8280958: G1/Parallel: Unify marking code structure

Reviewed-by: ayang, kbarrett

Author: Thomas Schatzl

src/hotspot/share/gc/g1/g1FullGCMarker.cpp

@@ -55,7 +55,7 @@ void G1FullGCMarker::complete_marking(OopQueueSet* oop_stacks,
                                       ObjArrayTaskQueueSet* array_stacks,
                                       TaskTerminator* terminator) {
   do {
-    drain_stack();
+    follow_marking_stacks();
     ObjArrayTask steal_array;
     if (array_stacks->steal(_worker_id, steal_array)) {
       follow_array_chunk(objArrayOop(steal_array.obj()), steal_array.index());

src/hotspot/share/gc/g1/g1FullGCMarker.hpp

@@ -79,12 +79,12 @@ class G1FullGCMarker : public CHeapObj<mtGC> {
   inline void follow_array(objArrayOop array);
   inline void follow_array_chunk(objArrayOop array, int index);
 
-  inline void drain_oop_stack();
-  // Transfer contents from the objArray task queue overflow stack to the shared
-  // objArray stack.
+  inline void publish_and_drain_oop_tasks();
+  // Try to publish all contents from the objArray task queue overflow stack to
+  // the shared objArray stack.
   // Returns true and a valid task if there has not been enough space in the shared
-  // objArray stack, otherwise the task is invalid.
-  inline bool transfer_objArray_overflow_stack(ObjArrayTask& task);
+  // objArray stack, otherwise returns false and the task is invalid.
+  inline bool publish_or_pop_objarray_tasks(ObjArrayTask& task);
 
 public:
   G1FullGCMarker(G1FullCollector* collector,
@@ -103,7 +103,7 @@ class G1FullGCMarker : public CHeapObj<mtGC> {
   inline void follow_klass(Klass* k);
   inline void follow_cld(ClassLoaderData* cld);
 
-  inline void drain_stack();
+  inline void follow_marking_stacks();
   void complete_marking(OopQueueSet* oop_stacks,
                         ObjArrayTaskQueueSet* array_stacks,
                         TaskTerminator* terminator);

src/hotspot/share/gc/g1/g1FullGCMarker.inline.hpp

@@ -151,7 +151,7 @@ inline void G1FullGCMarker::follow_object(oop obj) {
   }
 }
 
-inline void G1FullGCMarker::drain_oop_stack() {
+inline void G1FullGCMarker::publish_and_drain_oop_tasks() {
   oop obj;
   while (_oop_stack.pop_overflow(obj)) {
     if (!_oop_stack.try_push_to_taskqueue(obj)) {
@@ -165,7 +165,7 @@ inline void G1FullGCMarker::drain_oop_stack() {
   }
 }
 
-inline bool G1FullGCMarker::transfer_objArray_overflow_stack(ObjArrayTask& task) {
+inline bool G1FullGCMarker::publish_or_pop_objarray_tasks(ObjArrayTask& task) {
   // It is desirable to move as much as possible work from the overflow queue to
   // the shared queue as quickly as possible.
   while (_objarray_stack.pop_overflow(task)) {
@@ -176,15 +176,15 @@ inline bool G1FullGCMarker::transfer_objArray_overflow_stack(ObjArrayTask& task)
   return false;
 }
 
-void G1FullGCMarker::drain_stack() {
+void G1FullGCMarker::follow_marking_stacks() {
   do {
     // First, drain regular oop stack.
-    drain_oop_stack();
+    publish_and_drain_oop_tasks();
 
     // Then process ObjArrays one at a time to avoid marking stack bloat.
     ObjArrayTask task;
-    if (transfer_objArray_overflow_stack(task) ||
-      _objarray_stack.pop_local(task)) {
+    if (publish_or_pop_objarray_tasks(task) ||
+        _objarray_stack.pop_local(task)) {
       follow_array_chunk(objArrayOop(task.obj()), task.index());
     }
   } while (!is_empty());

src/hotspot/share/gc/g1/g1FullGCOopClosures.cpp

@@ -36,7 +36,7 @@
 G1IsAliveClosure::G1IsAliveClosure(G1FullCollector* collector) :
   G1IsAliveClosure(collector, collector->mark_bitmap()) { }
 
-void G1FollowStackClosure::do_void() { _marker->drain_stack(); }
+void G1FollowStackClosure::do_void() { _marker->follow_marking_stacks(); }
 
 void G1FullKeepAliveClosure::do_oop(oop* p) { do_oop_work(p); }
 void G1FullKeepAliveClosure::do_oop(narrowOop* p) { do_oop_work(p); }

src/hotspot/share/gc/parallel/psCompactionManager.cpp

@@ -113,7 +113,19 @@ ParCompactionManager::gc_thread_compaction_manager(uint index) {
   return _manager_array[index];
 }
 
-bool ParCompactionManager::transfer_from_overflow_stack(ObjArrayTask& task) {
+inline void ParCompactionManager::publish_and_drain_oop_tasks() {
+  oop obj;
+  while (marking_stack()->pop_overflow(obj)) {
+    if (!marking_stack()->try_push_to_taskqueue(obj)) {
+      follow_contents(obj);
+    }
+  }
+  while (marking_stack()->pop_local(obj)) {
+    follow_contents(obj);
+  }
+}
+
+bool ParCompactionManager::publish_or_pop_objarray_tasks(ObjArrayTask& task) {
   while (_objarray_stack.pop_overflow(task)) {
     if (!_objarray_stack.try_push_to_taskqueue(task)) {
       return true;
@@ -126,19 +138,12 @@ void ParCompactionManager::follow_marking_stacks() {
   do {
     // First, try to move tasks from the overflow stack into the shared buffer, so
     // that other threads can steal. Otherwise process the overflow stack first.
-    oop obj;
-    while (marking_stack()->pop_overflow(obj)) {
-      if (!marking_stack()->try_push_to_taskqueue(obj)) {
-        follow_contents(obj);
-      }
-    }
-    while (marking_stack()->pop_local(obj)) {
-      follow_contents(obj);
-    }
+    publish_and_drain_oop_tasks();
 
     // Process ObjArrays one at a time to avoid marking stack bloat.
     ObjArrayTask task;
-    if (transfer_from_overflow_stack(task) || _objarray_stack.pop_local(task)) {
+    if (publish_or_pop_objarray_tasks(task) ||
+        _objarray_stack.pop_local(task)) {
       follow_array((objArrayOop)task.obj(), task.index());
     }
   } while (!marking_stacks_empty());

src/hotspot/share/gc/parallel/psCompactionManager.hpp

@@ -97,7 +97,12 @@ class ParCompactionManager : public CHeapObj<mtGC> {
 
   static void initialize(ParMarkBitMap* mbm);
 
-  bool transfer_from_overflow_stack(ObjArrayTask& task);
+  void publish_and_drain_oop_tasks();
+  // Try to publish all contents from the objArray task queue overflow stack to
+  // the shared objArray stack.
+  // Returns true and a valid task if there has not been enough space in the shared
+  // objArray stack, otherwise returns false and the task is invalid.
+  bool publish_or_pop_objarray_tasks(ObjArrayTask& task);
  protected:
   // Array of task queues.  Needed by the task terminator.
   static RegionTaskQueueSet* region_task_queues()      { return _region_task_queues; }