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 /*

  * Copyright (c) 2001, 2014, 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_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 */) { }

   // Process queue entries and free resources.

   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, uint worker);

 #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();

   // 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(uint 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(uint 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