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 * Copyright (c) 2001, 2017, 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.

 *

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#ifndef SHARE_VM_GC_G1_DIRTYCARDQUEUE_HPP

#define SHARE_VM_GC_G1_DIRTYCARDQUEUE_HPP

#include "gc/g1/ptrQueue.hpp"

#include "memory/allocation.hpp"

class FreeIdSet;

class DirtyCardQueueSet;

// A closure class for processing card table entries.  Note that we don't

// require these closure objects to be stack-allocated.

class CardTableEntryClosure: public CHeapObj<mtGC> {

public:

  // Process the card whose card table entry is "card_ptr".  If returns

  // "false", terminate the iteration early.

  virtual bool do_card_ptr(jbyte* card_ptr, uint worker_i) = 0;

};

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

class DirtyCardQueue: public PtrQueue {

public:

  DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent = false);

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

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

  ~DirtyCardQueue();

  // Process queue entries and release resources.

  void flush() { flush_impl(); }

  // Compiler support.

  static ByteSize byte_offset_of_index() {

    return PtrQueue::byte_offset_of_index<DirtyCardQueue>();

  }

  using PtrQueue::byte_width_of_index;

  static ByteSize byte_offset_of_buf() {

    return PtrQueue::byte_offset_of_buf<DirtyCardQueue>();

  }

  using PtrQueue::byte_width_of_buf;

};

class DirtyCardQueueSet: public PtrQueueSet {

  // The closure used in mut_process_buffer().

  CardTableEntryClosure* _mut_process_closure;

  DirtyCardQueue _shared_dirty_card_queue;

  // Apply the closure to the elements of "node" from it's index to

  // buffer_size.  If all closure applications return true, then

  // returns true.  Stops processing after the first closure

  // application that returns false, and returns false from this

  // function.  If "consume" is true, the node's index is updated to

  // exclude the processed elements, e.g. up to the element for which

  // the closure returned false.

  bool apply_closure_to_buffer(CardTableEntryClosure* cl,

                               BufferNode* node,

                               bool consume,

                               uint worker_i = 0);

  bool mut_process_buffer(BufferNode* node);

  // Protected by the _cbl_mon.

  FreeIdSet* _free_ids;

  // The number of completed buffers processed by mutator and rs thread,

  // respectively.

  jint _processed_buffers_mut;

  jint _processed_buffers_rs_thread;

  // Current buffer node used for parallel iteration.

  BufferNode* volatile _cur_par_buffer_node;

  void concatenate_log(DirtyCardQueue& dcq);

public:

  DirtyCardQueueSet(bool notify_when_complete = true);

  void initialize(CardTableEntryClosure* cl,

                  Monitor* cbl_mon,

                  Mutex* fl_lock,

                  int process_completed_threshold,

                  int max_completed_queue,

                  Mutex* lock,

                  DirtyCardQueueSet* fl_owner,

                  bool init_free_ids = false);

  // 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(JavaThread* t);

  // If there are more than stop_at completed buffers, pop one, apply

  // the specified closure to its active elements, and return true.

  // Otherwise return false.

  //

  // A completely processed buffer is freed.  However, if a closure

  // invocation returns false, processing is stopped and the partially

  // processed buffer (with its index updated to exclude the processed

  // elements, e.g. up to the element for which the closure returned

  // false) is returned to the completed buffer set.

  //

  // If during_pause is true, stop_at must be zero, and the closure

  // must never return false.

  bool apply_closure_to_completed_buffer(CardTableEntryClosure* cl,

                                         uint worker_i,

                                         size_t stop_at,

                                         bool during_pause);

  BufferNode* get_completed_buffer(size_t stop_at);

  void reset_for_par_iteration() { _cur_par_buffer_node = _completed_buffers_head; }

  // Applies the current closure to all completed buffers, non-consumptively.

  // Can be used in parallel, all callers using the iteration state initialized

  // by reset_for_par_iteration.

  void par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl);

  DirtyCardQueue* shared_dirty_card_queue() {

    return &_shared_dirty_card_queue;

  }

  // Deallocate any completed log buffers

  void clear();

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

  // 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 clear_n_completed_buffers() { _n_completed_buffers = 0;}

  jint processed_buffers_mut() {

    return _processed_buffers_mut;

  }

  jint processed_buffers_rs_thread() {

    return _processed_buffers_rs_thread;

  }

};

#endif // SHARE_VM_GC_G1_DIRTYCARDQUEUE_HPP