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timers/migration: Spare write when nothing changed

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The wakeup value is written unconditionally in tmigr_cpu_new_timer(). When
there was no new next timer expiry that needs to be propagated, then the
value that was read before is written. This is not required.

Move the write to the place where wakeup value is changed changed.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20240716-tmigr-fixes-v4-7-757baa7803fe@linutronix.de
This commit is contained in:
Anna-Maria Behnsen 2024-07-16 16:19:25 +02:00 committed by Thomas Gleixner
parent 835a9a67f5
commit 2367e28e23
1 changed files with 5 additions and 6 deletions
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11
kernel/time/timer_migration.c
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@ -1215,14 +1215,13 @@ u64 tmigr_cpu_new_timer(u64 nextexp)
if (nextexp != tmc->cpuevt.nextevt.expires ||
tmc->cpuevt.ignore) {
ret = tmigr_new_timer(tmc, nextexp);
/*
* Make sure the reevaluation of timers in idle path
* will not miss an event.
*/
WRITE_ONCE(tmc->wakeup, ret);
}
}
/*
* Make sure the reevaluation of timers in idle path will not miss an
* event.
*/
WRITE_ONCE(tmc->wakeup, ret);
trace_tmigr_cpu_new_timer_idle(tmc, nextexp);
raw_spin_unlock(&tmc->lock);
return ret;