/*

 * Copyright (c) 2001, 2019, 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.

 *

 */

#ifndef SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP

#define SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP

#include "gc/shared/cardTable.hpp"

#include "gc/shared/ptrQueue.hpp"

#include "memory/allocation.hpp"

class G1DirtyCardQueueSet;

class G1FreeIdSet;

class Thread;

class Monitor;

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

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

class G1CardTableEntryClosure: public CHeapObj<mtGC> {

public:

  typedef CardTable::CardValue CardValue;

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

  // "false", terminate the iteration early.

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

};

// 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 fields below.

  BufferNode* _completed_buffers_head;

  BufferNode* _completed_buffers_tail;

  volatile size_t _n_completed_buffers;

  size_t _process_completed_buffers_threshold;

  volatile bool _process_completed_buffers;

  // If true, notify_all on _cbl_mon when the threshold is reached.

  bool _notify_when_complete;

  void assert_completed_buffers_list_len_correct_locked() NOT_DEBUG_RETURN;

  void abandon_completed_buffers();

  // 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(G1CardTableEntryClosure* cl,

                               BufferNode* node,

                               bool consume,

                               uint worker_i = 0);

  // 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(G1CardTableEntryClosure* cl,

                                         uint worker_i,

                                         size_t stop_at,

                                         bool during_pause);

  bool mut_process_buffer(BufferNode* node);

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

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

  size_t _max_completed_buffers;

  size_t _completed_buffers_padding;

  static const size_t MaxCompletedBuffersUnlimited = SIZE_MAX;

  G1FreeIdSet* _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;

public:

  G1DirtyCardQueueSet(bool notify_when_complete = true);

  ~G1DirtyCardQueueSet();

  void initialize(Monitor* cbl_mon,

                  BufferNode::Allocator* allocator,

                  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(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 buffers in the list.  Racy...

  size_t completed_buffers_num() const { return _n_completed_buffers; }

  bool process_completed_buffers() { return _process_completed_buffers; }

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

  // Get/Set the number of completed buffers that triggers log processing.

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

  // threshold.

  void set_process_completed_buffers_threshold(size_t sz) {

    _process_completed_buffers_threshold = sz;

  }

  size_t process_completed_buffers_threshold() const {

    return _process_completed_buffers_threshold;

  }

  static const size_t ProcessCompletedBuffersThresholdNever = SIZE_MAX;

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

  void notify_if_necessary();

  void merge_bufferlists(G1DirtyCardQueueSet* src);

  // Apply G1RefineCardConcurrentlyClosure to completed buffers until there are stop_at

  // completed buffers remaining.

  bool refine_completed_buffer_concurrently(uint worker_i, size_t stop_at);

  // Apply the given closure to all completed buffers. The given closure's do_card_ptr

  // must never return false. Must only be called during GC.

  bool apply_closure_during_gc(G1CardTableEntryClosure* cl, uint worker_i);

  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(G1CardTableEntryClosure* cl);

  // 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_completed_buffers(size_t m) {

    _max_completed_buffers = m;

  }

  size_t max_completed_buffers() const {

    return _max_completed_buffers;

  }

  void set_completed_buffers_padding(size_t padding) {

    _completed_buffers_padding = padding;

  }

  size_t completed_buffers_padding() const {

    return _completed_buffers_padding;

  }

  jint processed_buffers_mut() {

    return _processed_buffers_mut;

  }

  jint processed_buffers_rs_thread() {

    return _processed_buffers_rs_thread;

  }

};

inline G1DirtyCardQueueSet* G1DirtyCardQueue::dirty_card_qset() const {

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

}

#endif // SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP