fix server shutdown

paddle/fluid/operators/detail/grpc_server.cc

@@ -174,13 +174,13 @@ void AsyncGRPCServer::ShutdownQueue() {
   std::unique_lock<std::mutex> lock(cq_mutex_);
   cq_send_->Shutdown();
   cq_get_->Shutdown();
-  is_shut_down_ = true;
 }
 
 // This URL explains why shutdown is complicate:
 void AsyncGRPCServer::ShutDown() {
-  server_->Shutdown();
+  is_shut_down_ = true;
   ShutdownQueue();
+  server_->Shutdown();
 }
 
 void AsyncGRPCServer::TryToRegisterNewSendOne() {
@@ -213,14 +213,14 @@ void AsyncGRPCServer::HandleRequest(::grpc::ServerCompletionQueue* cq,
   bool ok = false;
   while (true) {
     if (!cq->Next(&tag, &ok)) {
-      LOG(INFO) << cq_name << " get CompletionQueue shutdown!";
+      LOG(INFO) << cq_name << " CompletionQueue shutdown!";
       break;
     }
 
     PADDLE_ENFORCE(tag);
     // FIXME(typhoonzero): de-couple the barriers with recv_op
-    if (cq_name == "cq_get") WaitCond(1);
-    if (cq_name == "cq_send") WaitCond(0);
+    if (!is_shut_down_ && cq_name == "cq_get") WaitCond(1);
+    if (!is_shut_down_ && cq_name == "cq_send") WaitCond(0);
 
     RequestBase* base = (RequestBase*)tag;
     // reference:

paddle/fluid/operators/listen_and_serv_op.cc

@@ -70,7 +70,6 @@ class ListenAndServOp : public framework::OperatorBase {
 
   void Stop() override {
     rpc_service_->Push(LISTEN_TERMINATE_MESSAGE);
-    rpc_service_->ShutDown();
     server_thread_->join();
   }