1 /* 2 * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/symbolTable.hpp" 27 #include "classfile/systemDictionary.hpp" 28 #include "classfile/vmSymbols.hpp" 29 #include "code/icBuffer.hpp" 30 #include "gc_implementation/shared/collectorCounters.hpp" 31 #include "gc_implementation/shared/vmGCOperations.hpp" 32 #include "gc_interface/collectedHeap.inline.hpp" 33 #include "memory/compactPermGen.hpp" 34 #include "memory/filemap.hpp" 35 #include "memory/gcLocker.inline.hpp" 36 #include "memory/genCollectedHeap.hpp" 37 #include "memory/genOopClosures.inline.hpp" 38 #include "memory/generation.inline.hpp" 39 #include "memory/generationSpec.hpp" 40 #include "memory/permGen.hpp" 41 #include "memory/resourceArea.hpp" 42 #include "memory/sharedHeap.hpp" 43 #include "memory/space.hpp" 44 #include "oops/oop.inline.hpp" 45 #include "oops/oop.inline2.hpp" 46 #include "runtime/aprofiler.hpp" 47 #include "runtime/biasedLocking.hpp" 48 #include "runtime/fprofiler.hpp" 49 #include "runtime/handles.hpp" 50 #include "runtime/handles.inline.hpp" 51 #include "runtime/java.hpp" 52 #include "runtime/vmThread.hpp" 53 #include "services/memoryService.hpp" 54 #include "utilities/vmError.hpp" 55 #include "utilities/workgroup.hpp" 56 #ifndef SERIALGC 57 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 58 #include "gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp" 59 #endif 60 61 GenCollectedHeap* GenCollectedHeap::_gch; 62 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) 63 64 // The set of potentially parallel tasks in strong root scanning. 65 enum GCH_process_strong_roots_tasks { 66 // We probably want to parallelize both of these internally, but for now... 67 GCH_PS_younger_gens, 68 // Leave this one last. 69 GCH_PS_NumElements 70 }; 71 72 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) : 73 SharedHeap(policy), 74 _gen_policy(policy), 75 _gen_process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)), 76 _full_collections_completed(0) 77 { 78 if (_gen_process_strong_tasks == NULL || 79 !_gen_process_strong_tasks->valid()) { 80 vm_exit_during_initialization("Failed necessary allocation."); 81 } 82 assert(policy != NULL, "Sanity check"); 83 _preloading_shared_classes = false; 84 } 85 86 jint GenCollectedHeap::initialize() { 87 CollectedHeap::pre_initialize(); 88 89 int i; 90 _n_gens = gen_policy()->number_of_generations(); 91 92 // While there are no constraints in the GC code that HeapWordSize 93 // be any particular value, there are multiple other areas in the 94 // system which believe this to be true (e.g. oop->object_size in some 95 // cases incorrectly returns the size in wordSize units rather than 96 // HeapWordSize). 97 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); 98 99 // The heap must be at least as aligned as generations. 100 size_t alignment = Generation::GenGrain; 101 102 _gen_specs = gen_policy()->generations(); 103 PermanentGenerationSpec *perm_gen_spec = 104 collector_policy()->permanent_generation(); 105 106 // Make sure the sizes are all aligned. 107 for (i = 0; i < _n_gens; i++) { 108 _gen_specs[i]->align(alignment); 109 } 110 perm_gen_spec->align(alignment); 111 112 // If we are dumping the heap, then allocate a wasted block of address 113 // space in order to push the heap to a lower address. This extra 114 // address range allows for other (or larger) libraries to be loaded 115 // without them occupying the space required for the shared spaces. 116 117 if (DumpSharedSpaces) { 118 uintx reserved = 0; 119 uintx block_size = 64*1024*1024; 120 while (reserved < SharedDummyBlockSize) { 121 char* dummy = os::reserve_memory(block_size); 122 reserved += block_size; 123 } 124 } 125 126 // Allocate space for the heap. 127 128 char* heap_address; 129 size_t total_reserved = 0; 130 int n_covered_regions = 0; 131 ReservedSpace heap_rs(0); 132 133 heap_address = allocate(alignment, perm_gen_spec, &total_reserved, 134 &n_covered_regions, &heap_rs); 135 136 if (UseSharedSpaces) { 137 if (!heap_rs.is_reserved() || heap_address != heap_rs.base()) { 138 if (heap_rs.is_reserved()) { 139 heap_rs.release(); 140 } 141 FileMapInfo* mapinfo = FileMapInfo::current_info(); 142 mapinfo->fail_continue("Unable to reserve shared region."); 143 allocate(alignment, perm_gen_spec, &total_reserved, &n_covered_regions, 144 &heap_rs); 145 } 146 } 147 148 if (!heap_rs.is_reserved()) { 149 vm_shutdown_during_initialization( 150 "Could not reserve enough space for object heap"); 151 return JNI_ENOMEM; 152 } 153 154 _reserved = MemRegion((HeapWord*)heap_rs.base(), 155 (HeapWord*)(heap_rs.base() + heap_rs.size())); 156 157 // It is important to do this in a way such that concurrent readers can't 158 // temporarily think somethings in the heap. (Seen this happen in asserts.) 159 _reserved.set_word_size(0); 160 _reserved.set_start((HeapWord*)heap_rs.base()); 161 size_t actual_heap_size = heap_rs.size() - perm_gen_spec->misc_data_size() 162 - perm_gen_spec->misc_code_size(); 163 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size)); 164 165 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions); 166 set_barrier_set(rem_set()->bs()); 167 168 _gch = this; 169 170 for (i = 0; i < _n_gens; i++) { 171 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(), 172 UseSharedSpaces, UseSharedSpaces); 173 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set()); 174 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size()); 175 } 176 _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set()); 177 178 clear_incremental_collection_failed(); 179 180 #ifndef SERIALGC 181 // If we are running CMS, create the collector responsible 182 // for collecting the CMS generations. 