1 /* 2 * Copyright (c) 2000, 2017, 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 "aot/aotLoader.hpp" 27 #include "classfile/symbolTable.hpp" 28 #include "classfile/stringTable.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "code/codeCache.hpp" 32 #include "code/icBuffer.hpp" 33 #include "gc/shared/collectedHeap.inline.hpp" 34 #include "gc/shared/collectorCounters.hpp" 35 #include "gc/shared/gcId.hpp" 36 #include "gc/shared/gcLocker.inline.hpp" 37 #include "gc/shared/gcTrace.hpp" 38 #include "gc/shared/gcTraceTime.inline.hpp" 39 #include "gc/shared/genCollectedHeap.hpp" 40 #include "gc/shared/genOopClosures.inline.hpp" 41 #include "gc/shared/generationSpec.hpp" 42 #include "gc/shared/space.hpp" 43 #include "gc/shared/strongRootsScope.hpp" 44 #include "gc/shared/vmGCOperations.hpp" 45 #include "gc/shared/weakProcessor.hpp" 46 #include "gc/shared/workgroup.hpp" 47 #include "memory/filemap.hpp" 48 #include "memory/resourceArea.hpp" 49 #include "oops/oop.inline.hpp" 50 #include "runtime/biasedLocking.hpp" 51 #include "runtime/handles.hpp" 52 #include "runtime/handles.inline.hpp" 53 #include "runtime/java.hpp" 54 #include "runtime/vmThread.hpp" 55 #include "services/management.hpp" 56 #include "services/memoryService.hpp" 57 #include "utilities/debug.hpp" 58 #include "utilities/formatBuffer.hpp" 59 #include "utilities/macros.hpp" 60 #include "utilities/stack.inline.hpp" 61 #include "utilities/vmError.hpp" 62 #if INCLUDE_ALL_GCS 63 #include "gc/cms/concurrentMarkSweepThread.hpp" 64 #include "gc/cms/vmCMSOperations.hpp" 65 #endif // INCLUDE_ALL_GCS 66 67 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) 68 69 // The set of potentially parallel tasks in root scanning. 70 enum GCH_strong_roots_tasks { 71 GCH_PS_Universe_oops_do, 72 GCH_PS_JNIHandles_oops_do, 73 GCH_PS_ObjectSynchronizer_oops_do, 74 GCH_PS_Management_oops_do, 75 GCH_PS_SystemDictionary_oops_do, 76 GCH_PS_ClassLoaderDataGraph_oops_do, 77 GCH_PS_jvmti_oops_do, 78 GCH_PS_CodeCache_oops_do, 79 GCH_PS_aot_oops_do, 80 GCH_PS_younger_gens, 81 // Leave this one last. 82 GCH_PS_NumElements 83 }; 84 85 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) : 86 CollectedHeap(), 87 _rem_set(NULL), 88 _gen_policy(policy), 89 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)), 90 _full_collections_completed(0) 91 { 92 assert(policy != NULL, "Sanity check"); 93 if (UseConcMarkSweepGC) { 94 _workers = new WorkGang("GC Thread", ParallelGCThreads, 95 /* are_GC_task_threads */true, 96 /* are_ConcurrentGC_threads */false); 97 _workers->initialize_workers(); 98 } else { 99 // Serial GC does not use workers. 100 _workers = NULL; 101 } 102 } 103 104 jint GenCollectedHeap::initialize() { 105 CollectedHeap::pre_initialize(); 106 107 // While there are no constraints in the GC code that HeapWordSize 108 // be any particular value, there are multiple other areas in the 109 // system which believe this to be true (e.g. oop->object_size in some 110 // cases incorrectly returns the size in wordSize units rather than 111 // HeapWordSize). 112 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); 113 114 // Allocate space for the heap. 115 116 char* heap_address; 117 ReservedSpace heap_rs; 118 119 size_t heap_alignment = collector_policy()->heap_alignment(); 120 121 heap_address = allocate(heap_alignment, &heap_rs); 122 123 if (!heap_rs.is_reserved()) { 124 vm_shutdown_during_initialization( 125 "Could not reserve enough space for object heap"); 126 return JNI_ENOMEM; 127 } 128 129 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size())); 130 131 _rem_set = collector_policy()->create_rem_set(reserved_region()); 132 set_barrier_set(rem_set()->bs()); 133 134 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false); 135 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, rem_set()); 136 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size()); 137 138 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false); 139 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, rem_set()); 140 clear_incremental_collection_failed(); 141 142 #if INCLUDE_ALL_GCS 143 // If we are running CMS, create the collector responsible 144 // for collecting the CMS generations. 145 if (collector_policy()->is_concurrent_mark_sweep_policy()) { 146 bool success = create_cms_collector(); 147 if (!success) return JNI_ENOMEM; 148 } 149 #endif // INCLUDE_ALL_GCS 150 151 return JNI_OK; 152 } 153 154 char* GenCollectedHeap::allocate(size_t alignment, 155 ReservedSpace* heap_rs){ 156 // Now figure out the total size. 157 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size(); 158 assert(alignment % pageSize == 0, "Must be"); 159 160 GenerationSpec* young_spec = gen_policy()->young_gen_spec(); 161 GenerationSpec* old_spec = gen_policy()->old_gen_spec(); 162 163 // Check for overflow. 164 size_t total_reserved = young_spec->max_size() + old_spec->max_size(); 165 if (total_reserved < young_spec->max_size()) { 166 vm_exit_during_initialization("The size of the object heap + VM data exceeds " 167 "the maximum representable size"); 168 } 169 assert(total_reserved % alignment == 0, 170 "Gen size; total_reserved=" SIZE_FORMAT ", alignment=" 171 SIZE_FORMAT, total_reserved, alignment); 172 173 *heap_rs = Universe::reserve_heap(total_reserved, alignment); 174 175 os::trace_page_sizes("Heap", 176 collector_policy()->min_heap_byte_size(), 177 total_reserved, 178 alignment, 179 heap_rs->base(), 180 heap_rs->size()); 181 182 return heap_rs->base(); 183 } 184 185 void GenCollectedHeap::post_initialize() { 186 ref_processing_init(); 187 assert((_young_gen->kind() == Generation::DefNew) || 188 (_young_gen->kind() == Generation::ParNew), 189 "Wrong youngest generation type"); 190 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; 191 192 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep || 193 _old_gen->kind() == Generation::MarkSweepCompact, 194 "Wrong generation kind"); 195 196 _gen_policy->initialize_size_policy(def_new_gen->eden()->capacity(), 197 _old_gen->capacity(), 198 def_new_gen->from()->capacity()); 199 _gen_policy->initialize_gc_policy_counters(); 200 } 201 202 void GenCollectedHeap::ref_processing_init() { 203 _young_gen->ref_processor_init(); 204 _old_gen->ref_processor_init(); 205 } 206 207 size_t GenCollectedHeap::capacity() const { 208 return _young_gen->capacity() + _old_gen->capacity(); 209 } 210 211 size_t GenCollectedHeap::used() const { 212 return _young_gen->used() + _old_gen->used(); 213 } 214 215 void GenCollectedHeap::save_used_regions() { 216 _old_gen->save_used_region(); 217 _young_gen->save_used_region(); 218 } 219 220 size_t GenCollectedHeap::max_capacity() const { 221 return _young_gen->max_capacity() + _old_gen->max_capacity(); 222 } 223 224 // Update the _full_collections_completed counter 225 // at the end of a stop-world full GC. 226 unsigned int GenCollectedHeap::update_full_collections_completed() { 227 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 228 assert(_full_collections_completed <= _total_full_collections, 229 "Can't complete more collections than were started"); 230 _full_collections_completed = _total_full_collections; 231 ml.notify_all(); 232 return _full_collections_completed; 233 } 234 235 // Update the _full_collections_completed counter, as appropriate, 236 // at the end of a concurrent GC cycle. Note the conditional update 237 // below to allow this method to be called by a concurrent collector 238 // without synchronizing in any manner with the VM thread (which 239 // may already have initiated a STW full collection "concurrently"). 240 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 241 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 242 assert((_full_collections_completed <= _total_full_collections) && 243 (count <= _total_full_collections), 244 "Can't complete more collections than were started"); 245 if (count > _full_collections_completed) { 246 _full_collections_completed = count; 247 ml.notify_all(); 248 } 249 return _full_collections_completed; 250 } 251 252 253 #ifndef PRODUCT 254 // Override of memory state checking method in CollectedHeap: 255 // Some collectors (CMS for example) can't have badHeapWordVal written 256 // in the first two words of an object. (For instance , in the case of 257 // CMS these words hold state used to synchronize between certain 258 // (concurrent) GC steps and direct allocating mutators.) 259 // The skip_header_HeapWords() method below, allows us to skip 260 // over the requisite number of HeapWord's. Note that (for 261 // generational collectors) this means that those many words are 262 // skipped in each object, irrespective of the generation in which 263 // that object lives. The resultant loss of precision seems to be 264 // harmless and the pain of avoiding that imprecision appears somewhat 265 // higher than we are prepared to pay for such rudimentary debugging 266 // support. 267 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, 268 size_t size) { 269 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 270 // We are asked to check a size in HeapWords, 271 // but the memory is mangled in juint words. 272 juint* start = (juint*) (addr + skip_header_HeapWords()); 273 juint* end = (juint*) (addr + size); 274 for (juint* slot = start; slot < end; slot += 1) { 275 assert(*slot == badHeapWordVal, 276 "Found non badHeapWordValue in pre-allocation check"); 277 } 278 } 279 } 280 #endif 281 282 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 283 bool is_tlab, 284 bool first_only) { 285 HeapWord* res = NULL; 286 287 if (_young_gen->should_allocate(size, is_tlab)) { 288 res = _young_gen->allocate(size, is_tlab); 289 if (res != NULL || first_only) { 290 return res; 291 } 292 } 293 294 if (_old_gen->should_allocate(size, is_tlab)) { 295 res = _old_gen->allocate(size, is_tlab); 296 } 297 298 return res; 299 } 300 301 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 302 bool* gc_overhead_limit_was_exceeded) { 303 return gen_policy()->mem_allocate_work(size, 304 false /* is_tlab */, 305 gc_overhead_limit_was_exceeded); 306 } 307 308 bool GenCollectedHeap::must_clear_all_soft_refs() { 309 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs || 310 _gc_cause == GCCause::_wb_full_gc; 311 } 312 313 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { 314 if (!UseConcMarkSweepGC) { 315 return false; 316 } 317 318 switch (cause) { 319 case GCCause::_gc_locker: return GCLockerInvokesConcurrent; 320 case GCCause::_java_lang_system_gc: 321 case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent; 322 default: return false; 323 } 324 } 325 326 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, 327 bool is_tlab, bool run_verification, bool clear_soft_refs, 328 bool restore_marks_for_biased_locking) { 329 FormatBuffer<> title("Collect gen: %s", gen->short_name()); 330 GCTraceTime(Trace, gc, phases) t1(title); 331 TraceCollectorStats tcs(gen->counters()); 332 TraceMemoryManagerStats tmms(gen->kind(),gc_cause()); 333 334 gen->stat_record()->invocations++; 335 gen->stat_record()->accumulated_time.start(); 336 337 // Must be done anew before each collection because 338 // a previous collection will do mangling and will 339 // change top of some spaces. 