heap.cc revision 4240c5112aedb174a3e1c1f071ea54e82168b130
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 allocation_rate_(0), 154 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 155 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 156 * verification is enabled, we limit the size of allocation stacks to speed up their 157 * searching. 158 */ 159 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 160 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 161 current_allocator_(kAllocatorTypeDlMalloc), 162 current_non_moving_allocator_(kAllocatorTypeNonMoving), 163 bump_pointer_space_(nullptr), 164 temp_space_(nullptr), 165 min_free_(min_free), 166 max_free_(max_free), 167 target_utilization_(target_utilization), 168 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 169 total_wait_time_(0), 170 total_allocation_time_(0), 171 verify_object_mode_(kVerifyObjectModeDisabled), 172 disable_moving_gc_count_(0), 173 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 174 use_tlab_(use_tlab) { 175 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 176 LOG(INFO) << "Heap() entering"; 177 } 178 const bool is_zygote = Runtime::Current()->IsZygote(); 179 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 180 // entrypoints. 181 if (!is_zygote) { 182 large_object_threshold_ = kDefaultLargeObjectThreshold; 183 // Background compaction is currently not supported for command line runs. 184 if (background_collector_type_ != foreground_collector_type_) { 185 VLOG(heap) << "Disabling background compaction for non zygote"; 186 background_collector_type_ = foreground_collector_type_; 187 } 188 } 189 ChangeCollector(desired_collector_type_); 190 191 live_bitmap_.reset(new accounting::HeapBitmap(this)); 192 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 193 // Requested begin for the alloc space, to follow the mapped image and oat files 194 byte* requested_alloc_space_begin = nullptr; 195 if (!image_file_name.empty()) { 196 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 197 image_instruction_set); 198 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 199 AddSpace(image_space); 200 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 201 // isn't going to get in the middle 202 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 203 CHECK_GT(oat_file_end_addr, image_space->End()); 204 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 205 } 206 if (is_zygote) { 207 // Reserve the address range before we create the non moving space to make sure bitmaps don't 208 // take it. 209 std::string error_str; 210 MemMap* mem_map = MemMap::MapAnonymous( 211 "main space", requested_alloc_space_begin + kNonMovingSpaceCapacity, capacity, 212 PROT_READ | PROT_WRITE, true, &error_str); 213 CHECK(mem_map != nullptr) << error_str; 214 // Non moving space is always dlmalloc since we currently don't have support for multiple 215 // rosalloc spaces. 216 non_moving_space_ = space::DlMallocSpace::Create( 217 "zygote / non moving space", initial_size, kNonMovingSpaceCapacity, kNonMovingSpaceCapacity, 218 requested_alloc_space_begin, false); 219 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 220 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 221 } else { 222 std::string error_str; 223 MemMap* mem_map = MemMap::MapAnonymous("main/non-moving space", requested_alloc_space_begin, 224 capacity, PROT_READ | PROT_WRITE, true, &error_str); 225 CHECK(mem_map != nullptr) << error_str; 226 // Create the main free list space, which doubles as the non moving space. We can do this since 227 // non zygote means that we won't have any background compaction. 228 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 229 non_moving_space_ = main_space_; 230 } 231 CHECK(non_moving_space_ != nullptr); 232 233 // We need to create the bump pointer if the foreground collector is a compacting GC. We only 234 // create the bump pointer space if we are not a moving foreground collector but have a moving 235 // background collector since the heap transition code will create the temp space by recycling 236 // the bitmap from the main space. 237 if (kMovingCollector && 238 (IsMovingGc(foreground_collector_type_) || IsMovingGc(background_collector_type_))) { 239 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 240 // Divide by 2 for a temporary fix for reducing virtual memory usage. 241 const size_t bump_pointer_space_capacity = capacity / 2; 242 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 243 bump_pointer_space_capacity, nullptr); 244 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 245 AddSpace(bump_pointer_space_); 246 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 247 bump_pointer_space_capacity, nullptr); 248 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 249 AddSpace(temp_space_); 250 } 251 if (non_moving_space_ != main_space_) { 252 AddSpace(non_moving_space_); 253 } 254 if (main_space_ != nullptr) { 255 AddSpace(main_space_); 256 } 257 258 // Allocate the large object space. 259 if (kUseFreeListSpaceForLOS) { 260 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 261 } else { 262 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 263 } 264 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 265 AddSpace(large_object_space_); 266 267 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 268 CHECK(!continuous_spaces_.empty()); 269 270 // Relies on the spaces being sorted. 271 byte* heap_begin = continuous_spaces_.front()->Begin(); 272 byte* heap_end = continuous_spaces_.back()->Limit(); 273 size_t heap_capacity = heap_end - heap_begin; 274 275 // Allocate the card table. 276 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 277 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 278 279 // Card cache for now since it makes it easier for us to update the references to the copying 280 // spaces. 281 accounting::ModUnionTable* mod_union_table = 282 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 283 GetImageSpace()); 284 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 285 AddModUnionTable(mod_union_table); 286 287 if (collector::SemiSpace::kUseRememberedSet) { 288 accounting::RememberedSet* non_moving_space_rem_set = 289 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 290 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 291 AddRememberedSet(non_moving_space_rem_set); 292 if (main_space_ != nullptr && main_space_ != non_moving_space_) { 293 accounting::RememberedSet* main_space_rem_set = 294 new accounting::RememberedSet("Main space remembered set", this, main_space_); 295 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 296 AddRememberedSet(main_space_rem_set); 297 } 298 } 299 300 // TODO: Count objects in the image space here. 301 num_bytes_allocated_.StoreRelaxed(0); 302 303 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 304 kDefaultMarkStackSize)); 305 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 306 allocation_stack_.reset(accounting::ObjectStack::Create( 307 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 308 live_stack_.reset(accounting::ObjectStack::Create( 309 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 310 311 // It's still too early to take a lock because there are no threads yet, but we can create locks 312 // now. We don't create it earlier to make it clear that you can't use locks during heap 313 // initialization. 314 gc_complete_lock_ = new Mutex("GC complete lock"); 315 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 316 *gc_complete_lock_)); 317 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 318 last_gc_size_ = GetBytesAllocated(); 319 320 if (ignore_max_footprint_) { 321 SetIdealFootprint(std::numeric_limits<size_t>::max()); 322 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 323 } 324 CHECK_NE(max_allowed_footprint_, 0U); 325 326 // Create our garbage collectors. 327 for (size_t i = 0; i < 2; ++i) { 328 const bool concurrent = i != 0; 329 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 330 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 331 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 332 } 333 if (kMovingCollector) { 334 // TODO: Clean this up. 335 bool generational = foreground_collector_type_ == kCollectorTypeGSS; 336 semi_space_collector_ = new collector::SemiSpace(this, generational, 337 generational ? "generational" : ""); 338 garbage_collectors_.push_back(semi_space_collector_); 339 340 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 341 garbage_collectors_.push_back(concurrent_copying_collector_); 342 } 343 344 if (running_on_valgrind_) { 345 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 346 } 347 348 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 349 LOG(INFO) << "Heap() exiting"; 350 } 351} 352 353void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 354 size_t capacity) { 355 // Is background compaction is enabled? 356 bool can_move_objects = IsMovingGc(background_collector_type_) != 357 IsMovingGc(foreground_collector_type_); 358 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 359 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 360 // from the main space to the zygote space. If background compaction is enabled, always pass in 361 // that we can move objets. 362 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 363 // After the zygote we want this to be false if we don't have background compaction enabled so 364 // that getting primitive array elements is faster. 365 can_move_objects = !have_zygote_space_; 366 } 367 if (kUseRosAlloc) { 368 rosalloc_space_ = space::RosAllocSpace::CreateFromMemMap( 369 mem_map, "main rosalloc space", kDefaultStartingSize, initial_size, growth_limit, capacity, 370 low_memory_mode_, can_move_objects); 371 main_space_ = rosalloc_space_; 372 CHECK(main_space_ != nullptr) << "Failed to create rosalloc space"; 373 } else { 374 dlmalloc_space_ = space::DlMallocSpace::CreateFromMemMap( 375 mem_map, "main dlmalloc space", kDefaultStartingSize, initial_size, growth_limit, capacity, 376 can_move_objects); 377 main_space_ = dlmalloc_space_; 378 CHECK(main_space_ != nullptr) << "Failed to create dlmalloc space"; 379 } 380 main_space_->SetFootprintLimit(main_space_->Capacity()); 381 VLOG(heap) << "Created main space " << main_space_; 382} 383 384void Heap::ChangeAllocator(AllocatorType allocator) { 385 if (current_allocator_ != allocator) { 386 // These two allocators are only used internally and don't have any entrypoints. 387 CHECK_NE(allocator, kAllocatorTypeLOS); 388 CHECK_NE(allocator, kAllocatorTypeNonMoving); 389 current_allocator_ = allocator; 390 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 391 SetQuickAllocEntryPointsAllocator(current_allocator_); 392 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 393 } 394} 395 396void Heap::DisableCompaction() { 397 if (IsMovingGc(foreground_collector_type_)) { 398 foreground_collector_type_ = kCollectorTypeCMS; 399 } 400 if (IsMovingGc(background_collector_type_)) { 401 background_collector_type_ = foreground_collector_type_; 402 } 403 TransitionCollector(foreground_collector_type_); 404} 405 406std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 407 if (!IsValidContinuousSpaceObjectAddress(klass)) { 408 return StringPrintf("<non heap address klass %p>", klass); 409 } 410 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 411 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 412 std::string result("["); 413 result += SafeGetClassDescriptor(component_type); 414 return result; 415 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 416 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 417 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 418 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 419 } else { 420 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 421 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 422 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 423 } 424 const DexFile* dex_file = dex_cache->GetDexFile(); 425 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 426 if (class_def_idx == DexFile::kDexNoIndex16) { 427 return "<class def not found>"; 428 } 429 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 430 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 431 return dex_file->GetTypeDescriptor(type_id); 432 } 433} 434 435std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 436 if (obj == nullptr) { 437 return "null"; 438 } 439 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 440 if (klass == nullptr) { 441 return "(class=null)"; 442 } 443 std::string result(SafeGetClassDescriptor(klass)); 444 if (obj->IsClass()) { 445 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 446 } 447 return result; 448} 449 450void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 451 if (obj == nullptr) { 452 stream << "(obj=null)"; 453 return; 454 } 455 if (IsAligned<kObjectAlignment>(obj)) { 456 space::Space* space = nullptr; 457 // Don't use find space since it only finds spaces which actually contain objects instead of 458 // spaces which may contain objects (e.g. cleared bump pointer spaces). 