From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 3327B900194 for ; Wed, 22 Jun 2011 16:30:45 -0400 (EDT) Message-ID: <4E0250F2.2010607@kpanic.de> Date: Wed, 22 Jun 2011 22:30:42 +0200 From: Stefan Assmann MIME-Version: 1.0 Subject: Re: [PATCH v2 0/3] support for broken memory modules (BadRAM) References: <1308741534-6846-1-git-send-email-sassmann@kpanic.de> <4E023142.1080605@zytor.com> In-Reply-To: <4E023142.1080605@zytor.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "H. Peter Anvin" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, tony.luck@intel.com, andi@firstfloor.org, mingo@elte.hu, rick@vanrein.org, rdunlap@xenotime.net On 22.06.2011 20:15, H. Peter Anvin wrote: > On 06/22/2011 04:18 AM, Stefan Assmann wrote: >> >> The idea is to allow the user to specify RAM addresses that shouldn't be >> touched by the OS, because they are broken in some way. Not all machines have >> hardware support for hwpoison, ECC RAM, etc, so here's a solution that allows to >> use bitmasks to mask address patterns with the new "badram" kernel command line >> parameter. >> Memtest86 has an option to generate these patterns since v2.3 so the only thing >> for the user to do should be: >> - run Memtest86 >> - note down the pattern >> - add badram= to the kernel command line >> > > We already support the equivalent functionality with > memmap=
$ for those with only a few ranges... this has > been supported for ages, literally. For those with a lot of ranges, > like Google, the command line is insufficient. Right, I think this has been discussed a while ago. So the advantages I see in this approach are. It allows to break down memory exclusion to the page level with a pattern of non-consecutive pages. So if every other page would be considered bad that's a bit tough to deal with using memmap. Secondly patterns can be easily generated by running Memtest86 and thus easily be fed to the kernel by command line. Making it much more feasible for the average user to take advantage of it. Stefan -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org