On Monday, 21 May 2007 22:54, Oleg Nesterov wrote: > On 05/21, Rafael J. Wysocki wrote: > > > > On Monday, 21 May 2007 21:33, Alan Stern wrote: > > > Raphael: > > > > > > Are we now committed to making freezable workqueues always > > > singlethreaded? Is it at all likely to change back? Or should I > > > introduce a "create_singlethread_freezeable_workqueue" macro? > > > > This was done as a quick fix of an issue with one driver that started to use > > (broken) freezable workqueues when we were not watching. ;-) > > > > We are going to have multithread freezable workqueues as well, but that'll > > take some time. We've discussed this a bit with Oleg and I believe he has an > > idea of how it can be done cleanly. > > No, I don't have an idea how to do this cleanly currently. > > We can fix them right now with Rafael's "take_over_work() + migrate_sequence" > patch, feel free to send it. Not perfect, but should work. Well, there's no hurry with that, I think. If there's a clear case in which such a workqueue would be useful, we can do this. For now, I don't see one. > Perhaps it makes sense to make some other changes first. For example, kill > CPU_TASKS_FROZEN bit. That's possible, but the microcode driver uses it in a nontrivial way and that should be taken into consideration. > Next. We can't make all wqs freezeable, but if we add freezer_exempt/PF_FE_XXX > we can freeze them all for cpu_up/cpu_down, this also make things simpler. Yes. > Note that we don't have a good way to use take_over_work() for !freezeable wq. > 2.6.21 does kthread_stop() first, this is deadlockable because we may have > a work_struct on ->worklist which also calls kthread_stop(). Perhaps it makes > sense to wait until kthread_stop() will be reworked (should be soon). Yes, I think we should wait until the kthread-related things settle. > Perhaps we can think a bit more :) Sure, that won't hurt. :-) Greetings, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
