1 files changed, 92 insertions, 18 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index b8e4dce80a7..95978f48e03 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -672,13 +672,14 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
                          */
                         BUG_ON(timer->function(timer) != HRTIMER_NORESTART);
                         return 1;
-                case HRTIMER_CB_IRQSAFE_NO_SOFTIRQ:
+                case HRTIMER_CB_IRQSAFE_PERCPU:
+                case HRTIMER_CB_IRQSAFE_UNLOCKED:
                         /*
                          * This is solely for the sched tick emulation with
                          * dynamic tick support to ensure that we do not
                          * restart the tick right on the edge and end up with
                          * the tick timer in the softirq ! The calling site
-                         * takes care of this.
+                         * takes care of this. Also used for hrtimer sleeper !
                          */
                         debug_hrtimer_deactivate(timer);
                         return 1;
@@ -1245,7 +1246,8 @@ static void __run_hrtimer(struct hrtimer *timer)
         timer_stats_account_hrtimer(timer);
 
         fn = timer->function;
-        if (timer->cb_mode == HRTIMER_CB_IRQSAFE_NO_SOFTIRQ) {
+        if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
+            timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED) {
                 /*
                  * Used for scheduler timers, avoid lock inversion with
                  * rq->lock and tasklist_lock.
@@ -1401,9 +1403,7 @@ void hrtimer_run_queues(void)
                 if (!base->first)
                         continue;
 
-                if (base->get_softirq_time)
-                        base->softirq_time = base->get_softirq_time();
-                else if (gettime) {
+                if (gettime) {
                         hrtimer_get_softirq_time(cpu_base);
                         gettime = 0;
                 }
@@ -1452,7 +1452,7 @@ void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
         sl->timer.function = hrtimer_wakeup;
         sl->task = task;
 #ifdef CONFIG_HIGH_RES_TIMERS
-        sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+        sl->timer.cb_mode = HRTIMER_CB_IRQSAFE_UNLOCKED;
 #endif
 }
 
@@ -1591,49 +1591,123 @@ static void __cpuinit init_hrtimers_cpu(int cpu)
 
 #ifdef CONFIG_HOTPLUG_CPU
 
-static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
-                                struct hrtimer_clock_base *new_base)
+static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+                                struct hrtimer_clock_base *new_base, int dcpu)
 {
         struct hrtimer *timer;
         struct rb_node *node;
+        int raise = 0;
 
         while ((node = rb_first(&old_base->active))) {
                 timer = rb_entry(node, struct hrtimer, node);
                 BUG_ON(hrtimer_callback_running(timer));
                 debug_hrtimer_deactivate(timer);
-                __remove_hrtimer(timer, old_base, HRTIMER_STATE_INACTIVE, 0);
+
+                /*
+                 * Should not happen. Per CPU timers should be
+                 * canceled _before_ the migration code is called
+                 */
+                if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU) {
+                        __remove_hrtimer(timer, old_base,
+                                         HRTIMER_STATE_INACTIVE, 0);
+                        WARN(1, "hrtimer (%p %p)active but cpu %d dead\n",
+                             timer, timer->function, dcpu);
+                        continue;
+                }
+
+                /*
+                 * Mark it as STATE_MIGRATE not INACTIVE otherwise the
+                 * timer could be seen as !active and just vanish away
+                 * under us on another CPU
+                 */
+                __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
                 timer->base = new_base;
                 /*
                  * Enqueue the timer. Allow reprogramming of the event device
                  */
                 enqueue_hrtimer(timer, new_base, 1);
+
+#ifdef CONFIG_HIGH_RES_TIMERS
+                /*
+                 * Happens with high res enabled when the timer was
+                 * already expired and the callback mode is
+                 * HRTIMER_CB_IRQSAFE_UNLOCKED (hrtimer_sleeper). The
+                 * enqueue code does not move them to the soft irq
+                 * pending list for performance/latency reasons, but
+                 * in the migration state, we need to do that
+                 * otherwise we end up with a stale timer.
+                 */
+                if (timer->state == HRTIMER_STATE_MIGRATE) {
+                        timer->state = HRTIMER_STATE_PENDING;
+                        list_add_tail(&timer->cb_entry,
+                                      &new_base->cpu_base->cb_pending);
+                        raise = 1;
+                }
+#endif
+                /* Clear the migration state bit */
+                timer->state &= ~HRTIMER_STATE_MIGRATE;
         }
+        return raise;
 }
 
+#ifdef CONFIG_HIGH_RES_TIMERS
+static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
+                                   struct hrtimer_cpu_base *new_base)
+{
+        struct hrtimer *timer;
+        int raise = 0;
+
+        while (!list_empty(&old_base->cb_pending)) {
+                timer = list_entry(old_base->cb_pending.next,
+                                   struct hrtimer, cb_entry);
+
+                __remove_hrtimer(timer, timer->base, HRTIMER_STATE_PENDING, 0);
+                timer->base = &new_base->clock_base[timer->base->index];
+                list_add_tail(&timer->cb_entry, &new_base->cb_pending);
+                raise = 1;
+        }
+        return raise;
+}
+#else
+static int migrate_hrtimer_pending(struct hrtimer_cpu_base *old_base,
+                                   struct hrtimer_cpu_base *new_base)
+{
+        return 0;
+}
+#endif
+
 static void migrate_hrtimers(int cpu)
 {
         struct hrtimer_cpu_base *old_base, *new_base;
-        int i;
+        int i, raise = 0;
 
         BUG_ON(cpu_online(cpu));
         old_base = &per_cpu(hrtimer_bases, cpu);
         new_base = &get_cpu_var(hrtimer_bases);
 
         tick_cancel_sched_timer(cpu);
-
-        local_irq_disable();
-        spin_lock(&new_base->lock);
+        /*
+         * The caller is globally serialized and nobody else
+         * takes two locks at once, deadlock is not possible.
+         */
+        spin_lock_irq(&new_base->lock);
         spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
         for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
-                migrate_hrtimer_list(&old_base->clock_base[i],
-                                     &new_base->clock_base[i]);
+                if (migrate_hrtimer_list(&old_base->clock_base[i],
+                                         &new_base->clock_base[i], cpu))
+                        raise = 1;
         }
 
+        if (migrate_hrtimer_pending(old_base, new_base))
+                raise = 1;
+
         spin_unlock(&old_base->lock);
-        spin_unlock(&new_base->lock);
-        local_irq_enable();
+        spin_unlock_irq(&new_base->lock);
         put_cpu_var(hrtimer_bases);
+
+        if (raise)
+                hrtimer_raise_softirq();
 }
 #endif /* CONFIG_HOTPLUG_CPU */