[tip:sched/core] sched/fair: Implement update_blocked_averages() for CONFIG_FAIR_GROUP_SCHED=n

[tip-bot for Vincent Guittot <tipbot@zytor.com>]

Commit-ID:  6c1d47c0827304949e0eb9479f4d587f226fac8b
Gitweb:     http://git.kernel.org/tip/6c1d47c0827304949e0eb9479f4d587f226fac8b
Author:     Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Wed, 15 Jul 2015 08:04:38 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 3 Aug 2015 12:24:28 +0200

sched/fair: Implement update_blocked_averages() for CONFIG_FAIR_GROUP_SCHED=n

The load and the utilization of idle CPUs must be updated periodically in
order to decay the blocked part.

If CONFIG_FAIR_GROUP_SCHED is not set, the load and util of idle cpus
are not decayed and stay at the values set before becoming idle.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Yuyang Du <yuyang.du@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arjan@linux.intel.com
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: fengguang.wu@intel.com
Cc: len.brown@intel.com
Cc: morten.rasmussen@arm.com
Cc: pjt@google.com
Cc: rafael.j.wysocki@intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/1436918682-4971-4-git-send-email-yuyang.du@intel.com
[ Fixed up the SOB chain. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/fair.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 01ffa95..e4b80c6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5846,6 +5846,14 @@ static unsigned long task_h_load(struct task_struct *p)
 #else
 static inline void update_blocked_averages(int cpu)
 {
+	struct rq *rq = cpu_rq(cpu);
+	struct cfs_rq *cfs_rq = &rq->cfs;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rq->lock, flags);
+	update_rq_clock(rq);
+	update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq);
+	raw_spin_unlock_irqrestore(&rq->lock, flags);
 }
 
 static unsigned long task_h_load(struct task_struct *p)