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
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  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
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  24 
  25 #ifndef SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP
  26 #define SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP
  27 
  28 #include "gc/shared/ptrQueue.hpp"
  29 #include "memory/allocation.hpp"
  30 
  31 class G1CardTableEntryClosure;
  32 class G1DirtyCardQueueSet;
  33 class G1FreeIdSet;
  34 class G1RedirtyCardsQueueSet;
  35 class Thread;
  36 class Monitor;
  37 
  38 // A ptrQueue whose elements are "oops", pointers to object heads.
  39 class G1DirtyCardQueue: public PtrQueue {
  40 protected:
  41   virtual void handle_completed_buffer();
  42 
  43 public:
  44   G1DirtyCardQueue(G1DirtyCardQueueSet* qset);
  45 
  46   // Flush before destroying; queue may be used to capture pending work while
  47   // doing something else, with auto-flush on completion.
  48   ~G1DirtyCardQueue();
  49 
  50   // Process queue entries and release resources.
  51   void flush() { flush_impl(); }
  52 
  53   inline G1DirtyCardQueueSet* dirty_card_qset() const;
  54 
  55   // Compiler support.
  56   static ByteSize byte_offset_of_index() {
  57     return PtrQueue::byte_offset_of_index<G1DirtyCardQueue>();
  58   }
  59   using PtrQueue::byte_width_of_index;
  60 
  61   static ByteSize byte_offset_of_buf() {
  62     return PtrQueue::byte_offset_of_buf<G1DirtyCardQueue>();
  63   }
  64   using PtrQueue::byte_width_of_buf;
  65 
  66 };
  67 
  68 class G1DirtyCardQueueSet: public PtrQueueSet {
  69   Monitor* _cbl_mon;  // Protects the fields below.
  70   BufferNode* _completed_buffers_head;
  71   BufferNode* _completed_buffers_tail;
  72 
  73   // Number of actual entries in the list of completed buffers.
  74   volatile size_t _num_entries_in_completed_buffers;
  75 
  76   size_t _process_completed_buffers_threshold;
  77   volatile bool _process_completed_buffers;
  78 
  79   // If true, notify_all on _cbl_mon when the threshold is reached.
  80   bool _notify_when_complete;
  81 
  82   void abandon_completed_buffers();
  83 
  84   // Apply the closure to the elements of "node" from it's index to
  85   // buffer_size.  If all closure applications return true, then
  86   // returns true.  Stops processing after the first closure
  87   // application that returns false, and returns false from this
  88   // function.  The node's index is updated to exclude the processed
  89   // elements, e.g. up to the element for which the closure returned
  90   // false, or one past the last element if the closure always
  91   // returned true.
  92   bool apply_closure_to_buffer(G1CardTableEntryClosure* cl,
  93                                BufferNode* node,
  94                                uint worker_i = 0);
  95 
  96   // If there are more than stop_at completed buffers, pop one, apply
  97   // the specified closure to its active elements, and return true.
  98   // Otherwise return false.
  99   //
 100   // A completely processed buffer is freed.  However, if a closure
 101   // invocation returns false, processing is stopped and the partially
 102   // processed buffer (with its index updated to exclude the processed
 103   // elements, e.g. up to the element for which the closure returned
 104   // false) is returned to the completed buffer set.
 105   //
 106   // If during_pause is true, stop_at must be zero, and the closure
 107   // must never return false.
 108   bool apply_closure_to_completed_buffer(G1CardTableEntryClosure* cl,
 109                                          uint worker_i,
 110                                          size_t stop_at,
 111                                          bool during_pause);
 112 
 113   bool mut_process_buffer(BufferNode* node);
 114 
 115   // If the queue contains more buffers than configured here, the
 116   // mutator must start doing some of the concurrent refinement work,
 117   size_t _max_completed_buffers;
 118   size_t _completed_buffers_padding;
 119   static const size_t MaxCompletedBuffersUnlimited = SIZE_MAX;
 120 
 121   G1FreeIdSet* _free_ids;
 122 
 123   // The number of completed buffers processed by mutator and rs thread,
 124   // respectively.
 125   jint _processed_buffers_mut;
 126   jint _processed_buffers_rs_thread;
 127 
 128 public:
 129   G1DirtyCardQueueSet(bool notify_when_complete = true);
 130   ~G1DirtyCardQueueSet();
 131 
 132   void initialize(Monitor* cbl_mon, BufferNode::Allocator* allocator);
 133 
 134   // The number of parallel ids that can be claimed to allow collector or
 135   // mutator threads to do card-processing work.
 136   static uint num_par_ids();
 137 
 138   static void handle_zero_index_for_thread(Thread* t);
 139 
 140   // Either process the entire buffer and return true, or enqueue the
 141   // buffer and return false.  If the buffer is completely processed,
 142   // it can be reused in place.
 143   bool process_or_enqueue_completed_buffer(BufferNode* node);
 144 
 145   virtual void enqueue_completed_buffer(BufferNode* node);
 146 
 147   // If the number of completed buffers is > stop_at, then remove and
 148   // return a completed buffer from the list.  Otherwise, return NULL.
 149   BufferNode* get_completed_buffer(size_t stop_at = 0);
 150 
 151   // The number of buffers in the list. Derived as an approximation from the number
 152   // of entries in the buffers. Racy.
 153   size_t num_completed_buffers() const {
 154     return (num_entries_in_completed_buffers() + buffer_size() - 1) / buffer_size();
 155   }
 156   // The number of entries in completed buffers. Read without synchronization.
 157   size_t num_entries_in_completed_buffers() const { return _num_entries_in_completed_buffers; }
 158 
 159   // Verify that _num_entries_in_completed_buffers is equal to the sum of actual entries
 160   // in the completed buffers.
 161   void verify_num_entries_in_completed_buffers() const NOT_DEBUG_RETURN;
 162 
 163   bool process_completed_buffers() { return _process_completed_buffers; }
 164   void set_process_completed_buffers(bool x) { _process_completed_buffers = x; }
 165 
 166   // Get/Set the number of completed buffers that triggers log processing.
 167   // Log processing should be done when the number of buffers exceeds the
 168   // threshold.
 169   void set_process_completed_buffers_threshold(size_t sz) {
 170     _process_completed_buffers_threshold = sz;
 171   }
 172   size_t process_completed_buffers_threshold() const {
 173     return _process_completed_buffers_threshold;
 174   }
 175   static const size_t ProcessCompletedBuffersThresholdNever = SIZE_MAX;
 176 
 177   // Notify the consumer if the number of buffers crossed the threshold
 178   void notify_if_necessary();
 179 
 180   void merge_bufferlists(G1RedirtyCardsQueueSet* src);
 181 
 182   // Apply G1RefineCardConcurrentlyClosure to completed buffers until there are stop_at
 183   // completed buffers remaining.
 184   bool refine_completed_buffer_concurrently(uint worker_i, size_t stop_at);
 185 
 186   // Apply the given closure to all completed buffers. The given closure's do_card_ptr
 187   // must never return false. Must only be called during GC.
 188   bool apply_closure_during_gc(G1CardTableEntryClosure* cl, uint worker_i);
 189 
 190   // If a full collection is happening, reset partial logs, and release
 191   // completed ones: the full collection will make them all irrelevant.
 192   void abandon_logs();
 193 
 194   // If any threads have partial logs, add them to the global list of logs.
 195   void concatenate_logs();
 196 
 197   void set_max_completed_buffers(size_t m) {
 198     _max_completed_buffers = m;
 199   }
 200   size_t max_completed_buffers() const {
 201     return _max_completed_buffers;
 202   }
 203 
 204   void set_completed_buffers_padding(size_t padding) {
 205     _completed_buffers_padding = padding;
 206   }
 207   size_t completed_buffers_padding() const {
 208     return _completed_buffers_padding;
 209   }
 210 
 211   jint processed_buffers_mut() {
 212     return _processed_buffers_mut;
 213   }
 214   jint processed_buffers_rs_thread() {
 215     return _processed_buffers_rs_thread;
 216   }
 217 
 218 };
 219 
 220 inline G1DirtyCardQueueSet* G1DirtyCardQueue::dirty_card_qset() const {
 221   return static_cast<G1DirtyCardQueueSet*>(qset());
 222 }
 223 
 224 #endif // SHARE_GC_G1_G1DIRTYCARDQUEUE_HPP