From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752245AbXDBQSS (ORCPT ); Mon, 2 Apr 2007 12:18:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752655AbXDBQSS (ORCPT ); Mon, 2 Apr 2007 12:18:18 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:50349 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752346AbXDBQSQ (ORCPT ); Mon, 2 Apr 2007 12:18:16 -0400 Date: Mon, 2 Apr 2007 09:18:16 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Andi Kleen cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Martin Bligh , linux-mm@kvack.org, KAMEZAWA Hiroyuki Subject: Re: [PATCH 1/4] x86_64: Switch to SPARSE_VIRTUAL In-Reply-To: <200704011246.52238.ak@suse.de> Message-ID: References: <20070401071024.23757.4113.sendpatchset@schroedinger.engr.sgi.com> <20070401071029.23757.78021.sendpatchset@schroedinger.engr.sgi.com> <200704011246.52238.ak@suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 1 Apr 2007, Andi Kleen wrote: > Or do you have overlaps with other memory (I think you have) We may get into a case where some page structs are physically located on other nodes if there are no holes between nodes. This would be particularly significant for 64MB node sizes using numa emulation. But there it really does not matter where the real memory is located. (this is really inherent in sparsemems way of mapping memory). > In that case you have to handle the overlap in change_page_attr() Why would we use change_page_attr on page structs? I can see that the pages themselves should be subject to change_page_attr but why the page_structs? I think the system would panic if one would set page structs to read only.