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* _cg1r; 42 43 G1ConcurrentRefineThread** _threads; 44 uint _num_max_threads; 45 public: 46 G1ConcurrentRefineThreadControl(); 47 ~G1ConcurrentRefineThreadControl(); 48 49 void initialize(G1ConcurrentRefine* cg1r, uint num_max_threads); 50 51 // If there is a "successor" thread that can be activated given the current id, 52 // activate it. 53 void maybe_activate_next(uint cur_worker_id); 54 55 void print_on(outputStream* st) const; 56 void worker_threads_do(ThreadClosure* tc); 57 void stop(); 58 }; 59 60 // Controls refinement threads and their activation based on the number of completed 61 // buffers currently available in the global dirty card queue. 62 // Refinement threads pick work from the queue based on these thresholds. They are activated 63 // gradually based on the amount of work to do. 64 // Refinement thread n activates thread n+1 if the instance of this class determines there 65 // is enough work available. Threads deactivate themselves if the current amount of 66 // completed buffers falls below their individual threshold. 67 class G1ConcurrentRefine : public CHeapObj<mtGC> { 68 G1ConcurrentRefineThreadControl _thread_control; 69 /* 70 * The value of the completed dirty card queue length falls into one of 3 zones: 71 * green, yellow, red. If the value is in [0, green) nothing is 72 * done, the buffers are left unprocessed to enable the caching effect of the 73 * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement 74 * threads are gradually activated. In [yellow, red) all threads are 75 * running. If the length becomes red (max queue length) the mutators start 76 * processing the buffers. 77 * 78 * There are some interesting cases (when G1UseAdaptiveConcRefinement 79 * is turned off): 80 * 1) green = yellow = red = 0. In this case the mutator will process all 81 * buffers. Except for those that are created by the deferred updates 82 * machinery during a collection. 83 * 2) green = 0. Means no caching. Can be a good way to minimize the 84 * amount of time spent updating remembered sets during a collection. 85 */ 86 size_t _green_zone; 87 size_t _yellow_zone; 88 size_t _red_zone; 89 size_t _min_yellow_zone_size; 90 91 G1ConcurrentRefine(size_t green_zone, 92 size_t yellow_zone, 93 size_t red_zone, 94 size_t min_yellow_zone_size); 95 96 // Update green/yellow/red zone values based on how well goals are being met. 97 void update_zones(double update_rs_time, 98 size_t update_rs_processed_buffers, 99 double goal_ms); 100 101 static uint worker_id_offset(); 102 void maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers); 103 104 public: 105 ~G1ConcurrentRefine(); 106 107 // Returns a G1ConcurrentRefine instance if succeeded to create/initialize the 108 // G1ConcurrentRefine instance. Otherwise, returns NULL with error code. 109 static G1ConcurrentRefine* create(jint* ecode); 110 111 void stop(); 112 113 // Adjust refinement thresholds based on work done during the pause and the goal time. 114 void adjust(double update_rs_time, size_t update_rs_processed_buffers, double goal_ms); 115 116 size_t activation_threshold(uint worker_id) const; 117 size_t deactivation_threshold(uint worker_id) const; 118 // Perform a single refinement step. Called by the refinement threads when woken up. 119 bool do_refinement_step(uint worker_id); 120 121 // Iterate over all concurrent refinement threads applying the given closure. 122 void threads_do(ThreadClosure *tc); 123 124 // Maximum number of refinement threads. 125 static uint max_num_threads(); 126 127 void print_threads_on(outputStream* st) const; 128 129 size_t green_zone() const { return _green_zone; } 130 size_t yellow_zone() const { return _yellow_zone; } 131 size_t red_zone() const { return _red_zone; } 132 }; 133 134 #endif // SHARE_VM_GC_G1_G1CONCURRENTREFINE_HPP