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/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 CHeapBitMap _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), 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((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 _fine_grain_regions(NULL), 264 _first_all_fine_prts(NULL), _last_all_fine_prts(NULL), 265 _n_fine_entries(0), _n_coarse_entries(0), 266 _fine_eviction_start(0), 267 _sparse_table(hr) 268 { 269 typedef PerRegionTable* PerRegionTablePtr; 270 271 if (_max_fine_entries == 0) { 272 assert(_mod_max_fine_entries_mask == 0, "Both or none."); 273 size_t max_entries_log = (size_t)log2_long((jlong)G1RSetRegionEntries); 274 _max_fine_entries = (size_t)1 << max_entries_log; 275 _mod_max_fine_entries_mask = _max_fine_entries - 1; 276 277 assert(_fine_eviction_sample_size == 0 278 && _fine_eviction_stride == 0, "All init at same time."); 279 _fine_eviction_sample_size = MAX2((size_t)4, max_entries_log); 280 _fine_eviction_stride = _max_fine_entries / _fine_eviction_sample_size; 281 } 282 283 _fine_grain_regions = NEW_C_HEAP_ARRAY3(PerRegionTablePtr, _max_fine_entries, 284 mtGC, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 285 286 if (_fine_grain_regions == NULL) { 287 vm_exit_out_of_memory(sizeof(void*)*_max_fine_entries, OOM_MALLOC_ERROR, 288 "Failed to allocate _fine_grain_entries."); 289 } 290 291 for (size_t i = 0; i < _max_fine_entries; i++) { 292 _fine_grain_regions[i] = NULL; 293 } 294 } 295 296 void OtherRegionsTable::link_to_all(PerRegionTable* prt) { 297 // We always append to the beginning of the list for convenience; 298 // the order of entries in this list does not matter. 299 if (_first_all_fine_prts != NULL) { 300 assert(_first_all_fine_prts->prev() == NULL, "invariant"); 301 _first_all_fine_prts->set_prev(prt); 302 prt->set_next(_first_all_fine_prts); 303 } else { 304 // this is the first element we insert. Adjust the "last" pointer 305 _last_all_fine_prts = prt; 306 assert(prt->next() == NULL, "just checking"); 307 } 308 // the new element is always the first element without a predecessor 309 prt->set_prev(NULL); 310 _first_all_fine_prts = prt; 311 312 assert(prt->prev() == NULL, "just checking"); 313 assert(_first_all_fine_prts == prt, "just checking"); 314 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 315 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 316 "just checking"); 317 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 318 "just checking"); 319 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 320 "just checking"); 321 } 322 323 void OtherRegionsTable::unlink_from_all(PerRegionTable* prt) { 324 if (prt->prev() != NULL) { 325 assert(_first_all_fine_prts != prt, "just checking"); 326 prt->prev()->set_next(prt->next()); 327 // removing the last element in the list? 328 if (_last_all_fine_prts == prt) { 329 _last_all_fine_prts = prt->prev(); 330 } 331 } else { 332 assert(_first_all_fine_prts == prt, "just checking"); 333 _first_all_fine_prts = prt->next(); 334 // list is empty now? 335 if (_first_all_fine_prts == NULL) { 336 _last_all_fine_prts = NULL; 337 } 338 } 339 340 if (prt->next() != NULL) { 341 prt->next()->set_prev(prt->prev()); 342 } 343 344 prt->set_next(NULL); 345 prt->set_prev(NULL); 346 347 assert((_first_all_fine_prts == NULL && _last_all_fine_prts == NULL) || 348 (_first_all_fine_prts != NULL && _last_all_fine_prts != NULL), 349 "just checking"); 350 assert(_last_all_fine_prts == NULL || _last_all_fine_prts->next() == NULL, 351 "just checking"); 352 assert(_first_all_fine_prts == NULL || _first_all_fine_prts->prev() == NULL, 353 "just checking"); 354 } 355 356 void OtherRegionsTable::add_reference(OopOrNarrowOopStar from, uint tid) { 357 uint cur_hrm_ind = _hr->hrm_index(); 358 359 int from_card = (int)(uintptr_t(from) >> CardTableModRefBS::card_shift); 360 361 if (G1FromCardCache::contains_or_replace(tid, cur_hrm_ind, from_card)) { 362 assert(contains_reference(from), "We just found " PTR_FORMAT " in the FromCardCache", p2i(from)); 363 return; 364 } 365 366 // Note that this may be a continued H region. 367 HeapRegion* from_hr = _g1h->heap_region_containing(from); 368 RegionIdx_t from_hrm_ind = (RegionIdx_t) from_hr->hrm_index(); 369 370 // If the region is already coarsened, return. 371 if (_coarse_map.at(from_hrm_ind)) { 372 assert(contains_reference(from), "We just found " PTR_FORMAT " in the Coarse table", p2i(from)); 373 return; 374 } 375 376 // Otherwise find a per-region table to add it to. 377 size_t ind = from_hrm_ind & _mod_max_fine_entries_mask; 378 PerRegionTable* prt = find_region_table(ind, from_hr); 379 if (prt == NULL) { 380 MutexLockerEx x(_m, Mutex::_no_safepoint_check_flag); 381 // Confirm that it's really not there... 382 prt = find_region_table(ind, from_hr); 383 if (prt == NULL) { 384 385 uintptr_t from_hr_bot_card_index = 386 uintptr_t(from_hr->bottom()) 387 >> CardTableModRefBS::card_shift; 388 CardIdx_t card_index = from_card - from_hr_bot_card_index; 389 assert((size_t)card_index < HeapRegion::CardsPerRegion, 390 "Must be in range."); 391 if (G1HRRSUseSparseTable && 392 _sparse_table.add_card(from_hrm_ind, card_index)) { 393 assert(contains_reference_locked(from), "We just added " PTR_FORMAT " to the Sparse table", p2i(from)); 394 return; 395 } 396 397 if (_n_fine_entries == _max_fine_entries) { 398 prt = delete_region_table(); 399 // There is no need to clear the links to the 'all' list here: 400 // prt will be reused immediately, i.e. remain in the 'all' list. 401 prt->init(from_hr, false /* clear_links_to_all_list */); 402 } else { 403 prt = PerRegionTable::alloc(from_hr); 404 link_to_all(prt); 405 } 406 407 PerRegionTable* first_prt = _fine_grain_regions[ind]; 408 prt->set_collision_list_next(first_prt); 409 // The assignment into _fine_grain_regions allows the prt to 410 // start being used concurrently. In addition to 411 // collision_list_next which must be visible (else concurrent 412 // parsing of the list, if any, may fail to see other entries), 413 // the content of the prt must be visible (else for instance 414 // some mark bits may not yet seem cleared or a 'later' update 415 // performed by a concurrent thread could be undone when the 416 // zeroing becomes visible). This requires store ordering. 417 OrderAccess::release_store_ptr((volatile PerRegionTable*)&_fine_grain_regions[ind], prt); 418 _n_fine_entries++; 419 420 if (G1HRRSUseSparseTable) { 421 // Transfer from sparse to fine-grain. 422 SparsePRTEntry *sprt_entry = _sparse_table.get_entry(from_hrm_ind); 423 assert(sprt_entry != NULL, "There should have been an entry"); 424 for (int i = 0; i < sprt_entry->num_valid_cards(); i++) { 425 CardIdx_t c = sprt_entry->card(i); 426 prt->add_card(c); 427 } 428 // Now we can delete the sparse entry. 429 bool res = _sparse_table.delete_entry(from_hrm_ind); 430 assert(res, "It should have been there."); 431 } 432 } 433 assert(prt != NULL && prt->hr() == from_hr, "consequence"); 434 } 435 // Note that we can't assert "prt->hr() == from_hr", because of the 436 // possibility of concurrent reuse. But see head comment of 437 // OtherRegionsTable for why this is OK. 438 assert(prt != NULL, "Inv"); 439 440 prt->add_reference(from); 441 assert(contains_reference(from), "We just added " PTR_FORMAT " to the PRT", p2i(from)); 442 } 443 444 PerRegionTable* 445 OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const { 446 assert(ind < _max_fine_entries, "Preconditions."); 447 PerRegionTable* prt = _fine_grain_regions[ind]; 448 while (prt != NULL && prt->hr() != hr) { 449 prt = prt->collision_list_next(); 450 } 451 // Loop postcondition is the method postcondition. 452 return prt; 453 } 454 455 jint OtherRegionsTable::_n_coarsenings = 0; 456 457 PerRegionTable* OtherRegionsTable::delete_region_table() { 458 assert(_m->owned_by_self(), "Precondition"); 459 assert(_n_fine_entries == _max_fine_entries, "Precondition"); 460 PerRegionTable* max = NULL; 461 jint max_occ = 0; 462 PerRegionTable** max_prev = NULL; 463 size_t max_ind; 464 465 size_t i = _fine_eviction_start; 466 for (size_t k = 0; k < _fine_eviction_sample_size; k++) { 467 size_t ii = i; 468 // Make sure we get a non-NULL sample. 469 while (_fine_grain_regions[ii] == NULL) { 470 ii++; 471 if (ii == _max_fine_entries) ii = 0; 472 guarantee(ii != i, "We must find one."); 473 } 474 PerRegionTable** prev = &_fine_grain_regions[ii]; 475 PerRegionTable* cur = *prev; 476 while (cur != NULL) { 477 jint cur_occ = cur->occupied(); 478 if (max == NULL || cur_occ > max_occ) { 479 max = cur; 480 max_prev = prev; 481 max_ind = i; 482 max_occ = cur_occ; 483 } 484 prev = cur->collision_list_next_addr(); 485 cur = cur->collision_list_next(); 486 } 487 i = i + _fine_eviction_stride; 488 if (i >= _n_fine_entries) i = i - _n_fine_entries; 489 } 490 491 _fine_eviction_start++; 492 493 if (_fine_eviction_start >= _n_fine_entries) { 494 _fine_eviction_start -= _n_fine_entries; 495 } 496 497 guarantee(max != NULL, "Since _n_fine_entries > 0"); 498 guarantee(max_prev != NULL, "Since max != NULL."); 499 500 // Set the corresponding coarse bit. 501 size_t max_hrm_index = (size_t) max->hr()->hrm_index(); 502 if (!_coarse_map.at(max_hrm_index)) { 503 _coarse_map.at_put(max_hrm_index, true); 504 _n_coarse_entries++; 505 } 506 507 // Unsplice. 508 *max_prev = max->collision_list_next(); 509 Atomic::inc(&_n_coarsenings); 510 _n_fine_entries--; 511 return max; 512 } 513 514 void OtherRegionsTable::scrub(G1CardLiveData* live_data) { 515 // First eliminated garbage regions from the coarse map. 516 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index()); 517 518 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries); 519 if (_n_coarse_entries > 0) { 520 live_data->remove_nonlive_regions(&_coarse_map); 521 _n_coarse_entries = _coarse_map.count_one_bits(); 522 } 523 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries); 524 525 // Now do the fine-grained maps. 526 for (size_t i = 0; i < _max_fine_entries; i++) { 527 PerRegionTable* cur = _fine_grain_regions[i]; 528 PerRegionTable** prev = &_fine_grain_regions[i]; 529 while (cur != NULL) { 530 PerRegionTable* nxt = cur->collision_list_next(); 531 // If the entire region is dead, eliminate. 532 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index()); 533 if (!live_data->is_region_live(cur->hr()->hrm_index())) { 534 *prev = nxt; 535 cur->set_collision_list_next(NULL); 536 _n_fine_entries--; 537 log_develop_trace(gc, remset, scrub)(" deleted via region map."); 538 unlink_from_all(cur); 539 PerRegionTable::free(cur); 540 } else { 541 // Do fine-grain elimination. 542 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied()); 543 cur->scrub(live_data); 544 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied()); 545 // Did that empty the table completely? 546 if (cur->occupied() == 0) { 547 *prev = nxt; 548 cur->set_collision_list_next(NULL); 549 _n_fine_entries--; 550 unlink_from_all(cur); 551 PerRegionTable::free(cur); 552 } else { 553 prev = cur->collision_list_next_addr(); 554 } 555 } 556 cur = nxt; 557 } 558 } 559 // Since we may have deleted a from_card_cache entry from the RS, clear 560 // the FCC. 561 clear_fcc(); 562 } 563 564 bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const { 565 if (limit <= (size_t)G1RSetSparseRegionEntries) { 566 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit; 567 } else { 568 // Current uses of this method may only use values less than G1RSetSparseRegionEntries 569 // for the limit. The solution, comparing against occupied() would be too slow 570 // at this time. 571 Unimplemented(); 572 return false; 573 } 574 } 575 576 bool OtherRegionsTable::is_empty() const { 577 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL; 578 } 579 580 size_t OtherRegionsTable::occupied() const { 581 size_t sum = occ_fine(); 582 sum += occ_sparse(); 583 sum += occ_coarse(); 584 return sum; 585 } 586 587 size_t OtherRegionsTable::occ_fine() const { 588 size_t sum = 0; 589 590 size_t num = 0; 591 PerRegionTable * cur = _first_all_fine_prts; 592 while (cur != NULL) { 593 sum += cur->occupied(); 594 cur = cur->next(); 595 num++; 596 } 597 guarantee(num == _n_fine_entries, "just checking"); 598 return sum; 599 } 600 601 size_t OtherRegionsTable::occ_coarse() const { 602 return (_n_coarse_entries * HeapRegion::CardsPerRegion); 603 } 604 605 size_t OtherRegionsTable::occ_sparse() const { 606 return _sparse_table.occupied(); 607 } 608 609 size_t OtherRegionsTable::mem_size() const { 610 size_t sum = 0; 611 // all PRTs are of the same size so it is sufficient to query only one of them. 612 if (_first_all_fine_prts != NULL) { 613 assert(_last_all_fine_prts != NULL && 614 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant"); 615 sum += _first_all_fine_prts->mem_size() * _n_fine_entries; 616 } 617 sum += (sizeof(PerRegionTable*) * _max_fine_entries); 618 sum += (_coarse_map.size_in_words() * HeapWordSize); 619 sum += (_sparse_table.mem_size()); 620 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above. 621 return sum; 622 } 623 624 size_t OtherRegionsTable::static_mem_size() { 625 return G1FromCardCache::static_mem_size(); 626 } 627 628 size_t OtherRegionsTable::fl_mem_size() { 629 return PerRegionTable::fl_mem_size(); 630 } 631 632 void OtherRegionsTable::clear_fcc() { 633 G1FromCardCache::clear(_hr->hrm_index()); 634 } 635 636 void OtherRegionsTable::clear() { 637 // if there are no entries, skip this step 638 if (_first_all_fine_prts != NULL) { 639 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking"); 640 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts); 641 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0])); 642 } else { 643 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking"); 644 } 645 646 _first_all_fine_prts = _last_all_fine_prts = NULL; 647 _sparse_table.clear(); 648 if (_n_coarse_entries > 0) { 649 _coarse_map.clear(); 650 } 651 _n_fine_entries = 0; 652 _n_coarse_entries = 0; 653 654 clear_fcc(); 655 } 656 657 bool OtherRegionsTable::contains_reference(OopOrNarrowOopStar from) const { 658 // Cast away const in this case. 659 MutexLockerEx x((Mutex*)_m, Mutex::_no_safepoint_check_flag); 660 return contains_reference_locked(from); 661 } 662 663 bool OtherRegionsTable::contains_reference_locked(OopOrNarrowOopStar from) const { 664 HeapRegion* hr = _g1h->heap_region_containing(from); 665 RegionIdx_t hr_ind = (RegionIdx_t) hr->hrm_index(); 666 // Is this region in the coarse map? 667 if (_coarse_map.at(hr_ind)) return true; 668 669 PerRegionTable* prt = find_region_table(hr_ind & _mod_max_fine_entries_mask, 670 hr); 671 if (prt != NULL) { 672 return prt->contains_reference(from); 673 674 } else { 675 uintptr_t from_card = 676 (uintptr_t(from) >> CardTableModRefBS::card_shift); 677 uintptr_t hr_bot_card_index = 678 uintptr_t(hr->bottom()) >> CardTableModRefBS::card_shift; 679 assert(from_card >= hr_bot_card_index, "Inv"); 680 CardIdx_t card_index = from_card - hr_bot_card_index; 681 assert((size_t)card_index < HeapRegion::CardsPerRegion, 682 "Must be in range."); 683 return _sparse_table.contains_card(hr_ind, card_index); 684 } 685 } 686 687 void 688 OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 689 _sparse_table.do_cleanup_work(hrrs_cleanup_task); 690 } 691 692 HeapRegionRemSet::HeapRegionRemSet(G1BlockOffsetTable* bot, 693 HeapRegion* hr) 694 : _bot(bot), 695 _m(Mutex::leaf, FormatBuffer<128>("HeapRegionRemSet lock #%u", hr->hrm_index()), true, Monitor::_safepoint_check_never), 696 _code_roots(), 697 _other_regions(hr, &_m) { 698 } 699 700 void HeapRegionRemSet::setup_remset_size() { 701 // Setup sparse and fine-grain tables sizes. 702 // table_size = base * (log(region_size / 1M) + 1) 703 const int LOG_M = 20; 704 int region_size_log_mb = MAX2(HeapRegion::LogOfHRGrainBytes - LOG_M, 0); 705 if (FLAG_IS_DEFAULT(G1RSetSparseRegionEntries)) { 706 G1RSetSparseRegionEntries = G1RSetSparseRegionEntriesBase * (region_size_log_mb + 1); 707 } 708 if (FLAG_IS_DEFAULT(G1RSetRegionEntries)) { 709 G1RSetRegionEntries = G1RSetRegionEntriesBase * (region_size_log_mb + 1); 710 } 711 guarantee(G1RSetSparseRegionEntries > 0 && G1RSetRegionEntries > 0 , "Sanity"); 712 } 713 714 void HeapRegionRemSet::cleanup() { 715 SparsePRT::cleanup_all(); 716 } 717 718 void HeapRegionRemSet::clear() { 719 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); 720 clear_locked(); 721 } 722 723 void HeapRegionRemSet::clear_locked() { 724 _code_roots.clear(); 725 _other_regions.clear(); 726 assert(occupied_locked() == 0, "Should be clear."); 727 } 728 729 void HeapRegionRemSet::scrub(G1CardLiveData* live_data) { 730 _other_regions.scrub(live_data); 731 } 732 733 // Code roots support 734 // 735 // The code root set is protected by two separate locking schemes 736 // When at safepoint the per-hrrs lock must be held during modifications 737 // except when doing a full gc. 738 // When not at safepoint the CodeCache_lock must be held during modifications. 739 // When concurrent readers access the contains() function 740 // (during the evacuation phase) no removals are allowed. 741 742 void HeapRegionRemSet::add_strong_code_root(nmethod* nm) { 743 assert(nm != NULL, "sanity"); 744 assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()), 745 "should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s", 746 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint())); 747 // Optimistic unlocked contains-check 748 if (!_code_roots.contains(nm)) { 749 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag); 750 add_strong_code_root_locked(nm); 751 } 752 } 753 754 void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) { 755 assert(nm != NULL, "sanity"); 756 assert((CodeCache_lock->owned_by_self() || 757 (SafepointSynchronize::is_at_safepoint() && 758 (_m.owned_by_self() || Thread::current()->is_VM_thread()))), 759 "not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s", 760 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), 761 BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread())); 762 _code_roots.add(nm); 763 } 764 765 void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) { 766 assert(nm != NULL, "sanity"); 767 assert_locked_or_safepoint(CodeCache_lock); 768 769 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag); 770 _code_roots.remove(nm); 771 772 // Check that there were no duplicates 773 guarantee(!_code_roots.contains(nm), "duplicate entry found"); 774 } 775 776 void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const { 777 _code_roots.nmethods_do(blk); 778 } 779 780 void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) { 781 _code_roots.clean(hr); 782 } 783 784 size_t HeapRegionRemSet::strong_code_roots_mem_size() { 785 return _code_roots.mem_size(); 786 } 787 788 HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) : 789 _hrrs(hrrs), 790 _g1h(G1CollectedHeap::heap()), 791 _coarse_map(&hrrs->_other_regions._coarse_map), 792 _bot(hrrs->_bot), 793 _is(Sparse), 794 // Set these values so that we increment to the first region. 795 _coarse_cur_region_index(-1), 796 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1), 797 _cur_card_in_prt(HeapRegion::CardsPerRegion), 798 _fine_cur_prt(NULL), 799 _n_yielded_coarse(0), 800 _n_yielded_fine(0), 801 _n_yielded_sparse(0), 802 _sparse_iter(&hrrs->_other_regions._sparse_table) {} 803 804 bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) { 805 if (_hrrs->_other_regions._n_coarse_entries == 0) return false; 806 // Go to the next card. 807 _coarse_cur_region_cur_card++; 808 // Was the last the last card in the current region? 809 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) { 810 // Yes: find the next region. This may leave _coarse_cur_region_index 811 // Set to the last index, in which case there are no more coarse 812 // regions. 813 _coarse_cur_region_index = 814 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1); 815 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) { 816 _coarse_cur_region_cur_card = 0; 817 HeapWord* r_bot = 818 _g1h->region_at((uint) _coarse_cur_region_index)->bottom(); 819 _cur_region_card_offset = _bot->index_for(r_bot); 820 } else { 821 return false; 822 } 823 } 824 // If we didn't return false above, then we can yield a card. 825 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card; 826 return true; 827 } 828 829 bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) { 830 if (fine_has_next()) { 831 _cur_card_in_prt = 832 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 833 } 834 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) { 835 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for 836 // the remembered set. 837 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) { 838 return false; 839 } 840 PerRegionTable* next_prt = _fine_cur_prt->next(); 841 switch_to_prt(next_prt); 842 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 843 } 844 845 card_index = _cur_region_card_offset + _cur_card_in_prt; 846 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion, 847 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt); 848 return true; 849 } 850 851 bool HeapRegionRemSetIterator::fine_has_next() { 852 return _cur_card_in_prt != HeapRegion::CardsPerRegion; 853 } 854 855 void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) { 856 assert(prt != NULL, "Cannot switch to NULL prt"); 857 _fine_cur_prt = prt; 858 859 HeapWord* r_bot = _fine_cur_prt->hr()->bottom(); 860 _cur_region_card_offset = _bot->index_for(r_bot); 861 862 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1. 863 // To avoid special-casing this start case, and not miss the first bitmap 864 // entry, initialize _cur_region_cur_card with -1 instead of 0. 865 _cur_card_in_prt = (size_t)-1; 866 } 867 868 bool HeapRegionRemSetIterator::has_next(size_t& card_index) { 869 switch (_is) { 870 case Sparse: { 871 if (_sparse_iter.has_next(card_index)) { 872 _n_yielded_sparse++; 873 return true; 874 } 875 // Otherwise, deliberate fall-through 876 _is = Fine; 877 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts; 878 if (initial_fine_prt != NULL) { 879 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts); 880 } 881 } 882 case Fine: 883 if (fine_has_next(card_index)) { 884 _n_yielded_fine++; 885 return true; 886 } 887 // Otherwise, deliberate fall-through 888 _is = Coarse; 889 case Coarse: 890 if (coarse_has_next(card_index)) { 891 _n_yielded_coarse++; 892 return true; 893 } 894 // Otherwise... 895 break; 896 } 897 return false; 898 } 899 900 void HeapRegionRemSet::reset_for_cleanup_tasks() { 901 SparsePRT::reset_for_cleanup_tasks(); 902 } 903 904 void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 905 _other_regions.do_cleanup_work(hrrs_cleanup_task); 906 } 907 908 void 909 HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) { 910 SparsePRT::finish_cleanup_task(hrrs_cleanup_task); 911 } 912 913 #ifndef PRODUCT 914 void HeapRegionRemSet::test() { 915 os::sleep(Thread::current(), (jlong)5000, false); 916 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 917 918 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same 919 // hash bucket. 920 HeapRegion* hr0 = g1h->region_at(0); 921 HeapRegion* hr1 = g1h->region_at(1); 922 HeapRegion* hr2 = g1h->region_at(5); 923 HeapRegion* hr3 = g1h->region_at(6); 924 HeapRegion* hr4 = g1h->region_at(7); 925 HeapRegion* hr5 = g1h->region_at(8); 926 927 HeapWord* hr1_start = hr1->bottom(); 928 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2; 929 HeapWord* hr1_last = hr1->end() - 1; 930 931 HeapWord* hr2_start = hr2->bottom(); 932 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2; 933 HeapWord* hr2_last = hr2->end() - 1; 934 935 HeapWord* hr3_start = hr3->bottom(); 936 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2; 937 HeapWord* hr3_last = hr3->end() - 1; 938 939 HeapRegionRemSet* hrrs = hr0->rem_set(); 940 941 // Make three references from region 0x101... 942 hrrs->add_reference((OopOrNarrowOopStar)hr1_start); 943 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid); 944 hrrs->add_reference((OopOrNarrowOopStar)hr1_last); 945 946 hrrs->add_reference((OopOrNarrowOopStar)hr2_start); 947 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid); 948 hrrs->add_reference((OopOrNarrowOopStar)hr2_last); 949 950 hrrs->add_reference((OopOrNarrowOopStar)hr3_start); 951 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid); 952 hrrs->add_reference((OopOrNarrowOopStar)hr3_last); 953 954 // Now cause a coarsening. 955 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom()); 956 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom()); 957 958 // Now, does iteration yield these three? 959 HeapRegionRemSetIterator iter(hrrs); 960 size_t sum = 0; 961 size_t card_index; 962 while (iter.has_next(card_index)) { 963 HeapWord* card_start = 964 G1CollectedHeap::heap()->bot()->address_for_index(card_index); 965 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start)); 966 sum++; 967 } 968 guarantee(sum == 11 - 3 + 2048, "Failure"); 969 guarantee(sum == hrrs->occupied(), "Failure"); 970 } 971 #endif