From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933743AbXJQPrk (ORCPT ); Wed, 17 Oct 2007 11:47:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761586AbXJQPrc (ORCPT ); Wed, 17 Oct 2007 11:47:32 -0400 Received: from pat.uio.no ([129.240.10.15]:40799 "EHLO pat.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760852AbXJQPrb (ORCPT ); Wed, 17 Oct 2007 11:47:31 -0400 Subject: Re: [PATCH] nfs: fix nfs_writepage() From: Trond Myklebust To: Peter Zijlstra Cc: linux-kernel , Andrew Morton In-Reply-To: <1192635917.7573.24.camel@heimdal.trondhjem.org> References: <1192628458.27435.119.camel@twins> <1192634702.7573.10.camel@heimdal.trondhjem.org> <1192635028.27435.137.camel@twins> <1192635917.7573.24.camel@heimdal.trondhjem.org> Content-Type: text/plain Date: Wed, 17 Oct 2007 11:47:54 -0400 Message-Id: <1192636074.7573.27.camel@heimdal.trondhjem.org> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit X-UiO-Resend: resent X-UiO-ClamAV-Virus: No X-UiO-Spam-info: not spam, SpamAssassin (score=-0.3, required=12.0, autolearn=disabled, AWL=-0.298) X-UiO-Scanned: 0C5150C57426D1FB6F15355D70BCBFCC0B71E8BA X-UiO-SPAM-Test: remote_host: 129.240.10.9 spam_score: -2 maxlevel 200 minaction 2 bait 0 mail/h: 753 total 4555608 max/h 8345 blacklist 0 greylist 0 ratelimit 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-10-17 at 11:45 -0400, Trond Myklebust wrote: > On Wed, 2007-10-17 at 17:30 +0200, Peter Zijlstra wrote: > > > The thing is, swapper_space just calls ->writepage() and expects the > > page to be written out. So either the a_ops usage of swapper_space is > > deviant or NFS' is. > > Could somebody please document WTF writepage() is supposed to do, and > WTF page_mkwrite() is for? > > I thought that page_mkwrite() was supposed to finally allow us to deal > with dirty pages in a clean manner: the caller gets to tell the > filesystem that it wants the entire page written out, and then dirties > the page. What is the point if the VM then expects to be able to > circumvent this? Put differently: * _who_ is dirtying the page when the swapper is trying to write the page out? * why are they not calling either page_mkwrite() or commit_write()? Trond