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_G1CONCURRENTREFINE_HPP 26 #define SHARE_GC_G1_G1CONCURRENTREFINE_HPP 27 28 #include "memory/allocation.hpp" 29 #include "gc/g1/g1EpochSynchronizer.hpp" 30 #include "utilities/globalDefinitions.hpp" 31 #include "utilities/ticks.hpp" 32 33 // Forward decl 34 class G1ConcurrentRefine; 35 class G1ConcurrentRefineThread; 36 class outputStream; 37 class ThreadClosure; 38 39 // Helper class for refinement thread management. Used to start, stop and 40 // iterate over them. 41 class G1ConcurrentRefineThreadControl { 42 G1ConcurrentRefine* _cr; 43 44 G1ConcurrentRefineThread** _threads; 45 uint _num_max_threads; 46 47 // Create the refinement thread for the given worker id. 48 // If initializing is true, ignore InjectGCWorkerCreationFailure. 49 G1ConcurrentRefineThread* create_refinement_thread(uint worker_id, bool initializing); 50 public: 51 G1ConcurrentRefineThreadControl(); 52 ~G1ConcurrentRefineThreadControl(); 53 54 jint initialize(G1ConcurrentRefine* cr, uint num_max_threads); 55 56 // If there is a "successor" thread that can be activated given the current id, 57 // activate it. 58 void maybe_activate_next(uint cur_worker_id); 59 60 void print_on(outputStream* st) const; 61 void worker_threads_do(ThreadClosure* tc); 62 void stop(); 63 }; 64 65 // Controls refinement threads and their activation based on the number of 66 // cards currently available in the global dirty card queue. 67 // Refinement threads obtain work from the queue (a buffer at a time) based 68 // on these thresholds. They are activated gradually based on the amount of 69 // work to do. 70 // Refinement thread n activates thread n+1 if the instance of this class determines there 71 // is enough work available. Threads deactivate themselves if the current amount of 72 // available cards falls below their individual threshold. 73 class G1ConcurrentRefine : public CHeapObj<mtGC> { 74 G1ConcurrentRefineThreadControl _thread_control; 75 G1EpochSynchronizerCounters _synchronizer_counters; 76 /* 77 * The value of the completed dirty card queue length falls into one of 3 zones: 78 * green, yellow, red. If the value is in [0, green) nothing is 79 * done, the buffered cards are left unprocessed to enable the caching effect of the 80 * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement 81 * threads are gradually activated. In [yellow, red) all threads are 82 * running. If the length becomes red (max queue length) the mutators start 83 * processing cards too. 84 * 85 * There are some interesting cases (when G1UseAdaptiveConcRefinement 86 * is turned off): 87 * 1) green = yellow = red = 0. In this case the mutator will process all 88 * cards. Except for those that are created by the deferred updates 89 * machinery during a collection. 90 * 2) green = 0. Means no caching. Can be a good way to minimize the 91 * amount of time spent updating remembered sets during a collection. 92 */ 93 size_t _green_zone; 94 size_t _yellow_zone; 95 size_t _red_zone; 96 size_t _min_yellow_zone_size; 97 98 G1ConcurrentRefine(size_t green_zone, 99 size_t yellow_zone, 100 size_t red_zone, 101 size_t min_yellow_zone_size); 102 103 // Update green/yellow/red zone values based on how well goals are being met. 104 void update_zones(double logged_cards_scan_time, 105 size_t processed_logged_cards, 106 double goal_ms); 107 108 static uint worker_id_offset(); 109 void maybe_activate_more_threads(uint worker_id, size_t num_cur_cards); 110 111 jint initialize(); 112 public: 113 ~G1ConcurrentRefine(); 114 115 // Returns a G1ConcurrentRefine instance if succeeded to create/initialize the 116 // G1ConcurrentRefine instance. Otherwise, returns NULL with error code. 117 static G1ConcurrentRefine* create(jint* ecode); 118 119 void stop(); 120 121 // Adjust refinement thresholds based on work done during the pause and the goal time. 122 void adjust(double logged_cards_scan_time, size_t processed_logged_cards, double goal_ms); 123 124 struct RefinementStats { 125 Tickspan _time; 126 size_t _cards; 127 RefinementStats(Tickspan time, size_t cards) : _time(time), _cards(cards) {} 128 }; 129 130 RefinementStats total_refinement_stats() const; 131 132 // Cards in the dirty card queue set. 133 size_t activation_threshold(uint worker_id) const; 134 size_t deactivation_threshold(uint worker_id) const; 135 136 // Perform a single refinement step; called by the refinement 137 // threads. Returns true if there was refinement work available. 138 // Increments *total_refined_cards. 139 bool do_refinement_step(uint worker_id, size_t* total_refined_cards); 140 141 // Iterate over all concurrent refinement threads applying the given closure. 142 void threads_do(ThreadClosure *tc); 143 144 // Maximum number of refinement threads. 145 static uint max_num_threads(); 146 147 void print_threads_on(outputStream* st) const; 148 149 G1EpochSynchronizerCounters* synchronizer_counters() { 150 return &_synchronizer_counters; 151 } 152 153 // Cards in the dirty card queue set. 154 size_t green_zone() const { return _green_zone; } 155 size_t yellow_zone() const { return _yellow_zone; } 156 size_t red_zone() const { return _red_zone; } 157 }; 158 159 #endif // SHARE_GC_G1_G1CONCURRENTREFINE_HPP