// State of the G1 collection.

  // Indicates whether we are in the phase where we do partial gcs that only contain

  // the young generation. Not set while _in_full_gc is set.

  bool _in_young_only_phase;

  // Indicates whether we are in the last young gc before the mixed gc phase. This GC

  // is required to keep pause time requirements.

  bool _in_young_gc_before_mixed;

  // If _initiate_conc_mark_if_possible is set at the beginning of a

  // to start a cycle, we will set _in_initial_mark_gc which

  // will stay true until the end of the initial-mark pause doing the

  volatile bool _in_initial_mark_gc;

  // we decide that we want to do that, set this parameter. This parameter will

  // stay set until the beginning of a subsequent pause (not necessarily

  // the next one) when we decide that we will indeed start a marking cycle and

  // do the initial-mark work.

  // Marking or rebuilding remembered set work is in progress. Set from the end

  // of the initial mark pause to the end of the Cleanup pause.

  bool _mark_or_rebuild_in_progress;

  // Set during a full gc pause.

  bool _in_full_gc;

public:

  G1CollectorState() :

    _in_young_only_phase(true),

    _in_young_gc_before_mixed(false),

    _in_initial_mark_gc(false),

    _initiate_conc_mark_if_possible(false),

    _mark_or_rebuild_in_progress(false),

    _in_full_gc(false) { }

  // Phase setters

  void set_in_young_only_phase(bool v) { _in_young_only_phase = v; }

  // Pause setters

  void set_in_young_gc_before_mixed(bool v) { _in_young_gc_before_mixed = v; }

  void set_in_initial_mark_gc(bool v) { _in_initial_mark_gc = v; }

  void set_in_full_gc(bool v) { _in_full_gc = v; }

  void set_mark_or_rebuild_in_progress(bool v) { _mark_or_rebuild_in_progress = v; }

  // Phase getters

  bool in_young_only_phase() const { return _in_young_only_phase && !_in_full_gc; }

  bool in_mixed_phase() const { return !in_young_only_phase() && !_in_full_gc; }

  // Specific pauses

  bool in_young_gc_before_mixed() const { return _in_young_gc_before_mixed; }

  bool in_full_gc() const { return _in_full_gc; }

  bool in_initial_mark_gc() const { return _in_initial_mark_gc; }

  bool mark_or_rebuild_in_progress() const { return _mark_or_rebuild_in_progress; }

    if (in_initial_mark_gc()) {

    } else if (mark_or_rebuild_in_progress()) {

      return DuringMarkOrRebuild;

    } else if (in_young_only_phase()) {