1 /* 2 * Copyright (c) 2016, 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/g1CollectedHeap.inline.hpp" 27 #include "gc/g1/g1CollectionSet.hpp" 28 #include "gc/g1/g1CollectorState.hpp" 29 #include "gc/g1/g1ParScanThreadState.hpp" 30 #include "gc/g1/g1Policy.hpp" 31 #include "gc/g1/heapRegion.inline.hpp" 32 #include "gc/g1/heapRegionRemSet.hpp" 33 #include "gc/g1/heapRegionSet.hpp" 34 #include "logging/logStream.hpp" 35 #include "utilities/debug.hpp" 36 #include "utilities/globalDefinitions.hpp" 37 #include "utilities/quickSort.hpp" 38 39 G1CollectorState* G1CollectionSet::collector_state() { 40 return _g1h->collector_state(); 41 } 42 43 G1GCPhaseTimes* G1CollectionSet::phase_times() { 44 return _policy->phase_times(); 45 } 46 47 double G1CollectionSet::predict_region_elapsed_time_ms(HeapRegion* hr) { 48 return _policy->predict_region_elapsed_time_ms(hr, collector_state()->in_young_only_phase()); 49 } 50 51 G1CollectionSet::G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy) : 52 _g1h(g1h), 53 _policy(policy), 54 _candidates(NULL), 55 _eden_region_length(0), 56 _survivor_region_length(0), 57 _old_region_length(0), 58 _collection_set_regions(NULL), 59 _collection_set_cur_length(0), 60 _collection_set_max_length(0), 61 _optional_regions(NULL), 62 _optional_region_length(0), 63 _optional_region_max_length(0), 64 _bytes_used_before(0), 65 _recorded_rs_lengths(0), 66 _inc_build_state(Inactive), 67 _inc_bytes_used_before(0), 68 _inc_recorded_rs_lengths(0), 69 _inc_recorded_rs_lengths_diffs(0), 70 _inc_predicted_elapsed_time_ms(0.0), 71 _inc_predicted_elapsed_time_ms_diffs(0.0) { 72 } 73 74 G1CollectionSet::~G1CollectionSet() { 75 if (_collection_set_regions != NULL) { 76 FREE_C_HEAP_ARRAY(uint, _collection_set_regions); 77 } 78 free_optional_regions(); 79 clear_candidates(); 80 } 81 82 void G1CollectionSet::init_region_lengths(uint eden_cset_region_length, 83 uint survivor_cset_region_length) { 84 assert_at_safepoint_on_vm_thread(); 85 86 _eden_region_length = eden_cset_region_length; 87 _survivor_region_length = survivor_cset_region_length; 88 89 assert((size_t) young_region_length() == _collection_set_cur_length, 90 "Young region length %u should match collection set length " SIZE_FORMAT, young_region_length(), _collection_set_cur_length); 91 92 _old_region_length = 0; 93 _optional_region_length = 0; 94 } 95 96 void G1CollectionSet::initialize(uint max_region_length) { 97 guarantee(_collection_set_regions == NULL, "Must only initialize once."); 98 _collection_set_max_length = max_region_length; 99 _collection_set_regions = NEW_C_HEAP_ARRAY(uint, max_region_length, mtGC); 100 } 101 102 void G1CollectionSet::initialize_optional(uint max_length) { 103 assert(_optional_regions == NULL, "Already initialized"); 104 assert(_optional_region_length == 0, "Already initialized"); 105 assert(_optional_region_max_length == 0, "Already initialized"); 106 _optional_region_max_length = max_length; 107 _optional_regions = NEW_C_HEAP_ARRAY(HeapRegion*, _optional_region_max_length, mtGC); 108 } 109 110 void G1CollectionSet::free_optional_regions() { 111 _optional_region_length = 0; 112 _optional_region_max_length = 0; 113 if (_optional_regions != NULL) { 114 FREE_C_HEAP_ARRAY(HeapRegion*, _optional_regions); 115 _optional_regions = NULL; 116 } 117 } 118 119 void G1CollectionSet::set_recorded_rs_lengths(size_t rs_lengths) { 120 _recorded_rs_lengths = rs_lengths; 121 } 122 123 // Add the heap region at the head of the non-incremental collection set 124 void G1CollectionSet::add_old_region(HeapRegion* hr) { 125 assert_at_safepoint_on_vm_thread(); 126 127 assert(_inc_build_state == Active || hr->index_in_opt_cset() != G1OptionalCSet::InvalidCSetIndex, 128 "Precondition, actively building cset or adding optional later on"); 129 assert(hr->is_old(), "the region should be old"); 130 131 assert(!hr->in_collection_set(), "should not already be in the CSet"); 132 _g1h->register_old_region_with_cset(hr); 133 134 _collection_set_regions[_collection_set_cur_length++] = hr->hrm_index(); 135 assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set now larger than maximum size."); 136 137 _bytes_used_before += hr->used(); 138 size_t rs_length = hr->rem_set()->occupied(); 