On 04/30, Oleg Nesterov wrote: > > On 04/29, Colin Cross wrote: > > > > Avoid waking up every thread sleeping in a sigtimedwait call during > > suspend and resume by calling a freezable blocking call. > > This doesn't explain why do want this change... > > OK, probably to avoid -EAGAIN from sigtimedwait() if the freezer wakes > up the caller. > > > --- a/kernel/signal.c > > +++ b/kernel/signal.c > > @@ -2845,7 +2845,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t > > *info, > > recalc_sigpending(); > > spin_unlock_irq(&tsk->sighand->siglock); > > > > - timeout = schedule_timeout_interruptible(timeout); > > + timeout = freezable_schedule_timeout_interruptible(timeout); > > And I guess freezable_schedule_timeout_interruptible() is added by > http://marc.info/?l=linux-kernel&m=136727195719575 ... > > +#define freezable_schedule_timeout_interruptible(timeout) > \ > +({ > \ > + long __retval; > \ > + freezer_do_not_count(); > \ > + __retval = schedule_timeout_interruptible(timeout); > \ > + freezer_count(); > \ > + __retval; > \ > +}) > > How this can help? > > The task will be interrupted anyway and the syscall will return > -EAGAIN, this only changes the time when try_to_freeze() is called.
OK, I wasn't cced, I have found another patch http://marc.info/?l=linux-kernel&m=136727200519602 which should make a difference, it won't be woken if PF_FREEZER_SKIP was already set. This is racy, but it seems that "avoid -EAGAIN" was not your goal... > For what? The task will call do_signal/try_to_freeze really "soon". It seems that you want to speed up the freezing. Oleg. -- 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/
