libvirt: Instance NUMA fitting code fails to account for vpu_pin_set config option properly

[Nikola Đipanov]

Looking at this branch of the NUMA fitting code

https://github.com/openstack/nova/blob/51de439a4d1fe5e17d59d3aac3fd2c49556e641b/nova/virt/libvirt/driver.py#L3738

We do not account for allowed cpus when choosing viable cells for the given instance. meaning we could chose a NUMA cell that has no viable CPUs which we will try to pin to.

We need to consider allowed_cpus when calculating viable NUMA cells for the instance.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/123725

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/123790

[OpenStack Infra (hudson-openstack)]

Change abandoned by boden (<email address hidden>) on branch: master
Review: https://review.openstack.org/123790
Reason: addressed via https://review.openstack.org/#/c/123725/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/123725
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=b5df50076239adb9a5a1ef8559d32e46ad9414ae
Submitter: Jenkins
Branch: master

commit b5df50076239adb9a5a1ef8559d32e46ad9414ae
Author: Nikola Dipanov <email address hidden>
Date: Wed Sep 24 14:59:53 2014 +0200

    libvirt: consider vcpu_pin_set when choosing NUMA cells

    When we get a single NUMA cell instance scheduled to a NUMA capable
    host, we do not account for cpu_pin_set when choosing viable cells for
    the given instance. meaning we could choose a NUMA cell that has no
    viable CPUs which we will try to pin to.

    This patch changes that behaviour and also adds a test to prevent a
    regression. We also fix up how some of the tests mock the random.choice
    method, because now we give it a list of sets (of cpus), but also
    because it is now easier to catch a regression since we actually use the
    passed value.

    Change-Id: I0d740170db52a4777924648683ac98de9cf4b3cf
    Closes-bug: 1372845