1 /* 2 * Copyright (c) 2001, 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 #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/cardTableModRefBS.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 _capacity(capacity), _capacity_mask(capacity-1), 92 _occupied_entries(0), _occupied_cards(0), 93 _entries(NULL), 94 _buckets(NEW_C_HEAP_ARRAY(int, capacity, mtGC)), 95 _free_list(NullEntry), _free_region(0) 96 { 97 _num_entries = (capacity * TableOccupancyFactor) + 1; 98 _entries = (SparsePRTEntry*)NEW_C_HEAP_ARRAY(char, _num_entries * SparsePRTEntry::size(), mtGC); 99 clear(); 100 } 101 102 RSHashTable::~RSHashTable() { 103 if (_entries != NULL) { 104 FREE_C_HEAP_ARRAY(SparsePRTEntry, _entries); 105 _entries = NULL; 106 } 107 if (_buckets != NULL) { 108 FREE_C_HEAP_ARRAY(int, _buckets); 109 _buckets = NULL; 110 } 111 } 112 113 void RSHashTable::clear() { 114 _occupied_entries = 0; 115 _occupied_cards = 0; 116 guarantee(_entries != NULL, "INV"); 117 guarantee(_buckets != NULL, "INV"); 118 119 guarantee(_capacity <= ((size_t)1 << (sizeof(int)*BitsPerByte-1)) - 1, 120 "_capacity too large"); 121 122 // This will put -1 == NullEntry in the key field of all entries. 123 memset(_entries, NullEntry, _num_entries * SparsePRTEntry::size()); 124 memset(_buckets, NullEntry, _capacity * sizeof(int)); 125 _free_list = NullEntry; 126 _free_region = 0; 127 } 128 129 bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) { 130 SparsePRTEntry* e = entry_for_region_ind_create(region_ind); 131 assert(e != NULL && e->r_ind() == region_ind, 132 "Postcondition of call above."); 133 SparsePRTEntry::AddCardResult res = e->add_card(card_index); 134 if (res == SparsePRTEntry::added) _occupied_cards++; 135 assert(e->num_valid_cards() > 0, "Postcondition"); 136 return res != SparsePRTEntry::overflow; 137 } 138 139 SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const { 140 int ind = (int) (region_ind & capacity_mask()); 141 int cur_ind = _buckets[ind]; 142 SparsePRTEntry* cur; 143 while (cur_ind != NullEntry && 144 (cur = entry(cur_ind))->r_ind() != region_ind) { 145 cur_ind = cur->next_index(); 146 } 147 148 if (cur_ind == NullEntry) return NULL; 149 // Otherwise... 150 assert(cur->r_ind() == region_ind, "Postcondition of loop + test above."); 151 assert(cur->num_valid_cards() > 0, "Inv"); 152 return cur; 153 } 154 155 bool RSHashTable::delete_entry(RegionIdx_t region_ind) { 156 int ind = (int) (region_ind & capacity_mask()); 157 int* prev_loc = &_buckets[ind]; 158 int cur_ind = *prev_loc; 159 SparsePRTEntry* cur; 160 while (cur_ind != NullEntry && 161 (cur = entry(cur_ind))->r_ind() != region_ind) { 162 prev_loc = cur->next_index_addr(); 163 cur_ind = *prev_loc; 164 } 165 166 if (cur_ind == NullEntry) return false; 167 // Otherwise, splice out "cur". 168 *prev_loc = cur->next_index(); 169 _occupied_cards -= cur->num_valid_cards(); 170 free_entry(cur_ind); 171 _occupied_entries--; 172 return true; 173 } 174 175 SparsePRTEntry* 176 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) { 177 SparsePRTEntry* res = get_entry(region_ind); 178 if (res == NULL) { 179 int new_ind = alloc_entry(); 180 res = entry(new_ind); 181 res->init(region_ind); 182 // Insert at front. 