Merge branch 'timers.2014.02.25a' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / kernel / timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index b75e7893be14ee80638f18f08486bf129c9018ac..a71bdfdb51e7a047f0f220816403b5b838e5c5d0 100644 (file)
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -81,6 +81,7 @@ struct tvec_base {
        unsigned long timer_jiffies;
        unsigned long next_timer;
        unsigned long active_timers;
+       unsigned long all_timers;
        struct tvec_root tv1;
        struct tvec tv2;
        struct tvec tv3;
@@ -337,6 +338,20 @@ void set_timer_slack(struct timer_list *timer, int slack_hz)
 }
 EXPORT_SYMBOL_GPL(set_timer_slack);
 
+/*
+ * If the list is empty, catch up ->timer_jiffies to the current time.
+ * The caller must hold the tvec_base lock.  Returns true if the list
+ * was empty and therefore ->timer_jiffies was updated.
+ */
+static bool catchup_timer_jiffies(struct tvec_base *base)
+{
+       if (!base->all_timers) {
+               base->timer_jiffies = jiffies;
+               return true;
+       }
+       return false;
+}
+
 static void
 __internal_add_timer(struct tvec_base *base, struct timer_list *timer)
 {
@@ -383,15 +398,17 @@ __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
         */
        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++;
 }
 
 #ifdef CONFIG_TIMER_STATS
@@ -671,6 +688,8 @@ detach_expired_timer(struct timer_list *timer, struct tvec_base *base)
        detach_timer(timer, true);
        if (!tbase_get_deferrable(timer->base))
                base->active_timers--;
+       base->all_timers--;
+       (void)catchup_timer_jiffies(base);
 }
 
 static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
@@ -685,6 +704,8 @@ static int detach_if_pending(struct timer_list *timer, struct tvec_base *base,
                if (timer->expires == base->next_timer)
                        base->next_timer = base->timer_jiffies;
        }
+       base->all_timers--;
+       (void)catchup_timer_jiffies(base);
        return 1;
 }
 
@@ -1153,6 +1174,10 @@ static inline void __run_timers(struct tvec_base *base)
        struct timer_list *timer;
 
        spin_lock_irq(&base->lock);
+       if (catchup_timer_jiffies(base)) {
+               spin_unlock_irq(&base->lock);
+               return;
+       }
        while (time_after_eq(jiffies, base->timer_jiffies)) {
                struct list_head work_list;
                struct list_head *head = &work_list;
@@ -1566,6 +1591,7 @@ static int init_timers_cpu(int cpu)
        base->timer_jiffies = jiffies;
        base->next_timer = base->timer_jiffies;
        base->active_timers = 0;
+       base->all_timers = 0;
        return 0;
 }