Re: [PATCH] Futexes IV (Fast Lightweight Userspace Semaphores)

Rusty Russell
2002-03-20T06:18:01Z

On 18 Mar 2002 20:05:22 -0800
Ulrich Drepper <drepper@redhat.com> wrote:

> On Mon, 2002-03-18 at 19:28, Rusty Russell wrote:
>
> > What do you WANT in a kernel primitive then? Given that we now have mutexes,
> > what else do we need to make pthreads relatively painless?
>
> I think wrt to the mutexes only wake-all is missing. I don't think that
> semaphore semantic is needed in the kernel.

And have all the waiters exit with errno = EAGAIN? ("You didn't get it but
someone wanted you all woken").

It can be done, I'd have to see if is sufficient to implement pthreads.

Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.