1 /* 2 * Copyright (c) 2016, 2018, 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/g1Policy.hpp" 30 #include "gc/g1/heapRegion.inline.hpp" 31 #include "gc/g1/heapRegionRemSet.hpp" 32 #include "gc/g1/heapRegionSet.hpp" 33 #include "logging/logStream.hpp" 34 #include "utilities/debug.hpp" 35 #include "utilities/globalDefinitions.hpp" 36 #include "utilities/quickSort.hpp" 37 38 G1CollectorState* G1CollectionSet::collector_state() { 39 return _g1h->collector_state(); 40 } 41 42 G1GCPhaseTimes* G1CollectionSet::phase_times() { 43 return _policy->phase_times(); 44 } 45 46 CollectionSetChooser* G1CollectionSet::cset_chooser() { 47 return _cset_chooser; 48 } 49 50 double G1CollectionSet::predict_region_elapsed_time_ms(HeapRegion* hr) { 51 return _policy->predict_region_elapsed_time_ms(hr, collector_state()->in_young_only_phase()); 52 } 53 54 G1CollectionSet::G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy) : 55 _g1h(g1h), 56 _policy(policy), 57 _cset_chooser(new CollectionSetChooser()), 58 _eden_region_length(0), 59 _survivor_region_length(0), 60 _old_region_length(0), 61 _collection_set_regions(NULL), 62 _collection_set_cur_length(0), 63 _collection_set_max_length(0), 64 _optional_regions(NULL), 65 _optional_region_length(0), 66 _optional_region_max_length(0), 67 _bytes_used_before(0), 68 _recorded_rs_lengths(0), 69 _inc_build_state(Inactive), 70 _inc_bytes_used_before(0), 71 _inc_recorded_rs_lengths(0), 72 _inc_recorded_rs_lengths_diffs(0), 73 _inc_predicted_elapsed_time_ms(0.0), 74 _inc_predicted_elapsed_time_ms_diffs(0.0) { 75 } 76 77 G1CollectionSet::~G1CollectionSet() { 78 if (_collection_set_regions != NULL) { 79 FREE_C_HEAP_ARRAY(uint, _collection_set_regions); 80 } 81 free_optional_regions(); 82 delete _cset_chooser; 83 } 84 85 void G1CollectionSet::init_region_lengths(uint eden_cset_region_length, 86 uint survivor_cset_region_length) { 87 assert_at_safepoint_on_vm_thread(); 88 89 _eden_region_length = eden_cset_region_length; 90 _survivor_region_length = survivor_cset_region_length; 91 92 assert((size_t) young_region_length() == _collection_set_cur_length, 93 "Young region length %u should match collection set length " SIZE_FORMAT, young_region_length(), _collection_set_cur_length); 94 95 _old_region_length = 0; 96 _optional_region_length = 0; 97 } 98 99 void G1CollectionSet::initialize(uint max_region_length) { 100 guarantee(_collection_set_regions == NULL, "Must only initialize once."); 101 _collection_set_max_length = max_region_length; 102 _collection_set_regions = NEW_C_HEAP_ARRAY(uint, max_region_length, mtGC); 103 } 104 105 void G1CollectionSet::initialize_optional(uint max_length) { 106 assert(_optional_regions == NULL, "Already initialized"); 107 _optional_region_max_length = max_length; 108 _optional_regions = NEW_C_HEAP_ARRAY(HeapRegion*, _optional_region_max_length, mtGC); 109 } 110 111 void G1CollectionSet::free_optional_regions() { 112 _optional_region_length = 0; 113 _optional_region_max_length = 0; 114 if (_optional_regions != NULL) { 115 FREE_C_HEAP_ARRAY(HeapRegion*, _optional_regions); 116 _optional_regions = NULL; 117 } 118 } 119 120 void G1CollectionSet::set_recorded_rs_lengths(size_t rs_lengths) { 121 _recorded_rs_lengths = rs_lengths; 122 } 123 124 // Add the heap region at the head of the non-incremental collection set 125 void G1CollectionSet::add_old_region(HeapRegion* hr) { 126 assert_at_safepoint_on_vm_thread(); 127 128 assert(_inc_build_state == Active || hr->index_in_opt_cset() != G1OptionalCSet::InvalidCSetIndex, 129 "Precondition, actively building cset or adding optional later on"); 130 assert(hr->is_old(), "the region should be old"); 131 132 assert(!hr->in_collection_set(), "should not already be in the CSet"); 133 _g1h->register_old_region_with_cset(hr); 134 135 _collection_set_regions[_collection_set_cur_length++] = hr->hrm_index(); 136 assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set now larger than maximum size."); 137 138 _bytes_used_before += hr->used(); 139 size_t rs_length = hr->rem_set()->occupied(); 140 _recorded_rs_lengths += rs_length; 141 _old_region_length += 1; 142 143 log_trace(gc, cset)("Added old region %d to collection set", hr->hrm_index()); 144 } 145 146 void G1CollectionSet::add_optional_region(HeapRegion* hr) { 147 assert(!optional_is_full(), "Precondition, must have room left for this region"); 148 assert(hr->is_old(), "the region should be old"); 149 assert(!hr->in_collection_set(), "should not already be in the CSet"); 150 151 _g1h->register_optional_region_with_cset(hr); 152 153 _optional_regions[_optional_region_length] = hr; 154 uint index = _optional_region_length++; 155 hr->set_index_in_opt_cset(index); 156 157 log_trace(gc, cset)("Added region %d to optional collection set (%u)", hr->hrm_index(), _optional_region_length); 158 } 159 160 // Initialize the per-collection-set information 161 void G1CollectionSet::start_incremental_building() { 162 assert(_collection_set_cur_length == 0, "Collection set must be empty before starting a new collection set."); 163 assert(_inc_build_state == Inactive, "Precondition"); 164 165 _inc_bytes_used_before = 0; 166 167 _inc_recorded_rs_lengths = 0; 168 _inc_recorded_rs_lengths_diffs = 0; 169 _inc_predicted_elapsed_time_ms = 0.0; 170 _inc_predicted_elapsed_time_ms_diffs = 0.0; 171 _inc_build_state = Active; 172 } 173 174 void G1CollectionSet::finalize_incremental_building() { 175 assert(_inc_build_state == Active, "Precondition"); 176 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint"); 177 178 // The two "main" fields, _inc_recorded_rs_lengths and 179 // _inc_predicted_elapsed_time_ms, are updated by the thread 180 // that adds a new region to the CSet. Further updates by the 181 // concurrent refinement thread that samples the young RSet lengths 182 // are accumulated in the *_diffs fields. Here we add the diffs to 183 // the "main" fields. 184 185 if (_inc_recorded_rs_lengths_diffs >= 0) { 186 _inc_recorded_rs_lengths += _inc_recorded_rs_lengths_diffs; 187 } else { 188 // This is defensive. The diff should in theory be always positive 189 // as RSets can only grow between GCs. However, given that we 190 // sample their size concurrently with other threads updating them 191 // it's possible that we might get the wrong size back, which 192 // could make the calculations somewhat inaccurate. 193 size_t diffs = (size_t) (-_inc_recorded_rs_lengths_diffs); 194 if (_inc_recorded_rs_lengths >= diffs) { 195 _inc_recorded_rs_lengths -= diffs; 196 } else { 197 _inc_recorded_rs_lengths = 0; 198 } 199 } 200 _inc_predicted_elapsed_time_ms += _inc_predicted_elapsed_time_ms_diffs; 201 202 _inc_recorded_rs_lengths_diffs = 0; 203 _inc_predicted_elapsed_time_ms_diffs = 0.0; 204 } 205 206 void G1CollectionSet::clear() { 207 assert_at_safepoint_on_vm_thread(); 208 _collection_set_cur_length = 0; 209 _optional_region_length = 0; 210 } 211 212 void G1CollectionSet::iterate(HeapRegionClosure* cl) const { 213 iterate_from(cl, 0, 1); 214 } 215 216 void G1CollectionSet::iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const { 217 size_t len = _collection_set_cur_length; 218 OrderAccess::loadload(); 219 if (len == 0) { 220 return; 221 } 222 size_t start_pos = (worker_id * len) / total_workers; 223 size_t cur_pos = start_pos; 224 225 do { 226 HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos]); 227 bool result = cl->do_heap_region(r); 228 if (result) { 229 cl->set_incomplete(); 230 return; 231 } 232 cur_pos++; 233 if (cur_pos == len) { 234 cur_pos = 0; 235 } 236 } while (cur_pos != start_pos); 237 } 238 239 void G1CollectionSet::update_young_region_prediction(HeapRegion* hr, 240 size_t new_rs_length) { 241 // Update the CSet information that is dependent on the new RS length 242 assert(hr->is_young(), "Precondition"); 243 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at a safepoint"); 244 245 // We could have updated _inc_recorded_rs_lengths and 246 // _inc_predicted_elapsed_time_ms directly but we'd need to do 247 // that atomically, as this code is executed by a concurrent 248 // refinement thread, potentially concurrently with a mutator thread 249 // allocating a new region and also updating the same fields. To 250 // avoid the atomic operations we accumulate these updates on two 251 // separate fields (*_diffs) and we'll just add them to the "main" 252 // fields at the start of a GC. 253 254 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length(); 255 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length; 256 _inc_recorded_rs_lengths_diffs += rs_lengths_diff; 257 258 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms(); 259 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr); 260 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms; 261 _inc_predicted_elapsed_time_ms_diffs += elapsed_ms_diff; 262 263 hr->set_recorded_rs_length(new_rs_length); 264 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms); 265 } 266 267 void G1CollectionSet::add_young_region_common(HeapRegion* hr) { 268 assert(hr->is_young(), "invariant"); 269 assert(_inc_build_state == Active, "Precondition"); 270 271 size_t collection_set_length = _collection_set_cur_length; 272 assert(collection_set_length <= INT_MAX, "Collection set is too large with %d entries", (int)collection_set_length); 273 hr->set_young_index_in_cset((int)collection_set_length); 274 275 _collection_set_regions[collection_set_length] = hr->hrm_index(); 276 // Concurrent readers must observe the store of the value in the array before an 277 // update to the length field. 