Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030279AbWAKGxM (ORCPT ); Wed, 11 Jan 2006 01:53:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030269AbWAKGxM (ORCPT ); Wed, 11 Jan 2006 01:53:12 -0500 Received: from omx1-ext.sgi.com ([192.48.179.11]:19855 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S1030279AbWAKGxL (ORCPT ); Wed, 11 Jan 2006 01:53:11 -0500 Date: Tue, 10 Jan 2006 22:52:58 -0800 (PST) From: Christoph Lameter To: Andrew Morton cc: kamezawa.hiroyu@jp.fujitsu.com, cpw@sgi.com, linux-kernel@vger.kernel.org, lhms-devel@lists.sourceforge.net, taka@valinux.co.jp Subject: Re: [PATCH 5/5] Direct Migration V9: Avoid writeback / page_migrate() method In-Reply-To: <20060110224905.514213de.akpm@osdl.org> Message-ID: References: <20060110224114.19138.10463.sendpatchset@schroedinger.engr.sgi.com> <20060110224140.19138.84122.sendpatchset@schroedinger.engr.sgi.com> <20060110220314.70e5793b.akpm@osdl.org> <20060110224905.514213de.akpm@osdl.org> 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 Content-Length: 752 Lines: 26 On Tue, 10 Jan 2006, Andrew Morton wrote: > So let's see. Suppose the kernel is about to dink with a page's buffer > ring. It does: > > get_page(page); > lock_page(page); > dink_with(page_buffers(page)); > > how do these patches ensure that the page doesn't get migrated under my > feet? The page is locked when buffer_migrate_page is called. Thus lock_page will block. If the refcount was increased before the migration code does the lock on the tree_lock then the migration will be aborted. - 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/