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sched/core: Streamle calls to task_rq_unlock() 

Calls to task_rq_unlock() are done several times in the
__sched_setscheduler() function.  This is fine when only the rq lock needs to be
handled but not so much when other locks come into play.

This patch streamlines the release of the rq lock so that only one
location need to be modified when dealing with more than one lock.

No change of functionality is introduced by this patch.

Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-3-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Mathieu Poirier 2019-07-19 15:59:54 +02:00 committed by Ingo Molnar
parent c22645f4c8
commit 4b211f2b12
1 changed files with 14 additions and 10 deletions
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24
kernel/sched/core.c
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@ -4712,8 +4712,8 @@ static int __sched_setscheduler(struct task_struct *p,
* Changing the policy of the stop threads its a very bad idea:
*/
if (p == rq->stop) {
task_rq_unlock(rq, p, &rf);
return -EINVAL;
retval = -EINVAL;
goto unlock;
}
/*
@ -4731,8 +4731,8 @@ static int __sched_setscheduler(struct task_struct *p,
goto change;
p->sched_reset_on_fork = reset_on_fork;
task_rq_unlock(rq, p, &rf);
return 0;
retval = 0;
goto unlock;
}
change:
@ -4745,8 +4745,8 @@ static int __sched_setscheduler(struct task_struct *p,
if (rt_bandwidth_enabled() && rt_policy(policy) &&
task_group(p)->rt_bandwidth.rt_runtime == 0 &&
!task_group_is_autogroup(task_group(p))) {
task_rq_unlock(rq, p, &rf);
return -EPERM;
retval = -EPERM;
goto unlock;
}
#endif
#ifdef CONFIG_SMP
@ -4761,8 +4761,8 @@ static int __sched_setscheduler(struct task_struct *p,
*/
if (!cpumask_subset(span, p->cpus_ptr) ||
rq->rd->dl_bw.bw == 0) {
task_rq_unlock(rq, p, &rf);
return -EPERM;
retval = -EPERM;
goto unlock;
}
}
#endif
@ -4781,8 +4781,8 @@ static int __sched_setscheduler(struct task_struct *p,
* is available.
*/
if ((dl_policy(policy) || dl_task(p)) && sched_dl_overflow(p, policy, attr)) {
task_rq_unlock(rq, p, &rf);
return -EBUSY;
retval = -EBUSY;
goto unlock;
}
p->sched_reset_on_fork = reset_on_fork;
@ -4840,6 +4840,10 @@ static int __sched_setscheduler(struct task_struct *p,
preempt_enable();
return 0;
unlock:
task_rq_unlock(rq, p, &rf);
return retval;
}
static int _sched_setscheduler(struct task_struct *p, int policy,