Messages in this thread Patch in this message | | | Date | Fri, 8 May 2015 06:29:27 -0700 | From | "tip-bot for Kirill A. Shutemov" <> | Subject | [tip:x86/build] x86/kconfig: Bump default NR_CPUS from 8 to 64 for 64-bit configuration |
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Commit-ID: c5c19941ad1bb18f010ae47f1db333c00b276d55 Gitweb: http://git.kernel.org/tip/c5c19941ad1bb18f010ae47f1db333c00b276d55 Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> AuthorDate: Fri, 8 May 2015 13:25:45 +0300 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Fri, 8 May 2015 12:58:56 +0200
x86/kconfig: Bump default NR_CPUS from 8 to 64 for 64-bit configuration
Default NR_CPUS==8 is not enough to cover high-end desktop configuration: Haswell-E has upto 16 threads.
Let's increase default NR_CPUS to 64 on 64-bit configuration. With this value CPU bitmask will still fit into one unsigned long.
Default for 32-bit configuration is still 8: it's unlikely anybody will run 32-bit kernels on modern hardware.
As an alternative we could bump NR_CPUS to 128 to cover all dual-processor servers with some margin.
For reference: Debian and Suse build their kernels with NR_CPUS==512, Fedora -- 1024.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431080745-19792-1-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/Kconfig | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 226d569..83cd1c7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -851,7 +851,8 @@ config NR_CPUS default "1" if !SMP default "8192" if MAXSMP default "32" if SMP && X86_BIGSMP - default "8" if SMP + default "8" if SMP && X86_32 + default "64" if SMP ---help--- This allows you to specify the maximum number of CPUs which this kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum
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