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* volatile _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* volatile 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 { 270 typedef PerRegionTable* PerRegionTablePtr; 271 272 if (_max_fine_entries == 0) { 273 assert(_mod_max_fine_entries_mask == 0, "Both or none."); 274 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries); 275 _max_fine_entries = (size_t)1 << max_entries_log; 276 _mod_max_fine_entries_mask = _max_fine_entries - 1; 277 278 assert(_fine_eviction_sample_size == 0 279 && _fine_eviction_stride == 0, "All init at same time."); 280 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log); 281 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size; 282 } 283 284 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries, 285 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 286 287 if (_fine_grain_regions == NULL) { 288 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR, 289 "Failed to allocate _fine_grain_entries."); 290 } 291 292 for (size_t i = 0; i < _max_fine_entries; i++) { 293 _fine_grain_regions[i] = NULL; 294 } 295 } 296 297 void OtherRegionsTable::link_to_all(PerRegionTable* prt) { 298 // We always append to the beginning of the list for convenience; 299 // the order of entries in this list does not matter. 300 if (_first_all_fine_prts != NULL) { 301 assert(_first_all_fine_prts->prev() == NULL, "invariant"); 302 _first_all_fine_prts->set_prev(prt); 303 prt->set_next(_first_all_fine_prts); 304 } else { 305 // this is the first element we insert. Adjust the "last" pointer 306 _last_all_fine_prts = prt; 307 assert(prt->next() == NULL, "just checking"); 308 } 309 // the new element is always the first element without a predecessor 310 prt->set_prev(NULL); 311 _first_all_fine_prts = prt; 312 313 assert(prt->prev() == NULL, "just checking"); 314 assert(_first_all_fine_prts == prt, "just checking"); 315 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 316 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 317 "just checking"); 318 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 319 "just checking"); 320 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 321 "just checking"); 322 } 323 324 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) { 325 if (prt->prev() != NULL) { 326 assert(_first_all_fine_prts != prt, "just checking"); 327 prt->prev()->set_next(prt->next()); 328 // removing the last element in the list? 329 if (_last_all_fine_prts == prt) { 330 _last_all_fine_prts = prt->prev(); 331 } 332 } else { 333 assert(_first_all_fine_prts == prt, "just checking"); 334 _first_all_fine_prts = prt->next(); 335 // list is empty now? 336 if (_first_all_fine_prts == NULL) { 337 _last_all_fine_prts = NULL; 338 } 339 } 340 341 if (prt->next() != NULL) { 342 prt->next()->set_prev(prt->prev()); 343 } 344 345 prt->set_next(NULL); 346 prt->set_prev(NULL); 347 348 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 349 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 350 "just checking"); 351 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 352 "just checking"); 353 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 354 "just checking"); 355 } 356 357 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, uint tid) { 358 uint cur_hrm_ind = _hr->hrm_index(); 359 360 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift); 361 362 if (G1FromCardCache::contains_or_replace(tid, cur_hrm_ind, from_card)) { 363 assert(contains_reference(from), "We just found " PTR_FORMAT " in the FromCardCache", p2i(from)); 364 return; 365 } 366 367 // Note that this may be a continued H region. 368 HeapRegion* from_hr = _g1h->heap_region_containing(from); 369 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index(); 370 371 // If the region is already coarsened, return. 372 if (_coarse_map.at(from_hrm_ind)) { 373 assert(contains_reference(from), "We just found " PTR_FORMAT " in the Coarse table", p2i(from)); 374 return; 375 } 376 377 // Otherwise find a per-region table to add it to. 378 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask; 379 PerRegionTable* prt = find_region_table(ind, from_hr); 380 if (prt == NULL) { 381 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag); 382 // Confirm that it's really not there... 383 prt = find_region_table(ind, from_hr); 384 if (prt == NULL) { 385 386 uintptr_t from_hr_bot_card_index = 387 uintptr_t(from_hr->bottom()) 388 >> CardTableModRefBS::card_shift; 389 CardIdx_t card_index = from_card - from_hr_bot_card_index; 390 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion, 391 "Must be in range."); 392 if (G1HRRSUseSparseTable && 393 _sparse_table.add_card(from_hrm_ind, card_index)) { 394 assert(contains_reference_locked(from), "We just added " PTR_FORMAT " to the Sparse table", p2i(from)); 395 return; 396 } 397 398 if (_n_fine_entries == _max_fine_entries) { 399 prt = delete_region_table(); 400 // There is no need to clear the links to the 'all' list here: 401 // prt will be reused immediately, i.e. remain in the 'all' list. 402 prt->init(from_hr, false /* clear_links_to_all_list */); 403 } else { 404 prt = PerRegionTable::alloc(from_hr); 405 link_to_all(prt); 406 } 407 408 PerRegionTable* first_prt = _fine_grain_regions[ind]; 409 prt->set_collision_list_next(first_prt); 410 // The assignment into _fine_grain_regions allows the prt to 411 // start being used concurrently. In addition to 412 // collision_list_next which must be visible (else concurrent 413 // parsing of the list, if any, may fail to see other entries), 414 // the content of the prt must be visible (else for instance 415 // some mark bits may not yet seem cleared or a 'later' update 416 // performed by a concurrent thread could be undone when the 417 // zeroing becomes visible). This requires store ordering. 418 OrderAccess::release_store_ptr((volatile PerRegionTable*)&_fine_grain_regions[ind], prt); 419 _n_fine_entries++; 420 421 if (G1HRRSUseSparseTable) { 422 // Transfer from sparse to fine-grain. 423 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind); 424 assert(sprt_entry != NULL, "There should have been an entry"); 425 for (int i = 0; i < SparsePRTEntry::cards_num(); i++) { 426 CardIdx_t c = sprt_entry->card(i); 427 if (c != SparsePRTEntry::NullEntry) { 428 prt->add_card(c); 429 } 430 } 431 // Now we can delete the sparse entry. 432 bool res = _sparse_table.delete_entry(from_hrm_ind); 433 assert(res, "It should have been there."); 434 } 435 } 436 assert(prt != NULL && prt->hr() == from_hr, "consequence"); 437 } 438 // Note that we can't assert "prt->hr() == from_hr", because of the 439 // possibility of concurrent reuse. But see head comment of 440 // OtherRegionsTable for why this is OK. 441 assert(prt != NULL, "Inv"); 442 443 prt->add_reference(from); 444 assert(contains_reference(from), "We just added " PTR_FORMAT " to the PRT", p2i(from)); 445 } 446 447 PerRegionTable* 448 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const { 449 assert(ind < _max_fine_entries, "Preconditions."); 450 PerRegionTable* prt = _fine_grain_regions[ind]; 451 while (prt != NULL && prt->hr() != hr) { 452 prt = prt->collision_list_next(); 453 } 454 // Loop postcondition is the method postcondition. 455 return prt; 456 } 457 458 jint OtherRegionsTable::_n_coarsenings = 0; 459 460 PerRegionTable* OtherRegionsTable::delete_region_table() { 461 assert(_m->owned_by_self(), "Precondition"); 462 assert(_n_fine_entries == _max_fine_entries, "Precondition"); 463 PerRegionTable* max = NULL; 464 jint max_occ = 0; 465 PerRegionTable** max_prev = NULL; 466 size_t max_ind; 467 468 size_t i = _fine_eviction_start; 469 for (size_t k = 0; k < _fine_eviction_sample_size; k++) { 470 size_t ii = i; 471 // Make sure we get a non-NULL sample. 472 while (_fine_grain_regions[ii] == NULL) { 473 ii++; 474 if (ii == _max_fine_entries) ii = 0; 475 guarantee(ii != i, "We must find one."); 476 } 477 PerRegionTable** prev = &_fine_grain_regions[ii]; 478 PerRegionTable* cur = *prev; 479 while (cur != NULL) { 480 jint cur_occ = cur->occupied(); 481 if (max == NULL || cur_occ > max_occ) { 482 max = cur; 483 max_prev = prev; 484 max_ind = i; 485 max_occ = cur_occ; 486 } 487 prev = cur->collision_list_next_addr(); 488 cur = cur->collision_list_next(); 489 } 490 i = i + _fine_eviction_stride; 491 if (i >= _n_fine_entries) i = i - _n_fine_entries; 492 } 493 494 _fine_eviction_start++; 495 496 if (_fine_eviction_start >= _n_fine_entries) { 497 _fine_eviction_start -= _n_fine_entries; 498 } 499 500 guarantee(max != NULL, "Since _n_fine_entries > 0"); 501 guarantee(max_prev != NULL, "Since max != NULL."); 502 503 // Set the corresponding coarse bit. 504 size_t max_hrm_index = (size_t) max->hr()->hrm_index(); 505 if (!_coarse_map.at(max_hrm_index)) { 506 _coarse_map.at_put(max_hrm_index, true); 507 _n_coarse_entries++; 508 } 509 510 // Unsplice. 511 *max_prev = max->collision_list_next(); 512 Atomic::inc(&_n_coarsenings); 513 _n_fine_entries--; 514 return max; 515 } 516 517 void OtherRegionsTable::scrub(G1CardLiveData* live_data) { 518 // First eliminated garbage regions from the coarse map. 519 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index()); 520 521 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries); 522 live_data->remove_nonlive_regions(&_coarse_map); 523 _n_coarse_entries = _coarse_map.count_one_bits(); 524 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries); 525 526 // Now do the fine-grained maps. 527 for (size_t i = 0; i < _max_fine_entries; i++) { 528 PerRegionTable* cur = _fine_grain_regions[i]; 529 PerRegionTable** prev = &_fine_grain_regions[i]; 530 while (cur != NULL) { 531 PerRegionTable* nxt = cur->collision_list_next(); 532 // If the entire region is dead, eliminate. 533 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index()); 534 if (!live_data->is_region_live(cur->hr()->hrm_index())) { 535 *prev = nxt; 536 cur->set_collision_list_next(NULL); 537 _n_fine_entries--; 538 log_develop_trace(gc, remset, scrub)(" deleted via region map."); 539 unlink_from_all(cur); 540 PerRegionTable::free(cur); 541 } else { 542 // Do fine-grain elimination. 543 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied()); 544 cur->scrub(live_data); 545 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied()); 546 // Did that empty the table completely? 547 if (cur->occupied() == 0) { 548 *prev = nxt; 549 cur->set_collision_list_next(NULL); 550 _n_fine_entries--; 551 unlink_from_all(cur); 552 PerRegionTable::free(cur); 553 } else { 554 prev = cur->collision_list_next_addr(); 555 } 556 } 557 cur = nxt; 558 } 559 } 560 // Since we may have deleted a from_card_cache entry from the RS, clear 561 // the FCC. 562 clear_fcc(); 563 } 564 565 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const { 566 if (limit <= (size_t)G1RSetSparseRegionEntries) { 567 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit; 568 } else { 569 // Current uses of this method may only use values less than G1RSetSparseRegionEntries 570 // for the limit. The solution, comparing against occupied() would be too slow 571 // at this time. 572 Unimplemented(); 573 return false; 574 } 575 } 576 577 bool OtherRegionsTable::is_empty() const { 578 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL; 579 } 580 581 size_t OtherRegionsTable::occupied() const { 582 size_t sum = occ_fine(); 583 sum += occ_sparse(); 584 sum += occ_coarse(); 585 return sum; 586 } 587 588 size_t OtherRegionsTable::occ_fine() const { 589 size_t sum = 0; 590 591 size_t num = 0; 592 PerRegionTable * cur = _first_all_fine_prts; 593 while (cur != NULL) { 594 sum += cur->occupied(); 595 cur = cur->next(); 596 num++; 597 } 598 guarantee(num == _n_fine_entries, "just checking"); 599 return sum; 600 } 601 602 size_t OtherRegionsTable::occ_coarse() const { 603 return (_n_coarse_entries * HeapRegion::CardsPerRegion); 604 } 605 606 size_t OtherRegionsTable::occ_sparse() const { 607 return _sparse_table.occupied(); 608 } 609 610 size_t OtherRegionsTable::mem_size() const { 611 size_t sum = 0; 612 // all PRTs are of the same size so it is sufficient to query only one of them. 613 if (_first_all_fine_prts != NULL) { 614 assert(_last_all_fine_prts != NULL && 615 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant"); 616 sum += _first_all_fine_prts->mem_size() * _n_fine_entries; 617 } 618 sum += (sizeof(PerRegionTable*) * _max_fine_entries); 619 sum += (_coarse_map.size_in_words() * HeapWordSize); 620 sum += (_sparse_table.mem_size()); 621 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above. 622 return sum; 623 } 624 625 size_t OtherRegionsTable::static_mem_size() { 626 return G1FromCardCache::static_mem_size(); 627 } 628 629 size_t OtherRegionsTable::fl_mem_size() { 630 return PerRegionTable::fl_mem_size(); 631 } 632 633 void OtherRegionsTable::clear_fcc() { 634 G1FromCardCache::clear(_hr->hrm_index()); 635 } 636 637 void OtherRegionsTable::clear() { 638 // if there are no entries, skip this step 639 if (_first_all_fine_prts != NULL) { 640 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking"); 641 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts); 642 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0])); 643 } else { 644 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking"); 645 } 646 647 _first_all_fine_prts = _last_all_fine_prts = NULL; 648 _sparse_table.clear(); 649 _coarse_map.clear(); 650 _n_fine_entries = 0; 651 _n_coarse_entries = 0; 652 653 clear_fcc(); 654 } 655 656 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const { 657 // Cast away const in this case. 658 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag); 659 return contains_reference_locked(from); 660 } 661 662 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const { 663 HeapRegion* hr = _g1h->heap_region_containing(from); 664 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index(); 665 // Is this region in the coarse map? 666 if (_coarse_map.at(hr_ind)) return true; 667 668 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask, 669 hr); 670 if (prt != NULL) { 671 return prt->contains_reference(from); 672 673 } else { 674 uintptr_t from_card = 675 (uintptr_t(from) >> CardTableModRefBS::card_shift); 676 uintptr_t hr_bot_card_index = 677 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift; 678 assert(from_card >= hr_bot_card_index, "Inv"); 679 CardIdx_t card_index = from_card - hr_bot_card_index; 680 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion, 681 "Must be in range."); 682 return _sparse_table.contains_card(hr_ind, card_index); 683 } 684 } 685 686 void 687 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 688 _sparse_table.do_cleanup_work(hrrs_cleanup_task); 689 } 690 691 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetTable* bot, 692 HeapRegion* hr) 693 : _bot(bot), 694 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never), 695 _code_roots(), _other_regions(hr, &_m), _iter_state(Unclaimed), _iter_claimed(0) { 696 reset_for_par_iteration(); 697 } 698 699 void HeapRegionRemSet::setup_remset_size() { 700 // Setup sparse and fine-grain tables sizes. 701 // table_size = base * (log(region_size / 1M) + 1) 702 const int LOG_M = 20; 703 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0); 704 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) { 705 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1); 706 } 707 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) { 708 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1); 709 } 710 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity"); 711 } 712 713 bool HeapRegionRemSet::claim_iter() { 714 if (_iter_state != Unclaimed) return false; 715 jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed); 716 return (res == Unclaimed); 717 } 718 719 void HeapRegionRemSet::set_iter_complete() { 720 _iter_state = Complete; 721 } 722 723 bool HeapRegionRemSet::iter_is_complete() { 724 return _iter_state == Complete; 725 } 726 727 #ifndef PRODUCT 728 void HeapRegionRemSet::print() { 729 HeapRegionRemSetIterator iter(this); 730 size_t card_index; 731 while (iter.has_next(card_index)) { 732 HeapWord* card_start = _bot->address_for_index(card_index); 733 tty->print_cr(" Card " PTR_FORMAT, p2i(card_start)); 734 } 735 if (iter.n_yielded() != occupied()) { 736 tty->print_cr("Yielded disagrees with occupied:"); 737 tty->print_cr(" " SIZE_FORMAT_W(6) " yielded (" SIZE_FORMAT_W(6) 738 " coarse, " SIZE_FORMAT_W(6) " fine).", 739 iter.n_yielded(), 740 iter.n_yielded_coarse(), iter.n_yielded_fine()); 741 tty->print_cr(" " SIZE_FORMAT_W(6) " occ (" SIZE_FORMAT_W(6) 742 " coarse, " SIZE_FORMAT_W(6) " fine).", 743 occupied(), occ_coarse(), occ_fine()); 744 } 745 guarantee(iter.n_yielded() == occupied(), 746 "We should have yielded all the represented cards."); 747 } 748 #endif 749 750 void HeapRegionRemSet::cleanup() { 751 SparsePRT::cleanup_all(); 752 } 753 754 void HeapRegionRemSet::clear() { 755 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); 756 clear_locked(); 757 } 758 759 void HeapRegionRemSet::clear_locked() { 760 _code_roots.clear(); 761 _other_regions.clear(); 762 assert(occupied_locked() == 0, "Should be clear."); 763 reset_for_par_iteration(); 764 } 765 766 void HeapRegionRemSet::reset_for_par_iteration() { 767 _iter_state = Unclaimed; 768 _iter_claimed = 0; 769 // It's good to check this to make sure that the two methods are in sync. 770 assert(verify_ready_for_par_iteration(), "post-condition"); 771 } 772 773 void HeapRegionRemSet::scrub(G1CardLiveData* live_data) { 774 _other_regions.scrub(live_data); 775 } 776 777 // Code roots support 778 // 779 // The code root set is protected by two separate locking schemes 780 // When at safepoint the per-hrrs lock must be held during modifications 781 // except when doing a full gc. 782 // When not at safepoint the CodeCache_lock must be held during modifications. 783 // When concurrent readers access the contains() function 784 // (during the evacuation phase) no removals are allowed. 785 786 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) { 787 assert(nm != NULL, "sanity"); 788 assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()), 789 "should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s", 790 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint())); 791 // Optimistic unlocked contains-check 792 if (!_code_roots.contains(nm)) { 793 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag); 794 add_strong_code_root_locked(nm); 795 } 796 } 797 798 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) { 799 assert(nm != NULL, "sanity"); 800 assert((CodeCache_lock->owned_by_self() || 801 (SafepointSynchronize::is_at_safepoint() && 802 (_m.owned_by_self() || Thread::current()->is_VM_thread()))), 803 "not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s", 804 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), 805 BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread())); 806 _code_roots.add(nm); 807 } 808 809 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) { 810 assert(nm != NULL, "sanity"); 811 assert_locked_or_safepoint(CodeCache_lock); 812 813 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag); 814 _code_roots.remove(nm); 815 816 // Check that there were no duplicates 817 guarantee(!_code_roots.contains(nm), "duplicate entry found"); 818 } 819 820 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const { 821 _code_roots.nmethods_do(blk); 822 } 823 824 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) { 825 _code_roots.clean(hr); 826 } 827 828 size_t HeapRegionRemSet::strong_code_roots_mem_size() { 829 return _code_roots.mem_size(); 830 } 831 832 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) : 833 _hrrs(hrrs), 834 _g1h(G1CollectedHeap::heap()), 835 _coarse_map(&hrrs->_other_regions._coarse_map), 836 _bot(hrrs->_bot), 837 _is(Sparse), 838 // Set these values so that we increment to the first region. 839 _coarse_cur_region_index(-1), 840 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1), 841 _cur_card_in_prt(HeapRegion::CardsPerRegion), 842 _fine_cur_prt(NULL), 843 _n_yielded_coarse(0), 844 _n_yielded_fine(0), 845 _n_yielded_sparse(0), 846 _sparse_iter(&hrrs->_other_regions._sparse_table) {} 847 848 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) { 849 if (_hrrs->_other_regions._n_coarse_entries == 0) return false; 850 // Go to the next card. 851 _coarse_cur_region_cur_card++; 852 // Was the last the last card in the current region? 853 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) { 854 // Yes: find the next region. This may leave _coarse_cur_region_index 855 // Set to the last index, in which case there are no more coarse 856 // regions. 857 _coarse_cur_region_index = 858 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1); 859 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) { 860 _coarse_cur_region_cur_card = 0; 861 HeapWord* r_bot = 862 _g1h->region_at((uint) _coarse_cur_region_index)->bottom(); 863 _cur_region_card_offset = _bot->index_for(r_bot); 864 } else { 865 return false; 866 } 867 } 868 // If we didn't return false above, then we can yield a card. 869 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card; 870 return true; 871 } 872 873 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) { 874 if (fine_has_next()) { 875 _cur_card_in_prt = 876 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 877 } 878 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) { 879 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for 880 // the remembered set. 881 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) { 882 return false; 883 } 884 PerRegionTable* next_prt = _fine_cur_prt->next(); 885 switch_to_prt(next_prt); 886 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 887 } 888 889 card_index = _cur_region_card_offset + _cur_card_in_prt; 890 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion, 891 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt); 892 return true; 893 } 894 895 bool HeapRegionRemSetIterator::fine_has_next() { 896 return _cur_card_in_prt != HeapRegion::CardsPerRegion; 897 } 898 899 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) { 900 assert(prt != NULL, "Cannot switch to NULL prt"); 901 _fine_cur_prt = prt; 902 903 HeapWord* r_bot = _fine_cur_prt->hr()->bottom(); 904 _cur_region_card_offset = _bot->index_for(r_bot); 905 906 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1. 907 // To avoid special-casing this start case, and not miss the first bitmap 908 // entry, initialize _cur_region_cur_card with -1 instead of 0. 909 _cur_card_in_prt = (size_t)-1; 910 } 911 912 bool HeapRegionRemSetIterator::has_next(size_t& card_index) { 913 switch (_is) { 914 case Sparse: { 915 if (_sparse_iter.has_next(card_index)) { 916 _n_yielded_sparse++; 917 return true; 918 } 919 // Otherwise, deliberate fall-through 920 _is = Fine; 921 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts; 922 if (initial_fine_prt != NULL) { 923 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts); 924 } 925 } 926 case Fine: 927 if (fine_has_next(card_index)) { 928 _n_yielded_fine++; 929 return true; 930 } 931 // Otherwise, deliberate fall-through 932 _is = Coarse; 933 case Coarse: 934 if (coarse_has_next(card_index)) { 935 _n_yielded_coarse++; 936 return true; 937 } 938 // Otherwise... 939 break; 940 } 941 assert(ParallelGCThreads > 1 || 942 n_yielded() == _hrrs->occupied(), 943 "Should have yielded all the cards in the rem set " 944 "(in the non-par case)."); 945 return false; 946 } 947 948 void HeapRegionRemSet::reset_for_cleanup_tasks() { 949 SparsePRT::reset_for_cleanup_tasks(); 950 } 951 952 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 953 _other_regions.do_cleanup_work(hrrs_cleanup_task); 954 } 955 956 void 957 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) { 958 SparsePRT::finish_cleanup_task(hrrs_cleanup_task); 959 } 960 961 #ifndef PRODUCT 962 void HeapRegionRemSet::test() { 963 os::sleep(Thread::current(), (jlong)5000, false); 964 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 965 966 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same 967 // hash bucket. 968 HeapRegion* hr0 = g1h->region_at(0); 969 HeapRegion* hr1 = g1h->region_at(1); 970 HeapRegion* hr2 = g1h->region_at(5); 971 HeapRegion* hr3 = g1h->region_at(6); 972 HeapRegion* hr4 = g1h->region_at(7); 973 HeapRegion* hr5 = g1h->region_at(8); 974 975 HeapWord* hr1_start = hr1->bottom(); 976 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2; 977 HeapWord* hr1_last = hr1->end() - 1; 978 979 HeapWord* hr2_start = hr2->bottom(); 980 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2; 981 HeapWord* hr2_last = hr2->end() - 1; 982 983 HeapWord* hr3_start = hr3->bottom(); 984 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2; 985 HeapWord* hr3_last = hr3->end() - 1; 986 987 HeapRegionRemSet* hrrs = hr0->rem_set(); 988 989 // Make three references from region 0x101... 990 hrrs->add_reference((OopOrNarrowOopStar)hr1_start); 991 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid); 992 hrrs->add_reference((OopOrNarrowOopStar)hr1_last); 993 994 hrrs->add_reference((OopOrNarrowOopStar)hr2_start); 995 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid); 996 hrrs->add_reference((OopOrNarrowOopStar)hr2_last); 997 998 hrrs->add_reference((OopOrNarrowOopStar)hr3_start); 999 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid); 1000 hrrs->add_reference((OopOrNarrowOopStar)hr3_last); 1001 1002 // Now cause a coarsening. 1003 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom()); 1004 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom()); 1005 1006 // Now, does iteration yield these three? 1007 HeapRegionRemSetIterator iter(hrrs); 1008 size_t sum = 0; 1009 size_t card_index; 1010 while (iter.has_next(card_index)) { 1011 HeapWord* card_start = 1012 G1CollectedHeap::heap()->bot()->address_for_index(card_index); 1013 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start)); 1014 sum++; 1015 } 1016 guarantee(sum == 11 - 3 + 2048, "Failure"); 1017 guarantee(sum == hrrs->occupied(), "Failure"); 1018 } 1019 #endif