heap.cc revision 96bcd45e8bd9ab5a50e005fdaf4448e2c53283ec
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 <memory> 24#include <vector> 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/remembered_set.h" 37#include "gc/accounting/space_bitmap-inl.h" 38#include "gc/collector/concurrent_copying.h" 39#include "gc/collector/mark_sweep-inl.h" 40#include "gc/collector/partial_mark_sweep.h" 41#include "gc/collector/semi_space.h" 42#include "gc/collector/sticky_mark_sweep.h" 43#include "gc/reference_processor.h" 44#include "gc/space/bump_pointer_space.h" 45#include "gc/space/dlmalloc_space-inl.h" 46#include "gc/space/image_space.h" 47#include "gc/space/large_object_space.h" 48#include "gc/space/rosalloc_space-inl.h" 49#include "gc/space/space-inl.h" 50#include "gc/space/zygote_space.h" 51#include "entrypoints/quick/quick_alloc_entrypoints.h" 52#include "heap-inl.h" 53#include "image.h" 54#include "mirror/art_field-inl.h" 55#include "mirror/class-inl.h" 56#include "mirror/object.h" 57#include "mirror/object-inl.h" 58#include "mirror/object_array-inl.h" 59#include "mirror/reference-inl.h" 60#include "object_utils.h" 61#include "os.h" 62#include "reflection.h" 63#include "runtime.h" 64#include "ScopedLocalRef.h" 65#include "scoped_thread_state_change.h" 66#include "handle_scope-inl.h" 67#include "thread_list.h" 68#include "well_known_classes.h" 69 70namespace art { 71 72namespace gc { 73 74static constexpr size_t kCollectorTransitionStressIterations = 0; 75static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 76static constexpr bool kGCALotMode = false; 77static constexpr size_t kGcAlotInterval = KB; 78// Minimum amount of remaining bytes before a concurrent GC is triggered. 79static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 80static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 81// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 82// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 83// threads (lower pauses, use less memory bandwidth). 84static constexpr double kStickyGcThroughputAdjustment = 1.0; 85// Whether or not we use the free list large object space. 86static constexpr bool kUseFreeListSpaceForLOS = false; 87// Whether or not we compact the zygote in PreZygoteFork. 88static constexpr bool kCompactZygote = kMovingCollector; 89static constexpr size_t kNonMovingSpaceCapacity = 64 * MB; 90// How many reserve entries are at the end of the allocation stack, these are only needed if the 91// allocation stack overflows. 92static constexpr size_t kAllocationStackReserveSize = 1024; 93// Default mark stack size in bytes. 94static const size_t kDefaultMarkStackSize = 64 * KB; 95 96Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 97 double target_utilization, double foreground_heap_growth_multiplier, size_t capacity, 98 const std::string& image_file_name, const InstructionSet image_instruction_set, 99 CollectorType foreground_collector_type, CollectorType background_collector_type, 100 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 101 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 102 bool ignore_max_footprint, bool use_tlab, 103 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 104 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 105 bool verify_post_gc_rosalloc) 106 : non_moving_space_(nullptr), 107 rosalloc_space_(nullptr), 108 dlmalloc_space_(nullptr), 109 main_space_(nullptr), 110 collector_type_(kCollectorTypeNone), 111 foreground_collector_type_(foreground_collector_type), 112 background_collector_type_(background_collector_type), 113 desired_collector_type_(foreground_collector_type_), 114 heap_trim_request_lock_(nullptr), 115 last_trim_time_(0), 116 heap_transition_target_time_(0), 117 heap_trim_request_pending_(false), 118 parallel_gc_threads_(parallel_gc_threads), 119 conc_gc_threads_(conc_gc_threads), 120 low_memory_mode_(low_memory_mode), 121 long_pause_log_threshold_(long_pause_log_threshold), 122 long_gc_log_threshold_(long_gc_log_threshold), 123 ignore_max_footprint_(ignore_max_footprint), 124 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 125 have_zygote_space_(false), 126 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 127 collector_type_running_(kCollectorTypeNone), 128 last_gc_type_(collector::kGcTypeNone), 129 next_gc_type_(collector::kGcTypePartial), 130 capacity_(capacity), 131 growth_limit_(growth_limit), 132 max_allowed_footprint_(initial_size), 133 native_footprint_gc_watermark_(initial_size), 134 native_footprint_limit_(2 * initial_size), 135 native_need_to_run_finalization_(false), 136 // Initially assume we perceive jank in case the process state is never updated. 137 process_state_(kProcessStateJankPerceptible), 138 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 139 total_bytes_freed_ever_(0), 140 total_objects_freed_ever_(0), 141 num_bytes_allocated_(0), 142 native_bytes_allocated_(0), 143 gc_memory_overhead_(0), 144 verify_missing_card_marks_(false), 145 verify_system_weaks_(false), 146 verify_pre_gc_heap_(verify_pre_gc_heap), 147 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 148 verify_post_gc_heap_(verify_post_gc_heap), 149 verify_mod_union_table_(false), 150 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 151 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 152 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 153 last_gc_time_ns_(NanoTime()), 154 allocation_rate_(0), 155 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 156 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 157 * verification is enabled, we limit the size of allocation stacks to speed up their 158 * searching. 159 */ 160 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 161 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 162 current_allocator_(kAllocatorTypeDlMalloc), 163 current_non_moving_allocator_(kAllocatorTypeNonMoving), 164 bump_pointer_space_(nullptr), 165 temp_space_(nullptr), 166 min_free_(min_free), 167 max_free_(max_free), 168 target_utilization_(target_utilization), 169 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 170 total_wait_time_(0), 171 total_allocation_time_(0), 172 verify_object_mode_(kVerifyObjectModeDisabled), 173 disable_moving_gc_count_(0), 174 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 175 use_tlab_(use_tlab) { 176 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 177 LOG(INFO) << "Heap() entering"; 178 } 179 const bool is_zygote = Runtime::Current()->IsZygote(); 180 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 181 // entrypoints. 182 if (!is_zygote) { 183 large_object_threshold_ = kDefaultLargeObjectThreshold; 184 // Background compaction is currently not supported for command line runs. 185 if (background_collector_type_ != foreground_collector_type_) { 186 VLOG(heap) << "Disabling background compaction for non zygote"; 187 background_collector_type_ = foreground_collector_type_; 188 } 189 } 190 ChangeCollector(desired_collector_type_); 191 192 live_bitmap_.reset(new accounting::HeapBitmap(this)); 193 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 194 // Requested begin for the alloc space, to follow the mapped image and oat files 195 byte* requested_alloc_space_begin = nullptr; 196 if (!image_file_name.empty()) { 197 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 198 image_instruction_set); 199 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 200 AddSpace(image_space); 201 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 202 // isn't going to get in the middle 203 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 204 CHECK_GT(oat_file_end_addr, image_space->End()); 205 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 206 } 207 if (is_zygote) { 208 // Reserve the address range before we create the non moving space to make sure bitmaps don't 209 // take it. 210 std::string error_str; 211 MemMap* mem_map = MemMap::MapAnonymous( 212 "main space", requested_alloc_space_begin + kNonMovingSpaceCapacity, capacity, 213 PROT_READ | PROT_WRITE, true, &error_str); 214 CHECK(mem_map != nullptr) << error_str; 215 // Non moving space is always dlmalloc since we currently don't have support for multiple 216 // rosalloc spaces. 217 non_moving_space_ = space::DlMallocSpace::Create( 218 "zygote / non moving space", initial_size, kNonMovingSpaceCapacity, kNonMovingSpaceCapacity, 219 requested_alloc_space_begin, false); 220 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 221 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 222 } else { 223 std::string error_str; 224 MemMap* mem_map = MemMap::MapAnonymous("main/non-moving space", requested_alloc_space_begin, 225 capacity, PROT_READ | PROT_WRITE, true, &error_str); 226 CHECK(mem_map != nullptr) << error_str; 227 // Create the main free list space, which doubles as the non moving space. We can do this since 228 // non zygote means that we won't have any background compaction. 229 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 230 non_moving_space_ = main_space_; 231 } 232 CHECK(non_moving_space_ != nullptr); 233 234 // We need to create the bump pointer if the foreground collector is a compacting GC. We only 235 // create the bump pointer space if we are not a moving foreground collector but have a moving 236 // background collector since the heap transition code will create the temp space by recycling 237 // the bitmap from the main space. 238 if (kMovingCollector && 239 (IsMovingGc(foreground_collector_type_) || IsMovingGc(background_collector_type_))) { 240 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 241 // Divide by 2 for a temporary fix for reducing virtual memory usage. 242 const size_t bump_pointer_space_capacity = capacity / 2; 243 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 244 bump_pointer_space_capacity, nullptr); 245 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 246 AddSpace(bump_pointer_space_); 247 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 248 bump_pointer_space_capacity, nullptr); 249 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 250 AddSpace(temp_space_); 251 } 252 if (non_moving_space_ != main_space_) { 253 AddSpace(non_moving_space_); 254 } 255 if (main_space_ != nullptr) { 256 AddSpace(main_space_); 257 } 258 259 // Allocate the large object space. 260 if (kUseFreeListSpaceForLOS) { 261 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 262 } else { 263 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 264 } 265 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 266 AddSpace(large_object_space_); 267 268 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 269 CHECK(!continuous_spaces_.empty()); 270 271 // Relies on the spaces being sorted. 272 byte* heap_begin = continuous_spaces_.front()->Begin(); 273 byte* heap_end = continuous_spaces_.back()->Limit(); 274 size_t heap_capacity = heap_end - heap_begin; 275 276 // Allocate the card table. 277 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 278 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 279 280 // Card cache for now since it makes it easier for us to update the references to the copying 281 // spaces. 282 accounting::ModUnionTable* mod_union_table = 283 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 284 GetImageSpace()); 285 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 286 AddModUnionTable(mod_union_table); 287 288 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 289 accounting::RememberedSet* non_moving_space_rem_set = 290 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 291 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 292 AddRememberedSet(non_moving_space_rem_set); 293 } 294 295 // TODO: Count objects in the image space here. 296 num_bytes_allocated_.StoreRelaxed(0); 297 298 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 299 kDefaultMarkStackSize)); 300 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 301 allocation_stack_.reset(accounting::ObjectStack::Create( 302 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 303 live_stack_.reset(accounting::ObjectStack::Create( 304 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 305 306 // It's still too early to take a lock because there are no threads yet, but we can create locks 307 // now. We don't create it earlier to make it clear that you can't use locks during heap 308 // initialization. 309 gc_complete_lock_ = new Mutex("GC complete lock"); 310 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 311 *gc_complete_lock_)); 312 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 313 last_gc_size_ = GetBytesAllocated(); 314 315 if (ignore_max_footprint_) { 316 SetIdealFootprint(std::numeric_limits<size_t>::max()); 317 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 318 } 319 CHECK_NE(max_allowed_footprint_, 0U); 320 321 // Create our garbage collectors. 322 for (size_t i = 0; i < 2; ++i) { 323 const bool concurrent = i != 0; 324 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 325 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 326 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 327 } 328 if (kMovingCollector) { 329 // TODO: Clean this up. 330 bool generational = foreground_collector_type_ == kCollectorTypeGSS; 331 semi_space_collector_ = new collector::SemiSpace(this, generational, 332 generational ? "generational" : ""); 333 garbage_collectors_.push_back(semi_space_collector_); 334 335 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 336 garbage_collectors_.push_back(concurrent_copying_collector_); 337 } 338 339 if (GetImageSpace() != nullptr && main_space_ != nullptr) { 340 // Check that there's no gap between the image space and the main 341 // space so that the immune region won't break (eg. due to a large 342 // object allocated in the gap). 