--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/concurrentMarkThread.hpp	Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2001, 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_CONCURRENTMARKTHREAD_HPP
+#define SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP
+
+#include "gc/shared/concurrentGCThread.hpp"
+
+// The Concurrent Mark GC Thread (could be several in the future).
+// This is copied from the Concurrent Mark Sweep GC Thread
+// Still under construction.
+
+class ConcurrentMark;
+
+class ConcurrentMarkThread: public ConcurrentGCThread {
+  friend class VMStructs;
+
+  double _vtime_start;  // Initial virtual time.
+  double _vtime_accum;  // Accumulated virtual time.
+
+  double _vtime_mark_accum;
+
+ public:
+  virtual void run();
+
+ private:
+  ConcurrentMark*                  _cm;
+  volatile bool                    _started;
+  volatile bool                    _in_progress;
+
+  void sleepBeforeNextCycle();
+
+  static SurrogateLockerThread*         _slt;
+
+ public:
+  // Constructor
+  ConcurrentMarkThread(ConcurrentMark* cm);
+
+  static void makeSurrogateLockerThread(TRAPS);
+  static SurrogateLockerThread* slt() { return _slt; }
+
+  // Total virtual time so far.
+  double vtime_accum();
+  // Marking virtual time so far
+  double vtime_mark_accum();
+
+  ConcurrentMark* cm()     { return _cm; }
+
+  void set_started()       { assert(!_in_progress, "cycle in progress"); _started = true;  }
+  void clear_started()     { assert(_in_progress, "must be starting a cycle"); _started = false; }
+  bool started()           { return _started;  }
+
+  void set_in_progress()   { assert(_started, "must be starting a cycle"); _in_progress = true;  }
+  void clear_in_progress() { assert(!_started, "must not be starting a new cycle"); _in_progress = false; }
+  bool in_progress()       { return _in_progress;  }
+
+  // This flag returns true from the moment a marking cycle is
+  // initiated (during the initial-mark pause when started() is set)
+  // to the moment when the cycle completes (just after the next
+  // marking bitmap has been cleared and in_progress() is
+  // cleared). While this flag is true we will not start another cycle
+  // so that cycles do not overlap. We cannot use just in_progress()
+  // as the CM thread might take some time to wake up before noticing
+  // that started() is set and set in_progress().
+  bool during_cycle()      { return started() || in_progress(); }
+
+  // shutdown
+  void stop();
+};
+
+#endif // SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP