Allow actors to pin at most 1000 dummy objects at a time. (#1241)

* Allow actors to pin at most 1000 dummy objects at a time.

* Fix linting.

python/ray/actor.py

@@ -134,7 +134,10 @@ def put_dummy_object(worker, dummy_object_id):
     # actor, to prevent eviction from the object store.
     dummy_object = worker.get_object([dummy_object_id])
     dummy_object = dummy_object[0]
-    worker.actor_pinned_objects[dummy_object_id] = dummy_object
+    worker.actor_pinned_objects.append(dummy_object)
+    if (len(worker.actor_pinned_objects) >
+            ray._config.actor_max_dummy_objects()):
+        worker.actor_pinned_objects.pop(0)
 
 
 def make_actor_method_executor(worker, method_name, method):

python/ray/worker.py

@@ -1836,7 +1836,7 @@ def connect(info, object_id_seed=None, mode=WORKER_MODE, worker=global_worker,
         worker.class_id = class_id
         # Store a list of the dummy outputs produced by actor tasks, to pin the
         # dummy outputs in the object store.
-        worker.actor_pinned_objects = {}
+        worker.actor_pinned_objects = []
 
     # Initialize the serialization library. This registers some classes, and so
     # it must be run before we export all of the cached remote functions.

src/common/lib/python/config_extension.cc

@@ -35,6 +35,10 @@ PyObject *PyRayConfig_worker_fetch_request_size(PyObject *self) {
   return PyLong_FromLongLong(RayConfig::instance().worker_fetch_request_size());
 }
 
+PyObject *PyRayConfig_actor_max_dummy_objects(PyObject *self) {
+  return PyLong_FromLongLong(RayConfig::instance().actor_max_dummy_objects());
+}
+
 PyObject *PyRayConfig_num_connect_attempts(PyObject *self) {
   return PyLong_FromLongLong(RayConfig::instance().num_connect_attempts());
 }
@@ -145,6 +149,9 @@ static PyMethodDef PyRayConfig_methods[] = {
     {"worker_fetch_request_size",
      (PyCFunction) PyRayConfig_worker_fetch_request_size, METH_NOARGS,
      "Return worker_fetch_request_size"},
+    {"actor_max_dummy_objects",
+     (PyCFunction) PyRayConfig_actor_max_dummy_objects, METH_NOARGS,
+     "Return actor_max_dummy_objects"},
     {"num_connect_attempts", (PyCFunction) PyRayConfig_num_connect_attempts,
      METH_NOARGS, "Return num_connect_attempts"},
     {"connect_timeout_milliseconds",

src/common/lib/python/config_extension.h

@@ -22,6 +22,7 @@ PyObject *PyRayConfig_num_heartbeats_timeout(PyObject *self);
 PyObject *PyRayConfig_get_timeout_milliseconds(PyObject *self);
 PyObject *PyRayConfig_worker_get_request_size(PyObject *self);
 PyObject *PyRayConfig_worker_fetch_request_size(PyObject *self);
+PyObject *PyRayConfig_actor_max_dummy_objects(PyObject *self);
 PyObject *PyRayConfig_num_connect_attempts(PyObject *self);
 PyObject *PyRayConfig_connect_timeout_milliseconds(PyObject *self);
 PyObject *PyRayConfig_local_scheduler_fetch_timeout_milliseconds(

src/common/state/ray_config.h

@@ -27,6 +27,8 @@ class RayConfig {
     return worker_fetch_request_size_;
   }
 
+  int64_t actor_max_dummy_objects() const { return actor_max_dummy_objects_; }
+
   int64_t num_connect_attempts() const { return num_connect_attempts_; }
 
   int64_t connect_timeout_milliseconds() const {
@@ -95,6 +97,7 @@ class RayConfig {
         get_timeout_milliseconds_(1000),
         worker_get_request_size_(10000),
         worker_fetch_request_size_(10000),
+        actor_max_dummy_objects_(1000),
         num_connect_attempts_(50),
         connect_timeout_milliseconds_(100),
         local_scheduler_fetch_timeout_milliseconds_(1000),
@@ -135,6 +138,10 @@ class RayConfig {
   int64_t worker_get_request_size_;
   int64_t worker_fetch_request_size_;
 
+  /// This is a temporary constant used by actors to determine how many dummy
+  /// objects to store.
+  int64_t actor_max_dummy_objects_;
+
   /// Number of times we try connecting to a socket.
   int64_t num_connect_attempts_;
   int64_t connect_timeout_milliseconds_;