343 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), main_space_->GetMemMap()); 344 if (!no_gap) { 345 MemMap::DumpMaps(LOG(ERROR)); 346 LOG(FATAL) << "There's a gap between the image space and the main space"; 347 } 348 } 349 350 if (running_on_valgrind_) { 351 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 352 } 353 354 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 355 LOG(INFO) << "Heap() exiting"; 356 } 357} 358 359void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 360 size_t capacity) { 361 // Is background compaction is enabled? 362 bool can_move_objects = IsMovingGc(background_collector_type_) != 363 IsMovingGc(foreground_collector_type_); 364 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 365 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 366 // from the main space to the zygote space. If background compaction is enabled, always pass in 367 // that we can move objets. 368 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 369 // After the zygote we want this to be false if we don't have background compaction enabled so 370 // that getting primitive array elements is faster. 371 can_move_objects = !have_zygote_space_; 372 } 373 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 374 RemoveRememberedSet(main_space_); 375 } 376 if (kUseRosAlloc) { 377 rosalloc_space_ = space::RosAllocSpace::CreateFromMemMap( 378 mem_map, "main rosalloc space", kDefaultStartingSize, initial_size, growth_limit, capacity, 379 low_memory_mode_, can_move_objects); 380 main_space_ = rosalloc_space_; 381 CHECK(main_space_ != nullptr) << "Failed to create rosalloc space"; 382 } else { 383 dlmalloc_space_ = space::DlMallocSpace::CreateFromMemMap( 384 mem_map, "main dlmalloc space", kDefaultStartingSize, initial_size, growth_limit, capacity, 385 can_move_objects); 386 main_space_ = dlmalloc_space_; 387 CHECK(main_space_ != nullptr) << "Failed to create dlmalloc space"; 388 } 389 main_space_->SetFootprintLimit(main_space_->Capacity()); 390 if (collector::SemiSpace::kUseRememberedSet) { 391 accounting::RememberedSet* main_space_rem_set = 392 new accounting::RememberedSet("Main space remembered set", this, main_space_); 393 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 394 AddRememberedSet(main_space_rem_set); 395 } 396 VLOG(heap) << "Created main space " << main_space_; 397} 398 399void Heap::ChangeAllocator(AllocatorType allocator) { 400 if (current_allocator_ != allocator) { 401 // These two allocators are only used internally and don't have any entrypoints. 402 CHECK_NE(allocator, kAllocatorTypeLOS); 403 CHECK_NE(allocator, kAllocatorTypeNonMoving); 404 current_allocator_ = allocator; 405 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 406 SetQuickAllocEntryPointsAllocator(current_allocator_); 407 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 408 } 409} 410 411void Heap::DisableCompaction() { 412 if (IsMovingGc(foreground_collector_type_)) { 413 foreground_collector_type_ = kCollectorTypeCMS; 414 } 415 if (IsMovingGc(background_collector_type_)) { 416 background_collector_type_ = foreground_collector_type_; 417 } 418 TransitionCollector(foreground_collector_type_); 419} 420 421std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 422 if (!IsValidContinuousSpaceObjectAddress(klass)) { 423 return StringPrintf("<non heap address klass %p>", klass); 424 } 425 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 426 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 427 std::string result("["); 428 result += SafeGetClassDescriptor(component_type); 429 return result; 430 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 431 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 432 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 433 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 434 } else { 435 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 436 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 437 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 438 } 439 const DexFile* dex_file = dex_cache->GetDexFile(); 440 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 441 if (class_def_idx == DexFile::kDexNoIndex16) { 442 return "<class def not found>"; 443 } 444 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 445 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 446 return dex_file->GetTypeDescriptor(type_id); 447 } 448} 449 450std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 451 if (obj == nullptr) { 452 return "null"; 453 } 454 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 455 if (klass == nullptr) { 456 return "(class=null)"; 457 } 458 std::string result(SafeGetClassDescriptor(klass)); 459 if (obj->IsClass()) { 460 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 461 } 462 return result; 463} 464 465void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 466 if (obj == nullptr) { 467 stream << "(obj=null)"; 468 return; 469 } 470 if (IsAligned<kObjectAlignment>(obj)) { 471 space::Space* space = nullptr; 472 // Don't use find space since it only finds spaces which actually contain objects instead of 473 // spaces which may contain objects (e.g. cleared bump pointer spaces). 474 for (const auto& cur_space : continuous_spaces_) { 475 if (cur_space->HasAddress(obj)) { 476 space = cur_space; 477 break; 478 } 479 } 480 // Unprotect all the spaces. 481 for (const auto& space : continuous_spaces_) { 482 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 483 } 484 stream << "Object " << obj; 485 if (space != nullptr) { 486 stream << " in space " << *space; 487 } 488 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 489 stream << "\nclass=" << klass; 490 if (klass != nullptr) { 491 stream << " type= " << SafePrettyTypeOf(obj); 492 } 493 // Re-protect the address we faulted on. 494 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 495 } 496} 497 498bool Heap::IsCompilingBoot() const { 499 for (const auto& space : continuous_spaces_) { 500 if (space->IsImageSpace() || space->IsZygoteSpace()) { 501 return false; 502 } 503 } 504 return true; 505} 506 507bool Heap::HasImageSpace() const { 508 for (const auto& space : continuous_spaces_) { 509 if (space->IsImageSpace()) { 510 return true; 511 } 512 } 513 return false; 514} 515 516void Heap::IncrementDisableMovingGC(Thread* self) { 517 // Need to do this holding the lock to prevent races where the GC is about to run / running when 518 // we attempt to disable it. 519 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 520 MutexLock mu(self, *gc_complete_lock_); 521 ++disable_moving_gc_count_; 522 if (IsMovingGc(collector_type_running_)) { 523 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 524 } 525} 526 527void Heap::DecrementDisableMovingGC(Thread* self) { 528 MutexLock mu(self, *gc_complete_lock_); 529 CHECK_GE(disable_moving_gc_count_, 0U); 530 --disable_moving_gc_count_; 531} 532 533void Heap::UpdateProcessState(ProcessState process_state) { 534 if (process_state_ != process_state) { 535 process_state_ = process_state; 536 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 537 // Start at index 1 to avoid "is always false" warning. 538 // Have iteration 1 always transition the collector. 539 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 540 ? foreground_collector_type_ : background_collector_type_); 541 usleep(kCollectorTransitionStressWait); 542 } 543 if (process_state_ == kProcessStateJankPerceptible) { 544 // Transition back to foreground right away to prevent jank. 545 RequestCollectorTransition(foreground_collector_type_, 0); 546 } else { 547 // Don't delay for debug builds since we may want to stress test the GC. 548 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 549 kCollectorTransitionWait); 550 } 551 } 552} 553 554void Heap::CreateThreadPool() { 555 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 556 if (num_threads != 0) { 557 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 558 } 559} 560 561void Heap::VisitObjects(ObjectCallback callback, void* arg) { 562 Thread* self = Thread::Current(); 563 // GCs can move objects, so don't allow this. 564 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 565 if (bump_pointer_space_ != nullptr) { 566 // Visit objects in bump pointer space. 567 bump_pointer_space_->Walk(callback, arg); 568 } 569 // TODO: Switch to standard begin and end to use ranged a based loop. 570 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 571 it < end; ++it) { 572 mirror::Object* obj = *it; 573 if (obj != nullptr && obj->GetClass() != nullptr) { 574 // Avoid the race condition caused by the object not yet being written into the allocation 575 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 576 // there can be nulls on the allocation stack. 577 callback(obj, arg); 578 } 579 } 580 GetLiveBitmap()->Walk(callback, arg); 581 self->EndAssertNoThreadSuspension(old_cause); 582} 583 584void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 585 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 586 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 587 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 588 // TODO: Generalize this to n bitmaps? 589 if (space1 == nullptr) { 590 DCHECK(space2 != nullptr); 591 space1 = space2; 592 } 593 if (space2 == nullptr) { 594 DCHECK(space1 != nullptr); 595 space2 = space1; 596 } 597 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 598 large_object_space_->GetLiveBitmap(), stack); 599} 600 601void Heap::DeleteThreadPool() { 602 thread_pool_.reset(nullptr); 603} 604 605void Heap::AddSpace(space::Space* space) { 606 DCHECK(space != nullptr); 607 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 608 if (space->IsContinuousSpace()) { 609 DCHECK(!space->IsDiscontinuousSpace()); 610 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 611 // Continuous spaces don't necessarily have bitmaps. 612 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 613 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 614 if (live_bitmap != nullptr) { 615 DCHECK(mark_bitmap != nullptr); 616 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 617 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 618 } 619 continuous_spaces_.push_back(continuous_space); 620 // Ensure that spaces remain sorted in increasing order of start address. 621 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 622 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 623 return a->Begin() < b->Begin(); 624 }); 625 } else { 626 DCHECK(space->IsDiscontinuousSpace()); 627 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 628 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 629 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 630 discontinuous_spaces_.push_back(discontinuous_space); 631 } 632 if (space->IsAllocSpace()) { 633 alloc_spaces_.push_back(space->AsAllocSpace()); 634 } 635} 636 637void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 638 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 639 if (continuous_space->IsDlMallocSpace()) { 640 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 641 } else if (continuous_space->IsRosAllocSpace()) { 642 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 643 } 644} 645 646void Heap::RemoveSpace(space::Space* space) { 647 DCHECK(space != nullptr); 648 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 649 if (space->IsContinuousSpace()) { 650 DCHECK(!space->IsDiscontinuousSpace()); 651 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 652 // Continuous spaces don't necessarily have bitmaps. 653 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 654 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 655 if (live_bitmap != nullptr) { 656 DCHECK(mark_bitmap != nullptr); 657 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 658 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 659 } 660 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 661 DCHECK(it != continuous_spaces_.end()); 662 continuous_spaces_.erase(it); 663 } else { 664 DCHECK(space->IsDiscontinuousSpace()); 665 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 666 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 667 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 668 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 669 discontinuous_space); 670 DCHECK(it != discontinuous_spaces_.end()); 671 discontinuous_spaces_.erase(it); 672 } 673 if (space->IsAllocSpace()) { 674 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 675 DCHECK(it != alloc_spaces_.end()); 676 alloc_spaces_.erase(it); 677 } 678} 679 680void Heap::RegisterGCAllocation(size_t bytes) { 681 if (this != nullptr) { 682 gc_memory_overhead_.FetchAndAddSequentiallyConsistent(bytes); 683 } 684} 685 686void Heap::RegisterGCDeAllocation(size_t bytes) { 687 if (this != nullptr) { 688 gc_memory_overhead_.FetchAndSubSequentiallyConsistent(bytes); 689 } 690} 691 692void Heap::DumpGcPerformanceInfo(std::ostream& os) { 693 // Dump cumulative timings. 