From 1662867a9b2574bfdb9d4e97186aa131218d7210 Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@redhat.com>
Date: Sun, 8 Jun 2014 16:55:57 -0400
Subject: [PATCH] numa,sched: fix load_to_imbalanced logic inversion
This function is supposed to return true if the new load imbalance is
worse than the old one. It didn't. I can only hope brown paper bags
are in style.
Now things converge much better on both the 4 node and 8 node systems.
I am not sure why this did not seem to impact specjbb performance on the
4 node system, which is the system I have full-time access to.
This bug was introduced recently, with commit e63da03639cc ("sched/numa:
Allow task switch if load imbalance improves")
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 17de1956ddad6..9855e87d671a5 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1120,7 +1120,7 @@ static bool load_too_imbalanced(long orig_src_load, long orig_dst_load,
old_imb = orig_dst_load * 100 - orig_src_load * env->imbalance_pct;
/* Would this change make things worse? */
- return (old_imb > imb);
+ return (imb > old_imb);
}
/*
--
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