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hrtimer: Use hrtimer_start_expires_user() for hrtimer sleepers

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Most hrtimer sleepers are user controlled and user space can hand arbitrary
expiry values in as long as they are valid timespecs. If the expiry value
is in the past then this requires a full loop through reprogramming the
clock event device, taking the hrtimer interrupt, waking the task and
reprogram again.

Use hrtimer_start_expires_user() which avoids the full round trip by
checking the timer for expiry on enqueue.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Calvin Owens <calvin@wbinvd.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260408114952.062400833@kernel.org
This commit is contained in:
Thomas Gleixner
2026-04-08 13:53:52 +02:00
parent bd5956166d
commit b40c927345
1 changed files with 5 additions and 1 deletions
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6
kernel/time/hrtimer.c
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@@ -2315,7 +2315,11 @@ void hrtimer_sleeper_start_expires(struct hrtimer_sleeper *sl, enum hrtimer_mode
if (IS_ENABLED(CONFIG_PREEMPT_RT) && sl->timer.is_hard)
mode |= HRTIMER_MODE_HARD;
hrtimer_start_expires(&sl->timer, mode);
/* If already expired, clear the task pointer and set current state to running */
if (!hrtimer_start_expires_user(&sl->timer, mode)) {
sl->task = NULL;
__set_current_state(TASK_RUNNING);
}
}
EXPORT_SYMBOL_GPL(hrtimer_sleeper_start_expires);