1 /*
   2  * Copyright (c) 2001, 2016, 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.
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  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_DIRTYCARDQUEUE_HPP
  26 #define SHARE_VM_GC_G1_DIRTYCARDQUEUE_HPP
  27 
  28 #include "gc/shared/ptrQueue.hpp"
  29 #include "memory/allocation.hpp"
  30 
  31 class FreeIdSet;
  32 class DirtyCardQueueSet;
  33 
  34 // A closure class for processing card table entries.  Note that we don't
  35 // require these closure objects to be stack-allocated.
  36 class CardTableEntryClosure: public CHeapObj<mtGC> {
  37 public:
  38   // Process the card whose card table entry is "card_ptr".  If returns
  39   // "false", terminate the iteration early.
  40   virtual bool do_card_ptr(jbyte* card_ptr, uint worker_i) = 0;
  41 };
  42 
  43 // A ptrQueue whose elements are "oops", pointers to object heads.
  44 class DirtyCardQueue: public PtrQueue {
  45 public:
  46   DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent = false);
  47 
  48   // Flush before destroying; queue may be used to capture pending work while
  49   // doing something else, with auto-flush on completion.
  50   ~DirtyCardQueue();
  51 
  52   // Process queue entries and release resources.
  53   void flush() { flush_impl(); }
  54 
  55   void **get_buf() { return _buf;}
  56   size_t get_index() { return _index;}
  57   void reinitialize() { _buf = 0; _sz = 0; _index = 0;}
  58 
  59   // Compiler support.
  60   static ByteSize byte_offset_of_index() {
  61     return PtrQueue::byte_offset_of_index<DirtyCardQueue>();
  62   }
  63   using PtrQueue::byte_width_of_index;
  64 
  65   static ByteSize byte_offset_of_buf() {
  66     return PtrQueue::byte_offset_of_buf<DirtyCardQueue>();
  67   }
  68   using PtrQueue::byte_width_of_buf;
  69 
  70 };
  71 
  72 
  73 
  74 class DirtyCardQueueSet: public PtrQueueSet {
  75   // The closure used in mut_process_buffer().
  76   CardTableEntryClosure* _mut_process_closure;
  77 
  78   DirtyCardQueue _shared_dirty_card_queue;
  79 
  80   // Apply the closure to the elements of "node" from it's index to
  81   // buffer_size.  If all closure applications return true, then
  82   // returns true.  Stops processing after the first closure
  83   // application that returns false, and returns false from this
  84   // function.  If "consume" is true, the node's index is updated to
  85   // exclude the processed elements, e.g. up to the element for which
  86   // the closure returned false.
  87   bool apply_closure_to_buffer(CardTableEntryClosure* cl,
  88                                BufferNode* node,
  89                                bool consume,
  90                                uint worker_i = 0);
  91 
  92   bool mut_process_buffer(BufferNode* node);
  93 
  94   // Protected by the _cbl_mon.
  95   FreeIdSet* _free_ids;
  96 
  97   // The number of completed buffers processed by mutator and rs thread,
  98   // respectively.
  99   jint _processed_buffers_mut;
 100   jint _processed_buffers_rs_thread;
 101 
 102   // Current buffer node used for parallel iteration.
 103   BufferNode* volatile _cur_par_buffer_node;
 104 
 105   void concatenate_log(DirtyCardQueue& dcq);
 106 
 107 public:
 108   DirtyCardQueueSet(bool notify_when_complete = true);
 109 
 110   void initialize(CardTableEntryClosure* cl,
 111                   Monitor* cbl_mon,
 112                   Mutex* fl_lock,
 113                   int process_completed_threshold,
 114                   int max_completed_queue,
 115                   Mutex* lock,
 116                   DirtyCardQueueSet* fl_owner,
 117                   bool init_free_ids = false);
 118 
 119   // The number of parallel ids that can be claimed to allow collector or
 120   // mutator threads to do card-processing work.
 121   static uint num_par_ids();
 122 
 123   static void handle_zero_index_for_thread(JavaThread* t);
 124 
 125   // If there are more than stop_at completed buffers, pop one, apply
 126   // the specified closure to its active elements, and return true.
 127   // Otherwise return false.
 128   //
 129   // A completely processed buffer is freed.  However, if a closure
 130   // invocation returns false, processing is stopped and the partially
 131   // processed buffer (with its index updated to exclude the processed
 132   // elements, e.g. up to the element for which the closure returned
 133   // false) is returned to the completed buffer set.
 134   //
 135   // If during_pause is true, stop_at must be zero, and the closure
 136   // must never return false.
 137   bool apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
 138                                          uint worker_i,
 139                                          size_t stop_at,
 140                                          bool during_pause);
 141 
 142   BufferNode* get_completed_buffer(size_t stop_at);
 143 
 144   void reset_for_par_iteration() { _cur_par_buffer_node = _completed_buffers_head; }
 145   // Applies the current closure to all completed buffers, non-consumptively.
 146   // Can be used in parallel, all callers using the iteration state initialized
 147   // by reset_for_par_iteration.
 148   void par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl);
 149 
 150   DirtyCardQueue* shared_dirty_card_queue() {
 151     return &_shared_dirty_card_queue;
 152   }
 153 
 154   // Deallocate any completed log buffers
 155   void clear();
 156 
 157   // If a full collection is happening, reset partial logs, and ignore
 158   // completed ones: the full collection will make them all irrelevant.
 159   void abandon_logs();
 160 
 161   // If any threads have partial logs, add them to the global list of logs.
 162   void concatenate_logs();
 163   void clear_n_completed_buffers() { _n_completed_buffers = 0;}
 164 
 165   jint processed_buffers_mut() {
 166     return _processed_buffers_mut;
 167   }
 168   jint processed_buffers_rs_thread() {
 169     return _processed_buffers_rs_thread;
 170   }
 171 
 172 };
 173 
 174 #endif // SHARE_VM_GC_G1_DIRTYCARDQUEUE_HPP