1 /* 2 * Copyright (c) 2001, 2017, 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_VM_GC_G1_G1CONCURRENTREFINE_HPP 26 #define SHARE_VM_GC_G1_G1CONCURRENTREFINE_HPP 27 28 #include "memory/allocation.hpp" 29 #include "utilities/globalDefinitions.hpp" 30 31 // Forward decl 32 class CardTableEntryClosure; 33 class G1ConcurrentRefine; 34 class G1ConcurrentRefineThread; 35 class outputStream; 36 class ThreadClosure; 37 38 // Helper class for refinement thread management. Used to start, stop and 39 // iterate over them. 40 class G1ConcurrentRefineThreadControl VALUE_OBJ_CLASS_SPEC { 41 G1ConcurrentRefine* _cr; 42 43 G1ConcurrentRefineThread** _threads; 44 uint _num_max_threads; 45 46 // Create the refinement thread for the given worker id. 47 // If initializing is true, ignore InjectGCWorkerCreationFailure. 48 G1ConcurrentRefineThread* create_refinement_thread(uint worker_id, bool initializing); 49 public: 50 G1ConcurrentRefineThreadControl(); 51 ~G1ConcurrentRefineThreadControl(); 52 53 jint initialize(G1ConcurrentRefine* cr, uint num_max_threads); 54 55 // If there is a "successor" thread that can be activated given the current id, 56 // activate it. 57 void maybe_activate_next(uint cur_worker_id); 58 59 void print_on(outputStream* st) const; 60 void worker_threads_do(ThreadClosure* tc); 61 void stop(); 62 }; 63 64 // Controls refinement threads and their activation based on the number of completed 65 // buffers currently available in the global dirty card queue. 66 // Refinement threads pick work from the queue based on these thresholds. They are activated 67 // gradually based on the amount of work to do. 68 // Refinement thread n activates thread n+1 if the instance of this class determines there 69 // is enough work available. Threads deactivate themselves if the current amount of 70 // completed buffers falls below their individual threshold. 71 class G1ConcurrentRefine : public CHeapObj<mtGC> { 72 G1ConcurrentRefineThreadControl _thread_control; 73 /* 74 * The value of the completed dirty card queue length falls into one of 3 zones: 75 * green, yellow, red. If the value is in [0, green) nothing is 76 * done, the buffers are left unprocessed to enable the caching effect of the 77 * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement 78 * threads are gradually activated. In [yellow, red) all threads are 79 * running. If the length becomes red (max queue length) the mutators start 80 * processing the buffers. 81 * 82 * There are some interesting cases (when G1UseAdaptiveConcRefinement 83 * is turned off): 84 * 1) green = yellow = red = 0. In this case the mutator will process all 85 * buffers. Except for those that are created by the deferred updates 86 * machinery during a collection. 87 * 2) green = 0. Means no caching. Can be a good way to minimize the 88 * amount of time spent updating remembered sets during a collection. 89 */ 90 size_t _green_zone; 91 size_t _yellow_zone; 92 size_t _red_zone; 93 size_t _min_yellow_zone_size; 94 95 G1ConcurrentRefine(size_t green_zone, 96 size_t yellow_zone, 97 size_t red_zone, 98 size_t min_yellow_zone_size); 99 100 // Update green/yellow/red zone values based on how well goals are being met. 101 void update_zones(double update_rs_time, 102 size_t update_rs_processed_buffers, 103 double goal_ms); 104 105 static uint worker_id_offset(); 106 void maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers); 107 108 jint initialize(); 109 public: 110 ~G1ConcurrentRefine(); 111 112 // Returns a G1ConcurrentRefine instance if succeeded to create/initialize the 113 // G1ConcurrentRefine instance. Otherwise, returns NULL with error code. 114 static G1ConcurrentRefine* create(jint* ecode); 115 116 void stop(); 117 118 // Adjust refinement thresholds based on work done during the pause and the goal time. 119 void adjust(double update_rs_time, size_t update_rs_processed_buffers, double goal_ms); 120 121 size_t activation_threshold(uint worker_id) const; 122 size_t deactivation_threshold(uint worker_id) const; 123 // Perform a single refinement step. Called by the refinement threads when woken up. 124 bool do_refinement_step(uint worker_id); 125 126 // Iterate over all concurrent refinement threads applying the given closure. 127 void threads_do(ThreadClosure *tc); 128 129 // Maximum number of refinement threads. 130 static uint max_num_threads(); 131 132 void print_threads_on(outputStream* st) const; 133 134 size_t green_zone() const { return _green_zone; } 135 size_t yellow_zone() const { return _yellow_zone; } 136 size_t red_zone() const { return _red_zone; } 137 }; 138 139 #endif // SHARE_VM_GC_G1_G1CONCURRENTREFINE_HPP