On Sat, May 12, 2007 at 11:27:36AM +0200, Rafael J. Wysocki wrote: > On Saturday, 12 May 2007 10:16, Gautham R Shenoy wrote: > > > > But I am not sure if this is the case with suspend/hibernate, since we > > need to do a sys_sync() between try_freeze_tasks(FREEZE_USER_SPACE) and > > try_to_freeze_tasks(FREEZE_KERNEL_THREADS). > > From the point of view of syncing it's only necessary to make sure that we > won't freeze a kernel thread that's needed for the syncing. We can have an > additional user space task running at this point.
Ok. Say we're might have an additional user space task which is not frozen (say A). > > > > So should we perform that check in reparent_to_kthreadd() ? > > We are protected by the tasklist_lock there, no? > > Yes. Still, I think the daemonize()ed threads should clear their TIF_FREEZE > flag unconditionally right after they have called exit_mm(). So that would be > in daemonize(). > > Or, perhaps, it's better to clear TIF_FREEZE (unconditionally) in exit_mm(), > after we've done tsk->mm = NULL? Oleg, what do you think? > Is the following scenario possible? FREEZE_KERNEL_THREADS: 1) Mark all leftover threads as freezeable. That would include 'A'. 2) 'A' is now daemonised and we clear TIF_FREEZE in exit_mm(). 3) 'A' calls try_to_freeze() but doesn't enter the refrigerator. Hmm, on second thought, this shouldn't matter . The subsequent iteration will set A's TIF_FREEZE flag anyway, right? So I think it should be ok to unconditionally clear the TIF_FREEZE flag in exit_mm() after tsk->mm = NULL. > Greetings, > Rafael Thanks and Regards gautham. -- Gautham R Shenoy Linux Technology Center IBM India. "Freedom comes with a price tag of responsibility, which is still a bargain, because Freedom is priceless!" - 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/
