diff options
author | John Stultz <johnstul@us.ibm.com> | 2012-07-10 18:43:19 -0400 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2012-07-11 23:34:37 +0200 |
commit | f55a6faa384304c89cfef162768e88374d3312cb (patch) | |
tree | 522b895184e6ff0ff935d5b883eb67f8ea45e993 /kernel | |
parent | 055c9fa8874fa7261eec7a268366565db84af474 (diff) | |
download | linux-f55a6faa384304c89cfef162768e88374d3312cb.tar.bz2 |
hrtimer: Provide clock_was_set_delayed()
clock_was_set() cannot be called from hard interrupt context because
it calls on_each_cpu().
For fixing the widely reported leap seconds issue it is necessary to
call it from hard interrupt context, i.e. the timer tick code, which
does the timekeeping updates.
Provide a new function which denotes it in the hrtimer cpu base
structure of the cpu on which it is called and raise the hrtimer
softirq. We then execute the clock_was_set() notificiation from
softirq context in run_hrtimer_softirq(). The hrtimer softirq is
rarely used, so polling the flag there is not a performance issue.
[ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get
rid of all this ifdeffery ASAP ]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Reported-by: Jan Engelhardt <jengelh@inai.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1341960205-56738-2-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/hrtimer.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index ae34bf51682b..3c24fb2c25c8 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -717,6 +717,19 @@ static int hrtimer_switch_to_hres(void) return 1; } +/* + * Called from timekeeping code to reprogramm the hrtimer interrupt + * device. If called from the timer interrupt context we defer it to + * softirq context. + */ +void clock_was_set_delayed(void) +{ + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + + cpu_base->clock_was_set = 1; + __raise_softirq_irqoff(HRTIMER_SOFTIRQ); +} + #else static inline int hrtimer_hres_active(void) { return 0; } @@ -1395,6 +1408,13 @@ void hrtimer_peek_ahead_timers(void) static void run_hrtimer_softirq(struct softirq_action *h) { + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + + if (cpu_base->clock_was_set) { + cpu_base->clock_was_set = 0; + clock_was_set(); + } + hrtimer_peek_ahead_timers(); } |