/*

 * Copyright (c) 2001, 2015, 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

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 */

#ifndef SHARE_VM_GC_G1_SATBMARKQUEUE_HPP

#define SHARE_VM_GC_G1_SATBMARKQUEUE_HPP

#include "gc/g1/ptrQueue.hpp"

#include "memory/allocation.hpp"

class JavaThread;

class SATBMarkQueueSet;

// Base class for processing the contents of a SATB buffer.

class SATBBufferClosure : public StackObj {

protected:

  ~SATBBufferClosure() { }

public:

  // Process the SATB entries in the designated buffer range.

  virtual void do_buffer(void** buffer, size_t size) = 0;

};

// A PtrQueue whose elements are (possibly stale) pointers to object heads.

class SATBMarkQueue: public PtrQueue {

  friend class SATBMarkQueueSet;

private:

  // Filter out unwanted entries from the buffer.

  void filter();

public:

  SATBMarkQueue(SATBMarkQueueSet* qset, bool permanent = false);

  // Process queue entries and free resources.

  void flush();

  // Apply cl to the active part of the buffer.

  // Prerequisite: Must be at a safepoint.

  void apply_closure_and_empty(SATBBufferClosure* cl);

  // Overrides PtrQueue::should_enqueue_buffer(). See the method's

  // definition for more information.

  virtual bool should_enqueue_buffer();

#ifndef PRODUCT

  // Helpful for debugging

  void print(const char* name);

  static void print(const char* name, void** buf, size_t index, size_t sz);

#endif // PRODUCT

  // Compiler support.

  static ByteSize byte_offset_of_index() {

    return PtrQueue::byte_offset_of_index<SATBMarkQueue>();

  }

  using PtrQueue::byte_width_of_index;

  static ByteSize byte_offset_of_buf() {

    return PtrQueue::byte_offset_of_buf<SATBMarkQueue>();

  }

  using PtrQueue::byte_width_of_buf;

  static ByteSize byte_offset_of_active() {

    return PtrQueue::byte_offset_of_active<SATBMarkQueue>();

  }

  using PtrQueue::byte_width_of_active;

};

class SATBMarkQueueSet: public PtrQueueSet {

  SATBMarkQueue _shared_satb_queue;

#ifdef ASSERT

  void dump_active_states(bool expected_active);

  void verify_active_states(bool expected_active);

#endif // ASSERT

public:

  SATBMarkQueueSet();

  void initialize(Monitor* cbl_mon, Mutex* fl_lock,

                  int process_completed_threshold,

                  Mutex* lock);

  static void handle_zero_index_for_thread(JavaThread* t);

  // Apply "set_active(active)" to all SATB queues in the set. It should be

  // called only with the world stopped. The method will assert that the

  // SATB queues of all threads it visits, as well as the SATB queue

  // set itself, has an active value same as expected_active.

  void set_active_all_threads(bool active, bool expected_active);

  // Filter all the currently-active SATB buffers.

  void filter_thread_buffers();

  // If there exists some completed buffer, pop and process it, and

  // return true.  Otherwise return false.  Processing a buffer

  // consists of applying the closure to the buffer range starting

  // with the first non-NULL entry to the end of the buffer; the

  // leading entries may be NULL due to filtering.

  bool apply_closure_to_completed_buffer(SATBBufferClosure* cl);

#ifndef PRODUCT

  // Helpful for debugging

  void print_all(const char* msg);

#endif // PRODUCT

  SATBMarkQueue* shared_satb_queue() { return &_shared_satb_queue; }

  // If a marking is being abandoned, reset any unprocessed log buffers.

  void abandon_partial_marking();

};

#endif // SHARE_VM_GC_G1_SATBMARKQUEUE_HPP