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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-12-16 10:41:50 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-02-25 12:39:00 -0800 |
| commit | 18d8cb64c9c074cbe2bd677ab10fff8283abdb62 (patch) | |
| tree | b811a626f38d2b27d57e67e769bdecdc736cfac9 | |
| parent | 16d937f880312e3f47157d4d6d6ebf7e61523378 (diff) | |
| download | linux-18d8cb64c9c074cbe2bd677ab10fff8283abdb62.tar.bz2 | |
timers: Reduce future __run_timers() latency for first add to empty list
The __run_timers() function currently steps through the list one jiffy at
a time in order to update the timer wheel. However, if the timer wheel
is empty, no adjustment is needed other than updating ->timer_jiffies.
Therefore, just before we add a timer to an empty timer wheel, we should
mark the timer wheel as being up to date. This marking will reduce (and
perhaps eliminate) the jiffy-stepping that a future __run_timers() call
will need to do in response to some future timer posting or migration.
This commit therefore updates ->timer_jiffies for this case.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Mike Galbraith <bitbucket@online.de>
| -rw-r--r-- | kernel/timer.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/timer.c b/kernel/timer.c index dfac34f7186f..0c638cf3d9d2 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -398,6 +398,7 @@ __internal_add_timer(struct tvec_base *base, struct timer_list *timer) static void internal_add_timer(struct tvec_base *base, struct timer_list *timer) { + (void)catchup_timer_jiffies(base); __internal_add_timer(base, timer); /* * Update base->active_timers and base->next_timer |