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Ingo Molnar authored
This patch fixes an interaction between the numa=fake=<domains> feature, the domain setup code and cpu_siblings_map[]. The bug leads to a bootup crash when using numa=fake=2 on a 2-way/4-way SMP+HT box. When SCHED_SMT is turned on the domains-setup code relies on siblings not spanning multiple domains (which makes perfect sense). But numa=fake=2 creates an assymetric 1101/0010 splitup between CPUs, which results in two siblings being on different nodes. The patch adds a check_siblings_map() function that checks the sibling maps and fixes them up if they violate this rule. (it also prints a warning in that case.) The patch also turns SCHED_DOMAIN_DEBUG back on - had this been enabled we'd have noticed this bug much earlier. From: Badari Pulavarty <pbadari@us.ibm.com> arch/x86_64/mm/numa.c: In function `numa_setup': arch/x86_64/mm/numa.c:332: error: `numa_fake' undeclared (first use in this function) arch/x86_64/mm/numa.c:332: error: (Each undeclared identifier is reported only once arch/x86_64/mm/numa.c:332: error: for each function it appears in.) Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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