g1CollectorState.hpp

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#ifndef SHARE_GC_G1_G1COLLECTORSTATE_HPP
#define SHARE_GC_G1_G1COLLECTORSTATE_HPP

#include "gc/g1/g1GCPauseType.hpp"
#include "utilities/globalDefinitions.hpp"

// State of the G1 collection.
class G1CollectorState {
  // 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
  // pause, it is a suggestion that the pause should start a marking
  // cycle by doing the concurrent start work. However, it is possible
  // that the concurrent marking thread is still finishing up the
  // previous marking cycle (e.g., clearing the next marking
  // bitmap). If that is the case we cannot start a new cycle and
  // we'll have to wait for the concurrent marking thread to finish
  // what it is doing. In this case we will postpone the marking cycle
  // initiation decision for the next pause. When we eventually decide
  // to start a cycle, we will set _in_concurrent_start_gc which
  // will stay true until the end of the concurrent start pause doing the
  // concurrent start work.
  volatile bool _in_concurrent_start_gc;

  // At the end of a pause we check the heap occupancy and we decide
  // whether we will start a marking cycle during the next pause. If
  // 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 concurrent start phase work.
  volatile bool _initiate_conc_mark_if_possible;

  // Marking or rebuilding remembered set work is in progress. Set from the end
  // of the concurrent start pause to the end of the Cleanup pause.
  bool _mark_or_rebuild_in_progress;

  // The next bitmap is currently being cleared or about to be cleared. TAMS and bitmap
  // may be out of sync.
  bool _clearing_next_bitmap;

  // Set during a full gc pause.
  bool _in_full_gc;

public:
  G1CollectorState() :
    _in_young_only_phase(true),
    _in_young_gc_before_mixed(false),

    _in_concurrent_start_gc(false),
    _initiate_conc_mark_if_possible(false),

    _mark_or_rebuild_in_progress(false),
    _clearing_next_bitmap(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_concurrent_start_gc(bool v) { _in_concurrent_start_gc = v; }
  void set_in_full_gc(bool v) { _in_full_gc = v; }

  void set_initiate_conc_mark_if_possible(bool v) { _initiate_conc_mark_if_possible = v; }

  void set_mark_or_rebuild_in_progress(bool v) { _mark_or_rebuild_in_progress = v; }
  void set_clearing_next_bitmap(bool v) { _clearing_next_bitmap = 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_concurrent_start_gc() const { return _in_concurrent_start_gc; }

  bool initiate_conc_mark_if_possible() const { return _initiate_conc_mark_if_possible; }

  bool mark_or_rebuild_in_progress() const { return _mark_or_rebuild_in_progress; }
  bool clearing_next_bitmap() const { return _clearing_next_bitmap; }

  // Calculate GC Pause Type from internal state.
  G1GCPauseType young_gc_pause_type(bool concurrent_operation_is_full_mark) const;
};

#endif // SHARE_GC_G1_G1COLLECTORSTATE_HPP