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authorIngo Molnar <mingo@kernel.org>2012-04-14 15:12:00 +0200
committerIngo Molnar <mingo@kernel.org>2012-04-14 15:12:04 +0200
commit4cbb62148cd686c2d3618861deb15eeb83744405 (patch)
treeae20584f1375ee80a419d0cc60a7cde8c5cf9cea /kernel/sched/rt.c
parent668ce0ac707719d866af7e432e518af7b4c575ad (diff)
parent8d3d5ada56a692d36a9d55858881147ec10cfeb6 (diff)
downloadop-kernel-dev-4cbb62148cd686c2d3618861deb15eeb83744405.zip
op-kernel-dev-4cbb62148cd686c2d3618861deb15eeb83744405.tar.gz
Merge branch 'tip/sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into sched/core
Pull a scheduler optimization commit from Steven Rostedt. Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/rt.c')
-rw-r--r--kernel/sched/rt.c56
1 files changed, 26 insertions, 30 deletions
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 44af55e..c5565c3 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -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));
- /*
- * Update the migration status of the RQ if we have an RT task
- * which is running AND changing its weight value.
- */
- if (p->on_rq && (weight != p->rt.nr_cpus_allowed)) {
- struct rq *rq = task_rq(p);
-
- 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);
+ if (!p->on_rq)
+ return;
- /*
- * Requeue if our weight is changing and still > 1
- */
- if (weight > 1)
- enqueue_pushable_task(rq, p);
+ weight = cpumask_weight(new_mask);
- }
+ /*
+ * Only update if the process changes its state from whether it
+ * can migrate or not.
+ */
+ if ((p->rt.nr_cpus_allowed > 1) == (weight > 1))
+ return;
- 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--;
- }
+ rq = task_rq(p);
- 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 */
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