diff -r 000000000000 -r f90c822e73f8 src/share/vm/services/memTrackWorker.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/services/memTrackWorker.hpp	Wed Apr 27 01:25:04 2016 +0800
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2013, 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_SERVICES_MEM_TRACK_WORKER_HPP
+#define SHARE_VM_SERVICES_MEM_TRACK_WORKER_HPP
+
+#include "memory/allocation.hpp"
+#include "runtime/thread.hpp"
+#include "services/memRecorder.hpp"
+
+// Maximum MAX_GENERATIONS generation data can be tracked.
+#define MAX_GENERATIONS  512
+
+class GenerationData VALUE_OBJ_CLASS_SPEC {
+ private:
+  int           _number_of_classes;
+  MemRecorder*  _recorder_list;
+
+ public:
+  GenerationData(): _number_of_classes(0), _recorder_list(NULL) { }
+
+  inline int  number_of_classes() const { return _number_of_classes; }
+  inline void set_number_of_classes(long num) { _number_of_classes = num; }
+
+  inline MemRecorder* next_recorder() {
+    if (_recorder_list == NULL) {
+      return NULL;
+    } else {
+      MemRecorder* tmp = _recorder_list;
+      _recorder_list = _recorder_list->next();
+      return tmp;
+    }
+  }
+
+  inline bool has_more_recorder() const {
+    return (_recorder_list != NULL);
+  }
+
+  // add recorders to this generation
+  void add_recorders(MemRecorder* head) {
+    if (head != NULL) {
+      if (_recorder_list == NULL) {
+        _recorder_list = head;
+      } else {
+        MemRecorder* tmp = _recorder_list;
+        for (; tmp->next() != NULL; tmp = tmp->next());
+        tmp->set_next(head);
+      }
+    }
+  }
+
+  void reset();
+
+  NOT_PRODUCT(MemRecorder* peek() const { return _recorder_list; })
+};
+
+class MemTrackWorker : public NamedThread {
+ private:
+  // circular buffer. This buffer contains generation data to be merged into global
+  // snaphsot.
+  // Each slot holds a generation
+  GenerationData  _gen[MAX_GENERATIONS];
+  int             _head, _tail; // head and tail pointers to above circular buffer
+
+  bool            _has_error;
+
+  MemSnapshot*    _snapshot;
+
+ public:
+  MemTrackWorker(MemSnapshot* snapshot);
+  ~MemTrackWorker();
+  _NOINLINE_ void* operator new(size_t size) throw();
+  _NOINLINE_ void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw();
+
+  void start();
+  void run();
+
+  inline bool has_error() const { return _has_error; }
+
+  // task at synchronization point
+  void at_sync_point(MemRecorder* pending_recorders, int number_of_classes);
+
+  // for debugging purpose, they are not thread safe.
+  NOT_PRODUCT(static int count_recorder(const MemRecorder* head);)
+  NOT_PRODUCT(int count_pending_recorders() const;)
+
+  NOT_PRODUCT(int _sync_point_count;)
+  NOT_PRODUCT(int _merge_count;)
+  NOT_PRODUCT(int _last_gen_in_use;)
+
+  // how many generations are queued
+  inline int generations_in_use() const {
+    return (_tail >= _head ? (_tail - _head + 1) : (MAX_GENERATIONS - (_head - _tail) + 1));
+  }
+};
+
+#endif // SHARE_VM_SERVICES_MEM_TRACK_WORKER_HPP