Re: [PATCH -tip 1/3] x86, mce: Add mce_threshold option for intel cmci

[Ingo Molnar <mingo@elte.hu>]

* Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> wrote:

> This patch adds a kernel parameter "mce_threshold=n" to enable us
> to change the default threshold for CMCI(Corrected Machine Check
> Interrupt) that recent Intel processor supports.
> 
> And it also supports CMCI disabling by setting mce_threshold=0.
> It would be useful if your hardware does something wrong and/or
> if polling by timer is preferred than the threshold interrupt.
> 
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> ---
>  Documentation/kernel-parameters.txt       |    5 +++
>  arch/x86/include/asm/msr-index.h          |    1 +
>  arch/x86/kernel/cpu/mcheck/mce_intel_64.c |   56 +++++++++++++++++++++++++++--
>  3 files changed, 59 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 1d8af36..7a0d117 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1267,6 +1267,11 @@ and is between 256 and 4096 characters. It is defined in the file
>  
>  	mce=option	[X86-64] See Documentation/x86/x86_64/boot-options.txt
>  
> +	mce_threshold=	[X86-64,intel] Default CMCI threshold
> +			Should be unsigned integer. Setting 0 disables cmci.
> +			Format: <integer>
> +			Default: 1

Makes sense. CMCI is a new CPU feature so having boot controls to 
disable it is generally a good idea - while still having old-style 
MCE support in place.

Applied to tip:x86/mce2, thanks Hidetoshi!

	Ingo