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Re: emulating no-senders notifications in L4?
From: |
Niels Möller |
Subject: |
Re: emulating no-senders notifications in L4? |
Date: |
20 Dec 2001 22:33:38 +0100 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 |
Jean Wolter <address@hidden> writes:
> address@hidden (Niels Möller) writes:
>
> > When thinking some more, I realize that you can perhaps distribute the
> > "central" registry, giving the owner of each receive right the
> > reponsibility to keep track of all corresponding the send rights. Is
> > that what you're thinking of?
>
> Thats right, that was what Michael and Sven implemented when they did
> a Mach emulation for L3 (the precursor of L4). Michael mentioned it
> some weeks ago and there is a paper on our web sites about it
> (http://os.inf.tu-dresden.de/~hohmuth/dir/pub).
Thanks for explaining this. I guess I should read that paper.
> > Nice idea. A few potential drawbacks is
> > that
> >
> > 1. Transfer of port-rights gets more complicated. In particular the
> > transfer of receive rights becomes more difficult. Does the hurd
> > ever need transfer of receive rights?
>
> Sure you would have to contact the owner of the port to transfer a
> send right. How often does this happen?
Hmm, I guess most cases port rights that are passed on to other tasks
are newly created ones (happens at open(), for instance, and ports
handed out by the auth server).
> And the main question is: Does Hurd actually use the possibility to
> transfer receive rights?
I'd like to know that too.
> > 2. You get a lot more parties that are interested in task death
> > events. The task server to keep track of all subscriptions.
>
> How many servers are there? How often are tasks created and destroyed
> compared to the number of ipc which would have to go through the port
> server?
Probably not more than manageble.
> > So far, I've been thinking of delegation (i.e. transfer of send
> > rights) as something that is under complete control of whoever wants
> > to give a way a right, [...]
> Is that information hiding a requirement or just nice to have? If it
> is required you need the port server, if not...
It is somewhat subtle change, but I don't think it is terribly
important.
Regards,
/Niels
- Re: emulating no-senders notifications in L4?, (continued)
- Re: emulating no-senders notifications in L4?, Yoshinori K. Okuji, 2001/12/20
- Re: emulating no-senders notifications in L4?, Niels Möller, 2001/12/20
- Re: emulating no-senders notifications in L4?, Jean Wolter, 2001/12/20
- Re: emulating no-senders notifications in L4?, Niels Möller, 2001/12/20
- Re: emulating no-senders notifications in L4?, Marcus Brinkmann, 2001/12/20
- Re: emulating no-senders notifications in L4?, Jean Wolter, 2001/12/20
- Re: emulating no-senders notifications in L4?,
Niels Möller <=
- Re: emulating no-senders notifications in L4?, Marcus Brinkmann, 2001/12/20
- Re: emulating no-senders notifications in L4?, Roland McGrath, 2001/12/20
- Re: emulating no-senders notifications in L4?, Thomas Bushnell, BSG, 2001/12/20
- Re: emulating no-senders notifications in L4?, Thomas Bushnell, BSG, 2001/12/20
- Re: emulating no-senders notifications in L4?, Espen Skoglund, 2001/12/21
- Re: emulating no-senders notifications in L4?, Thomas Bushnell, BSG, 2001/12/21
- Re: emulating no-senders notifications in L4?, Espen Skoglund, 2001/12/21
- Re: emulating no-senders notifications in L4?, Thomas Bushnell, BSG, 2001/12/21
- Re: emulating no-senders notifications in L4?, Ondrej Hurt, 2001/12/20
- Re: emulating no-senders notifications in L4?, Jean Wolter, 2001/12/20