linux-kernel - [PATCH 3/7] sched/fair: fix definitions of effective load

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Date:   Fri, 14 Jul 2017 13:21:00 +0000
From:   Josef Bacik <josef@...icpanda.com>
To:     mingo@...hat.com, peterz@...radead.org,
        linux-kernel@...r.kernel.org, umgwanakikbuti@...il.com,
        tj@...nel.org, kernel-team@...com
Cc:     Josef Bacik <jbacik@...com>
Subject: [PATCH 3/7] sched/fair: fix definitions of effective load

From: Josef Bacik <jbacik@...com>

It appears as though we've reversed the definitions of 'this_effective_load' and
'prev_effective_load'.  We seem to be using the wrong CPU capacity for both of
these parameters, and we want to add the imbalance percentage to the current CPU
to make sure we're meeting a high enough load imbalance threshold to justify
moving the task.

Signed-off-by: Josef Bacik <jbacik@...com>
---
 kernel/sched/fair.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5d4489e..d958634 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5679,11 +5679,11 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
 	 * Otherwise check if either cpus are near enough in load to allow this
 	 * task to be woken on this_cpu.
 	 */
-	this_eff_load = 100;
-	this_eff_load *= capacity_of(prev_cpu);
+	prev_eff_load = 100;
+	prev_eff_load *= capacity_of(prev_cpu);
 
-	prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
-	prev_eff_load *= capacity_of(this_cpu);
+	this_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
+	this_eff_load *= capacity_of(this_cpu);
 
 	if (this_load > 0) {
 		this_eff_load *= this_load +
-- 
2.9.3