Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754378AbYJ1Xyl (ORCPT ); Tue, 28 Oct 2008 19:54:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753316AbYJ1Xyd (ORCPT ); Tue, 28 Oct 2008 19:54:33 -0400 Received: from mail.crca.org.au ([67.207.131.56]:47412 "EHLO crca.org.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753296AbYJ1Xyc (ORCPT ); Tue, 28 Oct 2008 19:54:32 -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 10:54:29 +1100 Message-Id: <1225238069.9661.61.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: 1752 Lines: 44 Hi Miklos. On Wed, 2008-10-29 at 00:45 +0100, 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? > > No, it already passed that, before the filesystem got frozen. But it > doesn't matter, in either case i_mutex will already have been taken by > the VFS and it won't be released until the request completely > finishes. I think we're making different assumptions. I'm assuming that one of those solutions we already discussed is implemented, such that we don't start freezing a new filesystem until all the requests for the current filesystem are dealt with. Perhaps I should come up with a new version of the patch that implements that. 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/