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authorJeff Ohlstein <johlstei@codeaurora.org>2011-11-18 18:47:10 -0500
committerThomas Gleixner <tglx@linutronix.de>2011-11-19 06:17:37 -0500
commit27c9cd7e601632b3794e1c3344d37b86917ffb43 (patch)
treedc6f3d9accdf9c7fd8fd80dd81ff2ed7e07304e7 /kernel
parentd004e024058a0eaca097513ce62cbcf978913e0a (diff)
hrtimer: Fix extra wakeups from __remove_hrtimer()
__remove_hrtimer() attempts to reprogram the clockevent device when the timer being removed is the next to expire. However, __remove_hrtimer() reprograms the clockevent *before* removing the timer from the timerqueue and thus when hrtimer_force_reprogram() finds the next timer to expire it finds the timer we're trying to remove. This is especially noticeable when the system switches to NOHz mode and the system tick is removed. The timer tick is removed from the system but the clockevent is programmed to wakeup in another HZ anyway. Silence the extra wakeup by removing the timer from the timerqueue before calling hrtimer_force_reprogram() so that we actually program the clockevent for the next timer to expire. This was broken by 998adc3 "hrtimers: Convert hrtimers to use timerlist infrastructure". Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1321660030-8520-1-git-send-email-johlstei@codeaurora.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/hrtimer.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index a9205e32a059..2043c08d36c8 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -885,10 +885,13 @@ static void __remove_hrtimer(struct hrtimer *timer,
885 struct hrtimer_clock_base *base, 885 struct hrtimer_clock_base *base,
886 unsigned long newstate, int reprogram) 886 unsigned long newstate, int reprogram)
887{ 887{
888 struct timerqueue_node *next_timer;
888 if (!(timer->state & HRTIMER_STATE_ENQUEUED)) 889 if (!(timer->state & HRTIMER_STATE_ENQUEUED))
889 goto out; 890 goto out;
890 891
891 if (&timer->node == timerqueue_getnext(&base->active)) { 892 next_timer = timerqueue_getnext(&base->active);
893 timerqueue_del(&base->active, &timer->node);
894 if (&timer->node == next_timer) {
892#ifdef CONFIG_HIGH_RES_TIMERS 895#ifdef CONFIG_HIGH_RES_TIMERS
893 /* Reprogram the clock event device. if enabled */ 896 /* Reprogram the clock event device. if enabled */
894 if (reprogram && hrtimer_hres_active()) { 897 if (reprogram && hrtimer_hres_active()) {
@@ -901,7 +904,6 @@ static void __remove_hrtimer(struct hrtimer *timer,
901 } 904 }
902#endif 905#endif
903 } 906 }
904 timerqueue_del(&base->active, &timer->node);
905 if (!timerqueue_getnext(&base->active)) 907 if (!timerqueue_getnext(&base->active))
906 base->cpu_base->active_bases &= ~(1 << base->index); 908 base->cpu_base->active_bases &= ~(1 << base->index);
907out: 909out: