Messages in this thread Patch in this message | | | Date | Tue, 27 Apr 2021 10:25:40 +0200 | From | Thomas Gleixner <> | Subject | [patch 3/8] timerfd: Provide timerfd_resume() |
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Resuming timekeeping is a clock-was-set event and uses the clock-was-set notification mechanism. This is in the way of making the clock-was-set update for hrtimers selective so unnecessary IPIs are avoided when a CPU base does not have timers queued which are affected by the clock setting.
Provide a seperate timerfd_resume() interface so the resume logic and the clock-was-set mechanism can be distangled in the core code.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- fs/timerfd.c | 16 ++++++++++++++++ include/linux/hrtimer.h | 2 ++ 2 files changed, 18 insertions(+)
--- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -115,6 +115,22 @@ void timerfd_clock_was_set(void) rcu_read_unlock(); } +static void timerfd_resume_work(struct work_struct *work) +{ + timerfd_clock_was_set(); +} + +static DECLARE_WORK(timerfd_work, timerfd_resume_work); + +/* + * Invoked from timekeeping_resume(). Defer the actual update to work so + * timerfd_clock_was_set() runs in task context. + */ +void timerfd_resume(void) +{ + schedule_work(&timerfd_work); +} + static void __timerfd_remove_cancel(struct timerfd_ctx *ctx) { if (ctx->might_cancel) { --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -349,8 +349,10 @@ hrtimer_expires_remaining_adjusted(const #ifdef CONFIG_TIMERFD extern void timerfd_clock_was_set(void); +extern void timerfd_resume(void); #else static inline void timerfd_clock_was_set(void) { } +static inline void timerfd_resume(void) { } #endif extern void hrtimers_resume(void);
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