1 /* 2 * Copyright (c) 2016, 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_G1COLLECTIONSET_HPP 26 #define SHARE_VM_GC_G1_G1COLLECTIONSET_HPP 27 28 #include "gc/g1/collectionSetChooser.hpp" 29 #include "memory/allocation.hpp" 30 #include "utilities/debug.hpp" 31 #include "utilities/globalDefinitions.hpp" 32 33 class G1CollectedHeap; 34 class G1CollectorState; 35 class G1GCPhaseTimes; 36 class G1Policy; 37 class G1SurvivorRegions; 38 class HeapRegion; 39 40 class G1CollectionSet VALUE_OBJ_CLASS_SPEC { 41 G1CollectedHeap* _g1; 42 G1Policy* _policy; 43 44 CollectionSetChooser* _cset_chooser; 45 46 uint _eden_region_length; 47 uint _survivor_region_length; 48 uint _old_region_length; 49 50 // The head of the list (via "next_in_collection_set()") representing the 51 // current collection set. Set from the incrementally built collection 52 // set at the start of the pause. 53 HeapRegion* _head; 54 55 // The number of bytes in the collection set before the pause. Set from 56 // the incrementally built collection set at the start of an evacuation 57 // pause, and incremented in finalize_old_part() when adding old regions 58 // (if any) to the collection set. 59 size_t _bytes_used_before; 60 61 size_t _recorded_rs_lengths; 62 63 // The associated information that is maintained while the incremental 64 // collection set is being built with young regions. Used to populate 65 // the recorded info for the evacuation pause. 66 67 enum CSetBuildType { 68 Active, // We are actively building the collection set 69 Inactive // We are not actively building the collection set 70 }; 71 72 CSetBuildType _inc_build_state; 73 74 // The head of the incrementally built collection set. 75 HeapRegion* _inc_head; 76 77 // The tail of the incrementally built collection set. 78 HeapRegion* _inc_tail; 79 80 // The number of bytes in the incrementally built collection set. 81 // Used to set _collection_set_bytes_used_before at the start of 82 // an evacuation pause. 83 size_t _inc_bytes_used_before; 84 85 // The RSet lengths recorded for regions in the CSet. It is updated 86 // by the thread that adds a new region to the CSet. We assume that 87 // only one thread can be allocating a new CSet region (currently, 88 // it does so after taking the Heap_lock) hence no need to 89 // synchronize updates to this field. 90 size_t _inc_recorded_rs_lengths; 91 92 // A concurrent refinement thread periodically samples the young 93 // region RSets and needs to update _inc_recorded_rs_lengths as 94 // the RSets grow. Instead of having to synchronize updates to that 95 // field we accumulate them in this field and add it to 96 // _inc_recorded_rs_lengths_diffs at the start of a GC. 97 ssize_t _inc_recorded_rs_lengths_diffs; 98 99 // The predicted elapsed time it will take to collect the regions in 100 // the CSet. This is updated by the thread that adds a new region to 101 // the CSet. See the comment for _inc_recorded_rs_lengths about 102 // MT-safety assumptions. 103 double _inc_predicted_elapsed_time_ms; 104 105 // See the comment for _inc_recorded_rs_lengths_diffs. 106 double _inc_predicted_elapsed_time_ms_diffs; 107 108 uint _inc_region_length; 109 110 G1CollectorState* collector_state(); 111 G1GCPhaseTimes* phase_times(); 112 113 double predict_region_elapsed_time_ms(HeapRegion* hr); 114 115 void verify_young_cset_indices() const NOT_DEBUG_RETURN; 116 public: 117 G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy); 118 ~G1CollectionSet(); 119 120 CollectionSetChooser* cset_chooser(); 121 122 void init_region_lengths(uint eden_cset_region_length, 123 uint survivor_cset_region_length); 124 125 void set_recorded_rs_lengths(size_t rs_lengths); 126 127 uint region_length() const { return young_region_length() + 128 old_region_length(); } 129 uint young_region_length() const { return eden_region_length() + 130 survivor_region_length(); } 131 132 uint eden_region_length() const { return _eden_region_length; } 133 uint survivor_region_length() const { return _survivor_region_length; } 134 uint old_region_length() const { return _old_region_length; } 135 136 // Incremental CSet Support 137 138 // The head of the incrementally built collection set. 139 HeapRegion* inc_head() { return _inc_head; } 140 141 // The tail of the incrementally built collection set. 142 HeapRegion* inc_tail() { return _inc_tail; } 143 144 // Initialize incremental collection set info. 145 void start_incremental_building(); 146 147 // Perform any final calculations on the incremental CSet fields 148 // before we can use them. 149 void finalize_incremental_building(); 150 151 void clear_incremental() { 152 _inc_head = NULL; 153 _inc_tail = NULL; 154 _inc_region_length = 0; 155 } 156 157 // Stop adding regions to the incremental collection set 158 void stop_incremental_building() { _inc_build_state = Inactive; } 159 160 // The head of the list (via "next_in_collection_set()") representing the 161 // current collection set. 162 HeapRegion* head() { return _head; } 163 164 void clear_head() { _head = NULL; } 165 166 size_t recorded_rs_lengths() { return _recorded_rs_lengths; } 167 168 size_t bytes_used_before() const { 169 return _bytes_used_before; 170 } 171 172 void reset_bytes_used_before() { 173 _bytes_used_before = 0; 174 } 175 176 // Choose a new collection set. Marks the chosen regions as being 177 // "in_collection_set", and links them together. The head and number of 178 // the collection set are available via access methods. 179 double finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors); 180 void finalize_old_part(double time_remaining_ms); 181 182 // Add old region "hr" to the CSet. 183 void add_old_region(HeapRegion* hr); 184 185 // Update information about hr in the aggregated information for 186 // the incrementally built collection set. 187 void update_young_region_prediction(HeapRegion* hr, size_t new_rs_length); 188 189 // Add hr to the LHS of the incremental collection set. 190 void add_eden_region(HeapRegion* hr); 191 192 // Add hr to the RHS of the incremental collection set. 193 void add_survivor_regions(HeapRegion* hr); 194 195 #ifndef PRODUCT 196 void print(HeapRegion* list_head, outputStream* st); 197 #endif // !PRODUCT 198 199 private: 200 // Update the incremental cset information when adding a region 201 // (should not be called directly). 202 void add_young_region_common(HeapRegion* hr); 203 204 }; 205 206 #endif // SHARE_VM_GC_G1_G1COLLECTIONSET_HPP 207