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Commit 02479099 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: fix buddies for group scheduling 



Impact: scheduling order fix for group scheduling

For each level in the hierarchy, set the buddy to point to the right entity.
Therefore, when we do the hierarchical schedule, we have a fair chance of
ending up where we meant to.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarMike Galbraith <efault@gmx.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4793241b

kernel/sched_fair.c

+14 −2
Original line number Diff line number Diff line
@@ -1319,6 +1319,18 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) 
	return 0;

}



static void set_last_buddy(struct sched_entity *se)

{

	for_each_sched_entity(se)

		cfs_rq_of(se)->last = se;

}



static void set_next_buddy(struct sched_entity *se)

{

	for_each_sched_entity(se)

		cfs_rq_of(se)->next = se;

}



/*

 * Preempt the current task with a newly woken task if needed:

 */
@@ -1352,8 +1364,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync) 
	 * obvious reasons its a bad idea to schedule back to the idle thread.

	 */

	if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))

		cfs_rq_of(se)->last = se;

	cfs_rq_of(pse)->next = pse;

		set_last_buddy(se);

	set_next_buddy(pse);



	/*

	 * We can come here with TIF_NEED_RESCHED already set from new task