The following commit has been merged into the timers/nohz branch of tip: Commit-ID: 96c9b90396f9ab6caf13b4ebf00095818ac53b7f Gitweb: https://git.kernel.org/tip/96c9b90396f9ab6caf13b4ebf00095818ac53b7f Author: Yunfeng Ye <yeyunfeng@xxxxxxxxxx> AuthorDate: Thu, 13 May 2021 01:29:18 +02:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Thu, 13 May 2021 14:21:21 +02:00 tick/nohz: Update idle_exittime on actual idle exit 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; It's thus overwritten by mistake on nohz_full tick restart. Move the update to the appropriate idle exit path instead. Signed-off-by: Yunfeng Ye <yeyunfeng@xxxxxxxxxx> Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210512232924.150322-5-frederic@xxxxxxxxxx --- kernel/time/tick-sched.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 1afa759..89ec0ab 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -921,8 +921,6 @@ 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); } @@ -1194,10 +1192,13 @@ unsigned long tick_nohz_get_idle_calls(void) return ts->idle_calls; } -static void tick_nohz_account_idle_ticks(struct tick_sched *ts) +static void tick_nohz_account_idle_time(struct tick_sched *ts, + ktime_t now) { unsigned long ticks; + ts->idle_exittime = now; + if (vtime_accounting_enabled_this_cpu()) return; /* @@ -1218,8 +1219,9 @@ void tick_nohz_idle_restart_tick(void) struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); if (ts->tick_stopped) { - tick_nohz_restart_sched_tick(ts, ktime_get()); - tick_nohz_account_idle_ticks(ts); + ktime_t now = ktime_get(); + tick_nohz_restart_sched_tick(ts, now); + tick_nohz_account_idle_time(ts, now); } } @@ -1230,7 +1232,7 @@ static void tick_nohz_idle_update_tick(struct tick_sched *ts, ktime_t now) else tick_nohz_restart_sched_tick(ts, now); - tick_nohz_account_idle_ticks(ts); + tick_nohz_account_idle_time(ts, now); } /**
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