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authorLinus Torvalds2016-10-03 13:39:00 -0700
committerLinus Torvalds2016-10-03 13:39:00 -0700
commitaf79ad2b1f337a00aa150b993635b10bc68dc842 (patch)
tree06abe1d9735b27a449443d7d29a9801f690080be /kernel/sched
parente606d81d2d9596ab2b4fd0dc052eea0485b7e8c2 (diff)
parent447976ef4fd09b1be88b316d1a81553f1aa7cd07 (diff)
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler changes from Ingo Molnar: "The main changes are: - irqtime accounting cleanups and enhancements. (Frederic Weisbecker) - schedstat debugging enhancements, make it more broadly runtime available. (Josh Poimboeuf) - More work on asymmetric topology/capacity scheduling. (Morten Rasmussen) - sched/wait fixes and cleanups. (Oleg Nesterov) - PELT (per entity load tracking) improvements. (Peter Zijlstra) - Rewrite and enhance select_idle_siblings(). (Peter Zijlstra) - sched/numa enhancements/fixes (Rik van Riel) - sched/cputime scalability improvements (Stanislaw Gruszka) - Load calculation arithmetics fixes. (Dietmar Eggemann) - sched/deadline enhancements (Tommaso Cucinotta) - Fix utilization accounting when switching to the SCHED_NORMAL policy. (Vincent Guittot) - ... plus misc cleanups and enhancements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits) sched/irqtime: Consolidate irqtime flushing code sched/irqtime: Consolidate accounting synchronization with u64_stats API u64_stats: Introduce IRQs disabled helpers sched/irqtime: Remove needless IRQs disablement on kcpustat update sched/irqtime: No need for preempt-safe accessors sched/fair: Fix min_vruntime tracking sched/debug: Add SCHED_WARN_ON() sched/core: Fix set_user_nice() sched/fair: Introduce set_curr_task() helper sched/core, ia64: Rename set_curr_task() sched/core: Fix incorrect utilization accounting when switching to fair class sched/core: Optimize SCHED_SMT sched/core: Rewrite and improve select_idle_siblings() sched/core: Replace sd_busy/nr_busy_cpus with sched_domain_shared sched/core: Introduce 'struct sched_domain_shared' sched/core: Restructure destroy_sched_domain() sched/core: Remove unused @cpu argument from destroy_sched_domain*() sched/wait: Introduce init_wait_entry() sched/wait: Avoid abort_exclusive_wait() in __wait_on_bit_lock() sched/wait: Avoid abort_exclusive_wait() in ___wait_event() ...
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c322
-rw-r--r--kernel/sched/cpudeadline.c153
-rw-r--r--kernel/sched/cpudeadline.h3
-rw-r--r--kernel/sched/cputime.c87
-rw-r--r--kernel/sched/deadline.c78
-rw-r--r--kernel/sched/debug.c103
-rw-r--r--kernel/sched/fair.c752
-rw-r--r--kernel/sched/idle_task.c4
-rw-r--r--kernel/sched/sched.h92
-rw-r--r--kernel/sched/stats.h24
-rw-r--r--kernel/sched/wait.c113
11 files changed, 1075 insertions, 656 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0a6a13c21c5a..fac6492f0b98 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1070,8 +1070,12 @@ static int migration_cpu_stop(void *data)
* holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
* we're holding p->pi_lock.
*/
- if (task_rq(p) == rq && task_on_rq_queued(p))
- rq = __migrate_task(rq, p, arg->dest_cpu);
+ if (task_rq(p) == rq) {
+ if (task_on_rq_queued(p))
+ rq = __migrate_task(rq, p, arg->dest_cpu);
+ else
+ p->wake_cpu = arg->dest_cpu;
+ }
raw_spin_unlock(&rq->lock);
raw_spin_unlock(&p->pi_lock);
@@ -1112,10 +1116,10 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
p->sched_class->set_cpus_allowed(p, new_mask);
- if (running)
- p->sched_class->set_curr_task(rq);
if (queued)
enqueue_task(rq, p, ENQUEUE_RESTORE);
+ if (running)
+ set_curr_task(rq, p);
}
/*
@@ -1272,7 +1276,7 @@ static void __migrate_swap_task(struct task_struct *p, int cpu)
/*
* Task isn't running anymore; make it appear like we migrated
* it before it went to sleep. This means on wakeup we make the
- * previous cpu our targer instead of where it really is.
+ * previous cpu our target instead of where it really is.
*/
p->wake_cpu = cpu;
}
@@ -1636,23 +1640,25 @@ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
static void
ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
{
-#ifdef CONFIG_SCHEDSTATS
- struct rq *rq = this_rq();
+ struct rq *rq;
-#ifdef CONFIG_SMP
- int this_cpu = smp_processor_id();
+ if (!schedstat_enabled())
+ return;
+
+ rq = this_rq();
- if (cpu == this_cpu) {
- schedstat_inc(rq, ttwu_local);
- schedstat_inc(p, se.statistics.nr_wakeups_local);
+#ifdef CONFIG_SMP
+ if (cpu == rq->cpu) {
+ schedstat_inc(rq->ttwu_local);
+ schedstat_inc(p->se.statistics.nr_wakeups_local);
} else {
struct sched_domain *sd;
- schedstat_inc(p, se.statistics.nr_wakeups_remote);
+ schedstat_inc(p->se.statistics.nr_wakeups_remote);
rcu_read_lock();
- for_each_domain(this_cpu, sd) {
+ for_each_domain(rq->cpu, sd) {
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
- schedstat_inc(sd, ttwu_wake_remote);
+ schedstat_inc(sd->ttwu_wake_remote);
break;
}
}
@@ -1660,17 +1666,14 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
}
if (wake_flags & WF_MIGRATED)
- schedstat_inc(p, se.statistics.nr_wakeups_migrate);
-
+ schedstat_inc(p->se.statistics.nr_wakeups_migrate);
#endif /* CONFIG_SMP */
- schedstat_inc(rq, ttwu_count);
- schedstat_inc(p, se.statistics.nr_wakeups);
+ schedstat_inc(rq->ttwu_count);
+ schedstat_inc(p->se.statistics.nr_wakeups);
if (wake_flags & WF_SYNC)
- schedstat_inc(p, se.statistics.nr_wakeups_sync);
-
-#endif /* CONFIG_SCHEDSTATS */
+ schedstat_inc(p->se.statistics.nr_wakeups_sync);
}
static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
@@ -2091,8 +2094,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
ttwu_queue(p, cpu, wake_flags);
stat:
- if (schedstat_enabled())
- ttwu_stat(p, cpu, wake_flags);
+ ttwu_stat(p, cpu, wake_flags);
out:
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
@@ -2102,6 +2104,7 @@ out:
/**
* try_to_wake_up_local - try to wake up a local task with rq lock held
* @p: the thread to be awakened
+ * @cookie: context's cookie for pinning
*
* Put @p on the run-queue if it's not already there. The caller must
* ensure that this_rq() is locked, @p is bound to this_rq() and not
@@ -2140,8 +2143,7 @@ static void try_to_wake_up_local(struct task_struct *p, struct pin_cookie cookie
ttwu_activate(rq, p, ENQUEUE_WAKEUP);
ttwu_do_wakeup(rq, p, 0, cookie);
- if (schedstat_enabled())
- ttwu_stat(p, smp_processor_id(), 0);
+ ttwu_stat(p, smp_processor_id(), 0);
out:
raw_spin_unlock(&p->pi_lock);
}
@@ -3199,6 +3201,9 @@ static inline void preempt_latency_stop(int val) { }
*/
static noinline void __schedule_bug(struct task_struct *prev)
{
+ /* Save this before calling printk(), since that will clobber it */
+ unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
+
if (oops_in_progress)
return;
@@ -3209,13 +3214,12 @@ static noinline void __schedule_bug(struct task_struct *prev)
print_modules();
if (irqs_disabled())
print_irqtrace_events(prev);
-#ifdef CONFIG_DEBUG_PREEMPT
- if (in_atomic_preempt_off()) {
+ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+ && in_atomic_preempt_off()) {
pr_err("Preemption disabled at:");
- print_ip_sym(current->preempt_disable_ip);
+ print_ip_sym(preempt_disable_ip);
pr_cont("\n");
}
-#endif
if (panic_on_warn)
panic("scheduling while atomic\n");
@@ -3241,7 +3245,7 @@ static inline void schedule_debug(struct task_struct *prev)
profile_hit(SCHED_PROFILING, __builtin_return_address(0));
- schedstat_inc(this_rq(), sched_count);
+ schedstat_inc(this_rq()->sched_count);
}
/*
@@ -3334,17 +3338,6 @@ static void __sched notrace __schedule(bool preempt)
rq = cpu_rq(cpu);
prev = rq->curr;
- /*
- * do_exit() calls schedule() with preemption disabled as an exception;
- * however we must fix that up, otherwise the next task will see an
- * inconsistent (higher) preempt count.
- *
- * It also avoids the below schedule_debug() test from complaining
- * about this.
- */
- if (unlikely(prev->state == TASK_DEAD))
- preempt_enable_no_resched_notrace();
-
schedule_debug(prev);
if (sched_feat(HRTICK))
@@ -3412,6 +3405,33 @@ static void __sched notrace __schedule(bool preempt)
}
STACK_FRAME_NON_STANDARD(__schedule); /* switch_to() */
+void __noreturn do_task_dead(void)
+{
+ /*
+ * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
+ * when the following two conditions become true.
+ * - There is race condition of mmap_sem (It is acquired by
+ * exit_mm()), and
+ * - SMI occurs before setting TASK_RUNINNG.
+ * (or hypervisor of virtual machine switches to other guest)
+ * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
+ *
+ * To avoid it, we have to wait for releasing tsk->pi_lock which
+ * is held by try_to_wake_up()
+ */
+ smp_mb();
+ raw_spin_unlock_wait(&current->pi_lock);
+
+ /* causes final put_task_struct in finish_task_switch(). */
+ __set_current_state(TASK_DEAD);
+ current->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
+ __schedule(false);
+ BUG();
+ /* Avoid "noreturn function does return". */
+ for (;;)
+ cpu_relax(); /* For when BUG is null */
+}
+
static inline void sched_submit_work(struct task_struct *tsk)
{
if (!tsk->state || tsk_is_pi_blocked(tsk))
@@ -3694,10 +3714,10 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
p->prio = prio;
- if (running)
- p->sched_class->set_curr_task(rq);
if (queued)
enqueue_task(rq, p, queue_flag);
+ if (running)
+ set_curr_task(rq, p);
check_class_changed(rq, p, prev_class, oldprio);
out_unlock:
@@ -3711,7 +3731,8 @@ out_unlock:
void set_user_nice(struct task_struct *p, long nice)
{
- int old_prio, delta, queued;
+ bool queued, running;
+ int old_prio, delta;
struct rq_flags rf;
struct rq *rq;
@@ -3733,8 +3754,11 @@ void set_user_nice(struct task_struct *p, long nice)
goto out_unlock;
}
queued = task_on_rq_queued(p);
+ running = task_current(rq, p);
if (queued)
dequeue_task(rq, p, DEQUEUE_SAVE);
+ if (running)
+ put_prev_task(rq, p);
p->static_prio = NICE_TO_PRIO(nice);
set_load_weight(p);
@@ -3751,6 +3775,8 @@ void set_user_nice(struct task_struct *p, long nice)
if (delta < 0 || (delta > 0 && task_running(rq, p)))
resched_curr(rq);
}
+ if (running)
+ set_curr_task(rq, p);
out_unlock:
task_rq_unlock(rq, p, &rf);
}
@@ -4250,8 +4276,6 @@ change:
prev_class = p->sched_class;
__setscheduler(rq, p, attr, pi);
- if (running)
- p->sched_class->set_curr_task(rq);
if (queued) {
/*
* We enqueue to tail when the priority of a task is
@@ -4262,6 +4286,8 @@ change:
enqueue_task(rq, p, queue_flags);
}
+ if (running)
+ set_curr_task(rq, p);
check_class_changed(rq, p, prev_class, oldprio);
preempt_disable(); /* avoid rq from going away on us */
@@ -4853,7 +4879,7 @@ SYSCALL_DEFINE0(sched_yield)
{
struct rq *rq = this_rq_lock();
- schedstat_inc(rq, yld_count);
+ schedstat_inc(rq->yld_count);
current->sched_class->yield_task(rq);
/*
@@ -4870,6 +4896,7 @@ SYSCALL_DEFINE0(sched_yield)
return 0;
}
+#ifndef CONFIG_PREEMPT
int __sched _cond_resched(void)
{
if (should_resched(0)) {
@@ -4879,6 +4906,7 @@ int __sched _cond_resched(void)
return 0;
}
EXPORT_SYMBOL(_cond_resched);
+#endif
/*
* __cond_resched_lock() - if a reschedule is pending, drop the given lock,
@@ -5004,7 +5032,7 @@ again:
yielded = curr->sched_class->yield_to_task(rq, p, preempt);
if (yielded) {
- schedstat_inc(rq, yld_count);
+ schedstat_inc(rq->yld_count);
/*
* Make p's CPU reschedule; pick_next_entity takes care of
* fairness.
@@ -5424,10 +5452,10 @@ void sched_setnuma(struct task_struct *p, int nid)
p->numa_preferred_nid = nid;
- if (running)
- p->sched_class->set_curr_task(rq);
if (queued)
enqueue_task(rq, p, ENQUEUE_RESTORE);
+ if (running)
+ set_curr_task(rq, p);
task_rq_unlock(rq, p, &rf);
}
#endif /* CONFIG_NUMA_BALANCING */
@@ -5724,6 +5752,8 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu)
}
}
#else /* !CONFIG_SCHED_DEBUG */
+
+# define sched_debug_enabled 0
# define sched_domain_debug(sd, cpu) do { } while (0)
static inline bool sched_debug(void)
{
@@ -5742,6 +5772,7 @@ static int sd_degenerate(struct sched_domain *sd)
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
SD_SHARE_CPUCAPACITY |
+ SD_ASYM_CPUCAPACITY |
SD_SHARE_PKG_RESOURCES |
SD_SHARE_POWERDOMAIN)) {
if (sd->groups != sd->groups->next)
@@ -5772,6 +5803,7 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
SD_BALANCE_NEWIDLE |
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
+ SD_ASYM_CPUCAPACITY |
SD_SHARE_CPUCAPACITY |
SD_SHARE_PKG_RESOURCES |
SD_PREFER_SIBLING |
@@ -5916,10 +5948,8 @@ static void free_sched_groups(struct sched_group *sg, int free_sgc)
} while (sg != first);
}
-static void free_sched_domain(struct rcu_head *rcu)
+static void destroy_sched_domain(struct sched_domain *sd)
{
- struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
-
/*
* If its an overlapping domain it has private groups, iterate and
* nuke them all.
@@ -5930,18 +5960,26 @@ static void free_sched_domain(struct rcu_head *rcu)
kfree(sd->groups->sgc);
kfree(sd->groups);
}
+ if (sd->shared && atomic_dec_and_test(&sd->shared->ref))
+ kfree(sd->shared);
kfree(sd);
}
-static void destroy_sched_domain(struct sched_domain *sd, int cpu)
+static void destroy_sched_domains_rcu(struct rcu_head *rcu)
{
- call_rcu(&sd->rcu, free_sched_domain);
+ struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);
+
+ while (sd) {
+ struct sched_domain *parent = sd->parent;
+ destroy_sched_domain(sd);
+ sd = parent;
+ }
}
-static void destroy_sched_domains(struct sched_domain *sd, int cpu)
+static void destroy_sched_domains(struct sched_domain *sd)
{
- for (; sd; sd = sd->parent)
- destroy_sched_domain(sd, cpu);
+ if (sd)
+ call_rcu(&sd->rcu, destroy_sched_domains_rcu);
}
/*
@@ -5956,14 +5994,14 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu)
DEFINE_PER_CPU(struct sched_domain *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_size);
DEFINE_PER_CPU(int, sd_llc_id);
+DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
DEFINE_PER_CPU(struct sched_domain *, sd_numa);
-DEFINE_PER_CPU(struct sched_domain *, sd_busy);
DEFINE_PER_CPU(struct sched_domain *, sd_asym);
static void update_top_cache_domain(int cpu)
{
+ struct sched_domain_shared *sds = NULL;
struct sched_domain *sd;
- struct sched_domain *busy_sd = NULL;
int id = cpu;
int size = 1;
@@ -5971,13 +6009,13 @@ static void update_top_cache_domain(int cpu)
if (sd) {
id = cpumask_first(sched_domain_span(sd));
size = cpumask_weight(sched_domain_span(sd));
- busy_sd = sd->parent; /* sd_busy */
+ sds = sd->shared;
}
- rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd);
rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
per_cpu(sd_llc_size, cpu) = size;
per_cpu(sd_llc_id, cpu) = id;
+ rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
sd = lowest_flag_domain(cpu, SD_NUMA);
rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
@@ -6013,7 +6051,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
*/
if (parent->flags & SD_PREFER_SIBLING)
tmp->flags |= SD_PREFER_SIBLING;
- destroy_sched_domain(parent, cpu);
+ destroy_sched_domain(parent);
} else
tmp = tmp->parent;
}
@@ -6021,7 +6059,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
if (sd && sd_degenerate(sd)) {
tmp = sd;
sd = sd->parent;
- destroy_sched_domain(tmp, cpu);
+ destroy_sched_domain(tmp);
if (sd)
sd->child = NULL;
}
@@ -6031,7 +6069,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
rq_attach_root(rq, rd);
tmp = rq->sd;
rcu_assign_pointer(rq->sd, sd);
- destroy_sched_domains(tmp, cpu);
+ destroy_sched_domains(tmp);
update_top_cache_domain(cpu);
}
@@ -6274,7 +6312,6 @@ static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
return;
update_group_capacity(sd, cpu);
- atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight);
}
/*
@@ -6362,6 +6399,9 @@ static void claim_allocations(int cpu, struct sched_domain *sd)
WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
*per_cpu_ptr(sdd->sd, cpu) = NULL;
+ if (atomic_read(&(*per_cpu_ptr(sdd->sds, cpu))->ref))
+ *per_cpu_ptr(sdd->sds, cpu) = NULL;
+
if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
*per_cpu_ptr(sdd->sg, cpu) = NULL;
@@ -6381,26 +6421,37 @@ static int sched_domains_curr_level;
/*
* SD_flags allowed in topology descriptions.
*
- * SD_SHARE_CPUCAPACITY - describes SMT topologies
- * SD_SHARE_PKG_RESOURCES - describes shared caches
- * SD_NUMA - describes NUMA topologies
- * SD_SHARE_POWERDOMAIN - describes shared power domain
+ * These flags are purely descriptive of the topology and do not prescribe
+ * behaviour. Behaviour is artificial and mapped in the below sd_init()
+ * function:
+ *
+ * SD_SHARE_CPUCAPACITY - describes SMT topologies
+ * SD_SHARE_PKG_RESOURCES - describes shared caches
+ * SD_NUMA - describes NUMA topologies
+ * SD_SHARE_POWERDOMAIN - describes shared power domain
+ * SD_ASYM_CPUCAPACITY - describes mixed capacity topologies
+ *
+ * Odd one out, which beside describing the topology has a quirk also
+ * prescribes the desired behaviour that goes along with it:
*
- * Odd one out:
- * SD_ASYM_PACKING - describes SMT quirks
+ * SD_ASYM_PACKING - describes SMT quirks
*/
#define TOPOLOGY_SD_FLAGS \
(SD_SHARE_CPUCAPACITY | \
SD_SHARE_PKG_RESOURCES | \
SD_NUMA | \
SD_ASYM_PACKING | \
+ SD_ASYM_CPUCAPACITY | \
SD_SHARE_POWERDOMAIN)
static struct sched_domain *
-sd_init(struct sched_domain_topology_level *tl, int cpu)
+sd_init(struct sched_domain_topology_level *tl,
+ const struct cpumask *cpu_map,
+ struct sched_domain *child, int cpu)
{
- struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
- int sd_weight, sd_flags = 0;
+ struct sd_data *sdd = &tl->data;
+ struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
+ int sd_id, sd_weight, sd_flags = 0;
#ifdef CONFIG_NUMA
/*
@@ -6449,15 +6500,26 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
.smt_gain = 0,
.max_newidle_lb_cost = 0,
.next_decay_max_lb_cost = jiffies,
+ .child = child,
#ifdef CONFIG_SCHED_DEBUG
.name = tl->name,
#endif
};
+ cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
+ sd_id = cpumask_first(sched_domain_span(sd));
+
/*
* Convert topological properties into behaviour.
*/
+ if (sd->flags & SD_ASYM_CPUCAPACITY) {
+ struct sched_domain *t = sd;
+
+ for_each_lower_domain(t)
+ t->flags |= SD_BALANCE_WAKE;
+ }
+
if (sd->flags & SD_SHARE_CPUCAPACITY) {
sd->flags |= SD_PREFER_SIBLING;
sd->imbalance_pct = 110;
@@ -6489,7 +6551,17 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
sd->idle_idx = 1;
}
- sd->private = &tl->data;
+ /*
+ * For all levels sharing cache; connect a sched_domain_shared
+ * instance.
+ */
+ if (sd->flags & SD_SHARE_PKG_RESOURCES) {
+ sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
+ atomic_inc(&sd->shared->ref);
+ atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
+ }
+
+ sd->private = sdd;
return sd;
}
@@ -6516,6 +6588,9 @@ static struct sched_domain_topology_level *sched_domain_topology =
void set_sched_topology(struct sched_domain_topology_level *tl)
{
+ if (WARN_ON_ONCE(sched_smp_initialized))
+ return;
+
sched_domain_topology = tl;
}
@@ -6796,6 +6871,10 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
if (!sdd->sd)
return -ENOMEM;
+ sdd->sds = alloc_percpu(struct sched_domain_shared *);
+ if (!sdd->sds)
+ return -ENOMEM;
+
sdd->sg = alloc_percpu(struct sched_group *);
if (!sdd->sg)
return -ENOMEM;
@@ -6806,6 +6885,7 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
for_each_cpu(j, cpu_map) {
struct sched_domain *sd;
+ struct sched_domain_shared *sds;
struct sched_group *sg;
struct sched_group_capacity *sgc;
@@ -6816,6 +6896,13 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
*per_cpu_ptr(sdd->sd, j) = sd;
+ sds = kzalloc_node(sizeof(struct sched_domain_shared),
+ GFP_KERNEL, cpu_to_node(j));
+ if (!sds)
+ return -ENOMEM;
+
+ *per_cpu_ptr(sdd->sds, j) = sds;
+
sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
GFP_KERNEL, cpu_to_node(j));
if (!sg)
@@ -6855,6 +6942,8 @@ static void __sdt_free(const struct cpumask *cpu_map)
kfree(*per_cpu_ptr(sdd->sd, j));
}
+ if (sdd->sds)
+ kfree(*per_cpu_ptr(sdd->sds, j));
if (sdd->sg)
kfree(*per_cpu_ptr(sdd->sg, j));
if (sdd->sgc)
@@ -6862,6 +6951,8 @@ static void __sdt_free(const struct cpumask *cpu_map)
}
free_percpu(sdd->sd);
sdd->sd = NULL;
+ free_percpu(sdd->sds);
+ sdd->sds = NULL;
free_percpu(sdd->sg);
sdd->sg = NULL;
free_percpu(sdd->sgc);
@@ -6873,16 +6964,12 @@ struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
const struct cpumask *cpu_map, struct sched_domain_attr *attr,
struct sched_domain *child, int cpu)
{
- struct sched_domain *sd = sd_init(tl, cpu);
- if (!sd)
- return child;
+ struct sched_domain *sd = sd_init(tl, cpu_map, child, cpu);
- cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
if (child) {
sd->level = child->level + 1;
sched_domain_level_max = max(sched_domain_level_max, sd->level);
child->parent = sd;
- sd->child = child;
if (!cpumask_subset(sched_domain_span(child),
sched_domain_span(sd))) {
@@ -6913,6 +7000,7 @@ static int build_sched_domains(const struct cpumask *cpu_map,
enum s_alloc alloc_state;
struct sched_domain *sd;
struct s_data d;
+ struct rq *rq = NULL;
int i, ret = -ENOMEM;
alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
@@ -6963,11 +7051,22 @@ static int build_sched_domains(const struct cpumask *cpu_map,
/* Attach the domains */
rcu_read_lock();
for_each_cpu(i, cpu_map) {
+ rq = cpu_rq(i);
sd = *per_cpu_ptr(d.sd, i);
+
+ /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
+ if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
+ WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
+
cpu_attach_domain(sd, d.rd, i);
}
rcu_read_unlock();
+ if (rq && sched_debug_enabled) {
+ pr_info("span: %*pbl (max cpu_capacity = %lu)\n",
+ cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
+ }
+
ret = 0;
error:
__free_domain_allocs(&d, alloc_state, cpu_map);
@@ -7326,6 +7425,22 @@ int sched_cpu_dying(unsigned int cpu)
}
#endif
+#ifdef CONFIG_SCHED_SMT
+DEFINE_STATIC_KEY_FALSE(sched_smt_present);
+
+static void sched_init_smt(void)
+{
+ /*
+ * We've enumerated all CPUs and will assume that if any CPU
+ * has SMT siblings, CPU0 will too.
