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