src/hotspot/share/gc/g1/g1ConcurrentMarkThread.hpp

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#ifndef SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP
#define SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP

#include "gc/shared/concurrentGCThread.hpp"

class G1ConcurrentMark;
class G1Policy;

// The concurrent mark thread triggers the various steps of the concurrent marking
// cycle, including various marking cleanup.
class G1ConcurrentMarkThread: public ConcurrentGCThread {
  friend class VMStructs;

  double _vtime_start;  // Initial virtual time.
  double _vtime_accum;  // Accumulated virtual time.

  G1ConcurrentMark* _cm;

  enum ServiceState : uint {
    Idle,
    FullMark,
    UndoMark
  };

  volatile ServiceState _state;

  // Wait for next cycle. Returns the command passed over.
  bool wait_for_next_cycle();

  bool mark_loop_needs_restart() const;

  // Phases and subphases for the full concurrent marking cycle in order.
  //
  // All these methods return true if the marking should be aborted.
  bool phase_clear_cld_claimed_marks();
  bool phase_scan_root_regions();

  bool phase_mark_loop();
  bool subphase_mark_from_roots();
  bool subphase_preclean();
  bool subphase_delay_to_keep_mmu_before_remark();
  bool subphase_remark();

  bool phase_rebuild_and_scrub();
  bool phase_delay_to_keep_mmu_before_cleanup();
  bool phase_cleanup();
  bool phase_clear_bitmap_for_next_mark();

  void concurrent_cycle_start();

  void concurrent_mark_cycle_do();
  void concurrent_undo_cycle_do();

  void concurrent_cycle_end(bool mark_cycle_completed);

  // Delay pauses to meet MMU.
  void delay_to_keep_mmu(bool remark);
  double mmu_delay_end(G1Policy* policy, bool remark);

  void run_service();
  void stop_service();

 public:
  // Constructor
  G1ConcurrentMarkThread(G1ConcurrentMark* cm);

  // Total virtual time so far for this thread and concurrent marking tasks.
  double vtime_accum();
  // Marking virtual time so far this thread and concurrent marking tasks.
  double vtime_mark_accum();

  G1ConcurrentMark* cm() { return _cm; }

  void set_idle();
  void start_full_mark();
  void start_undo_mark();

  bool idle() const;
  // Returns true from the moment a concurrent cycle is
  // initiated (during the concurrent start 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).
  bool in_progress() const;

  bool in_undo_mark() const;

  // Update the perf data counter for concurrent mark.
  void update_threads_cpu_time();
};

#endif // SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP