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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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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#ifndef SHARE_GC_G1_G1SERVICETHREAD_HPP
#define SHARE_GC_G1_G1SERVICETHREAD_HPP

#include "gc/shared/concurrentGCThread.hpp"

// The G1ServiceThread is used to do a number of different task:
//   - re-assess the validity of the prediction for the
//     remembered set lengths of the young generation.
//   - check if a periodic GC should be scheduled.
class G1ServiceThread: public ConcurrentGCThread {
private:
  Monitor _monitor;

  double _last_periodic_gc_attempt_s;

  double _vtime_accum;  // Accumulated virtual time.

  // Sample the current length of remembered sets for young.
  //
  // At the end of the GC G1 determines the length of the young gen based on
  // how much time the next GC can take, and when the next GC may occur
  // according to the MMU.
  //
  // The assumption is that a significant part of the GC is spent on scanning
  // the remembered sets (and many other components), so this thread constantly
  // reevaluates the prediction for the remembered set scanning costs, and potentially
  // G1Policy resizes the young gen. This may do a premature GC or even
  // increase the young gen size to keep pause time length goal.
  void sample_young_list_rs_length();

  void run_service();
  void check_for_periodic_gc();

  void stop_service();

  void sleep_before_next_cycle();

  bool should_start_periodic_gc();

public:
  G1ServiceThread();
  double vtime_accum() { return _vtime_accum; }
};

#endif // SHARE_GC_G1_G1SERVICETHREAD_HPP