183 int ind = (int) (region_ind & capacity_mask()); 184 res->set_next_index(_buckets[ind]); 185 _buckets[ind] = new_ind; 186 _occupied_entries++; 187 } 188 return res; 189 } 190 191 int RSHashTable::alloc_entry() { 192 int res; 193 if (_free_list != NullEntry) { 194 res = _free_list; 195 _free_list = entry(res)->next_index(); 196 return res; 197 } else if ((size_t)_free_region < _num_entries) { 198 res = _free_region; 199 _free_region++; 200 return res; 201 } else { 202 return NullEntry; 203 } 204 } 205 206 void RSHashTable::free_entry(int fi) { 207 entry(fi)->set_next_index(_free_list); 208 _free_list = fi; 209 } 210 211 void RSHashTable::add_entry(SparsePRTEntry* e) { 212 assert(e->num_valid_cards() > 0, "Precondition."); 213 SparsePRTEntry* e2 = entry_for_region_ind_create(e->r_ind()); 214 e->copy_cards(e2); 215 _occupied_cards += e2->num_valid_cards(); 216 assert(e2->num_valid_cards() > 0, "Postcondition."); 217 } 218 219 CardIdx_t RSHashTableIter::find_first_card_in_list() { 220 while (_bl_ind != RSHashTable::NullEntry) { 221 SparsePRTEntry* sparse_entry = _rsht->entry(_bl_ind); 222 if (sparse_entry->num_valid_cards() > 0) { 223 return sparse_entry->card(0); 224 } else { 225 _bl_ind = sparse_entry->next_index(); 226 } 227 } 228 // Otherwise, none found: 229 return NoCardFound; 230 } 231 232 size_t RSHashTableIter::compute_card_ind(CardIdx_t ci) { 233 return (_rsht->entry(_bl_ind)->r_ind() * HeapRegion::CardsPerRegion) + ci; 234 } 235 236 bool RSHashTableIter::has_next(size_t& card_index) { 237 _card_ind++; 238 if (_bl_ind >= 0) { 239 SparsePRTEntry* e = _rsht->entry(_bl_ind); 240 if (_card_ind < e->num_valid_cards()) { 241 CardIdx_t ci = e->card(_card_ind); 242 card_index = compute_card_ind(ci); 243 return true; 244 } 245 } 246 247 // Otherwise, must find the next valid entry. 248 _card_ind = 0; 249 250 if (_bl_ind != RSHashTable::NullEntry) { 251 _bl_ind = _rsht->entry(_bl_ind)->next_index(); 252 CardIdx_t ci = find_first_card_in_list(); 253 if (ci != NoCardFound) { 254 card_index = compute_card_ind(ci); 255 return true; 256 } 257 } 258 // If we didn't return above, must go to the next non-null table index. 259 _tbl_ind++; 260 while ((size_t)_tbl_ind < _rsht->capacity()) { 261 _bl_ind = _rsht->_buckets[_tbl_ind]; 262 CardIdx_t ci = find_first_card_in_list(); 263 if (ci != NoCardFound) { 264 card_index = compute_card_ind(ci); 265 return true; 266 } 267 // Otherwise, try next entry. 268 _tbl_ind++; 269 } 270 // Otherwise, there were no entry. 271 return false; 272 } 273 274 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const { 275 SparsePRTEntry* e = get_entry(region_index); 276 return (e != NULL && e->contains_card(card_index)); 277 } 278 279 size_t RSHashTable::mem_size() const { 280 return sizeof(RSHashTable) + 281 _num_entries * (SparsePRTEntry::size() + sizeof(int)); 282 } 283 284 // ---------------------------------------------------------------------- 285 286 SparsePRT* volatile SparsePRT::_head_expanded_list = NULL; 287 288 void SparsePRT::add_to_expanded_list(SparsePRT* sprt) { 289 // We could expand multiple times in a pause -- only put on list once. 290 if (sprt->expanded()) return; 291 sprt->set_expanded(true); 292 SparsePRT* hd = _head_expanded_list; 293 while (true) { 294 sprt->_next_expanded = hd; 295 SparsePRT* res = 296 (SparsePRT*) 297 Atomic::cmpxchg_ptr(sprt, &_head_expanded_list, hd); 298 if (res == hd) return; 299 else hd = res; 300 } 301 } 302 303 304 SparsePRT* SparsePRT::get_from_expanded_list() { 305 SparsePRT* hd = _head_expanded_list; 306 while (hd != NULL) { 307 SparsePRT* next = hd->next_expanded(); 308 SparsePRT* res = 309 (SparsePRT*) 310 Atomic::cmpxchg_ptr(next, &_head_expanded_list, hd); 311 if (res == hd) { 312 hd->set_next_expanded(NULL); 313 return hd; 314 } else { 315 hd = res; 316 } 317 } 318 return NULL; 319 } 320 321 void SparsePRT::reset_for_cleanup_tasks() { 322 _head_expanded_list = NULL; 323 } 324 325 void SparsePRT::do_cleanup_work(SparsePRTCleanupTask* sprt_cleanup_task) { 326 if (should_be_on_expanded_list()) { 327 sprt_cleanup_task->add(this); 328 } 329 } 330 331 void SparsePRT::finish_cleanup_task(SparsePRTCleanupTask* sprt_cleanup_task) { 332 assert(ParGCRareEvent_lock->owned_by_self(), "pre-condition"); 333 SparsePRT* head = sprt_cleanup_task->head(); 334 SparsePRT* tail = sprt_cleanup_task->tail(); 335 if (head != NULL) { 336 assert(tail != NULL, "if head is not NULL, so should tail"); 337 338 tail->set_next_expanded(_head_expanded_list); 339 _head_expanded_list = head; 340 } else { 341 assert(tail == NULL, "if head is NULL, so should tail"); 342 } 343 } 344 345 bool SparsePRT::should_be_on_expanded_list() { 346 if (_expanded) { 347 assert(_cur != _next, "if _expanded is true, cur should be != _next"); 348 } else { 349 assert(_cur == _next, "if _expanded is false, cur should be == _next"); 350 } 351 return expanded(); 352 } 353 354 void SparsePRT::cleanup_all() { 355 // First clean up all expanded tables so they agree on next and cur. 356 SparsePRT* sprt = get_from_expanded_list(); 357 while (sprt != NULL) { 358 sprt->cleanup(); 359 sprt = get_from_expanded_list(); 360 } 361 } 362 363 364 SparsePRT::SparsePRT(HeapRegion* hr) : 365 _hr(hr), _expanded(false), _next_expanded(NULL) 366 { 367 _cur = new RSHashTable(InitialCapacity); 368 _next = _cur; 369 } 370 371 372 SparsePRT::~SparsePRT() { 373 assert(_next != NULL && _cur != NULL, "Inv"); 374 if (_cur != _next) { delete _cur; } 375 delete _next; 376 } 377 378 379 size_t SparsePRT::mem_size() const { 380 // We ignore "_cur" here, because it either = _next, or else it is 381 // on the deleted list. 382 return sizeof(SparsePRT) + _next->mem_size(); 383 } 384 385 bool SparsePRT::add_card(RegionIdx_t region_id, CardIdx_t card_index) { 386 if (_next->should_expand()) { 387 expand(); 388 } 389 return _next->add_card(region_id, card_index); 390 } 391 392 SparsePRTEntry* SparsePRT::get_entry(RegionIdx_t region_id) { 393 return _next->get_entry(region_id); 394 } 395 396 bool SparsePRT::delete_entry(RegionIdx_t region_id) { 397 return _next->delete_entry(region_id); 398 } 399 400 void SparsePRT::clear() { 401 // If they differ, _next is bigger then cur, so next has no chance of 402 // being the initial size. 403 if (_next != _cur) { 404 delete _next; 405 } 406 407 if (_cur->capacity() != InitialCapacity) { 408 delete _cur; 409 _cur = new RSHashTable(InitialCapacity); 410 } else { 411 _cur->clear(); 412 } 413 _next = _cur; 414 _expanded = false; 415 } 416 417 void SparsePRT::cleanup() { 418 // Make sure that the current and next tables agree. 419 if (_cur != _next) { 420 delete _cur; 421 } 422 _cur = _next; 423 set_expanded(false); 424 } 425 426 void SparsePRT::expand() { 427 RSHashTable* last = _next; 428 _next = new RSHashTable(last->capacity() * 2); 429 for (size_t i = 0; i < last->num_entries(); i++) { 430 SparsePRTEntry* e = last->entry((int)i); 431 if (e->valid_entry()) { 432 _next->add_entry(e); 433 } 434 } 435 if (last != _cur) { 436 delete last; 437 } 438 add_to_expanded_list(this); 439 } 440 441 void SparsePRTCleanupTask::add(SparsePRT* sprt) { 442 assert(sprt->should_be_on_expanded_list(), "pre-condition"); 443 444 sprt->set_next_expanded(NULL); 445 if (_tail != NULL) { 446 _tail->set_next_expanded(sprt); 447 } else { 448 _head = sprt; 449 } 450 _tail = sprt; 451 }