Re: futex for Mach?

[Marcus Brinkmann]

On Mon, Feb 17, 2003 at 12:50:41AM -0800, Roland McGrath wrote:
> Lately I have been considering the contrary path of implementing the futex
> calls for Mach.  There are two kinds of reasons to do this.

> What do people think?

You laid out your reasons very well, and it sounds interesting enough, in
particular in terms of simplicity.

I am worried about L4, though.  If that feature is desirable in Linux and in
Mach, it is probably desirable in every other kernel as well.  Maybe there
is some L4 specific feature that saves us here, or maybe we can implement
the generic alternative you mentioned on L4.  Or maybe we can even extend L4
by a futex system call for this purpose (although I'd think that such an
extension has not the slightest chance to become official).

In other words:  We are adding a new requirement to the underlying kernel,
instead working with the minimal set of primitives.

That doesn't mean it's not the easiest and best way to just do that here and
now, just a general observation.  L4 is radically different enough so that
it does not matter if this question is postponed.  I guess it depends on how
much work either solution is and how far L4 is away.

Thanks,
Marcus

-- 
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Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
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