139 _recorded_rs_lengths += rs_length; 140 _old_region_length += 1; 141 142 log_trace(gc, cset)("Added old region %d to collection set", hr->hrm_index()); 143 } 144 145 void G1CollectionSet::add_optional_region(HeapRegion* hr) { 146 assert(!optional_is_full(), "Precondition, must have room left for this region"); 147 assert(hr->is_old(), "the region should be old"); 148 assert(!hr->in_collection_set(), "should not already be in the CSet"); 149 150 _g1h->register_optional_region_with_cset(hr); 151 152 _optional_regions[_optional_region_length] = hr; 153 uint index = _optional_region_length++; 154 hr->set_index_in_opt_cset(index); 155 156 log_trace(gc, cset)("Added region %d to optional collection set (%u)", hr->hrm_index(), _optional_region_length); 157 } 158 159 // Initialize the per-collection-set information 160 void G1CollectionSet::start_incremental_building() { 161 assert(_collection_set_cur_length == 0, "Collection set must be empty before starting a new collection set."); 162 assert(_inc_build_state == Inactive, "Precondition"); 163 164 _inc_bytes_used_before = 0; 165 166 _inc_recorded_rs_lengths = 0; 167 _inc_recorded_rs_lengths_diffs = 0; 168 _inc_predicted_elapsed_time_ms = 0.0; 169 _inc_predicted_elapsed_time_ms_diffs = 0.0; 170 _inc_build_state = Active; 171 } 172 173 void G1CollectionSet::finalize_incremental_building() { 174 assert(_inc_build_state == Active, "Precondition"); 175 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint"); 176 177 // The two "main" fields, _inc_recorded_rs_lengths and 178 // _inc_predicted_elapsed_time_ms, are updated by the thread 179 // that adds a new region to the CSet. Further updates by the 180 // concurrent refinement thread that samples the young RSet lengths 181 // are accumulated in the *_diffs fields. Here we add the diffs to 182 // the "main" fields. 183 184 if (_inc_recorded_rs_lengths_diffs >= 0) { 185 _inc_recorded_rs_lengths += _inc_recorded_rs_lengths_diffs; 186 } else { 187 // This is defensive. The diff should in theory be always positive 188 // as RSets can only grow between GCs. However, given that we 189 // sample their size concurrently with other threads updating them 190 // it's possible that we might get the wrong size back, which 191 // could make the calculations somewhat inaccurate. 192 size_t diffs = (size_t) (-_inc_recorded_rs_lengths_diffs); 193 if (_inc_recorded_rs_lengths >= diffs) { 194 _inc_recorded_rs_lengths -= diffs; 195 } else { 196 _inc_recorded_rs_lengths = 0; 197 } 198 } 199 _inc_predicted_elapsed_time_ms += _inc_predicted_elapsed_time_ms_diffs; 200 201 _inc_recorded_rs_lengths_diffs = 0; 202 _inc_predicted_elapsed_time_ms_diffs = 0.0; 203 } 204 205 void G1CollectionSet::clear() { 206 assert_at_safepoint_on_vm_thread(); 207 _collection_set_cur_length = 0; 208 _optional_region_length = 0; 209 } 210 211 void G1CollectionSet::iterate(HeapRegionClosure* cl) const { 212 iterate_from(cl, 0, 1); 213 } 214 215 void G1CollectionSet::iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const { 216 size_t len = _collection_set_cur_length; 217 OrderAccess::loadload(); 218 if (len == 0) { 219 return; 220 } 221 size_t start_pos = (worker_id * len) / total_workers; 222 size_t cur_pos = start_pos; 223 224 do { 225 HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos]); 226 bool result = cl->do_heap_region(r); 227 if (result) { 228 cl->set_incomplete(); 229 return; 230 } 231 cur_pos++; 232 if (cur_pos == len) { 233 cur_pos = 0; 234 } 235 } while (cur_pos != start_pos); 236 } 237 238 void G1CollectionSet::update_young_region_prediction(HeapRegion* hr, 239 size_t new_rs_length) { 240 // Update the CSet information that is dependent on the new RS length 241 assert(hr->is_young(), "Precondition"); 242 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at a safepoint"); 243 244 // We could have updated _inc_recorded_rs_lengths and 245 // _inc_predicted_elapsed_time_ms directly but we'd need to do 246 // that atomically, as this code is executed by a concurrent 247 // refinement thread, potentially concurrently with a mutator thread 248 // allocating a new region and also updating the same fields. To 249 // avoid the atomic operations we accumulate these updates on two 250 // separate fields (*_diffs) and we'll just add them to the "main" 251 // fields at the start of a GC. 252 253 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length(); 254 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length; 255 _inc_recorded_rs_lengths_diffs += rs_lengths_diff; 256 257 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms(); 258 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr); 259 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms; 260 _inc_predicted_elapsed_time_ms_diffs += elapsed_ms_diff; 261 262 hr->set_recorded_rs_length(new_rs_length); 263 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms); 264 } 265 266 void G1CollectionSet::add_young_region_common(HeapRegion* hr) { 267 assert(hr->is_young(), "invariant"); 268 assert(_inc_build_state == Active, "Precondition"); 269 270 size_t collection_set_length = _collection_set_cur_length; 271 assert(collection_set_length <= INT_MAX, "Collection set is too large with %d entries", (int)collection_set_length); 272 hr->set_young_index_in_cset((int)collection_set_length); 273 274 _collection_set_regions[collection_set_length] = hr->hrm_index(); 275 // Concurrent readers must observe the store of the value in the array before an 276 // update to the length field. 277 OrderAccess::storestore(); 278 _collection_set_cur_length++; 279 assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set larger than maximum allowed."); 280 281 // This routine is used when: 282 // * adding survivor regions to the incremental cset at the end of an 283 // evacuation pause or 284 // * adding the current allocation region to the incremental cset 285 // when it is retired. 286 // Therefore this routine may be called at a safepoint by the 287 // VM thread, or in-between safepoints by mutator threads (when 288 // retiring the current allocation region) 289 // We need to clear and set the cached recorded/cached collection set 290 // information in the heap region here (before the region gets added 291 // to the collection set). An individual heap region's cached values 292 // are calculated, aggregated with the policy collection set info, 293 // and cached in the heap region here (initially) and (subsequently) 294 // by the Young List sampling code. 295 // Ignore calls to this due to retirement during full gc. 296 297 if (!_g1h->collector_state()->in_full_gc()) { 298 size_t rs_length = hr->rem_set()->occupied(); 299 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr); 300 301 // Cache the values we have added to the aggregated information 302 // in the heap region in case we have to remove this region from 303 // the incremental collection set, or it is updated by the 304 // rset sampling code 305 hr->set_recorded_rs_length(rs_length); 306 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms); 307 308 _inc_recorded_rs_lengths += rs_length; 309 _inc_predicted_elapsed_time_ms += region_elapsed_time_ms; 310 _inc_bytes_used_before += hr->used(); 311 } 312 313 assert(!hr->in_collection_set(), "invariant"); 314 _g1h->register_young_region_with_cset(hr); 315 } 316 317 void G1CollectionSet::add_survivor_regions(HeapRegion* hr) { 318 assert(hr->is_survivor(), "Must only add survivor regions, but is %s", hr->get_type_str()); 319 add_young_region_common(hr); 320 } 321 322 void G1CollectionSet::add_eden_region(HeapRegion* hr) { 323 assert(hr->is_eden(), "Must only add eden regions, but is %s", hr->get_type_str()); 324 add_young_region_common(hr); 325 } 326 327 #ifndef PRODUCT 328 class G1VerifyYoungAgesClosure : public HeapRegionClosure { 329 public: 330 bool _valid; 331 public: 332 G1VerifyYoungAgesClosure() : HeapRegionClosure(), _valid(true) { } 333 334 virtual bool do_heap_region(HeapRegion* r) { 335 guarantee(r->is_young(), "Region must be young but is %s", r->get_type_str()); 336 337 SurvRateGroup* group = r->surv_rate_group(); 338 339 if (group == NULL) { 340 log_error(gc, verify)("## encountered NULL surv_rate_group in young region"); 341 _valid = false; 342 } 343 344 if (r->age_in_surv_rate_group() < 0) { 345 log_error(gc, verify)("## encountered negative age in young region"); 346 _valid = false; 347 } 348 349 return false; 350 } 351 352 bool valid() const { return _valid; } 353 }; 354 355 bool G1CollectionSet::verify_young_ages() { 356 assert_at_safepoint_on_vm_thread(); 357 358 G1VerifyYoungAgesClosure cl; 359 iterate(&cl); 360 361 if (!cl.valid()) { 362 LogStreamHandle(Error, gc, verify) log; 363 print(&log); 364 } 365 366 return cl.valid(); 367 } 368 369 class G1PrintCollectionSetDetailClosure : public HeapRegionClosure { 370 outputStream* _st; 371 public: 372 G1PrintCollectionSetDetailClosure(outputStream* st) : HeapRegionClosure(), _st(st) { } 373 374 virtual bool do_heap_region(HeapRegion* r) { 375 assert(r->in_collection_set(), "Region %u should be in collection set", r->hrm_index()); 376 _st->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d", 377 HR_FORMAT_PARAMS(r), 378 p2i(r->prev_top_at_mark_start()), 379 p2i(r->next_top_at_mark_start()), 380 r->age_in_surv_rate_group_cond()); 381 return false; 382 } 383 }; 384 385 void G1CollectionSet::print(outputStream* st) { 386 st->print_cr("\nCollection_set:"); 387 388 G1PrintCollectionSetDetailClosure cl(st); 389 iterate(&cl); 390 } 391 #endif // !PRODUCT 392 393 double G1CollectionSet::finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors) { 394 double young_start_time_sec = os::elapsedTime(); 395 396 finalize_incremental_building(); 397 398 guarantee(target_pause_time_ms > 0.0, 399 "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms); 400 401 size_t pending_cards = _policy->pending_cards(); 402 double base_time_ms = _policy->predict_base_elapsed_time_ms(pending_cards); 403 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0); 404 405 log_trace(gc, ergo, cset)("Start choosing CSet. pending cards: " SIZE_FORMAT " predicted base time: %1.2fms remaining time: %1.2fms target pause time: %1.2fms", 406 pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms); 407 408 // The young list is laid with the survivor regions from the previous 409 // pause are appended to the RHS of the young list, i.e. 410 // [Newly Young Regions ++ Survivors from last pause]. 411 412 uint survivor_region_length = survivors->length(); 413 uint eden_region_length = _g1h->eden_regions_count(); 414 init_region_lengths(eden_region_length, survivor_region_length); 415 416 verify_young_cset_indices(); 417 418 // Clear the fields that point to the survivor list - they are all young now. 419 survivors->convert_to_eden(); 420 421 _bytes_used_before = _inc_bytes_used_before; 422 time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0); 423 424 log_trace(gc, ergo, cset)("Add young regions to CSet. eden: %u regions, survivors: %u regions, predicted young region time: %1.2fms, target pause time: %1.2fms", 425 eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms); 426 427 // The number of recorded young regions is the incremental 428 // collection set's current size 429 set_recorded_rs_lengths(_inc_recorded_rs_lengths); 430 431 double young_end_time_sec = os::elapsedTime(); 432 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0); 433 434 return time_remaining_ms; 435 } 436 437 void G1CollectionSet::add_as_old(HeapRegion* hr) { 438 candidates()->pop_front(); // already have region via peek() 439 _g1h->old_set_remove(hr); 440 add_old_region(hr); 441 } 442 443 void G1CollectionSet::add_as_optional(HeapRegion* hr) { 444 assert(_optional_regions != NULL, "Must not be called before array is allocated"); 445 candidates()->pop_front(); // already have region via peek() 446 _g1h->old_set_remove(hr); 447 add_optional_region(hr); 448 } 449 450 bool G1CollectionSet::optional_is_full() { 451 assert(_optional_region_length <= _optional_region_max_length, "Invariant"); 452 return _optional_region_length == _optional_region_max_length; 453 } 454 455 void G1CollectionSet::clear_optional_region(const HeapRegion* hr) { 456 assert(_optional_regions != NULL, "Must not be called before array is allocated"); 457 uint index = hr->index_in_opt_cset(); 458 _optional_regions[index] = NULL; 459 } 460 461 static int compare_region_idx(const uint a, const uint b) { 462 if (a > b) { 463 return 1; 464 } else if (a == b) { 465 return 0; 466 } else { 467 return -1; 468 } 469 } 470 471 void G1CollectionSet::finalize_old_part(double time_remaining_ms) { 472 double non_young_start_time_sec = os::elapsedTime(); 