1 /* 2 * Copyright (c) 2001, 2016, 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/g1CollectedHeap.inline.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) { 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); 82 83 // Also commit auxiliary data 84 _prev_bitmap_mapper->commit_regions(index, num_regions); 85 _next_bitmap_mapper->commit_regions(index, num_regions); 86 87 _bot_mapper->commit_regions(index, num_regions); 88 _cardtable_mapper->commit_regions(index, num_regions); 89 90 _card_counts_mapper->commit_regions(index, num_regions); 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) { 121 guarantee(num_regions > 0, "No point in calling this for zero regions"); 122 commit_regions(start, num_regions); 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 _regions.set_by_index(i, new_hr); 127 _allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1); 128 } 129 } 130 131 _available_map.par_set_range(start, start + num_regions, BitMap::unknown_range); 132 133 for (uint i = start; i < start + num_regions; i++) { 134 assert(is_available(i), "Just made region %u available but is apparently not.", i); 135 HeapRegion* hr = at(i); 136 if (G1CollectedHeap::heap()->hr_printer()->is_active()) { 137 G1CollectedHeap::heap()->hr_printer()->commit(hr); 138 } 139 HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i); 140 MemRegion mr(bottom, bottom + HeapRegion::GrainWords); 141 142 hr->initialize(mr); 143 insert_into_free_list(at(i)); 144 } 145 } 146 147 MemoryUsage HeapRegionManager::get_auxiliary_data_memory_usage() const { 148 size_t used_sz = 149 _prev_bitmap_mapper->committed_size() + 150 _next_bitmap_mapper->committed_size() + 151 _bot_mapper->committed_size() + 152 _cardtable_mapper->committed_size() + 153 _card_counts_mapper->committed_size(); 154 155 size_t committed_sz = 156 _prev_bitmap_mapper->reserved_size() + 157 _next_bitmap_mapper->reserved_size() + 158 _bot_mapper->reserved_size() + 159 _cardtable_mapper->reserved_size() + 160 _card_counts_mapper->reserved_size(); 161 162 return MemoryUsage(0, used_sz, committed_sz, committed_sz); 163 } 164 165 uint HeapRegionManager::expand_by(uint num_regions) { 166 return expand_at(0, num_regions); 167 } 168 169 uint HeapRegionManager::expand_at(uint start, uint num_regions) { 170 if (num_regions == 0) { 171 return 0; 172 } 173 174 uint cur = start; 175 uint idx_last_found = 0; 176 uint num_last_found = 0; 177 178 uint expanded = 0; 179 180 while (expanded < num_regions && 181 (num_last_found = find_unavailable_from_idx(cur, &idx_last_found)) > 0) { 182 uint to_expand = MIN2(num_regions - expanded, num_last_found); 183 make_regions_available(idx_last_found, to_expand); 184 expanded += to_expand; 185 cur = idx_last_found + num_last_found + 1; 186 } 187 188 verify_optional(); 189 return expanded; 190 } 191 192 uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) { 193 uint found = 0; 194 size_t length_found = 0; 195 uint cur = 0; 196 197 while (length_found < num && cur < max_length()) { 198 HeapRegion* hr = _regions.get_by_index(cur); 199 if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) { 200 // This region is a potential candidate for allocation into. 201 length_found++; 202 } else { 203 // This region is not a candidate. The next region is the next possible one. 204 found = cur + 1; 205 length_found = 0; 206 } 207 cur++; 208 } 209 210 if (length_found == num) { 211 for (uint i = found; i < (found + num); i++) { 212 HeapRegion* hr = _regions.get_by_index(i); 213 // sanity check 214 guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()), 215 "Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT 216 " that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr)); 217 } 218 return found; 219 } else { 220 return G1_NO_HRM_INDEX; 221 } 222 } 223 224 HeapRegion* HeapRegionManager::next_region_in_heap(const HeapRegion* r) const { 225 guarantee(r != NULL, "Start region must be a valid region"); 226 guarantee(is_available(r->hrm_index()), "Trying to iterate starting from region %u which is not in the heap", r->hrm_index()); 227 for (uint i = r->hrm_index() + 1; i < _allocated_heapregions_length; i++) { 228 HeapRegion* hr = _regions.get_by_index(i); 229 if (is_available(i)) { 230 return hr; 231 } 232 } 233 return NULL; 234 } 235 236 void HeapRegionManager::iterate(HeapRegionClosure* blk) const { 237 uint len = max_length(); 238 239 for (uint i = 0; i < len; i++) { 240 if (!is_available(i)) { 241 continue; 242 } 243 guarantee(at(i) != NULL, "Tried to access region %u that has a NULL HeapRegion*", i); 244 bool res = blk->doHeapRegion(at(i)); 245 if (res) { 246 blk->incomplete(); 247 return; 248 } 249 } 250 } 251 252 uint HeapRegionManager::find_unavailable_from_idx(uint start_idx, uint* res_idx) const { 253 guarantee(res_idx != NULL, "checking"); 254 guarantee(start_idx <= (max_length() + 1), "checking"); 255 256 uint num_regions = 0; 257 258 uint cur = start_idx; 259 while (cur < max_length() && is_available(cur)) { 260 cur++; 261 } 262 if (cur == max_length()) { 263 return num_regions; 264 } 265 *res_idx = cur; 266 while (cur < max_length() && !is_available(cur)) { 267 cur++; 268 } 269 num_regions = cur - *res_idx; 270 #ifdef ASSERT 271 for (uint i = *res_idx; i < (*res_idx + num_regions); i++) { 272 assert(!is_available(i), "just checking"); 273 } 274 assert(cur == max_length() || num_regions == 0 || is_available(cur), 275 "The region at the current position %u must be available or at the end of the heap.", cur); 276 #endif 277 return num_regions; 278 } 279 280 uint HeapRegionManager::find_highest_free(bool* expanded) { 281 // Loop downwards from the highest region index, looking for an 282 // entry which is either free or not yet committed. If not yet 283 // committed, expand_at that index. 284 uint curr = max_length() - 1; 285 while (true) { 286 HeapRegion *hr = _regions.get_by_index(curr); 287 if (hr == NULL) { 288 uint res = expand_at(curr, 1); 289 if (res == 1) { 290 *expanded = true; 291 return curr; 292 } 293 } else { 294 if (hr->is_free()) { 295 *expanded = false; 296 return curr; 297 } 298 } 299 if (curr == 0) { 300 return G1_NO_HRM_INDEX; 301 } 302 curr--; 303 } 304 } 305 306 bool HeapRegionManager::allocate_containing_regions(MemRegion range, size_t* commit_count) { 307 size_t commits = 0; 308 uint start_index = (uint)_regions.get_index_by_address(range.start()); 309 uint last_index = (uint)_regions.get_index_by_address(range.last()); 310 311 // Ensure that each G1 region in the range is free, returning false if not. 312 // Commit those that are not yet available, and keep count. 313 for (uint curr_index = start_index; curr_index <= last_index; curr_index++) { 314 if (!is_available(curr_index)) { 315 commits++; 316 expand_at(curr_index, 1); 317 } 318 HeapRegion* curr_region = _regions.get_by_index(curr_index); 319 if (!curr_region->is_free()) { 320 return false; 321 } 322 } 323 324 allocate_free_regions_starting_at(start_index, (last_index - start_index) + 1); 325 *commit_count = commits; 326 return true; 327 } 328 329 void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, HeapRegionClaimer* hrclaimer, bool concurrent) const { 330 const uint start_index = hrclaimer->start_region_for_worker(worker_id); 331 332 // Every worker will actually look at all regions, skipping over regions that 333 // are currently not committed. 334 // This also (potentially) iterates over regions newly allocated during GC. This 335 // is no problem except for some extra work. 336 const uint n_regions = hrclaimer->n_regions(); 337 for (uint count = 0; count < n_regions; count++) { 338 const uint index = (start_index + count) % n_regions; 339 assert(index < n_regions, "sanity"); 340 // Skip over unavailable regions 341 if (!is_available(index)) { 342 continue; 343 } 344 HeapRegion* r = _regions.get_by_index(index); 345 // We'll ignore regions already claimed. 346 // However, if the iteration is specified as concurrent, the values for 347 // is_starts_humongous and is_continues_humongous can not be trusted, 348 // and we should just blindly iterate over regions regardless of their 349 // humongous status. 350 if (hrclaimer->is_region_claimed(index)) { 351 continue; 352 } 353 // OK, try to claim it 354 if (!hrclaimer->claim_region(index)) { 355 continue; 356 } 357 bool res = blk->doHeapRegion(r); 358 if (res) { 359 return; 360 } 361 } 362 } 363 364 uint HeapRegionManager::shrink_by(uint num_regions_to_remove) { 365 assert(length() > 0, "the region sequence should not be empty"); 366 assert(length() <= _allocated_heapregions_length, "invariant"); 367 assert(_allocated_heapregions_length > 0, "we should have at least one region committed"); 368 assert(num_regions_to_remove < length(), "We should never remove all regions"); 369 370 if (num_regions_to_remove == 0) { 371 return 0; 372 } 373 374 uint removed = 0; 375 uint cur = _allocated_heapregions_length - 1; 376 uint idx_last_found = 0; 377 uint num_last_found = 0; 378 379 while ((removed < num_regions_to_remove) && 380 (num_last_found = find_empty_from_idx_reverse(cur, &idx_last_found)) > 0) { 381 uint to_remove = MIN2(num_regions_to_remove - removed, num_last_found); 382 383 shrink_at(idx_last_found + num_last_found - to_remove, to_remove); 384 385 cur = idx_last_found; 386 removed += to_remove; 387 } 388 389 verify_optional(); 390 391 return removed; 392 } 393 394 void HeapRegionManager::shrink_at(uint index, size_t num_regions) { 395 #ifdef ASSERT 396 for (uint i = index; i < (index + num_regions); i++) { 397 assert(is_available(i), "Expected available region at index %u", i); 398 assert(at(i)->is_empty(), "Expected empty region at index %u", i); 399 assert(at(i)->is_free(), "Expected free region at index %u", i); 400 } 401 #endif 402 uncommit_regions(index, num_regions); 403 } 404 405 uint HeapRegionManager::find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const { 406 guarantee(start_idx < _allocated_heapregions_length, "checking"); 407 guarantee(res_idx != NULL, "checking"); 408 409 uint num_regions_found = 0; 410 411 jlong cur = start_idx; 412 while (cur != -1 && !(is_available(cur) && at(cur)->is_empty())) { 413 cur--; 414 } 415 if (cur == -1) { 416 return num_regions_found; 417 } 418 jlong old_cur = cur; 419 // cur indexes the first empty region 420 while (cur != -1 && is_available(cur) && at(cur)->is_empty()) { 421 cur--; 422 } 423 *res_idx = cur + 1; 424 num_regions_found = old_cur - cur; 425 426 #ifdef ASSERT 427 for (uint i = *res_idx; i < (*res_idx + num_regions_found); i++) { 428 assert(at(i)->is_empty(), "just checking"); 429 } 430 #endif 431 return num_regions_found; 432 } 433 434 void HeapRegionManager::verify() { 435 guarantee(length() <= _allocated_heapregions_length, 436 "invariant: _length: %u _allocated_length: %u", 437 length(), _allocated_heapregions_length); 438 guarantee(_allocated_heapregions_length <= max_length(), 439 "invariant: _allocated_length: %u _max_length: %u", 440 _allocated_heapregions_length, max_length()); 441 442 bool prev_committed = true; 443 uint num_committed = 0; 444 HeapWord* prev_end = heap_bottom(); 445 for (uint i = 0; i < _allocated_heapregions_length; i++) { 446 if (!is_available(i)) { 447 prev_committed = false; 448 continue; 449 } 450 num_committed++; 451 HeapRegion* hr = _regions.get_by_index(i); 452 guarantee(hr != NULL, "invariant: i: %u", i); 453 guarantee(!prev_committed || hr->bottom() == prev_end, 454 "invariant i: %u " HR_FORMAT " prev_end: " PTR_FORMAT, 455 i, HR_FORMAT_PARAMS(hr), p2i(prev_end)); 456 guarantee(hr->hrm_index() == i, 457 "invariant: i: %u hrm_index(): %u", i, hr->hrm_index()); 458 // Asserts will fire if i is >= _length 459 HeapWord* addr = hr->bottom(); 460 guarantee(addr_to_region(addr) == hr, "sanity"); 461 // We cannot check whether the region is part of a particular set: at the time 462 // this method may be called, we have only completed allocation of the regions, 463 // but not put into a region set. 464 prev_committed = true; 465 prev_end = hr->end(); 466 } 467 for (uint i = _allocated_heapregions_length; i < max_length(); i++) { 468 guarantee(_regions.get_by_index(i) == NULL, "invariant i: %u", i); 469 } 470 471 guarantee(num_committed == _num_committed, "Found %u committed regions, but should be %u", num_committed, _num_committed); 472 _free_list.verify(); 473 } 474 475 #ifndef PRODUCT 476 void HeapRegionManager::verify_optional() { 477 verify(); 478 } 479 #endif // PRODUCT 480 481 HeapRegionClaimer::HeapRegionClaimer(uint n_workers) : 482 _n_workers(n_workers), _n_regions(G1CollectedHeap::heap()->_hrm._allocated_heapregions_length), _claims(NULL) { 483 assert(n_workers > 0, "Need at least one worker."); 484 uint* new_claims = NEW_C_HEAP_ARRAY(uint, _n_regions, mtGC); 485 memset(new_claims, Unclaimed, sizeof(*_claims) * _n_regions); 486 _claims = new_claims; 487 } 488 489 HeapRegionClaimer::~HeapRegionClaimer() { 490 if (_claims != NULL) { 491 FREE_C_HEAP_ARRAY(uint, _claims); 492 } 493 } 494 495 uint HeapRegionClaimer::start_region_for_worker(uint worker_id) const { 496 assert(worker_id < _n_workers, "Invalid worker_id."); 497 return _n_regions * worker_id / _n_workers; 498 } 499 500 bool HeapRegionClaimer::is_region_claimed(uint region_index) const { 501 assert(region_index < _n_regions, "Invalid index."); 502 return _claims[region_index] == Claimed; 503 } 504 505 bool HeapRegionClaimer::claim_region(uint region_index) { 506 assert(region_index < _n_regions, "Invalid index."); 507 uint old_val = Atomic::cmpxchg(Claimed, &_claims[region_index], Unclaimed); 508 return old_val == Unclaimed; 509 }