459 for (const auto& cur_space : continuous_spaces_) { 460 if (cur_space->HasAddress(obj)) { 461 space = cur_space; 462 break; 463 } 464 } 465 // Unprotect all the spaces. 466 for (const auto& space : continuous_spaces_) { 467 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 468 } 469 stream << "Object " << obj; 470 if (space != nullptr) { 471 stream << " in space " << *space; 472 } 473 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 474 stream << "\nclass=" << klass; 475 if (klass != nullptr) { 476 stream << " type= " << SafePrettyTypeOf(obj); 477 } 478 // Re-protect the address we faulted on. 479 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 480 } 481} 482 483bool Heap::IsCompilingBoot() const { 484 for (const auto& space : continuous_spaces_) { 485 if (space->IsImageSpace() || space->IsZygoteSpace()) { 486 return false; 487 } 488 } 489 return true; 490} 491 492bool Heap::HasImageSpace() const { 493 for (const auto& space : continuous_spaces_) { 494 if (space->IsImageSpace()) { 495 return true; 496 } 497 } 498 return false; 499} 500 501void Heap::IncrementDisableMovingGC(Thread* self) { 502 // Need to do this holding the lock to prevent races where the GC is about to run / running when 503 // we attempt to disable it. 504 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 505 MutexLock mu(self, *gc_complete_lock_); 506 ++disable_moving_gc_count_; 507 if (IsMovingGc(collector_type_running_)) { 508 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 509 } 510} 511 512void Heap::DecrementDisableMovingGC(Thread* self) { 513 MutexLock mu(self, *gc_complete_lock_); 514 CHECK_GE(disable_moving_gc_count_, 0U); 515 --disable_moving_gc_count_; 516} 517 518void Heap::UpdateProcessState(ProcessState process_state) { 519 if (process_state_ != process_state) { 520 process_state_ = process_state; 521 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 522 // Start at index 1 to avoid "is always false" warning. 523 // Have iteration 1 always transition the collector. 524 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 525 ? foreground_collector_type_ : background_collector_type_); 526 usleep(kCollectorTransitionStressWait); 527 } 528 if (process_state_ == kProcessStateJankPerceptible) { 529 // Transition back to foreground right away to prevent jank. 530 RequestCollectorTransition(foreground_collector_type_, 0); 531 } else { 532 // Don't delay for debug builds since we may want to stress test the GC. 533 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 534 kCollectorTransitionWait); 535 } 536 } 537} 538 539void Heap::CreateThreadPool() { 540 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 541 if (num_threads != 0) { 542 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 543 } 544} 545 546void Heap::VisitObjects(ObjectCallback callback, void* arg) { 547 Thread* self = Thread::Current(); 548 // GCs can move objects, so don't allow this. 549 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 550 if (bump_pointer_space_ != nullptr) { 551 // Visit objects in bump pointer space. 552 bump_pointer_space_->Walk(callback, arg); 553 } 554 // TODO: Switch to standard begin and end to use ranged a based loop. 555 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 556 it < end; ++it) { 557 mirror::Object* obj = *it; 558 if (obj != nullptr && obj->GetClass() != nullptr) { 559 // Avoid the race condition caused by the object not yet being written into the allocation 560 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 561 // there can be nulls on the allocation stack. 562 callback(obj, arg); 563 } 564 } 565 GetLiveBitmap()->Walk(callback, arg); 566 self->EndAssertNoThreadSuspension(old_cause); 567} 568 569void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 570 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 571 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 572 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 573 // TODO: Generalize this to n bitmaps? 574 if (space1 == nullptr) { 575 DCHECK(space2 != nullptr); 576 space1 = space2; 577 } 578 if (space2 == nullptr) { 579 DCHECK(space1 != nullptr); 580 space2 = space1; 581 } 582 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 583 large_object_space_->GetLiveBitmap(), stack); 584} 585 586void Heap::DeleteThreadPool() { 587 thread_pool_.reset(nullptr); 588} 589 590void Heap::AddSpace(space::Space* space) { 591 DCHECK(space != nullptr); 592 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 593 if (space->IsContinuousSpace()) { 594 DCHECK(!space->IsDiscontinuousSpace()); 595 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 596 // Continuous spaces don't necessarily have bitmaps. 597 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 598 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 599 if (live_bitmap != nullptr) { 600 DCHECK(mark_bitmap != nullptr); 601 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 602 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 603 } 604 continuous_spaces_.push_back(continuous_space); 605 // Ensure that spaces remain sorted in increasing order of start address. 606 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 607 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 608 return a->Begin() < b->Begin(); 609 }); 610 } else { 611 DCHECK(space->IsDiscontinuousSpace()); 612 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 613 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 614 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 615 discontinuous_spaces_.push_back(discontinuous_space); 616 } 617 if (space->IsAllocSpace()) { 618 alloc_spaces_.push_back(space->AsAllocSpace()); 619 } 620} 621 622void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 623 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 624 if (continuous_space->IsDlMallocSpace()) { 625 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 626 } else if (continuous_space->IsRosAllocSpace()) { 627 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 628 } 629} 630 631void Heap::RemoveSpace(space::Space* space) { 632 DCHECK(space != nullptr); 633 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 634 if (space->IsContinuousSpace()) { 635 DCHECK(!space->IsDiscontinuousSpace()); 636 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 637 // Continuous spaces don't necessarily have bitmaps. 638 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 639 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 640 if (live_bitmap != nullptr) { 641 DCHECK(mark_bitmap != nullptr); 642 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 643 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 644 } 645 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 646 DCHECK(it != continuous_spaces_.end()); 647 continuous_spaces_.erase(it); 648 } else { 649 DCHECK(space->IsDiscontinuousSpace()); 650 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 651 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 652 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 653 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 654 discontinuous_space); 655 DCHECK(it != discontinuous_spaces_.end()); 656 discontinuous_spaces_.erase(it); 657 } 658 if (space->IsAllocSpace()) { 659 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 660 DCHECK(it != alloc_spaces_.end()); 661 alloc_spaces_.erase(it); 662 } 663} 664 665void Heap::RegisterGCAllocation(size_t bytes) { 666 if (this != nullptr) { 667 gc_memory_overhead_.FetchAndAddSequentiallyConsistent(bytes); 668 } 669} 670 671void Heap::RegisterGCDeAllocation(size_t bytes) { 672 if (this != nullptr) { 673 gc_memory_overhead_.FetchAndSubSequentiallyConsistent(bytes); 674 } 675} 676 677void Heap::DumpGcPerformanceInfo(std::ostream& os) { 678 // Dump cumulative timings. 679 os << "Dumping cumulative Gc timings\n"; 680 uint64_t total_duration = 0; 681 // Dump cumulative loggers for each GC type. 682 uint64_t total_paused_time = 0; 683 for (auto& collector : garbage_collectors_) { 684 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 685 const size_t iterations = logger.GetIterations(); 686 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 687 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 688 os << ConstDumpable<CumulativeLogger>(logger); 689 const uint64_t total_ns = logger.GetTotalNs(); 690 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 691 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 692 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 693 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 694 Histogram<uint64_t>::CumulativeData cumulative_data; 695 pause_histogram.CreateHistogram(&cumulative_data); 696 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 697 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 698 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 699 << collector->GetName() << " freed: " << freed_objects 700 << " objects with total size " << PrettySize(freed_bytes) << "\n" 701 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 702 << PrettySize(freed_bytes / seconds) << "/s\n"; 703 total_duration += total_ns; 704 total_paused_time += total_pause_ns; 705 } 706 collector->ResetMeasurements(); 707 } 708 uint64_t allocation_time = 709 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 710 if (total_duration != 0) { 711 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 712 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 713 os << "Mean GC size throughput: " 714 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 715 os << "Mean GC object throughput: " 716 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 717 } 718 size_t total_objects_allocated = GetObjectsAllocatedEver(); 719 os << "Total number of allocations: " << total_objects_allocated << "\n"; 720 size_t total_bytes_allocated = GetBytesAllocatedEver(); 721 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 722 if (kMeasureAllocationTime) { 723 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 724 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 725 << "\n"; 726 } 727 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 728 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 729 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_.LoadRelaxed(); 730 BaseMutex::DumpAll(os); 731} 732 733Heap::~Heap() { 734 VLOG(heap) << "Starting ~Heap()"; 735 STLDeleteElements(&garbage_collectors_); 736 // If we don't reset then the mark stack complains in its destructor. 737 allocation_stack_->Reset(); 738 live_stack_->Reset(); 739 STLDeleteValues(&mod_union_tables_); 740 STLDeleteValues(&remembered_sets_); 741 STLDeleteElements(&continuous_spaces_); 742 STLDeleteElements(&discontinuous_spaces_); 743 delete gc_complete_lock_; 744 delete heap_trim_request_lock_; 745 VLOG(heap) << "Finished ~Heap()"; 746} 747 748space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 749 bool fail_ok) const { 750 for (const auto& space : continuous_spaces_) { 751 if (space->Contains(obj)) { 752 return space; 753 } 754 } 755 if (!fail_ok) { 756 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 757 } 758 return NULL; 759} 760 761space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 762 bool fail_ok) const { 763 for (const auto& space : discontinuous_spaces_) { 764 if (space->Contains(obj)) { 765 return space; 766 } 767 } 768 if (!fail_ok) { 769 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 770 } 771 return NULL; 772} 773 774space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 775 space::Space* result = FindContinuousSpaceFromObject(obj, true); 776 if (result != NULL) { 777 return result; 778 } 779 return FindDiscontinuousSpaceFromObject(obj, true); 780} 781 782space::ImageSpace* Heap::GetImageSpace() const { 783 for (const auto& space : continuous_spaces_) { 784 if (space->IsImageSpace()) { 785 return space->AsImageSpace(); 786 } 787 } 788 return NULL; 789} 790 791static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 792 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 793 if (used_bytes < chunk_size) { 794 size_t chunk_free_bytes = chunk_size - used_bytes; 795 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 796 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 797 } 798} 799 800void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 801 std::ostringstream oss; 802 size_t total_bytes_free = GetFreeMemory(); 803 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 804 << " free bytes"; 805 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 806 if (!large_object_allocation && total_bytes_free >= byte_count) { 807 size_t max_contiguous_allocation = 0; 808 for (const auto& space : continuous_spaces_) { 809 if (space->IsMallocSpace()) { 810 // To allow the Walk/InspectAll() to exclusively-lock the mutator 811 // lock, temporarily release the shared access to the mutator 812 // lock here by transitioning to the suspended state. 