Messages in this thread Patch in this message | | | From | Anna-Maria Behnsen <> | Subject | [PATCH v8 11/25] timers: Introduce add_timer() variants which modify timer flags | Date | Wed, 4 Oct 2023 14:34:40 +0200 |
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Timer might be used as pinned timer (using add_timer_on()) and later on as non pinned timers using add_timer(). When the NOHZ timer pull at expiry model is in place, TIMER_PINNED flag is required to be used whenever a timer needs to expire on a dedicated CPU. Flag must no be set, if expiration on a dedicated CPU is not required.
add_timer_on()'s behavior will be changed during the preparation patches for the NOHZ timer pull at expiry model to unconditionally set TIMER_PINNED flag. To be able to reset/set the flag when queueing a timer, two variants of add_timer() are introduced.
This is a preparatory patch and has no functional change.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> --- New in v6 --- include/linux/timer.h | 2 ++ kernel/time/timer.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+)
diff --git a/include/linux/timer.h b/include/linux/timer.h index 9162f275819a..6f96661480dd 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -180,6 +180,8 @@ extern int timer_reduce(struct timer_list *timer, unsigned long expires); #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1) extern void add_timer(struct timer_list *timer); +extern void add_timer_local(struct timer_list *timer); +extern void add_timer_global(struct timer_list *timer); extern int try_to_del_timer_sync(struct timer_list *timer); extern int timer_delete_sync(struct timer_list *timer); diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 8518f7aa7319..3172b8094097 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1245,6 +1245,40 @@ void add_timer(struct timer_list *timer) } EXPORT_SYMBOL(add_timer); +/** + * add_timer_local - Start a timer on the local CPU + * @timer: The timer to be started + * + * Same as add_timer() except that the timer flag TIMER_PINNED is set. + * + * See add_timer() for further details. + */ +void add_timer_local(struct timer_list *timer) +{ + if (WARN_ON_ONCE(timer_pending(timer))) + return; + timer->flags |= TIMER_PINNED; + __mod_timer(timer, timer->expires, MOD_TIMER_NOTPENDING); +} +EXPORT_SYMBOL(add_timer_local); + +/** + * add_timer_global - Start a timer without TIMER_PINNED flag set + * @timer: The timer to be started + * + * Same as add_timer() except that the timer flag TIMER_PINNED is unset. + * + * See add_timer() for further details. + */ +void add_timer_global(struct timer_list *timer) +{ + if (WARN_ON_ONCE(timer_pending(timer))) + return; + timer->flags &= ~TIMER_PINNED; + __mod_timer(timer, timer->expires, MOD_TIMER_NOTPENDING); +} +EXPORT_SYMBOL(add_timer_global); + /** * add_timer_on - Start a timer on a particular CPU * @timer: The timer to be started -- 2.39.2
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