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/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 CollectionSetChooser* G1CollectionSet::cset_chooser() { 48 return _cset_chooser; 49 } 50 51 double G1CollectionSet::predict_region_elapsed_time_ms(HeapRegion* hr) { 52 return _policy->predict_region_elapsed_time_ms(hr, collector_state()->in_young_only_phase()); 53 } 54 55 G1CollectionSet::G1CollectionSet(G1CollectedHeap* g1h, G1Policy* policy) : 56 _g1h(g1h), 57 _policy(policy), 58 _cset_chooser(new CollectionSetChooser()), 59 _eden_region_length(0), 60 _survivor_region_length(0), 61 _old_region_length(0), 62 _collection_set_regions(NULL), 63 _collection_set_cur_length(0), 64 _collection_set_max_length(0), 65 _optional_regions(NULL), 66 _optional_region_length(0), 67 _optional_region_max_length(0), 68 _bytes_used_before(0), 69 _recorded_rs_lengths(0), 70 _inc_build_state(Inactive), 71 _inc_bytes_used_before(0), 72 _inc_recorded_rs_lengths(0), 73 _inc_recorded_rs_lengths_diffs(0), 74 _inc_predicted_elapsed_time_ms(0.0), 75 _inc_predicted_elapsed_time_ms_diffs(0.0) { 76 } 77 78 G1CollectionSet::~G1CollectionSet() { 79 if (_collection_set_regions != NULL) { 80 FREE_C_HEAP_ARRAY(uint, _collection_set_regions); 81 } 82 free_optional_regions(); 83 delete _cset_chooser; 84 } 85 86 void G1CollectionSet::init_region_lengths(uint eden_cset_region_length, 87 uint survivor_cset_region_length) { 88 assert_at_safepoint_on_vm_thread(); 89 90 _eden_region_length = eden_cset_region_length; 91 _survivor_region_length = survivor_cset_region_length; 92 93 assert((size_t) young_region_length() == _collection_set_cur_length, 94 "Young region length %u should match collection set length " SIZE_FORMAT, young_region_length(), _collection_set_cur_length); 95 96 _old_region_length = 0; 97 _optional_region_length = 0; 98 } 99 100 void G1CollectionSet::initialize(uint max_region_length) { 101 guarantee(_collection_set_regions == NULL, "Must only initialize once."); 102 _collection_set_max_length = max_region_length; 103 _collection_set_regions = NEW_C_HEAP_ARRAY(uint, max_region_length, mtGC); 104 } 105 106 void G1CollectionSet::initialize_optional(uint max_length) { 107 assert(_optional_regions == NULL, "Already initialized"); 108 assert(_optional_region_length == 0, "Already initialized"); 109 assert(_optional_region_max_length == 0, "Already initialized"); 110 _optional_region_max_length = max_length; 111 _optional_regions = NEW_C_HEAP_ARRAY(HeapRegion*, _optional_region_max_length, mtGC); 112 } 113 114 void G1CollectionSet::free_optional_regions() { 115 _optional_region_length = 0; 116 _optional_region_max_length = 0; 117 if (_optional_regions != NULL) { 118 FREE_C_HEAP_ARRAY(HeapRegion*, _optional_regions); 119 _optional_regions = NULL; 120 } 121 } 122 123 void G1CollectionSet::set_recorded_rs_lengths(size_t rs_lengths) { 124 _recorded_rs_lengths = rs_lengths; 125 } 126 127 // Add the heap region at the head of the non-incremental collection set 128 void G1CollectionSet::add_old_region(HeapRegion* hr) { 129 assert_at_safepoint_on_vm_thread(); 130 131 assert(_inc_build_state == Active || hr->index_in_opt_cset() != G1OptionalCSet::InvalidCSetIndex, 132 "Precondition, actively building cset or adding optional later on"); 133 assert(hr->is_old(), "the region should be old"); 134 135 assert(!hr->in_collection_set(), "should not already be in the CSet"); 136 _g1h->register_old_region_with_cset(hr); 137 138 _collection_set_regions[_collection_set_cur_length++] = hr->hrm_index(); 139 assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set now larger than maximum size."); 140 141 _bytes_used_before += hr->used(); 142 size_t rs_length = hr->rem_set()->occupied(); 143 _recorded_rs_lengths += rs_length; 144 _old_region_length += 1; 145 146 log_trace(gc, cset)("Added old region %d to collection set", hr->hrm_index()); 147 } 148 149 void G1CollectionSet::add_optional_region(HeapRegion* hr) { 150 assert(!optional_is_full(), "Precondition, must have room left for this region"); 151 assert(hr->is_old(), "the region should be old"); 152 assert(!hr->in_collection_set(), "should