1 /*

     2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_GC_G1_G1REDIRTYCARDSQUEUE_HPP

    26 #define SHARE_GC_G1_G1REDIRTYCARDSQUEUE_HPP

    27 

    28 #include "gc/g1/g1BufferNodeList.hpp"

    29 #include "gc/shared/ptrQueue.hpp"

    30 #include "memory/allocation.hpp"

    31 #include "memory/padded.hpp"

    32 

    33 class G1CardTableEntryClosure;

    34 class G1RedirtyCardsQueue;

    35 class G1RedirtyCardsQueueSet;

    36 

    37 // Provide G1RedirtyCardsQueue with a thread-local qset.  It provides an

    38 // uncontended staging area for completed buffers, to be flushed to the

    39 // shared qset en masse.  Using the "base from member" idiom so the local

    40 // qset is constructed before being passed to the PtrQueue constructor.

    41 class G1RedirtyCardsQueueBase {

    42   friend class G1RedirtyCardsQueue;

    43   friend class G1RedirtyCardsQueueSet;

    44 

    45   class LocalQSet : public PtrQueueSet {

    46     G1RedirtyCardsQueueSet* _shared_qset;

    47     G1BufferNodeList _buffers;

    48 

    49   public:

    50     LocalQSet(G1RedirtyCardsQueueSet* shared_qset);

    51     ~LocalQSet();

    52 

    53     // Add the buffer to the local list.

    54     virtual void enqueue_completed_buffer(BufferNode* node);

    55 

    56     // Transfer all completed buffers to the shared qset.

    57     void flush();

    58 

    59     G1BufferNodeList take_all_completed_buffers();

    60   };

    61 

    62   G1RedirtyCardsQueueBase(G1RedirtyCardsQueueSet* shared_qset) :

    63     _local_qset(shared_qset) {}

    64 

    65   ~G1RedirtyCardsQueueBase() {}

    66 

    67   LocalQSet _local_qset;

    68 };

    69 

    70 // Worker-local queues of card table entries.

    71 class G1RedirtyCardsQueue : private G1RedirtyCardsQueueBase, public PtrQueue {

    72 protected:

    73   virtual void handle_completed_buffer();

    74 

    75 public:

    76   G1RedirtyCardsQueue(G1RedirtyCardsQueueSet* qset);

    77 

    78   // Flushes the queue.

    79   ~G1RedirtyCardsQueue();

    80 

    81   // Flushes all enqueued cards to qset.

    82   void flush();

    83 };

    84 

    85 // Card table entries to be redirtied and the cards reprocessed later.

    86 // Has two phases, collecting and processing.  During the collecting

    87 // phase buffers are added to the set.  Once collecting is complete and

    88 // processing starts, buffers can no longer be added.  Taking all the

    89 // collected (and processed) buffers reverts back to collecting, allowing

    90 // the set to be reused for another round of redirtying.

    91 class G1RedirtyCardsQueueSet : public PtrQueueSet {

    92   DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);

    93   BufferNode::Stack _list;

    94   DEFINE_PAD_MINUS_SIZE(2, DEFAULT_CACHE_LINE_SIZE, sizeof(size_t));

    95   volatile size_t _entry_count;

    96   DEFINE_PAD_MINUS_SIZE(3, DEFAULT_CACHE_LINE_SIZE, sizeof(BufferNode*));

    97   BufferNode* _tail;

    98   DEBUG_ONLY(mutable bool _collecting;)

    99 

   100   typedef G1RedirtyCardsQueueBase::LocalQSet LocalQSet;

   101 

   102   void update_tail(BufferNode* node);

   103 

   104 public:

   105   G1RedirtyCardsQueueSet(BufferNode::Allocator* allocator);

   106   ~G1RedirtyCardsQueueSet();

   107 

   108   void verify_empty() const NOT_DEBUG_RETURN;

   109 

   110   // Collect buffers.  These functions are thread-safe.

   111   // precondition: Must not be concurrent with buffer processing.

   112   virtual void enqueue_completed_buffer(BufferNode* node);

   113   void merge_bufferlist(LocalQSet* src);

   114 

   115   // Processing phase operations.

   116   // precondition: Must not be concurrent with buffer collection.

   117   BufferNode* all_completed_buffers() const;

   118   G1BufferNodeList take_all_completed_buffers();

   119 };

   120 

   121 #endif // SHARE_GC_G1_G1REDIRTYCARDSQUEUE_HPP