From: Peter Zijlstra Date: Wed, 20 Jul 2011 16:42:57 +0000 (+0200) Subject: sched: Avoid creating superfluous NUMA domains on non-NUMA systems X-Git-Tag: v3.0~8^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d110235d2c331c4f79e0879f51104be79e17a469;p=platform%2Fkernel%2Flinux-stable.git 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 Signed-off-by: Peter Zijlstra Cc: Anton Blanchard 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 --- diff --git a/kernel/sched.c b/kernel/sched.c index 921adf6..14168c4 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)