RFR: 8241423: NUMA APIs may fail to work in the docker due to operation not permitted

[Florian Weimer]

* Bob Vandette:

> I understand but it would be useful to ensure that all aspects of
> supporting NUMA in containers work while addressing this issue.
> What good is it to enable NUMA but have it not work properly.  I’m
> only asking for some validation since you appear to have a proper
> setup.

There is a large variability among container environments, so this
seems rather futile.

> It would be better if we could find a more supported way of
> determining if our process has the required access rather than
> counting on a failing syscall.
>
> What about using prctl?
>
> http://man7.org/linux/man-pages/man2/prctl.2.html
>
> This call can be used to query if a specific capability is enabled.

I think the only feasible way would be to probe early if all the
required system calls (and flag arguments) are available.  Container
environments block prctl operations, too, or block system calls by
completely different means (such as a patched Linux kernel).

It may be more attractive to ask container environments to provide a
closer approximation to the official Linux system call interface.