[Java] Release actor instance reference when Ray.exitActor() is invoked (#11324)

java/runtime/src/main/java/io/ray/runtime/AbstractRayRuntime.java

@@ -282,6 +282,11 @@ public abstract class AbstractRayRuntime implements RayRuntimeInternal {
     return objectStore;
   }
 
+  @Override
+  public TaskExecutor getTaskExecutor() {
+    return taskExecutor;
+  }
+
   @Override
   public FunctionManager getFunctionManager() {
     return functionManager;

java/runtime/src/main/java/io/ray/runtime/RayRuntimeInternal.java

@@ -6,6 +6,7 @@ import io.ray.runtime.context.WorkerContext;
 import io.ray.runtime.functionmanager.FunctionManager;
 import io.ray.runtime.gcs.GcsClient;
 import io.ray.runtime.object.ObjectStore;
+import io.ray.runtime.task.TaskExecutor;
 
 /**
  * This interface is required to make {@link RayRuntimeProxy} work.
@@ -21,6 +22,8 @@ public interface RayRuntimeInternal extends RayRuntime {
 
   ObjectStore getObjectStore();
 
+  TaskExecutor getTaskExecutor();
+
   FunctionManager getFunctionManager();
 
   RayConfig getRayConfig();

java/runtime/src/main/java/io/ray/runtime/task/NativeTaskExecutor.java

@@ -45,6 +45,11 @@ public class NativeTaskExecutor extends TaskExecutor<NativeTaskExecutor.NativeAc
     return new NativeActorContext();
   }
 
+  public void onWorkerShutdown(byte[] workerIdBytes) {
+    // This is to make sure no memory leak when `Ray.exitActor()` is called.
+    removeActorContext(new UniqueId(workerIdBytes));
+  }
+
   @Override
   protected void maybeSaveCheckpoint(Object actor, ActorId actorId) {
     if (!(actor instanceof Checkpointable)) {

java/runtime/src/main/java/io/ray/runtime/task/TaskExecutor.java

@@ -65,6 +65,10 @@ public abstract class TaskExecutor<T extends TaskExecutor.ActorContext> {
     this.actorContextMap.put(runtime.getWorkerContext().getCurrentWorkerId(), actorContext);
   }
 
+  protected void removeActorContext(UniqueId workerId) {
+    this.actorContextMap.remove(workerId);
+  }
+
   private RayFunction getRayFunction(List<String> rayFunctionInfo) {
     JobId jobId = runtime.getWorkerContext().getCurrentJobId();
     JavaFunctionDescriptor functionDescriptor = parseFunctionDescriptor(rayFunctionInfo);

java/test/src/main/java/io/ray/test/ExitActorTest.java

@@ -9,9 +9,12 @@ import io.ray.api.Ray;
 import io.ray.api.id.ActorId;
 import io.ray.api.id.UniqueId;
 import io.ray.runtime.exception.RayActorException;
+import io.ray.runtime.task.TaskExecutor;
 import io.ray.runtime.util.SystemUtil;
 import java.io.IOException;
+import java.lang.reflect.Field;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import org.testng.Assert;
 import org.testng.annotations.Test;
@@ -31,6 +34,17 @@ public class ExitActorTest extends BaseTest {
       return pid();
     }
 
+    public int getSizeOfActorContextMap() {
+      TaskExecutor taskExecutor = TestUtils.getRuntime().getTaskExecutor();
+      try {
+        Field field = TaskExecutor.class.getDeclaredField("actorContextMap");
+        field.setAccessible(true);
+        return ((Map<?, ?>)field.get(taskExecutor)).size();
+      } catch (Exception e) {
+        throw new RuntimeException(e);
+      }
+    }
+
     @Override
     public boolean shouldCheckpoint(CheckpointContext checkpointContext) {
       return true;
@@ -77,6 +91,8 @@ public class ExitActorTest extends BaseTest {
     ActorHandle<ExitingActor> actor1 = Ray.actor(ExitingActor::new)
         .setMaxRestarts(10000).remote();
     int pid = actor1.task(ExitingActor::getPid).remote().get();
+    Assert.assertEquals(
+        1, (int) actor1.task(ExitingActor::getSizeOfActorContextMap).remote().get());
     ActorHandle<ExitingActor> actor2;
     while (true) {
       // Create another actor which share the same process of actor 1.
@@ -86,11 +102,17 @@ public class ExitActorTest extends BaseTest {
         break;
       }
     }
+    Assert.assertEquals(
+        2, (int) actor1.task(ExitingActor::getSizeOfActorContextMap).remote().get());
+    Assert.assertEquals(
+        2, (int) actor2.task(ExitingActor::getSizeOfActorContextMap).remote().get());
     ObjectRef<Boolean> obj1 = actor1.task(ExitingActor::exit).remote();
     Assert.assertThrows(RayActorException.class, obj1::get);
     Assert.assertTrue(SystemUtil.isProcessAlive(pid));
     // Actor 2 shouldn't exit or be reconstructed.
     Assert.assertEquals(1, (int) actor2.task(ExitingActor::incr).remote().get());
+    Assert.assertEquals(
+        1, (int) actor2.task(ExitingActor::getSizeOfActorContextMap).remote().get());
     Assert.assertEquals(pid, (int) actor2.task(ExitingActor::getPid).remote().get());
     Assert.assertTrue(SystemUtil.isProcessAlive(pid));
   }

