1 /* 2 * Copyright (c) 2000, 2015, 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.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 return heap_rs->base(); 171 } 172 173 void GenCollectedHeap::post_initialize() { 174 CollectedHeap::post_initialize(); 175 ref_processing_init(); 176 assert((_young_gen->kind() == Generation::DefNew) || 177 (_young_gen->kind() == Generation::ParNew), 178 "Wrong youngest generation type"); 179 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; 180 181 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep || 182 _old_gen->kind() == Generation::MarkSweepCompact, 183 "Wrong generation kind"); 184 185 _gen_policy->initialize_size_policy(def_new_gen->eden()->capacity(), 186 _old_gen->capacity(), 187 def_new_gen->from()->capacity()); 188 _gen_policy->initialize_gc_policy_counters(); 189 } 190 191 void GenCollectedHeap::ref_processing_init() { 192 _young_gen->ref_processor_init(); 193 _old_gen->ref_processor_init(); 194 } 195 196 size_t GenCollectedHeap::capacity() const { 197 return _young_gen->capacity() + _old_gen->capacity(); 198 } 199 200 size_t GenCollectedHeap::used() const { 201 return _young_gen->used() + _old_gen->used(); 202 } 203 204 void GenCollectedHeap::save_used_regions() { 205 _old_gen->save_used_region(); 206 _young_gen->save_used_region(); 207 } 208 209 size_t GenCollectedHeap::max_capacity() const { 210 return _young_gen->max_capacity() + _old_gen->max_capacity(); 211 } 212 213 // Update the _full_collections_completed counter 214 // at the end of a stop-world full GC. 215 unsigned int GenCollectedHeap::update_full_collections_completed() { 216 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 217 assert(_full_collections_completed <= _total_full_collections, 218 "Can't complete more collections than were started"); 219 _full_collections_completed = _total_full_collections; 220 ml.notify_all(); 221 return _full_collections_completed; 222 } 223 224 // Update the _full_collections_completed counter, as appropriate, 225 // at the end of a concurrent GC cycle. Note the conditional update 226 // below to allow this method to be called by a concurrent collector 227 // without synchronizing in any manner with the VM thread (which 228 // may already have initiated a STW full collection "concurrently"). 229 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 230 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 231 assert((_full_collections_completed <= _total_full_collections) && 232 (count <= _total_full_collections), 233 "Can't complete more collections than were started"); 234 if (count > _full_collections_completed) { 235 _full_collections_completed = count; 236 ml.notify_all(); 237 } 238 return _full_collections_completed; 239 } 240 241 242 #ifndef PRODUCT 243 // Override of memory state checking method in CollectedHeap: 244 // Some collectors (CMS for example) can't have badHeapWordVal written 245 // in the first two words of an object. (For instance , in the case of 246 // CMS these words hold state used to synchronize between certain 247 // (concurrent) GC steps and direct allocating mutators.) 248 // The skip_header_HeapWords() method below, allows us to skip 249 // over the requisite number of HeapWord's. Note that (for 250 // generational collectors) this means that those many words are 251 // skipped in each object, irrespective of the generation in which 252 // that object lives. The resultant loss of precision seems to be 253 // harmless and the pain of avoiding that imprecision appears somewhat 254 // higher than we are prepared to pay for such rudimentary debugging 255 // support. 256 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, 257 size_t size) { 258 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 259 // We are asked to check a size in HeapWords, 260 // but the memory is mangled in juint words. 261 juint* start = (juint*) (addr + skip_header_HeapWords()); 262 juint* end = (juint*) (addr + size); 263 for (juint* slot = start; slot < end; slot += 1) { 264 assert(*slot == badHeapWordVal, 265 "Found non badHeapWordValue in pre-allocation check"); 266 } 267 } 268 } 269 #endif 270 271 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 272 bool is_tlab, 273 bool first_only) { 274 HeapWord* res = NULL; 275 276 if (_young_gen->should_allocate(size, is_tlab)) { 277 res = _young_gen->allocate(size, is_tlab); 278 if (res != NULL || first_only) { 279 return res; 280 } 281 } 282 283 if (_old_gen->should_allocate(size, is_tlab)) { 284 res = _old_gen->allocate(size, is_tlab); 285 } 286 287 return res; 288 } 289 290 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 291 bool* gc_overhead_limit_was_exceeded) { 292 return collector_policy()->mem_allocate_work(size, 293 false /* is_tlab */, 294 gc_overhead_limit_was_exceeded); 295 } 296 297 bool GenCollectedHeap::must_clear_all_soft_refs() { 298 return _gc_cause == GCCause::_last_ditch_collection; 299 } 300 301 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { 302 if (!UseConcMarkSweepGC) { 303 return false; 304 } 305 306 switch (cause) { 307 case GCCause::_gc_locker: return GCLockerInvokesConcurrent; 308 case GCCause::_java_lang_system_gc: 309 case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent; 310 default: return false; 311 } 312 } 313 314 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, 315 bool is_tlab, bool run_verification, bool clear_soft_refs, 316 bool restore_marks_for_biased_locking) { 317 // Timer for individual generations. Last argument is false: no CR 318 // FIXME: We should try to start the timing earlier to cover more of the GC pause 319 GCTraceTime t1(gen->short_name(), PrintGCDetails, false, NULL); 320 TraceCollectorStats tcs(gen->counters()); 321 TraceMemoryManagerStats tmms(gen->kind(),gc_cause()); 322 323 size_t prev_used = gen->used(); 324 gen->stat_record()->invocations++; 325 gen->stat_record()->accumulated_time.start(); 326 327 // Must be done anew before each collection because 328 // a previous collection will do mangling and will 329 // change top of some spaces. 330 record_gen_tops_before_GC(); 331 332 if (PrintGC && Verbose) { 333 // I didn't want to change the logging when removing the level concept, 334 // but I guess this logging could say young/old or something instead of 0/1. 335 uint level; 336 if (heap()->is_young_gen(gen)) { 337 level = 0; 338 } else { 339 level = 1; 340 } 341 gclog_or_tty->print("level=%u invoke=%d size=" SIZE_FORMAT, 342 level, 343 gen->stat_record()->invocations, 344 size * HeapWordSize); 345 } 346 347 if (run_verification && VerifyBeforeGC) { 348 HandleMark hm; // Discard invalid handles created during verification 349 Universe::verify(" VerifyBeforeGC:"); 350 } 351 COMPILER2_PRESENT(DerivedPointerTable::clear()); 352 353 if (restore_marks_for_biased_locking) { 354 // We perform this mark word preservation work lazily 355 // because it's only at this point that we know whether we 356 // absolutely have to do it; we want to avoid doing it for 357 // scavenge-only collections where it's unnecessary 358 BiasedLocking::preserve_marks(); 359 } 360 361 // Do collection work 362 { 363 // Note on ref discovery: For what appear to be historical reasons, 364 // GCH enables and disabled (by enqueing) refs discovery. 365 // In the future this should be moved into the generation's 366 // collect method so that ref discovery and enqueueing concerns 367 // are local to a generation. The collect method could return 368 // an appropriate indication in the case that notification on 369 // the ref lock was needed. This will make the treatment of 370 // weak refs more uniform (and indeed remove such concerns 371 // from GCH). XXX 372 373 HandleMark hm; // Discard invalid handles created during gc 374 save_marks(); // save marks for all gens 375 // We want to discover references, but not process them yet. 376 // This mode is disabled in process_discovered_references if the 377 // generation does some collection work, or in 378 // enqueue_discovered_references if the generation returns 379 // without doing any work. 380 ReferenceProcessor* rp = gen->ref_processor(); 381 // If the discovery of ("weak") refs in this generation is 382 // atomic wrt other collectors in this configuration, we 383 // are guaranteed to have empty discovered ref lists. 384 if (rp->discovery_is_atomic()) { 385 rp->enable_discovery(); 386 rp->setup_policy(clear_soft_refs); 387 } else { 388 // collect() below will enable discovery as appropriate 389 } 390 gen->collect(full, clear_soft_refs, size, is_tlab); 391 if (!rp->enqueuing_is_done()) { 392 rp->enqueue_discovered_references(); 393 } else { 394 rp->set_enqueuing_is_done(false); 395 } 396 rp->verify_no_references_recorded(); 397 } 398 399 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 400 401 gen->stat_record()->accumulated_time.stop(); 402 403 update_gc_stats(gen, full); 404 405 if (run_verification && VerifyAfterGC) { 406 HandleMark hm; // Discard invalid handles created during verification 407 Universe::verify(" VerifyAfterGC:"); 408 } 409 410 if (PrintGCDetails) { 411 gclog_or_tty->print(":"); 412 gen->print_heap_change(prev_used); 413 } 414 } 415 416 void GenCollectedHeap::do_collection(bool full, 417 bool clear_all_soft_refs, 418 size_t size, 419 bool is_tlab, 420 GenerationType max_generation) { 421 ResourceMark rm; 422 DEBUG_ONLY(Thread* my_thread = Thread::current();) 423 424 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 425 assert(my_thread->is_VM_thread() || 426 my_thread->is_ConcurrentGC_thread(), 427 "incorrect thread type capability"); 428 assert(Heap_lock->is_locked(), 429 "the requesting thread should have the Heap_lock"); 430 guarantee(!is_gc_active(), "collection is not reentrant"); 431 432 if (GC_locker::check_active_before_gc()) { 433 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 434 } 435 436 GCIdMark gc_id_mark; 437 438 const bool do_clear_all_soft_refs = clear_all_soft_refs || 439 collector_policy()->should_clear_all_soft_refs(); 440 441 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); 442 443 const size_t metadata_prev_used = MetaspaceAux::used_bytes(); 444 445 print_heap_before_gc(); 446 447 { 448 FlagSetting fl(_is_gc_active, true); 449 450 bool complete = full && (max_generation == OldGen); 451 const char* gc_cause_prefix = complete ? "Full GC" : "GC"; 452 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); 453 GCTraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, NULL); 454 455 gc_prologue(complete); 456 increment_total_collections(complete); 457 458 size_t gch_prev_used = used(); 459 bool run_verification = total_collections() >= VerifyGCStartAt; 460 461 bool prepared_for_verification = false; 462 bool collected_old = false; 463 bool old_collects_young = complete && !ScavengeBeforeFullGC; 464 465 if (!old_collects_young && _young_gen->should_collect(full, size, is_tlab)) { 466 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { 467 prepare_for_verify(); 468 prepared_for_verification = true; 469 } 470 471 assert(!_young_gen->performs_in_place_marking(), "No young generation do in place marking"); 472 collect_generation(_young_gen, 473 full, 474 size, 475 is_tlab, 476 run_verification && VerifyGCLevel <= 0, 477 do_clear_all_soft_refs, 478 false); 479 480 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && 481 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { 482 // Allocation request was met by young GC. 483 size = 0; 484 } 485 } 486 487 bool must_restore_marks_for_biased_locking = false; 488 489 if (max_generation == OldGen && _old_gen->should_collect(full, size, is_tlab)) { 490 GCIdMark gc_id_mark; 491 if (!complete) { 492 // The full_collections increment was missed above. 