694 os << "Dumping cumulative Gc timings\n"; 695 uint64_t total_duration = 0; 696 // Dump cumulative loggers for each GC type. 697 uint64_t total_paused_time = 0; 698 for (auto& collector : garbage_collectors_) { 699 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 700 const size_t iterations = logger.GetIterations(); 701 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 702 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 703 os << ConstDumpable<CumulativeLogger>(logger); 704 const uint64_t total_ns = logger.GetTotalNs(); 705 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 706 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 707 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 708 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 709 Histogram<uint64_t>::CumulativeData cumulative_data; 710 pause_histogram.CreateHistogram(&cumulative_data); 711 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 712 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 713 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 714 << collector->GetName() << " freed: " << freed_objects 715 << " objects with total size " << PrettySize(freed_bytes) << "\n" 716 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 717 << PrettySize(freed_bytes / seconds) << "/s\n"; 718 total_duration += total_ns; 719 total_paused_time += total_pause_ns; 720 } 721 collector->ResetMeasurements(); 722 } 723 uint64_t allocation_time = 724 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 725 if (total_duration != 0) { 726 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 727 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 728 os << "Mean GC size throughput: " 729 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 730 os << "Mean GC object throughput: " 731 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 732 } 733 size_t total_objects_allocated = GetObjectsAllocatedEver(); 734 os << "Total number of allocations: " << total_objects_allocated << "\n"; 735 size_t total_bytes_allocated = GetBytesAllocatedEver(); 736 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 737 if (kMeasureAllocationTime) { 738 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 739 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 740 << "\n"; 741 } 742 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 743 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 744 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_.LoadRelaxed(); 745 BaseMutex::DumpAll(os); 746} 747 748Heap::~Heap() { 749 VLOG(heap) << "Starting ~Heap()"; 750 STLDeleteElements(&garbage_collectors_); 751 // If we don't reset then the mark stack complains in its destructor. 752 allocation_stack_->Reset(); 753 live_stack_->Reset(); 754 STLDeleteValues(&mod_union_tables_); 755 STLDeleteValues(&remembered_sets_); 756 STLDeleteElements(&continuous_spaces_); 757 STLDeleteElements(&discontinuous_spaces_); 758 delete gc_complete_lock_; 759 delete heap_trim_request_lock_; 760 VLOG(heap) << "Finished ~Heap()"; 761} 762 763space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 764 bool fail_ok) const { 765 for (const auto& space : continuous_spaces_) { 766 if (space->Contains(obj)) { 767 return space; 768 } 769 } 770 if (!fail_ok) { 771 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 772 } 773 return NULL; 774} 775 776space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 777 bool fail_ok) const { 778 for (const auto& space : discontinuous_spaces_) { 779 if (space->Contains(obj)) { 780 return space; 781 } 782 } 783 if (!fail_ok) { 784 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 785 } 786 return NULL; 787} 788 789space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 790 space::Space* result = FindContinuousSpaceFromObject(obj, true); 791 if (result != NULL) { 792 return result; 793 } 794 return FindDiscontinuousSpaceFromObject(obj, true); 795} 796 797space::ImageSpace* Heap::GetImageSpace() const { 798 for (const auto& space : continuous_spaces_) { 799 if (space->IsImageSpace()) { 800 return space->AsImageSpace(); 801 } 802 } 803 return NULL; 804} 805 806static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 807 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 808 if (used_bytes < chunk_size) { 809 size_t chunk_free_bytes = chunk_size - used_bytes; 810 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 811 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 812 } 813} 814 815void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 816 std::ostringstream oss; 817 size_t total_bytes_free = GetFreeMemory(); 818 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 819 << " free bytes"; 820 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 821 if (!large_object_allocation && total_bytes_free >= byte_count) { 822 size_t max_contiguous_allocation = 0; 823 for (const auto& space : continuous_spaces_) { 824 if (space->IsMallocSpace()) { 825 // To allow the Walk/InspectAll() to exclusively-lock the mutator 826 // lock, temporarily release the shared access to the mutator 827 // lock here by transitioning to the suspended state. 828 Locks::mutator_lock_->AssertSharedHeld(self); 829 self->TransitionFromRunnableToSuspended(kSuspended); 830 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 831 self->TransitionFromSuspendedToRunnable(); 832 Locks::mutator_lock_->AssertSharedHeld(self); 833 } 834 } 835 oss << "; failed due to fragmentation (largest possible contiguous allocation " 836 << max_contiguous_allocation << " bytes)"; 837 } 838 self->ThrowOutOfMemoryError(oss.str().c_str()); 839} 840 841void Heap::DoPendingTransitionOrTrim() { 842 Thread* self = Thread::Current(); 843 CollectorType desired_collector_type; 844 // Wait until we reach the desired transition time. 845 while (true) { 846 uint64_t wait_time; 847 { 848 MutexLock mu(self, *heap_trim_request_lock_); 849 desired_collector_type = desired_collector_type_; 850 uint64_t current_time = NanoTime(); 851 if (current_time >= heap_transition_target_time_) { 852 break; 853 } 854 wait_time = heap_transition_target_time_ - current_time; 855 } 856 ScopedThreadStateChange tsc(self, kSleeping); 857 usleep(wait_time / 1000); // Usleep takes microseconds. 858 } 859 // Transition the collector if the desired collector type is not the same as the current 860 // collector type. 861 TransitionCollector(desired_collector_type); 862 if (!CareAboutPauseTimes()) { 863 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 864 // about pauses. 865 Runtime* runtime = Runtime::Current(); 866 runtime->GetThreadList()->SuspendAll(); 867 runtime->GetMonitorList()->DeflateMonitors(); 868 runtime->GetThreadList()->ResumeAll(); 869 // Do a heap trim if it is needed. 870 Trim(); 871 } 872} 873 874void Heap::Trim() { 875 Thread* self = Thread::Current(); 876 { 877 MutexLock mu(self, *heap_trim_request_lock_); 878 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 879 return; 880 } 881 last_trim_time_ = NanoTime(); 882 heap_trim_request_pending_ = false; 883 } 884 { 885 // Need to do this before acquiring the locks since we don't want to get suspended while 886 // holding any locks. 887 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 888 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 889 // trimming. 890 MutexLock mu(self, *gc_complete_lock_); 891 // Ensure there is only one GC at a time. 892 WaitForGcToCompleteLocked(kGcCauseTrim, self); 893 collector_type_running_ = kCollectorTypeHeapTrim; 894 } 895 uint64_t start_ns = NanoTime(); 896 // Trim the managed spaces. 897 uint64_t total_alloc_space_allocated = 0; 898 uint64_t total_alloc_space_size = 0; 899 uint64_t managed_reclaimed = 0; 900 for (const auto& space : continuous_spaces_) { 901 if (space->IsMallocSpace()) { 902 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 903 total_alloc_space_size += alloc_space->Size(); 904 managed_reclaimed += alloc_space->Trim(); 905 } 906 } 907 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 908 if (bump_pointer_space_ != nullptr) { 909 total_alloc_space_allocated -= bump_pointer_space_->Size(); 910 } 911 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 912 static_cast<float>(total_alloc_space_size); 913 uint64_t gc_heap_end_ns = NanoTime(); 914 // We never move things in the native heap, so we can finish the GC at this point. 915 FinishGC(self, collector::kGcTypeNone); 916 size_t native_reclaimed = 0; 917#if defined(USE_DLMALLOC) 918 // Trim the native heap. 919 dlmalloc_trim(0); 920 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 921#elif defined(USE_JEMALLOC) 922 // Jemalloc does it's own internal trimming. 923#else 924 UNIMPLEMENTED(WARNING) << "Add trimming support"; 925#endif 926 uint64_t end_ns = NanoTime(); 927 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 928 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 929 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 930 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 931 << "%."; 932} 933 934bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 935 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 936 // taking the lock. 937 if (obj == nullptr) { 938 return true; 939 } 940 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 941} 942 943bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 944 return FindContinuousSpaceFromObject(obj, true) != nullptr; 945} 946 947bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 948 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 949 return false; 950 } 951 for (const auto& space : continuous_spaces_) { 952 if (space->HasAddress(obj)) { 953 return true; 954 } 955 } 956 return false; 957} 958 959bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 960 bool search_live_stack, bool sorted) { 961 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 962 return false; 963 } 964 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 965 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 966 if (obj == klass) { 967 // This case happens for java.lang.Class. 968 return true; 969 } 970 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 971 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 972 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 973 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 974 return temp_space_->Contains(obj); 975 } 976 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 977 space::DiscontinuousSpace* d_space = nullptr; 978 if (c_space != nullptr) { 979 if (c_space->GetLiveBitmap()->Test(obj)) { 980 return true; 981 } 982 } else { 983 d_space = FindDiscontinuousSpaceFromObject(obj, true); 984 if (d_space != nullptr) { 985 if (d_space->GetLiveBitmap()->Test(obj)) { 986 return true; 987 } 988 } 989 } 990 // This is covering the allocation/live stack swapping that is done without mutators suspended. 991 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 992 if (i > 0) { 993 NanoSleep(MsToNs(10)); 994 } 995 if (search_allocation_stack) { 996 if (sorted) { 997 if (allocation_stack_->ContainsSorted(obj)) { 998 return true; 999 } 1000 } else if (allocation_stack_->Contains(obj)) { 1001 return true; 1002 } 1003 } 1004 1005 if (search_live_stack) { 1006 if (sorted) { 1007 if (live_stack_->ContainsSorted(obj)) { 1008 return true; 1009 } 1010 } else if (live_stack_->Contains(obj)) { 1011 return true; 1012 } 1013 } 1014 } 1015 // We need to check the bitmaps again since there is a race where we mark something as live and 1016 // then clear the stack containing it. 1017 if (c_space != nullptr) { 1018 if (c_space->GetLiveBitmap()->Test(obj)) { 1019 return true; 1020 } 1021 } else { 1022 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1023 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1024 return true; 1025 } 1026 } 1027 return false; 1028} 1029 1030void Heap::DumpSpaces(std::ostream& stream) { 1031 for (const auto& space : continuous_spaces_) { 1032 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1033 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1034 stream << space << " " << *space << "\n"; 1035 if (live_bitmap != nullptr) { 1036 stream << live_bitmap << " " << *live_bitmap << "\n"; 1037 } 1038 if (mark_bitmap != nullptr) { 1039 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1040 } 1041 } 1042 for (const auto& space : discontinuous_spaces_) { 1043 stream << space << " " << *space << "\n"; 1044 } 1045} 1046 1047void Heap::VerifyObjectBody(mirror::Object* obj) { 1048 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1049 return; 1050 } 1051 // Ignore early dawn of the universe verifications. 1052 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1053 return; 1054 } 1055 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1056 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1057 CHECK(c != nullptr) << "Null class in object " << obj; 1058 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1059 CHECK(VerifyClassClass(c)); 1060 1061 if (verify_object_mode_ > kVerifyObjectModeFast) { 1062 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1063 if (!IsLiveObjectLocked(obj)) { 1064 DumpSpaces(); 1065 LOG(FATAL) << "Object is dead: " << obj; 1066 } 1067 } 1068} 1069 1070void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1071 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1072} 1073 1074void Heap::VerifyHeap() { 1075 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1076 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1077} 1078 1079void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1080 // Use signed comparison since freed bytes can be negative when background compaction foreground 1081 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1082 // free list backed space typically increasing memory footprint due to padding and binning. 1083 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1084 // Note: This relies on 2s complement for handling negative freed_bytes. 1085 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1086 if (Runtime::Current()->HasStatsEnabled()) { 1087 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1088 thread_stats->freed_objects += freed_objects; 1089 thread_stats->freed_bytes += freed_bytes; 1090 // TODO: Do this concurrently. 