--- /dev/null	2015-10-06 23:29:51.451421828 +0200
+++ new/src/share/vm/gc/shenandoah/shenandoahConcurrentThread.hpp	2015-10-14 13:54:49.439037819 +0200
@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
+ *
+ * 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_SHENANDOAH_SHENANDOAHCONCURRENTTHREAD_HPP
+#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTTHREAD_HPP
+
+#include "gc/shared/concurrentGCThread.hpp"
+#include "gc/g1/suspendibleThreadSet.hpp"
+#include "gc/shared/gcCause.hpp"
+#include "memory/resourceArea.hpp"
+
+// For now we just want to have a concurrent marking thread.
+// Once we have that working we will build a concurrent evacuation thread.
+
+class ShenandoahConcurrentThread: public ConcurrentGCThread {
+  friend class VMStructs;
+
+ public:
+  virtual void run();
+
+ private:
+  volatile bool                    _concurrent_mark_started;
+  volatile bool                    _concurrent_mark_in_progress;
+  volatile bool                    _concurrent_mark_aborted;
+
+  int _epoch;
+
+  static SurrogateLockerThread* _slt;
+  static SuspendibleThreadSet _sts;
+
+  bool _do_full_gc;
+  GCCause::Cause _full_gc_cause;
+
+  void sleepBeforeNextCycle();
+
+ public:
+  // Constructor
+  ShenandoahConcurrentThread();
+  ~ShenandoahConcurrentThread();
+
+  static void makeSurrogateLockerThread(TRAPS);
+  static SurrogateLockerThread* slt() { return _slt; }
+
+  // Printing
+  void print_on(outputStream* st) const;
+  void print() const;
+
+  void set_cm_started();
+  void clear_cm_started();
+  bool cm_started();
+
+  void set_cm_in_progress();
+  void clear_cm_in_progress();
+  bool cm_in_progress();
+
+  void cm_abort() { _concurrent_mark_aborted = true;}
+  bool cm_has_aborted() { return _concurrent_mark_aborted;}
+  void clear_cm_aborted() { _concurrent_mark_aborted = false;}
+
+  void do_full_gc(GCCause::Cause cause);
+
+  void schedule_full_gc();
+
+  // 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 cm_started() || cm_in_progress(); }
+
+  char* name() const { return (char*)"ShenandoahConcurrentThread";}
+  void start();
+  void yield();
+
+  static void safepoint_synchronize();
+  static void safepoint_desynchronize();
+
+  void shutdown();
+};
+
+#endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTTHREAD_HPP