sched/core: Don't skip remote tick for idle CPUs (488603b8) · Commits · 戴 / test

This will be used in the next patch to get a loadavg update from nohz cpus. The delta check is skipped because idle_sched_class doesn't update se.exec_start. Signed-off-by:

Scott Wood <swood@redhat.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by:

Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/1578736419-14628-2-git-send-email-swood@redhat.com

kernel/sched/core.c

+10 −8

Original line number	Diff line number	Diff line
		@@ -3669,22 +3669,24 @@ static void sched_tick_remote(struct work_struct *work)
		* statistics and checks timeslices in a time-independent way, regardless
		* of when exactly it is running.
		*/
		if (idle_cpu(cpu) \|\| !tick_nohz_tick_stopped_cpu(cpu))
		if (!tick_nohz_tick_stopped_cpu(cpu))
		goto out_requeue;

		rq_lock_irq(rq, &rf);
		curr = rq->curr;
		if (is_idle_task(curr) \|\| cpu_is_offline(cpu))
		if (cpu_is_offline(cpu))
		goto out_unlock;

		update_rq_clock(rq);
		delta = rq_clock_task(rq) - curr->se.exec_start;

		if (!is_idle_task(curr)) {
		/*
		* Make sure the next tick runs within a reasonable
		* amount of time.
		*/
		delta = rq_clock_task(rq) - curr->se.exec_start;
		WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
		}
		curr->sched_class->task_tick(rq, curr, 0);

		out_unlock:

Admin message