Commit d110235d authored Jul 20, 2011 by Peter Zijlstra Committed by Ingo Molnar Jul 20, 2011

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>

parent e3589f6c

kernel/sched.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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)

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