493 increment_total_full_collections(); 494 } 495 496 pre_full_gc_dump(NULL); // do any pre full gc dumps 497 498 if (!prepared_for_verification && run_verification && 499 VerifyGCLevel <= 1 && VerifyBeforeGC) { 500 prepare_for_verify(); 501 } 502 503 assert(_old_gen->performs_in_place_marking(), "All old generations do in place marking"); 504 collect_generation(_old_gen, 505 full, 506 size, 507 is_tlab, 508 run_verification && VerifyGCLevel <= 1, 509 do_clear_all_soft_refs, 510 true); 511 512 must_restore_marks_for_biased_locking = true; 513 collected_old = true; 514 } 515 516 // Update "complete" boolean wrt what actually transpired -- 517 // for instance, a promotion failure could have led to 518 // a whole heap collection. 519 complete = complete || collected_old; 520 521 if (complete) { // We did a full collection 522 // FIXME: See comment at pre_full_gc_dump call 523 post_full_gc_dump(NULL); // do any post full gc dumps 524 } 525 526 if (PrintGCDetails) { 527 print_heap_change(gch_prev_used); 528 529 // Print metaspace info for full GC with PrintGCDetails flag. 530 if (complete) { 531 MetaspaceAux::print_metaspace_change(metadata_prev_used); 532 } 533 } 534 535 // Adjust generation sizes. 536 if (collected_old) { 537 _old_gen->compute_new_size(); 538 } 539 _young_gen->compute_new_size(); 540 541 if (complete) { 542 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 543 ClassLoaderDataGraph::purge(); 544 MetaspaceAux::verify_metrics(); 545 // Resize the metaspace capacity after full collections 546 MetaspaceGC::compute_new_size(); 547 update_full_collections_completed(); 548 } 549 550 // Track memory usage and detect low memory after GC finishes 551 MemoryService::track_memory_usage(); 552 553 gc_epilogue(complete); 554 555 if (must_restore_marks_for_biased_locking) { 556 BiasedLocking::restore_marks(); 557 } 558 } 559 560 print_heap_after_gc(); 561 562 #ifdef TRACESPINNING 563 ParallelTaskTerminator::print_termination_counts(); 564 #endif 565 } 566 567 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 568 return collector_policy()->satisfy_failed_allocation(size, is_tlab); 569 } 570 571 #ifdef ASSERT 572 class AssertNonScavengableClosure: public OopClosure { 573 public: 574 virtual void do_oop(oop* p) { 575 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), 576 "Referent should not be scavengable."); } 577 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 578 }; 579 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 580 #endif 581 582 void GenCollectedHeap::process_roots(StrongRootsScope* scope, 583 ScanningOption so, 584 OopClosure* strong_roots, 585 OopClosure* weak_roots, 586 CLDClosure* strong_cld_closure, 587 CLDClosure* weak_cld_closure, 588 CodeBlobClosure* code_roots) { 589 // General roots. 590 assert(Threads::thread_claim_parity() != 0, "must have called prologue code"); 591 assert(code_roots != NULL, "code root closure should always be set"); 592 // _n_termination for _process_strong_tasks should be set up stream 593 // in a method not running in a GC worker. Otherwise the GC worker 594 // could be trying to change the termination condition while the task 595 // is executing in another GC worker. 596 597 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ClassLoaderDataGraph_oops_do)) { 598 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); 599 } 600 601 // Some CLDs contained in the thread frames should be considered strong. 602 // Don't process them if they will be processed during the ClassLoaderDataGraph phase. 603 CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL; 604 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway 605 CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; 606 607 bool is_par = scope->n_threads() > 1; 608 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_clds_p, roots_from_code_p); 609 610 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Universe_oops_do)) { 611 Universe::oops_do(strong_roots); 612 } 613 // Global (strong) JNI handles 614 if (!_process_strong_tasks->is_task_claimed(GCH_PS_JNIHandles_oops_do)) { 615 JNIHandles::oops_do(strong_roots); 616 } 617 618 if (!_process_strong_tasks->is_task_claimed(GCH_PS_ObjectSynchronizer_oops_do)) { 619 ObjectSynchronizer::oops_do(strong_roots); 620 } 621 if (!_process_strong_tasks->is_task_claimed(GCH_PS_FlatProfiler_oops_do)) { 622 FlatProfiler::oops_do(strong_roots); 623 } 624 if (!_process_strong_tasks->is_task_claimed(GCH_PS_Management_oops_do)) { 625 Management::oops_do(strong_roots); 626 } 627 if (!_process_strong_tasks->is_task_claimed(GCH_PS_jvmti_oops_do)) { 628 JvmtiExport::oops_do(strong_roots); 629 } 630 631 if (!_process_strong_tasks->is_task_claimed(GCH_PS_SystemDictionary_oops_do)) { 632 SystemDictionary::roots_oops_do(strong_roots, weak_roots); 633 } 634 635 // All threads execute the following. A specific chunk of buckets 636 // from the StringTable are the individual tasks. 637 if (weak_roots != NULL) { 638 if (is_par) { 639 StringTable::possibly_parallel_oops_do(weak_roots); 640 } else { 641 StringTable::oops_do(weak_roots); 642 } 643 } 644 645 if (!_process_strong_tasks->is_task_claimed(GCH_PS_CodeCache_oops_do)) { 646 if (so & SO_ScavengeCodeCache) { 647 assert(code_roots != NULL, "must supply closure for code cache"); 648 649 // We only visit parts of the CodeCache when scavenging. 650 CodeCache::scavenge_root_nmethods_do(code_roots); 651 } 652 if (so & SO_AllCodeCache) { 653 assert(code_roots != NULL, "must supply closure for code cache"); 654 655 // CMSCollector uses this to do intermediate-strength collections. 656 // We scan the entire code cache, since CodeCache::do_unloading is not called. 657 CodeCache::blobs_do(code_roots); 658 } 659 // Verify that the code cache contents are not subject to 660 // movement by a scavenging collection. 661 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); 662 DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 663 } 664 } 665 666 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope, 667 OopsInGenClosure* root_closure, 668 OopsInGenClosure* old_gen_closure, 669 CLDClosure* cld_closure) { 670 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations); 671 672 process_roots(scope, SO_ScavengeCodeCache, root_closure, root_closure, 673 cld_closure, cld_closure, &mark_code_closure); 674 675 if (!_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 676 } 677 678 // When collection is parallel, all threads get to cooperate to do 679 // old generation scanning. 680 old_gen_closure->assert_generation(_old_gen); 681 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads()); 682 683 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 684 } 685 686 void GenCollectedHeap::old_process_roots(StrongRootsScope* scope, 687 bool young_gen_as_roots, 688 ScanningOption so, 689 bool only_strong_roots, 690 OopsInGenClosure* root_closure, 691 CLDClosure* cld_closure) { 692 const bool is_moving_collection = !only_strong_roots && !young_gen_as_roots; 693 694 MarkingCodeBlobClosure mark_code_closure(root_closure, is_moving_collection); 695 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 696 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 697 698 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 699 700 if (young_gen_as_roots && 701 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 702 root_closure->assert_generation(_young_gen); 703 _young_gen->oop_iterate(root_closure); 704 } 705 706 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 707 } 708 709 class AlwaysTrueClosure: public BoolObjectClosure { 710 public: 711 bool do_object_b(oop p) { return true; } 712 }; 713 static AlwaysTrueClosure always_true; 714 715 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { 716 JNIHandles::weak_oops_do(&always_true, root_closure); 717 _young_gen->ref_processor()->weak_oops_do(root_closure); 718 _old_gen->ref_processor()->weak_oops_do(root_closure); 719 } 720 721 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 722 void GenCollectedHeap:: \ 723 oop_since_save_marks_iterate(GenerationType gen, \ 724 OopClosureType* cur, \ 725 OopClosureType* older) { \ 726 if (gen == YoungGen) { \ 727 _young_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 728 _old_gen->oop_since_save_marks_iterate##nv_suffix(older); \ 729 } else { \ 730 _old_gen->oop_since_save_marks_iterate##nv_suffix(cur); \ 731 } \ 732 } 733 734 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) 735 736 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN 737 738 bool GenCollectedHeap::no_allocs_since_save_marks() { 739 return _young_gen->no_allocs_since_save_marks() && 740 _old_gen->no_allocs_since_save_marks(); 741 } 742 743 bool GenCollectedHeap::supports_inline_contig_alloc() const { 744 return _young_gen->supports_inline_contig_alloc(); 745 } 746 747 HeapWord** GenCollectedHeap::top_addr() const { 748 return _young_gen->top_addr(); 749 } 750 751 HeapWord** GenCollectedHeap::end_addr() const { 752 return _young_gen->end_addr(); 753 } 754 755 // public collection interfaces 756 757 void GenCollectedHeap::collect(GCCause::Cause cause) { 758 if (should_do_concurrent_full_gc(cause)) { 759 #if INCLUDE_ALL_GCS 760 // Mostly concurrent full collection. 761 collect_mostly_concurrent(cause); 762 #else // INCLUDE_ALL_GCS 763 ShouldNotReachHere(); 764 #endif // INCLUDE_ALL_GCS 765 } else if (cause == GCCause::_wb_young_gc) { 766 // Young collection for the WhiteBox API. 767 collect(cause, YoungGen); 768 } else { 769 #ifdef ASSERT 770 if (cause == GCCause::_scavenge_alot) { 771 // Young collection only. 772 collect(cause, YoungGen); 773 } else { 774 // Stop-the-world full collection. 775 collect(cause, OldGen); 776 } 777 #else 778 // Stop-the-world full collection. 779 collect(cause, OldGen); 780 #endif 781 } 782 } 783 784 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) { 785 // The caller doesn't have the Heap_lock 786 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 787 MutexLocker ml(Heap_lock); 788 collect_locked(cause, max_generation); 789 } 790 791 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 792 // The caller has the Heap_lock 793 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 794 collect_locked(cause, OldGen); 795 } 796 797 // this is the private collection interface 798 // The Heap_lock is expected to be held on entry. 799 800 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) { 801 // Read the GC count while holding the Heap_lock 802 unsigned int gc_count_before = total_collections(); 803 unsigned int full_gc_count_before = total_full_collections(); 804 { 805 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 806 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 807 cause, max_generation); 808 VMThread::execute(&op); 809 } 810 } 811 812 #if INCLUDE_ALL_GCS 813 bool GenCollectedHeap::create_cms_collector() { 814 815 assert(_old_gen->kind() == Generation::ConcurrentMarkSweep, 816 "Unexpected generation kinds"); 817 // Skip two header words in the block content verification 818 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) 819 assert(_gen_policy->is_concurrent_mark_sweep_policy(), "Unexpected policy type"); 820 CMSCollector* collector = 821 new CMSCollector((ConcurrentMarkSweepGeneration*)_old_gen, 822 _rem_set->as_CardTableRS(), 823 _gen_policy->as_concurrent_mark_sweep_policy()); 824 825 if (collector == NULL || !collector->completed_initialization()) { 826 if (collector) { 827 delete collector; // Be nice in embedded situation 828 } 829 vm_shutdown_during_initialization("Could not create CMS collector"); 830 return false; 831 } 832 return true; // success 833 } 834 835 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { 836 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 837 838 MutexLocker ml(Heap_lock); 839 // Read the GC counts while holding the Heap_lock 840 unsigned int full_gc_count_before = total_full_collections(); 841 unsigned int gc_count_before = total_collections(); 842 { 843 MutexUnlocker mu(Heap_lock); 844 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 845 VMThread::execute(&op); 846 } 847 } 848 #endif // INCLUDE_ALL_GCS 849 850 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { 851 do_full_collection(clear_all_soft_refs, OldGen); 852 } 853 854 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 855 GenerationType last_generation) { 856 GenerationType local_last_generation; 857 if (!incremental_collection_will_fail(false /* don't consult_young */) && 858 gc_cause() == GCCause::_gc_locker) { 859 local_last_generation = YoungGen; 860 } else { 861 local_last_generation = last_generation; 862 } 863 864 do_collection(true, // full 865 clear_all_soft_refs, // clear_all_soft_refs 866 0, // size 867 false, // is_tlab 868 local_last_generation); // last_generation 869 // Hack XXX FIX ME !!! 870 // A scavenge may not have been attempted, or may have 871 // been attempted and failed, because the old gen was too full 872 if (local_last_generation == YoungGen && gc_cause() == GCCause::_gc_locker && 873 incremental_collection_will_fail(false /* don't consult_young */)) { 874 if (PrintGCDetails) { 875 gclog_or_tty->print_cr("GC locker: Trying a full collection " 876 "because scavenge failed"); 877 } 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 collector_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(bool silent, VerifyOption option /* ignored */) { 1107 if (!silent) { 1108 gclog_or_tty->print("%s", _old_gen->name()); 1109 gclog_or_tty->print(" "); 1110 } 1111 _old_gen->verify(); 1112 1113 if (!silent) { 1114 gclog_or_tty->print("%s", _young_gen->name()); 1115 gclog_or_tty->print(" "); 1116 } 1117 _young_gen->verify(); 1118 1119 if (!silent) { 1120 gclog_or_tty->print("remset "); 1121 } 1122 rem_set()->verify(); 1123 } 1124 1125 void GenCollectedHeap::print_on(outputStream* st) const { 1126 _young_gen->print_on(st); 1127 _old_gen->print_on(st); 1128 MetaspaceAux::print_on(st); 1129 } 1130 1131 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1132 if (workers() != NULL) { 1133 workers()->threads_do(tc); 1134 } 1135 #if INCLUDE_ALL_GCS 1136 if (UseConcMarkSweepGC) { 1137 ConcurrentMarkSweepThread::threads_do(tc); 1138 } 1139 #endif // INCLUDE_ALL_GCS 1140 } 1141 1142 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1143 #if INCLUDE_ALL_GCS 1144 if (UseConcMarkSweepGC) { 1145 workers()->print_worker_threads_on(st); 1146 ConcurrentMarkSweepThread::print_all_on(st); 1147 } 1148 #endif // INCLUDE_ALL_GCS 1149 } 1150 1151 void GenCollectedHeap::print_on_error(outputStream* st) const { 1152 this->CollectedHeap::print_on_error(st); 1153 1154 #if INCLUDE_ALL_GCS 1155 if (UseConcMarkSweepGC) { 1156 st->cr(); 1157 CMSCollector::print_on_error(st); 1158 } 1159 #endif // INCLUDE_ALL_GCS 1160 } 1161 1162 void GenCollectedHeap::print_tracing_info() const { 1163 if (TraceYoungGenTime) { 1164 _young_gen->print_summary_info(); 1165 } 1166 if (TraceOldGenTime) { 1167 _old_gen->print_summary_info(); 1168 } 1169 } 1170 1171 void GenCollectedHeap::print_heap_change(size_t prev_used) const { 1172 if (PrintGCDetails && Verbose) { 1173 gclog_or_tty->print(" " SIZE_FORMAT 1174 "->" SIZE_FORMAT 1175 "(" SIZE_FORMAT ")", 1176 prev_used, used(), capacity()); 1177 } else { 1178 gclog_or_tty->print(" " SIZE_FORMAT "K" 1179 "->" SIZE_FORMAT "K" 1180 "(" SIZE_FORMAT "K)", 1181 prev_used / K, used() / K, capacity() / K); 1182 } 1183 } 1184 1185 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1186 private: 1187 bool _full; 1188 public: 1189 void do_generation(Generation* gen) { 1190 gen->gc_prologue(_full); 1191 } 1192 GenGCPrologueClosure(bool full) : _full(full) {}; 1193 }; 1194 1195 void GenCollectedHeap::gc_prologue(bool full) { 1196 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1197 1198 always_do_update_barrier = false; 1199 // Fill TLAB's and such 1200 CollectedHeap::accumulate_statistics_all_tlabs(); 1201 ensure_parsability(true); // retire TLABs 1202 1203 // Walk generations 1204 GenGCPrologueClosure blk(full); 1205 generation_iterate(&blk, false); // not old-to-young. 