1 /* 2 * Copyright (c) 2001, 2012, 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/symbolTable.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "code/codeCache.hpp" 29 #include "gc_implementation/parallelScavenge/generationSizer.hpp" 30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp" 31 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp" 32 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp" 33 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp" 34 #include "gc_implementation/parallelScavenge/psOldGen.hpp" 35 #include "gc_implementation/parallelScavenge/psScavenge.hpp" 36 #include "gc_implementation/parallelScavenge/psYoungGen.hpp" 37 #include "gc_implementation/shared/isGCActiveMark.hpp" 38 #include "gc_implementation/shared/markSweep.hpp" 39 #include "gc_implementation/shared/spaceDecorator.hpp" 40 #include "gc_interface/gcCause.hpp" 41 #include "memory/gcLocker.inline.hpp" 42 #include "memory/referencePolicy.hpp" 43 #include "memory/referenceProcessor.hpp" 44 #include "oops/oop.inline.hpp" 45 #include "runtime/biasedLocking.hpp" 46 #include "runtime/fprofiler.hpp" 47 #include "runtime/safepoint.hpp" 48 #include "runtime/vmThread.hpp" 49 #include "services/management.hpp" 50 #include "services/memoryService.hpp" 51 #include "utilities/events.hpp" 52 #include "utilities/stack.inline.hpp" 53 54 elapsedTimer PSMarkSweep::_accumulated_time; 55 jlong PSMarkSweep::_time_of_last_gc = 0; 56 CollectorCounters* PSMarkSweep::_counters = NULL; 57 58 void PSMarkSweep::initialize() { 59 MemRegion mr = Universe::heap()->reserved_region(); 60 _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc 61 _counters = new CollectorCounters("PSMarkSweep", 1); 62 } 63 64 // This method contains all heap specific policy for invoking mark sweep. 65 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact 66 // the heap. It will do nothing further. If we need to bail out for policy 67 // reasons, scavenge before full gc, or any other specialized behavior, it 68 // needs to be added here. 69 // 70 // Note that this method should only be called from the vm_thread while 71 // at a safepoint! 72 // 73 // Note that the all_soft_refs_clear flag in the collector policy 74 // may be true because this method can be called without intervening 75 // activity. For example when the heap space is tight and full measure 76 // are being taken to free space. 77 78 void PSMarkSweep::invoke(bool maximum_heap_compaction) { 79 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 80 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); 81 assert(!Universe::heap()->is_gc_active(), "not reentrant"); 82 83 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 84 GCCause::Cause gc_cause = heap->gc_cause(); 85 PSAdaptiveSizePolicy* policy = heap->size_policy(); 86 IsGCActiveMark mark; 87 88 if (ScavengeBeforeFullGC) { 89 PSScavenge::invoke_no_policy(); 90 } 91 92 const bool clear_all_soft_refs = 93 heap->collector_policy()->should_clear_all_soft_refs(); 94 95 int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount; 96 IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); 97 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); 98 } 99 100 // This method contains no policy. You should probably 101 // be calling invoke() instead. 102 bool PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { 103 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); 104 assert(ref_processor() != NULL, "Sanity"); 105 106 if (GC_locker::check_active_before_gc()) { 107 return false; 108 } 109 110 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 111 GCCause::Cause gc_cause = heap->gc_cause(); 112 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 113 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); 114 115 // The scope of casr should end after code that can change 116 // CollectorPolicy::_should_clear_all_soft_refs. 117 ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); 118 119 PSYoungGen* young_gen = heap->young_gen(); 120 PSOldGen* old_gen = heap->old_gen(); 121 122 // Increment the invocation count 123 heap->increment_total_collections(true /* full */); 124 125 // Save information needed to minimize mangling 126 heap->record_gen_tops_before_GC(); 127 128 // We need to track unique mark sweep invocations as well. 129 _total_invocations++; 130 131 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); 132 133 heap->print_heap_before_gc(); 134 135 // Fill in TLABs 136 heap->accumulate_statistics_all_tlabs(); 137 heap->ensure_parsability(true); // retire TLABs 138 139 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { 140 HandleMark hm; // Discard invalid handles created during verification 141 Universe::verify(" VerifyBeforeGC:"); 142 } 143 144 // Verify object start arrays 145 if (VerifyObjectStartArray && 146 VerifyBeforeGC) { 147 old_gen->verify_object_start_array(); 148 } 149 150 heap->pre_full_gc_dump(); 151 152 // Filled in below to track the state of the young gen after the collection. 