813 Locks::mutator_lock_->AssertSharedHeld(self); 814 self->TransitionFromRunnableToSuspended(kSuspended); 815 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 816 self->TransitionFromSuspendedToRunnable(); 817 Locks::mutator_lock_->AssertSharedHeld(self); 818 } 819 } 820 oss << "; failed due to fragmentation (largest possible contiguous allocation " 821 << max_contiguous_allocation << " bytes)"; 822 } 823 self->ThrowOutOfMemoryError(oss.str().c_str()); 824} 825 826void Heap::DoPendingTransitionOrTrim() { 827 Thread* self = Thread::Current(); 828 CollectorType desired_collector_type; 829 // Wait until we reach the desired transition time. 830 while (true) { 831 uint64_t wait_time; 832 { 833 MutexLock mu(self, *heap_trim_request_lock_); 834 desired_collector_type = desired_collector_type_; 835 uint64_t current_time = NanoTime(); 836 if (current_time >= heap_transition_target_time_) { 837 break; 838 } 839 wait_time = heap_transition_target_time_ - current_time; 840 } 841 ScopedThreadStateChange tsc(self, kSleeping); 842 usleep(wait_time / 1000); // Usleep takes microseconds. 843 } 844 // Transition the collector if the desired collector type is not the same as the current 845 // collector type. 846 TransitionCollector(desired_collector_type); 847 if (!CareAboutPauseTimes()) { 848 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 849 // about pauses. 850 Runtime* runtime = Runtime::Current(); 851 runtime->GetThreadList()->SuspendAll(); 852 runtime->GetMonitorList()->DeflateMonitors(); 853 runtime->GetThreadList()->ResumeAll(); 854 // Do a heap trim if it is needed. 855 Trim(); 856 } 857} 858 859void Heap::Trim() { 860 Thread* self = Thread::Current(); 861 { 862 MutexLock mu(self, *heap_trim_request_lock_); 863 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 864 return; 865 } 866 last_trim_time_ = NanoTime(); 867 heap_trim_request_pending_ = false; 868 } 869 { 870 // Need to do this before acquiring the locks since we don't want to get suspended while 871 // holding any locks. 872 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 873 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 874 // trimming. 875 MutexLock mu(self, *gc_complete_lock_); 876 // Ensure there is only one GC at a time. 877 WaitForGcToCompleteLocked(kGcCauseTrim, self); 878 collector_type_running_ = kCollectorTypeHeapTrim; 879 } 880 uint64_t start_ns = NanoTime(); 881 // Trim the managed spaces. 882 uint64_t total_alloc_space_allocated = 0; 883 uint64_t total_alloc_space_size = 0; 884 uint64_t managed_reclaimed = 0; 885 for (const auto& space : continuous_spaces_) { 886 if (space->IsMallocSpace()) { 887 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 888 total_alloc_space_size += alloc_space->Size(); 889 managed_reclaimed += alloc_space->Trim(); 890 } 891 } 892 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 893 if (bump_pointer_space_ != nullptr) { 894 total_alloc_space_allocated -= bump_pointer_space_->Size(); 895 } 896 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 897 static_cast<float>(total_alloc_space_size); 898 uint64_t gc_heap_end_ns = NanoTime(); 899 // We never move things in the native heap, so we can finish the GC at this point. 900 FinishGC(self, collector::kGcTypeNone); 901 size_t native_reclaimed = 0; 902#if defined(USE_DLMALLOC) 903 // Trim the native heap. 904 dlmalloc_trim(0); 905 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 906#elif defined(USE_JEMALLOC) 907 // Jemalloc does it's own internal trimming. 908#else 909 UNIMPLEMENTED(WARNING) << "Add trimming support"; 910#endif 911 uint64_t end_ns = NanoTime(); 912 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 913 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 914 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 915 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 916 << "%."; 917} 918 919bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 920 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 921 // taking the lock. 922 if (obj == nullptr) { 923 return true; 924 } 925 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 926} 927 928bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 929 return FindContinuousSpaceFromObject(obj, true) != nullptr; 930} 931 932bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 933 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 934 return false; 935 } 936 for (const auto& space : continuous_spaces_) { 937 if (space->HasAddress(obj)) { 938 return true; 939 } 940 } 941 return false; 942} 943 944bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 945 bool search_live_stack, bool sorted) { 946 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 947 return false; 948 } 949 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 950 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 951 if (obj == klass) { 952 // This case happens for java.lang.Class. 953 return true; 954 } 955 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 956 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 957 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 958 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 959 return temp_space_->Contains(obj); 960 } 961 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 962 space::DiscontinuousSpace* d_space = nullptr; 963 if (c_space != nullptr) { 964 if (c_space->GetLiveBitmap()->Test(obj)) { 965 return true; 966 } 967 } else { 968 d_space = FindDiscontinuousSpaceFromObject(obj, true); 969 if (d_space != nullptr) { 970 if (d_space->GetLiveBitmap()->Test(obj)) { 971 return true; 972 } 973 } 974 } 975 // This is covering the allocation/live stack swapping that is done without mutators suspended. 976 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 977 if (i > 0) { 978 NanoSleep(MsToNs(10)); 979 } 980 if (search_allocation_stack) { 981 if (sorted) { 982 if (allocation_stack_->ContainsSorted(obj)) { 983 return true; 984 } 985 } else if (allocation_stack_->Contains(obj)) { 986 return true; 987 } 988 } 989 990 if (search_live_stack) { 991 if (sorted) { 992 if (live_stack_->ContainsSorted(obj)) { 993 return true; 994 } 995 } else if (live_stack_->Contains(obj)) { 996 return true; 997 } 998 } 999 } 1000 // We need to check the bitmaps again since there is a race where we mark something as live and 1001 // then clear the stack containing it. 1002 if (c_space != nullptr) { 1003 if (c_space->GetLiveBitmap()->Test(obj)) { 1004 return true; 1005 } 1006 } else { 1007 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1008 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1009 return true; 1010 } 1011 } 1012 return false; 1013} 1014 1015void Heap::DumpSpaces(std::ostream& stream) { 1016 for (const auto& space : continuous_spaces_) { 1017 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1018 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1019 stream << space << " " << *space << "\n"; 1020 if (live_bitmap != nullptr) { 1021 stream << live_bitmap << " " << *live_bitmap << "\n"; 1022 } 1023 if (mark_bitmap != nullptr) { 1024 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1025 } 1026 } 1027 for (const auto& space : discontinuous_spaces_) { 1028 stream << space << " " << *space << "\n"; 1029 } 1030} 1031 1032void Heap::VerifyObjectBody(mirror::Object* obj) { 1033 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1034 return; 1035 } 1036 // Ignore early dawn of the universe verifications. 1037 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1038 return; 1039 } 1040 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1041 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1042 CHECK(c != nullptr) << "Null class in object " << obj; 1043 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1044 CHECK(VerifyClassClass(c)); 1045 1046 if (verify_object_mode_ > kVerifyObjectModeFast) { 1047 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1048 if (!IsLiveObjectLocked(obj)) { 1049 DumpSpaces(); 1050 LOG(FATAL) << "Object is dead: " << obj; 1051 } 1052 } 1053} 1054 1055void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1056 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1057} 1058 1059void Heap::VerifyHeap() { 1060 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1061 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1062} 1063 1064void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1065 // Use signed comparison since freed bytes can be negative when background compaction foreground 1066 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1067 // free list backed space typically increasing memory footprint due to padding and binning. 1068 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1069 // Note: This relies on 2s complement for handling negative freed_bytes. 1070 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1071 if (Runtime::Current()->HasStatsEnabled()) { 1072 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1073 thread_stats->freed_objects += freed_objects; 1074 thread_stats->freed_bytes += freed_bytes; 1075 // TODO: Do this concurrently. 1076 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1077 global_stats->freed_objects += freed_objects; 1078 global_stats->freed_bytes += freed_bytes; 1079 } 1080} 1081 1082mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1083 size_t alloc_size, size_t* bytes_allocated, 1084 size_t* usable_size, 1085 mirror::Class** klass) { 1086 bool was_default_allocator = allocator == GetCurrentAllocator(); 1087 DCHECK(klass != nullptr); 1088 StackHandleScope<1> hs(self); 1089 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1090 klass = nullptr; // Invalidate for safety. 1091 // The allocation failed. If the GC is running, block until it completes, and then retry the 1092 // allocation. 1093 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1094 if (last_gc != collector::kGcTypeNone) { 1095 // If we were the default allocator but the allocator changed while we were suspended, 1096 // abort the allocation. 1097 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1098 return nullptr; 1099 } 1100 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1101 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1102 usable_size); 1103 if (ptr != nullptr) { 1104 return ptr; 1105 } 1106 } 1107 1108 collector::GcType tried_type = next_gc_type_; 1109 const bool gc_ran = 1110 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1111 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1112 return nullptr; 1113 } 1114 if (gc_ran) { 1115 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1116 usable_size); 1117 if (ptr != nullptr) { 1118 return ptr; 1119 } 1120 } 1121 1122 // Loop through our different Gc types and try to Gc until we get enough free memory. 1123 for (collector::GcType gc_type : gc_plan_) { 1124 if (gc_type == tried_type) { 1125 continue; 1126 } 1127 // Attempt to run the collector, if we succeed, re-try the allocation. 1128 const bool gc_ran = 1129 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1130 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1131 return nullptr; 1132 } 1133 if (gc_ran) { 1134 // Did we free sufficient memory for the allocation to succeed? 1135 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1136 usable_size); 1137 if (ptr != nullptr) { 1138 return ptr; 1139 } 1140 } 1141 } 1142 // Allocations have failed after GCs; this is an exceptional state. 1143 // Try harder, growing the heap if necessary. 1144 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1145 usable_size); 1146 if (ptr != nullptr) { 1147 return ptr; 1148 } 1149 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1150 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1151 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1152 // OOME. 1153 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1154 << " allocation"; 1155 // TODO: Run finalization, but this may cause more allocations to occur. 1156 // We don't need a WaitForGcToComplete here either. 