Commit-ID: bb61ccc7dbcbc1ed4600bef5610d99ec91fd7032 Gitweb: http://git.kernel.org/tip/bb61ccc7dbcbc1ed4600bef5610d99ec91fd7032 Author: Josh Boyer <jwboyer@xxxxxxxxxx> AuthorDate: Tue, 5 Nov 2013 09:37:29 -0500 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Wed, 6 Nov 2013 08:16:28 +0100 x86/cpu: Allow higher NR_CPUS values The current range for SMP configs is 2 - 512 CPUs, or a full 4096 in the case of MAXSMP. There are machines that have 1024 CPUs in them today and configuring a kernel for that means you are forced to set MAXSMP. This adds additional unnecessary overhead. While that overhead might be considered tiny for large machines, it isn't necessarily so if you are building a kernel that runs across a wide variety of machines. To cover the range of more common machines today, we allow NR_CPUS to be up to 4096 when CPUMASK_OFFSTACK is enabled. Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx> Cc: prarit@xxxxxxxxxx Cc: Russ Anderson <rja@xxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20131105143728.GJ9944@xxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/Kconfig | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f67e839..f03e428 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -825,14 +825,16 @@ config MAXSMP config NR_CPUS int "Maximum number of CPUs" if SMP && !MAXSMP range 2 8 if SMP && X86_32 && !X86_BIGSMP - range 2 512 if SMP && !MAXSMP + range 2 512 if SMP && !MAXSMP && !CPUMASK_OFFSTACK + range 2 4096 if SMP && !MAXSMP && CPUMASK_OFFSTACK && X86_64 default "1" if !SMP default "4096" if MAXSMP default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000) default "8" if SMP ---help--- This allows you to specify the maximum number of CPUs which this - kernel will support. The maximum supported value is 512 and the + kernel will support. If CPUMASK_OFFSTACK is enabled, the maximum + supported value is 4096, otherwise the maximum value is 512. The minimum value which makes sense is 2. This is purely to save memory - each supported CPU adds -- 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