linux-kernel - Re: [PATCH -v3] x86, MCE: Drop the default decoding notifier

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Message-ID: <20110414151621.GI10080@aftab>
Date:	Thu, 14 Apr 2011 17:16:21 +0200
From:	Borislav Petkov <bp@...64.org>
To:	Prarit Bhargava <prarit@...hat.com>
Cc:	Borislav Petkov <bp@...64.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Russ Anderson <rja@....com>,
	"Luck, Tony" <tony.luck@...el.com>,
	"dzickus@...hat.com" <dzickus@...hat.com>,
	"mstowe@...hat.com" <mstowe@...hat.com>,
	"dnelson@...hat.com" <dnelson@...hat.com>,
	"rja@...ricas.sgi.com" <rja@...ricas.sgi.com>
Subject: Re: [PATCH -v3] x86, MCE: Drop the default decoding notifier

On Thu, Apr 14, 2011 at 11:04:43AM -0400, Prarit Bhargava wrote:
> 
> 
> On 04/14/2011 11:00 AM, Borislav Petkov wrote:
> > On Wed, Apr 13, 2011 at 01:37:05PM -0400, Borislav Petkov wrote:
> >   
> >> In the worst case, we will report 32 CEs before panicking. For that case
> >> we either do printk_once as Tony suggested or we ratelimit it. I'll
> >> update the patch.
> >>     
> > Ok, how about the following, I ratelimit the printk to the default of 10
> > messages per 5 seconds. I've also got the hardware MCE injection patches
> > ready and will do some testing with them.
> >   
> 
> See my previous email ;)  I think just putting in a printk_once after
> the CE call to print_mce() in mce_panic() might be better?  At least
> that way we get the --ascii message for *EVERY* UC which IMO would be
> nice...

Are you sure? printk_once() is, as its name says, a one-time thing and
it is implemented that way - a static bool counter which is once set and
that's it. I.e., the "--ascii" message will be printed only once for the
system's lifetime.

The ratelimit-ed thing dumps it a strict number of times. In the end,
I don't have a strong opinion on how many times we issue it - I'm fine
with it either way.

Maybe some other opinions. Tony?

-- 
Regards/Gruss,
Boris.

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