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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-07-20 18:42:57 +0200
committerIngo Molnar <mingo@elte.hu>2011-07-20 18:54:33 +0200
commitd110235d2c331c4f79e0879f51104be79e17a469 (patch)
treed56bb05a1274f9e7c6a20467d2d04713c185e7ce
parente3589f6c81e4764d32a25d2a2a0afe54fa344f5c (diff)
downloadlinux-d110235d2c331c4f79e0879f51104be79e17a469.tar.bz2
sched: Avoid creating superfluous NUMA domains on non-NUMA systems
When creating sched_domains, stop when we've covered the entire target span instead of continuing to create domains, only to later find they're redundant and throw them away again. This avoids single node systems from touching funny NUMA sched_domain creation code and reduces the risks of the new SD_OVERLAP code. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Anton Blanchard <anton@samba.org> Cc: mahesh@linux.vnet.ibm.com Cc: benh@kernel.crashing.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins 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 921adf6f6fad..14168c49a154 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7436,6 +7436,8 @@ static int build_sched_domains(const struct cpumask *cpu_map,
sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
sd->flags |= SD_OVERLAP;
+ if (cpumask_equal(cpu_map, sched_domain_span(sd)))
+ break;
}
while (sd->child)