+ */
+ if (cpumask_weight(cpu_smt_mask(0)) > 1)
+ static_branch_enable(&sched_smt_present);
+}
+#else
+static inline void sched_init_smt(void) { }
+#endif
+
void __init sched_init_smp(void)
{
cpumask_var_t non_isolated_cpus;
@@ -7355,6 +7470,9 @@ void __init sched_init_smp(void)
init_sched_rt_class();
init_sched_dl_class();
+
+ sched_init_smt();
+
sched_smp_initialized = true;
}
@@ -7392,6 +7510,7 @@ static struct kmem_cache *task_group_cache __read_mostly;
#endif
DECLARE_PER_CPU(cpumask_var_t, load_balance_mask);
+DECLARE_PER_CPU(cpumask_var_t, select_idle_mask);
void __init sched_init(void)
{
@@ -7428,6 +7547,8 @@ void __init sched_init(void)
for_each_possible_cpu(i) {
per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node(
cpumask_size(), GFP_KERNEL, cpu_to_node(i));
+ per_cpu(select_idle_mask, i) = (cpumask_var_t)kzalloc_node(
+ cpumask_size(), GFP_KERNEL, cpu_to_node(i));
}
#endif /* CONFIG_CPUMASK_OFFSTACK */
@@ -7530,10 +7651,6 @@ void __init sched_init(void)
set_load_weight(&init_task);
-#ifdef CONFIG_PREEMPT_NOTIFIERS
- INIT_HLIST_HEAD(&init_task.preempt_notifiers);
-#endif
-
/*
* The boot idle thread does lazy MMU switching as well:
*/
@@ -7541,11 +7658,6 @@ void __init sched_init(void)
enter_lazy_tlb(&init_mm, current);
/*
- * During early bootup we pretend to be a normal task:
- */
- current->sched_class = &fair_sched_class;
-
- /*
* Make us the idle thread. Technically, schedule() should not be
* called from this thread, however somewhere below it might be,
* but because we are the idle thread, we just pick up running again
@@ -7599,6 +7711,7 @@ EXPORT_SYMBOL(__might_sleep);
void ___might_sleep(const char *file, int line, int preempt_offset)
{
static unsigned long prev_jiffy; /* ratelimiting */
+ unsigned long preempt_disable_ip;
rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
@@ -7609,6 +7722,9 @@ void ___might_sleep(const char *file, int line, int preempt_offset)
return;
prev_jiffy = jiffies;
+ /* Save this before calling printk(), since that will clobber it */
+ preempt_disable_ip = get_preempt_disable_ip(current);
+
printk(KERN_ERR
"BUG: sleeping function called from invalid context at %s:%d\n",
file, line);
@@ -7623,14 +7739,14 @@ void ___might_sleep(const char *file, int line, int preempt_offset)
debug_show_held_locks(current);
if (irqs_disabled())
print_irqtrace_events(current);
-#ifdef CONFIG_DEBUG_PREEMPT
- if (!preempt_count_equals(preempt_offset)) {
+ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+ && !preempt_count_equals(preempt_offset)) {
pr_err("Preemption disabled at:");
- print_ip_sym(current->preempt_disable_ip);
+ print_ip_sym(preempt_disable_ip);
pr_cont("\n");
}
-#endif
dump_stack();
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
}
EXPORT_SYMBOL(___might_sleep);
#endif
@@ -7651,12 +7767,10 @@ void normalize_rt_tasks(void)
if (p->flags & PF_KTHREAD)
continue;
- p->se.exec_start = 0;
-#ifdef CONFIG_SCHEDSTATS
- p->se.statistics.wait_start = 0;
- p->se.statistics.sleep_start = 0;
- p->se.statistics.block_start = 0;
-#endif
+ p->se.exec_start = 0;
+ schedstat_set(p->se.statistics.wait_start, 0);
+ schedstat_set(p->se.statistics.sleep_start, 0);
+ schedstat_set(p->se.statistics.block_start, 0);
if (!dl_task(p) && !rt_task(p)) {
/*
@@ -7717,7 +7831,7 @@ struct task_struct *curr_task(int cpu)
*
* ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
*/
-void set_curr_task(int cpu, struct task_struct *p)
+void ia64_set_curr_task(int cpu, struct task_struct *p)
{
cpu_curr(cpu) = p;
}
@@ -7848,10 +7962,10 @@ void sched_move_task(struct task_struct *tsk)
sched_change_group(tsk, TASK_MOVE_GROUP);
- if (unlikely(running))
- tsk->sched_class->set_curr_task(rq);
if (queued)
enqueue_task(rq, tsk, ENQUEUE_RESTORE | ENQUEUE_MOVE);
+ if (unlikely(running))
+ set_curr_task(rq, tsk);
task_rq_unlock(rq, tsk, &rf);
}
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index d4184498c9f5..e73119013c53 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -31,56 +31,81 @@ static inline int right_child(int i)
return (i << 1) + 2;
}
-static void cpudl_exchange(struct cpudl *cp, int a, int b)
+static void cpudl_heapify_down(struct cpudl *cp, int idx)
{
- int cpu_a = cp->elements[a].cpu, cpu_b = cp->elements[b].cpu;
+ int l, r, largest;
- swap(cp->elements[a].cpu, cp->elements[b].cpu);
- swap(cp->elements[a].dl , cp->elements[b].dl );
+ int orig_cpu = cp->elements[idx].cpu;
+ u64 orig_dl = cp->elements[idx].dl;
- swap(cp->elements[cpu_a].idx, cp->elements[cpu_b].idx);
-}
-
-static void cpudl_heapify(struct cpudl *cp, int idx)
-{
- int l, r, largest;
+ if (left_child(idx) >= cp->size)
+ return;
/* adapted from lib/prio_heap.c */
while(1) {
+ u64 largest_dl;
l = left_child(idx);
r = right_child(idx);
largest = idx;
+ largest_dl = orig_dl;
- if ((l < cp->size) && dl_time_before(cp->elements[idx].dl,
- cp->elements[l].dl))
+ if ((l < cp->size) && dl_time_before(orig_dl,
+ cp->elements[l].dl)) {
largest = l;
- if ((r < cp->size) && dl_time_before(cp->elements[largest].dl,
- cp->elements[r].dl))
+ largest_dl = cp->elements[l].dl;
+ }
+ if ((r < cp->size) && dl_time_before(largest_dl,
+ cp->elements[r].dl))
largest = r;
+
if (largest == idx)
break;
- /* Push idx down the heap one level and bump one up */
- cpudl_exchange(cp, largest, idx);
+ /* pull largest child onto idx */
+ cp->elements[idx].cpu = cp->elements[largest].cpu;
+ cp->elements[idx].dl = cp->elements[largest].dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
idx = largest;
}
+ /* actual push down of saved original values orig_* */
+ cp->elements[idx].cpu = orig_cpu;
+ cp->elements[idx].dl = orig_dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
}
-static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl)
+static void cpudl_heapify_up(struct cpudl *cp, int idx)
{
- WARN_ON(idx == IDX_INVALID || !cpu_present(idx));
+ int p;
- if (dl_time_before(new_dl, cp->elements[idx].dl)) {
- cp->elements[idx].dl = new_dl;
- cpudl_heapify(cp, idx);
- } else {
- cp->elements[idx].dl = new_dl;
- while (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
- cp->elements[idx].dl)) {
- cpudl_exchange(cp, idx, parent(idx));
- idx = parent(idx);
- }
- }
+ int orig_cpu = cp->elements[idx].cpu;
+ u64 orig_dl = cp->elements[idx].dl;
+
+ if (idx == 0)
+ return;
+
+ do {
+ p = parent(idx);
+ if (dl_time_before(orig_dl, cp->elements[p].dl))
+ break;
+ /* pull parent onto idx */
+ cp->elements[idx].cpu = cp->elements[p].cpu;
+ cp->elements[idx].dl = cp->elements[p].dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
+ idx = p;
+ } while (idx != 0);
+ /* actual push up of saved original values orig_* */
+ cp->elements[idx].cpu = orig_cpu;
+ cp->elements[idx].dl = orig_dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
+}
+
+static void cpudl_heapify(struct cpudl *cp, int idx)
+{
+ if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
+ cp->elements[idx].dl))
+ cpudl_heapify_up(cp, idx);
+ else
+ cpudl_heapify_down(cp, idx);
}
static inline int cpudl_maximum(struct cpudl *cp)
@@ -120,16 +145,15 @@ out:
}
/*
- * cpudl_set - update the cpudl max-heap
+ * cpudl_clear - remove a cpu from the cpudl max-heap
* @cp: the cpudl max-heap context
* @cpu: the target cpu
- * @dl: the new earliest deadline for this cpu
*
* Notes: assumes cpu_rq(cpu)->lock is locked
*
* Returns: (void)
*/
-void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
+void cpudl_clear(struct cpudl *cp, int cpu)
{
int old_idx, new_cpu;
unsigned long flags;
@@ -137,47 +161,60 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
WARN_ON(!cpu_present(cpu));
raw_spin_lock_irqsave(&cp->lock, flags);
+
old_idx = cp->elements[cpu].idx;
- if (!is_valid) {
- /* remove item */
- if (old_idx == IDX_INVALID) {
- /*
- * Nothing to remove if old_idx was invalid.
- * This could happen if a rq_offline_dl is
- * called for a CPU without -dl tasks running.
- */
- goto out;
- }
+ if (old_idx == IDX_INVALID) {
+ /*
+ * Nothing to remove if old_idx was invalid.
+ * This could happen if a rq_offline_dl is
+ * called for a CPU without -dl tasks running.
+ */
+ } else {
new_cpu = cp->elements[cp->size - 1].cpu;
cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
cp->elements[old_idx].cpu = new_cpu;
cp->size--;
cp->elements[new_cpu].idx = old_idx;
cp->elements[cpu].idx = IDX_INVALID;
- while (old_idx > 0 && dl_time_before(
- cp->elements[parent(old_idx)].dl,
- cp->elements[old_idx].dl)) {
- cpudl_exchange(cp, old_idx, parent(old_idx));
- old_idx = parent(old_idx);
- }
- cpumask_set_cpu(cpu, cp->free_cpus);
- cpudl_heapify(cp, old_idx);
+ cpudl_heapify(cp, old_idx);
- goto out;
+ cpumask_set_cpu(cpu, cp->free_cpus);
}
+ raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
+/*
+ * cpudl_set - update the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target cpu
+ * @dl: the new earliest deadline for this cpu
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
+{
+ int old_idx;
+ unsigned long flags;
+ WARN_ON(!cpu_present(cpu));
+
+ raw_spin_lock_irqsave(&cp->lock, flags);
+
+ old_idx = cp->elements[cpu].idx;
if (old_idx == IDX_INVALID) {
- cp->size++;
- cp->elements[cp->size - 1].dl = dl;
- cp->elements[cp->size - 1].cpu = cpu;
- cp->elements[cpu].idx = cp->size - 1;
- cpudl_change_key(cp, cp->size - 1, dl);
+ int new_idx = cp->size++;
+ cp->elements[new_idx].dl = dl;
+ cp->elements[new_idx].cpu = cpu;
+ cp->elements[cpu].idx = new_idx;
+ cpudl_heapify_up(cp, new_idx);
cpumask_clear_cpu(cpu, cp->free_cpus);
} else {
- cpudl_change_key(cp, old_idx, dl);
+ cp->elements[old_idx].dl = dl;
+ cpudl_heapify(cp, old_idx);
}
-out:
raw_spin_unlock_irqrestore(&cp->lock, flags);
}
diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h
index fcbdf83fed7e..f7da8c55bba0 100644
--- a/kernel/sched/cpudeadline.h
+++ b/kernel/sched/cpudeadline.h
@@ -23,7 +23,8 @@ struct cpudl {
#ifdef CONFIG_SMP
int cpudl_find(struct cpudl *cp, struct task_struct *p,
struct cpumask *later_mask);
-void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid);
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl);
+void cpudl_clear(struct cpudl *cp, int cpu);
int cpudl_init(struct cpudl *cp);
void cpudl_set_freecpu(struct cpudl *cp, int cpu);
void cpudl_clear_freecpu(struct cpudl *cp, int cpu);
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index a846cf89eb96..5ebee3164e64 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -23,10 +23,8 @@
* task when irq is in progress while we read rq->clock. That is a worthy
* compromise in place of having locks on each irq in account_system_time.
*/
-DEFINE_PER_CPU(u64, cpu_hardirq_time);
-DEFINE_PER_CPU(u64, cpu_softirq_time);
+DEFINE_PER_CPU(struct irqtime, cpu_irqtime);
-static DEFINE_PER_CPU(u64, irq_start_time);
static int sched_clock_irqtime;
void enable_sched_clock_irqtime(void)
@@ -39,16 +37,13 @@ void disable_sched_clock_irqtime(void)
sched_clock_irqtime = 0;
}
-#ifndef CONFIG_64BIT
-DEFINE_PER_CPU(seqcount_t, irq_time_seq);
-#endif /* CONFIG_64BIT */
-
/*
* Called before incrementing preempt_count on {soft,}irq_enter
* and before decrementing preempt_count on {soft,}irq_exit.
*/
void irqtime_account_irq(struct task_struct *curr)
{
+ struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
s64 delta;
int cpu;
@@ -56,10 +51,10 @@ void irqtime_account_irq(struct task_struct *curr)
return;
cpu = smp_processor_id();
- delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
- __this_cpu_add(irq_start_time, delta);
+ delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
+ irqtime->irq_start_time += delta;
- irq_time_write_begin();
+ u64_stats_update_begin(&irqtime->sync);
/*
* We do not account for softirq time from ksoftirqd here.
* We want to continue accounting softirq time to ksoftirqd thread
@@ -67,42 +62,36 @@ void irqtime_account_irq(struct task_struct *curr)
* that do not consume any time, but still wants to run.
*/
if (hardirq_count())
- __this_cpu_add(cpu_hardirq_time, delta);
+ irqtime->hardirq_time += delta;
else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
- __this_cpu_add(cpu_softirq_time, delta);
+ irqtime->softirq_time += delta;
- irq_time_write_end();
+ u64_stats_update_end(&irqtime->sync);
}
EXPORT_SYMBOL_GPL(irqtime_account_irq);
-static cputime_t irqtime_account_hi_update(cputime_t maxtime)
+static cputime_t irqtime_account_update(u64 irqtime, int idx, cputime_t maxtime)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;
- unsigned long flags;
cputime_t irq_cputime;
- local_irq_save(flags);
- irq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time)) -
- cpustat[CPUTIME_IRQ];
+ irq_cputime = nsecs_to_cputime64(irqtime) - cpustat[idx];
irq_cputime = min(irq_cputime, maxtime);
- cpustat[CPUTIME_IRQ] += irq_cputime;
- local_irq_restore(flags);
+ cpustat[idx] += irq_cputime;
+
return irq_cputime;
}
-static cputime_t irqtime_account_si_update(cputime_t maxtime)
+static cputime_t irqtime_account_hi_update(cputime_t maxtime)
{
- u64 *cpustat = kcpustat_this_cpu->cpustat;
- unsigned long flags;
- cputime_t softirq_cputime;
+ return irqtime_account_update(__this_cpu_read(cpu_irqtime.hardirq_time),
+ CPUTIME_IRQ, maxtime);
+}
- local_irq_save(flags);
- softirq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time)) -
- cpustat[CPUTIME_SOFTIRQ];
- softirq_cputime = min(softirq_cputime, maxtime);
- cpustat[CPUTIME_SOFTIRQ] += softirq_cputime;
- local_irq_restore(flags);
- return softirq_cputime;
+static cputime_t irqtime_account_si_update(cputime_t maxtime)
+{
+ return irqtime_account_update(__this_cpu_read(cpu_irqtime.softirq_time),
+ CPUTIME_SOFTIRQ, maxtime);
}
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
@@ -295,6 +284,9 @@ static inline cputime_t account_other_time(cputime_t max)
{
cputime_t accounted;
+ /* Shall be converted to a lockdep-enabled lightweight check */
+ WARN_ON_ONCE(!irqs_disabled());
+
accounted = steal_account_process_time(max);
if (accounted < max)
@@ -306,6 +298,26 @@ static inline cputime_t account_other_time(cputime_t max)
return accounted;
}
+#ifdef CONFIG_64BIT
+static inline u64 read_sum_exec_runtime(struct task_struct *t)
+{
+ return t->se.sum_exec_runtime;
+}
+#else
+static u64 read_sum_exec_runtime(struct task_struct *t)
+{
+ u64 ns;
+ struct rq_flags rf;
+ struct rq *rq;
+
+ rq = task_rq_lock(t, &rf);
+ ns = t->se.sum_exec_runtime;
+ task_rq_unlock(rq, t, &rf);
+
+ return ns;
+}
+#endif
+
/*
* Accumulate raw cputime values of dead tasks (sig->[us]time) and live
* tasks (sum on group iteration) belonging to @tsk's group.
@@ -318,6 +330,17 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
unsigned int seq, nextseq;
unsigned long flags;
+ /*
+ * Update current task runtime to account pending time since last
+ * scheduler action or thread_group_cputime() call. This thread group
+ * might have other running tasks on different CPUs, but updating
+ * their runtime can affect syscall performance, so we skip account
+ * those pending times and rely only on values updated on tick or
+ * other scheduler action.
+ */
+ if (same_thread_group(current, tsk))
+ (void) task_sched_runtime(current);
+
rcu_read_lock();
/* Attempt a lockless read on the first round. */
nextseq = 0;
@@ -332,7 +355,7 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
task_cputime(t, &utime, &stime);
times->utime += utime;
times->stime += stime;
- times->sum_exec_runtime += task_sched_runtime(t);
+ times->sum_exec_runtime += read_sum_exec_runtime(t);
}
/* If lockless access failed, take the lock. */
nextseq = 1;
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 974779656999..37e2449186c4 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -243,10 +243,8 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p)
{
struct rq *later_rq = NULL;
- bool fallback = false;
later_rq = find_lock_later_rq(p, rq);
-
if (!later_rq) {
int cpu;
@@ -254,7 +252,6 @@ static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p
* If we cannot preempt any rq, fall back to pick any
* online cpu.
*/
- fallback = true;
cpu = cpumask_any_and(cpu_active_mask, tsk_cpus_allowed(p));
if (cpu >= nr_cpu_ids) {
/*
@@ -274,16 +271,7 @@ static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p
double_lock_balance(rq, later_rq);
}
- /*
- * By now the task is replenished and enqueued; migrate it.
- */
- deactivate_task(rq, p, 0);
set_task_cpu(p, later_rq->cpu);
- activate_task(later_rq, p, 0);
-
- if (!fallback)
- resched_curr(later_rq);
-
double_unlock_balance(later_rq, rq);
return later_rq;
@@ -346,12 +334,12 @@ static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
* one, and to (try to!) reconcile itself with its own scheduling
* parameters.
*/
-static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
- struct sched_dl_entity *pi_se)
+static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
{
struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
struct rq *rq = rq_of_dl_rq(dl_rq);
+ WARN_ON(dl_se->dl_boosted);
WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
/*
@@ -367,8 +355,8 @@ static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
* future; in fact, we must consider execution overheads (time
* spent on hardirq context, etc.).
*/
- dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
- dl_se->runtime = pi_se->dl_runtime;
+ dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline;
+ dl_se->runtime = dl_se->dl_runtime;
}
/*
@@ -641,29 +629,31 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
goto unlock;
}
- enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
- if (dl_task(rq->curr))
- check_preempt_curr_dl(rq, p, 0);
- else
- resched_curr(rq);
-
#ifdef CONFIG_SMP
- /*
- * Perform balancing operations here; after the replenishments. We
- * cannot drop rq->lock before this, otherwise the assertion in
- * start_dl_timer() about not missing updates is not true.
- *
- * If we find that the rq the task was on is no longer available, we
- * need to select a new rq.
- *
- * XXX figure out if select_task_rq_dl() deals with offline cpus.
- */
if (unlikely(!rq->online)) {
+ /*
+ * If the runqueue is no longer available, migrate the
+ * task elsewhere. This necessarily changes rq.
+ */
lockdep_unpin_lock(&rq->lock, rf.cookie);
rq = dl_task_offline_migration(rq, p);
rf.cookie = lockdep_pin_lock(&rq->lock);
+
+ /*
+ * Now that the task has been migrated to the new RQ and we
+ * have that locked, proceed as normal and enqueue the task
+ * there.
+ */
}
+#endif
+
+ enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
+ if (dl_task(rq->curr))
+ check_preempt_curr_dl(rq, p, 0);
+ else
+ resched_curr(rq);
+#ifdef CONFIG_SMP
/*
* Queueing this task back might have overloaded rq, check if we need
* to kick someone away.
@@ -797,7 +787,7 @@ static void inc_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
if (dl_rq->earliest_dl.curr == 0 ||
dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
dl_rq->earliest_dl.curr = deadline;
- cpudl_set(&rq->rd->cpudl, rq->cpu, deadline, 1);
+ cpudl_set(&rq->rd->cpudl, rq->cpu, deadline);
}
}
@@ -812,14 +802,14 @@ static void dec_dl_deadline(struct dl_rq *dl_rq, u64 deadline)
if (!dl_rq->dl_nr_running) {
dl_rq->earliest_dl.curr = 0;
dl_rq->earliest_dl.next = 0;
- cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
+ cpudl_clear(&rq->rd->cpudl, rq->cpu);
} else {
struct rb_node *leftmost = dl_rq->rb_leftmost;
struct sched_dl_entity *entry;
entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
dl_rq->earliest_dl.curr = entry->deadline;
- cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline, 1);
+ cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline);
}
}
@@ -1670,7 +1660,7 @@ static void rq_online_dl(struct rq *rq)
cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
if (rq->dl.dl_nr_running > 0)
- cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr, 1);
+ cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr);
}
/* Assumes rq->lock is held */
@@ -1679,7 +1669,7 @@ static void rq_offline_dl(struct rq *rq)
if (rq->dl.overloaded)
dl_clear_overload(rq);
- cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
+ cpudl_clear(&rq->rd->cpudl, rq->cpu);
cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
}
@@ -1722,10 +1712,20 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
*/
static void switched_to_dl(struct rq *rq, struct task_struct *p)
{
+
+ /* If p is not queued we will update its parameters at next wakeup. */
+ if (!task_on_rq_queued(p))
+ return;
+
+ /*
+ * If p is boosted we already updated its params in
+ * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH),
+ * p's deadline being now already after rq_clock(rq).
+ */
if (dl_time_before(p->dl.deadline, rq_clock(rq)))
- setup_new_dl_entity(&p->dl, &p->dl);
+ setup_new_dl_entity(&p->dl);
- if (task_on_rq_queued(p) && rq->curr != p) {
+ if (rq->curr != p) {
#ifdef CONFIG_SMP
if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
queue_push_tasks(rq);
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 2a0a9995256d..13935886a471 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -369,8 +369,12 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
#define P(F) \
SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)F)
+#define P_SCHEDSTAT(F) \
+ SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)schedstat_val(F))
#define PN(F) \
SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
+#define PN_SCHEDSTAT(F) \
+ SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)schedstat_val(F)))
if (!se)
return;
@@ -378,26 +382,27 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
PN(se->exec_start);
PN(se->vruntime);
PN(se->sum_exec_runtime);
-#ifdef CONFIG_SCHEDSTATS
if (schedstat_enabled()) {
- PN(se->statistics.wait_start);
- PN(se->statistics.sleep_start);
- PN(se->statistics.block_start);
- PN(se->statistics.sleep_max);
- PN(se->statistics.block_max);
- PN(se->statistics.exec_max);
- PN(se->statistics.slice_max);
- PN(se->statistics.wait_max);
- PN(se->statistics.wait_sum);
- P(se->statistics.wait_count);
+ PN_SCHEDSTAT(se->statistics.wait_start);
+ PN_SCHEDSTAT(se->statistics.sleep_start);
+ PN_SCHEDSTAT(se->statistics.block_start);
+ PN_SCHEDSTAT(se->statistics.sleep_max);
+ PN_SCHEDSTAT(se->statistics.block_max);
+ PN_SCHEDSTAT(se->statistics.exec_max);
+ PN_SCHEDSTAT(se->statistics.slice_max);
+ PN_SCHEDSTAT(se->statistics.wait_max);
+ PN_SCHEDSTAT(se->statistics.wait_sum);
+ P_SCHEDSTAT(se->statistics.wait_count);
}
-#endif
P(se->load.weight);
#ifdef CONFIG_SMP
P(se->avg.load_avg);
P(se->avg.util_avg);
#endif
+
+#undef PN_SCHEDSTAT
#undef PN
+#undef P_SCHEDSTAT
#undef P
}
#endif
@@ -429,9 +434,9 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
p->prio);
SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld",
- SPLIT_NS(schedstat_val(p, se.statistics.wait_sum)),
+ SPLIT_NS(schedstat_val_or_zero(p->se.statistics.wait_sum)),
SPLIT_NS(p->se.sum_exec_runtime),
- SPLIT_NS(schedstat_val(p, se.statistics.sum_sleep_runtime)));
+ SPLIT_NS(schedstat_val_or_zero(p->se.statistics.sum_sleep_runtime)));
#ifdef CONFIG_NUMA_BALANCING
SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
@@ -626,9 +631,7 @@ do { \
#undef P64
#endif
-#ifdef CONFIG_SCHEDSTATS
-#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
-
+#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, schedstat_val(rq->n));
if (schedstat_enabled()) {
P(yld_count);
P(sched_count);
@@ -636,9 +639,8 @@ do { \
P(ttwu_count);
P(ttwu_local);
}
-
#undef P
-#endif
+
spin_lock_irqsave(&sched_debug_lock, flags);
print_cfs_stats(m, cpu);
print_rt_stats(m, cpu);
@@ -868,10 +870,14 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
SEQ_printf(m, "%-45s:%21Ld\n", #F, (long long)F)
#define P(F) \
SEQ_printf(m, "%-45s:%21Ld\n", #F, (long long)p->F)
+#define P_SCHEDSTAT(F) \
+ SEQ_printf(m, "%-45s:%21Ld\n", #F, (long long)schedstat_val(p->F))
#define __PN(F) \
SEQ_printf(m, "%-45s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)F))
#define PN(F) \
SEQ_printf(m, "%-45s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)p->F))
+#define PN_SCHEDSTAT(F) \
+ SEQ_printf(m, "%-45s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)schedstat_val(p->F)))
PN(se.exec_start);
PN(se.vruntime);
@@ -881,37 +887,36 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
P(se.nr_migrations);
-#ifdef CONFIG_SCHEDSTATS
if (schedstat_enabled()) {
u64 avg_atom, avg_per_cpu;
- PN(se.statistics.sum_sleep_runtime);
- PN(se.statistics.wait_start);
- PN(se.statistics.sleep_start);
- PN(se.statistics.block_start);
- PN(se.statistics.sleep_max);
- PN(se.statistics.block_max);
- PN(se.statistics.exec_max);