340 record_gen_tops_before_GC(); 341 342 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize); 343 344 if (run_verification && VerifyBeforeGC) { 345 HandleMark hm; // Discard invalid handles created during verification 346 Universe::verify("Before GC"); 347 } 348 COMPILER2_PRESENT(DerivedPointerTable::clear()); 349 350 if (restore_marks_for_biased_locking) { 351 // We perform this mark word preservation work lazily 352 // because it's only at this point that we know whether we 353 // absolutely have to do it; we want to avoid doing it for 354 // scavenge-only collections where it's unnecessary 355 BiasedLocking::preserve_marks(); 356 } 357 358 // Do collection work 359 { 360 // Note on ref discovery: For what appear to be historical reasons, 361 // GCH enables and disabled (by enqueing) refs discovery. 362 // In the future this should be moved into the generation's 363 // collect method so that ref discovery and enqueueing concerns 364 // are local to a generation. The collect method could return 365 // an appropriate indication in the case that notification on 366 // the ref lock was needed. This will make the treatment of 367 // weak refs more uniform (and indeed remove such concerns 368 // from GCH). XXX 369 370 HandleMark hm; // Discard invalid handles created during gc 371 save_marks(); // save marks for all gens 372 // We want to discover references, but not process them yet. 373 // This mode is disabled in process_discovered_references if the 374 // generation does some collection work, or in 375 // enqueue_discovered_references if the generation returns 376 // without doing any work. 377 ReferenceProcessor* rp = gen->ref_processor(); 378 // If the discovery of ("weak") refs in this generation is 379 // atomic wrt other collectors in this configuration, we 380 // are guaranteed to have empty discovered ref lists. 381 if (rp->discovery_is_atomic()) { 382 rp->enable_discovery(); 383 rp->setup_policy(clear_soft_refs); 384 } else { 385 // collect() below will enable discovery as appropriate 386 } 387 gen->collect(full, clear_soft_refs, size, is_tlab); 388 if (!rp->enqueuing_is_done()) { 389 ReferenceProcessorPhaseTimes pt(NULL, rp->num_q()); 390 rp->enqueue_discovered_references(NULL, &pt); 391 pt.print_enqueue_phase(); 392 } else { 393 rp->set_enqueuing_is_done(false); 394 } 395 rp->verify_no_references_recorded(); 396 } 397 398 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 399 400 gen->stat_record()->accumulated_time.stop(); 401 402 update_gc_stats(gen, full); 403 404 if (run_verification && VerifyAfterGC) { 405 HandleMark hm; // Discard invalid handles created during verification 406 Universe::verify("After GC"); 407 } 408 } 409 410 void GenCollectedHeap::do_collection(bool full, 411 bool clear_all_soft_refs, 412 size_t size, 413 bool is_tlab, 414 GenerationType max_generation) { 415 ResourceMark rm; 416 DEBUG_ONLY(Thread* my_thread = Thread::current();) 417 418 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 419 assert(my_thread->is_VM_thread() || 420 my_thread->is_ConcurrentGC_thread(), 421 "incorrect thread type capability"); 422 assert(Heap_lock->is_locked(), 423 "the requesting thread should have the Heap_lock"); 424 guarantee(!is_gc_active(), "collection is not reentrant"); 425 426 if (GCLocker::check_active_before_gc()) { 427 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 428 } 429 430 GCIdMarkAndRestore gc_id_mark; 431 432 const bool do_clear_all_soft_refs = clear_all_soft_refs || 433 collector_policy()->should_clear_all_soft_refs(); 434 435 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); 436 437 const size_t metadata_prev_used = MetaspaceAux::used_bytes(); 438 439 print_heap_before_gc(); 440 441 { 442 FlagSetting fl(_is_gc_active, true); 443 444 bool complete = full && (max_generation == OldGen); 445 bool old_collects_young = complete && !ScavengeBeforeFullGC; 446 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab); 447 448 FormatBuffer<> gc_string("%s", "Pause "); 449 if (do_young_collection) { 450 gc_string.append("Young"); 451 } else { 452 gc_string.append("Full"); 453 } 454 455 GCTraceCPUTime tcpu; 456 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true); 457 458 gc_prologue(complete); 459 increment_total_collections(complete); 460 461 size_t young_prev_used = _young_gen->used(); 462 size_t old_prev_used = _old_gen->used(); 463 464 bool run_verification = total_collections() >= VerifyGCStartAt; 465 466 bool prepared_for_verification = false; 467 bool collected_old = false; 468 469 if (do_young_collection) { 470 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { 471 prepare_for_verify(); 472 prepared_for_verification = true; 473 } 474 475 collect_generation(_young_gen, 476 full, 477 size, 478 is_tlab, 479 run_verification && VerifyGCLevel <= 0, 480 do_clear_all_soft_refs, 481 false); 482 483 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && 484 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { 485 // Allocation request was met by young GC. 486 size = 0; 487 } 488 } 489 490 bool must_restore_marks_for_biased_locking = false; 491 492 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) { 493 if (!complete) { 494 // The full_collections increment was missed above. 