Comment 17 for bug 1614382

Reviewed: https://review.opencontrail.org/23851
Committed: http://github.org/Juniper/contrail-vrouter/commit/da3c6846a905619bfe08c44521dfade1e1c958d3
Submitter: Zuul
Branch: R3.1

commit da3c6846a905619bfe08c44521dfade1e1c958d3
Author: Divakar <email address hidden>
Date: Thu Aug 18 11:17:21 2016 +0530

Hash table fixes

1) Currently the number of delete marked hash entries in Hash bucket is used
for triggering the work item for the deletion. Work item is triggered
when the first entry is delete marked. But due to contention in handling
"number of delete marked entries", the next work item is never
triggered.
As a fix, a new variable is used per hash bucket to trigger the work
item.

2) When Agent gives soft reset, Vrouter marks vr_not_ready. Once
vr_not_ready is set, Work items and RCU callbacks should not be
registered any more. In hash table deletion process, once this is set,
hash bucket is directly manipulated without work item. This results in
issues, if any pending work item is currently being executed. If work
item and hash entry deletion (vr_htable_release_hentry()) access the
same hash bucket, the hash bucket list goes bad.

As a fix, a new API vr_htable_reset() is introduced.
vr_htable_release_hentry() does not manipulate the hash entry if
vr_not_ready is setup. Modules are expected to call vr_htable_reset() to
reset the hash table. Call backs are invoked to act on the reset hash
entries.

Change-Id: I1b153d5e5579d933481b7574cd9f2e8b2410b335
closes-bug: #1614382