Re: [RFC,PATCH 2/2] change __wake_up_parent() to use filtered wakeup

[Roland McGrath <roland@redhat.com>]

> I think the check below is orthogonal to eligible_child(). 

Yes.

> Not sure
> eligible_child() can really help, but otoh it is cheap and doesn't hurt.
> But perhaps we can kill it later.

No, it's a very good check to have.  It is ideal for waitpid(ONE_PID,...)
uses, which are also probably quite common.

> > (and ->parent is perhaps
> > not right in all cases there).
> 
> I think this is right... Except I'd like to avoid using ->parent.

Agreed.  The not-right case I had in mind was do_notify_parent_cldstop
where maybe it could be ->real_parent of the untraced group_leader.

> > Your two patches as they are look safe and useful to me and I hope they can
> > go in soon.
> 
> Thanks.
> 
> Yes I think these 2 patches should be applied first, even if eligible_child()
> itself doesn't buy much. It will be cleaner if we add "real" checks on top.

Agreed.


Thanks,
Roland