153 bool eden_empty; 154 bool survivors_empty; 155 bool young_gen_empty; 156 157 { 158 HandleMark hm; 159 160 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); 161 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); 162 TraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, gclog_or_tty); 163 TraceCollectorStats tcs(counters()); 164 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); 165 166 if (TraceGen1Time) accumulated_time()->start(); 167 168 // Let the size policy know we're starting 169 size_policy->major_collection_begin(); 170 171 CodeCache::gc_prologue(); 172 Threads::gc_prologue(); 173 BiasedLocking::preserve_marks(); 174 175 // Capture heap size before collection for printing. 176 size_t prev_used = heap->used(); 177 178 // Capture metadata size before collection for sizing. 179 size_t metadata_prev_used = MetaspaceAux::allocated_used_bytes(); 180 181 // For PrintGCDetails 182 size_t old_gen_prev_used = old_gen->used_in_bytes(); 183 size_t young_gen_prev_used = young_gen->used_in_bytes(); 184 185 allocate_stacks(); 186 187 COMPILER2_PRESENT(DerivedPointerTable::clear()); 188 189 ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/); 190 ref_processor()->setup_policy(clear_all_softrefs); 191 192 mark_sweep_phase1(clear_all_softrefs); 193 194 mark_sweep_phase2(); 195 196 // Don't add any more derived pointers during phase3 197 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); 198 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); 199 200 mark_sweep_phase3(); 201 202 mark_sweep_phase4(); 203 204 restore_marks(); 205 206 deallocate_stacks(); 207 208 if (ZapUnusedHeapArea) { 209 // Do a complete mangle (top to end) because the usage for 210 // scratch does not maintain a top pointer. 211 young_gen->to_space()->mangle_unused_area_complete(); 212 } 213 214 eden_empty = young_gen->eden_space()->is_empty(); 215 if (!eden_empty) { 216 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); 217 } 218 219 // Update heap occupancy information which is used as 220 // input to soft ref clearing policy at the next gc. 221 Universe::update_heap_info_at_gc(); 222 223 survivors_empty = young_gen->from_space()->is_empty() && 224 young_gen->to_space()->is_empty(); 225 young_gen_empty = eden_empty && survivors_empty; 226 227 BarrierSet* bs = heap->barrier_set(); 228 if (bs->is_a(BarrierSet::ModRef)) { 229 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; 230 MemRegion old_mr = heap->old_gen()->reserved(); 231 if (young_gen_empty) { 232 modBS->clear(MemRegion(old_mr.start(), old_mr.end())); 233 } else { 234 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end())); 235 } 236 } 237 238 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 239 ClassLoaderDataGraph::purge(); 240 MetaspaceAux::verify_metrics(); 241 242 BiasedLocking::restore_marks(); 243 Threads::gc_epilogue(); 244 CodeCache::gc_epilogue(); 245 JvmtiExport::gc_epilogue(); 246 247 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 248 249 ref_processor()->enqueue_discovered_references(NULL); 250 251 // Update time of last GC 252 reset_millis_since_last_gc(); 253 254 // Let the size policy know we're done 255 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); 256 257 if (UseAdaptiveSizePolicy) { 258 259 if (PrintAdaptiveSizePolicy) { 260 gclog_or_tty->print("AdaptiveSizeStart: "); 261 gclog_or_tty->stamp(); 262 gclog_or_tty->print_cr(" collection: %d ", 263 heap->total_collections()); 264 if (Verbose) { 265 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d", 266 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes()); 267 } 268 } 269 270 // Don't check if the size_policy is ready here. Let 271 // the size_policy check that internally. 272 if (UseAdaptiveGenerationSizePolicyAtMajorCollection && 273 ((gc_cause != GCCause::_java_lang_system_gc) || 274 UseAdaptiveSizePolicyWithSystemGC)) { 275 // Calculate optimal free space amounts 276 assert(young_gen->max_size() > 277 young_gen->from_space()->capacity_in_bytes() + 278 young_gen->to_space()->capacity_in_bytes(), 279 "Sizes of space in young gen are out-of-bounds"); 280 size_t max_eden_size = young_gen->max_size() - 281 young_gen->from_space()->capacity_in_bytes() - 282 young_gen->to_space()->capacity_in_bytes(); 283 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), 284 young_gen->eden_space()->used_in_bytes(), 285 old_gen->used_in_bytes(), 286 young_gen->eden_space()->capacity_in_bytes(), 287 old_gen->max_gen_size(), 288 max_eden_size, 289 true /* full gc*/, 290 gc_cause, 291 heap->collector_policy()); 292 293 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); 294 295 // Don't resize the young generation at an major collection. A 296 // desired young generation size may have been calculated but 297 // resizing the young generation complicates the code because the 298 // resizing of the old generation may have moved the boundary 299 // between the young generation and the old generation. Let the 300 // young generation resizing happen at the minor collections. 301 } 302 if (PrintAdaptiveSizePolicy) { 303 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", 304 heap->total_collections()); 305 } 306 } 307 308 if (UsePerfData) { 309 heap->gc_policy_counters()->update_counters(); 310 heap->gc_policy_counters()->update_old_capacity( 311 old_gen->capacity_in_bytes()); 312 heap->gc_policy_counters()->update_young_capacity( 313 young_gen->capacity_in_bytes()); 314 } 315 316 heap->resize_all_tlabs(); 317 318 // We collected the heap, recalculate the metaspace capacity 319 MetaspaceGC::compute_new_size(); 320 321 if (TraceGen1Time) accumulated_time()->stop(); 322 323 if (PrintGC) { 324 if (PrintGCDetails) { 325 // Don't print a GC timestamp here. This is after the GC so 326 // would be confusing. 327 young_gen->print_used_change(young_gen_prev_used); 328 old_gen->print_used_change(old_gen_prev_used); 329 } 330 heap->print_heap_change(prev_used); 331 if (PrintGCDetails) { 332 MetaspaceAux::print_metaspace_change(metadata_prev_used); 333 } 334 } 335 336 // Track memory usage and detect low memory 337 MemoryService::track_memory_usage(); 338 heap->update_counters(); 339 } 340 341 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { 342 HandleMark hm; // Discard invalid handles created during verification 343 Universe::verify(" VerifyAfterGC:"); 344 } 345 346 // Re-verify object start arrays 347 if (VerifyObjectStartArray && 348 VerifyAfterGC) { 349 old_gen->verify_object_start_array(); 350 } 351 352 if (ZapUnusedHeapArea) { 353 old_gen->object_space()->check_mangled_unused_area_complete(); 354 } 355 356 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); 357 358 heap->print_heap_after_gc(); 359 360 heap->post_full_gc_dump(); 361 362 #ifdef TRACESPINNING 363 ParallelTaskTerminator::print_termination_counts(); 364 #endif 365 366 return true; 367 } 368 369 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, 370 PSYoungGen* young_gen, 371 PSOldGen* old_gen) { 372 MutableSpace* const eden_space = young_gen->eden_space(); 373 assert(!eden_space->is_empty(), "eden must be non-empty"); 374 assert(young_gen->virtual_space()->alignment() == 375 old_gen->virtual_space()->alignment(), "alignments do not match"); 376 377 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { 378 return false; 379 } 380 381 // Both generations must be completely committed. 382 if (young_gen->virtual_space()->uncommitted_size() != 0) { 383 return false; 384 } 385 if (old_gen->virtual_space()->uncommitted_size() != 0) { 386 return false; 387 } 388 389 // Figure out how much to take from eden. Include the average amount promoted 390 // in the total; otherwise the next young gen GC will simply bail out to a 391 // full GC. 392 const size_t alignment = old_gen->virtual_space()->alignment(); 393 const size_t eden_used = eden_space->used_in_bytes(); 394 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); 395 const size_t absorb_size = align_size_up(eden_used + promoted, alignment); 396 const size_t eden_capacity = eden_space->capacity_in_bytes(); 397 398 if (absorb_size >= eden_capacity) { 399 return false; // Must leave some space in eden. 400 } 401 402 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; 403 if (new_young_size < young_gen->min_gen_size()) { 404 return false; // Respect young gen minimum size. 405 } 406 407 if (TraceAdaptiveGCBoundary && Verbose) { 408 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " 409 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " 410 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " 411 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", 412 absorb_size / K, 413 eden_capacity / K, (eden_capacity - absorb_size) / K, 414 young_gen->from_space()->used_in_bytes() / K, 415 young_gen->to_space()->used_in_bytes() / K, 416 young_gen->capacity_in_bytes() / K, new_young_size / K); 417 } 418 419 // Fill the unused part of the old gen. 420 MutableSpace* const old_space = old_gen->object_space(); 421 HeapWord* const unused_start = old_space->top(); 422 size_t const unused_words = pointer_delta(old_space->end(), unused_start); 423 424 if (unused_words > 0) { 425 if (unused_words < CollectedHeap::min_fill_size()) { 426 return false; // If the old gen cannot be filled, must give up. 427 } 428 CollectedHeap::fill_with_objects(unused_start, unused_words); 429 } 430 431 // Take the live data from eden and set both top and end in the old gen to 432 // eden top. (Need to set end because reset_after_change() mangles the region 433 // from end to virtual_space->high() in debug builds). 434 HeapWord* const new_top = eden_space->top(); 435 old_gen->virtual_space()->expand_into(young_gen->virtual_space(), 436 absorb_size); 437 young_gen->reset_after_change(); 438 old_space->set_top(new_top); 439 old_space->set_end(new_top); 440 old_gen->reset_after_change(); 441 442 // Update the object start array for the filler object and the data from eden. 443 ObjectStartArray* const start_array = old_gen->start_array(); 444 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { 445 start_array->allocate_block(p); 446 } 447 448 // Could update the promoted average here, but it is not typically updated at 449 // full GCs and the value to use is unclear. Something like 450 // 451 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. 452 453 size_policy->set_bytes_absorbed_from_eden(absorb_size); 454 return true; 455 } 456 457 void PSMarkSweep::allocate_stacks() { 458 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 459 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 460 461 PSYoungGen* young_gen = heap->young_gen(); 462 463 MutableSpace* to_space = young_gen->to_space(); 464 _preserved_marks = (PreservedMark*)to_space->top(); 465 _preserved_count = 0; 466 467 // We want to calculate the size in bytes first. 468 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); 469 // Now divide by the size of a PreservedMark 470 _preserved_count_max /= sizeof(PreservedMark); 471 } 472 473 474 void PSMarkSweep::deallocate_stacks() { 475 _preserved_mark_stack.clear(true); 476 _preserved_oop_stack.clear(true); 477 _marking_stack.clear(); 478 _objarray_stack.clear(true); 479 } 480 481 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { 482 // Recursively traverse all live objects and mark them 483 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); 484 trace(" 1"); 485 486 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 487 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 488 489 // Need to clear claim bits before the tracing starts. 490 ClassLoaderDataGraph::clear_claimed_marks(); 491 492 // General strong roots. 493 { 494 ParallelScavengeHeap::ParStrongRootsScope psrs; 495 Universe::oops_do(mark_and_push_closure()); 496 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles 497 CLDToOopClosure mark_and_push_from_cld(mark_and_push_closure()); 498 CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true); 499 Threads::oops_do(mark_and_push_closure(), &mark_and_push_from_cld, &each_active_code_blob); 500 ObjectSynchronizer::oops_do(mark_and_push_closure()); 501 FlatProfiler::oops_do(mark_and_push_closure()); 502 Management::oops_do(mark_and_push_closure()); 503 JvmtiExport::oops_do(mark_and_push_closure()); 504 SystemDictionary::always_strong_oops_do(mark_and_push_closure()); 505 ClassLoaderDataGraph::always_strong_oops_do(mark_and_push_closure(), follow_klass_closure(), true); 506 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. 507 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); 508 } 509 510 // Flush marking stack. 511 follow_stack(); 512 513 // Process reference objects found during marking 514 { 515 ref_processor()->setup_policy(clear_all_softrefs); 516 ref_processor()->process_discovered_references( 517 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL); 518 } 519 520 // This is the point where the entire marking should have completed. 521 assert(_marking_stack.is_empty(), "Marking should have completed"); 522 523 // Unload classes and purge the SystemDictionary. 524 bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); 525 526 // Unload nmethods. 527 CodeCache::do_unloading(is_alive_closure(), purged_class); 528 529 // Prune dead klasses from subklass/sibling/implementor lists. 530 Klass::clean_weak_klass_links(is_alive_closure()); 531 532 // Delete entries for dead interned strings. 533 StringTable::unlink(is_alive_closure()); 534 535 // Clean up unreferenced symbols in symbol table. 536 SymbolTable::unlink(); 537 } 538 539 540 void PSMarkSweep::mark_sweep_phase2() { 541 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); 542 trace("2"); 543 544 // Now all live objects are marked, compute the new object addresses. 545 546 // It is not required that we traverse spaces in the same order in 547 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops 548 // tracking expects us to do so. See comment under phase4. 549 550 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 551 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 552 553 PSOldGen* old_gen = heap->old_gen(); 554 555 // Begin compacting into the old gen 556 PSMarkSweepDecorator::set_destination_decorator_tenured(); 557 558 // This will also compact the young gen spaces. 559 old_gen->precompact(); 560 } 561 562 // This should be moved to the shared markSweep code! 563 class PSAlwaysTrueClosure: public BoolObjectClosure { 564 public: 565 bool do_object_b(oop p) { return true; } 566 }; 567 static PSAlwaysTrueClosure always_true; 568 569 void PSMarkSweep::mark_sweep_phase3() { 570 // Adjust the pointers to reflect the new locations 571 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); 572 trace("3"); 573 574 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 575 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 576 577 PSYoungGen* young_gen = heap->young_gen(); 578 PSOldGen* old_gen = heap->old_gen(); 579 580 // Need to clear claim bits before the tracing starts. 581 ClassLoaderDataGraph::clear_claimed_marks(); 582 583 // General strong roots. 584 Universe::oops_do(adjust_pointer_closure()); 585 JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles 586 CLDToOopClosure adjust_from_cld(adjust_pointer_closure()); 587 Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL); 588 ObjectSynchronizer::oops_do(adjust_pointer_closure()); 589 FlatProfiler::oops_do(adjust_pointer_closure()); 590 Management::oops_do(adjust_pointer_closure()); 591 JvmtiExport::oops_do(adjust_pointer_closure()); 592 // SO_AllClasses 593 SystemDictionary::oops_do(adjust_pointer_closure()); 594 ClassLoaderDataGraph::oops_do(adjust_pointer_closure(), adjust_klass_closure(), true); 595 596 // Now adjust pointers in remaining weak roots. (All of which should 597 // have been cleared if they pointed to non-surviving objects.) 598 // Global (weak) JNI handles 599 JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure()); 600 601 CodeCache::oops_do(adjust_pointer_closure()); 602 StringTable::oops_do(adjust_pointer_closure()); 603 ref_processor()->weak_oops_do(adjust_pointer_closure()); 604 PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure()); 605 606 adjust_marks(); 607 608 young_gen->adjust_pointers(); 609 old_gen->adjust_pointers(); 610 } 611 612 void PSMarkSweep::mark_sweep_phase4() { 613 EventMark m("4 compact heap"); 614 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); 615 trace("4"); 616 617 // All pointers are now adjusted, move objects accordingly 618 619 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 620 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 621 622 PSYoungGen* young_gen = heap->young_gen(); 623 PSOldGen* old_gen = heap->old_gen(); 624 625 old_gen->compact(); 626 young_gen->compact(); 627 } 628 629 jlong PSMarkSweep::millis_since_last_gc() { 630 // We need a monotonically non-deccreasing time in ms but 631 // os::javaTimeMillis() does not guarantee monotonicity. 632 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 633 jlong ret_val = now - _time_of_last_gc; 634 // XXX See note in genCollectedHeap::millis_since_last_gc(). 635 if (ret_val < 0) { 636 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);) 637 return 0; 638 } 639 return ret_val; 640 } 641 642 void PSMarkSweep::reset_millis_since_last_gc() { 643 // We need a monotonically non-deccreasing time in ms but 644 // os::javaTimeMillis() does not guarantee monotonicity. 645 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 646 }