Comment 29 for bug 1234857

Reviewed: https://review.openstack.org/102329
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=478f4871fff9b2e3d5754ad43165b0356e07c58f
Submitter: Jenkins
Branch: stable/icehouse

commit 478f4871fff9b2e3d5754ad43165b0356e07c58f
Author: Maru Newby <email address hidden>
Date: Wed May 7 22:41:40 2014 +0000

    Ensure core plugin deallocation after every test

    The unit tests were previously consuming an excessive amount of memory
    (4GB+) due to plugin instances persisting in memory. Deallocation was
    not possible where a combination of circular references and mocking
    was involved. This patch ensures that only NeutronManager holds a
    plugin reference and that all other references are instances of
    weakref.proxy. Residual memory footprint for tox executed on a
    12-core machine has been reduced to ~1.3GB. Plugin deallocation is
    validated at the end of each test to prevent regressions.

    This change also includes fixes to unit tests that depended on plugin
    instances persisting across tests.

    Conflicts:

     neutron/tests/base.py
     neutron/tests/unit/ml2/test_mechanism_odl.py
     neutron/tests/unit/test_db_plugin.py

    Partial-Bug: #1234857
    Change-Id: Ia1f868c2d206eb72ef77d290d054f3c48ab58c94
    (cherry picked from commit 6db48dd688d45ba41863926fa1a91d2d3ea484ec)