Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752244AbYKKVsQ (ORCPT ); Tue, 11 Nov 2008 16:48:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751213AbYKKVr7 (ORCPT ); Tue, 11 Nov 2008 16:47:59 -0500 Received: from nlpi025.sbcis.sbc.com ([207.115.36.54]:38082 "EHLO nlpi025.prodigy.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751143AbYKKVr6 (ORCPT ); Tue, 11 Nov 2008 16:47:58 -0500 Date: Tue, 11 Nov 2008 15:47:39 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@quilx.com To: Avi Kivity cc: Andrea Arcangeli , Andrew Morton , Izik Eidus , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, chrisw@redhat.com, izike@qumranet.com Subject: Re: [PATCH 2/4] Add replace_page(), change the mapping of pte from one page into another In-Reply-To: <4919FB95.4060105@redhat.com> Message-ID: References: <1226409701-14831-1-git-send-email-ieidus@redhat.com> <1226409701-14831-2-git-send-email-ieidus@redhat.com> <1226409701-14831-3-git-send-email-ieidus@redhat.com> <20081111114555.eb808843.akpm@linux-foundation.org> <20081111210655.GG10818@random.random> <4919FB95.4060105@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Score: -2.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1170 Lines: 31 On Tue, 11 Nov 2008, Avi Kivity wrote: > Christoph Lameter wrote: > > page migration requires the page to be on the LRU. That could be changed > > if you have a different means of isolating a page from its page tables. > > > > Isn't rmap the means of isolating a page from its page tables? I guess I'm > misunderstanding something. In order to migrate a page one first has to make sure that userspace and the kernel cannot access the page in any way. User space must be made to generate page faults and all kernel references must be accounted for and not be in use. The user space portion involves changing the page tables so that faults are generated. The kernel portion isolates the page from the LRU (to exempt it from kernel reclaim handling etc). Only then can the page and its metadata be copied to a new location. Guess you already have the LRU portion done. So you just need the user space isolation portion? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/