1 /* 2 * Copyright (c) 2001, 2019, 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/heapRegion.hpp" 27 #include "gc/g1/heapRegionBounds.inline.hpp" 28 #include "gc/g1/heapRegionRemSet.hpp" 29 #include "gc/g1/sparsePRT.hpp" 30 #include "gc/shared/cardTableBarrierSet.hpp" 31 #include "gc/shared/space.inline.hpp" 32 #include "memory/allocation.inline.hpp" 33 #include "runtime/atomic.hpp" 34 #include "runtime/mutexLocker.hpp" 35 36 // Check that the size of the SparsePRTEntry is evenly divisible by the maximum 37 // member type to avoid SIGBUS when accessing them. 38 STATIC_ASSERT(sizeof(SparsePRTEntry) % sizeof(int) == 0); 39 40 void SparsePRTEntry::init(RegionIdx_t region_ind) { 41 // Check that the card array element type can represent all cards in the region. 42 // Choose a large SparsePRTEntry::card_elem_t (e.g. CardIdx_t) if required. 43 assert(((size_t)1 << (sizeof(SparsePRTEntry::card_elem_t) * BitsPerByte)) * 44 G1CardTable::card_size >= HeapRegionBounds::max_size(), "precondition"); 45 assert(G1RSetSparseRegionEntries > 0, "precondition"); 46 _region_ind = region_ind; 47 _next_index = RSHashTable::NullEntry; 48 _next_null = 0; 49 } 50 51 bool SparsePRTEntry::contains_card(CardIdx_t card_index) const { 52 for (int i = 0; i < num_valid_cards(); i++) { 53 if (card(i) == card_index) { 54 return true; 55 } 56 } 57 return false; 58 } 59 60 SparsePRTEntry::AddCardResult SparsePRTEntry::add_card(CardIdx_t card_index) { 61 for (int i = 0; i < num_valid_cards(); i++) { 62 if (card(i) == card_index) { 63 return found; 64 } 65 } 66 if (num_valid_cards() < cards_num() - 1) { 67 _cards[_next_null] = (card_elem_t)card_index; 68 _next_null++; 69 return added; 70 } 71 // Otherwise, we're full. 72 return overflow; 73 } 74 75 void SparsePRTEntry::copy_cards(card_elem_t* cards) const { 76 memcpy(cards, _cards, cards_num() * sizeof(card_elem_t)); 77 } 78 79 void SparsePRTEntry::copy_cards(SparsePRTEntry* e) const { 80 copy_cards(e->_cards); 81 assert(_next_null >= 0, "invariant"); 82 assert(_next_null <= cards_num(), "invariant"); 83 e->_next_null = _next_null; 84 } 85 86 // ---------------------------------------------------------------------- 87 88 float RSHashTable::TableOccupancyFactor = 0.5f; 89 90 RSHashTable::RSHashTable(size_t capacity) : 91 _num_entries(0), 92 _capacity(capacity), 93 _capacity_mask(capacity-1), 94 _occupied_entries(0), 95 _occupied_cards(0), 96 _entries(NULL), 97 _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)), 98 _free_region(0), 99 _free_list(NullEntry) 100 { 101 _num_entries = (capacity * TableOccupancyFactor) + 1; 102 _entries = (SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, _num_entries * SparsePRTEntry::size(), mtGC); 103 clear(); 104 } 105 106 RSHashTable::~RSHashTable() { 107 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries); 108 FREE_C_HEAP_ARRAY(int, _buckets); 109 } 110 111 void RSHashTable::clear() { 112 _occupied_entries = 0; 113 _occupied_cards = 0; 114 guarantee(_entries != NULL, "INV"); 115 guarantee(_buckets != NULL, "INV"); 116 117 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1, 118 "_capacity too large"); 119 120 // This will put -1 == NullEntry in the key field of all entries. 121 memset((void*)_entries, NullEntry, _num_entries * SparsePRTEntry::size()); 122 memset((void*)_buckets, NullEntry, _capacity * sizeof(int)); 123 _free_list = NullEntry; 124 _free_region = 0; 125 } 126 127 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) { 128 SparsePRTEntry* e = entry_for_region_ind_create(region_ind); 129 assert(e != NULL && e->r_ind() == region_ind, 130 "Postcondition of call above."); 131 SparsePRTEntry::AddCardResult res = e->add_card(card_index); 132 if (res == SparsePRTEntry::added) _occupied_cards++; 133 assert(e->num_valid_cards() > 0, "Postcondition"); 134 return res != SparsePRTEntry::overflow; 135 } 136 137 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const { 138 int ind = (int) (region_ind & capacity_mask()); 139 int cur_ind = _buckets[ind]; 140 SparsePRTEntry* cur; 141 while (cur_ind != NullEntry && 142 (cur = entry(cur_ind))->r_ind() != region_ind) { 143 cur_ind = cur->next_index(); 144 } 145 146 if (cur_ind == NullEntry) return NULL; 147 // Otherwise... 148 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above."); 149 assert(cur->num_valid_cards() > 0, "Inv"); 150 return cur; 151 } 152 153 bool RSHashTable::delete_entry(RegionIdx_t region_ind) { 154 int ind = (int) (region_ind & capacity_mask()); 155 int* prev_loc = &_buckets[ind]; 156 int cur_ind = *prev_loc; 157 SparsePRTEntry* cur; 158 while (cur_ind != NullEntry && 159 (cur = entry(cur_ind))->r_ind() != region_ind) { 160 prev_loc = cur->next_index_addr(); 161 cur_ind = *prev_loc; 162 } 163 164 if (cur_ind == NullEntry) return false; 165 // Otherwise, splice out "cur". 