Messages in this thread Patch in this message | | | Date | Sat, 19 Mar 2016 02:31:29 -0700 | From | tip-bot for Thomas Gleixner <> | Subject | [tip:x86/urgent] x86/topology: Use total_cpus not nr_cpu_ids for logical packages |
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Commit-ID: 3e8db2246b434c6b18a6a9f09904038bddcf76c7 Gitweb: http://git.kernel.org/tip/3e8db2246b434c6b18a6a9f09904038bddcf76c7 Author: Thomas Gleixner <tglx@linutronix.de> AuthorDate: Fri, 18 Mar 2016 17:20:30 +0100 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Sat, 19 Mar 2016 10:26:40 +0100
x86/topology: Use total_cpus not nr_cpu_ids for logical packages
nr_cpu_ids can be limited on the command line via nr_cpus=. That can break the logical package management because it results in a smaller number of packages, but the cpus to online are occupying the full package space as the hyper threads are enumerated after the physical cores typically.
total_cpus is the real possible cpu space not limited by nr_cpus command line and gives us the proper number of packages.
Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Fixes: 1f12e32f4cd5 ("x86/topology: Create logical package id") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Xiong Zhou <jencce.kernel@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Andreas Herrmann <aherrmann@suse.com> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1603181254330.3978@nanos --- arch/x86/kernel/smpboot.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 81e6a43..b2c99f8 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -325,9 +325,14 @@ static void __init smp_init_package_map(void) * By not including this we'll sometimes over-estimate the number of * logical packages by the amount of !present siblings, but this is * still better than MAX_LOCAL_APIC. + * + * We use total_cpus not nr_cpu_ids because nr_cpu_ids can be limited + * on the command line leading to a similar issue as the HT disable + * problem because the hyperthreads are usually enumerated after the + * primary cores. */ ncpus = boot_cpu_data.x86_max_cores; - __max_logical_packages = DIV_ROUND_UP(nr_cpu_ids, ncpus); + __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus); /* * Possibly larger than what we need as the number of apic ids per
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