Commit 2ea97b76 authored Feb 07, 2025 by Thomas Gleixner

hrtimers: Make hrtimer_update_function() less expensive



The sanity checks in hrtimer_update_function() are expensive for high
frequency usage like in the io/uring code due to locking.

Hide the sanity checks behind CONFIG_PROVE_LOCKING, which has a decent
chance to be enabled on a regular basis for testing.

Fixes: 8f02e356 ("hrtimers: Introduce hrtimer_update_function()")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/87ikpllali.ffs@tglx

parent a64dcfb4

include/linux/hrtimer.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -333,6 +333,7 @@ static inline int hrtimer_callback_running(struct hrtimer *timer)
		static inline void hrtimer_update_function(struct hrtimer *timer,
		enum hrtimer_restart (function)(struct hrtimer ))
		{
		#ifdef CONFIG_PROVE_LOCKING
		guard(raw_spinlock_irqsave)(&timer->base->cpu_base->lock);

		if (WARN_ON_ONCE(hrtimer_is_queued(timer)))
		@@ -340,7 +341,7 @@ static inline void hrtimer_update_function(struct hrtimer *timer,

		if (WARN_ON_ONCE(!function))
		return;

		#endif
		timer->function = function;
		}