1 /* 2 * Copyright (c) 2000, 2019, 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/metaspaceCounters.hpp" 59 #include "memory/resourceArea.hpp" 60 #include "memory/universe.hpp" 61 #include "oops/oop.inline.hpp" 62 #include "runtime/biasedLocking.hpp" 63 #include "runtime/flags/flagSetting.hpp" 64 #include "runtime/handles.hpp" 65 #include "runtime/handles.inline.hpp" 66 #include "runtime/java.hpp" 67 #include "runtime/vmThread.hpp" 68 #include "services/management.hpp" 69 #include "services/memoryService.hpp" 70 #include "utilities/debug.hpp" 71 #include "utilities/formatBuffer.hpp" 72 #include "utilities/macros.hpp" 73 #include "utilities/stack.inline.hpp" 74 #include "utilities/vmError.hpp" 75 #if INCLUDE_JVMCI 76 #include "jvmci/jvmci.hpp" 77 #endif 78 79 GenCollectedHeap::GenCollectedHeap(Generation::Name young, 80 Generation::Name old, 81 const char* policy_counters_name) : 82 CollectedHeap(), 83 _young_gen_spec(new GenerationSpec(young, 84 NewSize, 85 MaxNewSize, 86 GenAlignment)), 87 _old_gen_spec(new GenerationSpec(old, 88 OldSize, 89 MaxOldSize, 90 GenAlignment)), 91 _rem_set(NULL), 92 _soft_ref_gen_policy(), 93 _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)), 94 _full_collections_completed(0), 95 _process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)) { 96 } 97 98 jint GenCollectedHeap::initialize() { 99 // While there are no constraints in the GC code that HeapWordSize 100 // be any particular value, there are multiple other areas in the 101 // system which believe this to be true (e.g. oop->object_size in some 102 // cases incorrectly returns the size in wordSize units rather than 103 // HeapWordSize). 104 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); 105 106 // Allocate space for the heap. 107 108 ReservedHeapSpace heap_rs = allocate(HeapAlignment); 109 110 if (!heap_rs.is_reserved()) { 111 vm_shutdown_during_initialization( 112 "Could not reserve enough space for object heap"); 113 return JNI_ENOMEM; 114 } 115 116 initialize_reserved_region(heap_rs); 117 118 _rem_set = create_rem_set(heap_rs.region()); 119 _rem_set->initialize(); 120 CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set); 121 bs->initialize(); 122 BarrierSet::set_barrier_set(bs); 123 124 ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size(), false, false); 125 _young_gen = _young_gen_spec->init(young_rs, rem_set()); 126 ReservedSpace old_rs = heap_rs.last_part(_young_gen_spec->max_size()); 127 128 old_rs = old_rs.first_part(_old_gen_spec->max_size(), false, false); 129 _old_gen = _old_gen_spec->init(old_rs, rem_set()); 130 clear_incremental_collection_failed(); 131 132 return JNI_OK; 133 } 134 135 CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) { 136 return new CardTableRS(reserved_region, false /* scan_concurrently */); 137 } 138 139 void GenCollectedHeap::initialize_size_policy(size_t init_eden_size, 140 size_t init_promo_size, 141 size_t init_survivor_size) { 142 const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0; 143 _size_policy = new AdaptiveSizePolicy(init_eden_size, 144 init_promo_size, 145 init_survivor_size, 146 max_gc_pause_sec, 147 GCTimeRatio); 148 } 149 150 ReservedHeapSpace GenCollectedHeap::allocate(size_t alignment) { 151 // Now figure out the total size. 152 const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size(); 153 assert(alignment % pageSize == 0, "Must be"); 154 155 // Check for overflow. 156 size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size(); 157 if (total_reserved < _young_gen_spec->max_size()) { 158 vm_exit_during_initialization("The size of the object heap + VM data exceeds " 159 "the maximum representable size"); 160 } 161 assert(total_reserved % alignment == 0, 162 "Gen size; total_reserved=" SIZE_FORMAT ", alignment=" 163 SIZE_FORMAT, total_reserved, alignment); 164 165 ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment); 166 167 os::trace_page_sizes("Heap", 168 MinHeapSize, 169 total_reserved, 170 alignment, 171 heap_rs.base(), 172 heap_rs.size()); 173 174 return heap_rs; 175 } 176 177 class GenIsScavengable : public BoolObjectClosure { 178 public: 179 bool do_object_b(oop obj) { 180 return GenCollectedHeap::heap()->is_in_young(obj); 181 } 182 }; 183 184 static GenIsScavengable _is_scavengable; 185 186 void GenCollectedHeap::post_initialize() { 187 CollectedHeap::post_initialize(); 188 ref_processing_init(); 189 190 DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; 191 192 initialize_size_policy(def_new_gen->eden()->capacity(), 193 _old_gen->capacity(), 194 def_new_gen->from()->capacity()); 195 196 MarkSweep::initialize(); 197 198 ScavengableNMethods::initialize(&_is_scavengable); 199 } 200 201 void GenCollectedHeap::ref_processing_init() { 202 _young_gen->ref_processor_init(); 203 _old_gen->ref_processor_init(); 204 } 205 206 PreGenGCValues GenCollectedHeap::get_pre_gc_values() const { 207 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen(); 208 209 return PreGenGCValues(def_new_gen->used(), 210 def_new_gen->capacity(), 211 def_new_gen->eden()->used(), 212 def_new_gen->eden()->capacity(), 213 def_new_gen->from()->used(), 214 def_new_gen->from()->capacity(), 215 old_gen()->used(), 216 old_gen()->capacity()); 217 } 218 219 GenerationSpec* GenCollectedHeap::young_gen_spec() const { 220 return _young_gen_spec; 221 } 222 223 GenerationSpec* GenCollectedHeap::old_gen_spec() const { 224 return _old_gen_spec; 225 } 226 227 size_t GenCollectedHeap::capacity() const { 228 return _young_gen->capacity() + _old_gen->capacity(); 229 } 230 231 size_t GenCollectedHeap::used() const { 232 return _young_gen->used() + _old_gen->used(); 233 } 234 235 void GenCollectedHeap::save_used_regions() { 236 _old_gen->save_used_region(); 237 _young_gen->save_used_region(); 238 } 239 240 size_t GenCollectedHeap::max_capacity() const { 241 return _young_gen->max_capacity() + _old_gen->max_capacity(); 242 } 243 244 // Update the _full_collections_completed counter 245 // at the end of a stop-world full GC. 246 unsigned int GenCollectedHeap::update_full_collections_completed() { 247 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 248 assert(_full_collections_completed <= _total_full_collections, 249 "Can't complete more collections than were started"); 250 _full_collections_completed = _total_full_collections; 251 ml.notify_all(); 252 return _full_collections_completed; 253 } 254 255 // Update the _full_collections_completed counter, as appropriate, 256 // at the end of a concurrent GC cycle. Note the conditional update 257 // below to allow this method to be called by a concurrent collector 258 // without synchronizing in any manner with the VM thread (which 259 // may already have initiated a STW full collection "concurrently"). 260 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 261 MonitorLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 262 assert((_full_collections_completed <= _total_full_collections) && 263 (count <= _total_full_collections), 264 "Can't complete more collections than were started"); 265 if (count > _full_collections_completed) { 266 _full_collections_completed = count; 267 ml.notify_all(); 268 } 269 return _full_collections_completed; 270 } 271 272 // Return true if any of the following is true: 273 // . the allocation won't fit into the current young gen heap 274 // . gc locker is occupied (jni critical section) 275 // . heap memory is tight -- the most recent previous collection 276 // was a full collection because a partial collection (would 277 // have) failed and is likely to fail again 278 bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const { 279 size_t young_capacity = _young_gen->capacity_before_gc(); 280 return (word_size > heap_word_size(young_capacity)) 281 || GCLocker::is_active_and_needs_gc() 282 || incremental_collection_failed(); 283 } 284 285 HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) { 286 HeapWord* result = NULL; 287 if (_old_gen->should_allocate(size, is_tlab)) { 288 result = _old_gen->expand_and_allocate(size, is_tlab); 289 } 290 if (result == NULL) { 291 if (_young_gen->should_allocate(size, is_tlab)) { 292 result = _young_gen->expand_and_allocate(size, is_tlab); 293 } 294 } 295 assert(result == NULL || is_in_reserved(result), "result not in heap"); 296 return result; 297 } 298 299 HeapWord* GenCollectedHeap::mem_allocate_work(size_t size, 300 bool is_tlab, 301 bool* gc_overhead_limit_was_exceeded) { 302 // In general gc_overhead_limit_was_exceeded should be false so 303 // set it so here and reset it to true only if the gc time 304 // limit is being exceeded as checked below. 305 *gc_overhead_limit_was_exceeded = false; 306 307 HeapWord* result = NULL; 308 309 // Loop until the allocation is satisfied, or unsatisfied after GC. 310 for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) { 311 HandleMark hm; // Discard any handles allocated in each iteration. 312 313 // First allocation attempt is lock-free. 314 Generation *young = _young_gen; 315 assert(young->supports_inline_contig_alloc(), 316 "Otherwise, must do alloc within heap lock"); 317 if (young->should_allocate(size, is_tlab)) { 318 result = young->par_allocate(size, is_tlab); 319 if (result != NULL) { 320 assert(is_in_reserved(result), "result not in heap"); 321 return result; 322 } 323 } 324 uint gc_count_before; // Read inside the Heap_lock locked region. 325 { 326 MutexLocker ml(Heap_lock); 327 log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation"); 328 // Note that only large objects get a shot at being 329 // allocated in later generations. 330 bool first_only = !should_try_older_generation_allocation(size); 331 332 result = attempt_allocation(size, is_tlab, first_only); 333 if (result != NULL) { 334 assert(is_in_reserved(result), "result not in heap"); 335 return result; 336 } 337 338 if (GCLocker::is_active_and_needs_gc()) { 339 if (is_tlab) { 340 return NULL; // Caller will retry allocating individual object. 341 } 342 if (!is_maximal_no_gc()) { 343 // Try and expand heap to satisfy request. 344 result = expand_heap_and_allocate(size, is_tlab); 345 // Result could be null if we are out of space. 346 if (result != NULL) { 347 return result; 348 } 349 } 350 351 if (gclocker_stalled_count > GCLockerRetryAllocationCount) { 352 return NULL; // We didn't get to do a GC and we didn't get any memory. 353 } 354 355 // If this thread is not in a jni critical section, we stall 356 // the requestor until the critical section has cleared and 357 // GC allowed. When the critical section clears, a GC is 358 // initiated by the last thread exiting the critical section; so 359 // we retry the allocation sequence from the beginning of the loop, 360 // rather than causing more, now probably unnecessary, GC attempts. 361 JavaThread* jthr = JavaThread::current(); 362 if (!jthr->in_critical()) { 363 MutexUnlocker mul(Heap_lock); 364 // Wait for JNI critical section to be exited 365 GCLocker::stall_until_clear(); 366 gclocker_stalled_count += 1; 367 continue; 368 } else { 369 if (CheckJNICalls) { 370 fatal("Possible deadlock due to allocating while" 371 " in jni critical section"); 372 } 373 return NULL; 374 } 375 } 376 377 // Read the gc count while the heap lock is held. 378 gc_count_before = total_collections(); 379 } 380 381 VM_GenCollectForAllocation op(size, is_tlab, gc_count_before); 382 VMThread::execute(&op); 383 if (op.prologue_succeeded()) { 384 result = op.result(); 385 if (op.gc_locked()) { 386 assert(result == NULL, "must be NULL if gc_locked() is true"); 387 continue; // Retry and/or stall as necessary. 388 } 389 390 // Allocation has failed and a collection 391 // has been done. If the gc time limit was exceeded the 392 // this time, return NULL so that an out-of-memory 393 // will be thrown. Clear gc_overhead_limit_exceeded 394 // so that the overhead exceeded does not persist. 395 396 const bool limit_exceeded = size_policy()->gc_overhead_limit_exceeded(); 397 const bool softrefs_clear = soft_ref_policy()->all_soft_refs_clear(); 398 399 if (limit_exceeded && softrefs_clear) { 400 *gc_overhead_limit_was_exceeded = true; 401 size_policy()->set_gc_overhead_limit_exceeded(false); 402 if (op.result() != NULL) { 403 CollectedHeap::fill_with_object(op.result(), size); 404 } 405 return NULL; 406 } 407 assert(result == NULL || is_in_reserved(result), 408 "result not in heap"); 409 return result; 410 } 411 412 // Give a warning if we seem to be looping forever. 413 if ((QueuedAllocationWarningCount > 0) && 414 (try_count % QueuedAllocationWarningCount == 0)) { 415 log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times," 416 " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : ""); 417 } 418 } 419 } 420 421 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 422 bool is_tlab, 423 bool first_only) { 424 HeapWord* res = NULL; 425 426 if (_young_gen->should_allocate(size, is_tlab)) { 427 res = _young_gen->allocate(size, is_tlab); 428 if (res != NULL || first_only) { 429 return res; 430 } 431 } 432 433 if (_old_gen->should_allocate(size, is_tlab)) { 434 res = _old_gen->allocate(size, is_tlab); 435 } 436 437 return res; 438 } 439 440 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 441 bool* gc_overhead_limit_was_exceeded) { 442 return mem_allocate_work(size, 443 false /* is_tlab */, 444 gc_overhead_limit_was_exceeded); 445 } 446 447 bool GenCollectedHeap::must_clear_all_soft_refs() { 448 return _gc_cause == GCCause::_metadata_GC_clear_soft_refs || 449 _gc_cause == GCCause::_wb_full_gc; 450 } 451 452 void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, 453 bool is_tlab, bool run_verification, bool clear_soft_refs, 454 bool restore_marks_for_biased_locking) { 455 FormatBuffer<> title("Collect gen: %s", gen->short_name()); 456 GCTraceTime(Trace, gc, phases) t1(title); 457 TraceCollectorStats tcs(gen->counters()); 458 TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause()); 459 460 gen->stat_record()->invocations++; 461 gen->stat_record()->accumulated_time.start(); 462 463 // Must be done anew before each collection because 464 // a previous collection will do mangling and will 465 // change top of some spaces. 466 record_gen_tops_before_GC(); 467 468 log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize); 469 470 if (run_verification && VerifyBeforeGC) { 471 HandleMark hm; // Discard invalid handles created during verification 472 Universe::verify("Before GC"); 473 } 474 COMPILER2_PRESENT(DerivedPointerTable::clear()); 475 476 if (restore_marks_for_biased_locking) { 477 // We perform this mark word preservation work lazily 478 // because it's only at this point that we know whether we 479 // absolutely have to do it; we want to avoid doing it for 480 // scavenge-only collections where it's unnecessary 481 BiasedLocking::preserve_marks(); 482 } 483 484 // Do collection work 485 { 486 // Note on ref discovery: For what appear to be historical reasons, 487 // GCH enables and disabled (by enqueing) refs discovery. 488 // In the future this should be moved into the generation's 489 // collect method so that ref discovery and enqueueing concerns 490 // are local to a generation. The collect method could return 491 // an appropriate indication in the case that notification on 492 // the ref lock was needed. This will make the treatment of 493 // weak refs more uniform (and indeed remove such concerns 494 // from GCH). XXX 495 496 HandleMark hm; // Discard invalid handles created during gc 497 save_marks(); // save marks for all gens 498 // We want to discover references, but not process them yet. 499 // This mode is disabled in process_discovered_references if the 500 // generation does some collection work, or in 501 // enqueue_discovered_references if the generation returns 502 // without doing any work. 503 ReferenceProcessor* rp = gen->ref_processor(); 504 // If the discovery of ("weak") refs in this generation is 505 // atomic wrt other collectors in this configuration, we 506 // are guaranteed to have empty discovered ref lists. 507 if (rp->discovery_is_atomic()) { 508 rp->enable_discovery(); 509 rp->setup_policy(clear_soft_refs); 510 } else { 511 // collect() below will enable discovery as appropriate 512 } 513 gen->collect(full, clear_soft_refs, size, is_tlab); 514 if (!rp->enqueuing_is_done()) { 515 rp->disable_discovery(); 516 } else { 517 rp->set_enqueuing_is_done(false); 518 } 519 rp->verify_no_references_recorded(); 520 } 521 522 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 523 524 gen->stat_record()->accumulated_time.stop(); 525 526 update_gc_stats(gen, full); 527 528 if (run_verification && VerifyAfterGC) { 529 HandleMark hm; // Discard invalid handles created during verification 530 Universe::verify("After GC"); 531 } 532 } 533 534 void GenCollectedHeap::do_collection(bool full, 535 bool clear_all_soft_refs, 536 size_t size, 537 bool is_tlab, 538 GenerationType max_generation) { 539 ResourceMark rm; 540 DEBUG_ONLY(Thread* my_thread = Thread::current();) 541 542 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 543 assert(my_thread->is_VM_thread() || 544 my_thread->is_ConcurrentGC_thread(), 545 "incorrect thread type capability"); 546 assert(Heap_lock->is_locked(), 547 "the requesting thread should have the Heap_lock"); 548 guarantee(!is_gc_active(), "collection is not reentrant"); 549 550 if (GCLocker::check_active_before_gc()) { 551 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 552 } 553 554 const bool do_clear_all_soft_refs = clear_all_soft_refs || 555 soft_ref_policy()->should_clear_all_soft_refs(); 556 557 ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy()); 558 559 FlagSetting fl(_is_gc_active, true); 560 561 bool complete = full && (max_generation == OldGen); 562 bool old_collects_young = complete && !ScavengeBeforeFullGC; 563 bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab); 564 565 const PreGenGCValues pre_gc_values = get_pre_gc_values(); 566 567 bool run_verification = total_collections() >= VerifyGCStartAt; 568 bool prepared_for_verification = false; 569 bool do_full_collection = false; 570 571 if (do_young_collection) { 572 GCIdMark gc_id_mark; 573 GCTraceCPUTime tcpu; 574 GCTraceTime(Info, gc) t("Pause Young", NULL, gc_cause(), true); 575 576 print_heap_before_gc(); 577 578 if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { 579 prepare_for_verify(); 580 prepared_for_verification = true; 581 } 582 583 gc_prologue(complete); 584 increment_total_collections(complete); 585 586 collect_generation(_young_gen, 587 full, 588 size, 589 is_tlab, 590 run_verification && VerifyGCLevel <= 0, 591 do_clear_all_soft_refs, 592 false); 593 594 if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && 595 size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { 596 // Allocation request was met by young GC. 597 size = 0; 598 } 599 600 // Ask if young collection is enough. If so, do the final steps for young collection, 601 // and fallthrough to the end. 602 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation); 603 if (!do_full_collection) { 604 // Adjust generation sizes. 605 _young_gen->compute_new_size(); 606 607 print_heap_change(pre_gc_values); 608 609 // Track memory usage and detect low memory after GC finishes 610 MemoryService::track_memory_usage(); 611 612 gc_epilogue(complete); 613 } 614 615 print_heap_after_gc(); 616 617 } else { 618 // No young collection, ask if we need to perform Full collection. 619 do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation); 620 } 621 622 if (do_full_collection) { 623 GCIdMark gc_id_mark; 624 GCTraceCPUTime tcpu; 625 GCTraceTime(Info, gc) t("Pause Full", NULL, gc_cause(), true); 626 627 print_heap_before_gc(); 628 629 if (!prepared_for_verification && run_verification && 630 VerifyGCLevel <= 1 && VerifyBeforeGC) { 631 prepare_for_verify(); 632 } 633 634 if (!do_young_collection) { 635 gc_prologue(complete); 636 increment_total_collections(complete); 637 } 638 639 // Accounting quirk: total full collections would be incremented when "complete" 640 // is set, by calling increment_total_collections above. However, we also need to 641 // account Full collections that had "complete" unset. 642 if (!complete) { 643 increment_total_full_collections(); 644 } 645 646 collect_generation(_old_gen, 647 full, 648 size, 649 is_tlab, 650 run_verification && VerifyGCLevel <= 1, 651 do_clear_all_soft_refs, 652 true); 653 654 // Adjust generation sizes. 655 _old_gen->compute_new_size(); 656 _young_gen->compute_new_size(); 657 658 // Delete metaspaces for unloaded class loaders and clean up loader_data graph 659 ClassLoaderDataGraph::purge(); 660 MetaspaceUtils::verify_metrics(); 661 // Resize the metaspace capacity after full collections 662 MetaspaceGC::compute_new_size(); 663 update_full_collections_completed(); 664 665 print_heap_change(pre_gc_values); 666 667 // Track memory usage and detect low memory after GC finishes 668 MemoryService::track_memory_usage(); 669 670 // Need to tell the epilogue code we are done with Full GC, regardless what was 671 // the initial value for "complete" flag. 672 gc_epilogue(true); 673 674 BiasedLocking::restore_marks(); 675 676 print_heap_after_gc(); 677 } 678 679 #ifdef TRACESPINNING 680 ParallelTaskTerminator::print_termination_counts(); 681 #endif 682 } 683 684 bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab, 685 GenCollectedHeap::GenerationType max_gen) const { 686 return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab); 687 } 688 689 void GenCollectedHeap::register_nmethod(nmethod* nm) { 690 ScavengableNMethods::register_nmethod(nm); 691 } 692 693 void GenCollectedHeap::unregister_nmethod(nmethod* nm) { 694 ScavengableNMethods::unregister_nmethod(nm); 695 } 696 697 void GenCollectedHeap::verify_nmethod(nmethod* nm) { 698 ScavengableNMethods::verify_nmethod(nm); 699 } 700 701 void GenCollectedHeap::flush_nmethod(nmethod* nm) { 702 // Do nothing. 703 } 704 705 void GenCollectedHeap::prune_scavengable_nmethods() { 706 ScavengableNMethods::prune_nmethods(); 707 } 708 709 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 710 GCCauseSetter x(this, GCCause::_allocation_failure); 711 HeapWord* result = NULL; 712 713 assert(size != 0, "Precondition violated"); 714 if (GCLocker::is_active_and_needs_gc()) { 715 // GC locker is active; instead of a collection we will attempt 716 // to expand the heap, if there's room for expansion. 717 if (!is_maximal_no_gc()) { 718 result = expand_heap_and_allocate(size, is_tlab); 719 } 720 return result; // Could be null if we are out of space. 721 } else if (!incremental_collection_will_fail(false /* don't consult_young */)) { 722 // Do an incremental collection. 723 do_collection(false, // full 724 false, // clear_all_soft_refs 725 size, // size 726 is_tlab, // is_tlab 727 GenCollectedHeap::OldGen); // max_generation 728 } else { 729 log_trace(gc)(" :: Trying full because partial may fail :: "); 730 // Try a full collection; see delta for bug id 6266275 731 // for the original code and why this has been simplified 732 // with from-space allocation criteria modified and 733 // such allocation moved out of the safepoint path. 734 do_collection(true, // full 735 false, // clear_all_soft_refs 736 size, // size 737 is_tlab, // is_tlab 738 GenCollectedHeap::OldGen); // max_generation 739 } 740 741 result = attempt_allocation(size, is_tlab, false /*first_only*/); 742 743 if (result != NULL) { 744 assert(is_in_reserved(result), "result not in heap"); 745 return result; 746 } 747 748 // OK, collection failed, try expansion. 749 result = expand_heap_and_allocate(size, is_tlab); 750 if (result != NULL) { 751 return result; 752 } 753 754 // If we reach this point, we're really out of memory. Try every trick 755 // we can to reclaim memory. Force collection of soft references. Force 756 // a complete compaction of the heap. Any additional methods for finding 757 // free memory should be here, especially if they are expensive. If this 758 // attempt fails, an OOM exception will be thrown. 759 { 760 UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted 761 762 do_collection(true, // full 763 true, // clear_all_soft_refs 764 size, // size 765 is_tlab, // is_tlab 766 GenCollectedHeap::OldGen); // max_generation 767 } 768 769 result = attempt_allocation(size, is_tlab, false /* first_only */); 770 if (result != NULL) { 771 assert(is_in_reserved(result), "result not in heap"); 772 return result; 773 } 774 775 assert(!soft_ref_policy()->should_clear_all_soft_refs(), 776 "Flag should have been handled and cleared prior to this point"); 777 778 // What else? We might try synchronous finalization later. If the total 779 // space available is large enough for the allocation, then a more 780 // complete compaction phase than we've tried so far might be 781 // appropriate. 782 return NULL; 783 } 784 785 #ifdef ASSERT 786 class AssertNonScavengableClosure: public OopClosure { 787 public: 788 virtual void do_oop(oop* p) { 789 assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), 790 "Referent should not be scavengable."); } 791 virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } 792 }; 793 static AssertNonScavengableClosure assert_is_non_scavengable_closure; 794 #endif 795 796 void GenCollectedHeap::process_roots(StrongRootsScope* scope, 797 ScanningOption so, 798 OopClosure* strong_roots, 799 CLDClosure* strong_cld_closure, 800 CLDClosure* weak_cld_closure, 801 CodeBlobToOopClosure* code_roots) { 802 // General roots. 803 assert(code_roots != NULL, "code root closure should always be set"); 804 // _n_termination for _process_strong_tasks should be set up stream 805 // in a method not running in a GC worker. Otherwise the GC worker 806 // could be trying to change the termination condition while the task 807 // is executing in another GC worker. 808 809 if (_process_strong_tasks->try_claim_task(GCH_PS_ClassLoaderDataGraph_oops_do)) { 810 ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); 811 } 812 813 // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway 814 CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots; 815 816 bool is_par = scope->n_threads() > 1; 817 Threads::possibly_parallel_oops_do(is_par, strong_roots, roots_from_code_p); 818 819 if (_process_strong_tasks->try_claim_task(GCH_PS_Universe_oops_do)) { 820 Universe::oops_do(strong_roots); 821 } 822 // Global (strong) JNI handles 823 if (_process_strong_tasks->try_claim_task(GCH_PS_JNIHandles_oops_do)) { 824 JNIHandles::oops_do(strong_roots); 825 } 826 827 if (_process_strong_tasks->try_claim_task(GCH_PS_ObjectSynchronizer_oops_do)) { 828 ObjectSynchronizer::oops_do(strong_roots); 829 } 830 if (_process_strong_tasks->try_claim_task(GCH_PS_Management_oops_do)) { 831 Management::oops_do(strong_roots); 832 } 833 if (_process_strong_tasks->try_claim_task(GCH_PS_jvmti_oops_do)) { 834 JvmtiExport::oops_do(strong_roots); 835 } 836 #if INCLUDE_AOT 837 if (UseAOT && _process_strong_tasks->try_claim_task(GCH_PS_aot_oops_do)) { 838 AOTLoader::oops_do(strong_roots); 839 } 840 #endif 841 if (_process_strong_tasks->try_claim_task(GCH_PS_SystemDictionary_oops_do)) { 842 SystemDictionary::oops_do(strong_roots); 843 } 844 845 if (_process_strong_tasks->try_claim_task(GCH_PS_CodeCache_oops_do)) { 846 if (so & SO_ScavengeCodeCache) { 847 assert(code_roots != NULL, "must supply closure for code cache"); 848 849 // We only visit parts of the CodeCache when scavenging. 850 ScavengableNMethods::nmethods_do(code_roots); 851 } 852 if (so & SO_AllCodeCache) { 853 assert(code_roots != NULL, "must supply closure for code cache"); 854 855 // CMSCollector uses this to do intermediate-strength collections. 856 // We scan the entire code cache, since CodeCache::do_unloading is not called. 857 CodeCache::blobs_do(code_roots); 858 } 859 // Verify that the code cache contents are not subject to 860 // movement by a scavenging collection. 861 DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); 862 DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); 863 } 864 } 865 866 void GenCollectedHeap::young_process_roots(StrongRootsScope* scope, 867 OopsInGenClosure* root_closure, 868 OopsInGenClosure* old_gen_closure, 869 CLDClosure* cld_closure) { 870 MarkingCodeBlobClosure mark_code_closure(root_closure, CodeBlobToOopClosure::FixRelocations); 871 872 process_roots(scope, SO_ScavengeCodeCache, root_closure, 873 cld_closure, cld_closure, &mark_code_closure); 874 875 if (_process_strong_tasks->try_claim_task(GCH_PS_younger_gens)) { 876 root_closure->reset_generation(); 877 } 878 879 // When collection is parallel, all threads get to cooperate to do 880 // old generation scanning. 881 old_gen_closure->set_generation(_old_gen); 882 rem_set()->younger_refs_iterate(_old_gen, old_gen_closure, scope->n_threads()); 883 old_gen_closure->reset_generation(); 884 885 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 886 } 887 888 void GenCollectedHeap::full_process_roots(StrongRootsScope* scope, 889 bool is_adjust_phase, 890 ScanningOption so, 891 bool only_strong_roots, 892 OopsInGenClosure* root_closure, 893 CLDClosure* cld_closure) { 894 MarkingCodeBlobClosure mark_code_closure(root_closure, is_adjust_phase); 895 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 896 897 process_roots(scope, so, root_closure, cld_closure, weak_cld_closure, &mark_code_closure); 898 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 899 } 900 901 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { 902 WeakProcessor::oops_do(root_closure); 903 _young_gen->ref_processor()->weak_oops_do(root_closure); 904 _old_gen->ref_processor()->weak_oops_do(root_closure); 905 } 906 907 bool GenCollectedHeap::no_allocs_since_save_marks() { 908 return _young_gen->no_allocs_since_save_marks() && 909 _old_gen->no_allocs_since_save_marks(); 910 } 911 912 bool GenCollectedHeap::supports_inline_contig_alloc() const { 913 return _young_gen->supports_inline_contig_alloc(); 914 } 915 916 HeapWord* volatile* GenCollectedHeap::top_addr() const { 917 return _young_gen->top_addr(); 918 } 919 920 HeapWord** GenCollectedHeap::end_addr() const { 921 return _young_gen->end_addr(); 922 } 923 924 // public collection interfaces 925 926 void GenCollectedHeap::collect(GCCause::Cause cause) { 927 if ((cause == GCCause::_wb_young_gc) || 928 (cause == GCCause::_gc_locker)) { 929 // Young collection for WhiteBox or GCLocker. 930 collect(cause, YoungGen); 931 } else { 932 #ifdef ASSERT 933 if (cause == GCCause::_scavenge_alot) { 934 // Young collection only. 935 collect(cause, YoungGen); 936 } else { 937 // Stop-the-world full collection. 938 collect(cause, OldGen); 939 } 940 #else 941 // Stop-the-world full collection. 942 collect(cause, OldGen); 943 #endif 944 } 945 } 946 947 void GenCollectedHeap::collect(GCCause::Cause cause, GenerationType max_generation) { 948 // The caller doesn't have the Heap_lock 949 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 950 MutexLocker ml(Heap_lock); 951 collect_locked(cause, max_generation); 952 } 953 954 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 955 // The caller has the Heap_lock 956 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 957 collect_locked(cause, OldGen); 958 } 959 960 // this is the private collection interface 961 // The Heap_lock is expected to be held on entry. 962 963 void GenCollectedHeap::collect_locked(GCCause::Cause cause, GenerationType max_generation) { 964 // Read the GC count while holding the Heap_lock 965 unsigned int gc_count_before = total_collections(); 966 unsigned int full_gc_count_before = total_full_collections(); 967 968 if (GCLocker::should_discard(cause, gc_count_before)) { 969 return; 970 } 971 972 { 973 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 974 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 975 cause, max_generation); 976 VMThread::execute(&op); 977 } 978 } 979 980 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { 981 do_full_collection(clear_all_soft_refs, OldGen); 982 } 983 984 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 985 GenerationType last_generation) { 986 do_collection(true, // full 987 clear_all_soft_refs, // clear_all_soft_refs 988 0, // size 989 false, // is_tlab 990 last_generation); // last_generation 991 // Hack XXX FIX ME !!! 992 // A scavenge may not have been attempted, or may have 993 // been attempted and failed, because the old gen was too full 994 if (gc_cause() == GCCause::_gc_locker && incremental_collection_failed()) { 995 log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed"); 996 // This time allow the old gen to be collected as well 997 do_collection(true, // full 998 clear_all_soft_refs, // clear_all_soft_refs 999 0, // size 1000 false, // is_tlab 1001 OldGen); // last_generation 1002 } 1003 } 1004 1005 bool GenCollectedHeap::is_in_young(oop p) { 1006 bool result = ((HeapWord*)p) < _old_gen->reserved().start(); 1007 assert(result == _young_gen->is_in_reserved(p), 1008 "incorrect test - result=%d, p=" INTPTR_FORMAT, result, p2i((void*)p)); 1009 return result; 1010 } 1011 1012 // Returns "TRUE" iff "p" points into the committed areas of the heap. 1013 bool GenCollectedHeap::is_in(const void* p) const { 1014 return _young_gen->is_in(p) || _old_gen->is_in(p); 1015 } 1016 1017 #ifdef ASSERT 1018 // Don't implement this by using is_in_young(). This method is used 1019 // in some cases to check that is_in_young() is correct. 1020 bool GenCollectedHeap::is_in_partial_collection(const void* p) { 1021 assert(is_in_reserved(p) || p == NULL, 1022 "Does not work if address is non-null and outside of the heap"); 1023 return p < _young_gen->reserved().end() && p != NULL; 1024 } 1025 #endif 1026 1027 void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) { 1028 _young_gen->oop_iterate(cl); 1029 _old_gen->oop_iterate(cl); 1030 } 1031 1032 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 1033 _young_gen->object_iterate(cl); 1034 _old_gen->object_iterate(cl); 1035 } 1036 1037 Space* GenCollectedHeap::space_containing(const void* addr) const { 1038 Space* res = _young_gen->space_containing(addr); 1039 if (res != NULL) { 1040 return res; 1041 } 1042 res = _old_gen->space_containing(addr); 1043 assert(res != NULL, "Could not find containing space"); 1044 return res; 1045 } 1046 1047 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 1048 assert(is_in_reserved(addr), "block_start of address outside of heap"); 1049 if (_young_gen->is_in_reserved(addr)) { 1050 assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); 1051 return _young_gen->block_start(addr); 1052 } 1053 1054 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 1055 assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); 1056 return _old_gen->block_start(addr); 1057 } 1058 1059 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 1060 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 1061 assert(block_start(addr) == addr, "addr must be a block start"); 1062 if (_young_gen->is_in_reserved(addr)) { 1063 return _young_gen->block_is_obj(addr); 1064 } 1065 1066 assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); 1067 return _old_gen->block_is_obj(addr); 1068 } 1069 1070 bool GenCollectedHeap::supports_tlab_allocation() const { 1071 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1072 return _young_gen->supports_tlab_allocation(); 1073 } 1074 1075 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 1076 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1077 if (_young_gen->supports_tlab_allocation()) { 1078 return _young_gen->tlab_capacity(); 1079 } 1080 return 0; 1081 } 1082 1083 size_t GenCollectedHeap::tlab_used(Thread* thr) const { 1084 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1085 if (_young_gen->supports_tlab_allocation()) { 1086 return _young_gen->tlab_used(); 1087 } 1088 return 0; 1089 } 1090 1091 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1092 assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); 1093 if (_young_gen->supports_tlab_allocation()) { 1094 return _young_gen->unsafe_max_tlab_alloc(); 1095 } 1096 return 0; 1097 } 1098 1099 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size, 1100 size_t requested_size, 1101 size_t* actual_size) { 1102 bool gc_overhead_limit_was_exceeded; 1103 HeapWord* result = mem_allocate_work(requested_size /* size */, 1104 true /* is_tlab */, 1105 &gc_overhead_limit_was_exceeded); 1106 if (result != NULL) { 1107 *actual_size = requested_size; 1108 } 1109 1110 return result; 1111 } 1112 1113 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1114 // from the list headed by "*prev_ptr". 1115 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1116 bool first = true; 1117 size_t min_size = 0; // "first" makes this conceptually infinite. 1118 ScratchBlock **smallest_ptr, *smallest; 1119 ScratchBlock *cur = *prev_ptr; 1120 while (cur) { 1121 assert(*prev_ptr == cur, "just checking"); 1122 if (first || cur->num_words < min_size) { 1123 smallest_ptr = prev_ptr; 1124 smallest = cur; 1125 min_size = smallest->num_words; 1126 first = false; 1127 } 1128 prev_ptr = &cur->next; 1129 cur = cur->next; 1130 } 1131 smallest = *smallest_ptr; 1132 *smallest_ptr = smallest->next; 1133 return smallest; 1134 } 1135 1136 // Sort the scratch block list headed by res into decreasing size order, 1137 // and set "res" to the result. 1138 static void sort_scratch_list(ScratchBlock*& list) { 1139 ScratchBlock* sorted = NULL; 1140 ScratchBlock* unsorted = list; 1141 while (unsorted) { 1142 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1143 smallest->next = sorted; 1144 sorted = smallest; 1145 } 1146 list = sorted; 1147 } 1148 1149 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1150 size_t max_alloc_words) { 1151 ScratchBlock* res = NULL; 1152 _young_gen->contribute_scratch(res, requestor, max_alloc_words); 1153 _old_gen->contribute_scratch(res, requestor, max_alloc_words); 1154 sort_scratch_list(res); 1155 return res; 1156 } 1157 1158 void GenCollectedHeap::release_scratch() { 1159 _young_gen->reset_scratch(); 1160 _old_gen->reset_scratch(); 1161 } 1162 1163 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1164 void do_generation(Generation* gen) { 1165 gen->prepare_for_verify(); 1166 } 1167 }; 1168 1169 void GenCollectedHeap::prepare_for_verify() { 1170 ensure_parsability(false); // no need to retire TLABs 1171 GenPrepareForVerifyClosure blk; 1172 generation_iterate(&blk, false); 1173 } 1174 1175 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1176 bool old_to_young) { 1177 if (old_to_young) { 1178 cl->do_generation(_old_gen); 1179 cl->do_generation(_young_gen); 1180 } else { 1181 cl->do_generation(_young_gen); 1182 cl->do_generation(_old_gen); 1183 } 1184 } 1185 1186 bool GenCollectedHeap::is_maximal_no_gc() const { 1187 return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); 1188 } 1189 1190 void GenCollectedHeap::save_marks() { 1191 _young_gen->save_marks(); 1192 _old_gen->save_marks(); 1193 } 1194 1195 GenCollectedHeap* GenCollectedHeap::heap() { 1196 CollectedHeap* heap = Universe::heap(); 1197 assert(heap != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1198 assert(heap->kind() == CollectedHeap::Serial, "Invalid name"); 1199 return (GenCollectedHeap*) heap; 1200 } 1201 1202 #if INCLUDE_SERIALGC 1203 void GenCollectedHeap::prepare_for_compaction() { 1204 // Start by compacting into same gen. 1205 CompactPoint cp(_old_gen); 1206 _old_gen->prepare_for_compaction(&cp); 1207 _young_gen->prepare_for_compaction(&cp); 1208 } 1209 #endif // INCLUDE_SERIALGC 1210 1211 void GenCollectedHeap::verify(VerifyOption option /* ignored */) { 1212 log_debug(gc, verify)("%s", _old_gen->name()); 1213 _old_gen->verify(); 1214 1215 log_debug(gc, verify)("%s", _old_gen->name()); 1216 _young_gen->verify(); 1217 1218 log_debug(gc, verify)("RemSet"); 1219 rem_set()->verify(); 1220 } 1221 1222 void GenCollectedHeap::print_on(outputStream* st) const { 1223 _young_gen->print_on(st); 1224 _old_gen->print_on(st); 1225 MetaspaceUtils::print_on(st); 1226 } 1227 1228 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1229 } 1230 1231 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1232 } 1233 1234 bool GenCollectedHeap::print_location(outputStream* st, void* addr) const { 1235 return BlockLocationPrinter<GenCollectedHeap>::print_location(st, addr); 1236 } 1237 1238 void GenCollectedHeap::print_tracing_info() const { 1239 if (log_is_enabled(Debug, gc, heap, exit)) { 1240 LogStreamHandle(Debug, gc, heap, exit) lsh; 1241 _young_gen->print_summary_info_on(&lsh); 1242 _old_gen->print_summary_info_on(&lsh); 1243 } 1244 } 1245 1246 void GenCollectedHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const { 1247 const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen(); 1248 1249 log_info(gc, heap)(HEAP_CHANGE_FORMAT" " 1250 HEAP_CHANGE_FORMAT" " 1251 HEAP_CHANGE_FORMAT, 1252 HEAP_CHANGE_FORMAT_ARGS(def_new_gen->short_name(), 1253 pre_gc_values.young_gen_used(), 1254 pre_gc_values.young_gen_capacity(), 1255 def_new_gen->used(), 1256 def_new_gen->capacity()), 1257 HEAP_CHANGE_FORMAT_ARGS("Eden", 1258 pre_gc_values.eden_used(), 1259 pre_gc_values.eden_capacity(), 1260 def_new_gen->eden()->used(), 1261 def_new_gen->eden()->capacity()), 1262 HEAP_CHANGE_FORMAT_ARGS("From", 1263 pre_gc_values.from_used(), 1264 pre_gc_values.from_capacity(), 1265 def_new_gen->from()->used(), 1266 def_new_gen->from()->capacity())); 1267 log_info(gc, heap)(HEAP_CHANGE_FORMAT, 1268 HEAP_CHANGE_FORMAT_ARGS(old_gen()->short_name(), 1269 pre_gc_values.old_gen_used(), 1270 pre_gc_values.old_gen_capacity(), 1271 old_gen()->used(), 1272 old_gen()->capacity())); 1273 MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes()); 1274 } 1275 1276 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1277 private: 1278 bool _full; 1279 public: 1280 void do_generation(Generation* gen) { 1281 gen->gc_prologue(_full); 1282 } 1283 GenGCPrologueClosure(bool full) : _full(full) {}; 1284 }; 1285 1286 void GenCollectedHeap::gc_prologue(bool full) { 1287 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1288 1289 // Fill TLAB's and such 1290 ensure_parsability(true); // retire TLABs 1291 1292 // Walk generations 1293 GenGCPrologueClosure blk(full); 1294 generation_iterate(&blk, false); // not old-to-young. 1295 }; 1296 1297 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1298 private: 1299 bool _full; 1300 public: 1301 void do_generation(Generation* gen) { 1302 gen->gc_epilogue(_full); 1303 } 1304 GenGCEpilogueClosure(bool full) : _full(full) {}; 1305 }; 1306 1307 void GenCollectedHeap::gc_epilogue(bool full) { 1308 #if COMPILER2_OR_JVMCI 1309 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1310 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1311 guarantee(is_client_compilation_mode_vm() || actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1312 #endif // COMPILER2_OR_JVMCI 1313 1314 resize_all_tlabs(); 1315 1316 GenGCEpilogueClosure blk(full); 1317 generation_iterate(&blk, false); // not old-to-young. 1318 1319 if (!CleanChunkPoolAsync) { 1320 Chunk::clean_chunk_pool(); 1321 } 1322 1323 MetaspaceCounters::update_performance_counters(); 1324 CompressedClassSpaceCounters::update_performance_counters(); 1325 }; 1326 1327 #ifndef PRODUCT 1328 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1329 private: 1330 public: 1331 void do_generation(Generation* gen) { 1332 gen->record_spaces_top(); 1333 } 1334 }; 1335 1336 void GenCollectedHeap::record_gen_tops_before_GC() { 1337 if (ZapUnusedHeapArea) { 1338 GenGCSaveTopsBeforeGCClosure blk; 1339 generation_iterate(&blk, false); // not old-to-young. 1340 } 1341 } 1342 #endif // not PRODUCT 1343 1344 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1345 public: 1346 void do_generation(Generation* gen) { 1347 gen->ensure_parsability(); 1348 } 1349 }; 1350 1351 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1352 CollectedHeap::ensure_parsability(retire_tlabs); 1353 GenEnsureParsabilityClosure ep_cl; 1354 generation_iterate(&ep_cl, false); 1355 } 1356 1357 oop GenCollectedHeap::handle_failed_promotion(Generation* old_gen, 1358 oop obj, 1359 size_t obj_size) { 1360 guarantee(old_gen == _old_gen, "We only get here with an old generation"); 1361 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1362 HeapWord* result = NULL; 1363 1364 result = old_gen->expand_and_allocate(obj_size, false); 1365 1366 if (result != NULL) { 1367 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 1368 } 1369 return oop(result); 1370 } 1371 1372 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1373 jlong _time; // in ms 1374 jlong _now; // in ms 1375 1376 public: 1377 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1378 1379 jlong time() { return _time; } 1380 1381 void do_generation(Generation* gen) { 1382 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1383 } 1384 }; 1385 1386 jlong GenCollectedHeap::millis_since_last_gc() { 1387 // javaTimeNanos() is guaranteed to be monotonically non-decreasing 1388 // provided the underlying platform provides such a time source 1389 // (and it is bug free). So we still have to guard against getting 1390 // back a time later than 'now'. 1391 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 1392 GenTimeOfLastGCClosure tolgc_cl(now); 1393 // iterate over generations getting the oldest 1394 // time that a generation was collected 1395 generation_iterate(&tolgc_cl, false); 1396 1397 jlong retVal = now - tolgc_cl.time(); 1398 if (retVal < 0) { 1399 log_warning(gc)("millis_since_last_gc() would return : " JLONG_FORMAT 1400 ". returning zero instead.", retVal); 1401 return 0; 1402 } 1403 return retVal; 1404 }