3.12.38-rt53-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
upstream commit: 18d8cb64c9c074cbe2bd677ab10fff8283abdb62
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 <paul...@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <j...@joshtriplett.org>
Acked-by: Peter Zijlstra <pet...@infradead.org>
Reviewed-by: Oleg Nesterov <o...@redhat.com>
Reviewed-by: Steven Rostedt <rost...@goodmis.org>
Tested-by: Mike Galbraith <bitbuc...@online.de>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
kernel/timer.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/timer.c b/kernel/timer.c
index c3017c06f212..0ee72212b99c 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -401,6 +401,7 @@ __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
--
2.1.4
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