linux-kernel - [RFC PATCH 11/12 v2] Intercept periodic load balancing

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Date:	Mon, 12 May 2014 02:17:00 +0800
From:	Yuyang Du <yuyang.du@...el.com>
To:	mingo@...hat.com, peterz@...radead.org, rafael.j.wysocki@...el.com,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Cc:	arjan.van.de.ven@...el.com, len.brown@...el.com,
	alan.cox@...el.com, mark.gross@...el.com, morten.rasmussen@....com,
	vincent.guittot@...aro.org, rajeev.d.muralidhar@...el.com,
	vishwesh.m.rudramuni@...el.com, nicole.chalhoub@...el.com,
	ajaya.durg@...el.com, harinarayanan.seshadri@...el.com,
	jacob.jun.pan@...ux.intel.com, fengguang.wu@...el.com,
	yuyang.du@...el.com
Subject: [RFC PATCH 11/12 v2] Intercept periodic load balancing

We intercept load balancing to contain the load and load balancing in
the consolidated CPUs according to our consolidating mechanism.

In periodic load balancing, we do two things:

1) Skip pulling task to the non-consolidated CPUs.

2) In addition, for consolidated Idle CPU, we aggressively pull tasks from
non-consolidated CPUs.

Signed-off-by: Yuyang Du <yuyang.du@...el.com>
---
 kernel/sched/fair.c |   33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9bb1304..1c7a3d7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7260,6 +7260,36 @@ static void run_rebalance_domains(struct softirq_action *h)
 	enum cpu_idle_type idle = this_rq->idle_balance ?
 						CPU_IDLE : CPU_NOT_IDLE;
 
+#ifdef CONFIG_WORKLOAD_CONSOLIDATION
+	struct cpumask *nonshielded = __get_cpu_var(local_cpu_mask);
+	int this_cpu = cpu_of(this_rq);
+
+	/*
+	 * if we encounter shielded cpus here, don't do balance on them
+	 */
+	cpumask_copy(nonshielded, cpu_active_mask);
+
+	rcu_read_lock();
+	workload_consolidation_nonshielded_mask(this_cpu, nonshielded);
+	rcu_read_unlock();
+
+	/*
+	 * aggressively unload the shielded cpus to unshielded cpus
+	 */
+	workload_consolidation_unload(nonshielded);
+
+	if (cpumask_test_cpu(this_cpu, nonshielded)) {
+		rebalance_domains(this_rq, idle);
+
+		/*
+		 * If this cpu has a pending nohz_balance_kick, then do the
+		 * balancing on behalf of the other idle cpus whose ticks are
+		 * stopped.
+		 */
+		cpumask_and(nonshielded, nonshielded, nohz.idle_cpus_mask);
+		nohz_idle_balance(this_rq, idle, nonshielded);
+	}
+#else
 	rebalance_domains(this_rq, idle);
 
 	/*
@@ -7267,7 +7297,8 @@ static void run_rebalance_domains(struct softirq_action *h)
 	 * balancing on behalf of the other idle cpus whose ticks are
 	 * stopped.
 	 */
-	nohz_idle_balance(this_rq, idle);
+	nohz_idle_balance(this_rq, idle, nohz.idle_cpus_mask);
+#endif
 }
 
 /*
-- 
1.7.9.5

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