Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754143AbYJ1X6m (ORCPT ); Tue, 28 Oct 2008 19:58:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752332AbYJ1X6d (ORCPT ); Tue, 28 Oct 2008 19:58:33 -0400 Received: from mail.crca.org.au ([67.207.131.56]:52780 "EHLO crca.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751771AbYJ1X6d (ORCPT ); Tue, 28 Oct 2008 19:58:33 -0400 X-Bogosity: Ham, spamicity=0.000000 Subject: Re: [linux-pm] Freezer: Don't count threads waiting for frozen filesystems. From: Nigel Cunningham To: Miklos Szeredi Cc: linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: References: <1224886068.6478.21.camel@nigel-laptop> <1225106427.26724.5.camel@nigel-laptop> <200810271237.40049.rjw@sisk.pl> <1225107607.26724.9.camel@nigel-laptop> <1225141168.26724.23.camel@nigel-laptop> <1225145607.26724.54.camel@nigel-laptop> <1225235054.9661.37.camel@nigel-laptop> <1225235860.9661.42.camel@nigel-laptop> <1225237298.9661.55.camel@nigel-laptop> Content-Type: text/plain Organization: Christian Reformed Churches of Australia Date: Wed, 29 Oct 2008 10:58:29 +1100 Message-Id: <1225238309.9661.65.camel@nigel-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1751 Lines: 47 Hi. On Wed, 2008-10-29 at 00:50 +0100, Miklos Szeredi wrote: > On Wed, 29 Oct 2008, Miklos Szeredi wrote: > > On Wed, 29 Oct 2008, Nigel Cunningham wrote: > > > Hi. > > > > > > On Wed, 2008-10-29 at 00:24 +0100, Miklos Szeredi wrote: > > > > On Wed, 29 Oct 2008, Nigel Cunningham wrote: > > > > > Remember, though, that we're only freezing fuse at the moment, and > > > > > strictly one filesystem at a time. We can thus happily wait for the > > > > > i_mutex taken by some other process to be released. > > > > > > > > Not going to work: you need to wait for all requests to be finished, > > > > but those might depend on some other fuse filesystem which has already > > > > been frozen. > > > > > > Okay. In that case, am I right in thinking that the request waiting on > > > the frozen filesystem will be stuck in request_wait_answer, > > > > Yes. > > > > > and the > > > userspace process that was trying to satisfy the request will be stuck > > > in the FUSE_MIGHT_FREEZE call that was invoked for the frozen > > > filesystem? > > Sorry, I misunderstood this. Yes you're right, in the case of one > fuse filesystem relying on another to complete the request the already > frozen one will be stuck in FUSE_MIGHT_FREEZE(). > > How does that help? Well, my next question was going to be: can we find a way to know that the userspace process we're waiting on was frozen? If we can know that, then perhaps we can apply that knowledge in this thread to avoid a freezing failure. Regards, Nigel -- 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/