1 files changed, 88 insertions, 302 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 47e63349d1b2..1455b7651b6b 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -32,7 +32,6 @@
  */
 
 #include <linux/cpu.h>
-#include <linux/irq.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/hrtimer.h>
@@ -442,22 +441,6 @@ static inline void debug_hrtimer_activate(struct hrtimer *timer) { }
 static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }
 #endif
 
-/*
- * Check, whether the timer is on the callback pending list
- */
-static inline int hrtimer_cb_pending(const struct hrtimer *timer)
-{
-	return timer->state & HRTIMER_STATE_PENDING;
-}
-
-/*
- * Remove a timer from the callback pending list
- */
-static inline void hrtimer_remove_cb_pending(struct hrtimer *timer)
-{
-	list_del_init(&timer->cb_entry);
-}
-
 /* High resolution timer related functions */
 #ifdef CONFIG_HIGH_RES_TIMERS
 
@@ -651,6 +634,7 @@ static inline void hrtimer_init_timer_hres(struct hrtimer *timer)
 {
 }
 
+
 /*
  * When High resolution timers are active, try to reprogram. Note, that in case
  * the state has HRTIMER_STATE_CALLBACK set, no reprogramming and no expiry
@@ -661,31 +645,10 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
 					    struct hrtimer_clock_base *base)
 {
 	if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
-
-		/* Timer is expired, act upon the callback mode */
-		switch(timer->cb_mode) {
-		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. Also used for hrtimer sleeper !
-			 */
-			debug_hrtimer_deactivate(timer);
-			return 1;
-		case HRTIMER_CB_SOFTIRQ:
-			/*
-			 * Move everything else into the softirq pending list !
-			 */
-			list_add_tail(&timer->cb_entry,
-				      &base->cpu_base->cb_pending);
-			timer->state = HRTIMER_STATE_PENDING;
-			return 1;
-		default:
-			BUG();
-		}
+		spin_unlock(&base->cpu_base->lock);
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+		spin_lock(&base->cpu_base->lock);
+		return 1;
 	}
 	return 0;
 }
@@ -724,11 +687,6 @@ static int hrtimer_switch_to_hres(void)
 	return 1;
 }
 
-static inline void hrtimer_raise_softirq(void)
-{
-	raise_softirq(HRTIMER_SOFTIRQ);
-}
-
 #else
 
 static inline int hrtimer_hres_active(void) { return 0; }
@@ -742,12 +700,6 @@ static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
 }
 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
 static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
-static inline int hrtimer_reprogram(struct hrtimer *timer,
-				    struct hrtimer_clock_base *base)
-{
-	return 0;
-}
-static inline void hrtimer_raise_softirq(void) { }
 
 #endif /* CONFIG_HIGH_RES_TIMERS */
 
@@ -818,9 +770,11 @@ EXPORT_SYMBOL_GPL(hrtimer_forward);
  *
  * The timer is inserted in expiry order. Insertion into the
  * red black tree is O(log(n)). Must hold the base lock.
+ *
+ * Returns 1 when the new timer is the leftmost timer in the tree.
  */
-static void enqueue_hrtimer(struct hrtimer *timer,
-			    struct hrtimer_clock_base *base, int reprogram)
+static int enqueue_hrtimer(struct hrtimer *timer,
+			   struct hrtimer_clock_base *base)
 {
 	struct rb_node **link = &base->active.rb_node;
 	struct rb_node *parent = NULL;
@@ -852,20 +806,8 @@ static void enqueue_hrtimer(struct hrtimer *timer,
 	 * Insert the timer to the rbtree and check whether it
 	 * replaces the first pending timer
 	 */
-	if (leftmost) {
-		/*
-		 * Reprogram the clock event device. When the timer is already
-		 * expired hrtimer_enqueue_reprogram has either called the
-		 * callback or added it to the pending list and raised the
-		 * softirq.
-		 *
-		 * This is a NOP for !HIGHRES
-		 */
-		if (reprogram && hrtimer_enqueue_reprogram(timer, base))
-			return;
-
+	if (leftmost)
 		base->first = &timer->node;
-	}
 
 	rb_link_node(&timer->node, parent, link);
 	rb_insert_color(&timer->node, &base->active);
@@ -874,6 +816,8 @@ static void enqueue_hrtimer(struct hrtimer *timer,
 	 * state of a possibly running callback.
 	 */
 	timer->state |= HRTIMER_STATE_ENQUEUED;
+
+	return leftmost;
 }
 
