To: Ingo Oeser <ioe-lkml@rameria.de>
Cc: Russ Anderson <rja@sgi.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, x86@kernel.org
Subject: Re: [PATCH 1/2] Avoid putting a bad page back on the LRU
From: Andi Kleen <andi@firstfloor.org>
References: <20090408001133.GB27170@sgi.com>
	<200904080543.16454.ioe-lkml@rameria.de>
Date: Wed, 08 Apr 2009 08:46:41 +0200
In-Reply-To: <200904080543.16454.ioe-lkml@rameria.de> (Ingo Oeser's message of "Wed, 8 Apr 2009 05:43:15 +0200")
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Ingo Oeser <ioe-lkml@rameria.de> writes:
>
> Clearing the flag doesn't change the fact, that this page is representing 
> permanently bad RAM.

Yes, you cannot ever clear a Poison flag, at least not without a special
hardware mechanism that clears the hardware poison too (but that has
other issues in Linux too). Otherwise you would die later.

> What about removing it from the LRU and adding it to a bad RAM list in every case?

That is what memory_failure() already should be doing. Except there's no list
currently.

> After hot swapping the physical RAM banks it could be moved back, not before.

Linux doesn't really support that. That is at least not when it's OS visible.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.
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