heap.cc revision 85a43c055fcdc366293c61df6f65e586d6967841
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <vector> 24#include <valgrind.h> 25 26#include "base/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/mark_sweep-inl.h" 38#include "gc/collector/partial_mark_sweep.h" 39#include "gc/collector/semi_space.h" 40#include "gc/collector/sticky_mark_sweep.h" 41#include "gc/space/bump_pointer_space.h" 42#include "gc/space/dlmalloc_space-inl.h" 43#include "gc/space/image_space.h" 44#include "gc/space/large_object_space.h" 45#include "gc/space/rosalloc_space-inl.h" 46#include "gc/space/space-inl.h" 47#include "heap-inl.h" 48#include "image.h" 49#include "invoke_arg_array_builder.h" 50#include "mirror/art_field-inl.h" 51#include "mirror/class-inl.h" 52#include "mirror/object.h" 53#include "mirror/object-inl.h" 54#include "mirror/object_array-inl.h" 55#include "object_utils.h" 56#include "os.h" 57#include "runtime.h" 58#include "ScopedLocalRef.h" 59#include "scoped_thread_state_change.h" 60#include "sirt_ref.h" 61#include "thread_list.h" 62#include "UniquePtr.h" 63#include "well_known_classes.h" 64 65namespace art { 66 67extern void SetQuickAllocEntryPointsAllocator(gc::AllocatorType allocator); 68 69namespace gc { 70 71static constexpr bool kGCALotMode = false; 72static constexpr size_t kGcAlotInterval = KB; 73// Minimum amount of remaining bytes before a concurrent GC is triggered. 74static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 75 76Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 77 double target_utilization, size_t capacity, const std::string& image_file_name, 78 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 79 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 80 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 81 bool ignore_max_footprint, bool use_tlab) 82 : non_moving_space_(nullptr), 83 rosalloc_space_(nullptr), 84 dlmalloc_space_(nullptr), 85 concurrent_gc_(false), 86 collector_type_(kCollectorTypeNone), 87 post_zygote_collector_type_(post_zygote_collector_type), 88 background_collector_type_(background_collector_type), 89 parallel_gc_threads_(parallel_gc_threads), 90 conc_gc_threads_(conc_gc_threads), 91 low_memory_mode_(low_memory_mode), 92 long_pause_log_threshold_(long_pause_log_threshold), 93 long_gc_log_threshold_(long_gc_log_threshold), 94 ignore_max_footprint_(ignore_max_footprint), 95 have_zygote_space_(false), 96 soft_reference_queue_(this), 97 weak_reference_queue_(this), 98 finalizer_reference_queue_(this), 99 phantom_reference_queue_(this), 100 cleared_references_(this), 101 is_gc_running_(false), 102 last_gc_type_(collector::kGcTypeNone), 103 next_gc_type_(collector::kGcTypePartial), 104 capacity_(capacity), 105 growth_limit_(growth_limit), 106 max_allowed_footprint_(initial_size), 107 native_footprint_gc_watermark_(initial_size), 108 native_footprint_limit_(2 * initial_size), 109 native_need_to_run_finalization_(false), 110 // Initially assume we perceive jank in case the process state is never updated. 111 process_state_(kProcessStateJankPerceptible), 112 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 113 total_bytes_freed_ever_(0), 114 total_objects_freed_ever_(0), 115 num_bytes_allocated_(0), 116 native_bytes_allocated_(0), 117 gc_memory_overhead_(0), 118 verify_missing_card_marks_(false), 119 verify_system_weaks_(false), 120 verify_pre_gc_heap_(false), 121 verify_post_gc_heap_(false), 122 verify_mod_union_table_(false), 123 min_alloc_space_size_for_sticky_gc_(1112 * MB), 124 min_remaining_space_for_sticky_gc_(1 * MB), 125 last_trim_time_ms_(0), 126 allocation_rate_(0), 127 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 128 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 129 * verification is enabled, we limit the size of allocation stacks to speed up their 130 * searching. 131 */ 132 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 133 : (kDesiredHeapVerification > kVerifyAllFast) ? KB : MB), 134 current_allocator_(kAllocatorTypeDlMalloc), 135 current_non_moving_allocator_(kAllocatorTypeNonMoving), 136 bump_pointer_space_(nullptr), 137 temp_space_(nullptr), 138 reference_referent_offset_(0), 139 reference_queue_offset_(0), 140 reference_queueNext_offset_(0), 141 reference_pendingNext_offset_(0), 142 finalizer_reference_zombie_offset_(0), 143 min_free_(min_free), 144 max_free_(max_free), 145 target_utilization_(target_utilization), 146 total_wait_time_(0), 147 total_allocation_time_(0), 148 verify_object_mode_(kHeapVerificationNotPermitted), 149 gc_disable_count_(0), 150 running_on_valgrind_(RUNNING_ON_VALGRIND), 151 use_tlab_(use_tlab) { 152 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 153 LOG(INFO) << "Heap() entering"; 154 } 155 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 156 // entrypoints. 157 if (!Runtime::Current()->IsZygote() || !kMovingCollector) { 158 ChangeCollector(post_zygote_collector_type_); 159 } else { 160 // We are the zygote, use bump pointer allocation + semi space collector. 161 ChangeCollector(kCollectorTypeSS); 162 } 163 164 live_bitmap_.reset(new accounting::HeapBitmap(this)); 165 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 166 // Requested begin for the alloc space, to follow the mapped image and oat files 167 byte* requested_alloc_space_begin = nullptr; 168 if (!image_file_name.empty()) { 169 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 170 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 171 AddSpace(image_space); 172 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 173 // isn't going to get in the middle 174 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 175 CHECK_GT(oat_file_end_addr, image_space->End()); 176 if (oat_file_end_addr > requested_alloc_space_begin) { 177 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 178 } 179 } 180 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 181 space::MallocSpace* malloc_space; 182 if (kUseRosAlloc) { 183 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 184 requested_alloc_space_begin, low_memory_mode_); 185 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 186 } else { 187 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 188 requested_alloc_space_begin); 189 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 190 } 191 192 if (kMovingCollector) { 193 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 194 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 195 // issues. 196 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 197 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 198 bump_pointer_space_size, nullptr); 199 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 200 AddSpace(bump_pointer_space_); 201 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 202 nullptr); 203 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 204 AddSpace(temp_space_); 205 } 206 non_moving_space_ = malloc_space; 207 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 208 AddSpace(malloc_space); 209 210 // Allocate the large object space. 211 constexpr bool kUseFreeListSpaceForLOS = false; 212 if (kUseFreeListSpaceForLOS) { 213 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 214 } else { 215 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 216 } 217 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 218 AddSpace(large_object_space_); 219 220 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 221 CHECK(!continuous_spaces_.empty()); 222 // Relies on the spaces being sorted. 223 byte* heap_begin = continuous_spaces_.front()->Begin(); 224 byte* heap_end = continuous_spaces_.back()->Limit(); 225 size_t heap_capacity = heap_end - heap_begin; 226 227 // Allocate the card table. 228 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 229 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 230 231 // Card cache for now since it makes it easier for us to update the references to the copying 232 // spaces. 233 accounting::ModUnionTable* mod_union_table = 234 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 235 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 236 AddModUnionTable(mod_union_table); 237 238 // TODO: Count objects in the image space here. 239 num_bytes_allocated_ = 0; 240 241 // Default mark stack size in bytes. 242 static const size_t default_mark_stack_size = 64 * KB; 243 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 244 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 245 max_allocation_stack_size_)); 246 live_stack_.reset(accounting::ObjectStack::Create("live stack", 247 max_allocation_stack_size_)); 248 249 // It's still too early to take a lock because there are no threads yet, but we can create locks 250 // now. We don't create it earlier to make it clear that you can't use locks during heap 251 // initialization. 252 gc_complete_lock_ = new Mutex("GC complete lock"); 253 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 254 *gc_complete_lock_)); 255 last_gc_time_ns_ = NanoTime(); 256 last_gc_size_ = GetBytesAllocated(); 257 258 if (ignore_max_footprint_) { 259 SetIdealFootprint(std::numeric_limits<size_t>::max()); 260 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 261 } 262 CHECK_NE(max_allowed_footprint_, 0U); 263 264 // Create our garbage collectors. 265 for (size_t i = 0; i < 2; ++i) { 266 const bool concurrent = i != 0; 267 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 268 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 269 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 270 } 271 if (kMovingCollector) { 272 // TODO: Clean this up. 273 semi_space_collector_ = new collector::SemiSpace(this); 274 garbage_collectors_.push_back(semi_space_collector_); 275 } 276 277 if (running_on_valgrind_) { 278 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 279 } 280 281 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 282 LOG(INFO) << "Heap() exiting"; 283 } 284} 285 286void Heap::ChangeAllocator(AllocatorType allocator) { 287 // These two allocators are only used internally and don't have any entrypoints. 288 DCHECK_NE(allocator, kAllocatorTypeLOS); 289 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 290 if (current_allocator_ != allocator) { 291 current_allocator_ = allocator; 292 SetQuickAllocEntryPointsAllocator(current_allocator_); 293 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 294 } 295} 296 297bool Heap::IsCompilingBoot() const { 298 for (const auto& space : continuous_spaces_) { 299 if (space->IsImageSpace()) { 300 return false; 301 } else if (space->IsZygoteSpace()) { 302 return false; 303 } 304 } 305 return true; 306} 307 308bool Heap::HasImageSpace() const { 309 for (const auto& space : continuous_spaces_) { 310 if (space->IsImageSpace()) { 311 return true; 312 } 313 } 314 return false; 315} 316 317void Heap::IncrementDisableGC(Thread* self) { 318 // Need to do this holding the lock to prevent races where the GC is about to run / running when 319 // we attempt to disable it. 320 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 321 MutexLock mu(self, *gc_complete_lock_); 322 WaitForGcToCompleteLocked(self); 323 ++gc_disable_count_; 324} 325 326void Heap::DecrementDisableGC(Thread* self) { 327 MutexLock mu(self, *gc_complete_lock_); 328 CHECK_GE(gc_disable_count_, 0U); 329 --gc_disable_count_; 330} 331 332void Heap::UpdateProcessState(ProcessState process_state) { 333 if (process_state_ != process_state) { 334 process_state_ = process_state; 335 if (process_state_ == kProcessStateJankPerceptible) { 336 TransitionCollector(post_zygote_collector_type_); 337 } else { 338 TransitionCollector(background_collector_type_); 339 } 340 } else { 341 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 342 } 343} 344 345void Heap::CreateThreadPool() { 346 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 347 if (num_threads != 0) { 348 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 349 } 350} 351 352void Heap::VisitObjects(ObjectVisitorCallback callback, void* arg) { 353 Thread* self = Thread::Current(); 354 // GCs can move objects, so don't allow this. 355 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 356 if (bump_pointer_space_ != nullptr) { 357 // Visit objects in bump pointer space. 358 bump_pointer_space_->Walk(callback, arg); 359 } 360 // TODO: Switch to standard begin and end to use ranged a based loop. 361 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 362 it < end; ++it) { 363 mirror::Object* obj = *it; 364 callback(obj, arg); 365 } 366 GetLiveBitmap()->Walk(callback, arg); 367 self->EndAssertNoThreadSuspension(old_cause); 368} 369 370void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 371 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 372 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 373 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 374 // TODO: Generalize this to n bitmaps? 375 if (space1 == nullptr) { 376 DCHECK(space2 != nullptr); 377 space1 = space2; 378 } 379 if (space2 == nullptr) { 380 DCHECK(space1 != nullptr); 381 space2 = space1; 382 } 383 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 384 large_object_space_->GetLiveObjects(), stack); 385} 386 387void Heap::DeleteThreadPool() { 388 thread_pool_.reset(nullptr); 389} 390 391void Heap::AddSpace(space::Space* space, bool set_as_default) { 392 DCHECK(space != nullptr); 393 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 394 if (space->IsContinuousSpace()) { 395 DCHECK(!space->IsDiscontinuousSpace()); 396 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 397 // Continuous spaces don't necessarily have bitmaps. 398 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 399 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 400 if (live_bitmap != nullptr) { 401 DCHECK(mark_bitmap != nullptr); 402 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 403 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 404 } 405 continuous_spaces_.push_back(continuous_space); 406 if (set_as_default) { 407 if (continuous_space->IsDlMallocSpace()) { 408 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 409 } else if (continuous_space->IsRosAllocSpace()) { 410 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 411 } 412 } 413 // Ensure that spaces remain sorted in increasing order of start address. 414 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 415 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 416 return a->Begin() < b->Begin(); 417 }); 418 } else { 419 DCHECK(space->IsDiscontinuousSpace()); 420 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 421 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 422 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 423 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 424 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 425 discontinuous_spaces_.push_back(discontinuous_space); 426 } 427 if (space->IsAllocSpace()) { 428 alloc_spaces_.push_back(space->AsAllocSpace()); 429 } 430} 431 432void Heap::RemoveSpace(space::Space* space) { 433 DCHECK(space != nullptr); 434 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 435 if (space->IsContinuousSpace()) { 436 DCHECK(!space->IsDiscontinuousSpace()); 437 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 438 // Continuous spaces don't necessarily have bitmaps. 439 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 440 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 441 if (live_bitmap != nullptr) { 442 DCHECK(mark_bitmap != nullptr); 443 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 444 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 445 } 446 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 447 DCHECK(it != continuous_spaces_.end()); 448 continuous_spaces_.erase(it); 449 if (continuous_space == dlmalloc_space_) { 450 dlmalloc_space_ = nullptr; 451 } else if (continuous_space == rosalloc_space_) { 452 rosalloc_space_ = nullptr; 453 } 454 } else { 455 DCHECK(space->IsDiscontinuousSpace()); 456 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 457 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 458 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 459 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 460 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 461 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 462 discontinuous_space); 463 DCHECK(it != discontinuous_spaces_.end()); 464 discontinuous_spaces_.erase(it); 465 } 466 if (space->IsAllocSpace()) { 467 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 468 DCHECK(it != alloc_spaces_.end()); 469 alloc_spaces_.erase(it); 470 } 471} 472 473void Heap::RegisterGCAllocation(size_t bytes) { 474 if (this != nullptr) { 475 gc_memory_overhead_.FetchAndAdd(bytes); 476 } 477} 478 479void Heap::RegisterGCDeAllocation(size_t bytes) { 480 if (this != nullptr) { 481 gc_memory_overhead_.FetchAndSub(bytes); 482 } 483} 484 485void Heap::DumpGcPerformanceInfo(std::ostream& os) { 486 // Dump cumulative timings. 487 os << "Dumping cumulative Gc timings\n"; 488 uint64_t total_duration = 0; 489 490 // Dump cumulative loggers for each GC type. 491 uint64_t total_paused_time = 0; 492 for (const auto& collector : garbage_collectors_) { 493 CumulativeLogger& logger = collector->GetCumulativeTimings(); 494 if (logger.GetTotalNs() != 0) { 495 os << Dumpable<CumulativeLogger>(logger); 496 const uint64_t total_ns = logger.GetTotalNs(); 497 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 498 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 499 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 500 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 501 Histogram<uint64_t>::CumulativeData cumulative_data; 502 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 503 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 504 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 505 << collector->GetName() << " freed: " << freed_objects 506 << " objects with total size " << PrettySize(freed_bytes) << "\n" 507 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 508 << PrettySize(freed_bytes / seconds) << "/s\n"; 509 total_duration += total_ns; 510 total_paused_time += total_pause_ns; 511 } 512 } 513 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 514 if (total_duration != 0) { 515 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 516 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 517 os << "Mean GC size throughput: " 518 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 519 os << "Mean GC object throughput: " 520 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 521 } 522 size_t total_objects_allocated = GetObjectsAllocatedEver(); 523 os << "Total number of allocations: " << total_objects_allocated << "\n"; 524 size_t total_bytes_allocated = GetBytesAllocatedEver(); 525 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 526 if (kMeasureAllocationTime) { 527 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 528 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 529 << "\n"; 530 } 531 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 532 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 533 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 534} 535 536Heap::~Heap() { 537 VLOG(heap) << "Starting ~Heap()"; 538 STLDeleteElements(&garbage_collectors_); 539 // If we don't reset then the mark stack complains in its destructor. 540 allocation_stack_->Reset(); 541 live_stack_->Reset(); 542 STLDeleteValues(&mod_union_tables_); 543 STLDeleteElements(&continuous_spaces_); 544 STLDeleteElements(&discontinuous_spaces_); 545 delete gc_complete_lock_; 546 VLOG(heap) << "Finished ~Heap()"; 547} 548 549space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 550 bool fail_ok) const { 551 for (const auto& space : continuous_spaces_) { 552 if (space->Contains(obj)) { 553 return space; 554 } 555 } 556 if (!fail_ok) { 557 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 558 } 559 return NULL; 560} 561 562space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 563 bool fail_ok) const { 564 for (const auto& space : discontinuous_spaces_) { 565 if (space->Contains(obj)) { 566 return space; 567 } 568 } 569 if (!fail_ok) { 570 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 571 } 572 return NULL; 573} 574 575space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 576 space::Space* result = FindContinuousSpaceFromObject(obj, true); 577 if (result != NULL) { 578 return result; 579 } 580 return FindDiscontinuousSpaceFromObject(obj, true); 581} 582 583struct SoftReferenceArgs { 584 RootVisitor* is_marked_callback_; 585 RootVisitor* recursive_mark_callback_; 586 void* arg_; 587}; 588 589mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 590 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 591 // TODO: Not preserve all soft references. 592 return args->recursive_mark_callback_(obj, args->arg_); 593} 594 595// Process reference class instances and schedule finalizations. 596void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 597 RootVisitor* is_marked_callback, 598 RootVisitor* recursive_mark_object_callback, void* arg) { 599 // Unless we are in the zygote or required to clear soft references with white references, 600 // preserve some white referents. 601 if (!clear_soft && !Runtime::Current()->IsZygote()) { 602 SoftReferenceArgs soft_reference_args; 603 soft_reference_args.is_marked_callback_ = is_marked_callback; 604 soft_reference_args.recursive_mark_callback_ = recursive_mark_object_callback; 605 soft_reference_args.arg_ = arg; 606 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 607 &soft_reference_args); 608 } 609 timings.StartSplit("ProcessReferences"); 610 // Clear all remaining soft and weak references with white referents. 611 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 612 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 613 timings.EndSplit(); 614 // Preserve all white objects with finalize methods and schedule them for finalization. 615 timings.StartSplit("EnqueueFinalizerReferences"); 616 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 617 recursive_mark_object_callback, arg); 618 timings.EndSplit(); 619 timings.StartSplit("ProcessReferences"); 620 // Clear all f-reachable soft and weak references with white referents. 621 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 622 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 623 // Clear all phantom references with white referents. 