/*

 * Copyright (c) 2001, 2012, 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_IMPLEMENTATION_G1_SATBQUEUE_HPP

#define SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP

#include "gc_implementation/g1/ptrQueue.hpp"

class ObjectClosure;

class JavaThread;

class SATBMarkQueueSet;

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

class ObjPtrQueue: public PtrQueue {

  friend class SATBMarkQueueSet;

private:

  // Filter out unwanted entries from the buffer.

  void filter();

  // Apply the closure to all elements.

  void apply_closure(ObjectClosure* cl);

  // Apply the closure to all elements and empty the buffer;

  void apply_closure_and_empty(ObjectClosure* cl);

  // Apply the closure to all elements of "buf", down to "index" (inclusive.)

  static void apply_closure_to_buffer(ObjectClosure* cl,

                                      void** buf, size_t index, size_t sz);

public:

  ObjPtrQueue(PtrQueueSet* qset, bool perm = false) :

    // SATB queues are only active during marking cycles. We create

    // them with their active field set to false. If a thread is

    // created during a cycle and its SATB queue needs to be activated

    // before the thread starts running, we'll need to set its active

    // field to true. This is done in JavaThread::initialize_queues().

    PtrQueue(qset, perm, false /* active */) { }

  // Overrides PtrQueue::flush() so that it can filter the buffer

  // before it is flushed.

  virtual void flush();

  // 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

  void verify_oops_in_buffer() NOT_DEBUG_RETURN;

};

class SATBMarkQueueSet: public PtrQueueSet {

  ObjectClosure* _closure;

  ObjectClosure** _par_closures;  // One per ParGCThread.

  ObjPtrQueue _shared_satb_queue;

  // Utility function to support sequential and parallel versions.  If

  // "par" is true, then "worker" is the par thread id; if "false", worker

  // is ignored.

  bool apply_closure_to_completed_buffer_work(bool par, int worker);

#ifdef ASSERT

  void dump_active_values(JavaThread* first, 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(b)" to all Java threads' SATB queues. 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 b, bool expected_active);

  // Filter all the currently-active SATB buffers.

  void filter_thread_buffers();

  // Register "blk" as "the closure" for all queues.  Only one such closure

  // is allowed.  The "apply_closure_to_completed_buffer" method will apply

  // this closure to a completed buffer, and "iterate_closure_all_threads"

  // applies it to partially-filled buffers (the latter should only be done

  // with the world stopped).

  void set_closure(ObjectClosure* closure);

  // Set the parallel closures: pointer is an array of pointers to

  // closures, one for each parallel GC thread.

  void set_par_closure(int i, ObjectClosure* closure);

  // Apply the registered closure to all entries on each

  // currently-active buffer and then empty the buffer. It should only

  // be called serially and at a safepoint.

  void iterate_closure_all_threads();

  // Parallel version of the above.

  void par_iterate_closure_all_threads(int worker);

  // If there exists some completed buffer, pop it, then apply the

  // registered closure to all its elements, and return true.  If no

  // completed buffers exist, return false.

  bool apply_closure_to_completed_buffer() {

    return apply_closure_to_completed_buffer_work(false, 0);

  }

  // Parallel version of the above.

  bool par_apply_closure_to_completed_buffer(int worker) {

    return apply_closure_to_completed_buffer_work(true, worker);

  }

  // Apply the given closure on enqueued and currently-active buffers

  // respectively. Both methods are read-only, i.e., they do not

  // modify any of the buffers.

  void iterate_completed_buffers_read_only(ObjectClosure* cl);

  void iterate_thread_buffers_read_only(ObjectClosure* cl);

#ifndef PRODUCT

  // Helpful for debugging

  void print_all(const char* msg);

#endif // PRODUCT

  ObjPtrQueue* 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_IMPLEMENTATION_G1_SATBQUEUE_HPP