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authorIngo Molnar <mingo@elte.hu>2010-06-08 23:20:59 +0200
committerIngo Molnar <mingo@elte.hu>2010-06-08 23:20:59 +0200
commit95ae3c59fa8ad616c73745e21154b5af0fb10168 (patch)
treec08f1bcad8f619c5097208cbfa85170411033095 /kernel/sched.c
parentdc61b1d65e353d638b2445f71fb8e5b5630f2415 (diff)
parent21aa9af03d06cb1d19a3738e5cf12acff984e69b (diff)
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Merge branch 'sched-wq' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into sched/core
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c205
1 files changed, 151 insertions, 54 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 2aaceebd484..8f351c56567 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -77,6 +77,7 @@
#include <asm/irq_regs.h>
#include "sched_cpupri.h"
+#include "workqueue_sched.h"
#define CREATE_TRACE_POINTS
#include <trace/events/sched.h>
@@ -2264,11 +2265,55 @@ static void update_avg(u64 *avg, u64 sample)
}
#endif
-/***
+static inline void ttwu_activate(struct task_struct *p, struct rq *rq,
+ bool is_sync, bool is_migrate, bool is_local,
+ unsigned long en_flags)
+{
+ schedstat_inc(p, se.statistics.nr_wakeups);
+ if (is_sync)
+ schedstat_inc(p, se.statistics.nr_wakeups_sync);
+ if (is_migrate)
+ schedstat_inc(p, se.statistics.nr_wakeups_migrate);
+ if (is_local)
+ schedstat_inc(p, se.statistics.nr_wakeups_local);
+ else
+ schedstat_inc(p, se.statistics.nr_wakeups_remote);
+
+ activate_task(rq, p, en_flags);
+}
+
+static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
+ int wake_flags, bool success)
+{
+ trace_sched_wakeup(p, success);
+ check_preempt_curr(rq, p, wake_flags);
+
+ p->state = TASK_RUNNING;
+#ifdef CONFIG_SMP
+ if (p->sched_class->task_woken)
+ p->sched_class->task_woken(rq, p);
+
+ if (unlikely(rq->idle_stamp)) {
+ u64 delta = rq->clock - rq->idle_stamp;
+ u64 max = 2*sysctl_sched_migration_cost;
+
+ if (delta > max)
+ rq->avg_idle = max;
+ else
+ update_avg(&rq->avg_idle, delta);
+ rq->idle_stamp = 0;
+ }
+#endif
+ /* if a worker is waking up, notify workqueue */
+ if ((p->flags & PF_WQ_WORKER) && success)
+ wq_worker_waking_up(p, cpu_of(rq));
+}
+
+/**
* try_to_wake_up - wake up a thread
- * @p: the to-be-woken-up thread
+ * @p: the thread to be awakened
* @state: the mask of task states that can be woken
- * @sync: do a synchronous wakeup?
+ * @wake_flags: wake modifier flags (WF_*)
*
* Put it on the run-queue if it's not already there. The "current"
* thread is always on the run-queue (except when the actual
@@ -2276,7 +2321,8 @@ static void update_avg(u64 *avg, u64 sample)
* the simpler "current->state = TASK_RUNNING" to mark yourself
* runnable without the overhead of this.
*
- * returns failure only if the task is already active.
+ * Returns %true if @p was woken up, %false if it was already running
+ * or @state didn't match @p's state.
*/
static int try_to_wake_up(struct task_struct *p, unsigned int state,
int wake_flags)
@@ -2356,38 +2402,11 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
out_activate:
#endif /* CONFIG_SMP */
- schedstat_inc(p, se.statistics.nr_wakeups);
- if (wake_flags & WF_SYNC)
- schedstat_inc(p, se.statistics.nr_wakeups_sync);
- if (orig_cpu != cpu)
- schedstat_inc(p, se.statistics.nr_wakeups_migrate);
- if (cpu == this_cpu)
- schedstat_inc(p, se.statistics.nr_wakeups_local);
- else
- schedstat_inc(p, se.statistics.nr_wakeups_remote);
- activate_task(rq, p, en_flags);
+ ttwu_activate(p, rq, wake_flags & WF_SYNC, orig_cpu != cpu,
+ cpu == this_cpu, en_flags);
success = 1;
-
out_running:
- trace_sched_wakeup(p, success);
- check_preempt_curr(rq, p, wake_flags);
-
- p->state = TASK_RUNNING;
-#ifdef CONFIG_SMP
- if (p->sched_class->task_woken)
- p->sched_class->task_woken(rq, p);
-
- if (unlikely(rq->idle_stamp)) {
- u64 delta = rq->clock - rq->idle_stamp;
- u64 max = 2*sysctl_sched_migration_cost;
-
- if (delta > max)
- rq->avg_idle = max;
- else
- update_avg(&rq->avg_idle, delta);
- rq->idle_stamp = 0;
- }
-#endif
+ ttwu_post_activation(p, rq, wake_flags, success);
out:
task_rq_unlock(rq, &flags);
put_cpu();
@@ -2396,6 +2415,37 @@ out:
}
/**
+ * try_to_wake_up_local - try to wake up a local task with rq lock held
+ * @p: the thread to be awakened
+ *
+ * Put @p on the run-queue if it's not alredy there. The caller must
+ * ensure that this_rq() is locked, @p is bound to this_rq() and not
+ * the current task. this_rq() stays locked over invocation.
+ */
+static void try_to_wake_up_local(struct task_struct *p)
+{
+ struct rq *rq = task_rq(p);
+ bool success = false;
+
+ BUG_ON(rq != this_rq());
+ BUG_ON(p == current);
+ lockdep_assert_held(&rq->lock);
+
+ if (!(p->state & TASK_NORMAL))
+ return;
+
+ if (!p->se.on_rq) {
+ if (likely(!task_running(rq, p))) {
+ schedstat_inc(rq, ttwu_count);
+ schedstat_inc(rq, ttwu_local);
+ }
+ ttwu_activate(p, rq, false, false, true, ENQUEUE_WAKEUP);
+ success = true;
+ }
+ ttwu_post_activation(p, rq, 0, success);
+}
+
+/**
* wake_up_process - Wake up a specific process
* @p: The process to be woken up.
*
@@ -3600,10 +3650,24 @@ need_resched_nonpreemptible:
clear_tsk_need_resched(prev);
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
- if (unlikely(signal_pending_state(prev->state, prev)))
+ if (unlikely(signal_pending_state(prev->state, prev))) {
prev->state = TASK_RUNNING;
- else
+ } else {
+ /*
+ * If a worker is going to sleep, notify and
+ * ask workqueue whether it wants to wake up a
+ * task to maintain concurrency. If so, wake
+ * up the task.
+ */
+ if (prev->flags & PF_WQ_WORKER) {
+ struct task_struct *to_wakeup;
+
+ to_wakeup = wq_worker_sleeping(prev, cpu);
+ if (to_wakeup)
+ try_to_wake_up_local(to_wakeup);
+ }
deactivate_task(rq, prev, DEQUEUE_SLEEP);
+ }
switch_count = &prev->nvcsw;
}
@@ -5804,20 +5868,49 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
*/
static struct notifier_block __cpuinitdata migration_notifier = {
.notifier_call = migration_call,
- .priority = 10
+ .priority = CPU_PRI_MIGRATION,
};
+static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ case CPU_DOWN_FAILED:
+ set_cpu_active((long)hcpu, true);
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
+static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DOWN_PREPARE:
+ set_cpu_active((long)hcpu, false);
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
static int __init migration_init(void)
{
void *cpu = (void *)(long)smp_processor_id();
int err;
- /* Start one for the boot CPU: */
+ /* Initialize migration for the boot CPU */
err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
BUG_ON(err == NOTIFY_BAD);
migration_call(&migration_notifier, CPU_ONLINE, cpu);
register_cpu_notifier(&migration_notifier);
+ /* Register cpu active notifiers */
+ cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
+ cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);
+
return 0;
}
early_initcall(migration_init);
@@ -7276,29 +7369,35 @@ int __init sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
}
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
-#ifndef CONFIG_CPUSETS
/*
- * Add online and remove offline CPUs from the scheduler domains.
- * When cpusets are enabled they take over this function.
+ * Update cpusets according to cpu_active mask. If cpusets are
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
+ * around partition_sched_domains().
*/
-static int update_sched_domains(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+static int __cpuexit cpuset_cpu_active(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
{
- switch (action) {
+ switch (action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- partition_sched_domains(1, NULL, NULL);
+ cpuset_update_active_cpus();
return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+}
+static int __cpuexit cpuset_cpu_inactive(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_DOWN_PREPARE:
+ cpuset_update_active_cpus();
+ return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}
-#endif
static int update_runtime(struct notifier_block *nfb,
unsigned long action, void *hcpu)
@@ -7344,10 +7443,8 @@ void __init sched_init_smp(void)
mutex_unlock(&sched_domains_mutex);
put_online_cpus();
-#ifndef CONFIG_CPUSETS
- /* XXX: Theoretical race here - CPU may be hotplugged now */
- hotcpu_notifier(update_sched_domains, 0);
-#endif
+ hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
+ hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
/* RT runtime code needs to handle some hotplug events */
hotcpu_notifier(update_runtime, 0);