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Merge branch 'tip/sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into sched/core

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Pull a scheduler optimization commit from Steven Rostedt.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2012-04-14 15:12:00 +02:00
commit 4cbb62148c
1 changed files with 26 additions and 30 deletions
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56
kernel/sched/rt.c
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@ -1803,44 +1803,40 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p)
static void set_cpus_allowed_rt(struct task_struct *p,
const struct cpumask *new_mask)
{
int weight = cpumask_weight(new_mask);
struct rq *rq;
int weight;
BUG_ON(!rt_task(p));
if (!p->on_rq)
return;
weight = cpumask_weight(new_mask);
/*
* Update the migration status of the RQ if we have an RT task
* which is running AND changing its weight value.
* Only update if the process changes its state from whether it
* can migrate or not.
*/
if (p->on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
if ((p->rt.nr_cpus_allowed > 1) == (weight > 1))
return;
if (!task_current(rq, p)) {
/*
* Make sure we dequeue this task from the pushable list
* before going further. It will either remain off of
* the list because we are no longer pushable, or it
* will be requeued.
*/
if (p->rt.nr_cpus_allowed > 1)
dequeue_pushable_task(rq, p);
rq = task_rq(p);
/*
* Requeue if our weight is changing and still > 1
*/
if (weight > 1)
enqueue_pushable_task(rq, p);
}
if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
} else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
BUG_ON(!rq->rt.rt_nr_migratory);
rq->rt.rt_nr_migratory--;
}
update_rt_migration(&rq->rt);
/*
* The process used to be able to migrate OR it can now migrate
*/
if (weight <= 1) {
if (!task_current(rq, p))
dequeue_pushable_task(rq, p);
BUG_ON(!rq->rt.rt_nr_migratory);
rq->rt.rt_nr_migratory--;
} else {
if (!task_current(rq, p))
enqueue_pushable_task(rq, p);
rq->rt.rt_nr_migratory++;
}
update_rt_migration(&rq->rt);
}
/* Assumes rq->lock is held */