The following commit has been merged into the timers/core branch of tip:
Commit-ID: 679f8484cafa08f49a19e2947d05e96321fbed9d
Gitweb: https://git.kernel.org/tip/679f8484cafa08f49a19e2947d05e96321fbed9d
Author: Frederic Weisbecker <frederic@xxxxxxxxxx>
AuthorDate: Tue, 29 Oct 2024 13:54:42 +01:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Wed, 30 Oct 2024 21:02:21 +01:00
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 <frederic@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20241029125451.54574-2-frederic@xxxxxxxxxx
---
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 78c7bd6..4af2799 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);
|