624 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 625 // At this point all reference queues other than the cleared references should be empty. 626 DCHECK(soft_reference_queue_.IsEmpty()); 627 DCHECK(weak_reference_queue_.IsEmpty()); 628 DCHECK(finalizer_reference_queue_.IsEmpty()); 629 DCHECK(phantom_reference_queue_.IsEmpty()); 630 timings.EndSplit(); 631} 632 633bool Heap::IsEnqueued(mirror::Object* ref) const { 634 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 635 // will always be non-null. 636 return ref->GetFieldObject<mirror::Object*>(GetReferencePendingNextOffset(), false) != nullptr; 637} 638 639bool Heap::IsEnqueuable(const mirror::Object* ref) const { 640 DCHECK(ref != nullptr); 641 const mirror::Object* queue = 642 ref->GetFieldObject<mirror::Object*>(GetReferenceQueueOffset(), false); 643 const mirror::Object* queue_next = 644 ref->GetFieldObject<mirror::Object*>(GetReferenceQueueNextOffset(), false); 645 return queue != nullptr && queue_next == nullptr; 646} 647 648// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 649// marked, put it on the appropriate list in the heap for later processing. 650void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 651 RootVisitor mark_visitor, void* arg) { 652 DCHECK(klass != nullptr); 653 DCHECK(klass->IsReferenceClass()); 654 DCHECK(obj != nullptr); 655 mirror::Object* referent = GetReferenceReferent(obj); 656 if (referent != nullptr) { 657 mirror::Object* forward_address = mark_visitor(referent, arg); 658 // Null means that the object is not currently marked. 659 if (forward_address == nullptr) { 660 Thread* self = Thread::Current(); 661 // TODO: Remove these locks, and use atomic stacks for storing references? 662 // We need to check that the references haven't already been enqueued since we can end up 663 // scanning the same reference multiple times due to dirty cards. 664 if (klass->IsSoftReferenceClass()) { 665 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 666 } else if (klass->IsWeakReferenceClass()) { 667 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 668 } else if (klass->IsFinalizerReferenceClass()) { 669 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 670 } else if (klass->IsPhantomReferenceClass()) { 671 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 672 } else { 673 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 674 << klass->GetAccessFlags(); 675 } 676 } else if (referent != forward_address) { 677 // Referent is already marked and we need to update it. 678 SetReferenceReferent(obj, forward_address); 679 } 680 } 681} 682 683space::ImageSpace* Heap::GetImageSpace() const { 684 for (const auto& space : continuous_spaces_) { 685 if (space->IsImageSpace()) { 686 return space->AsImageSpace(); 687 } 688 } 689 return NULL; 690} 691 692static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 693 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 694 if (used_bytes < chunk_size) { 695 size_t chunk_free_bytes = chunk_size - used_bytes; 696 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 697 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 698 } 699} 700 701void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 702 std::ostringstream oss; 703 int64_t total_bytes_free = GetFreeMemory(); 704 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 705 << " free bytes"; 706 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 707 if (!large_object_allocation && total_bytes_free >= byte_count) { 708 size_t max_contiguous_allocation = 0; 709 for (const auto& space : continuous_spaces_) { 710 if (space->IsMallocSpace()) { 711 // To allow the Walk/InspectAll() to exclusively-lock the mutator 712 // lock, temporarily release the shared access to the mutator 713 // lock here by transitioning to the suspended state. 714 Locks::mutator_lock_->AssertSharedHeld(self); 715 self->TransitionFromRunnableToSuspended(kSuspended); 716 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 717 self->TransitionFromSuspendedToRunnable(); 718 Locks::mutator_lock_->AssertSharedHeld(self); 719 } 720 } 721 oss << "; failed due to fragmentation (largest possible contiguous allocation " 722 << max_contiguous_allocation << " bytes)"; 723 } 724 self->ThrowOutOfMemoryError(oss.str().c_str()); 725} 726 727void Heap::Trim() { 728 uint64_t start_ns = NanoTime(); 729 // Trim the managed spaces. 730 uint64_t total_alloc_space_allocated = 0; 731 uint64_t total_alloc_space_size = 0; 732 uint64_t managed_reclaimed = 0; 733 for (const auto& space : continuous_spaces_) { 734 if (space->IsMallocSpace() && !space->IsZygoteSpace()) { 735 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 736 total_alloc_space_size += alloc_space->Size(); 737 managed_reclaimed += alloc_space->Trim(); 738 } 739 } 740 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 741 bump_pointer_space_->Size(); 742 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 743 static_cast<float>(total_alloc_space_size); 744 uint64_t gc_heap_end_ns = NanoTime(); 745 // Trim the native heap. 746 dlmalloc_trim(0); 747 size_t native_reclaimed = 0; 748 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 749 uint64_t end_ns = NanoTime(); 750 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 751 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 752 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 753 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 754 << "%."; 755} 756 757bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 758 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 759 // taking the lock. 760 if (obj == nullptr) { 761 return true; 762 } 763 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 764} 765 766bool Heap::IsHeapAddress(const mirror::Object* obj) const { 767 if (kMovingCollector && bump_pointer_space_->HasAddress(obj)) { 768 return true; 769 } 770 // TODO: This probably doesn't work for large objects. 771 return FindSpaceFromObject(obj, true) != nullptr; 772} 773 774bool Heap::IsLiveObjectLocked(const mirror::Object* obj, bool search_allocation_stack, 775 bool search_live_stack, bool sorted) { 776 // Locks::heap_bitmap_lock_->AssertReaderHeld(Thread::Current()); 777 if (obj == nullptr || UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 778 return false; 779 } 780 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 781 space::DiscontinuousSpace* d_space = NULL; 782 if (c_space != NULL) { 783 if (c_space->GetLiveBitmap()->Test(obj)) { 784 return true; 785 } 786 } else if (bump_pointer_space_->Contains(obj) || temp_space_->Contains(obj)) { 787 return true; 788 } else { 789 d_space = FindDiscontinuousSpaceFromObject(obj, true); 790 if (d_space != NULL) { 791 if (d_space->GetLiveObjects()->Test(obj)) { 792 return true; 793 } 794 } 795 } 796 // This is covering the allocation/live stack swapping that is done without mutators suspended. 797 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 798 if (i > 0) { 799 NanoSleep(MsToNs(10)); 800 } 801 if (search_allocation_stack) { 802 if (sorted) { 803 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 804 return true; 805 } 806 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 807 return true; 808 } 809 } 810 811 if (search_live_stack) { 812 if (sorted) { 813 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 814 return true; 815 } 816 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 817 return true; 818 } 819 } 820 } 821 // We need to check the bitmaps again since there is a race where we mark something as live and 822 // then clear the stack containing it. 823 if (c_space != NULL) { 824 if (c_space->GetLiveBitmap()->Test(obj)) { 825 return true; 826 } 827 } else { 828 d_space = FindDiscontinuousSpaceFromObject(obj, true); 829 if (d_space != NULL && d_space->GetLiveObjects()->Test(obj)) { 830 return true; 831 } 832 } 833 return false; 834} 835 836void Heap::VerifyObjectImpl(const mirror::Object* obj) { 837 if (Thread::Current() == NULL || 838 Runtime::Current()->GetThreadList()->GetLockOwner() == Thread::Current()->GetTid()) { 839 return; 840 } 841 VerifyObjectBody(obj); 842} 843 844void Heap::DumpSpaces(std::ostream& stream) { 845 for (const auto& space : continuous_spaces_) { 846 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 847 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 848 stream << space << " " << *space << "\n"; 849 if (live_bitmap != nullptr) { 850 stream << live_bitmap << " " << *live_bitmap << "\n"; 851 } 852 if (mark_bitmap != nullptr) { 853 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 854 } 855 } 856 for (const auto& space : discontinuous_spaces_) { 857 stream << space << " " << *space << "\n"; 858 } 859} 860 861void Heap::VerifyObjectBody(const mirror::Object* obj) { 862 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 863 // Ignore early dawn of the universe verifications. 864 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 865 return; 866 } 867 const byte* raw_addr = reinterpret_cast<const byte*>(obj) + 868 mirror::Object::ClassOffset().Int32Value(); 869 const mirror::Class* c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 870 if (UNLIKELY(c == NULL)) { 871 LOG(FATAL) << "Null class in object: " << obj; 872 } else if (UNLIKELY(!IsAligned<kObjectAlignment>(c))) { 873 LOG(FATAL) << "Class isn't aligned: " << c << " in object: " << obj; 874 } 875 // Check obj.getClass().getClass() == obj.getClass().getClass().getClass() 876 // Note: we don't use the accessors here as they have internal sanity checks 877 // that we don't want to run 878 raw_addr = reinterpret_cast<const byte*>(c) + mirror::Object::ClassOffset().Int32Value(); 879 const mirror::Class* c_c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 880 raw_addr = reinterpret_cast<const byte*>(c_c) + mirror::Object::ClassOffset().Int32Value(); 881 const mirror::Class* c_c_c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 882 CHECK_EQ(c_c, c_c_c); 883 884 if (verify_object_mode_ > kVerifyAllFast) { 885 // TODO: the bitmap tests below are racy if VerifyObjectBody is called without the 886 // heap_bitmap_lock_. 887 if (!IsLiveObjectLocked(obj)) { 888 DumpSpaces(); 889 LOG(FATAL) << "Object is dead: " << obj; 890 } 891 if (!IsLiveObjectLocked(c)) { 892 LOG(FATAL) << "Class of object is dead: " << c << " in object: " << obj; 893 } 894 } 895} 896 897void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 898 DCHECK(obj != NULL); 899 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 900} 901 902void Heap::VerifyHeap() { 903 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 904 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 905} 906 907void Heap::RecordFree(int64_t freed_objects, int64_t freed_bytes) { 908 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 909 num_bytes_allocated_.FetchAndSub(freed_bytes); 910 if (Runtime::Current()->HasStatsEnabled()) { 911 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 912 thread_stats->freed_objects += freed_objects; 913 thread_stats->freed_bytes += freed_bytes; 914 // TODO: Do this concurrently. 915 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 916 global_stats->freed_objects += freed_objects; 917 global_stats->freed_bytes += freed_bytes; 918 } 919} 920 921mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 922 size_t alloc_size, size_t* bytes_allocated, 923 mirror::Class** klass) { 924 mirror::Object* ptr = nullptr; 925 bool was_default_allocator = allocator == GetCurrentAllocator(); 926 DCHECK(klass != nullptr); 927 SirtRef<mirror::Class> sirt_klass(self, *klass); 928 // The allocation failed. If the GC is running, block until it completes, and then retry the 929 // allocation. 930 collector::GcType last_gc = WaitForGcToComplete(self); 931 if (last_gc != collector::kGcTypeNone) { 932 // If we were the default allocator but the allocator changed while we were suspended, 933 // abort the allocation. 934 if (was_default_allocator && allocator != GetCurrentAllocator()) { 935 *klass = sirt_klass.get(); 936 return nullptr; 937 } 938 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 939 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 940 } 941 942 // Loop through our different Gc types and try to Gc until we get enough free memory. 943 for (collector::GcType gc_type : gc_plan_) { 944 if (ptr != nullptr) { 945 break; 946 } 947 // Attempt to run the collector, if we succeed, re-try the allocation. 948 bool gc_ran = 949 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 950 if (was_default_allocator && allocator != GetCurrentAllocator()) { 951 *klass = sirt_klass.get(); 952 return nullptr; 953 } 954 if (gc_ran) { 955 // Did we free sufficient memory for the allocation to succeed? 956 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 957 } 958 } 959 // Allocations have failed after GCs; this is an exceptional state. 960 if (ptr == nullptr) { 961 // Try harder, growing the heap if necessary. 962 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 963 } 964 if (ptr == nullptr) { 965 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 966 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 967 // VM spec requires that all SoftReferences have been collected and cleared before throwing 968 // OOME. 969 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 970 << " allocation"; 971 // TODO: Run finalization, but this may cause more allocations to occur. 972 // We don't need a WaitForGcToComplete here either. 973 DCHECK(!gc_plan_.empty()); 974 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 975 if (was_default_allocator && allocator != GetCurrentAllocator()) { 976 *klass = sirt_klass.get(); 977 return nullptr; 978 } 979 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 980 if (ptr == nullptr) { 981 ThrowOutOfMemoryError(self, alloc_size, false); 982 } 983 } 984 *klass = sirt_klass.get(); 985 return ptr; 986} 987 988void Heap::SetTargetHeapUtilization(float target) { 989 DCHECK_GT(target, 0.0f); // asserted in Java code 990 DCHECK_LT(target, 1.0f); 991 target_utilization_ = target; 992} 993 994size_t Heap::GetObjectsAllocated() const { 995 size_t total = 0; 996 for (space::AllocSpace* space : alloc_spaces_) { 997 total += space->GetObjectsAllocated(); 998 } 999 return total; 1000} 1001 1002size_t Heap::GetObjectsAllocatedEver() const { 1003 return GetObjectsFreedEver() + GetObjectsAllocated(); 1004} 1005 1006size_t Heap::GetBytesAllocatedEver() const { 1007 return GetBytesFreedEver() + GetBytesAllocated(); 1008} 1009 1010class InstanceCounter { 1011 public: 1012 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1013 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1014 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1015 } 1016 1017 void operator()(const mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1018 for (size_t i = 0; i < classes_.size(); ++i) { 1019 const mirror::Class* instance_class = o->GetClass(); 1020 if (use_is_assignable_from_) { 1021 if (instance_class != NULL && classes_[i]->IsAssignableFrom(instance_class)) { 1022 ++counts_[i]; 1023 } 1024 } else { 1025 if (instance_class == classes_[i]) { 1026 ++counts_[i]; 1027 } 1028 } 1029 } 1030 } 1031 1032 private: 1033 const std::vector<mirror::Class*>& classes_; 1034 bool use_is_assignable_from_; 1035 uint64_t* const counts_; 1036 1037 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1038}; 1039 1040void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1041 uint64_t* counts) { 1042 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1043 // is empty, so the live bitmap is the only place we need to look. 1044 Thread* self = Thread::Current(); 1045 self->TransitionFromRunnableToSuspended(kNative); 1046 CollectGarbage(false); 1047 self->TransitionFromSuspendedToRunnable(); 1048 1049 InstanceCounter counter(classes, use_is_assignable_from, counts); 1050 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1051 GetLiveBitmap()->Visit(counter); 1052} 1053 1054class InstanceCollector { 1055 public: 1056 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1057 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1058 : class_(c), max_count_(max_count), instances_(instances) { 1059 } 1060 1061 void operator()(const mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1062 const mirror::Class* instance_class = o->GetClass(); 1063 if (instance_class == class_) { 1064 if (max_count_ == 0 || instances_.size() < max_count_) { 1065 instances_.push_back(const_cast<mirror::Object*>(o)); 1066 } 1067 } 1068 } 1069 1070 private: 1071 mirror::Class* class_; 1072 uint32_t max_count_; 1073 std::vector<mirror::Object*>& instances_; 1074 1075 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1076}; 1077 1078void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1079 std::vector<mirror::Object*>& instances) { 1080 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1081 // is empty, so the live bitmap is the only place we need to look. 1082 Thread* self = Thread::Current(); 1083 self->TransitionFromRunnableToSuspended(kNative); 1084 CollectGarbage(false); 1085 self->TransitionFromSuspendedToRunnable(); 1086 1087 InstanceCollector collector(c, max_count, instances); 1088 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1089 GetLiveBitmap()->Visit(collector); 1090} 1091 1092class ReferringObjectsFinder { 1093 public: 1094 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1095 std::vector<mirror::Object*>& referring_objects) 1096 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1097 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1098 } 1099 1100 // For bitmap Visit. 1101 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1102 // annotalysis on visitors. 1103 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1104 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1105 } 1106 1107 // For MarkSweep::VisitObjectReferences. 1108 void operator()(mirror::Object* referrer, mirror::Object* object, 1109 const MemberOffset&, bool) const { 1110 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1111 referring_objects_.push_back(referrer); 1112 } 1113 } 1114 1115 private: 1116 mirror::Object* object_; 1117 uint32_t max_count_; 1118 std::vector<mirror::Object*>& referring_objects_; 1119 1120 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1121}; 1122 1123void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1124 std::vector<mirror::Object*>& referring_objects) { 1125 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1126 // is empty, so the live bitmap is the only place we need to look. 1127 Thread* self = Thread::Current(); 1128 self->TransitionFromRunnableToSuspended(kNative); 1129 CollectGarbage(false); 1130 self->TransitionFromSuspendedToRunnable(); 1131 1132 ReferringObjectsFinder finder(o, max_count, referring_objects); 1133 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1134 GetLiveBitmap()->Visit(finder); 1135} 1136 1137void Heap::CollectGarbage(bool clear_soft_references) { 1138 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1139 // last GC will not have necessarily been cleared. 1140 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1141} 1142 1143void Heap::TransitionCollector(CollectorType collector_type) { 1144 if (collector_type == collector_type_) { 1145 return; 1146 } 1147 uint64_t start_time = NanoTime(); 1148 int32_t before_size = GetTotalMemory(); 1149 int32_t before_allocated = num_bytes_allocated_.Load(); 1150 ThreadList* tl = Runtime::Current()->GetThreadList(); 1151 Thread* self = Thread::Current(); 1152 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1153 Locks::mutator_lock_->AssertNotHeld(self); 1154 // Busy wait until we can GC (StartGC can fail if we have a non-zero gc_disable_count_, this 1155 // rarely occurs however). 1156 while (!StartGC(self)) { 1157 usleep(100); 1158 } 1159 tl->SuspendAll(); 1160 switch (collector_type) { 1161 case kCollectorTypeSS: { 1162 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1163 space::MallocSpace* main_space; 1164 if (rosalloc_space_ != nullptr) { 1165 DCHECK(kUseRosAlloc); 1166 main_space = rosalloc_space_; 1167 } else { 1168 DCHECK(dlmalloc_space_ != nullptr); 1169 main_space = dlmalloc_space_; 1170 } 1171 Compact(temp_space_, main_space); 1172 DCHECK(allocator_mem_map_.get() == nullptr); 1173 allocator_mem_map_.reset(main_space->ReleaseMemMap()); 1174 madvise(main_space->Begin(), main_space->Size(), MADV_DONTNEED); 1175 RemoveSpace(main_space); 1176 break; 1177 } 1178 case kCollectorTypeMS: 1179 // Fall through. 1180 case kCollectorTypeCMS: { 1181 if (collector_type_ == kCollectorTypeSS) { 1182 // TODO: Use mem-map from temp space? 1183 MemMap* mem_map = allocator_mem_map_.release(); 1184 CHECK(mem_map != nullptr); 1185 size_t initial_size = kDefaultInitialSize; 1186 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1187 space::MallocSpace* malloc_space; 1188 if (kUseRosAlloc) { 1189 malloc_space = 1190 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1191 initial_size, mem_map->Size(), 1192 mem_map->Size(), low_memory_mode_); 1193 } else { 1194 malloc_space = 1195 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1196 initial_size, mem_map->Size(), 1197 mem_map->Size()); 1198 } 1199 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 1200 AddSpace(malloc_space); 1201 Compact(malloc_space, bump_pointer_space_); 1202 } 1203 break; 1204 } 1205 default: { 1206 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1207 break; 1208 } 1209 } 1210 ChangeCollector(collector_type); 1211 tl->ResumeAll(); 1212 // Can't call into java code with all threads suspended. 1213 EnqueueClearedReferences(); 1214 uint64_t duration = NanoTime() - start_time; 1215 GrowForUtilization(collector::kGcTypeFull, duration); 1216 FinishGC(self, collector::kGcTypeFull); 1217 int32_t after_size = GetTotalMemory(); 1218 int32_t delta_size = before_size - after_size; 1219 int32_t after_allocated = num_bytes_allocated_.Load(); 1220 int32_t delta_allocated = before_allocated - after_allocated; 1221 const std::string saved_bytes_str = 1222 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1223 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1224 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1225 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1226 << PrettySize(delta_size) << " saved"; 1227} 1228 1229void Heap::ChangeCollector(CollectorType collector_type) { 1230 // TODO: Only do this with all mutators suspended to avoid races. 1231 if (collector_type != collector_type_) { 1232 collector_type_ = collector_type; 1233 gc_plan_.clear(); 1234 switch (collector_type_) { 1235 case kCollectorTypeSS: { 1236 concurrent_gc_ = false; 1237 gc_plan_.push_back(collector::kGcTypeFull); 1238 if (use_tlab_) { 1239 ChangeAllocator(kAllocatorTypeTLAB); 1240 } else { 1241 ChangeAllocator(kAllocatorTypeBumpPointer); 1242 } 1243 break; 1244 } 1245 case kCollectorTypeMS: { 1246 concurrent_gc_ = false; 1247 gc_plan_.push_back(collector::kGcTypeSticky); 1248 gc_plan_.push_back(collector::kGcTypePartial); 1249 gc_plan_.push_back(collector::kGcTypeFull); 1250 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1251 break; 1252 } 1253 case kCollectorTypeCMS: { 1254 concurrent_gc_ = true; 1255 gc_plan_.push_back(collector::kGcTypeSticky); 1256 gc_plan_.push_back(collector::kGcTypePartial); 1257 gc_plan_.push_back(collector::kGcTypeFull); 1258 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1259 break; 1260 } 1261 default: { 1262 LOG(FATAL) << "Unimplemented"; 1263 } 1264 } 1265 if (concurrent_gc_) { 1266 concurrent_start_bytes_ = 1267 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1268 } else { 1269 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1270 } 1271 } 1272} 1273 1274static void MarkInBitmapCallback(mirror::Object* obj, void* arg) { 1275 reinterpret_cast<accounting::SpaceBitmap*>(arg)->Set(obj); 1276} 1277 1278// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1279class ZygoteCompactingCollector : public collector::SemiSpace { 1280 public: 1281 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector") { 1282 } 1283 1284 void BuildBins(space::ContinuousSpace* space) { 1285 bin_live_bitmap_ = space->GetLiveBitmap(); 1286 bin_mark_bitmap_ = space->GetMarkBitmap(); 1287 BinContext context; 1288 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1289 context.collector_ = this; 1290 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1291 // Note: This requires traversing the space in increasing order of object addresses. 1292 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1293 // Add the last bin which spans after the last object to the end of the space. 1294 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1295 } 1296 1297 private: 1298 struct BinContext { 1299 uintptr_t prev_; // The end of the previous object. 1300 ZygoteCompactingCollector* collector_; 1301 }; 1302 // Maps from bin sizes to locations. 1303 std::multimap<size_t, uintptr_t> bins_; 1304 // Live bitmap of the space which contains the bins. 1305 accounting::SpaceBitmap* bin_live_bitmap_; 1306 // Mark bitmap of the space which contains the bins. 1307 accounting::SpaceBitmap* bin_mark_bitmap_; 1308 1309 static void Callback(mirror::Object* obj, void* arg) 1310 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1311 DCHECK(arg != nullptr); 1312 BinContext* context = reinterpret_cast<BinContext*>(arg); 1313 ZygoteCompactingCollector* collector = context->collector_; 1314 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1315 size_t bin_size = object_addr - context->prev_; 1316 // Add the bin consisting of the end of the previous object to the start of the current object. 1317 collector->AddBin(bin_size, context->prev_); 1318 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1319 } 1320 1321 void AddBin(size_t size, uintptr_t position) { 1322 if (size != 0) { 1323 bins_.insert(std::make_pair(size, position)); 1324 } 1325 } 1326 1327 virtual bool ShouldSweepSpace(space::MallocSpace* space) const { 1328 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1329 // allocator. 1330 return false; 1331 } 1332 1333 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1334 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1335 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1336 mirror::Object* forward_address = nullptr; 1337 // Find the smallest bin which we can move obj in. 1338 auto it = bins_.lower_bound(object_size); 1339 if (it == bins_.end()) { 1340 // No available space in the bins, place it in the target space instead (grows the zygote 1341 // space). 1342 size_t bytes_allocated = 0; 1343 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated); 1344 if (to_space_live_bitmap_ != nullptr) { 1345 to_space_live_bitmap_->Set(forward_address); 1346 } 1347 } else { 1348 size_t size = it->first; 1349 uintptr_t pos = it->second; 1350 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1351 forward_address = reinterpret_cast<mirror::Object*>(pos); 1352 // Set the live and mark bits so that sweeping system weaks works properly. 1353 bin_live_bitmap_->Set(forward_address); 1354 bin_mark_bitmap_->Set(forward_address); 1355 DCHECK_GE(size, object_size); 1356 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1357 } 1358 // Copy the object over to its new location. 1359 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1360 return forward_address; 1361 } 1362}; 1363 1364void Heap::PreZygoteFork() { 1365 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1366 Thread* self = Thread::Current(); 1367 MutexLock mu(self, zygote_creation_lock_); 1368 // Try to see if we have any Zygote spaces. 1369 if (have_zygote_space_) { 1370 return; 1371 } 1372 VLOG(heap) << "Starting PreZygoteFork"; 1373 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1374 // Trim the pages at the end of the non moving space. 1375 non_moving_space_->Trim(); 1376 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1377 // Change the collector to the post zygote one. 1378 ChangeCollector(post_zygote_collector_type_); 1379 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1380 if (semi_space_collector_ != nullptr) { 1381 ZygoteCompactingCollector zygote_collector(this); 1382 zygote_collector.BuildBins(non_moving_space_); 1383 // Create a new bump pointer space which we will compact into. 1384 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1385 non_moving_space_->Limit()); 1386 // Compact the bump pointer space to a new zygote bump pointer space. 1387 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1388 zygote_collector.SetFromSpace(bump_pointer_space_); 1389 zygote_collector.SetToSpace(&target_space); 1390 zygote_collector.Run(false); 1391 CHECK(temp_space_->IsEmpty()); 1392 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1393 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1394 // Update the end and write out image. 1395 non_moving_space_->SetEnd(target_space.End()); 1396 non_moving_space_->SetLimit(target_space.Limit()); 1397 accounting::SpaceBitmap* bitmap = non_moving_space_->GetLiveBitmap(); 1398 // Record the allocations in the bitmap. 1399 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1400 target_space.Walk(MarkInBitmapCallback, bitmap); 1401 } 1402 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1403 // the remaining available heap memory. 1404 space::MallocSpace* zygote_space = non_moving_space_; 1405 non_moving_space_ = non_moving_space_->CreateZygoteSpace("alloc space", low_memory_mode_); 1406 if (non_moving_space_->IsRosAllocSpace()) { 1407 rosalloc_space_ = non_moving_space_->AsRosAllocSpace(); 1408 } else if (non_moving_space_->IsDlMallocSpace()) { 1409 dlmalloc_space_ = non_moving_space_->AsDlMallocSpace(); 1410 } 1411 // Can't use RosAlloc for non moving space due to thread local buffers. 1412 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1413 // Change the GC retention policy of the zygote space to only collect when full. 1414 zygote_space->SetGcRetentionPolicy(space::kGcRetentionPolicyFullCollect); 1415 AddSpace(non_moving_space_); 1416 have_zygote_space_ = true; 1417 zygote_space->InvalidateAllocator(); 1418 // Create the zygote space mod union table. 1419 accounting::ModUnionTable* mod_union_table = 1420 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1421 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1422 AddModUnionTable(mod_union_table); 1423 // Reset the cumulative loggers since we now have a few additional timing phases. 1424 for (const auto& collector : garbage_collectors_) { 1425 collector->ResetCumulativeStatistics(); 1426 } 1427 // TODO: Not limited space for non-movable objects? 1428 space::MallocSpace* new_non_moving_space 1429 = space::DlMallocSpace::Create("Non moving dlmalloc space", 2 * MB, 64 * MB, 64 * MB, 1430 nullptr); 1431 AddSpace(new_non_moving_space, false); 1432 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1433 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1434 non_moving_space_ = new_non_moving_space; 1435} 1436 1437void Heap::FlushAllocStack() { 1438 MarkAllocStackAsLive(allocation_stack_.get()); 1439 allocation_stack_->Reset(); 1440} 1441 1442void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1443 accounting::SpaceBitmap* bitmap2, 1444 accounting::SpaceSetMap* large_objects, 1445 accounting::ObjectStack* stack) { 1446 DCHECK(bitmap1 != nullptr); 1447 DCHECK(bitmap2 != nullptr); 1448 mirror::Object** limit = stack->End(); 1449 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1450 const mirror::Object* obj = *it; 1451 DCHECK(obj != nullptr); 1452 if (bitmap1->HasAddress(obj)) { 1453 bitmap1->Set(obj); 1454 } else if (bitmap2->HasAddress(obj)) { 1455 bitmap2->Set(obj); 1456 } else { 1457 large_objects->Set(obj); 1458 } 1459 } 1460} 1461 1462const char* PrettyCause(GcCause cause) { 1463 switch (cause) { 1464 case kGcCauseForAlloc: return "Alloc"; 1465 case kGcCauseBackground: return "Background"; 1466 case kGcCauseExplicit: return "Explicit"; 1467 default: 1468 LOG(FATAL) << "Unreachable"; 1469 } 1470 return ""; 1471} 1472 1473void Heap::SwapSemiSpaces() { 1474 // Swap the spaces so we allocate into the space which we just evacuated. 1475 std::swap(bump_pointer_space_, temp_space_); 1476} 1477 1478void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1479 space::ContinuousMemMapAllocSpace* source_space) { 1480 CHECK(kMovingCollector); 1481 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1482 if (target_space != source_space) { 1483 semi_space_collector_->SetFromSpace(source_space); 1484 semi_space_collector_->SetToSpace(target_space); 1485 semi_space_collector_->Run(false); 1486 } 1487} 1488 1489collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1490 bool clear_soft_references) { 1491 Thread* self = Thread::Current(); 1492 Runtime* runtime = Runtime::Current(); 1493 // If the heap can't run the GC, silently fail and return that no GC was run. 1494 switch (gc_type) { 1495 case collector::kGcTypePartial: { 1496 if (!have_zygote_space_) { 1497 return collector::kGcTypeNone; 1498 } 1499 break; 1500 } 1501 default: { 1502 // Other GC types don't have any special cases which makes them not runnable. The main case 1503 // here is full GC. 1504 } 1505 } 1506 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1507 Locks::mutator_lock_->AssertNotHeld(self); 1508 if (self->IsHandlingStackOverflow()) { 1509 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1510 } 1511 gc_complete_lock_->AssertNotHeld(self); 1512 if (!StartGC(self)) { 1513 return collector::kGcTypeNone; 1514 } 1515 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1516 ++runtime->GetStats()->gc_for_alloc_count; 1517 ++self->GetStats()->gc_for_alloc_count; 1518 } 1519 uint64_t gc_start_time_ns = NanoTime(); 1520 uint64_t gc_start_size = GetBytesAllocated(); 1521 // Approximate allocation rate in bytes / second. 1522 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1523 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1524 if (LIKELY(ms_delta != 0)) { 1525 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1526 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1527 } 1528 1529 DCHECK_LT(gc_type, collector::kGcTypeMax); 1530 DCHECK_NE(gc_type, collector::kGcTypeNone); 1531 1532 collector::GarbageCollector* collector = nullptr; 1533 // TODO: Clean this up. 1534 if (collector_type_ == kCollectorTypeSS) { 1535 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1536 current_allocator_ == kAllocatorTypeTLAB); 1537 gc_type = semi_space_collector_->GetGcType(); 1538 CHECK(temp_space_->IsEmpty()); 1539 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1540 semi_space_collector_->SetToSpace(temp_space_); 1541 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1542 collector = semi_space_collector_; 1543 gc_type = collector::kGcTypeFull; 1544 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1545 current_allocator_ == kAllocatorTypeDlMalloc) { 1546 for (const auto& cur_collector : garbage_collectors_) { 1547 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1548 cur_collector->GetGcType() == gc_type) { 1549 collector = cur_collector; 1550 break; 1551 } 1552 } 1553 } else { 1554 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1555 } 1556 CHECK(collector != nullptr) 1557 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1558 << " and type=" << gc_type; 1559 1560 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1561 1562 collector->Run(clear_soft_references); 1563 total_objects_freed_ever_ += collector->GetFreedObjects(); 1564 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1565 1566 // Enqueue cleared references. 1567 Locks::mutator_lock_->AssertNotHeld(self); 1568 EnqueueClearedReferences(); 1569 1570 // Grow the heap so that we know when to perform the next GC. 1571 GrowForUtilization(gc_type, collector->GetDurationNs()); 1572 1573 if (CareAboutPauseTimes()) { 1574 const size_t duration = collector->GetDurationNs(); 1575 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1576 // GC for alloc pauses the allocating thread, so consider it as a pause. 1577 bool was_slow = duration > long_gc_log_threshold_ || 1578 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1579 if (!was_slow) { 1580 for (uint64_t pause : pauses) { 1581 was_slow = was_slow || pause > long_pause_log_threshold_; 1582 } 1583 } 1584 if (was_slow) { 1585 const size_t percent_free = GetPercentFree(); 1586 const size_t current_heap_size = GetBytesAllocated(); 1587 const size_t total_memory = GetTotalMemory(); 1588 std::ostringstream pause_string; 1589 for (size_t i = 0; i < pauses.size(); ++i) { 1590 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1591 << ((i != pauses.size() - 1) ? ", " : ""); 1592 } 1593 LOG(INFO) << gc_cause << " " << collector->GetName() 1594 << " GC freed " << collector->GetFreedObjects() << "(" 1595 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1596 << collector->GetFreedLargeObjects() << "(" 1597 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1598 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1599 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1600 << " total " << PrettyDuration((duration / 1000) * 1000); 1601 if (VLOG_IS_ON(heap)) { 1602 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1603 } 1604 } 1605 } 1606 FinishGC(self, gc_type); 1607 ATRACE_END(); 1608 1609 // Inform DDMS that a GC completed. 1610 Dbg::GcDidFinish(); 1611 return gc_type; 1612} 1613 1614bool Heap::StartGC(Thread* self) { 1615 MutexLock mu(self, *gc_complete_lock_); 1616 // Ensure there is only one GC at a time. 1617 WaitForGcToCompleteLocked(self); 1618 // TODO: if another thread beat this one to do the GC, perhaps we should just return here? 1619 // Not doing at the moment to ensure soft references are cleared. 1620 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1621 if (gc_disable_count_ != 0) { 1622 LOG(WARNING) << "Skipping GC due to disable count " << gc_disable_count_; 1623 return false; 1624 } 1625 is_gc_running_ = true; 1626 return true; 1627} 1628 1629void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1630 MutexLock mu(self, *gc_complete_lock_); 1631 is_gc_running_ = false; 1632 last_gc_type_ = gc_type; 1633 // Wake anyone who may have been waiting for the GC to complete. 1634 gc_complete_cond_->Broadcast(self); 1635} 1636 1637static mirror::Object* RootMatchesObjectVisitor(mirror::Object* root, void* arg) { 1638 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1639 if (root == obj) { 1640 LOG(INFO) << "Object " << obj << " is a root"; 1641 } 1642 return root; 1643} 1644 1645class ScanVisitor { 1646 public: 1647 void operator()(const mirror::Object* obj) const { 1648 LOG(ERROR) << "Would have rescanned object " << obj; 1649 } 1650}; 1651 1652// Verify a reference from an object. 1653class VerifyReferenceVisitor { 1654 public: 1655 explicit VerifyReferenceVisitor(Heap* heap) 1656 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1657 : heap_(heap), failed_(false) {} 1658 1659 bool Failed() const { 1660 return failed_; 1661 } 1662 1663 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1664 // analysis on visitors. 1665 void operator()(const mirror::Object* obj, const mirror::Object* ref, 1666 const MemberOffset& offset, bool /* is_static */) const 1667 NO_THREAD_SAFETY_ANALYSIS { 1668 // Verify that the reference is live. 1669 if (UNLIKELY(ref != NULL && !IsLive(ref))) { 1670 accounting::CardTable* card_table = heap_->GetCardTable(); 1671 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1672 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1673 if (!failed_) { 1674 // Print message on only on first failure to prevent spam. 1675 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1676 failed_ = true; 1677 } 1678 if (obj != nullptr) { 1679 byte* card_addr = card_table->CardFromAddr(obj); 1680 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1681 << offset << "\n card value = " << static_cast<int>(*card_addr); 1682 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1683 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1684 } else { 1685 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1686 } 1687 1688 // Attmept to find the class inside of the recently freed objects. 1689 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1690 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1691 space::MallocSpace* space = ref_space->AsMallocSpace(); 1692 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1693 if (ref_class != nullptr) { 1694 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1695 << PrettyClass(ref_class); 1696 } else { 1697 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1698 } 1699 } 1700 1701 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1702 ref->GetClass()->IsClass()) { 1703 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1704 } else { 1705 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1706 << ") is not a valid heap address"; 1707 } 1708 1709 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1710 void* cover_begin = card_table->AddrFromCard(card_addr); 1711 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1712 accounting::CardTable::kCardSize); 1713 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1714 << "-" << cover_end; 1715 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1716 1717 // Print out how the object is live. 1718 if (bitmap != NULL && bitmap->Test(obj)) { 1719 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1720 } 1721 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1722 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1723 } 1724 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1725 LOG(ERROR) << "Object " << obj << " found in live stack"; 1726 } 1727 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1728 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1729 } 1730 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1731 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1732 } 1733 // Attempt to see if the card table missed the reference. 1734 ScanVisitor scan_visitor; 1735 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1736 card_table->Scan(bitmap, byte_cover_begin, 1737 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1738 1739 // Search to see if any of the roots reference our object. 1740 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1741 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1742 1743 // Search to see if any of the roots reference our reference. 1744 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1745 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1746 } else { 1747 LOG(ERROR) << "Root references dead object " << ref << "\nRef type " << PrettyTypeOf(ref); 1748 } 1749 } 1750 } 1751 1752 bool IsLive(const mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1753 return heap_->IsLiveObjectLocked(obj, true, false, true); 1754 } 1755 1756 static mirror::Object* VerifyRoots(mirror::Object* root, void* arg) { 1757 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1758 (*visitor)(nullptr, root, MemberOffset(0), true); 1759 return root; 1760 } 1761 1762 private: 1763 Heap* const heap_; 1764 mutable bool failed_; 1765}; 1766 1767// Verify all references within an object, for use with HeapBitmap::Visit. 1768class VerifyObjectVisitor { 1769 public: 1770 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1771 1772 void operator()(mirror::Object* obj) const 1773 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1774 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1775 // be live or else how did we find it in the live bitmap? 1776 VerifyReferenceVisitor visitor(heap_); 1777 // The class doesn't count as a reference but we should verify it anyways. 1778 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1779 if (obj->GetClass()->IsReferenceClass()) { 1780 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1781 } 1782 failed_ = failed_ || visitor.Failed(); 1783 } 1784 1785 static void VisitCallback(mirror::Object* obj, void* arg) 1786 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1787 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1788 visitor->operator()(obj); 1789 } 1790 1791 bool Failed() const { 1792 return failed_; 1793 } 1794 1795 private: 1796 Heap* const heap_; 1797 mutable bool failed_; 1798}; 1799 1800// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1801bool Heap::VerifyHeapReferences() { 1802 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1803 // Lets sort our allocation stacks so that we can efficiently binary search them. 1804 allocation_stack_->Sort(); 1805 live_stack_->Sort(); 1806 VerifyObjectVisitor visitor(this); 1807 // Verify objects in the allocation stack since these will be objects which were: 1808 // 1. Allocated prior to the GC (pre GC verification). 1809 // 2. Allocated during the GC (pre sweep GC verification). 1810 // We don't want to verify the objects in the live stack since they themselves may be 1811 // pointing to dead objects if they are not reachable. 1812 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1813 // Verify the roots: 1814 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1815 if (visitor.Failed()) { 1816 // Dump mod-union tables. 1817 for (const auto& table_pair : mod_union_tables_) { 1818 accounting::ModUnionTable* mod_union_table = table_pair.second; 1819 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1820 } 1821 DumpSpaces(); 1822 return false; 1823 } 1824 return true; 1825} 1826 1827class VerifyReferenceCardVisitor { 1828 public: 1829 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1830 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1831 Locks::heap_bitmap_lock_) 1832 : heap_(heap), failed_(failed) { 1833 } 1834 1835 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1836 // annotalysis on visitors. 1837 void operator()(const mirror::Object* obj, const mirror::Object* ref, const MemberOffset& offset, 1838 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1839 // Filter out class references since changing an object's class does not mark the card as dirty. 1840 // Also handles large objects, since the only reference they hold is a class reference. 1841 if (ref != NULL && !ref->IsClass()) { 1842 accounting::CardTable* card_table = heap_->GetCardTable(); 1843 // If the object is not dirty and it is referencing something in the live stack other than 1844 // class, then it must be on a dirty card. 1845 if (!card_table->AddrIsInCardTable(obj)) { 1846 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1847 *failed_ = true; 1848 } else if (!card_table->IsDirty(obj)) { 1849 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1850 // kCardDirty - 1 if it didnt get touched since we aged it. 1851 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1852 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1853 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1854 LOG(ERROR) << "Object " << obj << " found in live stack"; 1855 } 1856 if (heap_->GetLiveBitmap()->Test(obj)) { 1857 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1858 } 1859 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1860 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1861 1862 // Print which field of the object is dead. 1863 if (!obj->IsObjectArray()) { 1864 const mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1865 CHECK(klass != NULL); 1866 const mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1867 : klass->GetIFields(); 1868 CHECK(fields != NULL); 1869 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1870 const mirror::ArtField* cur = fields->Get(i); 1871 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1872 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1873 << PrettyField(cur); 1874 break; 1875 } 1876 } 1877 } else { 1878 const mirror::ObjectArray<mirror::Object>* object_array = 1879 obj->AsObjectArray<mirror::Object>(); 1880 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1881 if (object_array->Get(i) == ref) { 1882 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1883 } 1884 } 1885 } 1886 1887 *failed_ = true; 1888 } 1889 } 1890 } 1891 } 1892 1893 private: 1894 Heap* const heap_; 1895 bool* const failed_; 1896}; 1897 1898class VerifyLiveStackReferences { 1899 public: 1900 explicit VerifyLiveStackReferences(Heap* heap) 1901 : heap_(heap), 1902 failed_(false) {} 1903 1904 void operator()(mirror::Object* obj) const 1905 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1906 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1907 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1908 } 1909 1910 bool Failed() const { 1911 return failed_; 1912 } 1913 1914 private: 1915 Heap* const heap_; 1916 bool failed_; 1917}; 1918 1919bool Heap::VerifyMissingCardMarks() { 1920 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1921 1922 // We need to sort the live stack since we binary search it. 1923 live_stack_->Sort(); 1924 VerifyLiveStackReferences visitor(this); 1925 GetLiveBitmap()->Visit(visitor); 1926 1927 // We can verify objects in the live stack since none of these should reference dead objects. 1928 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 1929 visitor(*it); 1930 } 1931 1932 if (visitor.Failed()) { 1933 DumpSpaces(); 1934 return false; 1935 } 1936 return true; 1937} 1938 1939void Heap::SwapStacks() { 1940 allocation_stack_.swap(live_stack_); 1941} 1942 1943accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 1944 auto it = mod_union_tables_.find(space); 1945 if (it == mod_union_tables_.end()) { 1946 return nullptr; 1947 } 1948 return it->second; 1949} 1950 1951void Heap::ProcessCards(TimingLogger& timings) { 1952 // Clear cards and keep track of cards cleared in the mod-union table. 1953 for (const auto& space : continuous_spaces_) { 1954 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 1955 if (table != nullptr) { 1956 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 1957 "ImageModUnionClearCards"; 1958 TimingLogger::ScopedSplit split(name, &timings); 1959 table->ClearCards(); 1960 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 1961 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 1962 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 1963 // were dirty before the GC started. 1964 // TODO: Don't need to use atomic. 1965 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 1966 // roots and then we scan / update mod union tables after. We will always scan either card.// 1967 // If we end up with the non aged card, we scan it it in the pause. 1968 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 1969 } 1970 } 1971} 1972 1973static mirror::Object* IdentityCallback(mirror::Object* obj, void*) { 1974 return obj; 1975} 1976 1977void Heap::PreGcVerification(collector::GarbageCollector* gc) { 1978 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 1979 Thread* self = Thread::Current(); 1980 1981 if (verify_pre_gc_heap_) { 1982 thread_list->SuspendAll(); 1983 { 1984 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1985 if (!VerifyHeapReferences()) { 1986 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 1987 } 1988 } 1989 thread_list->ResumeAll(); 1990 } 1991 1992 // Check that all objects which reference things in the live stack are on dirty cards. 1993 if (verify_missing_card_marks_) { 1994 thread_list->SuspendAll(); 1995 { 1996 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1997 SwapStacks(); 1998 // Sort the live stack so that we can quickly binary search it later. 1999 if (!VerifyMissingCardMarks()) { 2000 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2001 } 2002 SwapStacks(); 2003 } 2004 thread_list->ResumeAll(); 2005 } 2006 2007 if (verify_mod_union_table_) { 2008 thread_list->SuspendAll(); 2009 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2010 for (const auto& table_pair : mod_union_tables_) { 2011 accounting::ModUnionTable* mod_union_table = table_pair.second; 2012 mod_union_table->UpdateAndMarkReferences(IdentityCallback, nullptr); 2013 mod_union_table->Verify(); 2014 } 2015 thread_list->ResumeAll(); 2016 } 2017} 2018 2019void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2020 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2021 // reachable objects. 2022 if (verify_post_gc_heap_) { 2023 Thread* self = Thread::Current(); 2024 CHECK_NE(self->GetState(), kRunnable); 2025 { 2026 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2027 // Swapping bound bitmaps does nothing. 2028 gc->SwapBitmaps(); 2029 if (!VerifyHeapReferences()) { 2030 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2031 } 2032 gc->SwapBitmaps(); 2033 } 2034 } 2035} 2036 2037void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2038 if (verify_system_weaks_) { 2039 Thread* self = Thread::Current(); 2040 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2041 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2042 mark_sweep->VerifySystemWeaks(); 2043 } 2044} 2045 2046collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2047 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2048 MutexLock mu(self, *gc_complete_lock_); 2049 return WaitForGcToCompleteLocked(self); 2050} 2051 2052collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2053 collector::GcType last_gc_type = collector::kGcTypeNone; 2054 uint64_t wait_start = NanoTime(); 2055 while (is_gc_running_) { 2056 ATRACE_BEGIN("GC: Wait For Completion"); 2057 // We must wait, change thread state then sleep on gc_complete_cond_; 2058 gc_complete_cond_->Wait(self); 2059 last_gc_type = last_gc_type_; 2060 ATRACE_END(); 2061 } 2062 uint64_t wait_time = NanoTime() - wait_start; 2063 total_wait_time_ += wait_time; 2064 if (wait_time > long_pause_log_threshold_) { 2065 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2066 } 2067 return last_gc_type; 2068} 2069 2070void Heap::DumpForSigQuit(std::ostream& os) { 2071 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2072 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2073 DumpGcPerformanceInfo(os); 2074} 2075 2076size_t Heap::GetPercentFree() { 2077 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2078} 2079 2080void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2081 if (max_allowed_footprint > GetMaxMemory()) { 2082 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2083 << PrettySize(GetMaxMemory()); 2084 max_allowed_footprint = GetMaxMemory(); 2085 } 2086 max_allowed_footprint_ = max_allowed_footprint; 2087} 2088 2089bool Heap::IsMovableObject(const mirror::Object* obj) const { 2090 if (kMovingCollector) { 2091 DCHECK(!IsInTempSpace(obj)); 2092 if (bump_pointer_space_->HasAddress(obj)) { 2093 return true; 2094 } 2095 } 2096 return false; 2097} 2098 2099bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2100 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2101 return true; 2102 } 2103 return false; 2104} 2105 2106void Heap::UpdateMaxNativeFootprint() { 2107 size_t native_size = native_bytes_allocated_; 2108 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2109 size_t target_size = native_size / GetTargetHeapUtilization(); 2110 if (target_size > native_size + max_free_) { 2111 target_size = native_size + max_free_; 2112 } else if (target_size < native_size + min_free_) { 2113 target_size = native_size + min_free_; 2114 } 2115 native_footprint_gc_watermark_ = target_size; 2116 native_footprint_limit_ = 2 * target_size - native_size; 2117} 2118 2119void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2120 // We know what our utilization is at this moment. 2121 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2122 const size_t bytes_allocated = GetBytesAllocated(); 2123 last_gc_size_ = bytes_allocated; 2124 last_gc_time_ns_ = NanoTime(); 2125 size_t target_size; 2126 if (gc_type != collector::kGcTypeSticky) { 2127 // Grow the heap for non sticky GC. 2128 target_size = bytes_allocated / GetTargetHeapUtilization(); 2129 if (target_size > bytes_allocated + max_free_) { 2130 target_size = bytes_allocated + max_free_; 2131 } else if (target_size < bytes_allocated + min_free_) { 2132 target_size = bytes_allocated + min_free_; 2133 } 2134 native_need_to_run_finalization_ = true; 2135 next_gc_type_ = collector::kGcTypeSticky; 2136 } else { 2137 // Based on how close the current heap size is to the target size, decide 2138 // whether or not to do a partial or sticky GC next. 2139 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2140 next_gc_type_ = collector::kGcTypeSticky; 2141 } else { 2142 next_gc_type_ = collector::kGcTypePartial; 2143 } 2144 // If we have freed enough memory, shrink the heap back down. 2145 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2146 target_size = bytes_allocated + max_free_; 2147 } else { 2148 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2149 } 2150 } 2151 if (!ignore_max_footprint_) { 2152 SetIdealFootprint(target_size); 2153 if (concurrent_gc_) { 2154 // Calculate when to perform the next ConcurrentGC. 