linux-kernel - Re: [RFC PATCH] x86/mce: Provide sysfs interface to show CMCI storm state

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Message-ID: <YLaaLws+4FEHOqQs@zn.tnic>
Date:   Tue, 1 Jun 2021 22:35:59 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Tony Luck <tony.luck@...el.com>
Cc:     Christopher BeSerra <beserra@...zon.com>, x86@...nel.org,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] x86/mce: Provide sysfs interface to show CMCI storm
 state

On Tue, Jun 01, 2021 at 01:05:05PM -0700, Tony Luck wrote:
> Scripts that process error logs can do better if they know whether
> Linux is executing in CMCI storm mode (only polling and reporting
> some errors instead of trying to report them all). While it is possible
> to parse the console log for:
> 
> 	CMCI storm detected: switching to poll mode
> 	CMCI storm subsided: switching to interrupt mode
> 
> messages, that is error prone.
> 
> Add a new file to sysfs to report the current storm count.
> 
> Reported-by: Christopher BeSerra <beserra@...zon.com>
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---
> 
> RFC questions:
> 1) Is there a better way to do this?

Probably.

But I'm unclear as to what this whole use case is. The very first
"Scripts that process error logs" already sounds like a bad idea - I'd
expect userspace consumers to open the trace_mce_record() and get the
MCE records from there. And in that case CMCI storm shouldn't matter...

-- 
Regards/Gruss,
    Boris.

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