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authorKen Chen <kenchen@google.com>2008-12-07 18:47:37 -0800
committerIngo Molnar <mingo@elte.hu>2008-12-08 13:52:44 +0100
commit5436499e6098759c2340f8b906ea52f993dc4efb (patch)
tree5af189c8d0d8bf5bc6261a427c371bd4d8ba7474
parent4d117c5c6b00254e51c61ff5b506ccaba21a5a03 (diff)
sched: fix sd_parent_degenerate on non-numa smp machine
Impact: optimize the sched domains tree some more The addition of SD_SERIALIZE flag added to SD_NODE_INIT prevented top level dummy numa sched_domain to be properly degenerated on non-numa smp machine. The reason is that in sd_parent_degenerate(), it found that the child and parent does not have comon sched_domain flags due to SD_SERIALIZE. However, for non-numa smp box, the top level is a dummy with a single sched_group. Filter out SD_SERIALIZE if it is on non-numa machine to properly degenerate top level node sched_domain. this will cut back some of the sd domain walk in the load balancer code. Signed-off-by: Ken Chen <kenchen@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 152828239ef..74498c840f9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6768,6 +6768,8 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
SD_BALANCE_EXEC |
SD_SHARE_CPUPOWER |
SD_SHARE_PKG_RESOURCES);
+ if (nr_node_ids == 1)
+ pflags &= ~SD_SERIALIZE;
}
if (~cflags & pflags)
return 0;