495 increment_total_full_collections(); 496 } 497 498 if (!prepared_for_verification && run_verification && 499 VerifyGCLevel <= 1 && VerifyBeforeGC) { 500 prepare_for_verify(); 501 } 502 503 if (do_young_collection) { 504 // We did a young GC. Need a new GC id for the old GC. 505 GCIdMarkAndRestore gc_id_mark; 506 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true); 507 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true); 508 } else { 509 // No young GC done. Use the same GC id as was set up earlier in this method. 510 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true); 511 } 512 513 must_restore_marks_for_biased_locking = true; 514 collected_old = true; 515 } 516 517 // Update "complete" boolean wrt what actually transpired -- 518 // for instance, a promotion failure could have led to 519 // a whole heap collection. 520 complete = complete || collected_old; 521 522 print_heap_change(young_prev_used, old_prev_used); 523 MetaspaceAux::print_metaspace_change(metadata_prev_used); 524 525 // Adjust generation sizes. 526 if (collected_old) { 527 _old_gen->compute_new_size(); 528 } 529 _young_gen->compute_new_size(); 530 531 if (complete) { 532 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 533 ClassLoaderDataGraph::purge(); 534 MetaspaceAux::verify_metrics(); 535 // Resize the metaspace capacity after full collections 536 MetaspaceGC::compute_new_size(); 537 update_full_collections_completed(); 538 } 539 540 // Track memory usage and detect low memory after GC finishes 541 MemoryService::track_memory_usage(); 542 543 gc_epilogue(complete); 544 545 if (must_restore_marks_for_biased_locking) { 546 BiasedLocking::restore_marks(); 547 } 548 } 549 550 print_heap_after_gc(); 551 552 #ifdef TRACESPINNING 553 ParallelTaskTerminator::print_termination_counts(); 554 #endif 555 } 556 557 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 558 return gen_policy()->satisfy_failed_allocation(size, is_tlab); 559 } 560 561 #ifdef ASSERT 562 class AssertNonScavengableClosure: public OopClosure { 563 public: 564 virtual void do_oop(oop* p) { 565 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), 566 "Referent should not be scavengable."); } 567 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 568 }; 569 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 570 #endif 571 572 void GenCollectedHeap::process_roots(StrongRootsScope* scope, 573 ScanningOption so, 574 OopClosure* strong_roots, 575 OopClosure* weak_roots, 576 CLDClosure* strong_cld_closure, 577 CLDClosure* weak_cld_closure, 578 CodeBlobToOopClosure* code_roots) { 579 // General roots. 580 assert(Threads::thread_claim_parity() != 0, "must have called prologue code"); 581 assert(code_roots != NULL, "code root closure should always be set"); 582 // _n_termination for _process_strong_tasks should be set up stream 583 // in a method not running in a GC worker. Otherwise the GC worker 584 // could be trying to change the termination condition while the task 585 // is executing in another GC worker. 586 587 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) { 588 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); 589 } 590 591 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway 592 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; 593 594 bool is_par = scope->n_threads() > 1; 595 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p); 596 597 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) { 598 Universe::oops_do(strong_roots); 599 } 600 // Global (strong) JNI handles 601 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) { 602 JNIHandles::oops_do(strong_roots); 603 } 604 605 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) { 606 ObjectSynchronizer::oops_do(strong_roots); 607 } 608 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) { 609 Management::oops_do(strong_roots); 610 } 611 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) { 612 JvmtiExport::oops_do(strong_roots); 613 } 614 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) { 615 AOTLoader::oops_do(strong_roots); 616 } 617 618 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) { 619 SystemDictionary::roots_oops_do(strong_roots, weak_roots); 620 } 621 622 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) { 623 if (so & SO_ScavengeCodeCache) { 624 assert(code_roots != NULL, "must supply closure for code cache"); 625 626 // We only visit parts of the CodeCache when scavenging. 627 CodeCache::scavenge_root_nmethods_do(code_roots); 628 } 629 if (so & SO_AllCodeCache) { 630 assert(code_roots != NULL, "must supply closure for code cache"); 631 632 // CMSCollector uses this to do intermediate-strength collections. 633 // We scan the entire code cache, since CodeCache::do_unloading is not called. 634 CodeCache::blobs_do(code_roots); 635 } 636 // Verify that the code cache contents are not subject to 637 // movement by a scavenging collection. 638 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); 639 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 640 } 641 } 642 643 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope, 644 OopClosure* root_closure) { 645 assert(root_closure != NULL, "Must be set"); 646 // All threads execute the following. A specific chunk of buckets 647 // from the StringTable are the individual tasks. 