heap.cc revision 7840888bd9b6accdb32c38563e78a9dc201f1303
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <vector> 24 25#include "base/histogram-inl.h" 26#include "base/stl_util.h" 27#include "common_throws.h" 28#include "cutils/sched_policy.h" 29#include "debugger.h" 30#include "gc/accounting/atomic_stack.h" 31#include "gc/accounting/card_table-inl.h" 32#include "gc/accounting/heap_bitmap-inl.h" 33#include "gc/accounting/mod_union_table.h" 34#include "gc/accounting/mod_union_table-inl.h" 35#include "gc/accounting/remembered_set.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/concurrent_copying.h" 38#include "gc/collector/mark_sweep-inl.h" 39#include "gc/collector/partial_mark_sweep.h" 40#include "gc/collector/semi_space.h" 41#include "gc/collector/sticky_mark_sweep.h" 42#include "gc/space/bump_pointer_space.h" 43#include "gc/space/dlmalloc_space-inl.h" 44#include "gc/space/image_space.h" 45#include "gc/space/large_object_space.h" 46#include "gc/space/rosalloc_space-inl.h" 47#include "gc/space/space-inl.h" 48#include "gc/space/zygote_space.h" 49#include "entrypoints/quick/quick_alloc_entrypoints.h" 50#include "heap-inl.h" 51#include "image.h" 52#include "mirror/art_field-inl.h" 53#include "mirror/class-inl.h" 54#include "mirror/object.h" 55#include "mirror/object-inl.h" 56#include "mirror/object_array-inl.h" 57#include "mirror/reference-inl.h" 58#include "object_utils.h" 59#include "os.h" 60#include "reflection.h" 61#include "runtime.h" 62#include "ScopedLocalRef.h" 63#include "scoped_thread_state_change.h" 64#include "sirt_ref.h" 65#include "thread_list.h" 66#include "UniquePtr.h" 67#include "well_known_classes.h" 68 69namespace art { 70 71namespace gc { 72 73static constexpr size_t kCollectorTransitionStressIterations = 0; 74static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 75static constexpr bool kGCALotMode = false; 76static constexpr size_t kGcAlotInterval = KB; 77// Minimum amount of remaining bytes before a concurrent GC is triggered. 78static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 79static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 80// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 81// relative to partial/full GC. This is desirable since sticky GCs interfere less with mutator 82// threads (lower pauses, use less memory bandwidth). 83static constexpr double kStickyGcThroughputAdjustment = 1.25; 84// Whether or not we use the free list large object space. 85static constexpr bool kUseFreeListSpaceForLOS = false; 86// Whtehr or not we compact the zygote in PreZygoteFork. 87static constexpr bool kCompactZygote = kMovingCollector; 88static constexpr size_t kNonMovingSpaceCapacity = 64 * MB; 89 90Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 91 double target_utilization, size_t capacity, const std::string& image_file_name, 92 CollectorType foreground_collector_type, CollectorType background_collector_type, 93 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 94 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 95 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 96 bool verify_post_gc_heap, bool verify_pre_gc_rosalloc, 97 bool verify_post_gc_rosalloc) 98 : non_moving_space_(nullptr), 99 rosalloc_space_(nullptr), 100 dlmalloc_space_(nullptr), 101 main_space_(nullptr), 102 collector_type_(kCollectorTypeNone), 103 foreground_collector_type_(foreground_collector_type), 104 background_collector_type_(background_collector_type), 105 desired_collector_type_(foreground_collector_type_), 106 heap_trim_request_lock_(nullptr), 107 last_trim_time_(0), 108 heap_transition_target_time_(0), 109 heap_trim_request_pending_(false), 110 parallel_gc_threads_(parallel_gc_threads), 111 conc_gc_threads_(conc_gc_threads), 112 low_memory_mode_(low_memory_mode), 113 long_pause_log_threshold_(long_pause_log_threshold), 114 long_gc_log_threshold_(long_gc_log_threshold), 115 ignore_max_footprint_(ignore_max_footprint), 116 have_zygote_space_(false), 117 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 118 collector_type_running_(kCollectorTypeNone), 119 last_gc_type_(collector::kGcTypeNone), 120 next_gc_type_(collector::kGcTypePartial), 121 capacity_(capacity), 122 growth_limit_(growth_limit), 123 max_allowed_footprint_(initial_size), 124 native_footprint_gc_watermark_(initial_size), 125 native_footprint_limit_(2 * initial_size), 126 native_need_to_run_finalization_(false), 127 // Initially assume we perceive jank in case the process state is never updated. 128 process_state_(kProcessStateJankPerceptible), 129 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 130 total_bytes_freed_ever_(0), 131 total_objects_freed_ever_(0), 132 num_bytes_allocated_(0), 133 native_bytes_allocated_(0), 134 gc_memory_overhead_(0), 135 verify_missing_card_marks_(false), 136 verify_system_weaks_(false), 137 verify_pre_gc_heap_(verify_pre_gc_heap), 138 verify_post_gc_heap_(verify_post_gc_heap), 139 verify_mod_union_table_(false), 140 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 141 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 142 allocation_rate_(0), 143 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 144 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 145 * verification is enabled, we limit the size of allocation stacks to speed up their 146 * searching. 147 */ 148 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 149 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 150 current_allocator_(kAllocatorTypeDlMalloc), 151 current_non_moving_allocator_(kAllocatorTypeNonMoving), 152 bump_pointer_space_(nullptr), 153 temp_space_(nullptr), 154 min_free_(min_free), 155 max_free_(max_free), 156 target_utilization_(target_utilization), 157 total_wait_time_(0), 158 total_allocation_time_(0), 159 verify_object_mode_(kVerifyObjectModeDisabled), 160 disable_moving_gc_count_(0), 161 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 162 use_tlab_(use_tlab) { 163 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 164 LOG(INFO) << "Heap() entering"; 165 } 166 const bool is_zygote = Runtime::Current()->IsZygote(); 167 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 168 // entrypoints. 169 if (!is_zygote) { 170 large_object_threshold_ = kDefaultLargeObjectThreshold; 171 // Background compaction is currently not supported for command line runs. 172 if (background_collector_type_ != foreground_collector_type_) { 173 LOG(WARNING) << "Disabling background compaction for non zygote"; 174 background_collector_type_ = foreground_collector_type_; 175 } 176 } 177 ChangeCollector(desired_collector_type_); 178 179 live_bitmap_.reset(new accounting::HeapBitmap(this)); 180 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 181 // Requested begin for the alloc space, to follow the mapped image and oat files 182 byte* requested_alloc_space_begin = nullptr; 183 if (!image_file_name.empty()) { 184 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 185 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 186 AddSpace(image_space); 187 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 188 // isn't going to get in the middle 189 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 190 CHECK_GT(oat_file_end_addr, image_space->End()); 191 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 192 } 193 if (is_zygote) { 194 // Reserve the address range before we create the non moving space to make sure bitmaps don't 195 // take it. 196 std::string error_str; 197 MemMap* mem_map = MemMap::MapAnonymous( 198 "main space", requested_alloc_space_begin + kNonMovingSpaceCapacity, capacity, 199 PROT_READ | PROT_WRITE, true, &error_str); 200 CHECK(mem_map != nullptr) << error_str; 201 // Non moving space is always dlmalloc since we currently don't have support for multiple 202 // rosalloc spaces. 203 non_moving_space_ = space::DlMallocSpace::Create( 204 "zygote / non moving space", initial_size, kNonMovingSpaceCapacity, kNonMovingSpaceCapacity, 205 requested_alloc_space_begin, false); 206 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 207 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 208 } else { 209 std::string error_str; 210 MemMap* mem_map = MemMap::MapAnonymous("main/non-moving space", requested_alloc_space_begin, 211 capacity, PROT_READ | PROT_WRITE, true, &error_str); 212 CHECK(mem_map != nullptr) << error_str; 213 // Create the main free list space, which doubles as the non moving space. We can do this since 214 // non zygote means that we won't have any background compaction. 215 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 216 non_moving_space_ = main_space_; 217 } 218 CHECK(non_moving_space_ != nullptr); 219 220 // We need to create the bump pointer if the foreground collector is a compacting GC. We only 221 // create the bump pointer space if we are not a moving foreground collector but have a moving 222 // background collector since the heap transition code will create the temp space by recycling 223 // the bitmap from the main space. 224 if (kMovingCollector) { 225 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 226 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", capacity, nullptr); 227 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 228 AddSpace(bump_pointer_space_); 229 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", capacity, nullptr); 230 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 231 AddSpace(temp_space_); 232 } 233 if (non_moving_space_ != main_space_) { 234 AddSpace(non_moving_space_); 235 } 236 if (main_space_ != nullptr) { 237 AddSpace(main_space_); 238 } 239 240 // Allocate the large object space. 