timers: Make internal_add_timer() update ->next_timer if ->active_timers == 0

The internal_add_timer() function updates base->next_timer only if
timer->expires < base->next_timer. This is correct, but it also makes
sense to do the same if we add the first non-deferrable timer.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
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>
Tested-by: Mike Galbraith <bitbucket@online.de>

diff --git a/kernel/timer.c b/kernel/timer.c
index 0c638cf..c0d8898 100644 (file)
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -404,9 +404,9 @@ static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
         * Update base->active_timers and base->next_timer
         */
        if (!tbase_get_deferrable(timer->base)) {
-               if (time_before(timer->expires, base->next_timer))
+               if (!base->active_timers++ ||
+                   time_before(timer->expires, base->next_timer))
                        base->next_timer = timer->expires;
-               base->active_timers++;
        }
        base->all_timers++;
 }