From 895bdfa793f6e912d1a58fc445b3dd4d686f7bd3 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 14 Apr 2015 21:08:49 +0000 Subject: hrtimer: Keep pointer to first timer and simplify __remove_hrtimer() __remove_hrtimer() needs to evaluate the expiry time to figure out whether the timer which is removed is eventually the first expiring timer on the cpu. Keep a pointer to it, which is lazily updated, so we can avoid the evaluation dance and retrieve the information from there. Generates slightly better code. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Cc: Preeti U Murthy Cc: Viresh Kumar Cc: Marcelo Tosatti Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/20150414203501.752838019@linutronix.de Signed-off-by: Thomas Gleixner --- include/linux/hrtimer.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index e5c22d611850..d194c1dacdaa 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -172,6 +172,7 @@ enum hrtimer_base_type { * @clock_was_set_seq: Sequence counter of clock was set events * @expires_next: absolute time of the next event which was scheduled * via clock_set_next_event() + * @next_timer: Pointer to the first expiring timer * @in_hrtirq: hrtimer_interrupt() is currently executing * @hres_active: State of high resolution mode * @hang_detected: The last hrtimer interrupt detected a hang @@ -180,6 +181,10 @@ enum hrtimer_base_type { * @nr_hangs: Total number of hrtimer interrupt hangs * @max_hang_time: Maximum time spent in hrtimer_interrupt * @clock_base: array of clock bases for this cpu + * + * Note: next_timer is just an optimization for __remove_hrtimer(). + * Do not dereference the pointer because it is not reliable on + * cross cpu removals. */ struct hrtimer_cpu_base { raw_spinlock_t lock; @@ -191,6 +196,7 @@ struct hrtimer_cpu_base { hres_active : 1, hang_detected : 1; ktime_t expires_next; + struct hrtimer *next_timer; unsigned int nr_events; unsigned int nr_retries; unsigned int nr_hangs; -- cgit v1.2.3