1157 DCHECK(!gc_plan_.empty()); 1158 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1159 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1160 return nullptr; 1161 } 1162 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1163 if (ptr == nullptr) { 1164 ThrowOutOfMemoryError(self, alloc_size, false); 1165 } 1166 return ptr; 1167} 1168 1169void Heap::SetTargetHeapUtilization(float target) { 1170 DCHECK_GT(target, 0.0f); // asserted in Java code 1171 DCHECK_LT(target, 1.0f); 1172 target_utilization_ = target; 1173} 1174 1175size_t Heap::GetObjectsAllocated() const { 1176 size_t total = 0; 1177 for (space::AllocSpace* space : alloc_spaces_) { 1178 total += space->GetObjectsAllocated(); 1179 } 1180 return total; 1181} 1182 1183size_t Heap::GetObjectsAllocatedEver() const { 1184 return GetObjectsFreedEver() + GetObjectsAllocated(); 1185} 1186 1187size_t Heap::GetBytesAllocatedEver() const { 1188 return GetBytesFreedEver() + GetBytesAllocated(); 1189} 1190 1191class InstanceCounter { 1192 public: 1193 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1194 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1195 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1196 } 1197 static void Callback(mirror::Object* obj, void* arg) 1198 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1199 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1200 mirror::Class* instance_class = obj->GetClass(); 1201 CHECK(instance_class != nullptr); 1202 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1203 if (instance_counter->use_is_assignable_from_) { 1204 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1205 ++instance_counter->counts_[i]; 1206 } 1207 } else if (instance_class == instance_counter->classes_[i]) { 1208 ++instance_counter->counts_[i]; 1209 } 1210 } 1211 } 1212 1213 private: 1214 const std::vector<mirror::Class*>& classes_; 1215 bool use_is_assignable_from_; 1216 uint64_t* const counts_; 1217 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1218}; 1219 1220void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1221 uint64_t* counts) { 1222 // Can't do any GC in this function since this may move classes. 1223 Thread* self = Thread::Current(); 1224 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1225 InstanceCounter counter(classes, use_is_assignable_from, counts); 1226 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1227 VisitObjects(InstanceCounter::Callback, &counter); 1228 self->EndAssertNoThreadSuspension(old_cause); 1229} 1230 1231class InstanceCollector { 1232 public: 1233 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1234 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1235 : class_(c), max_count_(max_count), instances_(instances) { 1236 } 1237 static void Callback(mirror::Object* obj, void* arg) 1238 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1239 DCHECK(arg != nullptr); 1240 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1241 mirror::Class* instance_class = obj->GetClass(); 1242 if (instance_class == instance_collector->class_) { 1243 if (instance_collector->max_count_ == 0 || 1244 instance_collector->instances_.size() < instance_collector->max_count_) { 1245 instance_collector->instances_.push_back(obj); 1246 } 1247 } 1248 } 1249 1250 private: 1251 mirror::Class* class_; 1252 uint32_t max_count_; 1253 std::vector<mirror::Object*>& instances_; 1254 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1255}; 1256 1257void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1258 std::vector<mirror::Object*>& instances) { 1259 // Can't do any GC in this function since this may move classes. 1260 Thread* self = Thread::Current(); 1261 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1262 InstanceCollector collector(c, max_count, instances); 1263 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1264 VisitObjects(&InstanceCollector::Callback, &collector); 1265 self->EndAssertNoThreadSuspension(old_cause); 1266} 1267 1268class ReferringObjectsFinder { 1269 public: 1270 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1271 std::vector<mirror::Object*>& referring_objects) 1272 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1273 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1274 } 1275 1276 static void Callback(mirror::Object* obj, void* arg) 1277 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1278 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1279 } 1280 1281 // For bitmap Visit. 1282 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1283 // annotalysis on visitors. 1284 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1285 o->VisitReferences<true>(*this, VoidFunctor()); 1286 } 1287 1288 // For Object::VisitReferences. 1289 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1290 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1291 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1292 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1293 referring_objects_.push_back(obj); 1294 } 1295 } 1296 1297 private: 1298 mirror::Object* object_; 1299 uint32_t max_count_; 1300 std::vector<mirror::Object*>& referring_objects_; 1301 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1302}; 1303 1304void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1305 std::vector<mirror::Object*>& referring_objects) { 1306 // Can't do any GC in this function since this may move the object o. 1307 Thread* self = Thread::Current(); 1308 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1309 ReferringObjectsFinder finder(o, max_count, referring_objects); 1310 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1311 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1312 self->EndAssertNoThreadSuspension(old_cause); 1313} 1314 1315void Heap::CollectGarbage(bool clear_soft_references) { 1316 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1317 // last GC will not have necessarily been cleared. 1318 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1319} 1320 1321void Heap::TransitionCollector(CollectorType collector_type) { 1322 if (collector_type == collector_type_) { 1323 return; 1324 } 1325 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1326 << " -> " << static_cast<int>(collector_type); 1327 uint64_t start_time = NanoTime(); 1328 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1329 ThreadList* tl = Runtime::Current()->GetThreadList(); 1330 Thread* self = Thread::Current(); 1331 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1332 Locks::mutator_lock_->AssertNotHeld(self); 1333 const bool copying_transition = 1334 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1335 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1336 // compacting_gc_disable_count_, this should rarely occurs). 1337 for (;;) { 1338 { 1339 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1340 MutexLock mu(self, *gc_complete_lock_); 1341 // Ensure there is only one GC at a time. 1342 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1343 // If someone else beat us to it and changed the collector before we could, exit. 1344 // This is safe to do before the suspend all since we set the collector_type_running_ before 1345 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1346 // then it would get blocked on WaitForGcToCompleteLocked. 1347 if (collector_type == collector_type_) { 1348 return; 1349 } 1350 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1351 if (!copying_transition || disable_moving_gc_count_ == 0) { 1352 // TODO: Not hard code in semi-space collector? 1353 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1354 break; 1355 } 1356 } 1357 usleep(1000); 1358 } 1359 if (Runtime::Current()->IsShuttingDown(self)) { 1360 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1361 // cause objects to get finalized. 1362 FinishGC(self, collector::kGcTypeNone); 1363 return; 1364 } 1365 tl->SuspendAll(); 1366 switch (collector_type) { 1367 case kCollectorTypeSS: 1368 // Fall-through. 1369 case kCollectorTypeGSS: { 1370 if (!IsMovingGc(collector_type_)) { 1371 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1372 // pointer space last transition it will be protected. 1373 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1374 Compact(bump_pointer_space_, main_space_); 1375 // Remove the main space so that we don't try to trim it, this doens't work for debug 1376 // builds since RosAlloc attempts to read the magic number from a protected page. 1377 // TODO: Clean this up by getting rid of the remove_as_default parameter. 1378 RemoveSpace(main_space_); 1379 } 1380 break; 1381 } 1382 case kCollectorTypeMS: 1383 // Fall through. 1384 case kCollectorTypeCMS: { 1385 if (IsMovingGc(collector_type_)) { 1386 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1387 AddSpace(main_space_); 1388 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1389 Compact(main_space_, bump_pointer_space_); 1390 } 1391 break; 1392 } 1393 default: { 1394 LOG(FATAL) << "Attempted to transition to invalid collector type " 1395 << static_cast<size_t>(collector_type); 1396 break; 1397 } 1398 } 1399 ChangeCollector(collector_type); 1400 tl->ResumeAll(); 1401 // Can't call into java code with all threads suspended. 1402 reference_processor_.EnqueueClearedReferences(); 1403 uint64_t duration = NanoTime() - start_time; 1404 GrowForUtilization(semi_space_collector_); 1405 FinishGC(self, collector::kGcTypeFull); 1406 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1407 int32_t delta_allocated = before_allocated - after_allocated; 1408 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1409 << PrettyDuration(duration) << " saved at least " << PrettySize(delta_allocated); 1410} 1411 1412void Heap::ChangeCollector(CollectorType collector_type) { 1413 // TODO: Only do this with all mutators suspended to avoid races. 1414 if (collector_type != collector_type_) { 1415 collector_type_ = collector_type; 1416 gc_plan_.clear(); 1417 switch (collector_type_) { 1418 case kCollectorTypeCC: // Fall-through. 1419 case kCollectorTypeSS: // Fall-through. 1420 case kCollectorTypeGSS: { 1421 gc_plan_.push_back(collector::kGcTypeFull); 1422 if (use_tlab_) { 1423 ChangeAllocator(kAllocatorTypeTLAB); 1424 } else { 1425 ChangeAllocator(kAllocatorTypeBumpPointer); 1426 } 1427 break; 1428 } 1429 case kCollectorTypeMS: { 1430 gc_plan_.push_back(collector::kGcTypeSticky); 1431 gc_plan_.push_back(collector::kGcTypePartial); 1432 gc_plan_.push_back(collector::kGcTypeFull); 1433 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1434 break; 1435 } 1436 case kCollectorTypeCMS: { 1437 gc_plan_.push_back(collector::kGcTypeSticky); 1438 gc_plan_.push_back(collector::kGcTypePartial); 1439 gc_plan_.push_back(collector::kGcTypeFull); 1440 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1441 break; 1442 } 1443 default: { 1444 LOG(FATAL) << "Unimplemented"; 1445 } 1446 } 1447 if (IsGcConcurrent()) { 1448 concurrent_start_bytes_ = 1449 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1450 } else { 1451 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1452 } 1453 } 1454} 1455 1456// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1457class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1458 public: 1459 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1460 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1461 } 1462 1463 void BuildBins(space::ContinuousSpace* space) { 1464 bin_live_bitmap_ = space->GetLiveBitmap(); 1465 bin_mark_bitmap_ = space->GetMarkBitmap(); 1466 BinContext context; 1467 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1468 context.collector_ = this; 1469 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1470 // Note: This requires traversing the space in increasing order of object addresses. 1471 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1472 // Add the last bin which spans after the last object to the end of the space. 1473 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1474 } 1475 1476 private: 1477 struct BinContext { 1478 uintptr_t prev_; // The end of the previous object. 1479 ZygoteCompactingCollector* collector_; 1480 }; 1481 // Maps from bin sizes to locations. 1482 std::multimap<size_t, uintptr_t> bins_; 1483 // Live bitmap of the space which contains the bins. 1484 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1485 // Mark bitmap of the space which contains the bins. 1486 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1487 1488 static void Callback(mirror::Object* obj, void* arg) 1489 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1490 DCHECK(arg != nullptr); 1491 BinContext* context = reinterpret_cast<BinContext*>(arg); 1492 ZygoteCompactingCollector* collector = context->collector_; 1493 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1494 size_t bin_size = object_addr - context->prev_; 1495 // Add the bin consisting of the end of the previous object to the start of the current object. 1496 collector->AddBin(bin_size, context->prev_); 1497 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1498 } 1499 1500 void AddBin(size_t size, uintptr_t position) { 1501 if (size != 0) { 1502 bins_.insert(std::make_pair(size, position)); 1503 } 1504 } 1505 1506 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1507 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1508 // allocator. 1509 return false; 1510 } 1511 1512 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1513 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1514 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1515 mirror::Object* forward_address; 1516 // Find the smallest bin which we can move obj in. 1517 auto it = bins_.lower_bound(object_size); 1518 if (it == bins_.end()) { 1519 // No available space in the bins, place it in the target space instead (grows the zygote 1520 // space). 