!16049 [MS][LITE]fix memory leak caused by unterminated threads

From: @probiotics_53
Reviewed-by: @zhang_xue_tong,@zhanghaibo5
Signed-off-by: @zhang_xue_tong

mindspore/core/mindrt/include/mindrt.hpp

@@ -33,6 +33,9 @@ struct MindrtAddress {
 int Initialize(const std::string &tcpUrl, const std::string &tcpUrlAdv = "", const std::string &udpUrl = "",
                const std::string &udpUrlAdv = "", int threadCount = 0);
 
+// brief terminate the threads for current session
+void TerminateCurThreads(int threadCount = 0);
+
 // brief spawn a process to run an actor
 AID Spawn(ActorReference actor, bool sharedThread = true, bool start = true);
 

mindspore/core/mindrt/src/actor/actormgr.cc

@@ -100,6 +100,8 @@ void ActorMgr::TerminateAll() {
 
 void ActorMgr::Initialize(int threadCount) { threadPool.AddThread(threadCount); }
 
+void ActorMgr::TerminateCurThreads(int threadCount) { threadPool.TerminateThread(threadCount); }
+
 void ActorMgr::Finalize() {
   this->TerminateAll();
   MS_LOG(INFO) << "mindrt Actors finish exiting.";

mindspore/core/mindrt/src/actor/actormgr.h

@@ -48,6 +48,7 @@ class ActorMgr {
 
   void Finalize();
   void Initialize(int threadCount);
+  void TerminateCurThreads(int threadCount);
   void RemoveActor(const std::string &name);
   ActorReference GetActor(const AID &id);
   const std::string GetUrl(const std::string &protocol = "tcp");

mindspore/core/mindrt/src/actor/actorthread.cc

@@ -59,7 +59,8 @@ ActorThread::ActorThread() : readyActors(), workers() {
 ActorThread::~ActorThread() {}
 void ActorThread::AddThread(int threadCount) {
   std::unique_lock<std::mutex> lock(initLock_);
-  for (int i = 0; i < threadCount; ++i) {
+  int threadsNeed = threadCount - (workers.size() - threadsInUse_);
+  for (int i = 0; i < threadsNeed; ++i) {
     if (workers.size() >= maxThreads_) {
       MS_LOG(DEBUG) << "threads number in mindrt reach upper limit. maxThreads:" << maxThreads_;
       break;
@@ -68,8 +69,15 @@ void ActorThread::AddThread(int threadCount) {
     MINDRT_OOM_EXIT(worker)
 
     workers.push_back(std::move(worker));
+    threadsInUse_ += 1;
   }
 }
+
+void ActorThread::TerminateThread(int threadCount) {
+  // temp scheme, not actually terminate the threads when current session destructs
+  threadsInUse_ -= threadCount;
+}
+
 void ActorThread::Finalize() {
   MS_LOG(INFO) << "Actor's threads are exiting.";
   // terminate all thread; enqueue nullptr actor to terminate;

mindspore/core/mindrt/src/actor/actorthread.h

@@ -33,6 +33,7 @@ class ActorThread {
   ~ActorThread();
   void Finalize();
   void AddThread(int threadCount);
+  void TerminateThread(int threadCount);
   void EnqueReadyActor(const std::shared_ptr<ActorBase> &actor);
 
  private:
@@ -46,6 +47,7 @@ class ActorThread {
   std::list<std::unique_ptr<std::thread>> workers;
   std::string threadName;
 
+  size_t threadsInUse_ = 0;
   size_t maxThreads_;
   std::mutex initLock_;
 };

mindspore/core/mindrt/src/mindrt.cc

@@ -59,6 +59,8 @@ const MindrtAddress &GetMindrtAddress() {
 
 void SetThreadCount(int threadCount) { ActorMgr::GetActorMgrRef()->Initialize(threadCount); }
 
+void TerminateCurThreads(int threadCount) { ActorMgr::GetActorMgrRef()->TerminateCurThreads(threadCount); }
+
 class MindrtExit {
  public:
   MindrtExit() { MS_LOG(DEBUG) << "trace: enter MindrtExit()---------"; }

mindspore/lite/src/lite_mindrt.cc

@@ -71,6 +71,7 @@ void MindrtTerminate(std::vector<std::shared_ptr<LiteOpActor>> actor_list) {
   for (auto actor : actor_list) {
     mindspore::Terminate(actor->GetAID());
   }
+  mindspore::TerminateCurThreads(1);
   return;
 }