1206 }; 1207 1208 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1209 private: 1210 bool _full; 1211 public: 1212 void do_generation(Generation* gen) { 1213 gen->gc_epilogue(_full); 1214 } 1215 GenGCEpilogueClosure(bool full) : _full(full) {}; 1216 }; 1217 1218 void GenCollectedHeap::gc_epilogue(bool full) { 1219 #ifdef COMPILER2 1220 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1221 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1222 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1223 #endif /* COMPILER2 */ 1224 1225 resize_all_tlabs(); 1226 1227 GenGCEpilogueClosure blk(full); 1228 generation_iterate(&blk, false); // not old-to-young. 1229 1230 if (!CleanChunkPoolAsync) { 1231 Chunk::clean_chunk_pool(); 1232 } 1233 1234 MetaspaceCounters::update_performance_counters(); 1235 CompressedClassSpaceCounters::update_performance_counters(); 1236 1237 always_do_update_barrier = UseConcMarkSweepGC; 1238 }; 1239 1240 #ifndef PRODUCT 1241 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1242 private: 1243 public: 1244 void do_generation(Generation* gen) { 1245 gen->record_spaces_top(); 1246 } 1247 }; 1248 1249 void GenCollectedHeap::record_gen_tops_before_GC() { 1250 if (ZapUnusedHeapArea) { 1251 GenGCSaveTopsBeforeGCClosure blk; 1252 generation_iterate(&blk, false); // not old-to-young. 1253 } 1254 } 1255 #endif // not PRODUCT 1256 1257 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1258 public: 1259 void do_generation(Generation* gen) { 1260 gen->ensure_parsability(); 1261 } 1262 }; 1263 1264 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1265 CollectedHeap::ensure_parsability(retire_tlabs); 1266 GenEnsureParsabilityClosure ep_cl; 1267 generation_iterate(&ep_cl, false); 1268 } 1269 1270 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, 1271 oop obj, 1272 size_t obj_size) { 1273 guarantee(old_gen == _old_gen, "We only get here with an old generation"); 1274 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1275 HeapWord* result = NULL; 1276 1277 result = old_gen->expand_and_allocate(obj_size, false); 1278 1279 if (result != NULL) { 1280 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 1281 } 1282 return oop(result); 1283 } 1284 1285 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1286 jlong _time; // in ms 1287 jlong _now; // in ms 1288 1289 public: 1290 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1291 1292 jlong time() { return _time; } 1293 1294 void do_generation(Generation* gen) { 1295 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1296 } 1297 }; 1298 1299 jlong GenCollectedHeap::millis_since_last_gc() { 1300 // We need a monotonically non-decreasing time in ms but 1301 // os::javaTimeMillis() does not guarantee monotonicity. 1302 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 1303 GenTimeOfLastGCClosure tolgc_cl(now); 1304 // iterate over generations getting the oldest 1305 // time that a generation was collected 1306 generation_iterate(&tolgc_cl, false); 1307 1308 // javaTimeNanos() is guaranteed to be monotonically non-decreasing 1309 // provided the underlying platform provides such a time source 1310 // (and it is bug free). So we still have to guard against getting 1311 // back a time later than 'now'. 1312 jlong retVal = now - tolgc_cl.time(); 1313 if (retVal < 0) { 1314 NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, retVal);) 1315 return 0; 1316 } 1317 return retVal; 1318 }