On Friday, 13. February 2009, Matthew Garrett wrote: > On Fri, Feb 13, 2009 at 06:24:09AM -0800, Brian Swetland wrote: > > I think the "what happens when a process crashes and its suspend > > inhibits are released" issue still needs some thought -- if say a > > background/service process crashes while holding a lock we want to > > have the process be able to be restarted by init or whatnot without > > having to wait for some other activity. This is a real example we > > ran into in the past -- telephony process crashes and the device > > doesn't get back on the network until the user presses a key, an > > alarm fires, etc. > > The easiest way to handle this would seem to be a multiplexing daemon > that implements whatever policy a specific use case has. In your case > this would do its own reference counting and then implement timeouts for > specific applications, perhaps with some kind of acl so arbitrary apps > can't take a lock and then fall down a well. If you've got a > sufficiently advanced init then you'd be able to flag an application as > being in restart state and then have the daemon hold the lock until the > application chooses to reacquire it or not, which seems more flexible > than any purely kernel-based implementation. That's racy. By the time the daemon notices that a process crashed, the kernel might already have triggered suspend. userspace might then be frozen before it can accuire the 'process restarting' lock. I also wonder, if it is immanently racy to use userspcae communication (client/daemon) for suspend locks. What if the daemon is already frozen when a client sends a lock request request? Uli -- ------- ROAD ...the handyPC Company - - - ) ) ) Uli Luckas Head of Software Development ROAD GmbH Bennigsenstr. 14 | 12159 Berlin | Germany fon: +49 (30) 230069 - 62 | fax: +49 (30) 230069 - 69 url: www.road.de Amtsgericht Charlottenburg: HRB 96688 B Managing director: Hans-Peter Constien _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
