MS-611 Add resources validity check in ResourceMgr

Former-commit-id: 0957d8980a07a07434bc2bea3ecff686a56cb127

cpp/src/scheduler/ResourceMgr.cpp

@@ -104,6 +104,10 @@ ResourceMgr::Connect(const std::string& name1, const std::string& name2, Connect
 void
 ResourceMgr::Clear() {
     std::lock_guard<std::mutex> lck(resources_mutex_);
+    if (running_) {
+        ENGINE_LOG_ERROR << "ResourceMgr is running, cannot clear.";
+        return;
+    }
     disk_resources_.clear();
     cpu_resources_.clear();
     gpu_resources_.clear();

cpp/src/scheduler/task/SearchTask.cpp

@@ -34,6 +34,7 @@ static constexpr size_t PARALLEL_REDUCE_BATCH = 1000;
 
 std::mutex XSearchTask::merge_mutex_;
 
+// TODO(wxyu): remove unused code
 // bool
 // NeedParallelReduce(uint64_t nq, uint64_t topk) {
 //    server::ServerConfig &config = server::ServerConfig::GetInstance();