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 * 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.

 *

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#ifndef SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP

#define SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP

#include "gc/g1/g1BufferNodeList.hpp"

#include "gc/g1/g1FreeIdSet.hpp"

#include "gc/shared/ptrQueue.hpp"

#include "memory/allocation.hpp"

class G1DirtyCardQueueSet;

class G1RedirtyCardsQueueSet;

class Thread;

class Monitor;

// A ptrQueue whose elements are "oops", pointers to object heads.

class G1DirtyCardQueue: public PtrQueue {

protected:

  virtual void handle_completed_buffer();

public:

  G1DirtyCardQueue(G1DirtyCardQueueSet* qset);

  // Flush before destroying; queue may be used to capture pending work while

  // doing something else, with auto-flush on completion.

  ~G1DirtyCardQueue();

  // Process queue entries and release resources.

  void flush() { flush_impl(); }

  inline G1DirtyCardQueueSet* dirty_card_qset() const;

  // Compiler support.

  static ByteSize byte_offset_of_index() {

    return PtrQueue::byte_offset_of_index<G1DirtyCardQueue>();

  }

  using PtrQueue::byte_width_of_index;

  static ByteSize byte_offset_of_buf() {

    return PtrQueue::byte_offset_of_buf<G1DirtyCardQueue>();

  }

  using PtrQueue::byte_width_of_buf;

};

class G1DirtyCardQueueSet: public PtrQueueSet {

  Monitor* _cbl_mon;  // Protects the list and count members.

  BufferNode* _completed_buffers_head;

  BufferNode* _completed_buffers_tail;

  // Number of actual cards in the list of completed buffers.

  volatile size_t _num_cards;

  size_t _process_cards_threshold;

  volatile bool _process_completed_buffers;

  void abandon_completed_buffers();

  // Refine the cards in "node" from its index to buffer_size.

  // Stops processing if SuspendibleThreadSet::should_yield() is true.

  // Returns true if the entire buffer was processed, false if there

  // is a pending yield request.  The node's index is updated to exclude

  // the processed elements, e.g. up to the element before processing

  // stopped, or one past the last element if the entire buffer was

  // processed. Increments *total_refined_cards by the number of cards

  // processed and removed from the buffer.

  bool refine_buffer(BufferNode* node, uint worker_id, size_t* total_refined_cards);

  bool mut_process_buffer(BufferNode* node);

  // If the queue contains more cards than configured here, the

  // mutator must start doing some of the concurrent refinement work.

  size_t _max_cards;

  size_t _max_cards_padding;

  static const size_t MaxCardsUnlimited = SIZE_MAX;

  G1FreeIdSet _free_ids;

  // Array of cumulative dirty cards refined by mutator threads.

  // Array has an entry per id in _free_ids.

  size_t* _mutator_refined_cards_counters;

public:

  G1DirtyCardQueueSet(Monitor* cbl_mon, BufferNode::Allocator* allocator);

  ~G1DirtyCardQueueSet();

  // The number of parallel ids that can be claimed to allow collector or

  // mutator threads to do card-processing work.

  static uint num_par_ids();

  static void handle_zero_index_for_thread(Thread* t);

  // Either process the entire buffer and return true, or enqueue the

  // buffer and return false.  If the buffer is completely processed,

  // it can be reused in place.

  bool process_or_enqueue_completed_buffer(BufferNode* node);

  virtual void enqueue_completed_buffer(BufferNode* node);

  // If the number of completed buffers is > stop_at, then remove and

  // return a completed buffer from the list.  Otherwise, return NULL.

  BufferNode* get_completed_buffer(size_t stop_at = 0);

  // The number of cards in completed buffers. Read without synchronization.

  size_t num_cards() const { return _num_cards; }

  // Verify that _num_cards is equal to the sum of actual cards

  // in the completed buffers.

  void verify_num_cards() const NOT_DEBUG_RETURN;

  bool process_completed_buffers() { return _process_completed_buffers; }

  void set_process_completed_buffers(bool x) { _process_completed_buffers = x; }

  // Get/Set the number of cards that triggers log processing.

  // Log processing should be done when the number of cards exceeds the

  // threshold.

  void set_process_cards_threshold(size_t sz) {

    _process_cards_threshold = sz;

  }

  size_t process_cards_threshold() const {

    return _process_cards_threshold;

  }

  static const size_t ProcessCardsThresholdNever = SIZE_MAX;

  // Notify the consumer if the number of buffers crossed the threshold

  void notify_if_necessary();

  void merge_bufferlists(G1RedirtyCardsQueueSet* src);

  G1BufferNodeList take_all_completed_buffers();

  // If there are more than stop_at cards in the completed buffers, pop

  // a buffer, refine its contents, and return true.  Otherwise return

  // false.

  //

  // Stops processing a buffer if SuspendibleThreadSet::should_yield(),

  // returning the incompletely processed buffer to the completed buffer

  // list, for later processing of the remainder.

  //

  // Increments *total_refined_cards by the number of cards processed and

  // removed from the buffer.

  bool refine_completed_buffer_concurrently(uint worker_id,

                                            size_t stop_at,

                                            size_t* total_refined_cards);

  // If a full collection is happening, reset partial logs, and release

  // completed ones: the full collection will make them all irrelevant.

  void abandon_logs();

  // If any threads have partial logs, add them to the global list of logs.

  void concatenate_logs();

  void set_max_cards(size_t m) {

    _max_cards = m;

  }

  size_t max_cards() const {

    return _max_cards;

  }

  void set_max_cards_padding(size_t padding) {

    _max_cards_padding = padding;

  }

  size_t max_cards_padding() const {

    return _max_cards_padding;

  }

  // Total dirty cards refined by mutator threads.

  size_t total_mutator_refined_cards() const;

};

inline G1DirtyCardQueueSet* G1DirtyCardQueue::dirty_card_qset() const {

  return static_cast<G1DirtyCardQueueSet*>(qset());

}

#endif // SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP