| From 0315c1f8b9a64721941baef520ae59aee613774a Mon Sep 17 00:00:00 2001 |
| From: Scott Wood <swood@redhat.com> |
| Date: Sat, 11 Jan 2020 04:53:38 -0500 |
| Subject: [PATCH] sched/core: Don't skip remote tick for idle CPUs |
| |
| commit 488603b815a7514c7009e6fc339d74ed4a30f343 upstream. |
| |
| 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 |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/kernel/sched/core.c b/kernel/sched/core.c |
| index c36452443381..2b7021c55a21 100644 |
| --- a/kernel/sched/core.c |
| +++ b/kernel/sched/core.c |
| @@ -3102,22 +3102,24 @@ 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: |
| -- |
| 2.7.4 |
| |
