Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755625AbXJZIjS (ORCPT ); Fri, 26 Oct 2007 04:39:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751992AbXJZIjJ (ORCPT ); Fri, 26 Oct 2007 04:39:09 -0400 Received: from poesci.dolphinics.no ([81.175.23.36]:43669 "EHLO poesci.dolphinics.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750921AbXJZIjI convert rfc822-to-8bit (ORCPT ); Fri, 26 Oct 2007 04:39:08 -0400 X-Greylist: delayed 1866 seconds by postgrey-1.27 at vger.kernel.org; Fri, 26 Oct 2007 04:39:07 EDT To: =?iso-8859-1?Q?J=2EA=2E_Magall=F3n?= Cc: linux-kernel@vger.kernel.org Subject: Re: Opteron box and 4Gb memory References: <20071025230904.03d5f46a@werewolf> <47211172.9070606@zytor.com> <20071026004434.50c73dd3@werewolf> From: Arne Georg Gleditsch Date: Fri, 26 Oct 2007 10:08:08 +0200 In-Reply-To: <20071026004434.50c73dd3@werewolf> ("J.A. =?iso-8859-1?Q?Maga?= =?iso-8859-1?Q?ll=F3n=22's?= message of "Fri\, 26 Oct 2007 00\:44\:34 +0200") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/23.0.0 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1334 Lines: 30 "J.A. Magall?n" writes: > Software Memory Hole > When "Enabled", allows software memory remapping around the memory > hole. Options are Enabled and Disabled. > > Hardware Memory Hole > When "Enabled", allows software memory remapping around the memory > hole. Options are Enabled and Disabled. Note: this is only supported by > Rev E0 processors and above. > ( I have two Opteron 275 processors, no idea about revision) The configuration register used to to reclaim DRAM lost to an MMIO hole was introduced with revision E of the gen1 Opterons. (This feature is supposed to work both in interleaved and non-interleaved mode.) What does /proc/cpuinfo say? (On both?) (Still, even without this your BIOS should be able to map your memory so that you are able to use all 4G. Provided you disable interleaving, I can't see that there's anything stopping the BIOS from mapping the memory from node 1 to 0-2G and the memory from node 2 to 4-6G, leaving a 2G hole for MMIO and other junk. Whether your BIOS actually supports this is another matter.) -- Arne. - 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/