "mcount" symbol is a special symbol name. So, it is better to put it in the generic blacklist. Signed-off-by: Masami Hiramatsu Cc: systemtap Cc: DLE Cc: Ananth N Mavinakayanahalli Cc: Steven Rostedt LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Ingo Molnar --- kernel/kprobes.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b7df302a0204..c4b43430d393 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -93,6 +93,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = { {"native_get_debugreg",}, {"irq_entries_start",}, {"common_interrupt",}, + {"mcount",}, /* mcount can be called from everywhere */ {NULL} /* Terminator */ }; -- cgit v1.2.3 From 9000f05c6d1607f79c0deacf42b09693be673f4c Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Fri, 12 Feb 2010 17:14:22 -0800 Subject: sched: Fix SMT scheduler regression in find_busiest_queue() Fix a SMT scheduler performance regression that is leading to a scenario where SMT threads in one core are completely idle while both the SMT threads in another core (on the same socket) are busy. This is caused by this commit (with the problematic code highlighted) commit bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1 Author: Peter Zijlstra Date: Tue Sep 1 10:34:38 2009 +0200 sched: Try to deal with low capacity @@ -4203,15 +4223,18 @@ find_busiest_queue() ... for_each_cpu(i, sched_group_cpus(group)) { + unsigned long power = power_of(i); ... - wl = weighted_cpuload(i); + wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; + wl /= power; - if (rq->nr_running == 1 && wl > imbalance) + if (capacity && rq->nr_running == 1 && wl > imbalance) continue; On a SMT system, power of the HT logical cpu will be 589 and the scheduler load imbalance (for scenarios like the one mentioned above) can be approximately 1024 (SCHED_LOAD_SCALE). The above change of scaling the weighted load with the power will result in "wl > imbalance" and ultimately resulting in find_busiest_queue() return NULL, causing load_balance() to think that the load is well balanced. But infact one of the tasks can be moved to the idle core for optimal performance. We don't need to use the weighted load (wl) scaled by the cpu power to compare with imabalance. In that condition, we already know there is only a single task "rq->nr_running == 1" and the comparison between imbalance, wl is to make sure that we select the correct priority thread which matches imbalance. So we really need to compare the imabalnce with the original weighted load of the cpu and not the scaled load. But in other conditions where we want the most hammered(busiest) cpu, we can use scaled load to ensure that we consider the cpu power in addition to the actual load on that cpu, so that we can move the load away from the guy that is getting most hammered with respect to the actual capacity, as compared with the rest of the cpu's in that busiest group. Fix it. Reported-by: Ma Ling Initial-Analysis-by: Zhang, Yanmin Signed-off-by: Suresh Siddha Signed-off-by: Peter Zijlstra LKML-Reference: <1266023662.2808.118.camel@sbs-t61.sc.intel.com> Cc: stable@kernel.org [2.6.32.x] Signed-off-by: Thomas Gleixner --- kernel/sched.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index e3199df426e3..4d78aef4559d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4119,12 +4119,23 @@ find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, continue; rq = cpu_rq(i); - wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; - wl /= power; + wl = weighted_cpuload(i); + /* + * When comparing with imbalance, use weighted_cpuload() + * which is not scaled with the cpu power. + */ if (capacity && rq->nr_running == 1 && wl > imbalance) continue; + /* + * For the load comparisons with the other cpu's, consider + * the weighted_cpuload() scaled with the cpu power, so that + * the load can be moved away from the cpu that is potentially + * running at a lower capacity. + */ + wl = (wl * SCHED_LOAD_SCALE) / power; + if (wl > max_load) { max_load = wl; busiest = rq; -- cgit v1.2.3 From 0970d2992dfd7d5ec2c787417cf464f01eeaf42a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 15 Feb 2010 14:45:54 +0100 Subject: sched: Fix race between ttwu() and task_rq_lock() Thomas found that due to ttwu() changing a task's cpu without holding the rq->lock, task_rq_lock() might end up locking the wrong rq. Avoid this by serializing against TASK_WAKING. Reported-by: Thomas Gleixner Signed-off-by: Peter Zijlstra LKML-Reference: <1266241712.15770.420.camel@laptop> Signed-off-by: Thomas Gleixner --- kernel/sched.c | 73 ++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 46 insertions(+), 27 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 4d78aef4559d..404e2017c0cf 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -940,6 +940,19 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) } #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ +/* + * Check whether the task is waking, we use this to synchronize against + * ttwu() so that task_cpu() reports a stable number. + * + * We need to make an exception for PF_STARTING tasks because the fork + * path might require task_rq_lock() to work, eg. it can call + * set_cpus_allowed_ptr() from the cpuset clone_ns code. + */ +static inline int task_is_waking(struct task_struct *p) +{ + return unlikely((p->state == TASK_WAKING) && !(p->flags & PF_STARTING)); +} + /* * __task_rq_lock - lock the runqueue a given task resides on. * Must be called interrupts disabled. @@ -947,10 +960,14 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) static inline struct rq *__task_rq_lock(struct task_struct *p) __acquires(rq->lock) { + struct rq *rq; + for (;;) { - struct rq *rq = task_rq(p); + while (task_is_waking(p)) + cpu_relax(); + rq = task_rq(p); raw_spin_lock(&rq->lock); - if (likely(rq == task_rq(p))) + if (likely(rq == task_rq(p) && !task_is_waking(p))) return rq; raw_spin_unlock(&rq->lock); } @@ -967,10 +984,12 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) struct rq *rq; for (;;) { + while (task_is_waking(p)) + cpu_relax(); local_irq_save(*flags); rq = task_rq(p); raw_spin_lock(&rq->lock); - if (likely(rq == task_rq(p))) + if (likely(rq == task_rq(p) && !task_is_waking(p))) return rq; raw_spin_unlock_irqrestore(&rq->lock, *flags); } @@ -2408,14 +2427,27 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, __task_rq_unlock(rq); cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); - if (cpu != orig_cpu) + if (cpu != orig_cpu) { + /* + * Since we migrate the task without holding any rq->lock, + * we need to be careful with task_rq_lock(), since that + * might end up locking an invalid rq. + */ set_task_cpu(p, cpu); + } - rq = __task_rq_lock(p); + rq = cpu_rq(cpu); + raw_spin_lock(&rq->lock); update_rq_clock(rq); + /* + * We migrated the task without holding either rq->lock, however + * since the task is not on the task list itself, nobody else + * will try and migrate the task, hence the rq should match the + * cpu we just moved it to. + */ + WARN_ON(task_cpu(p) != cpu); WARN_ON(p->state != TASK_WAKING); - cpu = task_cpu(p); #ifdef CONFIG_SCHEDSTATS schedstat_inc(rq, ttwu_count); @@ -2647,7 +2679,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) { unsigned long flags; struct rq *rq; - int cpu __maybe_unused = get_cpu(); + int cpu = get_cpu(); #ifdef CONFIG_SMP /* @@ -2663,7 +2695,13 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) set_task_cpu(p, cpu); #endif - rq = task_rq_lock(p, &flags); + /* + * Since the task is not on the rq and we still have TASK_WAKING set + * nobody else will migrate this task. + */ + rq = cpu_rq(cpu); + raw_spin_lock_irqsave(&rq->lock, flags); + BUG_ON(p->state != TASK_WAKING); p->state = TASK_RUNNING; update_rq_clock(rq); @@ -7156,27 +7194,8 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) struct rq *rq; int ret = 0; - /* - * Since we rely on wake-ups to migrate sleeping tasks, don't change - * the ->cpus_allowed mask from under waking tasks, which would be - * possible when we change rq->lock in ttwu(), so synchronize against - * TASK_WAKING to avoid that. - * - * Make an exception for freshly cloned tasks, since cpuset namespaces - * might move the task about, we have to validate the target in - * wake_up_new_task() anyway since the cpu might have gone away. - */ -again: - while (p->state == TASK_WAKING && !(p->flags & PF_STARTING)) - cpu_relax(); - rq = task_rq_lock(p, &flags); - if (p->state == TASK_WAKING && !(p->flags & PF_STARTING)) { - task_rq_unlock(rq, &flags); - goto again; - } - if (!cpumask_intersects(new_mask, cpu_active_mask)) { ret = -EINVAL; goto out; -- cgit v1.2.3 From 83ab0aa0d5623d823444db82c3b3c34d7ec364ae Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 17 Feb 2010 09:05:48 +0100 Subject: sched: Don't use possibly stale sched_class setscheduler() saves task->sched_class outside of the rq->lock held region for a check after the setscheduler changes have become effective. That might result in checking a stale value. rtmutex_setprio() has the same problem, though it is protected by p->pi_lock against setscheduler(), but for correctness sake (and to avoid bad examples) it needs to be fixed as well. Retrieve task->sched_class inside of the rq->lock held region. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Cc: stable@kernel.org --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index af5fa239804d..0b914fc90a55 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4249,7 +4249,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) unsigned long flags; int oldprio, on_rq, running; struct rq *rq; - const struct sched_class *prev_class = p->sched_class; + const struct sched_class *prev_class; BUG_ON(prio < 0 || prio > MAX_PRIO); @@ -4257,6 +4257,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio) update_rq_clock(rq); oldprio = p->prio; + prev_class = p->sched_class; on_rq = p->se.on_rq; running = task_current(rq, p); if (on_rq) @@ -4476,7 +4477,7 @@ static int __sched_setscheduler(struct task_struct *p, int policy, { int retval, oldprio, oldpolicy = -1, on_rq, running; unsigned long flags; - const struct sched_class *prev_class = p->sched_class; + const struct sched_class *prev_class; struct rq *rq; int reset_on_fork; @@ -4590,6 +4591,7 @@ recheck: p->sched_reset_on_fork = reset_on_fork; oldprio = p->prio; + prev_class = p->sched_class; __setscheduler(rq, p, policy, param->sched_priority); if (running) -- cgit v1.2.3 From e7b8e675d9c71b868b66f62f725a948047514719 Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Tue, 26 Jan 2010 04:40:03 -0500 Subject: tracing: Unify arch_syscall_addr() implementations Most implementations of arch_syscall_addr() are the same, so create a default version in common code and move the one piece that differs (the syscall table) to asm/syscall.h. New arch ports don't have to waste time copying & pasting this simple function. The s390/sparc versions need to be different, so document why. Signed-off-by: Mike Frysinger Acked-by: David S. Miller Acked-by: Paul Mundt Acked-by: Heiko Carstens Cc: Steven Rostedt LKML-Reference: <1264498803-17278-1-git-send-email-vapier@gentoo.org> Signed-off-by: Frederic Weisbecker --- Documentation/trace/ftrace-design.txt | 5 ++--- arch/s390/include/asm/syscall.h | 7 +++++++ arch/s390/kernel/ftrace.c | 10 ---------- arch/sh/include/asm/syscall.h | 2 ++ arch/sh/kernel/ftrace.c | 9 --------- arch/sparc/include/asm/syscall.h | 7 +++++++ arch/sparc/kernel/ftrace.c | 11 ----------- arch/x86/include/asm/syscall.h | 2 ++ arch/x86/kernel/ftrace.c | 10 ---------- include/linux/ftrace.h | 6 ++++++ kernel/trace/trace_syscalls.c | 5 +++++ 11 files changed, 31 insertions(+), 43 deletions(-) (limited to 'kernel') diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt index 239f14b2b55a..99df1101d2a5 100644 --- a/Documentation/trace/ftrace-design.txt +++ b/Documentation/trace/ftrace-design.txt @@ -218,11 +218,10 @@ HAVE_SYSCALL_TRACEPOINTS You need very few things to get the syscalls tracing in an arch. +- Support HAVE_ARCH_TRACEHOOK (see arch/Kconfig). - Have a NR_syscalls variable in that provides the number of syscalls supported by the arch. -- Implement arch_syscall_addr() that resolves a syscall address from a - syscall number. -- Support the TIF_SYSCALL_TRACEPOINT thread flags +- Support the TIF_SYSCALL_TRACEPOINT thread flags. - Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace in the ptrace syscalls tracing path. - Tag this arch as HAVE_SYSCALL_TRACEPOINTS. diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h index e0a73d3eb837..8429686951f9 100644 --- a/arch/s390/include/asm/syscall.h +++ b/arch/s390/include/asm/syscall.h @@ -15,6 +15,13 @@ #include #include +/* + * The syscall table always contains 32 bit pointers since we know that the + * address of the function to be called is (way) below 4GB. So the "int" + * type here is what we want [need] for both 32 bit and 64 bit systems. + */ +extern const unsigned int sys_call_table[]; + static inline long syscall_get_nr(struct task_struct *task, struct pt_regs *regs) { diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 5a82bc68193e..9e69449e77ad 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -200,13 +200,3 @@ out: return parent; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -#ifdef CONFIG_FTRACE_SYSCALLS - -extern unsigned int sys_call_table[]; - -unsigned long __init arch_syscall_addr(int nr) -{ - return (unsigned long)sys_call_table[nr]; -} -#endif diff --git a/arch/sh/include/asm/syscall.h b/arch/sh/include/asm/syscall.h index 6a381429ee9d..aa7777bdc370 100644 --- a/arch/sh/include/asm/syscall.h +++ b/arch/sh/include/asm/syscall.h @@ -1,6 +1,8 @@ #ifndef __ASM_SH_SYSCALL_H #define __ASM_SH_SYSCALL_H +extern const unsigned long sys_call_table[]; + #ifdef CONFIG_SUPERH32 # include "syscall_32.h" #else diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c index a48cdedc73b5..30e13196d35b 100644 --- a/arch/sh/kernel/ftrace.c +++ b/arch/sh/kernel/ftrace.c @@ -399,12 +399,3 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -#ifdef CONFIG_FTRACE_SYSCALLS -extern unsigned long *sys_call_table; - -unsigned long __init arch_syscall_addr(int nr) -{ - return (unsigned long)sys_call_table[nr]; -} -#endif /* CONFIG_FTRACE_SYSCALLS */ diff --git a/arch/sparc/include/asm/syscall.h b/arch/sparc/include/asm/syscall.h index 7486c605e23c..025a02ad2e31 100644 --- a/arch/sparc/include/asm/syscall.h +++ b/arch/sparc/include/asm/syscall.h @@ -5,6 +5,13 @@ #include #include +/* + * The syscall table always contains 32 bit pointers since we know that the + * address of the function to be called is (way) below 4GB. So the "int" + * type here is what we want [need] for both 32 bit and 64 bit systems. + */ +extern const unsigned int sys_call_table[]; + /* The system call number is given by the user in %g1 */ static inline long syscall_get_nr(struct task_struct *task, struct pt_regs *regs) diff --git a/arch/sparc/kernel/ftrace.c b/arch/sparc/kernel/ftrace.c index 29973daa9930..9103a56b39e8 100644 --- a/arch/sparc/kernel/ftrace.c +++ b/arch/sparc/kernel/ftrace.c @@ -91,14 +91,3 @@ int __init ftrace_dyn_arch_init(void *data) return 0; } #endif - -#ifdef CONFIG_FTRACE_SYSCALLS - -extern unsigned int sys_call_table[]; - -unsigned long __init arch_syscall_addr(int nr) -{ - return (unsigned long)sys_call_table[nr]; -} - -#endif diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h index 8d33bc5462d1..c4a348f7bd43 100644 --- a/arch/x86/include/asm/syscall.h +++ b/arch/x86/include/asm/syscall.h @@ -16,6 +16,8 @@ #include #include +extern const unsigned long sys_call_table[]; + /* * Only the low 32 bits of orig_ax are meaningful, so we return int. * This importantly ignores the high bits on 64-bit, so comparisons diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 309689245431..0d93a941934c 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -484,13 +484,3 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -#ifdef CONFIG_FTRACE_SYSCALLS - -extern unsigned long *sys_call_table; - -unsigned long __init arch_syscall_addr(int nr) -{ - return (unsigned long)(&sys_call_table)[nr]; -} -#endif diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 0b4f97d24d7f..1cbb36f2759c 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -511,4 +511,10 @@ static inline void trace_hw_branch_oops(void) {} #endif /* CONFIG_HW_BRANCH_TRACER */ +#ifdef CONFIG_FTRACE_SYSCALLS + +unsigned long arch_syscall_addr(int nr); + +#endif /* CONFIG_FTRACE_SYSCALLS */ + #endif /* _LINUX_FTRACE_H */ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 49cea70fbf6d..ecf00782b46c 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -394,6 +394,11 @@ int init_syscall_trace(struct ftrace_event_call *call) return id; } +unsigned long __init arch_syscall_addr(int nr) +{ + return (unsigned long)sys_call_table[nr]; +} + int __init init_ftrace_syscalls(void) { struct syscall_metadata *meta; -- cgit v1.2.3 From f850c30c8b426ba1688cb63b1a3e534eed03a138 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Wed, 10 Feb 2010 17:25:17 +0100 Subject: tracing/kprobes: Make Kconfig dependencies generic KPROBES_EVENT actually depends on the regs and stack access API (b1cf540f) and not on x86. So introduce a new config option which architectures can select if they have the API implemented and switch x86. Signed-off-by: Heiko Carstens Acked-by: Masami Hiramatsu Cc: Ingo Molnar Cc: Martin Schwidefsky LKML-Reference: <20100210162517.GB6933@osiris.boeblingen.de.ibm.com> Signed-off-by: Frederic Weisbecker --- arch/Kconfig | 3 +++ arch/x86/Kconfig | 1 + kernel/trace/Kconfig | 2 +- 3 files changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/arch/Kconfig b/arch/Kconfig index 9d055b4f0585..04e3aa77da25 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -121,6 +121,9 @@ config HAVE_DMA_ATTRS config USE_GENERIC_SMP_HELPERS bool +config HAVE_REGS_AND_STACK_ACCESS_API + bool + config HAVE_CLK bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 55298e891571..07baa12929b4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -45,6 +45,7 @@ config X86 select HAVE_GENERIC_DMA_COHERENT if X86_32 select HAVE_EFFICIENT_UNALIGNED_ACCESS select USER_STACKTRACE_SUPPORT + select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_DMA_API_DEBUG select HAVE_KERNEL_GZIP select HAVE_KERNEL_BZIP2 diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 6c22d8a2f289..40fef552f012 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -451,7 +451,7 @@ config BLK_DEV_IO_TRACE config KPROBE_EVENT depends on KPROBES - depends on X86 + depends on HAVE_REGS_AND_STACK_ACCESS_API bool "Enable kprobes-based dynamic events" select TRACING default y -- cgit v1.2.3 From b26b2d494b659f988b4d75eb394dfa0ddac415c9 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Fri, 1 Jan 2010 17:40:49 +0100 Subject: resource/PCI: align functions now return start of resource As suggested by Linus, align functions should return the start of a resource, not void. An update of "res->start" is no longer necessary. Cc: Bjorn Helgaas Cc: Yinghai Lu Signed-off-by: Dominik Brodowski Signed-off-by: Jesse Barnes --- arch/alpha/kernel/pci.c | 4 ++-- arch/arm/kernel/bios32.c | 8 +++++--- arch/cris/arch-v32/drivers/pci/bios.c | 14 ++++++-------- arch/frv/mb93090-mb00/pci-frv.c | 14 ++++++-------- arch/ia64/pci/pci.c | 3 ++- arch/mips/pci/pci.c | 4 ++-- arch/mips/pmc-sierra/yosemite/ht.c | 10 +++++----- arch/mn10300/unit-asb2305/pci-asb2305.c | 16 +++++++--------- arch/parisc/kernel/pci.c | 10 +++++----- arch/powerpc/kernel/pci-common.c | 13 ++++++------- arch/sh/drivers/pci/pci.c | 6 +++--- arch/sparc/kernel/pci.c | 5 +++-- arch/sparc/kernel/pcic.c | 5 +++-- arch/x86/pci/i386.c | 12 +++++------- arch/xtensa/kernel/pci.c | 11 +++++------ drivers/pci/bus.c | 6 ++++-- drivers/pcmcia/rsrc_mgr.c | 12 ++++++------ drivers/pcmcia/rsrc_nonstatic.c | 16 +++++++++------- include/linux/ioport.h | 6 ++++-- include/linux/pci.h | 8 +++++--- kernel/resource.c | 14 +++++++++----- 21 files changed, 102 insertions(+), 95 deletions(-) (limited to 'kernel') diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c index a91ba28999b5..5cf111ed851c 100644 --- a/arch/alpha/kernel/pci.c +++ b/arch/alpha/kernel/pci.c @@ -126,7 +126,7 @@ DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, pcibios_fixup_final); #define MB (1024*KB) #define GB (1024*MB) -void +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { @@ -184,7 +184,7 @@ pcibios_align_resource(void *data, struct resource *res, } } - res->start = start; + return start; } #undef KB #undef MB diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c index 809681900ec8..a7c85f84f06c 100644 --- a/arch/arm/kernel/bios32.c +++ b/arch/arm/kernel/bios32.c @@ -616,15 +616,17 @@ char * __init pcibios_setup(char *str) * but we want to try to avoid allocating at 0x2900-0x2bff * which might be mirrored at 0x0100-0x03ff.. */ -void pcibios_align_resource(void *data, struct resource *res, - resource_size_t size, resource_size_t align) +resource_size_t pcibios_align_resource(void *data, struct resource *res, + resource_size_t size, resource_size_t align) { resource_size_t start = res->start; if (res->flags & IORESOURCE_IO && start & 0x300) start = (start + 0x3ff) & ~0x3ff; - res->start = (start + align - 1) & ~(align - 1); + start = (start + align - 1) & ~(align - 1); + + return start; } /** diff --git a/arch/cris/arch-v32/drivers/pci/bios.c b/arch/cris/arch-v32/drivers/pci/bios.c index 77ee319193c3..5811e2f8945c 100644 --- a/arch/cris/arch-v32/drivers/pci/bios.c +++ b/arch/cris/arch-v32/drivers/pci/bios.c @@ -41,18 +41,16 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, return 0; } -void +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { - if (res->flags & IORESOURCE_IO) { - resource_size_t start = res->start; + resource_size_t start = res->start; - if (start & 0x300) { - start = (start + 0x3ff) & ~0x3ff; - res->start = start; - } - } + if ((res->flags & IORESOURCE_IO) && (start & 0x300)) + start = (start + 0x3ff) & ~0x3ff; + + return start } int pcibios_enable_resources(struct pci_dev *dev, int mask) diff --git a/arch/frv/mb93090-mb00/pci-frv.c b/arch/frv/mb93090-mb00/pci-frv.c index 566bdeb499d1..c947aa43f2a9 100644 --- a/arch/frv/mb93090-mb00/pci-frv.c +++ b/arch/frv/mb93090-mb00/pci-frv.c @@ -32,18 +32,16 @@ * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -void +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { - if (res->flags & IORESOURCE_IO) { - resource_size_t start = res->start; + resource_size_t start = res->start; - if (start & 0x300) { - start = (start + 0x3ff) & ~0x3ff; - res->start = start; - } - } + if ((res->flags & IORESOURCE_IO) && (start & 0x300)) + start = (start + 0x3ff) & ~0x3ff; + + return start } diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c index df639db779f9..ef574cd311d1 100644 --- a/arch/ia64/pci/pci.c +++ b/arch/ia64/pci/pci.c @@ -547,10 +547,11 @@ pcibios_disable_device (struct pci_dev *dev) acpi_pci_irq_disable(dev); } -void +resource_size_t pcibios_align_resource (void *data, struct resource *res, resource_size_t size, resource_size_t align) { + return res->start; } /* diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c index 9a11c2226891..9085988f7cf3 100644 --- a/arch/mips/pci/pci.c +++ b/arch/mips/pci/pci.c @@ -49,7 +49,7 @@ static int pci_initialized; * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -void +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { @@ -73,7 +73,7 @@ pcibios_align_resource(void *data, struct resource *res, start = PCIBIOS_MIN_MEM + hose->mem_resource->start; } - res->start = start; + return start; } static void __devinit pcibios_scanbus(struct pci_controller *hose) diff --git a/arch/mips/pmc-sierra/yosemite/ht.c b/arch/mips/pmc-sierra/yosemite/ht.c index 678388fd34b1..5e410087b628 100644 --- a/arch/mips/pmc-sierra/yosemite/ht.c +++ b/arch/mips/pmc-sierra/yosemite/ht.c @@ -345,14 +345,13 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) return pcibios_enable_resources(dev); } -void pcibios_align_resource(void *data, struct resource *res, - resource_size_t size, resource_size_t align) +resource_size_t pcibios_align_resource(void *data, struct resource *res, + resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; + resource_size_t start = res->start; if (res->flags & IORESOURCE_IO) { - resource_size_t start = res->start; - /* We need to avoid collisions with `mirrored' VGA ports and other strange ISA hardware, so we always want the addresses kilobyte aligned. */ @@ -363,8 +362,9 @@ void pcibios_align_resource(void *data, struct resource *res, } start = (start + 1024 - 1) & ~(1024 - 1); - res->start = start; } + + return start; } struct pci_ops titan_pci_ops = { diff --git a/arch/mn10300/unit-asb2305/pci-asb2305.c b/arch/mn10300/unit-asb2305/pci-asb2305.c index 78cd134ddf7d..b0b3758fba08 100644 --- a/arch/mn10300/unit-asb2305/pci-asb2305.c +++ b/arch/mn10300/unit-asb2305/pci-asb2305.c @@ -31,9 +31,11 @@ * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -void pcibios_align_resource(void *data, struct resource *res, - resource_size_t size, resource_size_t align) +resource_size_t pcibios_align_resource(void *data, struct resource *res, + resource_size_t size, resource_size_t align) { + resource_size_t start = res->start; + #if 0 struct pci_dev *dev = data; @@ -47,14 +49,10 @@ void pcibios_align_resource(void *data, struct resource *res, ); #endif - if (res->flags & IORESOURCE_IO) { - unsigned long start = res->start; + if ((res->flags & IORESOURCE_IO) && (start & 0x300)) + start = (start + 0x3ff) & ~0x3ff; - if (start & 0x300) { - start = (start + 0x3ff) & ~0x3ff; - res->start = start; - } - } + return start; } diff --git a/arch/parisc/kernel/pci.c b/arch/parisc/kernel/pci.c index f7064abc3bb6..4463a31973ba 100644 --- a/arch/parisc/kernel/pci.c +++ b/arch/parisc/kernel/pci.c @@ -254,10 +254,10 @@ EXPORT_SYMBOL(pcibios_bus_to_resource); * Since we are just checking candidates, don't use any fields other * than res->start. */ -void pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t alignment) { - resource_size_t mask, align; + resource_size_t mask, align, start = res->start; DBG_RES("pcibios_align_resource(%s, (%p) [%lx,%lx]/%x, 0x%lx, 0x%lx)\n", pci_name(((struct pci_dev *) data)), @@ -269,10 +269,10 @@ void pcibios_align_resource(void *data, struct resource *res, /* Align to largest of MIN or input size */ mask = max(alignment, align) - 1; - res->start += mask; - res->start &= ~mask; + start += mask; + start &= ~mask; - /* The caller updates the end field, we don't. */ + return start; } diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index cadbed679fbb..d7eebbaf01f1 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c @@ -1181,21 +1181,20 @@ static int skip_isa_ioresource_align(struct pci_dev *dev) * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -void pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; + resource_size_t start = res->start; if (res->flags & IORESOURCE_IO) { - resource_size_t start = res->start; - if (skip_isa_ioresource_align(dev)) - return; - if (start & 0x300) { + return start; + if (start & 0x300) start = (start + 0x3ff) & ~0x3ff; - res->start = start; - } } + + return start; } EXPORT_SYMBOL(pcibios_align_resource); diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c index c481df639022..b36ca825b3d3 100644 --- a/arch/sh/drivers/pci/pci.c +++ b/arch/sh/drivers/pci/pci.c @@ -148,8 +148,8 @@ void __devinit pcibios_fixup_bus(struct pci_bus *bus) * addresses to be allocated in the 0x000-0x0ff region * modulo 0x400. */ -void pcibios_align_resource(void *data, struct resource *res, - resource_size_t size, resource_size_t align) +resource_size_t pcibios_align_resource(void *data, struct resource *res, + resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; struct pci_channel *chan = dev->sysdata; @@ -171,7 +171,7 @@ void pcibios_align_resource(void *data, struct resource *res, start = PCIBIOS_MIN_MEM + chan->mem_resource->start; } - res->start = start; + return start; } void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region, diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c index 592b03d85167..d56c1f34689e 100644 --- a/arch/sparc/kernel/pci.c +++ b/arch/sparc/kernel/pci.c @@ -722,9 +722,10 @@ void pcibios_update_irq(struct pci_dev *pdev, int irq) { } -void pcibios_align_resource(void *data, struct resource *res, - resource_size_t size, resource_size_t align) +resource_size_t pcibios_align_resource(void *data, struct resource *res, + resource_size_t size, resource_size_t align) { + return res->start; } int pcibios_enable_device(struct pci_dev *dev, int mask) diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c index 4e2724ec2bb6..46fda64ff163 100644 --- a/arch/sparc/kernel/pcic.c +++ b/arch/sparc/kernel/pcic.c @@ -768,9 +768,10 @@ char * __devinit pcibios_setup(char *str) return str; } -void pcibios_align_resource(void *data, struct resource *res, - resource_size_t size, resource_size_t align) +resource_size_t pcibios_align_resource(void *data, struct resource *res, + resource_size_t size, resource_size_t align) { + return res->start; } int pcibios_enable_device(struct pci_dev *pdev, int mask) diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c index 5dc9e8c63fcd..924e40c916d3 100644 --- a/arch/x86/pci/i386.c +++ b/arch/x86/pci/i386.c @@ -60,22 +60,20 @@ skip_isa_ioresource_align(struct pci_dev *dev) { * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -void +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; + resource_size_t start = res->start; if (res->flags & IORESOURCE_IO) { - resource_size_t start = res->start; - if (skip_isa_ioresource_align(dev)) - return; - if (start & 0x300) { + return start; + if (start & 0x300) start = (start + 0x3ff) & ~0x3ff; - res->start = start; - } } + return start; } EXPORT_SYMBOL(pcibios_align_resource); diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c index b7c073484e01..d7efab03164e 100644 --- a/arch/xtensa/kernel/pci.c +++ b/arch/xtensa/kernel/pci.c @@ -69,26 +69,25 @@ static int pci_bus_count; * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -void +resource_size_t pcibios_align_resource(void *data, struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; + resource_size_t start = res->start; if (res->flags & IORESOURCE_IO) { - resource_size_t start = res->start; - if (size > 0x100) { printk(KERN_ERR "PCI: I/O Region %s/%d too large" " (%ld bytes)\n", pci_name(dev), dev->resource - res, size); } - if (start & 0x300) { + if (start & 0x300) start = (start + 0x3ff) & ~0x3ff; - res->start = start; - } } + + return start; } int diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index cef28a79103f..d29d69a37940 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -36,8 +36,10 @@ int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res, resource_size_t size, resource_size_t align, resource_size_t min, unsigned int type_mask, - void (*alignf)(void *, struct resource *, resource_size_t, - resource_size_t), + resource_size_t (*alignf)(void *, + struct resource *, + resource_size_t, + resource_size_t), void *alignf_data) { int i, ret = -ENOMEM; diff --git a/drivers/pcmcia/rsrc_mgr.c b/drivers/pcmcia/rsrc_mgr.c index 52db17263d8b..f92a2dac13a2 100644 --- a/drivers/pcmcia/rsrc_mgr.c +++ b/drivers/pcmcia/rsrc_mgr.c @@ -114,22 +114,20 @@ struct pcmcia_align_data { unsigned long offset; }; -static void pcmcia_align(void *align_data, struct resource *res, - unsigned long size, unsigned long align) +static resource_size_t pcmcia_align(void *align_data, struct resource *res, + resource_size_t size, resource_size_t align) { struct pcmcia_align_data *data = align_data; - unsigned long start; + resource_size_t start; start = (res->start & ~data->mask) + data->offset; if (start < res->start) start += data->mask + 1; - res->start = start; #ifdef CONFIG_X86 if (res->flags & IORESOURCE_IO) { if (start & 0x300) { start = (start + 0x3ff) & ~0x3ff; - res->start = start; } } #endif @@ -137,9 +135,11 @@ static void pcmcia_align(void *align_data, struct resource *res, #ifdef CONFIG_M68K if (res->flags & IORESOURCE_IO) { if ((res->start + size - 1) >= 1024) - res->start = res->end; + start = res->end; } #endif + + return start; } diff --git a/drivers/pcmcia/rsrc_nonstatic.c b/drivers/pcmcia/rsrc_nonstatic.c index 9b0dc433a8c3..b65902870e44 100644 --- a/drivers/pcmcia/rsrc_nonstatic.c +++ b/drivers/pcmcia/rsrc_nonstatic.c @@ -533,7 +533,7 @@ struct pcmcia_align_data { struct resource_map *map; }; -static void +static resource_size_t pcmcia_common_align(void *align_data, struct resource *res, resource_size_t size, resource_size_t align) { @@ -545,17 +545,18 @@ pcmcia_common_align(void *align_data, struct resource *res, start = (res->start & ~data->mask) + data->offset; if (start < res->start) start += data->mask + 1; - res->start = start; + return start; } -static void +static resource_size_t pcmcia_align(void *align_data, struct resource *res, resource_size_t size, resource_size_t align) { struct pcmcia_align_data *data = align_data; struct resource_map *m; + resource_size_t start; - pcmcia_common_align(data, res, size, align); + start = pcmcia_common_align(data, res, size, align); for (m = data->map->next; m != data->map; m = m->next) { unsigned long start = m->base; @@ -567,8 +568,7 @@ pcmcia_align(void *align_data, struct resource *res, resource_size_t size, * fit here. */ if (res->start < start) { - res->start = start; - pcmcia_common_align(data, res, size, align); + start = pcmcia_common_align(data, res, size, align); } /* @@ -586,7 +586,9 @@ pcmcia_align(void *align_data, struct resource *res, resource_size_t size, * If we failed to find something suitable, ensure we fail. */ if (m == data->map) - res->start = res->end; + start = res->end; + + return start; } /* diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 7129504e053d..f4195de4eb9d 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -120,8 +120,10 @@ extern void insert_resource_expand_to_fit(struct resource *root, struct resource extern int allocate_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, - void (*alignf)(void *, struct resource *, - resource_size_t, resource_size_t), + resource_size_t (*alignf)(void *, + struct resource *, + resource_size_t, + resource_size_t), void *alignf_data); int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size); diff --git a/include/linux/pci.h b/include/linux/pci.h index 16f48e7506ed..1bd9f52b24b8 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -592,7 +592,8 @@ int __must_check pcibios_enable_device(struct pci_dev *, int mask); char *pcibios_setup(char *str); /* Used only when drivers/pci/setup.c is used */ -void pcibios_align_resource(void *, struct resource *, resource_size_t, +resource_size_t pcibios_align_resource(void *, struct resource *, + resource_size_t, resource_size_t); void pcibios_update_irq(struct pci_dev *, int irq); @@ -827,8 +828,9 @@ int __must_check pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res, resource_size_t size, resource_size_t align, resource_size_t min, unsigned int type_mask, - void (*alignf)(void *, struct resource *, - resource_size_t, resource_size_t), + resource_size_t (*alignf)(void *, struct resource *, + resource_size_t, + resource_size_t), void *alignf_data); void pci_enable_bridges(struct pci_bus *bus); diff --git a/kernel/resource.c b/kernel/resource.c index af96c1e4b54b..e697f20e2288 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -303,8 +303,10 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, static int find_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, - void (*alignf)(void *, struct resource *, - resource_size_t, resource_size_t), + resource_size_t (*alignf)(void *, + struct resource *, + resource_size_t, + resource_size_t), void *alignf_data) { struct resource *this = root->child; @@ -330,7 +332,7 @@ static int find_resource(struct resource *root, struct resource *new, tmp.end = max; tmp.start = ALIGN(tmp.start, align); if (alignf) - alignf(alignf_data, &tmp, size, align); + tmp.start = alignf(alignf_data, &tmp, size, align); if (tmp.start < tmp.end && tmp.end - tmp.start >= size - 1) { new->start = tmp.start; new->end = tmp.start + size - 1; @@ -358,8 +360,10 @@ static int find_resource(struct resource *root, struct resource *new, int allocate_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, - void (*alignf)(void *, struct resource *, - resource_size_t, resource_size_t), + resource_size_t (*alignf)(void *, + struct resource *, + resource_size_t, + resource_size_t), void *alignf_data) { int err; -- cgit v1.2.3 From 3b7a17fcdae532d29dffab9d564a28be08960988 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Fri, 1 Jan 2010 17:40:50 +0100 Subject: resource/PCI: mark struct resource as const Now that we return the new resource start position, there is no need to update "struct resource" inside the align function. Therefore, mark the struct resource as const. Cc: Bjorn Helgaas Cc: Yinghai Lu Signed-off-by: Dominik Brodowski Signed-off-by: Jesse Barnes --- arch/alpha/kernel/pci.c | 2 +- arch/arm/kernel/bios32.c | 2 +- arch/cris/arch-v32/drivers/pci/bios.c | 2 +- arch/frv/mb93090-mb00/pci-frv.c | 2 +- arch/ia64/pci/pci.c | 2 +- arch/mips/pci/pci.c | 2 +- arch/mips/pmc-sierra/yosemite/ht.c | 2 +- arch/mn10300/unit-asb2305/pci-asb2305.c | 2 +- arch/parisc/kernel/pci.c | 2 +- arch/powerpc/kernel/pci-common.c | 2 +- arch/sh/drivers/pci/pci.c | 2 +- arch/sparc/kernel/pci.c | 2 +- arch/sparc/kernel/pcic.c | 2 +- arch/x86/pci/i386.c | 2 +- arch/xtensa/kernel/pci.c | 4 ++-- drivers/pci/bus.c | 2 +- drivers/pcmcia/rsrc_mgr.c | 3 ++- drivers/pcmcia/rsrc_nonstatic.c | 6 +++--- include/linux/ioport.h | 2 +- include/linux/pci.h | 5 +++-- kernel/resource.c | 4 ++-- 21 files changed, 28 insertions(+), 26 deletions(-) (limited to 'kernel') diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c index 5cf111ed851c..c9ab94ee1ca8 100644 --- a/arch/alpha/kernel/pci.c +++ b/arch/alpha/kernel/pci.c @@ -127,7 +127,7 @@ DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, pcibios_fixup_final); #define GB (1024*MB) resource_size_t -pcibios_align_resource(void *data, struct resource *res, +pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c index a7c85f84f06c..bd397e0b663e 100644 --- a/arch/arm/kernel/bios32.c +++ b/arch/arm/kernel/bios32.c @@ -616,7 +616,7 @@ char * __init pcibios_setup(char *str) * but we want to try to avoid allocating at 0x2900-0x2bff * which might be mirrored at 0x0100-0x03ff.. */ -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { resource_size_t start = res->start; diff --git a/arch/cris/arch-v32/drivers/pci/bios.c b/arch/cris/arch-v32/drivers/pci/bios.c index 5811e2f8945c..d4b9c36ddc0f 100644 --- a/arch/cris/arch-v32/drivers/pci/bios.c +++ b/arch/cris/arch-v32/drivers/pci/bios.c @@ -42,7 +42,7 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, } resource_size_t -pcibios_align_resource(void *data, struct resource *res, +pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { resource_size_t start = res->start; diff --git a/arch/frv/mb93090-mb00/pci-frv.c b/arch/frv/mb93090-mb00/pci-frv.c index c947aa43f2a9..1ed15d7fea20 100644 --- a/arch/frv/mb93090-mb00/pci-frv.c +++ b/arch/frv/mb93090-mb00/pci-frv.c @@ -33,7 +33,7 @@ * which might have be mirrored at 0x0100-0x03ff.. */ resource_size_t -pcibios_align_resource(void *data, struct resource *res, +pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { resource_size_t start = res->start; diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c index ef574cd311d1..783c83bb2b49 100644 --- a/arch/ia64/pci/pci.c +++ b/arch/ia64/pci/pci.c @@ -548,7 +548,7 @@ pcibios_disable_device (struct pci_dev *dev) } resource_size_t -pcibios_align_resource (void *data, struct resource *res, +pcibios_align_resource (void *data, const struct resource *res, resource_size_t size, resource_size_t align) { return res->start; diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c index 9085988f7cf3..f87f5e188fa6 100644 --- a/arch/mips/pci/pci.c +++ b/arch/mips/pci/pci.c @@ -50,7 +50,7 @@ static int pci_initialized; * which might have be mirrored at 0x0100-0x03ff.. */ resource_size_t -pcibios_align_resource(void *data, struct resource *res, +pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; diff --git a/arch/mips/pmc-sierra/yosemite/ht.c b/arch/mips/pmc-sierra/yosemite/ht.c index 5e410087b628..fd22597edb64 100644 --- a/arch/mips/pmc-sierra/yosemite/ht.c +++ b/arch/mips/pmc-sierra/yosemite/ht.c @@ -345,7 +345,7 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) return pcibios_enable_resources(dev); } -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; diff --git a/arch/mn10300/unit-asb2305/pci-asb2305.c b/arch/mn10300/unit-asb2305/pci-asb2305.c index b0b3758fba08..d6119b879a98 100644 --- a/arch/mn10300/unit-asb2305/pci-asb2305.c +++ b/arch/mn10300/unit-asb2305/pci-asb2305.c @@ -31,7 +31,7 @@ * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { resource_size_t start = res->start; diff --git a/arch/parisc/kernel/pci.c b/arch/parisc/kernel/pci.c index 4463a31973ba..5179e5e6f8fb 100644 --- a/arch/parisc/kernel/pci.c +++ b/arch/parisc/kernel/pci.c @@ -254,7 +254,7 @@ EXPORT_SYMBOL(pcibios_bus_to_resource); * Since we are just checking candidates, don't use any fields other * than res->start. */ -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t alignment) { resource_size_t mask, align, start = res->start; diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c index d7eebbaf01f1..e640810e813f 100644 --- a/arch/powerpc/kernel/pci-common.c +++ b/arch/powerpc/kernel/pci-common.c @@ -1181,7 +1181,7 @@ static int skip_isa_ioresource_align(struct pci_dev *dev) * but we want to try to avoid allocating at 0x2900-0x2bff * which might have be mirrored at 0x0100-0x03ff.. */ -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c index b36ca825b3d3..96213fd172ce 100644 --- a/arch/sh/drivers/pci/pci.c +++ b/arch/sh/drivers/pci/pci.c @@ -148,7 +148,7 @@ void __devinit pcibios_fixup_bus(struct pci_bus *bus) * addresses to be allocated in the 0x000-0x0ff region * modulo 0x400. */ -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c index d56c1f34689e..37b66c60abe3 100644 --- a/arch/sparc/kernel/pci.c +++ b/arch/sparc/kernel/pci.c @@ -722,7 +722,7 @@ void pcibios_update_irq(struct pci_dev *pdev, int irq) { } -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { return res->start; diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c index 46fda64ff163..75e88c00bca3 100644 --- a/arch/sparc/kernel/pcic.c +++ b/arch/sparc/kernel/pcic.c @@ -768,7 +768,7 @@ char * __devinit pcibios_setup(char *str) return str; } -resource_size_t pcibios_align_resource(void *data, struct resource *res, +resource_size_t pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { return res->start; diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c index 924e40c916d3..5a8fbf8d4cac 100644 --- a/arch/x86/pci/i386.c +++ b/arch/x86/pci/i386.c @@ -61,7 +61,7 @@ skip_isa_ioresource_align(struct pci_dev *dev) { * which might have be mirrored at 0x0100-0x03ff.. */ resource_size_t -pcibios_align_resource(void *data, struct resource *res, +pcibios_align_resource(void *data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c index d7efab03164e..cd1026931203 100644 --- a/arch/xtensa/kernel/pci.c +++ b/arch/xtensa/kernel/pci.c @@ -70,8 +70,8 @@ static int pci_bus_count; * which might have be mirrored at 0x0100-0x03ff.. */ resource_size_t -pcibios_align_resource(void *data, struct resource *res, resource_size_t size, - resource_size_t align) +pcibios_align_resource(void *data, const struct resource *res, + resource_size_t size, resource_size_t align) { struct pci_dev *dev = data; resource_size_t start = res->start; diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index d29d69a37940..a26135bb0ffd 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -37,7 +37,7 @@ pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res, resource_size_t size, resource_size_t align, resource_size_t min, unsigned int type_mask, resource_size_t (*alignf)(void *, - struct resource *, + const struct resource *, resource_size_t, resource_size_t), void *alignf_data) diff --git a/drivers/pcmcia/rsrc_mgr.c b/drivers/pcmcia/rsrc_mgr.c index f92a2dac13a2..f8401a0ef89b 100644 --- a/drivers/pcmcia/rsrc_mgr.c +++ b/drivers/pcmcia/rsrc_mgr.c @@ -114,7 +114,8 @@ struct pcmcia_align_data { unsigned long offset; }; -static resource_size_t pcmcia_align(void *align_data, struct resource *res, +static resource_size_t pcmcia_align(void *align_data, + const struct resource *res, resource_size_t size, resource_size_t align) { struct pcmcia_align_data *data = align_data; diff --git a/drivers/pcmcia/rsrc_nonstatic.c b/drivers/pcmcia/rsrc_nonstatic.c index b65902870e44..45d75dc452f0 100644 --- a/drivers/pcmcia/rsrc_nonstatic.c +++ b/drivers/pcmcia/rsrc_nonstatic.c @@ -534,7 +534,7 @@ struct pcmcia_align_data { }; static resource_size_t -pcmcia_common_align(void *align_data, struct resource *res, +pcmcia_common_align(void *align_data, const struct resource *res, resource_size_t size, resource_size_t align) { struct pcmcia_align_data *data = align_data; @@ -549,8 +549,8 @@ pcmcia_common_align(void *align_data, struct resource *res, } static resource_size_t -pcmcia_align(void *align_data, struct resource *res, resource_size_t size, - resource_size_t align) +pcmcia_align(void *align_data, const struct resource *res, + resource_size_t size, resource_size_t align) { struct pcmcia_align_data *data = align_data; struct resource_map *m; diff --git a/include/linux/ioport.h b/include/linux/ioport.h index f4195de4eb9d..4a811891dbe3 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -121,7 +121,7 @@ extern int allocate_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, resource_size_t (*alignf)(void *, - struct resource *, + const struct resource *, resource_size_t, resource_size_t), void *alignf_data); diff --git a/include/linux/pci.h b/include/linux/pci.h index 1bd9f52b24b8..449d51560fc2 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -592,7 +592,7 @@ int __must_check pcibios_enable_device(struct pci_dev *, int mask); char *pcibios_setup(char *str); /* Used only when drivers/pci/setup.c is used */ -resource_size_t pcibios_align_resource(void *, struct resource *, +resource_size_t pcibios_align_resource(void *, const struct resource *, resource_size_t, resource_size_t); void pcibios_update_irq(struct pci_dev *, int irq); @@ -828,7 +828,8 @@ int __must_check pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res, resource_size_t size, resource_size_t align, resource_size_t min, unsigned int type_mask, - resource_size_t (*alignf)(void *, struct resource *, + resource_size_t (*alignf)(void *, + const struct resource *, resource_size_t, resource_size_t), void *alignf_data); diff --git a/kernel/resource.c b/kernel/resource.c index e697f20e2288..7fd123ad00aa 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -304,7 +304,7 @@ static int find_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, resource_size_t (*alignf)(void *, - struct resource *, + const struct resource *, resource_size_t, resource_size_t), void *alignf_data) @@ -361,7 +361,7 @@ int allocate_resource(struct resource *root, struct resource *new, resource_size_t size, resource_size_t min, resource_size_t max, resource_size_t align, resource_size_t (*alignf)(void *, - struct resource *, + const struct resource *, resource_size_t, resource_size_t), void *alignf_data) -- cgit v1.2.3 From 5eeec0ec931a01e85b3701ce121b7d8a1800ec60 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Tue, 22 Dec 2009 15:02:22 -0800 Subject: resource: add release_child_resources Useful for freeing a portion of the resource tree, e.g. when trying to reallocate resources more efficiently. Signed-off-by: Yinghai Lu Acked-by: Linus Torvalds Signed-off-by: Jesse Barnes --- include/linux/ioport.h | 1 + kernel/resource.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) (limited to 'kernel') diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 4a811891dbe3..dda98410d588 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -112,6 +112,7 @@ extern struct resource iomem_resource; extern int request_resource(struct resource *root, struct resource *new); extern int release_resource(struct resource *new); +void release_child_resources(struct resource *new); extern void reserve_region_with_split(struct resource *root, resource_size_t start, resource_size_t end, const char *name); diff --git a/kernel/resource.c b/kernel/resource.c index 7fd123ad00aa..24e9e60c1459 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -188,6 +188,36 @@ static int __release_resource(struct resource *old) return -EINVAL; } +static void __release_child_resources(struct resource *r) +{ + struct resource *tmp, *p; + resource_size_t size; + + p = r->child; + r->child = NULL; + while (p) { + tmp = p; + p = p->sibling; + + tmp->parent = NULL; + tmp->sibling = NULL; + __release_child_resources(tmp); + + printk(KERN_DEBUG "release child resource %pR\n", tmp); + /* need to restore size, and keep flags */ + size = resource_size(tmp); + tmp->start = 0; + tmp->end = size - 1; + } +} + +void release_child_resources(struct resource *r) +{ + write_lock(&resource_lock); + __release_child_resources(r); + write_unlock(&resource_lock); +} + /** * request_resource - request and reserve an I/O or memory resource * @root: root resource descriptor -- cgit v1.2.3 From 6cbf82148ff286ec22a55be6836c3a5bffc489c1 Mon Sep 17 00:00:00 2001 From: Rafael J. Wysocki Date: Wed, 17 Feb 2010 23:44:58 +0100 Subject: PCI PM: Run-time callbacks for PCI bus type Introduce run-time PM callbacks for the PCI bus type. Make the new callbacks work in analogy with the existing system sleep PM callbacks, so that the drivers already converted to struct dev_pm_ops can use their suspend and resume routines for run-time PM without modifications. Signed-off-by: Rafael J. Wysocki Signed-off-by: Jesse Barnes --- drivers/pci/pci-driver.c | 160 +++++++++++++++++++++++++++++++++++++++-------- drivers/pci/pci.c | 43 +++++++++++-- drivers/pci/pci.h | 1 + include/linux/pci.h | 9 ++- kernel/power/Kconfig | 5 ++ 5 files changed, 184 insertions(+), 34 deletions(-) (limited to 'kernel') diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index e5d47be3c6d7..f9a0aec3abcf 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -17,6 +17,7 @@ #include #include #include +#include #include "pci.h" struct pci_dynid { @@ -404,6 +405,35 @@ static void pci_device_shutdown(struct device *dev) pci_msix_shutdown(pci_dev); } +#ifdef CONFIG_PM_OPS + +/* Auxiliary functions used for system resume and run-time resume. */ + +/** + * pci_restore_standard_config - restore standard config registers of PCI device + * @pci_dev: PCI device to handle + */ +static int pci_restore_standard_config(struct pci_dev *pci_dev) +{ + pci_update_current_state(pci_dev, PCI_UNKNOWN); + + if (pci_dev->current_state != PCI_D0) { + int error = pci_set_power_state(pci_dev, PCI_D0); + if (error) + return error; + } + + return pci_restore_state(pci_dev); +} + +static void pci_pm_default_resume_early(struct pci_dev *pci_dev) +{ + pci_restore_standard_config(pci_dev); + pci_fixup_device(pci_fixup_resume_early, pci_dev); +} + +#endif + #ifdef CONFIG_PM_SLEEP /* @@ -520,29 +550,6 @@ static int pci_legacy_resume(struct device *dev) /* Auxiliary functions used by the new power management framework */ -/** - * pci_restore_standard_config - restore standard config registers of PCI device - * @pci_dev: PCI device to handle - */ -static int pci_restore_standard_config(struct pci_dev *pci_dev) -{ - pci_update_current_state(pci_dev, PCI_UNKNOWN); - - if (pci_dev->current_state != PCI_D0) { - int error = pci_set_power_state(pci_dev, PCI_D0); - if (error) - return error; - } - - return pci_restore_state(pci_dev); -} - -static void pci_pm_default_resume_noirq(struct pci_dev *pci_dev) -{ - pci_restore_standard_config(pci_dev); - pci_fixup_device(pci_fixup_resume_early, pci_dev); -} - static void pci_pm_default_resume(struct pci_dev *pci_dev) { pci_fixup_device(pci_fixup_resume, pci_dev); @@ -581,6 +588,17 @@ static int pci_pm_prepare(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; + /* + * PCI devices suspended at run time need to be resumed at this + * point, because in general it is necessary to reconfigure them for + * system suspend. Namely, if the device is supposed to wake up the + * system from the sleep state, we may need to reconfigure it for this + * purpose. In turn, if the device is not supposed to wake up the + * system from the sleep state, we'll have to prevent it from signaling + * wake-up. + */ + pm_runtime_resume(dev); + if (drv && drv->pm && drv->pm->prepare) error = drv->pm->prepare(dev); @@ -595,6 +613,13 @@ static void pci_pm_complete(struct device *dev) drv->pm->complete(dev); } +#else /* !CONFIG_PM_SLEEP */ + +#define pci_pm_prepare NULL +#define pci_pm_complete NULL + +#endif /* !CONFIG_PM_SLEEP */ + #ifdef CONFIG_SUSPEND static int pci_pm_suspend(struct device *dev) @@ -681,7 +706,7 @@ static int pci_pm_resume_noirq(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; - pci_pm_default_resume_noirq(pci_dev); + pci_pm_default_resume_early(pci_dev); if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume_early(dev); @@ -879,7 +904,7 @@ static int pci_pm_restore_noirq(struct device *dev) struct device_driver *drv = dev->driver; int error = 0; - pci_pm_default_resume_noirq(pci_dev); + pci_pm_default_resume_early(pci_dev); if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume_early(dev); @@ -931,6 +956,84 @@ static int pci_pm_restore(struct device *dev) #endif /* !CONFIG_HIBERNATION */ +#ifdef CONFIG_PM_RUNTIME + +static int pci_pm_runtime_suspend(struct device *dev) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + pci_power_t prev = pci_dev->current_state; + int error; + + if (!pm || !pm->runtime_suspend) + return -ENOSYS; + + error = pm->runtime_suspend(dev); + suspend_report_result(pm->runtime_suspend, error); + if (error) + return error; + + pci_fixup_device(pci_fixup_suspend, pci_dev); + + if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0 + && pci_dev->current_state != PCI_UNKNOWN) { + WARN_ONCE(pci_dev->current_state != prev, + "PCI PM: State of device not saved by %pF\n", + pm->runtime_suspend); + return 0; + } + + if (!pci_dev->state_saved) + pci_save_state(pci_dev); + + pci_finish_runtime_suspend(pci_dev); + + return 0; +} + +static int pci_pm_runtime_resume(struct device *dev) +{ + struct pci_dev *pci_dev = to_pci_dev(dev); + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (!pm || !pm->runtime_resume) + return -ENOSYS; + + pci_pm_default_resume_early(pci_dev); + __pci_enable_wake(pci_dev, PCI_D0, true, false); + pci_fixup_device(pci_fixup_resume, pci_dev); + + return pm->runtime_resume(dev); +} + +static int pci_pm_runtime_idle(struct device *dev) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + + if (!pm) + return -ENOSYS; + + if (pm->runtime_idle) { + int ret = pm->runtime_idle(dev); + if (ret) + return ret; + } + + pm_runtime_suspend(dev); + + return 0; +} + +#else /* !CONFIG_PM_RUNTIME */ + +#define pci_pm_runtime_suspend NULL +#define pci_pm_runtime_resume NULL +#define pci_pm_runtime_idle NULL + +#endif /* !CONFIG_PM_RUNTIME */ + +#ifdef CONFIG_PM_OPS + const struct dev_pm_ops pci_dev_pm_ops = { .prepare = pci_pm_prepare, .complete = pci_pm_complete, @@ -946,15 +1049,18 @@ const struct dev_pm_ops pci_dev_pm_ops = { .thaw_noirq = pci_pm_thaw_noirq, .poweroff_noirq = pci_pm_poweroff_noirq, .restore_noirq = pci_pm_restore_noirq, + .runtime_suspend = pci_pm_runtime_suspend, + .runtime_resume = pci_pm_runtime_resume, + .runtime_idle = pci_pm_runtime_idle, }; #define PCI_PM_OPS_PTR (&pci_dev_pm_ops) -#else /* !CONFIG_PM_SLEEP */ +#else /* !COMFIG_PM_OPS */ #define PCI_PM_OPS_PTR NULL -#endif /* !CONFIG_PM_SLEEP */ +#endif /* !COMFIG_PM_OPS */ /** * __pci_register_driver - register a new pci driver diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index df55a2f351b3..d62a5de81672 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1302,9 +1302,10 @@ void pci_pme_active(struct pci_dev *dev, bool enable) } /** - * pci_enable_wake - enable PCI device as wakeup event source + * __pci_enable_wake - enable PCI device as wakeup event source * @dev: PCI device affected * @state: PCI state from which device will issue wakeup events + * @runtime: True if the events are to be generated at run time * @enable: True to enable event generation; false to disable * * This enables the device as a wakeup event source, or disables it. @@ -1320,11 +1321,12 @@ void pci_pme_active(struct pci_dev *dev, bool enable) * Error code depending on the platform is returned if both the platform and * the native mechanism fail to enable the generation of wake-up events */ -int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable) +int __pci_enable_wake(struct pci_dev *dev, pci_power_t state, + bool runtime, bool enable) { int ret = 0; - if (enable && !device_may_wakeup(&dev->dev)) + if (enable && !runtime && !device_may_wakeup(&dev->dev)) return -EINVAL; /* Don't do the same thing twice in a row for one device. */ @@ -1344,19 +1346,24 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable) pci_pme_active(dev, true); else ret = 1; - error = platform_pci_sleep_wake(dev, true); + error = runtime ? platform_pci_run_wake(dev, true) : + platform_pci_sleep_wake(dev, true); if (ret) ret = error; if (!ret) dev->wakeup_prepared = true; } else { - platform_pci_sleep_wake(dev, false); + if (runtime) + platform_pci_run_wake(dev, false); + else + platform_pci_sleep_wake(dev, false); pci_pme_active(dev, false); dev->wakeup_prepared = false; } return ret; } +EXPORT_SYMBOL(__pci_enable_wake); /** * pci_wake_from_d3 - enable/disable device to wake up from D3_hot or D3_cold @@ -1465,6 +1472,31 @@ int pci_back_from_sleep(struct pci_dev *dev) return pci_set_power_state(dev, PCI_D0); } +/** + * pci_finish_runtime_suspend - Carry out PCI-specific part of runtime suspend. + * @dev: PCI device being suspended. + * + * Prepare @dev to generate wake-up events at run time and put it into a low + * power state. + */ +int pci_finish_runtime_suspend(struct pci_dev *dev) +{ + pci_power_t target_state = pci_target_state(dev); + int error; + + if (target_state == PCI_POWER_ERROR) + return -EIO; + + __pci_enable_wake(dev, target_state, true, pci_dev_run_wake(dev)); + + error = pci_set_power_state(dev, target_state); + + if (error) + __pci_enable_wake(dev, target_state, true, false); + + return error; +} + /** * pci_dev_run_wake - Check if device can generate run-time wake-up events. * @dev: Device to check. @@ -2978,7 +3010,6 @@ EXPORT_SYMBOL(pci_save_state); EXPORT_SYMBOL(pci_restore_state); EXPORT_SYMBOL(pci_pme_capable); EXPORT_SYMBOL(pci_pme_active); -EXPORT_SYMBOL(pci_enable_wake); EXPORT_SYMBOL(pci_wake_from_d3); EXPORT_SYMBOL(pci_target_state); EXPORT_SYMBOL(pci_prepare_to_sleep); diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 286c50821949..4eb10f48d270 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -55,6 +55,7 @@ extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops); extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state); extern void pci_disable_enabled_device(struct pci_dev *dev); extern bool pci_check_pme_status(struct pci_dev *dev); +extern int pci_finish_runtime_suspend(struct pci_dev *dev); extern int __pci_pme_wakeup(struct pci_dev *dev, void *ign); extern void pci_pme_wakeup_bus(struct pci_bus *bus); extern void pci_pm_init(struct pci_dev *dev); diff --git a/include/linux/pci.h b/include/linux/pci.h index 3f787ce78bd1..1a29f9f6b2dc 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -777,13 +777,20 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state); pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state); bool pci_pme_capable(struct pci_dev *dev, pci_power_t state); void pci_pme_active(struct pci_dev *dev, bool enable); -int pci_enable_wake(struct pci_dev *dev, pci_power_t state, bool enable); +int __pci_enable_wake(struct pci_dev *dev, pci_power_t state, + bool runtime, bool enable); int pci_wake_from_d3(struct pci_dev *dev, bool enable); pci_power_t pci_target_state(struct pci_dev *dev); int pci_prepare_to_sleep(struct pci_dev *dev); int pci_back_from_sleep(struct pci_dev *dev); bool pci_dev_run_wake(struct pci_dev *dev); +static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state, + bool enable) +{ + return __pci_enable_wake(dev, state, false, enable); +} + /* For use by arch with custom probe code */ void set_pcie_port_type(struct pci_dev *pdev); void set_pcie_hotplug_bridge(struct pci_dev *pdev); diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 91e09d3b2eb2..4c9cffcf69c7 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -222,3 +222,8 @@ config PM_RUNTIME and the bus type drivers of the buses the devices are on are responsible for the actual handling of the autosuspend requests and wake-up events. + +config PM_OPS + bool + depends on PM_SLEEP || PM_RUNTIME + default y -- cgit v1.2.3 From 701188374b6f1ef9cf7e4dce4a2e69ef4c0012ac Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 22 Feb 2010 12:44:16 -0800 Subject: kernel/sys.c: fix missing rcu protection for sys_getpriority() find_task_by_vpid() is not safe without rcu_read_lock(). 2.6.33-rc7 got RCU protection for sys_setpriority() but missed it for sys_getpriority(). Signed-off-by: Tetsuo Handa Cc: Oleg Nesterov Cc: "Paul E. McKenney" Acked-by: Serge Hallyn Acked-by: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index 26a6b73a6b85..18bde979f346 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -222,6 +222,7 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who) if (which > PRIO_USER || which < PRIO_PROCESS) return -EINVAL; + rcu_read_lock(); read_lock(&tasklist_lock); switch (which) { case PRIO_PROCESS: @@ -267,6 +268,7 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who) } out_unlock: read_unlock(&tasklist_lock); + rcu_read_unlock(); return retval; } -- cgit v1.2.3 From c6a0dd7ec6fb2d4927979ed4dc562fc5c122d826 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 22 Feb 2010 14:51:32 -0800 Subject: ptrace: Fix ptrace_regset() comments and diagnose errors specifically Return -EINVAL for the bad size and for unrecognized NT_* type in ptrace_regset() instead of -EIO. Also update the comments for this ptrace interface with more clarifications. Requested-by: Roland McGrath Requested-by: Oleg Nesterov Signed-off-by: Suresh Siddha LKML-Reference: <20100222225240.397523600@sbs-t61.sc.intel.com> Acked-by: Roland McGrath Signed-off-by: H. Peter Anvin --- include/linux/ptrace.h | 5 +++++ kernel/ptrace.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index dbfa821d5a6e..c5eab89da51e 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -30,6 +30,11 @@ /* * Generic ptrace interface that exports the architecture specific regsets * using the corresponding NT_* types (which are also used in the core dump). + * Please note that the NT_PRSTATUS note type in a core dump contains a full + * 'struct elf_prstatus'. But the user_regset for NT_PRSTATUS contains just the + * elf_gregset_t that is the pr_reg field of 'struct elf_prstatus'. For all the + * other user_regset flavors, the user_regset layout and the ELF core dump note + * payload are exactly the same layout. * * This interface usage is as follows: * struct iovec iov = { buf, len}; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 13b4554d8fbb..42ad8ae729a0 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -537,7 +537,7 @@ static int ptrace_regset(struct task_struct *task, int req, unsigned int type, int regset_no; if (!regset || (kiov->iov_len % regset->size) != 0) - return -EIO; + return -EINVAL; regset_no = regset - view->regsets; kiov->iov_len = min(kiov->iov_len, -- cgit v1.2.3 From 632ee200130899252508c478ad0e808222573fbc Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:04:45 -0800 Subject: rcu: Introduce lockdep-based checking to RCU read-side primitives Inspection is proving insufficient to catch all RCU misuses, which is understandable given that rcu_dereference() might be protected by any of four different flavors of RCU (RCU, RCU-bh, RCU-sched, and SRCU), and might also/instead be protected by any of a number of locking primitives. It is therefore time to enlist the aid of lockdep. This set of patches is inspired by earlier work by Peter Zijlstra and Thomas Gleixner, and takes the following approach: o Set up separate lockdep classes for RCU, RCU-bh, and RCU-sched. o Set up separate lockdep classes for each instance of SRCU. o Create primitives that check for being in an RCU read-side critical section. These return exact answers if lockdep is fully enabled, but if unsure, report being in an RCU read-side critical section. (We want to avoid false positives!) The primitives are: For RCU: rcu_read_lock_held(void) For RCU-bh: rcu_read_lock_bh_held(void) For RCU-sched: rcu_read_lock_sched_held(void) For SRCU: srcu_read_lock_held(struct srcu_struct *sp) o Add rcu_dereference_check(), which takes a second argument in which one places a boolean expression based on the above primitives and/or lockdep_is_held(). o A new kernel configuration parameter, CONFIG_PROVE_RCU, enables rcu_dereference_check(). This depends on CONFIG_PROVE_LOCKING, and should be quite helpful during the transition period while CONFIG_PROVE_RCU-unaware patches are in flight. The existing rcu_dereference() primitive does no checking, but upcoming patches will change that. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-1-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/rcupdate.h | 126 +++++++++++++++++++++++++++++++++++++++++++---- include/linux/srcu.h | 87 +++++++++++++++++++++++++++++++- kernel/rcupdate.c | 10 ++++ kernel/rcutorture.c | 12 ++++- kernel/srcu.c | 50 ++++++++++++------- lib/Kconfig.debug | 12 +++++ lib/debug_locks.c | 1 + 7 files changed, 267 insertions(+), 31 deletions(-) (limited to 'kernel') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 24440f4bf476..e3d37efe2703 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -78,14 +78,120 @@ extern void rcu_init(void); } while (0) #ifdef CONFIG_DEBUG_LOCK_ALLOC + extern struct lockdep_map rcu_lock_map; -# define rcu_read_acquire() \ - lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_) +# define rcu_read_acquire() \ + lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_) # define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_) -#else -# define rcu_read_acquire() do { } while (0) -# define rcu_read_release() do { } while (0) -#endif + +extern struct lockdep_map rcu_bh_lock_map; +# define rcu_read_acquire_bh() \ + lock_acquire(&rcu_bh_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_) +# define rcu_read_release_bh() lock_release(&rcu_bh_lock_map, 1, _THIS_IP_) + +extern struct lockdep_map rcu_sched_lock_map; +# define rcu_read_acquire_sched() \ + lock_acquire(&rcu_sched_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_) +# define rcu_read_release_sched() \ + lock_release(&rcu_sched_lock_map, 1, _THIS_IP_) + +/** + * rcu_read_lock_held - might we be in RCU read-side critical section? + * + * If CONFIG_PROVE_LOCKING is selected and enabled, returns nonzero iff in + * an RCU read-side critical section. In absence of CONFIG_PROVE_LOCKING, + * this assumes we are in an RCU read-side critical section unless it can + * prove otherwise. + */ +static inline int rcu_read_lock_held(void) +{ + if (debug_locks) + return lock_is_held(&rcu_lock_map); + return 1; +} + +/** + * rcu_read_lock_bh_held - might we be in RCU-bh read-side critical section? + * + * If CONFIG_PROVE_LOCKING is selected and enabled, returns nonzero iff in + * an RCU-bh read-side critical section. In absence of CONFIG_PROVE_LOCKING, + * this assumes we are in an RCU-bh read-side critical section unless it can + * prove otherwise. + */ +static inline int rcu_read_lock_bh_held(void) +{ + if (debug_locks) + return lock_is_held(&rcu_bh_lock_map); + return 1; +} + +/** + * rcu_read_lock_sched_held - might we be in RCU-sched read-side critical section? + * + * If CONFIG_PROVE_LOCKING is selected and enabled, returns nonzero iff in an + * RCU-sched read-side critical section. In absence of CONFIG_PROVE_LOCKING, + * this assumes we are in an RCU-sched read-side critical section unless it + * can prove otherwise. Note that disabling of preemption (including + * disabling irqs) counts as an RCU-sched read-side critical section. + */ +static inline int rcu_read_lock_sched_held(void) +{ + int lockdep_opinion = 0; + + if (debug_locks) + lockdep_opinion = lock_is_held(&rcu_sched_lock_map); + return lockdep_opinion || preempt_count() != 0; +} + +#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + +# define rcu_read_acquire() do { } while (0) +# define rcu_read_release() do { } while (0) +# define rcu_read_acquire_bh() do { } while (0) +# define rcu_read_release_bh() do { } while (0) +# define rcu_read_acquire_sched() do { } while (0) +# define rcu_read_release_sched() do { } while (0) + +static inline int rcu_read_lock_held(void) +{ + return 1; +} + +static inline int rcu_read_lock_bh_held(void) +{ + return 1; +} + +static inline int rcu_read_lock_sched_held(void) +{ + return preempt_count() != 0; +} + +#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + +#ifdef CONFIG_PROVE_RCU + +/** + * rcu_dereference_check - rcu_dereference with debug checking + * + * Do an rcu_dereference(), but check that the context is correct. + * For example, rcu_dereference_check(gp, rcu_read_lock_held()) to + * ensure that the rcu_dereference_check() executes within an RCU + * read-side critical section. It is also possible to check for + * locks being held, for example, by using lockdep_is_held(). + */ +#define rcu_dereference_check(p, c) \ + ({ \ + if (debug_locks) \ + WARN_ON_ONCE(!(c)); \ + rcu_dereference(p); \ + }) + +#else /* #ifdef CONFIG_PROVE_RCU */ + +#define rcu_dereference_check(p, c) rcu_dereference(p) + +#endif /* #else #ifdef CONFIG_PROVE_RCU */ /** * rcu_read_lock - mark the beginning of an RCU read-side critical section. @@ -160,7 +266,7 @@ static inline void rcu_read_lock_bh(void) { __rcu_read_lock_bh(); __acquire(RCU_BH); - rcu_read_acquire(); + rcu_read_acquire_bh(); } /* @@ -170,7 +276,7 @@ static inline void rcu_read_lock_bh(void) */ static inline void rcu_read_unlock_bh(void) { - rcu_read_release(); + rcu_read_release_bh(); __release(RCU_BH); __rcu_read_unlock_bh(); } @@ -188,7 +294,7 @@ static inline void rcu_read_lock_sched(void) { preempt_disable(); __acquire(RCU_SCHED); - rcu_read_acquire(); + rcu_read_acquire_sched(); } /* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */ @@ -205,7 +311,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void) */ static inline void rcu_read_unlock_sched(void) { - rcu_read_release(); + rcu_read_release_sched(); __release(RCU_SCHED); preempt_enable(); } diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 4765d97dcafb..adbe1670b366 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -35,6 +35,9 @@ struct srcu_struct { int completed; struct srcu_struct_array *per_cpu_ref; struct mutex mutex; +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map dep_map; +#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ }; #ifndef CONFIG_PREEMPT @@ -43,12 +46,92 @@ struct srcu_struct { #define srcu_barrier() #endif /* #else #ifndef CONFIG_PREEMPT */ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + +int __init_srcu_struct(struct srcu_struct *sp, const char *name, + struct lock_class_key *key); + +#define init_srcu_struct(sp) \ +({ \ + static struct lock_class_key __srcu_key; \ + \ + __init_srcu_struct((sp), #sp, &__srcu_key); \ +}) + +# define srcu_read_acquire(sp) \ + lock_acquire(&(sp)->dep_map, 0, 0, 2, 1, NULL, _THIS_IP_) +# define srcu_read_release(sp) \ + lock_release(&(sp)->dep_map, 1, _THIS_IP_) + +#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + int init_srcu_struct(struct srcu_struct *sp); + +# define srcu_read_acquire(sp) do { } while (0) +# define srcu_read_release(sp) do { } while (0) + +#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + void cleanup_srcu_struct(struct srcu_struct *sp); -int srcu_read_lock(struct srcu_struct *sp) __acquires(sp); -void srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp); +int __srcu_read_lock(struct srcu_struct *sp) __acquires(sp); +void __srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp); void synchronize_srcu(struct srcu_struct *sp); void synchronize_srcu_expedited(struct srcu_struct *sp); long srcu_batches_completed(struct srcu_struct *sp); +#ifdef CONFIG_DEBUG_LOCK_ALLOC + +/** + * srcu_read_lock_held - might we be in SRCU read-side critical section? + * + * If CONFIG_PROVE_LOCKING is selected and enabled, returns nonzero iff in + * an SRCU read-side critical section. In absence of CONFIG_PROVE_LOCKING, + * this assumes we are in an SRCU read-side critical section unless it can + * prove otherwise. + */ +static inline int srcu_read_lock_held(struct srcu_struct *sp) +{ + if (debug_locks) + return lock_is_held(&sp->dep_map); + return 1; +} + +#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + +static inline int srcu_read_lock_held(struct srcu_struct *sp) +{ + return 1; +} + +#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + +/** + * srcu_read_lock - register a new reader for an SRCU-protected structure. + * @sp: srcu_struct in which to register the new reader. + * + * Enter an SRCU read-side critical section. Note that SRCU read-side + * critical sections may be nested. + */ +static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp) +{ + int retval = __srcu_read_lock(sp); + + srcu_read_acquire(sp); + return retval; +} + +/** + * srcu_read_unlock - unregister a old reader from an SRCU-protected structure. + * @sp: srcu_struct in which to unregister the old reader. + * @idx: return value from corresponding srcu_read_lock(). + * + * Exit an SRCU read-side critical section. + */ +static inline void srcu_read_unlock(struct srcu_struct *sp, int idx) + __releases(sp) +{ + srcu_read_release(sp); + __srcu_read_unlock(sp, idx); +} + #endif diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 9b7fd4723878..033cb55c26df 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -50,6 +50,16 @@ static struct lock_class_key rcu_lock_key; struct lockdep_map rcu_lock_map = STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key); EXPORT_SYMBOL_GPL(rcu_lock_map); + +static struct lock_class_key rcu_bh_lock_key; +struct lockdep_map rcu_bh_lock_map = + STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_bh", &rcu_bh_lock_key); +EXPORT_SYMBOL_GPL(rcu_bh_lock_map); + +static struct lock_class_key rcu_sched_lock_key; +struct lockdep_map rcu_sched_lock_map = + STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_sched", &rcu_sched_lock_key); +EXPORT_SYMBOL_GPL(rcu_sched_lock_map); #endif /* diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index adda92bfafac..5f43f30fcd1d 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -796,7 +796,11 @@ static void rcu_torture_timer(unsigned long unused) idx = cur_ops->readlock(); completed = cur_ops->completed(); - p = rcu_dereference(rcu_torture_current); + p = rcu_dereference_check(rcu_torture_current, + rcu_read_lock_held() || + rcu_read_lock_bh_held() || + rcu_read_lock_sched_held() || + srcu_read_lock_held(&srcu_ctl)); if (p == NULL) { /* Leave because rcu_torture_writer is not yet underway */ cur_ops->readunlock(idx); @@ -853,7 +857,11 @@ rcu_torture_reader(void *arg) } idx = cur_ops->readlock(); completed = cur_ops->completed(); - p = rcu_dereference(rcu_torture_current); + p = rcu_dereference_check(rcu_torture_current, + rcu_read_lock_held() || + rcu_read_lock_bh_held() || + rcu_read_lock_sched_held() || + srcu_read_lock_held(&srcu_ctl)); if (p == NULL) { /* Wait for rcu_torture_writer to get underway */ cur_ops->readunlock(idx); diff --git a/kernel/srcu.c b/kernel/srcu.c index 31b275b9c112..bde4295774c8 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -34,6 +34,30 @@ #include #include +static int init_srcu_struct_fields(struct srcu_struct *sp) +{ + sp->completed = 0; + mutex_init(&sp->mutex); + sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array); + return sp->per_cpu_ref ? 0 : -ENOMEM; +} + +#ifdef CONFIG_DEBUG_LOCK_ALLOC + +int __init_srcu_struct(struct srcu_struct *sp, const char *name, + struct lock_class_key *key) +{ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + /* Don't re-initialize a lock while it is held. */ + debug_check_no_locks_freed((void *)sp, sizeof(*sp)); + lockdep_init_map(&sp->dep_map, name, key, 0); +#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + return init_srcu_struct_fields(sp); +} +EXPORT_SYMBOL_GPL(__init_srcu_struct); + +#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + /** * init_srcu_struct - initialize a sleep-RCU structure * @sp: structure to initialize. @@ -44,13 +68,12 @@ */ int init_srcu_struct(struct srcu_struct *sp) { - sp->completed = 0; - mutex_init(&sp->mutex); - sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array); - return (sp->per_cpu_ref ? 0 : -ENOMEM); + return init_srcu_struct_fields(sp); } EXPORT_SYMBOL_GPL(init_srcu_struct); +#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ + /* * srcu_readers_active_idx -- returns approximate number of readers * active on the specified rank of per-CPU counters. @@ -100,15 +123,12 @@ void cleanup_srcu_struct(struct srcu_struct *sp) } EXPORT_SYMBOL_GPL(cleanup_srcu_struct); -/** - * srcu_read_lock - register a new reader for an SRCU-protected structure. - * @sp: srcu_struct in which to register the new reader. - * +/* * Counts the new reader in the appropriate per-CPU element of the * srcu_struct. Must be called from process context. * Returns an index that must be passed to the matching srcu_read_unlock(). */ -int srcu_read_lock(struct srcu_struct *sp) +int __srcu_read_lock(struct srcu_struct *sp) { int idx; @@ -120,26 +140,22 @@ int srcu_read_lock(struct srcu_struct *sp) preempt_enable(); return idx; } -EXPORT_SYMBOL_GPL(srcu_read_lock); +EXPORT_SYMBOL_GPL(__srcu_read_lock); -/** - * srcu_read_unlock - unregister a old reader from an SRCU-protected structure. - * @sp: srcu_struct in which to unregister the old reader. - * @idx: return value from corresponding srcu_read_lock(). - * +/* * Removes the count for the old reader from the appropriate per-CPU * element of the srcu_struct. Note that this may well be a different * CPU than that which was incremented by the corresponding srcu_read_lock(). * Must be called from process context. */ -void srcu_read_unlock(struct srcu_struct *sp, int idx) +void __srcu_read_unlock(struct srcu_struct *sp, int idx) { preempt_disable(); srcu_barrier(); /* ensure compiler won't misorder critical section. */ per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--; preempt_enable(); } -EXPORT_SYMBOL_GPL(srcu_read_unlock); +EXPORT_SYMBOL_GPL(__srcu_read_unlock); /* * Helper function for synchronize_srcu() and synchronize_srcu_expedited(). diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 6bf97d176326..6af20a8a0a54 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -499,6 +499,18 @@ config PROVE_LOCKING For more details, see Documentation/lockdep-design.txt. +config PROVE_RCU + bool "RCU debugging: prove RCU correctness" + depends on PROVE_LOCKING + default n + help + This feature enables lockdep extensions that check for correct + use of RCU APIs. This is currently under development. Say Y + if you want to debug RCU usage or help work on the PROVE_RCU + feature. + + Say N if you are unsure. + config LOCKDEP bool depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT diff --git a/lib/debug_locks.c b/lib/debug_locks.c index bc3b11731b9c..5bf0020b9248 100644 --- a/lib/debug_locks.c +++ b/lib/debug_locks.c @@ -23,6 +23,7 @@ * shut up after that. */ int debug_locks = 1; +EXPORT_SYMBOL_GPL(debug_locks); /* * The locking-testsuite uses to get a -- cgit v1.2.3 From 0632eb3d7563d6a76d49a3860b6352d800c92854 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:04:47 -0800 Subject: rcu: Integrate rcu_dereference_check() message into lockdep Make rcu_dereference_check() print the list of held locks in addition to the stack dump to ease debugging. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-3-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 4 ++++ include/linux/rcupdate.h | 4 ++-- kernel/lockdep.c | 18 ++++++++++++++++++ 3 files changed, 24 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 9ccf0e286b2a..10206a87da19 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -534,4 +534,8 @@ do { \ # define might_lock_read(lock) do { } while (0) #endif +#ifdef CONFIG_PROVE_RCU +extern void lockdep_rcu_dereference(const char *file, const int line); +#endif + #endif /* __LINUX_LOCKDEP_H */ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 839d296a7ac0..1a4de31bd7b4 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -182,8 +182,8 @@ static inline int rcu_read_lock_sched_held(void) */ #define rcu_dereference_check(p, c) \ ({ \ - if (debug_locks) \ - WARN_ON_ONCE(!(c)); \ + if (debug_locks && !(c)) \ + lockdep_rcu_dereference(__FILE__, __LINE__); \ rcu_dereference_raw(p); \ }) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index c62ec14609b9..672c436946ce 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3809,3 +3809,21 @@ void lockdep_sys_exit(void) lockdep_print_held_locks(curr); } } + +void lockdep_rcu_dereference(const char *file, const int line) +{ + struct task_struct *curr = current; + + if (!debug_locks_off()) + return; + printk("\n==============================================\n"); + printk( "[ BUG: Unsafe rcu_dereference_check() usage! ]\n"); + printk( "----------------------------------------------\n"); + printk("%s:%d invoked rcu_dereference_check() without protection!\n", + file, line); + printk("\nother info that might help us debug this:\n\n"); + lockdep_print_held_locks(curr); + printk("\nstack backtrace:\n"); + dump_stack(); +} +EXPORT_SYMBOL_GPL(lockdep_rcu_dereference); -- cgit v1.2.3 From d11c563dd20ff35da5652c3e1c989d9e10e1d6d0 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:04:50 -0800 Subject: sched: Use lockdep-based checking on rcu_dereference() Update the rcu_dereference() usages to take advantage of the new lockdep-based checking. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com> [ -v2: fix allmodconfig missing symbol export build failure on x86 ] Signed-off-by: Ingo Molnar --- include/linux/cgroup.h | 5 ++++- include/linux/cred.h | 2 +- init/main.c | 2 ++ kernel/cgroup.c | 14 ++++++++++++++ kernel/exit.c | 14 +++++++++++--- kernel/fork.c | 1 + kernel/notifier.c | 6 +++--- kernel/pid.c | 2 +- kernel/sched.c | 11 ++++++++--- 9 files changed, 45 insertions(+), 12 deletions(-) (limited to 'kernel') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 0008dee66514..c9bbcb2a75ae 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -28,6 +28,7 @@ struct css_id; extern int cgroup_init_early(void); extern int cgroup_init(void); extern void cgroup_lock(void); +extern int cgroup_lock_is_held(void); extern bool cgroup_lock_live_group(struct cgroup *cgrp); extern void cgroup_unlock(void); extern void cgroup_fork(struct task_struct *p); @@ -486,7 +487,9 @@ static inline struct cgroup_subsys_state *cgroup_subsys_state( static inline struct cgroup_subsys_state *task_subsys_state( struct task_struct *task, int subsys_id) { - return rcu_dereference(task->cgroups->subsys[subsys_id]); + return rcu_dereference_check(task->cgroups->subsys[subsys_id], + rcu_read_lock_held() || + cgroup_lock_is_held()); } static inline struct cgroup* task_cgroup(struct task_struct *task, diff --git a/include/linux/cred.h b/include/linux/cred.h index 4e3387a89cb9..4db09f89b637 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -280,7 +280,7 @@ static inline void put_cred(const struct cred *_cred) * task or by holding tasklist_lock to prevent it from being unlinked. */ #define __task_cred(task) \ - ((const struct cred *)(rcu_dereference((task)->real_cred))) + ((const struct cred *)(rcu_dereference_check((task)->real_cred, rcu_read_lock_held() || lockdep_is_held(&tasklist_lock)))) /** * get_task_cred - Get another task's objective credentials diff --git a/init/main.c b/init/main.c index 4cb47a159f02..c75dcd6eef09 100644 --- a/init/main.c +++ b/init/main.c @@ -416,7 +416,9 @@ static noinline void __init_refok rest_init(void) kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND); numa_default_policy(); pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES); + rcu_read_lock(); kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns); + rcu_read_unlock(); unlock_kernel(); /* diff --git a/kernel/cgroup.c b/kernel/cgroup.c index aa3bee566446..b1a0f5a528fe 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -166,6 +166,20 @@ static DEFINE_SPINLOCK(hierarchy_id_lock); */ static int need_forkexit_callback __read_mostly; +#ifdef CONFIG_PROVE_LOCKING +int cgroup_lock_is_held(void) +{ + return lockdep_is_held(&cgroup_mutex); +} +#else /* #ifdef CONFIG_PROVE_LOCKING */ +int cgroup_lock_is_held(void) +{ + return mutex_is_locked(&cgroup_mutex); +} +#endif /* #else #ifdef CONFIG_PROVE_LOCKING */ + +EXPORT_SYMBOL_GPL(cgroup_lock_is_held); + /* convenient tests for these bits */ inline int cgroup_is_removed(const struct cgroup *cgrp) { diff --git a/kernel/exit.c b/kernel/exit.c index 546774a31a66..45ed043b8bf5 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -85,7 +85,9 @@ static void __exit_signal(struct task_struct *tsk) BUG_ON(!sig); BUG_ON(!atomic_read(&sig->count)); - sighand = rcu_dereference(tsk->sighand); + sighand = rcu_dereference_check(tsk->sighand, + rcu_read_lock_held() || + lockdep_is_held(&tasklist_lock)); spin_lock(&sighand->siglock); posix_cpu_timers_exit(tsk); @@ -170,8 +172,10 @@ void release_task(struct task_struct * p) repeat: tracehook_prepare_release_task(p); /* don't need to get the RCU readlock here - the process is dead and - * can't be modifying its own credentials */ + * can't be modifying its own credentials. But shut RCU-lockdep up */ + rcu_read_lock(); atomic_dec(&__task_cred(p)->user->processes); + rcu_read_unlock(); proc_flush_task(p); @@ -473,9 +477,11 @@ static void close_files(struct files_struct * files) /* * It is safe to dereference the fd table without RCU or * ->file_lock because this is the last reference to the - * files structure. + * files structure. But use RCU to shut RCU-lockdep up. */ + rcu_read_lock(); fdt = files_fdtable(files); + rcu_read_unlock(); for (;;) { unsigned long set; i = j * __NFDBITS; @@ -521,10 +527,12 @@ void put_files_struct(struct files_struct *files) * at the end of the RCU grace period. Otherwise, * you can free files immediately. */ + rcu_read_lock(); fdt = files_fdtable(files); if (fdt != &files->fdtab) kmem_cache_free(files_cachep, files); free_fdtable(fdt); + rcu_read_unlock(); } } diff --git a/kernel/fork.c b/kernel/fork.c index f88bd984df35..17bbf093356d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -86,6 +86,7 @@ int max_threads; /* tunable limit on nr_threads */ DEFINE_PER_CPU(unsigned long, process_counts) = 0; __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ +EXPORT_SYMBOL_GPL(tasklist_lock); int nr_processes(void) { diff --git a/kernel/notifier.c b/kernel/notifier.c index acd24e7643eb..2488ba7eb568 100644 --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -78,10 +78,10 @@ static int __kprobes notifier_call_chain(struct notifier_block **nl, int ret = NOTIFY_DONE; struct notifier_block *nb, *next_nb; - nb = rcu_dereference(*nl); + nb = rcu_dereference_raw(*nl); while (nb && nr_to_call) { - next_nb = rcu_dereference(nb->next); + next_nb = rcu_dereference_raw(nb->next); #ifdef CONFIG_DEBUG_NOTIFIERS if (unlikely(!func_ptr_is_kernel_text(nb->notifier_call))) { @@ -309,7 +309,7 @@ int __blocking_notifier_call_chain(struct blocking_notifier_head *nh, * racy then it does not matter what the result of the test * is, we re-check the list after having taken the lock anyway: */ - if (rcu_dereference(nh->head)) { + if (rcu_dereference_raw(nh->head)) { down_read(&nh->rwsem); ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); diff --git a/kernel/pid.c b/kernel/pid.c index 2e17c9c92cbe..b08e697cd83f 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -367,7 +367,7 @@ struct task_struct *pid_task(struct pid *pid, enum pid_type type) struct task_struct *result = NULL; if (pid) { struct hlist_node *first; - first = rcu_dereference(pid->tasks[type].first); + first = rcu_dereference_check(pid->tasks[type].first, rcu_read_lock_held() || lockdep_is_held(&tasklist_lock)); if (first) result = hlist_entry(first, struct task_struct, pids[(type)].node); } diff --git a/kernel/sched.c b/kernel/sched.c index 3a8fb30a91b1..70ae68680d4c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -645,6 +645,11 @@ static inline int cpu_of(struct rq *rq) #endif } +#define for_each_domain_rd(p) \ + rcu_dereference_check((p), \ + rcu_read_lock_sched_held() || \ + lockdep_is_held(&sched_domains_mutex)) + /* * The domain tree (rq->sd) is protected by RCU's quiescent state transition. * See detach_destroy_domains: synchronize_sched for details. @@ -653,7 +658,7 @@ static inline int cpu_of(struct rq *rq) * preempt-disabled sections. */ #define for_each_domain(cpu, __sd) \ - for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) + for (__sd = for_each_domain_rd(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) #define this_rq() (&__get_cpu_var(runqueues)) @@ -1531,7 +1536,7 @@ static unsigned long target_load(int cpu, int type) static struct sched_group *group_of(int cpu) { - struct sched_domain *sd = rcu_dereference(cpu_rq(cpu)->sd); + struct sched_domain *sd = rcu_dereference_sched(cpu_rq(cpu)->sd); if (!sd) return NULL; @@ -4888,7 +4893,7 @@ static void run_rebalance_domains(struct softirq_action *h) static inline int on_null_domain(int cpu) { - return !rcu_dereference(cpu_rq(cpu)->sd); + return !rcu_dereference_sched(cpu_rq(cpu)->sd); } /* -- cgit v1.2.3 From 497f0ab39cd25bed317b29482c147c967f7ecd1f Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:04:51 -0800 Subject: sched: Better name for for_each_domain_rd As suggested by Peter Ziljstra, make better choice of name for for_each_domain_rd(), containing "rcu_dereference", given that it is but a wrapper for rcu_dereference_check(). The name rcu_dereference_check_sched_domain() does that and provides a separate per-subsystem name space. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-7-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 70ae68680d4c..3218f5213717 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -645,7 +645,7 @@ static inline int cpu_of(struct rq *rq) #endif } -#define for_each_domain_rd(p) \ +#define rcu_dereference_check_sched_domain(p) \ rcu_dereference_check((p), \ rcu_read_lock_sched_held() || \ lockdep_is_held(&sched_domains_mutex)) @@ -658,7 +658,7 @@ static inline int cpu_of(struct rq *rq) * preempt-disabled sections. */ #define for_each_domain(cpu, __sd) \ - for (__sd = for_each_domain_rd(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) + for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) #define this_rq() (&__get_cpu_var(runqueues)) -- cgit v1.2.3 From 8bd93a2c5d4cab2ae17d06350daa7dbf546a4634 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:04:59 -0800 Subject: rcu: Accelerate grace period if last non-dynticked CPU Currently, rcu_needs_cpu() simply checks whether the current CPU has an outstanding RCU callback, which means that the last CPU to go into dyntick-idle mode might wait a few ticks for the relevant grace periods to complete. However, if all the other CPUs are in dyntick-idle mode, and if this CPU is in a quiescent state (which it is for RCU-bh and RCU-sched any time that we are considering going into dyntick-idle mode), then the grace period is instantly complete. This patch therefore repeatedly invokes the RCU grace-period machinery in order to force any needed grace periods to complete quickly. It does so a limited number of times in order to prevent starvation by an RCU callback function that might pass itself to call_rcu(). However, if any CPU other than the current one is not in dyntick-idle mode, fall back to simply checking (with fix to bug noted by Lai Jiangshan). Also, take advantage of last grace-period forcing, the opportunity to do so noted by Steve Rostedt. And apply simplified #ifdef condition suggested by Frederic Weisbecker. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-15-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/cpumask.h | 14 ++++++++++ init/Kconfig | 16 ++++++++++++ kernel/rcutree.c | 5 ++-- kernel/rcutree_plugin.h | 69 +++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 101 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index d77b54733c5b..dbcee7647d9a 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -143,6 +143,8 @@ static inline unsigned int cpumask_any_but(const struct cpumask *mask, #define for_each_cpu(cpu, mask) \ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) +#define for_each_cpu_not(cpu, mask) \ + for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask) #define for_each_cpu_and(cpu, mask, and) \ for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask, (void)and) #else @@ -202,6 +204,18 @@ int cpumask_any_but(const struct cpumask *mask, unsigned int cpu); (cpu) = cpumask_next((cpu), (mask)), \ (cpu) < nr_cpu_ids;) +/** + * for_each_cpu_not - iterate over every cpu in a complemented mask + * @cpu: the (optionally unsigned) integer iterator + * @mask: the cpumask pointer + * + * After the loop, cpu is >= nr_cpu_ids. + */ +#define for_each_cpu_not(cpu, mask) \ + for ((cpu) = -1; \ + (cpu) = cpumask_next_zero((cpu), (mask)), \ + (cpu) < nr_cpu_ids;) + /** * for_each_cpu_and - iterate over every cpu in both masks * @cpu: the (optionally unsigned) integer iterator diff --git a/init/Kconfig b/init/Kconfig index d95ca7cd5d45..42bf914b325a 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -396,6 +396,22 @@ config RCU_FANOUT_EXACT Say N if unsure. +config RCU_FAST_NO_HZ + bool "Accelerate last non-dyntick-idle CPU's grace periods" + depends on TREE_RCU && NO_HZ && SMP + default n + help + This option causes RCU to attempt to accelerate grace periods + in order to allow the final CPU to enter dynticks-idle state + more quickly. On the other hand, this option increases the + overhead of the dynticks-idle checking, particularly on systems + with large numbers of CPUs. + + Say Y if energy efficiency is critically important, particularly + if you have relatively few CPUs. + + Say N if you are unsure. + config TREE_RCU_TRACE def_bool RCU_TRACE && ( TREE_RCU || TREE_PREEMPT_RCU ) select DEBUG_FS diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 099a255ede4c..29d88c08d875 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1550,10 +1550,9 @@ static int rcu_pending(int cpu) /* * Check to see if any future RCU-related work will need to be done * by the current CPU, even if none need be done immediately, returning - * 1 if so. This function is part of the RCU implementation; it is -not- - * an exported member of the RCU API. + * 1 if so. */ -int rcu_needs_cpu(int cpu) +static int rcu_needs_cpu_quick_check(int cpu) { /* RCU callbacks either ready or pending? */ return per_cpu(rcu_sched_data, cpu).nxtlist || diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index e77cdf321e13..a82566696b0b 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -906,3 +906,72 @@ static void __init __rcu_init_preempt(void) } #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ + +#if !defined(CONFIG_RCU_FAST_NO_HZ) + +/* + * Check to see if any future RCU-related work will need to be done + * by the current CPU, even if none need be done immediately, returning + * 1 if so. This function is part of the RCU implementation; it is -not- + * an exported member of the RCU API. + * + * Because we have preemptible RCU, just check whether this CPU needs + * any flavor of RCU. Do not chew up lots of CPU cycles with preemption + * disabled in a most-likely vain attempt to cause RCU not to need this CPU. + */ +int rcu_needs_cpu(int cpu) +{ + return rcu_needs_cpu_quick_check(cpu); +} + +#else /* #if !defined(CONFIG_RCU_FAST_NO_HZ) */ + +#define RCU_NEEDS_CPU_FLUSHES 5 + +/* + * Check to see if any future RCU-related work will need to be done + * by the current CPU, even if none need be done immediately, returning + * 1 if so. This function is part of the RCU implementation; it is -not- + * an exported member of the RCU API. + * + * Because we are not supporting preemptible RCU, attempt to accelerate + * any current grace periods so that RCU no longer needs this CPU, but + * only if all other CPUs are already in dynticks-idle mode. This will + * allow the CPU cores to be powered down immediately, as opposed to after + * waiting many milliseconds for grace periods to elapse. + */ +int rcu_needs_cpu(int cpu) +{ + int c = 1; + int i; + int thatcpu; + + /* Don't bother unless we are the last non-dyntick-idle CPU. */ + for_each_cpu_not(thatcpu, nohz_cpu_mask) + if (thatcpu != cpu) + return rcu_needs_cpu_quick_check(cpu); + + /* Try to push remaining RCU-sched and RCU-bh callbacks through. */ + for (i = 0; i < RCU_NEEDS_CPU_FLUSHES && c; i++) { + c = 0; + if (per_cpu(rcu_sched_data, cpu).nxtlist) { + rcu_sched_qs(cpu); + force_quiescent_state(&rcu_sched_state, 0); + __rcu_process_callbacks(&rcu_sched_state, + &per_cpu(rcu_sched_data, cpu)); + c = !!per_cpu(rcu_sched_data, cpu).nxtlist; + } + if (per_cpu(rcu_bh_data, cpu).nxtlist) { + rcu_bh_qs(cpu); + force_quiescent_state(&rcu_bh_state, 0); + __rcu_process_callbacks(&rcu_bh_state, + &per_cpu(rcu_bh_data, cpu)); + c = !!per_cpu(rcu_bh_data, cpu).nxtlist; + } + } + + /* If RCU callbacks are still pending, RCU still needs this CPU. */ + return c; +} + +#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */ -- cgit v1.2.3 From 20133cfce7d0bbdcc0c398301030c091f5675c88 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:05:01 -0800 Subject: rcu: Stop overflowing signed integers The C standard does not specify the result of an operation that overflows a signed integer, so such operations need to be avoided. This patch changes the type of several fields from "long" to "unsigned long" and adjusts operations as needed. ULONG_CMP_GE() and ULONG_CMP_LT() macros are introduced to do the modular comparisons that are appropriate given that overflow is an expected event. Acked-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-17-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 11 +++++------ kernel/rcutree.h | 33 ++++++++++++++++++--------------- kernel/rcutree_trace.c | 14 +++++++------- 3 files changed, 30 insertions(+), 28 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 29d88c08d875..dd0d31dffcdc 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -500,7 +500,7 @@ static void print_cpu_stall(struct rcu_state *rsp) trigger_all_cpu_backtrace(); spin_lock_irqsave(&rnp->lock, flags); - if ((long)(jiffies - rsp->jiffies_stall) >= 0) + if (ULONG_CMP_GE(jiffies, rsp->jiffies_stall)) rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK; spin_unlock_irqrestore(&rnp->lock, flags); @@ -1216,8 +1216,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) rsp->n_force_qs_lh++; /* Inexact, can lose counts. Tough! */ return; /* Someone else is already on the job. */ } - if (relaxed && - (long)(rsp->jiffies_force_qs - jiffies) >= 0) + if (relaxed && ULONG_CMP_GE(rsp->jiffies_force_qs, jiffies)) goto unlock_fqs_ret; /* no emergency and done recently. */ rsp->n_force_qs++; spin_lock(&rnp->lock); /* irqs already disabled */ @@ -1295,7 +1294,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) * If an RCU GP has gone long enough, go check for dyntick * idle CPUs and, if needed, send resched IPIs. */ - if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0) + if (ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) force_quiescent_state(rsp, 1); /* @@ -1392,7 +1391,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), force_quiescent_state(rsp, 0); rdp->n_force_qs_snap = rsp->n_force_qs; rdp->qlen_last_fqs_check = rdp->qlen; - } else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0) + } else if (ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) force_quiescent_state(rsp, 1); local_irq_restore(flags); } @@ -1525,7 +1524,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) /* Has an RCU GP gone long enough to send resched IPIs &c? */ if (rcu_gp_in_progress(rsp) && - ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)) { + ULONG_CMP_LT(ACCESS_ONCE(rsp->jiffies_force_qs), jiffies)) { rdp->n_rp_need_fqs++; return 1; } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index d9d032abd665..7495fed49c30 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -92,10 +92,10 @@ struct rcu_dynticks { struct rcu_node { spinlock_t lock; /* Root rcu_node's lock protects some */ /* rcu_state fields as well as following. */ - long gpnum; /* Current grace period for this node. */ + unsigned long gpnum; /* Current grace period for this node. */ /* This will either be equal to or one */ /* behind the root rcu_node's gpnum. */ - long completed; /* Last grace period completed for this node. */ + unsigned long completed; /* Last GP completed for this node. */ /* This will either be equal to or one */ /* behind the root rcu_node's gpnum. */ unsigned long qsmask; /* CPUs or groups that need to switch in */ @@ -161,11 +161,11 @@ struct rcu_node { /* Per-CPU data for read-copy update. */ struct rcu_data { /* 1) quiescent-state and grace-period handling : */ - long completed; /* Track rsp->completed gp number */ + unsigned long completed; /* Track rsp->completed gp number */ /* in order to detect GP end. */ - long gpnum; /* Highest gp number that this CPU */ + unsigned long gpnum; /* Highest gp number that this CPU */ /* is aware of having started. */ - long passed_quiesc_completed; + unsigned long passed_quiesc_completed; /* Value of completed at time of qs. */ bool passed_quiesc; /* User-mode/idle loop etc. */ bool qs_pending; /* Core waits for quiesc state. */ @@ -221,14 +221,14 @@ struct rcu_data { unsigned long resched_ipi; /* Sent a resched IPI. */ /* 5) __rcu_pending() statistics. */ - long n_rcu_pending; /* rcu_pending() calls since boot. */ - long n_rp_qs_pending; - long n_rp_cb_ready; - long n_rp_cpu_needs_gp; - long n_rp_gp_completed; - long n_rp_gp_started; - long n_rp_need_fqs; - long n_rp_need_nothing; + unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ + unsigned long n_rp_qs_pending; + unsigned long n_rp_cb_ready; + unsigned long n_rp_cpu_needs_gp; + unsigned long n_rp_gp_completed; + unsigned long n_rp_gp_started; + unsigned long n_rp_need_fqs; + unsigned long n_rp_need_nothing; int cpu; }; @@ -255,6 +255,9 @@ struct rcu_data { #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ +#define ULONG_CMP_GE(a, b) (ULONG_MAX / 2 >= (a) - (b)) +#define ULONG_CMP_LT(a, b) (ULONG_MAX / 2 < (a) - (b)) + /* * RCU global state, including node hierarchy. This hierarchy is * represented in "heap" form in a dense array. The root (first level) @@ -283,8 +286,8 @@ struct rcu_state { /* period because */ /* force_quiescent_state() */ /* was running. */ - long gpnum; /* Current gp number. */ - long completed; /* # of last completed gp. */ + unsigned long gpnum; /* Current gp number. */ + unsigned long completed; /* # of last completed gp. */ /* End of fields guarded by root rcu_node's lock. */ diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 9d2c88423b31..d45db2e35d27 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -50,7 +50,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) { if (!rdp->beenonline) return; - seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d", + seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d", rdp->cpu, cpu_is_offline(rdp->cpu) ? '!' : ' ', rdp->completed, rdp->gpnum, @@ -105,7 +105,7 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp) { if (!rdp->beenonline) return; - seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d", + seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d", rdp->cpu, cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"", rdp->completed, rdp->gpnum, @@ -155,13 +155,13 @@ static const struct file_operations rcudata_csv_fops = { static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) { - long gpnum; + unsigned long gpnum; int level = 0; int phase; struct rcu_node *rnp; gpnum = rsp->gpnum; - seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x " + seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x " "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n", rsp->completed, gpnum, rsp->signaled, (long)(rsp->jiffies_force_qs - jiffies), @@ -215,12 +215,12 @@ static const struct file_operations rcuhier_fops = { static int show_rcugp(struct seq_file *m, void *unused) { #ifdef CONFIG_TREE_PREEMPT_RCU - seq_printf(m, "rcu_preempt: completed=%ld gpnum=%ld\n", + seq_printf(m, "rcu_preempt: completed=%ld gpnum=%lu\n", rcu_preempt_state.completed, rcu_preempt_state.gpnum); #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ - seq_printf(m, "rcu_sched: completed=%ld gpnum=%ld\n", + seq_printf(m, "rcu_sched: completed=%ld gpnum=%lu\n", rcu_sched_state.completed, rcu_sched_state.gpnum); - seq_printf(m, "rcu_bh: completed=%ld gpnum=%ld\n", + seq_printf(m, "rcu_bh: completed=%ld gpnum=%lu\n", rcu_bh_state.completed, rcu_bh_state.gpnum); return 0; } -- cgit v1.2.3 From 1304afb225288a2e250d6a7495462c28e5509cbb Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:05:02 -0800 Subject: rcu: Convert to raw_spinlocks The spinlocks in rcutree need to be real spinlocks in preempt-rt. Convert them to raw_spinlocks. Signed-off-by: Thomas Gleixner Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-18-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 132 ++++++++++++++++++++++++------------------------ kernel/rcutree.h | 6 +-- kernel/rcutree_plugin.h | 46 ++++++++--------- 3 files changed, 92 insertions(+), 92 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index dd0d31dffcdc..65a807b4f58c 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -66,11 +66,11 @@ static struct lock_class_key rcu_node_class[NUM_RCU_LVLS]; .signaled = RCU_GP_IDLE, \ .gpnum = -300, \ .completed = -300, \ - .onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \ + .onofflock = __RAW_SPIN_LOCK_UNLOCKED(&name.onofflock), \ .orphan_cbs_list = NULL, \ .orphan_cbs_tail = &name.orphan_cbs_list, \ .orphan_qlen = 0, \ - .fqslock = __SPIN_LOCK_UNLOCKED(&name.fqslock), \ + .fqslock = __RAW_SPIN_LOCK_UNLOCKED(&name.fqslock), \ .n_force_qs = 0, \ .n_force_qs_ngp = 0, \ } @@ -457,10 +457,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp) /* Only let one CPU complain about others per time interval. */ - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); delta = jiffies - rsp->jiffies_stall; if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK; @@ -470,7 +470,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp) * due to CPU offlining. */ rcu_print_task_stall(rnp); - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); /* OK, time to rat on our buddy... */ @@ -499,11 +499,11 @@ static void print_cpu_stall(struct rcu_state *rsp) smp_processor_id(), jiffies - rsp->gp_start); trigger_all_cpu_backtrace(); - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); if (ULONG_CMP_GE(jiffies, rsp->jiffies_stall)) rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK; - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); set_need_resched(); /* kick ourselves to get things going. */ } @@ -563,12 +563,12 @@ static void note_new_gpnum(struct rcu_state *rsp, struct rcu_data *rdp) local_irq_save(flags); rnp = rdp->mynode; if (rdp->gpnum == ACCESS_ONCE(rnp->gpnum) || /* outside lock. */ - !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */ + !raw_spin_trylock(&rnp->lock)) { /* irqs already off, so later. */ local_irq_restore(flags); return; } __note_new_gpnum(rsp, rnp, rdp); - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -627,12 +627,12 @@ rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp) local_irq_save(flags); rnp = rdp->mynode; if (rdp->completed == ACCESS_ONCE(rnp->completed) || /* outside lock. */ - !spin_trylock(&rnp->lock)) { /* irqs already off, retry later. */ + !raw_spin_trylock(&rnp->lock)) { /* irqs already off, so later. */ local_irq_restore(flags); return; } __rcu_process_gp_end(rsp, rnp, rdp); - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -681,10 +681,10 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) if (cpu_needs_another_gp(rsp, rdp)) rsp->fqs_need_gp = 1; if (rnp->completed == rsp->completed) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ /* * Propagate new ->completed value to rcu_node structures @@ -692,9 +692,9 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) * of the next grace period to process their callbacks. */ rcu_for_each_node_breadth_first(rsp, rnp) { - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->completed = rsp->completed; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } local_irq_restore(flags); return; @@ -715,15 +715,15 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rnp->completed = rsp->completed; rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */ rcu_start_gp_per_cpu(rsp, rnp, rdp); - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } - spin_unlock(&rnp->lock); /* leave irqs disabled. */ + raw_spin_unlock(&rnp->lock); /* leave irqs disabled. */ /* Exclude any concurrent CPU-hotplug operations. */ - spin_lock(&rsp->onofflock); /* irqs already disabled. */ + raw_spin_lock(&rsp->onofflock); /* irqs already disabled. */ /* * Set the quiescent-state-needed bits in all the rcu_node @@ -743,21 +743,21 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) * irqs disabled. */ rcu_for_each_node_breadth_first(rsp, rnp) { - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ rcu_preempt_check_blocked_tasks(rnp); rnp->qsmask = rnp->qsmaskinit; rnp->gpnum = rsp->gpnum; rnp->completed = rsp->completed; if (rnp == rdp->mynode) rcu_start_gp_per_cpu(rsp, rnp, rdp); - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } rnp = rcu_get_root(rsp); - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state now OK. */ - spin_unlock(&rnp->lock); /* irqs remain disabled. */ - spin_unlock_irqrestore(&rsp->onofflock, flags); + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock_irqrestore(&rsp->onofflock, flags); } /* @@ -796,14 +796,14 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, if (!(rnp->qsmask & mask)) { /* Our bit has already been cleared, so done. */ - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } rnp->qsmask &= ~mask; if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) { /* Other bits still set at this level, so done. */ - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } mask = rnp->grpmask; @@ -813,10 +813,10 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, break; } - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); rnp_c = rnp; rnp = rnp->parent; - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); WARN_ON_ONCE(rnp_c->qsmask); } @@ -845,7 +845,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long las struct rcu_node *rnp; rnp = rdp->mynode; - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); if (lastcomp != rnp->completed) { /* @@ -857,12 +857,12 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long las * race occurred. */ rdp->passed_quiesc = 0; /* try again later! */ - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } mask = rdp->grpmask; if ((rnp->qsmask & mask) == 0) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } else { rdp->qs_pending = 0; @@ -926,7 +926,7 @@ static void rcu_send_cbs_to_orphanage(struct rcu_state *rsp) if (rdp->nxtlist == NULL) return; /* irqs disabled, so comparison is stable. */ - spin_lock(&rsp->onofflock); /* irqs already disabled. */ + raw_spin_lock(&rsp->onofflock); /* irqs already disabled. */ *rsp->orphan_cbs_tail = rdp->nxtlist; rsp->orphan_cbs_tail = rdp->nxttail[RCU_NEXT_TAIL]; rdp->nxtlist = NULL; @@ -934,7 +934,7 @@ static void rcu_send_cbs_to_orphanage(struct rcu_state *rsp) rdp->nxttail[i] = &rdp->nxtlist; rsp->orphan_qlen += rdp->qlen; rdp->qlen = 0; - spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ + raw_spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ } /* @@ -945,10 +945,10 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp) unsigned long flags; struct rcu_data *rdp; - spin_lock_irqsave(&rsp->onofflock, flags); + raw_spin_lock_irqsave(&rsp->onofflock, flags); rdp = rsp->rda[smp_processor_id()]; if (rsp->orphan_cbs_list == NULL) { - spin_unlock_irqrestore(&rsp->onofflock, flags); + raw_spin_unlock_irqrestore(&rsp->onofflock, flags); return; } *rdp->nxttail[RCU_NEXT_TAIL] = rsp->orphan_cbs_list; @@ -957,7 +957,7 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp) rsp->orphan_cbs_list = NULL; rsp->orphan_cbs_tail = &rsp->orphan_cbs_list; rsp->orphan_qlen = 0; - spin_unlock_irqrestore(&rsp->onofflock, flags); + raw_spin_unlock_irqrestore(&rsp->onofflock, flags); } /* @@ -973,23 +973,23 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) struct rcu_node *rnp; /* Exclude any attempts to start a new grace period. */ - spin_lock_irqsave(&rsp->onofflock, flags); + raw_spin_lock_irqsave(&rsp->onofflock, flags); /* Remove the outgoing CPU from the masks in the rcu_node hierarchy. */ rnp = rdp->mynode; /* this is the outgoing CPU's rnp. */ mask = rdp->grpmask; /* rnp->grplo is constant. */ do { - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->qsmaskinit &= ~mask; if (rnp->qsmaskinit != 0) { if (rnp != rdp->mynode) - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ break; } if (rnp == rdp->mynode) need_report = rcu_preempt_offline_tasks(rsp, rnp, rdp); else - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ mask = rnp->grpmask; rnp = rnp->parent; } while (rnp != NULL); @@ -1000,12 +1000,12 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) * because invoking rcu_report_unblock_qs_rnp() with ->onofflock * held leads to deadlock. */ - spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ + raw_spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ rnp = rdp->mynode; if (need_report & RCU_OFL_TASKS_NORM_GP) rcu_report_unblock_qs_rnp(rnp, flags); else - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); if (need_report & RCU_OFL_TASKS_EXP_GP) rcu_report_exp_rnp(rsp, rnp); @@ -1176,13 +1176,13 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) rcu_for_each_leaf_node(rsp, rnp) { mask = 0; - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); if (!rcu_gp_in_progress(rsp)) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } if (rnp->qsmask == 0) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); continue; } cpu = rnp->grplo; @@ -1197,7 +1197,7 @@ static void force_qs_rnp(struct rcu_state *rsp, int (*f)(struct rcu_data *)) rcu_report_qs_rnp(mask, rsp, rnp, flags); continue; } - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } } @@ -1212,18 +1212,18 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) if (!rcu_gp_in_progress(rsp)) return; /* No grace period in progress, nothing to force. */ - if (!spin_trylock_irqsave(&rsp->fqslock, flags)) { + if (!raw_spin_trylock_irqsave(&rsp->fqslock, flags)) { rsp->n_force_qs_lh++; /* Inexact, can lose counts. Tough! */ return; /* Someone else is already on the job. */ } if (relaxed && ULONG_CMP_GE(rsp->jiffies_force_qs, jiffies)) goto unlock_fqs_ret; /* no emergency and done recently. */ rsp->n_force_qs++; - spin_lock(&rnp->lock); /* irqs already disabled */ + raw_spin_lock(&rnp->lock); /* irqs already disabled */ rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; if(!rcu_gp_in_progress(rsp)) { rsp->n_force_qs_ngp++; - spin_unlock(&rnp->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ goto unlock_fqs_ret; /* no GP in progress, time updated. */ } rsp->fqs_active = 1; @@ -1235,13 +1235,13 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_SAVE_DYNTICK: - spin_unlock(&rnp->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ if (RCU_SIGNAL_INIT != RCU_SAVE_DYNTICK) break; /* So gcc recognizes the dead code. */ /* Record dyntick-idle state. */ force_qs_rnp(rsp, dyntick_save_progress_counter); - spin_lock(&rnp->lock); /* irqs already disabled */ + raw_spin_lock(&rnp->lock); /* irqs already disabled */ if (rcu_gp_in_progress(rsp)) rsp->signaled = RCU_FORCE_QS; break; @@ -1249,24 +1249,24 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) case RCU_FORCE_QS: /* Check dyntick-idle state, send IPI to laggarts. */ - spin_unlock(&rnp->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ force_qs_rnp(rsp, rcu_implicit_dynticks_qs); /* Leave state in case more forcing is required. */ - spin_lock(&rnp->lock); /* irqs already disabled */ + raw_spin_lock(&rnp->lock); /* irqs already disabled */ break; } rsp->fqs_active = 0; if (rsp->fqs_need_gp) { - spin_unlock(&rsp->fqslock); /* irqs remain disabled */ + raw_spin_unlock(&rsp->fqslock); /* irqs remain disabled */ rsp->fqs_need_gp = 0; rcu_start_gp(rsp, flags); /* releases rnp->lock */ return; } - spin_unlock(&rnp->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ unlock_fqs_ret: - spin_unlock_irqrestore(&rsp->fqslock, flags); + raw_spin_unlock_irqrestore(&rsp->fqslock, flags); } #else /* #ifdef CONFIG_SMP */ @@ -1308,7 +1308,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) /* Does this CPU require a not-yet-started grace period? */ if (cpu_needs_another_gp(rsp, rdp)) { - spin_lock_irqsave(&rcu_get_root(rsp)->lock, flags); + raw_spin_lock_irqsave(&rcu_get_root(rsp)->lock, flags); rcu_start_gp(rsp, flags); /* releases above lock */ } @@ -1373,7 +1373,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), unsigned long nestflag; struct rcu_node *rnp_root = rcu_get_root(rsp); - spin_lock_irqsave(&rnp_root->lock, nestflag); + raw_spin_lock_irqsave(&rnp_root->lock, nestflag); rcu_start_gp(rsp, nestflag); /* releases rnp_root->lock. */ } @@ -1662,7 +1662,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) struct rcu_node *rnp = rcu_get_root(rsp); /* Set up local state, ensuring consistent view of global state. */ - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo); rdp->nxtlist = NULL; for (i = 0; i < RCU_NEXT_SIZE; i++) @@ -1672,7 +1672,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) rdp->dynticks = &per_cpu(rcu_dynticks, cpu); #endif /* #ifdef CONFIG_NO_HZ */ rdp->cpu = cpu; - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -1690,7 +1690,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) struct rcu_node *rnp = rcu_get_root(rsp); /* Set up local state, ensuring consistent view of global state. */ - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); rdp->passed_quiesc = 0; /* We could be racing with new GP, */ rdp->qs_pending = 1; /* so set up to respond to current GP. */ rdp->beenonline = 1; /* We have now been online. */ @@ -1698,7 +1698,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) rdp->qlen_last_fqs_check = 0; rdp->n_force_qs_snap = rsp->n_force_qs; rdp->blimit = blimit; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ /* * A new grace period might start here. If so, we won't be part @@ -1706,14 +1706,14 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) */ /* Exclude any attempts to start a new GP on large systems. */ - spin_lock(&rsp->onofflock); /* irqs already disabled. */ + raw_spin_lock(&rsp->onofflock); /* irqs already disabled. */ /* Add CPU to rcu_node bitmasks. */ rnp = rdp->mynode; mask = rdp->grpmask; do { /* Exclude any attempts to start a new GP on small systems. */ - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->qsmaskinit |= mask; mask = rnp->grpmask; if (rnp == rdp->mynode) { @@ -1721,11 +1721,11 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptable) rdp->completed = rnp->completed; rdp->passed_quiesc_completed = rnp->completed - 1; } - spin_unlock(&rnp->lock); /* irqs already disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs already disabled. */ rnp = rnp->parent; } while (rnp != NULL && !(rnp->qsmaskinit & mask)); - spin_unlock_irqrestore(&rsp->onofflock, flags); + raw_spin_unlock_irqrestore(&rsp->onofflock, flags); } static void __cpuinit rcu_online_cpu(int cpu) @@ -1832,7 +1832,7 @@ static void __init rcu_init_one(struct rcu_state *rsp) cpustride *= rsp->levelspread[i]; rnp = rsp->level[i]; for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) { - spin_lock_init(&rnp->lock); + raw_spin_lock_init(&rnp->lock); lockdep_set_class_and_name(&rnp->lock, &rcu_node_class[i], buf[i]); rnp->gpnum = 0; diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 7495fed49c30..6a82c34ce669 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -90,7 +90,7 @@ struct rcu_dynticks { * Definition for node within the RCU grace-period-detection hierarchy. */ struct rcu_node { - spinlock_t lock; /* Root rcu_node's lock protects some */ + raw_spinlock_t lock; /* Root rcu_node's lock protects some */ /* rcu_state fields as well as following. */ unsigned long gpnum; /* Current grace period for this node. */ /* This will either be equal to or one */ @@ -291,7 +291,7 @@ struct rcu_state { /* End of fields guarded by root rcu_node's lock. */ - spinlock_t onofflock; /* exclude on/offline and */ + raw_spinlock_t onofflock; /* exclude on/offline and */ /* starting new GP. Also */ /* protects the following */ /* orphan_cbs fields. */ @@ -301,7 +301,7 @@ struct rcu_state { /* going offline. */ struct rcu_head **orphan_cbs_tail; /* And tail pointer. */ long orphan_qlen; /* Number of orphaned cbs. */ - spinlock_t fqslock; /* Only one task forcing */ + raw_spinlock_t fqslock; /* Only one task forcing */ /* quiescent states. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index a82566696b0b..a8b2e834fd3a 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -111,7 +111,7 @@ static void rcu_preempt_note_context_switch(int cpu) /* Possibly blocking in an RCU read-side critical section. */ rdp = rcu_preempt_state.rda[cpu]; rnp = rdp->mynode; - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BLOCKED; t->rcu_blocked_node = rnp; @@ -132,7 +132,7 @@ static void rcu_preempt_note_context_switch(int cpu) WARN_ON_ONCE(!list_empty(&t->rcu_node_entry)); phase = (rnp->gpnum + !(rnp->qsmask & rdp->grpmask)) & 0x1; list_add(&t->rcu_node_entry, &rnp->blocked_tasks[phase]); - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -189,7 +189,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) struct rcu_node *rnp_p; if (rnp->qsmask != 0 || rcu_preempted_readers(rnp)) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); return; /* Still need more quiescent states! */ } @@ -206,8 +206,8 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) /* Report up the rest of the hierarchy. */ mask = rnp->grpmask; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ - spin_lock(&rnp_p->lock); /* irqs already disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_lock(&rnp_p->lock); /* irqs already disabled. */ rcu_report_qs_rnp(mask, &rcu_preempt_state, rnp_p, flags); } @@ -257,10 +257,10 @@ static void rcu_read_unlock_special(struct task_struct *t) */ for (;;) { rnp = t->rcu_blocked_node; - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ if (rnp == t->rcu_blocked_node) break; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } empty = !rcu_preempted_readers(rnp); empty_exp = !rcu_preempted_readers_exp(rnp); @@ -274,7 +274,7 @@ static void rcu_read_unlock_special(struct task_struct *t) * Note that rcu_report_unblock_qs_rnp() releases rnp->lock. */ if (empty) - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); else rcu_report_unblock_qs_rnp(rnp, flags); @@ -324,12 +324,12 @@ static void rcu_print_task_stall(struct rcu_node *rnp) struct task_struct *t; if (rcu_preempted_readers(rnp)) { - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); phase = rnp->gpnum & 0x1; lp = &rnp->blocked_tasks[phase]; list_for_each_entry(t, lp, rcu_node_entry) printk(" P%d", t->pid); - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } } @@ -400,11 +400,11 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp, lp_root = &rnp_root->blocked_tasks[i]; while (!list_empty(lp)) { tp = list_entry(lp->next, typeof(*tp), rcu_node_entry); - spin_lock(&rnp_root->lock); /* irqs already disabled */ + raw_spin_lock(&rnp_root->lock); /* irqs already disabled */ list_del(&tp->rcu_node_entry); tp->rcu_blocked_node = rnp_root; list_add(&tp->rcu_node_entry, lp_root); - spin_unlock(&rnp_root->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp_root->lock); /* irqs remain disabled */ } } return retval; @@ -528,7 +528,7 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) unsigned long flags; unsigned long mask; - spin_lock_irqsave(&rnp->lock, flags); + raw_spin_lock_irqsave(&rnp->lock, flags); for (;;) { if (!sync_rcu_preempt_exp_done(rnp)) break; @@ -537,12 +537,12 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp) break; } mask = rnp->grpmask; - spin_unlock(&rnp->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ rnp = rnp->parent; - spin_lock(&rnp->lock); /* irqs already disabled */ + raw_spin_lock(&rnp->lock); /* irqs already disabled */ rnp->expmask &= ~mask; } - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* @@ -557,11 +557,11 @@ sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp) { int must_wait; - spin_lock(&rnp->lock); /* irqs already disabled */ + raw_spin_lock(&rnp->lock); /* irqs already disabled */ list_splice_init(&rnp->blocked_tasks[0], &rnp->blocked_tasks[2]); list_splice_init(&rnp->blocked_tasks[1], &rnp->blocked_tasks[3]); must_wait = rcu_preempted_readers_exp(rnp); - spin_unlock(&rnp->lock); /* irqs remain disabled */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled */ if (!must_wait) rcu_report_exp_rnp(rsp, rnp); } @@ -606,13 +606,13 @@ void synchronize_rcu_expedited(void) /* force all RCU readers onto blocked_tasks[]. */ synchronize_sched_expedited(); - spin_lock_irqsave(&rsp->onofflock, flags); + raw_spin_lock_irqsave(&rsp->onofflock, flags); /* Initialize ->expmask for all non-leaf rcu_node structures. */ rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) { - spin_lock(&rnp->lock); /* irqs already disabled. */ + raw_spin_lock(&rnp->lock); /* irqs already disabled. */ rnp->expmask = rnp->qsmaskinit; - spin_unlock(&rnp->lock); /* irqs remain disabled. */ + raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } /* Snapshot current state of ->blocked_tasks[] lists. */ @@ -621,7 +621,7 @@ void synchronize_rcu_expedited(void) if (NUM_RCU_NODES > 1) sync_rcu_preempt_exp_init(rsp, rcu_get_root(rsp)); - spin_unlock_irqrestore(&rsp->onofflock, flags); + raw_spin_unlock_irqrestore(&rsp->onofflock, flags); /* Wait for snapshotted ->blocked_tasks[] lists to drain. */ rnp = rcu_get_root(rsp); @@ -756,7 +756,7 @@ static int rcu_preempted_readers(struct rcu_node *rnp) /* Because preemptible RCU does not exist, no quieting of tasks. */ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) { - spin_unlock_irqrestore(&rnp->lock, flags); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } #endif /* #ifdef CONFIG_HOTPLUG_CPU */ -- cgit v1.2.3 From 3acd9eb31c5f7eb97cb2009fa41472710fb4a10f Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:05:03 -0800 Subject: rcu: Fix deadlock in TREE_PREEMPT_RCU CPU stall detection Under TREE_PREEMPT_RCU, print_other_cpu_stall() invokes rcu_print_task_stall() with the root rcu_node structure's ->lock held, and rcu_print_task_stall() acquires that same lock for self-deadlock. Fix this by removing the lock acquisition from rcu_print_task_stall(), and making all callers acquire the lock instead. Tested-by: John Kacur Tested-by: Thomas Gleixner Located-by: Thomas Gleixner Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-19-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 2 ++ kernel/rcutree_plugin.h | 3 --- 2 files changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 65a807b4f58c..b07be37d2aa3 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -476,7 +476,9 @@ static void print_other_cpu_stall(struct rcu_state *rsp) printk(KERN_ERR "INFO: RCU detected CPU stalls:"); rcu_for_each_leaf_node(rsp, rnp) { + raw_spin_lock_irqsave(&rnp->lock, flags); rcu_print_task_stall(rnp); + raw_spin_unlock_irqrestore(&rnp->lock, flags); if (rnp->qsmask == 0) continue; for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++) diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index a8b2e834fd3a..aecfe37e0117 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -318,18 +318,15 @@ EXPORT_SYMBOL_GPL(__rcu_read_unlock); */ static void rcu_print_task_stall(struct rcu_node *rnp) { - unsigned long flags; struct list_head *lp; int phase; struct task_struct *t; if (rcu_preempted_readers(rnp)) { - raw_spin_lock_irqsave(&rnp->lock, flags); phase = rnp->gpnum & 0x1; lp = &rnp->blocked_tasks[phase]; list_for_each_entry(t, lp, rcu_node_entry) printk(" P%d", t->pid); - raw_spin_unlock_irqrestore(&rnp->lock, flags); } } -- cgit v1.2.3 From 6155fec92e85f07d99e9746234496215443ffb0d Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:05:04 -0800 Subject: rcu: Fix rcutorture mod_timer argument to delay one jiffy The current "mod_timer(&t, 1)" potentially makes the timer fire immediately, change this to wait one jiffy. Signed-off-by: Dan Carpenter Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-20-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutorture.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index 5f43f30fcd1d..258cdf0a91eb 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -853,7 +853,7 @@ rcu_torture_reader(void *arg) do { if (irqreader && cur_ops->irq_capable) { if (!timer_pending(&t)) - mod_timer(&t, 1); + mod_timer(&t, jiffies + 1); } idx = cur_ops->readlock(); completed = cur_ops->completed(); -- cgit v1.2.3 From 1ed509a225008c9e8c0644fbd22168e09a7383a0 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Mon, 22 Feb 2010 17:05:05 -0800 Subject: rcu: Add RCU_CPU_STALL_VERBOSE to dump detailed per-task information When RCU detects a grace-period stall, it currently just prints out the PID of any tasks doing the stalling. This patch adds RCU_CPU_STALL_VERBOSE, which enables the more-verbose reporting from sched_show_task(). Suggested-by: Thomas Gleixner Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-21-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 4 ++++ kernel/rcutree.h | 1 + kernel/rcutree_plugin.h | 52 +++++++++++++++++++++++++++++++++++++++++++++++++ lib/Kconfig.debug | 12 ++++++++++++ 4 files changed, 69 insertions(+) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index b07be37d2aa3..525d39810616 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -489,6 +489,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp) smp_processor_id(), (long)(jiffies - rsp->gp_start)); trigger_all_cpu_backtrace(); + /* If so configured, complain about tasks blocking the grace period. */ + + rcu_print_detail_task_stall(rsp); + force_quiescent_state(rsp, 0); /* Kick them all. */ } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 6a82c34ce669..2ceb08388582 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -352,6 +352,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_RCU_CPU_STALL_DETECTOR +static void rcu_print_detail_task_stall(struct rcu_state *rsp); static void rcu_print_task_stall(struct rcu_node *rnp); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index aecfe37e0117..3516de7091a1 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -312,6 +312,50 @@ EXPORT_SYMBOL_GPL(__rcu_read_unlock); #ifdef CONFIG_RCU_CPU_STALL_DETECTOR +#ifdef CONFIG_RCU_CPU_STALL_VERBOSE + +/* + * Dump detailed information for all tasks blocking the current RCU + * grace period on the specified rcu_node structure. + */ +static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp) +{ + unsigned long flags; + struct list_head *lp; + int phase; + struct task_struct *t; + + if (rcu_preempted_readers(rnp)) { + raw_spin_lock_irqsave(&rnp->lock, flags); + phase = rnp->gpnum & 0x1; + lp = &rnp->blocked_tasks[phase]; + list_for_each_entry(t, lp, rcu_node_entry) + sched_show_task(t); + raw_spin_unlock_irqrestore(&rnp->lock, flags); + } +} + +/* + * Dump detailed information for all tasks blocking the current RCU + * grace period. + */ +static void rcu_print_detail_task_stall(struct rcu_state *rsp) +{ + struct rcu_node *rnp = rcu_get_root(rsp); + + rcu_print_detail_task_stall_rnp(rnp); + rcu_for_each_leaf_node(rsp, rnp) + rcu_print_detail_task_stall_rnp(rnp); +} + +#else /* #ifdef CONFIG_RCU_CPU_STALL_VERBOSE */ + +static void rcu_print_detail_task_stall(struct rcu_state *rsp) +{ +} + +#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_VERBOSE */ + /* * Scan the current list of tasks blocked within RCU read-side critical * sections, printing out the tid of each. @@ -760,6 +804,14 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) #ifdef CONFIG_RCU_CPU_STALL_DETECTOR +/* + * Because preemptable RCU does not exist, we never have to check for + * tasks blocked within RCU read-side critical sections. + */ +static void rcu_print_detail_task_stall(struct rcu_state *rsp) +{ +} + /* * Because preemptable RCU does not exist, we never have to check for * tasks blocked within RCU read-side critical sections. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 6af20a8a0a54..4cdab452bfe2 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -781,6 +781,18 @@ config RCU_CPU_STALL_DETECTOR Say Y if you are unsure. +config RCU_CPU_STALL_VERBOSE + bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" + depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU + default n + help + This option causes RCU to printk detailed per-task information + for any tasks that are stalling the current RCU grace period. + + Say N if you are unsure. + + Say Y if you want to enable such checks. + config KPROBES_SANITY_TEST bool "Kprobes sanity tests" depends on DEBUG_KERNEL -- cgit v1.2.3 From c50cc75271759373bd89a036eec4d4269b291616 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 25 Feb 2010 12:02:13 +0100 Subject: sched, cgroups: Fix module export I have exported it in d11c563 - but cgroups.c did not have module.h included ... Cc: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/cgroup.