From 582b336ec2c0f0076f5650a029fcc9abd4a906f7 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Tue, 27 Nov 2012 23:28:54 -0200 Subject: sched: add notifier for cross-cpu migrations Originally from Jeremy Fitzhardinge. Acked-by: Ingo Molnar Signed-off-by: Marcelo Tosatti --- kernel/sched/core.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'kernel') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2d8927fda712..c86b8b6e70f4 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -922,6 +922,13 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) rq->skip_clock_update = 1; } +static ATOMIC_NOTIFIER_HEAD(task_migration_notifier); + +void register_task_migration_notifier(struct notifier_block *n) +{ + atomic_notifier_chain_register(&task_migration_notifier, n); +} + #ifdef CONFIG_SMP void set_task_cpu(struct task_struct *p, unsigned int new_cpu) { @@ -952,8 +959,16 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) trace_sched_migrate_task(p, new_cpu); if (task_cpu(p) != new_cpu) { + struct task_migration_notifier tmn; + p->se.nr_migrations++; perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); + + tmn.task = p; + tmn.from_cpu = task_cpu(p); + tmn.to_cpu = new_cpu; + + atomic_notifier_call_chain(&task_migration_notifier, 0, &tmn); } __set_task_cpu(p, new_cpu); -- cgit v1.2.3 From e0b306fef90556233797d2e1747bd6a3ae35ea93 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Tue, 27 Nov 2012 23:28:59 -0200 Subject: time: export time information for KVM pvclock As suggested by John, export time data similarly to how its done by vsyscall support. This allows KVM to retrieve necessary information to implement vsyscall support in KVM guests. Acked-by: John Stultz Signed-off-by: Marcelo Tosatti --- include/linux/pvclock_gtod.h | 9 ++++++++ kernel/time/timekeeping.c | 50 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) create mode 100644 include/linux/pvclock_gtod.h (limited to 'kernel') diff --git a/include/linux/pvclock_gtod.h b/include/linux/pvclock_gtod.h new file mode 100644 index 000000000000..0ca75825b60d --- /dev/null +++ b/include/linux/pvclock_gtod.h @@ -0,0 +1,9 @@ +#ifndef _PVCLOCK_GTOD_H +#define _PVCLOCK_GTOD_H + +#include + +extern int pvclock_gtod_register_notifier(struct notifier_block *nb); +extern int pvclock_gtod_unregister_notifier(struct notifier_block *nb); + +#endif /* _PVCLOCK_GTOD_H */ diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index e424970bb562..69f5342e8d1c 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -21,6 +21,7 @@ #include #include #include +#include static struct timekeeper timekeeper; @@ -180,6 +181,54 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) return nsec + arch_gettimeoffset(); } +static RAW_NOTIFIER_HEAD(pvclock_gtod_chain); + +static void update_pvclock_gtod(struct timekeeper *tk) +{ + raw_notifier_call_chain(&pvclock_gtod_chain, 0, tk); +} + +/** + * pvclock_gtod_register_notifier - register a pvclock timedata update listener + * + * Must hold write on timekeeper.lock + */ +int pvclock_gtod_register_notifier(struct notifier_block *nb) +{ + struct timekeeper *tk = &timekeeper; + unsigned long flags; + int ret; + + write_seqlock_irqsave(&tk->lock, flags); + ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb); + /* update timekeeping data */ + update_pvclock_gtod(tk); + write_sequnlock_irqrestore(&tk->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier); + +/** + * pvclock_gtod_unregister_notifier - unregister a pvclock + * timedata update listener + * + * Must hold write on timekeeper.lock + */ +int pvclock_gtod_unregister_notifier(struct notifier_block *nb) +{ + struct timekeeper *tk = &timekeeper; + unsigned long flags; + int ret; + + write_seqlock_irqsave(&tk->lock, flags); + ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb); + write_sequnlock_irqrestore(&tk->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier); + /* must hold write on timekeeper.lock */ static void timekeeping_update(struct timekeeper *tk, bool clearntp) { @@ -188,6 +237,7 @@ static void timekeeping_update(struct timekeeper *tk, bool clearntp) ntp_clear(); } update_vsyscall(tk); + update_pvclock_gtod(tk); } /** -- cgit v1.2.3