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/concurrentG1Refine.hpp" 27 #include "gc/g1/g1BlockOffsetTable.inline.hpp" 28 #include "gc/g1/g1CollectedHeap.inline.hpp" 29 #include "gc/g1/g1CardLiveData.inline.hpp" 30 #include "gc/g1/heapRegionManager.inline.hpp" 31 #include "gc/g1/heapRegionRemSet.hpp" 32 #include "gc/shared/space.inline.hpp" 33 #include "memory/allocation.hpp" 34 #include "memory/padded.inline.hpp" 35 #include "oops/oop.inline.hpp" 36 #include "runtime/atomic.inline.hpp" 37 #include "utilities/bitMap.inline.hpp" 38 #include "utilities/globalDefinitions.hpp" 39 #include "utilities/growableArray.hpp" 40 41 class PerRegionTable: public CHeapObj<mtGC> { 42 friend class OtherRegionsTable; 43 friend class HeapRegionRemSetIterator; 44 45 HeapRegion* _hr; 46 BitMap _bm; 47 jint _occupied; 48 49 // next pointer for free/allocated 'all' list 50 PerRegionTable* _next; 51 52 // prev pointer for the allocated 'all' list 53 PerRegionTable* _prev; 54 55 // next pointer in collision list 56 PerRegionTable * _collision_list_next; 57 58 // Global free list of PRTs 59 static PerRegionTable* _free_list; 60 61 protected: 62 // We need access in order to union things into the base table. 63 BitMap* bm() { return &_bm; } 64 65 void recount_occupied() { 66 _occupied = (jint) bm()->count_one_bits(); 67 } 68 69 PerRegionTable(HeapRegion* hr) : 70 _hr(hr), 71 _occupied(0), 72 _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */), 73 _collision_list_next(NULL), _next(NULL), _prev(NULL) 74 {} 75 76 void add_card_work(CardIdx_t from_card, bool par) { 77 if (!_bm.at(from_card)) { 78 if (par) { 79 if (_bm.par_at_put(from_card, 1)) { 80 Atomic::inc(&_occupied); 81 } 82 } else { 83 _bm.at_put(from_card, 1); 84 _occupied++; 85 } 86 } 87 } 88 89 void add_reference_work(OopOrNarrowOopStar from, bool par) { 90 // Must make this robust in case "from" is not in "_hr", because of 91 // concurrency. 92 93 HeapRegion* loc_hr = hr(); 94 // If the test below fails, then this table was reused concurrently 95 // with this operation. This is OK, since the old table was coarsened, 96 // and adding a bit to the new table is never incorrect. 97 // If the table used to belong to a continues humongous region and is 98 // now reused for the corresponding start humongous region, we need to 99 // make sure that we detect this. Thus, we call is_in_reserved_raw() 100 // instead of just is_in_reserved() here. 101 if (loc_hr->is_in_reserved(from)) { 102 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom()); 103 CardIdx_t from_card = (CardIdx_t) 104 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize); 105 106 assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion, 107 "Must be in range."); 108 add_card_work(from_card, par); 109 } 110 } 111 112 public: 113 114 HeapRegion* hr() const { 115 return (HeapRegion*) OrderAccess::load_ptr_acquire(&_hr); 116 } 117 118 jint occupied() const { 119 // Overkill, but if we ever need it... 120 // guarantee(_occupied == _bm.count_one_bits(), "Check"); 121 return _occupied; 122 } 123 124 void init(HeapRegion* hr, bool clear_links_to_all_list) { 125 if (clear_links_to_all_list) { 126 set_next(NULL); 127 set_prev(NULL); 128 } 129 _collision_list_next = NULL; 130 _occupied = 0; 131 _bm.clear(); 132 // Make sure that the bitmap clearing above has been finished before publishing 133 // this PRT to concurrent threads. 134 OrderAccess::release_store_ptr(&_hr, hr); 135 } 136 137 void add_reference(OopOrNarrowOopStar from) { 138 add_reference_work(from, /*parallel*/ true); 139 } 140 141 void seq_add_reference(OopOrNarrowOopStar from) { 142 add_reference_work(from, /*parallel*/ false); 143 } 144 145 void scrub(G1CardLiveData* live_data) { 146 live_data->remove_nonlive_cards(hr()->hrm_index(), &_bm); 147 recount_occupied(); 148 } 149 150 void add_card(CardIdx_t from_card_index) { 151 add_card_work(from_card_index, /*parallel*/ true); 152 } 153 154 void seq_add_card(CardIdx_t from_card_index) { 155 add_card_work(from_card_index, /*parallel*/ false); 156 } 157 158 // (Destructively) union the bitmap of the current table into the given 159 // bitmap (which is assumed to be of the same size.) 160 void union_bitmap_into(BitMap* bm) { 161 bm->set_union(_bm); 162 } 163 164 // Mem size in bytes. 165 size_t mem_size() const { 166 return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize; 167 } 168 169 // Requires "from" to be in "hr()". 170 bool contains_reference(OopOrNarrowOopStar from) const { 171 assert(hr()->is_in_reserved(from), "Precondition."); 172 size_t card_ind = pointer_delta(from, hr()->bottom(), 173 CardTableModRefBS::card_size); 174 return _bm.at(card_ind); 175 } 176 177 // Bulk-free the PRTs from prt to last, assumes that they are 178 // linked together using their _next field. 179 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) { 180 while (true) { 181 PerRegionTable* fl = _free_list; 182 last->set_next(fl); 183 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl); 184 if (res == fl) { 185 return; 186 } 187 } 188 ShouldNotReachHere(); 189 } 190 191 static void free(PerRegionTable* prt) { 192 bulk_free(prt, prt); 193 } 194 195 // Returns an initialized PerRegionTable instance. 196 static PerRegionTable* alloc(HeapRegion* hr) { 197 PerRegionTable* fl = _free_list; 198 while (fl != NULL) { 199 PerRegionTable* nxt = fl->next(); 200 PerRegionTable* res = 201 (PerRegionTable*) 202 Atomic::cmpxchg_ptr(nxt, &_free_list, fl); 203 if (res == fl) { 204 fl->init(hr, true); 205 return fl; 206 } else { 207 fl = _free_list; 208 } 209 } 210 assert(fl == NULL, "Loop condition."); 211 return new PerRegionTable(hr); 212 } 213 214 PerRegionTable* next() const { return _next; } 215 void set_next(PerRegionTable* next) { _next = next; } 216 PerRegionTable* prev() const { return _prev; } 217 void set_prev(PerRegionTable* prev) { _prev = prev; } 218 219 // Accessor and Modification routines for the pointer for the 220 // singly linked collision list that links the PRTs within the 221 // OtherRegionsTable::_fine_grain_regions hash table. 222 // 223 // It might be useful to also make the collision list doubly linked 224 // to avoid iteration over the collisions list during scrubbing/deletion. 225 // OTOH there might not be many collisions. 226 227 PerRegionTable* collision_list_next() const { 228 return _collision_list_next; 229 } 230 231 void set_collision_list_next(PerRegionTable* next) { 232 _collision_list_next = next; 233 } 234 235 PerRegionTable** collision_list_next_addr() { 236 return &_collision_list_next; 237 } 238 239 static size_t fl_mem_size() { 240 PerRegionTable* cur = _free_list; 241 size_t res = 0; 242 while (cur != NULL) { 243 res += cur->mem_size(); 244 cur = cur->next(); 245 } 246 return res; 247 } 248 249 static void test_fl_mem_size(); 250 }; 251 252 PerRegionTable* PerRegionTable::_free_list = NULL; 253 254 size_t OtherRegionsTable::_max_fine_entries = 0; 255 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0; 256 size_t OtherRegionsTable::_fine_eviction_stride = 0; 257 size_t OtherRegionsTable::_fine_eviction_sample_size = 0; 258 259 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) : 260 _g1h(G1CollectedHeap::heap()), 261 _hr(hr), _m(m), 262 _coarse_map(G1CollectedHeap::heap()->max_regions(), 263 false /* in-resource-area */), 264 _fine_grain_regions(NULL), 265 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL), 266 _n_fine_entries(0), _n_coarse_entries(0), 267 _fine_eviction_start(0), 268 _sparse_table(hr), 269 _coarse_dirty(false) 270 { 271 typedef PerRegionTable* PerRegionTablePtr; 272 273 if (_max_fine_entries == 0) { 274 assert(_mod_max_fine_entries_mask == 0, "Both or none."); 275 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries); 276 _max_fine_entries = (size_t)1 << max_entries_log; 277 _mod_max_fine_entries_mask = _max_fine_entries - 1; 278 279 assert(_fine_eviction_sample_size == 0 280 && _fine_eviction_stride == 0, "All init at same time."); 281 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log); 282 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size; 283 } 284 285 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries, 286 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 287 288 if (_fine_grain_regions == NULL) { 289 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR, 290 "Failed to allocate _fine_grain_entries."); 291 } 292 293 for (size_t i = 0; i < _max_fine_entries; i++) { 294 _fine_grain_regions[i] = NULL; 295 } 296 } 297 298 void OtherRegionsTable::link_to_all(PerRegionTable* prt) { 299 // We always append to the beginning of the list for convenience; 300 // the order of entries in this list does not matter. 