• Jeff Ohlstein's avatar
    hrtimer: Fix extra wakeups from __remove_hrtimer() · 27c9cd7e
    Jeff Ohlstein authored
    __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 998adc3d "hrtimers: Convert hrtimers to use
    timerlist infrastructure".
    Signed-off-by: default avatarJeff Ohlstein <johlstei@codeaurora.org>
    Cc: stable@vger.kernel.org
    Link: http://lkml.kernel.org/r/1321660030-8520-1-git-send-email-johlstei@codeaurora.orgSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    27c9cd7e
hrtimer.c 46.4 KB