Re: Persistent object handles

[Niels Möller]

Ludovic Courtès <address@hidden> writes:

> The problem is that thread ids are system-wide identifiers, ie. absolute
> references.  It would not be a problem if every single thread in the system
> was persistent and if it could be restarted using the same id (which, I
> think, is possible).  However, not every thread in the system could be
> persistent because (1) there are some task that cannot be made persistent
> anyway (eg. drivers) and (2) we might want to choose to just have a few
> persistent tasks in the system.

How big are the L4 tread id:s? Would it work to partion the
version-number space into two parts (using one bit of it), and use
that to identify persistent threads?

Ideally, you'd prefer that the communication partners of a thread not
need to know if the thread they're talking to is persstent or not. If
you need some extra level of redirection for persistent threads, that
might not be possible.

Hmm. Or you could have each persistent thread have a non-persistent
proxy. All non-persistent threads would only need to know the proxy.
Persistent threads/tasks would need some mechanism to locate each other and
to create proxies at system startup, but non-persistent tasks need not
know anything about that.

/Niels