From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 24 Apr 2008 10:36:59 +0900 From: KAMEZAWA Hiroyuki Subject: Re: Warning on memory offline (and possible in usual migration?) Message-Id: <20080424103659.90a1006d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20080414145806.c921c927.kamezawa.hiroyu@jp.fujitsu.com> <20080422045205.GH21993@wotan.suse.de> <20080422165608.7ab7026b.kamezawa.hiroyu@jp.fujitsu.com> <20080422094352.GB23770@wotan.suse.de> <20080423004804.GA14134@wotan.suse.de> <20080423114107.b8df779c.kamezawa.hiroyu@jp.fujitsu.com> <20080423025358.GA9751@wotan.suse.de> <20080423124425.5c80d3cf.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Nick Piggin , "linux-mm@kvack.org" , Andrew Morton , GOTO List-ID: On Wed, 23 Apr 2008 10:50:33 -0700 (PDT) Christoph Lameter wrote: > On Wed, 23 Apr 2008, KAMEZAWA Hiroyuki wrote: > > > In set_page_dirty_nobuffers()case , it just makes a page to be dirty. We can't > > see whether a page is really up-to-date or not when PagePrivate(page) && > > !PageUptodate(page). This is used for a page which contains some data > > to be written out. (part of buffers contains data.) > > So its safe to migrate a !Uptodate page if it contains buffers? Note that > the migration code reattaches the buffer to the new page in > buffer_migrate_page(). > I think it's safe because it reattaches buffers as you explained. under migration 1. a page is locked. 2. buffers are reattached. 3. a PG_writeback page are not migrated. So, it seems safe. Thanks, -Kame -- 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