1521 size_t bytes_allocated; 1522 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1523 if (to_space_live_bitmap_ != nullptr) { 1524 to_space_live_bitmap_->Set(forward_address); 1525 } else { 1526 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1527 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1528 } 1529 } else { 1530 size_t size = it->first; 1531 uintptr_t pos = it->second; 1532 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1533 forward_address = reinterpret_cast<mirror::Object*>(pos); 1534 // Set the live and mark bits so that sweeping system weaks works properly. 1535 bin_live_bitmap_->Set(forward_address); 1536 bin_mark_bitmap_->Set(forward_address); 1537 DCHECK_GE(size, object_size); 1538 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1539 } 1540 // Copy the object over to its new location. 1541 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1542 if (kUseBakerOrBrooksReadBarrier) { 1543 obj->AssertReadBarrierPointer(); 1544 if (kUseBrooksReadBarrier) { 1545 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1546 forward_address->SetReadBarrierPointer(forward_address); 1547 } 1548 forward_address->AssertReadBarrierPointer(); 1549 } 1550 return forward_address; 1551 } 1552}; 1553 1554void Heap::UnBindBitmaps() { 1555 for (const auto& space : GetContinuousSpaces()) { 1556 if (space->IsContinuousMemMapAllocSpace()) { 1557 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1558 if (alloc_space->HasBoundBitmaps()) { 1559 alloc_space->UnBindBitmaps(); 1560 } 1561 } 1562 } 1563} 1564 1565void Heap::PreZygoteFork() { 1566 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1567 Thread* self = Thread::Current(); 1568 MutexLock mu(self, zygote_creation_lock_); 1569 // Try to see if we have any Zygote spaces. 1570 if (have_zygote_space_) { 1571 return; 1572 } 1573 VLOG(heap) << "Starting PreZygoteFork"; 1574 // Trim the pages at the end of the non moving space. 1575 non_moving_space_->Trim(); 1576 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1577 // there. 1578 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1579 // Change the collector to the post zygote one. 1580 if (kCompactZygote) { 1581 DCHECK(semi_space_collector_ != nullptr); 1582 // Temporarily disable rosalloc verification because the zygote 1583 // compaction will mess up the rosalloc internal metadata. 1584 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1585 ZygoteCompactingCollector zygote_collector(this); 1586 zygote_collector.BuildBins(non_moving_space_); 1587 // Create a new bump pointer space which we will compact into. 1588 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1589 non_moving_space_->Limit()); 1590 // Compact the bump pointer space to a new zygote bump pointer space. 1591 bool reset_main_space = false; 1592 if (IsMovingGc(collector_type_)) { 1593 zygote_collector.SetFromSpace(bump_pointer_space_); 1594 } else { 1595 CHECK(main_space_ != nullptr); 1596 // Copy from the main space. 1597 zygote_collector.SetFromSpace(main_space_); 1598 reset_main_space = true; 1599 } 1600 zygote_collector.SetToSpace(&target_space); 1601 zygote_collector.SetSwapSemiSpaces(false); 1602 zygote_collector.Run(kGcCauseCollectorTransition, false); 1603 if (reset_main_space) { 1604 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1605 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1606 MemMap* mem_map = main_space_->ReleaseMemMap(); 1607 RemoveSpace(main_space_); 1608 delete main_space_; 1609 main_space_ = nullptr; 1610 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1611 AddSpace(main_space_); 1612 } else { 1613 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1614 } 1615 if (temp_space_ != nullptr) { 1616 CHECK(temp_space_->IsEmpty()); 1617 } 1618 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1619 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1620 // Update the end and write out image. 1621 non_moving_space_->SetEnd(target_space.End()); 1622 non_moving_space_->SetLimit(target_space.Limit()); 1623 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1624 } 1625 ChangeCollector(foreground_collector_type_); 1626 // Save the old space so that we can remove it after we complete creating the zygote space. 1627 space::MallocSpace* old_alloc_space = non_moving_space_; 1628 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1629 // the remaining available space. 1630 // Remove the old space before creating the zygote space since creating the zygote space sets 1631 // the old alloc space's bitmaps to nullptr. 1632 RemoveSpace(old_alloc_space); 1633 if (collector::SemiSpace::kUseRememberedSet) { 1634 // Sanity bound check. 1635 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1636 // Remove the remembered set for the now zygote space (the old 1637 // non-moving space). Note now that we have compacted objects into 1638 // the zygote space, the data in the remembered set is no longer 1639 // needed. The zygote space will instead have a mod-union table 1640 // from this point on. 1641 RemoveRememberedSet(old_alloc_space); 1642 } 1643 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1644 low_memory_mode_, 1645 &non_moving_space_); 1646 delete old_alloc_space; 1647 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1648 AddSpace(zygote_space); 1649 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1650 AddSpace(non_moving_space_); 1651 have_zygote_space_ = true; 1652 // Enable large object space allocations. 1653 large_object_threshold_ = kDefaultLargeObjectThreshold; 1654 // Create the zygote space mod union table. 1655 accounting::ModUnionTable* mod_union_table = 1656 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1657 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1658 AddModUnionTable(mod_union_table); 1659 if (collector::SemiSpace::kUseRememberedSet) { 1660 // Add a new remembered set for the post-zygote non-moving space. 1661 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1662 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1663 non_moving_space_); 1664 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1665 << "Failed to create post-zygote non-moving space remembered set"; 1666 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1667 } 1668} 1669 1670void Heap::FlushAllocStack() { 1671 MarkAllocStackAsLive(allocation_stack_.get()); 1672 allocation_stack_->Reset(); 1673} 1674 1675void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 1676 accounting::ContinuousSpaceBitmap* bitmap2, 1677 accounting::LargeObjectBitmap* large_objects, 1678 accounting::ObjectStack* stack) { 1679 DCHECK(bitmap1 != nullptr); 1680 DCHECK(bitmap2 != nullptr); 1681 mirror::Object** limit = stack->End(); 1682 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1683 const mirror::Object* obj = *it; 1684 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1685 if (bitmap1->HasAddress(obj)) { 1686 bitmap1->Set(obj); 1687 } else if (bitmap2->HasAddress(obj)) { 1688 bitmap2->Set(obj); 1689 } else { 1690 large_objects->Set(obj); 1691 } 1692 } 1693 } 1694} 1695 1696void Heap::SwapSemiSpaces() { 1697 CHECK(bump_pointer_space_ != nullptr); 1698 CHECK(temp_space_ != nullptr); 1699 std::swap(bump_pointer_space_, temp_space_); 1700} 1701 1702void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1703 space::ContinuousMemMapAllocSpace* source_space) { 1704 CHECK(kMovingCollector); 1705 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1706 if (target_space != source_space) { 1707 // Don't swap spaces since this isn't a typical semi space collection. 1708 semi_space_collector_->SetSwapSemiSpaces(false); 1709 semi_space_collector_->SetFromSpace(source_space); 1710 semi_space_collector_->SetToSpace(target_space); 1711 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1712 } 1713} 1714 1715collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1716 bool clear_soft_references) { 1717 Thread* self = Thread::Current(); 1718 Runtime* runtime = Runtime::Current(); 1719 // If the heap can't run the GC, silently fail and return that no GC was run. 1720 switch (gc_type) { 1721 case collector::kGcTypePartial: { 1722 if (!have_zygote_space_) { 1723 return collector::kGcTypeNone; 1724 } 1725 break; 1726 } 1727 default: { 1728 // Other GC types don't have any special cases which makes them not runnable. The main case 1729 // here is full GC. 1730 } 1731 } 1732 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1733 Locks::mutator_lock_->AssertNotHeld(self); 1734 if (self->IsHandlingStackOverflow()) { 1735 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1736 } 1737 bool compacting_gc; 1738 { 1739 gc_complete_lock_->AssertNotHeld(self); 1740 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1741 MutexLock mu(self, *gc_complete_lock_); 1742 // Ensure there is only one GC at a time. 1743 WaitForGcToCompleteLocked(gc_cause, self); 1744 compacting_gc = IsMovingGc(collector_type_); 1745 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1746 if (compacting_gc && disable_moving_gc_count_ != 0) { 1747 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1748 return collector::kGcTypeNone; 1749 } 1750 collector_type_running_ = collector_type_; 1751 } 1752 1753 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1754 ++runtime->GetStats()->gc_for_alloc_count; 1755 ++self->GetStats()->gc_for_alloc_count; 1756 } 1757 uint64_t gc_start_time_ns = NanoTime(); 1758 uint64_t gc_start_size = GetBytesAllocated(); 1759 // Approximate allocation rate in bytes / second. 1760 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1761 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1762 if (LIKELY(ms_delta != 0)) { 1763 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1764 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1765 } 1766 1767 DCHECK_LT(gc_type, collector::kGcTypeMax); 1768 DCHECK_NE(gc_type, collector::kGcTypeNone); 1769 1770 collector::GarbageCollector* collector = nullptr; 1771 // TODO: Clean this up. 1772 if (compacting_gc) { 1773 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1774 current_allocator_ == kAllocatorTypeTLAB); 1775 if (collector_type_ == kCollectorTypeSS || collector_type_ == kCollectorTypeGSS) { 1776 gc_type = semi_space_collector_->GetGcType(); 1777 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1778 semi_space_collector_->SetToSpace(temp_space_); 1779 collector = semi_space_collector_; 1780 semi_space_collector_->SetSwapSemiSpaces(true); 1781 } else if (collector_type_ == kCollectorTypeCC) { 1782 gc_type = concurrent_copying_collector_->GetGcType(); 1783 collector = concurrent_copying_collector_; 1784 } else { 1785 LOG(FATAL) << "Unreachable - invalid collector type " << static_cast<size_t>(collector_type_); 1786 } 1787 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1788 CHECK(temp_space_->IsEmpty()); 1789 gc_type = collector::kGcTypeFull; 1790 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1791 current_allocator_ == kAllocatorTypeDlMalloc) { 1792 collector = FindCollectorByGcType(gc_type); 1793 } else { 1794 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1795 } 1796 CHECK(collector != nullptr) 1797 << "Could not find garbage collector with collector_type=" 1798 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1799 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1800 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1801 total_objects_freed_ever_ += collector->GetFreedObjects(); 1802 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1803 RequestHeapTrim(); 1804 // Enqueue cleared references. 1805 reference_processor_.EnqueueClearedReferences(); 1806 // Grow the heap so that we know when to perform the next GC. 1807 GrowForUtilization(collector); 1808 const size_t duration = collector->GetDurationNs(); 1809 const std::vector<uint64_t>& pause_times = collector->GetPauseTimes(); 1810 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 1811 // (mutator time blocked >= long_pause_log_threshold_). 1812 bool log_gc = gc_cause == kGcCauseExplicit; 1813 if (!log_gc && CareAboutPauseTimes()) { 1814 // GC for alloc pauses the allocating thread, so consider it as a pause. 1815 log_gc = duration > long_gc_log_threshold_ || 1816 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1817 for (uint64_t pause : pause_times) { 1818 log_gc = log_gc || pause >= long_pause_log_threshold_; 1819 } 1820 } 1821 if (log_gc) { 1822 const size_t percent_free = GetPercentFree(); 1823 const size_t current_heap_size = GetBytesAllocated(); 1824 const size_t total_memory = GetTotalMemory(); 1825 std::ostringstream pause_string; 1826 for (size_t i = 0; i < pause_times.size(); ++i) { 1827 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 1828 << ((i != pause_times.size() - 1) ? "," : ""); 1829 } 1830 LOG(INFO) << gc_cause << " " << collector->GetName() 1831 << " GC freed " << collector->GetFreedObjects() << "(" 1832 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1833 << collector->GetFreedLargeObjects() << "(" 1834 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1835 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1836 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1837 << " total " << PrettyDuration((duration / 1000) * 1000); 1838 VLOG(heap) << ConstDumpable<TimingLogger>(collector->GetTimings()); 1839 } 1840 FinishGC(self, gc_type); 1841 ATRACE_END(); 1842 1843 // Inform DDMS that a GC completed. 