hotspot/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.hpp

/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
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// Move to some global location
#define HAS_BEEN_MOVED 0x1501d01d
// End move to some global location


class MutableSpace;
class PSOldGen;
class ParCompactionManager;
class ObjectStartArray;
class ParallelCompactData;
class ParMarkBitMap;

class ParCompactionManager : public CHeapObj {
  friend class ParallelTaskTerminator;
  friend class ParMarkBitMap;
  friend class PSParallelCompact;
  friend class StealRegionCompactionTask;
  friend class UpdateAndFillClosure;
  friend class RefProcTaskExecutor;

 public:

// ------------------------  Don't putback if not needed
  // Actions that the compaction manager should take.
  enum Action {
    Update,
    Copy,
    UpdateAndCopy,
    CopyAndUpdate,
    VerifyUpdate,
    ResetObjects,
    NotValid
  };
// ------------------------  End don't putback if not needed

 private:
  // 32-bit:  4K * 8 = 32KiB; 64-bit:  8K * 16 = 128KiB
  #define QUEUE_SIZE (1 << NOT_LP64(12) LP64_ONLY(13))
  typedef OverflowTaskQueue<ObjArrayTask, QUEUE_SIZE> ObjArrayTaskQueue;
  typedef GenericTaskQueueSet<ObjArrayTaskQueue>      ObjArrayTaskQueueSet;
  #undef QUEUE_SIZE

  static ParCompactionManager** _manager_array;
  static OopTaskQueueSet*       _stack_array;
  static ObjArrayTaskQueueSet*  _objarray_queues;
  static ObjectStartArray*      _start_array;
  static RegionTaskQueueSet*    _region_array;
  static PSOldGen*              _old_gen;

private:
  OverflowTaskQueue<oop>        _marking_stack;
  ObjArrayTaskQueue             _objarray_stack;

  // Is there a way to reuse the _marking_stack for the
  // saving empty regions?  For now just create a different
  // type of TaskQueue.
  RegionTaskQueue               _region_stack;

#if 1  // does this happen enough to need a per thread stack?
  GrowableArray<Klass*>*        _revisit_klass_stack;
  GrowableArray<DataLayout*>*   _revisit_mdo_stack;
#endif
  static ParMarkBitMap* _mark_bitmap;

  Action _action;

  static PSOldGen* old_gen()             { return _old_gen; }
  static ObjectStartArray* start_array() { return _start_array; }
  static OopTaskQueueSet* stack_array()  { return _stack_array; }

  static void initialize(ParMarkBitMap* mbm);

 protected:
  // Array of tasks.  Needed by the ParallelTaskTerminator.
  static RegionTaskQueueSet* region_array()      { return _region_array; }
  OverflowTaskQueue<oop>*  marking_stack()       { return &_marking_stack; }
  RegionTaskQueue* region_stack()                { return &_region_stack; }

  // Pushes onto the marking stack.  If the marking stack is full,
  // pushes onto the overflow stack.
  void stack_push(oop obj);
  // Do not implement an equivalent stack_pop.  Deal with the
  // marking stack and overflow stack directly.

 public:
  Action action() { return _action; }
  void set_action(Action v) { _action = v; }

  inline static ParCompactionManager* manager_array(int index);

  ParCompactionManager();
  ~ParCompactionManager();

  void allocate_stacks();
  void deallocate_stacks();
  ParMarkBitMap* mark_bitmap() { return _mark_bitmap; }

  // Take actions in preparation for a compaction.
  static void reset();

  // void drain_stacks();

  bool should_update();
  bool should_copy();
  bool should_verify_only();
  bool should_reset_only();

#if 1
  // Probably stays as a growable array
  GrowableArray<Klass*>* revisit_klass_stack() { return _revisit_klass_stack; }
  GrowableArray<DataLayout*>* revisit_mdo_stack() { return _revisit_mdo_stack; }
#endif

  // Save for later processing.  Must not fail.
  inline void push(oop obj) { _marking_stack.push(obj); }
  inline void push_objarray(oop objarray, size_t index);
  inline void push_region(size_t index);

  // Access function for compaction managers
  static ParCompactionManager* gc_thread_compaction_manager(int index);

  static bool steal(int queue_num, int* seed, oop& t) {
    return stack_array()->steal(queue_num, seed, t);
  }

  static bool steal_objarray(int queue_num, int* seed, ObjArrayTask& t) {
    return _objarray_queues->steal(queue_num, seed, t);
  }

  static bool steal(int queue_num, int* seed, size_t& region) {
    return region_array()->steal(queue_num, seed, region);
  }

  // Process tasks remaining on any marking stack
  void follow_marking_stacks();
  inline bool marking_stacks_empty() const;

  // Process tasks remaining on any stack
  void drain_region_stacks();

  // Debugging support
#ifdef ASSERT
  bool stacks_have_been_allocated();
#endif
};

inline ParCompactionManager* ParCompactionManager::manager_array(int index) {
  assert(_manager_array != NULL, "access of NULL manager_array");
  assert(index >= 0 && index <= (int)ParallelGCThreads,
    "out of range manager_array access");
  return _manager_array[index];
}

bool ParCompactionManager::marking_stacks_empty() const {
  return _marking_stack.is_empty() && _objarray_stack.is_empty();
}