linux-kernel - [PATCH 11/14] sched: filter task pull request

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Message-Id: <1366910611-20048-12-git-send-email-vincent.guittot@linaro.org>
Date:	Thu, 25 Apr 2013 19:23:27 +0200
From:	Vincent Guittot <vincent.guittot@...aro.org>
To:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linaro-kernel@...ts.linaro.org, peterz@...radead.org,
	mingo@...nel.org, linux@....linux.org.uk, pjt@...gle.com,
	santosh.shilimkar@...com, Morten.Rasmussen@....com,
	chander.kashyap@...aro.org, cmetcalf@...era.com,
	tony.luck@...el.com, alex.shi@...el.com, preeti@...ux.vnet.ibm.com
Cc:	paulmck@...ux.vnet.ibm.com, tglx@...utronix.de,
	len.brown@...el.com, arjan@...ux.intel.com,
	amit.kucheria@...aro.org, corbet@....net, l.majewski@...sung.com,
	Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH 11/14] sched: filter task pull request

Only CPUs that participates to the packing effort can pull tasks on a busiest
group.

Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 kernel/sched/fair.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 28f8ea7..6f63fb9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3494,6 +3494,12 @@ static bool is_buddy_full(int cpu)
 	return (sum * 1024 >= period * 1000);
 }
 
+static bool is_my_buddy(int cpu, int buddy)
+{
+	int my_buddy = per_cpu(sd_pack_buddy, cpu);
+	return (my_buddy == -1) || (buddy == my_buddy);
+}
+
 static bool is_light_task(struct task_struct *p)
 {
 	/* A light task runs less than 20% in average */
@@ -4688,8 +4694,8 @@ static inline void update_sg_lb_stats(struct lb_env *env,
 
 		/* Bias balancing toward cpus of our domain */
 		if (local_group) {
-			if (idle_cpu(i) && !first_idle_cpu &&
-					cpumask_test_cpu(i, sched_group_mask(group))) {
+			if (is_my_buddy(i, i) && idle_cpu(i) && !first_idle_cpu
+			 && cpumask_test_cpu(i, sched_group_mask(group))) {
 				first_idle_cpu = 1;
 				balance_cpu = i;
 			}
@@ -4817,6 +4823,10 @@ static void update_plb_buddy(int cpu, int *balance, struct sd_lb_stats *sds,
 
 	/* Get my new buddy */
 	buddy = per_cpu(sd_pack_buddy, cpu);
+
+	/* This CPU doesn't act for agressive packing */
+	if (buddy != cpu)
+		sds->busiest = 0;
 }
 
 /**
-- 
1.7.9.5

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