 /*
@@ -890,10 +834,7 @@ static void __remove_hrtimer(struct hrtimer *timer,
 			     struct hrtimer_clock_base *base,
 			     unsigned long newstate, int reprogram)
 {
-	/* High res. callback list. NOP for !HIGHRES */
-	if (hrtimer_cb_pending(timer))
-		hrtimer_remove_cb_pending(timer);
-	else {
+	if (timer->state & HRTIMER_STATE_ENQUEUED) {
 		/*
 		 * Remove the timer from the rbtree and replace the
 		 * first entry pointer if necessary.
@@ -953,7 +894,7 @@ hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_n
 {
 	struct hrtimer_clock_base *base, *new_base;
 	unsigned long flags;
-	int ret, raise;
+	int ret, leftmost;
 
 	base = lock_hrtimer_base(timer, &flags);
 
@@ -981,33 +922,19 @@ hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_n
 
 	timer_stats_hrtimer_set_start_info(timer);
 
+	leftmost = enqueue_hrtimer(timer, new_base);
+
 	/*
 	 * Only allow reprogramming if the new base is on this CPU.
 	 * (it might still be on another CPU if the timer was pending)
+	 *
+	 * XXX send_remote_softirq() ?
 	 */
-	enqueue_hrtimer(timer, new_base,
-			new_base->cpu_base == &__get_cpu_var(hrtimer_bases));
-
-	/*
-	 * The timer may be expired and moved to the cb_pending
-	 * list. We can not raise the softirq with base lock held due
-	 * to a possible deadlock with runqueue lock.
-	 */
-	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();
+	if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
+		hrtimer_enqueue_reprogram(timer, new_base);
 
 	unlock_hrtimer_base(timer, &flags);
 
-	if (raise)
-		hrtimer_raise_softirq();
-	preempt_enable();
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
@@ -1192,75 +1119,6 @@ int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp)
 }
 EXPORT_SYMBOL_GPL(hrtimer_get_res);
 
-static void run_hrtimer_pending(struct hrtimer_cpu_base *cpu_base)
-{
-	spin_lock_irq(&cpu_base->lock);
-
-	while (!list_empty(&cpu_base->cb_pending)) {
-		enum hrtimer_restart (*fn)(struct hrtimer *);
-		struct hrtimer *timer;
-		int restart;
-		int emulate_hardirq_ctx = 0;
-
-		timer = list_entry(cpu_base->cb_pending.next,
-				   struct hrtimer, cb_entry);
-
-		debug_hrtimer_deactivate(timer);
-		timer_stats_account_hrtimer(timer);
-
-		fn = timer->function;
-		/*
-		 * A timer might have been added to the cb_pending list
-		 * when it was migrated during a cpu-offline operation.
-		 * Emulate hardirq context for such timers.
-		 */
-		if (timer->cb_mode == HRTIMER_CB_IRQSAFE_PERCPU ||
-		    timer->cb_mode == HRTIMER_CB_IRQSAFE_UNLOCKED)
-			emulate_hardirq_ctx = 1;
-
-		__remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
-		spin_unlock_irq(&cpu_base->lock);
-
-		if (unlikely(emulate_hardirq_ctx)) {
-			local_irq_disable();
-			restart = fn(timer);
-			local_irq_enable();
-		} else
-			restart = fn(timer);
-
-		spin_lock_irq(&cpu_base->lock);
-
-		timer->state &= ~HRTIMER_STATE_CALLBACK;
-		if (restart == HRTIMER_RESTART) {
-			BUG_ON(hrtimer_active(timer));
-			/*
-			 * Enqueue the timer, allow reprogramming of the event
-			 * device
-			 */
-			enqueue_hrtimer(timer, timer->base, 1);
-		} else if (hrtimer_active(timer)) {
-			/*
-			 * If the timer was rearmed on another CPU, reprogram
-			 * the event device.
-			 */
-			struct hrtimer_clock_base *base = timer->base;
-
-			if (base->first == &timer->node &&
-			    hrtimer_reprogram(timer, base)) {
-				/*
-				 * Timer is expired. Thus move it from tree to
-				 * pending list again.
-				 */
-				__remove_hrtimer(timer, base,
-						 HRTIMER_STATE_PENDING, 0);
-				list_add_tail(&timer->cb_entry,
-					      &base->cpu_base->cb_pending);
-			}
-		}
-	}
-	spin_unlock_irq(&cpu_base->lock);
-}
-
 static void __run_hrtimer(struct hrtimer *timer)
 {
 	struct hrtimer_clock_base *base = timer->base;
@@ -1268,34 +1126,30 @@ static void __run_hrtimer(struct hrtimer *timer)
 	enum hrtimer_restart (*fn)(struct hrtimer *);
 	int restart;
 
+	WARN_ON(!irqs_disabled());
+
 	debug_hrtimer_deactivate(timer);
 	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
 	timer_stats_account_hrtimer(timer);
-
 	fn = timer->function;
-	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.
-		 *
-		 * These timers are required to deal with enqueue expiry
-		 * themselves and are not allowed to migrate.
-		 */
-		spin_unlock(&cpu_base->lock);
-		restart = fn(timer);
-		spin_lock(&cpu_base->lock);
-	} else
-		restart = fn(timer);
 
 	/*
-	 * Note: We clear the CALLBACK bit after enqueue_hrtimer to avoid
-	 * reprogramming of the event hardware. This happens at the end of this
-	 * function anyway.
+	 * Because we run timers from hardirq context, there is no chance
+	 * they get migrated to another cpu, therefore its safe to unlock
+	 * the timer base.
+	 */
+	spin_unlock(&cpu_base->lock);
+	restart = fn(timer);
+	spin_lock(&cpu_base->lock);
+
+	/*
+	 * Note: We clear the CALLBACK bit after enqueue_hrtimer and
+	 * we do not reprogramm the event hardware. Happens either in
+	 * hrtimer_start_range_ns() or in hrtimer_interrupt()
 	 */
 	if (restart != HRTIMER_NORESTART) {
 		BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
-		enqueue_hrtimer(timer, base, 0);
+		enqueue_hrtimer(timer, base);
 	}
 	timer->state &= ~HRTIMER_STATE_CALLBACK;
 }
@@ -1311,7 +1165,7 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
 	struct hrtimer_clock_base *base;
 	ktime_t expires_next, now;
-	int i, raise = 0;
+	int i;
 
 	BUG_ON(!cpu_base->hres_active);
 	cpu_base->nr_events++;
@@ -1360,16 +1214,6 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 				break;
 			}
 
-			/* Move softirq callbacks to the pending list */
-			if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
-				__remove_hrtimer(timer, base,
-						 HRTIMER_STATE_PENDING, 0);
-				list_add_tail(&timer->cb_entry,
-					      &base->cpu_base->cb_pending);
-				raise = 1;
-				continue;
-			}
-
 			__run_hrtimer(timer);
 		}
 		spin_unlock(&cpu_base->lock);
@@ -1383,10 +1227,22 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 		if (tick_program_event(expires_next, 0))
 			goto retry;
 	}
+}
+
+/*
+ * local version of hrtimer_peek_ahead_timers() called with interrupts
+ * disabled.
+ */
+static void __hrtimer_peek_ahead_timers(void)
+{
+	struct tick_device *td;
+
+	if (!hrtimer_hres_active())
+		return;
 
-	/* Raise softirq ? */
-	if (raise)
-		raise_softirq(HRTIMER_SOFTIRQ);
+	td = &__get_cpu_var(tick_cpu_device);
+	if (td && td->evtdev)
+		hrtimer_interrupt(td->evtdev);
 }
 
 /**
@@ -1400,25 +1256,23 @@ void hrtimer_interrupt(struct clock_event_device *dev)
  */
 void hrtimer_peek_ahead_timers(void)
 {
-	struct tick_device *td;
 	unsigned long flags;
 
-	if (!hrtimer_hres_active())
-		return;
-
 	local_irq_save(flags);
-	td = &__get_cpu_var(tick_cpu_device);
-	if (td && td->evtdev)
-		hrtimer_interrupt(td->evtdev);
+	__hrtimer_peek_ahead_timers();
 	local_irq_restore(flags);
 }
 
 static void run_hrtimer_softirq(struct softirq_action *h)
 {
-	run_hrtimer_pending(&__get_cpu_var(hrtimer_bases));
+	hrtimer_peek_ahead_timers();
 }
 
-#endif	/* CONFIG_HIGH_RES_TIMERS */
+#else /* CONFIG_HIGH_RES_TIMERS */
+
+static inline void __hrtimer_peek_ahead_timers(void) { }
+
+#endif	/* !CONFIG_HIGH_RES_TIMERS */
 
 /*
  * Called from timer softirq every jiffy, expire hrtimers:
@@ -1429,8 +1283,6 @@ static void run_hrtimer_softirq(struct softirq_action *h)
  */
 void hrtimer_run_pending(void)
 {
-	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
-
 	if (hrtimer_hres_active())
 		return;
 
@@ -1444,8 +1296,6 @@ void hrtimer_run_pending(void)
 	 */
 	if (tick_check_oneshot_change(!hrtimer_is_hres_enabled()))
 		hrtimer_switch_to_hres();
-
-	run_hrtimer_pending(cpu_base);
 }
 