- PN(se.statistics.slice_max);
- PN(se.statistics.wait_max);
- PN(se.statistics.wait_sum);
- P(se.statistics.wait_count);
- PN(se.statistics.iowait_sum);
- P(se.statistics.iowait_count);
- P(se.statistics.nr_migrations_cold);
- P(se.statistics.nr_failed_migrations_affine);
- P(se.statistics.nr_failed_migrations_running);
- P(se.statistics.nr_failed_migrations_hot);
- P(se.statistics.nr_forced_migrations);
- P(se.statistics.nr_wakeups);
- P(se.statistics.nr_wakeups_sync);
- P(se.statistics.nr_wakeups_migrate);
- P(se.statistics.nr_wakeups_local);
- P(se.statistics.nr_wakeups_remote);
- P(se.statistics.nr_wakeups_affine);
- P(se.statistics.nr_wakeups_affine_attempts);
- P(se.statistics.nr_wakeups_passive);
- P(se.statistics.nr_wakeups_idle);
+ PN_SCHEDSTAT(se.statistics.sum_sleep_runtime);
+ PN_SCHEDSTAT(se.statistics.wait_start);
+ PN_SCHEDSTAT(se.statistics.sleep_start);
+ PN_SCHEDSTAT(se.statistics.block_start);
+ PN_SCHEDSTAT(se.statistics.sleep_max);
+ PN_SCHEDSTAT(se.statistics.block_max);
+ PN_SCHEDSTAT(se.statistics.exec_max);
+ PN_SCHEDSTAT(se.statistics.slice_max);
+ PN_SCHEDSTAT(se.statistics.wait_max);
+ PN_SCHEDSTAT(se.statistics.wait_sum);
+ P_SCHEDSTAT(se.statistics.wait_count);
+ PN_SCHEDSTAT(se.statistics.iowait_sum);
+ P_SCHEDSTAT(se.statistics.iowait_count);
+ P_SCHEDSTAT(se.statistics.nr_migrations_cold);
+ P_SCHEDSTAT(se.statistics.nr_failed_migrations_affine);
+ P_SCHEDSTAT(se.statistics.nr_failed_migrations_running);
+ P_SCHEDSTAT(se.statistics.nr_failed_migrations_hot);
+ P_SCHEDSTAT(se.statistics.nr_forced_migrations);
+ P_SCHEDSTAT(se.statistics.nr_wakeups);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_sync);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_migrate);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_local);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_remote);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_affine);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_affine_attempts);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_passive);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_idle);
avg_atom = p->se.sum_exec_runtime;
if (nr_switches)
@@ -930,7 +935,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
__PN(avg_atom);
__PN(avg_per_cpu);
}
-#endif
+
__P(nr_switches);
SEQ_printf(m, "%-45s:%21Ld\n",
"nr_voluntary_switches", (long long)p->nvcsw);
@@ -947,8 +952,10 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
#endif
P(policy);
P(prio);
+#undef PN_SCHEDSTAT
#undef PN
#undef __PN
+#undef P_SCHEDSTAT
#undef P
#undef __P
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a5cd07b25aa1..502e95a6e927 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -114,6 +114,12 @@ unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
#endif
+/*
+ * The margin used when comparing utilization with CPU capacity:
+ * util * 1024 < capacity * margin
+ */
+unsigned int capacity_margin = 1280; /* ~20% */
+
static inline void update_load_add(struct load_weight *lw, unsigned long inc)
{
lw->weight += inc;
@@ -256,9 +262,7 @@ static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
static inline struct task_struct *task_of(struct sched_entity *se)
{
-#ifdef CONFIG_SCHED_DEBUG
- WARN_ON_ONCE(!entity_is_task(se));
-#endif
+ SCHED_WARN_ON(!entity_is_task(se));
return container_of(se, struct task_struct, se);
}
@@ -456,17 +460,23 @@ static inline int entity_before(struct sched_entity *a,
static void update_min_vruntime(struct cfs_rq *cfs_rq)
{
+ struct sched_entity *curr = cfs_rq->curr;
+
u64 vruntime = cfs_rq->min_vruntime;
- if (cfs_rq->curr)
- vruntime = cfs_rq->curr->vruntime;
+ if (curr) {
+ if (curr->on_rq)
+ vruntime = curr->vruntime;
+ else
+ curr = NULL;
+ }
if (cfs_rq->rb_leftmost) {
struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost,
struct sched_entity,
run_node);
- if (!cfs_rq->curr)
+ if (!curr)
vruntime = se->vruntime;
else
vruntime = min_vruntime(vruntime, se->vruntime);
@@ -656,7 +666,7 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
}
#ifdef CONFIG_SMP
-static int select_idle_sibling(struct task_struct *p, int cpu);
+static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
static unsigned long task_h_load(struct task_struct *p);
/*
@@ -726,7 +736,6 @@ void post_init_entity_util_avg(struct sched_entity *se)
struct sched_avg *sa = &se->avg;
long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2;
u64 now = cfs_rq_clock_task(cfs_rq);
- int tg_update;
if (cap > 0) {
if (cfs_rq->avg.util_avg != 0) {
@@ -759,10 +768,9 @@ void post_init_entity_util_avg(struct sched_entity *se)
}
}
- tg_update = update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_cfs_rq_load_avg(now, cfs_rq, false);
attach_entity_load_avg(cfs_rq, se);
- if (tg_update)
- update_tg_load_avg(cfs_rq, false);
+ update_tg_load_avg(cfs_rq, false);
}
#else /* !CONFIG_SMP */
@@ -799,7 +807,7 @@ static void update_curr(struct cfs_rq *cfs_rq)
max(delta_exec, curr->statistics.exec_max));
curr->sum_exec_runtime += delta_exec;
- schedstat_add(cfs_rq, exec_clock, delta_exec);
+ schedstat_add(cfs_rq->exec_clock, delta_exec);
curr->vruntime += calc_delta_fair(delta_exec, curr);
update_min_vruntime(cfs_rq);
@@ -820,26 +828,34 @@ static void update_curr_fair(struct rq *rq)
update_curr(cfs_rq_of(&rq->curr->se));
}
-#ifdef CONFIG_SCHEDSTATS
static inline void
update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- u64 wait_start = rq_clock(rq_of(cfs_rq));
+ u64 wait_start, prev_wait_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ wait_start = rq_clock(rq_of(cfs_rq));
+ prev_wait_start = schedstat_val(se->statistics.wait_start);
if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) &&
- likely(wait_start > se->statistics.wait_start))
- wait_start -= se->statistics.wait_start;
+ likely(wait_start > prev_wait_start))
+ wait_start -= prev_wait_start;
- se->statistics.wait_start = wait_start;
+ schedstat_set(se->statistics.wait_start, wait_start);
}
-static void
+static inline void
update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct task_struct *p;
u64 delta;
- delta = rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start;
+ if (!schedstat_enabled())
+ return;
+
+ delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start);
if (entity_is_task(se)) {
p = task_of(se);
@@ -849,35 +865,114 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
* time stamp can be adjusted to accumulate wait time
* prior to migration.
*/
- se->statistics.wait_start = delta;
+ schedstat_set(se->statistics.wait_start, delta);
return;
}
trace_sched_stat_wait(p, delta);
}
- se->statistics.wait_max = max(se->statistics.wait_max, delta);
- se->statistics.wait_count++;
- se->statistics.wait_sum += delta;
- se->statistics.wait_start = 0;
+ schedstat_set(se->statistics.wait_max,
+ max(schedstat_val(se->statistics.wait_max), delta));
+ schedstat_inc(se->statistics.wait_count);
+ schedstat_add(se->statistics.wait_sum, delta);
+ schedstat_set(se->statistics.wait_start, 0);
+}
+
+static inline void
+update_stats_enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ struct task_struct *tsk = NULL;
+ u64 sleep_start, block_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ sleep_start = schedstat_val(se->statistics.sleep_start);
+ block_start = schedstat_val(se->statistics.block_start);
+
+ if (entity_is_task(se))
+ tsk = task_of(se);
+
+ if (sleep_start) {
+ u64 delta = rq_clock(rq_of(cfs_rq)) - sleep_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.sleep_max)))
+ schedstat_set(se->statistics.sleep_max, delta);
+
+ schedstat_set(se->statistics.sleep_start, 0);
+ schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ account_scheduler_latency(tsk, delta >> 10, 1);
+ trace_sched_stat_sleep(tsk, delta);
+ }
+ }
+ if (block_start) {
+ u64 delta = rq_clock(rq_of(cfs_rq)) - block_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.block_max)))
+ schedstat_set(se->statistics.block_max, delta);
+
+ schedstat_set(se->statistics.block_start, 0);
+ schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ if (tsk->in_iowait) {
+ schedstat_add(se->statistics.iowait_sum, delta);
+ schedstat_inc(se->statistics.iowait_count);
+ trace_sched_stat_iowait(tsk, delta);
+ }
+
+ trace_sched_stat_blocked(tsk, delta);
+
+ /*
+ * Blocking time is in units of nanosecs, so shift by
+ * 20 to get a milliseconds-range estimation of the
+ * amount of time that the task spent sleeping:
+ */
+ if (unlikely(prof_on == SLEEP_PROFILING)) {
+ profile_hits(SLEEP_PROFILING,
+ (void *)get_wchan(tsk),
+ delta >> 20);
+ }
+ account_scheduler_latency(tsk, delta >> 10, 0);
+ }
+ }
}
/*
* Task is being enqueued - update stats:
*/
static inline void
-update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
+ if (!schedstat_enabled())
+ return;
+
/*
* Are we enqueueing a waiting task? (for current tasks
* a dequeue/enqueue event is a NOP)
*/
if (se != cfs_rq->curr)
update_stats_wait_start(cfs_rq, se);
+
+ if (flags & ENQUEUE_WAKEUP)
+ update_stats_enqueue_sleeper(cfs_rq, se);
}
static inline void
update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
+
+ if (!schedstat_enabled())
+ return;
+
/*
* Mark the end of the wait period if dequeueing a
* waiting task:
@@ -885,40 +980,18 @@ update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
if (se != cfs_rq->curr)
update_stats_wait_end(cfs_rq, se);
- if (flags & DEQUEUE_SLEEP) {
- if (entity_is_task(se)) {
- struct task_struct *tsk = task_of(se);
+ if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
+ struct task_struct *tsk = task_of(se);
- if (tsk->state & TASK_INTERRUPTIBLE)
- se->statistics.sleep_start = rq_clock(rq_of(cfs_rq));
- if (tsk->state & TASK_UNINTERRUPTIBLE)
- se->statistics.block_start = rq_clock(rq_of(cfs_rq));
- }
+ if (tsk->state & TASK_INTERRUPTIBLE)
+ schedstat_set(se->statistics.sleep_start,
+ rq_clock(rq_of(cfs_rq)));
+ if (tsk->state & TASK_UNINTERRUPTIBLE)
+ schedstat_set(se->statistics.block_start,
+ rq_clock(rq_of(cfs_rq)));
}
-
-}
-#else
-static inline void
-update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-}
-
-static inline void
-update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-}
-
-static inline void
-update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
}
-static inline void
-update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
-{
-}
-#endif
-
/*
* We are picking a new current task - update its stats:
*/
@@ -1513,8 +1586,16 @@ balance:
* One idle CPU per node is evaluated for a task numa move.
* Call select_idle_sibling to maybe find a better one.
*/
- if (!cur)
- env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu);
+ if (!cur) {
+ /*
+ * select_idle_siblings() uses an per-cpu cpumask that
+ * can be used from IRQ context.
+ */
+ local_irq_disable();
+ env->dst_cpu = select_idle_sibling(env->p, env->src_cpu,
+ env->dst_cpu);
+ local_irq_enable();
+ }
assign:
task_numa_assign(env, cur, imp);
@@ -2292,7 +2373,7 @@ void task_numa_work(struct callback_head *work)
unsigned long nr_pte_updates = 0;
long pages, virtpages;
- WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work));
+ SCHED_WARN_ON(p != container_of(work, struct task_struct, numa_work));
work->next = work; /* protect against double add */
/*
@@ -2803,9 +2884,21 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa,
}
#ifdef CONFIG_FAIR_GROUP_SCHED
-/*
- * Updating tg's load_avg is necessary before update_cfs_share (which is done)
- * and effective_load (which is not done because it is too costly).
+/**
+ * update_tg_load_avg - update the tg's load avg
+ * @cfs_rq: the cfs_rq whose avg changed
+ * @force: update regardless of how small the difference
+ *
+ * This function 'ensures': tg->load_avg := \Sum tg->cfs_rq[]->avg.load.
+ * However, because tg->load_avg is a global value there are performance
+ * considerations.
+ *
+ * In order to avoid having to look at the other cfs_rq's, we use a
+ * differential update where we store the last value we propagated. This in
+ * turn allows skipping updates if the differential is 'small'.
+ *
+ * Updating tg's load_avg is necessary before update_cfs_share() (which is
+ * done) and effective_load() (which is not done because it is too costly).
*/
static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force)
{
@@ -2925,10 +3018,10 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
*
* cfs_rq->avg is used for task_h_load() and update_cfs_share() for example.
*
- * Returns true if the load decayed or we removed utilization. It is expected
- * that one calls update_tg_load_avg() on this condition, but after you've
- * modified the cfs_rq avg (attach/detach), such that we propagate the new
- * avg up.
+ * Returns true if the load decayed or we removed load.