241 if (kUseFreeListSpaceForLOS) { 242 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 243 } else { 244 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 245 } 246 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 247 AddSpace(large_object_space_); 248 249 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 250 CHECK(!continuous_spaces_.empty()); 251 252 // Relies on the spaces being sorted. 253 byte* heap_begin = continuous_spaces_.front()->Begin(); 254 byte* heap_end = continuous_spaces_.back()->Limit(); 255 size_t heap_capacity = heap_end - heap_begin; 256 257 // Allocate the card table. 258 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 259 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 260 261 // Card cache for now since it makes it easier for us to update the references to the copying 262 // spaces. 263 accounting::ModUnionTable* mod_union_table = 264 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 265 GetImageSpace()); 266 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 267 AddModUnionTable(mod_union_table); 268 269 if (collector::SemiSpace::kUseRememberedSet) { 270 accounting::RememberedSet* non_moving_space_rem_set = 271 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 272 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 273 AddRememberedSet(non_moving_space_rem_set); 274 if (main_space_ != nullptr && main_space_ != non_moving_space_) { 275 accounting::RememberedSet* main_space_rem_set = 276 new accounting::RememberedSet("Main space remembered set", this, main_space_); 277 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 278 AddRememberedSet(main_space_rem_set); 279 } 280 } 281 282 // TODO: Count objects in the image space here. 283 num_bytes_allocated_ = 0; 284 285 // Default mark stack size in bytes. 286 static const size_t default_mark_stack_size = 64 * KB; 287 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 288 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 289 max_allocation_stack_size_)); 290 live_stack_.reset(accounting::ObjectStack::Create("live stack", 291 max_allocation_stack_size_)); 292 293 // It's still too early to take a lock because there are no threads yet, but we can create locks 294 // now. We don't create it earlier to make it clear that you can't use locks during heap 295 // initialization. 296 gc_complete_lock_ = new Mutex("GC complete lock"); 297 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 298 *gc_complete_lock_)); 299 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 300 last_gc_size_ = GetBytesAllocated(); 301 302 if (ignore_max_footprint_) { 303 SetIdealFootprint(std::numeric_limits<size_t>::max()); 304 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 305 } 306 CHECK_NE(max_allowed_footprint_, 0U); 307 308 // Create our garbage collectors. 309 for (size_t i = 0; i < 2; ++i) { 310 const bool concurrent = i != 0; 311 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 312 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 313 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 314 } 315 if (kMovingCollector) { 316 // TODO: Clean this up. 317 bool generational = foreground_collector_type_ == kCollectorTypeGSS; 318 semi_space_collector_ = new collector::SemiSpace(this, generational, 319 generational ? "generational" : ""); 320 garbage_collectors_.push_back(semi_space_collector_); 321 322 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 323 garbage_collectors_.push_back(concurrent_copying_collector_); 324 } 325 326 if (running_on_valgrind_) { 327 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 328 } 329 330 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 331 LOG(INFO) << "Heap() exiting"; 332 } 333} 334 335void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 336 size_t capacity) { 337 // Is background compaction is enabled? 338 bool can_move_objects = IsMovingGc(background_collector_type_) != 339 IsMovingGc(foreground_collector_type_); 340 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 341 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 342 // from the main space to the zygote space. If background compaction is enabled, always pass in 343 // that we can move objets. 344 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 345 // After the zygote we want this to be false if we don't have background compaction enabled so 346 // that getting primitive array elements is faster. 