Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758799Ab1DYSVR (ORCPT ); Mon, 25 Apr 2011 14:21:17 -0400 Received: from exprod7og111.obsmtp.com ([64.18.2.175]:43168 "EHLO exprod7og111.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757722Ab1DYSVQ (ORCPT ); Mon, 25 Apr 2011 14:21:16 -0400 X-Greylist: delayed 5236 seconds by postgrey-1.27 at vger.kernel.org; Mon, 25 Apr 2011 14:21:15 EDT Message-ID: <4DB5A71A.5080802@genband.com> Date: Mon, 25 Apr 2011 10:53:46 -0600 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc11 Thunderbird/3.0.4 MIME-Version: 1.0 To: Borislav Petkov CC: Robert Whitton , Clemens Ladisch , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: Background memory scrubbing References: <18563.1303314382@jupiter.eclipse.co.uk> <20110420160125.GC2312@gere.osrc.amd.com> In-Reply-To: <20110420160125.GC2312@gere.osrc.amd.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 25 Apr 2011 16:53:47.0855 (UTC) FILETIME=[588655F0:01CC0369] X-TM-AS-Product-Ver: SMEX-8.0.0.4160-6.500.1024-18096.000 X-TM-AS-Result: No--7.126000-5.000000-31 X-TM-AS-User-Approved-Sender: No X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1907 Lines: 44 On 04/20/2011 10:01 AM, Borislav Petkov wrote: > On Wed, Apr 20, 2011 at 04:46:22PM +0100, Robert Whitton wrote: >> >>> On Wed, Apr 20, 2011 at 05:19:41PM +0200, Clemens Ladisch wrote: >>>>> Unfortunately in common with a large number of hardware platforms >>>>> background scrubbing isn't supported in the hardware (even though ECC >>>>> error correction is supported) and thus there is no BIOS option to >>>>> enable it. >>>> >>>> Which hardware platform is this? AFAICT all architectures with ECC >>>> (old AMD64, Family 0Fh, Family 10h) also have scrubbing support. >>>> If your BIOS is too dumb, just try enabling it directly (bits 0-4 of >>>> PCI configuration register 0x58 in function 3 of the CPU's northbridge >>>> device, see the BIOS and Kernel's Developer's Guide for details). >>> >>> Or even better, if on AMD, you can build the amd64_edac module >>> (CONFIG_EDAC_AMD64) and do >>> >>> echo > /sys/devices/system/edac/mc/mc/sdram_scrub_rate >>> >>> where x is the scrubbing bandwidth in bytes/sec and y is the memory >>> controller on the machine, i.e. node. >> >> Unfortunately that also isn't an option on my platform(s). There surely must be a way for a module to be able to get a mapping for each physical page of memory in the system and to be able to use that mapping to do atomic read/writes to scrub the memory. > > For such questions I've added just the right ML to Cc :). There was a thread back in 2009 cwith the subject "marching through all physical memory in software" that discussed some of the issues of a software background scrub. Chris -- Chris Friesen Software Developer GENBAND chris.friesen@genband.com www.genband.com -- 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/