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sched: clean up new task placement

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clean up new task placement.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
This commit is contained in:
Peter Zijlstra 2007-10-15 17:00:05 +02:00 committed by Ingo Molnar
parent 2e09bf556f
commit aeb73b0403
1 changed files with 42 additions and 15 deletions
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57
kernel/sched_fair.c
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@ -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:
*/
@ -529,6 +544,31 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
#endif
}
static void
place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
{
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 (!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)
{
@ -538,19 +578,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
update_curr(cfs_rq);
if (wakeup) {
u64 min_runtime, latency;
min_runtime = cfs_rq->min_vruntime;
min_runtime += sysctl_sched_latency/2;
if (sched_feat(NEW_FAIR_SLEEPERS)) {
latency = calc_weighted(sysctl_sched_latency, se);
if (min_runtime > latency)
min_runtime -= latency;
}
se->vruntime = max(se->vruntime, min_runtime);
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,