1091 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1092 global_stats->freed_objects += freed_objects; 1093 global_stats->freed_bytes += freed_bytes; 1094 } 1095} 1096 1097mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1098 size_t alloc_size, size_t* bytes_allocated, 1099 size_t* usable_size, 1100 mirror::Class** klass) { 1101 bool was_default_allocator = allocator == GetCurrentAllocator(); 1102 DCHECK(klass != nullptr); 1103 StackHandleScope<1> hs(self); 1104 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1105 klass = nullptr; // Invalidate for safety. 1106 // The allocation failed. If the GC is running, block until it completes, and then retry the 1107 // allocation. 1108 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1109 if (last_gc != collector::kGcTypeNone) { 1110 // If we were the default allocator but the allocator changed while we were suspended, 1111 // abort the allocation. 1112 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1113 return nullptr; 1114 } 1115 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1116 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1117 usable_size); 1118 if (ptr != nullptr) { 1119 return ptr; 1120 } 1121 } 1122 1123 collector::GcType tried_type = next_gc_type_; 1124 const bool gc_ran = 1125 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1126 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1127 return nullptr; 1128 } 1129 if (gc_ran) { 1130 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1131 usable_size); 1132 if (ptr != nullptr) { 1133 return ptr; 1134 } 1135 } 1136 1137 // Loop through our different Gc types and try to Gc until we get enough free memory. 1138 for (collector::GcType gc_type : gc_plan_) { 1139 if (gc_type == tried_type) { 1140 continue; 1141 } 1142 // Attempt to run the collector, if we succeed, re-try the allocation. 1143 const bool gc_ran = 1144 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1145 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1146 return nullptr; 1147 } 1148 if (gc_ran) { 1149 // Did we free sufficient memory for the allocation to succeed? 1150 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1151 usable_size); 1152 if (ptr != nullptr) { 1153 return ptr; 1154 } 1155 } 1156 } 1157 // Allocations have failed after GCs; this is an exceptional state. 1158 // Try harder, growing the heap if necessary. 1159 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1160 usable_size); 1161 if (ptr != nullptr) { 1162 return ptr; 1163 } 1164 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1165 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1166 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1167 // OOME. 1168 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1169 << " allocation"; 1170 // TODO: Run finalization, but this may cause more allocations to occur. 1171 // We don't need a WaitForGcToComplete here either. 1172 DCHECK(!gc_plan_.empty()); 1173 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1174 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1175 return nullptr; 1176 } 1177 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1178 if (ptr == nullptr) { 1179 ThrowOutOfMemoryError(self, alloc_size, allocator == kAllocatorTypeLOS); 1180 } 1181 return ptr; 1182} 1183 1184void Heap::SetTargetHeapUtilization(float target) { 1185 DCHECK_GT(target, 0.0f); // asserted in Java code 1186 DCHECK_LT(target, 1.0f); 1187 target_utilization_ = target; 1188} 1189 1190size_t Heap::GetObjectsAllocated() const { 1191 size_t total = 0; 1192 for (space::AllocSpace* space : alloc_spaces_) { 1193 total += space->GetObjectsAllocated(); 1194 } 1195 return total; 1196} 1197 1198size_t Heap::GetObjectsAllocatedEver() const { 1199 return GetObjectsFreedEver() + GetObjectsAllocated(); 1200} 1201 1202size_t Heap::GetBytesAllocatedEver() const { 1203 return GetBytesFreedEver() + GetBytesAllocated(); 1204} 1205 1206class InstanceCounter { 1207 public: 1208 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1209 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1210 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1211 } 1212 static void Callback(mirror::Object* obj, void* arg) 1213 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1214 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1215 mirror::Class* instance_class = obj->GetClass(); 1216 CHECK(instance_class != nullptr); 1217 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1218 if (instance_counter->use_is_assignable_from_) { 1219 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1220 ++instance_counter->counts_[i]; 1221 } 1222 } else if (instance_class == instance_counter->classes_[i]) { 1223 ++instance_counter->counts_[i]; 1224 } 1225 } 1226 } 1227 1228 private: 1229 const std::vector<mirror::Class*>& classes_; 1230 bool use_is_assignable_from_; 1231 uint64_t* const counts_; 1232 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1233}; 1234 1235void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1236 uint64_t* counts) { 1237 // Can't do any GC in this function since this may move classes. 1238 Thread* self = Thread::Current(); 1239 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1240 InstanceCounter counter(classes, use_is_assignable_from, counts); 1241 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1242 VisitObjects(InstanceCounter::Callback, &counter); 1243 self->EndAssertNoThreadSuspension(old_cause); 1244} 1245 1246class InstanceCollector { 1247 public: 1248 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1249 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1250 : class_(c), max_count_(max_count), instances_(instances) { 1251 } 1252 static void Callback(mirror::Object* obj, void* arg) 1253 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1254 DCHECK(arg != nullptr); 1255 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1256 mirror::Class* instance_class = obj->GetClass(); 1257 if (instance_class == instance_collector->class_) { 1258 if (instance_collector->max_count_ == 0 || 1259 instance_collector->instances_.size() < instance_collector->max_count_) { 1260 instance_collector->instances_.push_back(obj); 1261 } 1262 } 1263 } 1264 1265 private: 1266 mirror::Class* class_; 1267 uint32_t max_count_; 1268 std::vector<mirror::Object*>& instances_; 1269 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1270}; 1271 1272void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1273 std::vector<mirror::Object*>& instances) { 1274 // Can't do any GC in this function since this may move classes. 1275 Thread* self = Thread::Current(); 1276 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1277 InstanceCollector collector(c, max_count, instances); 1278 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1279 VisitObjects(&InstanceCollector::Callback, &collector); 1280 self->EndAssertNoThreadSuspension(old_cause); 1281} 1282 1283class ReferringObjectsFinder { 1284 public: 1285 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1286 std::vector<mirror::Object*>& referring_objects) 1287 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1288 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1289 } 1290 1291 static void Callback(mirror::Object* obj, void* arg) 1292 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1293 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1294 } 1295 1296 // For bitmap Visit. 1297 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1298 // annotalysis on visitors. 1299 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1300 o->VisitReferences<true>(*this, VoidFunctor()); 1301 } 1302 1303 // For Object::VisitReferences. 1304 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1305 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1306 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1307 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1308 referring_objects_.push_back(obj); 1309 } 1310 } 1311 1312 private: 1313 mirror::Object* object_; 1314 uint32_t max_count_; 1315 std::vector<mirror::Object*>& referring_objects_; 1316 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1317}; 1318 1319void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1320 std::vector<mirror::Object*>& referring_objects) { 1321 // Can't do any GC in this function since this may move the object o. 1322 Thread* self = Thread::Current(); 1323 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1324 ReferringObjectsFinder finder(o, max_count, referring_objects); 1325 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1326 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1327 self->EndAssertNoThreadSuspension(old_cause); 1328} 1329 1330void Heap::CollectGarbage(bool clear_soft_references) { 1331 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1332 // last GC will not have necessarily been cleared. 1333 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1334} 1335 1336void Heap::TransitionCollector(CollectorType collector_type) { 1337 if (collector_type == collector_type_) { 1338 return; 1339 } 1340 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1341 << " -> " << static_cast<int>(collector_type); 1342 uint64_t start_time = NanoTime(); 1343 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1344 ThreadList* tl = Runtime::Current()->GetThreadList(); 1345 Thread* self = Thread::Current(); 1346 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1347 Locks::mutator_lock_->AssertNotHeld(self); 1348 const bool copying_transition = 1349 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1350 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1351 // compacting_gc_disable_count_, this should rarely occurs). 1352 for (;;) { 1353 { 1354 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1355 MutexLock mu(self, *gc_complete_lock_); 1356 // Ensure there is only one GC at a time. 1357 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1358 // If someone else beat us to it and changed the collector before we could, exit. 1359 // This is safe to do before the suspend all since we set the collector_type_running_ before 1360 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1361 // then it would get blocked on WaitForGcToCompleteLocked. 1362 if (collector_type == collector_type_) { 1363 return; 1364 } 1365 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1366 if (!copying_transition || disable_moving_gc_count_ == 0) { 1367 // TODO: Not hard code in semi-space collector? 1368 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1369 break; 1370 } 1371 } 1372 usleep(1000); 1373 } 1374 if (Runtime::Current()->IsShuttingDown(self)) { 1375 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1376 // cause objects to get finalized. 1377 FinishGC(self, collector::kGcTypeNone); 1378 return; 1379 } 1380 tl->SuspendAll(); 1381 switch (collector_type) { 1382 case kCollectorTypeSS: 1383 // Fall-through. 1384 case kCollectorTypeGSS: { 1385 if (!IsMovingGc(collector_type_)) { 1386 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1387 // pointer space last transition it will be protected. 1388 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1389 Compact(bump_pointer_space_, main_space_); 1390 // Remove the main space so that we don't try to trim it, this doens't work for debug 1391 // builds since RosAlloc attempts to read the magic number from a protected page. 1392 RemoveSpace(main_space_); 1393 } 1394 break; 1395 } 1396 case kCollectorTypeMS: 1397 // Fall through. 1398 case kCollectorTypeCMS: { 1399 if (IsMovingGc(collector_type_)) { 1400 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1401 AddSpace(main_space_); 1402 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1403 Compact(main_space_, bump_pointer_space_); 1404 } 1405 break; 1406 } 1407 default: { 1408 LOG(FATAL) << "Attempted to transition to invalid collector type " 1409 << static_cast<size_t>(collector_type); 1410 break; 1411 } 1412 } 1413 ChangeCollector(collector_type); 1414 tl->ResumeAll(); 1415 // Can't call into java code with all threads suspended. 1416 reference_processor_.EnqueueClearedReferences(); 1417 uint64_t duration = NanoTime() - start_time; 1418 GrowForUtilization(semi_space_collector_); 1419 FinishGC(self, collector::kGcTypeFull); 1420 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1421 int32_t delta_allocated = before_allocated - after_allocated; 1422 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1423 << PrettyDuration(duration) << " saved at least " << PrettySize(delta_allocated); 1424} 1425 1426void Heap::ChangeCollector(CollectorType collector_type) { 1427 // TODO: Only do this with all mutators suspended to avoid races. 1428 if (collector_type != collector_type_) { 1429 collector_type_ = collector_type; 1430 gc_plan_.clear(); 1431 switch (collector_type_) { 1432 case kCollectorTypeCC: // Fall-through. 1433 case kCollectorTypeSS: // Fall-through. 