Re: [patch] exit_free(), 2.5.31-A0

[Ingo Molnar]

On Tue, 13 Aug 2002, Linus Torvalds wrote:

> If you want to do this, you can do it at _clone_ time, by extending on
> the notion of "when I die, tell the parent using signal X" and making
> that notion be a more generic "when I die, do X", where "X" migh include
> updating some parent tables instead of sending a signal.
> 
> But the magic "exit_write()" has to die.

think about it - we have the *very same* problem in kernel-space, and we
had it for years. People wanted to get rid of parent notification in
helper processes for ages. A thread cannot free its own stack. We now can
do it only with very special care and atomicity. The same thing cannot be
done by user-space, because it has no 'atomic change and sys_exit()'
operation at its hands. This capability is that the syscall provides -
perhaps it should be called 'exit_atomic()' instead?

(we got rid of all signal passing in the main fabric of pthreads - and
that's done rightfully so. Futexes are used for message passing and
eventing.)

	Ingo