1 /* 2 * Copyright (c) 2015, 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 #include "precompiled.hpp" 26 #include "gc/g1/g1CollectedHeap.hpp" 27 #include "gc/g1/g1CollectorPolicy.hpp" 28 #include "gc/g1/heapRegion.hpp" 29 #include "gc/g1/heapRegion.inline.hpp" 30 #include "gc/g1/heapRegionRemSet.hpp" 31 #include "gc/g1/youngList.hpp" 32 #include "utilities/ostream.hpp" 33 34 YoungList::YoungList(G1CollectedHeap* g1h) : 35 _g1h(g1h), _head(NULL), _length(0), _last_sampled_rs_lengths(0), 36 _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0) { 37 guarantee(check_list_empty(false), "just making sure..."); 38 } 39 40 void YoungList::push_region(HeapRegion *hr) { 41 assert(!hr->is_young(), "should not already be young"); 42 assert(hr->get_next_young_region() == NULL, "cause it should!"); 43 44 hr->set_next_young_region(_head); 45 _head = hr; 46 47 _g1h->g1_policy()->set_region_eden(hr, (int) _length); 48 ++_length; 49 } 50 51 void YoungList::add_survivor_region(HeapRegion* hr) { 52 assert(hr->is_survivor(), "should be flagged as survivor region"); 53 assert(hr->get_next_young_region() == NULL, "cause it should!"); 54 55 hr->set_next_young_region(_survivor_head); 56 if (_survivor_head == NULL) { 57 _survivor_tail = hr; 58 } 59 _survivor_head = hr; 60 ++_survivor_length; 61 } 62 63 void YoungList::empty_list(HeapRegion* list) { 64 while (list != NULL) { 65 HeapRegion* next = list->get_next_young_region(); 66 list->set_next_young_region(NULL); 67 list->uninstall_surv_rate_group(); 68 // This is called before a Full GC and all the non-empty / 69 // non-humongous regions at the end of the Full GC will end up as 70 // old anyway. 71 list->set_old(); 72 list = next; 73 } 74 } 75 76 void YoungList::empty_list() { 77 assert(check_list_well_formed(), "young list should be well formed"); 78 79 empty_list(_head); 80 _head = NULL; 81 _length = 0; 82 83 empty_list(_survivor_head); 84 _survivor_head = NULL; 85 _survivor_tail = NULL; 86 _survivor_length = 0; 87 88 _last_sampled_rs_lengths = 0; 89 90 assert(check_list_empty(false), "just making sure..."); 91 } 92 93 bool YoungList::check_list_well_formed() { 94 bool ret = true; 95 96 uint length = 0; 97 HeapRegion* curr = _head; 98 HeapRegion* last = NULL; 99 while (curr != NULL) { 100 if (!curr->is_young()) { 101 gclog_or_tty->print_cr("### YOUNG REGION " PTR_FORMAT "-" PTR_FORMAT " " 102 "incorrectly tagged (y: %d, surv: %d)", 103 p2i(curr->bottom()), p2i(curr->end()), 104 curr->is_young(), curr->is_survivor()); 105 ret = false; 106 } 107 ++length; 108 last = curr; 109 curr = curr->get_next_young_region(); 110 } 111 ret = ret && (length == _length); 112 113 if (!ret) { 114 gclog_or_tty->print_cr("### YOUNG LIST seems not well formed!"); 115 gclog_or_tty->print_cr("### list has %u entries, _length is %u", 116 length, _length); 117 } 118 119 return ret; 120 } 121 122 bool YoungList::check_list_empty(bool check_sample) { 123 bool ret = true; 124 125 if (_length != 0) { 126 gclog_or_tty->print_cr("### YOUNG LIST should have 0 length, not %u", 127 _length); 128 ret = false; 129 } 130 if (check_sample && _last_sampled_rs_lengths != 0) { 131 gclog_or_tty->print_cr("### YOUNG LIST has non-zero last sampled RS lengths"); 132 ret = false; 133 } 134 if (_head != NULL) { 135 gclog_or_tty->print_cr("### YOUNG LIST does not have a NULL head"); 136 ret = false; 137 } 138 if (!ret) { 139 