linux-kernel - [PATCH 3/7] sched/fair: Correct unit of load_above

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Message-Id: <1461958364-675-4-git-send-email-dietmar.eggemann@arm.com>
Date:	Fri, 29 Apr 2016 20:32:40 +0100
From:	Dietmar Eggemann <dietmar.eggemann@....com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	linux-kernel@...r.kernel.org,
	Morten Rasmussen <morten.rasmussen@....com>
Subject: [PATCH 3/7] sched/fair: Correct unit of load_above_capacity

From: Morten Rasmussen <morten.rasmussen@....com>

In calculate_imbalance() load_above_capacity currently has the unit
[load] while it is used as being [load/capacity]. Not only is it wrong it
also makes it unlikely that load_above_capacity is ever used as the
subsequent code picks the smaller of load_above_capacity and the avg_load
difference between the local and the busiest sched_groups.

This patch ensures that load_above_capacity has the right unit
[load/capacity].

Signed-off-by: Morten Rasmussen <morten.rasmussen@....com>
---
 kernel/sched/fair.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index bc19fee94f39..c066574cff04 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7016,9 +7016,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
 	    local->group_type   == group_overloaded) {
 		load_above_capacity = busiest->sum_nr_running *
 					SCHED_LOAD_SCALE;
-		if (load_above_capacity > busiest->group_capacity)
+		if (load_above_capacity > busiest->group_capacity) {
 			load_above_capacity -= busiest->group_capacity;
-		else
+			load_above_capacity *= SCHED_LOAD_SCALE;
+			load_above_capacity /= busiest->group_capacity;
+		} else
 			load_above_capacity = ~0UL;
 	}
 
-- 
1.9.1