1 /*

     2  * Copyright (c) 2001, 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_DIRTYCARDQUEUE_HPP

    26 #define SHARE_GC_G1_DIRTYCARDQUEUE_HPP

    27 

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

    29 #include "memory/allocation.hpp"

    30 

    31 class DirtyCardQueueSet;

    32 class G1FreeIdSet;

    33 class JavaThread;

    34 class Monitor;

    35 

    36 // A closure class for processing card table entries.  Note that we don't

    37 // require these closure objects to be stack-allocated.

    38 class CardTableEntryClosure: public CHeapObj<mtGC> {

    39 public:

    40   // Process the card whose card table entry is "card_ptr".  If returns

    41   // "false", terminate the iteration early.

    42   virtual bool do_card_ptr(jbyte* card_ptr, uint worker_i) = 0;

    43 };

    44 

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

    46 class DirtyCardQueue: public PtrQueue {

    47 public:

    48   DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent = false);

    49 

    50   // Flush before destroying; queue may be used to capture pending work while

    51   // doing something else, with auto-flush on completion.

    52   ~DirtyCardQueue();

    53 

    54   // Process queue entries and release resources.

    55   void flush() { flush_impl(); }

    56 

    57   // Compiler support.

    58   static ByteSize byte_offset_of_index() {

    59     return PtrQueue::byte_offset_of_index<DirtyCardQueue>();

    60   }

    61   using PtrQueue::byte_width_of_index;

    62 

    63   static ByteSize byte_offset_of_buf() {

    64     return PtrQueue::byte_offset_of_buf<DirtyCardQueue>();

    65   }

    66   using PtrQueue::byte_width_of_buf;

    67 

    68 };

    69 

    70 

    71 

    72 class DirtyCardQueueSet: public PtrQueueSet {

    73   DirtyCardQueue _shared_dirty_card_queue;

    74 

    75   // Apply the closure to the elements of "node" from it's index to

    76   // buffer_size.  If all closure applications return true, then

    77   // returns true.  Stops processing after the first closure

    78   // application that returns false, and returns false from this

    79   // function.  If "consume" is true, the node's index is updated to

    80   // exclude the processed elements, e.g. up to the element for which

    81   // the closure returned false.

    82   bool apply_closure_to_buffer(CardTableEntryClosure* cl,

    83                                BufferNode* node,

    84                                bool consume,

    85                                uint worker_i = 0);

    86 

    87   // If there are more than stop_at completed buffers, pop one, apply

    88   // the specified closure to its active elements, and return true.

    89   // Otherwise return false.

    90   //

    91   // A completely processed buffer is freed.  However, if a closure

    92   // invocation returns false, processing is stopped and the partially

    93   // processed buffer (with its index updated to exclude the processed

    94   // elements, e.g. up to the element for which the closure returned

    95   // false) is returned to the completed buffer set.

    96   //

    97   // If during_pause is true, stop_at must be zero, and the closure

    98   // must never return false.

    99   bool apply_closure_to_completed_buffer(CardTableEntryClosure* cl,

   100                                          uint worker_i,

   101                                          size_t stop_at,

   102                                          bool during_pause);

   103 

   104   bool mut_process_buffer(BufferNode* node);

   105 

   106   G1FreeIdSet* _free_ids;

   107 

   108   // The number of completed buffers processed by mutator and rs thread,

   109   // respectively.

   110   jint _processed_buffers_mut;

   111   jint _processed_buffers_rs_thread;

   112 

   113   // Current buffer node used for parallel iteration.

   114   BufferNode* volatile _cur_par_buffer_node;

   115 

   116   void concatenate_log(DirtyCardQueue& dcq);

   117 

   118 public:

   119   DirtyCardQueueSet(bool notify_when_complete = true);

   120   ~DirtyCardQueueSet();

   121 

   122   void initialize(Monitor* cbl_mon,

   123                   BufferNode::Allocator* allocator,

   124                   Mutex* lock,

   125                   bool init_free_ids = false);

   126 

   127   // The number of parallel ids that can be claimed to allow collector or

   128   // mutator threads to do card-processing work.

   129   static uint num_par_ids();

   130 

   131   static void handle_zero_index_for_thread(JavaThread* t);

   132 

   133   // Apply G1RefineCardConcurrentlyClosure to completed buffers until there are stop_at

   134   // completed buffers remaining.

   135   bool refine_completed_buffer_concurrently(uint worker_i, size_t stop_at);

   136 

   137   // Apply the given closure to all completed buffers. The given closure's do_card_ptr

   138   // must never return false. Must only be called during GC.

   139   bool apply_closure_during_gc(CardTableEntryClosure* cl, uint worker_i);

   140 

   141   void reset_for_par_iteration() { _cur_par_buffer_node = completed_buffers_head(); }

   142   // Applies the current closure to all completed buffers, non-consumptively.

   143   // Can be used in parallel, all callers using the iteration state initialized

   144   // by reset_for_par_iteration.

   145   void par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl);

   146 

   147   DirtyCardQueue* shared_dirty_card_queue() {

   148     return &_shared_dirty_card_queue;

   149   }

   150 

   151   // If a full collection is happening, reset partial logs, and ignore

   152   // completed ones: the full collection will make them all irrelevant.

   153   void abandon_logs();

   154 

   155   // If any threads have partial logs, add them to the global list of logs.

   156   void concatenate_logs();

   157 

   158   jint processed_buffers_mut() {

   159     return _processed_buffers_mut;

   160   }

   161   jint processed_buffers_rs_thread() {

   162     return _processed_buffers_rs_thread;

   163   }

   164 

   165 };

   166 

   167 #endif // SHARE_GC_G1_DIRTYCARDQUEUE_HPP