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/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/codeCache.hpp" 31 #include "code/icBuffer.hpp" 32 #include "gc/shared/collectedHeap.inline.hpp" 33 #include "gc/shared/collectorCounters.hpp" 34 #include "gc/shared/gcId.hpp" 35 #include "gc/shared/gcLocker.inline.hpp" 36 #include "gc/shared/gcTrace.hpp" 37 #include "gc/shared/gcTraceTime.inline.hpp" 38 #include "gc/shared/genCollectedHeap.hpp" 39 #include "gc/shared/genOopClosures.inline.hpp" 40 #include "gc/shared/generationSpec.hpp" 41 #include "gc/shared/space.hpp" 42 #include "gc/shared/strongRootsScope.hpp" 43 #include "gc/shared/vmGCOperations.hpp" 44 #include "gc/shared/workgroup.hpp" 45 #include "memory/filemap.hpp" 46 #include "memory/resourceArea.hpp" 47 #include "oops/oop.inline.hpp" 48 #include "runtime/biasedLocking.hpp" 49 #include "runtime/fprofiler.hpp" 50 #include "runtime/handles.hpp" 51 #include "runtime/handles.inline.hpp" 52 #include "runtime/java.hpp" 53 #include "runtime/vmThread.hpp" 54 #include "services/management.hpp" 55 #include "services/memoryService.hpp" 56 #include "utilities/debug.hpp" 57 #include "utilities/formatBuffer.hpp" 58 #include "utilities/macros.hpp" 59 #include "utilities/stack.inline.hpp" 60 #include "utilities/vmError.hpp" 61 #if INCLUDE_ALL_GCS 62 #include "gc/cms/concurrentMarkSweepThread.hpp" 63 #include "gc/cms/vmCMSOperations.hpp" 64 #endif // INCLUDE_ALL_GCS 65 66 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) 67 68 // The set of potentially parallel tasks in root scanning. 69 enum GCH_strong_roots_tasks { 70 GCH_PS_Universe_oops_do, 71 GCH_PS_JNIHandles_oops_do, 72 GCH_PS_ObjectSynchronizer_oops_do, 73 GCH_PS_FlatProfiler_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 rp->enqueue_discovered_references(); 390 } else { 391 rp->set_enqueuing_is_done(false); 392 } 393 rp->verify_no_references_recorded(); 394 } 395 396 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 397 398 gen->stat_record()->accumulated_time.stop(); 399 400 update_gc_stats(gen, full); 401 402 if (run_verification && VerifyAfterGC) { 403 HandleMark hm; // Discard invalid handles created during verification 404 Universe::verify("After GC"); 405 } 406 } 407 408 void GenCollectedHeap::do_collection(bool full, 409 bool clear_all_soft_refs, 410 size_t size, 411 bool is_tlab, 412 GenerationType max_generation) { 413 ResourceMark rm; 414 DEBUG_ONLY(Thread* my_thread = Thread::current();) 415 416 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 417 assert(my_thread->is_VM_thread() || 418 my_thread->is_ConcurrentGC_thread(), 419 "incorrect thread type capability"); 420 assert(Heap_lock->is_locked(), 421 "the requesting thread should have the Heap_lock"); 422 guarantee(!is_gc_active(), "collection is not reentrant"); 423 424 if (GCLocker::check_active_before_gc()) { 425 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 426 } 427 428 GCIdMarkAndRestore gc_id_mark; 429 430 const bool do_clear_all_soft_refs = clear_all_soft_refs || 431 collector_policy()->should_clear_all_soft_refs(); 432 433 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); 434 435 const size_t metadata_prev_used = MetaspaceAux::used_bytes(); 436 437 print_heap_before_gc(); 438 439 { 440 FlagSetting fl(_is_gc_active, true); 441 442 bool complete = full && (max_generation == OldGen); 443 bool old_collects_young = complete && !ScavengeBeforeFullGC; 444 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab); 445 446 FormatBuffer<> gc_string("%s", "Pause "); 447 if (do_young_collection) { 448 gc_string.append("Young"); 449 } else { 450 gc_string.append("Full"); 451 } 452 453 GCTraceCPUTime tcpu; 454 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true); 455 456 gc_prologue(complete); 457 increment_total_collections(complete); 458 459 size_t young_prev_used = _young_gen->used(); 460 size_t old_prev_used = _old_gen->used(); 461 462 bool run_verification = total_collections() >= VerifyGCStartAt; 463 464 bool prepared_for_verification = false; 465 bool collected_old = false; 466 467 if (do_young_collection) { 468 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { 469 prepare_for_verify(); 470 prepared_for_verification = true; 471 } 472 473 collect_generation(_young_gen, 474 full, 475 size, 476 is_tlab, 477 run_verification && VerifyGCLevel <= 0, 478 do_clear_all_soft_refs, 479 false); 480 481 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && 482 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { 483 // Allocation request was met by young GC. 484 size = 0; 485 } 486 } 487 488 bool must_restore_marks_for_biased_locking = false; 489 490 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) { 491 if (!complete) { 492 // The full_collections increment was missed above. 