Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946371AbWKJKhT (ORCPT ); Fri, 10 Nov 2006 05:37:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932841AbWKJKhS (ORCPT ); Fri, 10 Nov 2006 05:37:18 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:18400 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S932839AbWKJKhQ (ORCPT ); Fri, 10 Nov 2006 05:37:16 -0500 Date: Fri, 10 Nov 2006 11:36:50 +0100 From: Pavel Machek To: Alan Cox Cc: "Rafael J. Wysocki" , Alasdair G Kergon , Eric Sandeen , Andrew Morton , linux-kernel@vger.kernel.org, dm-devel@redhat.com, Srinivasa DS , Nigel Cunningham , David Chinner Subject: Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex Message-ID: <20061110103650.GE3196@elf.ucw.cz> References: <20061107183459.GG6993@agk.surrey.redhat.com> <200611091652.34649.rjw@sisk.pl> <20061109160003.GA24156@elf.ucw.cz> <200611092059.48722.rjw@sisk.pl> <20061109211722.GA2616@elf.ucw.cz> <1163154249.7900.19.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1163154249.7900.19.camel@localhost.localdomain> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1100 Lines: 26 HI! > > Why not simply &~ PF_NOFREEZE on that particular process? Filesystems > > are free to use threads/work queues/whatever, but refrigerator should > > mean "no writes to filesystem" for them... > > You can't go around altering the flags of another process - what locking > are you relying upon for this ? Well, my idea was for process to &~ PF_NOFREEZE on itself. We are currently (kernel/power/process.c) using &p->sighand->siglock for some accesses, and no locking for others. There were some attempts to fix this, but they led to problems, and we are not hitting any problems... part of reason is that we hot-unplug non-boot cpus before freezing processes, so we are running UP at that point. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/