Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756093AbYCKUBq (ORCPT ); Tue, 11 Mar 2008 16:01:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752793AbYCKUBj (ORCPT ); Tue, 11 Mar 2008 16:01:39 -0400 Received: from mail.gmx.net ([213.165.64.20]:34939 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752765AbYCKUBi (ORCPT ); Tue, 11 Mar 2008 16:01:38 -0400 X-Authenticated: #7313500 X-Provags-ID: V01U2FsdGVkX1/XVvxwf6fXIrh7yXlhzX4sIOYOz2LbpUz61WeHQi 1sr+0Ji8N9EPeb From: Jan-Simon =?utf-8?q?M=C3=B6ller?= To: Johannes Weiner Subject: Re: [PATCH 2.6.24] mm: BadRAM support for broken memory Date: Tue, 11 Mar 2008 21:00:59 +0100 User-Agent: KMail/1.9.9 Cc: Len Brown , "H. Peter Anvin" , Pavel Machek , Jiri Kosina , Ingo Molnar , devzero@web.de, linux-kernel@vger.kernel.org, rick@vanrein.org References: <182234194@web.de> <200803111849.53272.dl9pf@gmx.de> <873aqxqd1c.fsf@saeurebad.de> In-Reply-To: <873aqxqd1c.fsf@saeurebad.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200803112100.59851.dl9pf@gmx.de> X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3008 Lines: 103 V4 with checkpatch.pl done ... Start of Documentation for BadRAM/memmap - Reference: http://lkml.org/lkml/2008/3/2/42 Signed-off-by: Jan-Simon Moeller diff -up /dev/null bad-memory.txt --- /dev/null 2007-09-21 21:12:45.000000000 +0200 +++ bad-memory.txt 2008-03-11 18:44:45.101344820 +0100 @@ -0,0 +1,56 @@ +March 2008 +Jan-Simon Moeller, dl9pf@gmx.de + + +How to deal with bad memory e.g. reported by memtest86+ ? +######################################################### + +There are three possibilities I know of: + +1) Reinsert/swap the memory modules + +2) Buy new modules (best!) or try to exchange the memory + if you have spare-parts + +3) Use BadRAM or memmap + +This Howto is about number 3) . + + +BadRAM +###### +BadRAM is the 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 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.txt for details): +memmap=$
+ +With the numbers of the example above: +memmap=64K$0x18690000 + or +memmap=0x10000$0x18690000 + +TODO: Multiple areas to exclude using memmap ? + Add example of usage to memmap - evolved from thread about BadRAM inclusion. Signed-off-by: Jan-Simon Moeller diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 533e67f..f25da88 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1131,6 +1131,10 @@ and is between 256 and 4096 characters. It is defined in the file memmap=nn[KMG]$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=64K$0x18690000 + or + memmap=0x10000$0x18690000 meye.*= [HW] Set MotionEye Camera parameters See Documentation/video4linux/meye.txt. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/