301 if (_first_all_fine_prts != NULL) { 302 assert(_first_all_fine_prts->prev() == NULL, "invariant"); 303 _first_all_fine_prts->set_prev(prt); 304 prt->set_next(_first_all_fine_prts); 305 } else { 306 // this is the first element we insert. Adjust the "last" pointer 307 _last_all_fine_prts = prt; 308 assert(prt->next() == NULL, "just checking"); 309 } 310 // the new element is always the first element without a predecessor 311 prt->set_prev(NULL); 312 _first_all_fine_prts = prt; 313 314 assert(prt->prev() == NULL, "just checking"); 315 assert(_first_all_fine_prts == prt, "just checking"); 316 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 317 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 318 "just checking"); 319 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 320 "just checking"); 321 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 322 "just checking"); 323 } 324 325 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) { 326 if (prt->prev() != NULL) { 327 assert(_first_all_fine_prts != prt, "just checking"); 328 prt->prev()->set_next(prt->next()); 329 // removing the last element in the list? 330 if (_last_all_fine_prts == prt) { 331 _last_all_fine_prts = prt->prev(); 332 } 333 } else { 334 assert(_first_all_fine_prts == prt, "just checking"); 335 _first_all_fine_prts = prt->next(); 336 // list is empty now? 337 if (_first_all_fine_prts == NULL) { 338 _last_all_fine_prts = NULL; 339 } 340 } 341 342 if (prt->next() != NULL) { 343 prt->next()->set_prev(prt->prev()); 344 } 345 346 prt->set_next(NULL); 347 prt->set_prev(NULL); 348 349 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 350 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 351 "just checking"); 352 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 353 "just checking"); 354 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 355 "just checking"); 356 } 357 358 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, uint tid) { 359 uint cur_hrm_ind = _hr->hrm_index(); 360 361 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift); 362 363 if (G1FromCardCache::contains_or_replace(tid, cur_hrm_ind, from_card)) { 364 assert(contains_reference(from), "We just found " PTR_FORMAT " in the FromCardCache", p2i(from)); 365 return; 366 } 367 368 // Note that this may be a continued H region. 369 HeapRegion* from_hr = _g1h->heap_region_containing(from); 370 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index(); 371 372 // If the region is already coarsened, return. 373 if (_coarse_map.at(from_hrm_ind)) { 374 assert(contains_reference(from), "We just found " PTR_FORMAT " in the Coarse table", p2i(from)); 375 return; 376 } 377 378 // Otherwise find a per-region table to add it to. 379 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask; 380 PerRegionTable* prt = find_region_table(ind, from_hr); 381 if (prt == NULL) { 382 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag); 383 // Confirm that it's really not there... 384 prt = find_region_table(ind, from_hr); 385 if (prt == NULL) { 386 387 uintptr_t from_hr_bot_card_index = 388 uintptr_t(from_hr->bottom()) 389 >> CardTableModRefBS::card_shift; 390 CardIdx_t card_index = from_card - from_hr_bot_card_index; 391 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion, 392 "Must be in range."); 393 if (G1HRRSUseSparseTable && 394 _sparse_table.add_card(from_hrm_ind, card_index)) { 395 assert(contains_reference_locked(from), "We just added " PTR_FORMAT " to the Sparse table", p2i(from)); 396 return; 397 } 398 399 if (_n_fine_entries == _max_fine_entries) { 400 prt = delete_region_table(); 401 // There is no need to clear the links to the 'all' list