From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id C30296B004F for ; Wed, 6 May 2009 08:30:07 -0400 (EDT) Date: Wed, 6 May 2009 14:30:30 +0200 From: Ingo Molnar 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> Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , linux-mm@kvack.org, mingo@redhat.com, akpm@linux-foundation.org List-ID: * 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org