Comment 15 for bug 1481606

Reviewed: https://review.opencontrail.org/14314
Committed: http://github.org/Juniper/contrail-vrouter/commit/a075b88ce69fa9c2209a119b6a8f2e0c7eaaa167
Submitter: Zuul
Branch: R2.20

commit a075b88ce69fa9c2209a119b6a8f2e0c7eaaa167
Author: Divakar <email address hidden>
Date: Wed Aug 26 17:23:53 2015 +0530

Bridge table overflow table restructuring

As of now, bridge table overflow table is searched every time there is a
bridge miss in the main table. The search of overflow table is a sweep
of all entries starting from bridge key's hash value. In an unknown
unicast scenario, for every packet, the complete overflow table is swept
to identify that it is an unknown unicast. This is resulting in
performance degradation.

So it is now restructured in such a way that from main table bucket,
there is a list of overflow entries corresponding only to
that bucket. This list is a singly linked list from the last entry of
bucket in main table. There is a bitmap of free over flow entries
maintained to allocate a new over flow entry when ever required.

Change-Id: I92e1ddfeb7837847ba11940ba06c0e201150f2f7
closes-bug: #1481606