Commit aeb73b04 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: clean up new task placement 



clean up new task placement.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
parent 2e09bf55

kernel/sched_fair.c

+42 −15
Original line number Diff line number Diff line
@@ -199,6 +199,21 @@ static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) 
	return rb_entry(first_fair(cfs_rq), struct sched_entity, run_node);

}



static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)

{

	struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;

	struct sched_entity *se = NULL;

	struct rb_node *parent;



	while (*link) {

		parent = *link;

		se = rb_entry(parent, struct sched_entity, run_node);

		link = &parent->rb_right;

	}



	return se;

}



/**************************************************************

 * Scheduling class statistics methods:

 */
@@ -530,27 +545,40 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) 
}



static void

enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)

place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)

{

	/*

	 * Update the fair clock.

	 */

	update_curr(cfs_rq);



	if (wakeup) {

	struct sched_entity *last = __pick_last_entity(cfs_rq);

	u64 min_runtime, latency;



	min_runtime = cfs_rq->min_vruntime;

	if (last) {

		min_runtime += last->vruntime;

		min_runtime >>= 1;

		if (initial && sched_feat(START_DEBIT))

			min_runtime += sysctl_sched_latency/2;

	}



		if (sched_feat(NEW_FAIR_SLEEPERS)) {

			latency = calc_weighted(sysctl_sched_latency, se);

	if (!initial && sched_feat(NEW_FAIR_SLEEPERS)) {

		latency = sysctl_sched_latency;

		if (min_runtime > latency)

			min_runtime -= latency;

		else

			min_runtime = 0;

	}



	se->vruntime = max(se->vruntime, min_runtime);

}



static void

enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)

{

	/*

	 * Update the fair clock.

	 */

	update_curr(cfs_rq);



	if (wakeup) {

		place_entity(cfs_rq, se, 0);

		enqueue_sleeper(cfs_rq, se);

	}
@@ -1033,8 +1061,7 @@ static void task_new_fair(struct rq *rq, struct task_struct *p) 
	sched_info_queued(p);



	update_curr(cfs_rq);

	se->vruntime = cfs_rq->min_vruntime;

	update_stats_enqueue(cfs_rq, se);

	place_entity(cfs_rq, se, 1);



	/*

	 * The first wait is dominated by the child-runs-first logic,