1434 case kCollectorTypeGSS: { 1435 gc_plan_.push_back(collector::kGcTypeFull); 1436 if (use_tlab_) { 1437 ChangeAllocator(kAllocatorTypeTLAB); 1438 } else { 1439 ChangeAllocator(kAllocatorTypeBumpPointer); 1440 } 1441 break; 1442 } 1443 case kCollectorTypeMS: { 1444 gc_plan_.push_back(collector::kGcTypeSticky); 1445 gc_plan_.push_back(collector::kGcTypePartial); 1446 gc_plan_.push_back(collector::kGcTypeFull); 1447 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1448 break; 1449 } 1450 case kCollectorTypeCMS: { 1451 gc_plan_.push_back(collector::kGcTypeSticky); 1452 gc_plan_.push_back(collector::kGcTypePartial); 1453 gc_plan_.push_back(collector::kGcTypeFull); 1454 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1455 break; 1456 } 1457 default: { 1458 LOG(FATAL) << "Unimplemented"; 1459 } 1460 } 1461 if (IsGcConcurrent()) { 1462 concurrent_start_bytes_ = 1463 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1464 } else { 1465 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1466 } 1467 } 1468} 1469 1470// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1471class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1472 public: 1473 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1474 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1475 } 1476 1477 void BuildBins(space::ContinuousSpace* space) { 1478 bin_live_bitmap_ = space->GetLiveBitmap(); 1479 bin_mark_bitmap_ = space->GetMarkBitmap(); 1480 BinContext context; 1481 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1482 context.collector_ = this; 1483 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1484 // Note: This requires traversing the space in increasing order of object addresses. 1485 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1486 // Add the last bin which spans after the last object to the end of the space. 1487 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1488 } 1489 1490 private: 1491 struct BinContext { 1492 uintptr_t prev_; // The end of the previous object. 1493 ZygoteCompactingCollector* collector_; 1494 }; 1495 // Maps from bin sizes to locations. 1496 std::multimap<size_t, uintptr_t> bins_; 1497 // Live bitmap of the space which contains the bins. 1498 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1499 // Mark bitmap of the space which contains the bins. 1500 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1501 1502 static void Callback(mirror::Object* obj, void* arg) 1503 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1504 DCHECK(arg != nullptr); 1505 BinContext* context = reinterpret_cast<BinContext*>(arg); 1506 ZygoteCompactingCollector* collector = context->collector_; 1507 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1508 size_t bin_size = object_addr - context->prev_; 1509 // Add the bin consisting of the end of the previous object to the start of the current object. 1510 collector->AddBin(bin_size, context->prev_); 1511 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1512 } 1513 1514 void AddBin(size_t size, uintptr_t position) { 1515 if (size != 0) { 1516 bins_.insert(std::make_pair(size, position)); 1517 } 1518 } 1519 1520 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1521 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1522 // allocator. 1523 return false; 1524 } 1525 1526 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1527 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1528 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1529 mirror::Object* forward_address; 1530 // Find the smallest bin which we can move obj in. 1531 auto it = bins_.lower_bound(object_size); 1532 if (it == bins_.end()) { 1533 // No available space in the bins, place it in the target space instead (grows the zygote 1534 // space). 1535 size_t bytes_allocated; 1536 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1537 if (to_space_live_bitmap_ != nullptr) { 1538 to_space_live_bitmap_->Set(forward_address); 1539 } else { 1540 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1541 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1542 } 1543 } else { 1544 size_t size = it->first; 1545 uintptr_t pos = it->second; 1546 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1547 forward_address = reinterpret_cast<mirror::Object*>(pos); 1548 // Set the live and mark bits so that sweeping system weaks works properly. 1549 bin_live_bitmap_->Set(forward_address); 1550 bin_mark_bitmap_->Set(forward_address); 1551 DCHECK_GE(size, object_size); 1552 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1553 } 1554 // Copy the object over to its new location. 1555 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1556 if (kUseBakerOrBrooksReadBarrier) { 1557 obj->AssertReadBarrierPointer(); 1558 if (kUseBrooksReadBarrier) { 1559 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1560 forward_address->SetReadBarrierPointer(forward_address); 1561 } 1562 forward_address->AssertReadBarrierPointer(); 1563 } 1564 return forward_address; 1565 } 1566}; 1567 1568void Heap::UnBindBitmaps() { 1569 for (const auto& space : GetContinuousSpaces()) { 1570 if (space->IsContinuousMemMapAllocSpace()) { 1571 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1572 if (alloc_space->HasBoundBitmaps()) { 1573 alloc_space->UnBindBitmaps(); 1574 } 1575 } 1576 } 1577} 1578 1579void Heap::PreZygoteFork() { 1580 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1581 Thread* self = Thread::Current(); 1582 MutexLock mu(self, zygote_creation_lock_); 1583 // Try to see if we have any Zygote spaces. 1584 if (have_zygote_space_) { 1585 return; 1586 } 1587 VLOG(heap) << "Starting PreZygoteFork"; 1588 // Trim the pages at the end of the non moving space. 1589 non_moving_space_->Trim(); 1590 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1591 // there. 1592 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1593 // Change the collector to the post zygote one. 1594 if (kCompactZygote) { 1595 DCHECK(semi_space_collector_ != nullptr); 1596 // Temporarily disable rosalloc verification because the zygote 1597 // compaction will mess up the rosalloc internal metadata. 1598 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1599 ZygoteCompactingCollector zygote_collector(this); 1600 zygote_collector.BuildBins(non_moving_space_); 1601 // Create a new bump pointer space which we will compact into. 1602 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1603 non_moving_space_->Limit()); 1604 // Compact the bump pointer space to a new zygote bump pointer space. 1605 bool reset_main_space = false; 1606 if (IsMovingGc(collector_type_)) { 1607 zygote_collector.SetFromSpace(bump_pointer_space_); 1608 } else { 1609 CHECK(main_space_ != nullptr); 1610 // Copy from the main space. 1611 zygote_collector.SetFromSpace(main_space_); 1612 reset_main_space = true; 1613 } 1614 zygote_collector.SetToSpace(&target_space); 1615 zygote_collector.SetSwapSemiSpaces(false); 1616 zygote_collector.Run(kGcCauseCollectorTransition, false); 1617 if (reset_main_space) { 1618 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1619 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1620 MemMap* mem_map = main_space_->ReleaseMemMap(); 1621 RemoveSpace(main_space_); 1622 space::Space* old_main_space = main_space_; 1623 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1624 delete old_main_space; 1625 AddSpace(main_space_); 1626 } else { 1627 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1628 } 1629 if (temp_space_ != nullptr) { 1630 CHECK(temp_space_->IsEmpty()); 1631 } 1632 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1633 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1634 // Update the end and write out image. 1635 non_moving_space_->SetEnd(target_space.End()); 1636 non_moving_space_->SetLimit(target_space.Limit()); 1637 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1638 } 1639 ChangeCollector(foreground_collector_type_); 1640 // Save the old space so that we can remove it after we complete creating the zygote space. 1641 space::MallocSpace* old_alloc_space = non_moving_space_; 1642 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1643 // the remaining available space. 1644 // Remove the old space before creating the zygote space since creating the zygote space sets 1645 // the old alloc space's bitmaps to nullptr. 1646 RemoveSpace(old_alloc_space); 1647 if (collector::SemiSpace::kUseRememberedSet) { 1648 // Sanity bound check. 1649 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1650 // Remove the remembered set for the now zygote space (the old 1651 // non-moving space). Note now that we have compacted objects into 1652 // the zygote space, the data in the remembered set is no longer 1653 // needed. The zygote space will instead have a mod-union table 1654 // from this point on. 1655 RemoveRememberedSet(old_alloc_space); 1656 } 1657 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1658 low_memory_mode_, 1659 &non_moving_space_); 1660 delete old_alloc_space; 1661 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1662 AddSpace(zygote_space); 1663 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1664 AddSpace(non_moving_space_); 1665 have_zygote_space_ = true; 1666 // Enable large object space allocations. 1667 large_object_threshold_ = kDefaultLargeObjectThreshold; 1668 // Create the zygote space mod union table. 1669 accounting::ModUnionTable* mod_union_table = 1670 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1671 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1672 AddModUnionTable(mod_union_table); 1673 if (collector::SemiSpace::kUseRememberedSet) { 1674 // Add a new remembered set for the post-zygote non-moving space. 1675 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1676 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1677 non_moving_space_); 1678 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1679 << "Failed to create post-zygote non-moving space remembered set"; 1680 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1681 } 1682} 1683 1684void Heap::FlushAllocStack() { 1685 MarkAllocStackAsLive(allocation_stack_.get()); 1686 allocation_stack_->Reset(); 1687} 1688 1689void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 1690 accounting::ContinuousSpaceBitmap* bitmap2, 1691 accounting::LargeObjectBitmap* large_objects, 1692 accounting::ObjectStack* stack) { 1693 DCHECK(bitmap1 != nullptr); 1694 DCHECK(bitmap2 != nullptr); 1695 mirror::Object** limit = stack->End(); 1696 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1697 const mirror::Object* obj = *it; 1698 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1699 if (bitmap1->HasAddress(obj)) { 1700 bitmap1->Set(obj); 1701 } else if (bitmap2->HasAddress(obj)) { 1702 bitmap2->Set(obj); 1703 } else { 1704 large_objects->Set(obj); 1705 } 1706 } 1707 } 1708} 1709 1710void Heap::SwapSemiSpaces() { 1711 CHECK(bump_pointer_space_ != nullptr); 1712 CHECK(temp_space_ != nullptr); 1713 std::swap(bump_pointer_space_, temp_space_); 1714} 1715 1716void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1717 space::ContinuousMemMapAllocSpace* source_space) { 1718 CHECK(kMovingCollector); 1719 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1720 if (target_space != source_space) { 1721 // Don't swap spaces since this isn't a typical semi space collection. 1722 semi_space_collector_->SetSwapSemiSpaces(false); 1723 semi_space_collector_->SetFromSpace(source_space); 1724 semi_space_collector_->SetToSpace(target_space); 1725 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1726 } 1727} 1728 1729collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1730 bool clear_soft_references) { 1731 Thread* self = Thread::Current(); 1732 Runtime* runtime = Runtime::Current(); 1733 // If the heap can't run the GC, silently fail and return that no GC was run. 1734 switch (gc_type) { 1735 case collector::kGcTypePartial: { 1736 if (!have_zygote_space_) { 1737 return collector::kGcTypeNone; 1738 } 1739 break; 1740 } 1741 default: { 1742 // Other GC types don't have any special cases which makes them not runnable. The main case 1743 // here is full GC. 1744 } 1745 } 1746 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1747 Locks::mutator_lock_->AssertNotHeld(self); 1748 if (self->IsHandlingStackOverflow()) { 1749 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1750 } 1751 bool compacting_gc; 1752 { 1753 gc_complete_lock_->AssertNotHeld(self); 1754 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1755 MutexLock mu(self, *gc_complete_lock_); 1756 // Ensure there is only one GC at a time. 1757 WaitForGcToCompleteLocked(gc_cause, self); 1758 compacting_gc = IsMovingGc(collector_type_); 1759 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1760 if (compacting_gc && disable_moving_gc_count_ != 0) { 1761 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1762 return collector::kGcTypeNone; 1763 } 1764 collector_type_running_ = collector_type_; 1765 } 1766 1767 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1768 ++runtime->GetStats()->gc_for_alloc_count; 1769 ++self->GetStats()->gc_for_alloc_count; 1770 } 1771 uint64_t gc_start_time_ns = NanoTime(); 1772 uint64_t gc_start_size = GetBytesAllocated(); 1773 // Approximate allocation rate in bytes / second. 1774 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1775 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1776 if (LIKELY(ms_delta != 0)) { 1777 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1778 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1779 } 1780 1781 DCHECK_LT(gc_type, collector::kGcTypeMax); 1782 DCHECK_NE(gc_type, collector::kGcTypeNone); 1783 1784 collector::GarbageCollector* collector = nullptr; 1785 // TODO: Clean this up. 1786 if (compacting_gc) { 1787 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1788 current_allocator_ == kAllocatorTypeTLAB); 1789 if (collector_type_ == kCollectorTypeSS || collector_type_ == kCollectorTypeGSS) { 1790 gc_type = semi_space_collector_->GetGcType(); 1791 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1792 semi_space_collector_->SetToSpace(temp_space_); 1793 collector = semi_space_collector_; 1794 semi_space_collector_->SetSwapSemiSpaces(true); 1795 } else if (collector_type_ == kCollectorTypeCC) { 1796 gc_type = concurrent_copying_collector_->GetGcType(); 1797 collector = concurrent_copying_collector_; 1798 } else { 1799 LOG(FATAL) << "Unreachable - invalid collector type " << static_cast<size_t>(collector_type_); 1800 } 1801 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1802 CHECK(temp_space_->IsEmpty()); 1803 gc_type = collector::kGcTypeFull; 1804 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1805 current_allocator_ == kAllocatorTypeDlMalloc) { 1806 collector = FindCollectorByGcType(gc_type); 1807 } else { 1808 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1809 } 1810 CHECK(collector != nullptr) 1811 << "Could not find garbage collector with collector_type=" 1812 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1813 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1814 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1815 total_objects_freed_ever_ += collector->GetFreedObjects(); 1816 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1817 RequestHeapTrim(); 1818 // Enqueue cleared references. 