+ *
+ * Since both these conditions indicate a changed cfs_rq->avg.load we should
+ * call update_tg_load_avg() when this function returns true.
*/
static inline int
update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
@@ -3174,68 +3267,6 @@ static inline int idle_balance(struct rq *rq)
#endif /* CONFIG_SMP */
-static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-#ifdef CONFIG_SCHEDSTATS
- struct task_struct *tsk = NULL;
-
- if (entity_is_task(se))
- tsk = task_of(se);
-
- if (se->statistics.sleep_start) {
- u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.sleep_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->statistics.sleep_max))
- se->statistics.sleep_max = delta;
-
- se->statistics.sleep_start = 0;
- se->statistics.sum_sleep_runtime += delta;
-
- if (tsk) {
- account_scheduler_latency(tsk, delta >> 10, 1);
- trace_sched_stat_sleep(tsk, delta);
- }
- }
- if (se->statistics.block_start) {
- u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.block_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->statistics.block_max))
- se->statistics.block_max = delta;
-
- se->statistics.block_start = 0;
- se->statistics.sum_sleep_runtime += delta;
-
- if (tsk) {
- if (tsk->in_iowait) {
- se->statistics.iowait_sum += delta;
- se->statistics.iowait_count++;
- trace_sched_stat_iowait(tsk, delta);
- }
-
- trace_sched_stat_blocked(tsk, delta);
-
- /*
- * Blocking time is in units of nanosecs, so shift by
- * 20 to get a milliseconds-range estimation of the
- * amount of time that the task spent sleeping:
- */
- if (unlikely(prof_on == SLEEP_PROFILING)) {
- profile_hits(SLEEP_PROFILING,
- (void *)get_wchan(tsk),
- delta >> 20);
- }
- account_scheduler_latency(tsk, delta >> 10, 0);
- }
- }
-#endif
-}
-
static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
#ifdef CONFIG_SCHED_DEBUG
@@ -3245,7 +3276,7 @@ static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
d = -d;
if (d > 3*sysctl_sched_latency)
- schedstat_inc(cfs_rq, nr_spread_over);
+ schedstat_inc(cfs_rq->nr_spread_over);
#endif
}
@@ -3362,17 +3393,12 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
account_entity_enqueue(cfs_rq, se);
update_cfs_shares(cfs_rq);
- if (flags & ENQUEUE_WAKEUP) {
+ if (flags & ENQUEUE_WAKEUP)
place_entity(cfs_rq, se, 0);
- if (schedstat_enabled())
- enqueue_sleeper(cfs_rq, se);
- }
check_schedstat_required();
- if (schedstat_enabled()) {
- update_stats_enqueue(cfs_rq, se);
- check_spread(cfs_rq, se);
- }
+ update_stats_enqueue(cfs_rq, se, flags);
+ check_spread(cfs_rq, se);
if (!curr)
__enqueue_entity(cfs_rq, se);
se->on_rq = 1;
@@ -3439,8 +3465,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
update_curr(cfs_rq);
dequeue_entity_load_avg(cfs_rq, se);
- if (schedstat_enabled())
- update_stats_dequeue(cfs_rq, se, flags);
+ update_stats_dequeue(cfs_rq, se, flags);
clear_buddies(cfs_rq, se);
@@ -3450,9 +3475,10 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
account_entity_dequeue(cfs_rq, se);
/*
- * Normalize the entity after updating the min_vruntime because the
- * update can refer to the ->curr item and we need to reflect this
- * movement in our normalized position.
+ * Normalize after update_curr(); which will also have moved
+ * min_vruntime if @se is the one holding it back. But before doing
+ * update_min_vruntime() again, which will discount @se's position and
+ * can move min_vruntime forward still more.
*/
if (!(flags & DEQUEUE_SLEEP))
se->vruntime -= cfs_rq->min_vruntime;
@@ -3460,8 +3486,16 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
/* return excess runtime on last dequeue */
return_cfs_rq_runtime(cfs_rq);
- update_min_vruntime(cfs_rq);
update_cfs_shares(cfs_rq);
+
+ /*
+ * Now advance min_vruntime if @se was the entity holding it back,
+ * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be
+ * put back on, and if we advance min_vruntime, we'll be placed back
+ * further than we started -- ie. we'll be penalized.
+ */
+ if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)
+ update_min_vruntime(cfs_rq);
}
/*
@@ -3514,25 +3548,25 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
* a CPU. So account for the time it spent waiting on the
* runqueue.
*/
- if (schedstat_enabled())
- update_stats_wait_end(cfs_rq, se);
+ update_stats_wait_end(cfs_rq, se);
__dequeue_entity(cfs_rq, se);
update_load_avg(se, 1);
}
update_stats_curr_start(cfs_rq, se);
cfs_rq->curr = se;
-#ifdef CONFIG_SCHEDSTATS
+
/*
* Track our maximum slice length, if the CPU's load is at
* least twice that of our own weight (i.e. dont track it
* when there are only lesser-weight tasks around):
*/
if (schedstat_enabled() && rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
- se->statistics.slice_max = max(se->statistics.slice_max,
- se->sum_exec_runtime - se->prev_sum_exec_runtime);
+ schedstat_set(se->statistics.slice_max,
+ max((u64)schedstat_val(se->statistics.slice_max),
+ se->sum_exec_runtime - se->prev_sum_exec_runtime));
}
-#endif
+
se->prev_sum_exec_runtime = se->sum_exec_runtime;
}
@@ -3611,13 +3645,10 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
/* throttle cfs_rqs exceeding runtime */
check_cfs_rq_runtime(cfs_rq);
- if (schedstat_enabled()) {
- check_spread(cfs_rq, prev);
- if (prev->on_rq)
- update_stats_wait_start(cfs_rq, prev);
- }
+ check_spread(cfs_rq, prev);
if (prev->on_rq) {
+ update_stats_wait_start(cfs_rq, prev);
/* Put 'current' back into the tree. */
__enqueue_entity(cfs_rq, prev);
/* in !on_rq case, update occurred at dequeue */
@@ -4447,9 +4478,9 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- WARN_ON(task_rq(p) != rq);
+ SCHED_WARN_ON(task_rq(p) != rq);
- if (cfs_rq->nr_running > 1) {
+ if (rq->cfs.h_nr_running > 1) {
u64 slice = sched_slice(cfs_rq, se);
u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
s64 delta = slice - ran;
@@ -4604,6 +4635,11 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
}
#ifdef CONFIG_SMP
+
+/* Working cpumask for: load_balance, load_balance_newidle. */
+DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
+DEFINE_PER_CPU(cpumask_var_t, select_idle_mask);
+
#ifdef CONFIG_NO_HZ_COMMON
/*
* per rq 'load' arrray crap; XXX kill this.
@@ -5005,9 +5041,9 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
* wl = S * s'_i; see (2)
*/
if (W > 0 && w < W)
- wl = (w * (long)tg->shares) / W;
+ wl = (w * (long)scale_load_down(tg->shares)) / W;
else
- wl = tg->shares;
+ wl = scale_load_down(tg->shares);
/*
* Per the above, wl is the new se->load.weight value; since
@@ -5090,18 +5126,18 @@ static int wake_wide(struct task_struct *p)
return 1;
}
-static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
+static int wake_affine(struct sched_domain *sd, struct task_struct *p,
+ int prev_cpu, int sync)
{
s64 this_load, load;
s64 this_eff_load, prev_eff_load;
- int idx, this_cpu, prev_cpu;
+ int idx, this_cpu;
struct task_group *tg;
unsigned long weight;
int balanced;
idx = sd->wake_idx;
this_cpu = smp_processor_id();
- prev_cpu = task_cpu(p);
load = source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
@@ -5145,13 +5181,13 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
balanced = this_eff_load <= prev_eff_load;
- schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
+ schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts);
if (!balanced)
return 0;
- schedstat_inc(sd, ttwu_move_affine);
- schedstat_inc(p, se.statistics.nr_wakeups_affine);
+ schedstat_inc(sd->ttwu_move_affine);
+ schedstat_inc(p->se.statistics.nr_wakeups_affine);
return 1;
}
@@ -5227,6 +5263,10 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
int shallowest_idle_cpu = -1;
int i;
+ /* Check if we have any choice: */
+ if (group->group_weight == 1)
+ return cpumask_first(sched_group_cpus(group));
+
/* Traverse only the allowed CPUs */
for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
if (idle_cpu(i)) {
@@ -5264,64 +5304,237 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
}
/*
- * Try and locate an idle CPU in the sched_domain.
+ * Implement a for_each_cpu() variant that starts the scan at a given cpu
+ * (@start), and wraps around.
+ *
+ * This is used to scan for idle CPUs; such that not all CPUs looking for an
+ * idle CPU find the same CPU. The down-side is that tasks tend to cycle
+ * through the LLC domain.
+ *
+ * Especially tbench is found sensitive to this.
+ */
+
+static int cpumask_next_wrap(int n, const struct cpumask *mask, int start, int *wrapped)
+{
+ int next;
+
+again:
+ next = find_next_bit(cpumask_bits(mask), nr_cpumask_bits, n+1);
+
+ if (*wrapped) {
+ if (next >= start)
+ return nr_cpumask_bits;
+ } else {
+ if (next >= nr_cpumask_bits) {
+ *wrapped = 1;
+ n = -1;
+ goto again;
+ }
+ }
+
+ return next;
+}
+
+#define for_each_cpu_wrap(cpu, mask, start, wrap) \
+ for ((wrap) = 0, (cpu) = (start)-1; \
+ (cpu) = cpumask_next_wrap((cpu), (mask), (start), &(wrap)), \
+ (cpu) < nr_cpumask_bits; )
+
+#ifdef CONFIG_SCHED_SMT
+
+static inline void set_idle_cores(int cpu, int val)
+{
+ struct sched_domain_shared *sds;
+
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds)
+ WRITE_ONCE(sds->has_idle_cores, val);
+}
+
+static inline bool test_idle_cores(int cpu, bool def)
+{
+ struct sched_domain_shared *sds;
+
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds)
+ return READ_ONCE(sds->has_idle_cores);
+
+ return def;
+}
+
+/*
+ * Scans the local SMT mask to see if the entire core is idle, and records this
+ * information in sd_llc_shared->has_idle_cores.
+ *
+ * Since SMT siblings share all cache levels, inspecting this limited remote
+ * state should be fairly cheap.
*/
-static int select_idle_sibling(struct task_struct *p, int target)
+void __update_idle_core(struct rq *rq)
+{
+ int core = cpu_of(rq);
+ int cpu;
+
+ rcu_read_lock();
+ if (test_idle_cores(core, true))
+ goto unlock;
+
+ for_each_cpu(cpu, cpu_smt_mask(core)) {
+ if (cpu == core)
+ continue;
+
+ if (!idle_cpu(cpu))
+ goto unlock;
+ }
+
+ set_idle_cores(core, 1);
+unlock:
+ rcu_read_unlock();
+}
+
+/*
+ * Scan the entire LLC domain for idle cores; this dynamically switches off if
+ * there are no idle cores left in the system; tracked through
+ * sd_llc->shared->has_idle_cores and enabled through update_idle_core() above.
+ */
+static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask);
+ int core, cpu, wrap;
+
+ if (!static_branch_likely(&sched_smt_present))
+ return -1;
+
+ if (!test_idle_cores(target, false))
+ return -1;
+
+ cpumask_and(cpus, sched_domain_span(sd), tsk_cpus_allowed(p));
+
+ for_each_cpu_wrap(core, cpus, target, wrap) {
+ bool idle = true;
+
+ for_each_cpu(cpu, cpu_smt_mask(core)) {
+ cpumask_clear_cpu(cpu, cpus);
+ if (!idle_cpu(cpu))
+ idle = false;
+ }
+
+ if (idle)
+ return core;
+ }
+
+ /*
+ * Failed to find an idle core; stop looking for one.
+ */
+ set_idle_cores(target, 0);
+
+ return -1;
+}
+
+/*
+ * Scan the local SMT mask for idle CPUs.
+ */
+static int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ int cpu;
+
+ if (!static_branch_likely(&sched_smt_present))
+ return -1;
+
+ for_each_cpu(cpu, cpu_smt_mask(target)) {
+ if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+ continue;
+ if (idle_cpu(cpu))
+ return cpu;
+ }
+
+ return -1;
+}
+
+#else /* CONFIG_SCHED_SMT */
+
+static inline int select_idle_core(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ return -1;
+}
+
+static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ return -1;
+}
+
+#endif /* CONFIG_SCHED_SMT */
+
+/*
+ * Scan the LLC domain for idle CPUs; this is dynamically regulated by
+ * comparing the average scan cost (tracked in sd->avg_scan_cost) against the
+ * average idle time for this rq (as found in rq->avg_idle).
+ */
+static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int target)
+{
+ struct sched_domain *this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
+ u64 avg_idle = this_rq()->avg_idle;
+ u64 avg_cost = this_sd->avg_scan_cost;
+ u64 time, cost;
+ s64 delta;
+ int cpu, wrap;
+
+ /*
+ * Due to large variance we need a large fuzz factor; hackbench in
+ * particularly is sensitive here.