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/cgroup.c b/kernel/cgroup.c index b1a0f5a528fe..4fd90e129772 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -23,6 +23,7 @@ */ #include +#include #include #include #include -- cgit v1.2.3 From 86c38a31aa7f2dd6e74a262710bf8ebf7455acc5 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Wed, 24 Feb 2010 13:59:23 -0500 Subject: tracing: Fix ftrace_event_call alignment for use with gcc 4.5 GCC 4.5 introduces behavior that forces the alignment of structures to use the largest possible value. The default value is 32 bytes, so if some structures are defined with a 4-byte alignment and others aren't declared with an alignment constraint at all - it will align at 32-bytes. For things like the ftrace events, this results in a non-standard array. When initializing the ftrace subsystem, we traverse the _ftrace_events section and call the initialization callback for each event. When the structures are misaligned, we could be treating another part of the structure (or the zeroed out space between them) as a function pointer. This patch forces the alignment for all the ftrace_event_call structures to 4 bytes. Without this patch, the kernel fails to boot very early when built with gcc 4.5. It's trivial to check the alignment of the members of the array, so it might be worthwhile to add something to the build system to do that automatically. Unfortunately, that only covers this case. I've asked one of the gcc developers about adding a warning when this condition is seen. Cc: stable@kernel.org Signed-off-by: Jeff Mahoney LKML-Reference: <4B85770B.6010901@suse.com> Signed-off-by: Steven Rostedt --- include/linux/syscalls.h | 6 ++++-- include/trace/ftrace.h | 3 ++- kernel/trace/trace.h | 3 ++- 3 files changed, 8 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 7b219696ad24..91bd7d78a07d 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -132,7 +132,8 @@ struct perf_event_attr; #define SYSCALL_TRACE_ENTER_EVENT(sname) \ static const struct syscall_metadata __syscall_meta_##sname; \ - static struct ftrace_event_call event_enter_##sname; \ + static struct ftrace_event_call \ + __attribute__((__aligned__(4))) event_enter_##sname; \ static struct trace_event enter_syscall_print_##sname = { \ .trace = print_syscall_enter, \ }; \ @@ -153,7 +154,8 @@ struct perf_event_attr; #define SYSCALL_TRACE_EXIT_EVENT(sname) \ static const struct syscall_metadata __syscall_meta_##sname; \ - static struct ftrace_event_call event_exit_##sname; \ + static struct ftrace_event_call \ + __attribute__((__aligned__(4))) event_exit_##sname; \ static struct trace_event exit_syscall_print_##sname = { \ .trace = print_syscall_exit, \ }; \ diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 09fd9afc0859..f23a0ca6910a 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -65,7 +65,8 @@ }; #undef DEFINE_EVENT #define DEFINE_EVENT(template, name, proto, args) \ - static struct ftrace_event_call event_##name + static struct ftrace_event_call \ + __attribute__((__aligned__(4))) event_##name #undef DEFINE_EVENT_PRINT #define DEFINE_EVENT_PRINT(template, name, proto, args, print) \ diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index b477fce41edf..fd05bcaf91b0 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -792,7 +792,8 @@ extern const char *__stop___trace_bprintk_fmt[]; #undef FTRACE_ENTRY #define FTRACE_ENTRY(call, struct_name, id, tstruct, print) \ - extern struct ftrace_event_call event_##call; + extern struct ftrace_event_call \ + __attribute__((__aligned__(4))) event_##call; #undef FTRACE_ENTRY_DUP #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print) \ FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print)) -- cgit v1.2.3 From 1ab83a89411556c4d5914dcf0d5da190178ae7db Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 24 Feb 2010 15:28:14 +0800 Subject: tracing: Remove CONFIG_TRACE_POWER from kernel config The power tracer has been converted to power trace events. Acked-by: Frederic Weisbecker Signed-off-by: Li Zefan LKML-Reference: <4B84D50E.4070806@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/Kconfig | 9 --------- 1 file changed, 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 6c22d8a2f289..ca2d3a8778b6 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -330,15 +330,6 @@ config BRANCH_TRACER Say N if unsure. -config POWER_TRACER - bool "Trace power consumption behavior" - depends on X86 - select GENERIC_TRACER - help - This tracer helps developers to analyze and optimize the kernel's - power management decisions, specifically the C-state and P-state - behavior. - config KSYM_TRACER bool "Trace read and write access on kernel memory locations" depends on HAVE_HW_BREAKPOINT -- cgit v1.2.3 From 6574658b3bc7c408581629de5efb809f125cce8c Mon Sep 17 00:00:00 2001 From: Wenji Huang Date: Wed, 24 Feb 2010 15:40:22 +0800 Subject: tracing: Fix typo in prof_sysexit_enable() Signed-off-by: Wenji Huang LKML-Reference: <1266997226-6833-1-git-send-email-wenji.huang@oracle.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_syscalls.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 49cea70fbf6d..8cdda95da81a 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -603,7 +603,7 @@ int prof_sysexit_enable(struct ftrace_event_call *call) ret = register_trace_sys_exit(prof_syscall_exit); if (ret) { pr_info("event trace: Could not activate" - "syscall entry trace point"); + "syscall exit trace point"); } else { set_bit(num, enabled_prof_exit_syscalls); sys_prof_refcount_exit++; -- cgit v1.2.3 From a5efd925115cbc1f90195dca9a25f7b8daa10c37 Mon Sep 17 00:00:00 2001 From: Wenji Huang Date: Wed, 24 Feb 2010 15:40:23 +0800 Subject: tracing: Fix typo of info text in trace_kprobe.c Signed-off-by: Wenji Huang LKML-Reference: <1266997226-6833-2-git-send-email-wenji.huang@oracle.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_kprobe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index c99029916c76..8d4bd16d6f70 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -651,12 +651,12 @@ static int create_trace_probe(int argc, char **argv) event = strchr(group, '/') + 1; event[-1] = '\0'; if (strlen(group) == 0) { - pr_info("Group name is not specifiled\n"); + pr_info("Group name is not specified\n"); return -EINVAL; } } if (strlen(event) == 0) { - pr_info("Event name is not specifiled\n"); + pr_info("Event name is not specified\n"); return -EINVAL; } } -- cgit v1.2.3 From c85f3a91f84d5a85f179c2504bb7a39370c82b41 Mon Sep 17 00:00:00 2001 From: Wenji Huang Date: Wed, 24 Feb 2010 15:40:24 +0800 Subject: tracing: Remove unnecessary variable in print_graph_return The "cpu" variable is declared at the start of the function and also within a branch, with the exact same initialization. Remove the local variable of the same name in the branch. Signed-off-by: Wenji Huang LKML-Reference: <1266997226-6833-3-git-send-email-wenji.huang@oracle.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 1 - 1 file changed, 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 616b135c9eb9..112561df2a0a 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -855,7 +855,6 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, int i; if (data) { - int cpu = iter->cpu; int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); /* -- cgit v1.2.3 From 7b60997f73865b019e595720185c85285ca3df9a Mon Sep 17 00:00:00 2001 From: Wenji Huang Date: Wed, 24 Feb 2010 15:40:26 +0800 Subject: tracing: Simplify memory recycle of trace_define_field Discard freeing field->type since it is not necessary. Reviewed-by: Li Zefan Signed-off-by: Wenji Huang LKML-Reference: <1266997226-6833-5-git-send-email-wenji.huang@oracle.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index c2a3077b7353..3f972ad98d04 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -60,10 +60,8 @@ int trace_define_field(struct ftrace_event_call *call, const char *type, return 0; err: - if (field) { + if (field) kfree(field->name); - kfree(field->type); - } kfree(field); return -ENOMEM; -- cgit v1.2.3 From 056ba4a9bea5f32781a36b797c562fb731e5eaa6 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Thu, 25 Feb 2010 14:06:46 -0800 Subject: rcu: Make lockdep_rcu_dereference() message less alarmist Change from "unsafe" to "suspicious", given that there will be false alarms. Suggested-by: Ingo Molnar Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267135607-7056-1-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/lockdep.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 672c436946ce..0c30d0455de1 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3816,9 +3816,9 @@ void lockdep_rcu_dereference(const char *file, const int line) if (!debug_locks_off()) return; - printk("\n==============================================\n"); - printk( "[ BUG: Unsafe rcu_dereference_check() usage! ]\n"); - printk( "----------------------------------------------\n"); + printk("\n===================================================\n"); + printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); + printk( "---------------------------------------------------\n"); printk("%s:%d invoked rcu_dereference_check() without protection!\n", file, line); printk("\nother info that might help us debug this:\n\n"); -- cgit v1.2.3 From d9f1bb6ad7fc53c406706f47858dd5ff030b14a3 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Thu, 25 Feb 2010 14:06:47 -0800 Subject: rcu: Make rcu_read_lock_sched_held() take boot time into account Before the scheduler starts, all tasks are non-preemptible by definition. So, during that time, rcu_read_lock_sched_held() needs to always return "true". This patch makes that be so. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267135607-7056-2-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/rcupdate.h | 4 +++- include/linux/rcutiny.h | 4 ---- include/linux/rcutree.h | 1 - kernel/rcupdate.c | 18 ++++++++++++++++++ kernel/rcutree.c | 19 ------------------- 5 files changed, 21 insertions(+), 25 deletions(-) (limited to 'kernel') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 1a4de31bd7b4..fcea332a8424 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -62,6 +62,8 @@ extern int sched_expedited_torture_stats(char *page); /* Internal to kernel */ extern void rcu_init(void); +extern int rcu_scheduler_active; +extern void rcu_scheduler_starting(void); #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include @@ -140,7 +142,7 @@ static inline int rcu_read_lock_sched_held(void) if (debug_locks) lockdep_opinion = lock_is_held(&rcu_sched_lock_map); - return lockdep_opinion || preempt_count() != 0; + return lockdep_opinion || preempt_count() != 0 || !rcu_scheduler_active; } #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 2b70d4e37383..a5195875480a 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -105,10 +105,6 @@ static inline void rcu_exit_nohz(void) #endif /* #else #ifdef CONFIG_NO_HZ */ -static inline void rcu_scheduler_starting(void) -{ -} - static inline void exit_rcu(void) { } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 704a010f686c..42cc3a04779e 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -35,7 +35,6 @@ struct notifier_block; extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); extern int rcu_needs_cpu(int cpu); -extern void rcu_scheduler_starting(void); extern int rcu_expedited_torture_stats(char *page); #ifdef CONFIG_TREE_PREEMPT_RCU diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 033cb55c26df..7bfa004572b1 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -44,6 +44,7 @@ #include #include #include +#include #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key rcu_lock_key; @@ -62,6 +63,23 @@ struct lockdep_map rcu_sched_lock_map = EXPORT_SYMBOL_GPL(rcu_sched_lock_map); #endif +int rcu_scheduler_active __read_mostly; + +/* + * This function is invoked towards the end of the scheduler's initialization + * process. Before this is called, the idle task might contain + * RCU read-side critical sections (during which time, this idle + * task is booting the system). After this function is called, the + * idle tasks are prohibited from containing RCU read-side critical + * sections. + */ +void rcu_scheduler_starting(void) +{ + WARN_ON(num_online_cpus() != 1); + WARN_ON(nr_context_switches() > 0); + rcu_scheduler_active = 1; +} + /* * Awaken the corresponding synchronize_rcu() instance now that a * grace period has elapsed. diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 525d39810616..335bfe4f0076 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -46,7 +46,6 @@ #include #include #include -#include #include "rcutree.h" @@ -81,9 +80,6 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data); struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); -static int rcu_scheduler_active __read_mostly; - - /* * Return true if an RCU grace period is in progress. The ACCESS_ONCE()s * permit this function to be invoked without holding the root rcu_node @@ -1565,21 +1561,6 @@ static int rcu_needs_cpu_quick_check(int cpu) rcu_preempt_needs_cpu(cpu); } -/* - * This function is invoked towards the end of the scheduler's initialization - * process. Before this is called, the idle task might contain - * RCU read-side critical sections (during which time, this idle - * task is booting the system). After this function is called, the - * idle tasks are prohibited from containing RCU read-side critical - * sections. - */ -void rcu_scheduler_starting(void) -{ - WARN_ON(num_online_cpus() != 1); - WARN_ON(nr_context_switches() > 0); - rcu_scheduler_active = 1; -} - static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL}; static atomic_t rcu_barrier_cpu_count; static DEFINE_MUTEX(rcu_barrier_mutex); -- cgit v1.2.3 From f5f654096487c6d526c47bb66308f9de81f091cf Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Thu, 25 Feb 2010 19:02:30 -0800 Subject: rcu: Export rcu_scheduler_active Kernel modules using rcu_read_lock_sched_held() must now have access to rcu_scheduler_active, so it must be exported. This should fix the fix for the boot-time RCU-lockdep splat. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <20100226030230.GA7743@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcupdate.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 7bfa004572b1..f1125c1a6321 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -64,6 +64,7 @@ EXPORT_SYMBOL_GPL(rcu_sched_lock_map); #endif int rcu_scheduler_active __read_mostly; +EXPORT_SYMBOL_GPL(rcu_scheduler_active); /* * This function is invoked towards the end of the scheduler's initialization -- cgit v1.2.3 From 3a0304e90aa5a2c0c308a05d28f7d109a48d8539 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 26 Feb 2010 10:33:41 +0100 Subject: perf_events: Report the MMAP pgoff value in bytes DaveM reported that currently perf interprets the pgoff value reported by the MMAP events as a byte range, but the kernel reports it as a page offset. Since its broken (and unusable) anyway, change the kernel behaviour (ABI) to report bytes indeed, avoiding the need for userspace to deal with PAGE_SIZE things. Reported-by: David Miller Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 087025fe3ba1..5a69abb05ac3 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3749,7 +3749,7 @@ void __perf_event_mmap(struct vm_area_struct *vma) /* .tid */ .start = vma->vm_start, .len = vma->vm_end - vma->vm_start, - .pgoff = vma->vm_pgoff, + .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, }, }; -- cgit v1.2.3 From d76a0812ac4139ceb54daab3cc70e1bd8bd9d43a Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Mon, 8 Feb 2010 17:06:01 +0200 Subject: perf_events: Add new start/stop PMU callbacks In certain situations, the kernel may need to stop and start the same event rapidly. The current PMU callbacks do not distinguish between stop and release (i.e., stop + free the resource). Thus, a counter may be released, then it will be immediately re-acquired. Event scheduling will again take place with no guarantee to assign the same counter. On some processors, this may event yield to failure to assign the event back due to competion between cores. This patch is adding a new pair of callback to stop and restart a counter without actually release the underlying counter resource. On stop, the counter is stopped, its values saved and that's it. On start, the value is reloaded and counter is restarted (on x86, actual restart is delayed until perf_enable()). Signed-off-by: Stephane Eranian [ added fallback to ->enable/->disable for all other PMUs fixed x86_pmu_start() to call x86_pmu.enable() merged __x86_pmu_disable into x86_pmu_stop() ] Signed-off-by: Peter Zijlstra LKML-Reference: <4b703875.0a04d00a.7896.ffffb824@mx.google.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 24 ++++++++++++++++++++---- include/linux/perf_event.h | 2 ++ kernel/perf_event.c | 20 ++++++++++++++++++-- 3 files changed, 40 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index a920f173a220..9173ea95f918 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1495,7 +1495,7 @@ static inline int match_prev_assignment(struct hw_perf_event *hwc, hwc->last_tag == cpuc->tags[i]; } -static void __x86_pmu_disable(struct perf_event *event, struct cpu_hw_events *cpuc); +static void x86_pmu_stop(struct perf_event *event); void hw_perf_enable(void) { @@ -1533,7 +1533,7 @@ void hw_perf_enable(void) match_prev_assignment(hwc, cpuc, i)) continue; - __x86_pmu_disable(event, cpuc); + x86_pmu_stop(event); hwc->idx = -1; } @@ -1801,6 +1801,19 @@ static int x86_pmu_enable(struct perf_event *event) return 0; } +static int x86_pmu_start(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + if (hwc->idx == -1) + return -EAGAIN; + + x86_perf_event_set_period(event, hwc, hwc->idx); + x86_pmu.enable(hwc, hwc->idx); + + return 0; +} + static void x86_pmu_unthrottle(struct perf_event *event) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); @@ -1924,8 +1937,9 @@ static void intel_pmu_drain_bts_buffer(struct cpu_hw_events *cpuc) event->pending_kill = POLL_IN; } -static void __x86_pmu_disable(struct perf_event *event, struct cpu_hw_events *cpuc) +static void x86_pmu_stop(struct perf_event *event) { + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; int idx = hwc->idx; @@ -1954,7 +1968,7 @@ static void x86_pmu_disable(struct perf_event *event) struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); int i; - __x86_pmu_disable(event, cpuc); + x86_pmu_stop(event); for (i = 0; i < cpuc->n_events; i++) { if (event == cpuc->event_list[i]) { @@ -2667,6 +2681,8 @@ static inline void x86_pmu_read(struct perf_event *event) static const struct pmu pmu = { .enable = x86_pmu_enable, .disable = x86_pmu_disable, + .start = x86_pmu_start, + .stop = x86_pmu_stop, .read = x86_pmu_read, .unthrottle = x86_pmu_unthrottle, }; diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 071a7db52549..b08dfdad08cb 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -513,6 +513,8 @@ struct perf_event; struct pmu { int (*enable) (struct perf_event *event); void (*disable) (struct perf_event *event); + int (*start) (struct perf_event *event); + void (*stop) (struct perf_event *event); void (*read) (struct perf_event *event); void (*unthrottle) (struct perf_event *event); }; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 5a69abb05ac3..74c60021cdbc 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1493,6 +1493,22 @@ do { \ return div64_u64(dividend, divisor); } +static void perf_event_stop(struct perf_event *event) +{ + if (!event->pmu->stop) + return event->pmu->disable(event); + + return event->pmu->stop(event); +} + +static int perf_event_start(struct perf_event *event) +{ + if (!event->pmu->start) + return event->pmu->enable(event); + + return event->pmu->start(event); +} + static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) { struct hw_perf_event *hwc = &event->hw; @@ -1513,9 +1529,9 @@ static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count) if (atomic64_read(&hwc->period_left) > 8*sample_period) { perf_disable(); - event->pmu->disable(event); + perf_event_stop(event); atomic64_set(&hwc->period_left, 0); - event->pmu->enable(event); + perf_event_start(event); perf_enable(); } } -- cgit v1.2.3 From 38331f62c20456454eed9ebea2525f072c6f1d2e Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Mon, 8 Feb 2010 17:17:01 +0200 Subject: perf_events, x86: AMD event scheduling This patch adds correct AMD NorthBridge event scheduling. NB events are events measuring L3 cache, Hypertransport traffic. They are identified by an event code >= 0xe0. They measure events on the Northbride which is shared by all cores on a package. NB events are counted on a shared set of counters. When a NB event is programmed in a counter, the data actually comes from a shared counter. Thus, access to those counters needs to be synchronized. We implement the synchronization such that no two cores can be measuring NB events using the same counters. Thus, we maintain a per-NB allocation table. The available slot is propagated using the event_constraint structure. Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra LKML-Reference: <4b703957.0702d00a.6bf2.7b7d@mx.google.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 265 ++++++++++++++++++++++++++++++++++++++- kernel/perf_event.c | 5 + 2 files changed, 267 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 9173ea95f918..aa12f36e4711 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -80,6 +80,13 @@ struct event_constraint { int weight; }; +struct amd_nb { + int nb_id; /* NorthBridge id */ + int refcnt; /* reference count */ + struct perf_event *owners[X86_PMC_IDX_MAX]; + struct event_constraint event_constraints[X86_PMC_IDX_MAX]; +}; + struct cpu_hw_events { struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */ unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)]; @@ -92,6 +99,7 @@ struct cpu_hw_events { int assign[X86_PMC_IDX_MAX]; /* event to counter assignment */ u64 tags[X86_PMC_IDX_MAX]; struct perf_event *event_list[X86_PMC_IDX_MAX]; /* in enabled order */ + struct amd_nb *amd_nb; }; #define __EVENT_CONSTRAINT(c, n, m, w) {\ @@ -153,6 +161,8 @@ struct x86_pmu { static struct x86_pmu x86_pmu __read_mostly; +static raw_spinlock_t amd_nb_lock; + static DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events) = { .enabled = 1, }; @@ -802,7 +812,7 @@ static u64 amd_pmu_event_map(int hw_event) static u64 amd_pmu_raw_event(u64 hw_event) { -#define K7_EVNTSEL_EVENT_MASK 0x7000000FFULL +#define K7_EVNTSEL_EVENT_MASK 0xF000000FFULL #define K7_EVNTSEL_UNIT_MASK 0x00000FF00ULL #define K7_EVNTSEL_EDGE_MASK 0x000040000ULL #define K7_EVNTSEL_INV_MASK 0x000800000ULL @@ -2210,6 +2220,7 @@ perf_event_nmi_handler(struct notifier_block *self, } static struct event_constraint unconstrained; +static struct event_constraint emptyconstraint; static struct event_constraint bts_constraint = EVENT_CONSTRAINT(0, 1ULL << X86_PMC_IDX_FIXED_BTS, 0); @@ -2249,10 +2260,146 @@ intel_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event return &unconstrained; } +/* + * AMD64 events are detected based on their event codes. + */ +static inline int amd_is_nb_event(struct hw_perf_event *hwc) +{ + return (hwc->config & 0xe0) == 0xe0; +} + +static void amd_put_event_constraints(struct cpu_hw_events *cpuc, + struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + struct amd_nb *nb = cpuc->amd_nb; + int i; + + /* + * only care about NB events + */ + if (!(nb && amd_is_nb_event(hwc))) + return; + + /* + * need to scan whole list because event may not have + * been assigned during scheduling + * + * no race condition possible because event can only + * be removed on one CPU at a time AND PMU is disabled + * when we come here + */ + for (i = 0; i < x86_pmu.num_events; i++) { + if (nb->owners[i] == event) { + cmpxchg(nb->owners+i, event, NULL); + break; + } + } +} + + /* + * AMD64 NorthBridge events need special treatment because + * counter access needs to be synchronized across all cores + * of a package. Refer to BKDG section 3.12 + * + * NB events are events measuring L3 cache, Hypertransport + * traffic. They are identified by an event code >= 0xe00. + * They measure events on the NorthBride which is shared + * by all cores on a package. NB events are counted on a + * shared set of counters. When a NB event is programmed + * in a counter, the data actually comes from a shared + * counter. Thus, access to those counters needs to be + * synchronized. + * + * We implement the synchronization such that no two cores + * can be measuring NB events using the same counters. Thus, + * we maintain a per-NB allocation table. The available slot + * is propagated using the event_constraint structure. + * + * We provide only one choice for each NB event based on + * the fact that only NB events have restrictions. Consequently, + * if a counter is available, there is a guarantee the NB event + * will be assigned to it. If no slot is available, an empty + * constraint is returned and scheduling will eventually fail + * for this event. + * + * Note that all cores attached the same NB compete for the same + * counters to host NB events, this is why we use atomic ops. Some + * multi-chip CPUs may have more than one NB. + * + * Given that resources are allocated (cmpxchg), they must be + * eventually freed for others to use. This is accomplished by + * calling amd_put_event_constraints(). + * + * Non NB events are not impacted by this restriction. + */ static struct event_constraint * amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) { - return &unconstrained; + struct hw_perf_event *hwc = &event->hw; + struct amd_nb *nb = cpuc->amd_nb; + struct perf_event *old = NULL; + int max = x86_pmu.num_events; + int i, j, k = -1; + + /* + * if not NB event or no NB, then no constraints + */ + if (!