here: 402 // prt will be reused immediately, i.e. remain in the 'all' list. 403 prt->init(from_hr, false /* clear_links_to_all_list */); 404 } else { 405 prt = PerRegionTable::alloc(from_hr); 406 link_to_all(prt); 407 } 408 409 PerRegionTable* first_prt = _fine_grain_regions[ind]; 410 prt->set_collision_list_next(first_prt); 411 // The assignment into _fine_grain_regions allows the prt to 412 // start being used concurrently. In addition to 413 // collision_list_next which must be visible (else concurrent 414 // parsing of the list, if any, may fail to see other entries), 415 // the content of the prt must be visible (else for instance 416 // some mark bits may not yet seem cleared or a 'later' update 417 // performed by a concurrent thread could be undone when the 418 // zeroing becomes visible). This requires store ordering. 419 OrderAccess::release_store_ptr((volatile PerRegionTable*)&_fine_grain_regions[ind], prt); 420 _n_fine_entries++; 421 422 if (G1HRRSUseSparseTable) { 423 // Transfer from sparse to fine-grain. 424 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind); 425 assert(sprt_entry != NULL, "There should have been an entry"); 426 for (int i = 0; i < SparsePRTEntry::cards_num(); i++) { 427 CardIdx_t c = sprt_entry->card(i); 428 if (c != SparsePRTEntry::NullEntry) { 429 prt->add_card(c); 430 } 431 } 432 // Now we can delete the sparse entry. 433 bool res = _sparse_table.delete_entry(from_hrm_ind); 434 assert(res, "It should have been there."); 435 } 436 } 437 assert(prt != NULL && prt->hr() == from_hr, "consequence"); 438 } 439 // Note that we can't assert "prt->hr() == from_hr", because of the 440 // possibility of concurrent reuse. But see head comment of 441 // OtherRegionsTable for why this is OK. 442 assert(prt != NULL, "Inv"); 443 444 prt->add_reference(from); 445 assert(contains_reference(from), "We just added " PTR_FORMAT " to the PRT", p2i(from)); 446 } 447 448 PerRegionTable* 449 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const { 450 assert(ind < _max_fine_entries, "Preconditions."); 451 PerRegionTable* prt = _fine_grain_regions[ind]; 452 while (prt != NULL && prt->hr() != hr) { 453 prt = prt->collision_list_next(); 454 } 455 // Loop postcondition is the method postcondition. 456 return prt; 457 } 458 459 jint OtherRegionsTable::_n_coarsenings = 0; 460 461 PerRegionTable* OtherRegionsTable::delete_region_table() { 462 assert(_m->owned_by_self(), "Precondition"); 463 assert(_n_fine_entries == _max_fine_entries, "Precondition"); 464 PerRegionTable* max = NULL; 465 jint max_occ = 0; 466 PerRegionTable** max_prev = NULL; 467 size_t max_ind; 468 469 size_t i = _fine_eviction_start; 470 for (size_t k = 0; k < _fine_eviction_sample_size; k++) { 471 size_t ii = i; 472 // Make sure we get a non-NULL sample. 473 while (_fine_grain_regions[ii] == NULL) { 474 ii++; 475 if (ii == _max_fine_entries) ii = 0; 476 guarantee(ii != i, "We must find one."); 477 } 478 PerRegionTable** prev = &_fine_grain_regions[ii]; 479 PerRegionTable* cur = *prev; 480 while (cur != NULL) { 481 jint cur_occ = cur->occupied(); 482 if (max == NULL || cur_occ > max_occ) { 483 max = cur; 484 max_prev = prev; 485 max_ind = i; 486 max_occ = cur_occ; 487 } 488 prev = cur->collision_list_next_addr(); 489 cur = cur->collision_list_next(); 490 } 491 i = i + _fine_eviction_stride; 492 if (i >= _n_fine_entries) i = i - _n_fine_entries; 493 } 494 495 _fine_eviction_start++; 496 497 if (_fine_eviction_start >= _n_fine_entries) { 498 _fine_eviction_start -= _n_fine_entries; 499 } 500 501 guarantee(max != NULL, "Since _n_fine_entries > 0"); 502 guarantee(max_prev != NULL, "Since max != NULL."); 503 504 // Set the corresponding coarse bit. 505 size_t max_hrm_index = (size_t) max->hr()->hrm_index(); 506 if (!_coarse_map.at(max_hrm_index)) { 507 _coarse_map.at_put(max_hrm_index, true); 508 _coarse_dirty = true; 509 _n_coarse_entries++; 510 } 511 512 // Unsplice. 513 *max_prev = max->collision_list_next(); 514 Atomic::inc(&_n_coarsenings); 515 _n_fine_entries--; 516 return max; 517 } 518 519 void OtherRegionsTable::scrub(G1CardLiveData* live_data) { 520 // First eliminated garbage regions from the coarse map. 521 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index()); 522 523 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries); 524 if (_coarse_dirty) { 525 live_data->remove_nonlive_regions(&_coarse_map); 526 _n_coarse_entries = _coarse_map.count_one_bits(); 527 _coarse_dirty = _n_coarse_entries != 0; 528 } 529 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries); 530 531 // Now do the fine-grained maps. 532 for (size_t i = 0; i < _max_fine_entries; i++) { 533 PerRegionTable* cur = _fine_grain_regions[i]; 534 PerRegionTable** prev = &_fine_grain_regions[i]; 535 while (cur != NULL) { 536 PerRegionTable* nxt = cur->collision_list_next(); 537 // If the entire region is dead, eliminate. 538 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index()); 539 if (!live_data->is_region_live(cur->hr()->hrm_index())) { 540 *prev = nxt; 541 cur->set_collision_list_next(NULL); 542 _n_fine_entries--; 543 log_develop_trace(gc, remset, scrub)(" deleted via region map."); 544 unlink_from_all(cur); 545 PerRegionTable::free(cur); 546 } else { 547 // Do fine-grain elimination. 548 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied()); 549 cur->scrub(live_data); 550 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied()); 551 // Did that empty the table completely? 552 if (cur->occupied() == 0) { 553 *prev = nxt; 554 cur->set_collision_list_next(NULL); 555 _n_fine_entries--; 556 unlink_from_all(cur); 557 PerRegionTable::free(cur); 558 } else { 559 prev = cur->collision_list_next_addr(); 560 } 561 } 562 cur = nxt; 563 } 564 } 565 // Since we may have deleted a from_card_cache entry from the RS, clear 566 // the FCC. 567 clear_fcc(); 568 } 569 570 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const { 571 if (limit <= (size_t)G1RSetSparseRegionEntries) { 572 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit; 573 } else { 574 // Current uses of this method may only use values less than G1RSetSparseRegionEntries 575 // for the limit. The solution, comparing against occupied() would be too slow 576 // at this time. 577 Unimplemented(); 578 return false; 579 } 580 } 581 582 bool OtherRegionsTable::is_empty() const { 583 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL; 584 } 585 586 size_t OtherRegionsTable::occupied() const { 587 size_t sum = occ_fine(); 588 sum += occ_sparse(); 589 sum += occ_coarse(); 590 return sum; 591 } 592 593 size_t OtherRegionsTable::occ_fine() const { 594 size_t sum = 0; 595 596 size_t num = 0; 597 PerRegionTable * cur = _first_all_fine_prts; 598 while (cur != NULL) { 599 sum += cur->occupied(); 600 cur = cur->next(); 601 num++; 602 } 603 guarantee(num == _n_fine_entries, "just checking"); 604 return sum; 605 } 606 607 size_t OtherRegionsTable::occ_coarse() const { 608 return (_n_coarse_entries * HeapRegion::CardsPerRegion); 609 } 610 611 size_t OtherRegionsTable::occ_sparse() const { 612 return _sparse_table.occupied(); 613 } 614 615 size_t OtherRegionsTable::mem_size() const { 616 size_t sum = 0; 617 // all PRTs are of the same size so it is sufficient to query only one of them. 618 if (_first_all_fine_prts != NULL) { 619 assert(_last_all_fine_prts != NULL && 620 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant"); 621 sum += _first_all_fine_prts->mem_size() * _n_fine_entries; 622 } 623 sum += (sizeof(PerRegionTable*) * _max_fine_entries); 624 sum += (_coarse_map.size_in_words() * HeapWordSize); 625 sum += (_sparse_table.mem_size()); 626 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above. 627 return sum; 628 } 629 630 size_t OtherRegionsTable::static_mem_size() { 631 return G1FromCardCache::static_mem_size(); 632 } 633 634 size_t OtherRegionsTable::fl_mem_size() { 635 return PerRegionTable::fl_mem_size(); 636 } 637 638 void OtherRegionsTable::clear_fcc() { 639 G1FromCardCache::clear(_hr->hrm_index()); 640 } 641 642 void OtherRegionsTable::clear() { 643 // if there are no entries, skip this step 644 if (_first_all_fine_prts != NULL) { 645 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking"); 646 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts); 647 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0])); 648 } else { 649 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking"); 650 } 651 652 _first_all_fine_prts = _last_all_fine_prts = NULL; 653 _sparse_table.clear(); 654 if (_coarse_dirty) { 655 _coarse_map.clear(); 656 _coarse_dirty = false; 657 } 658 _n_fine_entries = 0; 659 _n_coarse_entries = 0; 660 661 clear_fcc(); 662 } 663 664 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const { 665 // Cast away const in this case. 666 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag); 667 return contains_reference_locked(from); 668 } 669 670 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const { 671 HeapRegion* hr = _g1h->heap_region_containing(from); 672 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index(); 673 // Is this region in the coarse map? 674 if (_coarse_map.at(hr_ind)) return true; 675 676 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask, 677 hr); 678 if (prt != NULL) { 679 return prt->contains_reference(from); 680 681 } else { 682 uintptr_t from_card = 683 (uintptr_t(from) >> CardTableModRefBS::card_shift); 684 uintptr_t hr_bot_card_index = 685 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift; 686 assert(from_card >= hr_bot_card_index, "Inv"); 687 CardIdx_t card_index = from_card - hr_bot_card_index; 688 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion, 689 "Must be in range."); 690 return _sparse_table.contains_card(hr_ind, card_index); 691 } 692 } 693 694 void 695 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 696 _sparse_table.do_cleanup_work(hrrs_cleanup_task); 697 } 698 699 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetTable* bot, 700 HeapRegion* hr) 701 : _bot(bot), 702 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never), 703 _code_roots(), 704 _other_regions(hr, &_m) { 705 } 706 707 void HeapRegionRemSet::setup_remset_size() { 708 // Setup sparse and fine-grain tables sizes. 709 // table_size = base * (log(region_size / 1M) + 1) 710 const int LOG_M = 20; 711 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0); 712 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) { 713 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1); 714 } 715 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) { 716 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1); 717 } 718 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity"); 719 } 720 721 #ifndef PRODUCT 722 void HeapRegionRemSet::print() { 723 HeapRegionRemSetIterator iter(this); 724 size_t card_index; 725 while (iter.has_next(card_index)) { 726 HeapWord* card_start = _bot->address_for_index(card_index); 727 tty->print_cr(" Card " PTR_FORMAT, p2i(card_start)); 728 } 729 if (iter.n_yielded() != occupied()) { 730 tty->print_cr("Yielded disagrees with occupied:"); 731 tty->print_cr(" " SIZE_FORMAT_W(6) " yielded (" SIZE_FORMAT_W(6) 732 " coarse, " SIZE_FORMAT_W(6) " fine).", 733 iter.n_yielded(), 734 iter.n_yielded_coarse(), iter.n_yielded_fine()); 735 tty->print_cr(" " SIZE_FORMAT_W(6) " occ (" SIZE_FORMAT_W(6) 736 " coarse, " SIZE_FORMAT_W(6) " fine).", 737 occupied(), occ_coarse(), occ_fine()); 738 } 739 guarantee(iter.n_yielded() == occupied(), 740 "We should have yielded all the represented cards."); 741 } 742 #endif 743 744 void HeapRegionRemSet::cleanup() { 745 SparsePRT::cleanup_all(); 746 } 747 748 void HeapRegionRemSet::clear() { 749 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); 750 clear_locked(); 751 } 752 753 void HeapRegionRemSet::clear_locked() { 754 _code_roots.clear(); 755 _other_regions.clear(); 756 assert(occupied_locked() == 0, "Should be clear."); 757 } 758 759 void HeapRegionRemSet::scrub(G1CardLiveData* live_data) { 760 _other_regions.scrub(live_data); 761 } 762 763 // Code roots support 764 // 765 // The code root set is protected by two separate locking schemes 766 // When at safepoint the per-hrrs lock must be held during modifications 767 // except when doing a full gc. 768 // When not at safepoint the CodeCache_lock must be held during modifications. 