heap.cc revision a5b5c55c8585b7ce915f0c7e1f66d121a7f7a078
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_compact.h" 40#include "gc/collector/mark_sweep-inl.h" 41#include "gc/collector/partial_mark_sweep.h" 42#include "gc/collector/semi_space.h" 43#include "gc/collector/sticky_mark_sweep.h" 44#include "gc/reference_processor.h" 45#include "gc/space/bump_pointer_space.h" 46#include "gc/space/dlmalloc_space-inl.h" 47#include "gc/space/image_space.h" 48#include "gc/space/large_object_space.h" 49#include "gc/space/rosalloc_space-inl.h" 50#include "gc/space/space-inl.h" 51#include "gc/space/zygote_space.h" 52#include "entrypoints/quick/quick_alloc_entrypoints.h" 53#include "heap-inl.h" 54#include "image.h" 55#include "mirror/art_field-inl.h" 56#include "mirror/class-inl.h" 57#include "mirror/object.h" 58#include "mirror/object-inl.h" 59#include "mirror/object_array-inl.h" 60#include "mirror/reference-inl.h" 61#include "object_utils.h" 62#include "os.h" 63#include "reflection.h" 64#include "runtime.h" 65#include "ScopedLocalRef.h" 66#include "scoped_thread_state_change.h" 67#include "handle_scope-inl.h" 68#include "thread_list.h" 69#include "well_known_classes.h" 70 71namespace art { 72 73namespace gc { 74 75static constexpr size_t kCollectorTransitionStressIterations = 0; 76static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 77static constexpr bool kGCALotMode = false; 78static constexpr size_t kGcAlotInterval = KB; 79// Minimum amount of remaining bytes before a concurrent GC is triggered. 80static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 81static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 82// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 83// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 84// threads (lower pauses, use less memory bandwidth). 85static constexpr double kStickyGcThroughputAdjustment = 1.0; 86// Whether or not we use the free list large object space. 87static constexpr bool kUseFreeListSpaceForLOS = false; 88// Whether or not we compact the zygote in PreZygoteFork. 89static constexpr bool kCompactZygote = kMovingCollector; 90static constexpr size_t kNonMovingSpaceCapacity = 64 * MB; 91// How many reserve entries are at the end of the allocation stack, these are only needed if the 92// allocation stack overflows. 93static constexpr size_t kAllocationStackReserveSize = 1024; 94// Default mark stack size in bytes. 95static const size_t kDefaultMarkStackSize = 64 * KB; 96 97Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 98 double target_utilization, double foreground_heap_growth_multiplier, size_t capacity, 99 const std::string& image_file_name, const InstructionSet image_instruction_set, 100 CollectorType foreground_collector_type, CollectorType background_collector_type, 101 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 102 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 103 bool ignore_max_footprint, bool use_tlab, 104 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 105 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 106 bool verify_post_gc_rosalloc) 107 : non_moving_space_(nullptr), 108 rosalloc_space_(nullptr), 109 dlmalloc_space_(nullptr), 110 main_space_(nullptr), 111 collector_type_(kCollectorTypeNone), 112 foreground_collector_type_(foreground_collector_type), 113 background_collector_type_(background_collector_type), 114 desired_collector_type_(foreground_collector_type_), 115 heap_trim_request_lock_(nullptr), 116 last_trim_time_(0), 117 heap_transition_or_trim_target_time_(0), 118 heap_trim_request_pending_(false), 119 parallel_gc_threads_(parallel_gc_threads), 120 conc_gc_threads_(conc_gc_threads), 121 low_memory_mode_(low_memory_mode), 122 long_pause_log_threshold_(long_pause_log_threshold), 123 long_gc_log_threshold_(long_gc_log_threshold), 124 ignore_max_footprint_(ignore_max_footprint), 125 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 126 have_zygote_space_(false), 127 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 128 collector_type_running_(kCollectorTypeNone), 129 last_gc_type_(collector::kGcTypeNone), 130 next_gc_type_(collector::kGcTypePartial), 131 capacity_(capacity), 132 growth_limit_(growth_limit), 133 max_allowed_footprint_(initial_size), 134 native_footprint_gc_watermark_(initial_size), 135 native_footprint_limit_(2 * initial_size), 136 native_need_to_run_finalization_(false), 137 // Initially assume we perceive jank in case the process state is never updated. 138 process_state_(kProcessStateJankPerceptible), 139 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 140 total_bytes_freed_ever_(0), 141 total_objects_freed_ever_(0), 142 num_bytes_allocated_(0), 143 native_bytes_allocated_(0), 144 gc_memory_overhead_(0), 145 verify_missing_card_marks_(false), 146 verify_system_weaks_(false), 147 verify_pre_gc_heap_(verify_pre_gc_heap), 148 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 149 verify_post_gc_heap_(verify_post_gc_heap), 150 verify_mod_union_table_(false), 151 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 152 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 153 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 154 last_gc_time_ns_(NanoTime()), 155 allocation_rate_(0), 156 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 157 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 158 * verification is enabled, we limit the size of allocation stacks to speed up their 159 * searching. 160 */ 161 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 162 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 163 current_allocator_(kAllocatorTypeDlMalloc), 164 current_non_moving_allocator_(kAllocatorTypeNonMoving), 165 bump_pointer_space_(nullptr), 166 temp_space_(nullptr), 167 min_free_(min_free), 168 max_free_(max_free), 169 target_utilization_(target_utilization), 170 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 171 total_wait_time_(0), 172 total_allocation_time_(0), 173 verify_object_mode_(kVerifyObjectModeDisabled), 174 disable_moving_gc_count_(0), 175 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 176 use_tlab_(use_tlab) { 177 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 178 LOG(INFO) << "Heap() entering"; 179 } 180 const bool is_zygote = Runtime::Current()->IsZygote(); 181 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 182 // entrypoints. 183 if (!is_zygote) { 184 large_object_threshold_ = kDefaultLargeObjectThreshold; 185 // Background compaction is currently not supported for command line runs. 186 if (background_collector_type_ != foreground_collector_type_) { 187 VLOG(heap) << "Disabling background compaction for non zygote"; 188 background_collector_type_ = foreground_collector_type_; 189 } 190 } 191 ChangeCollector(desired_collector_type_); 192 193 live_bitmap_.reset(new accounting::HeapBitmap(this)); 194 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 195 // Requested begin for the alloc space, to follow the mapped image and oat files 196 byte* requested_alloc_space_begin = nullptr; 197 if (!image_file_name.empty()) { 198 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 199 image_instruction_set); 200 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 201 AddSpace(image_space); 202 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 203 // isn't going to get in the middle 204 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 205 CHECK_GT(oat_file_end_addr, image_space->End()); 206 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 207 } 208 if (is_zygote) { 209 // Reserve the address range before we create the non moving space to make sure bitmaps don't 210 // take it. 211 std::string error_str; 212 MemMap* mem_map = MemMap::MapAnonymous( 213 "main space", requested_alloc_space_begin + kNonMovingSpaceCapacity, capacity, 214 PROT_READ | PROT_WRITE, true, &error_str); 215 CHECK(mem_map != nullptr) << error_str; 216 // Non moving space is always dlmalloc since we currently don't have support for multiple 217 // rosalloc spaces. 218 non_moving_space_ = space::DlMallocSpace::Create( 219 "zygote / non moving space", initial_size, kNonMovingSpaceCapacity, kNonMovingSpaceCapacity, 220 requested_alloc_space_begin, false); 221 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 222 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 223 } else { 224 std::string error_str; 225 MemMap* mem_map = MemMap::MapAnonymous("main/non-moving space", requested_alloc_space_begin, 226 capacity, PROT_READ | PROT_WRITE, true, &error_str); 227 CHECK(mem_map != nullptr) << error_str; 228 // Create the main free list space, which doubles as the non moving space. We can do this since 229 // non zygote means that we won't have any background compaction. 230 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 231 non_moving_space_ = main_space_; 232 } 233 CHECK(non_moving_space_ != nullptr); 234 235 // We need to create the bump pointer if the foreground collector is a compacting GC. We only 236 // create the bump pointer space if we are not a moving foreground collector but have a moving 237 // background collector since the heap transition code will create the temp space by recycling 238 // the bitmap from the main space. 239 if (kMovingCollector && 240 (IsMovingGc(foreground_collector_type_) || IsMovingGc(background_collector_type_))) { 241 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 242 // Divide by 2 for a temporary fix for reducing virtual memory usage. 243 const size_t bump_pointer_space_capacity = capacity / 2; 244 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 245 bump_pointer_space_capacity, nullptr); 246 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 247 AddSpace(bump_pointer_space_); 248 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 249 bump_pointer_space_capacity, nullptr); 250 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 251 AddSpace(temp_space_); 252 } 253 if (non_moving_space_ != main_space_) { 254 AddSpace(non_moving_space_); 255 } 256 if (main_space_ != nullptr) { 257 AddSpace(main_space_); 258 } 259 260 // Allocate the large object space. 261 if (kUseFreeListSpaceForLOS) { 262 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 263 } else { 264 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 265 } 266 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 267 AddSpace(large_object_space_); 268 269 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 270 CHECK(!continuous_spaces_.empty()); 271 272 // Relies on the spaces being sorted. 273 byte* heap_begin = continuous_spaces_.front()->Begin(); 274 byte* heap_end = continuous_spaces_.back()->Limit(); 275 size_t heap_capacity = heap_end - heap_begin; 276 277 // Allocate the card table. 278 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 279 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 280 281 // Card cache for now since it makes it easier for us to update the references to the copying 282 // spaces. 283 accounting::ModUnionTable* mod_union_table = 284 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 285 GetImageSpace()); 286 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 287 AddModUnionTable(mod_union_table); 288 289 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 290 accounting::RememberedSet* non_moving_space_rem_set = 291 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 292 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 293 AddRememberedSet(non_moving_space_rem_set); 294 } 295 296 // TODO: Count objects in the image space here. 297 num_bytes_allocated_.StoreRelaxed(0); 298 299 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 300 kDefaultMarkStackSize)); 301 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 302 allocation_stack_.reset(accounting::ObjectStack::Create( 303 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 304 live_stack_.reset(accounting::ObjectStack::Create( 305 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 306 307 // It's still too early to take a lock because there are no threads yet, but we can create locks 308 // now. We don't create it earlier to make it clear that you can't use locks during heap 309 // initialization. 310 gc_complete_lock_ = new Mutex("GC complete lock"); 311 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 312 *gc_complete_lock_)); 313 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 314 last_gc_size_ = GetBytesAllocated(); 315 316 if (ignore_max_footprint_) { 317 SetIdealFootprint(std::numeric_limits<size_t>::max()); 318 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 319 } 320 CHECK_NE(max_allowed_footprint_, 0U); 321 322 // Create our garbage collectors. 323 for (size_t i = 0; i < 2; ++i) { 324 const bool concurrent = i != 0; 325 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 326 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 327 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 328 } 329 if (kMovingCollector) { 330 // TODO: Clean this up. 331 bool generational = foreground_collector_type_ == kCollectorTypeGSS; 332 semi_space_collector_ = new collector::SemiSpace(this, generational, 333 generational ? "generational" : ""); 334 garbage_collectors_.push_back(semi_space_collector_); 335 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 336 garbage_collectors_.push_back(concurrent_copying_collector_); 337 mark_compact_collector_ = new collector::MarkCompact(this); 338 garbage_collectors_.push_back(mark_compact_collector_); 339 } 340 341 if (GetImageSpace() != nullptr && main_space_ != nullptr) { 342 // Check that there's no gap between the image space and the main 343 // space so that the immune region won't break (eg. due to a large 344 // object allocated in the gap). 345 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), main_space_->GetMemMap()); 346 if (!no_gap) { 347 MemMap::DumpMaps(LOG(ERROR)); 348 LOG(FATAL) << "There's a gap between the image space and the main space"; 349 } 350 } 351 352 if (running_on_valgrind_) { 353 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 354 } 355 356 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 357 LOG(INFO) << "Heap() exiting"; 358 } 359} 360 361void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 362 size_t capacity) { 363 // Is background compaction is enabled? 364 bool can_move_objects = IsMovingGc(background_collector_type_) != 365 IsMovingGc(foreground_collector_type_); 366 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 367 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 368 // from the main space to the zygote space. If background compaction is enabled, always pass in 369 // that we can move objets. 370 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 371 // After the zygote we want this to be false if we don't have background compaction enabled so 372 // that getting primitive array elements is faster. 373 can_move_objects = !have_zygote_space_; 374 } 375 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 376 RemoveRememberedSet(main_space_); 377 } 378 if (kUseRosAlloc) { 379 rosalloc_space_ = space::RosAllocSpace::CreateFromMemMap( 380 mem_map, "main rosalloc space", kDefaultStartingSize, initial_size, growth_limit, capacity, 381 low_memory_mode_, can_move_objects); 382 main_space_ = rosalloc_space_; 383 CHECK(main_space_ != nullptr) << "Failed to create rosalloc space"; 384 } else { 385 dlmalloc_space_ = space::DlMallocSpace::CreateFromMemMap( 386 mem_map, "main dlmalloc space", kDefaultStartingSize, initial_size, growth_limit, capacity, 387 can_move_objects); 388 main_space_ = dlmalloc_space_; 389 CHECK(main_space_ != nullptr) << "Failed to create dlmalloc space"; 390 } 391 main_space_->SetFootprintLimit(main_space_->Capacity()); 392 if (collector::SemiSpace::kUseRememberedSet) { 393 accounting::RememberedSet* main_space_rem_set = 394 new accounting::RememberedSet("Main space remembered set", this, main_space_); 395 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 396 AddRememberedSet(main_space_rem_set); 397 } 398 VLOG(heap) << "Created main space " << main_space_; 399} 400 401void Heap::ChangeAllocator(AllocatorType allocator) { 402 if (current_allocator_ != allocator) { 403 // These two allocators are only used internally and don't have any entrypoints. 404 CHECK_NE(allocator, kAllocatorTypeLOS); 405 CHECK_NE(allocator, kAllocatorTypeNonMoving); 406 current_allocator_ = allocator; 407 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 408 SetQuickAllocEntryPointsAllocator(current_allocator_); 409 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 410 } 411} 412 413void Heap::DisableCompaction() { 414 if (IsMovingGc(foreground_collector_type_)) { 415 foreground_collector_type_ = kCollectorTypeCMS; 416 } 417 if (IsMovingGc(background_collector_type_)) { 418 background_collector_type_ = foreground_collector_type_; 419 } 420 TransitionCollector(foreground_collector_type_); 421} 422 423std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 424 if (!IsValidContinuousSpaceObjectAddress(klass)) { 425 return StringPrintf("<non heap address klass %p>", klass); 426 } 427 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 428 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 429 std::string result("["); 430 result += SafeGetClassDescriptor(component_type); 431 return result; 432 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 433 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 434 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 435 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 436 } else { 437 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 438 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 439 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 440 } 441 const DexFile* dex_file = dex_cache->GetDexFile(); 442 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 443 if (class_def_idx == DexFile::kDexNoIndex16) { 444 return "<class def not found>"; 445 } 446 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 447 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 448 return dex_file->GetTypeDescriptor(type_id); 449 } 450} 451 452std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 453 if (obj == nullptr) { 454 return "null"; 455 } 456 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 457 if (klass == nullptr) { 458 return "(class=null)"; 459 } 460 std::string result(SafeGetClassDescriptor(klass)); 461 if (obj->IsClass()) { 462 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 463 } 464 return result; 465} 466 467void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 468 if (obj == nullptr) { 469 stream << "(obj=null)"; 470 return; 471 } 472 if (IsAligned<kObjectAlignment>(obj)) { 473 space::Space* space = nullptr; 474 // Don't use find space since it only finds spaces which actually contain objects instead of 475 // spaces which may contain objects (e.g. cleared bump pointer spaces). 476 for (const auto& cur_space : continuous_spaces_) { 477 if (cur_space->HasAddress(obj)) { 478 space = cur_space; 479 break; 480 } 481 } 482 // Unprotect all the spaces. 483 for (const auto& space : continuous_spaces_) { 484 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 485 } 486 stream << "Object " << obj; 487 if (space != nullptr) { 488 stream << " in space " << *space; 489 } 490 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 491 stream << "\nclass=" << klass; 492 if (klass != nullptr) { 493 stream << " type= " << SafePrettyTypeOf(obj); 494 } 495 // Re-protect the address we faulted on. 496 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 497 } 498} 499 500bool Heap::IsCompilingBoot() const { 501 for (const auto& space : continuous_spaces_) { 502 if (space->IsImageSpace() || space->IsZygoteSpace()) { 503 return false; 504 } 505 } 506 return true; 507} 508 509bool Heap::HasImageSpace() const { 510 for (const auto& space : continuous_spaces_) { 511 if (space->IsImageSpace()) { 512 return true; 513 } 514 } 515 return false; 516} 517 518void Heap::IncrementDisableMovingGC(Thread* self) { 519 // Need to do this holding the lock to prevent races where the GC is about to run / running when 520 // we attempt to disable it. 521 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 522 MutexLock mu(self, *gc_complete_lock_); 523 ++disable_moving_gc_count_; 524 if (IsMovingGc(collector_type_running_)) { 525 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 526 } 527} 528 529void Heap::DecrementDisableMovingGC(Thread* self) { 530 MutexLock mu(self, *gc_complete_lock_); 531 CHECK_GE(disable_moving_gc_count_, 0U); 532 --disable_moving_gc_count_; 533} 534 535void Heap::UpdateProcessState(ProcessState process_state) { 536 if (process_state_ != process_state) { 537 process_state_ = process_state; 538 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 539 // Start at index 1 to avoid "is always false" warning. 540 // Have iteration 1 always transition the collector. 541 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 542 ? foreground_collector_type_ : background_collector_type_); 543 usleep(kCollectorTransitionStressWait); 544 } 545 if (process_state_ == kProcessStateJankPerceptible) { 546 // Transition back to foreground right away to prevent jank. 547 RequestCollectorTransition(foreground_collector_type_, 0); 548 } else { 549 // Don't delay for debug builds since we may want to stress test the GC. 550 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 551 kCollectorTransitionWait); 552 } 553 } 554} 555 556void Heap::CreateThreadPool() { 557 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 558 if (num_threads != 0) { 559 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 560 } 561} 562 563void Heap::VisitObjects(ObjectCallback callback, void* arg) { 564 Thread* self = Thread::Current(); 565 // GCs can move objects, so don't allow this. 566 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 567 if (bump_pointer_space_ != nullptr) { 568 // Visit objects in bump pointer space. 569 bump_pointer_space_->Walk(callback, arg); 570 } 571 // TODO: Switch to standard begin and end to use ranged a based loop. 572 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 573 it < end; ++it) { 574 mirror::Object* obj = *it; 575 if (obj != nullptr && obj->GetClass() != nullptr) { 576 // Avoid the race condition caused by the object not yet being written into the allocation 577 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 578 // there can be nulls on the allocation stack. 579 callback(obj, arg); 580 } 581 } 582 GetLiveBitmap()->Walk(callback, arg); 583 self->EndAssertNoThreadSuspension(old_cause); 584} 585 586void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 587 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 588 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 589 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 590 // TODO: Generalize this to n bitmaps? 591 if (space1 == nullptr) { 592 DCHECK(space2 != nullptr); 593 space1 = space2; 594 } 595 if (space2 == nullptr) { 596 DCHECK(space1 != nullptr); 597 space2 = space1; 598 } 599 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 600 large_object_space_->GetLiveBitmap(), stack); 601} 602 603void Heap::DeleteThreadPool() { 604 thread_pool_.reset(nullptr); 605} 606 607void Heap::AddSpace(space::Space* space) { 608 DCHECK(space != nullptr); 609 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 610 if (space->IsContinuousSpace()) { 611 DCHECK(!space->IsDiscontinuousSpace()); 612 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 613 // Continuous spaces don't necessarily have bitmaps. 614 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 615 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 616 if (live_bitmap != nullptr) { 617 DCHECK(mark_bitmap != nullptr); 618 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 619 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 620 } 621 continuous_spaces_.push_back(continuous_space); 622 // Ensure that spaces remain sorted in increasing order of start address. 623 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 624 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 625 return a->Begin() < b->Begin(); 626 }); 627 } else { 628 DCHECK(space->IsDiscontinuousSpace()); 629 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 630 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 631 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 632 discontinuous_spaces_.push_back(discontinuous_space); 633 } 634 if (space->IsAllocSpace()) { 635 alloc_spaces_.push_back(space->AsAllocSpace()); 636 } 637} 638 639void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 640 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 641 if (continuous_space->IsDlMallocSpace()) { 642 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 643 } else if (continuous_space->IsRosAllocSpace()) { 644 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 645 } 646} 647 648void Heap::RemoveSpace(space::Space* space) { 649 DCHECK(space != nullptr); 650 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 651 if (space->IsContinuousSpace()) { 652 DCHECK(!space->IsDiscontinuousSpace()); 653 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 654 // Continuous spaces don't necessarily have bitmaps. 655 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 656 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 657 if (live_bitmap != nullptr) { 658 DCHECK(mark_bitmap != nullptr); 659 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 660 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 661 } 662 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 663 DCHECK(it != continuous_spaces_.end()); 664 continuous_spaces_.erase(it); 665 } else { 666 DCHECK(space->IsDiscontinuousSpace()); 667 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 668 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 669 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 670 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 671 discontinuous_space); 672 DCHECK(it != discontinuous_spaces_.end()); 673 discontinuous_spaces_.erase(it); 674 } 675 if (space->IsAllocSpace()) { 676 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 677 DCHECK(it != alloc_spaces_.end()); 678 alloc_spaces_.erase(it); 679 } 680} 681 682void Heap::RegisterGCAllocation(size_t bytes) { 683 if (this != nullptr) { 684 gc_memory_overhead_.FetchAndAddSequentiallyConsistent(bytes); 685 } 686} 687 688void Heap::RegisterGCDeAllocation(size_t bytes) { 689 if (this != nullptr) { 690 gc_memory_overhead_.FetchAndSubSequentiallyConsistent(bytes); 691 } 692} 693 694void Heap::DumpGcPerformanceInfo(std::ostream& os) { 695 // Dump cumulative timings. 696 os << "Dumping cumulative Gc timings\n"; 697 uint64_t total_duration = 0; 698 // Dump cumulative loggers for each GC type. 699 uint64_t total_paused_time = 0; 700 for (auto& collector : garbage_collectors_) { 701 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 702 const size_t iterations = logger.GetIterations(); 703 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 704 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 705 os << ConstDumpable<CumulativeLogger>(logger); 706 const uint64_t total_ns = logger.GetTotalNs(); 707 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 708 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 709 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 710 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 711 Histogram<uint64_t>::CumulativeData cumulative_data; 712 pause_histogram.CreateHistogram(&cumulative_data); 713 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 714 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 715 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 716 << collector->GetName() << " freed: " << freed_objects 717 << " objects with total size " << PrettySize(freed_bytes) << "\n" 718 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 719 << PrettySize(freed_bytes / seconds) << "/s\n"; 720 total_duration += total_ns; 721 total_paused_time += total_pause_ns; 722 } 723 collector->ResetMeasurements(); 724 } 725 uint64_t allocation_time = 726 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 727 if (total_duration != 0) { 728 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 729 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 730 os << "Mean GC size throughput: " 731 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 732 os << "Mean GC object throughput: " 733 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 734 } 735 size_t total_objects_allocated = GetObjectsAllocatedEver(); 736 os << "Total number of allocations: " << total_objects_allocated << "\n"; 737 size_t total_bytes_allocated = GetBytesAllocatedEver(); 738 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 739 if (kMeasureAllocationTime) { 740 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 741 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 742 << "\n"; 743 } 744 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 745 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 746 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_.LoadRelaxed(); 747 BaseMutex::DumpAll(os); 748} 749 750Heap::~Heap() { 751 VLOG(heap) << "Starting ~Heap()"; 752 STLDeleteElements(&garbage_collectors_); 753 // If we don't reset then the mark stack complains in its destructor. 754 allocation_stack_->Reset(); 755 live_stack_->Reset(); 756 STLDeleteValues(&mod_union_tables_); 757 STLDeleteValues(&remembered_sets_); 758 STLDeleteElements(&continuous_spaces_); 759 STLDeleteElements(&discontinuous_spaces_); 760 delete gc_complete_lock_; 761 delete heap_trim_request_lock_; 762 VLOG(heap) << "Finished ~Heap()"; 763} 764 765space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 766 bool fail_ok) const { 767 for (const auto& space : continuous_spaces_) { 768 if (space->Contains(obj)) { 769 return space; 770 } 771 } 772 if (!fail_ok) { 773 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 774 } 775 return NULL; 776} 777 778space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 779 bool fail_ok) const { 780 for (const auto& space : discontinuous_spaces_) { 781 if (space->Contains(obj)) { 782 return space; 783 } 784 } 785 if (!fail_ok) { 786 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 787 } 788 return NULL; 789} 790 791space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 792 space::Space* result = FindContinuousSpaceFromObject(obj, true); 793 if (result != NULL) { 794 return result; 795 } 796 return FindDiscontinuousSpaceFromObject(obj, true); 797} 798 799space::ImageSpace* Heap::GetImageSpace() const { 800 for (const auto& space : continuous_spaces_) { 801 if (space->IsImageSpace()) { 802 return space->AsImageSpace(); 803 } 804 } 805 return NULL; 806} 807 808static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 809 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 810 if (used_bytes < chunk_size) { 811 size_t chunk_free_bytes = chunk_size - used_bytes; 812 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 813 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 814 } 815} 816 817void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 818 std::ostringstream oss; 819 size_t total_bytes_free = GetFreeMemory(); 820 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 821 << " free bytes"; 822 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 823 if (!large_object_allocation && total_bytes_free >= byte_count) { 824 size_t max_contiguous_allocation = 0; 825 for (const auto& space : continuous_spaces_) { 826 if (space->IsMallocSpace()) { 827 // To allow the Walk/InspectAll() to exclusively-lock the mutator 828 // lock, temporarily release the shared access to the mutator 829 // lock here by transitioning to the suspended state. 830 Locks::mutator_lock_->AssertSharedHeld(self); 831 self->TransitionFromRunnableToSuspended(kSuspended); 832 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 833 self->TransitionFromSuspendedToRunnable(); 834 Locks::mutator_lock_->AssertSharedHeld(self); 835 } 836 } 837 oss << "; failed due to fragmentation (largest possible contiguous allocation " 838 << max_contiguous_allocation << " bytes)"; 839 } 840 self->ThrowOutOfMemoryError(oss.str().c_str()); 841} 842 843void Heap::DoPendingTransitionOrTrim() { 844 Thread* self = Thread::Current(); 845 CollectorType desired_collector_type; 846 // Wait until we reach the desired transition time. 847 while (true) { 848 uint64_t wait_time; 849 { 850 MutexLock mu(self, *heap_trim_request_lock_); 851 desired_collector_type = desired_collector_type_; 852 uint64_t current_time = NanoTime(); 853 if (current_time >= heap_transition_or_trim_target_time_) { 854 break; 855 } 856 wait_time = heap_transition_or_trim_target_time_ - current_time; 857 } 858 ScopedThreadStateChange tsc(self, kSleeping); 859 usleep(wait_time / 1000); // Usleep takes microseconds. 860 } 861 // Transition the collector if the desired collector type is not the same as the current 862 // collector type. 863 TransitionCollector(desired_collector_type); 864 if (!CareAboutPauseTimes()) { 865 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 866 // about pauses. 867 Runtime* runtime = Runtime::Current(); 868 runtime->GetThreadList()->SuspendAll(); 869 uint64_t start_time = NanoTime(); 870 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 871 VLOG(heap) << "Deflating " << count << " monitors took " 872 << PrettyDuration(NanoTime() - start_time); 873 runtime->GetThreadList()->ResumeAll(); 874 } 875 // Do a heap trim if it is needed. 876 Trim(); 877} 878 879void Heap::Trim() { 880 Thread* self = Thread::Current(); 881 { 882 MutexLock mu(self, *heap_trim_request_lock_); 883 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 884 return; 885 } 886 last_trim_time_ = NanoTime(); 887 heap_trim_request_pending_ = false; 888 } 889 { 890 // Need to do this before acquiring the locks since we don't want to get suspended while 891 // holding any locks. 892 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 893 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 894 // trimming. 895 MutexLock mu(self, *gc_complete_lock_); 896 // Ensure there is only one GC at a time. 897 WaitForGcToCompleteLocked(kGcCauseTrim, self); 898 collector_type_running_ = kCollectorTypeHeapTrim; 899 } 900 uint64_t start_ns = NanoTime(); 901 // Trim the managed spaces. 902 uint64_t total_alloc_space_allocated = 0; 903 uint64_t total_alloc_space_size = 0; 904 uint64_t managed_reclaimed = 0; 905 for (const auto& space : continuous_spaces_) { 906 if (space->IsMallocSpace()) { 907 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 908 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 909 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 910 // for a long period of time. 911 managed_reclaimed += malloc_space->Trim(); 912 } 913 total_alloc_space_size += malloc_space->Size(); 914 } 915 } 916 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 917 if (bump_pointer_space_ != nullptr) { 918 total_alloc_space_allocated -= bump_pointer_space_->Size(); 919 } 920 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 921 static_cast<float>(total_alloc_space_size); 922 uint64_t gc_heap_end_ns = NanoTime(); 923 // We never move things in the native heap, so we can finish the GC at this point. 924 FinishGC(self, collector::kGcTypeNone); 925 size_t native_reclaimed = 0; 926 // Only trim the native heap if we don't care about pauses. 927 if (!CareAboutPauseTimes()) { 928#if defined(USE_DLMALLOC) 929 // Trim the native heap. 930 dlmalloc_trim(0); 931 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 932#elif defined(USE_JEMALLOC) 933 // Jemalloc does it's own internal trimming. 934#else 935 UNIMPLEMENTED(WARNING) << "Add trimming support"; 936#endif 937 } 938 uint64_t end_ns = NanoTime(); 939 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 940 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 941 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 942 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 943 << "%."; 944} 945 946bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 947 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 948 // taking the lock. 949 if (obj == nullptr) { 950 return true; 951 } 952 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 953} 954 955bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 956 return FindContinuousSpaceFromObject(obj, true) != nullptr; 957} 958 959bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 960 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 961 return false; 962 } 963 for (const auto& space : continuous_spaces_) { 964 if (space->HasAddress(obj)) { 965 return true; 966 } 967 } 968 return false; 969} 970 971bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 972 bool search_live_stack, bool sorted) { 973 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 974 return false; 975 } 976 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 977 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 978 if (obj == klass) { 979 // This case happens for java.lang.Class. 980 return true; 981 } 982 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 983 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 984 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 985 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 986 return temp_space_->Contains(obj); 987 } 988 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 989 space::DiscontinuousSpace* d_space = nullptr; 990 if (c_space != nullptr) { 991 if (c_space->GetLiveBitmap()->Test(obj)) { 992 return true; 993 } 994 } else { 995 d_space = FindDiscontinuousSpaceFromObject(obj, true); 996 if (d_space != nullptr) { 997 if (d_space->GetLiveBitmap()->Test(obj)) { 998 return true; 999 } 1000 } 1001 } 1002 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1003 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1004 if (i > 0) { 1005 NanoSleep(MsToNs(10)); 1006 } 1007 if (search_allocation_stack) { 1008 if (sorted) { 1009 if (allocation_stack_->ContainsSorted(obj)) { 1010 return true; 1011 } 1012 } else if (allocation_stack_->Contains(obj)) { 1013 return true; 1014 } 1015 } 1016 1017 if (search_live_stack) { 1018 if (sorted) { 1019 if (live_stack_->ContainsSorted(obj)) { 1020 return true; 1021 } 1022 } else if (live_stack_->Contains(obj)) { 1023 return true; 1024 } 1025 } 1026 } 1027 // We need to check the bitmaps again since there is a race where we mark something as live and 1028 // then clear the stack containing it. 1029 if (c_space != nullptr) { 1030 if (c_space->GetLiveBitmap()->Test(obj)) { 1031 return true; 1032 } 1033 } else { 1034 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1035 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1036 return true; 1037 } 1038 } 1039 return false; 1040} 1041 1042void Heap::DumpSpaces(std::ostream& stream) { 1043 for (const auto& space : continuous_spaces_) { 1044 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1045 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1046 stream << space << " " << *space << "\n"; 1047 if (live_bitmap != nullptr) { 1048 stream << live_bitmap << " " << *live_bitmap << "\n"; 1049 } 1050 if (mark_bitmap != nullptr) { 1051 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1052 } 1053 } 1054 for (const auto& space : discontinuous_spaces_) { 1055 stream << space << " " << *space << "\n"; 1056 } 1057} 1058 1059void Heap::VerifyObjectBody(mirror::Object* obj) { 1060 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1061 return; 1062 } 1063 // Ignore early dawn of the universe verifications. 1064 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1065 return; 1066 } 1067 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1068 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1069 CHECK(c != nullptr) << "Null class in object " << obj; 1070 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1071 CHECK(VerifyClassClass(c)); 1072 1073 if (verify_object_mode_ > kVerifyObjectModeFast) { 1074 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1075 if (!IsLiveObjectLocked(obj)) { 1076 DumpSpaces(); 1077 LOG(FATAL) << "Object is dead: " << obj; 1078 } 1079 } 1080} 1081 1082void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1083 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1084} 1085 1086void Heap::VerifyHeap() { 1087 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1088 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1089} 1090 1091void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1092 // Use signed comparison since freed bytes can be negative when background compaction foreground 1093 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1094 // free list backed space typically increasing memory footprint due to padding and binning. 1095 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1096 // Note: This relies on 2s complement for handling negative freed_bytes. 1097 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1098 if (Runtime::Current()->HasStatsEnabled()) { 1099 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1100 thread_stats->freed_objects += freed_objects; 1101 thread_stats->freed_bytes += freed_bytes; 1102 // TODO: Do this concurrently. 1103 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1104 global_stats->freed_objects += freed_objects; 1105 global_stats->freed_bytes += freed_bytes; 1106 } 1107} 1108 1109mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1110 size_t alloc_size, size_t* bytes_allocated, 1111 size_t* usable_size, 1112 mirror::Class** klass) { 1113 bool was_default_allocator = allocator == GetCurrentAllocator(); 1114 DCHECK(klass != nullptr); 1115 StackHandleScope<1> hs(self); 1116 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1117 klass = nullptr; // Invalidate for safety. 1118 // The allocation failed. If the GC is running, block until it completes, and then retry the 1119 // allocation. 1120 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1121 if (last_gc != collector::kGcTypeNone) { 1122 // If we were the default allocator but the allocator changed while we were suspended, 1123 // abort the allocation. 1124 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1125 return nullptr; 1126 } 1127 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1128 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1129 usable_size); 1130 if (ptr != nullptr) { 1131 return ptr; 1132 } 1133 } 1134 1135 collector::GcType tried_type = next_gc_type_; 1136 const bool gc_ran = 1137 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1138 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1139 return nullptr; 1140 } 1141 if (gc_ran) { 1142 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1143 usable_size); 1144 if (ptr != nullptr) { 1145 return ptr; 1146 } 1147 } 1148 1149 // Loop through our different Gc types and try to Gc until we get enough free memory. 1150 for (collector::GcType gc_type : gc_plan_) { 1151 if (gc_type == tried_type) { 1152 continue; 1153 } 1154 // Attempt to run the collector, if we succeed, re-try the allocation. 1155 const bool gc_ran = 1156 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1157 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1158 return nullptr; 1159 } 1160 if (gc_ran) { 1161 // Did we free sufficient memory for the allocation to succeed? 1162 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1163 usable_size); 1164 if (ptr != nullptr) { 1165 return ptr; 1166 } 1167 } 1168 } 1169 // Allocations have failed after GCs; this is an exceptional state. 1170 // Try harder, growing the heap if necessary. 1171 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1172 usable_size); 1173 if (ptr != nullptr) { 1174 return ptr; 1175 } 1176 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1177 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1178 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1179 // OOME. 1180 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1181 << " allocation"; 1182 // TODO: Run finalization, but this may cause more allocations to occur. 1183 // We don't need a WaitForGcToComplete here either. 1184 DCHECK(!gc_plan_.empty()); 1185 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1186 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1187 return nullptr; 1188 } 1189 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1190 if (ptr == nullptr) { 1191 ThrowOutOfMemoryError(self, alloc_size, allocator == kAllocatorTypeLOS); 1192 } 1193 return ptr; 1194} 1195 1196void Heap::SetTargetHeapUtilization(float target) { 1197 DCHECK_GT(target, 0.0f); // asserted in Java code 1198 DCHECK_LT(target, 1.0f); 1199 target_utilization_ = target; 1200} 1201 1202size_t Heap::GetObjectsAllocated() const { 1203 size_t total = 0; 1204 for (space::AllocSpace* space : alloc_spaces_) { 1205 total += space->GetObjectsAllocated(); 1206 } 1207 return total; 1208} 1209 1210size_t Heap::GetObjectsAllocatedEver() const { 1211 return GetObjectsFreedEver() + GetObjectsAllocated(); 1212} 1213 1214size_t Heap::GetBytesAllocatedEver() const { 1215 return GetBytesFreedEver() + GetBytesAllocated(); 1216} 1217 1218class InstanceCounter { 1219 public: 1220 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1221 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1222 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1223 } 1224 static void Callback(mirror::Object* obj, void* arg) 1225 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1226 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1227 mirror::Class* instance_class = obj->GetClass(); 1228 CHECK(instance_class != nullptr); 1229 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1230 if (instance_counter->use_is_assignable_from_) { 1231 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1232 ++instance_counter->counts_[i]; 1233 } 1234 } else if (instance_class == instance_counter->classes_[i]) { 1235 ++instance_counter->counts_[i]; 1236 } 1237 } 1238 } 1239 1240 private: 1241 const std::vector<mirror::Class*>& classes_; 1242 bool use_is_assignable_from_; 1243 uint64_t* const counts_; 1244 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1245}; 1246 1247void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1248 uint64_t* counts) { 1249 // Can't do any GC in this function since this may move classes. 1250 Thread* self = Thread::Current(); 1251 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1252 InstanceCounter counter(classes, use_is_assignable_from, counts); 1253 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1254 VisitObjects(InstanceCounter::Callback, &counter); 1255 self->EndAssertNoThreadSuspension(old_cause); 1256} 1257 1258class InstanceCollector { 1259 public: 1260 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1261 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1262 : class_(c), max_count_(max_count), instances_(instances) { 1263 } 1264 static void Callback(mirror::Object* obj, void* arg) 1265 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1266 DCHECK(arg != nullptr); 1267 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1268 mirror::Class* instance_class = obj->GetClass(); 1269 if (instance_class == instance_collector->class_) { 1270 if (instance_collector->max_count_ == 0 || 1271 instance_collector->instances_.size() < instance_collector->max_count_) { 1272 instance_collector->instances_.push_back(obj); 1273 } 1274 } 1275 } 1276 1277 private: 1278 mirror::Class* class_; 1279 uint32_t max_count_; 1280 std::vector<mirror::Object*>& instances_; 1281 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1282}; 1283 1284void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1285 std::vector<mirror::Object*>& instances) { 1286 // Can't do any GC in this function since this may move classes. 1287 Thread* self = Thread::Current(); 1288 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1289 InstanceCollector collector(c, max_count, instances); 1290 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1291 VisitObjects(&InstanceCollector::Callback, &collector); 1292 self->EndAssertNoThreadSuspension(old_cause); 1293} 1294 1295class ReferringObjectsFinder { 1296 public: 1297 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1298 std::vector<mirror::Object*>& referring_objects) 1299 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1300 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1301 } 1302 1303 static void Callback(mirror::Object* obj, void* arg) 1304 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1305 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1306 } 1307 1308 // For bitmap Visit. 1309 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1310 // annotalysis on visitors. 1311 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1312 o->VisitReferences<true>(*this, VoidFunctor()); 1313 } 1314 1315 // For Object::VisitReferences. 1316 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1317 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1318 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1319 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1320 referring_objects_.push_back(obj); 1321 } 1322 } 1323 1324 private: 1325 mirror::Object* object_; 1326 uint32_t max_count_; 1327 std::vector<mirror::Object*>& referring_objects_; 1328 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1329}; 1330 1331void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1332 std::vector<mirror::Object*>& referring_objects) { 1333 // Can't do any GC in this function since this may move the object o. 1334 Thread* self = Thread::Current(); 1335 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1336 ReferringObjectsFinder finder(o, max_count, referring_objects); 1337 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1338 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1339 self->EndAssertNoThreadSuspension(old_cause); 1340} 1341 1342void Heap::CollectGarbage(bool clear_soft_references) { 1343 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1344 // last GC will not have necessarily been cleared. 1345 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1346} 1347 1348void Heap::TransitionCollector(CollectorType collector_type) { 1349 if (collector_type == collector_type_) { 1350 return; 1351 } 1352 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1353 << " -> " << static_cast<int>(collector_type); 1354 uint64_t start_time = NanoTime(); 1355 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1356 Runtime* const runtime = Runtime::Current(); 1357 ThreadList* const tl = runtime->GetThreadList(); 1358 Thread* const self = Thread::Current(); 1359 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1360 Locks::mutator_lock_->AssertNotHeld(self); 1361 const bool copying_transition = 1362 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1363 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1364 // compacting_gc_disable_count_, this should rarely occurs). 1365 for (;;) { 1366 { 1367 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1368 MutexLock mu(self, *gc_complete_lock_); 1369 // Ensure there is only one GC at a time. 1370 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1371 // If someone else beat us to it and changed the collector before we could, exit. 1372 // This is safe to do before the suspend all since we set the collector_type_running_ before 1373 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1374 // then it would get blocked on WaitForGcToCompleteLocked. 1375 if (collector_type == collector_type_) { 1376 return; 1377 } 1378 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1379 if (!copying_transition || disable_moving_gc_count_ == 0) { 1380 // TODO: Not hard code in semi-space collector? 1381 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1382 break; 1383 } 1384 } 1385 usleep(1000); 1386 } 1387 if (runtime->IsShuttingDown(self)) { 1388 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1389 // cause objects to get finalized. 1390 FinishGC(self, collector::kGcTypeNone); 1391 return; 1392 } 1393 tl->SuspendAll(); 1394 switch (collector_type) { 1395 case kCollectorTypeSS: 1396 // Fall-through. 1397 case kCollectorTypeGSS: { 1398 if (!IsMovingGc(collector_type_)) { 1399 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1400 // pointer space last transition it will be protected. 1401 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1402 Compact(bump_pointer_space_, main_space_); 1403 // Remove the main space so that we don't try to trim it, this doens't work for debug 1404 // builds since RosAlloc attempts to read the magic number from a protected page. 1405 RemoveSpace(main_space_); 1406 } 1407 break; 1408 } 1409 case kCollectorTypeMS: 1410 // Fall through. 1411 case kCollectorTypeCMS: { 1412 if (IsMovingGc(collector_type_)) { 1413 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1414 AddSpace(main_space_); 1415 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1416 Compact(main_space_, bump_pointer_space_); 1417 } 1418 break; 1419 } 1420 default: { 1421 LOG(FATAL) << "Attempted to transition to invalid collector type " 1422 << static_cast<size_t>(collector_type); 1423 break; 1424 } 1425 } 1426 ChangeCollector(collector_type); 1427 tl->ResumeAll(); 1428 // Can't call into java code with all threads suspended. 1429 reference_processor_.EnqueueClearedReferences(self); 1430 uint64_t duration = NanoTime() - start_time; 1431 GrowForUtilization(semi_space_collector_); 1432 FinishGC(self, collector::kGcTypeFull); 1433 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1434 int32_t delta_allocated = before_allocated - after_allocated; 1435 std::string saved_str; 1436 if (delta_allocated >= 0) { 1437 saved_str = " saved at least " + PrettySize(delta_allocated); 1438 } else { 1439 saved_str = " expanded " + PrettySize(-delta_allocated); 1440 } 1441 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1442 << PrettyDuration(duration) << saved_str; 1443} 1444 1445void Heap::ChangeCollector(CollectorType collector_type) { 1446 // TODO: Only do this with all mutators suspended to avoid races. 1447 if (collector_type != collector_type_) { 1448 if (collector_type == kCollectorTypeMC) { 1449 // Don't allow mark compact unless support is compiled in. 1450 CHECK(kMarkCompactSupport); 1451 } 1452 collector_type_ = collector_type; 1453 gc_plan_.clear(); 1454 switch (collector_type_) { 1455 case kCollectorTypeCC: // Fall-through. 1456 case kCollectorTypeMC: // Fall-through. 1457 case kCollectorTypeSS: // Fall-through. 1458 case kCollectorTypeGSS: { 1459 gc_plan_.push_back(collector::kGcTypeFull); 1460 if (use_tlab_) { 1461 ChangeAllocator(kAllocatorTypeTLAB); 1462 } else { 1463 ChangeAllocator(kAllocatorTypeBumpPointer); 1464 } 1465 break; 1466 } 1467 case kCollectorTypeMS: { 1468 gc_plan_.push_back(collector::kGcTypeSticky); 1469 gc_plan_.push_back(collector::kGcTypePartial); 1470 gc_plan_.push_back(collector::kGcTypeFull); 1471 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1472 break; 1473 } 1474 case kCollectorTypeCMS: { 1475 gc_plan_.push_back(collector::kGcTypeSticky); 1476 gc_plan_.push_back(collector::kGcTypePartial); 1477 gc_plan_.push_back(collector::kGcTypeFull); 1478 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1479 break; 1480 } 1481 default: { 1482 LOG(FATAL) << "Unimplemented"; 1483 } 1484 } 1485 if (IsGcConcurrent()) { 1486 concurrent_start_bytes_ = 1487 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1488 } else { 1489 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1490 } 1491 } 1492} 1493 1494// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1495class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1496 public: 1497 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1498 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1499 } 1500 1501 void BuildBins(space::ContinuousSpace* space) { 1502 bin_live_bitmap_ = space->GetLiveBitmap(); 1503 bin_mark_bitmap_ = space->GetMarkBitmap(); 1504 BinContext context; 1505 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1506 context.collector_ = this; 1507 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1508 // Note: This requires traversing the space in increasing order of object addresses. 1509 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1510 // Add the last bin which spans after the last object to the end of the space. 1511 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1512 } 1513 1514 private: 1515 struct BinContext { 1516 uintptr_t prev_; // The end of the previous object. 1517 ZygoteCompactingCollector* collector_; 1518 }; 1519 // Maps from bin sizes to locations. 1520 std::multimap<size_t, uintptr_t> bins_; 1521 // Live bitmap of the space which contains the bins. 1522 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1523 // Mark bitmap of the space which contains the bins. 1524 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1525 1526 static void Callback(mirror::Object* obj, void* arg) 1527 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1528 DCHECK(arg != nullptr); 1529 BinContext* context = reinterpret_cast<BinContext*>(arg); 1530 ZygoteCompactingCollector* collector = context->collector_; 1531 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1532 size_t bin_size = object_addr - context->prev_; 1533 // Add the bin consisting of the end of the previous object to the start of the current object. 1534 collector->AddBin(bin_size, context->prev_); 1535 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1536 } 1537 1538 void AddBin(size_t size, uintptr_t position) { 1539 if (size != 0) { 1540 bins_.insert(std::make_pair(size, position)); 1541 } 1542 } 1543 1544 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1545 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1546 // allocator. 1547 return false; 1548 } 1549 1550 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1551 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1552 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1553 mirror::Object* forward_address; 1554 // Find the smallest bin which we can move obj in. 1555 auto it = bins_.lower_bound(object_size); 1556 if (it == bins_.end()) { 1557 // No available space in the bins, place it in the target space instead (grows the zygote 1558 // space). 1559 size_t bytes_allocated; 1560 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1561 if (to_space_live_bitmap_ != nullptr) { 1562 to_space_live_bitmap_->Set(forward_address); 1563 } else { 1564 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1565 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1566 } 1567 } else { 1568 size_t size = it->first; 1569 uintptr_t pos = it->second; 1570 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1571 forward_address = reinterpret_cast<mirror::Object*>(pos); 1572 // Set the live and mark bits so that sweeping system weaks works properly. 1573 bin_live_bitmap_->Set(forward_address); 1574 bin_mark_bitmap_->Set(forward_address); 1575 DCHECK_GE(size, object_size); 1576 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1577 } 1578 // Copy the object over to its new location. 1579 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1580 if (kUseBakerOrBrooksReadBarrier) { 1581 obj->AssertReadBarrierPointer(); 1582 if (kUseBrooksReadBarrier) { 1583 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1584 forward_address->SetReadBarrierPointer(forward_address); 1585 } 1586 forward_address->AssertReadBarrierPointer(); 1587 } 1588 return forward_address; 1589 } 1590}; 1591 1592void Heap::UnBindBitmaps() { 1593 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1594 for (const auto& space : GetContinuousSpaces()) { 1595 if (space->IsContinuousMemMapAllocSpace()) { 1596 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1597 if (alloc_space->HasBoundBitmaps()) { 1598 alloc_space->UnBindBitmaps(); 1599 } 1600 } 1601 } 1602} 1603 1604void Heap::PreZygoteFork() { 1605 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1606 Thread* self = Thread::Current(); 1607 MutexLock mu(self, zygote_creation_lock_); 1608 // Try to see if we have any Zygote spaces. 1609 if (have_zygote_space_) { 1610 return; 1611 } 1612 VLOG(heap) << "Starting PreZygoteFork"; 1613 // Trim the pages at the end of the non moving space. 1614 non_moving_space_->Trim(); 1615 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1616 // there. 1617 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1618 // Change the collector to the post zygote one. 1619 if (kCompactZygote) { 1620 DCHECK(semi_space_collector_ != nullptr); 1621 // Temporarily disable rosalloc verification because the zygote 1622 // compaction will mess up the rosalloc internal metadata. 1623 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1624 ZygoteCompactingCollector zygote_collector(this); 1625 zygote_collector.BuildBins(non_moving_space_); 1626 // Create a new bump pointer space which we will compact into. 1627 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1628 non_moving_space_->Limit()); 1629 // Compact the bump pointer space to a new zygote bump pointer space. 1630 bool reset_main_space = false; 1631 if (IsMovingGc(collector_type_)) { 1632 zygote_collector.SetFromSpace(bump_pointer_space_); 1633 } else { 1634 CHECK(main_space_ != nullptr); 1635 // Copy from the main space. 1636 zygote_collector.SetFromSpace(main_space_); 1637 reset_main_space = true; 1638 } 1639 zygote_collector.SetToSpace(&target_space); 1640 zygote_collector.SetSwapSemiSpaces(false); 1641 zygote_collector.Run(kGcCauseCollectorTransition, false); 1642 if (reset_main_space) { 1643 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1644 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1645 MemMap* mem_map = main_space_->ReleaseMemMap(); 1646 RemoveSpace(main_space_); 1647 space::Space* old_main_space = main_space_; 1648 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1649 delete old_main_space; 1650 AddSpace(main_space_); 1651 } else { 1652 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1653 } 1654 if (temp_space_ != nullptr) { 1655 CHECK(temp_space_->IsEmpty()); 1656 } 1657 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1658 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1659 // Update the end and write out image. 1660 non_moving_space_->SetEnd(target_space.End()); 1661 non_moving_space_->SetLimit(target_space.Limit()); 1662 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1663 } 1664 ChangeCollector(foreground_collector_type_); 1665 // Save the old space so that we can remove it after we complete creating the zygote space. 1666 space::MallocSpace* old_alloc_space = non_moving_space_; 1667 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1668 // the remaining available space. 1669 // Remove the old space before creating the zygote space since creating the zygote space sets 1670 // the old alloc space's bitmaps to nullptr. 1671 RemoveSpace(old_alloc_space); 1672 if (collector::SemiSpace::kUseRememberedSet) { 1673 // Sanity bound check. 1674 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1675 // Remove the remembered set for the now zygote space (the old 1676 // non-moving space). Note now that we have compacted objects into 1677 // the zygote space, the data in the remembered set is no longer 1678 // needed. The zygote space will instead have a mod-union table 1679 // from this point on. 1680 RemoveRememberedSet(old_alloc_space); 1681 } 1682 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1683 low_memory_mode_, 1684 &non_moving_space_); 1685 delete old_alloc_space; 1686 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1687 AddSpace(zygote_space); 1688 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1689 AddSpace(non_moving_space_); 1690 have_zygote_space_ = true; 1691 // Enable large object space allocations. 1692 large_object_threshold_ = kDefaultLargeObjectThreshold; 1693 // Create the zygote space mod union table. 1694 accounting::ModUnionTable* mod_union_table = 1695 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1696 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1697 AddModUnionTable(mod_union_table); 1698 if (collector::SemiSpace::kUseRememberedSet) { 1699 // Add a new remembered set for the post-zygote non-moving space. 1700 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1701 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1702 non_moving_space_); 1703 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1704 << "Failed to create post-zygote non-moving space remembered set"; 1705 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1706 } 1707} 1708 1709void Heap::FlushAllocStack() { 1710 MarkAllocStackAsLive(allocation_stack_.get()); 1711 allocation_stack_->Reset(); 1712} 1713 1714void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 1715 accounting::ContinuousSpaceBitmap* bitmap2, 1716 accounting::LargeObjectBitmap* large_objects, 1717 accounting::ObjectStack* stack) { 1718 DCHECK(bitmap1 != nullptr); 1719 DCHECK(bitmap2 != nullptr); 1720 mirror::Object** limit = stack->End(); 1721 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1722 const mirror::Object* obj = *it; 1723 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1724 if (bitmap1->HasAddress(obj)) { 1725 bitmap1->Set(obj); 1726 } else if (bitmap2->HasAddress(obj)) { 1727 bitmap2->Set(obj); 1728 } else { 1729 large_objects->Set(obj); 1730 } 1731 } 1732 } 1733} 1734 1735void Heap::SwapSemiSpaces() { 1736 CHECK(bump_pointer_space_ != nullptr); 1737 CHECK(temp_space_ != nullptr); 1738 std::swap(bump_pointer_space_, temp_space_); 1739} 1740 1741void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1742 space::ContinuousMemMapAllocSpace* source_space) { 1743 CHECK(kMovingCollector); 1744 if (target_space != source_space) { 1745 // Don't swap spaces since this isn't a typical semi space collection. 1746 semi_space_collector_->SetSwapSemiSpaces(false); 1747 semi_space_collector_->SetFromSpace(source_space); 1748 semi_space_collector_->SetToSpace(target_space); 1749 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1750 } else { 1751 CHECK(target_space->IsBumpPointerSpace()) 1752 << "In-place compaction is only supported for bump pointer spaces"; 1753 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 1754 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 1755 } 1756} 1757 1758collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1759 bool clear_soft_references) { 1760 Thread* self = Thread::Current(); 1761 Runtime* runtime = Runtime::Current(); 1762 // If the heap can't run the GC, silently fail and return that no GC was run. 1763 switch (gc_type) { 1764 case collector::kGcTypePartial: { 1765 if (!have_zygote_space_) { 1766 return collector::kGcTypeNone; 1767 } 1768 break; 1769 } 1770 default: { 1771 // Other GC types don't have any special cases which makes them not runnable. The main case 1772 // here is full GC. 1773 } 1774 } 1775 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1776 Locks::mutator_lock_->AssertNotHeld(self); 1777 if (self->IsHandlingStackOverflow()) { 1778 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1779 } 1780 bool compacting_gc; 1781 { 1782 gc_complete_lock_->AssertNotHeld(self); 1783 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1784 MutexLock mu(self, *gc_complete_lock_); 1785 // Ensure there is only one GC at a time. 1786 WaitForGcToCompleteLocked(gc_cause, self); 1787 compacting_gc = IsMovingGc(collector_type_); 1788 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1789 if (compacting_gc && disable_moving_gc_count_ != 0) { 1790 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1791 return collector::kGcTypeNone; 1792 } 1793 collector_type_running_ = collector_type_; 1794 } 1795 1796 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1797 ++runtime->GetStats()->gc_for_alloc_count; 1798 ++self->GetStats()->gc_for_alloc_count; 1799 } 1800 uint64_t gc_start_time_ns = NanoTime(); 1801 uint64_t gc_start_size = GetBytesAllocated(); 1802 // Approximate allocation rate in bytes / second. 1803 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1804 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1805 if (LIKELY(ms_delta != 0)) { 1806 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1807 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1808 } 1809 1810 DCHECK_LT(gc_type, collector::kGcTypeMax); 1811 DCHECK_NE(gc_type, collector::kGcTypeNone); 1812 1813 collector::GarbageCollector* collector = nullptr; 1814 // TODO: Clean this up. 1815 if (compacting_gc) { 1816 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1817 current_allocator_ == kAllocatorTypeTLAB); 1818 switch (collector_type_) { 1819 case kCollectorTypeSS: 1820 // Fall-through. 1821 case kCollectorTypeGSS: 1822 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1823 semi_space_collector_->SetToSpace(temp_space_); 1824 semi_space_collector_->SetSwapSemiSpaces(true); 1825 collector = semi_space_collector_; 1826 break; 1827 case kCollectorTypeCC: 1828 collector = concurrent_copying_collector_; 1829 break; 1830 case kCollectorTypeMC: 1831 mark_compact_collector_->SetSpace(bump_pointer_space_); 1832 collector = mark_compact_collector_; 1833 break; 1834 default: 1835 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 1836 } 1837 if (collector != mark_compact_collector_) { 1838 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1839 CHECK(temp_space_->IsEmpty()); 1840 } 1841 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 1842 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1843 current_allocator_ == kAllocatorTypeDlMalloc) { 1844 collector = FindCollectorByGcType(gc_type); 1845 } else { 1846 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1847 } 1848 CHECK(collector != nullptr) 1849 << "Could not find garbage collector with collector_type=" 1850 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1851 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1852 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1853 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1854 RequestHeapTrim(); 1855 // Enqueue cleared references. 1856 reference_processor_.EnqueueClearedReferences(self); 1857 // Grow the heap so that we know when to perform the next GC. 1858 GrowForUtilization(collector); 1859 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 1860 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 1861 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 1862 // (mutator time blocked >= long_pause_log_threshold_). 1863 bool log_gc = gc_cause == kGcCauseExplicit; 1864 if (!log_gc && CareAboutPauseTimes()) { 1865 // GC for alloc pauses the allocating thread, so consider it as a pause. 1866 log_gc = duration > long_gc_log_threshold_ || 1867 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1868 for (uint64_t pause : pause_times) { 1869 log_gc = log_gc || pause >= long_pause_log_threshold_; 1870 } 1871 } 1872 if (log_gc) { 1873 const size_t percent_free = GetPercentFree(); 1874 const size_t current_heap_size = GetBytesAllocated(); 1875 const size_t total_memory = GetTotalMemory(); 1876 std::ostringstream pause_string; 1877 for (size_t i = 0; i < pause_times.size(); ++i) { 1878 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 1879 << ((i != pause_times.size() - 1) ? "," : ""); 1880 } 1881 LOG(INFO) << gc_cause << " " << collector->GetName() 1882 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 1883 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 1884 << current_gc_iteration_.GetFreedLargeObjects() << "(" 1885 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 1886 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1887 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1888 << " total " << PrettyDuration((duration / 1000) * 1000); 1889 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 1890 } 1891 FinishGC(self, gc_type); 1892 // Inform DDMS that a GC completed. 1893 Dbg::GcDidFinish(); 1894 return gc_type; 1895} 1896 1897void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1898 MutexLock mu(self, *gc_complete_lock_); 1899 collector_type_running_ = kCollectorTypeNone; 1900 if (gc_type != collector::kGcTypeNone) { 1901 last_gc_type_ = gc_type; 1902 } 1903 // Wake anyone who may have been waiting for the GC to complete. 1904 gc_complete_cond_->Broadcast(self); 1905} 1906 1907static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1908 RootType /*root_type*/) { 1909 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1910 if (*root == obj) { 1911 LOG(INFO) << "Object " << obj << " is a root"; 1912 } 1913} 1914 1915class ScanVisitor { 1916 public: 1917 void operator()(const mirror::Object* obj) const { 1918 LOG(ERROR) << "Would have rescanned object " << obj; 1919 } 1920}; 1921 1922// Verify a reference from an object. 1923class VerifyReferenceVisitor { 1924 public: 1925 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 1926 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1927 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 1928 1929 size_t GetFailureCount() const { 1930 return fail_count_->LoadSequentiallyConsistent(); 1931 } 1932 1933 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1934 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1935 if (verify_referent_) { 1936 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 1937 } 1938 } 1939 1940 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1941 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1942 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 1943 } 1944 1945 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1946 return heap_->IsLiveObjectLocked(obj, true, false, true); 1947 } 1948 1949 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 1950 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1951 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1952 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 1953 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 1954 << " thread_id= " << thread_id << " root_type= " << root_type; 1955 } 1956 } 1957 1958 private: 1959 // TODO: Fix the no thread safety analysis. 1960 // Returns false on failure. 1961 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1962 NO_THREAD_SAFETY_ANALYSIS { 1963 if (ref == nullptr || IsLive(ref)) { 1964 // Verify that the reference is live. 1965 return true; 1966 } 1967 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 1968 // Print message on only on first failure to prevent spam. 1969 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1970 } 1971 if (obj != nullptr) { 1972 // Only do this part for non roots. 1973 accounting::CardTable* card_table = heap_->GetCardTable(); 1974 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1975 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1976 byte* card_addr = card_table->CardFromAddr(obj); 1977 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1978 << offset << "\n card value = " << static_cast<int>(*card_addr); 1979 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1980 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1981 } else { 1982 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1983 } 1984 1985 // Attmept to find the class inside of the recently freed objects. 1986 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1987 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1988 space::MallocSpace* space = ref_space->AsMallocSpace(); 1989 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1990 if (ref_class != nullptr) { 1991 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1992 << PrettyClass(ref_class); 1993 } else { 1994 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1995 } 1996 } 1997 1998 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1999 ref->GetClass()->IsClass()) { 2000 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2001 } else { 2002 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2003 << ") is not a valid heap address"; 2004 } 2005 2006 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2007 void* cover_begin = card_table->AddrFromCard(card_addr); 2008 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2009 accounting::CardTable::kCardSize); 2010 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2011 << "-" << cover_end; 2012 accounting::ContinuousSpaceBitmap* bitmap = 2013 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2014 2015 if (bitmap == nullptr) { 2016 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2017 if (!VerifyClassClass(obj->GetClass())) { 2018 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2019 } 2020 } else { 2021 // Print out how the object is live. 2022 if (bitmap->Test(obj)) { 2023 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2024 } 2025 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2026 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2027 } 2028 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2029 LOG(ERROR) << "Object " << obj << " found in live stack"; 2030 } 2031 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2032 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2033 } 2034 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2035 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2036 } 2037 // Attempt to see if the card table missed the reference. 2038 ScanVisitor scan_visitor; 2039 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2040 card_table->Scan(bitmap, byte_cover_begin, 2041 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2042 } 2043 2044 // Search to see if any of the roots reference our object. 2045 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2046 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2047 2048 // Search to see if any of the roots reference our reference. 2049 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2050 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2051 } 2052 return false; 2053 } 2054 2055 Heap* const heap_; 2056 Atomic<size_t>* const fail_count_; 2057 const bool verify_referent_; 2058}; 2059 2060// Verify all references within an object, for use with HeapBitmap::Visit. 2061class VerifyObjectVisitor { 2062 public: 2063 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2064 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2065 } 2066 2067 void operator()(mirror::Object* obj) const 2068 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2069 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2070 // be live or else how did we find it in the live bitmap? 2071 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2072 // The class doesn't count as a reference but we should verify it anyways. 2073 obj->VisitReferences<true>(visitor, visitor); 2074 } 2075 2076 static void VisitCallback(mirror::Object* obj, void* arg) 2077 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2078 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2079 visitor->operator()(obj); 2080 } 2081 2082 size_t GetFailureCount() const { 2083 return fail_count_->LoadSequentiallyConsistent(); 2084 } 2085 2086 private: 2087 Heap* const heap_; 2088 Atomic<size_t>* const fail_count_; 2089 const bool verify_referent_; 2090}; 2091 2092void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2093 // Slow path, the allocation stack push back must have already failed. 2094 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2095 do { 2096 // TODO: Add handle VerifyObject. 2097 StackHandleScope<1> hs(self); 2098 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2099 // Push our object into the reserve region of the allocaiton stack. This is only required due 2100 // to heap verification requiring that roots are live (either in the live bitmap or in the 2101 // allocation stack). 2102 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2103 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2104 } while (!allocation_stack_->AtomicPushBack(*obj)); 2105} 2106 2107void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2108 // Slow path, the allocation stack push back must have already failed. 2109 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2110 mirror::Object** start_address; 2111 mirror::Object** end_address; 2112 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2113 &end_address)) { 2114 // TODO: Add handle VerifyObject. 2115 StackHandleScope<1> hs(self); 2116 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2117 // Push our object into the reserve region of the allocaiton stack. This is only required due 2118 // to heap verification requiring that roots are live (either in the live bitmap or in the 2119 // allocation stack). 2120 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2121 // Push into the reserve allocation stack. 2122 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2123 } 2124 self->SetThreadLocalAllocationStack(start_address, end_address); 2125 // Retry on the new thread-local allocation stack. 2126 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2127} 2128 2129// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2130size_t Heap::VerifyHeapReferences(bool verify_referents) { 2131 Thread* self = Thread::Current(); 2132 Locks::mutator_lock_->AssertExclusiveHeld(self); 2133 // Lets sort our allocation stacks so that we can efficiently binary search them. 2134 allocation_stack_->Sort(); 2135 live_stack_->Sort(); 2136 // Since we sorted the allocation stack content, need to revoke all 2137 // thread-local allocation stacks. 2138 RevokeAllThreadLocalAllocationStacks(self); 2139 Atomic<size_t> fail_count_(0); 2140 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2141 // Verify objects in the allocation stack since these will be objects which were: 2142 // 1. Allocated prior to the GC (pre GC verification). 2143 // 2. Allocated during the GC (pre sweep GC verification). 2144 // We don't want to verify the objects in the live stack since they themselves may be 2145 // pointing to dead objects if they are not reachable. 2146 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2147 // Verify the roots: 2148 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2149 if (visitor.GetFailureCount() > 0) { 2150 // Dump mod-union tables. 2151 for (const auto& table_pair : mod_union_tables_) { 2152 accounting::ModUnionTable* mod_union_table = table_pair.second; 2153 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2154 } 2155 // Dump remembered sets. 2156 for (const auto& table_pair : remembered_sets_) { 2157 accounting::RememberedSet* remembered_set = table_pair.second; 2158 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2159 } 2160 DumpSpaces(); 2161 } 2162 return visitor.GetFailureCount(); 2163} 2164 2165class VerifyReferenceCardVisitor { 2166 public: 2167 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2168 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2169 Locks::heap_bitmap_lock_) 2170 : heap_(heap), failed_(failed) { 2171 } 2172 2173 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2174 // annotalysis on visitors. 2175 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2176 NO_THREAD_SAFETY_ANALYSIS { 2177 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2178 // Filter out class references since changing an object's class does not mark the card as dirty. 2179 // Also handles large objects, since the only reference they hold is a class reference. 2180 if (ref != nullptr && !ref->IsClass()) { 2181 accounting::CardTable* card_table = heap_->GetCardTable(); 2182 // If the object is not dirty and it is referencing something in the live stack other than 2183 // class, then it must be on a dirty card. 2184 if (!card_table->AddrIsInCardTable(obj)) { 2185 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2186 *failed_ = true; 2187 } else if (!card_table->IsDirty(obj)) { 2188 // TODO: Check mod-union tables. 2189 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2190 // kCardDirty - 1 if it didnt get touched since we aged it. 2191 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2192 if (live_stack->ContainsSorted(ref)) { 2193 if (live_stack->ContainsSorted(obj)) { 2194 LOG(ERROR) << "Object " << obj << " found in live stack"; 2195 } 2196 if (heap_->GetLiveBitmap()->Test(obj)) { 2197 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2198 } 2199 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2200 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2201 2202 // Print which field of the object is dead. 2203 if (!obj->IsObjectArray()) { 2204 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2205 CHECK(klass != NULL); 2206 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2207 : klass->GetIFields(); 2208 CHECK(fields != NULL); 2209 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2210 mirror::ArtField* cur = fields->Get(i); 2211 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2212 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2213 << PrettyField(cur); 2214 break; 2215 } 2216 } 2217 } else { 2218 mirror::ObjectArray<mirror::Object>* object_array = 2219 obj->AsObjectArray<mirror::Object>(); 2220 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2221 if (object_array->Get(i) == ref) { 2222 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2223 } 2224 } 2225 } 2226 2227 *failed_ = true; 2228 } 2229 } 2230 } 2231 } 2232 2233 private: 2234 Heap* const heap_; 2235 bool* const failed_; 2236}; 2237 2238class VerifyLiveStackReferences { 2239 public: 2240 explicit VerifyLiveStackReferences(Heap* heap) 2241 : heap_(heap), 2242 failed_(false) {} 2243 2244 void operator()(mirror::Object* obj) const 2245 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2246 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2247 obj->VisitReferences<true>(visitor, VoidFunctor()); 2248 } 2249 2250 bool Failed() const { 2251 return failed_; 2252 } 2253 2254 private: 2255 Heap* const heap_; 2256 bool failed_; 2257}; 2258 2259bool Heap::VerifyMissingCardMarks() { 2260 Thread* self = Thread::Current(); 2261 Locks::mutator_lock_->AssertExclusiveHeld(self); 2262 2263 // We need to sort the live stack since we binary search it. 2264 live_stack_->Sort(); 2265 // Since we sorted the allocation stack content, need to revoke all 2266 // thread-local allocation stacks. 2267 RevokeAllThreadLocalAllocationStacks(self); 2268 VerifyLiveStackReferences visitor(this); 2269 GetLiveBitmap()->Visit(visitor); 2270 2271 // We can verify objects in the live stack since none of these should reference dead objects. 2272 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2273 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2274 visitor(*it); 2275 } 2276 } 2277 2278 if (visitor.Failed()) { 2279 DumpSpaces(); 2280 return false; 2281 } 2282 return true; 2283} 2284 2285void Heap::SwapStacks(Thread* self) { 2286 if (kUseThreadLocalAllocationStack) { 2287 live_stack_->AssertAllZero(); 2288 } 2289 allocation_stack_.swap(live_stack_); 2290} 2291 2292void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2293 // This must be called only during the pause. 2294 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2295 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2296 MutexLock mu2(self, *Locks::thread_list_lock_); 2297 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2298 for (Thread* t : thread_list) { 2299 t->RevokeThreadLocalAllocationStack(); 2300 } 2301} 2302 2303void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2304 if (kIsDebugBuild) { 2305 if (bump_pointer_space_ != nullptr) { 2306 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2307 } 2308 } 2309} 2310 2311accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2312 auto it = mod_union_tables_.find(space); 2313 if (it == mod_union_tables_.end()) { 2314 return nullptr; 2315 } 2316 return it->second; 2317} 2318 2319accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2320 auto it = remembered_sets_.find(space); 2321 if (it == remembered_sets_.end()) { 2322 return nullptr; 2323 } 2324 return it->second; 2325} 2326 2327void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2328 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2329 // Clear cards and keep track of cards cleared in the mod-union table. 2330 for (const auto& space : continuous_spaces_) { 2331 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2332 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2333 if (table != nullptr) { 2334 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2335 "ImageModUnionClearCards"; 2336 TimingLogger::ScopedTiming t(name, timings); 2337 table->ClearCards(); 2338 } else if (use_rem_sets && rem_set != nullptr) { 2339 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2340 << static_cast<int>(collector_type_); 2341 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2342 rem_set->ClearCards(); 2343 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2344 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2345 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2346 // were dirty before the GC started. 2347 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2348 // -> clean(cleaning thread). 2349 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2350 // roots and then we scan / update mod union tables after. We will always scan either card. 2351 // If we end up with the non aged card, we scan it it in the pause. 2352 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2353 VoidFunctor()); 2354 } 2355 } 2356} 2357 2358static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2359} 2360 2361void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2362 Thread* const self = Thread::Current(); 2363 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2364 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2365 if (verify_pre_gc_heap_) { 2366 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2367 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2368 size_t failures = VerifyHeapReferences(); 2369 if (failures > 0) { 2370 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2371 << " failures"; 2372 } 2373 } 2374 // Check that all objects which reference things in the live stack are on dirty cards. 2375 if (verify_missing_card_marks_) { 2376 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2377 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2378 SwapStacks(self); 2379 // Sort the live stack so that we can quickly binary search it later. 2380 if (!VerifyMissingCardMarks()) { 2381 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2382 } 2383 SwapStacks(self); 2384 } 2385 if (verify_mod_union_table_) { 2386 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2387 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2388 for (const auto& table_pair : mod_union_tables_) { 2389 accounting::ModUnionTable* mod_union_table = table_pair.second; 2390 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2391 mod_union_table->Verify(); 2392 } 2393 } 2394} 2395 2396void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2397 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2398 collector::GarbageCollector::ScopedPause pause(gc); 2399 PreGcVerificationPaused(gc); 2400 } 2401} 2402 2403void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2404 // TODO: Add a new runtime option for this? 2405 if (verify_pre_gc_rosalloc_) { 2406 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2407 } 2408} 2409 2410void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2411 Thread* const self = Thread::Current(); 2412 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2413 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2414 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2415 // reachable objects. 2416 if (verify_pre_sweeping_heap_) { 2417 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2418 CHECK_NE(self->GetState(), kRunnable); 2419 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2420 // Swapping bound bitmaps does nothing. 2421 gc->SwapBitmaps(); 2422 // Pass in false since concurrent reference processing can mean that the reference referents 2423 // may point to dead objects at the point which PreSweepingGcVerification is called. 2424 size_t failures = VerifyHeapReferences(false); 2425 if (failures > 0) { 2426 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2427 << " failures"; 2428 } 2429 gc->SwapBitmaps(); 2430 } 2431 if (verify_pre_sweeping_rosalloc_) { 2432 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2433 } 2434} 2435 2436void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2437 // Only pause if we have to do some verification. 2438 Thread* const self = Thread::Current(); 2439 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2440 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2441 if (verify_system_weaks_) { 2442 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2443 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2444 mark_sweep->VerifySystemWeaks(); 2445 } 2446 if (verify_post_gc_rosalloc_) { 2447 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2448 } 2449 if (verify_post_gc_heap_) { 2450 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2451 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2452 size_t failures = VerifyHeapReferences(); 2453 if (failures > 0) { 2454 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2455 << " failures"; 2456 } 2457 } 2458} 2459 2460void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2461 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2462 collector::GarbageCollector::ScopedPause pause(gc); 2463 PreGcVerificationPaused(gc); 2464 } 2465} 2466 2467void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2468 TimingLogger::ScopedTiming t(name, timings); 2469 for (const auto& space : continuous_spaces_) { 2470 if (space->IsRosAllocSpace()) { 2471 VLOG(heap) << name << " : " << space->GetName(); 2472 space->AsRosAllocSpace()->Verify(); 2473 } 2474 } 2475} 2476 2477collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2478 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2479 MutexLock mu(self, *gc_complete_lock_); 2480 return WaitForGcToCompleteLocked(cause, self); 2481} 2482 2483collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2484 collector::GcType last_gc_type = collector::kGcTypeNone; 2485 uint64_t wait_start = NanoTime(); 2486 while (collector_type_running_ != kCollectorTypeNone) { 2487 ATRACE_BEGIN("GC: Wait For Completion"); 2488 // We must wait, change thread state then sleep on gc_complete_cond_; 2489 gc_complete_cond_->Wait(self); 2490 last_gc_type = last_gc_type_; 2491 ATRACE_END(); 2492 } 2493 uint64_t wait_time = NanoTime() - wait_start; 2494 total_wait_time_ += wait_time; 2495 if (wait_time > long_pause_log_threshold_) { 2496 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2497 << " for cause " << cause; 2498 } 2499 return last_gc_type; 2500} 2501 2502void Heap::DumpForSigQuit(std::ostream& os) { 2503 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2504 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2505 DumpGcPerformanceInfo(os); 2506} 2507 2508size_t Heap::GetPercentFree() { 2509 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2510} 2511 2512void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2513 if (max_allowed_footprint > GetMaxMemory()) { 2514 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2515 << PrettySize(GetMaxMemory()); 2516 max_allowed_footprint = GetMaxMemory(); 2517 } 2518 max_allowed_footprint_ = max_allowed_footprint; 2519} 2520 2521bool Heap::IsMovableObject(const mirror::Object* obj) const { 2522 if (kMovingCollector) { 2523 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2524 if (space != nullptr) { 2525 // TODO: Check large object? 2526 return space->CanMoveObjects(); 2527 } 2528 } 2529 return false; 2530} 2531 2532void Heap::UpdateMaxNativeFootprint() { 2533 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2534 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2535 size_t target_size = native_size / GetTargetHeapUtilization(); 2536 if (target_size > native_size + max_free_) { 2537 target_size = native_size + max_free_; 2538 } else if (target_size < native_size + min_free_) { 2539 target_size = native_size + min_free_; 2540 } 2541 native_footprint_gc_watermark_ = target_size; 2542 native_footprint_limit_ = 2 * target_size - native_size; 2543} 2544 2545collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2546 for (const auto& collector : garbage_collectors_) { 2547 if (collector->GetCollectorType() == collector_type_ && 2548 collector->GetGcType() == gc_type) { 2549 return collector; 2550 } 2551 } 2552 return nullptr; 2553} 2554 2555double Heap::HeapGrowthMultiplier() const { 2556 // If we don't care about pause times we are background, so return 1.0. 2557 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2558 return 1.0; 2559 } 2560 return foreground_heap_growth_multiplier_; 2561} 2562 2563void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2564 // We know what our utilization is at this moment. 2565 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2566 const uint64_t bytes_allocated = GetBytesAllocated(); 2567 last_gc_size_ = bytes_allocated; 2568 last_gc_time_ns_ = NanoTime(); 2569 uint64_t target_size; 2570 collector::GcType gc_type = collector_ran->GetGcType(); 2571 if (gc_type != collector::kGcTypeSticky) { 2572 // Grow the heap for non sticky GC. 2573 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2574 // foreground. 2575 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2576 CHECK_GE(delta, 0); 2577 target_size = bytes_allocated + delta * multiplier; 2578 target_size = std::min(target_size, 2579 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2580 target_size = std::max(target_size, 2581 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2582 native_need_to_run_finalization_ = true; 2583 next_gc_type_ = collector::kGcTypeSticky; 2584 } else { 2585 collector::GcType non_sticky_gc_type = 2586 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2587 // Find what the next non sticky collector will be. 2588 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2589 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2590 // do another sticky collection next. 2591 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2592 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2593 // if the sticky GC throughput always remained >= the full/partial throughput. 2594 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2595 non_sticky_collector->GetEstimatedMeanThroughput() && 2596 non_sticky_collector->NumberOfIterations() > 0 && 2597 bytes_allocated <= max_allowed_footprint_) { 2598 next_gc_type_ = collector::kGcTypeSticky; 2599 } else { 2600 next_gc_type_ = non_sticky_gc_type; 2601 } 2602 // If we have freed enough memory, shrink the heap back down. 2603 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2604 target_size = bytes_allocated + max_free_; 2605 } else { 2606 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2607 } 2608 } 2609 if (!ignore_max_footprint_) { 2610 SetIdealFootprint(target_size); 2611 if (IsGcConcurrent()) { 2612 // Calculate when to perform the next ConcurrentGC. 2613 // Calculate the estimated GC duration. 2614 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2615 // Estimate how many remaining bytes we will have when we need to start the next GC. 2616 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2617 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2618 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2619 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2620 // A never going to happen situation that from the estimated allocation rate we will exceed 2621 // the applications entire footprint with the given estimated allocation rate. Schedule 2622 // another GC nearly straight away. 2623 remaining_bytes = kMinConcurrentRemainingBytes; 2624 } 2625 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2626 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2627 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2628 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2629 // right away. 2630 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2631 static_cast<size_t>(bytes_allocated)); 2632 } 2633 } 2634} 2635 2636void Heap::ClearGrowthLimit() { 2637 growth_limit_ = capacity_; 2638 non_moving_space_->ClearGrowthLimit(); 2639} 2640 2641void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2642 ScopedObjectAccess soa(self); 2643 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2644 jvalue args[1]; 2645 args[0].l = arg.get(); 2646 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2647 // Restore object in case it gets moved. 2648 *object = soa.Decode<mirror::Object*>(arg.get()); 2649} 2650 2651void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2652 StackHandleScope<1> hs(self); 2653 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2654 RequestConcurrentGC(self); 2655} 2656 2657void Heap::RequestConcurrentGC(Thread* self) { 2658 // Make sure that we can do a concurrent GC. 2659 Runtime* runtime = Runtime::Current(); 2660 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2661 self->IsHandlingStackOverflow()) { 2662 return; 2663 } 2664 // We already have a request pending, no reason to start more until we update 2665 // concurrent_start_bytes_. 2666 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2667 JNIEnv* env = self->GetJniEnv(); 2668 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2669 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2670 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2671 WellKnownClasses::java_lang_Daemons_requestGC); 2672 CHECK(!env->ExceptionCheck()); 2673} 2674 2675void Heap::ConcurrentGC(Thread* self) { 2676 if (Runtime::Current()->IsShuttingDown(self)) { 2677 return; 2678 } 2679 // Wait for any GCs currently running to finish. 2680 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2681 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2682 // instead. E.g. can't do partial, so do full instead. 2683 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2684 collector::kGcTypeNone) { 2685 for (collector::GcType gc_type : gc_plan_) { 2686 // Attempt to run the collector, if we succeed, we are done. 2687 if (gc_type > next_gc_type_ && 2688 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2689 break; 2690 } 2691 } 2692 } 2693 } 2694} 2695 2696void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2697 Thread* self = Thread::Current(); 2698 { 2699 MutexLock mu(self, *heap_trim_request_lock_); 2700 if (desired_collector_type_ == desired_collector_type) { 2701 return; 2702 } 2703 heap_transition_or_trim_target_time_ = 2704 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 2705 desired_collector_type_ = desired_collector_type; 2706 } 2707 SignalHeapTrimDaemon(self); 2708} 2709 2710void Heap::RequestHeapTrim() { 2711 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2712 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2713 // a space it will hold its lock and can become a cause of jank. 2714 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2715 // forking. 2716 2717 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2718 // because that only marks object heads, so a large array looks like lots of empty space. We 2719 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2720 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2721 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2722 // not how much use we're making of those pages. 2723 2724 Thread* self = Thread::Current(); 2725 Runtime* runtime = Runtime::Current(); 2726 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2727 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2728 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2729 // as we don't hold the lock while requesting the trim). 2730 return; 2731 } 2732 { 2733 MutexLock mu(self, *heap_trim_request_lock_); 2734 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2735 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2736 // just yet. 2737 return; 2738 } 2739 heap_trim_request_pending_ = true; 2740 uint64_t current_time = NanoTime(); 2741 if (heap_transition_or_trim_target_time_ < current_time) { 2742 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 2743 } 2744 } 2745 // Notify the daemon thread which will actually do the heap trim. 2746 SignalHeapTrimDaemon(self); 2747} 2748 2749void Heap::SignalHeapTrimDaemon(Thread* self) { 2750 JNIEnv* env = self->GetJniEnv(); 2751 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2752 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2753 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2754 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2755 CHECK(!env->ExceptionCheck()); 2756} 2757 2758void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2759 if (rosalloc_space_ != nullptr) { 2760 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2761 } 2762 if (bump_pointer_space_ != nullptr) { 2763 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2764 } 2765} 2766 2767void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2768 if (rosalloc_space_ != nullptr) { 2769 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2770 } 2771} 2772 2773void Heap::RevokeAllThreadLocalBuffers() { 2774 if (rosalloc_space_ != nullptr) { 2775 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2776 } 2777 if (bump_pointer_space_ != nullptr) { 2778 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2779 } 2780} 2781 2782bool Heap::IsGCRequestPending() const { 2783 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2784} 2785 2786void Heap::RunFinalization(JNIEnv* env) { 2787 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2788 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2789 CHECK(WellKnownClasses::java_lang_System != nullptr); 2790 WellKnownClasses::java_lang_System_runFinalization = 2791 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2792 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2793 } 2794 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2795 WellKnownClasses::java_lang_System_runFinalization); 2796} 2797 2798void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2799 Thread* self = ThreadForEnv(env); 2800 if (native_need_to_run_finalization_) { 2801 RunFinalization(env); 2802 UpdateMaxNativeFootprint(); 2803 native_need_to_run_finalization_ = false; 2804 } 2805 // Total number of native bytes allocated. 2806 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 2807 new_native_bytes_allocated += bytes; 2808 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 2809 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2810 collector::kGcTypeFull; 2811 2812 // The second watermark is higher than the gc watermark. If you hit this it means you are 2813 // allocating native objects faster than the GC can keep up with. 2814 if (new_native_bytes_allocated > native_footprint_limit_) { 2815 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 2816 // Just finished a GC, attempt to run finalizers. 2817 RunFinalization(env); 2818 CHECK(!env->ExceptionCheck()); 2819 } 2820 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2821 if (new_native_bytes_allocated > native_footprint_limit_) { 2822 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2823 RunFinalization(env); 2824 native_need_to_run_finalization_ = false; 2825 CHECK(!env->ExceptionCheck()); 2826 } 2827 // We have just run finalizers, update the native watermark since it is very likely that 2828 // finalizers released native managed allocations. 2829 UpdateMaxNativeFootprint(); 2830 } else if (!IsGCRequestPending()) { 2831 if (IsGcConcurrent()) { 2832 RequestConcurrentGC(self); 2833 } else { 2834 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2835 } 2836 } 2837 } 2838} 2839 2840void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2841 int expected_size, new_size; 2842 do { 2843 expected_size = native_bytes_allocated_.LoadRelaxed(); 2844 new_size = expected_size - bytes; 2845 if (UNLIKELY(new_size < 0)) { 2846 ScopedObjectAccess soa(env); 2847 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2848 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2849 "registered as allocated", bytes, expected_size).c_str()); 2850 break; 2851 } 2852 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, new_size)); 2853} 2854 2855size_t Heap::GetTotalMemory() const { 2856 size_t ret = 0; 2857 for (const auto& space : continuous_spaces_) { 2858 // Currently don't include the image space. 2859 if (!space->IsImageSpace()) { 2860 ret += space->Size(); 2861 } 2862 } 2863 for (const auto& space : discontinuous_spaces_) { 2864 if (space->IsLargeObjectSpace()) { 2865 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2866 } 2867 } 2868 return ret; 2869} 2870 2871void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2872 DCHECK(mod_union_table != nullptr); 2873 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2874} 2875 2876void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2877 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2878 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2879 c->GetDescriptor().empty()); 2880 CHECK_GE(byte_count, sizeof(mirror::Object)); 2881} 2882 2883void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2884 CHECK(remembered_set != nullptr); 2885 space::Space* space = remembered_set->GetSpace(); 2886 CHECK(space != nullptr); 2887 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 2888 remembered_sets_.Put(space, remembered_set); 2889 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 2890} 2891 2892void Heap::RemoveRememberedSet(space::Space* space) { 2893 CHECK(space != nullptr); 2894 auto it = remembered_sets_.find(space); 2895 CHECK(it != remembered_sets_.end()); 2896 remembered_sets_.erase(it); 2897 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2898} 2899 2900void Heap::ClearMarkedObjects() { 2901 // Clear all of the spaces' mark bitmaps. 2902 for (const auto& space : GetContinuousSpaces()) { 2903 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2904 if (space->GetLiveBitmap() != mark_bitmap) { 2905 mark_bitmap->Clear(); 2906 } 2907 } 2908 // Clear the marked objects in the discontinous space object sets. 2909 for (const auto& space : GetDiscontinuousSpaces()) { 2910 space->GetMarkBitmap()->Clear(); 2911 } 2912} 2913 2914} // namespace gc 2915} // namespace art 2916