--- /dev/null	2018-05-09 06:13:36.966491568 +0200
+++ new/src/hotspot/share/memory/metaspace/blockFreelist.hpp	2018-05-09 12:24:36.071599547 +0200
@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2018, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP_
+#define SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP_
+
+#include "memory/allocation.hpp"
+#include "memory/binaryTreeDictionary.hpp"
+#include "memory/freeList.hpp"
+#include "memory/metaspace/smallBlocks.hpp"
+#include "memory/metaspace/metablock.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+namespace metaspace {
+namespace internals {
+
+typedef BinaryTreeDictionary<Metablock, FreeList<Metablock> > BlockTreeDictionary;
+
+// Used to manage the free list of Metablocks (a block corresponds
+// to the allocation of a quantum of metadata).
+class BlockFreelist : public CHeapObj<mtClass> {
+
+  BlockTreeDictionary* const _dictionary;
+  SmallBlocks* _small_blocks;
+
+  // Only allocate and split from freelist if the size of the allocation
+  // is at least 1/4th the size of the available block.
+  const static int WasteMultiplier = 4;
+
+  // Accessors
+  BlockTreeDictionary* dictionary() const { return _dictionary; }
+  SmallBlocks* small_blocks() {
+    if (_small_blocks == NULL) {
+      _small_blocks = new SmallBlocks();
+    }
+    return _small_blocks;
+  }
+
+ public:
+
+  BlockFreelist();
+  ~BlockFreelist();
+
+  // Get and return a block to the free list
+  MetaWord* get_block(size_t word_size);
+  void return_block(MetaWord* p, size_t word_size);
+
+  // Returns the total size, in words, of all blocks kept in this structure.
+  size_t total_size() const  {
+    size_t result = dictionary()->total_size();
+    if (_small_blocks != NULL) {
+      result = result + _small_blocks->total_size();
+    }
+    return result;
+  }
+
+  // Returns the number of all blocks kept in this structure.
+  uintx num_blocks() const {
+    uintx result = dictionary()->total_free_blocks();
+    if (_small_blocks != NULL) {
+      result = result + _small_blocks->total_num_blocks();
+    }
+    return result;
+  }
+
+  static size_t min_dictionary_size()   { return TreeChunk<Metablock, FreeList<Metablock> >::min_size(); }
+  void print_on(outputStream* st) const;
+};
+
+} // namespace metaspace
+} // namespace internals
+
+#endif /* SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP_ */