--- old/src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.hpp	2019-06-18 13:08:45.414209569 -0400
+++ new/src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.hpp	2019-06-18 13:08:45.081209191 -0400
@@ -61,6 +61,98 @@
   void oops_do(OopClosure* cl, uint worker_id);
 };
 
+class ShenandoahWeakSerialRoot {
+  typedef void (*WeakOopsDo)(BoolObjectClosure*, OopClosure*);
+private:
+  volatile bool                             _claimed;
+  const WeakOopsDo                          _weak_oops_do;
+  const ShenandoahPhaseTimings::GCParPhases _phase;
+
+public:
+  ShenandoahWeakSerialRoot(WeakOopsDo oops_do, ShenandoahPhaseTimings::GCParPhases);
+  void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* keep_alive, uint worker_id);
+};
+
+#if INCLUDE_JVMTI
+class ShenandoahJVMTIWeakRoot : public ShenandoahWeakSerialRoot {
+public:
+  ShenandoahJVMTIWeakRoot();
+};
+#endif // INCLUDE_JVMTI
+
+#if INCLUDE_JFR
+class ShenandoahJFRWeakRoot : public ShenandoahWeakSerialRoot {
+public:
+  ShenandoahJFRWeakRoot();
+};
+#endif // INCLUDE_JFR
+
+class ShenandoahSerialWeakRoots {
+private:
+  JVMTI_ONLY(ShenandoahJVMTIWeakRoot _jvmti_weak_roots;)
+  JFR_ONLY(ShenandoahJFRWeakRoot     _jfr_weak_roots;)
+public:
+  void weak_oops_do(BoolObjectClosure* is_alive, OopClosure* keep_alive, uint worker_id);
+  void weak_oops_do(OopClosure* cl, uint worker_id);
+};
+
+template <bool CONCURRENT = false>
+class ShenandoahWeakRoot {
+private:
+  OopStorage::ParState<CONCURRENT, false /* is_const */> _itr;
+  const ShenandoahPhaseTimings::GCParPhases _phase;
+public:
+  ShenandoahWeakRoot(OopStorage* storage, ShenandoahPhaseTimings::GCParPhases phase);
+
+  template <typename Closure>
+  void oops_do(Closure* cl, uint worker_id);
+};
+
+template <>
+class ShenandoahWeakRoot<false> {
+private:
+  OopStorage::ParState<false /* concurrent */, false /* is_const */> _itr;
+  const ShenandoahPhaseTimings::GCParPhases _phase;
+
+public:
+  ShenandoahWeakRoot(OopStorage* storage, ShenandoahPhaseTimings::GCParPhases phase);
+
+  template <typename IsAliveClosure, typename KeepAliveClosure>
+  void weak_oops_do(IsAliveClosure* is_alive, KeepAliveClosure* keep_alive, uint worker_id);
+};
+
+template <bool CONCURRENT = false>
+class ShenandoahWeakRoots {
+private:
+  ShenandoahWeakRoot<CONCURRENT>  _jni_roots;
+  ShenandoahWeakRoot<CONCURRENT>  _string_table_roots;
+  ShenandoahWeakRoot<CONCURRENT>  _resolved_method_table_roots;
+  ShenandoahWeakRoot<CONCURRENT>  _vm_roots;
+
+public:
+  ShenandoahWeakRoots();
+
+  template <typename Closure>
+  void oops_do(Closure* cl, uint worker_id = 0);
+};
+
+template <>
+class ShenandoahWeakRoots<false /* concurrent */> {
+private:
+  ShenandoahWeakRoot<>  _jni_roots;
+  ShenandoahWeakRoot<>  _string_table_roots;
+  ShenandoahWeakRoot<>  _resolved_method_table_roots;
+  ShenandoahWeakRoot<>  _vm_roots;
+public:
+  ShenandoahWeakRoots();
+
+  template <typename Closure>
+  void oops_do(Closure* cl, uint worker_id = 0);
+
+  template <typename IsAliveClosure, typename KeepAliveClosure>
+  void weak_oops_do(IsAliveClosure* is_alive, KeepAliveClosure* keep_alive, uint worker_id);
+};
+
 template <bool CONCURRENT = false>
 class ShenandoahJNIHandleRoots {
 private:
@@ -84,18 +176,6 @@
   void threads_do(ThreadClosure* tc, uint worker_id);
 };
 
-class ShenandoahWeakRoots {
-private:
-  WeakProcessorPhaseTimes _process_timings;
-  WeakProcessor::Task     _task;
-public:
-  ShenandoahWeakRoots(uint n_workers);
-  ~ShenandoahWeakRoots();
-
-  template <typename IsAlive, typename KeepAlive>
-  void oops_do(IsAlive* is_alive, KeepAlive* keep_alive, uint worker_id);
-};
-
 class ShenandoahStringDedupRoots {
 public:
   ShenandoahStringDedupRoots();
@@ -168,7 +248,8 @@
   ShenandoahJNIHandleRoots<>       _jni_roots;
   ShenandoahClassLoaderDataRoots   _cld_roots;
   ShenandoahThreadRoots            _thread_roots;
-  ShenandoahWeakRoots              _weak_roots;
+  ShenandoahSerialWeakRoots        _serial_weak_roots;
+  ShenandoahWeakRoots<>            _weak_roots;
   ShenandoahStringDedupRoots       _dedup_roots;
   ShenandoahCodeCacheRoots<ShenandoahCsetCodeRootsIterator> _code_roots;
   bool                             _include_concurrent_roots;
@@ -186,7 +267,8 @@
   ShenandoahJNIHandleRoots<>       _jni_roots;
   ShenandoahClassLoaderDataRoots   _cld_roots;
   ShenandoahThreadRoots            _thread_roots;
-  ShenandoahWeakRoots              _weak_roots;
+  ShenandoahSerialWeakRoots        _serial_weak_roots;
+  ShenandoahWeakRoots<>            _weak_roots;
   ShenandoahStringDedupRoots       _dedup_roots;
   ShenandoahCodeCacheRoots<ShenandoahCsetCodeRootsIterator> _code_roots;
   const bool                       _update_code_cache;
@@ -205,7 +287,8 @@
   ShenandoahJNIHandleRoots<>       _jni_roots;
   ShenandoahClassLoaderDataRoots   _cld_roots;
   ShenandoahThreadRoots            _thread_roots;
-  ShenandoahWeakRoots              _weak_roots;
+  ShenandoahSerialWeakRoots        _serial_weak_roots;
+  ShenandoahWeakRoots<>            _weak_roots;
   ShenandoahStringDedupRoots       _dedup_roots;
   ShenandoahCodeCacheRoots<ShenandoahAllCodeRootsIterator> _code_roots;