347 can_move_objects = !have_zygote_space_; 348 } 349 if (kUseRosAlloc) { 350 main_space_ = space::RosAllocSpace::CreateFromMemMap(mem_map, "main rosalloc space", 351 kDefaultStartingSize, initial_size, 352 growth_limit, capacity, low_memory_mode_, 353 can_move_objects); 354 CHECK(main_space_ != nullptr) << "Failed to create rosalloc space"; 355 } else { 356 main_space_ = space::DlMallocSpace::CreateFromMemMap(mem_map, "main dlmalloc space", 357 kDefaultStartingSize, initial_size, 358 growth_limit, capacity, 359 can_move_objects); 360 CHECK(main_space_ != nullptr) << "Failed to create dlmalloc space"; 361 } 362 main_space_->SetFootprintLimit(main_space_->Capacity()); 363 VLOG(heap) << "Created main space " << main_space_; 364} 365 366void Heap::ChangeAllocator(AllocatorType allocator) { 367 if (current_allocator_ != allocator) { 368 // These two allocators are only used internally and don't have any entrypoints. 369 CHECK_NE(allocator, kAllocatorTypeLOS); 370 CHECK_NE(allocator, kAllocatorTypeNonMoving); 371 current_allocator_ = allocator; 372 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 373 SetQuickAllocEntryPointsAllocator(current_allocator_); 374 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 375 } 376} 377 378void Heap::DisableCompaction() { 379 if (IsMovingGc(foreground_collector_type_)) { 380 foreground_collector_type_ = kCollectorTypeCMS; 381 } 382 if (IsMovingGc(background_collector_type_)) { 383 background_collector_type_ = foreground_collector_type_; 384 } 385 TransitionCollector(foreground_collector_type_); 386} 387 388std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 389 if (!IsValidContinuousSpaceObjectAddress(klass)) { 390 return StringPrintf("<non heap address klass %p>", klass); 391 } 392 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 393 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 394 std::string result("["); 395 result += SafeGetClassDescriptor(component_type); 396 return result; 397 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 398 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 399 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 400 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 401 } else { 402 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 403 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 404 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 405 } 406 const DexFile* dex_file = dex_cache->GetDexFile(); 407 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 408 if (class_def_idx == DexFile::kDexNoIndex16) { 409 return "<class def not found>"; 410 } 411 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 412 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 413 return dex_file->GetTypeDescriptor(type_id); 414 } 415} 416 417std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 418 if (obj == nullptr) { 419 return "null"; 420 } 421 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 422 if (klass == nullptr) { 423 return "(class=null)"; 424 } 425 std::string result(SafeGetClassDescriptor(klass)); 426 if (obj->IsClass()) { 427 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 428 } 429 return result; 430} 431 432void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 433 if (obj == nullptr) { 434 stream << "(obj=null)"; 435 return; 436 } 437 if (IsAligned<kObjectAlignment>(obj)) { 438 space::Space* space = nullptr; 439 // Don't use find space since it only finds spaces which actually contain objects instead of 440 // spaces which may contain objects (e.g. cleared bump pointer spaces). 441 for (const auto& cur_space : continuous_spaces_) { 442 if (cur_space->HasAddress(obj)) { 443 space = cur_space; 444 break; 445 } 446 } 447 // Unprotect all the spaces. 448 for (const auto& space : continuous_spaces_) { 449 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 450 } 451 stream << "Object " << obj; 452 if (space != nullptr) { 453 stream << " in space " << *space; 454 } 455 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 456 stream << "\nclass=" << klass; 457 if (klass != nullptr) { 458 stream << " type= " << SafePrettyTypeOf(obj); 459 } 460 // Re-protect the address we faulted on. 461 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 462 } 463} 464 465bool Heap::IsCompilingBoot() const { 466 for (const auto& space : continuous_spaces_) { 467 if (space->IsImageSpace() || space->IsZygoteSpace()) { 468 return false; 469 } 470 } 471 return true; 472} 473 474bool Heap::HasImageSpace() const { 475 for (const auto& space : continuous_spaces_) { 476 if (space->IsImageSpace()) { 477 return true; 478 } 479 } 480 return false; 481} 482 483void Heap::IncrementDisableMovingGC(Thread* self) { 484 // Need to do this holding the lock to prevent races