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sched: fix: move the CPU check into ->task_new_fair()

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noticed by Peter Zijlstra:

fix: move the CPU check into ->task_new_fair(), this way we
can call place_entity() and get child ->vruntime right at
initial wakeup time.

(without this there can be large latencies)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
This commit is contained in:
Ingo Molnar 2007-10-15 17:00:14 +02:00
parent 0702e3ebc1
commit 00bf7bfc2e
2 changed files with 3 additions and 5 deletions
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5
kernel/sched.c
View File

@ -1660,17 +1660,14 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
{
unsigned long flags;
struct rq *rq;
int this_cpu;
rq = task_rq_lock(p, &flags);
BUG_ON(p->state != TASK_RUNNING);
this_cpu = smp_processor_id(); /* parent's CPU */
update_rq_clock(rq);
p->prio = effective_prio(p);
if (task_cpu(p) != this_cpu || !p->sched_class->task_new ||
!current->se.on_rq) {
if (!p->sched_class->task_new || !current->se.on_rq || !rq->cfs.curr) {
activate_task(rq, p, 0);
} else {
/*

3
kernel/sched_fair.c
View File

@ -1007,13 +1007,14 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
{
struct cfs_rq *cfs_rq = task_cfs_rq(p);
struct sched_entity *se = &p->se, *curr = cfs_rq->curr;
int this_cpu = smp_processor_id();
sched_info_queued(p);
update_curr(cfs_rq);
place_entity(cfs_rq, se, 1);
if (sysctl_sched_child_runs_first &&
if (sysctl_sched_child_runs_first && this_cpu == task_cpu(p) &&
curr->vruntime < se->vruntime) {
/*
* Upon rescheduling, sched_class::put_prev_task() will place