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/heapRegionManager.inline.hpp" 30 #include "gc/g1/heapRegionRemSet.hpp" 31 #include "gc/shared/space.inline.hpp" 32 #include "memory/allocation.hpp" 33 #include "memory/padded.inline.hpp" 34 #include "oops/oop.inline.hpp" 35 #include "runtime/atomic.inline.hpp" 36 #include "utilities/bitMap.inline.hpp" 37 #include "utilities/globalDefinitions.hpp" 38 #include "utilities/growableArray.hpp" 39 40 class PerRegionTable: public CHeapObj<mtGC> { 41 friend class OtherRegionsTable; 42 friend class HeapRegionRemSetIterator; 43 44 HeapRegion* _hr; 45 BitMap _bm; 46 jint _occupied; 47 48 // next pointer for free/allocated 'all' list 49 PerRegionTable* _next; 50 51 // prev pointer for the allocated 'all' list 52 PerRegionTable* _prev; 53 54 // next pointer in collision list 55 PerRegionTable * _collision_list_next; 56 57 // Global free list of PRTs 58 static PerRegionTable* _free_list; 59 60 protected: 61 // We need access in order to union things into the base table. 62 BitMap* bm() { return &_bm; } 63 64 void recount_occupied() { 65 _occupied = (jint) bm()->count_one_bits(); 66 } 67 68 PerRegionTable(HeapRegion* hr) : 69 _hr(hr), 70 _occupied(0), 71 _bm(HeapRegion::CardsPerRegion, false /* in-resource-area */), 72 _collision_list_next(NULL), _next(NULL), _prev(NULL) 73 {} 74 75 void add_card_work(CardIdx_t from_card, bool par) { 76 if (!_bm.at(from_card)) { 77 if (par) { 78 if (_bm.par_at_put(from_card, 1)) { 79 Atomic::inc(&_occupied); 80 } 81 } else { 82 _bm.at_put(from_card, 1); 83 _occupied++; 84 } 85 } 86 } 87 88 void add_reference_work(OopOrNarrowOopStar from, bool par) { 89 // Must make this robust in case "from" is not in "_hr", because of 90 // concurrency. 91 92 HeapRegion* loc_hr = hr(); 93 // If the test below fails, then this table was reused concurrently 94 // with this operation. This is OK, since the old table was coarsened, 95 // and adding a bit to the new table is never incorrect. 96 // If the table used to belong to a continues humongous region and is 97 // now reused for the corresponding start humongous region, we need to 98 // make sure that we detect this. Thus, we call is_in_reserved_raw() 99 // instead of just is_in_reserved() here. 100 if (loc_hr->is_in_reserved(from)) { 101 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom()); 102 CardIdx_t from_card = (CardIdx_t) 103 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize); 104 105 assert(0 <= from_card && (size_t)from_card < HeapRegion::CardsPerRegion, 106 "Must be in range."); 107 add_card_work(from_card, par); 108 } 109 } 110 111 public: 112 113 HeapRegion* hr() const { 114 return (HeapRegion*) OrderAccess::load_ptr_acquire(&_hr); 115 } 116 117 jint occupied() const { 118 // Overkill, but if we ever need it... 119 // guarantee(_occupied == _bm.count_one_bits(), "Check"); 120 return _occupied; 121 } 122 123 void init(HeapRegion* hr, bool clear_links_to_all_list) { 124 if (clear_links_to_all_list) { 125 set_next(NULL); 126 set_prev(NULL); 127 } 128 _collision_list_next = NULL; 129 _occupied = 0; 130 _bm.clear(); 131 // Make sure that the bitmap clearing above has been finished before publishing 132 // this PRT to concurrent threads. 133 OrderAccess::release_store_ptr(&_hr, hr); 134 } 135 136 void add_reference(OopOrNarrowOopStar from) { 137 add_reference_work(from, /*parallel*/ true); 138 } 139 140 void seq_add_reference(OopOrNarrowOopStar from) { 141 add_reference_work(from, /*parallel*/ false); 142 } 143 144 void scrub(CardTableModRefBS* ctbs, BitMap* card_bm) { 145 HeapWord* hr_bot = hr()->bottom(); 146 size_t hr_first_card_index = ctbs->index_for(hr_bot); 147 bm()->set_intersection_at_offset(*card_bm, hr_first_card_index); 148 recount_occupied(); 149 } 150 151 void add_card(CardIdx_t from_card_index) { 152 add_card_work(from_card_index, /*parallel*/ true); 153 } 154 155 void seq_add_card(CardIdx_t from_card_index) { 156 add_card_work(from_card_index, /*parallel*/ false); 157 } 158 159 // (Destructively) union the bitmap of the current table into the given 160 // bitmap (which is assumed to be of the same size.) 161 void union_bitmap_into(BitMap* bm) { 162 bm->set_union(_bm); 163 } 164 165 // Mem size in bytes. 166 size_t mem_size() const { 167 return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize; 168 } 169 170 // Requires "from" to be in "hr()". 171 bool contains_reference(OopOrNarrowOopStar from) const { 172 assert(hr()->is_in_reserved(from), "Precondition."); 173 size_t card_ind = pointer_delta(from, hr()->bottom(), 174 CardTableModRefBS::card_size); 175 return _bm.at(card_ind); 176 } 177 178 // Bulk-free the PRTs from prt to last, assumes that they are 179 // linked together using their _next field. 180 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) { 181 while (true) { 182 PerRegionTable* fl = _free_list; 183 last->set_next(fl); 184 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl); 185 if (res == fl) { 186 return; 187 } 188 } 189 ShouldNotReachHere(); 190 } 191 192 static void free(PerRegionTable* prt) { 193 bulk_free(prt, prt); 194 } 195 196 // Returns an initialized PerRegionTable instance. 197 static PerRegionTable* alloc(HeapRegion* hr) { 198 PerRegionTable* fl = _free_list; 199 while (fl != NULL) { 200 PerRegionTable* nxt = fl->next(); 201 PerRegionTable* res = 202 (PerRegionTable*) 203 Atomic::cmpxchg_ptr(nxt, &_free_list, fl); 204 if (res == fl) { 205 fl->init(hr, true); 206 return fl; 207 } else { 208 fl = _free_list; 209 } 210 } 211 assert(fl == NULL, "Loop condition."); 212 return new PerRegionTable(hr); 213 } 214 215 PerRegionTable* next() const { return _next; } 216 void set_next(PerRegionTable* next) { _next = next; } 217 PerRegionTable* prev() const { return _prev; } 218 void set_prev(PerRegionTable* prev) { _prev = prev; } 219 220 // Accessor and Modification routines for the pointer for the 221 // singly linked collision list that links the PRTs within the 222 // OtherRegionsTable::_fine_grain_regions hash table. 223 // 224 // It might be useful to also make the collision list doubly linked 225 // to avoid iteration over the collisions list during scrubbing/deletion. 226 // OTOH there might not be many collisions. 227 228 PerRegionTable* collision_list_next() const { 229 return _collision_list_next; 230 } 231 232 void set_collision_list_next(PerRegionTable* next) { 233 _collision_list_next = next; 234 } 235 236 PerRegionTable** collision_list_next_addr() { 237 return &_collision_list_next; 238 } 239 240 static size_t fl_mem_size() { 241 PerRegionTable* cur = _free_list; 242 size_t res = 0; 243 while (cur != NULL) { 244 res += cur->mem_size(); 245 cur = cur->next(); 246 } 247 return res; 248 } 249 250 static void test_fl_mem_size(); 251 }; 252 253 PerRegionTable* PerRegionTable::_free_list = NULL; 254 255 size_t OtherRegionsTable::_max_fine_entries = 0; 256 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0; 257 size_t OtherRegionsTable::_fine_eviction_stride = 0; 258 size_t OtherRegionsTable::_fine_eviction_sample_size = 0; 259 260 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) : 261 _g1h(G1CollectedHeap::heap()), 262 _hr(hr), _m(m), 263 _coarse_map(G1CollectedHeap::heap()->max_regions(), 264 false /* in-resource-area */), 265 _fine_grain_regions(NULL), 266 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL), 267 _n_fine_entries(0), _n_coarse_entries(0), 268 _fine_eviction_start(0), 269 _sparse_table(hr) 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 _n_coarse_entries++; 509 } 510 511 // Unsplice. 512 *max_prev = max->collision_list_next(); 513 Atomic::inc(&_n_coarsenings); 514 _n_fine_entries--; 515 return max; 516 } 517 518 void OtherRegionsTable::scrub(CardTableModRefBS* ctbs, 519 BitMap* region_bm, BitMap* card_bm) { 520 // First eliminated garbage regions from the coarse map. 521 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index()); 522 523 assert(_coarse_map.size() == region_bm->size(), "Precondition"); 524 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries); 525 _coarse_map.set_intersection(*region_bm); 526 _n_coarse_entries = _coarse_map.count_one_bits(); 527 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries); 528 529 // Now do the fine-grained maps. 530 for (size_t i = 0; i < _max_fine_entries; i++) { 531 PerRegionTable* cur = _fine_grain_regions[i]; 532 PerRegionTable** prev = &_fine_grain_regions[i]; 533 while (cur != NULL) { 534 PerRegionTable* nxt = cur->collision_list_next(); 535 // If the entire region is dead, eliminate. 536 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index()); 537 if (!region_bm->at((size_t) cur->hr()->hrm_index())) { 538 *prev = nxt; 539 cur->set_collision_list_next(NULL); 540 _n_fine_entries--; 541 log_develop_trace(gc, remset, scrub)(" deleted via region map."); 542 unlink_from_all(cur); 543 PerRegionTable::free(cur); 544 } else { 545 // Do fine-grain elimination. 546 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied()); 547 cur->scrub(ctbs, card_bm); 548 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied()); 549 // Did that empty the table completely? 550 if (cur->occupied() == 0) { 551 *prev = nxt; 552 cur->set_collision_list_next(NULL); 553 _n_fine_entries--; 554 unlink_from_all(cur); 555 PerRegionTable::free(cur); 556 } else { 557 prev = cur->collision_list_next_addr(); 558 } 559 } 560 cur = nxt; 561 } 562 } 563 // Since we may have deleted a from_card_cache entry from the RS, clear 564 // the FCC. 565 clear_fcc(); 566 } 567 568 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const { 569 if (limit <= (size_t)G1RSetSparseRegionEntries) { 570 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit; 571 } else { 572 // Current uses of this method may only use values less than G1RSetSparseRegionEntries 573 // for the limit. The solution, comparing against occupied() would be too slow 574 // at this time. 575 Unimplemented(); 576 return false; 577 } 578 } 579 580 bool OtherRegionsTable::is_empty() const { 581 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL; 582 } 583 584 size_t OtherRegionsTable::occupied() const { 585 size_t sum = occ_fine(); 586 sum += occ_sparse(); 587 sum += occ_coarse(); 588 return sum; 589 } 590 591 size_t OtherRegionsTable::occ_fine() const { 592 size_t sum = 0; 593 594 size_t num = 0; 595 PerRegionTable * cur = _first_all_fine_prts; 596 while (cur != NULL) { 597 sum += cur->occupied(); 598 cur = cur->next(); 599 num++; 600 } 601 guarantee(num == _n_fine_entries, "just checking"); 602 return sum; 603 } 604 605 size_t OtherRegionsTable::occ_coarse() const { 606 return (_n_coarse_entries * HeapRegion::CardsPerRegion); 607 } 608 609 size_t OtherRegionsTable::occ_sparse() const { 610 return _sparse_table.occupied(); 611 } 612 613 size_t OtherRegionsTable::mem_size() const { 614 size_t sum = 0; 615 // all PRTs are of the same size so it is sufficient to query only one of them. 616 if (_first_all_fine_prts != NULL) { 617 assert(_last_all_fine_prts != NULL && 618 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant"); 619 sum += _first_all_fine_prts->mem_size() * _n_fine_entries; 620 } 621 sum += (sizeof(PerRegionTable*) * _max_fine_entries); 622 sum += (_coarse_map.size_in_words() * HeapWordSize); 623 sum += (_sparse_table.mem_size()); 624 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above. 625 return sum; 626 } 627 628 size_t OtherRegionsTable::static_mem_size() { 629 return G1FromCardCache::static_mem_size(); 630 } 631 632 size_t OtherRegionsTable::fl_mem_size() { 633 return PerRegionTable::fl_mem_size(); 634 } 635 636 void OtherRegionsTable::clear_fcc() { 637 G1FromCardCache::clear(_hr->hrm_index()); 638 } 639 640 void OtherRegionsTable::clear() { 641 // if there are no entries, skip this step 642 if (_first_all_fine_prts != NULL) { 643 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking"); 644 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts); 645 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0])); 646 } else { 647 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking"); 648 } 649 650 _first_all_fine_prts = _last_all_fine_prts = NULL; 651 _sparse_table.clear(); 652 _coarse_map.clear(); 653 _n_fine_entries = 0; 654 _n_coarse_entries = 0; 655 656 clear_fcc(); 657 } 658 659 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const { 660 // Cast away const in this case. 661 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag); 662 return contains_reference_locked(from); 663 } 664 665 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const { 666 HeapRegion* hr = _g1h->heap_region_containing(from); 667 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index(); 668 // Is this region in the coarse map? 669 if (_coarse_map.at(hr_ind)) return true; 670 671 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask, 672 hr); 673 if (prt != NULL) { 674 return prt->contains_reference(from); 675 676 } else { 677 uintptr_t from_card = 678 (uintptr_t(from) >> CardTableModRefBS::card_shift); 679 uintptr_t hr_bot_card_index = 680 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift; 681 assert(from_card >= hr_bot_card_index, "Inv"); 682 CardIdx_t card_index = from_card - hr_bot_card_index; 683 assert(0 <= card_index && (size_t)card_index < HeapRegion::CardsPerRegion, 684 "Must be in range."); 685 return _sparse_table.contains_card(hr_ind, card_index); 686 } 687 } 688 689 void 690 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 691 _sparse_table.do_cleanup_work(hrrs_cleanup_task); 692 } 693 694 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetTable* bot, 695 HeapRegion* hr) 696 : _bot(bot), 697 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never), 698 _code_roots(), _other_regions(hr, &_m), _iter_state(Unclaimed), _iter_claimed(0) { 699 reset_for_par_iteration(); 700 } 701 702 void HeapRegionRemSet::setup_remset_size() { 703 // Setup sparse and fine-grain tables sizes. 704 // table_size = base * (log(region_size / 1M) + 1) 705 const int LOG_M = 20; 706 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0); 707 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) { 708 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1); 709 } 710 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) { 711 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1); 712 } 713 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity"); 714 } 715 716 bool HeapRegionRemSet::claim_iter() { 717 if (_iter_state != Unclaimed) return false; 718 jint res = Atomic::cmpxchg(Claimed, (jint*)(&_iter_state), Unclaimed); 719 return (res == Unclaimed); 720 } 721 722 void HeapRegionRemSet::set_iter_complete() { 723 _iter_state = Complete; 724 } 725 726 bool HeapRegionRemSet::iter_is_complete() { 727 return _iter_state == Complete; 728 } 729 730 #ifndef PRODUCT 731 void HeapRegionRemSet::print() { 732 HeapRegionRemSetIterator iter(this); 733 size_t card_index; 734 while (iter.has_next(card_index)) { 735 HeapWord* card_start = _bot->address_for_index(card_index); 736 tty->print_cr(" Card " PTR_FORMAT, p2i(card_start)); 737 } 738 if (iter.n_yielded() != occupied()) { 739 tty->print_cr("Yielded disagrees with occupied:"); 740 tty->print_cr(" " SIZE_FORMAT_W(6) " yielded (" SIZE_FORMAT_W(6) 741 " coarse, " SIZE_FORMAT_W(6) " fine).", 742 iter.n_yielded(), 743 iter.n_yielded_coarse(), iter.n_yielded_fine()); 744 tty->print_cr(" " SIZE_FORMAT_W(6) " occ (" SIZE_FORMAT_W(6) 745 " coarse, " SIZE_FORMAT_W(6) " fine).", 746 occupied(), occ_coarse(), occ_fine()); 747 } 748 guarantee(iter.n_yielded() == occupied(), 749 "We should have yielded all the represented cards."); 750 } 751 #endif 752 753 void HeapRegionRemSet::cleanup() { 754 SparsePRT::cleanup_all(); 755 } 756 757 void HeapRegionRemSet::clear() { 758 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); 759 clear_locked(); 760 } 761 762 void HeapRegionRemSet::clear_locked() { 763 _code_roots.clear(); 764 _other_regions.clear(); 765 assert(occupied_locked() == 0, "Should be clear."); 766 reset_for_par_iteration(); 767 } 768 769 void HeapRegionRemSet::reset_for_par_iteration() { 770 _iter_state = Unclaimed; 771 _iter_claimed = 0; 772 // It's good to check this to make sure that the two methods are in sync. 773 assert(verify_ready_for_par_iteration(), "post-condition"); 774 } 775 776 void HeapRegionRemSet::scrub(CardTableModRefBS* ctbs, 777 BitMap* region_bm, BitMap* card_bm) { 778 _other_regions.scrub(ctbs, region_bm, card_bm); 779 } 780 781 // Code roots support 782 // 783 // The code root set is protected by two separate locking schemes 784 // When at safepoint the per-hrrs lock must be held during modifications 785 // except when doing a full gc. 786 // When not at safepoint the CodeCache_lock must be held during modifications. 787 // When concurrent readers access the contains() function 788 // (during the evacuation phase) no removals are allowed. 789 790 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) { 791 assert(nm != NULL, "sanity"); 792 // Optimistic unlocked contains-check 793 if (!_code_roots.contains(nm)) { 794 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag); 795 add_strong_code_root_locked(nm); 796 } 797 } 798 799 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) { 800 assert(nm != NULL, "sanity"); 801 _code_roots.add(nm); 802 } 803 804 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) { 805 assert(nm != NULL, "sanity"); 806 assert_locked_or_safepoint(CodeCache_lock); 807 808 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag); 809 _code_roots.remove(nm); 810 811 // Check that there were no duplicates 812 guarantee(!_code_roots.contains(nm), "duplicate entry found"); 813 } 814 815 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const { 816 _code_roots.nmethods_do(blk); 817 } 818 819 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) { 820 _code_roots.clean(hr); 821 } 822 823 size_t HeapRegionRemSet::strong_code_roots_mem_size() { 824 return _code_roots.mem_size(); 825 } 826 827 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) : 828 _hrrs(hrrs), 829 _g1h(G1CollectedHeap::heap()), 830 _coarse_map(&hrrs->_other_regions._coarse_map), 831 _bot(hrrs->_bot), 832 _is(Sparse), 833 // Set these values so that we increment to the first region. 834 _coarse_cur_region_index(-1), 835 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1), 836 _cur_card_in_prt(HeapRegion::CardsPerRegion), 837 _fine_cur_prt(NULL), 838 _n_yielded_coarse(0), 839 _n_yielded_fine(0), 840 _n_yielded_sparse(0), 841 _sparse_iter(&hrrs->_other_regions._sparse_table) {} 842 843 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) { 844 if (_hrrs->_other_regions._n_coarse_entries == 0) return false; 845 // Go to the next card. 846 _coarse_cur_region_cur_card++; 847 // Was the last the last card in the current region? 848 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) { 849 // Yes: find the next region. This may leave _coarse_cur_region_index 850 // Set to the last index, in which case there are no more coarse 851 // regions. 852 _coarse_cur_region_index = 853 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1); 854 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) { 855 _coarse_cur_region_cur_card = 0; 856 HeapWord* r_bot = 857 _g1h->region_at((uint) _coarse_cur_region_index)->bottom(); 858 _cur_region_card_offset = _bot->index_for(r_bot); 859 } else { 860 return false; 861 } 862 } 863 // If we didn't return false above, then we can yield a card. 864 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card; 865 return true; 866 } 867 868 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) { 869 if (fine_has_next()) { 870 _cur_card_in_prt = 871 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 872 } 873 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) { 874 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for 875 // the remembered set. 876 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) { 877 return false; 878 } 879 PerRegionTable* next_prt = _fine_cur_prt->next(); 880 switch_to_prt(next_prt); 881 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 882 } 883 884 card_index = _cur_region_card_offset + _cur_card_in_prt; 885 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion, 886 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt); 887 return true; 888 } 889 890 bool HeapRegionRemSetIterator::fine_has_next() { 891 return _cur_card_in_prt != HeapRegion::CardsPerRegion; 892 } 893 894 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) { 895 assert(prt != NULL, "Cannot switch to NULL prt"); 896 _fine_cur_prt = prt; 897 898 HeapWord* r_bot = _fine_cur_prt->hr()->bottom(); 899 _cur_region_card_offset = _bot->index_for(r_bot); 900 901 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1. 902 // To avoid special-casing this start case, and not miss the first bitmap 903 // entry, initialize _cur_region_cur_card with -1 instead of 0. 904 _cur_card_in_prt = (size_t)-1; 905 } 906 907 bool HeapRegionRemSetIterator::has_next(size_t& card_index) { 908 switch (_is) { 909 case Sparse: { 910 if (_sparse_iter.has_next(card_index)) { 911 _n_yielded_sparse++; 912 return true; 913 } 914 // Otherwise, deliberate fall-through 915 _is = Fine; 916 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts; 917 if (initial_fine_prt != NULL) { 918 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts); 919 } 920 } 921 case Fine: 922 if (fine_has_next(card_index)) { 923 _n_yielded_fine++; 924 return true; 925 } 926 // Otherwise, deliberate fall-through 927 _is = Coarse; 928 case Coarse: 929 if (coarse_has_next(card_index)) { 930 _n_yielded_coarse++; 931 return true; 932 } 933 // Otherwise... 934 break; 935 } 936 assert(ParallelGCThreads > 1 || 937 n_yielded() == _hrrs->occupied(), 938 "Should have yielded all the cards in the rem set " 939 "(in the non-par case)."); 940 return false; 941 } 942 943 void HeapRegionRemSet::reset_for_cleanup_tasks() { 944 SparsePRT::reset_for_cleanup_tasks(); 945 } 946 947 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 948 _other_regions.do_cleanup_work(hrrs_cleanup_task); 949 } 950 951 void 952 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) { 953 SparsePRT::finish_cleanup_task(hrrs_cleanup_task); 954 } 955 956 #ifndef PRODUCT 957 void HeapRegionRemSet::test() { 958 os::sleep(Thread::current(), (jlong)5000, false); 959 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 960 961 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same 962 // hash bucket. 963 HeapRegion* hr0 = g1h->region_at(0); 964 HeapRegion* hr1 = g1h->region_at(1); 965 HeapRegion* hr2 = g1h->region_at(5); 966 HeapRegion* hr3 = g1h->region_at(6); 967 HeapRegion* hr4 = g1h->region_at(7); 968 HeapRegion* hr5 = g1h->region_at(8); 969 970 HeapWord* hr1_start = hr1->bottom(); 971 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2; 972 HeapWord* hr1_last = hr1->end() - 1; 973 974 HeapWord* hr2_start = hr2->bottom(); 975 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2; 976 HeapWord* hr2_last = hr2->end() - 1; 977 978 HeapWord* hr3_start = hr3->bottom(); 979 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2; 980 HeapWord* hr3_last = hr3->end() - 1; 981 982 HeapRegionRemSet* hrrs = hr0->rem_set(); 983 984 // Make three references from region 0x101... 985 hrrs->add_reference((OopOrNarrowOopStar)hr1_start); 986 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid); 987 hrrs->add_reference((OopOrNarrowOopStar)hr1_last); 988 989 hrrs->add_reference((OopOrNarrowOopStar)hr2_start); 990 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid); 991 hrrs->add_reference((OopOrNarrowOopStar)hr2_last); 992 993 hrrs->add_reference((OopOrNarrowOopStar)hr3_start); 994 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid); 995 hrrs->add_reference((OopOrNarrowOopStar)hr3_last); 996 997 // Now cause a coarsening. 998 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom()); 999 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom()); 1000 1001 // Now, does iteration yield these three? 1002 HeapRegionRemSetIterator iter(hrrs); 1003 size_t sum = 0; 1004 size_t card_index; 1005 while (iter.has_next(card_index)) { 1006 HeapWord* card_start = 1007 G1CollectedHeap::heap()->bot()->address_for_index(card_index); 1008 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start)); 1009 sum++; 1010 } 1011 guarantee(sum == 11 - 3 + 2048, "Failure"); 1012 guarantee(sum == hrrs->occupied(), "Failure"); 1013 } 1014 #endif