Re: object management and IPC a bit more formal

[Ludovic Courtès]

Hi,

On Mon, May 05, 2003 at 08:36:30PM +0200, Marcus Brinkmann wrote:
> User side
> ---------
> 
> struct user_object
> {
>   thread_t server;
>   object_id_t oid;
> };

I'm a bit confused and it is still unclear to me how we could deal with
persistent tasks (clients) holding such user_objects.  IIRC, thread IDs
would contain both the PID and the subsystem ID.  PIDs are
subsystem-wide unique IDs and subsystem IDs are system-wide unique IDs.

This means that each set of persistent tasks needs to have its own
subsystem and that this subsystem ID *must not* be reused by anybody else.
This way, if the 'server' field refers to another persistent task within
the same subsystem, it would ensure that it will still be valid after
restarting the subsystem.  Is this correct?

However, if the above is correct, there are still two issues left:
 - how do we make sure that a subsystem ID can only be reused by the
   given persistent subsystem?
 - subsystem IDs are quite small on 32-bit machines.

Thanks,
Ludovic.