timers: Sanitize catchup_timer_jiffies() usage
authorThomas Gleixner <tglx@linutronix.de>
Tue, 26 May 2015 22:50:24 +0000 (22:50 +0000)
committerThomas Gleixner <tglx@linutronix.de>
Fri, 19 Jun 2015 13:18:27 +0000 (15:18 +0200)
commit3bb475a3446facd0425d3f2fe7e85bf03c5c6c05
tree0b7af9596cdac5bb89bd2f3ad70e0f26a615b706
parent887d9dc989eb0154492e41e7c07492edbb088ba1
timers: Sanitize catchup_timer_jiffies() usage

catchup_timer_jiffies() has been applied blindly to several functions
without looking for possible better ways to do it.

1) internal_add_timer()

   Move the update to base->all_timers before we actually insert the
   timer into the wheel.

2) detach_if_pending()

   Again the update to base->all_timers allows us to explicitely do
   the timer_jiffies update in place, if this was the last timer which
   got removed.

3) __run_timers()

   We only check on entry, which is silly, because base->timer_jiffies
   can be behind - especially on NOHZ kernels - and if there is a
   single deferrable timer somewhere between base->timer_jiffies and
   jiffies we expire it and then loop until base->timer_jiffies ==
   jiffies.

   Move it into the loop.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224511.662994644@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
kernel/time/timer.c