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Commit 2002c695 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: release buddies on yield 



Clear buddies on yield, so that the buddy rules don't schedule them
despite them being placed right-most.

This fixed a performance regression with yield-happy binary JVMs.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Tested-by: default avatarLin Ming <ming.m.lin@intel.com>
parent ad474cac

kernel/sched_fair.c

+12 −5
Original line number Diff line number Diff line
@@ -716,6 +716,15 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) 
		__enqueue_entity(cfs_rq, se);

}



static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)

{

	if (cfs_rq->last == se)

		cfs_rq->last = NULL;



	if (cfs_rq->next == se)

		cfs_rq->next = NULL;

}



static void

dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)

{
@@ -738,11 +747,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) 
#endif

	}



	if (cfs_rq->last == se)

		cfs_rq->last = NULL;



	if (cfs_rq->next == se)

		cfs_rq->next = NULL;

	clear_buddies(cfs_rq, se);



	if (se != cfs_rq->curr)

		__dequeue_entity(cfs_rq, se);
@@ -977,6 +982,8 @@ static void yield_task_fair(struct rq *rq) 
	if (unlikely(cfs_rq->nr_running == 1))

		return;



	clear_buddies(cfs_rq, se);



	if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {

		update_rq_clock(rq);

		/*