1819 reference_processor_.EnqueueClearedReferences(); 1820 // Grow the heap so that we know when to perform the next GC. 1821 GrowForUtilization(collector); 1822 const size_t duration = collector->GetDurationNs(); 1823 const std::vector<uint64_t>& pause_times = collector->GetPauseTimes(); 1824 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 1825 // (mutator time blocked >= long_pause_log_threshold_). 1826 bool log_gc = gc_cause == kGcCauseExplicit; 1827 if (!log_gc && CareAboutPauseTimes()) { 1828 // GC for alloc pauses the allocating thread, so consider it as a pause. 1829 log_gc = duration > long_gc_log_threshold_ || 1830 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1831 for (uint64_t pause : pause_times) { 1832 log_gc = log_gc || pause >= long_pause_log_threshold_; 1833 } 1834 } 1835 if (log_gc) { 1836 const size_t percent_free = GetPercentFree(); 1837 const size_t current_heap_size = GetBytesAllocated(); 1838 const size_t total_memory = GetTotalMemory(); 1839 std::ostringstream pause_string; 1840 for (size_t i = 0; i < pause_times.size(); ++i) { 1841 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 1842 << ((i != pause_times.size() - 1) ? "," : ""); 1843 } 1844 LOG(INFO) << gc_cause << " " << collector->GetName() 1845 << " GC freed " << collector->GetFreedObjects() << "(" 1846 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1847 << collector->GetFreedLargeObjects() << "(" 1848 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1849 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1850 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1851 << " total " << PrettyDuration((duration / 1000) * 1000); 1852 VLOG(heap) << ConstDumpable<TimingLogger>(collector->GetTimings()); 1853 } 1854 FinishGC(self, gc_type); 1855 ATRACE_END(); 1856 1857 // Inform DDMS that a GC completed. 1858 Dbg::GcDidFinish(); 1859 return gc_type; 1860} 1861 1862void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1863 MutexLock mu(self, *gc_complete_lock_); 1864 collector_type_running_ = kCollectorTypeNone; 1865 if (gc_type != collector::kGcTypeNone) { 1866 last_gc_type_ = gc_type; 1867 } 1868 // Wake anyone who may have been waiting for the GC to complete. 1869 gc_complete_cond_->Broadcast(self); 1870} 1871 1872static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1873 RootType /*root_type*/) { 1874 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1875 if (*root == obj) { 1876 LOG(INFO) << "Object " << obj << " is a root"; 1877 } 1878} 1879 1880class ScanVisitor { 1881 public: 1882 void operator()(const mirror::Object* obj) const { 1883 LOG(ERROR) << "Would have rescanned object " << obj; 1884 } 1885}; 1886 1887// Verify a reference from an object. 1888class VerifyReferenceVisitor { 1889 public: 1890 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 1891 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1892 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 1893 1894 size_t GetFailureCount() const { 1895 return fail_count_->LoadSequentiallyConsistent(); 1896 } 1897 1898 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1899 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1900 if (verify_referent_) { 1901 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 1902 } 1903 } 1904 1905 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1906 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1907 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 1908 } 1909 1910 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1911 return heap_->IsLiveObjectLocked(obj, true, false, true); 1912 } 1913 1914 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 1915 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1916 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1917 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 1918 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 1919 << " thread_id= " << thread_id << " root_type= " << root_type; 1920 } 1921 } 1922 1923 private: 1924 // TODO: Fix the no thread safety analysis. 1925 // Returns false on failure. 1926 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1927 NO_THREAD_SAFETY_ANALYSIS { 1928 if (ref == nullptr || IsLive(ref)) { 1929 // Verify that the reference is live. 1930 return true; 1931 } 1932 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 1933 // Print message on only on first failure to prevent spam. 1934 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1935 } 1936 if (obj != nullptr) { 1937 // Only do this part for non roots. 1938 accounting::CardTable* card_table = heap_->GetCardTable(); 1939 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1940 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1941 byte* card_addr = card_table->CardFromAddr(obj); 1942 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1943 << offset << "\n card value = " << static_cast<int>(*card_addr); 1944 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1945 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1946 } else { 1947 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1948 } 1949 1950 // Attmept to find the class inside of the recently freed objects. 1951 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1952 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1953 space::MallocSpace* space = ref_space->AsMallocSpace(); 1954 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1955 if (ref_class != nullptr) { 1956 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1957 << PrettyClass(ref_class); 1958 } else { 1959 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1960 } 1961 } 1962 1963 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1964 ref->GetClass()->IsClass()) { 1965 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1966 } else { 1967 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1968 << ") is not a valid heap address"; 1969 } 1970 1971 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1972 void* cover_begin = card_table->AddrFromCard(card_addr); 1973 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1974 accounting::CardTable::kCardSize); 1975 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1976 << "-" << cover_end; 1977 accounting::ContinuousSpaceBitmap* bitmap = 1978 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1979 1980 if (bitmap == nullptr) { 1981 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1982 if (!VerifyClassClass(obj->GetClass())) { 1983 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1984 } 1985 } else { 1986 // Print out how the object is live. 1987 if (bitmap->Test(obj)) { 1988 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1989 } 1990 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1991 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1992 } 1993 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1994 LOG(ERROR) << "Object " << obj << " found in live stack"; 1995 } 1996 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1997 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1998 } 1999 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2000 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2001 } 2002 // Attempt to see if the card table missed the reference. 2003 ScanVisitor scan_visitor; 2004 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2005 card_table->Scan(bitmap, byte_cover_begin, 2006 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2007 } 2008 2009 // Search to see if any of the roots reference our object. 2010 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2011 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2012 2013 // Search to see if any of the roots reference our reference. 2014 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2015 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2016 } 2017 return false; 2018 } 2019 2020 Heap* const heap_; 2021 Atomic<size_t>* const fail_count_; 2022 const bool verify_referent_; 2023}; 2024 2025// Verify all references within an object, for use with HeapBitmap::Visit. 2026class VerifyObjectVisitor { 2027 public: 2028 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2029 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2030 } 2031 2032 void operator()(mirror::Object* obj) const 2033 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2034 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2035 // be live or else how did we find it in the live bitmap? 2036 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2037 // The class doesn't count as a reference but we should verify it anyways. 2038 obj->VisitReferences<true>(visitor, visitor); 2039 } 2040 2041 static void VisitCallback(mirror::Object* obj, void* arg) 2042 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2043 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2044 visitor->operator()(obj); 2045 } 2046 2047 size_t GetFailureCount() const { 2048 return fail_count_->LoadSequentiallyConsistent(); 2049 } 2050 2051 private: 2052 Heap* const heap_; 2053 Atomic<size_t>* const fail_count_; 2054 const bool verify_referent_; 2055}; 2056 2057void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2058 // Slow path, the allocation stack push back must have already failed. 2059 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2060 do { 2061 // TODO: Add handle VerifyObject. 2062 StackHandleScope<1> hs(self); 2063 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2064 // Push our object into the reserve region of the allocaiton stack. This is only required due 2065 // to heap verification requiring that roots are live (either in the live bitmap or in the 2066 // allocation stack). 2067 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2068 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2069 } while (!allocation_stack_->AtomicPushBack(*obj)); 2070} 2071 2072void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2073 // Slow path, the allocation stack push back must have already failed. 2074 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2075 mirror::Object** start_address; 2076 mirror::Object** end_address; 2077 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2078 &end_address)) { 2079 // TODO: Add handle VerifyObject. 2080 StackHandleScope<1> hs(self); 2081 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2082 // Push our object into the reserve region of the allocaiton stack. This is only required due 2083 // to heap verification requiring that roots are live (either in the live bitmap or in the 2084 // allocation stack). 2085 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2086 // Push into the reserve allocation stack. 2087 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2088 } 2089 self->SetThreadLocalAllocationStack(start_address, end_address); 2090 // Retry on the new thread-local allocation stack. 2091 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2092} 2093 2094// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2095size_t Heap::VerifyHeapReferences(bool verify_referents) { 2096 Thread* self = Thread::Current(); 2097 Locks::mutator_lock_->AssertExclusiveHeld(self); 2098 // Lets sort our allocation stacks so that we can efficiently binary search them. 2099 allocation_stack_->Sort(); 2100 live_stack_->Sort(); 2101 // Since we sorted the allocation stack content, need to revoke all 2102 // thread-local allocation stacks. 2103 RevokeAllThreadLocalAllocationStacks(self); 2104 Atomic<size_t> fail_count_(0); 2105 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2106 // Verify objects in the allocation stack since these will be objects which were: 2107 // 1. Allocated prior to the GC (pre GC verification). 2108 // 2. Allocated during the GC (pre sweep GC verification). 2109 // We don't want to verify the objects in the live stack since they themselves may be 2110 // pointing to dead objects if they are not reachable. 2111 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2112 // Verify the roots: 2113 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2114 if (visitor.GetFailureCount() > 0) { 2115 // Dump mod-union tables. 2116 for (const auto& table_pair : mod_union_tables_) { 2117 accounting::ModUnionTable* mod_union_table = table_pair.second; 2118 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2119 } 2120 // Dump remembered sets. 2121 for (const auto& table_pair : remembered_sets_) { 2122 accounting::RememberedSet* remembered_set = table_pair.second; 2123 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2124 } 2125 DumpSpaces(); 2126 } 2127 return visitor.GetFailureCount(); 2128} 2129 2130class VerifyReferenceCardVisitor { 2131 public: 2132 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2133 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2134 Locks::heap_bitmap_lock_) 2135 : heap_(heap), failed_(failed) { 2136 } 2137 2138 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2139 // annotalysis on visitors. 