Re: Process Management (was: Re: Reliability of RPC services)

[Jonathan S. Shapiro]

On Thu, 2006-04-27 at 21:14 +0200, Marcus Brinkmann wrote:

> Michal is right, the defining relationship between processes is the
> parent-child relationship.

This is true in the example you are discussing, and in many other
examples, but it does not generalize. In general, the defining
relationship between processes is the relationship defined by the
processes. Parent/child is only one possible relationship.


> Instead, every process will know about its child processes.  These
> child processes have local job numbers (not global process IDs)
> similar to bash's %n.  Because the resources are distributed
> hierarchically, forcibly killing a job will kill all its descendants
> as well.  This is the right thing to do.

In Coyotos, the important relationship for purpose of killing things is
the parent/child relationships of the space banks. The correct way to
kill this JVM is to kill the space bank from which it was run. This will
(recursively) kill everthing allocated from that bank, including
sub-processes. The resources do not go away because the processes die.
It is the other way around: the processes die because the resources are
revoked.


>From the user perspective the interface could look the same as the "kill
the JVM process" interface, but I wanted to make sure that there was no
confusion about the actual mechanism.


shap