_monitor(NULL),

  _vtime_accum(0.0)

  // Each thread has its own monitor. The i-th thread is responsible for signalling

  // to thread i+1 if the number of buffers in the queue exceeds a threashold for this

  // thread. Monitors are also used to wake up the threads during termination.

  // The 0th worker in notified by mutator threads and has a special monitor.

  // The last worker is used for young gen rset size sampling.

  if (worker_id > 0) {

    _monitor = new Monitor(Mutex::nonleaf, "Refinement monitor", true);

  } else {

    _monitor = DirtyCardQ_CBL_mon;

  }

  initialize();

void ConcurrentG1RefineThread::initialize() {

  if (_worker_id < cg1r()->worker_thread_num()) {

    // Current thread activation threshold

    _threshold = MIN2<int>(cg1r()->thread_threshold_step() * (_worker_id + 1) + cg1r()->green_zone(),

                           cg1r()->yellow_zone());

    // A thread deactivates once the number of buffer reached a deactivation threshold

    _deactivation_threshold = MAX2<int>(_threshold - cg1r()->thread_threshold_step(), cg1r()->green_zone());

  } else {

    set_active(true);

  }

}

void ConcurrentG1RefineThread::run_young_rs_sampling() {

  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

  while(!_should_terminate) {

    _sts.join();

    sample_young_list_rs_lengths();

    _sts.leave();

    if (os::supports_vtime()) {

      _vtime_accum = (os::elapsedVTime() - _vtime_start);

    } else {

      _vtime_accum = 0.0;

    MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

    if (_should_terminate) {

      break;

    }

    _monitor->wait(Mutex::_no_safepoint_check_flag, G1ConcRefineServiceInterval);

  }

}

void ConcurrentG1RefineThread::wait_for_completed_buffers() {

  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

  while (!_should_terminate && !is_active()) {

    _monitor->wait(Mutex::_no_safepoint_check_flag);

  }

}

bool ConcurrentG1RefineThread::is_active() {

  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

  return _worker_id > 0 ? _active : dcqs.process_completed_buffers();

}

void ConcurrentG1RefineThread::activate() {

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

  if (_worker_id > 0) {

    if (G1TraceConcurrentRefinement) {

      DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

      gclog_or_tty->print_cr("G1-Refine-activated worker %d, on threshold %d, current %d",

                             _worker_id, _threshold, (int)dcqs.completed_buffers_num());

    set_active(true);

  } else {

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

    dcqs.set_process_completed(true);

  }

  _monitor->notify();

}

void ConcurrentG1RefineThread::deactivate() {

  MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

  if (_worker_id > 0) {

    if (G1TraceConcurrentRefinement) {

      DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

      gclog_or_tty->print_cr("G1-Refine-deactivated worker %d, off threshold %d, current %d",

                             _worker_id, _deactivation_threshold, (int)dcqs.completed_buffers_num());

    }

    set_active(false);

  } else {

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

    dcqs.set_process_completed(false);

  }

}

void ConcurrentG1RefineThread::run() {

  initialize_in_thread();

  wait_for_universe_init();

  if (_worker_id >= cg1r()->worker_thread_num()) {

    run_young_rs_sampling();

    terminate();

  }

  _vtime_start = os::elapsedVTime();

  while (!_should_terminate) {

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

    // Wait for work

    wait_for_completed_buffers();

    if (_should_terminate) {

      break;

    }

    _sts.join();

    do {

      int curr_buffer_num = (int)dcqs.completed_buffers_num();

      // If the number of the buffers falls down into the yellow zone,

      // that means that the transition period after the evacuation pause has ended.

      if (dcqs.completed_queue_padding() > 0 && curr_buffer_num <= cg1r()->yellow_zone()) {

        dcqs.set_completed_queue_padding(0);

      if (_worker_id > 0 && curr_buffer_num <= _deactivation_threshold) {

      if (_next != NULL && !_next->is_active() && curr_buffer_num > _next->_threshold) {

    } while (dcqs.apply_closure_to_completed_buffer(_worker_id + _worker_id_offset, cg1r()->green_zone()));

    // We can exit the loop above while being active if there was a yield request.

    if (is_active()) {

      deactivate();

    MutexLockerEx x(_monitor, Mutex::_no_safepoint_check_flag);

    _monitor->notify();