From 01c8c57d668d94f1036d9ab11a22aa24ca16a35d Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 24 Oct 2008 11:06:12 +0200
Subject: [PATCH] sched: fix a find_busiest_group buglet
In one of the group load balancer patches:
commit 408ed066b11cf9ee4536573b4269ee3613bd735e
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri Jun 27 13:41:28 2008 +0200
Subject: sched: hierarchical load vs find_busiest_group
The following change:
- if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >=
+ if (max_load - this_load + 2*busiest_load_per_task >=
busiest_load_per_task * imbn) {
made the condition always true, because imbn is [1,2].
Therefore, remove the 2*, and give the it a fair chance.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 6625c3c4b10..12bc367d924 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3344,7 +3344,7 @@ small_imbalance:
} else
this_load_per_task = cpu_avg_load_per_task(this_cpu);
- if (max_load - this_load + 2*busiest_load_per_task >=
+ if (max_load - this_load + busiest_load_per_task >=
busiest_load_per_task * imbn) {
*imbalance = busiest_load_per_task;
return busiest;
--
2.41.3