On 02/22, Tejun Heo wrote: > > > So I think it too should somehow interact with freezable_schedule/etc. > > You mean freezer_do_not_count(), right? yes, > As long as the task is > guaranteed to be trapped by signal stop afterwards (and they are), we > likely can use them the same way. The only thing to be careful about > would be ensuring that we don't end up flipping group level frozen > state inbetween. Would something like that work? I have no idea because I do not understand what exactly do you mean ;) However. Thinking more about this, I am not sure my concerns were valid. Yes, cg freezer can "hang" if it races with vfork(). But probably we should blame vfork(), not freezer. The problem is, even ^Z can "hang" if the foreground process does vfork() and the new child stops before exit/exec. Now I recall that I even tried to make a patch to fix this using ERESTART_RESTARTBLOCK, but had some nasty problems with blocked signals... de_thread() should use freezable_schedule() in TASK_KILLABLE too. Currently it doesn't, but only because we have other (much more serious) problems with cred_guard_mutex/exec. However, this is is fine wrt cg freezer, other threads can't be frozen exactly because it is killable. Anything else does freezer_do_not_count() in TASK_KILLABLE and waits for another freezable process? So it seems I have to take my words back, perhaps we can forget about freezable_schedule/etc. Oleg.
