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/g1CollectedHeap.inline.hpp" 27 #include "gc/g1/g1ConcurrentRefine.hpp" 28 #include "gc/g1/heapRegion.hpp" 29 #include "gc/g1/heapRegionManager.inline.hpp" 30 #include "gc/g1/heapRegionSet.inline.hpp" 31 #include "memory/allocation.hpp" 32 33 void HeapRegionManager::initialize(G1RegionToSpaceMapper* heap_storage, 34 G1RegionToSpaceMapper* prev_bitmap, 35 G1RegionToSpaceMapper* next_bitmap, 36 G1RegionToSpaceMapper* bot, 37 G1RegionToSpaceMapper* cardtable, 38 G1RegionToSpaceMapper* card_counts) { 39 _allocated_heapregions_length = 0; 40 41 _heap_mapper = heap_storage; 42 43 _prev_bitmap_mapper = prev_bitmap; 44 _next_bitmap_mapper = next_bitmap; 45 46 _bot_mapper = bot; 47 _cardtable_mapper = cardtable; 48 49 _card_counts_mapper = card_counts; 50 51 MemRegion reserved = heap_storage->reserved(); 52 _regions.initialize(reserved.start(), reserved.end(), HeapRegion::GrainBytes); 53 54 _available_map.initialize(_regions.length()); 55 } 56 57 bool HeapRegionManager::is_available(uint region) const { 58 return _available_map.at(region); 59 } 60 61 #ifdef ASSERT 62 bool HeapRegionManager::is_free(HeapRegion* hr) const { 63 return _free_list.contains(hr); 64 } 65 #endif 66 67 HeapRegion* HeapRegionManager::new_heap_region(uint hrm_index) { 68 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 69 HeapWord* bottom = g1h->bottom_addr_for_region(hrm_index); 70 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 71 assert(reserved().contains(mr), "invariant"); 72 return g1h->new_heap_region(hrm_index, mr); 73 } 74 75 void HeapRegionManager::commit_regions(uint index, size_t num_regions, WorkGang* pretouch_gang) { 76 guarantee(num_regions > 0, "Must commit more than zero regions"); 77 guarantee(_num_committed + num_regions <= max_length(), "Cannot commit more than the maximum amount of regions"); 78 79 _num_committed += (uint)num_regions; 80 81 _heap_mapper->commit_regions(index, num_regions, pretouch_gang); 82 83 // Also commit auxiliary data 84 _prev_bitmap_mapper->commit_regions(index, num_regions, pretouch_gang); 85 _next_bitmap_mapper->commit_regions(index, num_regions, pretouch_gang); 86 87 _bot_mapper->commit_regions(index, num_regions, pretouch_gang); 88 _cardtable_mapper->commit_regions(index, num_regions, pretouch_gang); 89 90 _card_counts_mapper->commit_regions(index, num_regions, pretouch_gang); 91 } 92 93 void HeapRegionManager::uncommit_regions(uint start, size_t num_regions) { 94 guarantee(num_regions >= 1, "Need to specify at least one region to uncommit, tried to uncommit zero regions at %u", start); 95 guarantee(_num_committed >= num_regions, "pre-condition"); 96 97 // Print before uncommitting. 98 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 99 for (uint i = start; i < start + num_regions; i++) { 100 HeapRegion* hr = at(i); 101 G1CollectedHeap::heap()->hr_printer()->uncommit(hr); 102 } 103 } 104 105 _num_committed -= (uint)num_regions; 106 107 _available_map.par_clear_range(start, start + num_regions, BitMap::unknown_range); 108 _heap_mapper->uncommit_regions(start, num_regions); 109 110 // Also uncommit auxiliary data 111 _prev_bitmap_mapper->uncommit_regions(start, num_regions); 112 _next_bitmap_mapper->uncommit_regions(start, num_regions); 113 114 _bot_mapper->uncommit_regions(start, num_regions); 115 _cardtable_mapper->uncommit_regions(start, num_regions); 116 117 _card_counts_mapper->uncommit_regions(start, num_regions); 118 } 119 120 void HeapRegionManager::make_regions_available(uint start, uint num_regions, WorkGang* pretouch_gang) { 121 guarantee(num_regions > 0, "No point in calling this for zero regions"); 122 commit_regions(start, num_regions, pretouch_gang); 123 for (uint i = start; i < start + num_regions; i++) { 124 if (_regions.get_by_index(i) == NULL) { 125 HeapRegion* new_hr = new_heap_region(i); 126 OrderAccess::storestore(); 127 _regions.set_by_index(i, new_hr); 128 _allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1); 129 } 130 } 131 132 _available_map.par_set_range(start, start + num_regions, BitMap::unknown_range); 133 134 for (uint i = start; i < start + num_regions; i++) { 135 assert(is_available(i), "Just made region %u available but is apparently not.", i); 136 HeapRegion* hr = at(i); 137 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 138 G1CollectedHeap::heap()->hr_printer()->commit(hr); 139 } 140 HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i); 141 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 142 143 hr->initialize(mr); 144 insert_into_free_list(at(i)); 145 } 146 } 147 148 MemoryUsage HeapRegionManager::get_auxiliary_data_memory_usage() const { 149 size_t used_sz = 150 _prev_bitmap_mapper->committed_size() + 151 _next_bitmap_mapper->committed_size() + 152 _bot_mapper->committed_size() + 153 _cardtable_mapper->committed_size() + 154 _card_counts_mapper->committed_size(); 155 156 size_t committed_sz = 157 _prev_bitmap_mapper->reserved_size() + 158 _next_bitmap_mapper->reserved_size() + 159 _bot_mapper->reserved_size() + 160 _cardtable_mapper->reserved_size() + 161 _card_counts_mapper->reserved_size(); 162 163 return MemoryUsage(0, used_sz, committed_sz, committed_sz); 164 } 165 166 uint HeapRegionManager::expand_by(uint num_regions, WorkGang* pretouch_workers) { 167 return expand_at(0, num_regions, pretouch_workers); 168 } 169 170 uint HeapRegionManager::expand_at(uint start, uint num_regions, WorkGang* pretouch_workers) { 171 if (num_regions == 0) { 172 return 0; 173 } 174 175 uint cur = start; 176 uint idx_last_found = 0; 177 uint num_last_found = 0; 178 179 uint expanded = 0; 180 181 while (expanded < num_regions && 182 (num_last_found = find_unavailable_from_idx(cur, &idx_last_found)) > 0) { 183 uint to_expand = MIN2(num_regions - expanded, num_last_found); 184 make_regions_available(idx_last_found, to_expand, pretouch_workers); 185 expanded += to_expand; 186 cur = idx_last_found + num_last_found + 1; 187 } 188 189 verify_optional(); 190 return expanded; 191 } 192 193 uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) { 194 uint found = 0; 195 size_t length_found = 0; 196 uint cur = 0; 197 198 while (length_found < num && cur < max_length()) { 199 HeapRegion* hr = _regions.get_by_index(cur); 200 if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) { 201 // This region is a potential candidate for allocation into. 202 length_found++; 203 } else { 204 // This region is not a candidate. The next region is the next possible one. 205 found = cur + 1; 206 length_found = 0; 207 } 208 cur++; 209 } 210 211 if (length_found == num) { 212 for (uint i = found; i < (found + num); i++) { 213 HeapRegion* hr = _regions.get_by_index(i); 214 // sanity check 215 guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()), 216 "Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT 217 " that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr)); 218 } 219 return found; 220 } else { 221 return G1_NO_HRM_INDEX; 222 } 223 } 224 225 HeapRegion* HeapRegionManager::next_region_in_heap(const HeapRegion* r) const { 226 guarantee(r != NULL, "Start region must be a valid region"); 227 guarantee(is_available(r->hrm_index()), "Trying to iterate starting from region %u which is not in the heap", r->hrm_index()); 228 for (uint i = r->hrm_index() + 1; i < _allocated_heapregions_length; i++) { 229 HeapRegion* hr = _regions.get_by_index(i); 230 if (is_available(i)) { 231 return hr; 232 } 233 } 234 return NULL; 235 } 236 237 void HeapRegionManager::iterate(HeapRegionClosure* blk) const { 238 uint len = max_length(); 239 240 for (uint i = 0; i < len; i++) { 241 if (!is_available(i)) { 242 continue; 243 } 244 guarantee(at(i) != NULL, "Tried to access region %u that has a NULL HeapRegion*", i); 245 bool res = blk->doHeapRegion(at(i)); 246 if (res) { 247 blk->incomplete(); 248 return; 249 } 250 } 251 } 252 253 uint HeapRegionManager::find_unavailable_from_idx(uint start_idx, uint* res_idx) const { 254 guarantee(res_idx != NULL, "checking"); 255 guarantee(start_idx <= (max_length() + 1), "checking"); 256 257 uint num_regions = 0; 258 259 uint cur = start_idx; 260 while (cur < max_length() && is_available(cur)) { 261 cur++; 262 } 263 if (cur == max_length()) { 264 return num_regions; 265 } 266 *res_idx = cur; 267 while (cur < max_length() && !is_available(cur)) { 268 cur++; 269 } 270 num_regions = cur - *res_idx; 271 #ifdef ASSERT 272 for (uint i = *res_idx; i < (*res_idx + num_regions); i++) { 273 assert(!is_available(i), "just checking"); 274 } 275 assert(cur == max_length() || num_regions == 0 || is_available(cur), 276 "The region at the current position %u must be available or at the end of the heap.", cur); 277 #endif 278 return num_regions; 279 } 280 281 uint HeapRegionManager::find_highest_free(bool* expanded) { 282 // Loop downwards from the highest region index, looking for an 283 // entry which is either free or not yet committed. If not yet 284 // committed, expand_at that index. 285 uint curr = max_length() - 1; 286 while (true) { 287 HeapRegion *hr = _regions.get_by_index(curr); 288 if (hr == NULL) { 289 uint res = expand_at(curr, 1, NULL); 290 if (res == 1) { 291 *expanded = true; 292 return curr; 293 } 294 } else { 295 if (hr->is_free()) { 296 *expanded = false; 297 return curr; 298 } 299 } 300 if (curr == 0) { 301 return G1_NO_HRM_INDEX; 302 } 303 curr--; 304 } 305 } 306 307 bool HeapRegionManager::allocate_containing_regions(MemRegion range, size_t* commit_count, WorkGang* pretouch_workers) { 308 size_t commits = 0; 309 uint start_index = (uint)_regions.get_index_by_address(range.start()); 310 uint last_index = (uint)_regions.get_index_by_address(range.last()); 311 312 // Ensure that each G1 region in the range is free, returning false if not. 313 // Commit those that are not yet available, and keep count. 314 for (uint curr_index = start_index; curr_index <= last_index; curr_index++) { 315 if (!is_available(curr_index)) { 316 commits++; 317 expand_at(curr_index, 1, pretouch_workers); 318 } 319 HeapRegion* curr_region = _regions.get_by_index(curr_index); 320 if (!curr_region->is_free()) { 321 return false; 322 } 323 } 324 325 allocate_free_regions_starting_at(start_index, (last_index - start_index) + 1); 326 *commit_count = commits; 327 return true; 328 } 329 330 void HeapRegionManager::par_iterate(HeapRegionClosure* blk, HeapRegionClaimer* hrclaimer, const uint start_index) const { 331 // Every worker will actually look at all regions, skipping over regions that 332 // are currently not committed. 333 // This also (potentially) iterates over regions newly allocated during GC. This 334 // is no problem except for some extra work. 335 const uint n_regions = hrclaimer->n_regions(); 336 for (uint count = 0; count < n_regions; count++) { 337 const uint index = (start_index + count) % n_regions; 338 assert(index < n_regions, "sanity"); 339 // Skip over unavailable regions 340 if (!is_available(index)) { 341 continue; 342 } 343 HeapRegion* r = _regions.get_by_index(index); 344 // We'll ignore regions already claimed. 345 // However, if the iteration is specified as concurrent, the values for 346 // is_starts_humongous and is_continues_humongous can not be trusted, 347 // and we should just blindly iterate over regions regardless of their 348 // humongous status. 349 if (hrclaimer->is_region_claimed(index)) { 350 continue; 351 } 352 // OK, try to claim it 353 if (!hrclaimer->claim_region(index)) { 354 continue; 355 } 356 bool res = blk->doHeapRegion(r); 357 if (res) { 358 return; 359 } 360 } 361 } 362 363 uint HeapRegionManager::shrink_by(uint num_regions_to_remove) { 364 assert(length() > 0, "the region sequence should not be empty"); 365 assert(length() <= _allocated_heapregions_length, "invariant"); 366 assert(_allocated_heapregions_length > 0, "we should have at least one region committed"); 367 assert(num_regions_to_remove < length(), "We should never remove all regions"); 368 369 if (num_regions_to_remove == 0) { 370 return 0; 371 } 372 373 uint removed = 0; 374 uint cur = _allocated_heapregions_length - 1; 375 uint idx_last_found = 0; 376 uint num_last_found = 0; 377 378 while ((removed < num_regions_to_remove) && 379 (num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 0) { 380 uint to_remove = MIN2(num_regions_to_remove - removed, num_last_found); 381 382 shrink_at(idx_last_found + num_last_found - to_remove, to_remove); 383 384 cur = idx_last_found; 385 removed += to_remove; 386 } 387 388 verify_optional(); 389 390 return removed; 391 } 392 393 void HeapRegionManager::shrink_at(uint index, size_t num_regions) { 394 #ifdef ASSERT 395 for (uint i = index; i < (index + num_regions); i++) { 396 assert(is_available(i), "Expected available region at index %u", i); 397 assert(at(i)->is_empty(), "Expected empty region at index %u", i); 398 assert(at(i)->is_free(), "Expected free region at index %u", i); 399 } 400 #endif 401 uncommit_regions(index, num_regions); 402 } 403 404 uint HeapRegionManager::find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const { 405 guarantee(start_idx < _allocated_heapregions_length, "checking"); 406 guarantee(res_idx != NULL, "checking"); 407 408 uint num_regions_found = 0; 409 410 jlong cur = start_idx; 411 while (cur != -1 && !(is_available(cur) && at(cur)->is_empty())) { 412 cur--; 413 } 414 if (cur == -1) { 415 return num_regions_found; 416 } 417 jlong old_cur = cur; 418 // cur indexes the first empty region 419 while (cur != -1 && is_available(cur) && at(cur)->is_empty()) { 420 cur--; 421 } 422 *res_idx = cur + 1; 423 num_regions_found = old_cur - cur; 424 425 #ifdef ASSERT 426 for (uint i = *res_idx; i < (*res_idx + num_regions_found); i++) { 427 assert(at(i)->is_empty(), "just checking"); 428 } 429 #endif 430 return num_regions_found; 431 } 432 433 void HeapRegionManager::verify() { 434 guarantee(length() <= _allocated_heapregions_length, 435 "invariant: _length: %u _allocated_length: %u", 436 length(), _allocated_heapregions_length); 437 guarantee(_allocated_heapregions_length <= max_length(), 438 "invariant: _allocated_length: %u _max_length: %u", 439 _allocated_heapregions_length, max_length()); 440 441 bool prev_committed = true; 442 uint num_committed = 0; 443 HeapWord* prev_end = heap_bottom(); 444 for (uint i = 0; i < _allocated_heapregions_length; i++) { 445 if (!is_available(i)) { 446 prev_committed = false; 447 continue; 448 } 449 num_committed++; 450 HeapRegion* hr = _regions.get_by_index(i); 451 guarantee(hr != NULL, "invariant: i: %u", i); 452 guarantee(!prev_committed || hr->bottom() == prev_end, 453 "invariant i: %u " HR_FORMAT " prev_end: " PTR_FORMAT, 454 i, HR_FORMAT_PARAMS(hr), p2i(prev_end)); 455 guarantee(hr->hrm_index() == i, 456 "invariant: i: %u hrm_index(): %u", i, hr->hrm_index()); 457 // Asserts will fire if i is >= _length 458 HeapWord* addr = hr->bottom(); 459 guarantee(addr_to_region(addr) == hr, "sanity"); 460 // We cannot check whether the region is part of a particular set: at the time 461 // this method may be called, we have only completed allocation of the regions, 462 // but not put into a region set. 463 prev_committed = true; 464 prev_end = hr->end(); 465 } 466 for (uint i = _allocated_heapregions_length; i < max_length(); i++) { 467 guarantee(_regions.get_by_index(i) == NULL, "invariant i: %u", i); 468 } 469 470 guarantee(num_committed == _num_committed, "Found %u committed regions, but should be %u", num_committed, _num_committed); 471 _free_list.verify(); 472 } 473 474 #ifndef PRODUCT 475 void HeapRegionManager::verify_optional() { 476 verify(); 477 } 478 #endif // PRODUCT 479 480 HeapRegionClaimer::HeapRegionClaimer(uint n_workers) : 481 _n_workers(n_workers), _n_regions(G1CollectedHeap::heap()->_hrm._allocated_heapregions_length), _claims(NULL) { 482 assert(n_workers > 0, "Need at least one worker."); 483 uint* new_claims = NEW_C_HEAP_ARRAY(uint, _n_regions, mtGC); 484 memset(new_claims, Unclaimed, sizeof(*_claims) * _n_regions); 485 _claims = new_claims; 486 } 487 488 HeapRegionClaimer::~HeapRegionClaimer() { 489 if (_claims != NULL) { 490 FREE_C_HEAP_ARRAY(uint, _claims); 491 } 492 } 493 494 uint HeapRegionClaimer::offset_for_worker(uint worker_id) const { 495 assert(worker_id < _n_workers, "Invalid worker_id."); 496 return _n_regions * worker_id / _n_workers; 497 } 498 499 bool HeapRegionClaimer::is_region_claimed(uint region_index) const { 500 assert(region_index < _n_regions, "Invalid index."); 501 return _claims[region_index] == Claimed; 502 } 503 504 bool HeapRegionClaimer::claim_region(uint region_index) { 505 assert(region_index < _n_regions, "Invalid index."); 506 uint old_val = Atomic::cmpxchg(Claimed, &_claims[region_index], Unclaimed); 507 return old_val == Unclaimed; 508 }