From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754864AbYDIKJu (ORCPT ); Wed, 9 Apr 2008 06:09:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752740AbYDIKJn (ORCPT ); Wed, 9 Apr 2008 06:09:43 -0400 Received: from poesci.dolphinics.no ([81.175.23.36]:38725 "EHLO poesci.dolphinics.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752657AbYDIKJm (ORCPT ); Wed, 9 Apr 2008 06:09:42 -0400 X-Greylist: delayed 1180 seconds by postgrey-1.27 at vger.kernel.org; Wed, 09 Apr 2008 06:09:42 EDT From: Arne Georg Gleditsch To: Andi Kleen Cc: "Zhao Forrest" , discuss@x86-64.org, linux-kernel@vger.kernel.org, yhlu.kernel@gmail.com, mingo@elte.hu, ak@suse.de Subject: Re: Does Linux have plan to support memory hole remapping? References: <87iqyro3rc.fsf@basil.nowhere.org> Date: Wed, 09 Apr 2008 11:50:00 +0200 In-Reply-To: <87iqyro3rc.fsf@basil.nowhere.org> (Andi Kleen's message of "Wed, 09 Apr 2008 10:01:59 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen writes: > "Zhao Forrest" writes: >> >> As we can see from above information that the physical memory in system >> is 32768MB(32GB). However OS is only using about >> (32768-512)MB(MemTotal: 33010240 kB). Does this mean that this >> linux kernel can't use the physical memory remapped >> from (4G-512M, 4G) to (32G, 32G+512M)? > > The linux kernel can only use the memory passed to it by the BIOS. > Sometimes they need special BIOS setup options to enable remapping. If > there are no such options and you can't upgrade it you're out of luck Hm, wouldn't the given e820 map and mtrr listing indicate that 512M were actually remapped to 32G+ in this case? -- Arne.