fixes:
  - |
    `Bug #2091033`_: Fixed calls to libvirt ``listDevices()`` and
    ``listAllDevices()`` from potentially blocking all other greenthreads
    in ``nova-compute``. Under certain circumstances, it was possible for
    the ``nova-compute`` service to freeze with all other greenthreads
    blocked and unable to perform any other activities including logging.
    This issue has been fixed by wrapping the libvirt ``listDevices()``
    and ``listAllDevices()`` calls with ``eventlet.tpool.Proxy``.

    .. _Bug #2091033: https://bugs.launchpad.net/nova/+bug/2091033
