concurrentMarkThread.hpp

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARKTHREAD_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARKTHREAD_HPP

#include "gc_implementation/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;

  enum State {
    Idle,
    Started,
    InProgress
  };

  volatile State _state;

  void sleepBeforeNextCycle();

  static SurrogateLockerThread*         _slt;

 public:
  // Constructor
  ConcurrentMarkThread(ConcurrentMark* cm);

  static void makeSurrogateLockerThread(TRAPS);
  static SurrogateLockerThread* slt() { return _slt; }

  // Printing
  void print_on(outputStream* st) const;
  void print() const;

  // Total virtual time so far.
  double vtime_accum();
  // Marking virtual time so far
  double vtime_mark_accum();

  ConcurrentMark* cm()     { return _cm; }

  void set_idle()          { assert(_state != Started, "must not be starting a new cycle"); _state = Idle; }
  bool idle()              { return _state == Idle; }
  void set_started()       { assert(_state == Idle, "cycle in progress"); _state = Started; }
  bool started()           { return _state == Started; }
  void set_in_progress()   { assert(_state == Started, "must be starting a cycle"); _state = InProgress; }
  bool in_progress()       { return _state == InProgress; }

  // 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 during_cycle() 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 !idle(); }

  // shutdown
  void stop();
};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARKTHREAD_HPP