1 files changed, 98 insertions, 18 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 421be5fe5cc7..cdec83e722fa 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -300,11 +300,10 @@ EXPORT_SYMBOL_GPL(ktime_sub_ns);
  */
 u64 ktime_divns(const ktime_t kt, s64 div)
 {
-	u64 dclc, inc, dns;
+	u64 dclc;
 	int sft = 0;
 
-	dclc = dns = ktime_to_ns(kt);
-	inc = div;
+	dclc = ktime_to_ns(kt);
 	/* Make sure the divisor is less than 2^32: */
 	while (div >> 32) {
 		sft++;
@@ -623,7 +622,7 @@ static void retrigger_next_event(void *arg)
 void clock_was_set(void)
 {
 	/* Retrigger the CPU local events everywhere */
-	on_each_cpu(retrigger_next_event, NULL, 0, 1);
+	on_each_cpu(retrigger_next_event, NULL, 1);
 }
 
 /*
@@ -632,8 +631,6 @@ void clock_was_set(void)
  */
 void hres_timers_resume(void)
 {
-	WARN_ON_ONCE(num_online_cpus() > 1);
-
 	/* Retrigger the CPU local events: */
 	retrigger_next_event(NULL);
 }
@@ -675,13 +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;
@@ -1003,10 +1001,18 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
 	 */
 	raise = timer->state == HRTIMER_STATE_PENDING;
 
+	/*
+	 * We use preempt_disable to prevent this task from migrating after
+	 * setting up the softirq and raising it. Otherwise, if me migrate
+	 * we will raise the softirq on the wrong CPU.
+	 */
+	preempt_disable();
+
 	unlock_hrtimer_base(timer, &flags);
 
 	if (raise)
 		hrtimer_raise_softirq();
+	preempt_enable();
 
 	return ret;
 }
@@ -1078,7 +1084,7 @@ ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
 }
 EXPORT_SYMBOL_GPL(hrtimer_get_remaining);
 
-#if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ)
+#ifdef CONFIG_NO_HZ
 /**
  * hrtimer_get_next_event - get the time until next expiry event
  *
@@ -1240,7 +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.
@@ -1447,7 +1454,7 @@ 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
 }
 
@@ -1586,29 +1593,95 @@ 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);
@@ -1621,14 +1694,21 @@ static void migrate_hrtimers(int cpu)
 	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();
 	put_cpu_var(hrtimer_bases);
+
+	if (raise)
+		hrtimer_raise_softirq();
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
@@ -1669,7 +1749,7 @@ void __init hrtimers_init(void)
 			  (void *)(long)smp_processor_id());
 	register_cpu_notifier(&hrtimers_nb);
 #ifdef CONFIG_HIGH_RES_TIMERS
-	open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
+	open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
 #endif
 }