Instance manager task queue size

1) To insert the Instnace task into task queue, hash of service instance
uuid is used. To identify the numer of task queues avaialble,
.capacity() routine is used on vector, whose value mgiht be more than
the size of the vector. If task is inserted into a vector position
that is more than the size of vector, exception can occur. To avoid
this, .size() routine is invoked.

2) While inserting the task into the map of (service instance, task),
strict error check is made to ensure that we dont insert the same task
again into the map.

3) While starting the task, if there is an error, task is removed from
above map without unregistering the service instance, which might lead
to wrong refcounting. To avaoid this, unregisterserviceinstane() is
invoked which takes care of refcounting.

Change-Id: I1608be4f47d3a981aa1f8b7c9f48e0e80d21fc33
partial-bug: #1462042

src/vnsw/agent/oper/instance_manager.cc

@@ -409,7 +409,7 @@ void InstanceManager::Enqueue(InstanceTask *task,
 
 InstanceTaskQueue *InstanceManager::GetTaskQueue(const std::string &str) {
     boost::hash<std::string> hash;
-    int index = hash(str) % task_queues_.capacity();
+    int index = hash(str) % task_queues_.size();
     return task_queues_[index];
 }
 
@@ -438,7 +438,7 @@ bool InstanceManager::StartTask(InstanceTaskQueue *task_queue,
     }
 
     task_queue->Pop();
-    task_svc_instances_.erase(task);
+    UnregisterSvcInstance(task);
     delete task;
 
     return false;
@@ -488,7 +488,7 @@ void InstanceManager::ScheduleNextTask(InstanceTaskQueue *task_queue) {
 }
 
 ServiceInstance *InstanceManager::GetSvcInstance(InstanceTask *task) const {
-    std::map<InstanceTask *, ServiceInstance*>::const_iterator iter =
+    TaskSvcMap::const_iterator iter =
                     task_svc_instances_.find(task);
     if (iter != task_svc_instances_.end()) {
         return iter->second;
@@ -498,14 +498,17 @@ ServiceInstance *InstanceManager::GetSvcInstance(InstanceTask *task) const {
 
 void InstanceManager::RegisterSvcInstance(InstanceTask *task,
                                           ServiceInstance *svc_instance) {
-    task_svc_instances_.insert(std::make_pair(task, svc_instance));
+    pair<TaskSvcMap::iterator, bool> result =
+               task_svc_instances_.insert(std::make_pair(task, svc_instance));
+    assert(result.second);
+
     InstanceState *state = GetState(svc_instance);
     assert(state);
     state->incr_tasks_running();
 }
 
 ServiceInstance *InstanceManager::UnregisterSvcInstance(InstanceTask *task) {
-    for (std::map<InstanceTask *, ServiceInstance*>::iterator iter =
+    for (TaskSvcMap::iterator iter =
                     task_svc_instances_.begin();
          iter != task_svc_instances_.end(); ++iter) {
         if (task == iter->first) {
@@ -526,8 +529,7 @@ void InstanceManager::UnregisterSvcInstance(ServiceInstance *svc_instance) {
     InstanceState *state = GetState(svc_instance);
     assert(state);
 
-    std::map<InstanceTask *, ServiceInstance*>::iterator iter =
-        task_svc_instances_.begin();
+    TaskSvcMap::iterator iter = task_svc_instances_.begin();
     while(iter != task_svc_instances_.end()) {
         if (svc_instance == iter->second) {
             task_svc_instances_.erase(iter++);

src/vnsw/agent/oper/instance_manager.h

@@ -145,7 +145,8 @@ class InstanceManager {
     WorkQueue<InstanceManagerChildEvent> work_queue_;
 
     std::vector<InstanceTaskQueue *> task_queues_;
-    std::map<InstanceTask *, ServiceInstance *> task_svc_instances_;
+    typedef std::map<InstanceTask *, ServiceInstance *> TaskSvcMap;
+    TaskSvcMap task_svc_instances_;
     std::map<std::string, int> last_cmd_types_;
     std::string loadbalancer_config_path_;
     std::string namespace_store_path_;