166 *prev_loc = cur->next_index(); 167 _occupied_cards -= cur->num_valid_cards(); 168 free_entry(cur_ind); 169 _occupied_entries--; 170 return true; 171 } 172 173 SparsePRTEntry* 174 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) { 175 SparsePRTEntry* res = get_entry(region_ind); 176 if (res == NULL) { 177 int new_ind = alloc_entry(); 178 res = entry(new_ind); 179 res->init(region_ind); 180 // Insert at front. 181 int ind = (int) (region_ind & capacity_mask()); 182 res->set_next_index(_buckets[ind]); 183 _buckets[ind] = new_ind; 184 _occupied_entries++; 185 } 186 return res; 187 } 188 189 int RSHashTable::alloc_entry() { 190 int res; 191 if (_free_list != NullEntry) { 192 res = _free_list; 193 _free_list = entry(res)->next_index(); 194 return res; 195 } else if ((size_t)_free_region < _num_entries) { 196 res = _free_region; 197 _free_region++; 198 return res; 199 } else { 200 return NullEntry; 201 } 202 } 203 204 void RSHashTable::free_entry(int fi) { 205 entry(fi)->set_next_index(_free_list); 206 _free_list = fi; 207 } 208 209 void RSHashTable::add_entry(SparsePRTEntry* e) { 210 assert(e->num_valid_cards() > 0, "Precondition."); 211 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind()); 212 e->copy_cards(e2); 213 _occupied_cards += e2->num_valid_cards(); 214 assert(e2->num_valid_cards() > 0, "Postcondition."); 215 } 216 217 CardIdx_t RSHashTableIter::find_first_card_in_list() { 218 while (_bl_ind != RSHashTable::NullEntry) { 219 SparsePRTEntry* sparse_entry = _rsht->entry(_bl_ind); 220 if (sparse_entry->num_valid_cards() > 0) { 221 return sparse_entry->card(0); 222 } else { 223 _bl_ind = sparse_entry->next_index(); 224 } 225 } 226 // Otherwise, none found: 227 return NoCardFound; 228 } 229 230 size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) { 231 return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci; 232 } 233 234 bool RSHashTableIter::has_next(size_t& card_index) { 235 _card_ind++; 236 if (_bl_ind >= 0) { 237 SparsePRTEntry* e = _rsht->entry(_bl_ind); 238 if (_card_ind < e->num_valid_cards()) { 239 CardIdx_t ci = e->card(_card_ind); 240 card_index = compute_card_ind(ci); 241 return true; 242 } 243 } 244 245 // Otherwise, must find the next valid entry. 246 _card_ind = 0; 247 248 if (_bl_ind != RSHashTable::NullEntry) { 249 _bl_ind = _rsht->entry(_bl_ind)->next_index(); 250 CardIdx_t ci = find_first_card_in_list(); 251 if (ci != NoCardFound) { 252 card_index = compute_card_ind(ci); 253 return true; 254 } 255 } 256 // If we didn't return above, must go to the next non-null table index. 257 _tbl_ind++; 258 while ((size_t)_tbl_ind < _rsht->capacity()) { 259 _bl_ind = _rsht->_buckets[_tbl_ind]; 260 CardIdx_t ci = find_first_card_in_list(); 261 if (ci != NoCardFound) { 262 card_index = compute_card_ind(ci); 263 return true; 264 } 265 // Otherwise, try next entry. 266 _tbl_ind++; 267 } 268 // Otherwise, there were no entry. 269 return false; 270 } 271 272 bool RSHashTableBucketIter::has_next(SparsePRTEntry*& entry) { 273 while (_bl_ind == RSHashTable::NullEntry) { 274 if (_tbl_ind == (int)_rsht->capacity() - 1) { 275 return false; 276 } 277 _tbl_ind++; 278 _bl_ind = _rsht->_buckets[_tbl_ind]; 279 } 280 entry = _rsht->entry(_bl_ind); 281 _bl_ind = entry->next_index(); 282 return true; 283 } 284 285 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const { 286 SparsePRTEntry* e = get_entry(region_index); 287 return (e != NULL && e->contains_card(card_index)); 288 } 289 290 size_t RSHashTable::mem_size() const { 291 return sizeof(RSHashTable) + 292 _num_entries * (SparsePRTEntry::size() + sizeof(int)); 293 } 294 295 // ---------------------------------------------------------------------- 296 297 SparsePRT::SparsePRT() : 298 _table(new RSHashTable(InitialCapacity)) { 299 } 300 301 302 SparsePRT::~SparsePRT() { 303 delete _table; 304 } 305 306 307 size_t SparsePRT::mem_size() const { 308 // We ignore "_cur" here, because it either = _next, or else it is 309 // on the deleted list. 310 return sizeof(SparsePRT) + _table->mem_size(); 311 } 312 313 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) { 314 if (_table->should_expand()) { 315 expand(); 316 } 317 return _table->add_card(region_id, card_index); 318 } 319 320 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) { 321 return _table->get_entry(region_id); 322 } 323 324 bool SparsePRT::delete_entry(RegionIdx_t region_id) { 325 return _table->delete_entry(region_id); 326 } 327 328 void SparsePRT::clear() { 329 // If the entry table is not at initial capacity, just create a new one. 330 if (_table->capacity() != InitialCapacity) { 331 delete _table; 332 _table = new RSHashTable(InitialCapacity); 333 } else { 334 _table->clear(); 335 } 336 } 337 338 void SparsePRT::expand() { 339 RSHashTable* last = _table; 340 _table = new RSHashTable(last->capacity() * 2); 341 for (size_t i = 0; i < last->num_entries(); i++) { 342 SparsePRTEntry* e = last->entry((int)i); 343 if (e->valid_entry()) { 344 _table->add_entry(e); 345 } 346 } 347 delete last; 348 }