1844 Dbg::GcDidFinish(); 1845 return gc_type; 1846} 1847 1848void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1849 MutexLock mu(self, *gc_complete_lock_); 1850 collector_type_running_ = kCollectorTypeNone; 1851 if (gc_type != collector::kGcTypeNone) { 1852 last_gc_type_ = gc_type; 1853 } 1854 // Wake anyone who may have been waiting for the GC to complete. 1855 gc_complete_cond_->Broadcast(self); 1856} 1857 1858static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1859 RootType /*root_type*/) { 1860 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1861 if (*root == obj) { 1862 LOG(INFO) << "Object " << obj << " is a root"; 1863 } 1864} 1865 1866class ScanVisitor { 1867 public: 1868 void operator()(const mirror::Object* obj) const { 1869 LOG(ERROR) << "Would have rescanned object " << obj; 1870 } 1871}; 1872 1873// Verify a reference from an object. 1874class VerifyReferenceVisitor { 1875 public: 1876 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 1877 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1878 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 1879 1880 size_t GetFailureCount() const { 1881 return fail_count_->LoadSequentiallyConsistent(); 1882 } 1883 1884 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1885 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1886 if (verify_referent_) { 1887 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 1888 } 1889 } 1890 1891 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1892 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1893 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 1894 } 1895 1896 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1897 return heap_->IsLiveObjectLocked(obj, true, false, true); 1898 } 1899 1900 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 1901 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1902 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1903 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 1904 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 1905 << " thread_id= " << thread_id << " root_type= " << root_type; 1906 } 1907 } 1908 1909 private: 1910 // TODO: Fix the no thread safety analysis. 1911 // Returns false on failure. 1912 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1913 NO_THREAD_SAFETY_ANALYSIS { 1914 if (ref == nullptr || IsLive(ref)) { 1915 // Verify that the reference is live. 1916 return true; 1917 } 1918 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 1919 // Print message on only on first failure to prevent spam. 1920 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1921 } 1922 if (obj != nullptr) { 1923 // Only do this part for non roots. 1924 accounting::CardTable* card_table = heap_->GetCardTable(); 1925 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1926 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1927 byte* card_addr = card_table->CardFromAddr(obj); 1928 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1929 << offset << "\n card value = " << static_cast<int>(*card_addr); 1930 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1931 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1932 } else { 1933 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1934 } 1935 1936 // Attmept to find the class inside of the recently freed objects. 1937 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1938 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1939 space::MallocSpace* space = ref_space->AsMallocSpace(); 1940 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1941 if (ref_class != nullptr) { 1942 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1943 << PrettyClass(ref_class); 1944 } else { 1945 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1946 } 1947 } 1948 1949 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1950 ref->GetClass()->IsClass()) { 1951 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1952 } else { 1953 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1954 << ") is not a valid heap address"; 1955 } 1956 1957 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1958 void* cover_begin = card_table->AddrFromCard(card_addr); 1959 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1960 accounting::CardTable::kCardSize); 1961 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1962 << "-" << cover_end; 1963 accounting::ContinuousSpaceBitmap* bitmap = 1964 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1965 1966 if (bitmap == nullptr) { 1967 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1968 if (!VerifyClassClass(obj->GetClass())) { 1969 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1970 } 1971 } else { 1972 // Print out how the object is live. 1973 if (bitmap->Test(obj)) { 1974 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1975 } 1976 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1977 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1978 } 1979 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1980 LOG(ERROR) << "Object " << obj << " found in live stack"; 1981 } 1982 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1983 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1984 } 1985 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1986 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1987 } 1988 // Attempt to see if the card table missed the reference. 1989 ScanVisitor scan_visitor; 1990 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1991 card_table->Scan(bitmap, byte_cover_begin, 1992 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1993 } 1994 1995 // Search to see if any of the roots reference our object. 1996 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1997 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 1998 1999 // Search to see if any of the roots reference our reference. 2000 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2001 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2002 } 2003 return false; 2004 } 2005 2006 Heap* const heap_; 2007 Atomic<size_t>* const fail_count_; 2008 const bool verify_referent_; 2009}; 2010 2011// Verify all references within an object, for use with HeapBitmap::Visit. 2012class VerifyObjectVisitor { 2013 public: 2014 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2015 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2016 } 2017 2018 void operator()(mirror::Object* obj) const 2019 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2020 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2021 // be live or else how did we find it in the live bitmap? 2022 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2023 // The class doesn't count as a reference but we should verify it anyways. 2024 obj->VisitReferences<true>(visitor, visitor); 2025 } 2026 2027 static void VisitCallback(mirror::Object* obj, void* arg) 2028 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2029 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2030 visitor->operator()(obj); 2031 } 2032 2033 size_t GetFailureCount() const { 2034 return fail_count_->LoadSequentiallyConsistent(); 2035 } 2036 2037 private: 2038 Heap* const heap_; 2039 Atomic<size_t>* const fail_count_; 2040 const bool verify_referent_; 2041}; 2042 2043void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2044 // Slow path, the allocation stack push back must have already failed. 2045 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2046 do { 2047 // TODO: Add handle VerifyObject. 2048 StackHandleScope<1> hs(self); 2049 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2050 // Push our object into the reserve region of the allocaiton stack. This is only required due 2051 // to heap verification requiring that roots are live (either in the live bitmap or in the 2052 // allocation stack). 2053 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2054 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2055 } while (!allocation_stack_->AtomicPushBack(*obj)); 2056} 2057 2058void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2059 // Slow path, the allocation stack push back must have already failed. 2060 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2061 mirror::Object** start_address; 2062 mirror::Object** end_address; 2063 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2064 &end_address)) { 2065 // TODO: Add handle VerifyObject. 2066 StackHandleScope<1> hs(self); 2067 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2068 // Push our object into the reserve region of the allocaiton stack. This is only required due 2069 // to heap verification requiring that roots are live (either in the live bitmap or in the 2070 // allocation stack). 2071 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2072 // Push into the reserve allocation stack. 2073 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2074 } 2075 self->SetThreadLocalAllocationStack(start_address, end_address); 2076 // Retry on the new thread-local allocation stack. 2077 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2078} 2079 2080// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2081size_t Heap::VerifyHeapReferences(bool verify_referents) { 2082 Thread* self = Thread::Current(); 2083 Locks::mutator_lock_->AssertExclusiveHeld(self); 2084 // Lets sort our allocation stacks so that we can efficiently binary search them. 2085 allocation_stack_->Sort(); 2086 live_stack_->Sort(); 2087 // Since we sorted the allocation stack content, need to revoke all 2088 // thread-local allocation stacks. 2089 RevokeAllThreadLocalAllocationStacks(self); 2090 Atomic<size_t> fail_count_(0); 2091 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2092 // Verify objects in the allocation stack since these will be objects which were: 2093 // 1. Allocated prior to the GC (pre GC verification). 2094 // 2. Allocated during the GC (pre sweep GC verification). 2095 // We don't want to verify the objects in the live stack since they themselves may be 2096 // pointing to dead objects if they are not reachable. 2097 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2098 // Verify the roots: 2099 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2100 if (visitor.GetFailureCount() > 0) { 2101 // Dump mod-union tables. 2102 for (const auto& table_pair : mod_union_tables_) { 2103 accounting::ModUnionTable* mod_union_table = table_pair.second; 2104 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2105 } 2106 // Dump remembered sets. 2107 for (const auto& table_pair : remembered_sets_) { 2108 accounting::RememberedSet* remembered_set = table_pair.second; 2109 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2110 } 2111 DumpSpaces(); 2112 } 2113 return visitor.GetFailureCount(); 2114} 2115 2116class VerifyReferenceCardVisitor { 2117 public: 2118 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2119 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2120 Locks::heap_bitmap_lock_) 2121 : heap_(heap), failed_(failed) { 2122 } 2123 2124 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2125 // annotalysis on visitors. 2126 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2127 NO_THREAD_SAFETY_ANALYSIS { 2128 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2129 // Filter out class references since changing an object's class does not mark the card as dirty. 2130 // Also handles large objects, since the only reference they hold is a class reference. 2131 if (ref != nullptr && !ref->IsClass()) { 2132 accounting::CardTable* card_table = heap_->GetCardTable(); 2133 // If the object is not dirty and it is referencing something in the live stack other than 2134 // class, then it must be on a dirty card. 2135 if (!card_table->AddrIsInCardTable(obj)) { 2136 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2137 *failed_ = true; 2138 } else if (!card_table->IsDirty(obj)) { 2139 // TODO: Check mod-union tables. 2140 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2141 // kCardDirty - 1 if it didnt get touched since we aged it. 2142 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2143 if (live_stack->ContainsSorted(ref)) { 2144 if (live_stack->ContainsSorted(obj)) { 2145 LOG(ERROR) << "Object " << obj << " found in live stack"; 2146 } 2147 if (heap_->GetLiveBitmap()->Test(obj)) { 2148 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2149 } 2150 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2151 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2152 2153 // Print which field of the object is dead. 2154 if (!obj->IsObjectArray()) { 2155 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2156 CHECK(klass != NULL); 2157 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2158 : klass->GetIFields(); 2159 CHECK(fields != NULL); 2160 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2161 mirror::ArtField* cur = fields->Get(i); 2162 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2163 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2164 << PrettyField(cur); 2165 break; 2166 } 2167 } 2168 } else { 2169 mirror::ObjectArray<mirror::Object>* object_array = 2170 obj->AsObjectArray<mirror::Object>(); 2171 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2172 if (object_array->Get(i) == ref) { 2173 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2174 } 2175 } 2176 } 2177 2178 *failed_ = true; 2179 } 2180 } 2181 } 2182 } 2183 2184 private: 2185 Heap* const heap_; 2186 bool* const failed_; 2187}; 2188 2189class VerifyLiveStackReferences { 2190 public: 2191 explicit VerifyLiveStackReferences(Heap* heap) 2192 : heap_(heap), 2193 failed_(false) {} 2194 2195 void operator()(mirror::Object* obj) const 2196 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2197 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2198 obj->VisitReferences<true>(visitor, VoidFunctor()); 2199 } 2200 2201 bool Failed() const { 2202 return failed_; 2203 } 2204 2205 private: 2206 Heap* const heap_; 2207 bool failed_; 2208}; 2209 2210bool Heap::VerifyMissingCardMarks() { 2211 Thread* self = Thread::Current(); 2212 Locks::mutator_lock_->AssertExclusiveHeld(self); 2213 2214 // We need to sort the live stack since we binary search it. 2215 live_stack_->Sort(); 2216 // Since we sorted the allocation stack content, need to revoke all 2217 // thread-local allocation stacks. 2218 RevokeAllThreadLocalAllocationStacks(self); 2219 VerifyLiveStackReferences visitor(this); 2220 GetLiveBitmap()->Visit(visitor); 2221 2222 // We can verify objects in the live stack since none of these should reference dead objects. 2223 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2224 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2225 visitor(*it); 2226 } 2227 } 2228 2229 if (visitor.Failed()) { 2230 DumpSpaces(); 2231 return false; 2232 } 2233 return true; 2234} 2235 2236void Heap::SwapStacks(Thread* self) { 2237 if (kUseThreadLocalAllocationStack) { 2238 live_stack_->AssertAllZero(); 2239 } 2240 allocation_stack_.swap(live_stack_); 2241} 2242 2243void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2244 // This must be called only during the pause. 2245 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2246 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2247 MutexLock mu2(self, *Locks::thread_list_lock_); 2248 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2249 for (Thread* t : thread_list) { 2250 t->RevokeThreadLocalAllocationStack(); 2251 } 2252} 2253 2254void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2255 if (kIsDebugBuild) { 2256 if (bump_pointer_space_ != nullptr) { 2257 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2258 } 2259 } 2260} 2261 2262accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2263 auto it = mod_union_tables_.find(space); 2264 if (it == mod_union_tables_.end()) { 2265 return nullptr; 2266 } 2267 return it->second; 2268} 2269 2270accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2271 auto it = remembered_sets_.find(space); 2272 if (it == remembered_sets_.end()) { 2273 return nullptr; 2274 } 2275 return it->second; 2276} 2277 2278void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2279 // Clear cards and keep track of cards cleared in the mod-union table. 2280 for (const auto& space : continuous_spaces_) { 2281 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2282 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2283 if (table != nullptr) { 2284 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2285 "ImageModUnionClearCards"; 2286 TimingLogger::ScopedSplit split(name, &timings); 2287 table->ClearCards(); 2288 } else if (use_rem_sets && rem_set != nullptr) { 2289 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2290 << static_cast<int>(collector_type_); 2291 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2292 rem_set->ClearCards(); 2293 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2294 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2295 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2296 // were dirty before the GC started. 2297 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2298 // -> clean(cleaning thread). 2299 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2300 // roots and then we scan / update mod union tables after. We will always scan either card. 2301 // If we end up with the non aged card, we scan it it in the pause. 2302 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2303 } 2304 } 2305} 2306 2307static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2308} 2309 2310void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2311 Thread* const self = Thread::Current(); 2312 TimingLogger* const timings = &gc->GetTimings(); 2313 if (verify_pre_gc_heap_) { 2314 TimingLogger::ScopedSplit split("PreGcVerifyHeapReferences", timings); 2315 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2316 size_t failures = VerifyHeapReferences(); 2317 if (failures > 0) { 2318 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2319 << " failures"; 2320 } 2321 } 2322 // Check that all objects which reference things in the live stack are on dirty cards. 2323 if (verify_missing_card_marks_) { 2324 TimingLogger::ScopedSplit split("PreGcVerifyMissingCardMarks", timings); 2325 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2326 SwapStacks(self); 2327 // Sort the live stack so that we can quickly binary search it later. 2328 if (!VerifyMissingCardMarks()) { 2329 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2330 } 2331 SwapStacks(self); 2332 } 2333 if (verify_mod_union_table_) { 2334 TimingLogger::ScopedSplit split("PreGcVerifyModUnionTables", timings); 2335 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2336 for (const auto& table_pair : mod_union_tables_) { 2337 accounting::ModUnionTable* mod_union_table = table_pair.second; 2338 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2339 mod_union_table->Verify(); 2340 } 2341 } 2342} 2343 2344void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2345 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2346 collector::GarbageCollector::ScopedPause pause(gc); 2347 PreGcVerificationPaused(gc); 2348 } 2349} 2350 2351void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2352 // TODO: Add a new runtime option for this? 2353 if (verify_pre_gc_rosalloc_) { 2354 RosAllocVerification(&gc->GetTimings(), "PreGcRosAllocVerification"); 2355 } 2356} 2357 2358void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2359 Thread* const self = Thread::Current(); 2360 TimingLogger* const timings = &gc->GetTimings(); 2361 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2362 // reachable objects. 2363 if (verify_pre_sweeping_heap_) { 2364 TimingLogger::ScopedSplit split("PostSweepingVerifyHeapReferences", timings); 2365 CHECK_NE(self->GetState(), kRunnable); 2366 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2367 // Swapping bound bitmaps does nothing. 2368 gc->SwapBitmaps(); 2369 // Pass in false since concurrent reference processing can mean that the reference referents 2370 // may point to dead objects at the point which PreSweepingGcVerification is called. 2371 size_t failures = VerifyHeapReferences(false); 2372 if (failures > 0) { 2373 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2374 << " failures"; 2375 } 2376 gc->SwapBitmaps(); 2377 } 2378 if (verify_pre_sweeping_rosalloc_) { 2379 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2380 } 2381} 2382 2383void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2384 // Only pause if we have to do some verification. 2385 Thread* const self = Thread::Current(); 2386 TimingLogger* const timings = &gc->GetTimings(); 2387 if (verify_system_weaks_) { 2388 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2389 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2390 mark_sweep->VerifySystemWeaks(); 2391 } 2392 if (verify_post_gc_rosalloc_) { 2393 RosAllocVerification(timings, "PostGcRosAllocVerification"); 2394 } 2395 if (verify_post_gc_heap_) { 2396 TimingLogger::ScopedSplit split("PostGcVerifyHeapReferences", timings); 2397 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2398 size_t failures = VerifyHeapReferences(); 2399 if (failures > 0) { 2400 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2401 << " failures"; 2402 } 2403 } 2404} 2405 2406void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2407 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2408 collector::GarbageCollector::ScopedPause pause(gc); 2409 PreGcVerificationPaused(gc); 2410 } 2411} 2412 2413void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2414 TimingLogger::ScopedSplit split(name, timings); 2415 for (const auto& space : continuous_spaces_) { 2416 if (space->IsRosAllocSpace()) { 2417 VLOG(heap) << name << " : " << space->GetName(); 2418 space->AsRosAllocSpace()->Verify(); 2419 } 2420 } 2421} 2422 2423collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2424 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2425 MutexLock mu(self, *gc_complete_lock_); 2426 return WaitForGcToCompleteLocked(cause, self); 2427} 2428 2429collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2430 collector::GcType last_gc_type = collector::kGcTypeNone; 2431 uint64_t wait_start = NanoTime(); 2432 while (collector_type_running_ != kCollectorTypeNone) { 2433 ATRACE_BEGIN("GC: Wait For Completion"); 2434 // We must wait, change thread state then sleep on gc_complete_cond_; 2435 gc_complete_cond_->Wait(self); 2436 last_gc_type = last_gc_type_; 2437 ATRACE_END(); 2438 } 2439 uint64_t wait_time = NanoTime() - wait_start; 2440 total_wait_time_ += wait_time; 2441 if (wait_time > long_pause_log_threshold_) { 2442 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2443 << " for cause " << cause; 2444 } 2445 return last_gc_type; 2446} 2447 2448void Heap::DumpForSigQuit(std::ostream& os) { 2449 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2450 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2451 DumpGcPerformanceInfo(os); 2452} 2453 2454size_t Heap::GetPercentFree() { 2455 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2456} 2457 2458void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2459 if (max_allowed_footprint > GetMaxMemory()) { 2460 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2461 << PrettySize(GetMaxMemory()); 2462 max_allowed_footprint = GetMaxMemory(); 2463 } 2464 max_allowed_footprint_ = max_allowed_footprint; 2465} 2466 2467bool Heap::IsMovableObject(const mirror::Object* obj) const { 2468 if (kMovingCollector) { 2469 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2470 if (space != nullptr) { 2471 // TODO: Check large object? 2472 return space->CanMoveObjects(); 2473 } 2474 } 2475 return false; 2476} 2477 2478void Heap::UpdateMaxNativeFootprint() { 2479 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2480 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2481 size_t target_size = native_size / GetTargetHeapUtilization(); 2482 if (target_size > native_size + max_free_) { 2483 target_size = native_size + max_free_; 2484 } else if (target_size < native_size + min_free_) { 2485 target_size = native_size + min_free_; 2486 } 2487 native_footprint_gc_watermark_ = target_size; 2488 native_footprint_limit_ = 2 * target_size - native_size; 2489} 2490 2491collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2492 for (const auto& collector : garbage_collectors_) { 2493 if (collector->GetCollectorType() == collector_type_ && 2494 collector->GetGcType() == gc_type) { 2495 return collector; 2496 } 2497 } 2498 return nullptr; 2499} 2500 2501double Heap::HeapGrowthMultiplier() const { 2502 // If we don't care about pause times we are background, so return 1.0. 2503 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2504 return 1.0; 2505 } 2506 return foreground_heap_growth_multiplier_; 2507} 2508 2509void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2510 // We know what our utilization is at this moment. 2511 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2512 const uint64_t bytes_allocated = GetBytesAllocated(); 2513 last_gc_size_ = bytes_allocated; 2514 last_gc_time_ns_ = NanoTime(); 2515 uint64_t target_size; 2516 collector::GcType gc_type = collector_ran->GetGcType(); 2517 if (gc_type != collector::kGcTypeSticky) { 2518 // Grow the heap for non sticky GC. 2519 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2520 // foreground. 2521 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2522 CHECK_GE(delta, 0); 2523 target_size = bytes_allocated + delta * multiplier; 2524 target_size = std::min(target_size, 2525 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2526 target_size = std::max(target_size, 2527 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2528 native_need_to_run_finalization_ = true; 2529 next_gc_type_ = collector::kGcTypeSticky; 2530 } else { 2531 collector::GcType non_sticky_gc_type = 2532 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2533 // Find what the next non sticky collector will be. 2534 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2535 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2536 // do another sticky collection next. 2537 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2538 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2539 // if the sticky GC throughput always remained >= the full/partial throughput. 2540 if (collector_ran->GetEstimatedLastIterationThroughput() * kStickyGcThroughputAdjustment >= 2541 non_sticky_collector->GetEstimatedMeanThroughput() && 2542 non_sticky_collector->GetIterations() > 0 && 2543 bytes_allocated <= max_allowed_footprint_) { 2544 next_gc_type_ = collector::kGcTypeSticky; 2545 } else { 2546 next_gc_type_ = non_sticky_gc_type; 2547 } 2548 // If we have freed enough memory, shrink the heap back down. 2549 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2550 target_size = bytes_allocated + max_free_; 2551 } else { 2552 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2553 } 2554 } 2555 if (!ignore_max_footprint_) { 2556 SetIdealFootprint(target_size); 2557 if (IsGcConcurrent()) { 2558 // Calculate when to perform the next ConcurrentGC. 2559 // Calculate the estimated GC duration. 2560 const double gc_duration_seconds = NsToMs(collector_ran->GetDurationNs()) / 1000.0; 2561 // Estimate how many remaining bytes we will have when we need to start the next GC. 2562 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2563 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2564 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2565 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2566 // A never going to happen situation that from the estimated allocation rate we will exceed 2567 // the applications entire footprint with the given estimated allocation rate. Schedule 2568 // another GC nearly straight away. 2569 remaining_bytes = kMinConcurrentRemainingBytes; 2570 } 2571 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2572 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2573 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2574 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2575 // right away. 2576 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2577 static_cast<size_t>(bytes_allocated)); 2578 } 2579 } 2580} 2581 2582void Heap::ClearGrowthLimit() { 2583 growth_limit_ = capacity_; 2584 non_moving_space_->ClearGrowthLimit(); 2585} 2586 2587void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2588 ScopedObjectAccess soa(self); 2589 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2590 jvalue args[1]; 2591 args[0].l = arg.get(); 2592 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2593 // Restore object in case it gets moved. 2594 *object = soa.Decode<mirror::Object*>(arg.get()); 2595} 2596 2597void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2598 StackHandleScope<1> hs(self); 2599 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2600 RequestConcurrentGC(self); 2601} 2602 2603void Heap::RequestConcurrentGC(Thread* self) { 2604 // Make sure that we can do a concurrent GC. 2605 Runtime* runtime = Runtime::Current(); 2606 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2607 self->IsHandlingStackOverflow()) { 2608 return; 2609 } 2610 // We already have a request pending, no reason to start more until we update 2611 // concurrent_start_bytes_. 2612 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2613 JNIEnv* env = self->GetJniEnv(); 2614 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2615 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2616 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2617 WellKnownClasses::java_lang_Daemons_requestGC); 2618 CHECK(!env->ExceptionCheck()); 2619} 2620 2621void Heap::ConcurrentGC(Thread* self) { 2622 if (Runtime::Current()->IsShuttingDown(self)) { 2623 return; 2624 } 2625 // Wait for any GCs currently running to finish. 2626 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2627 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2628 // instead. E.g. can't do partial, so do full instead. 2629 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2630 collector::kGcTypeNone) { 2631 for (collector::GcType gc_type : gc_plan_) { 2632 // Attempt to run the collector, if we succeed, we are done. 2633 if (gc_type > next_gc_type_ && 2634 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2635 break; 2636 } 2637 } 2638 } 2639 } 2640} 2641 2642void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2643 Thread* self = Thread::Current(); 2644 { 2645 MutexLock mu(self, *heap_trim_request_lock_); 2646 if (desired_collector_type_ == desired_collector_type) { 2647 return; 2648 } 2649 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2650 desired_collector_type_ = desired_collector_type; 2651 } 2652 SignalHeapTrimDaemon(self); 2653} 2654 2655void Heap::RequestHeapTrim() { 2656 // Request a heap trim only if we do not currently care about pause times. 2657 if (CareAboutPauseTimes()) { 2658 return; 2659 } 2660 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2661 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2662 // a space it will hold its lock and can become a cause of jank. 2663 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2664 // forking. 2665 2666 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2667 // because that only marks object heads, so a large array looks like lots of empty space. We 2668 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2669 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2670 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2671 // not how much use we're making of those pages. 2672 2673 Thread* self = Thread::Current(); 2674 Runtime* runtime = Runtime::Current(); 2675 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2676 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2677 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2678 // as we don't hold the lock while requesting the trim). 2679 return; 2680 } 2681 { 2682 MutexLock mu(self, *heap_trim_request_lock_); 2683 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2684 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2685 // just yet. 2686 return; 2687 } 2688 heap_trim_request_pending_ = true; 2689 } 2690 // Notify the daemon thread which will actually do the heap trim. 2691 SignalHeapTrimDaemon(self); 2692} 2693 2694void Heap::SignalHeapTrimDaemon(Thread* self) { 2695 JNIEnv* env = self->GetJniEnv(); 2696 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2697 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2698 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2699 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2700 CHECK(!env->ExceptionCheck()); 2701} 2702 2703void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2704 if (rosalloc_space_ != nullptr) { 2705 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2706 } 2707 if (bump_pointer_space_ != nullptr) { 2708 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2709 } 2710} 2711 2712void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2713 if (rosalloc_space_ != nullptr) { 2714 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2715 } 2716} 2717 2718void Heap::RevokeAllThreadLocalBuffers() { 2719 if (rosalloc_space_ != nullptr) { 2720 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2721 } 2722 if (bump_pointer_space_ != nullptr) { 2723 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2724 } 2725} 2726 2727bool Heap::IsGCRequestPending() const { 2728 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2729} 2730 2731void Heap::RunFinalization(JNIEnv* env) { 2732 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2733 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2734 CHECK(WellKnownClasses::java_lang_System != nullptr); 2735 WellKnownClasses::java_lang_System_runFinalization = 2736 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2737 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2738 } 2739 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2740 WellKnownClasses::java_lang_System_runFinalization); 2741} 2742 2743void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2744 Thread* self = ThreadForEnv(env); 2745 if (native_need_to_run_finalization_) { 2746 RunFinalization(env); 2747 UpdateMaxNativeFootprint(); 2748 native_need_to_run_finalization_ = false; 2749 } 2750 // Total number of native bytes allocated. 2751 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 2752 new_native_bytes_allocated += bytes; 2753 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 2754 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2755 collector::kGcTypeFull; 2756 2757 // The second watermark is higher than the gc watermark. If you hit this it means you are 2758 // allocating native objects faster than the GC can keep up with. 2759 if (new_native_bytes_allocated > native_footprint_limit_) { 2760 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 2761 // Just finished a GC, attempt to run finalizers. 2762 RunFinalization(env); 2763 CHECK(!env->ExceptionCheck()); 2764 } 2765 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2766 if (new_native_bytes_allocated > native_footprint_limit_) { 2767 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2768 RunFinalization(env); 2769 native_need_to_run_finalization_ = false; 2770 CHECK(!env->ExceptionCheck()); 2771 } 2772 // We have just run finalizers, update the native watermark since it is very likely that 2773 // finalizers released native managed allocations. 2774 UpdateMaxNativeFootprint(); 2775 } else if (!IsGCRequestPending()) { 2776 if (IsGcConcurrent()) { 2777 RequestConcurrentGC(self); 2778 } else { 2779 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2780 } 2781 } 2782 } 2783} 2784 2785void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2786 int expected_size, new_size; 2787 do { 2788 expected_size = native_bytes_allocated_.LoadRelaxed(); 2789 new_size = expected_size - bytes; 2790 if (UNLIKELY(new_size < 0)) { 2791 ScopedObjectAccess soa(env); 2792 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2793 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2794 "registered as allocated", bytes, expected_size).c_str()); 2795 break; 2796 } 2797 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, new_size)); 2798} 2799 2800size_t Heap::GetTotalMemory() const { 2801 size_t ret = 0; 2802 for (const auto& space : continuous_spaces_) { 2803 // Currently don't include the image space. 2804 if (!space->IsImageSpace()) { 2805 ret += space->Size(); 2806 } 2807 } 2808 for (const auto& space : discontinuous_spaces_) { 2809 if (space->IsLargeObjectSpace()) { 2810 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2811 } 2812 } 2813 return ret; 2814} 2815 2816void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2817 DCHECK(mod_union_table != nullptr); 2818 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2819} 2820 2821void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2822 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2823 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2824 c->GetDescriptor().empty()); 2825 CHECK_GE(byte_count, sizeof(mirror::Object)); 2826} 2827 2828void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2829 CHECK(remembered_set != nullptr); 2830 space::Space* space = remembered_set->GetSpace(); 2831 CHECK(space != nullptr); 2832 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 2833 remembered_sets_.Put(space, remembered_set); 2834 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 2835} 2836 2837void Heap::RemoveRememberedSet(space::Space* space) { 2838 CHECK(space != nullptr); 2839 auto it = remembered_sets_.find(space); 2840 CHECK(it != remembered_sets_.end()); 2841 remembered_sets_.erase(it); 2842 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2843} 2844 2845void Heap::ClearMarkedObjects() { 2846 // Clear all of the spaces' mark bitmaps. 2847 for (const auto& space : GetContinuousSpaces()) { 2848 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2849 if (space->GetLiveBitmap() != mark_bitmap) { 2850 mark_bitmap->Clear(); 2851 } 2852 } 2853 // Clear the marked objects in the discontinous space object sets. 2854 for (const auto& space : GetDiscontinuousSpaces()) { 2855 space->GetMarkBitmap()->Clear(); 2856 } 2857} 2858 2859} // namespace gc 2860} // namespace art 2861