/*

 * Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

// Forward decl

class ConcurrentG1RefineThread;

class G1RemSet;

// What to do after a yield:

enum PostYieldAction {

  PYA_continue,  // Continue the traversal

  PYA_restart,   // Restart

  PYA_cancel     // It's been completed by somebody else: cancel.

};

class ConcurrentG1Refine: public CHeapObj {

  ConcurrentG1RefineThread* _cg1rThread;

  volatile jint _pya;

  PostYieldAction _last_pya;

  static bool _enabled;  // Protected by G1ConcRefine_mon.

  unsigned _traversals;

  // Number of cards processed during last refinement traversal.

  unsigned _first_traversal;

  unsigned _last_cards_during;

  // The cache for card refinement.

  bool     _use_cache;

  bool     _def_use_cache;

  size_t _n_periods;

  size_t _total_cards;

  size_t _total_travs;

  unsigned char*  _card_counts;

  unsigned _n_card_counts;

  const jbyte* _ct_bot;

  unsigned* _cur_card_count_histo;

  unsigned* _cum_card_count_histo;

  jbyte**  _hot_cache;

  int      _hot_cache_size;

  int      _n_hot;

  int      _hot_cache_idx;

  // Returns the count of this card after incrementing it.

  int add_card_count(jbyte* card_ptr);

  void print_card_count_histo_range(unsigned* histo, int from, int to,

                                    float& cum_card_pct,

                                    float& cum_travs_pct);

 public:

  ConcurrentG1Refine();

  ~ConcurrentG1Refine();

  void init(); // Accomplish some initialization that has to wait.

  // Enabled Conc refinement, waking up thread if necessary.

  void enable();

  // Returns the number of traversals performed since this refiner was enabled.

  unsigned disable();

  // Requires G1ConcRefine_mon to be held.

  bool enabled() { return _enabled; }

  // Returns only when G1 concurrent refinement has been enabled.

  void wait_for_ConcurrentG1Refine_enabled();

  // Do one concurrent refinement pass over the card table.  Returns "true"

  // if heuristics determine that another pass should be done immediately.

  bool refine();

  // Indicate that an in-progress refinement pass should start over.

  void set_pya_restart();

  // Indicate that an in-progress refinement pass should quit.

  void set_pya_cancel();

  // Get the appropriate post-yield action.  Also sets last_pya.

  PostYieldAction get_pya();

  // The last PYA read by "get_pya".

  PostYieldAction get_last_pya();

  bool do_traversal();

  ConcurrentG1RefineThread* cg1rThread() { return _cg1rThread; }

  // If this is the first entry for the slot, writes into the cache and

  // returns NULL.  If it causes an eviction, returns the evicted pointer.

  // Otherwise, its a cache hit, and returns NULL.

  jbyte* cache_insert(jbyte* card_ptr);

  // Process the cached entries.

  void clean_up_cache(int worker_i, G1RemSet* g1rs);

  // Discard entries in the hot cache.

  void clear_hot_cache() {

    _hot_cache_idx = 0; _n_hot = 0;

  }

  bool hot_cache_is_empty() { return _n_hot == 0; }

  bool use_cache() { return _use_cache; }

  void set_use_cache(bool b) {

    if (b) _use_cache = _def_use_cache;

    else   _use_cache = false;

  }

  void clear_and_record_card_counts();

  void print_final_card_counts();

};