2155 // Calculate the estimated GC duration. 2156 double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2157 // Estimate how many remaining bytes we will have when we need to start the next GC. 2158 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2159 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2160 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2161 // A never going to happen situation that from the estimated allocation rate we will exceed 2162 // the applications entire footprint with the given estimated allocation rate. Schedule 2163 // another GC straight away. 2164 concurrent_start_bytes_ = bytes_allocated; 2165 } else { 2166 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2167 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2168 // right away. 2169 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2170 bytes_allocated); 2171 } 2172 DCHECK_LE(concurrent_start_bytes_, max_allowed_footprint_); 2173 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2174 } 2175 } 2176} 2177 2178void Heap::ClearGrowthLimit() { 2179 growth_limit_ = capacity_; 2180 non_moving_space_->ClearGrowthLimit(); 2181} 2182 2183void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2184 MemberOffset reference_queue_offset, 2185 MemberOffset reference_queueNext_offset, 2186 MemberOffset reference_pendingNext_offset, 2187 MemberOffset finalizer_reference_zombie_offset) { 2188 reference_referent_offset_ = reference_referent_offset; 2189 reference_queue_offset_ = reference_queue_offset; 2190 reference_queueNext_offset_ = reference_queueNext_offset; 2191 reference_pendingNext_offset_ = reference_pendingNext_offset; 2192 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2193 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2194 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2195 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2196 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2197 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2198} 2199 2200void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2201 DCHECK(reference != NULL); 2202 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2203 reference->SetFieldObject(reference_referent_offset_, referent, true); 2204} 2205 2206mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2207 DCHECK(reference != NULL); 2208 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2209 return reference->GetFieldObject<mirror::Object*>(reference_referent_offset_, true); 2210} 2211 2212void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2213 ScopedObjectAccess soa(self); 2214 JValue result; 2215 ArgArray arg_array(NULL, 0); 2216 arg_array.Append(reinterpret_cast<uint32_t>(object)); 2217 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2218 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2219} 2220 2221void Heap::EnqueueClearedReferences() { 2222 if (!cleared_references_.IsEmpty()) { 2223 // When a runtime isn't started there are no reference queues to care about so ignore. 2224 if (LIKELY(Runtime::Current()->IsStarted())) { 2225 ScopedObjectAccess soa(Thread::Current()); 2226 JValue result; 2227 ArgArray arg_array(NULL, 0); 2228 arg_array.Append(reinterpret_cast<uint32_t>(cleared_references_.GetList())); 2229 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2230 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2231 } 2232 cleared_references_.Clear(); 2233 } 2234} 2235 2236void Heap::RequestConcurrentGC(Thread* self) { 2237 // Make sure that we can do a concurrent GC. 2238 Runtime* runtime = Runtime::Current(); 2239 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2240 self->IsHandlingStackOverflow()) { 2241 return; 2242 } 2243 // We already have a request pending, no reason to start more until we update 2244 // concurrent_start_bytes_. 2245 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2246 JNIEnv* env = self->GetJniEnv(); 2247 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2248 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2249 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2250 WellKnownClasses::java_lang_Daemons_requestGC); 2251 CHECK(!env->ExceptionCheck()); 2252} 2253 2254void Heap::ConcurrentGC(Thread* self) { 2255 if (Runtime::Current()->IsShuttingDown(self)) { 2256 return; 2257 } 2258 // Wait for any GCs currently running to finish. 2259 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2260 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2261 // instead. E.g. can't do partial, so do full instead. 2262 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2263 collector::kGcTypeNone) { 2264 for (collector::GcType gc_type : gc_plan_) { 2265 // Attempt to run the collector, if we succeed, we are done. 2266 if (gc_type > next_gc_type_ && 2267 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2268 break; 2269 } 2270 } 2271 } 2272 } 2273} 2274 2275void Heap::RequestHeapTrim() { 2276 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2277 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2278 // a space it will hold its lock and can become a cause of jank. 2279 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2280 // forking. 2281 2282 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2283 // because that only marks object heads, so a large array looks like lots of empty space. We 2284 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2285 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2286 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2287 // not how much use we're making of those pages. 2288 uint64_t ms_time = MilliTime(); 2289 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2290 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2291 return; 2292 } 2293 2294 Thread* self = Thread::Current(); 2295 Runtime* runtime = Runtime::Current(); 2296 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2297 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2298 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2299 // as we don't hold the lock while requesting the trim). 2300 return; 2301 } 2302 2303 last_trim_time_ms_ = ms_time; 2304 2305 // Trim only if we do not currently care about pause times. 2306 if (!CareAboutPauseTimes()) { 2307 JNIEnv* env = self->GetJniEnv(); 2308 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2309 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2310 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2311 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2312 CHECK(!env->ExceptionCheck()); 2313 } 2314} 2315 2316void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2317 if (rosalloc_space_ != nullptr) { 2318 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2319 } 2320 if (bump_pointer_space_ != nullptr) { 2321 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2322 } 2323} 2324 2325void Heap::RevokeAllThreadLocalBuffers() { 2326 if (rosalloc_space_ != nullptr) { 2327 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2328 } 2329 if (bump_pointer_space_ != nullptr) { 2330 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2331 } 2332} 2333 2334bool Heap::IsGCRequestPending() const { 2335 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2336} 2337 2338void Heap::RunFinalization(JNIEnv* env) { 2339 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2340 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2341 CHECK(WellKnownClasses::java_lang_System != nullptr); 2342 WellKnownClasses::java_lang_System_runFinalization = 2343 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2344 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2345 } 2346 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2347 WellKnownClasses::java_lang_System_runFinalization); 2348} 2349 2350void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2351 Thread* self = ThreadForEnv(env); 2352 if (native_need_to_run_finalization_) { 2353 RunFinalization(env); 2354 UpdateMaxNativeFootprint(); 2355 native_need_to_run_finalization_ = false; 2356 } 2357 // Total number of native bytes allocated. 2358 native_bytes_allocated_.FetchAndAdd(bytes); 2359 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2360 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2361 collector::kGcTypeFull; 2362 2363 // The second watermark is higher than the gc watermark. If you hit this it means you are 2364 // allocating native objects faster than the GC can keep up with. 2365 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2366 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2367 // Just finished a GC, attempt to run finalizers. 2368 RunFinalization(env); 2369 CHECK(!env->ExceptionCheck()); 2370 } 2371 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2372 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2373 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2374 RunFinalization(env); 2375 native_need_to_run_finalization_ = false; 2376 CHECK(!env->ExceptionCheck()); 2377 } 2378 // We have just run finalizers, update the native watermark since it is very likely that 2379 // finalizers released native managed allocations. 2380 UpdateMaxNativeFootprint(); 2381 } else if (!IsGCRequestPending()) { 2382 if (concurrent_gc_) { 2383 RequestConcurrentGC(self); 2384 } else { 2385 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2386 } 2387 } 2388 } 2389} 2390 2391void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2392 int expected_size, new_size; 2393 do { 2394 expected_size = native_bytes_allocated_.Load(); 2395 new_size = expected_size - bytes; 2396 if (UNLIKELY(new_size < 0)) { 2397 ScopedObjectAccess soa(env); 2398 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2399 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2400 "registered as allocated", bytes, expected_size).c_str()); 2401 break; 2402 } 2403 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2404} 2405 2406int64_t Heap::GetTotalMemory() const { 2407 int64_t ret = 0; 2408 for (const auto& space : continuous_spaces_) { 2409 // Currently don't include the image space. 2410 if (!space->IsImageSpace()) { 2411 ret += space->Size(); 2412 } 2413 } 2414 for (const auto& space : discontinuous_spaces_) { 2415 if (space->IsLargeObjectSpace()) { 2416 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2417 } 2418 } 2419 return ret; 2420} 2421 2422void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2423 DCHECK(mod_union_table != nullptr); 2424 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2425} 2426 2427} // namespace gc 2428} // namespace art 2429