183 if (collector_policy()->is_concurrent_mark_sweep_policy()) { 184 bool success = create_cms_collector(); 185 if (!success) return JNI_ENOMEM; 186 } 187 #endif // SERIALGC 188 189 return JNI_OK; 190 } 191 192 193 char* GenCollectedHeap::allocate(size_t alignment, 194 PermanentGenerationSpec* perm_gen_spec, 195 size_t* _total_reserved, 196 int* _n_covered_regions, 197 ReservedSpace* heap_rs){ 198 const char overflow_msg[] = "The size of the object heap + VM data exceeds " 199 "the maximum representable size"; 200 201 // Now figure out the total size. 202 size_t total_reserved = 0; 203 int n_covered_regions = 0; 204 const size_t pageSize = UseLargePages ? 205 os::large_page_size() : os::vm_page_size(); 206 207 for (int i = 0; i < _n_gens; i++) { 208 total_reserved += _gen_specs[i]->max_size(); 209 if (total_reserved < _gen_specs[i]->max_size()) { 210 vm_exit_during_initialization(overflow_msg); 211 } 212 n_covered_regions += _gen_specs[i]->n_covered_regions(); 213 } 214 assert(total_reserved % pageSize == 0, 215 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize=" 216 SIZE_FORMAT, total_reserved, pageSize)); 217 total_reserved += perm_gen_spec->max_size(); 218 assert(total_reserved % pageSize == 0, 219 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize=" 220 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved, 221 pageSize, perm_gen_spec->max_size())); 222 223 if (total_reserved < perm_gen_spec->max_size()) { 224 vm_exit_during_initialization(overflow_msg); 225 } 226 n_covered_regions += perm_gen_spec->n_covered_regions(); 227 228 // Add the size of the data area which shares the same reserved area 229 // as the heap, but which is not actually part of the heap. 230 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size(); 231 232 total_reserved += s; 233 if (total_reserved < s) { 234 vm_exit_during_initialization(overflow_msg); 235 } 236 237 if (UseLargePages) { 238 assert(total_reserved != 0, "total_reserved cannot be 0"); 239 total_reserved = round_to(total_reserved, os::large_page_size()); 240 if (total_reserved < os::large_page_size()) { 241 vm_exit_during_initialization(overflow_msg); 242 } 243 } 244 245 // Calculate the address at which the heap must reside in order for 246 // the shared data to be at the required address. 247 248 char* heap_address; 249 if (UseSharedSpaces) { 250 251 // Calculate the address of the first word beyond the heap. 252 FileMapInfo* mapinfo = FileMapInfo::current_info(); 253 int lr = CompactingPermGenGen::n_regions - 1; 254 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment); 255 heap_address = mapinfo->region_base(lr) + capacity; 256 257 // Calculate the address of the first word of the heap. 258 heap_address -= total_reserved; 259 } else { 260 heap_address = NULL; // any address will do. 261 if (UseCompressedOops) { 262 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop); 263 *_total_reserved = total_reserved; 264 *_n_covered_regions = n_covered_regions; 265 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 266 UseLargePages, heap_address); 267 268 if (heap_address != NULL && !heap_rs->is_reserved()) { 269 // Failed to reserve at specified address - the requested memory 270 // region is taken already, for example, by 'java' launcher. 271 // Try again to reserver heap higher. 272 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop); 273 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 274 UseLargePages, heap_address); 275 276 if (heap_address != NULL && !heap_rs->is_reserved()) { 277 // Failed to reserve at specified address again - give up. 278 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop); 279 assert(heap_address == NULL, ""); 280 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 281 UseLargePages, heap_address); 282 } 283 } 284 return heap_address; 285 } 286 } 287 288 *_total_reserved = total_reserved; 289 *_n_covered_regions = n_covered_regions; 290 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 291 UseLargePages, heap_address); 292 293 return heap_address; 294 } 295 296 297 void GenCollectedHeap::post_initialize() { 298 SharedHeap::post_initialize(); 299 TwoGenerationCollectorPolicy *policy = 300 (TwoGenerationCollectorPolicy *)collector_policy(); 301 guarantee(policy->is_two_generation_policy(), "Illegal policy type"); 302 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0); 303 assert(def_new_gen->kind() == Generation::DefNew || 304 def_new_gen->kind() == Generation::ParNew || 305 def_new_gen->kind() == Generation::ASParNew, 306 "Wrong generation kind"); 307 308 Generation* old_gen = get_gen(1); 309 assert(old_gen->kind() == Generation::ConcurrentMarkSweep || 310 old_gen->kind() == Generation::ASConcurrentMarkSweep || 311 old_gen->kind() == Generation::MarkSweepCompact, 312 "Wrong generation kind"); 313 314 policy->initialize_size_policy(def_new_gen->eden()->capacity(), 315 old_gen->capacity(), 316 def_new_gen->from()->capacity()); 317 policy->initialize_gc_policy_counters(); 318 } 319 320 void GenCollectedHeap::ref_processing_init() { 321 SharedHeap::ref_processing_init(); 322 for (int i = 0; i < _n_gens; i++) { 323 _gens[i]->ref_processor_init(); 324 } 325 } 326 327 size_t GenCollectedHeap::capacity() const { 328 size_t res = 0; 329 for (int i = 0; i < _n_gens; i++) { 330 res += _gens[i]->capacity(); 331 } 332 return res; 333 } 334 335 size_t GenCollectedHeap::used() const { 336 size_t res = 0; 337 for (int i = 0; i < _n_gens; i++) { 338 res += _gens[i]->used(); 339 } 340 return res; 341 } 342 343 // Save the "used_region" for generations level and lower, 344 // and, if perm is true, for perm gen. 345 void GenCollectedHeap::save_used_regions(int level, bool perm) { 346 assert(level < _n_gens, "Illegal level parameter"); 347 for (int i = level; i >= 0; i--) { 348 _gens[i]->save_used_region(); 349 } 350 if (perm) { 351 perm_gen()->save_used_region(); 352 } 353 } 354 355 size_t GenCollectedHeap::max_capacity() const { 356 size_t res = 0; 357 for (int i = 0; i < _n_gens; i++) { 358 res += _gens[i]->max_capacity(); 359 } 360 return res; 361 } 362 363 // Update the _full_collections_completed counter 364 // at the end of a stop-world full GC. 365 unsigned int GenCollectedHeap::update_full_collections_completed() { 366 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 367 assert(_full_collections_completed <= _total_full_collections, 368 "Can't complete more collections than were started"); 369 _full_collections_completed = _total_full_collections; 370 ml.notify_all(); 371 return _full_collections_completed; 372 } 373 374 // Update the _full_collections_completed counter, as appropriate, 375 // at the end of a concurrent GC cycle. Note the conditional update 376 // below to allow this method to be called by a concurrent collector 377 // without synchronizing in any manner with the VM thread (which 378 // may already have initiated a STW full collection "concurrently"). 379 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 380 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 381 assert((_full_collections_completed <= _total_full_collections) && 382 (count <= _total_full_collections), 383 "Can't complete more collections than were started"); 384 if (count > _full_collections_completed) { 385 _full_collections_completed = count; 386 ml.notify_all(); 387 } 388 return _full_collections_completed; 389 } 390 391 392 #ifndef PRODUCT 393 // Override of memory state checking method in CollectedHeap: 394 // Some collectors (CMS for example) can't have badHeapWordVal written 395 // in the first two words of an object. (For instance , in the case of 396 // CMS these words hold state used to synchronize between certain 397 // (concurrent) GC steps and direct allocating mutators.) 398 // The skip_header_HeapWords() method below, allows us to skip 399 // over the requisite number of HeapWord's. Note that (for 400 // generational collectors) this means that those many words are 401 // skipped in each object, irrespective of the generation in which 402 // that object lives. The resultant loss of precision seems to be 403 // harmless and the pain of avoiding that imprecision appears somewhat 404 // higher than we are prepared to pay for such rudimentary debugging 405 // support. 406 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, 407 size_t size) { 408 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 409 // We are asked to check a size in HeapWords, 410 // but the memory is mangled in juint words. 411 juint* start = (juint*) (addr + skip_header_HeapWords()); 412 juint* end = (juint*) (addr + size); 413 for (juint* slot = start; slot < end; slot += 1) { 414 assert(*slot == badHeapWordVal, 415 "Found non badHeapWordValue in pre-allocation check"); 416 } 417 } 418 } 419 #endif 420 421 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 422 bool is_tlab, 423 bool first_only) { 424 HeapWord* res; 425 for (int i = 0; i < _n_gens; i++) { 426 if (_gens[i]->should_allocate(size, is_tlab)) { 427 res = _gens[i]->allocate(size, is_tlab); 428 if (res != NULL) return res; 429 else if (first_only) break; 430 } 431 } 432 // Otherwise... 433 return NULL; 434 } 435 436 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 437 bool* gc_overhead_limit_was_exceeded) { 438 return collector_policy()->mem_allocate_work(size, 439 false /* is_tlab */, 440 gc_overhead_limit_was_exceeded); 441 } 442 443 bool GenCollectedHeap::must_clear_all_soft_refs() { 444 return _gc_cause == GCCause::_last_ditch_collection; 445 } 446 447 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { 448 return UseConcMarkSweepGC && 449 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) || 450 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)); 451 } 452 453 void GenCollectedHeap::do_collection(bool full, 454 bool clear_all_soft_refs, 455 size_t size, 456 bool is_tlab, 457 int max_level) { 458 bool prepared_for_verification = false; 459 ResourceMark rm; 460 DEBUG_ONLY(Thread* my_thread = Thread::current();) 461 462 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 463 assert(my_thread->is_VM_thread() || 464 my_thread->is_ConcurrentGC_thread(), 465 "incorrect thread type capability"); 466 assert(Heap_lock->is_locked(), 467 "the requesting thread should have the Heap_lock"); 468 guarantee(!is_gc_active(), "collection is not reentrant"); 469 assert(max_level < n_gens(), "sanity check"); 470 471 if (GC_locker::check_active_before_gc()) { 472 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 473 } 474 475 const bool do_clear_all_soft_refs = clear_all_soft_refs || 476 collector_policy()->should_clear_all_soft_refs(); 477 478 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); 479 480 const size_t perm_prev_used = perm_gen()->used(); 481 482 print_heap_before_gc(); 483 484 { 485 FlagSetting fl(_is_gc_active, true); 486 487 bool complete = full && (max_level == (n_gens()-1)); 488 const char* gc_cause_prefix = complete ? "Full GC" : "GC"; 489 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); 490 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); 491 TraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, gclog_or_tty); 492 493 gc_prologue(complete); 494 increment_total_collections(complete); 495 496 size_t gch_prev_used = used(); 497 498 int starting_level = 0; 499 if (full) { 500 // Search for the oldest generation which will collect all younger 501 // generations, and start collection loop there. 502 for (int i = max_level; i >= 0; i--) { 503 if (_gens[i]->full_collects_younger_generations()) { 504 starting_level = i; 505 break; 506 } 507 } 508 } 509 510 bool must_restore_marks_for_biased_locking = false; 511 512 int max_level_collected = starting_level; 513 for (int i = starting_level; i <= max_level; i++) { 514 if (_gens[i]->should_collect(full, size, is_tlab)) { 515 if (i == n_gens() - 1) { // a major collection is to happen 516 if (!complete) { 517 // The full_collections increment was missed above. 518 increment_total_full_collections(); 519 } 520 pre_full_gc_dump(); // do any pre full gc dumps 521 } 522 // Timer for individual generations. Last argument is false: no CR 523 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty); 524 TraceCollectorStats tcs(_gens[i]->counters()); 525 TraceMemoryManagerStats tmms(_gens[i]->kind(),gc_cause()); 526 527 size_t prev_used = _gens[i]->used(); 528 _gens[i]->stat_record()->invocations++; 529 _gens[i]->stat_record()->accumulated_time.start(); 530 531 // Must be done anew before each collection because 532 // a previous collection will do mangling and will 533 // change top of some spaces. 534 record_gen_tops_before_GC(); 535 536 if (PrintGC && Verbose) { 537 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT, 538 i, 539 _gens[i]->stat_record()->invocations, 540 size*HeapWordSize); 541 } 542 543 if (VerifyBeforeGC && i >= VerifyGCLevel && 544 total_collections() >= VerifyGCStartAt) { 545 HandleMark hm; // Discard invalid handles created during verification 546 if (!prepared_for_verification) { 547 prepare_for_verify(); 548 prepared_for_verification = true; 549 } 550 gclog_or_tty->print(" VerifyBeforeGC:"); 551 Universe::verify(true); 552 } 553 COMPILER2_PRESENT(DerivedPointerTable::clear()); 554 555 if (!must_restore_marks_for_biased_locking && 556 _gens[i]->performs_in_place_marking()) { 557 // We perform this mark word preservation work lazily 558 // because it's only at this point that we know whether we 559 // absolutely have to do it; we want to avoid doing it for 560 // scavenge-only collections where it's unnecessary 561 must_restore_marks_for_biased_locking = true; 562 BiasedLocking::preserve_marks(); 563 } 564 565 // Do collection work 566 { 567 // Note on ref discovery: For what appear to be historical reasons, 568 // GCH enables and disabled (by enqueing) refs discovery. 569 // In the future this should be moved into the generation's 570 // collect method so that ref discovery and enqueueing concerns 571 // are local to a generation. The collect method could return 572 // an appropriate indication in the case that notification on 573 // the ref lock was needed. This will make the treatment of 574 // weak refs more uniform (and indeed remove such concerns 575 // from GCH). XXX 576 577 HandleMark hm; // Discard invalid handles created during gc 578 save_marks(); // save marks for all gens 579 // We want to discover references, but not process them yet. 580 // This mode is disabled in process_discovered_references if the 581 // generation does some collection work, or in 582 // enqueue_discovered_references if the generation returns 583 // without doing any work. 584 ReferenceProcessor* rp = _gens[i]->ref_processor(); 585 // If the discovery of ("weak") refs in this generation is 586 // atomic wrt other collectors in this configuration, we 587 // are guaranteed to have empty discovered ref lists. 588 if (rp->discovery_is_atomic()) { 589 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/); 590 rp->setup_policy(do_clear_all_soft_refs); 591 } else { 592 // collect() below will enable discovery as appropriate 593 } 594 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab); 595 if (!rp->enqueuing_is_done()) { 596 rp->enqueue_discovered_references(); 597 } else { 598 rp->set_enqueuing_is_done(false); 599 } 600 rp->verify_no_references_recorded(); 601 } 602 max_level_collected = i; 603 604 // Determine if allocation request was met. 605 if (size > 0) { 606 if (!is_tlab || _gens[i]->supports_tlab_allocation()) { 607 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) { 608 size = 0; 609 } 610 } 611 } 612 613 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 614 615 _gens[i]->stat_record()->accumulated_time.stop(); 616 617 update_gc_stats(i, full); 618 619 if (VerifyAfterGC && i >= VerifyGCLevel && 620 total_collections() >= VerifyGCStartAt) { 621 HandleMark hm; // Discard invalid handles created during verification 622 gclog_or_tty->print(" VerifyAfterGC:"); 623 Universe::verify(false); 624 } 625 626 if (PrintGCDetails) { 627 gclog_or_tty->print(":"); 628 _gens[i]->print_heap_change(prev_used); 629 } 630 } 631 } 632 633 // Update "complete" boolean wrt what actually transpired -- 634 // for instance, a promotion failure could have led to 635 // a whole heap collection. 636 complete = complete || (max_level_collected == n_gens() - 1); 637 638 if (complete) { // We did a "major" collection 639 post_full_gc_dump(); // do any post full gc dumps 640 } 641 642 if (PrintGCDetails) { 643 print_heap_change(gch_prev_used); 644 645 // Print perm gen info for full GC with PrintGCDetails flag. 646 if (complete) { 647 print_perm_heap_change(perm_prev_used); 648 } 649 } 650 651 for (int j = max_level_collected; j >= 0; j -= 1) { 652 // Adjust generation sizes. 653 _gens[j]->compute_new_size(); 654 } 655 656 if (complete) { 657 // Ask the permanent generation to adjust size for full collections 658 perm()->compute_new_size(); 659 update_full_collections_completed(); 660 } 661 662 // Track memory usage and detect low memory after GC finishes 663 MemoryService::track_memory_usage(); 664 665 gc_epilogue(complete); 666 667 if (must_restore_marks_for_biased_locking) { 668 BiasedLocking::restore_marks(); 669 } 670 } 671 672 AdaptiveSizePolicy* sp = gen_policy()->size_policy(); 673 AdaptiveSizePolicyOutput(sp, total_collections()); 674 675 print_heap_after_gc(); 676 677 #ifdef TRACESPINNING 678 ParallelTaskTerminator::print_termination_counts(); 679 #endif 680 } 681 682 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 683 return collector_policy()->satisfy_failed_allocation(size, is_tlab); 684 } 685 686 void GenCollectedHeap::set_par_threads(uint t) { 687 SharedHeap::set_par_threads(t); 688 _gen_process_strong_tasks->set_n_threads(t); 689 } 690 691 void GenCollectedHeap:: 692 gen_process_strong_roots(int level, 693 bool younger_gens_as_roots, 694 bool activate_scope, 695 bool collecting_perm_gen, 696 SharedHeap::ScanningOption so, 697 OopsInGenClosure* not_older_gens, 698 bool do_code_roots, 699 OopsInGenClosure* older_gens) { 700 // General strong roots. 701 702 if (!do_code_roots) { 703 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so, 704 not_older_gens, NULL, older_gens); 705 } else { 706 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active()); 707 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking); 708 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so, 709 not_older_gens, &code_roots, older_gens); 710 } 711 712 if (younger_gens_as_roots) { 713 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 714 for (int i = 0; i < level; i++) { 715 not_older_gens->set_generation(_gens[i]); 716 _gens[i]->oop_iterate(not_older_gens); 717 } 718 not_older_gens->reset_generation(); 719 } 720 } 721 // When collection is parallel, all threads get to cooperate to do 722 // older-gen scanning. 723 for (int i = level+1; i < _n_gens; i++) { 724 older_gens->set_generation(_gens[i]); 725 rem_set()->younger_refs_iterate(_gens[i], older_gens); 726 older_gens->reset_generation(); 727 } 728 729 _gen_process_strong_tasks->all_tasks_completed(); 730 } 731 732 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure, 733 CodeBlobClosure* code_roots, 734 OopClosure* non_root_closure) { 735 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure); 736 // "Local" "weak" refs 737 for (int i = 0; i < _n_gens; i++) { 738 _gens[i]->ref_processor()->weak_oops_do(root_closure); 739 } 740 } 741 742 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 743 void GenCollectedHeap:: \ 744 oop_since_save_marks_iterate(int level, \ 745 OopClosureType* cur, \ 746 OopClosureType* older) { \ 747 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \ 748 for (int i = level+1; i < n_gens(); i++) { \ 749 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \ 750 } \ 751 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \ 752 } 753 754 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) 755 756 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN 757 758 bool GenCollectedHeap::no_allocs_since_save_marks(int level) { 759 for (int i = level; i < _n_gens; i++) { 760 if (!_gens[i]->no_allocs_since_save_marks()) return false; 761 } 762 return perm_gen()->no_allocs_since_save_marks(); 763 } 764 765 bool GenCollectedHeap::supports_inline_contig_alloc() const { 766 return _gens[0]->supports_inline_contig_alloc(); 767 } 768 769 HeapWord** GenCollectedHeap::top_addr() const { 770 return _gens[0]->top_addr(); 771 } 772 773 HeapWord** GenCollectedHeap::end_addr() const { 774 return _gens[0]->end_addr(); 775 } 776 777 size_t GenCollectedHeap::unsafe_max_alloc() { 778 return _gens[0]->unsafe_max_alloc_nogc(); 779 } 780 781 // public collection interfaces 782 783 void GenCollectedHeap::collect(GCCause::Cause cause) { 784 if (should_do_concurrent_full_gc(cause)) { 785 #ifndef SERIALGC 786 // mostly concurrent full collection 787 collect_mostly_concurrent(cause); 788 #else // SERIALGC 789 ShouldNotReachHere(); 790 #endif // SERIALGC 791 } else { 792 #ifdef ASSERT 793 if (cause == GCCause::_scavenge_alot) { 794 // minor collection only 795 collect(cause, 0); 796 } else { 797 // Stop-the-world full collection 798 collect(cause, n_gens() - 1); 799 } 800 #else 801 // Stop-the-world full collection 802 collect(cause, n_gens() - 1); 803 #endif 804 } 805 } 806 807 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) { 808 // The caller doesn't have the Heap_lock 809 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 810 MutexLocker ml(Heap_lock); 811 collect_locked(cause, max_level); 812 } 813 814 // This interface assumes that it's being called by the 815 // vm thread. It collects the heap assuming that the 816 // heap lock is already held and that we are executing in 817 // the context of the vm thread. 818 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) { 819 assert(Thread::current()->is_VM_thread(), "Precondition#1"); 820 assert(Heap_lock->is_locked(), "Precondition#2"); 821 GCCauseSetter gcs(this, cause); 822 switch (cause) { 823 case GCCause::_heap_inspection: 824 case GCCause::_heap_dump: { 825 HandleMark hm; 826 do_full_collection(false, // don't clear all soft refs 827 n_gens() - 1); 828 break; 829 } 830 default: // XXX FIX ME 831 ShouldNotReachHere(); // Unexpected use of this function 832 } 833 } 834 835 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 836 // The caller has the Heap_lock 837 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 838 collect_locked(cause, n_gens() - 1); 839 } 840 841 // this is the private collection interface 842 // The Heap_lock is expected to be held on entry. 843 844 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) { 845 if (_preloading_shared_classes) { 846 report_out_of_shared_space(SharedPermGen); 847 } 848 // Read the GC count while holding the Heap_lock 849 unsigned int gc_count_before = total_collections(); 850 unsigned int full_gc_count_before = total_full_collections(); 851 { 852 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 853 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 854 cause, max_level); 855 VMThread::execute(&op); 856 } 857 } 858 859 #ifndef SERIALGC 860 bool GenCollectedHeap::create_cms_collector() { 861 862 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) || 863 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) && 864 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep, 865 "Unexpected generation kinds"); 866 // Skip two header words in the block content verification 867 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) 868 CMSCollector* collector = new CMSCollector( 869 (ConcurrentMarkSweepGeneration*)_gens[1], 870 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(), 871 _rem_set->as_CardTableRS(), 872 (ConcurrentMarkSweepPolicy*) collector_policy()); 873 874 if (collector == NULL || !collector->completed_initialization()) { 875 if (collector) { 876 delete collector; // Be nice in embedded situation 877 } 878 vm_shutdown_during_initialization("Could not create CMS collector"); 879 return false; 880 } 881 return true; // success 882 } 883 884 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { 885 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 886 887 MutexLocker ml(Heap_lock); 888 // Read the GC counts while holding the Heap_lock 889 unsigned int full_gc_count_before = total_full_collections(); 890 unsigned int gc_count_before = total_collections(); 891 { 892 MutexUnlocker mu(Heap_lock); 893 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 894 VMThread::execute(&op); 895 } 896 } 897 #endif // SERIALGC 898 899 900 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 901 int max_level) { 902 int local_max_level; 903 if (!incremental_collection_will_fail(false /* don't consult_young */) && 904 gc_cause() == GCCause::_gc_locker) { 905 local_max_level = 0; 906 } else { 907 local_max_level = max_level; 908 } 909 910 do_collection(true /* full */, 911 clear_all_soft_refs /* clear_all_soft_refs */, 912 0 /* size */, 913 false /* is_tlab */, 914 local_max_level /* max_level */); 915 // Hack XXX FIX ME !!! 916 // A scavenge may not have been attempted, or may have 917 // been attempted and failed, because the old gen was too full 918 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker && 919 incremental_collection_will_fail(false /* don't consult_young */)) { 920 if (PrintGCDetails) { 921 gclog_or_tty->print_cr("GC locker: Trying a full collection " 922 "because scavenge failed"); 923 } 924 // This time allow the old gen to be collected as well 925 do_collection(true /* full */, 926 clear_all_soft_refs /* clear_all_soft_refs */, 927 0 /* size */, 928 false /* is_tlab */, 929 n_gens() - 1 /* max_level */); 930 } 931 } 932 933 bool GenCollectedHeap::is_in_young(oop p) { 934 bool result = ((HeapWord*)p) < _gens[_n_gens - 1]->reserved().start(); 935 assert(result == _gens[0]->is_in_reserved(p), 936 err_msg("incorrect test - result=%d, p=" PTR_FORMAT, result, (void*)p)); 937 return result; 938 } 939 940 // Returns "TRUE" iff "p" points into the committed areas of the heap. 941 bool GenCollectedHeap::is_in(const void* p) const { 942 #ifndef ASSERT 943 guarantee(VerifyBeforeGC || 944 VerifyDuringGC || 945 VerifyBeforeExit || 946 PrintAssembly || 947 tty->count() != 0 || // already printing 948 VerifyAfterGC || 949 VMError::fatal_error_in_progress(), "too expensive"); 950 951 #endif 952 // This might be sped up with a cache of the last generation that 953 // answered yes. 954 for (int i = 0; i < _n_gens; i++) { 955 if (_gens[i]->is_in(p)) return true; 956 } 957 if (_perm_gen->as_gen()->is_in(p)) return true; 958 // Otherwise... 959 return false; 960 } 961 962 #ifdef ASSERT 963 // Don't implement this by using is_in_young(). This method is used 964 // in some cases to check that is_in_young() is correct. 965 bool GenCollectedHeap::is_in_partial_collection(const void* p) { 966 assert(is_in_reserved(p) || p == NULL, 967 "Does not work if address is non-null and outside of the heap"); 968 // The order of the generations is young (low addr), old, perm (high addr) 969 return p < _gens[_n_gens - 2]->reserved().end() && p != NULL; 970 } 971 #endif 972 973 void GenCollectedHeap::oop_iterate(OopClosure* cl) { 974 for (int i = 0; i < _n_gens; i++) { 975 _gens[i]->oop_iterate(cl); 976 } 977 } 978 979 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) { 980 for (int i = 0; i < _n_gens; i++) { 981 _gens[i]->oop_iterate(mr, cl); 982 } 983 } 984 985 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 986 for (int i = 0; i < _n_gens; i++) { 987 _gens[i]->object_iterate(cl); 988 } 989 perm_gen()->object_iterate(cl); 990 } 991 992 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { 993 for (int i = 0; i < _n_gens; i++) { 994 _gens[i]->safe_object_iterate(cl); 995 } 996 perm_gen()->safe_object_iterate(cl); 997 } 998 999 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) { 1000 for (int i = 0; i < _n_gens; i++) { 1001 _gens[i]->object_iterate_since_last_GC(cl); 1002 } 1003 } 1004 1005 Space* GenCollectedHeap::space_containing(const void* addr) const { 1006 for (int i = 0; i < _n_gens; i++) { 1007 Space* res = _gens[i]->space_containing(addr); 1008 if (res != NULL) return res; 1009 } 1010 Space* res = perm_gen()->space_containing(addr); 1011 if (res != NULL) return res; 1012 // Otherwise... 1013 assert(false, "Could not find containing space"); 1014 return NULL; 1015 } 1016 1017 1018 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 1019 assert(is_in_reserved(addr), "block_start of address outside of heap"); 1020 for (int i = 0; i < _n_gens; i++) { 1021 if (_gens[i]->is_in_reserved(addr)) { 1022 assert(_gens[i]->is_in(addr), 1023 "addr should be in allocated part of generation"); 1024 return _gens[i]->block_start(addr); 1025 } 1026 } 1027 if (perm_gen()->is_in_reserved(addr)) { 1028 assert(perm_gen()->is_in(addr), 1029 "addr should be in allocated part of perm gen"); 1030 return perm_gen()->block_start(addr); 1031 } 1032 assert(false, "Some generation should contain the address"); 1033 return NULL; 1034 } 1035 1036 size_t GenCollectedHeap::block_size(const HeapWord* addr) const { 1037 assert(is_in_reserved(addr), "block_size of address outside of heap"); 1038 for (int i = 0; i < _n_gens; i++) { 1039 if (_gens[i]->is_in_reserved(addr)) { 1040 assert(_gens[i]->is_in(addr), 1041 "addr should be in allocated part of generation"); 1042 return _gens[i]->block_size(addr); 1043 } 1044 } 1045 if (perm_gen()->is_in_reserved(addr)) { 1046 assert(perm_gen()->is_in(addr), 1047 "addr should be in allocated part of perm gen"); 1048 return perm_gen()->block_size(addr); 1049 } 1050 assert(false, "Some generation should contain the address"); 1051 return 0; 1052 } 1053 1054 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 1055 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 1056 assert(block_start(addr) == addr, "addr must be a block start"); 1057 for (int i = 0; i < _n_gens; i++) { 1058 if (_gens[i]->is_in_reserved(addr)) { 1059 return _gens[i]->block_is_obj(addr); 1060 } 1061 } 1062 if (perm_gen()->is_in_reserved(addr)) { 1063 return perm_gen()->block_is_obj(addr); 1064 } 1065 assert(false, "Some generation should contain the address"); 1066 return false; 1067 } 1068 1069 bool GenCollectedHeap::supports_tlab_allocation() const { 1070 for (int i = 0; i < _n_gens; i += 1) { 1071 if (_gens[i]->supports_tlab_allocation()) { 1072 return true; 1073 } 1074 } 1075 return false; 1076 } 1077 1078 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 1079 size_t result = 0; 1080 for (int i = 0; i < _n_gens; i += 1) { 1081 if (_gens[i]->supports_tlab_allocation()) { 1082 result += _gens[i]->tlab_capacity(); 1083 } 1084 } 1085 return result; 1086 } 1087 1088 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1089 size_t result = 0; 1090 for (int i = 0; i < _n_gens; i += 1) { 1091 if (_gens[i]->supports_tlab_allocation()) { 1092 result += _gens[i]->unsafe_max_tlab_alloc(); 1093 } 1094 } 1095 return result; 1096 } 1097 1098 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { 1099 bool gc_overhead_limit_was_exceeded; 1100 return collector_policy()->mem_allocate_work(size /* size */, 1101 true /* is_tlab */, 1102 &gc_overhead_limit_was_exceeded); 1103 } 1104 1105 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1106 // from the list headed by "*prev_ptr". 1107 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1108 bool first = true; 1109 size_t min_size = 0; // "first" makes this conceptually infinite. 1110 ScratchBlock **smallest_ptr, *smallest; 1111 ScratchBlock *cur = *prev_ptr; 1112 while (cur) { 1113 assert(*prev_ptr == cur, "just checking"); 1114 if (first || cur->num_words < min_size) { 1115 smallest_ptr = prev_ptr; 1116 smallest = cur; 1117 min_size = smallest->num_words; 1118 first = false; 1119 } 1120 prev_ptr = &cur->next; 1121 cur = cur->next; 1122 } 1123 smallest = *smallest_ptr; 1124 *smallest_ptr = smallest->next; 1125 return smallest; 1126 } 1127 1128 // Sort the scratch block list headed by res into decreasing size order, 1129 // and set "res" to the result. 1130 static void sort_scratch_list(ScratchBlock*& list) { 1131 ScratchBlock* sorted = NULL; 1132 ScratchBlock* unsorted = list; 1133 while (unsorted) { 1134 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1135 smallest->next = sorted; 1136 sorted = smallest; 1137 } 1138 list = sorted; 1139 } 1140 1141 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1142 size_t max_alloc_words) { 1143 ScratchBlock* res = NULL; 1144 for (int i = 0; i < _n_gens; i++) { 1145 _gens[i]->contribute_scratch(res, requestor, max_alloc_words); 1146 } 1147 sort_scratch_list(res); 1148 return res; 1149 } 1150 1151 void GenCollectedHeap::release_scratch() { 1152 for (int i = 0; i < _n_gens; i++) { 1153 _gens[i]->reset_scratch(); 1154 } 1155 } 1156 1157 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1158 void do_generation(Generation* gen) { 1159 gen->prepare_for_verify(); 1160 } 1161 }; 1162 1163 void GenCollectedHeap::prepare_for_verify() { 1164 ensure_parsability(false); // no need to retire TLABs 1165 GenPrepareForVerifyClosure blk; 1166 generation_iterate(&blk, false); 1167 perm_gen()->prepare_for_verify(); 1168 } 1169 1170 1171 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1172 bool old_to_young) { 1173 if (old_to_young) { 1174 for (int i = _n_gens-1; i >= 0; i--) { 1175 cl->do_generation(_gens[i]); 1176 } 1177 } else { 1178 for (int i = 0; i < _n_gens; i++) { 1179 cl->do_generation(_gens[i]); 1180 } 1181 } 1182 } 1183 1184 void GenCollectedHeap::space_iterate(SpaceClosure* cl) { 1185 for (int i = 0; i < _n_gens; i++) { 1186 _gens[i]->space_iterate(cl, true); 1187 } 1188 perm_gen()->space_iterate(cl, true); 1189 } 1190 1191 bool GenCollectedHeap::is_maximal_no_gc() const { 1192 for (int i = 0; i < _n_gens; i++) { // skip perm gen 1193 if (!_gens[i]->is_maximal_no_gc()) { 1194 return false; 1195 } 1196 } 1197 return true; 1198 } 1199 1200 void GenCollectedHeap::save_marks() { 1201 for (int i = 0; i < _n_gens; i++) { 1202 _gens[i]->save_marks(); 1203 } 1204 perm_gen()->save_marks(); 1205 } 1206 1207 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) { 1208 for (int i = 0; i <= collectedGen; i++) { 1209 _gens[i]->compute_new_size(); 1210 } 1211 } 1212 1213 GenCollectedHeap* GenCollectedHeap::heap() { 1214 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1215 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap"); 1216 return _gch; 1217 } 1218 1219 1220 void GenCollectedHeap::prepare_for_compaction() { 1221 Generation* scanning_gen = _gens[_n_gens-1]; 1222 // Start by compacting into same gen. 1223 CompactPoint cp(scanning_gen, NULL, NULL); 1224 while (scanning_gen != NULL) { 1225 scanning_gen->prepare_for_compaction(&cp); 1226 scanning_gen = prev_gen(scanning_gen); 1227 } 1228 } 1229 1230 GCStats* GenCollectedHeap::gc_stats(int level) const { 1231 return _gens[level]->gc_stats(); 1232 } 1233 1234 void GenCollectedHeap::verify(bool silent, VerifyOption option /* ignored */) { 1235 if (!silent) { 1236 gclog_or_tty->print("permgen "); 1237 } 1238 perm_gen()->verify(); 1239 for (int i = _n_gens-1; i >= 0; i--) { 1240 Generation* g = _gens[i]; 1241 if (!silent) { 1242 gclog_or_tty->print(g->name()); 1243 gclog_or_tty->print(" "); 1244 } 1245 g->verify(); 1246 } 1247 if (!silent) { 1248 gclog_or_tty->print("remset "); 1249 } 1250 rem_set()->verify(); 1251 } 1252 1253 void GenCollectedHeap::print_on(outputStream* st) const { 1254 for (int i = 0; i < _n_gens; i++) { 1255 _gens[i]->print_on(st); 1256 } 1257 perm_gen()->print_on(st); 1258 } 1259 1260 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1261 if (workers() != NULL) { 1262 workers()->threads_do(tc); 1263 } 1264 #ifndef SERIALGC 1265 if (UseConcMarkSweepGC) { 1266 ConcurrentMarkSweepThread::threads_do(tc); 1267 } 1268 #endif // SERIALGC 1269 } 1270 1271 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1272 #ifndef SERIALGC 1273 if (UseParNewGC) { 1274 workers()->print_worker_threads_on(st); 1275 } 1276 if (UseConcMarkSweepGC) { 1277 ConcurrentMarkSweepThread::print_all_on(st); 1278 } 1279 #endif // SERIALGC 1280 } 1281 1282 void GenCollectedHeap::print_tracing_info() const { 1283 if (TraceGen0Time) { 1284 get_gen(0)->print_summary_info(); 1285 } 1286 if (TraceGen1Time) { 1287 get_gen(1)->print_summary_info(); 1288 } 1289 } 1290 1291 void GenCollectedHeap::print_heap_change(size_t prev_used) const { 1292 if (PrintGCDetails && Verbose) { 1293 gclog_or_tty->print(" " SIZE_FORMAT 1294 "->" SIZE_FORMAT 1295 "(" SIZE_FORMAT ")", 1296 prev_used, used(), capacity()); 1297 } else { 1298 gclog_or_tty->print(" " SIZE_FORMAT "K" 1299 "->" SIZE_FORMAT "K" 1300 "(" SIZE_FORMAT "K)", 1301 prev_used / K, used() / K, capacity() / K); 1302 } 1303 } 1304 1305 //New method to print perm gen info with PrintGCDetails flag 1306 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const { 1307 gclog_or_tty->print(", [%s :", perm_gen()->short_name()); 1308 perm_gen()->print_heap_change(perm_prev_used); 1309 gclog_or_tty->print("]"); 1310 } 1311 1312 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1313 private: 1314 bool _full; 1315 public: 1316 void do_generation(Generation* gen) { 1317 gen->gc_prologue(_full); 1318 } 1319 GenGCPrologueClosure(bool full) : _full(full) {}; 1320 }; 1321 1322 void GenCollectedHeap::gc_prologue(bool full) { 1323 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1324 1325 always_do_update_barrier = false; 1326 // Fill TLAB's and such 1327 CollectedHeap::accumulate_statistics_all_tlabs(); 1328 ensure_parsability(true); // retire TLABs 1329 1330 // Call allocation profiler 1331 AllocationProfiler::iterate_since_last_gc(); 1332 // Walk generations 1333 GenGCPrologueClosure blk(full); 1334 generation_iterate(&blk, false); // not old-to-young. 1335 perm_gen()->gc_prologue(full); 1336 }; 1337 1338 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1339 private: 1340 bool _full; 1341 public: 1342 void do_generation(Generation* gen) { 1343 gen->gc_epilogue(_full); 1344 } 1345 GenGCEpilogueClosure(bool full) : _full(full) {}; 1346 }; 1347 1348 void GenCollectedHeap::gc_epilogue(bool full) { 1349 #ifdef COMPILER2 1350 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1351 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1352 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1353 #endif /* COMPILER2 */ 1354 1355 resize_all_tlabs(); 1356 1357 GenGCEpilogueClosure blk(full); 1358 generation_iterate(&blk, false); // not old-to-young. 1359 perm_gen()->gc_epilogue(full); 1360 1361 if (!CleanChunkPoolAsync) { 1362 Chunk::clean_chunk_pool(); 1363 } 1364 1365 always_do_update_barrier = UseConcMarkSweepGC; 1366 }; 1367 1368 #ifndef PRODUCT 1369 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1370 private: 1371 public: 1372 void do_generation(Generation* gen) { 1373 gen->record_spaces_top(); 1374 } 1375 }; 1376 1377 void GenCollectedHeap::record_gen_tops_before_GC() { 1378 if (ZapUnusedHeapArea) { 1379 GenGCSaveTopsBeforeGCClosure blk; 1380 generation_iterate(&blk, false); // not old-to-young. 1381 perm_gen()->record_spaces_top(); 1382 } 1383 } 1384 #endif // not PRODUCT 1385 1386 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1387 public: 1388 void do_generation(Generation* gen) { 1389 gen->ensure_parsability(); 1390 } 1391 }; 1392 1393 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1394 CollectedHeap::ensure_parsability(retire_tlabs); 1395 GenEnsureParsabilityClosure ep_cl; 1396 generation_iterate(&ep_cl, false); 1397 perm_gen()->ensure_parsability(); 1398 } 1399 1400 oop GenCollectedHeap::handle_failed_promotion(Generation* gen, 1401 oop obj, 1402 size_t obj_size) { 1403 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1404 HeapWord* result = NULL; 1405 1406 // First give each higher generation a chance to allocate the promoted object. 1407 Generation* allocator = next_gen(gen); 1408 if (allocator != NULL) { 1409 do { 1410 result = allocator->allocate(obj_size, false); 1411 } while (result == NULL && (allocator = next_gen(allocator)) != NULL); 1412 } 1413 1414 if (result == NULL) { 1415 // Then give gen and higher generations a chance to expand and allocate the 1416 // object. 1417 do { 1418 result = gen->expand_and_allocate(obj_size, false); 1419 } while (result == NULL && (gen = next_gen(gen)) != NULL); 1420 } 1421 1422 if (result != NULL) { 1423 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 1424 } 1425 return oop(result); 1426 } 1427 1428 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1429 jlong _time; // in ms 1430 jlong _now; // in ms 1431 1432 public: 1433 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1434 1435 jlong time() { return _time; } 1436 1437 void do_generation(Generation* gen) { 1438 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1439 } 1440 }; 1441 1442 jlong GenCollectedHeap::millis_since_last_gc() { 1443 // We need a monotonically non-deccreasing time in ms but 1444 // os::javaTimeMillis() does not guarantee monotonicity. 1445 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; 1446 GenTimeOfLastGCClosure tolgc_cl(now); 1447 // iterate over generations getting the oldest 1448 // time that a generation was collected 1449 generation_iterate(&tolgc_cl, false); 1450 tolgc_cl.do_generation(perm_gen()); 1451 1452 // javaTimeNanos() is guaranteed to be monotonically non-decreasing 1453 // provided the underlying platform provides such a time source 1454 // (and it is bug free). So we still have to guard against getting 1455 // back a time later than 'now'. 1456 jlong retVal = now - tolgc_cl.time(); 1457 if (retVal < 0) { 1458 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, retVal);) 1459 return 0; 1460 } 1461 return retVal; 1462 }