gclog_or_tty->print_cr("### YOUNG LIST does not seem empty"); 140 } 141 142 return ret; 143 } 144 145 void 146 YoungList::rs_length_sampling_init() { 147 _sampled_rs_lengths = 0; 148 _curr = _head; 149 } 150 151 bool 152 YoungList::rs_length_sampling_more() { 153 return _curr != NULL; 154 } 155 156 void 157 YoungList::rs_length_sampling_next() { 158 assert( _curr != NULL, "invariant" ); 159 size_t rs_length = _curr->rem_set()->occupied(); 160 161 _sampled_rs_lengths += rs_length; 162 163 // The current region may not yet have been added to the 164 // incremental collection set (it gets added when it is 165 // retired as the current allocation region). 166 if (_curr->in_collection_set()) { 167 // Update the collection set policy information for this region 168 _g1h->g1_policy()->update_incremental_cset_info(_curr, rs_length); 169 } 170 171 _curr = _curr->get_next_young_region(); 172 if (_curr == NULL) { 173 _last_sampled_rs_lengths = _sampled_rs_lengths; 174 // gclog_or_tty->print_cr("last sampled RS lengths = %d", _last_sampled_rs_lengths); 175 } 176 } 177 178 void 179 YoungList::reset_auxilary_lists() { 180 guarantee( is_empty(), "young list should be empty" ); 181 assert(check_list_well_formed(), "young list should be well formed"); 182 183 // Add survivor regions to SurvRateGroup. 184 _g1h->g1_policy()->note_start_adding_survivor_regions(); 185 _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */); 186 187 int young_index_in_cset = 0; 188 for (HeapRegion* curr = _survivor_head; 189 curr != NULL; 190 curr = curr->get_next_young_region()) { 191 _g1h->g1_policy()->set_region_survivor(curr, young_index_in_cset); 192 193 // The region is a non-empty survivor so let's add it to 194 // the incremental collection set for the next evacuation 195 // pause. 196 _g1h->g1_policy()->add_region_to_incremental_cset_rhs(curr); 197 young_index_in_cset += 1; 198 } 199 assert((uint) young_index_in_cset == _survivor_length, "post-condition"); 200 _g1h->g1_policy()->note_stop_adding_survivor_regions(); 201 202 _head = _survivor_head; 203 _length = _survivor_length; 204 if (_survivor_head != NULL) { 205 assert(_survivor_tail != NULL, "cause it shouldn't be"); 206 assert(_survivor_length > 0, "invariant"); 207 _survivor_tail->set_next_young_region(NULL); 208 } 209 210 // Don't clear the survivor list handles until the start of 211 // the next evacuation pause - we need it in order to re-tag 212 // the survivor regions from this evacuation pause as 'young' 213 // at the start of the next. 214 215 _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */); 216 217 assert(check_list_well_formed(), "young list should be well formed"); 218 } 219 220 void YoungList::print() { 221 HeapRegion* lists[] = {_head, _survivor_head}; 222 const char* names[] = {"YOUNG", "SURVIVOR"}; 223 224 for (uint list = 0; list < ARRAY_SIZE(lists); ++list) { 225 gclog_or_tty->print_cr("%s LIST CONTENTS", names[list]); 226 HeapRegion *curr = lists[list]; 227 if (curr == NULL) { 228 gclog_or_tty->print_cr(" empty"); 229 } 230 while (curr != NULL) { 231 gclog_or_tty->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT ", N: " PTR_FORMAT ", age: %4d", 232 HR_FORMAT_PARAMS(curr), 233 p2i(curr->prev_top_at_mark_start()), 234 p2i(curr->next_top_at_mark_start()), 235 curr->age_in_surv_rate_group_cond()); 236 curr = curr->get_next_young_region(); 237 } 238 } 239 240 gclog_or_tty->cr(); 241 }