--- a/hotspot/src/share/vm/gc/g1/ptrQueue.cpp	Thu Feb 18 16:15:28 2016 +0100
+++ b/hotspot/src/share/vm/gc/g1/ptrQueue.cpp	Wed Feb 24 13:18:54 2016 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,6 +30,8 @@
 #include "runtime/mutexLocker.hpp"
 #include "runtime/thread.inline.hpp"
 
+#include <new>
+
 PtrQueue::PtrQueue(PtrQueueSet* qset, bool permanent, bool active) :
   _qset(qset), _buf(NULL), _index(0), _sz(0), _active(active),
   _permanent(permanent), _lock(NULL)
@@ -87,6 +89,19 @@
 }
 
 
+BufferNode* BufferNode::allocate(size_t byte_size) {
+  assert(byte_size > 0, "precondition");
+  assert(is_size_aligned(byte_size, sizeof(void**)),
+         "Invalid buffer size " SIZE_FORMAT, byte_size);
+  void* data = NEW_C_HEAP_ARRAY(char, buffer_offset() + byte_size, mtGC);
+  return new (data) BufferNode;
+}
+
+void BufferNode::deallocate(BufferNode* node) {
+  node->~BufferNode();
+  FREE_C_HEAP_ARRAY(char, node);
+}
+
 PtrQueueSet::PtrQueueSet(bool notify_when_complete) :
   _max_completed_queue(0),
   _cbl_mon(NULL), _fl_lock(NULL),
@@ -123,17 +138,23 @@
 
 void** PtrQueueSet::allocate_buffer() {
   assert(_sz > 0, "Didn't set a buffer size.");
-  MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
-  if (_fl_owner->_buf_free_list != NULL) {
-    void** res = BufferNode::make_buffer_from_node(_fl_owner->_buf_free_list);
-    _fl_owner->_buf_free_list = _fl_owner->_buf_free_list->next();
-    _fl_owner->_buf_free_list_sz--;
-    return res;
+  BufferNode* node = NULL;
+  {
+    MutexLockerEx x(_fl_owner->_fl_lock, Mutex::_no_safepoint_check_flag);
+    node = _fl_owner->_buf_free_list;
+    if (node != NULL) {
+      _fl_owner->_buf_free_list = node->next();
+      _fl_owner->_buf_free_list_sz--;
+    }
+  }
+  if (node == NULL) {
+    node = BufferNode::allocate(_sz);
   } else {
-    // Allocate space for the BufferNode in front of the buffer.
-    char *b =  NEW_C_HEAP_ARRAY(char, _sz + BufferNode::aligned_size(), mtGC);
-    return BufferNode::make_buffer_from_block(b);
+    // Reinitialize buffer obtained from free list.
+    node->set_index(0);
+    node->set_next(NULL);
   }
+  return BufferNode::make_buffer_from_node(node);
 }
 
 void PtrQueueSet::deallocate_buffer(void** buf) {
@@ -150,13 +171,13 @@
   // For now we'll adopt the strategy of deleting half.
   MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag);
   size_t n = _buf_free_list_sz / 2;
-  while (n > 0) {
-    assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong.");
-    void* b = BufferNode::make_block_from_node(_buf_free_list);
-    _buf_free_list = _buf_free_list->next();
-    FREE_C_HEAP_ARRAY(char, b);
-    _buf_free_list_sz --;
-    n--;
+  for (size_t i = 0; i < n; ++i) {
+    assert(_buf_free_list != NULL,
+           "_buf_free_list_sz is wrong: " SIZE_FORMAT, _buf_free_list_sz);
+    BufferNode* node = _buf_free_list;
+    _buf_free_list = node->next();
+    _buf_free_list_sz--;
+    BufferNode::deallocate(node);
   }
 }
 
@@ -236,8 +257,9 @@
 
 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index) {
   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
-  BufferNode* cbn = BufferNode::new_from_buffer(buf);
+  BufferNode* cbn = BufferNode::make_node_from_buffer(buf);
   cbn->set_index(index);
+  cbn->set_next(NULL);
   if (_completed_buffers_tail == NULL) {
     assert(_completed_buffers_head == NULL, "Well-formedness");
     _completed_buffers_head = cbn;