unsigned long flags;
int cpu, success = 0;
+ if (p == current) {
+ /*
+ * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
+ * == smp_processor_id()'. Together this means we can special
+ * case the whole 'p->on_rq && ttwu_remote()' case below
+ * without taking any locks.
+ *
+ * In particular:
+ * - we rely on Program-Order guarantees for all the ordering,
+ * - we're serialized against set_special_state() by virtue of
+ * it disabling IRQs (this allows not taking ->pi_lock).
+ */
+ if (!(p->state & state))
+ return false;
+
+ success = 1;
+ cpu = task_cpu(p);
+ trace_sched_waking(p);
+ p->state = TASK_RUNNING;
+ trace_sched_wakeup(p);
+ goto out;
+ }
+
/*
* If we are going to wake up a thread waiting for CONDITION we
* need to ensure that CONDITION=1 done by the caller can not be
raw_spin_lock_irqsave(&p->pi_lock, flags);
smp_mb__after_spinlock();
if (!(p->state & state))
- goto out;
+ goto unlock;
trace_sched_waking(p);
*/
smp_rmb();
if (p->on_rq && ttwu_remote(p, wake_flags))
- goto stat;
+ goto unlock;
#ifdef CONFIG_SMP
/*
#endif /* CONFIG_SMP */
ttwu_queue(p, cpu, wake_flags);
-stat:
- ttwu_stat(p, cpu, wake_flags);
-out:
+unlock:
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+out:
+ if (success)
+ ttwu_stat(p, cpu, wake_flags);
return success;
}