From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759332AbZEFMbE (ORCPT ); Wed, 6 May 2009 08:31:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754581AbZEFMav (ORCPT ); Wed, 6 May 2009 08:30:51 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:39599 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754115AbZEFMav (ORCPT ); Wed, 6 May 2009 08:30:51 -0400 Date: Wed, 6 May 2009 14:30:30 +0200 From: Ingo Molnar To: Rik van Riel Cc: "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , linux-mm@kvack.org, mingo@redhat.com, akpm@linux-foundation.org Subject: Re: [PATCH] x86: 46 bit PAE support Message-ID: <20090506123030.GW25203@elte.hu> References: <20090505172856.6820db22@cuia.bos.redhat.com> <4A00ED83.1030700@zytor.com> <4A0180AB.20108@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A0180AB.20108@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Rik van Riel wrote: > H. Peter Anvin wrote: >> Rik van Riel wrote: >>> Testing: booted it on an x86-64 system with 6GB RAM. Did you really think >>> I had access to a system with 64TB of RAM? :) >> >> No, but it would be good if we could test it under Qemu or KVM with an >> appropriately set up sparse memory map. > > I don't have a system with 1TB either, which is how much space > the memmap[] would take... Not if the physical layout is sparse. I.e. something silly like: BIOS-e820: 0000000100000000 - 0000000140000000 (usable) BIOS-e820: 0000200000000000 - 0000200040000000 (usable) Which is 1GB of RAM at 4GB physical offset, and another 1GB of RAM at 32 TB physical offset. Takes two gigs of real RAM and a kernel modified with your patch, to not get confused by this :-) Ingo