linux-kernel - Re: [PATCH 2.6.24] mm: BadRAM support for broken memory

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Message-ID: <20080310225618.GA31624@elf.ucw.cz>
Date:	Mon, 10 Mar 2008 23:56:18 +0100
From:	Pavel Machek <pavel@....cz>
To:	Jan-Simon Möller <dl9pf@....de>
Cc:	"H. Peter Anvin" <hpa@...or.com>, Jiri Kosina <jkosina@...e.cz>,
	Ingo Molnar <mingo@...e.hu>, devzero@....de,
	linux-kernel@...r.kernel.org, rick@...rein.org
Subject: Re: [PATCH 2.6.24] mm: BadRAM support for broken memory

Hi!

> What about ...

Thanks for doing this.

> diff --git a/Documentation/kernel-parameters.txt 
> b/Documentation/kernel-parameters.txt
> index 533e67f..19343e1 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1131,6 +1131,10 @@ and is between 256 and 4096 characters. It is defined 
> in the file
>         memmap=nn[KMG]$ss[KMG]
>                         [KNL,ACPI] Mark specific memory as reserved.
>                         Region of memory to be used, from ss to ss+nn.
> +                       Example: Exclude memory from 0x18690000-0x1869ffff
> +                                memmap=0x18690000$64K
> +                                or
> +                                memmap=0x18690000$10000

missing 0x after $.


> diff --git a/Documentation/bad-memory.txt b/Documentation/bad-memory.txt
> new file mode 100644
> index 0000000..53e817d
> --- /dev/null
> +++ b/Documentation/bad-memory.txt
> @@ -0,0 +1,55 @@
> +March 2007
> +Jan-Simon Moeller, dl9pf@....de
> +
> +
> +How to deal with bad memory e.g. reported by memtest86+ ?
> +#########################################################
> +
> +There are three possibilities I know of:
> +
> +1) Buy new memory (best!)
> +
> +2) Try to exchange the memory if you have spare-parts
> +
> +3) Use BadRAM or memmap
> +
> +This Howto is about number 3) .
> +
> +
> +BadRAM
> +######
> +BadRAM is actively developed and available as kernel-patch
> +here:  http://rick.vanrein.org/linux/badram/
> +
> +It takes the patterns of memtest86+ as arguments to exclude the defective
> +areas of the memory.
> +
> +Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 
> and
> +         some others. All had 0x1869xxxx in common, so I chose a pattern of
> +         0x18690000,0xffff0000.
> +         This means exclusion of the area from 0x18690000 to 0x1869ffff
> +         (which is a block of 64k).
> +         My kernel-cmdline was:  badram=0x18690000,0xffff0000
> +
> +There are efforts to bring BadRAM into mainline in some way, possibly using
> +memmap internally (maybe for 2.6.26 ?).
> +Thread on lkml: http://lkml.org/lkml/2008/3/2/42
> +
> +For more details see the BadRAM documentation.
> +
> +
> +memmap
> +######
> +memmap is already in the kernel and usable as kernel-parameter at boot-time.
> +Its syntax is different and you may need to calculate the values by yourself!
> +
> +Syntax to exclude a memory area (see kernel-parameters for details):
> +memmap=<address>$<size>
> +
> +With the numbers of the example above:
> +memmap=0x18690000$64K
> + or
> +memmap=0x18690000$0x10000
> +
> +TODO: Multiple areas to exclude using memmap ?
> +
> 
> Signed-off-by: Jan-Simon Moeller <dl9pf@....de>

Actually, I'd include both..  I guess you should fix the 0x, the year,
and submit it to akpm (or trivial?).
								Pavel

-- 
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