2140 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2141 NO_THREAD_SAFETY_ANALYSIS { 2142 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2143 // Filter out class references since changing an object's class does not mark the card as dirty. 2144 // Also handles large objects, since the only reference they hold is a class reference. 2145 if (ref != nullptr && !ref->IsClass()) { 2146 accounting::CardTable* card_table = heap_->GetCardTable(); 2147 // If the object is not dirty and it is referencing something in the live stack other than 2148 // class, then it must be on a dirty card. 2149 if (!card_table->AddrIsInCardTable(obj)) { 2150 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2151 *failed_ = true; 2152 } else if (!card_table->IsDirty(obj)) { 2153 // TODO: Check mod-union tables. 2154 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2155 // kCardDirty - 1 if it didnt get touched since we aged it. 2156 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2157 if (live_stack->ContainsSorted(ref)) { 2158 if (live_stack->ContainsSorted(obj)) { 2159 LOG(ERROR) << "Object " << obj << " found in live stack"; 2160 } 2161 if (heap_->GetLiveBitmap()->Test(obj)) { 2162 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2163 } 2164 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2165 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2166 2167 // Print which field of the object is dead. 2168 if (!obj->IsObjectArray()) { 2169 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2170 CHECK(klass != NULL); 2171 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2172 : klass->GetIFields(); 2173 CHECK(fields != NULL); 2174 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2175 mirror::ArtField* cur = fields->Get(i); 2176 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2177 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2178 << PrettyField(cur); 2179 break; 2180 } 2181 } 2182 } else { 2183 mirror::ObjectArray<mirror::Object>* object_array = 2184 obj->AsObjectArray<mirror::Object>(); 2185 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2186 if (object_array->Get(i) == ref) { 2187 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2188 } 2189 } 2190 } 2191 2192 *failed_ = true; 2193 } 2194 } 2195 } 2196 } 2197 2198 private: 2199 Heap* const heap_; 2200 bool* const failed_; 2201}; 2202 2203class VerifyLiveStackReferences { 2204 public: 2205 explicit VerifyLiveStackReferences(Heap* heap) 2206 : heap_(heap), 2207 failed_(false) {} 2208 2209 void operator()(mirror::Object* obj) const 2210 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2211 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2212 obj->VisitReferences<true>(visitor, VoidFunctor()); 2213 } 2214 2215 bool Failed() const { 2216 return failed_; 2217 } 2218 2219 private: 2220 Heap* const heap_; 2221 bool failed_; 2222}; 2223 2224bool Heap::VerifyMissingCardMarks() { 2225 Thread* self = Thread::Current(); 2226 Locks::mutator_lock_->AssertExclusiveHeld(self); 2227 2228 // We need to sort the live stack since we binary search it. 2229 live_stack_->Sort(); 2230 // Since we sorted the allocation stack content, need to revoke all 2231 // thread-local allocation stacks. 2232 RevokeAllThreadLocalAllocationStacks(self); 2233 VerifyLiveStackReferences visitor(this); 2234 GetLiveBitmap()->Visit(visitor); 2235 2236 // We can verify objects in the live stack since none of these should reference dead objects. 2237 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2238 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2239 visitor(*it); 2240 } 2241 } 2242 2243 if (visitor.Failed()) { 2244 DumpSpaces(); 2245 return false; 2246 } 2247 return true; 2248} 2249 2250void Heap::SwapStacks(Thread* self) { 2251 if (kUseThreadLocalAllocationStack) { 2252 live_stack_->AssertAllZero(); 2253 } 2254 allocation_stack_.swap(live_stack_); 2255} 2256 2257void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2258 // This must be called only during the pause. 2259 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2260 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2261 MutexLock mu2(self, *Locks::thread_list_lock_); 2262 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2263 for (Thread* t : thread_list) { 2264 t->RevokeThreadLocalAllocationStack(); 2265 } 2266} 2267 2268void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2269 if (kIsDebugBuild) { 2270 if (bump_pointer_space_ != nullptr) { 2271 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2272 } 2273 } 2274} 2275 2276accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2277 auto it = mod_union_tables_.find(space); 2278 if (it == mod_union_tables_.end()) { 2279 return nullptr; 2280 } 2281 return it->second; 2282} 2283 2284accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2285 auto it = remembered_sets_.find(space); 2286 if (it == remembered_sets_.end()) { 2287 return nullptr; 2288 } 2289 return it->second; 2290} 2291 2292void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2293 // Clear cards and keep track of cards cleared in the mod-union table. 2294 for (const auto& space : continuous_spaces_) { 2295 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2296 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2297 if (table != nullptr) { 2298 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2299 "ImageModUnionClearCards"; 2300 TimingLogger::ScopedSplit split(name, &timings); 2301 table->ClearCards(); 2302 } else if (use_rem_sets && rem_set != nullptr) { 2303 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2304 << static_cast<int>(collector_type_); 2305 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2306 rem_set->ClearCards(); 2307 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2308 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2309 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2310 // were dirty before the GC started. 2311 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2312 // -> clean(cleaning thread). 2313 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2314 // roots and then we scan / update mod union tables after. We will always scan either card. 2315 // If we end up with the non aged card, we scan it it in the pause. 2316 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2317 } 2318 } 2319} 2320 2321static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2322} 2323 2324void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2325 Thread* const self = Thread::Current(); 2326 TimingLogger* const timings = &gc->GetTimings(); 2327 if (verify_pre_gc_heap_) { 2328 TimingLogger::ScopedSplit split("PreGcVerifyHeapReferences", timings); 2329 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2330 size_t failures = VerifyHeapReferences(); 2331 if (failures > 0) { 2332 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2333 << " failures"; 2334 } 2335 } 2336 // Check that all objects which reference things in the live stack are on dirty cards. 2337 if (verify_missing_card_marks_) { 2338 TimingLogger::ScopedSplit split("PreGcVerifyMissingCardMarks", timings); 2339 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2340 SwapStacks(self); 2341 // Sort the live stack so that we can quickly binary search it later. 2342 if (!VerifyMissingCardMarks()) { 2343 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2344 } 2345 SwapStacks(self); 2346 } 2347 if (verify_mod_union_table_) { 2348 TimingLogger::ScopedSplit split("PreGcVerifyModUnionTables", timings); 2349 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2350 for (const auto& table_pair : mod_union_tables_) { 2351 accounting::ModUnionTable* mod_union_table = table_pair.second; 2352 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2353 mod_union_table->Verify(); 2354 } 2355 } 2356} 2357 2358void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2359 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2360 collector::GarbageCollector::ScopedPause pause(gc); 2361 PreGcVerificationPaused(gc); 2362 } 2363} 2364 2365void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2366 // TODO: Add a new runtime option for this? 2367 if (verify_pre_gc_rosalloc_) { 2368 RosAllocVerification(&gc->GetTimings(), "PreGcRosAllocVerification"); 2369 } 2370} 2371 2372void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2373 Thread* const self = Thread::Current(); 2374 TimingLogger* const timings = &gc->GetTimings(); 2375 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2376 // reachable objects. 2377 if (verify_pre_sweeping_heap_) { 2378 TimingLogger::ScopedSplit split("PostSweepingVerifyHeapReferences", timings); 2379 CHECK_NE(self->GetState(), kRunnable); 2380 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2381 // Swapping bound bitmaps does nothing. 2382 gc->SwapBitmaps(); 2383 // Pass in false since concurrent reference processing can mean that the reference referents 2384 // may point to dead objects at the point which PreSweepingGcVerification is called. 2385 size_t failures = VerifyHeapReferences(false); 2386 if (failures > 0) { 2387 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2388 << " failures"; 2389 } 2390 gc->SwapBitmaps(); 2391 } 2392 if (verify_pre_sweeping_rosalloc_) { 2393 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2394 } 2395} 2396 2397void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2398 // Only pause if we have to do some verification. 2399 Thread* const self = Thread::Current(); 2400 TimingLogger* const timings = &gc->GetTimings(); 2401 if (verify_system_weaks_) { 2402 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2403 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2404 mark_sweep->VerifySystemWeaks(); 2405 } 2406 if (verify_post_gc_rosalloc_) { 2407 RosAllocVerification(timings, "PostGcRosAllocVerification"); 2408 } 2409 if (verify_post_gc_heap_) { 2410 TimingLogger::ScopedSplit split("PostGcVerifyHeapReferences", timings); 2411 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2412 size_t failures = VerifyHeapReferences(); 2413 if (failures > 0) { 2414 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2415 << " failures"; 2416 } 2417 } 2418} 2419 2420void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2421 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2422 collector::GarbageCollector::ScopedPause pause(gc); 2423 PreGcVerificationPaused(gc); 2424 } 2425} 2426 2427void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2428 TimingLogger::ScopedSplit split(name, timings); 2429 for (const auto& space : continuous_spaces_) { 2430 if (space->IsRosAllocSpace()) { 2431 VLOG(heap) << name << " : " << space->GetName(); 2432 space->AsRosAllocSpace()->Verify(); 2433 } 2434 } 2435} 2436 2437collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2438 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2439 MutexLock mu(self, *gc_complete_lock_); 2440 return WaitForGcToCompleteLocked(cause, self); 2441} 2442 2443collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2444 collector::GcType last_gc_type = collector::kGcTypeNone; 2445 uint64_t wait_start = NanoTime(); 2446 while (collector_type_running_ != kCollectorTypeNone) { 2447 ATRACE_BEGIN("GC: Wait For Completion"); 2448 // We must wait, change thread state then sleep on gc_complete_cond_; 2449 gc_complete_cond_->Wait(self); 2450 last_gc_type = last_gc_type_; 2451 ATRACE_END(); 2452 } 2453 uint64_t wait_time = NanoTime() - wait_start; 2454 total_wait_time_ += wait_time; 2455 if (wait_time > long_pause_log_threshold_) { 2456 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2457 << " for cause " << cause; 2458 } 2459 return last_gc_type; 2460} 2461 2462void Heap::DumpForSigQuit(std::ostream& os) { 2463 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2464 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2465 DumpGcPerformanceInfo(os); 2466} 2467 2468size_t Heap::GetPercentFree() { 2469 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2470} 2471 2472void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2473 if (max_allowed_footprint > GetMaxMemory()) { 2474 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2475 << PrettySize(GetMaxMemory()); 2476 max_allowed_footprint = GetMaxMemory(); 2477 } 2478 max_allowed_footprint_ = max_allowed_footprint; 2479} 2480 2481bool Heap::IsMovableObject(const mirror::Object* obj) const { 2482 if (kMovingCollector) { 2483 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2484 if (space != nullptr) { 2485 // TODO: Check large object? 2486 return space->CanMoveObjects(); 2487 } 2488 } 2489 return false; 2490} 2491 2492void Heap::UpdateMaxNativeFootprint() { 2493 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2494 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2495 size_t target_size = native_size / GetTargetHeapUtilization(); 2496 if (target_size > native_size + max_free_) { 2497 target_size = native_size + max_free_; 2498 } else if (target_size < native_size + min_free_) { 2499 target_size = native_size + min_free_; 2500 } 2501 native_footprint_gc_watermark_ = target_size; 2502 native_footprint_limit_ = 2 * target_size - native_size; 2503} 2504 2505collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2506 for (const auto& collector : garbage_collectors_) { 2507 if (collector->GetCollectorType() == collector_type_ && 2508 collector->GetGcType() == gc_type) { 2509 return collector; 2510 } 2511 } 2512 return nullptr; 2513} 2514 2515double Heap::HeapGrowthMultiplier() const { 2516 // If we don't care about pause times we are background, so return 1.0. 