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

Ingo Molnar
2009-03-28T12:08:46Z

* 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