(nb && amd_is_nb_event(hwc))) + return &unconstrained; + + /* + * detect if already present, if so reuse + * + * cannot merge with actual allocation + * because of possible holes + * + * event can already be present yet not assigned (in hwc->idx) + * because of successive calls to x86_schedule_events() from + * hw_perf_group_sched_in() without hw_perf_enable() + */ + for (i = 0; i < max; i++) { + /* + * keep track of first free slot + */ + if (k == -1 && !nb->owners[i]) + k = i; + + /* already present, reuse */ + if (nb->owners[i] == event) + goto done; + } + /* + * not present, so grab a new slot + * starting either at: + */ + if (hwc->idx != -1) { + /* previous assignment */ + i = hwc->idx; + } else if (k != -1) { + /* start from free slot found */ + i = k; + } else { + /* + * event not found, no slot found in + * first pass, try again from the + * beginning + */ + i = 0; + } + j = i; + do { + old = cmpxchg(nb->owners+i, NULL, event); + if (!old) + break; + if (++i == max) + i = 0; + } while (i != j); +done: + if (!old) + return &nb->event_constraints[i]; + + return &emptyconstraint; } static int x86_event_sched_in(struct perf_event *event, @@ -2465,7 +2612,8 @@ static __initconst struct x86_pmu amd_pmu = { .apic = 1, /* use highest bit to detect overflow */ .max_period = (1ULL << 47) - 1, - .get_event_constraints = amd_get_event_constraints + .get_event_constraints = amd_get_event_constraints, + .put_event_constraints = amd_put_event_constraints }; static __init int p6_pmu_init(void) @@ -2589,6 +2737,91 @@ static __init int intel_pmu_init(void) return 0; } +static struct amd_nb *amd_alloc_nb(int cpu, int nb_id) +{ + struct amd_nb *nb; + int i; + + nb = kmalloc(sizeof(struct amd_nb), GFP_KERNEL); + if (!nb) + return NULL; + + memset(nb, 0, sizeof(*nb)); + nb->nb_id = nb_id; + + /* + * initialize all possible NB constraints + */ + for (i = 0; i < x86_pmu.num_events; i++) { + set_bit(i, nb->event_constraints[i].idxmsk); + nb->event_constraints[i].weight = 1; + } + return nb; +} + +static void amd_pmu_cpu_online(int cpu) +{ + struct cpu_hw_events *cpu1, *cpu2; + struct amd_nb *nb = NULL; + int i, nb_id; + + if (boot_cpu_data.x86_max_cores < 2) + return; + + /* + * function may be called too early in the + * boot process, in which case nb_id is bogus + */ + nb_id = amd_get_nb_id(cpu); + if (nb_id == BAD_APICID) + return; + + cpu1 = &per_cpu(cpu_hw_events, cpu); + cpu1->amd_nb = NULL; + + raw_spin_lock(&amd_nb_lock); + + for_each_online_cpu(i) { + cpu2 = &per_cpu(cpu_hw_events, i); + nb = cpu2->amd_nb; + if (!nb) + continue; + if (nb->nb_id == nb_id) + goto found; + } + + nb = amd_alloc_nb(cpu, nb_id); + if (!nb) { + pr_err("perf_events: failed NB allocation for CPU%d\n", cpu); + raw_spin_unlock(&amd_nb_lock); + return; + } +found: + nb->refcnt++; + cpu1->amd_nb = nb; + + raw_spin_unlock(&amd_nb_lock); +} + +static void amd_pmu_cpu_offline(int cpu) +{ + struct cpu_hw_events *cpuhw; + + if (boot_cpu_data.x86_max_cores < 2) + return; + + cpuhw = &per_cpu(cpu_hw_events, cpu); + + raw_spin_lock(&amd_nb_lock); + + if (--cpuhw->amd_nb->refcnt == 0) + kfree(cpuhw->amd_nb); + + cpuhw->amd_nb = NULL; + + raw_spin_unlock(&amd_nb_lock); +} + static __init int amd_pmu_init(void) { /* Performance-monitoring supported from K7 and later: */ @@ -2601,6 +2834,11 @@ static __init int amd_pmu_init(void) memcpy(hw_cache_event_ids, amd_hw_cache_event_ids, sizeof(hw_cache_event_ids)); + /* + * explicitly initialize the boot cpu, other cpus will get + * the cpu hotplug callbacks from smp_init() + */ + amd_pmu_cpu_online(smp_processor_id()); return 0; } @@ -2934,4 +3172,25 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) void hw_perf_event_setup_online(int cpu) { init_debug_store_on_cpu(cpu); + + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + amd_pmu_cpu_online(cpu); + break; + default: + return; + } +} + +void hw_perf_event_setup_offline(int cpu) +{ + init_debug_store_on_cpu(cpu); + + switch (boot_cpu_data.x86_vendor) { + case X86_VENDOR_AMD: + amd_pmu_cpu_offline(cpu); + break; + default: + return; + } } diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 74c60021cdbc..fb4e56eb58f4 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -98,6 +98,7 @@ void __weak hw_perf_enable(void) { barrier(); } void __weak hw_perf_event_setup(int cpu) { barrier(); } void __weak hw_perf_event_setup_online(int cpu) { barrier(); } +void __weak hw_perf_event_setup_offline(int cpu) { barrier(); } int __weak hw_perf_group_sched_in(struct perf_event *group_leader, @@ -5462,6 +5463,10 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) perf_event_exit_cpu(cpu); break; + case CPU_DEAD: + hw_perf_event_setup_offline(cpu); + break; + default: break; } -- cgit v1.2.3 From 6e37738a2fac964583debe91099bc3248554f6e5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 11 Feb 2010 13:21:58 +0100 Subject: perf_events: Simplify code by removing cpu argument to hw_perf_group_sched_in() Since the cpu argument to hw_perf_group_sched_in() is always smp_processor_id(), simplify the code a little by removing this argument and using the current cpu where needed. Signed-off-by: Peter Zijlstra Cc: David Miller Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Frederic Weisbecker LKML-Reference: <1265890918.5396.3.camel@laptop> Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/perf_event.c | 10 ++++----- arch/sparc/kernel/perf_event.c | 10 ++++----- arch/x86/kernel/cpu/perf_event.c | 18 ++++++++-------- include/linux/perf_event.h | 2 +- kernel/perf_event.c | 45 ++++++++++++++++------------------------ 5 files changed, 38 insertions(+), 47 deletions(-) (limited to 'kernel') diff --git a/arch/powerpc/kernel/perf_event.c b/arch/powerpc/kernel/perf_event.c index 1eb85fbf53a5..b6cf8f1f4d35 100644 --- a/arch/powerpc/kernel/perf_event.c +++ b/arch/powerpc/kernel/perf_event.c @@ -718,10 +718,10 @@ static int collect_events(struct perf_event *group, int max_count, return n; } -static void event_sched_in(struct perf_event *event, int cpu) +static void event_sched_in(struct perf_event *event) { event->state = PERF_EVENT_STATE_ACTIVE; - event->oncpu = cpu; + event->oncpu = smp_processor_id(); event->tstamp_running += event->ctx->time - event->tstamp_stopped; if (is_software_event(event)) event->pmu->enable(event); @@ -735,7 +735,7 @@ static void event_sched_in(struct perf_event *event, int cpu) */ int hw_perf_group_sched_in(struct perf_event *group_leader, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, int cpu) + struct perf_event_context *ctx) { struct cpu_hw_events *cpuhw; long i, n, n0; @@ -766,10 +766,10 @@ int hw_perf_group_sched_in(struct perf_event *group_leader, cpuhw->event[i]->hw.config = cpuhw->events[i]; cpuctx->active_oncpu += n; n = 1; - event_sched_in(group_leader, cpu); + event_sched_in(group_leader); list_for_each_entry(sub, &group_leader->sibling_list, group_entry) { if (sub->state != PERF_EVENT_STATE_OFF) { - event_sched_in(sub, cpu); + event_sched_in(sub); ++n; } } diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index e856456ec02f..9f2b2bac8b2b 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -980,10 +980,10 @@ static int collect_events(struct perf_event *group, int max_count, return n; } -static void event_sched_in(struct perf_event *event, int cpu) +static void event_sched_in(struct perf_event *event) { event->state = PERF_EVENT_STATE_ACTIVE; - event->oncpu = cpu; + event->oncpu = smp_processor_id(); event->tstamp_running += event->ctx->time - event->tstamp_stopped; if (is_software_event(event)) event->pmu->enable(event); @@ -991,7 +991,7 @@ static void event_sched_in(struct perf_event *event, int cpu) int hw_perf_group_sched_in(struct perf_event *group_leader, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, int cpu) + struct perf_event_context *ctx) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct perf_event *sub; @@ -1015,10 +1015,10 @@ int hw_perf_group_sched_in(struct perf_event *group_leader, cpuctx->active_oncpu += n; n = 1; - event_sched_in(group_leader, cpu); + event_sched_in(group_leader); list_for_each_entry(sub, &group_leader->sibling_list, group_entry) { if (sub->state != PERF_EVENT_STATE_OFF) { - event_sched_in(sub, cpu); + event_sched_in(sub); n++; } } diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index aa12f36e4711..ad096562d694 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -2403,12 +2403,12 @@ done: } static int x86_event_sched_in(struct perf_event *event, - struct perf_cpu_context *cpuctx, int cpu) + struct perf_cpu_context *cpuctx) { int ret = 0; event->state = PERF_EVENT_STATE_ACTIVE; - event->oncpu = cpu; + event->oncpu = smp_processor_id(); event->tstamp_running += event->ctx->time - event->tstamp_stopped; if (!is_x86_event(event)) @@ -2424,7 +2424,7 @@ static int x86_event_sched_in(struct perf_event *event, } static void x86_event_sched_out(struct perf_event *event, - struct perf_cpu_context *cpuctx, int cpu) + struct perf_cpu_context *cpuctx) { event->state = PERF_EVENT_STATE_INACTIVE; event->oncpu = -1; @@ -2452,9 +2452,9 @@ static void x86_event_sched_out(struct perf_event *event, */ int hw_perf_group_sched_in(struct perf_event *leader, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, int cpu) + struct perf_event_context *ctx) { - struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu); + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct perf_event *sub; int assign[X86_PMC_IDX_MAX]; int n0, n1, ret; @@ -2468,14 +2468,14 @@ int hw_perf_group_sched_in(struct perf_event *leader, if (ret) return ret; - ret = x86_event_sched_in(leader, cpuctx, cpu); + ret = x86_event_sched_in(leader, cpuctx); if (ret) return ret; n1 = 1; list_for_each_entry(sub, &leader->sibling_list, group_entry) { if (sub->state > PERF_EVENT_STATE_OFF) { - ret = x86_event_sched_in(sub, cpuctx, cpu); + ret = x86_event_sched_in(sub, cpuctx); if (ret) goto undo; ++n1; @@ -2500,11 +2500,11 @@ int hw_perf_group_sched_in(struct perf_event *leader, */ return 1; undo: - x86_event_sched_out(leader, cpuctx, cpu); + x86_event_sched_out(leader, cpuctx); n0 = 1; list_for_each_entry(sub, &leader->sibling_list, group_entry) { if (sub->state == PERF_EVENT_STATE_ACTIVE) { - x86_event_sched_out(sub, cpuctx, cpu); + x86_event_sched_out(sub, cpuctx); if (++n0 == n1) break; } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index b08dfdad08cb..d0e072c5b58a 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -772,7 +772,7 @@ extern int perf_event_task_disable(void); extern int perf_event_task_enable(void); extern int hw_perf_group_sched_in(struct perf_event *group_leader, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, int cpu); + struct perf_event_context *ctx); extern void perf_event_update_userpage(struct perf_event *event); extern int perf_event_release_kernel(struct perf_event *event); extern struct perf_event * diff --git a/kernel/perf_event.c b/kernel/perf_event.c index fb4e56eb58f4..05b6c6b825e3 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -103,7 +103,7 @@ void __weak hw_perf_event_setup_offline(int cpu) { barrier(); } int __weak hw_perf_group_sched_in(struct perf_event *group_leader, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, int cpu) + struct perf_event_context *ctx) { return 0; } @@ -633,14 +633,13 @@ void perf_event_disable(struct perf_event *event) static int event_sched_in(struct perf_event *event, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, - int cpu) + struct perf_event_context *ctx) { if (event->state <= PERF_EVENT_STATE_OFF) return 0; event->state = PERF_EVENT_STATE_ACTIVE; - event->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */ + event->oncpu = smp_processor_id(); /* * The new state must be visible before we turn it on in the hardware: */ @@ -667,8 +666,7 @@ event_sched_in(struct perf_event *event, static int group_sched_in(struct perf_event *group_event, struct perf_cpu_context *cpuctx, - struct perf_event_context *ctx, - int cpu) + struct perf_event_context *ctx) { struct perf_event *event, *partial_group; int ret; @@ -676,18 +674,18 @@ group_sched_in(struct perf_event *group_event, if (group_event->state == PERF_EVENT_STATE_OFF) return 0; - ret = hw_perf_group_sched_in(group_event, cpuctx, ctx, cpu); + ret = hw_perf_group_sched_in(group_event, cpuctx, ctx); if (ret) return ret < 0 ? ret : 0; - if (event_sched_in(group_event, cpuctx, ctx, cpu)) + if (event_sched_in(group_event, cpuctx, ctx)) return -EAGAIN; /* * Schedule in siblings as one group (if any): */ list_for_each_entry(event, &group_event->sibling_list, group_entry) { - if (event_sched_in(event, cpuctx, ctx, cpu)) { + if (event_sched_in(event, cpuctx, ctx)) { partial_group = event; goto group_error; } @@ -761,7 +759,6 @@ static void __perf_install_in_context(void *info) struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; struct perf_event *leader = event->group_leader; - int cpu = smp_processor_id(); int err; /* @@ -808,7 +805,7 @@ static void __perf_install_in_context(void *info) if (!group_can_go_on(event, cpuctx, 1)) err = -EEXIST; else - err = event_sched_in(event, cpuctx, ctx, cpu); + err = event_sched_in(event, cpuctx, ctx); if (err) { /* @@ -950,11 +947,9 @@ static void __perf_event_enable(void *info) } else { perf_disable(); if (event == leader) - err = group_sched_in(event, cpuctx, ctx, - smp_processor_id()); + err = group_sched_in(event, cpuctx, ctx); else - err = event_sched_in(event, cpuctx, ctx, - smp_processor_id()); + err = event_sched_in(event, cpuctx, ctx); perf_enable(); } @@ -1281,19 +1276,18 @@ static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, static void ctx_pinned_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx, - int cpu) + struct perf_cpu_context *cpuctx) { struct perf_event *event; list_for_each_entry(event, &ctx->pinned_groups, group_entry) { if (event->state <= PERF_EVENT_STATE_OFF) continue; - if (event->cpu != -1 && event->cpu != cpu) + if (event->cpu != -1 && event->cpu != smp_processor_id()) continue; if (group_can_go_on(event, cpuctx, 1)) - group_sched_in(event, cpuctx, ctx, cpu); + group_sched_in(event, cpuctx, ctx); /* * If this pinned group hasn't been scheduled, @@ -1308,8 +1302,7 @@ ctx_pinned_sched_in(struct perf_event_context *ctx, static void ctx_flexible_sched_in(struct perf_event_context *ctx, - struct perf_cpu_context *cpuctx, - int cpu) + struct perf_cpu_context *cpuctx) { struct perf_event *event; int can_add_hw = 1; @@ -1322,11 +1315,11 @@ ctx_flexible_sched_in(struct perf_event_context *ctx, * Listen to the 'cpu' scheduling filter constraint * of events: */ - if (event->cpu != -1 && event->cpu != cpu) + if (event->cpu != -1 && event->cpu != smp_processor_id()) continue; if (group_can_go_on(event, cpuctx, can_add_hw)) - if (group_sched_in(event, cpuctx, ctx, cpu)) + if (group_sched_in(event, cpuctx, ctx)) can_add_hw = 0; } } @@ -1336,8 +1329,6 @@ ctx_sched_in(struct perf_event_context *ctx, struct perf_cpu_context *cpuctx, enum event_type_t event_type) { - int cpu = smp_processor_id(); - raw_spin_lock(&ctx->lock); ctx->is_active = 1; if (likely(!ctx->nr_events)) @@ -1352,11 +1343,11 @@ ctx_sched_in(struct perf_event_context *ctx, * in order to give them the best chance of going on. */ if (event_type & EVENT_PINNED) - ctx_pinned_sched_in(ctx, cpuctx, cpu); + ctx_pinned_sched_in(ctx, cpuctx); /* Then walk through the lower prio flexible groups */ if (event_type & EVENT_FLEXIBLE) - ctx_flexible_sched_in(ctx, cpuctx, cpu); + ctx_flexible_sched_in(ctx, cpuctx); perf_enable(); out: -- cgit v1.2.3 From dd5feea14a7de4edbd9f36db1a2db785de91b88d Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Tue, 23 Feb 2010 16:13:52 -0800 Subject: sched: Fix SCHED_MC regression caused by change in sched cpu_power On platforms like dual socket quad-core platform, the scheduler load balancer is not detecting the load imbalances in certain scenarios. This is leading to scenarios like where one socket is completely busy (with all the 4 cores running with 4 tasks) and leaving another socket completely idle. This causes performance issues as those 4 tasks share the memory controller, last-level cache bandwidth etc. Also we won't be taking advantage of turbo-mode as much as we would like, etc. Some of the comparisons in the scheduler load balancing code are comparing the "weighted cpu load that is scaled wrt sched_group's cpu_power" with the "weighted average load per task that is not scaled wrt sched_group's cpu_power". While this has probably been broken for a longer time (for multi socket numa nodes etc), the problem got aggrevated via this recent change: | | commit f93e65c186ab3c05ce2068733ca10e34fd00125e | Author: Peter Zijlstra | Date: Tue Sep 1 10:34:32 2009 +0200 | | sched: Restore __cpu_power to a straight sum of power | Also with this change, the sched group cpu power alone no longer reflects the group capacity that is needed to implement MC, MT performance (default) and power-savings (user-selectable) policies. We need to use the computed group capacity (sgs.group_capacity, that is computed using the SD_PREFER_SIBLING logic in update_sd_lb_stats()) to find out if the group with the max load is above its capacity and how much load to move etc. Reported-by: Ma Ling Initial-Analysis-by: Zhang, Yanmin Signed-off-by: Suresh Siddha [ -v2: build fix ] Signed-off-by: Peter Zijlstra Cc: # [2.6.32.x, 2.6.33.x] LKML-Reference: <1266970432.11588.22.camel@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 76 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 43 insertions(+), 33 deletions(-) (limited to 'kernel') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index ff7692ccda89..3e1fd96c6cf9 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -2097,6 +2097,7 @@ struct sd_lb_stats { unsigned long max_load; unsigned long busiest_load_per_task; unsigned long busiest_nr_running; + unsigned long busiest_group_capacity; int group_imb; /* Is there imbalance in this sd */ #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) @@ -2416,14 +2417,12 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, unsigned long load, max_cpu_load, min_cpu_load; int i; unsigned int balance_cpu = -1, first_idle_cpu = 0; - unsigned long sum_avg_load_per_task; - unsigned long avg_load_per_task; + unsigned long avg_load_per_task = 0; if (local_group) balance_cpu = group_first_cpu(group); /* Tally up the load of all CPUs in the group */ - sum_avg_load_per_task = avg_load_per_task = 0; max_cpu_load = 0; min_cpu_load = ~0UL; @@ -2453,7 +2452,6 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, sgs->sum_nr_running += rq->nr_running; sgs->sum_weighted_load += weighted_cpuload(i); - sum_avg_load_per_task += cpu_avg_load_per_task(i); } /* @@ -2473,7 +2471,6 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, /* Adjust by relative CPU power of the group */ sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power; - /* * Consider the group unbalanced when the imbalance is larger * than the average weight of two tasks. @@ -2483,8 +2480,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, * normalized nr_running number somewhere that negates * the hierarchy? */ - avg_load_per_task = (sum_avg_load_per_task * SCHED_LOAD_SCALE) / - group->cpu_power; + if (sgs->sum_nr_running) + avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) sgs->group_imb = 1; @@ -2553,6 +2550,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, sds->max_load = sgs.avg_load; sds->busiest = group; sds->busiest_nr_running = sgs.sum_nr_running; + sds->busiest_group_capacity = sgs.group_capacity; sds->busiest_load_per_task = sgs.sum_weighted_load; sds->group_imb = sgs.group_imb; } @@ -2575,6 +2573,7 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, { unsigned long tmp, pwr_now = 0, pwr_move = 0; unsigned int imbn = 2; + unsigned long scaled_busy_load_per_task; if (sds->this_nr_running) { sds->this_load_per_task /= sds->this_nr_running; @@ -2585,8 +2584,12 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, sds->this_load_per_task = cpu_avg_load_per_task(this_cpu); - if (sds->max_load - sds->this_load + sds->busiest_load_per_task >= - sds->busiest_load_per_task * imbn) { + scaled_busy_load_per_task = sds->busiest_load_per_task + * SCHED_LOAD_SCALE; + scaled_busy_load_per_task /= sds->busiest->cpu_power; + + if (sds->max_load - sds->this_load + scaled_busy_load_per_task >= + (scaled_busy_load_per_task * imbn)) { *imbalance = sds->busiest_load_per_task; return; } @@ -2637,7 +2640,14 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds, static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, unsigned long *imbalance) { - unsigned long max_pull; + unsigned long max_pull, load_above_capacity = ~0UL; + + sds->busiest_load_per_task /= sds->busiest_nr_running; + if (sds->group_imb) { + sds->busiest_load_per_task = + min(sds->busiest_load_per_task, sds->avg_load); + } + /* * In the presence of smp nice balancing, certain scenarios can have * max load less than avg load(as we skip the groups at or below @@ -2648,9 +2658,29 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu, return fix_small_imbalance(sds, this_cpu, imbalance); } - /* Don't want to pull so many tasks that a group would go idle */ - max_pull = min(sds->max_load - sds->avg_load, - sds->max_load - sds->busiest_load_per_task); + if (!sds->group_imb) { + /* + * Don't want to pull so many tasks that a group would go idle. + */ + load_above_capacity = (sds->busiest_nr_running - + sds->busiest_group_capacity); + + load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_LOAD_SCALE); + + load_above_capacity /= sds->busiest->cpu_power; + } + + /* + * We're trying to get all the cpus to the average_load, so we don't + * want to push ourselves above the average load, nor do we wish to + * reduce the max loaded cpu below the average load. At the same time, + * we also don't want to reduce the group load below the group capacity + * (so that we can implement power-savings policies etc). Thus we look + * for the minimum possible imbalance. + * Be careful of negative numbers as they'll appear as very large values + * with unsigned longs. + */ + max_pull = min(sds->max_load - sds->avg_load, load_above_capacity); /* How much load to actually move to equalise the imbalance */ *imbalance = min(max_pull * sds->busiest->cpu_power, @@ -2718,7 +2748,6 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, * 4) This group is more busy than the avg busieness at this * sched_domain. * 5) The imbalance is within the specified limit. - * 6) Any rebalance would lead to ping-pong */ if (!(*balance)) goto ret; @@ -2737,25 +2766,6 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load) goto out_balanced; - sds.busiest_load_per_task /= sds.busiest_nr_running; - if (sds.group_imb) - sds.busiest_load_per_task = - min(sds.busiest_load_per_task, sds.avg_load); - - /* - * We're trying to get all the cpus to the average_load, so we don't - * want to push ourselves above the average load, nor do we wish to - * reduce the max loaded cpu below the average load, as either of these - * actions would just result in more rebalancing later, and ping-pong - * tasks around. Thus we look for the minimum possible imbalance. - * Negative imbalances (*we* are more loaded than anyone else) will - * be counted as no imbalance for these purposes -- we can't fix that - * by pulling tasks to us. Be careful of negative numbers as they'll - * appear as very large values with unsigned longs. - */ - if (sds.max_load <= sds.busiest_load_per_task) - goto out_balanced; - /* Looks like there is an imbalance. Compute it */ calculate_imbalance(&sds, this_cpu, imbalance); return sds.busiest; -- cgit v1.2.3 From 24691ea964cc0123e386b661e03a86a481c6ee79 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 26 Feb 2010 16:36:23 +0100 Subject: perf_event: Fix preempt warning in perf_clock() A recent commit introduced a preemption warning for perf_clock(), use raw_smp_processor_id() to avoid this, it really doesn't matter which cpu we use here. Signed-off-by: Peter Zijlstra LKML-Reference: <1267198583.22519.684.camel@laptop> Cc: Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 05b6c6b825e3..aa6155b5e24c 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -249,7 +249,7 @@ static void perf_unpin_context(struct perf_event_context *ctx) static inline u64 perf_clock(void) { - return cpu_clock(smp_processor_id()); + return cpu_clock(raw_smp_processor_id()); } /* -- cgit v1.2.3 From 0e06b4a891c6a108412fe24b4500f499da2cf8a1 Mon Sep 17 00:00:00 2001 From: Rafael J. Wysocki Date: Sat, 23 Jan 2010 22:25:15 +0100 Subject: PM: Add a switch for disabling/enabling asynchronous suspend/resume Add sysfs attribute /sys/power/pm_async allowing the user space to disable/enable asynchronous suspend/resume of devices. Signed-off-by: Rafael J. Wysocki --- Documentation/ABI/testing/sysfs-power | 13 +++++++++++++ drivers/base/power/main.c | 7 ++++--- drivers/base/power/power.h | 6 +++--- kernel/power/main.c | 31 ++++++++++++++++++++++++++++++- 4 files changed, 50 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power index dcff4d0623ad..d6a801f45b48 100644 --- a/Documentation/ABI/testing/sysfs-power +++ b/Documentation/ABI/testing/sysfs-power @@ -101,3 +101,16 @@ Description: CAUTION: Using it will cause your machine's real-time (CMOS) clock to be set to a random invalid time after a resume. + +What: /sys/power/pm_async +Date: January 2009 +Contact: Rafael J. Wysocki +Description: + The /sys/power/pm_async file controls the switch allowing the + user space to enable or disable asynchronous suspend and resume + of devices. If enabled, this feature will cause some device + drivers' suspend and resume callbacks to be executed in parallel + with each other and with the main suspend thread. It is enabled + if this file contains "1", which is the default. It may be + disabled by writing "0" to this file, in which case all devices + will be suspended and resumed synchronously. diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 3b44c201ddad..7e79201b09bb 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -201,7 +201,7 @@ static void dpm_wait(struct device *dev, bool async) if (!dev) return; - if (async || dev->power.async_suspend) + if (async || (pm_async_enabled && dev->power.async_suspend)) wait_for_completion(&dev->power.completion); } @@ -563,7 +563,8 @@ static int device_resume(struct device *dev) { INIT_COMPLETION(dev->power.completion); - if (dev->power.async_suspend && !pm_trace_is_enabled()) { + if (pm_async_enabled && dev->power.async_suspend + && !pm_trace_is_enabled()) { get_device(dev); async_schedule(async_resume, dev); return 0; @@ -867,7 +868,7 @@ static int device_suspend(struct device *dev) { INIT_COMPLETION(dev->power.completion); - if (dev->power.async_suspend) { + if (pm_async_enabled && dev->power.async_suspend) { get_device(dev); async_schedule(async_suspend, dev); return 0; diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h index b8fa1aa5225a..c0bd03c83b9c 100644 --- a/drivers/base/power/power.h +++ b/drivers/base/power/power.h @@ -12,10 +12,10 @@ static inline void pm_runtime_remove(struct device *dev) {} #ifdef CONFIG_PM_SLEEP -/* - * main.c - */ +/* kernel/power/main.c */ +extern int pm_async_enabled; +/* drivers/base/power/main.c */ extern struct list_head dpm_list; /* The active device list */ static inline struct device *to_device(struct list_head *entry) diff --git a/kernel/power/main.c b/kernel/power/main.c index 0998c7139053..b58800b21fc0 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -44,6 +44,32 @@ int pm_notifier_call_chain(unsigned long val) == NOTIFY_BAD) ? -EINVAL : 0; } +/* If set, devices may be suspended and resumed asynchronously. */ +int pm_async_enabled = 1; + +static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%d\n", pm_async_enabled); +} + +static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t n) +{ + unsigned long val; + + if (strict_strtoul(buf, 10, &val)) + return -EINVAL; + + if (val > 1) + return -EINVAL; + + pm_async_enabled = val; + return n; +} + +power_attr(pm_async); + #ifdef CONFIG_PM_DEBUG int pm_test_level = TEST_NONE; @@ -208,8 +234,11 @@ static struct attribute * g[] = { #ifdef CONFIG_PM_TRACE &pm_trace_attr.attr, #endif -#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_PM_DEBUG) +#ifdef CONFIG_PM_SLEEP + &pm_async_attr.attr, +#ifdef CONFIG_PM_DEBUG &pm_test_attr.attr, +#endif #endif NULL, }; -- cgit v1.2.3 From 5a2eb8585f3b38e01e30aacaa8b985a1520a993d Mon Sep 17 00:00:00 2001 From: Rafael J. Wysocki Date: Sat, 23 Jan 2010 22:25:23 +0100 Subject: PM: Add facility for advanced testing of async suspend/resume Add configuration switch CONFIG_PM_ADVANCED_DEBUG for compiling in extra PM debugging/testing code allowing one to access some PM-related attributes of devices from the user space via sysfs. If CONFIG_PM_ADVANCED_DEBUG is set, add sysfs attribute power/async for every device allowing the user space to access the device's power.async_suspend flag and modify it, if desired. Signed-off-by: Rafael J. Wysocki --- Documentation/ABI/testing/sysfs-devices-power | 26 ++++++++++++++ drivers/base/power/sysfs.c | 49 +++++++++++++++++++++++++++ include/linux/device.h | 11 ++++++ kernel/power/Kconfig | 14 ++++++++ 4 files changed, 100 insertions(+) (limited to 'kernel') diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 431bfd7e65c7..6123c523bfd7 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -51,3 +51,29 @@ Description: drivers. Changing this attribute to "on" prevents the driver from power managing the device at run time. Doing that while the device is suspended causes it to be woken up. + +What: /sys/devices/.../power/async +Date: January 2009 +Contact: Rafael J. Wysocki +Description: + The /sys/devices/.../async attribute allows the user space to + enable or diasble the device's suspend and resume callbacks to + be executed asynchronously (ie. in separate threads, in parallel + with the main suspend/resume thread) during system-wide power + transitions (eg. suspend to RAM, hibernation). + + All devices have one of the following two values for the + power/async file: + + + "enabled\n" to permit the asynchronous suspend/resume; + + "disabled\n" to forbid it; + + The value of this attribute may be changed by writing either + "enabled", or "disabled" to it. + + It generally is unsafe to permit the asynchronous suspend/resume + of a device unless it is certain that all of the PM dependencies + of the device are known to the PM core. However, for some + devices this attribute is set to "enabled" by bus type code or + device drivers and in that cases it should be safe to leave the + default value. diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index c011ff15632c..86fd9373447e 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -54,6 +54,24 @@ * wakeup events internally (unless they are disabled), keeping * their hardware in low power modes whenever they're unused. This * saves runtime power, without requiring system-wide sleep states. + * + * async - Report/change current async suspend setting for the device + * + * Asynchronous suspend and resume of the device during system-wide power + * state transitions can be enabled by writing "enabled" to this file. + * Analogously, if "disabled" is written to this file, the device will be + * suspended and resumed synchronously. + * + * All devices have one of the following two values for power/async: + * + * + "enabled\n" to permit the asynchronous suspend/resume of the device; + * + "disabled\n" to forbid it; + * + * NOTE: It generally is unsafe to permit the asynchronous suspend/resume + * of a device unless it is certain that all of the PM dependencies of the + * device are known to the PM core. However, for some devices this + * attribute is set to "enabled" by bus type code or device drivers and in + * that cases it should be safe to leave the default value. */ static const char enabled[] = "enabled"; @@ -125,12 +143,43 @@ wake_store(struct device * dev, struct device_attribute *attr, static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store); +#ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG +static ssize_t async_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%s\n", + device_async_suspend_enabled(dev) ? enabled : disabled); +} + +static ssize_t async_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t n) +{ + char *cp; + int len = n; + + cp = memchr(buf, '\n', n); + if (cp) + len = cp - buf; + if (len == sizeof enabled - 1 && strncmp(buf, enabled, len) == 0) + device_enable_async_suspend(dev); + else if (len == sizeof disabled - 1 && strncmp(buf, disabled, len) == 0) + device_disable_async_suspend(dev); + else + return -EINVAL; + return n; +} + +static DEVICE_ATTR(async, 0644, async_show, async_store); +#endif /* CONFIG_PM_SLEEP_ADVANCED_DEBUG */ static struct attribute * power_attrs[] = { #ifdef CONFIG_PM_RUNTIME &dev_attr_control.attr, #endif &dev_attr_wakeup.attr, +#ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG + &dev_attr_async.attr, +#endif NULL, }; static struct attribute_group pm_attr_group = { diff --git a/include/linux/device.h b/include/linux/device.h index 70adc5f3f50a..b30527db3ac0 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -478,6 +478,17 @@ static inline void device_enable_async_suspend(struct device *dev) dev->power.async_suspend = true; } +static inline void device_disable_async_suspend(struct device *dev) +{ + if (dev->power.status == DPM_ON) + dev->power.async_suspend = false; +} + +static inline bool device_async_suspend_enabled(struct device *dev) +{ + return !!dev->power.async_suspend; +} + void driver_init(void); /* diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 4c9cffcf69c7..5c36ea9d55d2 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -27,6 +27,15 @@ config PM_DEBUG code. This is helpful when debugging and reporting PM bugs, like suspend support. +config PM_ADVANCED_DEBUG + bool "Extra PM attributes in sysfs for low-level debugging/testing" + depends on PM_DEBUG + default n + ---help--- + Add extra sysfs attributes allowing one to access some Power Management + fields of device objects from user space. If you are not a kernel + developer interested in debugging/testing Power Management, say "no". + config PM_VERBOSE bool "Verbose Power Management debugging" depends on PM_DEBUG @@ -85,6 +94,11 @@ config PM_SLEEP depends on SUSPEND || HIBERNATION || XEN_SAVE_RESTORE default y +config PM_SLEEP_ADVANCED_DEBUG + bool + depends on PM_ADVANCED_DEBUG + default n + config SUSPEND bool "Suspend to RAM and standby" depends on PM && ARCH_SUSPEND_POSSIBLE -- cgit v1.2.3 From b694e52ebdd439e4591d4a6651658026196174f6 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 27 Jan 2010 23:47:50 +0100 Subject: PM / Hibernate: Really deprecate deprecated user ioctls They were deprecated and removed from exported headers more than 2 years ago. Inform users about their removal in the future now. (Switch cases needed to be reorderded for an easy fall through.) And add an entry to feature-removal-schedule. Signed-off-by: Jiri Slaby Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki --- Documentation/feature-removal-schedule.txt | 11 +++++++++++ kernel/power/user.c | 23 +++++++++++++++++++---- 2 files changed, 30 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 0a46833c1b76..b9eba900e0f0 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -64,6 +64,17 @@ Who: Robin Getz & Matt Mackall --------------------------- +What: Deprecated snapshot ioctls +When: 2.6.36 + +Why: The ioctls in kernel/power/user.c were marked as deprecated long time + ago. Now they notify users about that so that they need to replace + their userspace. After some more time, remove them completely. + +Who: Jiri Slaby + +--------------------------- + What: The ieee80211_regdom module parameter When: March 2010 / desktop catchup diff --git a/kernel/power/user.c b/kernel/power/user.c index bf0014d6a5f0..4d2289626a84 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -195,6 +195,15 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf, return res; } +static void snapshot_deprecated_ioctl(unsigned int cmd) +{ + if (printk_ratelimit()) + printk(KERN_NOTICE "%pf: ioctl '%.8x' is deprecated and will " + "be removed soon, update your suspend-to-disk " + "utilities\n", + __builtin_return_address(0), cmd); +} + static long snapshot_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { @@ -246,8 +255,9 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, data->frozen = 0; break; - case SNAPSHOT_CREATE_IMAGE: case SNAPSHOT_ATOMIC_SNAPSHOT: + snapshot_deprecated_ioctl(cmd); + case SNAPSHOT_CREATE_IMAGE: if (data->mode != O_RDONLY || !data->frozen || data->ready) { error = -EPERM; break; @@ -275,8 +285,9 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, data->ready = 0; break; - case SNAPSHOT_PREF_IMAGE_SIZE: case SNAPSHOT_SET_IMAGE_SIZE: + snapshot_deprecated_ioctl(cmd); + case SNAPSHOT_PREF_IMAGE_SIZE: image_size = arg; break; @@ -290,15 +301,17 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, error = put_user(size, (loff_t __user *)arg); break; - case SNAPSHOT_AVAIL_SWAP_SIZE: case SNAPSHOT_AVAIL_SWAP: + snapshot_deprecated_ioctl(cmd); + case SNAPSHOT_AVAIL_SWAP_SIZE: size = count_swap_pages(data->swap, 1); size <<= PAGE_SHIFT; error = put_user(size, (loff_t __user *)arg); break; - case SNAPSHOT_ALLOC_SWAP_PAGE: case SNAPSHOT_GET_SWAP_PAGE: + snapshot_deprecated_ioctl(cmd); + case SNAPSHOT_ALLOC_SWAP_PAGE: if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { error = -ENODEV; break; @@ -321,6 +334,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, break; case SNAPSHOT_SET_SWAP_FILE: /* This ioctl is deprecated */ + snapshot_deprecated_ioctl(cmd); if (!swsusp_swap_in_use()) { /* * User space encodes device types as two-byte values, @@ -362,6 +376,7 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd, break; case SNAPSHOT_PMOPS: /* This ioctl is deprecated */ + snapshot_deprecated_ioctl(cmd); error = -EINVAL; switch (arg) { -- cgit v1.2.3 From 09c09bc618a4ceec387c57542031b4fc35826e16 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 27 Jan 2010 23:47:56 +0100 Subject: PM / Hibernate: Swap, remove useless check from swsusp_read() It will never reach here if the sws_resume_bdev is erratic. swsusp_read() is called only from software_resume(), but after swsusp_check() which would catch the error state. Signed-off-by: Jiri Slaby Signed-off-by: Rafael J. Wysocki --- kernel/power/swap.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'kernel') diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 09b2b0ae9e9d..1d575733d4e1 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -657,10 +657,6 @@ int swsusp_read(unsigned int *flags_p) struct swsusp_info *header; *flags_p = swsusp_header->flags; - if (IS_ERR(resume_bdev)) { - pr_debug("PM: Image device not initialised\n"); - return PTR_ERR(resume_bdev); - } memset(&snapshot, 0, sizeof(struct snapshot_handle)); error = snapshot_write_next(&snapshot, PAGE_SIZE); -- cgit v1.2.3 From 07c3bb5797d0a9a48524cca17ceb95711b48890b Mon Sep 17 00:00:00 2001 From: Frans Pop Date: Thu, 11 Feb 2010 23:09:08 +0100 Subject: PM / Hibernate: Remove trailing space in message Remove a trailing space from a message in swsusp_save(). Signed-off-by: Frans Pop Acked-by: Pavel Machek Signed-off-by: Rafael J. Wysocki --- kernel/power/snapshot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 36cb168e4330..2eda40741aaa 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1500,7 +1500,7 @@ asmlinkage int swsusp_save(void) { unsigned int nr_pages, nr_highmem; - printk(KERN_INFO "PM: Creating hibernation image: \n"); + printk(KERN_INFO "PM: Creating hibernation image:\n"); drain_local_pages(NULL); nr_pages = count_data_pages(); -- cgit v1.2.3 From f8bb0db8188c7ef9ef08515883dae9f9eb980984 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Sun, 21 Feb 2010 22:14:44 +0100 Subject: PM / Hibernate: Remove swsusp.c finally Its contents and entry in Makefile were already removed in 8e60c6a1348e17e68ad73589a52a03876e7059be (Shift remaining code from swsusp.c to hibernate.c) but somehow it remained in-place (rjw: which most likely was my mistake). Signed-off-by: Jiri Slaby Acked-by: Nigel Cunningham Signed-off-by: Rafael J. Wysocki --- kernel/power/swsusp.c | 58 --------------------------------------------------- 1 file changed, 58 deletions(-) delete mode 100644 kernel/power/swsusp.c (limited to 'kernel') diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c deleted file mode 100644 index 5b3601bd1893..000000000000 --- a/kernel/power/swsusp.c +++ /dev/null @@ -1,58 +0,0 @@ -/* - * linux/kernel/power/swsusp.c - * - * This file provides code to write suspend image to swap and read it back. - * - * Copyright (C) 1998-2001 Gabor Kuti - * Copyright (C) 1998,2001-2005 Pavel Machek - * - * This file is released under the GPLv2. - * - * I'd like to thank the following people for their work: - * - * Pavel Machek : - * Modifications, defectiveness pointing, being with me at the very beginning, - * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17. - * - * Steve Doddi : - * Support the possibility of hardware state restoring. - * - * Raph : - * Support for preserving states of network devices and virtual console - * (including X and svgatextmode) - * - * Kurt Garloff : - * Straightened the critical function in order to prevent compilers from - * playing tricks with local variables. - * - * Andreas Mohr - * - * Alex Badea : - * Fixed runaway init - * - * Rafael J. Wysocki - * Reworked the freeing of memory and the handling of swap - * - * More state savers are welcome. Especially for the scsi layer... - * - * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include "power.h" - -int in_suspend __nosavedata = 0; -- cgit v1.2.3 From a9c9b4429df437982d2fbfab1f4b46b01329e9ed Mon Sep 17 00:00:00 2001 From: Rafael J. Wysocki Date: Thu, 25 Feb 2010 22:32:37 +0100 Subject: PM / Hibernate: Fix preallocating of memory The hibernate memory preallocation code allocates memory to push some user space data out of physical RAM, so that the hibernation image is not too large. It allocates more memory than necessary for creating the image, so it has to release some pages to make room for allocations made while suspending devices and disabling nonboot CPUs, or the system will hang due to the lack of free pages to allocate from. Unfortunately, the function used for freeing these pages, free_unnecessary_pages(), contains a bug that prevents it from doing the job on all systems without highmem. Fix this problem, which is a regression from the 2.6.30 kernel, by using the right condition for the termination of the loop in free_unnecessary_pages(). Signed-off-by: Rafael J. Wysocki Reported-and-tested-by: Alan Jenkins Cc: stable@kernel.org --- kernel/power/snapshot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 2eda40741aaa..830cadecbdfc 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1181,7 +1181,7 @@ static void free_unnecessary_pages(void) memory_bm_position_reset(©_bm); - while (to_free_normal > 0 && to_free_highmem > 0) { + while (to_free_normal > 0 || to_free_highmem > 0) { unsigned long pfn = memory_bm_next_pfn(©_bm); struct page *page = pfn_to_page(pfn); -- cgit v1.2.3 From f1c7f517a5dc23bce07efa5ed55e2c074ed9d4ba Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 26 Feb 2010 17:08:16 -0500 Subject: ftrace: Add function names to dangling } in function graph tracer The function graph tracer is currently the most invasive tracer in the ftrace family. It can easily overflow the buffer even with 10megs per CPU. This means that events can often be lost. On start up, or after events are lost, if the function return is recorded but the function enter was lost, all we get to see is the exiting '}'. Here is how a typical trace output starts: [tracing] cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 0) + 91.897 us | } 0) ! 567.961 us | } 0) <========== | 0) ! 579.083 us | _raw_spin_lock_irqsave(); 0) 4.694 us | _raw_spin_unlock_irqrestore(); 0) ! 594.862 us | } 0) ! 603.361 us | } 0) ! 613.574 us | } 0) ! 623.554 us | } 0) 3.653 us | fget_light(); 0) | sock_poll() { There are a series of '}' with no matching "func() {". There's no information to what functions these ending brackets belong to. This patch adds a stack on the per cpu structure used in outputting the function graph tracer to keep track of what function was outputted. Then on a function exit event, it checks the depth to see if the function exit has a matching entry event. If it does, then it only prints the '}', otherwise it adds the function name after the '}'. This allows function exit events to show what function they belong to at trace output startup, when the entry was lost due to ring buffer overflow, or even after a new task is scheduled in. Here is what the above trace will look like after this patch: [tracing] cat trace # tracer: function_graph # # CPU DURATION FUNCTION CALLS # | | | | | | | 0) + 91.897 us | } (irq_exit) 0) ! 567.961 us | } (smp_apic_timer_interrupt) 0) <========== | 0) ! 579.083 us | _raw_spin_lock_irqsave(); 0) 4.694 us | _raw_spin_unlock_irqrestore(); 0) ! 594.862 us | } (add_wait_queue) 0) ! 603.361 us | } (__pollwait) 0) ! 613.574 us | } (tcp_poll) 0) ! 623.554 us | } (sock_poll) 0) 3.653 us | fget_light(); 0) | sock_poll() { Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 52 +++++++++++++++++++++++++++++------- 1 file changed, 43 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 112561df2a0a..e998a824e9db 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -18,6 +18,7 @@ struct fgraph_cpu_data { pid_t last_pid; int depth; int ignore; + unsigned long enter_funcs[FTRACE_RETFUNC_DEPTH]; }; struct fgraph_data { @@ -670,15 +671,21 @@ print_graph_entry_leaf(struct trace_iterator *iter, duration = graph_ret->rettime - graph_ret->calltime; if (data) { + struct fgraph_cpu_data *cpu_data; int cpu = iter->cpu; - int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); + + cpu_data = per_cpu_ptr(data->cpu_data, cpu); /* * Comments display at + 1 to depth. Since * this is a leaf function, keep the comments * equal to this depth. */ - *depth = call->depth - 1; + cpu_data->depth = call->depth - 1; + + /* No need to keep this function around for this depth */ + if (call->depth < FTRACE_RETFUNC_DEPTH) + cpu_data->enter_funcs[call->depth] = 0; } /* Overhead */ @@ -718,10 +725,15 @@ print_graph_entry_nested(struct trace_iterator *iter, int i; if (data) { + struct fgraph_cpu_data *cpu_data; int cpu = iter->cpu; - int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); - *depth = call->depth; + cpu_data = per_cpu_ptr(data->cpu_data, cpu); + cpu_data->depth = call->depth; + + /* Save this function pointer to see if the exit matches */ + if (call->depth < FTRACE_RETFUNC_DEPTH) + cpu_data->enter_funcs[call->depth] = call->func; } /* No overhead */ @@ -851,18 +863,28 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, struct fgraph_data *data = iter->private; pid_t pid = ent->pid; int cpu = iter->cpu; + int func_match = 1; int ret; int i; if (data) { - int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); + struct fgraph_cpu_data *cpu_data; + int cpu = iter->cpu; + + cpu_data = per_cpu_ptr(data->cpu_data, cpu); /* * Comments display at + 1 to depth. This is the * return from a function, we now want the comments * to display at the same level of the bracket. */ - *depth = trace->depth - 1; + cpu_data->depth = trace->depth - 1; + + if (trace->depth < FTRACE_RETFUNC_DEPTH) { + if (cpu_data->enter_funcs[trace->depth] != trace->func) + func_match = 0; + cpu_data->enter_funcs[trace->depth] = 0; + } } if (print_graph_prologue(iter, s, 0, 0)) @@ -887,9 +909,21 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, return TRACE_TYPE_PARTIAL_LINE; } - ret = trace_seq_printf(s, "}\n"); - if (!ret) - return TRACE_TYPE_PARTIAL_LINE; + /* + * If the return function does not have a matching entry, + * then the entry was lost. Instead of just printing + * the '}' and letting the user guess what function this + * belongs to, write out the function name. + */ + if (func_match) { + ret = trace_seq_printf(s, "}\n"); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + } else { + ret = trace_seq_printf(s, "} (%ps)\n", (void *)trace->func); + if (!ret) + return TRACE_TYPE_PARTIAL_LINE; + } /* Overrun */ if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) { -- cgit v1.2.3 From a47cd880b50e14b0b6f5e9d426ae9a2676c9c474 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Fri, 26 Feb 2010 16:38:56 -0800 Subject: rcu: Fix accelerated grace periods for last non-dynticked CPU It is invalid to invoke __rcu_process_callbacks() with irqs disabled, so do it indirectly via raise_softirq(). This requires a state-machine implementation to cycle through the grace-period machinery the required number of times. Located-by: Ingo Molnar Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267231138-27856-1-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 3 ++ kernel/rcutree.h | 1 + kernel/rcutree_plugin.h | 73 +++++++++++++++++++++++++++++++++++-------------- 3 files changed, 57 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 335bfe4f0076..3ec8160fc75f 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1341,6 +1341,9 @@ static void rcu_process_callbacks(struct softirq_action *unused) * grace-period manipulations above. */ smp_mb(); /* See above block comment. */ + + /* If we are last CPU on way to dyntick-idle mode, accelerate it. */ + rcu_needs_cpu_flush(); } static void diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 2ceb08388582..1439eb504c22 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -373,5 +373,6 @@ static int rcu_preempt_needs_cpu(int cpu); static void __cpuinit rcu_preempt_init_percpu_data(int cpu); static void rcu_preempt_send_cbs_to_orphanage(void); static void __init __rcu_init_preempt(void); +static void rcu_needs_cpu_flush(void); #endif /* #ifndef RCU_TREE_NONCORE */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 3516de7091a1..ed241fc478f0 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -973,9 +973,19 @@ int rcu_needs_cpu(int cpu) return rcu_needs_cpu_quick_check(cpu); } +/* + * Check to see if we need to continue a callback-flush operations to + * allow the last CPU to enter dyntick-idle mode. But fast dyntick-idle + * entry is not configured, so we never do need to. + */ +static void rcu_needs_cpu_flush(void) +{ +} + #else /* #if !defined(CONFIG_RCU_FAST_NO_HZ) */ #define RCU_NEEDS_CPU_FLUSHES 5 +static DEFINE_PER_CPU(int, rcu_dyntick_drain); /* * Check to see if any future RCU-related work will need to be done @@ -988,39 +998,62 @@ int rcu_needs_cpu(int cpu) * only if all other CPUs are already in dynticks-idle mode. This will * allow the CPU cores to be powered down immediately, as opposed to after * waiting many milliseconds for grace periods to elapse. + * + * Because it is not legal to invoke rcu_process_callbacks() with irqs + * disabled, we do one pass of force_quiescent_state(), then do a + * raise_softirq() to cause rcu_process_callbacks() to be invoked later. + * The per-cpu rcu_dyntick_drain variable controls the sequencing. */ int rcu_needs_cpu(int cpu) { - int c = 1; - int i; + int c = 0; int thatcpu; /* Don't bother unless we are the last non-dyntick-idle CPU. */ for_each_cpu_not(thatcpu, nohz_cpu_mask) - if (thatcpu != cpu) + if (thatcpu != cpu) { + per_cpu(rcu_dyntick_drain, cpu) = 0; return rcu_needs_cpu_quick_check(cpu); - - /* Try to push remaining RCU-sched and RCU-bh callbacks through. */ - for (i = 0; i < RCU_NEEDS_CPU_FLUSHES && c; i++) { - c = 0; - if (per_cpu(rcu_sched_data, cpu).nxtlist) { - rcu_sched_qs(cpu); - force_quiescent_state(&rcu_sched_state, 0); - __rcu_process_callbacks(&rcu_sched_state, - &per_cpu(rcu_sched_data, cpu)); - c = !!per_cpu(rcu_sched_data, cpu).nxtlist; - } - if (per_cpu(rcu_bh_data, cpu).nxtlist) { - rcu_bh_qs(cpu); - force_quiescent_state(&rcu_bh_state, 0); - __rcu_process_callbacks(&rcu_bh_state, - &per_cpu(rcu_bh_data, cpu)); - c = !!per_cpu(rcu_bh_data, cpu).nxtlist; } + + /* Check and update the rcu_dyntick_drain sequencing. */ + if (per_cpu(rcu_dyntick_drain, cpu) <= 0) { + /* First time through, initialize the counter. */ + per_cpu(rcu_dyntick_drain, cpu) = RCU_NEEDS_CPU_FLUSHES; + } else if (--per_cpu(rcu_dyntick_drain, cpu) <= 0) { + /* We have hit the limit, so time to give up. */ + return rcu_needs_cpu_quick_check(cpu); + } + + /* Do one step pushing remaining RCU callbacks through. */ + if (per_cpu(rcu_sched_data, cpu).nxtlist) { + rcu_sched_qs(cpu); + force_quiescent_state(&rcu_sched_state, 0); + c = c || per_cpu(rcu_sched_data, cpu).nxtlist; + } + if (per_cpu(rcu_bh_data, cpu).nxtlist) { + rcu_bh_qs(cpu); + force_quiescent_state(&rcu_bh_state, 0); + c = c || per_cpu(rcu_bh_data, cpu).nxtlist; } /* If RCU callbacks are still pending, RCU still needs this CPU. */ + if (c) + raise_softirq(RCU_SOFTIRQ); return c; } +/* + * Check to see if we need to continue a callback-flush operations to + * allow the last CPU to enter dyntick-idle mode. + */ +static void rcu_needs_cpu_flush(void) +{ + int cpu = smp_processor_id(); + + if (per_cpu(rcu_dyntick_drain, cpu) <= 0) + return; + (void)rcu_needs_cpu(cpu); +} + #endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */ -- cgit v1.2.3 From 71da81324c83ef65bb196c7f874ac1c6996d8287 Mon Sep 17 00:00:00 2001 From: Paul E. McKenney Date: Fri, 26 Feb 2010 16:38:58 -0800 Subject: rcu: Fix accelerated GPs for last non-dynticked CPU This patch disables irqs across the call to rcu_needs_cpu(). It also enforces a hold-off period so that the idle loop doesn't softirq itself to death when there are lots of RCU callbacks in flight on the last non-dynticked CPU. Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1267231138-27856-3-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/rcutree_plugin.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index ed241fc478f0..464ad2cdee00 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -986,6 +986,7 @@ static void rcu_needs_cpu_flush(void) #define RCU_NEEDS_CPU_FLUSHES 5 static DEFINE_PER_CPU(int, rcu_dyntick_drain); +static DEFINE_PER_CPU(unsigned long, rcu_dyntick_holdoff); /* * Check to see if any future RCU-related work will need to be done @@ -1013,6 +1014,7 @@ int rcu_needs_cpu(int cpu) for_each_cpu_not(thatcpu, nohz_cpu_mask) if (thatcpu != cpu) { per_cpu(rcu_dyntick_drain, cpu) = 0; + per_cpu(rcu_dyntick_holdoff, cpu) = jiffies - 1; return rcu_needs_cpu_quick_check(cpu); } @@ -1022,6 +1024,7 @@ int rcu_needs_cpu(int cpu) per_cpu(rcu_dyntick_drain, cpu) = RCU_NEEDS_CPU_FLUSHES; } else if (--per_cpu(rcu_dyntick_drain, cpu) <= 0) { /* We have hit the limit, so time to give up. */ + per_cpu(rcu_dyntick_holdoff, cpu) = jiffies; return rcu_needs_cpu_quick_check(cpu); } @@ -1038,8 +1041,10 @@ int rcu_needs_cpu(int cpu) } /* If RCU callbacks are still pending, RCU still needs this CPU. */ - if (c) + if (c) { raise_softirq(RCU_SOFTIRQ); + per_cpu(rcu_dyntick_holdoff, cpu) = jiffies; + } return c; } @@ -1050,10 +1055,13 @@ int rcu_needs_cpu(int cpu) static void rcu_needs_cpu_flush(void) { int cpu = smp_processor_id(); + unsigned long flags; if (per_cpu(rcu_dyntick_drain, cpu) <= 0) return; + local_irq_save(flags); (void)rcu_needs_cpu(cpu); + local_irq_restore(flags); } #endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */ -- cgit v1.2.3