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Commit 8651a86c authored by Srivatsa Vaddagiri's avatar Srivatsa Vaddagiri Committed by Ingo Molnar
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sched: group scheduler wakeup latency fix



group scheduler wakeup latency fix: when checking for preemption
we must check cross-group too, not just intra-group.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 57cb499d
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+16 −5
Original line number Original line Diff line number Diff line
@@ -796,7 +796,8 @@ static void yield_task_fair(struct rq *rq)
static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
{
{
	struct task_struct *curr = rq->curr;
	struct task_struct *curr = rq->curr;
	struct cfs_rq *cfs_rq = task_cfs_rq(curr);
	struct cfs_rq *cfs_rq = task_cfs_rq(curr), *pcfs_rq;
	struct sched_entity *se = &curr->se, *pse = &p->se;


	if (unlikely(rt_prio(p->prio))) {
	if (unlikely(rt_prio(p->prio))) {
		update_rq_clock(rq);
		update_rq_clock(rq);
@@ -804,11 +805,21 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p)
		resched_task(curr);
		resched_task(curr);
		return;
		return;
	}
	}
	if (is_same_group(curr, p)) {

		s64 delta = curr->se.vruntime - p->se.vruntime;
	for_each_sched_entity(se) {
		cfs_rq = cfs_rq_of(se);
		pcfs_rq = cfs_rq_of(pse);

		if (cfs_rq == pcfs_rq) {
			s64 delta = se->vruntime - pse->vruntime;


			if (delta > (s64)sysctl_sched_wakeup_granularity)
			if (delta > (s64)sysctl_sched_wakeup_granularity)
				resched_task(curr);
				resched_task(curr);
			break;
		}
#ifdef CONFIG_FAIR_GROUP_SCHED
		pse = pse->parent;
#endif
	}
	}
}
}