diff -r 98408c7c0b73 -r 495c05ee2a9a src/hotspot/share/gc/shared/workerDataArray.hpp
--- a/src/hotspot/share/gc/shared/workerDataArray.hpp	Fri Dec 07 13:15:35 2018 +0100
+++ b/src/hotspot/share/gc/shared/workerDataArray.hpp	Fri Dec 07 13:54:45 2018 +0100
@@ -34,7 +34,7 @@
 class WorkerDataArray  : public CHeapObj<mtGC> {
   friend class WDAPrinter;
 public:
-  static const uint MaxThreadWorkItems = 3;
+  static const uint MaxThreadWorkItems = 4;
 private:
   T*          _data;
   uint        _length;
@@ -49,6 +49,8 @@
   void link_thread_work_items(WorkerDataArray<size_t>* thread_work_items, uint index = 0);
   void set_thread_work_item(uint worker_i, size_t value, uint index = 0);
   void add_thread_work_item(uint worker_i, size_t value, uint index = 0);
+  void set_or_add_thread_work_item(uint worker_i, size_t value, uint index = 0);
+
   WorkerDataArray<size_t>* thread_work_items(uint index = 0) const {
     assert(index < MaxThreadWorkItems, "Tried to access thread work item %u max %u", index, MaxThreadWorkItems);
     return _thread_work_items[index];