hrtimer: Provide clock_was_set_delayed()
authorJohn Stultz <johnstul@us.ibm.com>
Tue, 10 Jul 2012 22:43:19 +0000 (18:43 -0400)
committerThomas Gleixner <tglx@linutronix.de>
Wed, 11 Jul 2012 21:34:37 +0000 (23:34 +0200)
commitf55a6faa384304c89cfef162768e88374d3312cb
tree522b895184e6ff0ff935d5b883eb67f8ea45e993
parent055c9fa8874fa7261eec7a268366565db84af474
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>
include/linux/hrtimer.h
kernel/hrtimer.c