1 /* 2 * Copyright (c) 2000, 2010, 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_will_fail(); 179 clear_last_incremental_collection_failed(); 180 181 #ifndef SERIALGC 182 // If we are running CMS, create the collector responsible 183 // for collecting the CMS generations. 184 if (collector_policy()->is_concurrent_mark_sweep_policy()) { 185 bool success = create_cms_collector(); 186 if (!success) return JNI_ENOMEM; 187 } 188 #endif // SERIALGC 189 190 return JNI_OK; 191 } 192 193 194 char* GenCollectedHeap::allocate(size_t alignment, 195 PermanentGenerationSpec* perm_gen_spec, 196 size_t* _total_reserved, 197 int* _n_covered_regions, 198 ReservedSpace* heap_rs){ 199 const char overflow_msg[] = "The size of the object heap + VM data exceeds " 200 "the maximum representable size"; 201 202 // Now figure out the total size. 203 size_t total_reserved = 0; 204 int n_covered_regions = 0; 205 const size_t pageSize = UseLargePages ? 206 os::large_page_size() : os::vm_page_size(); 207 208 for (int i = 0; i < _n_gens; i++) { 209 total_reserved += _gen_specs[i]->max_size(); 210 if (total_reserved < _gen_specs[i]->max_size()) { 211 vm_exit_during_initialization(overflow_msg); 212 } 213 n_covered_regions += _gen_specs[i]->n_covered_regions(); 214 } 215 assert(total_reserved % pageSize == 0, 216 err_msg("Gen size; total_reserved=" SIZE_FORMAT ", pageSize=" 217 SIZE_FORMAT, total_reserved, pageSize)); 218 total_reserved += perm_gen_spec->max_size(); 219 assert(total_reserved % pageSize == 0, 220 err_msg("Perm size; total_reserved=" SIZE_FORMAT ", pageSize=" 221 SIZE_FORMAT ", perm gen max=" SIZE_FORMAT, total_reserved, 222 pageSize, perm_gen_spec->max_size())); 223 224 if (total_reserved < perm_gen_spec->max_size()) { 225 vm_exit_during_initialization(overflow_msg); 226 } 227 n_covered_regions += perm_gen_spec->n_covered_regions(); 228 229 // Add the size of the data area which shares the same reserved area 230 // as the heap, but which is not actually part of the heap. 231 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size(); 232 233 total_reserved += s; 234 if (total_reserved < s) { 235 vm_exit_during_initialization(overflow_msg); 236 } 237 238 if (UseLargePages) { 239 assert(total_reserved != 0, "total_reserved cannot be 0"); 240 total_reserved = round_to(total_reserved, os::large_page_size()); 241 if (total_reserved < os::large_page_size()) { 242 vm_exit_during_initialization(overflow_msg); 243 } 244 } 245 246 // Calculate the address at which the heap must reside in order for 247 // the shared data to be at the required address. 248 249 char* heap_address; 250 if (UseSharedSpaces) { 251 252 // Calculate the address of the first word beyond the heap. 253 FileMapInfo* mapinfo = FileMapInfo::current_info(); 254 int lr = CompactingPermGenGen::n_regions - 1; 255 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment); 256 heap_address = mapinfo->region_base(lr) + capacity; 257 258 // Calculate the address of the first word of the heap. 259 heap_address -= total_reserved; 260 } else { 261 heap_address = NULL; // any address will do. 262 if (UseCompressedOops) { 263 heap_address = Universe::preferred_heap_base(total_reserved, Universe::UnscaledNarrowOop); 264 *_total_reserved = total_reserved; 265 *_n_covered_regions = n_covered_regions; 266 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 267 UseLargePages, heap_address); 268 269 if (heap_address != NULL && !heap_rs->is_reserved()) { 270 // Failed to reserve at specified address - the requested memory 271 // region is taken already, for example, by 'java' launcher. 272 // Try again to reserver heap higher. 273 heap_address = Universe::preferred_heap_base(total_reserved, Universe::ZeroBasedNarrowOop); 274 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 275 UseLargePages, heap_address); 276 277 if (heap_address != NULL && !heap_rs->is_reserved()) { 278 // Failed to reserve at specified address again - give up. 279 heap_address = Universe::preferred_heap_base(total_reserved, Universe::HeapBasedNarrowOop); 280 assert(heap_address == NULL, ""); 281 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 282 UseLargePages, heap_address); 283 } 284 } 285 return heap_address; 286 } 287 } 288 289 *_total_reserved = total_reserved; 290 *_n_covered_regions = n_covered_regions; 291 *heap_rs = ReservedHeapSpace(total_reserved, alignment, 292 UseLargePages, heap_address); 293 294 return heap_address; 295 } 296 297 298 void GenCollectedHeap::post_initialize() { 299 SharedHeap::post_initialize(); 300 TwoGenerationCollectorPolicy *policy = 301 (TwoGenerationCollectorPolicy *)collector_policy(); 302 guarantee(policy->is_two_generation_policy(), "Illegal policy type"); 303 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0); 304 assert(def_new_gen->kind() == Generation::DefNew || 305 def_new_gen->kind() == Generation::ParNew || 306 def_new_gen->kind() == Generation::ASParNew, 307 "Wrong generation kind"); 308 309 Generation* old_gen = get_gen(1); 310 assert(old_gen->kind() == Generation::ConcurrentMarkSweep || 311 old_gen->kind() == Generation::ASConcurrentMarkSweep || 312 old_gen->kind() == Generation::MarkSweepCompact, 313 "Wrong generation kind"); 314 315 policy->initialize_size_policy(def_new_gen->eden()->capacity(), 316 old_gen->capacity(), 317 def_new_gen->from()->capacity()); 318 policy->initialize_gc_policy_counters(); 319 } 320 321 void GenCollectedHeap::ref_processing_init() { 322 SharedHeap::ref_processing_init(); 323 for (int i = 0; i < _n_gens; i++) { 324 _gens[i]->ref_processor_init(); 325 } 326 } 327 328 size_t GenCollectedHeap::capacity() const { 329 size_t res = 0; 330 for (int i = 0; i < _n_gens; i++) { 331 res += _gens[i]->capacity(); 332 } 333 return res; 334 } 335 336 size_t GenCollectedHeap::used() const { 337 size_t res = 0; 338 for (int i = 0; i < _n_gens; i++) { 339 res += _gens[i]->used(); 340 } 341 return res; 342 } 343 344 // Save the "used_region" for generations level and lower, 345 // and, if perm is true, for perm gen. 346 void GenCollectedHeap::save_used_regions(int level, bool perm) { 347 assert(level < _n_gens, "Illegal level parameter"); 348 for (int i = level; i >= 0; i--) { 349 _gens[i]->save_used_region(); 350 } 351 if (perm) { 352 perm_gen()->save_used_region(); 353 } 354 } 355 356 size_t GenCollectedHeap::max_capacity() const { 357 size_t res = 0; 358 for (int i = 0; i < _n_gens; i++) { 359 res += _gens[i]->max_capacity(); 360 } 361 return res; 362 } 363 364 // Update the _full_collections_completed counter 365 // at the end of a stop-world full GC. 366 unsigned int GenCollectedHeap::update_full_collections_completed() { 367 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 368 assert(_full_collections_completed <= _total_full_collections, 369 "Can't complete more collections than were started"); 370 _full_collections_completed = _total_full_collections; 371 ml.notify_all(); 372 return _full_collections_completed; 373 } 374 375 // Update the _full_collections_completed counter, as appropriate, 376 // at the end of a concurrent GC cycle. Note the conditional update 377 // below to allow this method to be called by a concurrent collector 378 // without synchronizing in any manner with the VM thread (which 379 // may already have initiated a STW full collection "concurrently"). 380 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { 381 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); 382 assert((_full_collections_completed <= _total_full_collections) && 383 (count <= _total_full_collections), 384 "Can't complete more collections than were started"); 385 if (count > _full_collections_completed) { 386 _full_collections_completed = count; 387 ml.notify_all(); 388 } 389 return _full_collections_completed; 390 } 391 392 393 #ifndef PRODUCT 394 // Override of memory state checking method in CollectedHeap: 395 // Some collectors (CMS for example) can't have badHeapWordVal written 396 // in the first two words of an object. (For instance , in the case of 397 // CMS these words hold state used to synchronize between certain 398 // (concurrent) GC steps and direct allocating mutators.) 399 // The skip_header_HeapWords() method below, allows us to skip 400 // over the requisite number of HeapWord's. Note that (for 401 // generational collectors) this means that those many words are 402 // skipped in each object, irrespective of the generation in which 403 // that object lives. The resultant loss of precision seems to be 404 // harmless and the pain of avoiding that imprecision appears somewhat 405 // higher than we are prepared to pay for such rudimentary debugging 406 // support. 407 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, 408 size_t size) { 409 if (CheckMemoryInitialization && ZapUnusedHeapArea) { 410 // We are asked to check a size in HeapWords, 411 // but the memory is mangled in juint words. 412 juint* start = (juint*) (addr + skip_header_HeapWords()); 413 juint* end = (juint*) (addr + size); 414 for (juint* slot = start; slot < end; slot += 1) { 415 assert(*slot == badHeapWordVal, 416 "Found non badHeapWordValue in pre-allocation check"); 417 } 418 } 419 } 420 #endif 421 422 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, 423 bool is_tlab, 424 bool first_only) { 425 HeapWord* res; 426 for (int i = 0; i < _n_gens; i++) { 427 if (_gens[i]->should_allocate(size, is_tlab)) { 428 res = _gens[i]->allocate(size, is_tlab); 429 if (res != NULL) return res; 430 else if (first_only) break; 431 } 432 } 433 // Otherwise... 434 return NULL; 435 } 436 437 HeapWord* GenCollectedHeap::mem_allocate(size_t size, 438 bool is_large_noref, 439 bool is_tlab, 440 bool* gc_overhead_limit_was_exceeded) { 441 return collector_policy()->mem_allocate_work(size, 442 is_tlab, 443 gc_overhead_limit_was_exceeded); 444 } 445 446 bool GenCollectedHeap::must_clear_all_soft_refs() { 447 return _gc_cause == GCCause::_last_ditch_collection; 448 } 449 450 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { 451 return UseConcMarkSweepGC && 452 ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) || 453 (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)); 454 } 455 456 void GenCollectedHeap::do_collection(bool full, 457 bool clear_all_soft_refs, 458 size_t size, 459 bool is_tlab, 460 int max_level) { 461 bool prepared_for_verification = false; 462 ResourceMark rm; 463 DEBUG_ONLY(Thread* my_thread = Thread::current();) 464 465 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); 466 assert(my_thread->is_VM_thread() || 467 my_thread->is_ConcurrentGC_thread(), 468 "incorrect thread type capability"); 469 assert(Heap_lock->is_locked(), 470 "the requesting thread should have the Heap_lock"); 471 guarantee(!is_gc_active(), "collection is not reentrant"); 472 assert(max_level < n_gens(), "sanity check"); 473 474 if (GC_locker::check_active_before_gc()) { 475 return; // GC is disabled (e.g. JNI GetXXXCritical operation) 476 } 477 478 const bool do_clear_all_soft_refs = clear_all_soft_refs || 479 collector_policy()->should_clear_all_soft_refs(); 480 481 ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy()); 482 483 const size_t perm_prev_used = perm_gen()->used(); 484 485 if (PrintHeapAtGC) { 486 Universe::print_heap_before_gc(); 487 if (Verbose) { 488 gclog_or_tty->print_cr("GC Cause: %s", GCCause::to_string(gc_cause())); 489 } 490 } 491 492 { 493 FlagSetting fl(_is_gc_active, true); 494 495 bool complete = full && (max_level == (n_gens()-1)); 496 const char* gc_cause_str = "GC "; 497 if (complete) { 498 GCCause::Cause cause = gc_cause(); 499 if (cause == GCCause::_java_lang_system_gc) { 500 gc_cause_str = "Full GC (System) "; 501 } else { 502 gc_cause_str = "Full GC "; 503 } 504 } 505 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); 506 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); 507 TraceTime t(gc_cause_str, PrintGCDetails, false, gclog_or_tty); 508 509 gc_prologue(complete); 510 increment_total_collections(complete); 511 512 size_t gch_prev_used = used(); 513 514 int starting_level = 0; 515 if (full) { 516 // Search for the oldest generation which will collect all younger 517 // generations, and start collection loop there. 518 for (int i = max_level; i >= 0; i--) { 519 if (_gens[i]->full_collects_younger_generations()) { 520 starting_level = i; 521 break; 522 } 523 } 524 } 525 526 bool must_restore_marks_for_biased_locking = false; 527 528 int max_level_collected = starting_level; 529 for (int i = starting_level; i <= max_level; i++) { 530 if (_gens[i]->should_collect(full, size, is_tlab)) { 531 if (i == n_gens() - 1) { // a major collection is to happen 532 if (!complete) { 533 // The full_collections increment was missed above. 534 increment_total_full_collections(); 535 } 536 pre_full_gc_dump(); // do any pre full gc dumps 537 } 538 // Timer for individual generations. Last argument is false: no CR 539 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty); 540 TraceCollectorStats tcs(_gens[i]->counters()); 541 TraceMemoryManagerStats tmms(_gens[i]->kind()); 542 543 size_t prev_used = _gens[i]->used(); 544 _gens[i]->stat_record()->invocations++; 545 _gens[i]->stat_record()->accumulated_time.start(); 546 547 // Must be done anew before each collection because 548 // a previous collection will do mangling and will 549 // change top of some spaces. 550 record_gen_tops_before_GC(); 551 552 if (PrintGC && Verbose) { 553 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT, 554 i, 555 _gens[i]->stat_record()->invocations, 556 size*HeapWordSize); 557 } 558 559 if (VerifyBeforeGC && i >= VerifyGCLevel && 560 total_collections() >= VerifyGCStartAt) { 561 HandleMark hm; // Discard invalid handles created during verification 562 if (!prepared_for_verification) { 563 prepare_for_verify(); 564 prepared_for_verification = true; 565 } 566 gclog_or_tty->print(" VerifyBeforeGC:"); 567 Universe::verify(true); 568 } 569 COMPILER2_PRESENT(DerivedPointerTable::clear()); 570 571 if (!must_restore_marks_for_biased_locking && 572 _gens[i]->performs_in_place_marking()) { 573 // We perform this mark word preservation work lazily 574 // because it's only at this point that we know whether we 575 // absolutely have to do it; we want to avoid doing it for 576 // scavenge-only collections where it's unnecessary 577 must_restore_marks_for_biased_locking = true; 578 BiasedLocking::preserve_marks(); 579 } 580 581 // Do collection work 582 { 583 // Note on ref discovery: For what appear to be historical reasons, 584 // GCH enables and disabled (by enqueing) refs discovery. 585 // In the future this should be moved into the generation's 586 // collect method so that ref discovery and enqueueing concerns 587 // are local to a generation. The collect method could return 588 // an appropriate indication in the case that notification on 589 // the ref lock was needed. This will make the treatment of 590 // weak refs more uniform (and indeed remove such concerns 591 // from GCH). XXX 592 593 HandleMark hm; // Discard invalid handles created during gc 594 save_marks(); // save marks for all gens 595 // We want to discover references, but not process them yet. 596 // This mode is disabled in process_discovered_references if the 597 // generation does some collection work, or in 598 // enqueue_discovered_references if the generation returns 599 // without doing any work. 600 ReferenceProcessor* rp = _gens[i]->ref_processor(); 601 // If the discovery of ("weak") refs in this generation is 602 // atomic wrt other collectors in this configuration, we 603 // are guaranteed to have empty discovered ref lists. 604 if (rp->discovery_is_atomic()) { 605 rp->verify_no_references_recorded(); 606 rp->enable_discovery(); 607 rp->setup_policy(do_clear_all_soft_refs); 608 } else { 609 // collect() below will enable discovery as appropriate 610 } 611 _gens[i]->collect(full, do_clear_all_soft_refs, size, is_tlab); 612 if (!rp->enqueuing_is_done()) { 613 rp->enqueue_discovered_references(); 614 } else { 615 rp->set_enqueuing_is_done(false); 616 } 617 rp->verify_no_references_recorded(); 618 } 619 max_level_collected = i; 620 621 // Determine if allocation request was met. 622 if (size > 0) { 623 if (!is_tlab || _gens[i]->supports_tlab_allocation()) { 624 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) { 625 size = 0; 626 } 627 } 628 } 629 630 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 631 632 _gens[i]->stat_record()->accumulated_time.stop(); 633 634 update_gc_stats(i, full); 635 636 if (VerifyAfterGC && i >= VerifyGCLevel && 637 total_collections() >= VerifyGCStartAt) { 638 HandleMark hm; // Discard invalid handles created during verification 639 gclog_or_tty->print(" VerifyAfterGC:"); 640 Universe::verify(false); 641 } 642 643 if (PrintGCDetails) { 644 gclog_or_tty->print(":"); 645 _gens[i]->print_heap_change(prev_used); 646 } 647 } 648 } 649 650 // Update "complete" boolean wrt what actually transpired -- 651 // for instance, a promotion failure could have led to 652 // a whole heap collection. 