From d8c3892f8f95ee8c686ae4e24550627bca288c7b Mon Sep 17 00:00:00 2001
From: Suresh Siddha <suresh.b.siddha@intel.com>
Date: Thu, 1 Dec 2011 17:07:33 -0800
Subject: [PATCH] --- yaml --- r: 277387 b: refs/heads/master c:
 69e1e811dcc436a6b129dbef273ad9ec22d095ce h: refs/heads/master i:   277385:
 37383a384bbbdfd47971b7217e531a2011c68663   277383:
 8b680d31440f914ce670db10b5b98a6680a0d9e3 v: v3

---
 [refs]                         |  2 +-
 trunk/include/linux/sched.h    |  6 ++++++
 trunk/kernel/sched/core.c      |  1 +
 trunk/kernel/sched/fair.c      | 31 +++++++++++++++++++++++++++++++
 trunk/kernel/sched/sched.h     |  1 +
 trunk/kernel/time/tick-sched.c |  9 +++++++++
 6 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 79fd7e43c2b6..f932634c9e5d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1c792db7f7957e2e34b9a164f08200e36a25dfd0
+refs/heads/master: 69e1e811dcc436a6b129dbef273ad9ec22d095ce
diff --git a/trunk/include/linux/sched.h b/trunk/include/linux/sched.h
index 8db17b7622ec..295666cb5b86 100644
--- a/trunk/include/linux/sched.h
+++ b/trunk/include/linux/sched.h
@@ -273,9 +273,11 @@ extern int runqueue_is_locked(int cpu);
 
 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ)
 extern void select_nohz_load_balancer(int stop_tick);
+extern void set_cpu_sd_state_idle(void);
 extern int get_nohz_timer_target(void);
 #else
 static inline void select_nohz_load_balancer(int stop_tick) { }
+static inline void set_cpu_sd_state_idle(void);
 #endif
 
 /*
@@ -901,6 +903,10 @@ struct sched_group_power {
 	 * single CPU.
 	 */
 	unsigned int power, power_orig;
+	/*
+	 * Number of busy cpus in this group.
+	 */
+	atomic_t nr_busy_cpus;
 };
 
 struct sched_group {
diff --git a/trunk/kernel/sched/core.c b/trunk/kernel/sched/core.c
index 7f1da77b83f3..699ff1499a8a 100644
--- a/trunk/kernel/sched/core.c
+++ b/trunk/kernel/sched/core.c
@@ -6024,6 +6024,7 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd)
 		return;
 
 	update_group_power(sd, cpu);
+	atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight);
 }
 
 int __weak arch_sd_sibling_asym_packing(void)
diff --git a/trunk/kernel/sched/fair.c b/trunk/kernel/sched/fair.c
index 50c06b0e9fab..e050563e97a4 100644
--- a/trunk/kernel/sched/fair.c
+++ b/trunk/kernel/sched/fair.c
@@ -4901,6 +4901,36 @@ static void nohz_balancer_kick(int cpu)
 	return;
 }
 
+static inline void set_cpu_sd_state_busy(void)
+{
+	struct sched_domain *sd;
+	int cpu = smp_processor_id();
+
+	if (!test_bit(NOHZ_IDLE, nohz_flags(cpu)))
+		return;
+	clear_bit(NOHZ_IDLE, nohz_flags(cpu));
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd)
+		atomic_inc(&sd->groups->sgp->nr_busy_cpus);
+	rcu_read_unlock();
+}
+
+void set_cpu_sd_state_idle(void)
+{
+	struct sched_domain *sd;
+	int cpu = smp_processor_id();
+
+	if (test_bit(NOHZ_IDLE, nohz_flags(cpu)))
+		return;
+	set_bit(NOHZ_IDLE, nohz_flags(cpu));
+
+	rcu_read_lock();
+	for_each_domain(cpu, sd)
+		atomic_dec(&sd->groups->sgp->nr_busy_cpus);
+	rcu_read_unlock();
+}
+
 /*
  * This routine will try to nominate the ilb (idle load balancing)
  * owner among the cpus whose ticks are stopped. ilb owner will do the idle
@@ -5135,6 +5165,7 @@ static inline int nohz_kick_needed(struct rq *rq, int cpu)
 	* We may be recently in ticked or tickless idle mode. At the first
 	* busy tick after returning from idle, we will update the busy stats.
 	*/
+	set_cpu_sd_state_busy();
 	if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))))
 		clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
 
diff --git a/trunk/kernel/sched/sched.h b/trunk/kernel/sched/sched.h
index cf7d02662bc2..91810f0ee3af 100644
--- a/trunk/kernel/sched/sched.h
+++ b/trunk/kernel/sched/sched.h
@@ -1069,6 +1069,7 @@ extern void account_cfs_bandwidth_used(int enabled, int was_enabled);
 enum rq_nohz_flag_bits {
 	NOHZ_TICK_STOPPED,
 	NOHZ_BALANCE_KICK,
+	NOHZ_IDLE,
 };
 
 #define nohz_flags(cpu)	(&cpu_rq(cpu)->nohz_flags)
diff --git a/trunk/kernel/time/tick-sched.c b/trunk/kernel/time/tick-sched.c
index 40420644d0ba..31cc06163ed5 100644
--- a/trunk/kernel/time/tick-sched.c
+++ b/trunk/kernel/time/tick-sched.c
@@ -296,6 +296,15 @@ void tick_nohz_stop_sched_tick(int inidle)
 	cpu = smp_processor_id();
 	ts = &per_cpu(tick_cpu_sched, cpu);
 
+	/*
+ 	 * Update the idle state in the scheduler domain hierarchy
+ 	 * when tick_nohz_stop_sched_tick() is called from the idle loop.
+ 	 * State will be updated to busy during the first busy tick after
+ 	 * exiting idle.
+ 	 */
+	if (inidle)
+		set_cpu_sd_state_idle();
+
 	/*
 	 * Call to tick_nohz_start_idle stops the last_update_time from being
 	 * updated. Thus, it must not be called in the event we are called from