Commit c5b28038 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

sched: Make sched_class::set_cpus_allowed() unconditional

Give every class a set_cpus_allowed() method, this enables some small
optimization in the RT,DL implementation by avoiding a double
cpumask_weight() call.
Signed-off-by: default avatarPeter 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/20150515154833.614517487@infradead.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 25834c73
......@@ -1151,15 +1151,20 @@ static int migration_cpu_stop(void *data)
return 0;
}
/*
* sched_class::set_cpus_allowed must do the below, but is not required to
* actually call this function.
*/
void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
{
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = cpumask_weight(new_mask);
}
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
lockdep_assert_held(&p->pi_lock);
if (p->sched_class->set_cpus_allowed)
p->sched_class->set_cpus_allowed(p, new_mask);
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = cpumask_weight(new_mask);
}
/*
......
......@@ -1696,13 +1696,6 @@ static void set_cpus_allowed_dl(struct task_struct *p,
raw_spin_unlock(&src_dl_b->lock);
}
/*
* 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))
return;
weight = cpumask_weight(new_mask);
/*
......@@ -1710,7 +1703,14 @@ static void set_cpus_allowed_dl(struct task_struct *p,
* can migrate or not.
*/
if ((p->nr_cpus_allowed > 1) == (weight > 1))
return;
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
......@@ -1727,6 +1727,10 @@ static void set_cpus_allowed_dl(struct task_struct *p,
}
update_dl_migration(&rq->dl);
done:
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = weight;
}
/* Assumes rq->lock is held */
......
......@@ -8252,6 +8252,7 @@ const struct sched_class fair_sched_class = {
.task_waking = task_waking_fair,
.task_dead = task_dead_fair,
.set_cpus_allowed = set_cpus_allowed_common,
#endif
.set_curr_task = set_curr_task_fair,
......
......@@ -96,6 +96,7 @@ const struct sched_class idle_sched_class = {
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_idle,
.set_cpus_allowed = set_cpus_allowed_common,
#endif
.set_curr_task = set_curr_task_idle,
......
......@@ -2084,9 +2084,6 @@ static void set_cpus_allowed_rt(struct task_struct *p,
BUG_ON(!rt_task(p));
if (!task_on_rq_queued(p))
return;
weight = cpumask_weight(new_mask);
/*
......@@ -2094,7 +2091,10 @@ static void set_cpus_allowed_rt(struct task_struct *p,
* can migrate or not.
*/
if ((p->nr_cpus_allowed > 1) == (weight > 1))
return;
goto done;
if (!task_on_rq_queued(p))
goto done;
rq = task_rq(p);
......@@ -2113,6 +2113,10 @@ static void set_cpus_allowed_rt(struct task_struct *p,
}
update_rt_migration(&rq->rt);
done:
cpumask_copy(&p->cpus_allowed, new_mask);
p->nr_cpus_allowed = weight;
}
/* Assumes rq->lock is held */
......
......@@ -1255,6 +1255,8 @@ extern void trigger_load_balance(struct rq *rq);
extern void idle_enter_fair(struct rq *this_rq);
extern void idle_exit_fair(struct rq *this_rq);
extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask);
#else
static inline void idle_enter_fair(struct rq *rq) { }
......
......@@ -123,6 +123,7 @@ const struct sched_class stop_sched_class = {
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_stop,
.set_cpus_allowed = set_cpus_allowed_common,
#endif
.set_curr_task = set_curr_task_stop,
......
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