From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755864Ab3AQVzl (ORCPT ); Thu, 17 Jan 2013 16:55:41 -0500 Received: from e9.ny.us.ibm.com ([32.97.182.139]:42222 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752293Ab3AQVzk (ORCPT ); Thu, 17 Jan 2013 16:55:40 -0500 Message-ID: <50F8734C.2080906@linux.vnet.ibm.com> Date: Thu, 17 Jan 2013 13:55:24 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: paul.szabo@sydney.edu.au CC: psz@maths.usyd.edu.au, 695182@bugs.debian.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC] Reproducible OOM with just a few sleeps References: <201301172104.r0HL4F9k005128@como.maths.usyd.edu.au> In-Reply-To: <201301172104.r0HL4F9k005128@como.maths.usyd.edu.au> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13011721-7182-0000-0000-000004877A6C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/17/2013 01:04 PM, paul.szabo@sydney.edu.au wrote: >>> On my large machine, 'free' fails to show about 2GB memory ... >> You probably have a memory hole. ... >> The e820 map (during early boot in dmesg) or /proc/iomem will let you >> locate your memory holes. > > Now that my machine is running an amd64 kernel, 'free' shows total Mem > 65854128 (up from 64447796 with PAE kernel), and I do not see much > change in /proc/iomem output (below). Is that as should be? Yeah, that all looks sane. Your increased memory is because your 64GB machine had some of its memory mapped _above_ the 64GB physical memory limit that PAE has. /proc/iomem is generally just a dump of what the hardware *is*, so it shouldn't change between kernels.