Re: [PATCH] Re: futex and timeouts

Rusty Russell (rusty@rustcorp.com.au)
Fri, 15 Mar 2002 19:49:04 +1100

In message <20020315060829.L4836@parcelfarce.linux.theplanet.co.uk> you write:
> On Fri, Mar 15, 2002 at 04:39:50PM +1100, Rusty Russell wrote:
> > Yep, sorry, my mistake. I suggest make it a relative "struct timespec
> > *" (more futureproof that timeval). It would make sense to split the
> > interface into futex_down and futex_up syuscalls, since futex_up
> > doesn't need a timeout arg, but I haven't for the moment.
>
> Why waste a syscall? The user is going to be using a library
> wrapper. They don't have to know that futex_up() calls sys_futex(futex,
> FUTEX_UP, NULL);

My bad. There was a mistake in the patch (ie. I didn't actually do
this).

OTOH, shades of fcntl! Syscalls are not "wasted": one for every
fundamental operation makes *sense*. If I were doing it with timeouts
from scratch, I'd definitely have done two syscalls. As it is, the
"op" arg gives us a chance for more overloading in future.

Hope that clarifies,
Rusty.

--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/