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