 /*
@@ -1482,14 +1332,6 @@ void hrtimer_run_queues(void)
 					hrtimer_get_expires_tv64(timer))
 				break;
 
-			if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
-				__remove_hrtimer(timer, base,
-					HRTIMER_STATE_PENDING, 0);
-				list_add_tail(&timer->cb_entry,
-					&base->cpu_base->cb_pending);
-				continue;
-			}
-
 			__run_hrtimer(timer);
 		}
 		spin_unlock(&cpu_base->lock);
@@ -1516,9 +1358,6 @@ 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_UNLOCKED;
-#endif
 }
 
 static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode)
@@ -1655,18 +1494,16 @@ static void __cpuinit init_hrtimers_cpu(int cpu)
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
 		cpu_base->clock_base[i].cpu_base = cpu_base;
 
-	INIT_LIST_HEAD(&cpu_base->cb_pending);
 	hrtimer_init_hres(cpu_base);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
 
-static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
-				struct hrtimer_clock_base *new_base, int dcpu)
+static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+				struct hrtimer_clock_base *new_base)
 {
 	struct hrtimer *timer;
 	struct rb_node *node;
-	int raise = 0;
 
 	while ((node = rb_first(&old_base->active))) {
 		timer = rb_entry(node, struct hrtimer, node);
@@ -1674,18 +1511,6 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
 		debug_hrtimer_deactivate(timer);
 
 		/*
-		 * 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
@@ -1693,112 +1518,73 @@ static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
 		__remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0);
 		timer->base = new_base;
 		/*
-		 * Enqueue the timer. Allow reprogramming of the event device
+		 * Enqueue the timers on the new cpu. This does not
+		 * reprogram the event device in case the timer
+		 * expires before the earliest on this CPU, but we run
+		 * hrtimer_interrupt after we migrated everything to
+		 * sort out already expired timers and reprogram the
+		 * event device.
 		 */
-		enqueue_hrtimer(timer, new_base, 1);
+		enqueue_hrtimer(timer, new_base);
 
-#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)
+static void migrate_hrtimers(int scpu)
 {
 	struct hrtimer_cpu_base *old_base, *new_base;
-	int i, raise = 0;
+	int i;
 
-	BUG_ON(cpu_online(cpu));
-	old_base = &per_cpu(hrtimer_bases, cpu);
-	new_base = &get_cpu_var(hrtimer_bases);
+	BUG_ON(cpu_online(scpu));
+	tick_cancel_sched_timer(scpu);
 
-	tick_cancel_sched_timer(cpu);
+	local_irq_disable();
+	old_base = &per_cpu(hrtimer_bases, scpu);
+	new_base = &__get_cpu_var(hrtimer_bases);
 	/*
 	 * 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(&new_base->lock);
 	spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
-		if (migrate_hrtimer_list(&old_base->clock_base[i],
-					 &new_base->clock_base[i], cpu))
-			raise = 1;
+		migrate_hrtimer_list(&old_base->clock_base[i],
+				     &new_base->clock_base[i]);
 	}
 
-	if (migrate_hrtimer_pending(old_base, new_base))
-		raise = 1;
-
 	spin_unlock(&old_base->lock);
-	spin_unlock_irq(&new_base->lock);
-	put_cpu_var(hrtimer_bases);
+	spin_unlock(&new_base->lock);
 
-	if (raise)
-		hrtimer_raise_softirq();
+	/* Check, if we got expired work to do */
+	__hrtimer_peek_ahead_timers();
+	local_irq_enable();
 }
+
 #endif /* CONFIG_HOTPLUG_CPU */
 
 static int __cpuinit hrtimer_cpu_notify(struct notifier_block *self,
 					unsigned long action, void *hcpu)
 {
-	unsigned int cpu = (long)hcpu;
+	int scpu = (long)hcpu;
 
 	switch (action) {
 
 	case CPU_UP_PREPARE:
 	case CPU_UP_PREPARE_FROZEN:
-		init_hrtimers_cpu(cpu);
+		init_hrtimers_cpu(scpu);
 		break;
 
 #ifdef CONFIG_HOTPLUG_CPU
 	case CPU_DEAD:
 	case CPU_DEAD_FROZEN:
-		clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &cpu);
-		migrate_hrtimers(cpu);
+	{
+		clockevents_notify(CLOCK_EVT_NOTIFY_CPU_DEAD, &scpu);
+		migrate_hrtimers(scpu);
 		break;
+	}
 #endif
 
 	default: