From 17a8945f369ce2de2532ba8abdb93bb5b2d1c118 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 29 Oct 2024 13:54:42 +0100 Subject: [PATCH] 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: Frederic Weisbecker Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20241029125451.54574-2-frederic@kernel.org --- kernel/time/clockevents.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 78c7bd64d0ddf..4af27994db93c 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -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);