473 double predicted_old_time_ms = 0.0; 474 double predicted_optional_time_ms = 0.0; 475 double optional_threshold_ms = time_remaining_ms * _policy->optional_prediction_fraction(); 476 uint expensive_region_num = 0; 477 478 if (collector_state()->in_mixed_phase()) { 479 candidates()->verify(); 480 const uint min_old_cset_length = _policy->calc_min_old_cset_length(); 481 const uint max_old_cset_length = MAX2(min_old_cset_length, _policy->calc_max_old_cset_length()); 482 bool check_time_remaining = _policy->adaptive_young_list_length(); 483 484 initialize_optional(max_old_cset_length - min_old_cset_length); 485 log_debug(gc, ergo, cset)("Start adding old regions for mixed gc. min %u regions, max %u regions, " 486 "time remaining %1.2fms, optional threshold %1.2fms", 487 min_old_cset_length, max_old_cset_length, time_remaining_ms, optional_threshold_ms); 488 489 HeapRegion* hr = candidates()->peek_front(); 490 while (hr != NULL) { 491 if (old_region_length() + optional_region_length() >= max_old_cset_length) { 492 // Added maximum number of old regions to the CSet. 493 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached max). " 494 "old %u regions, optional %u regions", 495 old_region_length(), optional_region_length()); 496 break; 497 } 498 499 // Stop adding regions if the remaining reclaimable space is 500 // not above G1HeapWastePercent. 501 size_t reclaimable_bytes = candidates()->remaining_reclaimable_bytes(); 502 double reclaimable_percent = _policy->reclaimable_bytes_percent(reclaimable_bytes); 503 double threshold = (double) G1HeapWastePercent; 504 if (reclaimable_percent <= threshold) { 505 // We've added enough old regions that the amount of uncollected 506 // reclaimable space is at or below the waste threshold. Stop 507 // adding old regions to the CSet. 508 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (reclaimable percentage not over threshold). " 509 "reclaimable: " SIZE_FORMAT "%s (%1.2f%%) threshold: " UINTX_FORMAT "%%", 510 byte_size_in_proper_unit(reclaimable_bytes), proper_unit_for_byte_size(reclaimable_bytes), 511 reclaimable_percent, G1HeapWastePercent); 512 break; 513 } 514 515 double predicted_time_ms = predict_region_elapsed_time_ms(hr); 516 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0); 517 // Add regions to old set until we reach minimum amount 518 if (old_region_length() < min_old_cset_length) { 519 predicted_old_time_ms += predicted_time_ms; 520 add_as_old(hr); 521 // Record the number of regions added when no time remaining 522 if (time_remaining_ms == 0.0) { 523 expensive_region_num++; 524 } 525 } else { 526 // In the non-auto-tuning case, we'll finish adding regions 527 // to the CSet if we reach the minimum. 528 if (!check_time_remaining) { 529 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached min)."); 530 break; 531 } 532 // Keep adding regions to old set until we reach optional threshold 533 if (time_remaining_ms > optional_threshold_ms) { 534 predicted_old_time_ms += predicted_time_ms; 535 add_as_old(hr); 536 } else if (time_remaining_ms > 0) { 537 // Keep adding optional regions until time is up 538 if (!optional_is_full()) { 539 predicted_optional_time_ms += predicted_time_ms; 540 add_as_optional(hr); 541 } else { 542 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (optional set full)."); 543 break; 544 } 545 } else { 546 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (predicted time is too high)."); 547 break; 548 } 549 } 550 hr = candidates()->peek_front(); 551 } 552 if (hr == NULL) { 553 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (candidate old regions not available)"); 554 } 555 556 candidates()->verify(); 557 } 558 559 stop_incremental_building(); 560 561 log_debug(gc, ergo, cset)("Finish choosing CSet regions old: %u, optional: %u, " 562 "predicted old time: %1.2fms, predicted optional time: %1.2fms, time remaining: %1.2f", 563 old_region_length(), optional_region_length(), 564 predicted_old_time_ms, predicted_optional_time_ms, time_remaining_ms); 565 if (expensive_region_num > 0) { 566 log_debug(gc, ergo, cset)("CSet contains %u old regions that were added although the predicted time was too high.", 567 expensive_region_num); 568 } 569 570 double