where the GC is about to run / running when 485 // we attempt to disable it. 486 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 487 MutexLock mu(self, *gc_complete_lock_); 488 ++disable_moving_gc_count_; 489 if (IsMovingGc(collector_type_running_)) { 490 WaitForGcToCompleteLocked(self); 491 } 492} 493 494void Heap::DecrementDisableMovingGC(Thread* self) { 495 MutexLock mu(self, *gc_complete_lock_); 496 CHECK_GE(disable_moving_gc_count_, 0U); 497 --disable_moving_gc_count_; 498} 499 500void Heap::UpdateProcessState(ProcessState process_state) { 501 if (process_state_ != process_state) { 502 process_state_ = process_state; 503 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 504 // Start at index 1 to avoid "is always false" warning. 505 // Have iteration 1 always transition the collector. 506 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 507 ? foreground_collector_type_ : background_collector_type_); 508 usleep(kCollectorTransitionStressWait); 509 } 510 if (process_state_ == kProcessStateJankPerceptible) { 511 // Transition back to foreground right away to prevent jank. 512 RequestCollectorTransition(foreground_collector_type_, 0); 513 } else { 514 // Don't delay for debug builds since we may want to stress test the GC. 515 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 516 kCollectorTransitionWait); 517 } 518 } 519} 520 521void Heap::CreateThreadPool() { 522 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 523 if (num_threads != 0) { 524 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 525 } 526} 527 528void Heap::VisitObjects(ObjectCallback callback, void* arg) { 529 Thread* self = Thread::Current(); 530 // GCs can move objects, so don't allow this. 531 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 532 if (bump_pointer_space_ != nullptr) { 533 // Visit objects in bump pointer space. 534 bump_pointer_space_->Walk(callback, arg); 535 } 536 // TODO: Switch to standard begin and end to use ranged a based loop. 537 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 538 it < end; ++it) { 539 mirror::Object* obj = *it; 540 if (obj != nullptr && obj->GetClass() != nullptr) { 541 // Avoid the race condition caused by the object not yet being written into the allocation 542 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 543 // there can be nulls on the allocation stack. 544 callback(obj, arg); 545 } 546 } 547 GetLiveBitmap()->Walk(callback, arg); 548 self->EndAssertNoThreadSuspension(old_cause); 549} 550 551void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 552 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 553 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 554 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 555 // TODO: Generalize this to n bitmaps? 556 if (space1 == nullptr) { 557 DCHECK(space2 != nullptr); 558 space1 = space2; 559 } 560 if (space2 == nullptr) { 561 DCHECK(space1 != nullptr); 562 space2 = space1; 563 } 564 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 565 large_object_space_->GetLiveObjects(), stack); 566} 567 568void Heap::DeleteThreadPool() { 569 thread_pool_.reset(nullptr); 570} 571 572void Heap::AddSpace(space::Space* space, bool set_as_default) { 573 DCHECK(space != nullptr); 574 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 575 if (space->IsContinuousSpace()) { 576 DCHECK(!space->IsDiscontinuousSpace()); 577 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 578 // Continuous spaces don't necessarily have bitmaps. 579 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 580 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 581 if (live_bitmap != nullptr) { 582 DCHECK(mark_bitmap != nullptr); 583 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 584 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 585 } 586 continuous_spaces_.push_back(continuous_space); 587 if (set_as_default) { 588 if (continuous_space->IsDlMallocSpace()) { 589 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 590 } else if (continuous_space->IsRosAllocSpace()) { 591 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 592 } 593 } 594 // Ensure that spaces remain sorted in increasing order of start address. 595 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 596 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 597 return a->Begin() < b->Begin(); 598 }); 599 } else { 600 DCHECK(space->IsDiscontinuousSpace()); 601 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 602 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 603 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 604 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 605 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 606 discontinuous_spaces_.push_back(discontinuous_space); 607 } 608 if (space->IsAllocSpace()) { 609 alloc_spaces_.push_back(space->AsAllocSpace()); 610 } 611} 612 613void Heap::RemoveSpace(space::Space* space) { 614 DCHECK(space != nullptr); 615 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 616 if (space->IsContinuousSpace()) { 617 DCHECK(!space->IsDiscontinuousSpace()); 618 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 619 // Continuous spaces don't necessarily have bitmaps. 620 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 621 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 622 if (live_bitmap != nullptr) { 623 DCHECK(mark_bitmap != nullptr); 624 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 625 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 626 } 627 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 628 DCHECK(it != continuous_spaces_.end()); 629 continuous_spaces_.erase(it); 630 if (continuous_space == dlmalloc_space_) { 631 dlmalloc_space_ = nullptr; 632 } else if (continuous_space == rosalloc_space_) { 633 rosalloc_space_ = nullptr; 634 } 635 if (continuous_space == main_space_) { 636 main_space_ = nullptr; 637 } else if (continuous_space == bump_pointer_space_) { 638 bump_pointer_space_ = nullptr; 639 } else if (continuous_space == temp_space_) { 640 temp_space_ = nullptr; 641 } 642 } else { 643 DCHECK(space->IsDiscontinuousSpace()); 644 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 645 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 646 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 647 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 648 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 649 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 650 discontinuous_space); 651 DCHECK(it != discontinuous_spaces_.end()); 652 discontinuous_spaces_.erase(it); 653 } 654 if (space->IsAllocSpace()) { 655 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 656 DCHECK(it != alloc_spaces_.end()); 657 alloc_spaces_.erase(it); 658 } 659} 660 661void Heap::RegisterGCAllocation(size_t bytes) { 662 if (this != nullptr) { 663 gc_memory_overhead_.FetchAndAdd(bytes); 664 } 665} 666 667void Heap::RegisterGCDeAllocation(size_t bytes) { 668 if (this != nullptr) { 669 gc_memory_overhead_.FetchAndSub(bytes); 670 } 671} 672 673void Heap::DumpGcPerformanceInfo(std::ostream& os) { 674 // Dump cumulative timings. 675 os << "Dumping cumulative Gc timings\n"; 676 uint64_t total_duration = 0; 677 // Dump cumulative loggers for each GC type. 678 uint64_t total_paused_time = 0; 679 for (auto& collector : garbage_collectors_) { 680 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 681 const size_t iterations = logger.GetIterations(); 682 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 683 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 684 os << ConstDumpable<CumulativeLogger>(logger); 685 const uint64_t total_ns = logger.GetTotalNs(); 686 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 687 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 688 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 689 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 690 Histogram<uint64_t>::CumulativeData cumulative_data; 691 pause_histogram.CreateHistogram(&cumulative_data); 692 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 693 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 694 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 695 << collector->GetName() << " freed: " << freed_objects 696 << " objects with total size " << PrettySize(freed_bytes) << "\n" 697 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 698 << PrettySize(freed_bytes / seconds) << "/s\n"; 699 total_duration += total_ns; 700 total_paused_time += total_pause_ns; 701 } 702 collector->ResetMeasurements(); 703 } 704 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 705 if (total_duration != 0) { 706 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 707 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 708 os << "Mean GC size throughput: " 709 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 710 os << "Mean GC object throughput: " 711 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 712 } 713 size_t total_objects_allocated = GetObjectsAllocatedEver(); 714 os << "Total number of allocations: " << total_objects_allocated << "\n"; 715 size_t total_bytes_allocated = GetBytesAllocatedEver(); 716 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 717 if (kMeasureAllocationTime) { 718 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 719 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 720 << "\n"; 721 } 722 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 723 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 724 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 725} 726 727Heap::~Heap() { 728 VLOG(heap) << "Starting ~Heap()"; 729 STLDeleteElements(&garbage_collectors_); 730 // If we don't reset then the mark stack complains in its destructor. 