From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760635AbXGDKTN (ORCPT ); Wed, 4 Jul 2007 06:19:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757539AbXGDKTA (ORCPT ); Wed, 4 Jul 2007 06:19:00 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:48441 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757433AbXGDKS7 (ORCPT ); Wed, 4 Jul 2007 06:18:59 -0400 From: "Rafael J. Wysocki" To: Miklos Szeredi Subject: Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend to RAM pathway Date: Wed, 4 Jul 2007 12:26:33 +0200 User-Agent: KMail/1.9.5 Cc: paulus@samba.org, oliver@neukum.org, benh@kernel.crashing.org, mjg59@srcf.ucam.org, linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20070703042916.GA17240@srcf.ucam.org> <18059.21555.317415.928416@cargo.ozlabs.ibm.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200707041226.34799.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, 4 July 2007 10:26, Miklos Szeredi wrote: > > > That's weird, I never had a suspend problem due to a fuse mount, > > > though I have them all the time. And I suspect, that even the sync() > > > > Well, I don't either, because we don't freeze processes on > > powerbooks. But I have heard that other people have problems with > > suspending with a fuse filesystem mounted. Maybe the difference is > > whether or not the filesystem is writable? > > > > > thing that suspend does is not the real cause, because sync() actually > > > does nothing in fuse filesystems. > > > > It's not the filesystem sync method, as I understand it, it's that if > > there are dirty pages in the page cache for files on the fuse > > filesystem, > > Currently fuse doesn't produce dirty pages. Normal writes are done > synchronously, and writable mmap is not supported. So sync() should > really be a no-op for fuse. > > > the system will initiate a write-out on them and wait for it to > > finish. But if the fuse userspace is frozen, the write-out will > > never complete. > > Maybe there is some other fs operation being done, possibly not > directly, but by waiting for a kernel thread, that does that. We're going to limit the freezing of kernel threads to the ones that explicitly want to be frozen, so if that's the case, then I think it'll be fixed soon. > It would be nice, if someone who can reproduce the deadlock could > debug it. Agreed. > Does sysrq still work during suspend? Yes, it should work. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth