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 G1CollectorPolicy; 35 class G1CollectorState; 36 class G1GCPhaseTimes; 37 class HeapRegion; 38 39 class G1CollectionSet VALUE_OBJ_CLASS_SPEC { 40 G1CollectedHeap* _g1; 41 G1CollectorPolicy* _policy; 42 43 CollectionSetChooser* _cset_chooser; 44 45 uint _eden_region_length; 46 uint _survivor_region_length; 47 uint _old_region_length; 48 49 // The head of the list (via "next_in_collection_set()") representing the 50 // current collection set. Set from the incrementally built collection 51 // set at the start of the pause. 52 HeapRegion* _head; 53 54 // The number of bytes in the collection set before the pause. Set from 55 // the incrementally built collection set at the start of an evacuation 56 // pause, and incremented in finalize_old_part() when adding old regions 57 // (if any) to the collection set. 58 size_t _bytes_used_before; 59 60 // The sum of live bytes in the collection set, set as described above. 61 size_t _bytes_live_before; 62 63 size_t _recorded_rs_lengths; 64 65 // The associated information that is maintained while the incremental 66 // collection set is being built with young regions. Used to populate 67 // the recorded info for the evacuation pause. 68 69 enum CSetBuildType { 70 Active, // We are actively building the collection set 71 Inactive // We are not actively building the collection set 72 }; 73 74 CSetBuildType _inc_build_state; 75 76 // The head of the incrementally built collection set. 77 HeapRegion* _inc_head; 78 79 // The tail of the incrementally built collection set. 80 HeapRegion* _inc_tail; 81 82 // The number of bytes in the incrementally built collection set. 83 // Used to set _collection_set_bytes_used_before at the start of 84 // an evacuation pause. 85 size_t _inc_bytes_used_before; 86 87 // The number of live bytes in the incrementally built collection set. 88 size_t _inc_bytes_live_before; 89 90 // The RSet lengths recorded for regions in the CSet. It is updated 91 // by the thread that adds a new region to the CSet. We assume that 92 // only one thread can be allocating a new CSet region (currently, 93 // it does so after taking the Heap_lock) hence no need to 94 // synchronize updates to this field. 95 size_t _inc_recorded_rs_lengths; 96 97 // A concurrent refinement thread periodically samples the young 98 // region RSets and needs to update _inc_recorded_rs_lengths as 99 // the RSets grow. Instead of having to synchronize updates to that 100 // field we accumulate them in this field and add it to 101 // _inc_recorded_rs_lengths_diffs at the start of a GC. 102 ssize_t _inc_recorded_rs_lengths_diffs; 103 104 // The predicted elapsed time it will take to collect the regions in 105 // the CSet. This is updated by the thread that adds a new region to 106 // the CSet. See the comment for _inc_recorded_rs_lengths about 107 // MT-safety assumptions. 108 double _inc_predicted_elapsed_time_ms; 109 110 // See the comment for _inc_recorded_rs_lengths_diffs. 111 double _inc_predicted_elapsed_time_ms_diffs; 112 113 G1CollectorState* collector_state(); 114 G1GCPhaseTimes* phase_times(); 115 116 double predict_region_elapsed_time_ms(HeapRegion* hr); 117 118 public: 119 G1CollectionSet(G1CollectedHeap* g1h); 120 ~G1CollectionSet(); 121 122 void set_policy(G1CollectorPolicy* g1p) { 123 assert(_policy == NULL, "should only initialize once"); 124 _policy = g1p; 125 } 126 127 CollectionSetChooser* cset_chooser(); 128 129 void init_region_lengths(uint eden_cset_region_length, 130 uint survivor_cset_region_length); 131 132 void set_recorded_rs_lengths(size_t rs_lengths); 133 134 uint region_length() const { return young_region_length() + 135 old_region_length(); } 136 uint young_region_length() const { return eden_region_length() + 137 survivor_region_length(); } 138 139 uint eden_region_length() const { return _eden_region_length; } 140 uint survivor_region_length() const { return _survivor_region_length; } 141 uint old_region_length() const { return _old_region_length; } 142 143 // Incremental CSet Support 144 145 // The head of the incrementally built collection set. 146 HeapRegion* inc_head() { return _inc_head; } 147 148 // The tail of the incrementally built collection set. 149 HeapRegion* inc_tail() { return _inc_tail; } 150 151 // Initialize incremental collection set info. 152 void start_incremental_building(); 153 154 // Perform any final calculations on the incremental CSet fields 155 // before we can use them. 156 void finalize_incremental_building(); 157 158 void clear_incremental() { 159 _inc_head = NULL; 160 _inc_tail = NULL; 161 } 162 163 // Stop adding regions to the incremental collection set 164 void stop_incremental_building() { _inc_build_state = Inactive; } 165 166 // The head of the list (via "next_in_collection_set()") representing the 167 // current collection set. 168 HeapRegion* head() { return _head; } 169 170 void clear_head() { _head = NULL; } 171 172 size_t recorded_rs_lengths() { return _recorded_rs_lengths; } 173 174 size_t bytes_used_before() const { 175 return _bytes_used_before; 176 } 177 178 void reset_bytes_used_before() { 179 _bytes_used_before = 0; 180 } 181 182 void reset_bytes_live_before() { 183 _bytes_live_before = 0; 184 } 185 186 // Choose a new collection set. Marks the chosen regions as being 187 // "in_collection_set", and links them together. The head and number of 188 // the collection set are available via access methods. 189 double finalize_young_part(double target_pause_time_ms); 190 void finalize_old_part(double time_remaining_ms); 191 192 // Add old region "hr" to the CSet. 193 void add_old_region(HeapRegion* hr); 194 195 // Update information about hr in the aggregated information for 196 // the incrementally built collection set. 197 void update_young_region_prediction(HeapRegion* hr, size_t new_rs_length); 198 199 // Add hr to the LHS of the incremental collection set. 200 void add_eden_region(HeapRegion* hr); 201 202 // Add hr to the RHS of the incremental collection set. 203 void add_survivor_regions(HeapRegion* hr); 204 205 #ifndef PRODUCT 206 void print(HeapRegion* list_head, outputStream* st); 207 #endif // !PRODUCT 208 209 private: 210 // Update the incremental cset information when adding a region 211 // (should not be called directly). 212 void add_young_region_common(HeapRegion* hr); 213 214 }; 215 216 #endif // SHARE_VM_GC_G1_G1COLLECTIONSET_HPP 217