731 allocation_stack_->Reset(); 732 live_stack_->Reset(); 733 STLDeleteValues(&mod_union_tables_); 734 STLDeleteValues(&remembered_sets_); 735 STLDeleteElements(&continuous_spaces_); 736 STLDeleteElements(&discontinuous_spaces_); 737 delete gc_complete_lock_; 738 delete heap_trim_request_lock_; 739 VLOG(heap) << "Finished ~Heap()"; 740} 741 742space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 743 bool fail_ok) const { 744 for (const auto& space : continuous_spaces_) { 745 if (space->Contains(obj)) { 746 return space; 747 } 748 } 749 if (!fail_ok) { 750 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 751 } 752 return NULL; 753} 754 755space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 756 bool fail_ok) const { 757 for (const auto& space : discontinuous_spaces_) { 758 if (space->Contains(obj)) { 759 return space; 760 } 761 } 762 if (!fail_ok) { 763 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 764 } 765 return NULL; 766} 767 768space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 769 space::Space* result = FindContinuousSpaceFromObject(obj, true); 770 if (result != NULL) { 771 return result; 772 } 773 return FindDiscontinuousSpaceFromObject(obj, true); 774} 775 776struct SoftReferenceArgs { 777 IsMarkedCallback* is_marked_callback_; 778 MarkObjectCallback* mark_callback_; 779 void* arg_; 780}; 781 782mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 783 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 784 // TODO: Not preserve all soft references. 785 return args->mark_callback_(obj, args->arg_); 786} 787 788void Heap::ProcessSoftReferences(TimingLogger& timings, bool clear_soft, 789 IsMarkedCallback* is_marked_callback, 790 MarkObjectCallback* mark_object_callback, 791 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 792 // Unless required to clear soft references with white references, preserve some white referents. 793 if (!clear_soft) { 794 // Don't clear for sticky GC. 795 SoftReferenceArgs soft_reference_args; 796 soft_reference_args.is_marked_callback_ = is_marked_callback; 797 soft_reference_args.mark_callback_ = mark_object_callback; 798 soft_reference_args.arg_ = arg; 799 // References with a marked referent are removed from the list. 800 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 801 &soft_reference_args); 802 process_mark_stack_callback(arg); 803 } 804} 805 806// Process reference class instances and schedule finalizations. 807void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 808 IsMarkedCallback* is_marked_callback, 809 MarkObjectCallback* mark_object_callback, 810 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 811 timings.StartSplit("(Paused)ProcessReferences"); 812 ProcessSoftReferences(timings, clear_soft, is_marked_callback, mark_object_callback, 813 process_mark_stack_callback, arg); 814 // Clear all remaining soft and weak references with white referents. 815 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 816 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 817 timings.EndSplit(); 818 // Preserve all white objects with finalize methods and schedule them for finalization. 819 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 820 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 821 mark_object_callback, arg); 822 process_mark_stack_callback(arg); 823 timings.EndSplit(); 824 timings.StartSplit("(Paused)ProcessReferences"); 825 // Clear all f-reachable soft and weak references with white referents. 826 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 827 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 828 // Clear all phantom references with white referents. 829 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 830 // At this point all reference queues other than the cleared references should be empty. 831 DCHECK(soft_reference_queue_.IsEmpty()); 832 DCHECK(weak_reference_queue_.IsEmpty()); 833 DCHECK(finalizer_reference_queue_.IsEmpty()); 834 DCHECK(phantom_reference_queue_.IsEmpty()); 835 timings.EndSplit(); 836} 837 838// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 839// marked, put it on the appropriate list in the heap for later processing. 