Remove RPC notification from transaction in create/update port

Removing notifications to the L3 agent from within the transaction in
create_port and update_port eliminates many lock wait timeouts in the
dvr check queue job and in scale testing locally.

Since this patch leaves context unused in _process_port_binding, the
argument is removed from the method.

Closes-Bug: #1371732

Change-Id: Ibd86611ad3e7eff085d769bdff777a5870f30c58

neutron/plugins/ml2/plugin.py

@@ -159,7 +159,27 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
         # TODO(rkukura): Implement filtering.
         return nets
 
-    def _process_port_binding(self, mech_context, context, attrs):
+    def _notify_l3_agent_new_port(self, context, port):
+        if not port:
+            return
+
+        # Whenever a DVR serviceable port comes up on a
+        # node, it has to be communicated to the L3 Plugin
+        # and agent for creating the respective namespaces.
+        if (utils.is_dvr_serviced(port['device_owner'])):
+            l3plugin = manager.NeutronManager.get_service_plugins().get(
+                service_constants.L3_ROUTER_NAT)
+            if (utils.is_extension_supported(
+                l3plugin, const.L3_DISTRIBUTED_EXT_ALIAS)):
+                l3plugin.dvr_update_router_addvm(context, port)
+
+    def _get_host_port_if_changed(self, mech_context, attrs):
+        binding = mech_context._binding
+        host = attrs and attrs.get(portbindings.HOST_ID)
+        if (attributes.is_attr_set(host) and binding.host != host):
+            return mech_context.current
+
+    def _process_port_binding(self, mech_context, attrs):
         binding = mech_context._binding
         port = mech_context.current
         changes = False
@@ -169,15 +189,6 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
             binding.host != host):
             binding.host = host
             changes = True
-            # Whenever a DVR serviceable port comes up on a
-            # node, it has to be communicated to the L3 Plugin
-            # and agent for creating the respective namespaces.
-            if (utils.is_dvr_serviced(port['device_owner'])):
-                l3plugin = manager.NeutronManager.get_service_plugins().get(
-                    service_constants.L3_ROUTER_NAT)
-                if (utils.is_extension_supported(
-                    l3plugin, const.L3_DISTRIBUTED_EXT_ALIAS)):
-                    l3plugin.dvr_update_router_addvm(context, port)
 
         vnic_type = attrs and attrs.get(portbindings.VNIC_TYPE)
         if (attributes.is_attr_set(vnic_type) and
@@ -770,7 +781,8 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
             binding = db.add_port_binding(session, result['id'])
             mech_context = driver_context.PortContext(self, context, result,
                                                       network, binding)
-            self._process_port_binding(mech_context, context, attrs)
+            new_host_port = self._get_host_port_if_changed(mech_context, attrs)
+            self._process_port_binding(mech_context, attrs)
 
             result[addr_pair.ADDRESS_PAIRS] = (
                 self._process_create_allowed_address_pairs(
@@ -780,6 +792,9 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                                                       dhcp_opts)
             self.mechanism_manager.create_port_precommit(mech_context)
 
+        # Notification must be sent after the above transaction is complete
+        self._notify_l3_agent_new_port(context, new_host_port)
+
         try:
             self.mechanism_manager.create_port_postcommit(mech_context)
         except ml2_exc.MechanismDriverError:
@@ -834,10 +849,14 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
             mech_context = driver_context.PortContext(
                 self, context, updated_port, network, binding,
                 original_port=original_port)
+            new_host_port = self._get_host_port_if_changed(mech_context, attrs)
             need_port_update_notify |= self._process_port_binding(
-                mech_context, context, attrs)
+                mech_context, attrs)
             self.mechanism_manager.update_port_precommit(mech_context)
 
+        # Notification must be sent after the above transaction is complete
+        self._notify_l3_agent_new_port(context, new_host_port)
+
         # TODO(apech) - handle errors raised by update_port, potentially
         # by re-calling update_port with the previous attributes. For
         # now the error is propogated to the caller, which is expected to

neutron/tests/unit/ml2/test_ml2_plugin.py

@@ -23,6 +23,7 @@ from neutron.common import constants
 from neutron.common import exceptions as exc
 from neutron.common import utils
 from neutron import context
+from neutron.db import db_base_plugin_v2 as base_plugin
 from neutron.extensions import multiprovidernet as mpnet
 from neutron.extensions import portbindings
 from neutron.extensions import providernet as pnet
@@ -36,6 +37,7 @@ from neutron.plugins.ml2 import driver_context
 from neutron.plugins.ml2.drivers import type_vlan
 from neutron.plugins.ml2 import models
 from neutron.plugins.ml2 import plugin as ml2_plugin
+from neutron.tests import base
 from neutron.tests.unit import _test_extension_portbindings as test_bindings
 from neutron.tests.unit.ml2.drivers import mechanism_logger as mech_logger
 from neutron.tests.unit.ml2.drivers import mechanism_test as mech_test
@@ -940,3 +942,60 @@ class TestFaultyMechansimDriver(Ml2PluginV2FaultyDriverTestCase):
                     self.assertEqual(new_name, port['port']['name'])
 
                     self._delete('ports', port['port']['id'])
+
+
+class TestMl2PluginCreateUpdatePort(base.BaseTestCase):
+    def setUp(self):
+        super(TestMl2PluginCreateUpdatePort, self).setUp()
+        self.context = mock.MagicMock()
+
+    def _ensure_transaction_is_closed(self):
+        transaction = self.context.session.begin(subtransactions=True)
+        enter = transaction.__enter__.call_count
+        exit = transaction.__exit__.call_count
+        self.assertEqual(enter, exit)
+
+    def _create_plugin_for_create_update_port(self, new_host_port):
+        plugin = ml2_plugin.Ml2Plugin()
+        plugin.extension_manager = mock.Mock()
+        plugin.type_manager = mock.Mock()
+        plugin.mechanism_manager = mock.Mock()
+        plugin.notifier = mock.Mock()
+        plugin._get_host_port_if_changed = mock.Mock(
+            return_value=new_host_port)
+
+        plugin._notify_l3_agent_new_port = mock.Mock()
+        plugin._notify_l3_agent_new_port.side_effect = (
+            lambda c, p: self._ensure_transaction_is_closed())
+
+        return plugin
+
+    def test_create_port_rpc_outside_transaction(self):
+        with contextlib.nested(
+            mock.patch.object(ml2_plugin.Ml2Plugin, '__init__'),
+            mock.patch.object(base_plugin.NeutronDbPluginV2, 'create_port'),
+        ) as (init, super_create_port):
+            init.return_value = None
+
+            new_host_port = mock.Mock()
+            plugin = self._create_plugin_for_create_update_port(new_host_port)
+
+            plugin.create_port(self.context, mock.MagicMock())
+
+            plugin._notify_l3_agent_new_port.assert_called_once_with(
+                self.context, new_host_port)
+
+    def test_update_port_rpc_outside_transaction(self):
+        with contextlib.nested(
+            mock.patch.object(ml2_plugin.Ml2Plugin, '__init__'),
+            mock.patch.object(base_plugin.NeutronDbPluginV2, 'update_port'),
+        ) as (init, super_update_port):
+            init.return_value = None
+
+            new_host_port = mock.Mock()
+            plugin = self._create_plugin_for_create_update_port(new_host_port)
+
+            plugin.update_port(self.context, 'fake_id', mock.MagicMock())
+
+            plugin._notify_l3_agent_new_port.assert_called_once_with(
+                self.context, new_host_port)