769 // When concurrent readers access the contains() function 770 // (during the evacuation phase) no removals are allowed. 771 772 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) { 773 assert(nm != NULL, "sanity"); 774 assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()), 775 "should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s", 776 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint())); 777 // Optimistic unlocked contains-check 778 if (!_code_roots.contains(nm)) { 779 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag); 780 add_strong_code_root_locked(nm); 781 } 782 } 783 784 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) { 785 assert(nm != NULL, "sanity"); 786 assert((CodeCache_lock->owned_by_self() || 787 (SafepointSynchronize::is_at_safepoint() && 788 (_m.owned_by_self() || Thread::current()->is_VM_thread()))), 789 "not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s", 790 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), 791 BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread())); 792 _code_roots.add(nm); 793 } 794 795 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) { 796 assert(nm != NULL, "sanity"); 797 assert_locked_or_safepoint(CodeCache_lock); 798 799 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag); 800 _code_roots.remove(nm); 801 802 // Check that there were no duplicates 803 guarantee(!_code_roots.contains(nm), "duplicate entry found"); 804 } 805 806 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const { 807 _code_roots.nmethods_do(blk); 808 } 809 810 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) { 811 _code_roots.clean(hr); 812 } 813 814 size_t HeapRegionRemSet::strong_code_roots_mem_size() { 815 return _code_roots.mem_size(); 816 } 817 818 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) : 819 _hrrs(hrrs), 820 _g1h(G1CollectedHeap::heap()), 821 _coarse_map(&hrrs->_other_regions._coarse_map), 822 _bot(hrrs->_bot), 823 _is(Sparse), 824 // Set these values so that we increment to the first region. 825 _coarse_cur_region_index(-1), 826 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1), 827 _cur_card_in_prt(HeapRegion::CardsPerRegion), 828 _fine_cur_prt(NULL), 829 _n_yielded_coarse(0), 830 _n_yielded_fine(0), 831 _n_yielded_sparse(0), 832 _sparse_iter(&hrrs->_other_regions._sparse_table) {} 833 834 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) { 835 if (_hrrs->_other_regions._n_coarse_entries == 0) return false; 836 // Go to the next card. 837 _coarse_cur_region_cur_card++; 838 // Was the last the last card in the current region? 839 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) { 840 // Yes: find the next region. This may leave _coarse_cur_region_index 841 // Set to the last index, in which case there are no more coarse 842 // regions. 843 _coarse_cur_region_index = 844 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1); 845 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) { 846 _coarse_cur_region_cur_card = 0; 847 HeapWord* r_bot = 848 _g1h->region_at((uint) _coarse_cur_region_index)->bottom(); 849 _cur_region_card_offset = _bot->index_for(r_bot); 850 } else { 851 return false; 852 } 853 } 854 // If we didn't return false above, then we can yield a card. 855 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card; 856 return true; 857 } 858 859 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) { 860 if (fine_has_next()) { 861 _cur_card_in_prt = 862 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 863 } 864 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) { 865 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for 866 // the remembered set. 867 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) { 868 return false; 869 } 870 PerRegionTable* next_prt = _fine_cur_prt->next(); 871 switch_to_prt(next_prt); 872 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 873 } 874 875 card_index = _cur_region_card_offset + _cur_card_in_prt; 876 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion, 877 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt); 878 return true; 879 } 880 881 bool HeapRegionRemSetIterator::fine_has_next() { 882 return _cur_card_in_prt != HeapRegion::CardsPerRegion; 883 } 884 885 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) { 886 assert(prt != NULL, "Cannot switch to NULL prt"); 887 _fine_cur_prt = prt; 888 889 HeapWord* r_bot = _fine_cur_prt->hr()->bottom(); 890 _cur_region_card_offset = _bot->index_for(r_bot); 891 892 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1. 893 // To avoid special-casing this start case, and not miss the first bitmap 894 // entry, initialize _cur_region_cur_card with -1 instead of 0. 895 _cur_card_in_prt = (size_t)-1; 896 } 897 898 bool HeapRegionRemSetIterator::has_next(size_t& card_index) { 899 switch (_is) { 900 case Sparse: { 901 if (_sparse_iter.has_next(card_index)) { 902 _n_yielded_sparse++; 903 return true; 904 } 905 // Otherwise, deliberate fall-through 906 _is = Fine; 907 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts; 908 if (initial_fine_prt != NULL) { 909 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts); 910 } 911 } 912 case Fine: 913 if (fine_has_next(card_index)) { 914 _n_yielded_fine++; 915 return true; 916 } 917 // Otherwise, deliberate fall-through 918 _is = Coarse; 919 case Coarse: 920 if (coarse_has_next(card_index)) { 921 _n_yielded_coarse++; 922 return true; 923 } 924 // Otherwise... 925 break; 926 } 927 assert(ParallelGCThreads > 1 || 928 n_yielded() == _hrrs->occupied(), 929 "Should have yielded all the cards in the rem set " 930 "(in the non-par case)."); 931 return false; 932 } 933 934 void HeapRegionRemSet::reset_for_cleanup_tasks() { 935 SparsePRT::reset_for_cleanup_tasks(); 936 } 937 938 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 939 _other_regions.do_cleanup_work(hrrs_cleanup_task); 940 } 941 942 void 943 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) { 944 SparsePRT::finish_cleanup_task(hrrs_cleanup_task); 945 } 946 947 #ifndef PRODUCT 948 void HeapRegionRemSet::test() { 949 os::sleep(Thread::current(), (jlong)5000, false); 950 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 951 952 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same 953 // hash bucket. 954 HeapRegion* hr0 = g1h->region_at(0); 955 HeapRegion* hr1 = g1h->region_at(1); 956 HeapRegion* hr2 = g1h->region_at(5); 957 HeapRegion* hr3 = g1h->region_at(6); 958 HeapRegion* hr4 = g1h->region_at(7); 959 HeapRegion* hr5 = g1h->region_at(8); 960 961 HeapWord* hr1_start = hr1->bottom(); 962 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2; 963 HeapWord* hr1_last = hr1->end() - 1; 964 965 HeapWord* hr2_start = hr2->bottom(); 966 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2; 967 HeapWord* hr2_last = hr2->end() - 1; 968 969 HeapWord* hr3_start = hr3->bottom(); 970 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2; 971 HeapWord* hr3_last = hr3->end() - 1; 972 973 HeapRegionRemSet* hrrs = hr0->rem_set(); 974 975 // Make three references from region 0x101... 976 hrrs->add_reference((OopOrNarrowOopStar)hr1_start); 977 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid); 978 hrrs->add_reference((OopOrNarrowOopStar)hr1_last); 979 980 hrrs->add_reference((OopOrNarrowOopStar)hr2_start); 981 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid); 982 hrrs->add_reference((OopOrNarrowOopStar)hr2_last); 983 984 hrrs->add_reference((OopOrNarrowOopStar)hr3_start); 985 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid); 986 hrrs->add_reference((OopOrNarrowOopStar)hr3_last); 987 988 // Now cause a coarsening. 989 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom()); 990 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom()); 991 992 // Now, does iteration yield these three? 993 HeapRegionRemSetIterator iter(hrrs); 994 size_t sum = 0; 995 size_t card_index; 996 while (iter.has_next(card_index)) { 997 HeapWord* card_start = 998 G1CollectedHeap::heap()->bot()->address_for_index(card_index); 999 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start)); 1000 sum++; 1001 } 1002 guarantee(sum == 11 - 3 + 2048, "Failure"); 1003 guarantee(sum == hrrs->occupied(), "Failure"); 1004 } 1005 #endif