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);
}
/**
|