Commit 17a8945f authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Thomas Gleixner
Browse files

clockevents: Improve clockevents_notify_released() comment 



When a new clockevent device is added and replaces a previous device,
the latter is put into the released list. Then the released list is
added back.

This may look counter-intuitive but the reason is that released device
might be suitable for other uses. For example a released CPU regular
clockevent can be a better replacement for the current broadcast event.
Similarly a released broadcast clockevent can be a better replacement
for the current regular clockevent of a given CPU.

Improve comments stating about these subtleties.

Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241029125451.54574-2-frederic@kernel.org
parent b35108a5

kernel/time/clockevents.c

+10 −2
Original line number Diff line number Diff line
@@ -337,13 +337,21 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, 
}



/*

 * Called after a notify add to make devices available which were

 * released from the notifier call.

 * Called after a clockevent has been added which might

 * have replaced a current regular or broadcast device. A

 * released normal device might be a suitable replacement

 * for the current broadcast device. Similarly a released

 * broadcast device might be a suitable replacement for a

 * normal device.

 */

static void clockevents_notify_released(void)

{

	struct clock_event_device *dev;



	/*

	 * Keep iterating as long as tick_check_new_device()

	 * replaces a device.

	 */

	while (!list_empty(&clockevents_released)) {

		dev = list_entry(clockevents_released.next,

				 struct clock_event_device, list);