+ */
+ if ((avg_idle / 512) < avg_cost)
+ return -1;
+
+ time = local_clock();
+
+ for_each_cpu_wrap(cpu, sched_domain_span(sd), target, wrap) {
+ if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
+ continue;
+ if (idle_cpu(cpu))
+ break;
+ }
+
+ time = local_clock() - time;
+ cost = this_sd->avg_scan_cost;
+ delta = (s64)(time - cost) / 8;
+ this_sd->avg_scan_cost += delta;
+
+ return cpu;
+}
+
+/*
+ * Try and locate an idle core/thread in the LLC cache domain.
+ */
+static int select_idle_sibling(struct task_struct *p, int prev, int target)
{
struct sched_domain *sd;
- struct sched_group *sg;
- int i = task_cpu(p);
+ int i;
if (idle_cpu(target))
return target;
/*
- * If the prevous cpu is cache affine and idle, don't be stupid.
+ * If the previous cpu is cache affine and idle, don't be stupid.
*/
- if (i != target && cpus_share_cache(i, target) && idle_cpu(i))
- return i;
+ if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev))
+ return prev;
- /*
- * Otherwise, iterate the domains and find an eligible idle cpu.
- *
- * A completely idle sched group at higher domains is more
- * desirable than an idle group at a lower level, because lower
- * domains have smaller groups and usually share hardware
- * resources which causes tasks to contend on them, e.g. x86
- * hyperthread siblings in the lowest domain (SMT) can contend
- * on the shared cpu pipeline.
- *
- * However, while we prefer idle groups at higher domains
- * finding an idle cpu at the lowest domain is still better than
- * returning 'target', which we've already established, isn't
- * idle.
- */
sd = rcu_dereference(per_cpu(sd_llc, target));
- for_each_lower_domain(sd) {
- sg = sd->groups;
- do {
- if (!cpumask_intersects(sched_group_cpus(sg),
- tsk_cpus_allowed(p)))
- goto next;
-
- /* Ensure the entire group is idle */
- for_each_cpu(i, sched_group_cpus(sg)) {
- if (i == target || !idle_cpu(i))
- goto next;
- }
+ if (!sd)
+ return target;
+
+ i = select_idle_core(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
+
+ i = select_idle_cpu(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
+
+ i = select_idle_smt(p, sd, target);
+ if ((unsigned)i < nr_cpumask_bits)
+ return i;
- /*
- * It doesn't matter which cpu we pick, the
- * whole group is idle.
- */
- target = cpumask_first_and(sched_group_cpus(sg),
- tsk_cpus_allowed(p));
- goto done;
-next:
- sg = sg->next;
- } while (sg != sd->groups);
- }
-done:
return target;
}
@@ -5359,6 +5572,32 @@ static int cpu_util(int cpu)
return (util >= capacity) ? capacity : util;
}
+static inline int task_util(struct task_struct *p)
+{
+ return p->se.avg.util_avg;
+}
+
+/*
+ * Disable WAKE_AFFINE in the case where task @p doesn't fit in the
+ * capacity of either the waking CPU @cpu or the previous CPU @prev_cpu.
+ *
+ * In that case WAKE_AFFINE doesn't make sense and we'll let
+ * BALANCE_WAKE sort things out.
+ */
+static int wake_cap(struct task_struct *p, int cpu, int prev_cpu)
+{
+ long min_cap, max_cap;
+
+ min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu));
+ max_cap = cpu_rq(cpu)->rd->max_cpu_capacity;
+
+ /* Minimum capacity is close to max, no need to abort wake_affine */
+ if (max_cap - min_cap < max_cap >> 3)
+ return 0;
+
+ return min_cap * 1024 < task_util(p) * capacity_margin;
+}
+
/*
* select_task_rq_fair: Select target runqueue for the waking task in domains
* that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE,
@@ -5382,7 +5621,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (sd_flag & SD_BALANCE_WAKE) {
record_wakee(p);
- want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
+ want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu)
+ && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
}
rcu_read_lock();
@@ -5408,13 +5648,13 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (affine_sd) {
sd = NULL; /* Prefer wake_affine over balance flags */
- if (cpu != prev_cpu && wake_affine(affine_sd, p, sync))
+ if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync))
new_cpu = cpu;
}
if (!sd) {
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
- new_cpu = select_idle_sibling(p, new_cpu);
+ new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
} else while (sd) {
struct sched_group *group;
@@ -5938,7 +6178,7 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp
*
* The adjacency matrix of the resulting graph is given by:
*
- * log_2 n
+ * log_2 n
* A_i,j = \Union (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1) (6)
* k = 0
*
@@ -5984,7 +6224,7 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp
*
* [XXX write more on how we solve this.. _after_ merging pjt's patches that
* rewrite all of this once again.]
- */
+ */
static unsigned long __read_mostly max_load_balance_interval = HZ/10;
@@ -6132,7 +6372,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
int cpu;
- schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
+ schedstat_inc(p->se.statistics.nr_failed_migrations_affine);
env->flags |= LBF_SOME_PINNED;
@@ -6163,7 +6403,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
env->flags &= ~LBF_ALL_PINNED;
if (task_running(env->src_rq, p)) {
- schedstat_inc(p, se.statistics.nr_failed_migrations_running);
+ schedstat_inc(p->se.statistics.nr_failed_migrations_running);
return 0;
}
@@ -6180,13 +6420,13 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
if (tsk_cache_hot <= 0 ||
env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
if (tsk_cache_hot == 1) {
- schedstat_inc(env->sd, lb_hot_gained[env->idle]);
- schedstat_inc(p, se.statistics.nr_forced_migrations);
+ schedstat_inc(env->sd->lb_hot_gained[env->idle]);
+ schedstat_inc(p->se.statistics.nr_forced_migrations);
}
return 1;
}
- schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+ schedstat_inc(p->se.statistics.nr_failed_migrations_hot);
return 0;
}
@@ -6226,7 +6466,7 @@ static struct task_struct *detach_one_task(struct lb_env *env)
* so we can safely collect stats here rather than
* inside detach_tasks().
*/
- schedstat_inc(env->sd, lb_gained[env->idle]);
+ schedstat_inc(env->sd->lb_gained[env->idle]);
return p;
}
return NULL;
@@ -6318,7 +6558,7 @@ next:
* so we can safely collect detach_one_task() stats here rather
* than inside detach_one_task().
*/
- schedstat_add(env->sd, lb_gained[env->idle], detached);
+ schedstat_add(env->sd->lb_gained[env->idle], detached);
return detached;
}
@@ -6646,7 +6886,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
/*
* !SD_OVERLAP domains can assume that child groups
* span the current group.
- */
+ */
group = child->groups;
do {
@@ -7146,7 +7386,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
load_above_capacity = busiest->sum_nr_running * SCHED_CAPACITY_SCALE;
if (load_above_capacity > busiest->group_capacity) {
load_above_capacity -= busiest->group_capacity;
- load_above_capacity *= NICE_0_LOAD;
+ load_above_capacity *= scale_load_down(NICE_0_LOAD);
load_above_capacity /= busiest->group_capacity;
} else
load_above_capacity = ~0UL;
@@ -7353,9 +7593,6 @@ static struct rq *find_busiest_queue(struct lb_env *env,
*/
#define MAX_PINNED_INTERVAL 512
-/* Working cpumask for load_balance and load_balance_newidle. */
-DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
-
static int need_active_balance(struct lb_env *env)
{
struct sched_domain *sd = env->sd;
@@ -7459,7 +7696,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
cpumask_copy(cpus, cpu_active_mask);
- schedstat_inc(sd, lb_count[idle]);
+ schedstat_inc(sd->lb_count[idle]);
redo:
if (!should_we_balance(&env)) {
@@ -7469,19 +7706,19 @@ redo:
group = find_busiest_group(&env);
if (!group) {
- schedstat_inc(sd, lb_nobusyg[idle]);
+ schedstat_inc(sd->lb_nobusyg[idle]);
goto out_balanced;
}
busiest = find_busiest_queue(&env, group);
if (!busiest) {
- schedstat_inc(sd, lb_nobusyq[idle]);
+ schedstat_inc(sd->lb_nobusyq[idle]);
goto out_balanced;
}
BUG_ON(busiest == env.dst_rq);
- schedstat_add(sd, lb_imbalance[idle], env.imbalance);
+ schedstat_add(sd->lb_imbalance[idle], env.imbalance);
env.src_cpu = busiest->cpu;
env.src_rq = busiest;
@@ -7588,7 +7825,7 @@ more_balance:
}
if (!ld_moved) {
- schedstat_inc(sd, lb_failed[idle]);
+ schedstat_inc(sd->lb_failed[idle]);
/*
* Increment the failure counter only on periodic balance.
* We do not want newidle balance, which can be very
@@ -7671,7 +7908,7 @@ out_all_pinned:
* we can't migrate them. Let the imbalance flag set so parent level
* can try to migrate them.
*/
- schedstat_inc(sd, lb_balanced[idle]);
+ schedstat_inc(sd->lb_balanced[idle]);
sd->nr_balance_failed = 0;
@@ -7703,11 +7940,12 @@ get_sd_balance_interval(struct sched_domain *sd, int cpu_busy)
}
static inline void
-update_next_balance(struct sched_domain *sd, int cpu_busy, unsigned long *next_balance)
+update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
{
unsigned long interval, next;
- interval = get_sd_balance_interval(sd, cpu_busy);
+ /* used by idle balance, so cpu_busy = 0 */
+ interval = get_sd_balance_interval(sd, 0);
next = sd->last_balance + interval;
if (time_after(*next_balance, next))
@@ -7737,7 +7975,7 @@ static int idle_balance(struct rq *this_rq)
rcu_read_lock();
sd = rcu_dereference_check_sched_domain(this_rq->sd);
if (sd)
- update_next_balance(sd, 0, &next_balance);
+ update_next_balance(sd, &next_balance);
rcu_read_unlock();
goto out;
@@ -7755,7 +7993,7 @@ static int idle_balance(struct rq *this_rq)
continue;
if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) {
- update_next_balance(sd, 0, &next_balance);
+ update_next_balance(sd, &next_balance);
break;
}
@@ -7773,7 +8011,7 @@ static int idle_balance(struct rq *this_rq)
curr_cost += domain_cost;
}
- update_next_balance(sd, 0, &next_balance);
+ update_next_balance(sd, &next_balance);
/*
* Stop searching for tasks to pull if there are
@@ -7863,15 +8101,15 @@ static int active_load_balance_cpu_stop(void *data)
.idle = CPU_IDLE,
};
- schedstat_inc(sd, alb_count);
+ schedstat_inc(sd->alb_count);
p = detach_one_task(&env);
if (p) {
- schedstat_inc(sd, alb_pushed);
+ schedstat_inc(sd->alb_pushed);
/* Active balancing done, reset the failure counter. */
sd->nr_balance_failed = 0;
} else {
- schedstat_inc(sd, alb_failed);
+ schedstat_inc(sd->alb_failed);
}
}
rcu_read_unlock();
@@ -7963,13 +8201,13 @@ static inline void set_cpu_sd_state_busy(void)
int cpu = smp_processor_id();
rcu_read_lock();
- sd = rcu_dereference(per_cpu(sd_busy, cpu));
+ sd = rcu_dereference(per_cpu(sd_llc, cpu));
if (!sd || !sd->nohz_idle)
goto unlock;
sd->nohz_idle = 0;
- atomic_inc(&sd->groups->sgc->nr_busy_cpus);
+ atomic_inc(&sd->shared->nr_busy_cpus);
unlock:
rcu_read_unlock();
}
@@ -7980,13 +8218,13 @@ void set_cpu_sd_state_idle(void)
int cpu = smp_processor_id();
rcu_read_lock();
- sd = rcu_dereference(per_cpu(sd_busy, cpu));
+ sd = rcu_dereference(per_cpu(sd_llc, cpu));
if (!sd || sd->nohz_idle)
goto unlock;
sd->nohz_idle = 1;
- atomic_dec(&sd->groups->sgc->nr_busy_cpus);
+ atomic_dec(&sd->shared->nr_busy_cpus);
unlock:
rcu_read_unlock();
}
@@ -8213,8 +8451,8 @@ end:
static inline bool nohz_kick_needed(struct rq *rq)
{
unsigned long now = jiffies;
+ struct sched_domain_shared *sds;
struct sched_domain *sd;
- struct sched_group_capacity *sgc;
int nr_busy, cpu = rq->cpu;
bool kick = false;
@@ -8242,11 +8480,13 @@ static inline bool nohz_kick_needed(struct rq *rq)
return true;
rcu_read_lock();
- sd = rcu_dereference(per_cpu(sd_busy, cpu));
- if (sd) {
- sgc = sd->groups->sgc;
- nr_busy = atomic_read(&sgc->nr_busy_cpus);
-
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds) {
+ /*
+ * XXX: write a coherent comment on why we do this.