not already be in the CSet"); 153 154 _g1h->register_optional_region_with_cset(hr); 155 156 _optional_regions[_optional_region_length] = hr; 157 uint index = _optional_region_length++; 158 hr->set_index_in_opt_cset(index); 159 160 log_trace(gc, cset)("Added region %d to optional collection set (%u)", hr->hrm_index(), _optional_region_length); 161 } 162 163 // Initialize the per-collection-set information 164 void G1CollectionSet::start_incremental_building() { 165 assert(_collection_set_cur_length == 0, "Collection set must be empty before starting a new collection set."); 166 assert(_inc_build_state == Inactive, "Precondition"); 167 168 _inc_bytes_used_before = 0; 169 170 _inc_recorded_rs_lengths = 0; 171 _inc_recorded_rs_lengths_diffs = 0; 172 _inc_predicted_elapsed_time_ms = 0.0; 173 _inc_predicted_elapsed_time_ms_diffs = 0.0; 174 _inc_build_state = Active; 175 } 176 177 void G1CollectionSet::finalize_incremental_building() { 178 assert(_inc_build_state == Active, "Precondition"); 179 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint"); 180 181 // The two "main" fields, _inc_recorded_rs_lengths and 182 // _inc_predicted_elapsed_time_ms, are updated by the thread 183 // that adds a new region to the CSet. Further updates by the 184 // concurrent refinement thread that samples the young RSet lengths 185 // are accumulated in the *_diffs fields. Here we add the diffs to 186 // the "main" fields. 187 188 if (_inc_recorded_rs_lengths_diffs >= 0) { 189 _inc_recorded_rs_lengths += _inc_recorded_rs_lengths_diffs; 190 } else { 191 // This is defensive. The diff should in theory be always positive 192 // as RSets can only grow between GCs. However, given that we 193 // sample their size concurrently with other threads updating them 194 // it's possible that we might get the wrong size back, which 195 // could make the calculations somewhat inaccurate. 196 size_t diffs = (size_t) (-_inc_recorded_rs_lengths_diffs); 197 if (_inc_recorded_rs_lengths >= diffs) { 198 _inc_recorded_rs_lengths -= diffs; 199 } else { 200 _inc_recorded_rs_lengths = 0; 201 } 202 } 203 _inc_predicted_elapsed_time_ms += _inc_predicted_elapsed_time_ms_diffs; 204 205 _inc_recorded_rs_lengths_diffs = 0; 206 _inc_predicted_elapsed_time_ms_diffs = 0.0; 207 } 208 209 void G1CollectionSet::clear() { 210 assert_at_safepoint_on_vm_thread(); 211 _collection_set_cur_length = 0; 212 _optional_region_length = 0; 213 } 214 215 void G1CollectionSet::iterate(HeapRegionClosure* cl) const { 216 iterate_from(cl, 0, 1); 217 } 218 219 void G1CollectionSet::iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const { 220 size_t len = _collection_set_cur_length; 221 OrderAccess::loadload(); 222 if (len == 0) { 223 return; 224 } 225 size_t start_pos = (worker_id * len) / total_workers; 226 size_t cur_pos = start_pos; 227 228 do { 229 HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos]); 230 bool result = cl->do_heap_region(r); 231 if (result) { 232 cl->set_incomplete(); 233 return; 234 } 235 cur_pos++; 236 if (cur_pos == len) { 237 cur_pos = 0; 238 } 239 } while (cur_pos != start_pos); 240 } 241 242 void G1CollectionSet::update_young_region_prediction(HeapRegion* hr, 243 size_t new_rs_length) { 244 // Update the CSet information that is dependent on the new RS length 245 assert(hr->is_young(), "Precondition"); 246 assert(!SafepointSynchronize::is_at_safepoint(), "should not be at a safepoint"); 247 248 // We could have updated _inc_recorded_rs_lengths and 249 // _inc_predicted_elapsed_time_ms directly but we'd need to do 250 // that atomically, as this code is executed by a concurrent 251 // refinement thread, potentially concurrently with a mutator thread 252 // allocating a new region and also updating the same fields. To 253 // avoid the atomic operations we accumulate these updates on two 254 // separate fields (*_diffs) and we'll just add them to the "main" 255 // fields at the start of a GC. 256 257 ssize_t old_rs_length = (ssize_t) hr->recorded_rs_length(); 258 ssize_t rs_lengths_diff = (ssize_t) new_rs_length - old_rs_length; 259 _inc_recorded_rs_lengths_diffs += rs_lengths_diff; 260 261 double old_elapsed_time_ms = hr->predicted_elapsed_time_ms(); 262 double new_region_elapsed_time_ms = predict_region_elapsed_time_ms(hr); 263 double elapsed_ms_diff = new_region_elapsed_time_ms - old_elapsed_time_ms; 264 _inc_predicted_elapsed_time_ms_diffs += elapsed_ms_diff; 265 266 hr->set_recorded_rs_length(new_rs_length); 267 hr->set_predicted_elapsed_time_ms(new_region_elapsed_time_ms); 268 } 269 270 void G1CollectionSet::add_young_region_common(HeapRegion* hr) { 271 assert(hr->is_young(), "invariant"); 272 assert(_inc_build_state == Active, "Precondition"); 273 274 size_t collection_set_length = _collection_set_cur_length; 275 assert(collection_set_length <= INT_MAX, "Collection set is too large with %d entries", (int)collection_set_length); 276 hr->set_young_index_in_cset((int)collection_set_length); 277 278 _collection_set_regions[collection_set_length] = hr->hrm_index(); 279 // Concurrent readers must observe the store of the value in the array before an 280 // update to the length field. 281 OrderAccess::storestore(); 282 _collection_set_cur_length++; 283 assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set larger than maximum allowed."); 284 285 // This routine is used when: 286 // * adding survivor regions to the incremental cset at the end of an 287 // evacuation pause or 288 // * adding the current allocation region to the incremental cset 289 // when it is retired. 290 // Therefore this routine may be called at a safepoint by the 291 // VM thread, or in-between safepoints by mutator threads (when 292 // retiring the current allocation region) 293 // We need to clear and set the cached recorded/cached collection set 294 // information in the heap region here (before the region gets added 295 // to the collection set). An individual heap region's cached values 296 // are calculated, aggregated with the policy collection set info, 297 // and cached in the heap region here (initially) and (subsequently) 298 // by the Young List sampling code. 299 // Ignore calls to this due to retirement during full gc. 300 301 if (!_g1h->collector_state()->in_full_gc()) { 302 size_t rs_length = hr->rem_set()->occupied(); 303 double region_elapsed_time_ms = predict_region_elapsed_time_ms(hr); 304 305 // Cache the values we have added to the aggregated information 306 // in the heap region in case we have to remove this region from 307 // the incremental collection set, or it is updated by the 308 // rset sampling code 309 hr->set_recorded_rs_length(rs_length); 310 hr->set_predicted_elapsed_time_ms(region_elapsed_time_ms); 311 312 _inc_recorded_rs_lengths += rs_length; 313 _inc_predicted_elapsed_time_ms += region_elapsed_time_ms; 314 _inc_bytes_used_before += hr->used(); 315 } 316 317 assert(!hr->in_collection_set(), "invariant"); 318 _g1h->register_young_region_with_cset(hr); 319 } 320 321 void G1CollectionSet::add_survivor_regions(HeapRegion* hr) { 322 assert(hr->is_survivor(), "Must only add survivor regions, but is %s", hr->get_type_str()); 323 add_young_region_common(hr); 324 } 325 326 void G1CollectionSet::add_eden_region(HeapRegion* hr) { 327 assert(hr->is_eden(), "Must only add eden regions, but is %s", hr->get_type_str()); 328 add_young_region_common(hr); 329 } 330 331 #ifndef PRODUCT 332 class G1VerifyYoungAgesClosure : public HeapRegionClosure { 333 public: 334 bool _valid; 335 public: 336 G1VerifyYoungAgesClosure() : HeapRegionClosure(), _valid(true) { } 337 338 virtual bool do_heap_region(HeapRegion* r) { 339 guarantee(r->is_young(), "Region must be young but is %s", r->get_type_str()); 340 341 SurvRateGroup* group = r->surv_rate_group(); 342 343 if (group == NULL) { 344 log_error(gc, verify)("## encountered NULL surv_rate_group in young region"); 345 _valid = false; 346 } 347 348 if (r->age_in_surv_rate_group() < 0) { 349 log_error(gc, verify)("## encountered negative age in young region"); 350 _valid = false; 351 } 352 353 return false; 354 } 355 356 bool valid() const { return _valid; } 357 }; 358 359 bool G1CollectionSet::verify_young_ages() { 360 assert_at_safepoint_on_vm_thread(); 361 362 G1VerifyYoungAgesClosure cl; 363 iterate(&cl); 364 365 if (!cl.valid()) { 366 LogStreamHandle(Error, gc, verify) log; 367 print(&log); 368 } 369 370 return cl.valid(); 371 } 372 373 class G1PrintCollectionSetDetailClosure : public HeapRegionClosure { 374 outputStream* _st; 375 public: 376 G1PrintCollectionSetDetailClosure(outputStream* st) : HeapRegionClosure(), _st(st) { } 377 378 virtual bool do_heap_region(HeapRegion* r) { 379 assert(r->in_collection_set(), "Region %u should be in collection set", r->hrm_index()); 380 _st->print_cr(" " HR_FORMAT ", P: " PTR_FORMAT "N: " PTR_FORMAT ", age: %4d", 381 HR_FORMAT_PARAMS(r), 382 p2i(r->prev_top_at_mark_start()), 383 p2i(r->next_top_at_mark_start()), 384 r->age_in_surv_rate_group_cond()); 385 return false; 386 } 387 }; 388 389 void G1CollectionSet::print(outputStream* st) { 390 st->print_cr("\nCollection_set:"); 391 392 G1PrintCollectionSetDetailClosure cl(st); 393 iterate(&cl); 394 } 395 #endif // !PRODUCT 396 397 double G1CollectionSet::finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors) { 398 double young_start_time_sec = os::elapsedTime(); 399 400 finalize_incremental_building(); 401 402 guarantee(target_pause_time_ms > 0.0, 403 "target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms); 404 405 size_t pending_cards = _policy->pending_cards(); 406 double base_time_ms = _policy->predict_base_elapsed_time_ms(pending_cards); 407 double time_remaining_ms = MAX2(target_pause_time_ms - base_time_ms, 0.0); 408 409 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", 410 pending_cards, base_time_ms, time_remaining_ms, target_pause_time_ms); 411 412 // The young list is laid with the survivor regions from the previous 413 // pause are appended to the RHS of the young list, i.e. 414 // [Newly Young Regions ++ Survivors from last pause]. 415 416 uint survivor_region_length = survivors->length(); 417 uint eden_region_length = _g1h->eden_regions_count(); 418 init_region_lengths(eden_region_length, survivor_region_length); 419 420 verify_young_cset_indices(); 421 422 // Clear the fields that point to the survivor list - they are all young now. 423 survivors->convert_to_eden(); 424 425 _bytes_used_before = _inc_bytes_used_before; 426 time_remaining_ms = MAX2(time_remaining_ms - _inc_predicted_elapsed_time_ms, 0.0); 427 428 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", 429 eden_region_length, survivor_region_length, _inc_predicted_elapsed_time_ms, target_pause_time_ms); 430 431 // The number of recorded young regions is the incremental 432 // collection set's current size 433 set_recorded_rs_lengths(_inc_recorded_rs_lengths); 434 435 double young_end_time_sec = os::elapsedTime(); 436 phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0); 437 438 return time_remaining_ms; 439 } 440 441 void G1CollectionSet::add_as_old(HeapRegion* hr) { 442 cset_chooser()->pop(); // already have region via peek() 443 _g1h->old_set_remove(hr); 444 add_old_region(hr); 445 } 446 447 void G1CollectionSet::add_as_optional(HeapRegion* hr) { 448 assert(_optional_regions != NULL, "Must not be called before array is allocated"); 449 cset_chooser()->pop(); // already have region via peek() 450 _g1h->old_set_remove(hr); 451 add_optional_region(hr); 452 } 453 454 bool G1CollectionSet::optional_is_full() { 455 assert(_optional_region_length <= _optional_region_max_length, "Invariant"); 456 return _optional_region_length == _optional_region_max_length; 457 } 458 459 void G1CollectionSet::clear_optional_region(const HeapRegion* hr) { 460 assert(_optional_regions != NULL, "Must not be called before array is allocated"); 461 uint index = hr->index_in_opt_cset(); 462 _optional_regions[index] = NULL; 463 } 464 465 static int compare_region_idx(const uint a, const uint b) { 466 if (a > b) { 467 return 1; 468 } else if (a == b) { 469 return 0; 470 } else { 471 return -1; 472 } 473 } 474 475 void G1CollectionSet::finalize_old_part(double time_remaining_ms) { 476 double non_young_start_time_sec = os::elapsedTime(); 477 double predicted_old_time_ms = 0.0; 478 double predicted_optional_time_ms = 0.0; 479 double optional_threshold_ms = time_remaining_ms * _policy->optional_prediction_fraction(); 480 uint expensive_region_num = 0; 481 482 if (collector_state()->in_mixed_phase()) { 483 cset_chooser()->verify(); 484 const uint min_old_cset_length = _policy->calc_min_old_cset_length(); 485 const uint max_old_cset_length = MAX2(min_old_cset_length, _policy->calc_max_old_cset_length()); 486 bool check_time_remaining = _policy->adaptive_young_list_length(); 487 488 initialize_optional(max_old_cset_length - min_old_cset_length); 489 log_debug(gc, ergo, cset)("Start adding old regions for mixed gc. min %u regions, max %u regions, " 490 "time remaining %1.2fms, optional threshold %1.2fms", 491 min_old_cset_length, max_old_cset_length, time_remaining_ms, optional_threshold_ms); 492 493 HeapRegion* hr = cset_chooser()->peek(); 494 while (hr != NULL) { 495 if (old_region_length() + optional_region_length() >= max_old_cset_length) { 496 // Added maximum number of old regions to the CSet. 497 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached max). " 498 "old %u regions, optional %u regions", 499 old_region_length(), optional_region_length()); 500 break; 501 } 502 503 // Stop adding regions if the remaining reclaimable space is 504 // not above G1HeapWastePercent. 505 size_t reclaimable_bytes = cset_chooser()->remaining_reclaimable_bytes(); 506 double reclaimable_percent = _policy->reclaimable_bytes_percent(reclaimable_bytes); 507 double threshold = (double) G1HeapWastePercent; 508 if (reclaimable_percent <= threshold) { 509 // We've added enough old regions that the amount of uncollected 510 // reclaimable space is at or below the waste threshold. Stop 511 // adding old regions to the CSet. 512 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (reclaimable percentage not over threshold). " 513 "reclaimable: " SIZE_FORMAT "%s (%1.2f%%) threshold: " UINTX_FORMAT "%%", 514 byte_size_in_proper_unit(reclaimable_bytes), proper_unit_for_byte_size(reclaimable_bytes), 515 reclaimable_percent, G1HeapWastePercent); 516 break; 517 } 518 519 double predicted_time_ms = predict_region_elapsed_time_ms(hr); 520 time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0); 521 // Add regions to old set until we reach minimum amount 522 if (old_region_length() < min_old_cset_length) { 523 predicted_old_time_ms += predicted_time_ms; 524 add_as_old(hr); 525 // Record the number of regions added when no time remaining 526 if (time_remaining_ms == 0.0) { 527 expensive_region_num++; 528 } 529 } else { 530 // In the non-auto-tuning case, we'll finish adding regions 531 // to the CSet if we reach the minimum. 532 if (!check_time_remaining) { 533 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached min)."); 534 break; 535 } 536 // Keep adding regions to old set until we reach optional threshold 537 if (time_remaining_ms > optional_threshold_ms) { 538 predicted_old_time_ms += predicted_time_ms; 539 add_as_old(hr); 540 } else if (time_remaining_ms > 0) { 541 // Keep adding optional regions until time is up 542 if (!optional_is_full()) { 543 predicted_optional_time_ms += predicted_time_ms; 544 add_as_optional(hr); 545 } else { 546 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (optional set full)."); 547 break; 548 } 549 } else { 550 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (predicted time is too high)."); 551 break; 552 } 553 } 554 hr = cset_chooser()->peek(); 555 } 556 if (hr == NULL) { 557 log_debug(gc, ergo, cset)("Finish adding old regions to CSet (candidate old regions not available)"); 558 } 559 560 cset_chooser()->verify(); 561 } 562 563 stop_incremental_building(); 564 565 log_debug(gc, ergo, cset)("Finish choosing CSet regions old: %u, optional: %u, " 566 "predicted old time: %1.2fms, predicted optional time: %1.2fms, time remaining: %1.2f", 567 old_region_length(), optional_region_length(), 568 predicted_old_time_ms, predicted_optional_time_ms, time_remaining_ms); 569 if (expensive_region_num > 0) { 570 log_debug(gc, ergo, cset)("CSet contains %u old regions that were added although the predicted time was too high.", 571 expensive_region_num); 572 } 573 574 double non_young_end_time_sec = os::elapsedTime(); 575 phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0); 576 577 QuickSort::sort(_collection_set_regions, _collection_set_cur_length, compare_region_idx, true); 578 } 579 580 HeapRegion* G1OptionalCSet::region_at(uint index) { 581 return _cset->optional_region_at(index); 582 } 583 584 void G1OptionalCSet::prepare_evacuation(double time_limit) { 585 assert(_current_index == _current_limit, "Before prepare no regions should be ready for evac"); 586 587 uint prepared_regions = 0; 588 double prediction_ms = 0; 589 590 _prepare_failed = true; 591 for (uint i = _current_index; i < _cset->optional_region_length(); i++) { 592 HeapRegion* hr = region_at(i); 593 prediction_ms += _cset->predict_region_elapsed_time_ms(hr); 594 if (prediction_ms > time_limit) { 595 log_debug(gc, cset)("Prepared %u regions for optional evacuation. Predicted time: %.3fms", prepared_regions, prediction_ms); 596 return; 597 } 598 599 // This region will be included in the next optional evacuation. 600 prepare_to_evacuate_optional_region(hr); 601 prepared_regions++; 602 _current_limit++; 603 _prepare_failed = false; 604 } 605 606 log_debug(gc, cset)("Prepared all %u regions for optional evacuation. Predicted time: %.3fms", 607 prepared_regions, prediction_ms); 608 } 609 610 bool G1OptionalCSet::prepare_failed() { 611 return _prepare_failed; 612 } 613 614 void G1OptionalCSet::complete_evacuation() { 615 _evacuation_failed = false; 616 for (uint i = _current_index; i < _current_limit; i++) { 617 HeapRegion* hr = region_at(i); 618 _cset->clear_optional_region(hr); 619 if (hr->evacuation_failed()){ 620 _evacuation_failed = true; 621 } 622 } 623 _current_index = _current_limit; 624 } 625 626 bool G1OptionalCSet::evacuation_failed() { 627 return _evacuation_failed; 628 } 629 630 G1OptionalCSet::~G1OptionalCSet() { 631 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 632 while (!is_empty()) { 633 // We want to return regions not evacuated to the 634 // chooser in reverse order to maintain the old order. 635 HeapRegion* hr = _cset->remove_last_optional_region(); 636 assert(hr != NULL, "Should be valid region left"); 637 _pset->free_unused_optional_region(hr); 638 g1h->old_set_add(hr); 639 g1h->clear_in_cset(hr); 640 hr->set_index_in_opt_cset(InvalidCSetIndex); 641 _cset->cset_chooser()->push(hr); 642 } 643 _cset->free_optional_regions(); 644 } 645 646 uint G1OptionalCSet::size() { 647 return _cset->optional_region_length() - _current_index; 648 } 649 650 bool G1OptionalCSet::is_empty() { 651 return size() == 0; 652 } 653 654 void G1OptionalCSet::prepare_to_evacuate_optional_region(HeapRegion* hr) { 655 log_trace(gc, cset)("Adding region %u for optional evacuation", hr->hrm_index()); 656 G1CollectedHeap::heap()->clear_in_cset(hr); 657 _cset->add_old_region(hr); 658 } 659 660 #ifdef ASSERT 661 class G1VerifyYoungCSetIndicesClosure : public HeapRegionClosure { 662 private: 663 size_t _young_length; 664 int* _heap_region_indices; 665 public: 666 G1VerifyYoungCSetIndicesClosure(size_t young_length) : HeapRegionClosure(), _young_length(young_length) { 667 _heap_region_indices = NEW_C_HEAP_ARRAY(int, young_length, mtGC); 668 for (size_t i = 0; i < young_length; i++) { 669 _heap_region_indices[i] = -1; 670 } 671 } 672 ~G1VerifyYoungCSetIndicesClosure() { 673 FREE_C_HEAP_ARRAY(int, _heap_region_indices); 674 } 675 676 virtual bool do_heap_region(HeapRegion* r) { 677 const int idx = r->young_index_in_cset(); 678 679 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()); 680 assert((size_t)idx < _young_length, "Young cset index too large for region %u", r->hrm_index()); 681 682 assert(_heap_region_indices[idx] == -1, 683 "Index %d used by multiple regions, first use by region %u, second by region %u", 684 idx, _heap_region_indices[idx], r->hrm_index()); 685 686 _heap_region_indices[idx] = r->hrm_index(); 687 688 return false; 689 } 690 }; 691 692 void G1CollectionSet::verify_young_cset_indices() const { 693 assert_at_safepoint_on_vm_thread(); 694 695 G1VerifyYoungCSetIndicesClosure cl(_collection_set_cur_length); 696 iterate(&cl); 697 } 698 #endif