python/ray/includes/libcoreworker.pxd

@@ -19,6 +19,7 @@ from ray.includes.unique_ids cimport (
     CTaskID,
     CObjectID,
     CPlacementGroupID,
+    CWorkerID,
 )
 from ray.includes.common cimport (
     CAddress,
@@ -227,6 +228,7 @@ cdef extern from "ray/core_worker/core_worker.h" nogil:
             const c_vector[CObjectID] &return_ids,
             c_vector[shared_ptr[CRayObject]] *returns) nogil
          ) task_execution_callback
+        (void(const CWorkerID &) nogil) on_worker_shutdown
         (CRayStatus() nogil) check_signals
         (void() nogil) gc_collect
         (c_vector[c_string](const c_vector[CObjectID]&) nogil) spill_objects

src/ray/core_worker/core_worker.cc

@@ -541,6 +541,9 @@ void CoreWorker::Shutdown() {
   if (options_.worker_type == WorkerType::WORKER) {
     task_execution_service_.stop();
   }
+  if (options_.on_worker_shutdown) {
+    options_.on_worker_shutdown(GetWorkerID());
+  }
 }
 
 void CoreWorker::Disconnect() {

src/ray/core_worker/core_worker.h

@@ -123,6 +123,8 @@ struct CoreWorkerOptions {
   std::string stderr_file;
   /// Language worker callback to execute tasks.
   TaskExecutionCallback task_execution_callback;
+  /// The callback to be called when shutting down a `CoreWorker` instance.
+  std::function<void(const WorkerID &)> on_worker_shutdown;
   /// Application-language callback to check for signals that have been received
   /// since calling into C++. This will be called periodically (at least every
   /// 1s) during long-running operations. If the function returns anything but StatusOK,

src/ray/core_worker/lib/java/io_ray_runtime_RayNativeRuntime.cc

@@ -150,6 +150,7 @@ JNIEXPORT void JNICALL Java_io_ray_runtime_RayNativeRuntime_nativeInitialize(
         if (throwable &&
             env->IsInstanceOf(throwable,
                               java_ray_intentional_system_exit_exception_class)) {
+          env->ExceptionClear();
           return ray::Status::IntentionalSystemExit();
         }
         RAY_CHECK_JAVA_EXCEPTION(env);
@@ -211,6 +212,16 @@ JNIEXPORT void JNICALL Java_io_ray_runtime_RayNativeRuntime_nativeInitialize(
     }
   };
 
+  auto on_worker_shutdown = [](const ray::WorkerID &worker_id) {
+    JNIEnv *env = GetJNIEnv();
+    auto worker_id_bytes = IdToJavaByteArray<ray::WorkerID>(env, worker_id);
+    if (java_task_executor) {
+      env->CallVoidMethod(java_task_executor,
+                          java_native_task_executor_on_worker_shutdown, worker_id_bytes);
+      RAY_CHECK_JAVA_EXCEPTION(env);
+    }
+  };
+
   std::string serialized_job_config =
       (jobConfig == nullptr ? "" : JavaByteArrayToNativeString(env, jobConfig));
   ray::CoreWorkerOptions options;
@@ -229,6 +240,7 @@ JNIEXPORT void JNICALL Java_io_ray_runtime_RayNativeRuntime_nativeInitialize(
   options.raylet_ip_address = JavaStringToNativeString(env, nodeIpAddress);
   options.driver_name = JavaStringToNativeString(env, driverName);
   options.task_execution_callback = task_execution_callback;
+  options.on_worker_shutdown = on_worker_shutdown;
   options.gc_collect = gc_collect;
   options.ref_counting_enabled = true;
   options.num_workers = static_cast<int>(numWorkersPerProcess);

src/ray/core_worker/lib/java/jni_init.cc

@@ -107,6 +107,9 @@ jclass java_task_executor_class;
 jmethodID java_task_executor_parse_function_arguments;
 jmethodID java_task_executor_execute;
 
+jclass java_native_task_executor_class;
+jmethodID java_native_task_executor_on_worker_shutdown;
+
 jclass java_placement_group_class;
 jfieldID java_placement_group_id;
 
@@ -267,6 +270,10 @@ jint JNI_OnLoad(JavaVM *vm, void *reserved) {
   java_task_executor_execute =
       env->GetMethodID(java_task_executor_class, "execute",
                        "(Ljava/util/List;Ljava/util/List;)Ljava/util/List;");
+  java_native_task_executor_class =
+      LoadClass(env, "io/ray/runtime/task/NativeTaskExecutor");
+  java_native_task_executor_on_worker_shutdown =
+      env->GetMethodID(java_native_task_executor_class, "onWorkerShutdown", "([B)V");
   return CURRENT_JNI_VERSION;
 }
 
@@ -298,4 +305,5 @@ void JNI_OnUnload(JavaVM *vm, void *reserved) {
   env->DeleteGlobalRef(java_actor_creation_options_class);
   env->DeleteGlobalRef(java_native_ray_object_class);
   env->DeleteGlobalRef(java_task_executor_class);
+  env->DeleteGlobalRef(java_native_task_executor_class);
 }

src/ray/core_worker/lib/java/jni_utils.h

@@ -187,6 +187,11 @@ extern jmethodID java_task_executor_parse_function_arguments;
 /// execute method of TaskExecutor class
 extern jmethodID java_task_executor_execute;
 
+/// NativeTaskExecutor class
+extern jclass java_native_task_executor_class;
+/// onWorkerShutdown method of NativeTaskExecutor class
+extern jmethodID java_native_task_executor_on_worker_shutdown;
+
 /// PlacementGroup class
 extern jclass java_placement_group_class;
 /// id field of PlacementGroup class