Commit-ID: 4596749339e06dc7a424fc08a15eded850ed78b7 Gitweb: https://git.kernel.org/tip/4596749339e06dc7a424fc08a15eded850ed78b7 Author: Samuel Neves <sneves@xxxxxxxxx> AuthorDate: Wed, 21 Feb 2018 20:50:36 +0000 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Fri, 23 Feb 2018 08:47:47 +0100 x86/topology: Update the 'cpu cores' field in /proc/cpuinfo correctly across CPU hotplug operations Without this fix, /proc/cpuinfo will display an incorrect amount of CPU cores, after bringing them offline and online again, as exemplified below: $ cat /proc/cpuinfo | grep cores cpu cores : 4 cpu cores : 8 cpu cores : 8 cpu cores : 20 cpu cores : 4 cpu cores : 3 cpu cores : 2 cpu cores : 2 This patch fixes this by always zeroing the booted_cores variable upon turning off a logical CPU. Tested-by: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx> Signed-off-by: Samuel Neves <sneves@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: jgross@xxxxxxxx Cc: luto@xxxxxxxxxx Cc: prarit@xxxxxxxxxx Cc: vkuznets@xxxxxxxxxx Link: http://lkml.kernel.org/r/20180221205036.5244-1-sneves@xxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/smpboot.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 9eee25d07586..ff99e2b6fc54 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1437,6 +1437,7 @@ static void remove_siblinginfo(int cpu) cpumask_clear(topology_sibling_cpumask(cpu)); cpumask_clear(topology_core_cpumask(cpu)); c->cpu_core_id = 0; + c->booted_cores = 0; cpumask_clear_cpu(cpu, cpu_sibling_setup_mask); recompute_smt_state(); } -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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