src/hotspot/share/gc/g1/g1UncommitRegionTask.hpp

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#ifndef SHARE_GC_G1_G1UNCOMMITREGIONTASK_HPP
#define SHARE_GC_G1_G1UNCOMMITREGIONTASK_HPP

#include "gc/g1/g1ServiceThread.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/ticks.hpp"

class G1UncommitRegionTask : public G1ServiceTask {
  // Each execution of the uncommit task is limited to uncommit at most 256M.
  // This limit is small enough to ensure that the duration of each invocation
  // is short, while still making reasonable progress.
  static const uint UncommitSizeLimit = 256 * M;

  static G1UncommitRegionTask* _instance;
  static void initialize();
  static G1UncommitRegionTask* instance();

  // The _active state is used to prevent the task from being enqueued on the
  // service thread multiple times. If the task is active, a new requst to
  // enqueue it will be ignored.
  bool _active;

  // Members to keep a summary of the current concurrent uncommit
  // work. Used for printing when no more work is available.
  Tickspan _summary_duration;
  uint _summary_region_count;

  G1UncommitRegionTask();
  bool is_active();
  void set_active(bool state);

  void report_execution(Tickspan time, uint regions);
  void report_summary();
  void clear_summary();

public:
  static void enqueue();
  virtual void execute();
};

#endif