1 /* 2 * Copyright (c) 2000, 2016, 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/macros.hpp" 57 #include "utilities/stack.inline.hpp" 58 #include "utilities/vmError.hpp" 59 #if INCLUDE_ALL_GCS 60 #include "gc/cms/concurrentMarkSweepThread.hpp" 61 #include "gc/cms/vmCMSOperations.hpp" 62 #endif // INCLUDE_ALL_GCS 63 64 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) 65 66 // The set of potentially parallel tasks in root scanning. 67 enum GCH_strong_roots_tasks { 68 GCH_PS_Universe_oops_do, 69 GCH_PS_JNIHandles_oops_do, 70 GCH_PS_ObjectSynchronizer_oops_do, 71 GCH_PS_FlatProfiler_oops_do, 72 GCH_PS_Management_oops_do, 73 GCH_PS_SystemDictionary_oops_do, 74 GCH_PS_ClassLoaderDataGraph_oops_do, 75 GCH_PS_jvmti_oops_do, 76 GCH_PS_CodeCache_oops_do, 77 GCH_PS_aot_oops_do, 78 GCH_PS_younger_gens, 79 // Leave this one last. 80 GCH_PS_NumElements 81 }; 82 83 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) : 84 CollectedHeap(), 85 _rem_set(NULL), 86 _gen_policy(policy), 87 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)), 88 _full_collections_completed(0) 89 { 90 assert(policy != NULL, "Sanity check"); 91 if (UseConcMarkSweepGC) { 92 _workers = new WorkGang("GC Thread", ParallelGCThreads, 93 /* are_GC_task_threads */true, 94 /* are_ConcurrentGC_threads */false); 95 _workers->initialize_workers(); 96 } else { 97 // Serial GC does not use workers. 98 _workers = NULL; 99 } 100 } 101 102 jint GenCollectedHeap::initialize() { 103 CollectedHeap::pre_initialize(); 104 105 // While there are no constraints in the GC code that HeapWordSize 106 // be any particular value, there are multiple other areas in the 107 // system which believe this to be true (e.g. oop->object_size in some 108 // cases incorrectly returns the size in wordSize units rather than 109 // HeapWordSize). 110 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); 111 112 // Allocate space for the heap. 113 114 char* heap_address; 115 ReservedSpace heap_rs; 116 117 size_t heap_alignment = collector_policy()->heap_alignment(); 118 119 heap_address = allocate(heap_alignment, &heap_rs); 120 121 if (!heap_rs.is_reserved()) { 122 vm_shutdown_during_initialization( 123 "Could not reserve enough space for object heap"); 124 return JNI_ENOMEM; 125 } 126 127 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size())); 128 129 _rem_set = collector_policy()->create_rem_set(reserved_region()); 130 set_barrier_set(rem_set()->bs()); 131 132 ReservedSpace young_rs = heap_rs.first_part(gen_policy()->young_gen_spec()->max_size(), false, false); 133 _young_gen = gen_policy()->young_gen_spec()->init(young_rs, rem_set()); 134 heap_rs = heap_rs.last_part(gen_policy()->young_gen_spec()->max_size()); 135 136 ReservedSpace old_rs = heap_rs.first_part(gen_policy()->old_gen_spec()->max_size(), false, false); 137 _old_gen = gen_policy()->old_gen_spec()->init(old_rs, rem_set()); 138 clear_incremental_collection_failed(); 139 140 #if INCLUDE_ALL_GCS 141 // If we are running CMS, create the collector responsible 142 // for collecting the CMS generations. 143 if (collector_policy()->is_concurrent_mark_sweep_policy()) { 144 bool success = create_cms_collector(); 145 if (!success) return JNI_ENOMEM; 146 } 147 #endif // INCLUDE_ALL_GCS 148 149 return JNI_OK; 150 } 151 152 char* GenCollectedHeap::allocate(size_t alignment, 153 ReservedSpace* heap_rs){ 154 // Now figure out the total size. 155 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size(); 156 assert(alignment % pageSize == 0, "Must be"); 157 158 GenerationSpec* young_spec = gen_policy()->young_gen_spec(); 159 GenerationSpec* old_spec = gen_policy()->old_gen_spec(); 160 161 // Check for overflow. 162 size_t total_reserved = young_spec->max_size() + old_spec->max_size(); 163 if (total_reserved < young_spec->max_size()) { 164 vm_exit_during_initialization("The size of the object heap + VM data exceeds " 165 "the maximum representable size"); 166 } 167 assert(total_reserved % alignment == 0, 168 "Gen size; total_reserved=" SIZE_FORMAT ", alignment=" 169 SIZE_FORMAT, total_reserved, alignment); 170 171 *heap_rs = Universe::reserve_heap(total_reserved, alignment); 172 173 os::trace_page_sizes("Heap", 174 collector_policy()->min_heap_byte_size(), 175 total_reserved, 176 alignment, 177 heap_rs->base(), 178 heap_rs->size()); 179 180 return heap_rs->base(); 181 } 182 183 void GenCollectedHeap::post_initialize() { 184 ref_processing_init(); 185 assert((_young_gen->kind() == Generation::DefNew) || 186 (_young_gen->kind() == Generation::ParNew), 187 "Wrong youngest generation type"); 188 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; 189 190 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep || 191 _old_gen->kind() == Generation::MarkSweepCompact, 192 "Wrong generation kind"); 193 194 _gen_policy->initialize_size_policy(def_new_gen->eden()->capacity(), 195 _old_gen->capacity(), 196 def_new_gen->from()->capacity()); 197 _gen_policy->initialize_gc_policy_counters(); 198 } 199 200 void GenCollectedHeap::ref_processing_init() { 201 _young_gen->ref_processor_init(); 202 _old_gen->ref_processor_init(); 203 } 204 205 size_t GenCollectedHeap::capacity() const { 206 return _young_gen->capacity() + _old_gen->capacity(); 207 } 208 209 size_t GenCollectedHeap::used() const { 210 return _young_gen->used() + _old_gen->used(); 211 } 212 213 void GenCollectedHeap::save_used_regions() { 214 _old_gen->save_used_region(); 215 _young_gen->save_used_region(); 216 } 217 218 size_t GenCollectedHeap::max_capacity() const { 219 return _young_gen->max_capacity() + _old_gen->max_capacity(); 220 } 221 222 // Update the _full_collections_completed counter 223 // at the end of a stop-world full GC. 224 unsigned int GenCollectedHeap::update_full_collections_completed() { 225 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 226 assert(_full_collections_completed <= _total_full_collections, 227 "Can't complete more collections than were started"); 228 _full_collections_completed = _total_full_collections; 229 ml.notify_all(); 230 return _full_collections_completed; 231 } 232 233 // Update the _full_collections_completed counter, as appropriate, 234 // at the end of a concurrent GC cycle. Note the conditional update 235 // below to allow this method to be called by a concurrent collector 236 // without synchronizing in any manner with the VM thread (which 237 // may already have initiated a STW full collection "concurrently"). 238 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 239 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 240 assert((_full_collections_completed <= _total_full_collections) && 241 (count <= _total_full_collections), 242 "Can't complete more collections than were started"); 243 if (count > _full_collections_completed) { 244 _full_collections_completed = count; 245 ml.notify_all(); 246 } 247 return _full_collections_completed; 248 } 249 250 251 #ifndef PRODUCT 252 // Override of memory state checking method in CollectedHeap: 253 // Some collectors (CMS for example) can't have badHeapWordVal written 254 // in the first two words of an object. (For instance , in the case of 255 // CMS these words hold state used to synchronize between certain 256 // (concurrent) GC steps and direct allocating mutators.) 257 // The skip_header_HeapWords() method below, allows us to skip 258 // over the requisite number of HeapWord's. Note that (for 259 // generational collectors) this means that those many words are 260 // skipped in each object, irrespective of the generation in which 261 // that object lives. The resultant loss of precision seems to be 262 // harmless and the pain of avoiding that imprecision appears somewhat 263 // higher than we are prepared to pay for such rudimentary debugging 264 // support. 265 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, 266 size_t size) { 267 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 268 // We are asked to check a size in HeapWords, 269 // but the memory is mangled in juint words. 270 juint* start = (juint*) (addr + skip_header_HeapWords()); 271 juint* end = (juint*) (addr + size); 272 for (juint* slot = start; slot < end; slot += 1) { 273 assert(*slot == badHeapWordVal, 274 "Found non badHeapWordValue in pre-allocation check"); 275 } 276 } 277 } 278 #endif 279 280 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 281 bool is_tlab, 282 bool first_only) { 283 HeapWord* res = NULL; 284 285 if (_young_gen->should_allocate(size, is_tlab)) { 286 res = _young_gen->allocate(size, is_tlab); 287 if (res != NULL || first_only) { 288 return res; 289 } 290 } 291 292 if (_old_gen->should_allocate(size, is_tlab)) { 293 res = _old_gen->allocate(size, is_tlab); 294 } 295 296 return res; 297 } 298 299 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 300 bool* gc_overhead_limit_was_exceeded) { 301 return gen_policy()->mem_allocate_work(size, 302 false /* is_tlab */, 303 gc_overhead_limit_was_exceeded); 304 } 305 306 bool GenCollectedHeap::must_clear_all_soft_refs() { 307 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs || 308 _gc_cause == GCCause::_wb_full_gc; 309 } 310 311 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { 312 if (!UseConcMarkSweepGC) { 313 return false; 314 } 315 316 switch (cause) { 317 case GCCause::_gc_locker: return GCLockerInvokesConcurrent; 318 case GCCause::_java_lang_system_gc: 319 case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent; 320 default: return false; 321 } 322 } 323 324 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, 325 bool is_tlab, bool run_verification, bool clear_soft_refs, 326 bool restore_marks_for_biased_locking) { 327 FormatBuffer<> title("Collect gen: %s", gen->short_name()); 328 GCTraceTime(Trace, gc, phases) t1(title); 329 TraceCollectorStats tcs(gen->counters()); 330 TraceMemoryManagerStats tmms(gen->kind(),gc_cause()); 331 332 gen->stat_record()->invocations++; 333 gen->stat_record()->accumulated_time.start(); 334 335 // Must be done anew before each collection because 336 // a previous collection will do mangling and will 337 // change top of some spaces. 338 record_gen_tops_before_GC(); 339 340 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize); 341 342 if (run_verification && VerifyBeforeGC) { 343 HandleMark hm; // Discard invalid handles created during verification 344 Universe::verify("Before GC"); 345 } 346 COMPILER2_PRESENT(DerivedPointerTable::clear()); 347 348 if (restore_marks_for_biased_locking) { 349 // We perform this mark word preservation work lazily 350 // because it's only at this point that we know whether we 351 // absolutely have to do it; we want to avoid doing it for 352 // scavenge-only collections where it's unnecessary 353 BiasedLocking::preserve_marks(); 354 } 355 356 // Do collection work 357 { 358 // Note on ref discovery: For what appear to be historical reasons, 359 // GCH enables and disabled (by enqueing) refs discovery. 360 // In the future this should be moved into the generation's 361 // collect method so that ref discovery and enqueueing concerns 362 // are local to a generation. The collect method could return 363 // an appropriate indication in the case that notification on 364 // the ref lock was needed. This will make the treatment of 365 // weak refs more uniform (and indeed remove such concerns 366 // from GCH). XXX 367 368 HandleMark hm; // Discard invalid handles created during gc 369 save_marks(); // save marks for all gens 370 // We want to discover references, but not process them yet. 371 // This mode is disabled in process_discovered_references if the 372 // generation does some collection work, or in 373 // enqueue_discovered_references if the generation returns 374 // without doing any work. 375 ReferenceProcessor* rp = gen->ref_processor(); 376 // If the discovery of ("weak") refs in this generation is 377 // atomic wrt other collectors in this configuration, we 378 // are guaranteed to have empty discovered ref lists. 379 if (rp->discovery_is_atomic()) { 380 rp->enable_discovery(); 381 rp->setup_policy(clear_soft_refs); 382 } else { 383 // collect() below will enable discovery as appropriate 384 } 385 gen->collect(full, clear_soft_refs, size, is_tlab); 386 if (!rp->enqueuing_is_done()) { 387 rp->enqueue_discovered_references(); 388 } else { 389 rp->set_enqueuing_is_done(false); 390 } 391 rp->verify_no_references_recorded(); 392 } 393 394 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 395 396 gen->stat_record()->accumulated_time.stop(); 397 398 update_gc_stats(gen, full); 399 400 if (run_verification && VerifyAfterGC) { 401 HandleMark hm; // Discard invalid handles created during verification 402 Universe::verify("After GC"); 403 } 404 } 405 406 void GenCollectedHeap::do_collection(bool full, 407 bool clear_all_soft_refs, 408 size_t size, 409 bool is_tlab, 410 GenerationType max_generation) { 411 ResourceMark rm; 412 DEBUG_ONLY(Thread* my_thread = Thread::current();) 413 414 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 415 assert(my_thread->is_VM_thread() || 416 my_thread->is_ConcurrentGC_thread(), 417 "incorrect thread type capability"); 418 assert(Heap_lock->is_locked(), 419 "the requesting thread should have the Heap_lock"); 420 guarantee(!is_gc_active(), "collection is not reentrant"); 421 422 if (GCLocker::check_active_before_gc()) { 423 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 424 } 425 426 GCIdMarkAndRestore gc_id_mark; 427 428 const bool do_clear_all_soft_refs = clear_all_soft_refs || 429 collector_policy()->should_clear_all_soft_refs(); 430 431 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); 432 433 const size_t metadata_prev_used = MetaspaceAux::used_bytes(); 434 435 print_heap_before_gc(); 436 437 { 438 FlagSetting fl(_is_gc_active, true); 439 440 bool complete = full && (max_generation == OldGen); 441 bool old_collects_young = complete && !ScavengeBeforeFullGC; 442 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab); 443 444 FormatBuffer<> gc_string("%s", "Pause "); 445 if (do_young_collection) { 446 gc_string.append("Young"); 447 } else { 448 gc_string.append("Full"); 449 } 450 451 GCTraceCPUTime tcpu; 452 GCTraceTime(Info, gc) t(gc_string, NULL, gc_cause(), true); 453 454 gc_prologue(complete); 455 increment_total_collections(complete); 456 457 size_t young_prev_used = _young_gen->used(); 458 size_t old_prev_used = _old_gen->used(); 459 460 bool run_verification = total_collections() >= VerifyGCStartAt; 461 462 bool prepared_for_verification = false; 463 bool collected_old = false; 464 465 if (do_young_collection) { 466 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { 467 prepare_for_verify(); 468 prepared_for_verification = true; 469 } 470 471 collect_generation(_young_gen, 472 full, 473 size, 474 is_tlab, 475 run_verification && VerifyGCLevel <= 0, 476 do_clear_all_soft_refs, 477 false); 478 479 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && 480 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { 481 // Allocation request was met by young GC. 482 size = 0; 483 } 484 } 485 486 bool must_restore_marks_for_biased_locking = false; 487 488 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) { 489 if (!complete) { 490 // The full_collections increment was missed above. 491 increment_total_full_collections(); 492 } 493 494 if (!prepared_for_verification && run_verification && 495 VerifyGCLevel <= 1 && VerifyBeforeGC) { 496 prepare_for_verify(); 497 } 498 499 if (do_young_collection) { 500 // We did a young GC. Need a new GC id for the old GC. 501 GCIdMarkAndRestore gc_id_mark; 502 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true); 503 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true); 504 } else { 505 // No young GC done. Use the same GC id as was set up earlier in this method. 506 collect_generation(_old_gen, full, size, is_tlab, run_verification && VerifyGCLevel <= 1, do_clear_all_soft_refs, true); 507 } 508 509 must_restore_marks_for_biased_locking = true; 510 collected_old = true; 511 } 512 513 // Update "complete" boolean wrt what actually transpired -- 514 // for instance, a promotion failure could have led to 515 // a whole heap collection. 516 complete = complete || collected_old; 517 518 print_heap_change(young_prev_used, old_prev_used); 519 MetaspaceAux::print_metaspace_change(metadata_prev_used); 520 521 // Adjust generation sizes. 522 if (collected_old) { 523 _old_gen->compute_new_size(); 524 } 525 _young_gen->compute_new_size(); 526 527 if (complete) { 528 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 529 ClassLoaderDataGraph::purge(); 530 MetaspaceAux::verify_metrics(); 531 // Resize the metaspace capacity after full collections 532 MetaspaceGC::compute_new_size(); 533 update_full_collections_completed(); 534 } 535 536 // Track memory usage and detect low memory after GC finishes 537 MemoryService::track_memory_usage(); 538 539 gc_epilogue(complete); 540 541 if (must_restore_marks_for_biased_locking) { 542 BiasedLocking::restore_marks(); 543 } 544 } 545 546 print_heap_after_gc(); 547 548 #ifdef TRACESPINNING 549 ParallelTaskTerminator::print_termination_counts(); 550 #endif 551 } 552 553 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 554 return gen_policy()->satisfy_failed_allocation(size, is_tlab); 555 } 556 557 #ifdef ASSERT 558 class AssertNonScavengableClosure: public OopClosure { 559 public: 560 virtual void do_oop(oop* p) { 561 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), 562 "Referent should not be scavengable."); } 563 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 564 }; 565 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 566 #endif 567 568 void GenCollectedHeap::process_roots(StrongRootsScope* scope, 569 ScanningOption so, 570 OopClosure* strong_roots, 571 OopClosure* weak_roots, 572 CLDClosure* strong_cld_closure, 573 CLDClosure* weak_cld_closure, 574 CodeBlobToOopClosure* code_roots) { 575 // General roots. 576 assert(Threads::thread_claim_parity() != 0, "must have called prologue code"); 577 assert(code_roots != NULL, "code root closure should always be set"); 578 // _n_termination for _process_strong_tasks should be set up stream 579 // in a method not running in a GC worker. Otherwise the GC worker 580 // could be trying to change the termination condition while the task 581 // is executing in another GC worker. 582 583 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) { 584 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); 585 } 586 587 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway 588 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; 589 590 bool is_par = scope->n_threads() > 1; 591 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p); 592 593 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) { 594 Universe::oops_do(strong_roots); 595 } 596 // Global (strong) JNI handles 597 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) { 598 JNIHandles::oops_do(strong_roots); 599 } 600 601 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) { 602 ObjectSynchronizer::oops_do(strong_roots); 603 } 604 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) { 605 FlatProfiler::oops_do(strong_roots); 606 } 607 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) { 608 Management::oops_do(strong_roots); 609 } 610 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) { 611 JvmtiExport::oops_do(strong_roots); 612 } 613 if (UseAOT && !_process_strong_tasks->is_task_claimed(GCH_PS_aot_oops_do)) { 614 AOTLoader::oops_do(strong_roots); 615 } 616 617 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) { 618 SystemDictionary::roots_oops_do(strong_roots, weak_roots); 619 } 620 621 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) { 622 if (so & SO_ScavengeCodeCache) { 623 assert(code_roots != NULL, "must supply closure for code cache"); 624 625 // We only visit parts of the CodeCache when scavenging. 626 CodeCache::scavenge_root_nmethods_do(code_roots); 627 } 628 if (so & SO_AllCodeCache) { 629 assert(code_roots != NULL, "must supply closure for code cache"); 630 631 // CMSCollector uses this to do intermediate-strength collections. 632 // We scan the entire code cache, since CodeCache::do_unloading is not called. 633 CodeCache::blobs_do(code_roots); 634 } 635 // Verify that the code cache contents are not subject to 636 // movement by a scavenging collection. 637 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); 638 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 639 } 640 } 641 642 void GenCollectedHeap::process_string_table_roots(StrongRootsScope* scope, 643 OopClosure* root_closure) { 644 assert(root_closure != NULL, "Must be set"); 645 // All threads execute the following. A specific chunk of buckets 646 // from the StringTable are the individual tasks. 647 if (scope->n_threads() > 1) { 648 StringTable::possibly_parallel_oops_do(root_closure); 649 } else { 650 StringTable::oops_do(root_closure); 651 } 652 } 653 654 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope, 655 OopsInGenClosure* root_closure, 656 OopsInGenClosure* old_gen_closure, 657 CLDClosure* cld_closure) { 658 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations); 659 660 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure, 661 cld_closure, cld_closure, &mark_code_closure); 662 process_string_table_roots(scope, root_closure); 663 664 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 665 root_closure->reset_generation(); 666 } 667 668 // When collection is parallel, all threads get to cooperate to do 669 // old generation scanning. 670 old_gen_closure->set_generation(_old_gen); 671 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads()); 672 old_gen_closure->reset_generation(); 673 674 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 675 } 676 677 void GenCollectedHeap::cms_process_roots(StrongRootsScope* scope, 678 bool young_gen_as_roots, 679 ScanningOption so, 680 bool only_strong_roots, 681 OopsInGenClosure* root_closure, 682 CLDClosure* cld_closure) { 683 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations); 684 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 685 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 686 687 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 688 if (!only_strong_roots) { 689 process_string_table_roots(scope, root_closure); 690 } 691 692 if (young_gen_as_roots && 693 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 694 root_closure->set_generation(_young_gen); 695 _young_gen->oop_iterate(root_closure); 696 root_closure->reset_generation(); 697 } 698 699 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 700 } 701 702 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope, 703 bool is_adjust_phase, 704 ScanningOption so, 705 bool only_strong_roots, 706 OopsInGenClosure* root_closure, 707 CLDClosure* cld_closure) { 708 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase); 709 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 710 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 711 712 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 713 if (is_adjust_phase) { 714 // We never treat the string table as roots during marking 715 // for the full gc, so we only need to process it during 716 // the adjust phase. 717 process_string_table_roots(scope, root_closure); 718 } 719 720 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 721 } 722 723 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { 724 JNIHandles::weak_oops_do(root_closure); 725 _young_gen->ref_processor()->weak_oops_do(root_closure); 726 _old_gen->ref_processor()->weak_oops_do(root_closure); 727 } 728 729 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 730 void GenCollectedHeap:: \ 731 oop_since_save_marks_iterate(GenerationType gen, \ 732 OopClosureType* cur, \ 733 OopClosureType* older) { \ 734 if (gen == YoungGen) { \ 735 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 736 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \ 737 } else { \ 738 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 739 } \ 740 } 741 742 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) 743 744 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN 745 746 bool GenCollectedHeap::no_allocs_since_save_marks() { 747 return _young_gen->no_allocs_since_save_marks() && 748 _old_gen->no_allocs_since_save_marks(); 749 } 750 751 bool GenCollectedHeap::supports_inline_contig_alloc() const { 752 return _young_gen->supports_inline_contig_alloc(); 753 } 754 755 HeapWord* volatile* GenCollectedHeap::top_addr() const { 756 return _young_gen->top_addr(); 757 } 758 759 HeapWord** GenCollectedHeap::end_addr() const { 760 return _young_gen->end_addr(); 761 } 762 763 // public collection interfaces 764 765 void GenCollectedHeap::collect(GCCause::Cause cause) { 766 if (should_do_concurrent_full_gc(cause)) { 767 #if INCLUDE_ALL_GCS 768 // Mostly concurrent full collection. 769 collect_mostly_concurrent(cause); 770 #else // INCLUDE_ALL_GCS 771 ShouldNotReachHere(); 772 #endif // INCLUDE_ALL_GCS 773 } else if (cause == GCCause::_wb_young_gc) { 774 // Young collection for the WhiteBox API. 775 collect(cause, YoungGen); 776 } else { 777 #ifdef ASSERT 778 if (cause == GCCause::_scavenge_alot) { 779 // Young collection only. 780 collect(cause, YoungGen); 781 } else { 782 // Stop-the-world full collection. 783 collect(cause, OldGen); 784 } 785 #else 786 // Stop-the-world full collection. 787 collect(cause, OldGen); 788 #endif 789 } 790 } 791 792 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) { 793 // The caller doesn't have the Heap_lock 794 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 795 MutexLocker ml(Heap_lock); 796 collect_locked(cause, max_generation); 797 } 798 799 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 800 // The caller has the Heap_lock 801 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 802 collect_locked(cause, OldGen); 803 } 804 805 // this is the private collection interface 806 // The Heap_lock is expected to be held on entry. 807 808 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) { 809 // Read the GC count while holding the Heap_lock 810 unsigned int gc_count_before = total_collections(); 811 unsigned int full_gc_count_before = total_full_collections(); 812 { 813 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 814 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 815 cause, max_generation); 816 VMThread::execute(&op); 817 } 818 } 819 820 #if INCLUDE_ALL_GCS 821 bool GenCollectedHeap::create_cms_collector() { 822 823 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep, 824 "Unexpected generation kinds"); 825 // Skip two header words in the block content verification 826 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) 827 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type"); 828 CMSCollector* collector = 829 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen, 830 _rem_set, 831 _gen_policy->as_concurrent_mark_sweep_policy()); 832 833 if (collector == NULL || !collector->completed_initialization()) { 834 if (collector) { 835 delete collector; // Be nice in embedded situation 836 } 837 vm_shutdown_during_initialization("Could not create CMS collector"); 838 return false; 839 } 840 return true; // success 841 } 842 843 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { 844 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 845 846 MutexLocker ml(Heap_lock); 847 // Read the GC counts while holding the Heap_lock 848 unsigned int full_gc_count_before = total_full_collections(); 849 unsigned int gc_count_before = total_collections(); 850 { 851 MutexUnlocker mu(Heap_lock); 852 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 853 VMThread::execute(&op); 854 } 855 } 856 #endif // INCLUDE_ALL_GCS 857 858 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { 859 do_full_collection(clear_all_soft_refs, OldGen); 860 } 861 862 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 863 GenerationType last_generation) { 864 GenerationType local_last_generation; 865 if (!incremental_collection_will_fail(false /* don't consult_young */) && 866 gc_cause() == GCCause::_gc_locker) { 867 local_last_generation = YoungGen; 868 } else { 869 local_last_generation = last_generation; 870 } 871 872 do_collection(true, // full 873 clear_all_soft_refs, // clear_all_soft_refs 874 0, // size 875 false, // is_tlab 876 local_last_generation); // last_generation 877 // Hack XXX FIX ME !!! 878 // A scavenge may not have been attempted, or may have 879 // been attempted and failed, because the old gen was too full 880 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker && 881 incremental_collection_will_fail(false /* don't consult_young */)) { 882 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed"); 883 // This time allow the old gen to be collected as well 884 do_collection(true, // full 885 clear_all_soft_refs, // clear_all_soft_refs 886 0, // size 887 false, // is_tlab 888 OldGen); // last_generation 889 } 890 } 891 892 bool GenCollectedHeap::is_in_young(oop p) { 893 bool result = ((HeapWord*)p) < _old_gen->reserved().start(); 894 assert(result == _young_gen->is_in_reserved(p), 895 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)); 896 return result; 897 } 898 899 // Returns "TRUE" iff "p" points into the committed areas of the heap. 900 bool GenCollectedHeap::is_in(const void* p) const { 901 return _young_gen->is_in(p) || _old_gen->is_in(p); 902 } 903 904 #ifdef ASSERT 905 // Don't implement this by using is_in_young(). This method is used 906 // in some cases to check that is_in_young() is correct. 907 bool GenCollectedHeap::is_in_partial_collection(const void* p) { 908 assert(is_in_reserved(p) || p == NULL, 909 "Does not work if address is non-null and outside of the heap"); 910 return p < _young_gen->reserved().end() && p != NULL; 911 } 912 #endif 913 914 void GenCollectedHeap::oop_iterate_no_header(OopClosure* cl) { 915 NoHeaderExtendedOopClosure no_header_cl(cl); 916 oop_iterate(&no_header_cl); 917 } 918 919 void GenCollectedHeap::oop_iterate(ExtendedOopClosure* cl) { 920 _young_gen->oop_iterate(cl); 921 _old_gen->oop_iterate(cl); 922 } 923 924 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 925 _young_gen->object_iterate(cl); 926 _old_gen->object_iterate(cl); 927 } 928 929 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { 930 _young_gen->safe_object_iterate(cl); 931 _old_gen->safe_object_iterate(cl); 932 } 933 934 Space* GenCollectedHeap::space_containing(const void* addr) const { 935 Space* res = _young_gen->space_containing(addr); 936 if (res != NULL) { 937 return res; 938 } 939 res = _old_gen->space_containing(addr); 940 assert(res != NULL, "Could not find containing space"); 941 return res; 942 } 943 944 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 945 assert(is_in_reserved(addr), "block_start of address outside of heap"); 946 if (_young_gen->is_in_reserved(addr)) { 947 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 948 return _young_gen->block_start(addr); 949 } 950 951 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 952 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 953 return _old_gen->block_start(addr); 954 } 955 956 size_t GenCollectedHeap::block_size(const HeapWord* addr) const { 957 assert(is_in_reserved(addr), "block_size of address outside of heap"); 958 if (_young_gen->is_in_reserved(addr)) { 959 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 960 return _young_gen->block_size(addr); 961 } 962 963 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 964 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 965 return _old_gen->block_size(addr); 966 } 967 968 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 969 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 970 assert(block_start(addr) == addr, "addr must be a block start"); 971 if (_young_gen->is_in_reserved(addr)) { 972 return _young_gen->block_is_obj(addr); 973 } 974 975 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 976 return _old_gen->block_is_obj(addr); 977 } 978 979 bool GenCollectedHeap::supports_tlab_allocation() const { 980 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 981 return _young_gen->supports_tlab_allocation(); 982 } 983 984 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 985 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 986 if (_young_gen->supports_tlab_allocation()) { 987 return _young_gen->tlab_capacity(); 988 } 989 return 0; 990 } 991 992 size_t GenCollectedHeap::tlab_used(Thread* thr) const { 993 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 994 if (_young_gen->supports_tlab_allocation()) { 995 return _young_gen->tlab_used(); 996 } 997 return 0; 998 } 999 1000 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1001 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1002 if (_young_gen->supports_tlab_allocation()) { 1003 return _young_gen->unsafe_max_tlab_alloc(); 1004 } 1005 return 0; 1006 } 1007 1008 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { 1009 bool gc_overhead_limit_was_exceeded; 1010 return gen_policy()->mem_allocate_work(size /* size */, 1011 true /* is_tlab */, 1012 &gc_overhead_limit_was_exceeded); 1013 } 1014 1015 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1016 // from the list headed by "*prev_ptr". 1017 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1018 bool first = true; 1019 size_t min_size = 0; // "first" makes this conceptually infinite. 1020 ScratchBlock **smallest_ptr, *smallest; 1021 ScratchBlock *cur = *prev_ptr; 1022 while (cur) { 1023 assert(*prev_ptr == cur, "just checking"); 1024 if (first || cur->num_words < min_size) { 1025 smallest_ptr = prev_ptr; 1026 smallest = cur; 1027 min_size = smallest->num_words; 1028 first = false; 1029 } 1030 prev_ptr = &cur->next; 1031 cur = cur->next; 1032 } 1033 smallest = *smallest_ptr; 1034 *smallest_ptr = smallest->next; 1035 return smallest; 1036 } 1037 1038 // Sort the scratch block list headed by res into decreasing size order, 1039 // and set "res" to the result. 1040 static void sort_scratch_list(ScratchBlock*& list) { 1041 ScratchBlock* sorted = NULL; 1042 ScratchBlock* unsorted = list; 1043 while (unsorted) { 1044 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1045 smallest->next = sorted; 1046 sorted = smallest; 1047 } 1048 list = sorted; 1049 } 1050 1051 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1052 size_t max_alloc_words) { 1053 ScratchBlock* res = NULL; 1054 _young_gen->contribute_scratch(res, requestor, max_alloc_words); 1055 _old_gen->contribute_scratch(res, requestor, max_alloc_words); 1056 sort_scratch_list(res); 1057 return res; 1058 } 1059 1060 void GenCollectedHeap::release_scratch() { 1061 _young_gen->reset_scratch(); 1062 _old_gen->reset_scratch(); 1063 } 1064 1065 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1066 void do_generation(Generation* gen) { 1067 gen->prepare_for_verify(); 1068 } 1069 }; 1070 1071 void GenCollectedHeap::prepare_for_verify() { 1072 ensure_parsability(false); // no need to retire TLABs 1073 GenPrepareForVerifyClosure blk; 1074 generation_iterate(&blk, false); 1075 } 1076 1077 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1078 bool old_to_young) { 1079 if (old_to_young) { 1080 cl->do_generation(_old_gen); 1081 cl->do_generation(_young_gen); 1082 } else { 1083 cl->do_generation(_young_gen); 1084 cl->do_generation(_old_gen); 1085 } 1086 } 1087 1088 bool GenCollectedHeap::is_maximal_no_gc() const { 1089 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); 1090 } 1091 1092 void GenCollectedHeap::save_marks() { 1093 _young_gen->save_marks(); 1094 _old_gen->save_marks(); 1095 } 1096 1097 GenCollectedHeap* GenCollectedHeap::heap() { 1098 CollectedHeap* heap = Universe::heap(); 1099 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1100 assert(heap->kind() == CollectedHeap::GenCollectedHeap, "Not a GenCollectedHeap"); 1101 return (GenCollectedHeap*)heap; 1102 } 1103 1104 void GenCollectedHeap::prepare_for_compaction() { 1105 // Start by compacting into same gen. 1106 CompactPoint cp(_old_gen); 1107 _old_gen->prepare_for_compaction(&cp); 1108 _young_gen->prepare_for_compaction(&cp); 1109 } 1110 1111 void GenCollectedHeap::verify(VerifyOption option /* ignored */) { 1112 log_debug(gc, verify)("%s", _old_gen->name()); 1113 _old_gen->verify(); 1114 1115 log_debug(gc, verify)("%s", _old_gen->name()); 1116 _young_gen->verify(); 1117 1118 log_debug(gc, verify)("RemSet"); 1119 rem_set()->verify(); 1120 } 1121 1122 void GenCollectedHeap::print_on(outputStream* st) const { 1123 _young_gen->print_on(st); 1124 _old_gen->print_on(st); 1125 MetaspaceAux::print_on(st); 1126 } 1127 1128 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1129 if (workers() != NULL) { 1130 workers()->threads_do(tc); 1131 } 1132 #if INCLUDE_ALL_GCS 1133 if (UseConcMarkSweepGC) { 1134 ConcurrentMarkSweepThread::threads_do(tc); 1135 } 1136 #endif // INCLUDE_ALL_GCS 1137 } 1138 1139 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1140 #if INCLUDE_ALL_GCS 1141 if (UseConcMarkSweepGC) { 1142 workers()->print_worker_threads_on(st); 1143 ConcurrentMarkSweepThread::print_all_on(st); 1144 } 1145 #endif // INCLUDE_ALL_GCS 1146 } 1147 1148 void GenCollectedHeap::print_on_error(outputStream* st) const { 1149 this->CollectedHeap::print_on_error(st); 1150 1151 #if INCLUDE_ALL_GCS 1152 if (UseConcMarkSweepGC) { 1153 st->cr(); 1154 CMSCollector::print_on_error(st); 1155 } 1156 #endif // INCLUDE_ALL_GCS 1157 } 1158 1159 void GenCollectedHeap::print_tracing_info() const { 1160 if (TraceYoungGenTime) { 1161 _young_gen->print_summary_info(); 1162 } 1163 if (TraceOldGenTime) { 1164 _old_gen->print_summary_info(); 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 }