linux-kernel - Re: [PATCH 1/2] Avoid putting a bad page back on the LRU

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Message-Id: <200904080543.16454.ioe-lkml@rameria.de>
Date:	Wed, 8 Apr 2009 05:43:15 +0200
From:	Ingo Oeser <ioe-lkml@...eria.de>
To:	Russ Anderson <rja@....com>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org, x86@...nel.org,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH 1/2] Avoid putting a bad page back on the LRU

Hi Russ,

On Wednesday 08 April 2009, Russ Anderson wrote:
> --- linux-next.orig/mm/migrate.c	2009-04-07 18:32:12.781949840 -0500
> +++ linux-next/mm/migrate.c	2009-04-07 18:34:19.169736260 -0500
> @@ -693,6 +696,26 @@ unlock:
>   		 * restored.
>   		 */
>   		list_del(&page->lru);
> +#ifdef CONFIG_MEMORY_FAILURE
> +		if (PagePoison(page)) {
> +			if (rc == 0)
> +				/*
> +				 * A page with a memory error that has
> +				 * been migrated will not be moved to
> +				 * the LRU.
> +				 */
> +				goto move_newpage;
> +			else
> +				/*
> +				 * The page failed to migrate and will not
> +				 * be added to the bad page list.  Clearing
> +				 * the error bit will allow another attempt
> +				 * to migrate if it gets another correctable
> +				 * error.
> +				 */
> +				ClearPagePoison(page);

Clearing the flag doesn't change the fact, that this page is representing 
permanently bad RAM.

What about removing it from the LRU and adding it to a bad RAM list in every case?
After hot swapping the physical RAM banks it could be moved back, not before.


Best Regards

Ingo Oeser
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