sched/core: Streamle calls to task_rq_unlock() (4b211f2b) · Commits · 戴 / test

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>

kernel/sched/core.c

+14 −10

Original line number	Diff line number	Diff line
		@@ -4712,8 +4712,8 @@ recheck:
		* 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 @@ recheck:
		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 @@ change:
		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 @@ change:
		*/
		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 @@ change:
		* 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 @@ change:
		preempt_enable();

		return 0;

		unlock:
		task_rq_unlock(rq, p, &rf);
		return retval;
		}

		static int _sched_setscheduler(struct task_struct *p, int policy,

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