linux-kernel - Re: [RESEND][PATCH -tip 2/3] x86, mce: Revert "add mce=nopoll option to disable timer polling"\

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Message-ID: <20090420100323.GW14687@one.firstfloor.org>
Date:	Mon, 20 Apr 2009 12:03:23 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>, Andi Kleen <ak@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [RESEND][PATCH -tip 2/3] x86, mce: Revert "add mce=nopoll option to disable timer polling"\

> 1) There is a agent checking/clearing corrected errors
>    (such as BIOS) other than OS.
> 
>    In this case, clearing MSRs by OS is not applicable.
>    So ignore_ce is better option here.

Yes, but how do you make sure the option is set when the agent is active?
I think relying on a kernel boot option here is quite fragile.
Also it's something the administrator shouldn't be involved in.

> 
> 2) There is no agent checking/clearing corrected errors.
>    User just want to suppress logs of corrected errors.
> 
>    In this case, dont_log_ce would be better option.
>    (Or adding filter to mcelog would be another solution)
> 
> I don't mind adding three options (no_cmci/ignore_ce/dont_log_ce)
> at once.  I'll rework 3/3 of this series to do so.
> 
> > Also for your use case really the better way would be to use
> > some way to let the firmware communicate that it doesn't want the OS
> > to log.
> 
> Yes.  However AFAIK there is no way to do it yet.

We can just define one. We had Linux specific extensions before.
Just needs a new bit somewhere. I think that would give a better
experience for your customers.

There might be something forthcomming that could be usable in fact.

> The original of this repost were posted about three weeks ago (Apr.2)...
> 
> I think your patches will go smoothly if my revert patches added before
> them.

The bug fixes should go in 2.6.30. After all that is what the rc stage
is for -- applying bug fixed.

> BTW, could you give me your Acked-by on this 2/3 too?

Not yet sorry.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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