From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Date: Fri, 28 May 2010 15:41:39 +0100 Message-ID: <20100528144139.GA27140@srcf.ucam.org> References: <20100528043114.GC26177@thunk.org> <20100528103713.0a7952d9@lxorguk.ukuu.org.uk> <20100528114123.GA22947@srcf.ucam.org> <4BFFB681.1000105@nokia.com> <4BFFC5DF.5030504@nokia.com> <20100528133900.GG26177@thunk.org> <4BFFCFC7.7070302@nokia.com> <20100528142124.GA26733@srcf.ucam.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Brian Swetland Cc: Igor Stoppa , tytso@mit.edu, Alan Cox , Peter Zijlstra , LKML , Florian Mickler , Linux PM , Thomas Gleixner , Linux OMAP Mailing List , "Balbi Felipe (Nokia-D/Helsinki)" List-Id: linux-omap@vger.kernel.org On Fri, May 28, 2010 at 07:29:27AM -0700, Brian Swetland wrote: > I need to think more about the cgroups approach, but I'm pretty sure > it still suffers from wakeup race situations, and due to the > complexity of userspace (at least ours), I suspect it would risk > livelock/deadlock/priority-inversion style issues due to interaction > between different processes in different groups. I think the cgroups approach works if you assume that applications that consume wakeup events can be trusted to otherwise be good citizens. Everything that has no direct interest in wakeup events (except the generic Android userspace) can be frozen, and you can use the scheduler to make everything else Just Work. That's a rather big if, but you've got a better idea of the state of the Android app base than I do. -- Matthew Garrett | mjg59@srcf.ucam.org