[PATCH v7 09/21] timer: add_timer_on(): Make sure TIMER_PINNED flag is set

Anna-Maria Behnsen posted 21 patches 2 years, 8 months ago
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[PATCH v7 09/21] timer: add_timer_on(): Make sure TIMER_PINNED flag is set
Posted by Anna-Maria Behnsen 2 years, 8 months ago
When adding a timer to the timer wheel using add_timer_on(), it is an
implicitly pinned timer. With the timer pull at expiry time model in place,
TIMER_PINNED flag is required to make sure timers end up in proper base.

Add TIMER_PINNED flag unconditionally when add_timer_on() is executed.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
 kernel/time/timer.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index ab9a8bb11a8a..b7599216d183 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1281,7 +1281,10 @@ EXPORT_SYMBOL(add_timer_global);
  * @timer:	The timer to be started
  * @cpu:	The CPU to start it on
  *
- * Same as add_timer() except that it starts the timer on the given CPU.
+ * Same as add_timer() except that it starts the timer on the given CPU and
+ * the TIMER_PINNED flag is set. When timer shouldn't be a pinned timer in
+ * the next round, add_timer_global() should be used instead as it unsets
+ * the TIMER_PINNED flag.
  *
  * See add_timer() for further details.
  */
@@ -1295,6 +1298,9 @@ void add_timer_on(struct timer_list *timer, int cpu)
 	if (WARN_ON_ONCE(timer_pending(timer)))
 		return;
 
+	/* Make sure timer flags have TIMER_PINNED flag set */
+	timer->flags |= TIMER_PINNED;
+
 	new_base = get_timer_cpu_base(timer->flags, cpu);
 
 	/*
-- 
2.30.2
Re: [PATCH v7 09/21] timer: add_timer_on(): Make sure TIMER_PINNED flag is set
Posted by Frederic Weisbecker 2 years, 8 months ago
Le Wed, May 24, 2023 at 09:06:17AM +0200, Anna-Maria Behnsen a écrit :
> When adding a timer to the timer wheel using add_timer_on(), it is an
> implicitly pinned timer. With the timer pull at expiry time model in place,
> TIMER_PINNED flag is required to make sure timers end up in proper base.
> 
> Add TIMER_PINNED flag unconditionally when add_timer_on() is executed.
> 
> Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>

So, as in v6 obviously:

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>