non_young_end_time_sec = os::elapsedTime(); 571 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0); 572 573 QuickSort::sort(_collection_set_regions, _collection_set_cur_length, compare_region_idx, true); 574 } 575 576 HeapRegion* G1OptionalCSet::region_at(uint index) { 577 return _cset->optional_region_at(index); 578 } 579 580 void G1OptionalCSet::prepare_evacuation(double time_limit) { 581 assert(_current_index == _current_limit, "Before prepare no regions should be ready for evac"); 582 583 uint prepared_regions = 0; 584 double prediction_ms = 0; 585 586 _prepare_failed = true; 587 for (uint i = _current_index; i < _cset->optional_region_length(); i++) { 588 HeapRegion* hr = region_at(i); 589 prediction_ms += _cset->predict_region_elapsed_time_ms(hr); 590 if (prediction_ms > time_limit) { 591 log_debug(gc, cset)("Prepared %u regions for optional evacuation. Predicted time: %.3fms", prepared_regions, prediction_ms); 592 return; 593 } 594 595 // This region will be included in the next optional evacuation. 596 prepare_to_evacuate_optional_region(hr); 597 prepared_regions++; 598 _current_limit++; 599 _prepare_failed = false; 600 } 601 602 log_debug(gc, cset)("Prepared all %u regions for optional evacuation. Predicted time: %.3fms", 603 prepared_regions, prediction_ms); 604 } 605 606 bool G1OptionalCSet::prepare_failed() { 607 return _prepare_failed; 608 } 609 610 void G1OptionalCSet::complete_evacuation() { 611 _evacuation_failed = false; 612 for (uint i = _current_index; i < _current_limit; i++) { 613 HeapRegion* hr = region_at(i); 614 _cset->clear_optional_region(hr); 615 if (hr->evacuation_failed()){ 616 _evacuation_failed = true; 617 } 618 } 619 _current_index = _current_limit; 620 } 621 622 bool G1OptionalCSet::evacuation_failed() { 623 return _evacuation_failed; 624 } 625 626 G1OptionalCSet::~G1OptionalCSet() { 627 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 628 while (!is_empty()) { 629 // We want to return regions not evacuated to the collection set candidates 630 // in reverse order to maintain the old order. 631 HeapRegion* hr = _cset->remove_last_optional_region(); 632 assert(hr != NULL, "Should be valid region left"); 633 _pset->record_unused_optional_region(hr); 634 g1h->old_set_add(hr); 635 g1h->clear_in_cset(hr); 636 hr->set_index_in_opt_cset(InvalidCSetIndex); 637 _cset->candidates()->push_front(hr); 638 } 639 _cset->free_optional_regions(); 640 } 641 642 uint G1OptionalCSet::size() { 643 return _cset->optional_region_length() - _current_index; 644 } 645 646 bool G1OptionalCSet::is_empty() { 647 return size() == 0; 648 } 649 650 void G1OptionalCSet::prepare_to_evacuate_optional_region(HeapRegion* hr) { 651 log_trace(gc, cset)("Adding region %u for optional evacuation", hr->hrm_index()); 652 G1CollectedHeap::heap()->clear_in_cset(hr); 653 _cset->add_old_region(hr); 654 } 655 656 #ifdef ASSERT 657 class G1VerifyYoungCSetIndicesClosure : public HeapRegionClosure { 658 private: 659 size_t _young_length; 660 int* _heap_region_indices; 661 public: 662 G1VerifyYoungCSetIndicesClosure(size_t young_length) : HeapRegionClosure(), _young_length(young_length) { 663 _heap_region_indices = NEW_C_HEAP_ARRAY(int, young_length, mtGC); 664 for (size_t i = 0; i < young_length; i++) { 665 _heap_region_indices[i] = -1; 666 } 667 } 668 ~G1VerifyYoungCSetIndicesClosure() { 669 FREE_C_HEAP_ARRAY(int, _heap_region_indices); 670 } 671 672 virtual bool do_heap_region(HeapRegion* r) { 673 const int idx = r->young_index_in_cset(); 674 675 assert(idx > -1, "Young index must be set for all regions in the incremental collection set but is not for region %u.", r->hrm_index()); 676 assert((size_t)idx < _young_length, "Young cset index too large for region %u", r->hrm_index()); 677 678 assert(_heap_region_indices[idx] == -1, 679 "Index %d used by multiple regions, first use by region %u, second by region %u", 680 idx, _heap_region_indices[idx], r->hrm_index()); 681 682 _heap_region_indices[idx] = r->hrm_index(); 683 684 return false; 685 } 686 }; 687 688 void G1CollectionSet::verify_young_cset_indices() const { 689 assert_at_safepoint_on_vm_thread(); 690 691 G1VerifyYoungCSetIndicesClosure cl(_collection_set_cur_length); 692 iterate(&cl); 693 } 694 #endif