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/shared/ptrQueue.hpp"

    29 #include "memory/allocation.hpp"

    30 #include "memory/padded.hpp"

    31 

    32 class G1CardTableEntryClosure;

    33 class G1RedirtyCardsQueue;

    34 class G1RedirtyCardsQueueSet;

    35 

    36 struct G1RedirtyCardsBufferList {

    37   BufferNode* _head;

    38   BufferNode* _tail;

    39   size_t _count;

    40 

    41   G1RedirtyCardsBufferList();

    42   G1RedirtyCardsBufferList(BufferNode* head, BufferNode* tail, size_t count);

    43 };

    44 

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

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

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

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

    49 class G1RedirtyCardsQueueBase {

    50   friend class G1RedirtyCardsQueue;

    51   friend class G1RedirtyCardsQueueSet;

    52 

    53   class LocalQSet : public PtrQueueSet {

    54     G1RedirtyCardsQueueSet* _shared_qset;

    55     G1RedirtyCardsBufferList _buffers;

    56 

    57   public:

    58     LocalQSet(G1RedirtyCardsQueueSet* shared_qset);

    59     ~LocalQSet();

    60 

    61     // Add the buffer to the local list.

    62     virtual void enqueue_completed_buffer(BufferNode* node);

    63 

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

    65     void flush();

    66 

    67     G1RedirtyCardsBufferList take_all_completed_buffers();

    68   };

    69 

    70   G1RedirtyCardsQueueBase(G1RedirtyCardsQueueSet* shared_qset) :

    71     _local_qset(shared_qset) {}

    72 

    73   ~G1RedirtyCardsQueueBase() {}

    74 

    75   LocalQSet _local_qset;

    76 };

    77 

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

    79 class G1RedirtyCardsQueue : private G1RedirtyCardsQueueBase, public PtrQueue {

    80 protected:

    81   virtual void handle_completed_buffer();

    82 

    83 public:

    84   G1RedirtyCardsQueue(G1RedirtyCardsQueueSet* qset);

    85 

    86   // Flushes the queue.

    87   ~G1RedirtyCardsQueue();

    88 

    89   // Flushes all enqueued cards to qset.

    90   void flush();

    91 };

    92 

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

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

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

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

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

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

    99 class G1RedirtyCardsQueueSet : public PtrQueueSet {

   100   DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);

   101   BufferNode::Stack _list;

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

   103   volatile size_t _count;

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

   105   BufferNode* _tail;

   106   DEBUG_ONLY(mutable bool _collecting;)

   107 

   108   typedef G1RedirtyCardsQueueBase::LocalQSet LocalQSet;

   109 

   110   void update_tail(BufferNode* node);

   111 

   112 public:

   113   G1RedirtyCardsQueueSet();

   114   ~G1RedirtyCardsQueueSet();

   115 

   116   using PtrQueueSet::initialize;

   117 

   118   void verify_empty() const NOT_DEBUG_RETURN;

   119 

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

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

   122   virtual void enqueue_completed_buffer(BufferNode* node);

   123   void merge_bufferlist(LocalQSet* src);

   124 

   125   // Processing phase operations.

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

   127   BufferNode* all_completed_buffers() const;

   128   G1RedirtyCardsBufferList take_all_completed_buffers();

   129 };

   130 

   131 #endif // SHARE_GC_G1_G1REDIRTYCARDSQUEUE_HPP