On 09/05, Tejun Heo wrote: > > Hello, Oleg. > > On Sun, Sep 04, 2011 at 08:46:26PM +0200, Oleg Nesterov wrote: > > > @@ -72,10 +72,6 @@ bool __refrigerator(bool check_kthr_stop) > > > schedule(); > > > } > > > > > > - spin_lock_irq(¤t->sighand->siglock); > > > - recalc_sigpending(); /* We sent fake signal, clean it up */ > > > - spin_unlock_irq(¤t->sighand->siglock); > > > - > > > > Why? This recalc_sigpending() makes sense imho. Otherwise the user-space > > tasks (almost) always return with TIF_SIGPENDING. May be we can do this > > under "if (PF_KTRHREAD)". > > PF_KTHREAD no longer gets TIF_SIGPENDING set, so... Yes, > > For example. Suppose the user-space task does wait_event_freezable()... > > > > Hmm. OTOH, wait_event_freezable() looks wrong anyway... So probably > > this doesn't matter. ptrace_stop/get_signal_to_deliver doesn't need > > this, probably we do not care about the other callers. > > Can you elaborate on it being wrong? Do you mean the possibility of > leaking spurious TIF_SIGPENDING? Perhaps it is correct... Just I do not understand what it should do. I thought it is "wait_for_event && do_not_block_freezer". And at first glance the code looks as if it tries to do this. Say, in the "likely" case we restart wait_event_interruptible() after refrigerator(). But this looks racy. Suppose that freezing() is already false when try_to_freeze() or __refrigerator() is called. Say, cgroup_freezer does freeze_task() + __thaw_task(). Why it returns -ERESTARTSYS in this case? And if it can be used by the userspace thread, then we should probably do recalc_sigpending() somewhere, otherwise wait_event_freezable() will always return -ERESTARTSYS after __refrigerator(). Oleg. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