653 complete = complete || (max_level_collected == n_gens() - 1); 654 655 if (complete) { // We did a "major" collection 656 post_full_gc_dump(); // do any post full gc dumps 657 } 658 659 if (PrintGCDetails) { 660 print_heap_change(gch_prev_used); 661 662 // Print perm gen info for full GC with PrintGCDetails flag. 663 if (complete) { 664 print_perm_heap_change(perm_prev_used); 665 } 666 } 667 668 for (int j = max_level_collected; j >= 0; j -= 1) { 669 // Adjust generation sizes. 670 _gens[j]->compute_new_size(); 671 } 672 673 if (complete) { 674 // Ask the permanent generation to adjust size for full collections 675 perm()->compute_new_size(); 676 update_full_collections_completed(); 677 } 678 679 // Track memory usage and detect low memory after GC finishes 680 MemoryService::track_memory_usage(); 681 682 gc_epilogue(complete); 683 684 if (must_restore_marks_for_biased_locking) { 685 BiasedLocking::restore_marks(); 686 } 687 } 688 689 AdaptiveSizePolicy* sp = gen_policy()->size_policy(); 690 AdaptiveSizePolicyOutput(sp, total_collections()); 691 692 if (PrintHeapAtGC) { 693 Universe::print_heap_after_gc(); 694 } 695 696 #ifdef TRACESPINNING 697 ParallelTaskTerminator::print_termination_counts(); 698 #endif 699 700 if (ExitAfterGCNum > 0 && total_collections() == ExitAfterGCNum) { 701 tty->print_cr("Stopping after GC #%d", ExitAfterGCNum); 702 vm_exit(-1); 703 } 704 } 705 706 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { 707 return collector_policy()->satisfy_failed_allocation(size, is_tlab); 708 } 709 710 void GenCollectedHeap::set_par_threads(int t) { 711 SharedHeap::set_par_threads(t); 712 _gen_process_strong_tasks->set_n_threads(t); 713 } 714 715 class AssertIsPermClosure: public OopClosure { 716 public: 717 void do_oop(oop* p) { 718 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm."); 719 } 720 void do_oop(narrowOop* p) { ShouldNotReachHere(); } 721 }; 722 static AssertIsPermClosure assert_is_perm_closure; 723 724 void GenCollectedHeap:: 725 gen_process_strong_roots(int level, 726 bool younger_gens_as_roots, 727 bool activate_scope, 728 bool collecting_perm_gen, 729 SharedHeap::ScanningOption so, 730 OopsInGenClosure* not_older_gens, 731 bool do_code_roots, 732 OopsInGenClosure* older_gens) { 733 // General strong roots. 734 735 if (!do_code_roots) { 736 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so, 737 not_older_gens, NULL, older_gens); 738 } else { 739 bool do_code_marking = (activate_scope || nmethod::oops_do_marking_is_active()); 740 CodeBlobToOopClosure code_roots(not_older_gens, /*do_marking=*/ do_code_marking); 741 SharedHeap::process_strong_roots(activate_scope, collecting_perm_gen, so, 742 not_older_gens, &code_roots, older_gens); 743 } 744 745 if (younger_gens_as_roots) { 746 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 747 for (int i = 0; i < level; i++) { 748 not_older_gens->set_generation(_gens[i]); 749 _gens[i]->oop_iterate(not_older_gens); 750 } 751 not_older_gens->reset_generation(); 752 } 753 } 754 // When collection is parallel, all threads get to cooperate to do 755 // older-gen scanning. 756 for (int i = level+1; i < _n_gens; i++) { 757 older_gens->set_generation(_gens[i]); 758 rem_set()->younger_refs_iterate(_gens[i], older_gens); 759 older_gens->reset_generation(); 760 } 761 762 _gen_process_strong_tasks->all_tasks_completed(); 763 } 764 765 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure, 766 CodeBlobClosure* code_roots, 767 OopClosure* non_root_closure) { 768 SharedHeap::process_weak_roots(root_closure, code_roots, non_root_closure); 769 // "Local" "weak" refs 770 for (int i = 0; i < _n_gens; i++) { 771 _gens[i]->ref_processor()->weak_oops_do(root_closure); 772 } 773 } 774 775 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 776 void GenCollectedHeap:: \ 777 oop_since_save_marks_iterate(int level, \ 778 OopClosureType* cur, \ 779 OopClosureType* older) { \ 780 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \ 781 for (int i = level+1; i < n_gens(); i++) { \ 782 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \ 783 } \ 784 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \ 785 } 786 787 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) 788 789 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN 790 791 bool GenCollectedHeap::no_allocs_since_save_marks(int level) { 792 for (int i = level; i < _n_gens; i++) { 793 if (!_gens[i]->no_allocs_since_save_marks()) return false; 794 } 795 return perm_gen()->no_allocs_since_save_marks(); 796 } 797 798 bool GenCollectedHeap::supports_inline_contig_alloc() const { 799 return _gens[0]->supports_inline_contig_alloc(); 800 } 801 802 HeapWord** GenCollectedHeap::top_addr() const { 803 return _gens[0]->top_addr(); 804 } 805 806 HeapWord** GenCollectedHeap::end_addr() const { 807 return _gens[0]->end_addr(); 808 } 809 810 size_t GenCollectedHeap::unsafe_max_alloc() { 811 return _gens[0]->unsafe_max_alloc_nogc(); 812 } 813 814 // public collection interfaces 815 816 void GenCollectedHeap::collect(GCCause::Cause cause) { 817 if (should_do_concurrent_full_gc(cause)) { 818 #ifndef SERIALGC 819 // mostly concurrent full collection 820 collect_mostly_concurrent(cause); 821 #else // SERIALGC 822 ShouldNotReachHere(); 823 #endif // SERIALGC 824 } else { 825 #ifdef ASSERT 826 if (cause == GCCause::_scavenge_alot) { 827 // minor collection only 828 collect(cause, 0); 829 } else { 830 // Stop-the-world full collection 831 collect(cause, n_gens() - 1); 832 } 833 #else 834 // Stop-the-world full collection 835 collect(cause, n_gens() - 1); 836 #endif 837 } 838 } 839 840 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) { 841 // The caller doesn't have the Heap_lock 842 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); 843 MutexLocker ml(Heap_lock); 844 collect_locked(cause, max_level); 845 } 846 847 // This interface assumes that it's being called by the 848 // vm thread. It collects the heap assuming that the 849 // heap lock is already held and that we are executing in 850 // the context of the vm thread. 851 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) { 852 assert(Thread::current()->is_VM_thread(), "Precondition#1"); 853 assert(Heap_lock->is_locked(), "Precondition#2"); 854 GCCauseSetter gcs(this, cause); 855 switch (cause) { 856 case GCCause::_heap_inspection: 857 case GCCause::_heap_dump: { 858 HandleMark hm; 859 do_full_collection(false, // don't clear all soft refs 860 n_gens() - 1); 861 break; 862 } 863 default: // XXX FIX ME 864 ShouldNotReachHere(); // Unexpected use of this function 865 } 866 } 867 868 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { 869 // The caller has the Heap_lock 870 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); 871 collect_locked(cause, n_gens() - 1); 872 } 873 874 // this is the private collection interface 875 // The Heap_lock is expected to be held on entry. 876 877 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) { 878 if (_preloading_shared_classes) { 879 warning("\nThe permanent generation is not large enough to preload " 880 "requested classes.\nUse -XX:PermSize= to increase the initial " 881 "size of the permanent generation.\n"); 882 vm_exit(2); 883 } 884 // Read the GC count while holding the Heap_lock 885 unsigned int gc_count_before = total_collections(); 886 unsigned int full_gc_count_before = total_full_collections(); 887 { 888 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back 889 VM_GenCollectFull op(gc_count_before, full_gc_count_before, 890 cause, max_level); 891 VMThread::execute(&op); 892 } 893 } 894 895 #ifndef SERIALGC 896 bool GenCollectedHeap::create_cms_collector() { 897 898 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) || 899 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) && 900 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep, 901 "Unexpected generation kinds"); 902 // Skip two header words in the block content verification 903 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) 904 CMSCollector* collector = new CMSCollector( 905 (ConcurrentMarkSweepGeneration*)_gens[1], 906 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(), 907 _rem_set->as_CardTableRS(), 908 (ConcurrentMarkSweepPolicy*) collector_policy()); 909 910 if (collector == NULL || !collector->completed_initialization()) { 911 if (collector) { 912 delete collector; // Be nice in embedded situation 913 } 914 vm_shutdown_during_initialization("Could not create CMS collector"); 915 return false; 916 } 917 return true; // success 918 } 919 920 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { 921 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 922 923 MutexLocker ml(Heap_lock); 924 // Read the GC counts while holding the Heap_lock 925 unsigned int full_gc_count_before = total_full_collections(); 926 unsigned int gc_count_before = total_collections(); 927 { 928 MutexUnlocker mu(Heap_lock); 929 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 930 VMThread::execute(&op); 931 } 932 } 933 #endif // SERIALGC 934 935 936 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, 937 int max_level) { 938 int local_max_level; 939 if (!incremental_collection_will_fail() && 940 gc_cause() == GCCause::_gc_locker) { 941 local_max_level = 0; 942 } else { 943 local_max_level = max_level; 944 } 945 946 do_collection(true /* full */, 947 clear_all_soft_refs /* clear_all_soft_refs */, 948 0 /* size */, 949 false /* is_tlab */, 950 local_max_level /* max_level */); 951 // Hack XXX FIX ME !!! 952 // A scavenge may not have been attempted, or may have 953 // been attempted and failed, because the old gen was too full 954 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker && 955 incremental_collection_will_fail()) { 956 if (PrintGCDetails) { 957 gclog_or_tty->print_cr("GC locker: Trying a full collection " 958 "because scavenge failed"); 959 } 960 // This time allow the old gen to be collected as well 961 do_collection(true /* full */, 962 clear_all_soft_refs /* clear_all_soft_refs */, 963 0 /* size */, 964 false /* is_tlab */, 965 n_gens() - 1 /* max_level */); 966 } 967 } 968 969 // Returns "TRUE" iff "p" points into the allocated area of the heap. 970 bool GenCollectedHeap::is_in(const void* p) const { 971 #ifndef ASSERT 972 guarantee(VerifyBeforeGC || 973 VerifyDuringGC || 974 VerifyBeforeExit || 975 PrintAssembly || 976 tty->count() != 0 || // already printing 977 VerifyAfterGC || 978 VMError::fatal_error_in_progress(), "too expensive"); 979 980 #endif 981 // This might be sped up with a cache of the last generation that 982 // answered yes. 983 for (int i = 0; i < _n_gens; i++) { 984 if (_gens[i]->is_in(p)) return true; 985 } 986 if (_perm_gen->as_gen()->is_in(p)) return true; 987 // Otherwise... 988 return false; 989 } 990 991 // Returns "TRUE" iff "p" points into the allocated area of the heap. 992 bool GenCollectedHeap::is_in_youngest(void* p) { 993 return _gens[0]->is_in(p); 994 } 995 996 void GenCollectedHeap::oop_iterate(OopClosure* cl) { 997 for (int i = 0; i < _n_gens; i++) { 998 _gens[i]->oop_iterate(cl); 999 } 1000 } 1001 1002 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) { 1003 for (int i = 0; i < _n_gens; i++) { 1004 _gens[i]->oop_iterate(mr, cl); 1005 } 1006 } 1007 1008 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { 1009 for (int i = 0; i < _n_gens; i++) { 1010 _gens[i]->object_iterate(cl); 1011 } 1012 perm_gen()->object_iterate(cl); 1013 } 1014 1015 void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) { 1016 for (int i = 0; i < _n_gens; i++) { 1017 _gens[i]->safe_object_iterate(cl); 1018 } 1019 perm_gen()->safe_object_iterate(cl); 1020 } 1021 1022 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) { 1023 for (int i = 0; i < _n_gens; i++) { 1024 _gens[i]->object_iterate_since_last_GC(cl); 1025 } 1026 } 1027 1028 Space* GenCollectedHeap::space_containing(const void* addr) const { 1029 for (int i = 0; i < _n_gens; i++) { 1030 Space* res = _gens[i]->space_containing(addr); 1031 if (res != NULL) return res; 1032 } 1033 Space* res = perm_gen()->space_containing(addr); 1034 if (res != NULL) return res; 1035 // Otherwise... 1036 assert(false, "Could not find containing space"); 1037 return NULL; 1038 } 1039 1040 1041 HeapWord* GenCollectedHeap::block_start(const void* addr) const { 1042 assert(is_in_reserved(addr), "block_start of address outside of heap"); 1043 for (int i = 0; i < _n_gens; i++) { 1044 if (_gens[i]->is_in_reserved(addr)) { 1045 assert(_gens[i]->is_in(addr), 1046 "addr should be in allocated part of generation"); 1047 return _gens[i]->block_start(addr); 1048 } 1049 } 1050 if (perm_gen()->is_in_reserved(addr)) { 1051 assert(perm_gen()->is_in(addr), 1052 "addr should be in allocated part of perm gen"); 1053 return perm_gen()->block_start(addr); 1054 } 1055 assert(false, "Some generation should contain the address"); 1056 return NULL; 1057 } 1058 1059 size_t GenCollectedHeap::block_size(const HeapWord* addr) const { 1060 assert(is_in_reserved(addr), "block_size of address outside of heap"); 1061 for (int i = 0; i < _n_gens; i++) { 1062 if (_gens[i]->is_in_reserved(addr)) { 1063 assert(_gens[i]->is_in(addr), 1064 "addr should be in allocated part of generation"); 1065 return _gens[i]->block_size(addr); 1066 } 1067 } 1068 if (perm_gen()->is_in_reserved(addr)) { 1069 assert(perm_gen()->is_in(addr), 1070 "addr should be in allocated part of perm gen"); 1071 return perm_gen()->block_size(addr); 1072 } 1073 assert(false, "Some generation should contain the address"); 1074 return 0; 1075 } 1076 1077 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { 1078 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); 1079 assert(block_start(addr) == addr, "addr must be a block start"); 1080 for (int i = 0; i < _n_gens; i++) { 1081 if (_gens[i]->is_in_reserved(addr)) { 1082 return _gens[i]->block_is_obj(addr); 1083 } 1084 } 1085 if (perm_gen()->is_in_reserved(addr)) { 1086 return perm_gen()->block_is_obj(addr); 1087 } 1088 assert(false, "Some generation should contain the address"); 1089 return false; 1090 } 1091 1092 bool GenCollectedHeap::supports_tlab_allocation() const { 1093 for (int i = 0; i < _n_gens; i += 1) { 1094 if (_gens[i]->supports_tlab_allocation()) { 1095 return true; 1096 } 1097 } 1098 return false; 1099 } 1100 1101 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { 1102 size_t result = 0; 1103 for (int i = 0; i < _n_gens; i += 1) { 1104 if (_gens[i]->supports_tlab_allocation()) { 1105 result += _gens[i]->tlab_capacity(); 1106 } 1107 } 1108 return result; 1109 } 1110 1111 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { 1112 size_t result = 0; 1113 for (int i = 0; i < _n_gens; i += 1) { 1114 if (_gens[i]->supports_tlab_allocation()) { 1115 result += _gens[i]->unsafe_max_tlab_alloc(); 1116 } 1117 } 1118 return result; 1119 } 1120 1121 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { 1122 bool gc_overhead_limit_was_exceeded; 1123 HeapWord* result = mem_allocate(size /* size */, 1124 false /* is_large_noref */, 1125 true /* is_tlab */, 1126 &gc_overhead_limit_was_exceeded); 1127 return result; 1128 } 1129 1130 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size 1131 // from the list headed by "*prev_ptr". 1132 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { 1133 bool first = true; 1134 size_t min_size = 0; // "first" makes this conceptually infinite. 1135 ScratchBlock **smallest_ptr, *smallest; 1136 ScratchBlock *cur = *prev_ptr; 1137 while (cur) { 1138 assert(*prev_ptr == cur, "just checking"); 1139 if (first || cur->num_words < min_size) { 1140 smallest_ptr = prev_ptr; 1141 smallest = cur; 1142 min_size = smallest->num_words; 1143 first = false; 1144 } 1145 prev_ptr = &cur->next; 1146 cur = cur->next; 1147 } 1148 smallest = *smallest_ptr; 1149 *smallest_ptr = smallest->next; 1150 return smallest; 1151 } 1152 1153 // Sort the scratch block list headed by res into decreasing size order, 1154 // and set "res" to the result. 1155 static void sort_scratch_list(ScratchBlock*& list) { 1156 ScratchBlock* sorted = NULL; 1157 ScratchBlock* unsorted = list; 1158 while (unsorted) { 1159 ScratchBlock *smallest = removeSmallestScratch(&unsorted); 1160 smallest->next = sorted; 1161 sorted = smallest; 1162 } 1163 list = sorted; 1164 } 1165 1166 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, 1167 size_t max_alloc_words) { 1168 ScratchBlock* res = NULL; 1169 for (int i = 0; i < _n_gens; i++) { 1170 _gens[i]->contribute_scratch(res, requestor, max_alloc_words); 1171 } 1172 sort_scratch_list(res); 1173 return res; 1174 } 1175 1176 void GenCollectedHeap::release_scratch() { 1177 for (int i = 0; i < _n_gens; i++) { 1178 _gens[i]->reset_scratch(); 1179 } 1180 } 1181 1182 size_t GenCollectedHeap::large_typearray_limit() { 1183 return gen_policy()->large_typearray_limit(); 1184 } 1185 1186 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { 1187 void do_generation(Generation* gen) { 1188 gen->prepare_for_verify(); 1189 } 1190 }; 1191 1192 void GenCollectedHeap::prepare_for_verify() { 1193 ensure_parsability(false); // no need to retire TLABs 1194 GenPrepareForVerifyClosure blk; 1195 generation_iterate(&blk, false); 1196 perm_gen()->prepare_for_verify(); 1197 } 1198 1199 1200 void GenCollectedHeap::generation_iterate(GenClosure* cl, 1201 bool old_to_young) { 1202 if (old_to_young) { 1203 for (int i = _n_gens-1; i >= 0; i--) { 1204 cl->do_generation(_gens[i]); 1205 } 1206 } else { 1207 for (int i = 0; i < _n_gens; i++) { 1208 cl->do_generation(_gens[i]); 1209 } 1210 } 1211 } 1212 1213 void GenCollectedHeap::space_iterate(SpaceClosure* cl) { 1214 for (int i = 0; i < _n_gens; i++) { 1215 _gens[i]->space_iterate(cl, true); 1216 } 1217 perm_gen()->space_iterate(cl, true); 1218 } 1219 1220 bool GenCollectedHeap::is_maximal_no_gc() const { 1221 for (int i = 0; i < _n_gens; i++) { // skip perm gen 1222 if (!_gens[i]->is_maximal_no_gc()) { 1223 return false; 1224 } 1225 } 1226 return true; 1227 } 1228 1229 void GenCollectedHeap::save_marks() { 1230 for (int i = 0; i < _n_gens; i++) { 1231 _gens[i]->save_marks(); 1232 } 1233 perm_gen()->save_marks(); 1234 } 1235 1236 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) { 1237 for (int i = 0; i <= collectedGen; i++) { 1238 _gens[i]->compute_new_size(); 1239 } 1240 } 1241 1242 GenCollectedHeap* GenCollectedHeap::heap() { 1243 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()"); 1244 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap"); 1245 return _gch; 1246 } 1247 1248 1249 void GenCollectedHeap::prepare_for_compaction() { 1250 Generation* scanning_gen = _gens[_n_gens-1]; 1251 // Start by compacting into same gen. 1252 CompactPoint cp(scanning_gen, NULL, NULL); 1253 while (scanning_gen != NULL) { 1254 scanning_gen->prepare_for_compaction(&cp); 1255 scanning_gen = prev_gen(scanning_gen); 1256 } 1257 } 1258 1259 GCStats* GenCollectedHeap::gc_stats(int level) const { 1260 return _gens[level]->gc_stats(); 1261 } 1262 1263 void GenCollectedHeap::verify(bool allow_dirty, bool silent, bool option /* ignored */) { 1264 if (!silent) { 1265 gclog_or_tty->print("permgen "); 1266 } 1267 perm_gen()->verify(allow_dirty); 1268 for (int i = _n_gens-1; i >= 0; i--) { 1269 Generation* g = _gens[i]; 1270 if (!silent) { 1271 gclog_or_tty->print(g->name()); 1272 gclog_or_tty->print(" "); 1273 } 1274 g->verify(allow_dirty); 1275 } 1276 if (!silent) { 1277 gclog_or_tty->print("remset "); 1278 } 1279 rem_set()->verify(); 1280 if (!silent) { 1281 gclog_or_tty->print("ref_proc "); 1282 } 1283 ReferenceProcessor::verify(); 1284 } 1285 1286 void GenCollectedHeap::print() const { print_on(tty); } 1287 void GenCollectedHeap::print_on(outputStream* st) const { 1288 for (int i = 0; i < _n_gens; i++) { 1289 _gens[i]->print_on(st); 1290 } 1291 perm_gen()->print_on(st); 1292 } 1293 1294 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { 1295 if (workers() != NULL) { 1296 workers()->threads_do(tc); 1297 } 1298 #ifndef SERIALGC 1299 if (UseConcMarkSweepGC) { 1300 ConcurrentMarkSweepThread::threads_do(tc); 1301 } 1302 #endif // SERIALGC 1303 } 1304 1305 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { 1306 #ifndef SERIALGC 1307 if (UseParNewGC) { 1308 workers()->print_worker_threads_on(st); 1309 } 1310 if (UseConcMarkSweepGC) { 1311 ConcurrentMarkSweepThread::print_all_on(st); 1312 } 1313 #endif // SERIALGC 1314 } 1315 1316 void GenCollectedHeap::print_tracing_info() const { 1317 if (TraceGen0Time) { 1318 get_gen(0)->print_summary_info(); 1319 } 1320 if (TraceGen1Time) { 1321 get_gen(1)->print_summary_info(); 1322 } 1323 } 1324 1325 void GenCollectedHeap::print_heap_change(size_t prev_used) const { 1326 if (PrintGCDetails && Verbose) { 1327 gclog_or_tty->print(" " SIZE_FORMAT 1328 "->" SIZE_FORMAT 1329 "(" SIZE_FORMAT ")", 1330 prev_used, used(), capacity()); 1331 } else { 1332 gclog_or_tty->print(" " SIZE_FORMAT "K" 1333 "->" SIZE_FORMAT "K" 1334 "(" SIZE_FORMAT "K)", 1335 prev_used / K, used() / K, capacity() / K); 1336 } 1337 } 1338 1339 //New method to print perm gen info with PrintGCDetails flag 1340 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const { 1341 gclog_or_tty->print(", [%s :", perm_gen()->short_name()); 1342 perm_gen()->print_heap_change(perm_prev_used); 1343 gclog_or_tty->print("]"); 1344 } 1345 1346 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { 1347 private: 1348 bool _full; 1349 public: 1350 void do_generation(Generation* gen) { 1351 gen->gc_prologue(_full); 1352 } 1353 GenGCPrologueClosure(bool full) : _full(full) {}; 1354 }; 1355 1356 void GenCollectedHeap::gc_prologue(bool full) { 1357 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); 1358 1359 always_do_update_barrier = false; 1360 // Fill TLAB's and such 1361 CollectedHeap::accumulate_statistics_all_tlabs(); 1362 ensure_parsability(true); // retire TLABs 1363 1364 // Call allocation profiler 1365 AllocationProfiler::iterate_since_last_gc(); 1366 // Walk generations 1367 GenGCPrologueClosure blk(full); 1368 generation_iterate(&blk, false); // not old-to-young. 1369 perm_gen()->gc_prologue(full); 1370 }; 1371 1372 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { 1373 private: 1374 bool _full; 1375 public: 1376 void do_generation(Generation* gen) { 1377 gen->gc_epilogue(_full); 1378 } 1379 GenGCEpilogueClosure(bool full) : _full(full) {}; 1380 }; 1381 1382 void GenCollectedHeap::gc_epilogue(bool full) { 1383 // Remember if a partial collection of the heap failed, and 1384 // we did a complete collection. 1385 if (full && incremental_collection_will_fail()) { 1386 set_last_incremental_collection_failed(); 1387 } else { 1388 clear_last_incremental_collection_failed(); 1389 } 1390 // Clear the flag, if set; the generation gc_epilogues will set the 1391 // flag again if the condition persists despite the collection. 1392 clear_incremental_collection_will_fail(); 1393 1394 #ifdef COMPILER2 1395 assert(DerivedPointerTable::is_empty(), "derived pointer present"); 1396 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); 1397 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); 1398 #endif /* COMPILER2 */ 1399 1400 resize_all_tlabs(); 1401 1402 GenGCEpilogueClosure blk(full); 1403 generation_iterate(&blk, false); // not old-to-young. 1404 perm_gen()->gc_epilogue(full); 1405 1406 always_do_update_barrier = UseConcMarkSweepGC; 1407 }; 1408 1409 #ifndef PRODUCT 1410 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { 1411 private: 1412 public: 1413 void do_generation(Generation* gen) { 1414 gen->record_spaces_top(); 1415 } 1416 }; 1417 1418 void GenCollectedHeap::record_gen_tops_before_GC() { 1419 if (ZapUnusedHeapArea) { 1420 GenGCSaveTopsBeforeGCClosure blk; 1421 generation_iterate(&blk, false); // not old-to-young. 1422 perm_gen()->record_spaces_top(); 1423 } 1424 } 1425 #endif // not PRODUCT 1426 1427 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { 1428 public: 1429 void do_generation(Generation* gen) { 1430 gen->ensure_parsability(); 1431 } 1432 }; 1433 1434 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { 1435 CollectedHeap::ensure_parsability(retire_tlabs); 1436 GenEnsureParsabilityClosure ep_cl; 1437 generation_iterate(&ep_cl, false); 1438 perm_gen()->ensure_parsability(); 1439 } 1440 1441 oop GenCollectedHeap::handle_failed_promotion(Generation* gen, 1442 oop obj, 1443 size_t obj_size) { 1444 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 1445 HeapWord* result = NULL; 1446 1447 // First give each higher generation a chance to allocate the promoted object. 1448 Generation* allocator = next_gen(gen); 1449 if (allocator != NULL) { 1450 do { 1451 result = allocator->allocate(obj_size, false); 1452 } while (result == NULL && (allocator = next_gen(allocator)) != NULL); 1453 } 1454 1455 if (result == NULL) { 1456 // Then give gen and higher generations a chance to expand and allocate the 1457 // object. 1458 do { 1459 result = gen->expand_and_allocate(obj_size, false); 1460 } while (result == NULL && (gen = next_gen(gen)) != NULL); 1461 } 1462 1463 if (result != NULL) { 1464 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 1465 } 1466 return oop(result); 1467 } 1468 1469 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { 1470 jlong _time; // in ms 1471 jlong _now; // in ms 1472 1473 public: 1474 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } 1475 1476 jlong time() { return _time; } 1477 1478 void do_generation(Generation* gen) { 1479 _time = MIN2(_time, gen->time_of_last_gc(_now)); 1480 } 1481 }; 1482 1483 jlong GenCollectedHeap::millis_since_last_gc() { 1484 jlong now = os::javaTimeMillis(); 1485 GenTimeOfLastGCClosure tolgc_cl(now); 1486 // iterate over generations getting the oldest 1487 // time that a generation was collected 1488 generation_iterate(&tolgc_cl, false); 1489 tolgc_cl.do_generation(perm_gen()); 1490 // XXX Despite the assert above, since javaTimeMillis() 1491 // doesnot guarantee monotonically increasing return 1492 // values (note, i didn't say "strictly monotonic"), 1493 // we need to guard against getting back a time 1494 // later than now. This should be fixed by basing 1495 // on someting like gethrtime() which guarantees 1496 // monotonicity. Note that cond_wait() is susceptible 1497 // to a similar problem, because its interface is 1498 // based on absolute time in the form of the 1499 // system time's notion of UCT. See also 4506635 1500 // for yet another problem of similar nature. XXX 1501 jlong retVal = now - tolgc_cl.time(); 1502 if (retVal < 0) { 1503 NOT_PRODUCT(warning("time warp: %d", retVal);) 1504 return 0; 1505 } 1506 return retVal; 1507 }