/*

 * Copyright (c) 2002, 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.

 *

 */

//

// psPromotionManager is used by a single thread to manage object survival

// during a scavenge. The promotion manager contains thread local data only.

//

// NOTE! Be carefull when allocating the stacks on cheap. If you are going

// to use a promotion manager in more than one thread, the stacks MUST be

// on cheap. This can lead to memory leaks, though, as they are not auto

// deallocated.

//

// FIX ME FIX ME Add a destructor, and don't rely on the user to drain/flush/deallocate!

//

// Move to some global location

#define HAS_BEEN_MOVED 0x1501d01d

// End move to some global location

class MutableSpace;

class PSOldGen;

class ParCompactionManager;

class PSPromotionManager : public CHeapObj {

  friend class PSScavenge;

  friend class PSRefProcTaskExecutor;

 private:

  static PSPromotionManager**         _manager_array;

  static OopStarTaskQueueSet*         _stack_array_depth;

  static OopTaskQueueSet*             _stack_array_breadth;

  static PSOldGen*                    _old_gen;

  static MutableSpace*                _young_space;

  PSYoungPromotionLAB                 _young_lab;

  PSOldPromotionLAB                   _old_lab;

  bool                                _young_gen_is_full;

  bool                                _old_gen_is_full;

  PrefetchQueue                       _prefetch_queue;

  OopStarTaskQueue                    _claimed_stack_depth;

  OverflowTaskQueue<oop>              _claimed_stack_breadth;

  bool                                _depth_first;

  bool                                _totally_drain;

  uint                                _target_stack_size;

  uint                                _array_chunk_size;

  uint                                _min_array_size_for_chunking;

  // Accessors

  static PSOldGen* old_gen()         { return _old_gen; }

  static MutableSpace* young_space() { return _young_space; }

  inline static PSPromotionManager* manager_array(int index);

  template <class T> inline void claim_or_forward_internal_depth(T* p);

  template <class T> inline void claim_or_forward_internal_breadth(T* p);

  // On the task queues we push reference locations as well as

  // partially-scanned arrays (in the latter case, we push an oop to

  // the from-space image of the array and the length on the

  // from-space image indicates how many entries on the array we still

  // need to scan; this is basically how ParNew does partial array

  // scanning too). To be able to distinguish between reference

  // locations and partially-scanned array oops we simply mask the

  // latter oops with 0x01. The next three methods do the masking,

  // unmasking, and checking whether the oop is masked or not. Notice

  // that the signature of the mask and unmask methods looks a bit

  // strange, as they accept and return different types (oop and

  // oop*). This is because of the difference in types between what

  // the task queue holds (oop*) and oops to partially-scanned arrays

  // (oop). We do all the necessary casting in the mask / unmask

  // methods to avoid sprinkling the rest of the code with more casts.

  // These are added to the taskqueue so PS_CHUNKED_ARRAY_OOP_MASK (or any

  // future masks) can't conflict with COMPRESSED_OOP_MASK

#define PS_CHUNKED_ARRAY_OOP_MASK  0x2

  bool is_oop_masked(StarTask p) {

    // If something is marked chunked it's always treated like wide oop*

    return (((intptr_t)(oop*)p) & PS_CHUNKED_ARRAY_OOP_MASK) ==

                                  PS_CHUNKED_ARRAY_OOP_MASK;

  }

  oop* mask_chunked_array_oop(oop obj) {

    assert(!is_oop_masked((oop*) obj), "invariant");

    oop* ret = (oop*) ((uintptr_t)obj | PS_CHUNKED_ARRAY_OOP_MASK);

    assert(is_oop_masked(ret), "invariant");

    return ret;

  }

  oop unmask_chunked_array_oop(StarTask p) {

    assert(is_oop_masked(p), "invariant");

    assert(!p.is_narrow(), "chunked array oops cannot be narrow");

    oop *chunk = (oop*)p;  // cast p to oop (uses conversion operator)

    oop ret = oop((oop*)((uintptr_t)chunk & ~PS_CHUNKED_ARRAY_OOP_MASK));

    assert(!is_oop_masked((oop*) ret), "invariant");

    return ret;

  }

  template <class T> void  process_array_chunk_work(oop obj,

                                                    int start, int end);

  void process_array_chunk(oop old);

  template <class T> void push_depth(T* p) {

    assert(depth_first(), "pre-condition");

    claimed_stack_depth()->push(p);

  }

  void push_breadth(oop o) {

    assert(!depth_first(), "pre-condition");

    claimed_stack_breadth()->push(o);

  }

 protected:

  static OopStarTaskQueueSet* stack_array_depth()   { return _stack_array_depth; }

  static OopTaskQueueSet*     stack_array_breadth() { return _stack_array_breadth; }

 public:

  // Static

  static void initialize();

  static void pre_scavenge();

  static void post_scavenge();

  static PSPromotionManager* gc_thread_promotion_manager(int index);

  static PSPromotionManager* vm_thread_promotion_manager();

  static bool steal_depth(int queue_num, int* seed, StarTask& t) {

    return stack_array_depth()->steal(queue_num, seed, t);

  }

  static bool steal_breadth(int queue_num, int* seed, oop& t) {

    return stack_array_breadth()->steal(queue_num, seed, t);

  }

  PSPromotionManager();

  // Accessors

  OopStarTaskQueue* claimed_stack_depth() {

    return &_claimed_stack_depth;

  }

  OverflowTaskQueue<oop>* claimed_stack_breadth() {

    return &_claimed_stack_breadth;

  }

  bool young_gen_is_full()             { return _young_gen_is_full; }

  bool old_gen_is_full()               { return _old_gen_is_full; }

  void set_old_gen_is_full(bool state) { _old_gen_is_full = state; }

  // Promotion methods

  oop copy_to_survivor_space(oop o, bool depth_first);

  oop oop_promotion_failed(oop obj, markOop obj_mark);

  void reset();

  void flush_labs();

  void drain_stacks(bool totally_drain) {

    if (depth_first()) {

      drain_stacks_depth(totally_drain);

    } else {

      drain_stacks_breadth(totally_drain);

    }

  }

 public:

  void drain_stacks_cond_depth() {

    if (claimed_stack_depth()->size() > _target_stack_size) {

      drain_stacks_depth(false);

    }

  }

  void drain_stacks_depth(bool totally_drain);

  void drain_stacks_breadth(bool totally_drain);

  bool depth_first() const {

    return _depth_first;

  }

  bool stacks_empty() {

    return depth_first() ?

      claimed_stack_depth()->is_empty() :

      claimed_stack_breadth()->is_empty();

  }

  inline void process_popped_location_depth(StarTask p);

  inline void flush_prefetch_queue();

  template <class T> inline void claim_or_forward_depth(T* p);

  template <class T> inline void claim_or_forward_breadth(T* p);

};