---

yaml
---
r: 96040
b: refs/heads/master
c: b328ca1
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 104f64549c961a797ff5f7c59946a7caa335c5b0
+refs/heads/master: b328ca182f01c2a04b85e0ee8a410720b104fbcc

trunk/kernel/sched.c

@@ -1191,6 +1191,7 @@ static inline void resched_rq(struct rq *rq)
 enum {
 	HRTICK_SET,		/* re-programm hrtick_timer */
 	HRTICK_RESET,		/* not a new slice */
+	HRTICK_BLOCK,		/* stop hrtick operations */
 };
 
 /*
@@ -1202,6 +1203,8 @@ static inline int hrtick_enabled(struct rq *rq)
 {
 	if (!sched_feat(HRTICK))
 		return 0;
+	if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags)))
+		return 0;
 	return hrtimer_is_hres_active(&rq->hrtick_timer);
 }
 
@@ -1284,7 +1287,63 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
 	return HRTIMER_NORESTART;
 }
 
-static inline void init_rq_hrtick(struct rq *rq)
+static void hotplug_hrtick_disable(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	spin_lock_irqsave(&rq->lock, flags);
+	rq->hrtick_flags = 0;
+	__set_bit(HRTICK_BLOCK, &rq->hrtick_flags);
+	spin_unlock_irqrestore(&rq->lock, flags);
+
+	hrtick_clear(rq);
+}
+
+static void hotplug_hrtick_enable(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	spin_lock_irqsave(&rq->lock, flags);
+	__clear_bit(HRTICK_BLOCK, &rq->hrtick_flags);
+	spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static int
+hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+	int cpu = (int)(long)hcpu;
+
+	switch (action) {
+	case CPU_UP_CANCELED:
+	case CPU_UP_CANCELED_FROZEN:
+	case CPU_DOWN_PREPARE:
+	case CPU_DOWN_PREPARE_FROZEN:
+	case CPU_DEAD:
+	case CPU_DEAD_FROZEN:
+		hotplug_hrtick_disable(cpu);
+		return NOTIFY_OK;
+
+	case CPU_UP_PREPARE:
+	case CPU_UP_PREPARE_FROZEN:
+	case CPU_DOWN_FAILED:
+	case CPU_DOWN_FAILED_FROZEN:
+	case CPU_ONLINE:
+	case CPU_ONLINE_FROZEN:
+		hotplug_hrtick_enable(cpu);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static void init_hrtick(void)
+{
+	hotcpu_notifier(hotplug_hrtick, 0);
+}
+
+static void init_rq_hrtick(struct rq *rq)
 {
 	rq->hrtick_flags = 0;
 	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
@@ -1321,6 +1380,10 @@ static inline void init_rq_hrtick(struct rq *rq)
 void hrtick_resched(void)
 {
 }
+
+static inline void init_hrtick(void)
+{
+}
 #endif
 
 /*
@@ -7943,6 +8006,7 @@ void __init sched_init_smp(void)
 	put_online_cpus();
 	/* XXX: Theoretical race here - CPU may be hotplugged now */
 	hotcpu_notifier(update_sched_domains, 0);
+	init_hrtick();
 
 	/* Move init over to a non-isolated CPU */
 	if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)