From ceb1cbac8eda66cf0f889def226b4e82f8ff857b Mon Sep 17 00:00:00 2001 From: Kamalesh Babulal Date: Thu, 31 May 2012 13:07:38 +0530 Subject: [PATCH] sched/x86: Calculate booted cores after construction of sibling_mask Commit 316ad248307fb ("sched/x86: Rewrite set_cpu_sibling_map()") broke the booted_cores accounting. The problem is that the booted_cores accounting needs all the sibling links set up. So restore the second loop and add a comment as to why its needed. On qemu booted with -smp sockets=1,cores=2,threads=2; Before: $ grep cores /proc/cpuinfo cpu cores : 2 cpu cores : 1 cpu cores : 4 cpu cores : 3 With the patch: $ grep cores /proc/cpuinfo cpu cores : 2 cpu cores : 2 cpu cores : 2 cpu cores : 2 Reported-by: Prarit Bhargava Reported-by: Borislav Petkov Signed-off-by: Kamalesh Babulal Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120531073738.GH7511@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/smpboot.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index fd019d78b1f4..3fab55bea29b 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -382,6 +382,15 @@ void __cpuinit set_cpu_sibling_map(int cpu) if ((i == cpu) || (has_mc && match_llc(c, o))) link_mask(llc_shared, cpu, i); + } + + /* + * This needs a separate iteration over the cpus because we rely on all + * cpu_sibling_mask links to be set-up. + */ + for_each_cpu(i, cpu_sibling_setup_mask) { + o = &cpu_data(i); + if ((i == cpu) || (has_mc && match_mc(c, o))) { link_mask(core, cpu, i); -- 2.34.1