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. Perhaps it makes sense to make some other changes first. For example, kill CPU_TASKS_FROZEN bit. 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. 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). Perhaps we can think a bit more :) Oleg. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
