Treat actor creation like a regular task. (#1668)

* Treat actor creation like a regular task.

* Small cleanups.

* Change semantics of actor resource handling.

* Bug fix.

* Minor linting

* Bug fix

* Fix jenkins test.

* Fix actor tests

* Some cleanups

* Bug fix

* Fix bug.

* Remove cached actor tasks when a driver is removed.

* Add more info to taskspec in global state API.

* Fix cyclic import bug in tune.

* Fix

* Fix linting.

* Fix linting.

* Don't schedule any tasks (especially actor creaiton tasks) on local schedulers with 0 CPUs.

* Bug fix.

* Add test for 0 CPU case

* Fix linting

* Address comments.

* Fix typos and add comment.

* Add assertion and fix test.

src/common/task.h

@@ -190,6 +190,9 @@ void free_task_builder(TaskBuilder *builder);
  * @param parent_task_id The task ID of the task that submitted this task.
  * @param parent_counter A counter indicating how many tasks were submitted by
  *        the parent task prior to this one.
+ * @param actor_creation_id The actor creation ID of this task.
+ * @param actor_creation_dummy_object_id The dummy object for the corresponding
+ *        actor creation task, assuming this is an actor method.
  * @param actor_id The ID of the actor that this task is for. If it is not an
  *        actor task, then this if NIL_ACTOR_ID.
  * @param actor_handle_id The ID of the actor handle that this task was
@@ -210,8 +213,10 @@ void TaskSpec_start_construct(TaskBuilder *B,
                               UniqueID driver_id,
                               TaskID parent_task_id,
                               int64_t parent_counter,
-                              UniqueID actor_id,
-                              UniqueID actor_handle_id,
+                              ActorID actor_creation_id,
+                              ObjectID actor_creation_dummy_object_id,
+                              ActorID actor_id,
+                              ActorHandleID actor_handle_id,
                               int64_t actor_counter,
                               bool is_actor_checkpoint_method,
                               FunctionID function_id,
@@ -241,7 +246,7 @@ FunctionID TaskSpec_function(TaskSpec *spec);
  * @param spec The task_spec in question.
  * @return The actor ID of the actor the task is part of.
  */
-UniqueID TaskSpec_actor_id(TaskSpec *spec);
+ActorID TaskSpec_actor_id(TaskSpec *spec);
 
 /**
  * Return the actor handle ID of the task.
@@ -249,7 +254,7 @@ UniqueID TaskSpec_actor_id(TaskSpec *spec);
  * @param spec The task_spec in question.
  * @return The ID of the actor handle that the task was submitted through.
  */
-UniqueID TaskSpec_actor_handle_id(TaskSpec *spec);
+ActorID TaskSpec_actor_handle_id(TaskSpec *spec);
 
 /**
  * Return whether this task is for an actor.
@@ -259,6 +264,26 @@ UniqueID TaskSpec_actor_handle_id(TaskSpec *spec);
  */
 bool TaskSpec_is_actor_task(TaskSpec *spec);
 
+/// Return whether this task is an actor creation task or not.
+///
+/// \param spec The task_spec in question.
+/// \return True if this task is an actor creation task and false otherwise.
+bool TaskSpec_is_actor_creation_task(TaskSpec *spec);
+
+/// Return the actor creation ID of the task. The task must be an actor creation
+/// task.
+///
+/// \param spec The task_spec in question.
+/// \return The actor creation ID if this is an actor creation task.
+ActorID TaskSpec_actor_creation_id(TaskSpec *spec);
+
+/// Return the actor creation dummy object ID of the task. The task must be an
+/// actor task.
+///
+/// \param spec The task_spec in question.
+/// \return The actor creation dummy object ID corresponding to this actor task.
+ObjectID TaskSpec_actor_creation_dummy_object_id(TaskSpec *spec);
+
 /**
  * Return the actor counter of the task. This starts at 0 and increments by 1
  * every time a new task is submitted to run on the actor.
@@ -508,7 +533,10 @@ typedef enum {
   /** The task was not able to finish. */
   TASK_STATUS_LOST = 32,
   /** The task will be submitted for reexecution. */
-  TASK_STATUS_RECONSTRUCTING = 64
+  TASK_STATUS_RECONSTRUCTING = 64,
+  /** An actor task is cached at a local scheduler and is waiting for the
+   *  corresponding actor to be created. */
+  TASK_STATUS_ACTOR_CACHED = 128
 } scheduling_state;
 
 /** A task is an execution of a task specification.  It has a state of execution