[PATCH AUTOSEL 5.5 03/58] sched/core: Don't skip remote tick for idle CPUs
From: Sasha Levin <sashal@kernel.org>
Date: 2020-02-23 02:21:29
Also in:
lkml
Subsystem:
scheduler, the rest · Maintainers:
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
From: Scott Wood <redacted> [ Upstream commit 488603b815a7514c7009e6fc339d74ed4a30f343 ] 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 <redacted> 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 Signed-off-by: Sasha Levin <sashal@kernel.org> --- kernel/sched/core.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 894fb81313fd1..ee3685385a6a3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c@@ -3668,22 +3668,24 @@ 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; - /* - * Make sure the next tick runs within a reasonable - * amount of time. - */ - WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3); + 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:
--
2.20.1