[Devel] Re: [PATCH v7 09/10] IPC: message queue copy feature introduced

[Eric W. Biederman]

Stanislav Kinsbursky <skinsbursky at parallels.com> writes:

> It's not just an optimisation.
> If crtools will fail (with SIGSEGV, for instance), then queue will be empty.

Regardless of what you call the benefit of this enhancement, this
enhancement is not required to implement checkpoint/restart.

For reliability/restartability I suspect a simple enqueue/dequeue loop
over each message in the queue would be nearly as proof against SIGSEGV
and other failures.

So since all of these changes are enhancements we need to know what we
are getting, over just sticking with the existing interfaces.

Unless there is a real bottleneck for something to work, I suspect the
direction forward is to make checkpoint and restart work with the
existing kernel interfaces and then revisit that decision when you
actually have a real problem.

Eric