--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/g1RegionToSpaceMapper.hpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2014, 2015, 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_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP
+#define SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP
+
+#include "gc/g1/g1PageBasedVirtualSpace.hpp"
+#include "memory/allocation.hpp"
+#include "utilities/debug.hpp"
+
+class WorkGang;
+
+class G1MappingChangedListener VALUE_OBJ_CLASS_SPEC {
+ public:
+  // Fired after commit of the memory, i.e. the memory this listener is registered
+  // for can be accessed.
+  // Zero_filled indicates that the memory can be considered as filled with zero bytes
+  // when called.
+  virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled) = 0;
+};
+
+// Maps region based commit/uncommit requests to the underlying page sized virtual
+// space.
+class G1RegionToSpaceMapper : public CHeapObj<mtGC> {
+ private:
+  G1MappingChangedListener* _listener;
+ protected:
+  // Backing storage.
+  G1PageBasedVirtualSpace _storage;
+
+  size_t _region_granularity;
+  // Mapping management
+  CHeapBitMap _commit_map;
+
+  G1RegionToSpaceMapper(ReservedSpace rs, size_t used_size, size_t page_size, size_t region_granularity, size_t commit_factor, MemoryType type);
+
+  void fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled);
+ public:
+  MemRegion reserved() { return _storage.reserved(); }
+
+  size_t reserved_size() { return _storage.reserved_size(); }
+  size_t committed_size() { return _storage.committed_size(); }
+
+  void set_mapping_changed_listener(G1MappingChangedListener* listener) { _listener = listener; }
+
+  virtual ~G1RegionToSpaceMapper() {}
+
+  bool is_committed(uintptr_t idx) const {
+    return _commit_map.at(idx);
+  }
+
+  virtual void commit_regions(uint start_idx, size_t num_regions = 1, WorkGang* pretouch_workers = NULL) = 0;
+  virtual void uncommit_regions(uint start_idx, size_t num_regions = 1) = 0;
+
+  // Creates an appropriate G1RegionToSpaceMapper for the given parameters.
+  // The actual space to be used within the given reservation is given by actual_size.
+  // This is because some OSes need to round up the reservation size to guarantee
+  // alignment of page_size.
+  // The byte_translation_factor defines how many bytes in a region correspond to
+  // a single byte in the data structure this mapper is for.
+  // Eg. in the card table, this value corresponds to the size a single card
+  // table entry corresponds to in the heap.
+  static G1RegionToSpaceMapper* create_mapper(ReservedSpace rs,
+                                              size_t actual_size,
+                                              size_t page_size,
+                                              size_t region_granularity,
+                                              size_t byte_translation_factor,
+                                              MemoryType type);
+};
+
+#endif // SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP