1 /* 2 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "aot/aotLoader.hpp" 27 #include "classfile/classLoaderDataGraph.hpp" 28 #include "classfile/symbolTable.hpp" 29 #include "classfile/stringTable.hpp" 30 #include "classfile/systemDictionary.hpp" 31 #include "classfile/vmSymbols.hpp" 32 #include "code/codeCache.hpp" 33 #include "code/icBuffer.hpp" 34 #include "gc/serial/defNewGeneration.hpp" 35 #include "gc/shared/adaptiveSizePolicy.hpp" 36 #include "gc/shared/cardTableBarrierSet.hpp" 37 #include "gc/shared/cardTableRS.hpp" 38 #include "gc/shared/collectedHeap.inline.hpp" 39 #include "gc/shared/collectorCounters.hpp" 40 #include "gc/shared/gcId.hpp" 41 #include "gc/shared/gcLocker.hpp" 42 #include "gc/shared/gcPolicyCounters.hpp" 43 #include "gc/shared/gcTrace.hpp" 44 #include "gc/shared/gcTraceTime.inline.hpp" 45 #include "gc/shared/genArguments.hpp" 46 #include "gc/shared/gcVMOperations.hpp" 47 #include "gc/shared/genCollectedHeap.hpp" 48 #include "gc/shared/genOopClosures.inline.hpp" 49 #include "gc/shared/generationSpec.hpp" 50 #include "gc/shared/locationPrinter.inline.hpp" 51 #include "gc/shared/oopStorageParState.inline.hpp" 52 #include "gc/shared/scavengableNMethods.hpp" 53 #include "gc/shared/space.hpp" 54 #include "gc/shared/strongRootsScope.hpp" 55 #include "gc/shared/weakProcessor.hpp" 56 #include "gc/shared/workgroup.hpp" 57 #include "memory/filemap.hpp" 58 #include "memory/iterator.hpp" 59 #include "memory/metaspaceCounters.hpp" 60 #include "memory/resourceArea.hpp" 61 #include "memory/universe.hpp" 62 #include "oops/oop.inline.hpp" 63 #include "runtime/biasedLocking.hpp" 64 #include "runtime/flags/flagSetting.hpp" 65 #include "runtime/handles.hpp" 66 #include "runtime/handles.inline.hpp" 67 #include "runtime/java.hpp" 68 #include "runtime/vmThread.hpp" 69 #include "services/management.hpp" 70 #include "services/memoryService.hpp" 71 #include "utilities/debug.hpp" 72 #include "utilities/formatBuffer.hpp" 73 #include "utilities/macros.hpp" 74 #include "utilities/stack.inline.hpp" 75 #include "utilities/vmError.hpp" 76 #if INCLUDE_JVMCI 77 #include "jvmci/jvmci.hpp" 78 #endif 79 80 GenCollectedHeap::GenCollectedHeap(Generation::Name young, 81 Generation::Name old, 82 const char* policy_counters_name) : 83 CollectedHeap(), 84 _young_gen_spec(new GenerationSpec(young, 85 NewSize, 86 MaxNewSize, 87 GenAlignment)), 88 _old_gen_spec(new GenerationSpec(old, 89 OldSize, 90 MaxOldSize, 91 GenAlignment)), 92 _rem_set(NULL), 93 _soft_ref_gen_policy(), 94 _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)), 95 _full_collections_completed(0), 96 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)) { 97 } 98 99 jint GenCollectedHeap::initialize() { 100 // While there are no constraints in the GC code that HeapWordSize 101 // be any particular value, there are multiple other areas in the 102 // system which believe this to be true (e.g. oop->object_size in some 103 // cases incorrectly returns the size in wordSize units rather than 104 // HeapWordSize). 105 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); 106 107 // Allocate space for the heap. 108 109 ReservedHeapSpace heap_rs = allocate(HeapAlignment); 110 111 if (!heap_rs.is_reserved()) { 112 vm_shutdown_during_initialization( 113 "Could not reserve enough space for object heap"); 114 return JNI_ENOMEM; 115 } 116 117 initialize_reserved_region(heap_rs); 118 119 _rem_set = create_rem_set(heap_rs.region()); 120 _rem_set->initialize(); 121 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set); 122 bs->initialize(); 123 BarrierSet::set_barrier_set(bs); 124 125 ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size(), false, false); 126 _young_gen = _young_gen_spec->init(young_rs, rem_set()); 127 ReservedSpace old_rs = heap_rs.last_part(_young_gen_spec->max_size()); 128 129 old_rs = old_rs.first_part(_old_gen_spec->max_size(), false, false); 130 _old_gen = _old_gen_spec->init(old_rs, rem_set()); 131 clear_incremental_collection_failed(); 132 133 return JNI_OK; 134 } 135 136 CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) { 137 return new CardTableRS(reserved_region, false /* scan_concurrently */); 138 } 139 140 void GenCollectedHeap::initialize_size_policy(size_t init_eden_size, 141 size_t init_promo_size, 142 size_t init_survivor_size) { 143 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0; 144 _size_policy = new AdaptiveSizePolicy(init_eden_size, 145 init_promo_size, 146 init_survivor_size, 147 max_gc_pause_sec, 148 GCTimeRatio); 149 } 150 151 ReservedHeapSpace GenCollectedHeap::allocate(size_t alignment) { 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 // Check for overflow. 157 size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size(); 158 if (total_reserved < _young_gen_spec->max_size()) { 159 vm_exit_during_initialization("The size of the object heap + VM data exceeds " 160 "the maximum representable size"); 161 } 162 assert(total_reserved % alignment == 0, 163 "Gen size; total_reserved=" SIZE_FORMAT ", alignment=" 164 SIZE_FORMAT, total_reserved, alignment); 165 166 ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment); 167 168 os::trace_page_sizes("Heap", 169 MinHeapSize, 170 total_reserved, 171 alignment, 172 heap_rs.base(), 173 heap_rs.size()); 174 175 return heap_rs; 176 } 177 178 class GenIsScavengable : public BoolObjectClosure { 179 public: 180 bool do_object_b(oop obj) { 181 return GenCollectedHeap::heap()->is_in_young(obj); 182 } 183 }; 184 185 static GenIsScavengable _is_scavengable; 186 187 void GenCollectedHeap::post_initialize() { 188 CollectedHeap::post_initialize(); 189 ref_processing_init(); 190 191 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; 192 193 initialize_size_policy(def_new_gen->eden()->capacity(), 194 _old_gen->capacity(), 195 def_new_gen->from()->capacity()); 196 197 MarkSweep::initialize(); 198 199 ScavengableNMethods::initialize(&_is_scavengable); 200 } 201 202 void GenCollectedHeap::ref_processing_init() { 203 _young_gen->ref_processor_init(); 204 _old_gen->ref_processor_init(); 205 } 206 207 PreGenGCValues GenCollectedHeap::get_pre_gc_values() const { 208 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen(); 209 210 return PreGenGCValues(def_new_gen->used(), 211 def_new_gen->capacity(), 212 def_new_gen->eden()->used(), 213 def_new_gen->eden()->capacity(), 214 def_new_gen->from()->used(), 215 def_new_gen->from()->capacity(), 216 old_gen()->used(), 217 old_gen()->capacity()); 218 } 219 220 GenerationSpec* GenCollectedHeap::young_gen_spec() const { 221 return _young_gen_spec; 222 } 223 224 GenerationSpec* GenCollectedHeap::old_gen_spec() const { 225 return _old_gen_spec; 226 } 227 228 size_t GenCollectedHeap::capacity() const { 229 return _young_gen->capacity() + _old_gen->capacity(); 230 } 231 232 size_t GenCollectedHeap::used() const { 233 return _young_gen->used() + _old_gen->used(); 234 } 235 236 void GenCollectedHeap::save_used_regions() { 237 _old_gen->save_used_region(); 238 _young_gen->save_used_region(); 239 } 240 241 size_t GenCollectedHeap::max_capacity() const { 242 return _young_gen->max_capacity() + _old_gen->max_capacity(); 243 } 244 245 // Update the _full_collections_completed counter 246 // at the end of a stop-world full GC. 247 unsigned int GenCollectedHeap::update_full_collections_completed() { 248 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 249 assert(_full_collections_completed <= _total_full_collections, 250 "Can't complete more collections than were started"); 251 _full_collections_completed = _total_full_collections; 252 ml.notify_all(); 253 return _full_collections_completed; 254 } 255 256 // Update the _full_collections_completed counter, as appropriate, 257 // at the end of a concurrent GC cycle. Note the conditional update 258 // below to allow this method to be called by a concurrent collector 259 // without synchronizing in any manner with the VM thread (which 260 // may already have initiated a STW full collection "concurrently"). 261 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 262 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 263 assert((_full_collections_completed <= _total_full_collections) && 264 (count <= _total_full_collections), 265 "Can't complete more collections than were started"); 266 if (count > _full_collections_completed) { 267 _full_collections_completed = count; 268 ml.notify_all(); 269 } 270 return _full_collections_completed; 271 } 272 273 // Return true if any of the following is true: 274 // . the allocation won't fit into the current young gen heap 275 // . gc locker is occupied (jni critical section) 276 // . heap memory is tight -- the most recent previous collection 277 // was a full collection because a partial collection (would 278 // have) failed and is likely to fail again 279 bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const { 280 size_t young_capacity = _young_gen->capacity_before_gc(); 281 return (word_size > heap_word_size(young_capacity)) 282 || GCLocker::is_active_and_needs_gc() 283 || incremental_collection_failed(); 284 } 285 286 HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) { 287 HeapWord* result = NULL; 288 if (_old_gen->should_allocate(size, is_tlab)) { 289 result = _old_gen->expand_and_allocate(size, is_tlab); 290 } 291 if (result == NULL) { 292 if (_young_gen->should_allocate(size, is_tlab)) { 293 result = _young_gen->expand_and_allocate(size, is_tlab); 294 } 295 } 296 assert(result == NULL || is_in_reserved(result), "result not in heap"); 297 return result; 298 } 299 300 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size, 301 bool is_tlab, 302 bool* gc_overhead_limit_was_exceeded) { 303 // In general gc_overhead_limit_was_exceeded should be false so 304 // set it so here and reset it to true only if the gc time 305 // limit is being exceeded as checked below. 306 *gc_overhead_limit_was_exceeded = false; 307 308 HeapWord* result = NULL; 309 310 // Loop until the allocation is satisfied, or unsatisfied after GC. 311 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) { 312 HandleMark hm; // Discard any handles allocated in each iteration. 313 314 // First allocation attempt is lock-free. 315 Generation *young = _young_gen; 316 assert(young->supports_inline_contig_alloc(), 317 "Otherwise, must do alloc within heap lock"); 318 if (young->should_allocate(size, is_tlab)) { 319 result = young->par_allocate(size, is_tlab); 320 if (result != NULL) { 321 assert(is_in_reserved(result), "result not in heap"); 322 return result; 323 } 324 } 325 uint gc_count_before; // Read inside the Heap_lock locked region. 326 { 327 MutexLocker ml(Heap_lock); 328 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation"); 329 // Note that only large objects get a shot at being 330 // allocated in later generations. 331 bool first_only = !should_try_older_generation_allocation(size); 332 333 result = attempt_allocation(size, is_tlab, first_only); 334 if (result != NULL) { 335 assert(is_in_reserved(result), "result not in heap"); 336 return result; 337 } 338 339 if (GCLocker::is_active_and_needs_gc()) { 340 if (is_tlab) { 341 return NULL; // Caller will retry allocating individual object. 342 } 343 if (!is_maximal_no_gc()) { 344 // Try and expand heap to satisfy request. 345 result = expand_heap_and_allocate(size, is_tlab); 346 // Result could be null if we are out of space. 347 if (result != NULL) { 348 return result; 349 } 350 } 351 352 if (gclocker_stalled_count > GCLockerRetryAllocationCount) { 353 return NULL; // We didn't get to do a GC and we didn't get any memory. 354 } 355 356 // If this thread is not in a jni critical section, we stall 357 // the requestor until the critical section has cleared and 358 // GC allowed. When the critical section clears, a GC is 359 // initiated by the last thread exiting the critical section; so 360 // we retry the allocation sequence from the beginning of the loop, 361 // rather than causing more, now probably unnecessary, GC attempts. 362 JavaThread* jthr = JavaThread::current(); 363 if (!jthr->in_critical()) { 364 MutexUnlocker mul(Heap_lock); 365 // Wait for JNI critical section to be exited 366 GCLocker::stall_until_clear(); 367 gclocker_stalled_count += 1; 368 continue; 369 } else { 370 if (CheckJNICalls) { 371 fatal("Possible deadlock due to allocating while" 372 " in jni critical section"); 373 } 374 return NULL; 375 } 376 } 377 378 // Read the gc count while the heap lock is held. 379 gc_count_before = total_collections(); 380 } 381 382 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before); 383 VMThread::execute(&op); 384 if (op.prologue_succeeded()) { 385 result = op.result(); 386 if (op.gc_locked()) { 387 assert(result == NULL, "must be NULL if gc_locked() is true"); 388 continue; // Retry and/or stall as necessary. 389 } 390 391 // Allocation has failed and a collection 392 // has been done. If the gc time limit was exceeded the 393 // this time, return NULL so that an out-of-memory 394 // will be thrown. Clear gc_overhead_limit_exceeded 395 // so that the overhead exceeded does not persist. 396 397 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded(); 398 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear(); 399 400 if (limit_exceeded && softrefs_clear) { 401 *gc_overhead_limit_was_exceeded = true; 402 size_policy()->set_gc_overhead_limit_exceeded(false); 403 if (op.result() != NULL) { 404 CollectedHeap::fill_with_object(op.result(), size); 405 } 406 return NULL; 407 } 408 assert(result == NULL || is_in_reserved(result), 409 "result not in heap"); 410 return result; 411 } 412 413 // Give a warning if we seem to be looping forever. 414 if ((QueuedAllocationWarningCount > 0) && 415 (try_count % QueuedAllocationWarningCount == 0)) { 416 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times," 417 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : ""); 418 } 419 } 420 } 421 422 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 423 bool is_tlab, 424 bool first_only) { 425 HeapWord* res = NULL; 426 427 if (_young_gen->should_allocate(size, is_tlab)) { 428 res = _young_gen->allocate(size, is_tlab); 429 if (res != NULL || first_only) { 430 return res; 431 } 432 } 433 434 if (_old_gen->should_allocate(size, is_tlab)) { 435 res = _old_gen->allocate(size, is_tlab); 436 } 437 438 return res; 439 } 440 441 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 442 bool* gc_overhead_limit_was_exceeded) { 443 return mem_allocate_work(size, 444 false /* is_tlab */, 445 gc_overhead_limit_was_exceeded); 446 } 447 448 bool GenCollectedHeap::must_clear_all_soft_refs() { 449 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs || 450 _gc_cause == GCCause::_wb_full_gc; 451 } 452 453 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, 454 bool is_tlab, bool run_verification, bool clear_soft_refs, 455 bool restore_marks_for_biased_locking) { 456 FormatBuffer<> title("Collect gen: %s", gen->short_name()); 457 GCTraceTime(Trace, gc, phases) t1(title); 458 TraceCollectorStats tcs(gen->counters()); 459 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause()); 460 461 gen->stat_record()->invocations++; 462 gen->stat_record()->accumulated_time.start(); 463 464 // Must be done anew before each collection because 465 // a previous collection will do mangling and will 466 // change top of some spaces. 467 record_gen_tops_before_GC(); 468 469 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize); 470 471 if (run_verification && VerifyBeforeGC) { 472 HandleMark hm; // Discard invalid handles created during verification 473 Universe::verify("Before GC"); 474 } 475 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear()); 476 477 if (restore_marks_for_biased_locking) { 478 // We perform this mark word preservation work lazily 479 // because it's only at this point that we know whether we 480 // absolutely have to do it; we want to avoid doing it for 481 // scavenge-only collections where it's unnecessary 482 BiasedLocking::preserve_marks(); 483 } 484 485 // Do collection work 486 { 487 // Note on ref discovery: For what appear to be historical reasons, 488 // GCH enables and disabled (by enqueing) refs discovery. 489 // In the future this should be moved into the generation's 490 // collect method so that ref discovery and enqueueing concerns 491 // are local to a generation. The collect method could return 492 // an appropriate indication in the case that notification on 493 // the ref lock was needed. This will make the treatment of 494 // weak refs more uniform (and indeed remove such concerns 495 // from GCH). XXX 496 497 HandleMark hm; // Discard invalid handles created during gc 498 save_marks(); // save marks for all gens 499 // We want to discover references, but not process them yet. 500 // This mode is disabled in process_discovered_references if the 501 // generation does some collection work, or in 502 // enqueue_discovered_references if the generation returns 503 // without doing any work. 504 ReferenceProcessor* rp = gen->ref_processor(); 505 // If the discovery of ("weak") refs in this generation is 506 // atomic wrt other collectors in this configuration, we 507 // are guaranteed to have empty discovered ref lists. 508 if (rp->discovery_is_atomic()) { 509 rp->enable_discovery(); 510 rp->setup_policy(clear_soft_refs); 511 } else { 512 // collect() below will enable discovery as appropriate 513 } 514 gen->collect(full, clear_soft_refs, size, is_tlab); 515 if (!rp->enqueuing_is_done()) { 516 rp->disable_discovery(); 517 } else { 518 rp->set_enqueuing_is_done(false); 519 } 520 rp->verify_no_references_recorded(); 521 } 522 523 COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers()); 524 525 gen->stat_record()->accumulated_time.stop(); 526 527 update_gc_stats(gen, full); 528 529 if (run_verification && VerifyAfterGC) { 530 HandleMark hm; // Discard invalid handles created during verification 531 Universe::verify("After GC"); 532 } 533 } 534 535 void GenCollectedHeap::do_collection(bool full, 536 bool clear_all_soft_refs, 537 size_t size, 538 bool is_tlab, 539 GenerationType max_generation) { 540 ResourceMark rm; 541 DEBUG_ONLY(Thread* my_thread = Thread::current();) 542 543 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 544 assert(my_thread->is_VM_thread() || 545 my_thread->is_ConcurrentGC_thread(), 546 "incorrect thread type capability"); 547 assert(Heap_lock->is_locked(), 548 "the requesting thread should have the Heap_lock"); 549 guarantee(!is_gc_active(), "collection is not reentrant"); 550 551 if (GCLocker::check_active_before_gc()) { 552 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 553 } 554 555 const bool do_clear_all_soft_refs = clear_all_soft_refs || 556 soft_ref_policy()->should_clear_all_soft_refs(); 557 558 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy()); 559 560 FlagSetting fl(_is_gc_active, true); 561 562 bool complete = full && (max_generation == OldGen); 563 bool old_collects_young = complete && !ScavengeBeforeFullGC; 564 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab); 565 566 const PreGenGCValues pre_gc_values = get_pre_gc_values(); 567 568 bool run_verification = total_collections() >= VerifyGCStartAt; 569 bool prepared_for_verification = false; 570 bool do_full_collection = false; 571 572 if (do_young_collection) { 573 GCIdMark gc_id_mark; 574 GCTraceCPUTime tcpu; 575 GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true); 576 577 print_heap_before_gc(); 578 579 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { 580 prepare_for_verify(); 581 prepared_for_verification = true; 582 } 583 584 gc_prologue(complete); 585 increment_total_collections(complete); 586 587 collect_generation(_young_gen, 588 full, 589 size, 590 is_tlab, 591 run_verification && VerifyGCLevel <= 0, 592 do_clear_all_soft_refs, 593 false); 594 595 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && 596 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { 597 // Allocation request was met by young GC. 598 size = 0; 599 } 600 601 // Ask if young collection is enough. If so, do the final steps for young collection, 602 // and fallthrough to the end. 603 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation); 604 if (!do_full_collection) { 605 // Adjust generation sizes. 606 _young_gen->compute_new_size(); 607 608 print_heap_change(pre_gc_values); 609 610 // Track memory usage and detect low memory after GC finishes 611 MemoryService::track_memory_usage(); 612 613 gc_epilogue(complete); 614 } 615 616 print_heap_after_gc(); 617 618 } else { 619 // No young collection, ask if we need to perform Full collection. 620 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation); 621 } 622 623 if (do_full_collection) { 624 GCIdMark gc_id_mark; 625 GCTraceCPUTime tcpu; 626 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true); 627 628 print_heap_before_gc(); 629 630 if (!prepared_for_verification && run_verification && 631 VerifyGCLevel <= 1 && VerifyBeforeGC) { 632 prepare_for_verify(); 633 } 634 635 if (!do_young_collection) { 636 gc_prologue(complete); 637 increment_total_collections(complete); 638 } 639 640 // Accounting quirk: total full collections would be incremented when "complete" 641 // is set, by calling increment_total_collections above. However, we also need to 642 // account Full collections that had "complete" unset. 643 if (!complete) { 644 increment_total_full_collections(); 645 } 646 647 collect_generation(_old_gen, 648 full, 649 size, 650 is_tlab, 651 run_verification && VerifyGCLevel <= 1, 652 do_clear_all_soft_refs, 653 true); 654 655 // Adjust generation sizes. 656 _old_gen->compute_new_size(); 657 _young_gen->compute_new_size(); 658 659 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 660 ClassLoaderDataGraph::purge(); 661 MetaspaceUtils::verify_metrics(); 662 // Resize the metaspace capacity after full collections 663 MetaspaceGC::compute_new_size(); 664 update_full_collections_completed(); 665 666 print_heap_change(pre_gc_values); 667 668 // Track memory usage and detect low memory after GC finishes 669 MemoryService::track_memory_usage(); 670 671 // Need to tell the epilogue code we are done with Full GC, regardless what was 672 // the initial value for "complete" flag. 673 gc_epilogue(true); 674 675 BiasedLocking::restore_marks(); 676 677 print_heap_after_gc(); 678 } 679 } 680 681 bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab, 682 GenCollectedHeap::GenerationType max_gen) const { 683 return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab); 684 } 685 686 void GenCollectedHeap::register_nmethod(nmethod* nm) { 687 ScavengableNMethods::register_nmethod(nm); 688 } 689 690 void GenCollectedHeap::unregister_nmethod(nmethod* nm) { 691 ScavengableNMethods::unregister_nmethod(nm); 692 } 693 694 void GenCollectedHeap::verify_nmethod(nmethod* nm) { 695 ScavengableNMethods::verify_nmethod(nm); 696 } 697 698 void GenCollectedHeap::flush_nmethod(nmethod* nm) { 699 // Do nothing. 700 } 701 702 void GenCollectedHeap::prune_scavengable_nmethods() { 703 ScavengableNMethods::prune_nmethods(); 704 } 705 706 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 707 GCCauseSetter x(this, GCCause::_allocation_failure); 708 HeapWord* result = NULL; 709 710 assert(size != 0, "Precondition violated"); 711 if (GCLocker::is_active_and_needs_gc()) { 712 // GC locker is active; instead of a collection we will attempt 713 // to expand the heap, if there's room for expansion. 714 if (!is_maximal_no_gc()) { 715 result = expand_heap_and_allocate(size, is_tlab); 716 } 717 return result; // Could be null if we are out of space. 718 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) { 719 // Do an incremental collection. 720 do_collection(false, // full 721 false, // clear_all_soft_refs 722 size, // size 723 is_tlab, // is_tlab 724 GenCollectedHeap::OldGen); // max_generation 725 } else { 726 log_trace(gc)(" :: Trying full because partial may fail :: "); 727 // Try a full collection; see delta for bug id 6266275 728 // for the original code and why this has been simplified 729 // with from-space allocation criteria modified and 730 // such allocation moved out of the safepoint path. 731 do_collection(true, // full 732 false, // clear_all_soft_refs 733 size, // size 734 is_tlab, // is_tlab 735 GenCollectedHeap::OldGen); // max_generation 736 } 737 738 result = attempt_allocation(size, is_tlab, false /*first_only*/); 739 740 if (result != NULL) { 741 assert(is_in_reserved(result), "result not in heap"); 742 return result; 743 } 744 745 // OK, collection failed, try expansion. 746 result = expand_heap_and_allocate(size, is_tlab); 747 if (result != NULL) { 748 return result; 749 } 750 751 // If we reach this point, we're really out of memory. Try every trick 752 // we can to reclaim memory. Force collection of soft references. Force 753 // a complete compaction of the heap. Any additional methods for finding 754 // free memory should be here, especially if they are expensive. If this 755 // attempt fails, an OOM exception will be thrown. 756 { 757 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted 758 759 do_collection(true, // full 760 true, // clear_all_soft_refs 761 size, // size 762 is_tlab, // is_tlab 763 GenCollectedHeap::OldGen); // max_generation 764 } 765 766 result = attempt_allocation(size, is_tlab, false /* first_only */); 767 if (result != NULL) { 768 assert(is_in_reserved(result), "result not in heap"); 769 return result; 770 } 771 772 assert(!soft_ref_policy()->should_clear_all_soft_refs(), 773 "Flag should have been handled and cleared prior to this point"); 774 775 // What else? We might try synchronous finalization later. If the total 776 // space available is large enough for the allocation, then a more 777 // complete compaction phase than we've tried so far might be 778 // appropriate. 779 return NULL; 780 } 781 782 #ifdef ASSERT 783 class AssertNonScavengableClosure: public OopClosure { 784 public: 785 virtual void do_oop(oop* p) { 786 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), 787 "Referent should not be scavengable."); } 788 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 789 }; 790 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 791 #endif 792 793 void GenCollectedHeap::process_roots(StrongRootsScope* scope, 794 ScanningOption so, 795 OopClosure* strong_roots, 796 CLDClosure* strong_cld_closure, 797 CLDClosure* weak_cld_closure, 798 CodeBlobToOopClosure* code_roots) { 799 // General roots. 800 assert(code_roots != NULL, "code root closure should always be set"); 801 // _n_termination for _process_strong_tasks should be set up stream 802 // in a method not running in a GC worker. Otherwise the GC worker 803 // could be trying to change the termination condition while the task 804 // is executing in another GC worker. 805 806 if (_process_strong_tasks->try_claim_task(GCH_PS_ClassLoaderDataGraph_oops_do)) { 807 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); 808 } 809 810 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway 811 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; 812 813 bool is_par = scope->n_threads() > 1; 814 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p); 815 816 if (_process_strong_tasks->try_claim_task(GCH_PS_Universe_oops_do)) { 817 Universe::oops_do(strong_roots); 818 } 819 // Global (strong) JNI handles 820 if (_process_strong_tasks->try_claim_task(GCH_PS_JNIHandles_oops_do)) { 821 JNIHandles::oops_do(strong_roots); 822 } 823 824 if (_process_strong_tasks->try_claim_task(GCH_PS_ObjectSynchronizer_oops_do)) { 825 ObjectSynchronizer::oops_do(strong_roots); 826 } 827 if (_process_strong_tasks->try_claim_task(GCH_PS_Management_oops_do)) { 828 Management::oops_do(strong_roots); 829 } 830 if (_process_strong_tasks->try_claim_task(GCH_PS_jvmti_oops_do)) { 831 JvmtiExport::oops_do(strong_roots); 832 } 833 #if INCLUDE_AOT 834 if (UseAOT && _process_strong_tasks->try_claim_task(GCH_PS_aot_oops_do)) { 835 AOTLoader::oops_do(strong_roots); 836 } 837 #endif 838 if (_process_strong_tasks->try_claim_task(GCH_PS_SystemDictionary_oops_do)) { 839 SystemDictionary::oops_do(strong_roots); 840 } 841 842 if (_process_strong_tasks->try_claim_task(GCH_PS_CodeCache_oops_do)) { 843 if (so & SO_ScavengeCodeCache) { 844 assert(code_roots != NULL, "must supply closure for code cache"); 845 846 // We only visit parts of the CodeCache when scavenging. 847 ScavengableNMethods::nmethods_do(code_roots); 848 } 849 if (so & SO_AllCodeCache) { 850 assert(code_roots != NULL, "must supply closure for code cache"); 851 852 // CMSCollector uses this to do intermediate-strength collections. 853 // We scan the entire code cache, since CodeCache::do_unloading is not called. 854 CodeCache::blobs_do(code_roots); 855 } 856 // Verify that the code cache contents are not subject to 857 // movement by a scavenging collection. 858 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); 859 DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 860 } 861 } 862 863 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope, 864 OopsInGenClosure* root_closure, 865 OopsInGenClosure* old_gen_closure, 866 CLDClosure* cld_closure) { 867 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations); 868 869 process_roots(scope, SO_ScavengeCodeCache, root_closure, 870 cld_closure, cld_closure, &mark_code_closure); 871 872 if (_process_strong_tasks->try_claim_task(GCH_PS_younger_gens)) { 873 root_closure->reset_generation(); 874 } 875 876 // When collection is parallel, all threads get to cooperate to do 877 // old generation scanning. 878 old_gen_closure->set_generation(_old_gen); 879 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads()); 880 old_gen_closure->reset_generation(); 881 882 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 883 } 884 885 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope, 886 bool is_adjust_phase, 887 ScanningOption so, 888 bool only_strong_roots, 889 OopsInGenClosure* root_closure, 890 CLDClosure* cld_closure) { 891 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase); 892 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 893 894 process_roots(scope, so, root_closure, cld_closure, weak_cld_closure, &mark_code_closure); 895 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 896 } 897 898 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { 899 WeakProcessor::oops_do(root_closure); 900 _young_gen->ref_processor()->weak_oops_do(root_closure); 901 _old_gen->ref_processor()->weak_oops_do(root_closure); 902 } 903 904 bool GenCollectedHeap::no_allocs_since_save_marks() { 905 return _young_gen->no_allocs_since_save_marks() && 906 _old_gen->no_allocs_since_save_marks(); 907 } 908 909 bool GenCollectedHeap::supports_inline_contig_alloc() const { 910 return _young_gen->supports_inline_contig_alloc(); 911 } 912 913 HeapWord* volatile* GenCollectedHeap::top_addr() const { 914 return _young_gen->top_addr(); 915 } 916 917 HeapWord** GenCollectedHeap::end_addr() const { 918 return _young_gen->end_addr(); 919 } 920 921 // public collection interfaces 922 923 void GenCollectedHeap::collect(GCCause::Cause cause) { 924 if ((cause == GCCause::_wb_young_gc) || 925 (cause == GCCause::_gc_locker)) { 926 // Young collection for WhiteBox or GCLocker. 927 collect(cause, YoungGen); 928 } else { 929 #ifdef ASSERT 930 if (cause == GCCause::_scavenge_alot) { 931 // Young collection only. 932 collect(cause, YoungGen); 933 } else { 934 // Stop-the-world full collection. 935 collect(cause, OldGen); 936 } 937 #else 938 // Stop-the-world full collection. 939 collect(cause, OldGen); 940 #endif 941 } 942 } 943 944 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) { 945 // The caller doesn't have the Heap_lock 946 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 947 MutexLocker ml(Heap_lock); 948 collect_locked(cause, max_generation); 949 } 950 951 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 952 // The caller has the Heap_lock 953 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 954 collect_locked(cause, OldGen); 955 } 956 957 // this is the private collection interface 958 // The Heap_lock is expected to be held on entry. 959 960 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) { 961 // Read the GC count while holding the Heap_lock 962 unsigned int gc_count_before = total_collections(); 963 unsigned int full_gc_count_before = total_full_collections(); 964 965 if (GCLocker::should_discard(cause, gc_count_before)) { 966 return; 967 } 968 969 { 970 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 971 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 972 cause, max_generation); 973 VMThread::execute(&op); 974 } 975 } 976 977 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { 978 do_full_collection(clear_all_soft_refs, OldGen); 979 } 980 981 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 982 GenerationType last_generation) { 983 do_collection(true, // full 984 clear_all_soft_refs, // clear_all_soft_refs 985 0, // size 986 false, // is_tlab 987 last_generation); // last_generation 988 // Hack XXX FIX ME !!! 989 // A scavenge may not have been attempted, or may have 990 // been attempted and failed, because the old gen was too full 991 if (gc_cause() == GCCause::_gc_locker && incremental_collection_failed()) { 992 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed"); 993 // This time allow the old gen to be collected as well 994 do_collection(true, // full 995 clear_all_soft_refs, // clear_all_soft_refs 996 0, // size 997 false, // is_tlab 998 OldGen); // last_generation 999 } 1000 } 1001 1002 bool GenCollectedHeap::is_in_young(oop p) { 1003 bool result = cast_from_oop<HeapWord*>(p) < _old_gen->reserved().start(); 1004 assert(result == _young_gen->is_in_reserved(p), 1005 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)); 1006 return result; 1007 } 1008 1009 // Returns "TRUE" iff "p" points into the committed areas of the heap. 1010 bool GenCollectedHeap::is_in(const void* p) const { 1011 return _young_gen->is_in(p) || _old_gen->is_in(p); 1012 } 1013 1014 #ifdef ASSERT 1015 // Don't implement this by using is_in_young(). This method is used 1016 // in some cases to check that is_in_young() is correct. 1017 bool GenCollectedHeap::is_in_partial_collection(const void* p) { 1018 assert(is_in_reserved(p) || p == NULL, 1019 "Does not work if address is non-null and outside of the heap"); 1020 return p < _young_gen->reserved().end() && p != NULL; 1021 } 1022 #endif 1023 1024 void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) { 1025 _young_gen->oop_iterate(cl); 1026 _old_gen->oop_iterate(cl); 1027 } 1028 1029 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 1030 _young_gen->object_iterate(cl); 1031 _old_gen->object_iterate(cl); 1032 } 1033 1034 Space* GenCollectedHeap::space_containing(const void* addr) const { 1035 Space* res = _young_gen->space_containing(addr); 1036 if (res != NULL) { 1037 return res; 1038 } 1039 res = _old_gen->space_containing(addr); 1040 assert(res != NULL, "Could not find containing space"); 1041 return res; 1042 } 1043 1044 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 1045 assert(is_in_reserved(addr), "block_start of address outside of heap"); 1046 if (_young_gen->is_in_reserved(addr)) { 1047 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 1048 return _young_gen->block_start(addr); 1049 } 1050 1051 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 1052 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 1053 return _old_gen->block_start(addr); 1054 } 1055 1056 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 1057 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 1058 assert(block_start(addr) == addr, "addr must be a block start"); 1059 if (_young_gen->is_in_reserved(addr)) { 1060 return _young_gen->block_is_obj(addr); 1061 } 1062 1063 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 1064 return _old_gen->block_is_obj(addr); 1065 } 1066 1067 bool GenCollectedHeap::supports_tlab_allocation() const { 1068 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1069 return _young_gen->supports_tlab_allocation(); 1070 } 1071 1072 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 1073 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1074 if (_young_gen->supports_tlab_allocation()) { 1075 return _young_gen->tlab_capacity(); 1076 } 1077 return 0; 1078 } 1079 1080 size_t GenCollectedHeap::tlab_used(Thread* thr) const { 1081 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1082 if (_young_gen->supports_tlab_allocation()) { 1083 return _young_gen->tlab_used(); 1084 } 1085 return 0; 1086 } 1087 1088 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1089 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1090 if (_young_gen->supports_tlab_allocation()) { 1091 return _young_gen->unsafe_max_tlab_alloc(); 1092 } 1093 return 0; 1094 } 1095 1096 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size, 1097 size_t requested_size, 1098 size_t* actual_size) { 1099 bool gc_overhead_limit_was_exceeded; 1100 HeapWord* result = mem_allocate_work(requested_size /* size */, 1101 true /* is_tlab */, 1102 &gc_overhead_limit_was_exceeded); 1103 if (result != NULL) { 1104 *actual_size = requested_size; 1105 } 1106 1107 return result; 1108 } 1109 1110 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1111 // from the list headed by "*prev_ptr". 1112 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1113 bool first = true; 1114 size_t min_size = 0; // "first" makes this conceptually infinite. 1115 ScratchBlock **smallest_ptr, *smallest; 1116 ScratchBlock *cur = *prev_ptr; 1117 while (cur) { 1118 assert(*prev_ptr == cur, "just checking"); 1119 if (first || cur->num_words < min_size) { 1120 smallest_ptr = prev_ptr; 1121 smallest = cur; 1122 min_size = smallest->num_words; 1123 first = false; 1124 } 1125 prev_ptr = &cur->next; 1126 cur = cur->next; 1127 } 1128 smallest = *smallest_ptr; 1129 *smallest_ptr = smallest->next; 1130 return smallest; 1131 } 1132 1133 // Sort the scratch block list headed by res into decreasing size order, 1134 // and set "res" to the result. 1135 static void sort_scratch_list(ScratchBlock*& list) { 1136 ScratchBlock* sorted = NULL; 1137 ScratchBlock* unsorted = list; 1138 while (unsorted) { 1139 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1140 smallest->next = sorted; 1141 sorted = smallest; 1142 } 1143 list = sorted; 1144 } 1145 1146 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1147 size_t max_alloc_words) { 1148 ScratchBlock* res = NULL; 1149 _young_gen->contribute_scratch(res, requestor, max_alloc_words); 1150 _old_gen->contribute_scratch(res, requestor, max_alloc_words); 1151 sort_scratch_list(res); 1152 return res; 1153 } 1154 1155 void GenCollectedHeap::release_scratch() { 1156 _young_gen->reset_scratch(); 1157 _old_gen->reset_scratch(); 1158 } 1159 1160 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1161 void do_generation(Generation* gen) { 1162 gen->prepare_for_verify(); 1163 } 1164 }; 1165 1166 void GenCollectedHeap::prepare_for_verify() { 1167 ensure_parsability(false); // no need to retire TLABs 1168 GenPrepareForVerifyClosure blk; 1169 generation_iterate(&blk, false); 1170 } 1171 1172 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1173 bool old_to_young) { 1174 if (old_to_young) { 1175 cl->do_generation(_old_gen); 1176 cl->do_generation(_young_gen); 1177 } else { 1178 cl->do_generation(_young_gen); 1179 cl->do_generation(_old_gen); 1180 } 1181 } 1182 1183 bool GenCollectedHeap::is_maximal_no_gc() const { 1184 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); 1185 } 1186 1187 void GenCollectedHeap::save_marks() { 1188 _young_gen->save_marks(); 1189 _old_gen->save_marks(); 1190 } 1191 1192 GenCollectedHeap* GenCollectedHeap::heap() { 1193 CollectedHeap* heap = Universe::heap(); 1194 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1195 assert(heap->kind() == CollectedHeap::Serial, "Invalid name"); 1196 return (GenCollectedHeap*) heap; 1197 } 1198 1199 #if INCLUDE_SERIALGC 1200 void GenCollectedHeap::prepare_for_compaction() { 1201 // Start by compacting into same gen. 1202 CompactPoint cp(_old_gen); 1203 _old_gen->prepare_for_compaction(&cp); 1204 _young_gen->prepare_for_compaction(&cp); 1205 } 1206 #endif // INCLUDE_SERIALGC 1207 1208 void GenCollectedHeap::verify(VerifyOption option /* ignored */) { 1209 log_debug(gc, verify)("%s", _old_gen->name()); 1210 _old_gen->verify(); 1211 1212 log_debug(gc, verify)("%s", _old_gen->name()); 1213 _young_gen->verify(); 1214 1215 log_debug(gc, verify)("RemSet"); 1216 rem_set()->verify(); 1217 } 1218 1219 void GenCollectedHeap::print_on(outputStream* st) const { 1220 _young_gen->print_on(st); 1221 _old_gen->print_on(st); 1222 MetaspaceUtils::print_on(st); 1223 } 1224 1225 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1226 } 1227 1228 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1229 } 1230 1231 bool GenCollectedHeap::print_location(outputStream* st, void* addr) const { 1232 return BlockLocationPrinter<GenCollectedHeap>::print_location(st, addr); 1233 } 1234 1235 void GenCollectedHeap::print_tracing_info() const { 1236 if (log_is_enabled(Debug, gc, heap, exit)) { 1237 LogStreamHandle(Debug, gc, heap, exit) lsh; 1238 _young_gen->print_summary_info_on(&lsh); 1239 _old_gen->print_summary_info_on(&lsh); 1240 } 1241 } 1242 1243 void GenCollectedHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const { 1244 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen(); 1245 1246 log_info(gc, heap)(HEAP_CHANGE_FORMAT" " 1247 HEAP_CHANGE_FORMAT" " 1248 HEAP_CHANGE_FORMAT, 1249 HEAP_CHANGE_FORMAT_ARGS(def_new_gen->short_name(), 1250 pre_gc_values.young_gen_used(), 1251 pre_gc_values.young_gen_capacity(), 1252 def_new_gen->used(), 1253 def_new_gen->capacity()), 1254 HEAP_CHANGE_FORMAT_ARGS("Eden", 1255 pre_gc_values.eden_used(), 1256 pre_gc_values.eden_capacity(), 1257 def_new_gen->eden()->used(), 1258 def_new_gen->eden()->capacity()), 1259 HEAP_CHANGE_FORMAT_ARGS("From", 1260 pre_gc_values.from_used(), 1261 pre_gc_values.from_capacity(), 1262 def_new_gen->from()->used(), 1263 def_new_gen->from()->capacity())); 1264 log_info(gc, heap)(HEAP_CHANGE_FORMAT, 1265 HEAP_CHANGE_FORMAT_ARGS(old_gen()->short_name(), 1266 pre_gc_values.old_gen_used(), 1267 pre_gc_values.old_gen_capacity(), 1268 old_gen()->used(), 1269 old_gen()->capacity())); 1270 MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes()); 1271 } 1272 1273 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1274 private: 1275 bool _full; 1276 public: 1277 void do_generation(Generation* gen) { 1278 gen->gc_prologue(_full); 1279 } 1280 GenGCPrologueClosure(bool full) : _full(full) {}; 1281 }; 1282 1283 void GenCollectedHeap::gc_prologue(bool full) { 1284 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1285 1286 // Fill TLAB's and such 1287 ensure_parsability(true); // retire TLABs 1288 1289 // Walk generations 1290 GenGCPrologueClosure blk(full); 1291 generation_iterate(&blk, false); // not old-to-young. 1292 }; 1293 1294 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1295 private: 1296 bool _full; 1297 public: 1298 void do_generation(Generation* gen) { 1299 gen->gc_epilogue(_full); 1300 } 1301 GenGCEpilogueClosure(bool full) : _full(full) {}; 1302 }; 1303 1304 void GenCollectedHeap::gc_epilogue(bool full) { 1305 #if COMPILER2_OR_JVMCI 1306 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1307 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1308 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1309 #endif // COMPILER2_OR_JVMCI 1310 1311 resize_all_tlabs(); 1312 1313 GenGCEpilogueClosure blk(full); 1314 generation_iterate(&blk, false); // not old-to-young. 1315 1316 if (!CleanChunkPoolAsync) { 1317 Chunk::clean_chunk_pool(); 1318 } 1319 1320 MetaspaceCounters::update_performance_counters(); 1321 CompressedClassSpaceCounters::update_performance_counters(); 1322 }; 1323 1324 #ifndef PRODUCT 1325 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1326 private: 1327 public: 1328 void do_generation(Generation* gen) { 1329 gen->record_spaces_top(); 1330 } 1331 }; 1332 1333 void GenCollectedHeap::record_gen_tops_before_GC() { 1334 if (ZapUnusedHeapArea) { 1335 GenGCSaveTopsBeforeGCClosure blk; 1336 generation_iterate(&blk, false); // not old-to-young. 1337 } 1338 } 1339 #endif // not PRODUCT 1340 1341 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1342 public: 1343 void do_generation(Generation* gen) { 1344 gen->ensure_parsability(); 1345 } 1346 }; 1347 1348 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1349 CollectedHeap::ensure_parsability(retire_tlabs); 1350 GenEnsureParsabilityClosure ep_cl; 1351 generation_iterate(&ep_cl, false); 1352 } 1353 1354 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, 1355 oop obj, 1356 size_t obj_size) { 1357 guarantee(old_gen == _old_gen, "We only get here with an old generation"); 1358 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1359 HeapWord* result = NULL; 1360 1361 result = old_gen->expand_and_allocate(obj_size, false); 1362 1363 if (result != NULL) { 1364 Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(obj), result, obj_size); 1365 } 1366 return oop(result); 1367 } 1368 1369 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1370 jlong _time; // in ms 1371 jlong _now; // in ms 1372 1373 public: 1374 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1375 1376 jlong time() { return _time; } 1377 1378 void do_generation(Generation* gen) { 1379 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1380 } 1381 }; 1382 1383 jlong GenCollectedHeap::millis_since_last_gc() { 1384 // javaTimeNanos() is guaranteed to be monotonically non-decreasing 1385 // provided the underlying platform provides such a time source 1386 // (and it is bug free). So we still have to guard against getting 1387 // back a time later than 'now'. 1388 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 1389 GenTimeOfLastGCClosure tolgc_cl(now); 1390 // iterate over generations getting the oldest 1391 // time that a generation was collected 1392 generation_iterate(&tolgc_cl, false); 1393 1394 jlong retVal = now - tolgc_cl.time(); 1395 if (retVal < 0) { 1396 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT 1397 ". returning zero instead.", retVal); 1398 return 0; 1399 } 1400 return retVal; 1401 }