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sched: Change the sched_class::set_cpus_allowed() calling context

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Change the calling context of sched_class::set_cpus_allowed() such
that we can assume the task is inactive.

This allows us to easily make changes that affect accounting done by
enqueue/dequeue. This does in fact completely remove
set_cpus_allowed_rt() and greatly reduces set_cpus_allowed_dl().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dedekind1@gmail.com
Cc: juri.lelli@arm.com
Cc: mgorman@suse.de
Cc: riel@redhat.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20150515154833.667516139@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2015-05-15 17:43:36 +02:00 committed by Ingo Molnar
parent c5b2803840
commit 6c37067e27
3 changed files with 26 additions and 81 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

23
kernel/sched/core.c
View file

@ -1163,8 +1163,31 @@ void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_ma
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
struct rq *rq = task_rq(p);
bool queued, running;
lockdep_assert_held(&p->pi_lock);
queued = task_on_rq_queued(p);
running = task_current(rq, p);
if (queued) {
/*
* Because __kthread_bind() calls this on blocked tasks without
* holding rq->lock.
*/
lockdep_assert_held(&rq->lock);
dequeue_task(rq, p, 0);
}
if (running)
put_prev_task(rq, p);
p->sched_class->set_cpus_allowed(p, new_mask);
if (running)
p->sched_class->set_curr_task(rq);
if (queued)
enqueue_task(rq, p, 0);
}
/*

39
kernel/sched/deadline.c
View file

@ -1668,9 +1668,8 @@ static void task_woken_dl(struct rq *rq, struct task_struct *p)
static void set_cpus_allowed_dl(struct task_struct *p,
const struct cpumask *new_mask)
{
struct rq *rq;
struct root_domain *src_rd;
int weight;
struct rq *rq;
BUG_ON(!dl_task(p));
@ -1696,41 +1695,7 @@ static void set_cpus_allowed_dl(struct task_struct *p,
raw_spin_unlock(&src_dl_b->lock);
}
weight = cpumask_weight(new_mask);
/*
* Only update if the process changes its state from whether it
* can migrate or not.
*/
if ((p->nr_cpus_allowed > 1) == (weight > 1))
goto done;
/*
* Update only if the task is actually running (i.e.,
* it is on the rq AND it is not throttled).
*/
if (!on_dl_rq(&p->dl))
goto done;
/*
* The process used to be able to migrate OR it can now migrate
*/
if (weight <= 1) {
if (!task_current(rq, p))
dequeue_pushable_dl_task(rq, p);
BUG_ON(!rq->dl.dl_nr_migratory);
rq->dl.dl_nr_migratory--;
} else {
if (!task_current(rq, p))
enqueue_pushable_dl_task(rq, p);
rq->dl.dl_nr_migratory++;
}
update_dl_migration(&rq->dl);
done:
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = weight;
set_cpus_allowed_common(p, new_mask);
}
/* Assumes rq->lock is held */

45
kernel/sched/rt.c
View file

@ -2076,49 +2076,6 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p)
push_rt_tasks(rq);
}
static void set_cpus_allowed_rt(struct task_struct *p,
const struct cpumask *new_mask)
{
struct rq *rq;
int weight;
BUG_ON(!rt_task(p));
weight = cpumask_weight(new_mask);
/*
* Only update if the process changes its state from whether it
* can migrate or not.
*/
if ((p->nr_cpus_allowed > 1) == (weight > 1))
goto done;
if (!task_on_rq_queued(p))
goto done;
rq = task_rq(p);
/*
* 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);
done:
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = weight;
}
/* Assumes rq->lock is held */
static void rq_online_rt(struct rq *rq)
{
@ -2327,7 +2284,7 @@ const struct sched_class rt_sched_class = {
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_rt,
.set_cpus_allowed = set_cpus_allowed_rt,
.set_cpus_allowed = set_cpus_allowed_common,
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
.task_woken = task_woken_rt,