1 /* 2 * Copyright (c) 2001, 2015, 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 "classfile/stringTable.hpp" 27 #include "classfile/symbolTable.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "code/codeCache.hpp" 30 #include "gc/parallel/parallelScavengeHeap.hpp" 31 #include "gc/parallel/psAdaptiveSizePolicy.hpp" 32 #include "gc/parallel/psMarkSweep.hpp" 33 #include "gc/parallel/psMarkSweepDecorator.hpp" 34 #include "gc/parallel/psOldGen.hpp" 35 #include "gc/parallel/psScavenge.hpp" 36 #include "gc/parallel/psYoungGen.hpp" 37 #include "gc/serial/markSweep.hpp" 38 #include "gc/shared/gcCause.hpp" 39 #include "gc/shared/gcHeapSummary.hpp" 40 #include "gc/shared/gcId.hpp" 41 #include "gc/shared/gcLocker.inline.hpp" 42 #include "gc/shared/gcTimer.hpp" 43 #include "gc/shared/gcTrace.hpp" 44 #include "gc/shared/gcTraceTime.inline.hpp" 45 #include "gc/shared/isGCActiveMark.hpp" 46 #include "gc/shared/referencePolicy.hpp" 47 #include "gc/shared/referenceProcessor.hpp" 48 #include "gc/shared/spaceDecorator.hpp" 49 #include "logging/log.hpp" 50 #include "oops/oop.inline.hpp" 51 #include "runtime/biasedLocking.hpp" 52 #include "runtime/fprofiler.hpp" 53 #include "runtime/safepoint.hpp" 54 #include "runtime/vmThread.hpp" 55 #include "services/management.hpp" 56 #include "services/memoryService.hpp" 57 #include "utilities/events.hpp" 58 #include "utilities/stack.inline.hpp" 59 60 elapsedTimer PSMarkSweep::_accumulated_time; 61 jlong PSMarkSweep::_time_of_last_gc = 0; 62 CollectorCounters* PSMarkSweep::_counters = NULL; 63 64 void PSMarkSweep::initialize() { 65 MemRegion mr = ParallelScavengeHeap::heap()->reserved_region(); 66 set_ref_processor(new ReferenceProcessor(mr)); // a vanilla ref proc 67 _counters = new CollectorCounters("PSMarkSweep", 1); 68 } 69 70 // This method contains all heap specific policy for invoking mark sweep. 71 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact 72 // the heap. It will do nothing further. If we need to bail out for policy 73 // reasons, scavenge before full gc, or any other specialized behavior, it 74 // needs to be added here. 75 // 76 // Note that this method should only be called from the vm_thread while 77 // at a safepoint! 78 // 79 // Note that the all_soft_refs_clear flag in the collector policy 80 // may be true because this method can be called without intervening 81 // activity. For example when the heap space is tight and full measure 82 // are being taken to free space. 83 84 void PSMarkSweep::invoke(bool maximum_heap_compaction) { 85 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 86 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); 87 assert(!ParallelScavengeHeap::heap()->is_gc_active(), "not reentrant"); 88 89 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 90 GCCause::Cause gc_cause = heap->gc_cause(); 91 PSAdaptiveSizePolicy* policy = heap->size_policy(); 92 IsGCActiveMark mark; 93 94 if (ScavengeBeforeFullGC) { 95 PSScavenge::invoke_no_policy(); 96 } 97 98 const bool clear_all_soft_refs = 99 heap->collector_policy()->should_clear_all_soft_refs(); 100 101 uint count = maximum_heap_compaction ? 1 : MarkSweepAlwaysCompactCount; 102 UIntXFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); 103 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); 104 } 105 106 // This method contains no policy. You should probably 107 // be calling invoke() instead. 108 bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { 109 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); 110 assert(ref_processor() != NULL, "Sanity"); 111 112 if (GC_locker::check_active_before_gc()) { 113 return false; 114 } 115 116 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 117 GCCause::Cause gc_cause = heap->gc_cause(); 118 119 GCIdMark gc_id_mark; 120 _gc_timer->register_gc_start(); 121 _gc_tracer->report_gc_start(gc_cause, _gc_timer->gc_start()); 122 123 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); 124 125 // The scope of casr should end after code that can change 126 // CollectorPolicy::_should_clear_all_soft_refs. 127 ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); 128 129 PSYoungGen* young_gen = heap->young_gen(); 130 PSOldGen* old_gen = heap->old_gen(); 131 132 // Increment the invocation count 133 heap->increment_total_collections(true /* full */); 134 135 // Save information needed to minimize mangling 136 heap->record_gen_tops_before_GC(); 137 138 // We need to track unique mark sweep invocations as well. 139 _total_invocations++; 140 141 heap->print_heap_before_gc(); 142 heap->trace_heap_before_gc(_gc_tracer); 143 144 // Fill in TLABs 145 heap->accumulate_statistics_all_tlabs(); 146 heap->ensure_parsability(true); // retire TLABs 147 148 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { 149 HandleMark hm; // Discard invalid handles created during verification 150 Universe::verify("Before GC"); 151 } 152 153 // Verify object start arrays 154 if (VerifyObjectStartArray && 155 VerifyBeforeGC) { 156 old_gen->verify_object_start_array(); 157 } 158 159 heap->pre_full_gc_dump(_gc_timer); 160 161 // Filled in below to track the state of the young gen after the collection. 162 bool eden_empty; 163 bool survivors_empty; 164 bool young_gen_empty; 165 166 { 167 HandleMark hm; 168 169 GCTraceCPUTime tcpu; 170 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause, true); 171 TraceCollectorStats tcs(counters()); 172 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); 173 174 if (TraceOldGenTime) accumulated_time()->start(); 175 176 // Let the size policy know we're starting 177 size_policy->major_collection_begin(); 178 179 CodeCache::gc_prologue(); 180 BiasedLocking::preserve_marks(); 181 182 // Capture metadata size before collection for sizing. 183 size_t metadata_prev_used = MetaspaceAux::used_bytes(); 184 185 size_t old_gen_prev_used = old_gen->used_in_bytes(); 186 size_t young_gen_prev_used = young_gen->used_in_bytes(); 187 188 allocate_stacks(); 189 190 #if defined(COMPILER2) || INCLUDE_JVMCI 191 DerivedPointerTable::clear(); 192 #endif 193 194 ref_processor()->enable_discovery(); 195 ref_processor()->setup_policy(clear_all_softrefs); 196 197 mark_sweep_phase1(clear_all_softrefs); 198 199 mark_sweep_phase2(); 200 201 #if defined(COMPILER2) || INCLUDE_JVMCI 202 // Don't add any more derived pointers during phase3 203 assert(DerivedPointerTable::is_active(), "Sanity"); 204 DerivedPointerTable::set_active(false); 205 #endif 206 207 mark_sweep_phase3(); 208 209 mark_sweep_phase4(); 210 211 restore_marks(); 212 213 deallocate_stacks(); 214 215 if (ZapUnusedHeapArea) { 216 // Do a complete mangle (top to end) because the usage for 217 // scratch does not maintain a top pointer. 218 young_gen->to_space()->mangle_unused_area_complete(); 219 } 220 221 eden_empty = young_gen->eden_space()->is_empty(); 222 if (!eden_empty) { 223 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); 224 } 225 226 // Update heap occupancy information which is used as 227 // input to soft ref clearing policy at the next gc. 228 Universe::update_heap_info_at_gc(); 229 230 survivors_empty = young_gen->from_space()->is_empty() && 231 young_gen->to_space()->is_empty(); 232 young_gen_empty = eden_empty && survivors_empty; 233 234 ModRefBarrierSet* modBS = barrier_set_cast<ModRefBarrierSet>(heap->barrier_set()); 235 MemRegion old_mr = heap->old_gen()->reserved(); 236 if (young_gen_empty) { 237 modBS->clear(MemRegion(old_mr.start(), old_mr.end())); 238 } else { 239 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end())); 240 } 241 242 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 243 ClassLoaderDataGraph::purge(); 244 MetaspaceAux::verify_metrics(); 245 246 BiasedLocking::restore_marks(); 247 CodeCache::gc_epilogue(); 248 JvmtiExport::gc_epilogue(); 249 250 #if defined(COMPILER2) || INCLUDE_JVMCI 251 DerivedPointerTable::update_pointers(); 252 #endif 253 254 ref_processor()->enqueue_discovered_references(NULL); 255 256 // Update time of last GC 257 reset_millis_since_last_gc(); 258 259 // Let the size policy know we're done 260 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); 261 262 if (UseAdaptiveSizePolicy) { 263 264 log_debug(gc, ergo)("AdaptiveSizeStart: collection: %d ", heap->total_collections()); 265 log_trace(gc, ergo)("old_gen_capacity: " SIZE_FORMAT " young_gen_capacity: " SIZE_FORMAT, 266 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes()); 267 268 // Don't check if the size_policy is ready here. Let 269 // the size_policy check that internally. 270 if (UseAdaptiveGenerationSizePolicyAtMajorCollection && 271 AdaptiveSizePolicy::should_update_promo_stats(gc_cause)) { 272 // Swap the survivor spaces if from_space is empty. The 273 // resize_young_gen() called below is normally used after 274 // a successful young GC and swapping of survivor spaces; 275 // otherwise, it will fail to resize the young gen with 276 // the current implementation. 