On Sunday, 25 February 2007 21:31, Oleg Nesterov wrote: > On 02/25, Rafael J. Wysocki wrote: > > > > On Sunday, 25 February 2007 16:40, Aneesh Kumar wrote: > > > On 2/25/07, Aneesh Kumar <[EMAIL PROTECTED]> wrote: > > > > On 2/25/07, Rafael J. Wysocki <[EMAIL PROTECTED]> wrote: > > > > > On Sunday, 25 February 2007 15:33, Aneesh Kumar wrote: > > > > > > On 2/25/07, Rafael J. Wysocki <[EMAIL PROTECTED]> wrote: > > [--snip--] > > > > > > Thinking about this i guess we have a problem with the above approach > > > i outlined. if we have one task that is waiting on the event and more > > > than one that can generate the event then the above logic would not > > > work. Also with cases other than vfork; logic of tracking the waiting > > > task gets complex. I guess what we have right now is better. > > > > I assume by "righ now" you mean the latest version of my patch. ;-) > > > > Still, having pondered the Pavel's suggestion for a while I think it's > > doable > > without the addtitional process flag. Patch below. > > Probably I missed something, (I didn't see this patch and I missed the > start of discussion), but I can't understand this patch.
Please see http://lkml.org/lkml/2007/2/25/53 . > > +__wait_for_completion(struct completion *x, int freezable) > > { > > might_sleep(); > > > > @@ -3817,6 +3818,9 @@ void fastcall __sched wait_for_completio > > __set_current_state(TASK_UNINTERRUPTIBLE); > > spin_unlock_irq(&x->wait.lock); > > schedule(); > > + if (freezable) > > + try_to_freeze(); > > + > > spin_lock_irq(&x->wait.lock); > > } while (!x->done); > > __remove_wait_queue(&x->wait, &wait); > > @@ -3824,7 +3828,7 @@ void fastcall __sched wait_for_completio > > x->done--; > > spin_unlock_irq(&x->wait.lock); > > } > > > > .......... > > > > @@ -48,6 +48,9 @@ void refrigerator(void) > > task_unlock(current); > > return; > > } > > + if (current->vfork_done) > > + wake_up_process(current->parent); > > + > > What if current->parent doesn't have TIF_FREEZE yet? ->parent will schedule() > again, child goes to refrigerator. Now, how can we freeze the ->parent? Good point. I didn't think about it. All in all, having tried some different approaches I think that the patch at http://lkml.org/lkml/2007/2/25/80 is the right thing to do. Pavel, do you agree? Rafael - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