+ * See also: http://lkml.kernel.org/r/20111202010832.602203411@sbsiddha-desk.sc.intel.com
+ */
+ nr_busy = atomic_read(&sds->nr_busy_cpus);
if (nr_busy > 1) {
kick = true;
goto unlock;
@@ -8440,7 +8680,6 @@ static void detach_task_cfs_rq(struct task_struct *p)
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
- int tg_update;
if (!vruntime_normalized(p)) {
/*
@@ -8452,10 +8691,9 @@ static void detach_task_cfs_rq(struct task_struct *p)
}
/* Catch up with the cfs_rq and remove our load when we leave */
- tg_update = update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_cfs_rq_load_avg(now, cfs_rq, false);
detach_entity_load_avg(cfs_rq, se);
- if (tg_update)
- update_tg_load_avg(cfs_rq, false);
+ update_tg_load_avg(cfs_rq, false);
}
static void attach_task_cfs_rq(struct task_struct *p)
@@ -8463,7 +8701,6 @@ static void attach_task_cfs_rq(struct task_struct *p)
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
- int tg_update;
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
@@ -8474,10 +8711,9 @@ static void attach_task_cfs_rq(struct task_struct *p)
#endif
/* Synchronize task with its cfs_rq */
- tg_update = update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_cfs_rq_load_avg(now, cfs_rq, false);
attach_entity_load_avg(cfs_rq, se);
- if (tg_update)
- update_tg_load_avg(cfs_rq, false);
+ update_tg_load_avg(cfs_rq, false);
if (!vruntime_normalized(p))
se->vruntime += cfs_rq->min_vruntime;
diff --git a/kernel/sched/idle_task.c b/kernel/sched/idle_task.c
index 2ce5458bbe1d..5405d3feb112 100644
--- a/kernel/sched/idle_task.c
+++ b/kernel/sched/idle_task.c
@@ -27,8 +27,8 @@ static struct task_struct *
pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
put_prev_task(rq, prev);
-
- schedstat_inc(rq, sched_goidle);
+ update_idle_core(rq);
+ schedstat_inc(rq->sched_goidle);
return rq->idle;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b7fc1ced4380..58df5590d028 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2,6 +2,7 @@
#include <linux/sched.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/rt.h>
+#include <linux/u64_stats_sync.h>
#include <linux/sched/deadline.h>
#include <linux/binfmts.h>
#include <linux/mutex.h>
@@ -15,6 +16,12 @@
#include "cpudeadline.h"
#include "cpuacct.h"
+#ifdef CONFIG_SCHED_DEBUG
+#define SCHED_WARN_ON(x) WARN_ONCE(x, #x)
+#else
+#define SCHED_WARN_ON(x) ((void)(x))
+#endif
+
struct rq;
struct cpuidle_state;
@@ -565,6 +572,8 @@ struct root_domain {
*/
cpumask_var_t rto_mask;
struct cpupri cpupri;
+
+ unsigned long max_cpu_capacity;
};
extern struct root_domain def_root_domain;
@@ -597,7 +606,6 @@ struct rq {
#ifdef CONFIG_SMP
unsigned long last_load_update_tick;
#endif /* CONFIG_SMP */
- u64 nohz_stamp;
unsigned long nohz_flags;
#endif /* CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_NO_HZ_FULL
@@ -723,6 +731,23 @@ static inline int cpu_of(struct rq *rq)
#endif
}
+
+#ifdef CONFIG_SCHED_SMT
+
+extern struct static_key_false sched_smt_present;
+
+extern void __update_idle_core(struct rq *rq);
+
+static inline void update_idle_core(struct rq *rq)
+{
+ if (static_branch_unlikely(&sched_smt_present))
+ __update_idle_core(rq);
+}
+
+#else
+static inline void update_idle_core(struct rq *rq) { }
+#endif
+
DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
@@ -857,8 +882,8 @@ static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
DECLARE_PER_CPU(struct sched_domain *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
+DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
DECLARE_PER_CPU(struct sched_domain *, sd_numa);
-DECLARE_PER_CPU(struct sched_domain *, sd_busy);
DECLARE_PER_CPU(struct sched_domain *, sd_asym);
struct sched_group_capacity {
@@ -870,10 +895,6 @@ struct sched_group_capacity {
unsigned int capacity;
unsigned long next_update;
int imbalance; /* XXX unrelated to capacity but shared group state */
- /*
- * Number of busy cpus in this group.
- */
- atomic_t nr_busy_cpus;
unsigned long cpumask[0]; /* iteration mask */
};
@@ -1260,6 +1281,11 @@ static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
prev->sched_class->put_prev_task(rq, prev);
}
+static inline void set_curr_task(struct rq *rq, struct task_struct *curr)
+{
+ curr->sched_class->set_curr_task(rq);
+}
+
#define sched_class_highest (&stop_sched_class)
#define for_each_class(class) \
for (class = sched_class_highest; class; class = class->next)
@@ -1290,7 +1316,7 @@ static inline void idle_set_state(struct rq *rq,
static inline struct cpuidle_state *idle_get_state(struct rq *rq)
{
- WARN_ON(!rcu_read_lock_held());
+ SCHED_WARN_ON(!rcu_read_lock_held());
return rq->idle_state;
}
#else
@@ -1710,52 +1736,28 @@ static inline void nohz_balance_exit_idle(unsigned int cpu) { }
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+struct irqtime {
+ u64 hardirq_time;
+ u64 softirq_time;
+ u64 irq_start_time;
+ struct u64_stats_sync sync;
+};
-DECLARE_PER_CPU(u64, cpu_hardirq_time);
-DECLARE_PER_CPU(u64, cpu_softirq_time);
-
-#ifndef CONFIG_64BIT
-DECLARE_PER_CPU(seqcount_t, irq_time_seq);
-
-static inline void irq_time_write_begin(void)
-{
- __this_cpu_inc(irq_time_seq.sequence);
- smp_wmb();
-}
-
-static inline void irq_time_write_end(void)
-{
- smp_wmb();
- __this_cpu_inc(irq_time_seq.sequence);
-}
+DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
static inline u64 irq_time_read(int cpu)
{
- u64 irq_time;
- unsigned seq;
+ struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
+ unsigned int seq;
+ u64 total;
do {
- seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
- irq_time = per_cpu(cpu_softirq_time, cpu) +
- per_cpu(cpu_hardirq_time, cpu);
- } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));
-
- return irq_time;
-}
-#else /* CONFIG_64BIT */
-static inline void irq_time_write_begin(void)
-{
-}
+ seq = __u64_stats_fetch_begin(&irqtime->sync);
+ total = irqtime->softirq_time + irqtime->hardirq_time;
+ } while (__u64_stats_fetch_retry(&irqtime->sync, seq));
-static inline void irq_time_write_end(void)
-{
-}
-
-static inline u64 irq_time_read(int cpu)
-{
- return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
+ return total;
}
-#endif /* CONFIG_64BIT */
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
#ifdef CONFIG_CPU_FREQ
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 78955cbea31c..34659a853505 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -29,11 +29,12 @@ rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
if (rq)
rq->rq_sched_info.run_delay += delta;
}
-# define schedstat_enabled() static_branch_unlikely(&sched_schedstats)
-# define schedstat_inc(rq, field) do { if (schedstat_enabled()) { (rq)->field++; } } while (0)
-# define schedstat_add(rq, field, amt) do { if (schedstat_enabled()) { (rq)->field += (amt); } } while (0)
-# define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0)
-# define schedstat_val(rq, field) ((schedstat_enabled()) ? (rq)->field : 0)
+#define schedstat_enabled() static_branch_unlikely(&sched_schedstats)
+#define schedstat_inc(var) do { if (schedstat_enabled()) { var++; } } while (0)
+#define schedstat_add(var, amt) do { if (schedstat_enabled()) { var += (amt); } } while (0)
+#define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0)
+#define schedstat_val(var) (var)
+#define schedstat_val_or_zero(var) ((schedstat_enabled()) ? (var) : 0)
#else /* !CONFIG_SCHEDSTATS */
static inline void
@@ -45,12 +46,13 @@ rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
static inline void
rq_sched_info_depart(struct rq *rq, unsigned long long delta)
{}
-# define schedstat_enabled() 0
-# define schedstat_inc(rq, field) do { } while (0)
-# define schedstat_add(rq, field, amt) do { } while (0)
-# define schedstat_set(var, val) do { } while (0)
-# define schedstat_val(rq, field) 0
-#endif
+#define schedstat_enabled() 0
+#define schedstat_inc(var) do { } while (0)
+#define schedstat_add(var, amt) do { } while (0)
+#define schedstat_set(var, val) do { } while (0)
+#define schedstat_val(var) 0
+#define schedstat_val_or_zero(var) 0
+#endif /* CONFIG_SCHEDSTATS */
#ifdef CONFIG_SCHED_INFO
static inline void sched_info_reset_dequeued(struct task_struct *t)
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index f15d6b6a538a..4f7053579fe3 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -196,27 +196,48 @@ prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
}
EXPORT_SYMBOL(prepare_to_wait_exclusive);
-long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state)
+void init_wait_entry(wait_queue_t *wait, int flags)
{
- unsigned long flags;
-
- if (signal_pending_state(state, current))
- return -ERESTARTSYS;
-
+ wait->flags = flags;
wait->private = current;
wait->func = autoremove_wake_function;
+ INIT_LIST_HEAD(&wait->task_list);
+}
+EXPORT_SYMBOL(init_wait_entry);
+
+long prepare_to_wait_event(wait_queue_head_t *q, wait_queue_t *wait, int state)
+{
+ unsigned long flags;
+ long ret = 0;
spin_lock_irqsave(&q->lock, flags);
- if (list_empty(&wait->task_list)) {
- if (wait->flags & WQ_FLAG_EXCLUSIVE)
- __add_wait_queue_tail(q, wait);
- else
- __add_wait_queue(q, wait);
+ if (unlikely(signal_pending_state(state, current))) {
+ /*
+ * Exclusive waiter must not fail if it was selected by wakeup,
+ * it should "consume" the condition we were waiting for.
+ *
+ * The caller will recheck the condition and return success if
+ * we were already woken up, we can not miss the event because
+ * wakeup locks/unlocks the same q->lock.
+ *
+ * But we need to ensure that set-condition + wakeup after that
+ * can't see us, it should wake up another exclusive waiter if
+ * we fail.
+ */
+ list_del_init(&wait->task_list);
+ ret = -ERESTARTSYS;
+ } else {
+ if (list_empty(&wait->task_list)) {
+ if (wait->flags & WQ_FLAG_EXCLUSIVE)
+ __add_wait_queue_tail(q, wait);
+ else
+ __add_wait_queue(q, wait);
+ }
+ set_current_state(state);
}
- set_current_state(state);
spin_unlock_irqrestore(&q->lock, flags);
- return 0;
+ return ret;
}
EXPORT_SYMBOL(prepare_to_wait_event);
@@ -255,39 +276,6 @@ void finish_wait(wait_queue_head_t *q, wait_queue_t *wait)
}
EXPORT_SYMBOL(finish_wait);
-/**
- * abort_exclusive_wait - abort exclusive waiting in a queue
- * @q: waitqueue waited on
- * @wait: wait descriptor
- * @mode: runstate of the waiter to be woken
- * @key: key to identify a wait bit queue or %NULL
- *
- * Sets current thread back to running state and removes
- * the wait descriptor from the given waitqueue if still
- * queued.
- *
- * Wakes up the next waiter if the caller is concurrently
- * woken up through the queue.
- *
- * This prevents waiter starvation where an exclusive waiter
- * aborts and is woken up concurrently and no one wakes up
- * the next waiter.
- */
-void abort_exclusive_wait(wait_queue_head_t *q, wait_queue_t *wait,
- unsigned int mode, void *key)
-{
- unsigned long flags;
-
- __set_current_state(TASK_RUNNING);
- spin_lock_irqsave(&q->lock, flags);
- if (!list_empty(&wait->task_list))
- list_del_init(&wait->task_list);
- else if (waitqueue_active(q))
- __wake_up_locked_key(q, mode, key);
- spin_unlock_irqrestore(&q->lock, flags);
-}
-EXPORT_SYMBOL(abort_exclusive_wait);
-
int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key)
{
int ret = default_wake_function(wait, mode, sync, key);
@@ -425,20 +413,29 @@ int __sched
__wait_on_bit_lock(wait_queue_head_t *wq, struct wait_bit_queue *q,
wait_bit_action_f *action, unsigned mode)
{
- do {
- int ret;
+ int ret = 0;
+ for (;;) {
prepare_to_wait_exclusive(wq, &q->wait, mode);
- if (!test_bit(q->key.bit_nr, q->key.flags))
- continue;
- ret = action(&q->key, mode);
- if (!ret)
- continue;
- abort_exclusive_wait(wq, &q->wait, mode, &q->key);
- return ret;
- } while (test_and_set_bit(q->key.bit_nr, q->key.flags));
- finish_wait(wq, &q->wait);
- return 0;
+ if (test_bit(q->key.bit_nr, q->key.flags)) {
+ ret = action(&q->key, mode);
+ /*
+ * See the comment in prepare_to_wait_event().
+ * finish_wait() does not necessarily takes wq->lock,
+ * but test_and_set_bit() implies mb() which pairs with
+ * smp_mb__after_atomic() before wake_up_page().
+ */
+ if (ret)
+ finish_wait(wq, &q->wait);
+ }
+ if (!test_and_set_bit(q->key.bit_nr, q->key.flags)) {
+ if (!ret)
+ finish_wait(wq, &q->wait);
+ return 0;
+ } else if (ret) {
+ return ret;
+ }
+ }
}
EXPORT_SYMBOL(__wait_on_bit_lock);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-11 20:06:31 +0000