277 if (young_gen->from_space()->is_empty()) { 278 young_gen->from_space()->clear(SpaceDecorator::Mangle); 279 young_gen->swap_spaces(); 280 } 281 282 // Calculate optimal free space amounts 283 assert(young_gen->max_size() > 284 young_gen->from_space()->capacity_in_bytes() + 285 young_gen->to_space()->capacity_in_bytes(), 286 "Sizes of space in young gen are out-of-bounds"); 287 288 size_t young_live = young_gen->used_in_bytes(); 289 size_t eden_live = young_gen->eden_space()->used_in_bytes(); 290 size_t old_live = old_gen->used_in_bytes(); 291 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes(); 292 size_t max_old_gen_size = old_gen->max_gen_size(); 293 size_t max_eden_size = young_gen->max_size() - 294 young_gen->from_space()->capacity_in_bytes() - 295 young_gen->to_space()->capacity_in_bytes(); 296 297 // Used for diagnostics 298 size_policy->clear_generation_free_space_flags(); 299 300 size_policy->compute_generations_free_space(young_live, 301 eden_live, 302 old_live, 303 cur_eden, 304 max_old_gen_size, 305 max_eden_size, 306 true /* full gc*/); 307 308 size_policy->check_gc_overhead_limit(young_live, 309 eden_live, 310 max_old_gen_size, 311 max_eden_size, 312 true /* full gc*/, 313 gc_cause, 314 heap->collector_policy()); 315 316 size_policy->decay_supplemental_growth(true /* full gc*/); 317 318 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); 319 320 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), 321 size_policy->calculated_survivor_size_in_bytes()); 322 } 323 log_debug(gc, ergo)("AdaptiveSizeStop: collection: %d ", heap->total_collections()); 324 } 325 326 if (UsePerfData) { 327 heap->gc_policy_counters()->update_counters(); 328 heap->gc_policy_counters()->update_old_capacity( 329 old_gen->capacity_in_bytes()); 330 heap->gc_policy_counters()->update_young_capacity( 331 young_gen->capacity_in_bytes()); 332 } 333 334 heap->resize_all_tlabs(); 335 336 // We collected the heap, recalculate the metaspace capacity 337 MetaspaceGC::compute_new_size(); 338 339 if (TraceOldGenTime) accumulated_time()->stop(); 340 341 young_gen->print_used_change(young_gen_prev_used); 342 old_gen->print_used_change(old_gen_prev_used); 343 MetaspaceAux::print_metaspace_change(metadata_prev_used); 344 345 // Track memory usage and detect low memory 346 MemoryService::track_memory_usage(); 347 heap->update_counters(); 348 } 349 350 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { 351 HandleMark hm; // Discard invalid handles created during verification 352 Universe::verify("After GC"); 353 } 354 355 // Re-verify object start arrays 356 if (VerifyObjectStartArray && 357 VerifyAfterGC) { 358 old_gen->verify_object_start_array(); 359 } 360 361 if (ZapUnusedHeapArea) { 362 old_gen->object_space()->check_mangled_unused_area_complete(); 363 } 364 365 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); 366 367 heap->print_heap_after_gc(); 368 heap->trace_heap_after_gc(_gc_tracer); 369 370 heap->post_full_gc_dump(_gc_timer); 371 372 #ifdef TRACESPINNING 373 ParallelTaskTerminator::print_termination_counts(); 374 #endif 375 376 AdaptiveSizePolicyOutput::print(size_policy, heap->total_collections()); 377 378 _gc_timer->register_gc_end(); 379 380 _gc_tracer->report_gc_end(_gc_timer->gc_end(), _gc_timer->time_partitions()); 381 382 return true; 383 } 384 385 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, 386 PSYoungGen* young_gen, 387 PSOldGen* old_gen) { 388 MutableSpace* const eden_space = young_gen->eden_space(); 389 assert(!eden_space->is_empty(), "eden must be non-empty"); 390 assert(young_gen->virtual_space()->alignment() == 391 old_gen->virtual_space()->alignment(), "alignments do not match"); 392 393 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { 394 return false; 395 } 396 397 // Both generations must be completely committed. 398 if (young_gen->virtual_space()->uncommitted_size() != 0) { 399 return false; 400 } 401 if (old_gen->virtual_space()->uncommitted_size() != 0) { 402 return false; 403 } 404 405 // Figure out how much to take from eden. Include the average amount promoted 406 // in the total; otherwise the next young gen GC will simply bail out to a 407 // full GC. 408 const size_t alignment = old_gen->virtual_space()->alignment(); 409 const size_t eden_used = eden_space->used_in_bytes(); 410 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); 411 const size_t absorb_size = align_size_up(eden_used + promoted, alignment); 412 const size_t eden_capacity = eden_space->capacity_in_bytes(); 413 414 if (absorb_size >= eden_capacity) { 415 return false; // Must leave some space in eden. 416 } 417 418 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; 419 if (new_young_size < young_gen->min_gen_size()) { 420 return false; // Respect young gen minimum size. 421 } 422 423 log_trace(heap, ergo)(" absorbing " SIZE_FORMAT "K: " 424 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " 425 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " 426 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", 427 absorb_size / K, 428 eden_capacity / K, (eden_capacity - absorb_size) / K, 429 young_gen->from_space()->used_in_bytes() / K, 430 young_gen->to_space()->used_in_bytes() / K, 431 young_gen->capacity_in_bytes() / K, new_young_size / K); 432 433 // Fill the unused part of the old gen. 434 MutableSpace* const old_space = old_gen->object_space(); 435 HeapWord* const unused_start = old_space->top(); 436 size_t const unused_words = pointer_delta(old_space->end(), unused_start); 437 438 if (unused_words > 0) { 439 if (unused_words < CollectedHeap::min_fill_size()) { 440 return false; // If the old gen cannot be filled, must give up. 441 } 442 CollectedHeap::fill_with_objects(unused_start, unused_words); 443 } 444 445 // Take the live data from eden and set both top and end in the old gen to 446 // eden top. (Need to set end because reset_after_change() mangles the region 447 // from end to virtual_space->high() in debug builds). 448 HeapWord* const new_top = eden_space->top(); 449 old_gen->virtual_space()->expand_into(young_gen->virtual_space(), 450 absorb_size); 451 young_gen->reset_after_change(); 452 old_space->set_top(new_top); 453 old_space->set_end(new_top); 454 old_gen->reset_after_change(); 455 456 // Update the object start array for the filler object and the data from eden. 457 ObjectStartArray* const start_array = old_gen->start_array(); 458 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { 459 start_array->allocate_block(p); 460 } 461 462 // Could update the promoted average here, but it is not typically updated at 463 // full GCs and the value to use is unclear. Something like 464 // 465 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. 466 467 size_policy->set_bytes_absorbed_from_eden(absorb_size); 468 return true; 469 } 470 471 void PSMarkSweep::allocate_stacks() { 472 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 473 PSYoungGen* young_gen = heap->young_gen(); 474 475 MutableSpace* to_space = young_gen->to_space(); 476 _preserved_marks = (PreservedMark*)to_space->top(); 477 _preserved_count = 0; 478 479 // We want to calculate the size in bytes first. 480 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); 481 // Now divide by the size of a PreservedMark 482 _preserved_count_max /= sizeof(PreservedMark); 483 } 484 485 486 void PSMarkSweep::deallocate_stacks() { 487 _preserved_mark_stack.clear(true); 488 _preserved_oop_stack.clear(true); 489 _marking_stack.clear(); 490 _objarray_stack.clear(true); 491 } 492 493 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { 494 // Recursively traverse all live objects and mark them 495 GCTraceTime(Trace, gc) tm("Phase 1: Mark live objects", _gc_timer); 496 497 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 498 499 // Need to clear claim bits before the tracing starts. 500 ClassLoaderDataGraph::clear_claimed_marks(); 501 502 // General strong roots. 503 { 504 ParallelScavengeHeap::ParStrongRootsScope psrs; 505 Universe::oops_do(mark_and_push_closure()); 506 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles 507 CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure()); 508 MarkingCodeBlobClosure each_active_code_blob(mark_and_push_closure(), !CodeBlobToOopClosure::FixRelocations); 509 Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob); 510 ObjectSynchronizer::oops_do(mark_and_push_closure()); 511 FlatProfiler::oops_do(mark_and_push_closure()); 512 Management::oops_do(mark_and_push_closure()); 513 JvmtiExport::oops_do(mark_and_push_closure()); 514 SystemDictionary::always_strong_oops_do(mark_and_push_closure()); 515 ClassLoaderDataGraph::always_strong_cld_do(follow_cld_closure()); 516 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. 517 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); 518 } 519 520 // Flush marking stack. 521 follow_stack(); 522 523 // Process reference objects found during marking 524 { 525 ref_processor()->setup_policy(clear_all_softrefs); 526 const ReferenceProcessorStats& stats = 527 ref_processor()->process_discovered_references( 528 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL, _gc_timer); 529 gc_tracer()->report_gc_reference_stats(stats); 530 } 531 532 // This is the point where the entire marking should have completed. 533 assert(_marking_stack.is_empty(), "Marking should have completed"); 534 535 // Unload classes and purge the SystemDictionary. 536 bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); 537 538 // Unload nmethods. 539 CodeCache::do_unloading(is_alive_closure(), purged_class); 540 541 // Prune dead klasses from subklass/sibling/implementor lists. 542 Klass::clean_weak_klass_links(is_alive_closure()); 543 544 // Delete entries for dead interned strings. 545 StringTable::unlink(is_alive_closure()); 546 547 // Clean up unreferenced symbols in symbol table. 548 SymbolTable::unlink(); 549 _gc_tracer->report_object_count_after_gc(is_alive_closure()); 550 } 551 552 553 void PSMarkSweep::mark_sweep_phase2() { 554 GCTraceTime(Trace, gc) tm("Phase 2: Compute new object addresses", _gc_timer); 555 556 // Now all live objects are marked, compute the new object addresses. 557 558 // It is not required that we traverse spaces in the same order in 559 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops 560 // tracking expects us to do so. See comment under phase4. 561 562 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 563 PSOldGen* old_gen = heap->old_gen(); 564 565 // Begin compacting into the old gen 566 PSMarkSweepDecorator::set_destination_decorator_tenured(); 567 568 // This will also compact the young gen spaces. 569 old_gen->precompact(); 570 } 571 572 // This should be moved to the shared markSweep code! 573 class PSAlwaysTrueClosure: public BoolObjectClosure { 574 public: 575 bool do_object_b(oop p) { return true; } 576 }; 577 static PSAlwaysTrueClosure always_true; 578 579 void PSMarkSweep::mark_sweep_phase3() { 580 // Adjust the pointers to reflect the new locations 581 GCTraceTime(Trace, gc) tm("Phase 3: Adjust pointers", _gc_timer); 582 583 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 584 PSYoungGen* young_gen = heap->young_gen(); 585 PSOldGen* old_gen = heap->old_gen(); 586 587 // Need to clear claim bits before the tracing starts. 588 ClassLoaderDataGraph::clear_claimed_marks(); 589 590 // General strong roots. 591 Universe::oops_do(adjust_pointer_closure()); 592 JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles 593 CLDToOopClosure adjust_from_cld(adjust_pointer_closure()); 594 Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL); 595 ObjectSynchronizer::oops_do(adjust_pointer_closure()); 596 FlatProfiler::oops_do(adjust_pointer_closure()); 597 Management::oops_do(adjust_pointer_closure()); 598 JvmtiExport::oops_do(adjust_pointer_closure()); 599 SystemDictionary::oops_do(adjust_pointer_closure()); 600 ClassLoaderDataGraph::cld_do(adjust_cld_closure()); 601 602 // Now adjust pointers in remaining weak roots. (All of which should 603 // have been cleared if they pointed to non-surviving objects.) 604 // Global (weak) JNI handles 605 JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure()); 606 607 CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations); 608 CodeCache::blobs_do(&adjust_from_blobs); 609 StringTable::oops_do(adjust_pointer_closure()); 610 ref_processor()->weak_oops_do(adjust_pointer_closure()); 611 PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure()); 612 613 adjust_marks(); 614 615 young_gen->adjust_pointers(); 616 old_gen->adjust_pointers(); 617 } 618 619 void PSMarkSweep::mark_sweep_phase4() { 620 EventMark m("4 compact heap"); 621 GCTraceTime(Trace, gc) tm("Phase 4: Move objects", _gc_timer); 622 623 // All pointers are now adjusted, move objects accordingly 624 625 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 626 PSYoungGen* young_gen = heap->young_gen(); 627 PSOldGen* old_gen = heap->old_gen(); 628 629 old_gen->compact(); 630 young_gen->compact(); 631 } 632 633 jlong PSMarkSweep::millis_since_last_gc() { 634 // We need a monotonically non-decreasing time in ms but 635 // os::javaTimeMillis() does not guarantee monotonicity. 636 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 637 jlong ret_val = now - _time_of_last_gc; 638 // XXX See note in genCollectedHeap::millis_since_last_gc(). 639 if (ret_val < 0) { 640 NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, ret_val);) 641 return 0; 642 } 643 return ret_val; 644 } 645 646 void PSMarkSweep::reset_millis_since_last_gc() { 647 // We need a monotonically non-decreasing time in ms but 648 // os::javaTimeMillis() does not guarantee monotonicity. 649 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 650 }