Messages in this thread | | | Subject | Re: [PATCH] tick/nohz: Make the idle_exittime update correctly | From | Yunfeng Ye <> | Date | Thu, 17 Dec 2020 14:51:58 +0800 |
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On 2020/12/15 22:47, Frederic Weisbecker wrote: > On Tue, Dec 15, 2020 at 08:06:34PM +0800, Yunfeng Ye wrote: >> The idle_exittime field of tick_sched is used to record the time when >> the idle state was left. but currently the idle_exittime is updated in >> the function tick_nohz_restart_sched_tick(), which is not always in idle >> state when nohz_full is configured. >> >> tick_irq_exit >> tick_nohz_irq_exit >> tick_nohz_full_update_tick >> tick_nohz_restart_sched_tick >> ts->idle_exittime = now; >> >> So move to tick_nohz_stop_idle() to make the idle_exittime update >> correctly. >> >> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> >> --- >> kernel/time/tick-sched.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c >> index 749ec2a583de..be2e5d772d50 100644 >> --- a/kernel/time/tick-sched.c >> +++ b/kernel/time/tick-sched.c >> @@ -591,6 +591,7 @@ static void tick_nohz_stop_idle(struct tick_sched *ts, ktime_t now) >> { >> update_ts_time_stats(smp_processor_id(), ts, now, NULL); >> ts->idle_active = 0; >> + ts->idle_exittime = now; > > This changes a bit the meaning of idle_exittime then since this is also called > from idle interrupt entry. > > __tick_nohz_idle_restart_tick() would be a better place. > So is it necessary to modify the comment "@idle_exittime: Time when the idle state was left" ?
On the other hand, if the patch "nohz: Update tick instead of restarting tick in tick_nohz_idle_exit()" (https://www.spinics.net/lists/kernel/msg3747039.html ) applied, __tick_nohz_idle_restart_tick will not be called always, So is it put here also a better place?
Thanks.
> Thanks. > >> >> sched_clock_idle_wakeup_event(); >> } >> @@ -901,7 +902,6 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now) >> * Cancel the scheduled timer and restore the tick >> */ >> ts->tick_stopped = 0; >> - ts->idle_exittime = now; >> >> tick_nohz_restart(ts, now); >> } >> -- >> 2.18.4 >> > . >
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