1 /* 2 * Copyright (c) 2001, 2019, 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/g1Arguments.hpp" 27 #include "gc/g1/g1CollectedHeap.inline.hpp" 28 #include "gc/g1/g1ConcurrentRefine.hpp" 29 #include "gc/g1/g1NUMAStats.hpp" 30 #include "gc/g1/heapRegion.hpp" 31 #include "gc/g1/heapRegionManager.inline.hpp" 32 #include "gc/g1/heapRegionSet.inline.hpp" 33 #include "gc/g1/heterogeneousHeapRegionManager.hpp" 34 #include "logging/logStream.hpp" 35 #include "memory/allocation.hpp" 36 #include "utilities/bitMap.inline.hpp" 37 38 class MasterFreeRegionListChecker : public HeapRegionSetChecker { 39 public: 40 void check_mt_safety() { 41 // Master Free List MT safety protocol: 42 // (a) If we're at a safepoint, operations on the master free list 43 // should be invoked by either the VM thread (which will serialize 44 // them) or by the GC workers while holding the 45 // FreeList_lock. 46 // (b) If we're not at a safepoint, operations on the master free 47 // list should be invoked while holding the Heap_lock. 48 49 if (SafepointSynchronize::is_at_safepoint()) { 50 guarantee(Thread::current()->is_VM_thread() || 51 FreeList_lock->owned_by_self(), "master free list MT safety protocol at a safepoint"); 52 } else { 53 guarantee(Heap_lock->owned_by_self(), "master free list MT safety protocol outside a safepoint"); 54 } 55 } 56 bool is_correct_type(HeapRegion* hr) { return hr->is_free(); } 57 const char* get_description() { return "Free Regions"; } 58 }; 59 60 HeapRegionManager::HeapRegionManager() : 61 _bot_mapper(NULL), 62 _cardtable_mapper(NULL), 63 _card_counts_mapper(NULL), 64 _available_map(mtGC), 65 _num_committed(0), 66 _allocated_heapregions_length(0), 67 _regions(), _heap_mapper(NULL), 68 _prev_bitmap_mapper(NULL), 69 _next_bitmap_mapper(NULL), 70 _free_list("Free list", new MasterFreeRegionListChecker()) 71 { } 72 73 HeapRegionManager* HeapRegionManager::create_manager(G1CollectedHeap* heap) { 74 if (G1Arguments::is_heterogeneous_heap()) { 75 return new HeterogeneousHeapRegionManager((uint)(G1Arguments::heap_max_size_bytes() / HeapRegion::GrainBytes) /*heap size as num of regions*/); 76 } 77 return new HeapRegionManager(); 78 } 79 80 void HeapRegionManager::initialize(G1RegionToSpaceMapper* heap_storage, 81 G1RegionToSpaceMapper* prev_bitmap, 82 G1RegionToSpaceMapper* next_bitmap, 83 G1RegionToSpaceMapper* bot, 84 G1RegionToSpaceMapper* cardtable, 85 G1RegionToSpaceMapper* card_counts) { 86 _allocated_heapregions_length = 0; 87 88 _heap_mapper = heap_storage; 89 90 _prev_bitmap_mapper = prev_bitmap; 91 _next_bitmap_mapper = next_bitmap; 92 93 _bot_mapper = bot; 94 _cardtable_mapper = cardtable; 95 96 _card_counts_mapper = card_counts; 97 98 MemRegion reserved = heap_storage->reserved(); 99 _regions.initialize(reserved.start(), reserved.end(), HeapRegion::GrainBytes); 100 101 _available_map.initialize(_regions.length()); 102 } 103 104 bool HeapRegionManager::is_available(uint region) const { 105 return _available_map.at(region); 106 } 107 108 HeapRegion* HeapRegionManager::allocate_free_region(HeapRegionType type, uint requested_node_index) { 109 HeapRegion* hr = NULL; 110 bool from_head = !type.is_young(); 111 G1NUMA* numa = G1NUMA::numa(); 112 113 if (requested_node_index != G1NUMA::AnyNodeIndex && numa->is_enabled()) { 114 // Try to allocate with requested node index. 115 hr = _free_list.remove_region_with_node_index(from_head, requested_node_index); 116 } 117 118 if (hr == NULL) { 119 // If there's a single active node or we did not get a region from our requested node, 120 // try without requested node index. 121 hr = _free_list.remove_region(from_head); 122 } 123 124 if (hr != NULL) { 125 assert(hr->next() == NULL, "Single region should not have next"); 126 assert(is_available(hr->hrm_index()), "Must be committed"); 127 128 if (numa->is_enabled() && hr->node_index() < numa->num_active_nodes()) { 129 numa->update_statistics(G1NUMAStats::NewRegionAlloc, requested_node_index, hr->node_index()); 130 } 131 } 132 133 return hr; 134 } 135 136 #ifdef ASSERT 137 bool HeapRegionManager::is_free(HeapRegion* hr) const { 138 return _free_list.contains(hr); 139 } 140 #endif 141 142 HeapRegion* HeapRegionManager::new_heap_region(uint hrm_index) { 143 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 144 HeapWord* bottom = g1h->bottom_addr_for_region(hrm_index); 145 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 146 assert(reserved().contains(mr), "invariant"); 147 return g1h->new_heap_region(hrm_index, mr); 148 } 149 150 void HeapRegionManager::commit_regions(uint index, size_t num_regions, WorkGang* pretouch_gang) { 151 guarantee(num_regions > 0, "Must commit more than zero regions"); 152 guarantee(_num_committed + num_regions <= max_length(), "Cannot commit more than the maximum amount of regions"); 153 154 _num_committed += (uint)num_regions; 155 156 _heap_mapper->commit_regions(index, num_regions, pretouch_gang); 157 158 // Also commit auxiliary data 159 _prev_bitmap_mapper->commit_regions(index, num_regions, pretouch_gang); 160 _next_bitmap_mapper->commit_regions(index, num_regions, pretouch_gang); 161 162 _bot_mapper->commit_regions(index, num_regions, pretouch_gang); 163 _cardtable_mapper->commit_regions(index, num_regions, pretouch_gang); 164 165 _card_counts_mapper->commit_regions(index, num_regions, pretouch_gang); 166 } 167 168 void HeapRegionManager::uncommit_regions(uint start, size_t num_regions) { 169 guarantee(num_regions >= 1, "Need to specify at least one region to uncommit, tried to uncommit zero regions at %u", start); 170 guarantee(_num_committed >= num_regions, "pre-condition"); 171 172 // Reset node index to distinguish with committed regions. 173 for (uint i = start; i < start + num_regions; i++) { 174 at(i)->set_node_index(G1NUMA::UnknownNodeIndex); 175 } 176 177 // Print before uncommitting. 178 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 179 for (uint i = start; i < start + num_regions; i++) { 180 HeapRegion* hr = at(i); 181 G1CollectedHeap::heap()->hr_printer()->uncommit(hr); 182 } 183 } 184 185 _num_committed -= (uint)num_regions; 186 187 _available_map.par_clear_range(start, start + num_regions, BitMap::unknown_range); 188 _heap_mapper->uncommit_regions(start, num_regions); 189 190 // Also uncommit auxiliary data 191 _prev_bitmap_mapper->uncommit_regions(start, num_regions); 192 _next_bitmap_mapper->uncommit_regions(start, num_regions); 193 194 _bot_mapper->uncommit_regions(start, num_regions); 195 _cardtable_mapper->uncommit_regions(start, num_regions); 196 197 _card_counts_mapper->uncommit_regions(start, num_regions); 198 } 199 200 void HeapRegionManager::make_regions_available(uint start, uint num_regions, WorkGang* pretouch_gang) { 201 guarantee(num_regions > 0, "No point in calling this for zero regions"); 202 commit_regions(start, num_regions, pretouch_gang); 203 for (uint i = start; i < start + num_regions; i++) { 204 if (_regions.get_by_index(i) == NULL) { 205 HeapRegion* new_hr = new_heap_region(i); 206 OrderAccess::storestore(); 207 _regions.set_by_index(i, new_hr); 208 _allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1); 209 } 210 } 211 212 _available_map.par_set_range(start, start + num_regions, BitMap::unknown_range); 213 214 for (uint i = start; i < start + num_regions; i++) { 215 assert(is_available(i), "Just made region %u available but is apparently not.", i); 216 HeapRegion* hr = at(i); 217 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 218 G1CollectedHeap::heap()->hr_printer()->commit(hr); 219 } 220 HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i); 221 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 222 223 hr->initialize(mr); 224 hr->set_node_index(G1NUMA::numa()->index_for_region(hr)); 225 insert_into_free_list(at(i)); 226 } 227 } 228 229 MemoryUsage HeapRegionManager::get_auxiliary_data_memory_usage() const { 230 size_t used_sz = 231 _prev_bitmap_mapper->committed_size() + 232 _next_bitmap_mapper->committed_size() + 233 _bot_mapper->committed_size() + 234 _cardtable_mapper->committed_size() + 235 _card_counts_mapper->committed_size(); 236 237 size_t committed_sz = 238 _prev_bitmap_mapper->reserved_size() + 239 _next_bitmap_mapper->reserved_size() + 240 _bot_mapper->reserved_size() + 241 _cardtable_mapper->reserved_size() + 242 _card_counts_mapper->reserved_size(); 243 244 return MemoryUsage(0, used_sz, committed_sz, committed_sz); 245 } 246 247 uint HeapRegionManager::expand_by(uint num_regions, WorkGang* pretouch_workers) { 248 return expand_at(0, num_regions, pretouch_workers); 249 } 250 251 uint HeapRegionManager::expand_at(uint start, uint num_regions, WorkGang* pretouch_workers) { 252 if (num_regions == 0) { 253 return 0; 254 } 255 256 uint cur = start; 257 uint idx_last_found = 0; 258 uint num_last_found = 0; 259 260 uint expanded = 0; 261 262 while (expanded < num_regions && 263 (num_last_found = find_unavailable_from_idx(cur, &idx_last_found)) > 0) { 264 uint to_expand = MIN2(num_regions - expanded, num_last_found); 265 make_regions_available(idx_last_found, to_expand, pretouch_workers); 266 expanded += to_expand; 267 cur = idx_last_found + num_last_found + 1; 268 } 269 270 verify_optional(); 271 return expanded; 272 } 273 274 uint HeapRegionManager::expand_on_preferred_node(uint preferred_index) { 275 uint expand_candidate = UINT_MAX; 276 for (uint i = 0; i < max_length(); i++) { 277 if (is_available(i)) { 278 // Already in use continue 279 continue; 280 } 281 // Always save the candidate so we can expand later on. 282 expand_candidate = i; 283 if (is_on_preferred_index(expand_candidate, preferred_index)) { 284 // We have found a candidate on the preffered node, break. 285 break; 286 } 287 } 288 289 if (expand_candidate == UINT_MAX) { 290 // No regions left, expand failed. 291 return 0; 292 } 293 294 make_regions_available(expand_candidate, 1, NULL); 295 return 1; 296 } 297 298 bool HeapRegionManager::is_on_preferred_index(uint region_index, uint preferred_node_index) { 299 uint region_node_index = G1NUMA::numa()->preferred_node_index_for_index(region_index); 300 return region_node_index == preferred_node_index; 301 } 302 303 uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) { 304 uint found = 0; 305 size_t length_found = 0; 306 uint cur = 0; 307 308 while (length_found < num && cur < max_length()) { 309 HeapRegion* hr = _regions.get_by_index(cur); 310 if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) { 311 // This region is a potential candidate for allocation into. 312 length_found++; 313 } else { 314 // This region is not a candidate. The next region is the next possible one. 315 found = cur + 1; 316 length_found = 0; 317 } 318 cur++; 319 } 320 321 if (length_found == num) { 322 for (uint i = found; i < (found + num); i++) { 323 HeapRegion* hr = _regions.get_by_index(i); 324 // sanity check 325 guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()), 326 "Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT 327 " that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr)); 328 } 329 return found; 330 } else { 331 return G1_NO_HRM_INDEX; 332 } 333 } 334 335 HeapRegion* HeapRegionManager::next_region_in_heap(const HeapRegion* r) const { 336 guarantee(r != NULL, "Start region must be a valid region"); 337 guarantee(is_available(r->hrm_index()), "Trying to iterate starting from region %u which is not in the heap", r->hrm_index()); 338 for (uint i = r->hrm_index() + 1; i < _allocated_heapregions_length; i++) { 339 HeapRegion* hr = _regions.get_by_index(i); 340 if (is_available(i)) { 341 return hr; 342 } 343 } 344 return NULL; 345 } 346 347 void HeapRegionManager::iterate(HeapRegionClosure* blk) const { 348 uint len = max_length(); 349 350 for (uint i = 0; i < len; i++) { 351 if (!is_available(i)) { 352 continue; 353 } 354 guarantee(at(i) != NULL, "Tried to access region %u that has a NULL HeapRegion*", i); 355 bool res = blk->do_heap_region(at(i)); 356 if (res) { 357 blk->set_incomplete(); 358 return; 359 } 360 } 361 } 362 363 uint HeapRegionManager::find_unavailable_from_idx(uint start_idx, uint* res_idx) const { 364 guarantee(res_idx != NULL, "checking"); 365 guarantee(start_idx <= (max_length() + 1), "checking"); 366 367 uint num_regions = 0; 368 369 uint cur = start_idx; 370 while (cur < max_length() && is_available(cur)) { 371 cur++; 372 } 373 if (cur == max_length()) { 374 return num_regions; 375 } 376 *res_idx = cur; 377 while (cur < max_length() && !is_available(cur)) { 378 cur++; 379 } 380 num_regions = cur - *res_idx; 381 #ifdef ASSERT 382 for (uint i = *res_idx; i < (*res_idx + num_regions); i++) { 383 assert(!is_available(i), "just checking"); 384 } 385 assert(cur == max_length() || num_regions == 0 || is_available(cur), 386 "The region at the current position %u must be available or at the end of the heap.", cur); 387 #endif 388 return num_regions; 389 } 390 391 uint HeapRegionManager::find_highest_free(bool* expanded) { 392 // Loop downwards from the highest region index, looking for an 393 // entry which is either free or not yet committed. If not yet 394 // committed, expand_at that index. 395 uint curr = max_length() - 1; 396 while (true) { 397 HeapRegion *hr = _regions.get_by_index(curr); 398 if (hr == NULL || !is_available(curr)) { 399 uint res = expand_at(curr, 1, NULL); 400 if (res == 1) { 401 *expanded = true; 402 return curr; 403 } 404 } else { 405 if (hr->is_free()) { 406 *expanded = false; 407 return curr; 408 } 409 } 410 if (curr == 0) { 411 return G1_NO_HRM_INDEX; 412 } 413 curr--; 414 } 415 } 416 417 bool HeapRegionManager::allocate_containing_regions(MemRegion range, size_t* commit_count, WorkGang* pretouch_workers) { 418 size_t commits = 0; 419 uint start_index = (uint)_regions.get_index_by_address(range.start()); 420 uint last_index = (uint)_regions.get_index_by_address(range.last()); 421 422 // Ensure that each G1 region in the range is free, returning false if not. 423 // Commit those that are not yet available, and keep count. 424 for (uint curr_index = start_index; curr_index <= last_index; curr_index++) { 425 if (!is_available(curr_index)) { 426 commits++; 427 expand_at(curr_index, 1, pretouch_workers); 428 } 429 HeapRegion* curr_region = _regions.get_by_index(curr_index); 430 if (!curr_region->is_free()) { 431 return false; 432 } 433 } 434 435 allocate_free_regions_starting_at(start_index, (last_index - start_index) + 1); 436 *commit_count = commits; 437 return true; 438 } 439 440 void HeapRegionManager::par_iterate(HeapRegionClosure* blk, HeapRegionClaimer* hrclaimer, const uint start_index) const { 441 // Every worker will actually look at all regions, skipping over regions that 442 // are currently not committed. 443 // This also (potentially) iterates over regions newly allocated during GC. This 444 // is no problem except for some extra work. 445 const uint n_regions = hrclaimer->n_regions(); 446 for (uint count = 0; count < n_regions; count++) { 447 const uint index = (start_index + count) % n_regions; 448 assert(index < n_regions, "sanity"); 449 // Skip over unavailable regions 450 if (!is_available(index)) { 451 continue; 452 } 453 HeapRegion* r = _regions.get_by_index(index); 454 // We'll ignore regions already claimed. 455 // However, if the iteration is specified as concurrent, the values for 456 // is_starts_humongous and is_continues_humongous can not be trusted, 457 // and we should just blindly iterate over regions regardless of their 458 // humongous status. 459 if (hrclaimer->is_region_claimed(index)) { 460 continue; 461 } 462 // OK, try to claim it 463 if (!hrclaimer->claim_region(index)) { 464 continue; 465 } 466 bool res = blk->do_heap_region(r); 467 if (res) { 468 return; 469 } 470 } 471 } 472 473 uint HeapRegionManager::shrink_by(uint num_regions_to_remove) { 474 assert(length() > 0, "the region sequence should not be empty"); 475 assert(length() <= _allocated_heapregions_length, "invariant"); 476 assert(_allocated_heapregions_length > 0, "we should have at least one region committed"); 477 assert(num_regions_to_remove < length(), "We should never remove all regions"); 478 479 if (num_regions_to_remove == 0) { 480 return 0; 481 } 482 483 uint removed = 0; 484 uint cur = _allocated_heapregions_length - 1; 485 uint idx_last_found = 0; 486 uint num_last_found = 0; 487 488 while ((removed < num_regions_to_remove) && 489 (num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 0) { 490 uint to_remove = MIN2(num_regions_to_remove - removed, num_last_found); 491 492 shrink_at(idx_last_found + num_last_found - to_remove, to_remove); 493 494 cur = idx_last_found; 495 removed += to_remove; 496 } 497 498 verify_optional(); 499 500 return removed; 501 } 502 503 void HeapRegionManager::shrink_at(uint index, size_t num_regions) { 504 #ifdef ASSERT 505 for (uint i = index; i < (index + num_regions); i++) { 506 assert(is_available(i), "Expected available region at index %u", i); 507 assert(at(i)->is_empty(), "Expected empty region at index %u", i); 508 assert(at(i)->is_free(), "Expected free region at index %u", i); 509 } 510 #endif 511 uncommit_regions(index, num_regions); 512 } 513 514 uint HeapRegionManager::find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const { 515 guarantee(start_idx < _allocated_heapregions_length, "checking"); 516 guarantee(res_idx != NULL, "checking"); 517 518 uint num_regions_found = 0; 519 520 jlong cur = start_idx; 521 while (cur != -1 && !(is_available(cur) && at(cur)->is_empty())) { 522 cur--; 523 } 524 if (cur == -1) { 525 return num_regions_found; 526 } 527 jlong old_cur = cur; 528 // cur indexes the first empty region 529 while (cur != -1 && is_available(cur) && at(cur)->is_empty()) { 530 cur--; 531 } 532 *res_idx = cur + 1; 533 num_regions_found = old_cur - cur; 534 535 #ifdef ASSERT 536 for (uint i = *res_idx; i < (*res_idx + num_regions_found); i++) { 537 assert(at(i)->is_empty(), "just checking"); 538 } 539 #endif 540 return num_regions_found; 541 } 542 543 void HeapRegionManager::verify() { 544 guarantee(length() <= _allocated_heapregions_length, 545 "invariant: _length: %u _allocated_length: %u", 546 length(), _allocated_heapregions_length); 547 guarantee(_allocated_heapregions_length <= max_length(), 548 "invariant: _allocated_length: %u _max_length: %u", 549 _allocated_heapregions_length, max_length()); 550 551 bool prev_committed = true; 552 uint num_committed = 0; 553 HeapWord* prev_end = heap_bottom(); 554 for (uint i = 0; i < _allocated_heapregions_length; i++) { 555 if (!is_available(i)) { 556 prev_committed = false; 557 continue; 558 } 559 num_committed++; 560 HeapRegion* hr = _regions.get_by_index(i); 561 guarantee(hr != NULL, "invariant: i: %u", i); 562 guarantee(!prev_committed || hr->bottom() == prev_end, 563 "invariant i: %u " HR_FORMAT " prev_end: " PTR_FORMAT, 564 i, HR_FORMAT_PARAMS(hr), p2i(prev_end)); 565 guarantee(hr->hrm_index() == i, 566 "invariant: i: %u hrm_index(): %u", i, hr->hrm_index()); 567 // Asserts will fire if i is >= _length 568 HeapWord* addr = hr->bottom(); 569 guarantee(addr_to_region(addr) == hr, "sanity"); 570 // We cannot check whether the region is part of a particular set: at the time 571 // this method may be called, we have only completed allocation of the regions, 572 // but not put into a region set. 573 prev_committed = true; 574 prev_end = hr->end(); 575 } 576 for (uint i = _allocated_heapregions_length; i < max_length(); i++) { 577 guarantee(_regions.get_by_index(i) == NULL, "invariant i: %u", i); 578 } 579 580 guarantee(num_committed == _num_committed, "Found %u committed regions, but should be %u", num_committed, _num_committed); 581 _free_list.verify(); 582 } 583 584 #ifndef PRODUCT 585 void HeapRegionManager::verify_optional() { 586 verify(); 587 } 588 #endif // PRODUCT 589 590 HeapRegionClaimer::HeapRegionClaimer(uint n_workers) : 591 _n_workers(n_workers), _n_regions(G1CollectedHeap::heap()->_hrm->_allocated_heapregions_length), _claims(NULL) { 592 assert(n_workers > 0, "Need at least one worker."); 593 uint* new_claims = NEW_C_HEAP_ARRAY(uint, _n_regions, mtGC); 594 memset(new_claims, Unclaimed, sizeof(*_claims) * _n_regions); 595 _claims = new_claims; 596 } 597 598 HeapRegionClaimer::~HeapRegionClaimer() { 599 FREE_C_HEAP_ARRAY(uint, _claims); 600 } 601 602 uint HeapRegionClaimer::offset_for_worker(uint worker_id) const { 603 assert(worker_id < _n_workers, "Invalid worker_id."); 604 return _n_regions * worker_id / _n_workers; 605 } 606 607 bool HeapRegionClaimer::is_region_claimed(uint region_index) const { 608 assert(region_index < _n_regions, "Invalid index."); 609 return _claims[region_index] == Claimed; 610 } 611 612 bool HeapRegionClaimer::claim_region(uint region_index) { 613 assert(region_index < _n_regions, "Invalid index."); 614 uint old_val = Atomic::cmpxchg(Claimed, &_claims[region_index], Unclaimed); 615 return old_val == Unclaimed; 616 }