From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763386AbXGFJxM (ORCPT ); Fri, 6 Jul 2007 05:53:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757928AbXGFJw6 (ORCPT ); Fri, 6 Jul 2007 05:52:58 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:57648 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757261AbXGFJw5 (ORCPT ); Fri, 6 Jul 2007 05:52:57 -0400 From: "Rafael J. Wysocki" To: Miklos Szeredi Subject: Re: [RFC][PATCH -mm] PM: Do not sync filesystems from within the freezer Date: Fri, 6 Jul 2007 12:00:36 +0200 User-Agent: KMail/1.9.5 Cc: nigel@suspend2.net, benh@kernel.crashing.org, pavel@ucw.cz, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, mjg59@srcf.ucam.org, oliver@neukum.org, paulus@samba.org, mingo@elte.hu References: <200707041658.59588.rjw@sisk.pl> <200707061914.02972.nigel@nigel.suspend2.net> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707061200.37035.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday, 6 July 2007 11:31, Miklos Szeredi wrote: > > > > On Fri, 2007-07-06 at 09:13 +0200, Miklos Szeredi wrote: > > > > > > > > > > Another myth, that has been debunked already. The problem is: how do > > > > > you define fuse processes? There's no theoretical or even practial > > > > > way to do that. > > > > > > > > It could if they told the kernel via some black magic ... > > > > > > > > But that still suck. The freezer sucks :-) > > > > > > Yeah, and it wouldn't work in practice, since the auxilary tasks might > > > be part of a library which is not even aware of being used by a "fuse > > > task". > > > > This is why I think the whole concept of filesystems in userspace is broken. > > Trying to shift things that need special privilege and special handling to > > userspace is just asking for trouble. > > I'm not claiming fuse doesn't introduce problems. I've been tackling > those problems for a number of years now. Suspend/hibernate is just > the next thing that needs looking at. > > Just blaming either suspend or fuse for these problems is unproductive > and stupid. Well, the "stupid" part is a bit offensive, don't you think? > The problems _are_ solvable if not always simply. Agreed. > > You can say it's the kernel code's fault, but then you have to > > explain why it's only fuse (yeah ok, and XFS) that have problems. > > I'm not faulting anythig. My opinion, is that the freezer is not > needed for suspend, and removing it will not just solve the problems > with fuse but several others. It probably needs a lot of work, but > hey, that's why we are here. > > The patch posted by Rafael, which lets the freezer skip uninterrupible > tasks is a step in the right direction. Thanks. BTW, I think that this is just less radical than the change proposed by Matthew and it should address the underlying problems. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth