Comment 4 for bug 1813253

Reviewed: https://review.openstack.org/633406
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=1746d7e0e682eab1001bfc434b73efb1cdf5f0f4
Submitter: Zuul
Branch: master

commit 1746d7e0e682eab1001bfc434b73efb1cdf5f0f4
Author: liuchengqian90 <xieling1990.happy@163.com>
Date: Sun Jan 27 20:47:50 2019 +0800

    Update the processing of assigned addresses when assigning addresses

    1.It is best not to use 'netaddr.IPSet.add',
      because _compact_single_network in 'IPSet.add' is quite time consuming

    2.When the current address pool does not have enough addresses,
      all addresses are allocated from the current pool,
      and allocations are continued from the next address pool
      until all addresses are assigned.

    Change-Id: I804a95fdaa3552c785e85ffab7b8ac849c634a87
    Closes-Bug: #1813253