648 if (scope->n_threads() > 1) { 649 StringTable::possibly_parallel_oops_do(root_closure); 650 } else { 651 StringTable::oops_do(root_closure); 652 } 653 } 654 655 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope, 656 OopsInGenClosure* root_closure, 657 OopsInGenClosure* old_gen_closure, 658 CLDClosure* cld_closure) { 659 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations); 660 661 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure, 662 cld_closure, cld_closure, &mark_code_closure); 663 process_string_table_roots(scope, root_closure); 664 665 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 666 root_closure->reset_generation(); 667 } 668 669 // When collection is parallel, all threads get to cooperate to do 670 // old generation scanning. 671 old_gen_closure->set_generation(_old_gen); 672 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads()); 673 old_gen_closure->reset_generation(); 674 675 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 676 } 677 678 void GenCollectedHeap::cms_process_roots(StrongRootsScope* scope, 679 bool young_gen_as_roots, 680 ScanningOption so, 681 bool only_strong_roots, 682 OopsInGenClosure* root_closure, 683 CLDClosure* cld_closure) { 684 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations); 685 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 686 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 687 688 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 689 if (!only_strong_roots) { 690 process_string_table_roots(scope, root_closure); 691 } 692 693 if (young_gen_as_roots && 694 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 695 root_closure->set_generation(_young_gen); 696 _young_gen->oop_iterate(root_closure); 697 root_closure->reset_generation(); 698 } 699 700 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 701 } 702 703 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope, 704 bool is_adjust_phase, 705 ScanningOption so, 706 bool only_strong_roots, 707 OopsInGenClosure* root_closure, 708 CLDClosure* cld_closure) { 709 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase); 710 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 711 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 712 713 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 714 if (is_adjust_phase) { 715 // We never treat the string table as roots during marking 716 // for the full gc, so we only need to process it during 717 // the adjust phase. 718 process_string_table_roots(scope, root_closure); 719 } 720 721 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 722 } 723 724 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { 725 WeakProcessor::oops_do(root_closure); 726 _young_gen->ref_processor()->weak_oops_do(root_closure); 727 _old_gen->ref_processor()->weak_oops_do(root_closure); 728 } 729 730 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 731 void GenCollectedHeap:: \ 732 oop_since_save_marks_iterate(GenerationType gen, \ 733 OopClosureType* cur, \ 734 OopClosureType* older) { \ 735 if (gen == YoungGen) { \ 736 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 737 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \ 738 } else { \ 739 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 740 } \ 741 } 742 743 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) 744 745 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN 746 747 bool GenCollectedHeap::no_allocs_since_save_marks() { 748 return _young_gen->no_allocs_since_save_marks() && 749 _old_gen->no_allocs_since_save_marks(); 750 } 751 752 bool GenCollectedHeap::supports_inline_contig_alloc() const { 753 return _young_gen->supports_inline_contig_alloc(); 754 } 755 756 HeapWord* volatile* GenCollectedHeap::top_addr() const { 757 return _young_gen->top_addr(); 758 } 759 760 HeapWord** GenCollectedHeap::end_addr() const { 761 return _young_gen->end_addr(); 762 } 763 764 // public collection interfaces 765 766 void GenCollectedHeap::collect(GCCause::Cause cause) { 767 if (should_do_concurrent_full_gc(cause)) { 768 #if INCLUDE_ALL_GCS 769 // Mostly concurrent full collection. 770 collect_mostly_concurrent(cause); 771 #else // INCLUDE_ALL_GCS 772 ShouldNotReachHere(); 773 #endif // INCLUDE_ALL_GCS 774 } else if (cause == GCCause::_wb_young_gc) { 775 // Young collection for the WhiteBox API. 776 collect(cause, YoungGen); 777 } else { 778 #ifdef ASSERT 779 if (cause == GCCause::_scavenge_alot) { 780 // Young collection only. 781 collect(cause, YoungGen); 782 } else { 783 // Stop-the-world full collection. 784 collect(cause, OldGen); 785 } 786 #else 787 // Stop-the-world full collection. 788 collect(cause, OldGen); 789 #endif 790 } 791 } 792 793 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) { 794 // The caller doesn't have the Heap_lock 795 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 796 MutexLocker ml(Heap_lock); 797 collect_locked(cause, max_generation); 798 } 799 800 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 801 // The caller has the Heap_lock 802 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 803 collect_locked(cause, OldGen); 804 } 805 806 // this is the private collection interface 807 // The Heap_lock is expected to be held on entry. 808 809 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) { 810 // Read the GC count while holding the Heap_lock 811 unsigned int gc_count_before = total_collections(); 812 unsigned int full_gc_count_before = total_full_collections(); 813 { 814 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 815 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 816 cause, max_generation); 817 VMThread::execute(&op); 818 } 819 } 820 821 #if INCLUDE_ALL_GCS 822 bool GenCollectedHeap::create_cms_collector() { 823 824 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep, 825 "Unexpected generation kinds"); 826 // Skip two header words in the block content verification 827 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) 828 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type"); 829 CMSCollector* collector = 830 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen, 831 _rem_set, 832 _gen_policy->as_concurrent_mark_sweep_policy()); 833 834 if (collector == NULL || !collector->completed_initialization()) { 835 if (collector) { 836 delete collector; // Be nice in embedded situation 837 } 838 vm_shutdown_during_initialization("Could not create CMS collector"); 839 return false; 840 } 841 return true; // success 842 } 843 844 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { 845 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 846 847 MutexLocker ml(Heap_lock); 848 // Read the GC counts while holding the Heap_lock 849 unsigned int full_gc_count_before = total_full_collections(); 850 unsigned int gc_count_before = total_collections(); 851 { 852 MutexUnlocker mu(Heap_lock); 853 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 854 VMThread::execute(&op); 855 } 856 } 857 #endif // INCLUDE_ALL_GCS 858 859 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { 860 do_full_collection(clear_all_soft_refs, OldGen); 861 } 862 863 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 864 GenerationType last_generation) { 865 GenerationType local_last_generation; 866 if (!incremental_collection_will_fail(false /* don't consult_young */) && 867 gc_cause() == GCCause::_gc_locker) { 868 local_last_generation = YoungGen; 869 } else { 870 local_last_generation = last_generation; 871 } 872 873 do_collection(true, // full 874 clear_all_soft_refs, // clear_all_soft_refs 875 0, // size 876 false, // is_tlab 877 local_last_generation); // last_generation 878 // Hack XXX FIX ME !!! 879 // A scavenge may not have been attempted, or may have 880 // been attempted and failed, because the old gen was too full 881 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker && 882 incremental_collection_will_fail(false /* don't consult_young */)) { 883 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed"); 884 // This time allow the old gen to be collected as well 885 do_collection(true, // full 886 clear_all_soft_refs, // clear_all_soft_refs 887 0, // size 888 false, // is_tlab 889 OldGen); // last_generation 890 } 891 } 892 893 bool GenCollectedHeap::is_in_young(oop p) { 894 bool result = ((HeapWord*)p) < _old_gen->reserved().start(); 895 assert(result == _young_gen->is_in_reserved(p), 896 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)); 897 return result; 898 } 899 900 // Returns "TRUE" iff "p" points into the committed areas of the heap. 901 bool GenCollectedHeap::is_in(const void* p) const { 902 return _young_gen->is_in(p) || _old_gen->is_in(p); 903 } 904 905 #ifdef ASSERT 906 // Don't implement this by using is_in_young(). This method is used 907 // in some cases to check that is_in_young() is correct. 908 bool GenCollectedHeap::is_in_partial_collection(const void* p) { 909 assert(is_in_reserved(p) || p == NULL, 910 "Does not work if address is non-null and outside of the heap"); 911 return p < _young_gen->reserved().end() && p != NULL; 912 } 913 #endif 914 915 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) { 916 NoHeaderExtendedOopClosure no_header_cl(cl); 917 oop_iterate(&no_header_cl); 918 } 919 920 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) { 921 _young_gen->oop_iterate(cl); 922 _old_gen->oop_iterate(cl); 923 } 924 925 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 926 _young_gen->object_iterate(cl); 927 _old_gen->object_iterate(cl); 928 } 929 930 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { 931 _young_gen->safe_object_iterate(cl); 932 _old_gen->safe_object_iterate(cl); 933 } 934 935 Space* GenCollectedHeap::space_containing(const void* addr) const { 936 Space* res = _young_gen->space_containing(addr); 937 if (res != NULL) { 938 return res; 939 } 940 res = _old_gen->space_containing(addr); 941 assert(res != NULL, "Could not find containing space"); 942 return res; 943 } 944 945 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 946 assert(is_in_reserved(addr), "block_start of address outside of heap"); 947 if (_young_gen->is_in_reserved(addr)) { 948 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 949 return _young_gen->block_start(addr); 950 } 951 952 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 953 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 954 return _old_gen->block_start(addr); 955 } 956 957 size_t GenCollectedHeap::block_size(const HeapWord* addr) const { 958 assert(is_in_reserved(addr), "block_size of address outside of heap"); 959 if (_young_gen->is_in_reserved(addr)) { 960 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 961 return _young_gen->block_size(addr); 962 } 963 964 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 965 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 966 return _old_gen->block_size(addr); 967 } 968 969 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 970 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 971 assert(block_start(addr) == addr, "addr must be a block start"); 972 if (_young_gen->is_in_reserved(addr)) { 973 return _young_gen->block_is_obj(addr); 974 } 975 976 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 977 return _old_gen->block_is_obj(addr); 978 } 979 980 bool GenCollectedHeap::supports_tlab_allocation() const { 981 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 982 return _young_gen->supports_tlab_allocation(); 983 } 984 985 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 986 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 987 if (_young_gen->supports_tlab_allocation()) { 988 return _young_gen->tlab_capacity(); 989 } 990 return 0; 991 } 992 993 size_t GenCollectedHeap::tlab_used(Thread* thr) const { 994 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 995 if (_young_gen->supports_tlab_allocation()) { 996 return _young_gen->tlab_used(); 997 } 998 return 0; 999 } 1000 1001 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1002 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1003 if (_young_gen->supports_tlab_allocation()) { 1004 return _young_gen->unsafe_max_tlab_alloc(); 1005 } 1006 return 0; 1007 } 1008 1009 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { 1010 bool gc_overhead_limit_was_exceeded; 1011 return gen_policy()->mem_allocate_work(size /* size */, 1012 true /* is_tlab */, 1013 &gc_overhead_limit_was_exceeded); 1014 } 1015 1016 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1017 // from the list headed by "*prev_ptr". 1018 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1019 bool first = true; 1020 size_t min_size = 0; // "first" makes this conceptually infinite. 1021 ScratchBlock **smallest_ptr, *smallest; 1022 ScratchBlock *cur = *prev_ptr; 1023 while (cur) { 1024 assert(*prev_ptr == cur, "just checking"); 1025 if (first || cur->num_words < min_size) { 1026 smallest_ptr = prev_ptr; 1027 smallest = cur; 1028 min_size = smallest->num_words; 1029 first = false; 1030 } 1031 prev_ptr = &cur->next; 1032 cur = cur->next; 1033 } 1034 smallest = *smallest_ptr; 1035 *smallest_ptr = smallest->next; 1036 return smallest; 1037 } 1038 1039 // Sort the scratch block list headed by res into decreasing size order, 1040 // and set "res" to the result. 1041 static void sort_scratch_list(ScratchBlock*& list) { 1042 ScratchBlock* sorted = NULL; 1043 ScratchBlock* unsorted = list; 1044 while (unsorted) { 1045 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1046 smallest->next = sorted; 1047 sorted = smallest; 1048 } 1049 list = sorted; 1050 } 1051 1052 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1053 size_t max_alloc_words) { 1054 ScratchBlock* res = NULL; 1055 _young_gen->contribute_scratch(res, requestor, max_alloc_words); 1056 _old_gen->contribute_scratch(res, requestor, max_alloc_words); 1057 sort_scratch_list(res); 1058 return res; 1059 } 1060 1061 void GenCollectedHeap::release_scratch() { 1062 _young_gen->reset_scratch(); 1063 _old_gen->reset_scratch(); 1064 } 1065 1066 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1067 void do_generation(Generation* gen) { 1068 gen->prepare_for_verify(); 1069 } 1070 }; 1071 1072 void GenCollectedHeap::prepare_for_verify() { 1073 ensure_parsability(false); // no need to retire TLABs 1074 GenPrepareForVerifyClosure blk; 1075 generation_iterate(&blk, false); 1076 } 1077 1078 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1079 bool old_to_young) { 1080 if (old_to_young) { 1081 cl->do_generation(_old_gen); 1082 cl->do_generation(_young_gen); 1083 } else { 1084 cl->do_generation(_young_gen); 1085 cl->do_generation(_old_gen); 1086 } 1087 } 1088 1089 bool GenCollectedHeap::is_maximal_no_gc() const { 1090 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); 1091 } 1092 1093 void GenCollectedHeap::save_marks() { 1094 _young_gen->save_marks(); 1095 _old_gen->save_marks(); 1096 } 1097 1098 GenCollectedHeap* GenCollectedHeap::heap() { 1099 CollectedHeap* heap = Universe::heap(); 1100 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1101 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap"); 1102 return (GenCollectedHeap*)heap; 1103 } 1104 1105 void GenCollectedHeap::prepare_for_compaction() { 1106 // Start by compacting into same gen. 1107 CompactPoint cp(_old_gen); 1108 _old_gen->prepare_for_compaction(&cp); 1109 _young_gen->prepare_for_compaction(&cp); 1110 } 1111 1112 void GenCollectedHeap::verify(VerifyOption option /* ignored */) { 1113 log_debug(gc, verify)("%s", _old_gen->name()); 1114 _old_gen->verify(); 1115 1116 log_debug(gc, verify)("%s", _old_gen->name()); 1117 _young_gen->verify(); 1118 1119 log_debug(gc, verify)("RemSet"); 1120 rem_set()->verify(); 1121 } 1122 1123 void GenCollectedHeap::print_on(outputStream* st) const { 1124 _young_gen->print_on(st); 1125 _old_gen->print_on(st); 1126 MetaspaceAux::print_on(st); 1127 } 1128 1129 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1130 if (workers() != NULL) { 1131 workers()->threads_do(tc); 1132 } 1133 #if INCLUDE_ALL_GCS 1134 if (UseConcMarkSweepGC) { 1135 ConcurrentMarkSweepThread::threads_do(tc); 1136 } 1137 #endif // INCLUDE_ALL_GCS 1138 } 1139 1140 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1141 #if INCLUDE_ALL_GCS 1142 if (UseConcMarkSweepGC) { 1143 workers()->print_worker_threads_on(st); 1144 ConcurrentMarkSweepThread::print_all_on(st); 1145 } 1146 #endif // INCLUDE_ALL_GCS 1147 } 1148 1149 void GenCollectedHeap::print_on_error(outputStream* st) const { 1150 this->CollectedHeap::print_on_error(st); 1151 1152 #if INCLUDE_ALL_GCS 1153 if (UseConcMarkSweepGC) { 1154 st->cr(); 1155 CMSCollector::print_on_error(st); 1156 } 1157 #endif // INCLUDE_ALL_GCS 1158 } 1159 1160 void GenCollectedHeap::print_tracing_info() const { 1161 if (log_is_enabled(Debug, gc, heap, exit)) { 1162 LogStreamHandle(Debug, gc, heap, exit) lsh; 1163 _young_gen->print_summary_info_on(&lsh); 1164 _old_gen->print_summary_info_on(&lsh); 1165 } 1166 } 1167 1168 void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const { 1169 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)", 1170 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K); 1171 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)", 1172 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K); 1173 } 1174 1175 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1176 private: 1177 bool _full; 1178 public: 1179 void do_generation(Generation* gen) { 1180 gen->gc_prologue(_full); 1181 } 1182 GenGCPrologueClosure(bool full) : _full(full) {}; 1183 }; 1184 1185 void GenCollectedHeap::gc_prologue(bool full) { 1186 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1187 1188 always_do_update_barrier = false; 1189 // Fill TLAB's and such 1190 CollectedHeap::accumulate_statistics_all_tlabs(); 1191 ensure_parsability(true); // retire TLABs 1192 1193 // Walk generations 1194 GenGCPrologueClosure blk(full); 1195 generation_iterate(&blk, false); // not old-to-young. 1196 }; 1197 1198 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1199 private: 1200 bool _full; 1201 public: 1202 void do_generation(Generation* gen) { 1203 gen->gc_epilogue(_full); 1204 } 1205 GenGCEpilogueClosure(bool full) : _full(full) {}; 1206 }; 1207 1208 void GenCollectedHeap::gc_epilogue(bool full) { 1209 #if defined(COMPILER2) || INCLUDE_JVMCI 1210 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1211 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1212 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1213 #endif /* COMPILER2 || INCLUDE_JVMCI */ 1214 1215 resize_all_tlabs(); 1216 1217 GenGCEpilogueClosure blk(full); 1218 generation_iterate(&blk, false); // not old-to-young. 1219 1220 if (!CleanChunkPoolAsync) { 1221 Chunk::clean_chunk_pool(); 1222 } 1223 1224 MetaspaceCounters::update_performance_counters(); 1225 CompressedClassSpaceCounters::update_performance_counters(); 1226 1227 always_do_update_barrier = UseConcMarkSweepGC; 1228 }; 1229 1230 #ifndef PRODUCT 1231 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1232 private: 1233 public: 1234 void do_generation(Generation* gen) { 1235 gen->record_spaces_top(); 1236 } 1237 }; 1238 1239 void GenCollectedHeap::record_gen_tops_before_GC() { 1240 if (ZapUnusedHeapArea) { 1241 GenGCSaveTopsBeforeGCClosure blk; 1242 generation_iterate(&blk, false); // not old-to-young. 1243 } 1244 } 1245 #endif // not PRODUCT 1246 1247 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1248 public: 1249 void do_generation(Generation* gen) { 1250 gen->ensure_parsability(); 1251 } 1252 }; 1253 1254 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1255 CollectedHeap::ensure_parsability(retire_tlabs); 1256 GenEnsureParsabilityClosure ep_cl; 1257 generation_iterate(&ep_cl, false); 1258 } 1259 1260 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, 1261 oop obj, 1262 size_t obj_size) { 1263 guarantee(old_gen == _old_gen, "We only get here with an old generation"); 1264 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1265 HeapWord* result = NULL; 1266 1267 result = old_gen->expand_and_allocate(obj_size, false); 1268 1269 if (result != NULL) { 1270 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 1271 } 1272 return oop(result); 1273 } 1274 1275 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1276 jlong _time; // in ms 1277 jlong _now; // in ms 1278 1279 public: 1280 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1281 1282 jlong time() { return _time; } 1283 1284 void do_generation(Generation* gen) { 1285 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1286 } 1287 }; 1288 1289 jlong GenCollectedHeap::millis_since_last_gc() { 1290 // javaTimeNanos() is guaranteed to be monotonically non-decreasing 1291 // provided the underlying platform provides such a time source 1292 // (and it is bug free). So we still have to guard against getting 1293 // back a time later than 'now'. 1294 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 1295 GenTimeOfLastGCClosure tolgc_cl(now); 1296 // iterate over generations getting the oldest 1297 // time that a generation was collected 1298 generation_iterate(&tolgc_cl, false); 1299 1300 jlong retVal = now - tolgc_cl.time(); 1301 if (retVal < 0) { 1302 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT 1303 ". returning zero instead.", retVal); 1304 return 0; 1305 } 1306 return retVal; 1307 } 1308 1309 void GenCollectedHeap::stop() { 1310 #if INCLUDE_ALL_GCS 1311 if (UseConcMarkSweepGC) { 1312 ConcurrentMarkSweepThread::cmst()->stop(); 1313 } 1314 #endif 1315 }