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Commit f339b9dc authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Fix schedstat.nr_wakeups_migrate 



While looking over the code I found that with the ttwu rework the
nr_wakeups_migrate test broke since we now switch cpus prior to
calling ttwu_stat(), hence the test is always true.

Cure this by passing the migration state in wake_flags. Also move the
whole test under CONFIG_SMP, its hard to migrate tasks on UP :-)

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-pwwxl7gdqs5676f1d4cx6pj7@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f01114cb

include/linux/sched.h

+1 −0
Original line number Diff line number Diff line
@@ -1063,6 +1063,7 @@ struct sched_domain; 
 */

#define WF_SYNC		0x01		/* waker goes to sleep after wakup */

#define WF_FORK		0x02		/* child wakeup after fork */

#define WF_MIGRATED	0x04		/* internal use, task got migrated */



#define ENQUEUE_WAKEUP		1

#define ENQUEUE_HEAD		2

kernel/sched.c

+7 −4
Original line number Diff line number Diff line
@@ -2447,6 +2447,10 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 
		}

		rcu_read_unlock();

	}



	if (wake_flags & WF_MIGRATED)

		schedstat_inc(p, se.statistics.nr_wakeups_migrate);



#endif /* CONFIG_SMP */



	schedstat_inc(rq, ttwu_count);
@@ -2455,9 +2459,6 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags) 
	if (wake_flags & WF_SYNC)

		schedstat_inc(p, se.statistics.nr_wakeups_sync);



	if (cpu != task_cpu(p))

		schedstat_inc(p, se.statistics.nr_wakeups_migrate);



#endif /* CONFIG_SCHEDSTATS */

}
@@ -2675,8 +2676,10 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) 
		p->sched_class->task_waking(p);



	cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);

	if (task_cpu(p) != cpu)

	if (task_cpu(p) != cpu) {

		wake_flags |= WF_MIGRATED;

		set_task_cpu(p, cpu);

	}

#endif /* CONFIG_SMP */



	ttwu_queue(p, cpu);