493 increment_total_full_collections(); 494 } 495 496 if (!prepared_for_verification && run_verification && 497 VerifyGCLevel <= 1 && VerifyBeforeGC) { 498 prepare_for_verify(); 499 } 500 501 if (do_young_collection) { 502 // We did a young GC. Need a new GC id for the old GC. 503 GCIdMarkAndRestore gc_id_mark; 504 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true); 505 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true); 506 } else { 507 // No young GC done. Use the same GC id as was set up earlier in this method. 508 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true); 509 } 510 511 must_restore_marks_for_biased_locking = true; 512 collected_old = true; 513 } 514 515 // Update "complete" boolean wrt what actually transpired -- 516 // for instance, a promotion failure could have led to 517 // a whole heap collection. 518 complete = complete || collected_old; 519 520 print_heap_change(young_prev_used, old_prev_used); 521 MetaspaceAux::print_metaspace_change(metadata_prev_used); 522 523 // Adjust generation sizes. 524 if (collected_old) { 525 _old_gen->compute_new_size(); 526 } 527 _young_gen->compute_new_size(); 528 529 if (complete) { 530 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 531 ClassLoaderDataGraph::purge(); 532 MetaspaceAux::verify_metrics(); 533 // Resize the metaspace capacity after full collections 534 MetaspaceGC::compute_new_size(); 535 update_full_collections_completed(); 536 } 537 538 // Track memory usage and detect low memory after GC finishes 539 MemoryService::track_memory_usage(); 540 541 gc_epilogue(complete); 542 543 if (must_restore_marks_for_biased_locking) { 544 BiasedLocking::restore_marks(); 545 } 546 } 547 548 print_heap_after_gc(); 549 550 #ifdef TRACESPINNING 551 ParallelTaskTerminator::print_termination_counts(); 552 #endif 553 } 554 555 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 556 return gen_policy()->satisfy_failed_allocation(size, is_tlab); 557 } 558 559 #ifdef ASSERT 560 class AssertNonScavengableClosure: public OopClosure { 561 public: 562 virtual void do_oop(oop* p) { 563 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), 564 "Referent should not be scavengable."); } 565 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 566 }; 567 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 568 #endif 569 570 void GenCollectedHeap::process_roots(StrongRootsScope* scope, 571 ScanningOption so, 572 OopClosure* strong_roots, 573 OopClosure* weak_roots, 574 CLDClosure* strong_cld_closure, 575 CLDClosure* weak_cld_closure, 576 CodeBlobToOopClosure* code_roots) { 577 // General roots. 578 assert(Threads::thread_claim_parity() != 0, "must have called prologue code"); 579 assert(code_roots != NULL, "code root closure should always be set"); 580 // _n_termination for _process_strong_tasks should be set up stream 581 // in a method not running in a GC worker. Otherwise the GC worker 582 // could be trying to change the termination condition while the task 583 // is executing in another GC worker. 584 585 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) { 586 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); 587 } 588 589 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway 590 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; 591 592 bool is_par = scope->n_threads() > 1; 593 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p); 594 595 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) { 596 Universe::oops_do(strong_roots); 597 } 598 // Global (strong) JNI handles 599 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) { 600 JNIHandles::oops_do(strong_roots); 601 } 602 603 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) { 604 ObjectSynchronizer::oops_do(strong_roots); 605 } 606 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) { 607 FlatProfiler::oops_do(strong_roots); 608 } 609 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) { 610 Management::oops_do(strong_roots); 611 } 612 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) { 613 JvmtiExport::oops_do(strong_roots); 614 } 615 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) { 616 AOTLoader::oops_do(strong_roots); 617 } 618 619 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) { 620 SystemDictionary::roots_oops_do(strong_roots, weak_roots); 621 } 622 623 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) { 624 if (so & SO_ScavengeCodeCache) { 625 assert(code_roots != NULL, "must supply closure for code cache"); 626 627 // We only visit parts of the CodeCache when scavenging. 628 CodeCache::scavenge_root_nmethods_do(code_roots); 629 } 630 if (so & SO_AllCodeCache) { 631 assert(code_roots != NULL, "must supply closure for code cache"); 632 633 // CMSCollector uses this to do intermediate-strength collections. 634 // We scan the entire code cache, since CodeCache::do_unloading is not called. 635 CodeCache::blobs_do(code_roots); 636 } 637 // Verify that the code cache contents are not subject to 638 // movement by a scavenging collection. 639 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); 640 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 641 } 642 } 643 644 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope, 645 OopClosure* root_closure) { 646 assert(root_closure != NULL, "Must be set"); 647 // All threads execute the following. A specific chunk of buckets 648 // from the StringTable are the individual tasks. 649 if (scope->n_threads() > 1) { 650 StringTable::possibly_parallel_oops_do(root_closure); 651 } else { 652 StringTable::oops_do(root_closure); 653 } 654 } 655 656 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope, 657 OopsInGenClosure* root_closure, 658 OopsInGenClosure* old_gen_closure, 659 CLDClosure* cld_closure) { 660 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations); 661 662 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure, 663 cld_closure, cld_closure, &mark_code_closure); 664 process_string_table_roots(scope, root_closure); 665 666 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 667 root_closure->reset_generation(); 668 } 669 670 // When collection is parallel, all threads get to cooperate to do 671 // old generation scanning. 672 old_gen_closure->set_generation(_old_gen); 673 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads()); 674 old_gen_closure->reset_generation(); 675 676 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 677 } 678 679 void GenCollectedHeap::cms_process_roots(StrongRootsScope* scope, 680 bool young_gen_as_roots, 681 ScanningOption so, 682 bool only_strong_roots, 683 OopsInGenClosure* root_closure, 684 CLDClosure* cld_closure) { 685 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations); 686 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 687 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 688 689 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 690 if (!only_strong_roots) { 691 process_string_table_roots(scope, root_closure); 692 } 693 694 if (young_gen_as_roots && 695 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 696 root_closure->set_generation(_young_gen); 697 _young_gen->oop_iterate(root_closure); 698 root_closure->reset_generation(); 699 } 700 701 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 702 } 703 704 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope, 705 bool is_adjust_phase, 706 ScanningOption so, 707 bool only_strong_roots, 708 OopsInGenClosure* root_closure, 709 CLDClosure* cld_closure) { 710 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase); 711 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 712 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 713 714 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 715 if (is_adjust_phase) { 716 // We never treat the string table as roots during marking 717 // for the full gc, so we only need to process it during 718 // the adjust phase. 719 process_string_table_roots(scope, root_closure); 720 } 721 722 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 723 } 724 725 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { 726 JNIHandles::weak_oops_do(root_closure); 727 _young_gen->ref_processor()->weak_oops_do(root_closure); 728 _old_gen->ref_processor()->weak_oops_do(root_closure); 729 } 730 731 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 732 void GenCollectedHeap:: \ 733 oop_since_save_marks_iterate(GenerationType gen, \ 734 OopClosureType* cur, \ 735 OopClosureType* older) { \ 736 if (gen == YoungGen) { \ 737 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 738 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \ 739 } else { \ 740 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 741 } \ 742 } 743 744 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) 745 746 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN 747 748 bool GenCollectedHeap::no_allocs_since_save_marks() { 749 return _young_gen->no_allocs_since_save_marks() && 750 _old_gen->no_allocs_since_save_marks(); 751 } 752 753 bool GenCollectedHeap::supports_inline_contig_alloc() const { 754 return _young_gen->supports_inline_contig_alloc(); 755 } 756 757 HeapWord* volatile* GenCollectedHeap::top_addr() const { 758 return _young_gen->top_addr(); 759 } 760 761 HeapWord** GenCollectedHeap::end_addr() const { 762 return _young_gen->end_addr(); 763 } 764 765 // public collection interfaces 766 767 void GenCollectedHeap::collect(GCCause::Cause cause) { 768 if (should_do_concurrent_full_gc(cause)) { 769 #if INCLUDE_ALL_GCS 770 // Mostly concurrent full collection. 771 collect_mostly_concurrent(cause); 772 #else // INCLUDE_ALL_GCS 773 ShouldNotReachHere(); 774 #endif // INCLUDE_ALL_GCS 775 } else if (cause == GCCause::_wb_young_gc) { 776 // Young collection for the WhiteBox API. 777 collect(cause, YoungGen); 778 } else { 779 #ifdef ASSERT 780 if (cause == GCCause::_scavenge_alot) { 781 // Young collection only. 782 collect(cause, YoungGen); 783 } else { 784 // Stop-the-world full collection. 785 collect(cause, OldGen); 786 } 787 #else 788 // Stop-the-world full collection. 789 collect(cause, OldGen); 790 #endif 791 } 792 } 793 794 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) { 795 // The caller doesn't have the Heap_lock 796 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 797 MutexLocker ml(Heap_lock); 798 collect_locked(cause, max_generation); 799 } 800 801 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 802 // The caller has the Heap_lock 803 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 804 collect_locked(cause, OldGen); 805 } 806 807 // this is the private collection interface 808 // The Heap_lock is expected to be held on entry. 809 810 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) { 811 // Read the GC count while holding the Heap_lock 812 unsigned int gc_count_before = total_collections(); 813 unsigned int full_gc_count_before = total_full_collections(); 814 { 815 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 816 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 817 cause, max_generation); 818 VMThread::execute(&op); 819 } 820 } 821 822 #if INCLUDE_ALL_GCS 823 bool GenCollectedHeap::create_cms_collector() { 824 825 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep, 826 "Unexpected generation kinds"); 827 // Skip two header words in the block content verification 828 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) 829 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type"); 830 CMSCollector* collector = 831 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen, 832 _rem_set, 833 _gen_policy->as_concurrent_mark_sweep_policy()); 834 835 if (collector == NULL || !collector->completed_initialization()) { 836 if (collector) { 837 delete collector; // Be nice in embedded situation 838 } 839 vm_shutdown_during_initialization("Could not create CMS collector"); 840 return false; 841 } 842 return true; // success 843 } 844 845 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { 846 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 847 848 MutexLocker ml(Heap_lock); 849 // Read the GC counts while holding the Heap_lock 850 unsigned int full_gc_count_before = total_full_collections(); 851 unsigned int gc_count_before = total_collections(); 852 { 853 MutexUnlocker mu(Heap_lock); 854 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 855 VMThread::execute(&op); 856 } 857 } 858 #endif // INCLUDE_ALL_GCS 859 860 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { 861 do_full_collection(clear_all_soft_refs, OldGen); 862 } 863 864 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 865 GenerationType last_generation) { 866 GenerationType local_last_generation; 867 if (!incremental_collection_will_fail(false /* don't consult_young */) && 868 gc_cause() == GCCause::_gc_locker) { 869 local_last_generation = YoungGen; 870 } else { 871 local_last_generation = last_generation; 872 } 873 874 do_collection(true, // full 875 clear_all_soft_refs, // clear_all_soft_refs 876 0, // size 877 false, // is_tlab 878 local_last_generation); // last_generation 879 // Hack XXX FIX ME !!! 880 // A scavenge may not have been attempted, or may have 881 // been attempted and failed, because the old gen was too full 882 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker && 883 incremental_collection_will_fail(false /* don't consult_young */)) { 884 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed"); 885 // This time allow the old gen to be collected as well 886 do_collection(true, // full 887 clear_all_soft_refs, // clear_all_soft_refs 888 0, // size 889 false, // is_tlab 890 OldGen); // last_generation 891 } 892 } 893 894 bool GenCollectedHeap::is_in_young(oop p) { 895 bool result = ((HeapWord*)p) < _old_gen->reserved().start(); 896 assert(result == _young_gen->is_in_reserved(p), 897 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)); 898 return result; 899 } 900 901 // Returns "TRUE" iff "p" points into the committed areas of the heap. 902 bool GenCollectedHeap::is_in(const void* p) const { 903 return _young_gen->is_in(p) || _old_gen->is_in(p); 904 } 905 906 #ifdef ASSERT 907 // Don't implement this by using is_in_young(). This method is used 908 // in some cases to check that is_in_young() is correct. 909 bool GenCollectedHeap::is_in_partial_collection(const void* p) { 910 assert(is_in_reserved(p) || p == NULL, 911 "Does not work if address is non-null and outside of the heap"); 912 return p < _young_gen->reserved().end() && p != NULL; 913 } 914 #endif 915 916 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) { 917 NoHeaderExtendedOopClosure no_header_cl(cl); 918 oop_iterate(&no_header_cl); 919 } 920 921 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) { 922 _young_gen->oop_iterate(cl); 923 _old_gen->oop_iterate(cl); 924 } 925 926 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 927 _young_gen->object_iterate(cl); 928 _old_gen->object_iterate(cl); 929 } 930 931 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { 932 _young_gen->safe_object_iterate(cl); 933 _old_gen->safe_object_iterate(cl); 934 } 935 936 Space* GenCollectedHeap::space_containing(const void* addr) const { 937 Space* res = _young_gen->space_containing(addr); 938 if (res != NULL) { 939 return res; 940 } 941 res = _old_gen->space_containing(addr); 942 assert(res != NULL, "Could not find containing space"); 943 return res; 944 } 945 946 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 947 assert(is_in_reserved(addr), "block_start of address outside of heap"); 948 if (_young_gen->is_in_reserved(addr)) { 949 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 950 return _young_gen->block_start(addr); 951 } 952 953 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 954 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 955 return _old_gen->block_start(addr); 956 } 957 958 size_t GenCollectedHeap::block_size(const HeapWord* addr) const { 959 assert(is_in_reserved(addr), "block_size of address outside of heap"); 960 if (_young_gen->is_in_reserved(addr)) { 961 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 962 return _young_gen->block_size(addr); 963 } 964 965 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 966 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 967 return _old_gen->block_size(addr); 968 } 969 970 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 971 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 972 assert(block_start(addr) == addr, "addr must be a block start"); 973 if (_young_gen->is_in_reserved(addr)) { 974 return _young_gen->block_is_obj(addr); 975 } 976 977 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 978 return _old_gen->block_is_obj(addr); 979 } 980 981 bool GenCollectedHeap::supports_tlab_allocation() const { 982 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 983 return _young_gen->supports_tlab_allocation(); 984 } 985 986 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 987 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 988 if (_young_gen->supports_tlab_allocation()) { 989 return _young_gen->tlab_capacity(); 990 } 991 return 0; 992 } 993 994 size_t GenCollectedHeap::tlab_used(Thread* thr) const { 995 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 996 if (_young_gen->supports_tlab_allocation()) { 997 return _young_gen->tlab_used(); 998 } 999 return 0; 1000 } 1001 1002 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1003 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1004 if (_young_gen->supports_tlab_allocation()) { 1005 return _young_gen->unsafe_max_tlab_alloc(); 1006 } 1007 return 0; 1008 } 1009 1010 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { 1011 bool gc_overhead_limit_was_exceeded; 1012 return gen_policy()->mem_allocate_work(size /* size */, 1013 true /* is_tlab */, 1014 &gc_overhead_limit_was_exceeded); 1015 } 1016 1017 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1018 // from the list headed by "*prev_ptr". 1019 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1020 bool first = true; 1021 size_t min_size = 0; // "first" makes this conceptually infinite. 1022 ScratchBlock **smallest_ptr, *smallest; 1023 ScratchBlock *cur = *prev_ptr; 1024 while (cur) { 1025 assert(*prev_ptr == cur, "just checking"); 1026 if (first || cur->num_words < min_size) { 1027 smallest_ptr = prev_ptr; 1028 smallest = cur; 1029 min_size = smallest->num_words; 1030 first = false; 1031 } 1032 prev_ptr = &cur->next; 1033 cur = cur->next; 1034 } 1035 smallest = *smallest_ptr; 1036 *smallest_ptr = smallest->next; 1037 return smallest; 1038 } 1039 1040 // Sort the scratch block list headed by res into decreasing size order, 1041 // and set "res" to the result. 1042 static void sort_scratch_list(ScratchBlock*& list) { 1043 ScratchBlock* sorted = NULL; 1044 ScratchBlock* unsorted = list; 1045 while (unsorted) { 1046 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1047 smallest->next = sorted; 1048 sorted = smallest; 1049 } 1050 list = sorted; 1051 } 1052 1053 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1054 size_t max_alloc_words) { 1055 ScratchBlock* res = NULL; 1056 _young_gen->contribute_scratch(res, requestor, max_alloc_words); 1057 _old_gen->contribute_scratch(res, requestor, max_alloc_words); 1058 sort_scratch_list(res); 1059 return res; 1060 } 1061 1062 void GenCollectedHeap::release_scratch() { 1063 _young_gen->reset_scratch(); 1064 _old_gen->reset_scratch(); 1065 } 1066 1067 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1068 void do_generation(Generation* gen) { 1069 gen->prepare_for_verify(); 1070 } 1071 }; 1072 1073 void GenCollectedHeap::prepare_for_verify() { 1074 ensure_parsability(false); // no need to retire TLABs 1075 GenPrepareForVerifyClosure blk; 1076 generation_iterate(&blk, false); 1077 } 1078 1079 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1080 bool old_to_young) { 1081 if (old_to_young) { 1082 cl->do_generation(_old_gen); 1083 cl->do_generation(_young_gen); 1084 } else { 1085 cl->do_generation(_young_gen); 1086 cl->do_generation(_old_gen); 1087 } 1088 } 1089 1090 bool GenCollectedHeap::is_maximal_no_gc() const { 1091 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); 1092 } 1093 1094 void GenCollectedHeap::save_marks() { 1095 _young_gen->save_marks(); 1096 _old_gen->save_marks(); 1097 } 1098 1099 GenCollectedHeap* GenCollectedHeap::heap() { 1100 CollectedHeap* heap = Universe::heap(); 1101 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1102 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap"); 1103 return (GenCollectedHeap*)heap; 1104 } 1105 1106 void GenCollectedHeap::prepare_for_compaction() { 1107 // Start by compacting into same gen. 1108 CompactPoint cp(_old_gen); 1109 _old_gen->prepare_for_compaction(&cp); 1110 _young_gen->prepare_for_compaction(&cp); 1111 } 1112 1113 void GenCollectedHeap::verify(VerifyOption option /* ignored */) { 1114 log_debug(gc, verify)("%s", _old_gen->name()); 1115 _old_gen->verify(); 1116 1117 log_debug(gc, verify)("%s", _old_gen->name()); 1118 _young_gen->verify(); 1119 1120 log_debug(gc, verify)("RemSet"); 1121 rem_set()->verify(); 1122 } 1123 1124 void GenCollectedHeap::print_on(outputStream* st) const { 1125 _young_gen->print_on(st); 1126 _old_gen->print_on(st); 1127 MetaspaceAux::print_on(st); 1128 } 1129 1130 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1131 if (workers() != NULL) { 1132 workers()->threads_do(tc); 1133 } 1134 #if INCLUDE_ALL_GCS 1135 if (UseConcMarkSweepGC) { 1136 ConcurrentMarkSweepThread::threads_do(tc); 1137 } 1138 #endif // INCLUDE_ALL_GCS 1139 } 1140 1141 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1142 #if INCLUDE_ALL_GCS 1143 if (UseConcMarkSweepGC) { 1144 workers()->print_worker_threads_on(st); 1145 ConcurrentMarkSweepThread::print_all_on(st); 1146 } 1147 #endif // INCLUDE_ALL_GCS 1148 } 1149 1150 void GenCollectedHeap::print_on_error(outputStream* st) const { 1151 this->CollectedHeap::print_on_error(st); 1152 1153 #if INCLUDE_ALL_GCS 1154 if (UseConcMarkSweepGC) { 1155 st->cr(); 1156 CMSCollector::print_on_error(st); 1157 } 1158 #endif // INCLUDE_ALL_GCS 1159 } 1160 1161 void GenCollectedHeap::print_tracing_info() const { 1162 if (TraceYoungGenTime) { 1163 _young_gen->print_summary_info(); 1164 } 1165 if (TraceOldGenTime) { 1166 _old_gen->print_summary_info(); 1167 } 1168 } 1169 1170 void GenCollectedHeap::print_heap_change(size_t young_prev_used, size_t old_prev_used) const { 1171 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)", 1172 _young_gen->short_name(), young_prev_used / K, _young_gen->used() /K, _young_gen->capacity() /K); 1173 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)", 1174 _old_gen->short_name(), old_prev_used / K, _old_gen->used() /K, _old_gen->capacity() /K); 1175 } 1176 1177 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1178 private: 1179 bool _full; 1180 public: 1181 void do_generation(Generation* gen) { 1182 gen->gc_prologue(_full); 1183 } 1184 GenGCPrologueClosure(bool full) : _full(full) {}; 1185 }; 1186 1187 void GenCollectedHeap::gc_prologue(bool full) { 1188 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1189 1190 always_do_update_barrier = false; 1191 // Fill TLAB's and such 1192 CollectedHeap::accumulate_statistics_all_tlabs(); 1193 ensure_parsability(true); // retire TLABs 1194 1195 // Walk generations 1196 GenGCPrologueClosure blk(full); 1197 generation_iterate(&blk, false); // not old-to-young. 1198 }; 1199 1200 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1201 private: 1202 bool _full; 1203 public: 1204 void do_generation(Generation* gen) { 1205 gen->gc_epilogue(_full); 1206 } 1207 GenGCEpilogueClosure(bool full) : _full(full) {}; 1208 }; 1209 1210 void GenCollectedHeap::gc_epilogue(bool full) { 1211 #if defined(COMPILER2) || INCLUDE_JVMCI 1212 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1213 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1214 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1215 #endif /* COMPILER2 || INCLUDE_JVMCI */ 1216 1217 resize_all_tlabs(); 1218 1219 GenGCEpilogueClosure blk(full); 1220 generation_iterate(&blk, false); // not old-to-young. 1221 1222 if (!CleanChunkPoolAsync) { 1223 Chunk::clean_chunk_pool(); 1224 } 1225 1226 MetaspaceCounters::update_performance_counters(); 1227 CompressedClassSpaceCounters::update_performance_counters(); 1228 1229 always_do_update_barrier = UseConcMarkSweepGC; 1230 }; 1231 1232 #ifndef PRODUCT 1233 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1234 private: 1235 public: 1236 void do_generation(Generation* gen) { 1237 gen->record_spaces_top(); 1238 } 1239 }; 1240 1241 void GenCollectedHeap::record_gen_tops_before_GC() { 1242 if (ZapUnusedHeapArea) { 1243 GenGCSaveTopsBeforeGCClosure blk; 1244 generation_iterate(&blk, false); // not old-to-young. 1245 } 1246 } 1247 #endif // not PRODUCT 1248 1249 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1250 public: 1251 void do_generation(Generation* gen) { 1252 gen->ensure_parsability(); 1253 } 1254 }; 1255 1256 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1257 CollectedHeap::ensure_parsability(retire_tlabs); 1258 GenEnsureParsabilityClosure ep_cl; 1259 generation_iterate(&ep_cl, false); 1260 } 1261 1262 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, 1263 oop obj, 1264 size_t obj_size) { 1265 guarantee(old_gen == _old_gen, "We only get here with an old generation"); 1266 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1267 HeapWord* result = NULL; 1268 1269 result = old_gen->expand_and_allocate(obj_size, false); 1270 1271 if (result != NULL) { 1272 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 1273 } 1274 return oop(result); 1275 } 1276 1277 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1278 jlong _time; // in ms 1279 jlong _now; // in ms 1280 1281 public: 1282 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1283 1284 jlong time() { return _time; } 1285 1286 void do_generation(Generation* gen) { 1287 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1288 } 1289 }; 1290 1291 jlong GenCollectedHeap::millis_since_last_gc() { 1292 // javaTimeNanos() is guaranteed to be monotonically non-decreasing 1293 // provided the underlying platform provides such a time source 1294 // (and it is bug free). So we still have to guard against getting 1295 // back a time later than 'now'. 1296 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 1297 GenTimeOfLastGCClosure tolgc_cl(now); 1298 // iterate over generations getting the oldest 1299 // time that a generation was collected 1300 generation_iterate(&tolgc_cl, false); 1301 1302 jlong retVal = now - tolgc_cl.time(); 1303 if (retVal < 0) { 1304 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT 1305 ". returning zero instead.", retVal); 1306 return 0; 1307 } 1308 return retVal; 1309 } 1310 1311 void GenCollectedHeap::stop() { 1312 #if INCLUDE_ALL_GCS 1313 if (UseConcMarkSweepGC) { 1314 ConcurrentMarkSweepThread::cmst()->stop(); 1315 } 1316 #endif 1317 }