---

yaml
---
r: 205420
b: refs/heads/master
c: 83cd4fe
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: fdf3e95d3916f18bf8703fb065499fdbc4dfe34c
+refs/heads/master: 83cd4fe27ad8446619b2e030b171b858501de87d

trunk/include/linux/sched.h

@@ -271,14 +271,11 @@ extern int runqueue_is_locked(int cpu);
 
 extern cpumask_var_t nohz_cpu_mask;
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
-extern int select_nohz_load_balancer(int cpu);
-extern int get_nohz_load_balancer(void);
+extern void select_nohz_load_balancer(int stop_tick);
+extern int get_nohz_timer_target(void);
 extern int nohz_ratelimit(int cpu);
 #else
-static inline int select_nohz_load_balancer(int cpu)
-{
-	return 0;
-}
+static inline void select_nohz_load_balancer(int stop_tick) { }
 
 static inline int nohz_ratelimit(int cpu)
 {

trunk/kernel/hrtimer.c

@@ -144,12 +144,8 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
 static int hrtimer_get_target(int this_cpu, int pinned)
 {
 #ifdef CONFIG_NO_HZ
-	if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu)) {
-		int preferred_cpu = get_nohz_load_balancer();
-
-		if (preferred_cpu >= 0)
-			return preferred_cpu;
-	}
+	if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
+		return get_nohz_timer_target();
 #endif
 	return this_cpu;
 }

trunk/kernel/sched.c

@@ -460,7 +460,7 @@ struct rq {
 	unsigned long last_load_update_tick;
 #ifdef CONFIG_NO_HZ
 	u64 nohz_stamp;
-	unsigned char in_nohz_recently;
+	unsigned char nohz_balance_kick;
 #endif
 	unsigned int skip_clock_update;
 
@@ -1194,6 +1194,27 @@ static void resched_cpu(int cpu)
 }
 
 #ifdef CONFIG_NO_HZ
+/*
+ * In the semi idle case, use the nearest busy cpu for migrating timers
+ * from an idle cpu.  This is good for power-savings.
+ *
+ * We don't do similar optimization for completely idle system, as
+ * selecting an idle cpu will add more delays to the timers than intended
+ * (as that cpu's timer base may not be uptodate wrt jiffies etc).
+ */
+int get_nohz_timer_target(void)
+{
+	int cpu = smp_processor_id();
+	int i;
+	struct sched_domain *sd;
+
+	for_each_domain(cpu, sd) {
+		for_each_cpu(i, sched_domain_span(sd))
+			if (!idle_cpu(i))
+				return i;
+	}
+	return cpu;
+}
 /*
  * When add_timer_on() enqueues a timer into the timer wheel of an
  * idle CPU then this timer might expire before the next timer event
@@ -7791,6 +7812,10 @@ void __init sched_init(void)
 		rq->idle_stamp = 0;
 		rq->avg_idle = 2*sysctl_sched_migration_cost;
 		rq_attach_root(rq, &def_root_domain);
+#ifdef CONFIG_NO_HZ
+		rq->nohz_balance_kick = 0;
+		init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb, i));
+#endif
 #endif
 		init_rq_hrtick(rq);
 		atomic_set(&rq->nr_iowait, 0);
@@ -7835,8 +7860,11 @@ void __init sched_init(void)
 	zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
 #ifdef CONFIG_SMP
 #ifdef CONFIG_NO_HZ
-	zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
-	alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
+	zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
+	alloc_cpumask_var(&nohz.grp_idle_mask, GFP_NOWAIT);
+	atomic_set(&nohz.load_balancer, nr_cpu_ids);
+	atomic_set(&nohz.first_pick_cpu, nr_cpu_ids);
+	atomic_set(&nohz.second_pick_cpu, nr_cpu_ids);
 #endif
 	/* May be allocated at isolcpus cmdline parse time */
 	if (cpu_isolated_map == NULL)