278 OrderAccess::storestore(); 279 _collection_set_cur_length++; 280 assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set larger than maximum allowed."); 281 282 // This routine is used when: 283 // * adding survivor regions to the incremental cset at the end of an 284 // evacuation pause or 285 // * adding the current allocation region to the incremental cset 286 // when it is retired. 287 // Therefore this routine may be called at a safepoint by the 288 // VM thread, or in-between safepoints by mutator threads (when 289 // retiring the current allocation region) 290 // We need to clear and set the cached recorded/cached collection set 291 // information in the heap region here (before the region gets added 292 // to the collection set). An individual heap region's cached values 293 // are calculated, aggregated with the policy collection set info, 294 // and cached in the heap region here (initially) and (subsequently) 295 // by the Young List sampling code. 296 // Ignore calls to this due to retirement during full gc. 297 298 if (!_g1h->collector_state()->in_full_gc()) { 299 size_t rs_length = hr->rem_set()->occupied(); 300 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr); 301 302 // Cache the values we have added to the aggregated information 303 // in the heap region in case we have to remove this region from 304 // the incremental collection set, or it is updated by the 305 // rset sampling code 306 hr->set_recorded_rs_length(rs_length); 307 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms); 308 309 _inc_recorded_rs_lengths += rs_length; 310 _inc_predicted_elapsed_time_ms += region_elapsed_time_ms; 311 _inc_bytes_used_before += hr->used(); 312 } 313 314 assert(!hr->in_collection_set(), "invariant"); 315 _g1h->register_young_region_with_cset(hr); 316 } 317 318 void G1CollectionSet::add_survivor_regions(HeapRegion* hr) { 319 assert(hr->is_survivor(), "Must only add survivor regions, but is %s", hr->get_type_str()); 320 add_young_region_common(hr); 321 } 322 323 void G1CollectionSet::add_eden_region(HeapRegion* hr) { 324 assert(hr->is_eden(), "Must only add eden regions, but is %s", hr->get_type_str()); 325 add_young_region_common(hr); 326 } 327 328 #ifndef PRODUCT 329 class G1VerifyYoungAgesClosure : public HeapRegionClosure { 330 public: 331 bool _valid; 332 public: 333 G1VerifyYoungAgesClosure() : HeapRegionClosure(), _valid(true) { } 334 335 virtual bool do_heap_region(HeapRegion* r) { 336 guarantee(r->is_young(), "Region must be young but is %s", r->get_type_str()); 337 338 SurvRateGroup* group = r->surv_rate_group(); 339 340 if (group == NULL) { 341 log_error(gc, verify)("## encountered NULL surv_rate_group in young region"); 342 _valid = false; 343 } 344 345 if (r->age_in_surv_rate_group() < 0) { 346 log_error(gc, verify)("## encountered negative age in young region"); 347 _valid = false; 348 } 349 350 return false; 351 } 352 353 bool valid() const { return _valid; } 354 }; 355 356 bool G1CollectionSet::verify_young_ages() { 357 assert_at_safepoint_on_vm_thread(); 358 359 G1VerifyYoungAgesClosure cl; 360 iterate(&cl); 361 362 if (!cl.valid()) { 363 LogStreamHandle(Error, gc, verify) log; 364 print(&log); 365 } 366 367 return cl.valid(); 368 } 369 370 class G1PrintCollectionSetDetailClosure : public HeapRegionClosure { 371 outputStream* _st; 372 public: 373 G1PrintCollectionSetDetailClosure(outputStream* st) : HeapRegionClosure(), _st(st) { } 374 375 virtual bool do_heap_region(HeapRegion* r) { 376 assert(r->in_collection_set(), "Region %u should be in collection set", r->hrm_index()); 377 _st->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d", 378 HR_FORMAT_PARAMS(r), 379 p2i(r->prev_top_at_mark_start()), 380 p2i(r->next_top_at_mark_start()), 381 r->age_in_surv_rate_group_cond()); 382 return false; 383 } 384 }; 385 386 void G1CollectionSet::print(outputStream* st) { 387 st->print_cr("\nCollection_set:"); 388 389 G1PrintCollectionSetDetailClosure cl(st); 390 iterate(&cl); 391 } 392 #endif // !PRODUCT 393 394 double G1CollectionSet::finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors) { 395 double young_start_time_sec = os::elapsedTime(); 396 397 finalize_incremental_building(); 398 399 guarantee(target_pause_time_ms > 0.0, 400 "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms); 401 402 size_t pending_cards = _policy->pending_cards(); 403 double base_time_ms = _policy->predict_base_elapsed_time_ms(pending_cards); 404 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0); 405 406 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", 407 pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms); 408 409 // The young list is laid with the survivor regions from the previous 410 // pause are appended to the RHS of the young list, i.e. 411 // [Newly Young Regions ++ Survivors from last pause]. 412 413 uint survivor_region_length = survivors->length(); 414 uint eden_region_length = _g1h->eden_regions_count(); 415 init_region_lengths(eden_region_length, survivor_region_length); 416 417 verify_young_cset_indices(); 418 419 // Clear the fields that point to the survivor list - they are all young now. 420 survivors->convert_to_eden(); 421 422 _bytes_used_before = _inc_bytes_used_before; 423 time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0); 424 425 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", 426 eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms); 427 428 // The number of recorded young regions is the incremental 429 // collection set's current size 430 set_recorded_rs_lengths(_inc_recorded_rs_lengths); 431 432 double young_end_time_sec = os::elapsedTime(); 433 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0); 434 435 return time_remaining_ms; 436 } 437 438 void G1CollectionSet::add_as_old(HeapRegion* hr) { 439 cset_chooser()->pop(); // already have region via peek() 440 _g1h->old_set_remove(hr); 441 add_old_region(hr); 442 } 443 444 void G1CollectionSet::add_as_optional(HeapRegion* hr) { 445 assert(_optional_regions != NULL, "Must not be called before array is allocated"); 446 cset_chooser()->pop(); // already have region via peek() 447 _g1h->old_set_remove(hr); 448 add_optional_region(hr); 449 } 450 451 bool G1CollectionSet::optional_is_full() { 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 cset_chooser()->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 = cset_chooser()->peek(); 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 = cset_chooser()->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 = cset_chooser()->peek(); 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 cset_chooser()->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 630 // chooser 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 g1h->old_set_add(hr); 634 g1h->clear_in_cset(hr); 635 hr->set_index_in_opt_cset(InvalidCSetIndex); 636 _cset->cset_chooser()->push(hr); 637 } 638 _cset->free_optional_regions(); 639 } 640 641 uint G1OptionalCSet::size() { 642 return _cset->optional_region_length() - _current_index; 643 } 644 645 bool G1OptionalCSet::is_empty() { 646 return size() == 0; 647 } 648 649 void G1OptionalCSet::prepare_to_evacuate_optional_region(HeapRegion* hr) { 650 log_trace(gc, cset)("Adding region %u for optional evacuation", hr->hrm_index()); 651 G1CollectedHeap::heap()->clear_in_cset(hr); 652 _cset->add_old_region(hr); 653 } 654 655 #ifdef ASSERT 656 class G1VerifyYoungCSetIndicesClosure : public HeapRegionClosure { 657 private: 658 size_t _young_length; 659 int* _heap_region_indices; 660 public: 661 G1VerifyYoungCSetIndicesClosure(size_t young_length) : HeapRegionClosure(), _young_length(young_length) { 662 _heap_region_indices = NEW_C_HEAP_ARRAY(int, young_length, mtGC); 663 for (size_t i = 0; i < young_length; i++) { 664 _heap_region_indices[i] = -1; 665 } 666 } 667 ~G1VerifyYoungCSetIndicesClosure() { 668 FREE_C_HEAP_ARRAY(int, _heap_region_indices); 669 } 670 671 virtual bool do_heap_region(HeapRegion* r) { 672 const int idx = r->young_index_in_cset(); 673 674 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()); 675 assert((size_t)idx < _young_length, "Young cset index too large for region %u", r->hrm_index()); 676 677 assert(_heap_region_indices[idx] == -1, 678 "Index %d used by multiple regions, first use by region %u, second by region %u", 679 idx, _heap_region_indices[idx], r->hrm_index()); 680 681 _heap_region_indices[idx] = r->hrm_index(); 682 683 return false; 684 } 685 }; 686 687 void G1CollectionSet::verify_young_cset_indices() const { 688 assert_at_safepoint_on_vm_thread(); 689 690 G1VerifyYoungCSetIndicesClosure cl(_collection_set_cur_length); 691 iterate(&cl); 692 } 693 #endif