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 43class 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 63protected: 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 114public: 115 116 HeapRegion* hr() const { 117 return (HeapRegion*) OrderAccess::load_ptr_acquire(&_hr); 118 } 119 120 jint occupied() const { 121 // Overkill, but if we ever need it... 122 // guarantee(_occupied == _bm.count_one_bits(), "Check"); 123 return _occupied; 124 } 125 126 void init(HeapRegion* hr, bool clear_links_to_all_list) { 127 if (clear_links_to_all_list) { 128 set_next(NULL); 129 set_prev(NULL); 130 } 131 _collision_list_next = NULL; 132 _occupied = 0; 133 _bm.clear(); 134 // Make sure that the bitmap clearing above has been finished before publishing 135 // this PRT to concurrent threads. 136 OrderAccess::release_store_ptr(&_hr, hr); 137 } 138 139 void add_reference(OopOrNarrowOopStar from) { 140 add_reference_work(from, /*parallel*/ true); 141 } 142 143 void seq_add_reference(OopOrNarrowOopStar from) { 144 add_reference_work(from, /*parallel*/ false); 145 } 146 147 void scrub(G1CardLiveData* live_data) { 148 live_data->remove_nonlive_cards(hr()->hrm_index(), &_bm); 149 recount_occupied(); 150 } 151 152 void add_card(CardIdx_t from_card_index) { 153 add_card_work(from_card_index, /*parallel*/ true); 154 } 155 156 void seq_add_card(CardIdx_t from_card_index) { 157 add_card_work(from_card_index, /*parallel*/ false); 158 } 159 160 // (Destructively) union the bitmap of the current table into the given 161 // bitmap (which is assumed to be of the same size.) 162 void union_bitmap_into(BitMap* bm) { 163 bm->set_union(_bm); 164 } 165 166 // Mem size in bytes. 167 size_t mem_size() const { 168 return sizeof(PerRegionTable) + _bm.size_in_words() * HeapWordSize; 169 } 170 171 // Requires "from" to be in "hr()". 172 bool contains_reference(OopOrNarrowOopStar from) const { 173 assert(hr()->is_in_reserved(from), "Precondition."); 174 size_t card_ind = pointer_delta(from, hr()->bottom(), 175 CardTableModRefBS::card_size); 176 return _bm.at(card_ind); 177 } 178 179 // Bulk-free the PRTs from prt to last, assumes that they are 180 // linked together using their _next field. 181 static void bulk_free(PerRegionTable* prt, PerRegionTable* last) { 182 while (true) { 183 PerRegionTable* fl = _free_list; 184 last->set_next(fl); 185 PerRegionTable* res = (PerRegionTable*) Atomic::cmpxchg_ptr(prt, &_free_list, fl); 186 if (res == fl) { 187 return; 188 } 189 } 190 ShouldNotReachHere(); 191 } 192 193 static void free(PerRegionTable* prt) { 194 bulk_free(prt, prt); 195 } 196 197 // Returns an initialized PerRegionTable instance. 198 static PerRegionTable* alloc(HeapRegion* hr) { 199 PerRegionTable* fl = _free_list; 200 while (fl != NULL) { 201 PerRegionTable* nxt = fl->next(); 202 PerRegionTable* res = 203 (PerRegionTable*) 204 Atomic::cmpxchg_ptr(nxt, &_free_list, fl); 205 if (res == fl) { 206 fl->init(hr, true); 207 return fl; 208 } else { 209 fl = _free_list; 210 } 211 } 212 assert(fl == NULL, "Loop condition."); 213 return new PerRegionTable(hr); 214 } 215 216 PerRegionTable* next() const { return _next; } 217 void set_next(PerRegionTable* next) { _next = next; } 218 PerRegionTable* prev() const { return _prev; } 219 void set_prev(PerRegionTable* prev) { _prev = prev; } 220 221 // Accessor and Modification routines for the pointer for the 222 // singly linked collision list that links the PRTs within the 223 // OtherRegionsTable::_fine_grain_regions hash table. 224 // 225 // It might be useful to also make the collision list doubly linked 226 // to avoid iteration over the collisions list during scrubbing/deletion. 227 // OTOH there might not be many collisions. 228 229 PerRegionTable* collision_list_next() const { 230 return _collision_list_next; 231 } 232 233 void set_collision_list_next(PerRegionTable* next) { 234 _collision_list_next = next; 235 } 236 237 PerRegionTable** collision_list_next_addr() { 238 return &_collision_list_next; 239 } 240 241 static size_t fl_mem_size() { 242 PerRegionTable* cur = _free_list; 243 size_t res = 0; 244 while (cur != NULL) { 245 res += cur->mem_size(); 246 cur = cur->next(); 247 } 248 return res; 249 } 250 251 static void test_fl_mem_size(); 252}; 253 254PerRegionTable* volatile PerRegionTable::_free_list = NULL; 255 256size_t OtherRegionsTable::_max_fine_entries = 0; 257size_t OtherRegionsTable::_mod_max_fine_entries_mask = 0; 258size_t OtherRegionsTable::_fine_eviction_stride = 0; 259size_t OtherRegionsTable::_fine_eviction_sample_size = 0; 260 261OtherRegionsTable::OtherRegionsTable(HeapRegion* hr, Mutex* m) : 262 _g1h(G1CollectedHeap::heap()), 263 _hr(hr), _m(m), 264 _coarse_map(G1CollectedHeap::heap()->max_regions(), mtGC), 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 298void 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 325void 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 358void 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((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 < sprt_entry->num_valid_cards(); i++) { 427 CardIdx_t c = sprt_entry->card(i); 428 prt->add_card(c); 429 } 430 // Now we can delete the sparse entry. 431 bool res = _sparse_table.delete_entry(from_hrm_ind); 432 assert(res, "It should have been there."); 433 } 434 } 435 assert(prt != NULL && prt->hr() == from_hr, "consequence"); 436 } 437 // Note that we can't assert "prt->hr() == from_hr", because of the 438 // possibility of concurrent reuse. But see head comment of 439 // OtherRegionsTable for why this is OK. 440 assert(prt != NULL, "Inv"); 441 442 prt->add_reference(from); 443 assert(contains_reference(from), "We just added " PTR_FORMAT " to the PRT", p2i(from)); 444} 445 446PerRegionTable* 447OtherRegionsTable::find_region_table(size_t ind, HeapRegion* hr) const { 448 assert(ind < _max_fine_entries, "Preconditions."); 449 PerRegionTable* prt = _fine_grain_regions[ind]; 450 while (prt != NULL && prt->hr() != hr) { 451 prt = prt->collision_list_next(); 452 } 453 // Loop postcondition is the method postcondition. 454 return prt; 455} 456 457jint OtherRegionsTable::_n_coarsenings = 0; 458 459PerRegionTable* OtherRegionsTable::delete_region_table() { 460 assert(_m->owned_by_self(), "Precondition"); 461 assert(_n_fine_entries == _max_fine_entries, "Precondition"); 462 PerRegionTable* max = NULL; 463 jint max_occ = 0; 464 PerRegionTable** max_prev = NULL; 465 size_t max_ind; 466 467 size_t i = _fine_eviction_start; 468 for (size_t k = 0; k < _fine_eviction_sample_size; k++) { 469 size_t ii = i; 470 // Make sure we get a non-NULL sample. 471 while (_fine_grain_regions[ii] == NULL) { 472 ii++; 473 if (ii == _max_fine_entries) ii = 0; 474 guarantee(ii != i, "We must find one."); 475 } 476 PerRegionTable** prev = &_fine_grain_regions[ii]; 477 PerRegionTable* cur = *prev; 478 while (cur != NULL) { 479 jint cur_occ = cur->occupied(); 480 if (max == NULL || cur_occ > max_occ) { 481 max = cur; 482 max_prev = prev; 483 max_ind = i; 484 max_occ = cur_occ; 485 } 486 prev = cur->collision_list_next_addr(); 487 cur = cur->collision_list_next(); 488 } 489 i = i + _fine_eviction_stride; 490 if (i >= _n_fine_entries) i = i - _n_fine_entries; 491 } 492 493 _fine_eviction_start++; 494 495 if (_fine_eviction_start >= _n_fine_entries) { 496 _fine_eviction_start -= _n_fine_entries; 497 } 498 499 guarantee(max != NULL, "Since _n_fine_entries > 0"); 500 guarantee(max_prev != NULL, "Since max != NULL."); 501 502 // Set the corresponding coarse bit. 503 size_t max_hrm_index = (size_t) max->hr()->hrm_index(); 504 if (!_coarse_map.at(max_hrm_index)) { 505 _coarse_map.at_put(max_hrm_index, true); 506 _n_coarse_entries++; 507 } 508 509 // Unsplice. 510 *max_prev = max->collision_list_next(); 511 Atomic::inc(&_n_coarsenings); 512 _n_fine_entries--; 513 return max; 514} 515 516void OtherRegionsTable::scrub(G1CardLiveData* live_data) { 517 // First eliminated garbage regions from the coarse map. 518 log_develop_trace(gc, remset, scrub)("Scrubbing region %u:", _hr->hrm_index()); 519 520 log_develop_trace(gc, remset, scrub)(" Coarse map: before = " SIZE_FORMAT "...", _n_coarse_entries); 521 if (_n_coarse_entries > 0) { 522 live_data->remove_nonlive_regions(&_coarse_map); 523 _n_coarse_entries = _coarse_map.count_one_bits(); 524 } 525 log_develop_trace(gc, remset, scrub)(" after = " SIZE_FORMAT ".", _n_coarse_entries); 526 527 // Now do the fine-grained maps. 528 for (size_t i = 0; i < _max_fine_entries; i++) { 529 PerRegionTable* cur = _fine_grain_regions[i]; 530 PerRegionTable** prev = &_fine_grain_regions[i]; 531 while (cur != NULL) { 532 PerRegionTable* nxt = cur->collision_list_next(); 533 // If the entire region is dead, eliminate. 534 log_develop_trace(gc, remset, scrub)(" For other region %u:", cur->hr()->hrm_index()); 535 if (!live_data->is_region_live(cur->hr()->hrm_index())) { 536 *prev = nxt; 537 cur->set_collision_list_next(NULL); 538 _n_fine_entries--; 539 log_develop_trace(gc, remset, scrub)(" deleted via region map."); 540 unlink_from_all(cur); 541 PerRegionTable::free(cur); 542 } else { 543 // Do fine-grain elimination. 544 log_develop_trace(gc, remset, scrub)(" occ: before = %4d.", cur->occupied()); 545 cur->scrub(live_data); 546 log_develop_trace(gc, remset, scrub)(" after = %4d.", cur->occupied()); 547 // Did that empty the table completely? 548 if (cur->occupied() == 0) { 549 *prev = nxt; 550 cur->set_collision_list_next(NULL); 551 _n_fine_entries--; 552 unlink_from_all(cur); 553 PerRegionTable::free(cur); 554 } else { 555 prev = cur->collision_list_next_addr(); 556 } 557 } 558 cur = nxt; 559 } 560 } 561 // Since we may have deleted a from_card_cache entry from the RS, clear 562 // the FCC. 563 clear_fcc(); 564} 565 566bool OtherRegionsTable::occupancy_less_or_equal_than(size_t limit) const { 567 if (limit <= (size_t)G1RSetSparseRegionEntries) { 568 return occ_coarse() == 0 && _first_all_fine_prts == NULL && occ_sparse() <= limit; 569 } else { 570 // Current uses of this method may only use values less than G1RSetSparseRegionEntries 571 // for the limit. The solution, comparing against occupied() would be too slow 572 // at this time. 573 Unimplemented(); 574 return false; 575 } 576} 577 578bool OtherRegionsTable::is_empty() const { 579 return occ_sparse() == 0 && occ_coarse() == 0 && _first_all_fine_prts == NULL; 580} 581 582size_t OtherRegionsTable::occupied() const { 583 size_t sum = occ_fine(); 584 sum += occ_sparse(); 585 sum += occ_coarse(); 586 return sum; 587} 588 589size_t OtherRegionsTable::occ_fine() const { 590 size_t sum = 0; 591 592 size_t num = 0; 593 PerRegionTable * cur = _first_all_fine_prts; 594 while (cur != NULL) { 595 sum += cur->occupied(); 596 cur = cur->next(); 597 num++; 598 } 599 guarantee(num == _n_fine_entries, "just checking"); 600 return sum; 601} 602 603size_t OtherRegionsTable::occ_coarse() const { 604 return (_n_coarse_entries * HeapRegion::CardsPerRegion); 605} 606 607size_t OtherRegionsTable::occ_sparse() const { 608 return _sparse_table.occupied(); 609} 610 611size_t OtherRegionsTable::mem_size() const { 612 size_t sum = 0; 613 // all PRTs are of the same size so it is sufficient to query only one of them. 614 if (_first_all_fine_prts != NULL) { 615 assert(_last_all_fine_prts != NULL && 616 _first_all_fine_prts->mem_size() == _last_all_fine_prts->mem_size(), "check that mem_size() is constant"); 617 sum += _first_all_fine_prts->mem_size() * _n_fine_entries; 618 } 619 sum += (sizeof(PerRegionTable*) * _max_fine_entries); 620 sum += (_coarse_map.size_in_words() * HeapWordSize); 621 sum += (_sparse_table.mem_size()); 622 sum += sizeof(OtherRegionsTable) - sizeof(_sparse_table); // Avoid double counting above. 623 return sum; 624} 625 626size_t OtherRegionsTable::static_mem_size() { 627 return G1FromCardCache::static_mem_size(); 628} 629 630size_t OtherRegionsTable::fl_mem_size() { 631 return PerRegionTable::fl_mem_size(); 632} 633 634void OtherRegionsTable::clear_fcc() { 635 G1FromCardCache::clear(_hr->hrm_index()); 636} 637 638void OtherRegionsTable::clear() { 639 // if there are no entries, skip this step 640 if (_first_all_fine_prts != NULL) { 641 guarantee(_first_all_fine_prts != NULL && _last_all_fine_prts != NULL, "just checking"); 642 PerRegionTable::bulk_free(_first_all_fine_prts, _last_all_fine_prts); 643 memset(_fine_grain_regions, 0, _max_fine_entries * sizeof(_fine_grain_regions[0])); 644 } else { 645 guarantee(_first_all_fine_prts == NULL && _last_all_fine_prts == NULL, "just checking"); 646 } 647 648 _first_all_fine_prts = _last_all_fine_prts = NULL; 649 _sparse_table.clear(); 650 if (_n_coarse_entries > 0) { 651 _coarse_map.clear(); 652 } 653 _n_fine_entries = 0; 654 _n_coarse_entries = 0; 655 656 clear_fcc(); 657} 658 659bool 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 665bool 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((size_t)card_index < HeapRegion::CardsPerRegion, 684 "Must be in range."); 685 return _sparse_table.contains_card(hr_ind, card_index); 686 } 687} 688 689void 690OtherRegionsTable::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 691 _sparse_table.do_cleanup_work(hrrs_cleanup_task); 692} 693 694HeapRegionRemSet::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(), 699 _other_regions(hr, &_m) { 700} 701 702void 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 716void HeapRegionRemSet::cleanup() { 717 SparsePRT::cleanup_all(); 718} 719 720void HeapRegionRemSet::clear() { 721 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag); 722 clear_locked(); 723} 724 725void HeapRegionRemSet::clear_locked() { 726 _code_roots.clear(); 727 _other_regions.clear(); 728 assert(occupied_locked() == 0, "Should be clear."); 729} 730 731void HeapRegionRemSet::scrub(G1CardLiveData* live_data) { 732 _other_regions.scrub(live_data); 733} 734 735// Code roots support 736// 737// The code root set is protected by two separate locking schemes 738// When at safepoint the per-hrrs lock must be held during modifications 739// except when doing a full gc. 740// When not at safepoint the CodeCache_lock must be held during modifications. 741// When concurrent readers access the contains() function 742// (during the evacuation phase) no removals are allowed. 743 744void HeapRegionRemSet::add_strong_code_root(nmethod* nm) { 745 assert(nm != NULL, "sanity"); 746 assert((!CodeCache_lock->owned_by_self() || SafepointSynchronize::is_at_safepoint()), 747 "should call add_strong_code_root_locked instead. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s", 748 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint())); 749 // Optimistic unlocked contains-check 750 if (!_code_roots.contains(nm)) { 751 MutexLockerEx ml(&_m, Mutex::_no_safepoint_check_flag); 752 add_strong_code_root_locked(nm); 753 } 754} 755 756void HeapRegionRemSet::add_strong_code_root_locked(nmethod* nm) { 757 assert(nm != NULL, "sanity"); 758 assert((CodeCache_lock->owned_by_self() || 759 (SafepointSynchronize::is_at_safepoint() && 760 (_m.owned_by_self() || Thread::current()->is_VM_thread()))), 761 "not safely locked. CodeCache_lock->owned_by_self(): %s, is_at_safepoint(): %s, _m.owned_by_self(): %s, Thread::current()->is_VM_thread(): %s", 762 BOOL_TO_STR(CodeCache_lock->owned_by_self()), BOOL_TO_STR(SafepointSynchronize::is_at_safepoint()), 763 BOOL_TO_STR(_m.owned_by_self()), BOOL_TO_STR(Thread::current()->is_VM_thread())); 764 _code_roots.add(nm); 765} 766 767void HeapRegionRemSet::remove_strong_code_root(nmethod* nm) { 768 assert(nm != NULL, "sanity"); 769 assert_locked_or_safepoint(CodeCache_lock); 770 771 MutexLockerEx ml(CodeCache_lock->owned_by_self() ? NULL : &_m, Mutex::_no_safepoint_check_flag); 772 _code_roots.remove(nm); 773 774 // Check that there were no duplicates 775 guarantee(!_code_roots.contains(nm), "duplicate entry found"); 776} 777 778void HeapRegionRemSet::strong_code_roots_do(CodeBlobClosure* blk) const { 779 _code_roots.nmethods_do(blk); 780} 781 782void HeapRegionRemSet::clean_strong_code_roots(HeapRegion* hr) { 783 _code_roots.clean(hr); 784} 785 786size_t HeapRegionRemSet::strong_code_roots_mem_size() { 787 return _code_roots.mem_size(); 788} 789 790HeapRegionRemSetIterator:: HeapRegionRemSetIterator(HeapRegionRemSet* hrrs) : 791 _hrrs(hrrs), 792 _g1h(G1CollectedHeap::heap()), 793 _coarse_map(&hrrs->_other_regions._coarse_map), 794 _bot(hrrs->_bot), 795 _is(Sparse), 796 // Set these values so that we increment to the first region. 797 _coarse_cur_region_index(-1), 798 _coarse_cur_region_cur_card(HeapRegion::CardsPerRegion-1), 799 _cur_card_in_prt(HeapRegion::CardsPerRegion), 800 _fine_cur_prt(NULL), 801 _n_yielded_coarse(0), 802 _n_yielded_fine(0), 803 _n_yielded_sparse(0), 804 _sparse_iter(&hrrs->_other_regions._sparse_table) {} 805 806bool HeapRegionRemSetIterator::coarse_has_next(size_t& card_index) { 807 if (_hrrs->_other_regions._n_coarse_entries == 0) return false; 808 // Go to the next card. 809 _coarse_cur_region_cur_card++; 810 // Was the last the last card in the current region? 811 if (_coarse_cur_region_cur_card == HeapRegion::CardsPerRegion) { 812 // Yes: find the next region. This may leave _coarse_cur_region_index 813 // Set to the last index, in which case there are no more coarse 814 // regions. 815 _coarse_cur_region_index = 816 (int) _coarse_map->get_next_one_offset(_coarse_cur_region_index + 1); 817 if ((size_t)_coarse_cur_region_index < _coarse_map->size()) { 818 _coarse_cur_region_cur_card = 0; 819 HeapWord* r_bot = 820 _g1h->region_at((uint) _coarse_cur_region_index)->bottom(); 821 _cur_region_card_offset = _bot->index_for(r_bot); 822 } else { 823 return false; 824 } 825 } 826 // If we didn't return false above, then we can yield a card. 827 card_index = _cur_region_card_offset + _coarse_cur_region_cur_card; 828 return true; 829} 830 831bool HeapRegionRemSetIterator::fine_has_next(size_t& card_index) { 832 if (fine_has_next()) { 833 _cur_card_in_prt = 834 _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 835 } 836 if (_cur_card_in_prt == HeapRegion::CardsPerRegion) { 837 // _fine_cur_prt may still be NULL in case if there are not PRTs at all for 838 // the remembered set. 839 if (_fine_cur_prt == NULL || _fine_cur_prt->next() == NULL) { 840 return false; 841 } 842 PerRegionTable* next_prt = _fine_cur_prt->next(); 843 switch_to_prt(next_prt); 844 _cur_card_in_prt = _fine_cur_prt->_bm.get_next_one_offset(_cur_card_in_prt + 1); 845 } 846 847 card_index = _cur_region_card_offset + _cur_card_in_prt; 848 guarantee(_cur_card_in_prt < HeapRegion::CardsPerRegion, 849 "Card index " SIZE_FORMAT " must be within the region", _cur_card_in_prt); 850 return true; 851} 852 853bool HeapRegionRemSetIterator::fine_has_next() { 854 return _cur_card_in_prt != HeapRegion::CardsPerRegion; 855} 856 857void HeapRegionRemSetIterator::switch_to_prt(PerRegionTable* prt) { 858 assert(prt != NULL, "Cannot switch to NULL prt"); 859 _fine_cur_prt = prt; 860 861 HeapWord* r_bot = _fine_cur_prt->hr()->bottom(); 862 _cur_region_card_offset = _bot->index_for(r_bot); 863 864 // The bitmap scan for the PRT always scans from _cur_region_cur_card + 1. 865 // To avoid special-casing this start case, and not miss the first bitmap 866 // entry, initialize _cur_region_cur_card with -1 instead of 0. 867 _cur_card_in_prt = (size_t)-1; 868} 869 870bool HeapRegionRemSetIterator::has_next(size_t& card_index) { 871 switch (_is) { 872 case Sparse: { 873 if (_sparse_iter.has_next(card_index)) { 874 _n_yielded_sparse++; 875 return true; 876 } 877 // Otherwise, deliberate fall-through 878 _is = Fine; 879 PerRegionTable* initial_fine_prt = _hrrs->_other_regions._first_all_fine_prts; 880 if (initial_fine_prt != NULL) { 881 switch_to_prt(_hrrs->_other_regions._first_all_fine_prts); 882 } 883 } 884 case Fine: 885 if (fine_has_next(card_index)) { 886 _n_yielded_fine++; 887 return true; 888 } 889 // Otherwise, deliberate fall-through 890 _is = Coarse; 891 case Coarse: 892 if (coarse_has_next(card_index)) { 893 _n_yielded_coarse++; 894 return true; 895 } 896 // Otherwise... 897 break; 898 } 899 return false; 900} 901 902void HeapRegionRemSet::reset_for_cleanup_tasks() { 903 SparsePRT::reset_for_cleanup_tasks(); 904} 905 906void HeapRegionRemSet::do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task) { 907 _other_regions.do_cleanup_work(hrrs_cleanup_task); 908} 909 910void 911HeapRegionRemSet::finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task) { 912 SparsePRT::finish_cleanup_task(hrrs_cleanup_task); 913} 914 915#ifndef PRODUCT 916void HeapRegionRemSet::test() { 917 os::sleep(Thread::current(), (jlong)5000, false); 918 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 919 920 // Run with "-XX:G1LogRSetRegionEntries=2", so that 1 and 5 end up in same 921 // hash bucket. 922 HeapRegion* hr0 = g1h->region_at(0); 923 HeapRegion* hr1 = g1h->region_at(1); 924 HeapRegion* hr2 = g1h->region_at(5); 925 HeapRegion* hr3 = g1h->region_at(6); 926 HeapRegion* hr4 = g1h->region_at(7); 927 HeapRegion* hr5 = g1h->region_at(8); 928 929 HeapWord* hr1_start = hr1->bottom(); 930 HeapWord* hr1_mid = hr1_start + HeapRegion::GrainWords/2; 931 HeapWord* hr1_last = hr1->end() - 1; 932 933 HeapWord* hr2_start = hr2->bottom(); 934 HeapWord* hr2_mid = hr2_start + HeapRegion::GrainWords/2; 935 HeapWord* hr2_last = hr2->end() - 1; 936 937 HeapWord* hr3_start = hr3->bottom(); 938 HeapWord* hr3_mid = hr3_start + HeapRegion::GrainWords/2; 939 HeapWord* hr3_last = hr3->end() - 1; 940 941 HeapRegionRemSet* hrrs = hr0->rem_set(); 942 943 // Make three references from region 0x101... 944 hrrs->add_reference((OopOrNarrowOopStar)hr1_start); 945 hrrs->add_reference((OopOrNarrowOopStar)hr1_mid); 946 hrrs->add_reference((OopOrNarrowOopStar)hr1_last); 947 948 hrrs->add_reference((OopOrNarrowOopStar)hr2_start); 949 hrrs->add_reference((OopOrNarrowOopStar)hr2_mid); 950 hrrs->add_reference((OopOrNarrowOopStar)hr2_last); 951 952 hrrs->add_reference((OopOrNarrowOopStar)hr3_start); 953 hrrs->add_reference((OopOrNarrowOopStar)hr3_mid); 954 hrrs->add_reference((OopOrNarrowOopStar)hr3_last); 955 956 // Now cause a coarsening. 957 hrrs->add_reference((OopOrNarrowOopStar)hr4->bottom()); 958 hrrs->add_reference((OopOrNarrowOopStar)hr5->bottom()); 959 960 // Now, does iteration yield these three? 961 HeapRegionRemSetIterator iter(hrrs); 962 size_t sum = 0; 963 size_t card_index; 964 while (iter.has_next(card_index)) { 965 HeapWord* card_start = 966 G1CollectedHeap::heap()->bot()->address_for_index(card_index); 967 tty->print_cr(" Card " PTR_FORMAT ".", p2i(card_start)); 968 sum++; 969 } 970 guarantee(sum == 11 - 3 + 2048, "Failure"); 971 guarantee(sum == hrrs->occupied(), "Failure"); 972} 973#endif 974