Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757720AbXFBIva (ORCPT ); Sat, 2 Jun 2007 04:51:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753908AbXFBIvW (ORCPT ); Sat, 2 Jun 2007 04:51:22 -0400 Received: from gw1.cosmosbay.com ([86.65.150.130]:43403 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752166AbXFBIvW (ORCPT ); Sat, 2 Jun 2007 04:51:22 -0400 Message-ID: <46612F80.2070906@cosmosbay.com> Date: Sat, 02 Jun 2007 10:51:12 +0200 From: Eric Dumazet User-Agent: Thunderbird 1.5.0.12 (Windows/20070509) MIME-Version: 1.0 To: Mike Richards CC: linux-kernel@vger.kernel.org Subject: Re: Missing RAM on x86_64 References: <516d7fa80706012151m32facb87nafb68811c784fa54@mail.gmail.com> In-Reply-To: <516d7fa80706012151m32facb87nafb68811c784fa54@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [86.65.150.130]); Sat, 02 Jun 2007 10:51:19 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2504 Lines: 62 Mike Richards a ?crit : > Hi, I appear to be missing quite a bit of RAM on an x86_64 system. I > have 1GB installed, but 'free' only shows 878MB: > > pokey$ free -m > total used free shared buffers cached > Mem: 878 571 306 0 52 332 > -/+ buffers/cache: 186 691 > Swap: 1023 0 1023 > > I'm used to seeing a little bit of RAM missing with 32bit systems, but > 146MB seems a bit much. The part of dmesg that concerns the RAM is > shown below. Anyone know what's up here? Is this normal for an x86_64 > system? > > Linux version 2.6.20.11 (root@pokey) (gcc version 4.1.2) #1 SMP Thu > May 24 18:29:52 GMT 2007 > Command line: auto BOOT_IMAGE=2.6.20.11 rw root=801 > BIOS-provided physical RAM map: > BIOS-e820: 0000000000000000 - 000000000009fc00 (usable) > BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved) > BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved) > BIOS-e820: 0000000000100000 - 0000000037fd0000 (usable) > BIOS-e820: 0000000037fd0000 - 0000000037fde000 (ACPI data) > BIOS-e820: 0000000037fde000 - 0000000038000000 (ACPI NVS) > BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved) > BIOS-e820: 00000000fee00000 - 00000000fef00000 (reserved) > BIOS-e820: 00000000ff780000 - 0000000100000000 (reserved) I would say your BIOS needs an update or some tweakings. The (usable) parts that it gives to the OS (linux) are : 0000000000000000 - 000000000009fc00 0000000000100000 - 0000000037fd0000 Thats not 1024 MB, but 892 MB Here is the output on a 16 GB x86_64 machine BIOS-provided physical RAM map: BIOS-e820: 0000000000000000 - 000000000009fc00 (usable) BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved) BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved) BIOS-e820: 0000000000100000 - 000000007fff0000 (usable) BIOS-e820: 000000007fff0000 - 000000007ffff000 (ACPI data) BIOS-e820: 000000007ffff000 - 0000000080000000 (ACPI NVS) BIOS-e820: 00000000ff780000 - 0000000100000000 (reserved) BIOS-e820: 0000000100000000 - 0000000480000000 (usable) On node 0 totalpages: 2097039 On node 1 totalpages: 2097152 total of 4194078 pages (while exact 16GB should be 4194304 pages) - 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/