[PATCH 1/8] sched: fix a find_busiest_group buglet
From: Peter Zijlstra
Date: Fri Oct 24 2008 - 05:58:56 EST
In one of the group load balancer patches:
commit 408ed066b11cf9ee4536573b4269ee3613bd735e
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
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@xxxxxxxxx>
---
kernel/sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -3343,7 +3343,7 @@ 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;
--
--
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