2517 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2518 return 1.0; 2519 } 2520 return foreground_heap_growth_multiplier_; 2521} 2522 2523void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2524 // We know what our utilization is at this moment. 2525 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2526 const uint64_t bytes_allocated = GetBytesAllocated(); 2527 last_gc_size_ = bytes_allocated; 2528 last_gc_time_ns_ = NanoTime(); 2529 uint64_t target_size; 2530 collector::GcType gc_type = collector_ran->GetGcType(); 2531 if (gc_type != collector::kGcTypeSticky) { 2532 // Grow the heap for non sticky GC. 2533 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2534 // foreground. 2535 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2536 CHECK_GE(delta, 0); 2537 target_size = bytes_allocated + delta * multiplier; 2538 target_size = std::min(target_size, 2539 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2540 target_size = std::max(target_size, 2541 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2542 native_need_to_run_finalization_ = true; 2543 next_gc_type_ = collector::kGcTypeSticky; 2544 } else { 2545 collector::GcType non_sticky_gc_type = 2546 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2547 // Find what the next non sticky collector will be. 2548 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2549 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2550 // do another sticky collection next. 2551 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2552 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2553 // if the sticky GC throughput always remained >= the full/partial throughput. 2554 if (collector_ran->GetEstimatedLastIterationThroughput() * kStickyGcThroughputAdjustment >= 2555 non_sticky_collector->GetEstimatedMeanThroughput() && 2556 non_sticky_collector->GetIterations() > 0 && 2557 bytes_allocated <= max_allowed_footprint_) { 2558 next_gc_type_ = collector::kGcTypeSticky; 2559 } else { 2560 next_gc_type_ = non_sticky_gc_type; 2561 } 2562 // If we have freed enough memory, shrink the heap back down. 2563 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2564 target_size = bytes_allocated + max_free_; 2565 } else { 2566 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2567 } 2568 } 2569 if (!ignore_max_footprint_) { 2570 SetIdealFootprint(target_size); 2571 if (IsGcConcurrent()) { 2572 // Calculate when to perform the next ConcurrentGC. 2573 // Calculate the estimated GC duration. 2574 const double gc_duration_seconds = NsToMs(collector_ran->GetDurationNs()) / 1000.0; 2575 // Estimate how many remaining bytes we will have when we need to start the next GC. 2576 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2577 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2578 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2579 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2580 // A never going to happen situation that from the estimated allocation rate we will exceed 2581 // the applications entire footprint with the given estimated allocation rate. Schedule 2582 // another GC nearly straight away. 2583 remaining_bytes = kMinConcurrentRemainingBytes; 2584 } 2585 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2586 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2587 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2588 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2589 // right away. 2590 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2591 static_cast<size_t>(bytes_allocated)); 2592 } 2593 } 2594} 2595 2596void Heap::ClearGrowthLimit() { 2597 growth_limit_ = capacity_; 2598 non_moving_space_->ClearGrowthLimit(); 2599} 2600 2601void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2602 ScopedObjectAccess soa(self); 2603 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2604 jvalue args[1]; 2605 args[0].l = arg.get(); 2606 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2607 // Restore object in case it gets moved. 2608 *object = soa.Decode<mirror::Object*>(arg.get()); 2609} 2610 2611void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2612 StackHandleScope<1> hs(self); 2613 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2614 RequestConcurrentGC(self); 2615} 2616 2617void Heap::RequestConcurrentGC(Thread* self) { 2618 // Make sure that we can do a concurrent GC. 2619 Runtime* runtime = Runtime::Current(); 2620 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2621 self->IsHandlingStackOverflow()) { 2622 return; 2623 } 2624 // We already have a request pending, no reason to start more until we update 2625 // concurrent_start_bytes_. 2626 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2627 JNIEnv* env = self->GetJniEnv(); 2628 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2629 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2630 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2631 WellKnownClasses::java_lang_Daemons_requestGC); 2632 CHECK(!env->ExceptionCheck()); 2633} 2634 2635void Heap::ConcurrentGC(Thread* self) { 2636 if (Runtime::Current()->IsShuttingDown(self)) { 2637 return; 2638 } 2639 // Wait for any GCs currently running to finish. 2640 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2641 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2642 // instead. E.g. can't do partial, so do full instead. 2643 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2644 collector::kGcTypeNone) { 2645 for (collector::GcType gc_type : gc_plan_) { 2646 // Attempt to run the collector, if we succeed, we are done. 2647 if (gc_type > next_gc_type_ && 2648 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2649 break; 2650 } 2651 } 2652 } 2653 } 2654} 2655 2656void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2657 Thread* self = Thread::Current(); 2658 { 2659 MutexLock mu(self, *heap_trim_request_lock_); 2660 if (desired_collector_type_ == desired_collector_type) { 2661 return; 2662 } 2663 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2664 desired_collector_type_ = desired_collector_type; 2665 } 2666 SignalHeapTrimDaemon(self); 2667} 2668 2669void Heap::RequestHeapTrim() { 2670 // Request a heap trim only if we do not currently care about pause times. 2671 if (CareAboutPauseTimes()) { 2672 return; 2673 } 2674 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2675 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2676 // a space it will hold its lock and can become a cause of jank. 2677 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2678 // forking. 2679 2680 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2681 // because that only marks object heads, so a large array looks like lots of empty space. We 2682 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2683 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2684 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2685 // not how much use we're making of those pages. 2686 2687 Thread* self = Thread::Current(); 2688 Runtime* runtime = Runtime::Current(); 2689 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2690 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2691 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2692 // as we don't hold the lock while requesting the trim). 2693 return; 2694 } 2695 { 2696 MutexLock mu(self, *heap_trim_request_lock_); 2697 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2698 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2699 // just yet. 2700 return; 2701 } 2702 heap_trim_request_pending_ = true; 2703 } 2704 // Notify the daemon thread which will actually do the heap trim. 2705 SignalHeapTrimDaemon(self); 2706} 2707 2708void Heap::SignalHeapTrimDaemon(Thread* self) { 2709 JNIEnv* env = self->GetJniEnv(); 2710 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2711 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2712 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2713 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2714 CHECK(!env->ExceptionCheck()); 2715} 2716 2717void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2718 if (rosalloc_space_ != nullptr) { 2719 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2720 } 2721 if (bump_pointer_space_ != nullptr) { 2722 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2723 } 2724} 2725 2726void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2727 if (rosalloc_space_ != nullptr) { 2728 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2729 } 2730} 2731 2732void Heap::RevokeAllThreadLocalBuffers() { 2733 if (rosalloc_space_ != nullptr) { 2734 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2735 } 2736 if (bump_pointer_space_ != nullptr) { 2737 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2738 } 2739} 2740 2741bool Heap::IsGCRequestPending() const { 2742 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2743} 2744 2745void Heap::RunFinalization(JNIEnv* env) { 2746 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2747 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2748 CHECK(WellKnownClasses::java_lang_System != nullptr); 2749 WellKnownClasses::java_lang_System_runFinalization = 2750 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2751 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2752 } 2753 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2754 WellKnownClasses::java_lang_System_runFinalization); 2755} 2756 2757void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2758 Thread* self = ThreadForEnv(env); 2759 if (native_need_to_run_finalization_) { 2760 RunFinalization(env); 2761 UpdateMaxNativeFootprint(); 2762 native_need_to_run_finalization_ = false; 2763 } 2764 // Total number of native bytes allocated. 2765 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 2766 new_native_bytes_allocated += bytes; 2767 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 2768 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2769 collector::kGcTypeFull; 2770 2771 // The second watermark is higher than the gc watermark. If you hit this it means you are 2772 // allocating native objects faster than the GC can keep up with. 2773 if (new_native_bytes_allocated > native_footprint_limit_) { 2774 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 2775 // Just finished a GC, attempt to run finalizers. 2776 RunFinalization(env); 2777 CHECK(!env->ExceptionCheck()); 2778 } 2779 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2780 if (new_native_bytes_allocated > native_footprint_limit_) { 2781 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2782 RunFinalization(env); 2783 native_need_to_run_finalization_ = false; 2784 CHECK(!env->ExceptionCheck()); 2785 } 2786 // We have just run finalizers, update the native watermark since it is very likely that 2787 // finalizers released native managed allocations. 2788 UpdateMaxNativeFootprint(); 2789 } else if (!IsGCRequestPending()) { 2790 if (IsGcConcurrent()) { 2791 RequestConcurrentGC(self); 2792 } else { 2793 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2794 } 2795 } 2796 } 2797} 2798 2799void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2800 int expected_size, new_size; 2801 do { 2802 expected_size = native_bytes_allocated_.LoadRelaxed(); 2803 new_size = expected_size - bytes; 2804 if (UNLIKELY(new_size < 0)) { 2805 ScopedObjectAccess soa(env); 2806 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2807 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2808 "registered as allocated", bytes, expected_size).c_str()); 2809 break; 2810 } 2811 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, new_size)); 2812} 2813 2814size_t Heap::GetTotalMemory() const { 2815 size_t ret = 0; 2816 for (const auto& space : continuous_spaces_) { 2817 // Currently don't include the image space. 2818 if (!space->IsImageSpace()) { 2819 ret += space->Size(); 2820 } 2821 } 2822 for (const auto& space : discontinuous_spaces_) { 2823 if (space->IsLargeObjectSpace()) { 2824 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2825 } 2826 } 2827 return ret; 2828} 2829 2830void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2831 DCHECK(mod_union_table != nullptr); 2832 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2833} 2834 2835void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2836 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2837 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2838 c->GetDescriptor().empty()); 2839 CHECK_GE(byte_count, sizeof(mirror::Object)); 2840} 2841 2842void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2843 CHECK(remembered_set != nullptr); 2844 space::Space* space = remembered_set->GetSpace(); 2845 CHECK(space != nullptr); 2846 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 2847 remembered_sets_.Put(space, remembered_set); 2848 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 2849} 2850 2851void Heap::RemoveRememberedSet(space::Space* space) { 2852 CHECK(space != nullptr); 2853 auto it = remembered_sets_.find(space); 2854 CHECK(it != remembered_sets_.end()); 2855 remembered_sets_.erase(it); 2856 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2857} 2858 2859void Heap::ClearMarkedObjects() { 2860 // Clear all of the spaces' mark bitmaps. 2861 for (const auto& space : GetContinuousSpaces()) { 2862 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2863 if (space->GetLiveBitmap() != mark_bitmap) { 2864 mark_bitmap->Clear(); 2865 } 2866 } 2867 // Clear the marked objects in the discontinous space object sets. 2868 for (const auto& space : GetDiscontinuousSpaces()) { 2869 space->GetMarkBitmap()->Clear(); 2870 } 2871} 2872 2873} // namespace gc 2874} // namespace art 2875