--- old/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	2019-08-29 14:09:39.721309086 -0400
+++ new/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	2019-08-29 14:09:39.449294497 -0400
@@ -1687,8 +1687,7 @@
   // process_completed_buffers_threshold and max_completed_buffers are updated
   // later, based on the concurrent refinement object.
   G1BarrierSet::dirty_card_queue_set().initialize(DirtyCardQ_CBL_mon,
-                                                  &bs->dirty_card_queue_buffer_allocator(),
-                                                  true); // init_free_ids
+                                                  &bs->dirty_card_queue_buffer_allocator());
 
   // Create the hot card cache.
   _hot_card_cache = new G1HotCardCache(this);
--- old/src/hotspot/share/gc/g1/g1DirtyCardQueue.cpp	2019-08-29 14:09:41.249391043 -0400
+++ new/src/hotspot/share/gc/g1/g1DirtyCardQueue.cpp	2019-08-29 14:09:40.961375596 -0400
@@ -91,7 +91,7 @@
   _notify_when_complete(notify_when_complete),
   _max_completed_buffers(MaxCompletedBuffersUnlimited),
   _completed_buffers_padding(0),
-  _free_ids(NULL),
+  _free_ids(0, num_par_ids()),
   _processed_buffers_mut(0),
   _processed_buffers_rs_thread(0)
 {
@@ -100,7 +100,6 @@
 
 G1DirtyCardQueueSet::~G1DirtyCardQueueSet() {
   abandon_completed_buffers();
-  delete _free_ids;
 }
 
 // Determines how many mutator threads can process the buffers in parallel.
@@ -109,14 +108,10 @@
 }
 
 void G1DirtyCardQueueSet::initialize(Monitor* cbl_mon,
-                                     BufferNode::Allocator* allocator,
-                                     bool init_free_ids) {
+                                     BufferNode::Allocator* allocator) {
   PtrQueueSet::initialize(allocator);
   assert(_cbl_mon == NULL, "Init order issue?");
   _cbl_mon = cbl_mon;
-  if (init_free_ids) {
-    _free_ids = new G1FreeIdSet(0, num_par_ids());
-  }
 }
 
 void G1DirtyCardQueueSet::handle_zero_index_for_thread(Thread* t) {
@@ -291,12 +286,10 @@
 }
 
 bool G1DirtyCardQueueSet::mut_process_buffer(BufferNode* node) {
-  guarantee(_free_ids != NULL, "must be");
-
-  uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id
+  uint worker_id = _free_ids.claim_par_id(); // temporarily claim an id
   G1RefineCardConcurrentlyClosure cl;
-  bool result = apply_closure_to_buffer(&cl, node, worker_i);
-  _free_ids->release_par_id(worker_i); // release the id
+  bool result = apply_closure_to_buffer(&cl, node, worker_id);
+  _free_ids.release_par_id(worker_id); // release the id
 
   if (result) {
     assert_fully_consumed(node, buffer_size());
--- old/src/hotspot/share/gc/g1/g1DirtyCardQueue.hpp	2019-08-29 14:09:42.761472142 -0400
+++ new/src/hotspot/share/gc/g1/g1DirtyCardQueue.hpp	2019-08-29 14:09:42.469456480 -0400
@@ -25,12 +25,12 @@
 #ifndef SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP
 #define SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP
 
+#include "gc/g1/g1FreeIdSet.hpp"
 #include "gc/shared/ptrQueue.hpp"
 #include "memory/allocation.hpp"
 
 class G1CardTableEntryClosure;
 class G1DirtyCardQueueSet;
-class G1FreeIdSet;
 class G1RedirtyCardsQueueSet;
 class Thread;
 class Monitor;
@@ -118,7 +118,7 @@
   size_t _completed_buffers_padding;
   static const size_t MaxCompletedBuffersUnlimited = SIZE_MAX;
 
-  G1FreeIdSet* _free_ids;
+  G1FreeIdSet _free_ids;
 
   // The number of completed buffers processed by mutator and rs thread,
   // respectively.
@@ -129,9 +129,7 @@
   G1DirtyCardQueueSet(bool notify_when_complete = true);
   ~G1DirtyCardQueueSet();
 
-  void initialize(Monitor* cbl_mon,
-                  BufferNode::Allocator* allocator,
-                  bool init_free_ids = false);
+  void initialize(Monitor* cbl_mon, BufferNode::Allocator* allocator);
 
   // The number of parallel ids that can be claimed to allow collector or
   // mutator threads to do card-processing work.
--- old/src/hotspot/share/gc/g1/g1FreeIdSet.hpp	2019-08-29 14:09:44.257552383 -0400
+++ new/src/hotspot/share/gc/g1/g1FreeIdSet.hpp	2019-08-29 14:09:43.965536721 -0400
@@ -25,7 +25,6 @@
 #ifndef SHARE_GC_G1_G1FREEIDSET_HPP
 #define SHARE_GC_G1_G1FREEIDSET_HPP
 
-#include "memory/allocation.hpp"
 #include "runtime/semaphore.hpp"
 #include "utilities/globalDefinitions.hpp"
 
@@ -34,7 +33,7 @@
 // contiguous range from 'start' to 'start + size'.  Used to obtain a
 // distinct worker_id value for a mutator thread that doesn't normally
 // have such an id.
-class G1FreeIdSet : public CHeapObj<mtGC> {
+class G1FreeIdSet {
   Semaphore _sem;
   uint* _next;
   uint _start;