Re: Task destruction

[Marcus Brinkmann]

On Wed, Aug 07, 2002 at 10:06:10AM +0200, Niels Möller wrote:
> To me, the requirements for an L4 task server are quite similar to
> those for a Hurd task server. An L4 task server still needs to
> associate some "master" with each task (which could be the Hurd proc
> server or some l4-linux singleserver, for example),

I am not sure about this.  It could give all authorised threads control over
all tasks (which is what we have in Mach right now, too).

> which is
> inherited, it needs to send death notifications,

I don't think not, as this can be done by the authorised "master" (or by
anoyone authorised).  But I am not sure about how that works in L4.  Can
tasks die just by themselve?  I thought they would get an exception, and the
exception thread would request task death from the (proxy) task server.

> I think I'm also I'm assuming that ordinary hurd tasks can talk to the
> task server and create new tasks (unless they hit a limit or
> something), as if there were an unprivileged system call that creates
> a task and does the needed bookkeeping. If that's true for the hurd
> task server, but not for the L4 one, then maybe that gives some more
> opportunities for simplifying the L4 task server.

Right, in my model they could try to talk to the task server by guessing the
thread, but the "privileged thread" notion would make the task server just
drop the message.  All Hurd processes would have to talk to the Hurd proxy
task server.

Thanks,
Marcus

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