On Thu, Apr 04, 2013 at 06:38:36PM +0200, Peter Zijlstra wrote: > On Thu, 2013-04-04 at 15:31 +0200, Daniel Vetter wrote: > > Hm, I guess your aim with the TASK_DEADLOCK wakeup is to bound the > > wait > > times of older task. > > No, imagine the following: > > struct ww_mutex A, B; > struct mutex C; > > task-O task-Y task-X > A > B > C > C > B > > At this point O finds that Y owns B and thus we want to make Y 'yield' > B to make allow B progress. Since Y is blocked, we'll send a wakeup. > However Y is blocked on a different locking primitive; one that doesn't > collaborate in the -EDEADLK scheme therefore we don't want the wakeup to > succeed. I'm confused to why the above is a problem. Task-X will eventually release C, and then Y will release B and O will get to continue. Do we have to drop them once the owner is blocked? Can't we follow the chain like the PI code does? -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
