From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com>
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>
---
kernel/timer.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/timer.c b/kernel/timer.c
index bdd1c00ec4ec..b49d2d0e879e 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -749,6 +749,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
base = lock_timer_base(timer, &flags);
+ (void)catchup_timer_jiffies(base);
ret = detach_if_pending(timer, base, false);
if (!ret && pending_only)
goto out_unlock;
--
1.8.1.5
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