/*

 * Copyright (c) 2005, 2015, 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.

 *

 */

#include "memory/allocation.hpp"

#include "utilities/stack.hpp"

class MutableSpace;

class PSOldGen;

class ParCompactionManager;

class ObjectStartArray;

class ParallelCompactData;

class ParMarkBitMap;

class ParCompactionManager : public CHeapObj<mtGC> {

  friend class ParallelTaskTerminator;

  friend class ParMarkBitMap;

  friend class PSParallelCompact;

  friend class StealRegionCompactionTask;

  friend class UpdateAndFillClosure;

  friend class RefProcTaskExecutor;

  friend class IdleGCTask;

 public:

// ------------------------  Don't putback if not needed

  // Actions that the compaction manager should take.

  enum Action {

    Update,

    Copy,

    UpdateAndCopy,

    CopyAndUpdate,

    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, mtGC, QUEUE_SIZE> ObjArrayTaskQueue;

  typedef GenericTaskQueueSet<ObjArrayTaskQueue, mtGC>      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, mtGC>        _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;

  static RegionTaskQueue**     _region_list;

  // Index in _region_list for current _region_stack.

  uint _region_stack_index;

  // Indexes of recycled region stacks/overflow stacks

  // Stacks of regions to be compacted are embedded in the tasks doing

  // the compaction.  A thread that executes the task extracts the

  // region stack and drains it.  These threads keep these region

  // stacks for use during compaction task stealing.  If a thread

  // gets a second draining task, it pushed its current region stack

  // index into the array _recycled_stack_index and gets a new

  // region stack from the task.  A thread that is executing a

  // compaction stealing task without ever having executing a

  // draining task, will get a region stack from _recycled_stack_index.

  //

  // Array of indexes into the array of region stacks.

  static uint*                    _recycled_stack_index;

  // The index into _recycled_stack_index of the last region stack index

  // pushed.  If -1, there are no entries into _recycled_stack_index.

  static int                      _recycled_top;

  // The index into _recycled_stack_index of the last region stack index

  // popped.  If -1, there has not been any entry popped.

  static int                      _recycled_bottom;

  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, mtGC>*  marking_stack()       { return &_marking_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; }

  RegionTaskQueue* region_stack()                { return _region_stack; }

  void set_region_stack(RegionTaskQueue* v)       { _region_stack = v; }

  inline static ParCompactionManager* manager_array(int index);

  inline static RegionTaskQueue* region_list(int index) {

    return _region_list[index];

  }

  uint region_stack_index() { return _region_stack_index; }

  void set_region_stack_index(uint v) { _region_stack_index = v; }

  // Pop and push unique reusable stack index

  static int pop_recycled_stack_index();

  static void push_recycled_stack_index(uint v);

  static void reset_recycled_stack_index() {

    _recycled_bottom = _recycled_top = -1;

  }

  ParCompactionManager();

  ~ParCompactionManager();

  // Pushes onto the region stack at the given index.  If the

  // region stack is full,

  // pushes onto the region overflow stack.

  static void region_list_push(uint stack_index, size_t region_index);

  static void verify_region_list_empty(uint stack_index);

  ParMarkBitMap* mark_bitmap() { return _mark_bitmap; }

  // void drain_stacks();

  bool should_update();

  bool should_copy();

  // Save for later processing.  Must not fail.

  inline void push(oop obj);

  inline void push_objarray(oop objarray, size_t index);

  inline void push_region(size_t index);

  // Check mark and maybe push on marking stack.

  template <typename T> inline void mark_and_push(T* p);

  inline void follow_klass(Klass* klass);

  void follow_class_loader(ClassLoaderData* klass);

  // Access function for compaction managers

  static ParCompactionManager* gc_thread_compaction_manager(int index);

  static bool steal(int queue_num, int* seed, oop& t);

  static bool steal_objarray(int queue_num, int* seed, ObjArrayTask& t);

  static bool steal(int queue_num, int* seed, size_t& 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();

  void follow_contents(oop obj);

  void follow_contents(objArrayOop array, int index);

  void update_contents(oop obj);

  class MarkAndPushClosure: public ExtendedOopClosure {

   private:

    ParCompactionManager* _compaction_manager;

   public:

    MarkAndPushClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }

    template <typename T> void do_oop_nv(T* p);

    virtual void do_oop(oop* p);

    virtual void do_oop(narrowOop* p);

    // This closure provides its own oop verification code.

    debug_only(virtual bool should_verify_oops() { return false; })

  };

  class FollowStackClosure: public VoidClosure {

   private:

    ParCompactionManager* _compaction_manager;

   public:

    FollowStackClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }

    virtual void do_void();

  };

  // The one and only place to start following the classes.

  // Should only be applied to the ClassLoaderData klasses list.

  class FollowKlassClosure : public KlassClosure {

   private:

    MarkAndPushClosure* _mark_and_push_closure;

   public:

    FollowKlassClosure(MarkAndPushClosure* mark_and_push_closure) :

        _mark_and_push_closure(mark_and_push_closure) { }

    void do_klass(Klass* klass);

  };

};

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();

}