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: <49EC523C.80908@jp.fujitsu.com>
Date:	Mon, 20 Apr 2009 19:45:16 +0900
From:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	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"\

Andi Kleen wrote:
>> 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.

Chicken and egg?

If there is a agent, and if the administrator cannot deactivate the agent,
then use this option.  For example, there are no updated BIOS.

>>> 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.

You are right in part.
But even if I defined one, it doesn't work until it actually used by
someone.  In other words, for example, it will require update of BIOS.

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

Some standard interface will be appreciated.
Having linux specific thing is not happy for hardware vendors, I guess.

>> 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.

Maybe you overlooked that patches here are against -tip tree, don't you?
I'd like to fix -tip tree, that will be merged in next window, 2.6.31-rc1.

>> BTW, could you give me your Acked-by on this 2/3 too?
> 
> Not yet sorry.

You have acked on 3/3... So you mean "keep mce=nopoll option in -tip" ?


Thanks,
H.Seto  


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