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Commit 54fdc581 authored by Fabio Checconi's avatar Fabio Checconi Committed by Ingo Molnar
Browse files

sched: Account for vruntime wrapping 



I spotted two sites that didn't take vruntime wrap-around into
account. Fix these by creating a comparison helper that does do
so.

Signed-off-by: default avatarFabio Checconi <fabio@gandalf.sssup.it>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 78af08d9

kernel/sched_fair.c

+8 −2
Original line number Diff line number Diff line
@@ -266,6 +266,12 @@ static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) 
	return min_vruntime;

}



static inline int entity_before(struct sched_entity *a,

				struct sched_entity *b)

{

	return (s64)(a->vruntime - b->vruntime) < 0;

}



static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)

{

	return se->vruntime - cfs_rq->min_vruntime;
@@ -1017,7 +1023,7 @@ static void yield_task_fair(struct rq *rq) 
	/*

	 * Already in the rightmost position?

	 */

	if (unlikely(!rightmost || rightmost->vruntime < se->vruntime))

	if (unlikely(!rightmost || entity_before(rightmost, se)))

		return;



	/*
@@ -1713,7 +1719,7 @@ static void task_new_fair(struct rq *rq, struct task_struct *p) 


	/* 'curr' will be NULL if the child belongs to a different group */

	if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) &&

			curr && curr->vruntime < se->vruntime) {

			curr && entity_before(curr, se)) {

		/*

		 * Upon rescheduling, sched_class::put_prev_task() will place

		 * 'current' within the tree based on its new key value.