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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: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Lin Ming <ming.m.lin@intel.com>
This commit is contained in:
Peter Zijlstra 2008-11-11 11:52:33 +01:00 committed by Ingo Molnar
parent ad474caca3
commit 2002c69595
1 changed files with 12 additions and 5 deletions
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17
kernel/sched_fair.c
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@ -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);
/*