--- a/hotspot/src/share/vm/gc/g1/dirtyCardQueue.cpp	Fri Jan 08 12:56:16 2016 +0000
+++ b/hotspot/src/share/vm/gc/g1/dirtyCardQueue.cpp	Fri Jan 08 15:41:44 2016 -0500
@@ -32,6 +32,72 @@
 #include "runtime/safepoint.hpp"
 #include "runtime/thread.inline.hpp"
 
+// Represents a set of free small integer ids.
+class FreeIdSet : public CHeapObj<mtGC> {
+  enum {
+    end_of_list = UINT_MAX,
+    claimed = UINT_MAX - 1
+  };
+
+  uint _size;
+  Monitor* _mon;
+
+  uint* _ids;
+  uint _hd;
+  uint _waiters;
+  uint _claimed;
+
+public:
+  FreeIdSet(uint size, Monitor* mon);
+  ~FreeIdSet();
+
+  // Returns an unclaimed parallel id (waiting for one to be released if
+  // necessary).
+  uint claim_par_id();
+
+  void release_par_id(uint id);
+};
+
+FreeIdSet::FreeIdSet(uint size, Monitor* mon) :
+  _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0)
+{
+  guarantee(size != 0, "must be");
+  _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC);
+  for (uint i = 0; i < size - 1; i++) {
+    _ids[i] = i+1;
+  }
+  _ids[size-1] = end_of_list; // end of list.
+}
+
+FreeIdSet::~FreeIdSet() {
+  FREE_C_HEAP_ARRAY(uint, _ids);
+}
+
+uint FreeIdSet::claim_par_id() {
+  MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
+  while (_hd == end_of_list) {
+    _waiters++;
+    _mon->wait(Mutex::_no_safepoint_check_flag);
+    _waiters--;
+  }
+  uint res = _hd;
+  _hd = _ids[res];
+  _ids[res] = claimed;  // For debugging.
+  _claimed++;
+  return res;
+}
+
+void FreeIdSet::release_par_id(uint id) {
+  MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
+  assert(_ids[id] == claimed, "Precondition.");
+  _ids[id] = _hd;
+  _hd = id;
+  _claimed--;
+  if (_waiters > 0) {
+    _mon->notify_all();
+  }
+}
+
 DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) :
   // Dirty card queues are always active, so we create them with their
   // active field set to true.
@@ -103,7 +169,8 @@
                                    int process_completed_threshold,
                                    int max_completed_queue,
                                    Mutex* lock,
-                                   DirtyCardQueueSet* fl_owner) {
+                                   DirtyCardQueueSet* fl_owner,
+                                   bool init_free_ids) {
   _mut_process_closure = cl;
   PtrQueueSet::initialize(cbl_mon,
                           fl_lock,
@@ -112,7 +179,9 @@
                           fl_owner);
   set_buffer_size(G1UpdateBufferSize);
   _shared_dirty_card_queue.set_lock(lock);
-  _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon);
+  if (init_free_ids) {
+    _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon);
+  }
 }
 
 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
@@ -120,7 +189,7 @@
 }
 
 bool DirtyCardQueueSet::mut_process_buffer(void** buf) {
-
+  guarantee(_free_ids != NULL, "must be");
   // Used to determine if we had already claimed a par_id
   // before entering this method.
   bool already_claimed = false;

--- a/hotspot/src/share/vm/gc/g1/dirtyCardQueue.hpp	Fri Jan 08 12:56:16 2016 +0000
+++ b/hotspot/src/share/vm/gc/g1/dirtyCardQueue.hpp	Fri Jan 08 15:41:44 2016 -0500
@@ -116,7 +116,8 @@
                   int process_completed_threshold,
                   int max_completed_queue,
                   Mutex* lock,
-                  DirtyCardQueueSet* fl_owner = NULL);
+                  DirtyCardQueueSet* fl_owner,
+                  bool init_free_ids = false);
 
   // The number of parallel ids that can be claimed to allow collector or
   // mutator threads to do card-processing work.

--- a/hotspot/src/share/vm/gc/g1/g1CollectedHeap.cpp	Fri Jan 08 12:56:16 2016 +0000
+++ b/hotspot/src/share/vm/gc/g1/g1CollectedHeap.cpp	Fri Jan 08 15:41:44 2016 -0500
@@ -1984,7 +1984,9 @@
                                                 DirtyCardQ_FL_lock,
                                                 concurrent_g1_refine()->yellow_zone(),
                                                 concurrent_g1_refine()->red_zone(),
-                                                Shared_DirtyCardQ_lock);
+                                                Shared_DirtyCardQ_lock,
+                                                NULL,  // fl_owner
+                                                true); // init_free_ids
 
   dirty_card_queue_set().initialize(NULL, // Should never be called by the Java code
                                     DirtyCardQ_CBL_mon,

--- a/hotspot/src/share/vm/gc/shared/workgroup.cpp	Fri Jan 08 12:56:16 2016 +0000
+++ b/hotspot/src/share/vm/gc/shared/workgroup.cpp	Fri Jan 08 15:41:44 2016 -0500
@@ -499,43 +499,3 @@
   }
   return false;
 }
-
-FreeIdSet::FreeIdSet(uint size, Monitor* mon) :
-  _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0)
-{
-  guarantee(size != 0, "must be");
-  _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC);
-  for (uint i = 0; i < size - 1; i++) {
-    _ids[i] = i+1;
-  }
-  _ids[size-1] = end_of_list; // end of list.
-}
-
-FreeIdSet::~FreeIdSet() {
-  FREE_C_HEAP_ARRAY(uint, _ids);
-}
-
-uint FreeIdSet::claim_par_id() {
-  MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
-  while (_hd == end_of_list) {
-    _waiters++;
-    _mon->wait(Mutex::_no_safepoint_check_flag);
-    _waiters--;
-  }
-  uint res = _hd;
-  _hd = _ids[res];
-  _ids[res] = claimed;  // For debugging.
-  _claimed++;
-  return res;
-}
-
-void FreeIdSet::release_par_id(uint id) {
-  MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
-  assert(_ids[id] == claimed, "Precondition.");
-  _ids[id] = _hd;
-  _hd = id;
-  _claimed--;
-  if (_waiters > 0) {
-    _mon->notify_all();
-  }
-}

--- a/hotspot/src/share/vm/gc/shared/workgroup.hpp	Fri Jan 08 12:56:16 2016 +0000
+++ b/hotspot/src/share/vm/gc/shared/workgroup.hpp	Fri Jan 08 15:41:44 2016 -0500
@@ -378,30 +378,4 @@
   bool all_tasks_completed();
 };
 
-// Represents a set of free small integer ids.
-class FreeIdSet : public CHeapObj<mtGC> {
-  enum {
-    end_of_list = UINT_MAX,
-    claimed = UINT_MAX - 1
-  };
-
-  uint _size;
-  Monitor* _mon;
-
-  uint* _ids;
-  uint _hd;
-  uint _waiters;
-  uint _claimed;
-
-public:
-  FreeIdSet(uint size, Monitor* mon);
-  ~FreeIdSet();
-
-  // Returns an unclaimed parallel id (waiting for one to be released if
-  // necessary).
-  uint claim_par_id();
-
-  void release_par_id(uint id);
-};
-
 #endif // SHARE_VM_GC_SHARED_WORKGROUP_HPP