1 /* 2 * Copyright (c) 2001, 2017, 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.hpp" 37 #include "utilities/bitMap.inline.hpp" 38 #include "utilities/debug.hpp" 39 #include "utilities/formatBuffer.hpp" 40 #include "utilities/globalDefinitions.hpp" 41 #include "utilities/growableArray.hpp" 42 43 class PerRegionTable: public CHeapObj<mtGC> { 44 friend class OtherRegionsTable; 45 friend class HeapRegionRemSetIterator; 46 47 HeapRegion* _hr; 48 CHeapBitMap _bm; 49 jint _occupied; 50 51 // next pointer for free/allocated 'all' list 52 PerRegionTable* _next; 53 54 // prev pointer for the allocated 'all' list 55 PerRegionTable* _prev; 56 57 // next pointer in collision list 58 PerRegionTable * _collision_list_next; 59 60 // Global free list of PRTs 61 static PerRegionTable* volatile _free_list; 62 63 protected: 64 // We need access in order to union things into the base table. 65 BitMap* bm() { return &_bm; } 66 67 void recount_occupied() { 68 _occupied = (jint) bm()->count_one_bits(); 69 } 70 71 PerRegionTable(HeapRegion* hr) : 72 _hr(hr), 73 _occupied(0), 74 _bm(HeapRegion::CardsPerRegion, mtGC), 75 _collision_list_next(NULL), _next(NULL), _prev(NULL) 76 {} 77 78 void add_card_work(CardIdx_t from_card, bool par) { 79 if (!_bm.at(from_card)) { 80 if (par) { 81 if (_bm.par_at_put(from_card, 1)) { 82 Atomic::inc(&_occupied); 83 } 84 } else { 85 _bm.at_put(from_card, 1); 86 _occupied++; 87 } 88 } 89 } 90 91 void add_reference_work(OopOrNarrowOopStar from, bool par) { 92 // Must make this robust in case "from" is not in "_hr", because of 93 // concurrency. 94 95 HeapRegion* loc_hr = hr(); 96 // If the test below fails, then this table was reused concurrently 97 // with this operation. This is OK, since the old table was coarsened, 98 // and adding a bit to the new table is never incorrect. 99 // If the table used to belong to a continues humongous region and is 100 // now reused for the corresponding start humongous region, we need to 101 // make sure that we detect this. Thus, we call is_in_reserved_raw() 102 // instead of just is_in_reserved() here. 103 if (loc_hr->is_in_reserved(from)) { 104 size_t hw_offset = pointer_delta((HeapWord*)from, loc_hr->bottom()); 105 CardIdx_t from_card = (CardIdx_t) 106 hw_offset >> (CardTableModRefBS::card_shift - LogHeapWordSize); 107 108 assert((size_t)from_card < HeapRegion::CardsPerRegion, 109 "Must be in range."); 110 add_card_work(from_card, par); 111 } 112 } 113 114 public: 115 116 HeapRegion* hr() const { return OrderAccess::load_acquire(&_hr); } 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(&_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 = Atomic::cmpxchg(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 = Atomic::cmpxchg(nxt, &_free_list, fl); 201 if (res == fl) { 202 fl->init(hr, true); 203 return fl; 204 } else { 205 fl = _free_list; 206 } 207 } 208 assert(fl == NULL, "Loop condition."); 209 return new PerRegionTable(hr); 210 } 211 212 PerRegionTable* next() const { return _next; } 213 void set_next(PerRegionTable* next) { _next = next; } 214 PerRegionTable* prev() const { return _prev; } 215 void set_prev(PerRegionTable* prev) { _prev = prev; } 216 217 // Accessor and Modification routines for the pointer for the 218 // singly linked collision list that links the PRTs within the 219 // OtherRegionsTable::_fine_grain_regions hash table. 220 // 221 // It might be useful to also make the collision list doubly linked 222 // to avoid iteration over the collisions list during scrubbing/deletion. 223 // OTOH there might not be many collisions. 224 225 PerRegionTable* collision_list_next() const { 226 return _collision_list_next; 227 } 228 229 void set_collision_list_next(PerRegionTable* next) { 230 _collision_list_next = next; 231 } 232 233 PerRegionTable** collision_list_next_addr() { 234 return &_collision_list_next; 235 } 236 237 static size_t fl_mem_size() { 238 PerRegionTable* cur = _free_list; 239 size_t res = 0; 240 while (cur != NULL) { 241 res += cur->mem_size(); 242 cur = cur->next(); 243 } 244 return res; 245 } 246 247 static void test_fl_mem_size(); 248 }; 249 250 PerRegionTable* volatile PerRegionTable::_free_list = NULL; 251 252 size_t OtherRegionsTable::_max_fine_entries = 0; 253 size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0; 254 size_t OtherRegionsTable::_fine_eviction_stride = 0; 255 size_t OtherRegionsTable::_fine_eviction_sample_size = 0; 256 257 OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) : 258 _g1h(G1CollectedHeap::heap()), 259 _hr(hr), _m(m), 260 _coarse_map(G1CollectedHeap::heap()->max_regions(), mtGC), 261 _fine_grain_regions(NULL), 262 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL), 263 _n_fine_entries(0), _n_coarse_entries(0), 264 _fine_eviction_start(0), 265 _sparse_table(hr) 266 { 267 typedef PerRegionTable* PerRegionTablePtr; 268 269 if (_max_fine_entries == 0) { 270 assert(_mod_max_fine_entries_mask == 0, "Both or none."); 271 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries); 272 _max_fine_entries = (size_t)1 << max_entries_log; 273 _mod_max_fine_entries_mask = _max_fine_entries - 1; 274 275 assert(_fine_eviction_sample_size == 0 276 && _fine_eviction_stride == 0, "All init at same time."); 277 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log); 278 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size; 279 } 280 281 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries, 282 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 283 284 if (_fine_grain_regions == NULL) { 285 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR, 286 "Failed to allocate _fine_grain_entries."); 287 } 288 289 for (size_t i = 0; i < _max_fine_entries; i++) { 290 _fine_grain_regions[i] = NULL; 291 } 292 } 293 294 void OtherRegionsTable::link_to_all(PerRegionTable* prt) { 295 // We always append to the beginning of the list for convenience; 296 // the order of entries in this list does not matter. 297 if (_first_all_fine_prts != NULL) { 298 assert(_first_all_fine_prts->prev() == NULL, "invariant"); 299 _first_all_fine_prts->set_prev(prt); 300 prt->set_next(_first_all_fine_prts); 301 } else { 302 // this is the first element we insert. Adjust the "last" pointer 303 _last_all_fine_prts = prt; 304 assert(prt->next() == NULL, "just checking"); 305 } 306 // the new element is always the first element without a predecessor 307 prt->set_prev(NULL); 308 _first_all_fine_prts = prt; 309 310 assert(prt->prev() == NULL, "just checking"); 311 assert(_first_all_fine_prts == prt, "just checking"); 312 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 313 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 314 "just checking"); 315 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 316 "just checking"); 317 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 318 "just checking"); 319 } 320 321 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) { 322 if (prt->prev() != NULL) { 323 assert(_first_all_fine_prts != prt, "just checking"); 324 prt->prev()->set_next(prt->next()); 325 // removing the last element in the list? 326 if (_last_all_fine_prts == prt) { 327 _last_all_fine_prts = prt->prev(); 328 } 329 } else { 330 assert(_first_all_fine_prts == prt, "just checking"); 331 _first_all_fine_prts = prt->next(); 332 // list is empty now? 333 if (_first_all_fine_prts == NULL) { 334 _last_all_fine_prts = NULL; 335 } 336 } 337 338 if (prt->next() != NULL) { 339 prt->next()->set_prev(prt->prev()); 340 } 341 342 prt->set_next(NULL); 343 prt->set_prev(NULL); 344 345 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 346 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 347 "just checking"); 348 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 349 "just checking"); 350 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 351 "just checking"); 352 } 353 354 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, uint tid) { 355 uint cur_hrm_ind = _hr->hrm_index(); 356 357 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift); 358 359 if (G1FromCardCache::contains_or_replace(tid, cur_hrm_ind, from_card)) { 360 assert(contains_reference(from), "We just found " PTR_FORMAT " in the FromCardCache", p2i(from)); 361 return; 362 } 363 364 // Note that this may be a continued H region. 365 HeapRegion* from_hr = _g1h->heap_region_containing(from); 366 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index(); 367 368 // If the region is already coarsened, return. 369 if (_coarse_map.at(from_hrm_ind)) { 370 assert(contains_reference(from), "We just found " PTR_FORMAT " in the Coarse table", p2i(from)); 371 return; 372 } 373 374 // Otherwise find a per-region table to add it to. 375 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask; 376 PerRegionTable* prt = find_region_table(ind, from_hr); 377 if (prt == NULL) { 378 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag); 379 // Confirm that it's really not there... 380 prt = find_region_table(ind, from_hr); 381 if (prt == NULL) { 382 383 uintptr_t from_hr_bot_card_index = 384 uintptr_t(from_hr->bottom()) 385 >> CardTableModRefBS::card_shift; 386 CardIdx_t card_index = from_card - from_hr_bot_card_index; 387 assert((size_t)card_index < HeapRegion::CardsPerRegion, 388 "Must be in range."); 389 if (G1HRRSUseSparseTable && 390 _sparse_table.add_card(from_hrm_ind, card_index)) { 391 assert(contains_reference_locked(from), "We just added " PTR_FORMAT " to the Sparse table", p2i(from)); 392 return; 393 } 394 395 if (_n_fine_entries == _max_fine_entries) { 396 prt = delete_region_table(); 397 // There is no need to clear the links to the 'all' list here: 398 // prt will be reused immediately, i.e. remain in the 'all' list. 399 prt->init(from_hr, false /* clear_links_to_all_list */); 400 } else { 401 prt = PerRegionTable::alloc(from_hr); 402 link_to_all(prt); 403 } 404 405 PerRegionTable* first_prt = _fine_grain_regions[ind]; 406 prt->set_collision_list_next(first_prt); 407 // The assignment into _fine_grain_regions allows the prt to 408 // start being used concurrently. In addition to 409 // collision_list_next which must be visible (else concurrent 410 // parsing of the list, if any, may fail to see other entries), 411 // the content of the prt must be visible (else for instance 412 // some mark bits may not yet seem cleared or a 'later' update 413 // performed by a concurrent thread could be undone when the 414 // zeroing becomes visible). This requires store ordering. 415 OrderAccess::release_store(&_fine_grain_regions[ind], prt); 416 _n_fine_entries++; 417 418 if (G1HRRSUseSparseTable) { 419 // Transfer from sparse to fine-grain. 420 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind); 421 assert(sprt_entry != NULL, "There should have been an entry"); 422 for (int i = 0; i < sprt_entry->num_valid_cards(); i++) { 423 CardIdx_t c = sprt_entry->card(i); 424 prt->add_card(c); 425 } 426 // Now we can delete the sparse entry. 427 bool res = _sparse_table.delete_entry(from_hrm_ind); 428 assert(res, "It should have been there."); 429 } 430 } 431 assert(prt != NULL && prt->hr() == from_hr, "consequence"); 432 } 433 // Note that we can't assert "prt->hr() == from_hr", because of the 434 // possibility of concurrent reuse. But see head comment of 435 // OtherRegionsTable for why this is OK. 436 assert(prt != NULL, "Inv"); 437 438 prt->add_reference(from); 439 assert(contains_reference(from), "We just added " PTR_FORMAT " to the PRT", p2i(from)); 440 } 441 442 PerRegionTable* 443 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const { 444 assert(ind < _max_fine_entries, "Preconditions."); 445 PerRegionTable* prt = _fine_grain_regions[ind]; 446 while (prt != NULL && prt->hr() != hr) { 447 prt = prt->collision_list_next(); 448 } 449 // Loop postcondition is the method postcondition. 450 return prt; 451 } 452 453 jint OtherRegionsTable::_n_coarsenings = 0; 454 455 PerRegionTable* OtherRegionsTable::delete_region_table() { 456 assert(_m->owned_by_self(), "Precondition"); 457 assert(_n_fine_entries == _max_fine_entries, "Precondition"); 458 PerRegionTable* max = NULL; 459 jint max_occ = 0; 460 PerRegionTable** max_prev = NULL; 461 size_t max_ind; 462 463 size_t i = _fine_eviction_start; 464 for (size_t k = 0; k < _fine_eviction_sample_size; k++) { 465 size_t ii = i; 466 // Make sure we get a non-NULL sample. 467 while (_fine_grain_regions[ii] == NULL) { 468 ii++; 469 if (ii == _max_fine_entries) ii = 0; 470 guarantee(ii != i, "We must find one."); 471 } 472 PerRegionTable** prev = &_fine_grain_regions[ii]; 473 PerRegionTable* cur = *prev; 474 while (cur != NULL) { 475 jint cur_occ = cur->occupied(); 476 if (max == NULL || cur_occ > max_occ) { 477 max = cur; 478 max_prev = prev; 479 max_ind = i; 480 max_occ = cur_occ; 481 } 482 prev = cur->collision_list_next_addr(); 483 cur = cur->collision_list_next(); 484 } 485 i = i + _fine_eviction_stride; 486 if (i >= _n_fine_entries) i = i - _n_fine_entries; 487 } 488 489 _fine_eviction_start++; 490 491 if (_fine_eviction_start >= _n_fine_entries) { 492 _fine_eviction_start -= _n_fine_entries; 493 } 494 495 guarantee(max != NULL, "Since _n_fine_entries > 0"); 496 guarantee(max_prev != NULL, "Since max != NULL."); 497 498 // Set the corresponding coarse bit. 499 size_t max_hrm_index = (size_t) max->hr()->hrm_index(); 500 if (!_coarse_map.at(max_hrm_index)) { 501 _coarse_map.at_put(max_hrm_index, true); 502 _n_coarse_entries++; 503 } 504 505 // Unsplice. 506 *max_prev = max->collision_list_next(); 507 Atomic::inc(&_n_coarsenings); 508 _n_fine_entries--; 509 return max; 510 } 511 512 void OtherRegionsTable::scrub(G1CardLiveData* live_data) { 513 // First eliminated garbage regions from the coarse map. 514 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index()); 515 516 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries); 517 if (_n_coarse_entries > 0) { 518 live_data->remove_nonlive_regions(&_coarse_map); 519 _n_coarse_entries = _coarse_map.count_one_bits(); 520 } 521 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries); 522 523 // Now do the fine-grained maps. 524 for (size_t i = 0; i < _max_fine_entries; i++) { 525 PerRegionTable* cur = _fine_grain_regions[i]; 526 PerRegionTable** prev = &_fine_grain_regions[i]; 527 while (cur != NULL) { 528 PerRegionTable* nxt = cur->collision_list_next(); 529 // If the entire region is dead, eliminate. 530 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index()); 531 if (!live_data->is_region_live(cur->hr()->hrm_index())) { 532 *prev = nxt; 533 cur->set_collision_list_next(NULL); 534 _n_fine_entries--; 535 log_develop_trace(gc, remset, scrub)(" deleted via region map."); 536 unlink_from_all(cur); 537 PerRegionTable::free(cur); 538 } else { 539 // Do fine-grain elimination. 540 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied()); 541 cur->scrub(live_data); 542 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied()); 543 // Did that empty the table completely? 544 if (cur->occupied() == 0) { 545 *prev = nxt; 546 cur->set_collision_list_next(NULL); 547 _n_fine_entries--; 548 unlink_from_all(cur); 549 PerRegionTable::free(cur); 550 } else { 551 prev = cur->collision_list_next_addr(); 552 } 553 } 554 cur = nxt; 555 } 556 } 557 // Since we may have deleted a from_card_cache entry from the RS, clear 558 // the FCC. 559 clear_fcc(); 560 } 561 562 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const { 563 if (limit <= (size_t)G1RSetSparseRegionEntries) { 564 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit; 565 } else { 566 // Current uses of this method may only use values less than G1RSetSparseRegionEntries 567 // for the limit. The solution, comparing against occupied() would be too slow 568 // at this time. 569 Unimplemented(); 570 return false; 571 } 572 } 573 574 bool OtherRegionsTable::is_empty() const { 575 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL; 576 } 577 578 size_t OtherRegionsTable::occupied() const { 579 size_t sum = occ_fine(); 580 sum += occ_sparse(); 581 sum += occ_coarse(); 582 return sum; 583 } 584 585 size_t OtherRegionsTable::occ_fine() const { 586 size_t sum = 0; 587 588 size_t num = 0; 589 PerRegionTable * cur = _first_all_fine_prts; 590 while (cur != NULL) { 591 sum += cur->occupied(); 592 cur = cur->next(); 593 num++; 594 } 595 guarantee(num == _n_fine_entries, "just checking"); 596 return sum; 597 } 598 599 size_t OtherRegionsTable::occ_coarse() const { 600 return (_n_coarse_entries * HeapRegion::CardsPerRegion); 601 } 602 603 size_t OtherRegionsTable::occ_sparse() const { 604 return _sparse_table.occupied(); 605 } 606 607 size_t OtherRegionsTable::mem_size() const { 608 size_t sum = 0; 609 // all PRTs are of the same size so it is sufficient to query only one of them. 610 if (_first_all_fine_prts != NULL) { 611 assert(_last_all_fine_prts != NULL && 612 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant"); 613 sum += _first_all_fine_prts->mem_size() * _n_fine_entries; 614 } 615 sum += (sizeof(PerRegionTable*) * _max_fine_entries); 616 sum += (_coarse_map.size_in_words() * HeapWordSize); 617 sum += (_sparse_table.mem_size()); 618 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above. 619 return sum; 620 } 621 622 size_t OtherRegionsTable::static_mem_size() { 623 return G1FromCardCache::static_mem_size(); 624 } 625 626 size_t OtherRegionsTable::fl_mem_size() { 627 return PerRegionTable::fl_mem_size(); 628 } 629 630 void OtherRegionsTable::clear_fcc() { 631 G1FromCardCache::clear(_hr->hrm_index()); 632 } 633 634 void OtherRegionsTable::clear() { 635 // if there are no entries, skip this step 636 if (_first_all_fine_prts != NULL) { 637 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking"); 638 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts); 639 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0])); 640 } else { 641 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking"); 642 } 643 644 _first_all_fine_prts = _last_all_fine_prts = NULL; 645 _sparse_table.clear(); 646 if (_n_coarse_entries > 0) { 647 _coarse_map.clear(); 648 } 649 _n_fine_entries = 0; 650 _n_coarse_entries = 0; 651 652 clear_fcc(); 653 } 654 655 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const { 656 // Cast away const in this case. 657 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag); 658 return contains_reference_locked(from); 659 } 660 661 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const { 662 HeapRegion* hr = _g1h->heap_region_containing(from); 663 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index(); 664 // Is this region in the coarse map? 665 if (_coarse_map.at(hr_ind)) return true; 666 667 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask, 668 hr); 669 if (prt != NULL) { 670 return prt->contains_reference(from); 671 672 } else { 673 uintptr_t from_card = 674 (uintptr_t(from) >> CardTableModRefBS::card_shift); 675 uintptr_t hr_bot_card_index = 676 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift; 677 assert(from_card >= hr_bot_card_index, "Inv"); 678 CardIdx_t card_index = from_card - hr_bot_card_index; 679 assert((size_t)card_index < HeapRegion::CardsPerRegion, 680 "Must be in range."); 681 return _sparse_table.contains_card(hr_ind, card_index); 682 } 683 } 684 685 void 686 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 687 _sparse_table.do_cleanup_work(hrrs_cleanup_task); 688 } 689 690 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetTable* bot, 691 HeapRegion* hr) 692 : _bot(bot), 693 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never), 694 _code_roots(), 695 _other_regions(hr, &_m) { 696 } 697 698 void HeapRegionRemSet::setup_remset_size() { 699 // Setup sparse and fine-grain tables sizes. 700 // table_size = base * (log(region_size / 1M) + 1) 701 const int LOG_M = 20; 702 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0); 703 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) { 704 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1); 705 } 706 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) { 707 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1); 708 } 709 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity"); 710 } 711 712 void HeapRegionRemSet::cleanup() { 713 SparsePRT::cleanup_all(); 714 } 715 716 void HeapRegionRemSet::clear() { 717 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); 718 clear_locked(); 719 } 720 721 void HeapRegionRemSet::clear_locked() { 722 _code_roots.clear(); 723 _other_regions.clear(); 724 assert(occupied_locked() == 0, "Should be clear."); 725 } 726 727 void HeapRegionRemSet::scrub(G1CardLiveData* live_data) { 728 _other_regions.scrub(live_data); 729 } 730 731 // Code roots support 732 // 733 // The code root set is protected by two separate locking schemes 734 // When at safepoint the per-hrrs lock must be held during modifications 735 // except when doing a full gc. 736 // When not at safepoint the CodeCache_lock must be held during modifications. 737 // When concurrent readers access the contains() function 738 // (during the evacuation phase) no removals are allowed. 739 740 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) { 741 assert(nm != NULL, "sanity"); 742 assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()), 743 "should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s", 744 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint())); 745 // Optimistic unlocked contains-check 746 if (!_code_roots.contains(nm)) { 747 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag); 748 add_strong_code_root_locked(nm); 749 } 750 } 751 752 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) { 753 assert(nm != NULL, "sanity"); 754 assert((CodeCache_lock->owned_by_self() || 755 (SafepointSynchronize::is_at_safepoint() && 756 (_m.owned_by_self() || Thread::current()->is_VM_thread()))), 757 "not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s", 758 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), 759 BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread())); 760 _code_roots.add(nm); 761 } 762 763 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) { 764 assert(nm != NULL, "sanity"); 765 assert_locked_or_safepoint(CodeCache_lock); 766 767 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag); 768 _code_roots.remove(nm); 769 770 // Check that there were no duplicates 771 guarantee(!_code_roots.contains(nm), "duplicate entry found"); 772 } 773 774 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const { 775 _code_roots.nmethods_do(blk); 776 } 777 778 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) { 779 _code_roots.clean(hr); 780 } 781 782 size_t HeapRegionRemSet::strong_code_roots_mem_size() { 783 return _code_roots.mem_size(); 784 } 785 786 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) : 787 _hrrs(hrrs), 788 _g1h(G1CollectedHeap::heap()), 789 _coarse_map(&hrrs->_other_regions._coarse_map), 790 _bot(hrrs->_bot), 791 _is(Sparse), 792 // Set these values so that we increment to the first region. 793 _coarse_cur_region_index(-1), 794 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1), 795 _cur_card_in_prt(HeapRegion::CardsPerRegion), 796 _fine_cur_prt(NULL), 797 _n_yielded_coarse(0), 798 _n_yielded_fine(0), 799 _n_yielded_sparse(0), 800 _sparse_iter(&hrrs->_other_regions._sparse_table) {} 801 802 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) { 803 if (_hrrs->_other_regions._n_coarse_entries == 0) return false; 804 // Go to the next card. 805 _coarse_cur_region_cur_card++; 806 // Was the last the last card in the current region? 807 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) { 808 // Yes: find the next region. This may leave _coarse_cur_region_index 809 // Set to the last index, in which case there are no more coarse 810 // regions. 811 _coarse_cur_region_index = 812 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1); 813 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) { 814 _coarse_cur_region_cur_card = 0; 815 HeapWord* r_bot = 816 _g1h->region_at((uint) _coarse_cur_region_index)->bottom(); 817 _cur_region_card_offset = _bot->index_for(r_bot); 818 } else { 819 return false; 820 } 821 } 822 // If we didn't return false above, then we can yield a card. 823 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card; 824 return true; 825 } 826 827 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) { 828 if (fine_has_next()) { 829 _cur_card_in_prt = 830 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 831 } 832 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) { 833 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for 834 // the remembered set. 835 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) { 836 return false; 837 } 838 PerRegionTable* next_prt = _fine_cur_prt->next(); 839 switch_to_prt(next_prt); 840 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 841 } 842 843 card_index = _cur_region_card_offset + _cur_card_in_prt; 844 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion, 845 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt); 846 return true; 847 } 848 849 bool HeapRegionRemSetIterator::fine_has_next() { 850 return _cur_card_in_prt != HeapRegion::CardsPerRegion; 851 } 852 853 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) { 854 assert(prt != NULL, "Cannot switch to NULL prt"); 855 _fine_cur_prt = prt; 856 857 HeapWord* r_bot = _fine_cur_prt->hr()->bottom(); 858 _cur_region_card_offset = _bot->index_for(r_bot); 859 860 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1. 861 // To avoid special-casing this start case, and not miss the first bitmap 862 // entry, initialize _cur_region_cur_card with -1 instead of 0. 863 _cur_card_in_prt = (size_t)-1; 864 } 865 866 bool HeapRegionRemSetIterator::has_next(size_t& card_index) { 867 switch (_is) { 868 case Sparse: { 869 if (_sparse_iter.has_next(card_index)) { 870 _n_yielded_sparse++; 871 return true; 872 } 873 // Otherwise, deliberate fall-through 874 _is = Fine; 875 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts; 876 if (initial_fine_prt != NULL) { 877 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts); 878 } 879 } 880 case Fine: 881 if (fine_has_next(card_index)) { 882 _n_yielded_fine++; 883 return true; 884 } 885 // Otherwise, deliberate fall-through 886 _is = Coarse; 887 case Coarse: 888 if (coarse_has_next(card_index)) { 889 _n_yielded_coarse++; 890 return true; 891 } 892 // Otherwise... 893 break; 894 } 895 return false; 896 } 897 898 void HeapRegionRemSet::reset_for_cleanup_tasks() { 899 SparsePRT::reset_for_cleanup_tasks(); 900 } 901 902 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 903 _other_regions.do_cleanup_work(hrrs_cleanup_task); 904 } 905 906 void 907 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) { 908 SparsePRT::finish_cleanup_task(hrrs_cleanup_task); 909 } 910 911 #ifndef PRODUCT 912 void HeapRegionRemSet::test() { 913 os::sleep(Thread::current(), (jlong)5000, false); 914 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 915 916 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same 917 // hash bucket. 918 HeapRegion* hr0 = g1h->region_at(0); 919 HeapRegion* hr1 = g1h->region_at(1); 920 HeapRegion* hr2 = g1h->region_at(5); 921 HeapRegion* hr3 = g1h->region_at(6); 922 HeapRegion* hr4 = g1h->region_at(7); 923 HeapRegion* hr5 = g1h->region_at(8); 924 925 HeapWord* hr1_start = hr1->bottom(); 926 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2; 927 HeapWord* hr1_last = hr1->end() - 1; 928 929 HeapWord* hr2_start = hr2->bottom(); 930 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2; 931 HeapWord* hr2_last = hr2->end() - 1; 932 933 HeapWord* hr3_start = hr3->bottom(); 934 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2; 935 HeapWord* hr3_last = hr3->end() - 1; 936 937 HeapRegionRemSet* hrrs = hr0->rem_set(); 938 939 // Make three references from region 0x101... 940 hrrs->add_reference((OopOrNarrowOopStar)hr1_start); 941 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid); 942 hrrs->add_reference((OopOrNarrowOopStar)hr1_last); 943 944 hrrs->add_reference((OopOrNarrowOopStar)hr2_start); 945 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid); 946 hrrs->add_reference((OopOrNarrowOopStar)hr2_last); 947 948 hrrs->add_reference((OopOrNarrowOopStar)hr3_start); 949 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid); 950 hrrs->add_reference((OopOrNarrowOopStar)hr3_last); 951 952 // Now cause a coarsening. 953 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom()); 954 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom()); 955 956 // Now, does iteration yield these three? 957 HeapRegionRemSetIterator iter(hrrs); 958 size_t sum = 0; 959 size_t card_index; 960 while (iter.has_next(card_index)) { 961 HeapWord* card_start = 962 G1CollectedHeap::heap()->bot()->address_for_index(card_index); 963 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start)); 964 sum++; 965 } 966 guarantee(sum == 11 - 3 + 2048, "Failure"); 967 guarantee(sum == hrrs->occupied(), "Failure"); 968 } 969 #endif