840void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Reference* ref, 841 IsMarkedCallback is_marked_callback, void* arg) { 842 // klass can be the class of the old object if the visitor already updated the class of ref. 843 DCHECK(klass->IsReferenceClass()); 844 mirror::Object* referent = ref->GetReferent(); 845 if (referent != nullptr) { 846 mirror::Object* forward_address = is_marked_callback(referent, arg); 847 // Null means that the object is not currently marked. 848 if (forward_address == nullptr) { 849 Thread* self = Thread::Current(); 850 // TODO: Remove these locks, and use atomic stacks for storing references? 851 // We need to check that the references haven't already been enqueued since we can end up 852 // scanning the same reference multiple times due to dirty cards. 853 if (klass->IsSoftReferenceClass()) { 854 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 855 } else if (klass->IsWeakReferenceClass()) { 856 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 857 } else if (klass->IsFinalizerReferenceClass()) { 858 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 859 } else if (klass->IsPhantomReferenceClass()) { 860 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 861 } else { 862 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 863 << klass->GetAccessFlags(); 864 } 865 } else if (referent != forward_address) { 866 // Referent is already marked and we need to update it. 867 ref->SetReferent<false>(forward_address); 868 } 869 } 870} 871 872space::ImageSpace* Heap::GetImageSpace() const { 873 for (const auto& space : continuous_spaces_) { 874 if (space->IsImageSpace()) { 875 return space->AsImageSpace(); 876 } 877 } 878 return NULL; 879} 880 881static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 882 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 883 if (used_bytes < chunk_size) { 884 size_t chunk_free_bytes = chunk_size - used_bytes; 885 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 886 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 887 } 888} 889 890void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 891 std::ostringstream oss; 892 size_t total_bytes_free = GetFreeMemory(); 893 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 894 << " free bytes"; 895 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 896 if (!large_object_allocation && total_bytes_free >= byte_count) { 897 size_t max_contiguous_allocation = 0; 898 for (const auto& space : continuous_spaces_) { 899 if (space->IsMallocSpace()) { 900 // To allow the Walk/InspectAll() to exclusively-lock the mutator 901 // lock, temporarily release the shared access to the mutator 902 // lock here by transitioning to the suspended state. 903 Locks::mutator_lock_->AssertSharedHeld(self); 904 self->TransitionFromRunnableToSuspended(kSuspended); 905 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 906 self->TransitionFromSuspendedToRunnable(); 907 Locks::mutator_lock_->AssertSharedHeld(self); 908 } 909 } 910 oss << "; failed due to fragmentation (largest possible contiguous allocation " 911 << max_contiguous_allocation << " bytes)"; 912 } 913 self->ThrowOutOfMemoryError(oss.str().c_str()); 914} 915 916void Heap::DoPendingTransitionOrTrim() { 917 Thread* self = Thread::Current(); 918 CollectorType desired_collector_type; 919 // Wait until we reach the desired transition time. 920 while (true) { 921 uint64_t wait_time; 922 { 923 MutexLock mu(self, *heap_trim_request_lock_); 924 desired_collector_type = desired_collector_type_; 925 uint64_t current_time = NanoTime(); 926 if (current_time >= heap_transition_target_time_) { 927 break; 928 } 929 wait_time = heap_transition_target_time_ - current_time; 930 } 931 ScopedThreadStateChange tsc(self, kSleeping); 932 usleep(wait_time / 1000); // Usleep takes microseconds. 933 } 934 // Transition the collector if the desired collector type is not the same as the current 935 // collector type. 936 TransitionCollector(desired_collector_type); 937 if (!CareAboutPauseTimes()) { 938 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 939 // about pauses. 940 Runtime* runtime = Runtime::Current(); 941 runtime->GetThreadList()->SuspendAll(); 942 runtime->GetMonitorList()->DeflateMonitors(); 943 runtime->GetThreadList()->ResumeAll(); 944 // Do a heap trim if it is needed. 945 Trim(); 946 } 947} 948 949void Heap::Trim() { 950 Thread* self = Thread::Current(); 951 { 952 MutexLock mu(self, *heap_trim_request_lock_); 953 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 954 return; 955 } 956 last_trim_time_ = NanoTime(); 957 heap_trim_request_pending_ = false; 958 } 959 { 960 // Need to do this before acquiring the locks since we don't want to get suspended while 961 // holding any locks. 962 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 963 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 964 // trimming. 965 MutexLock mu(self, *gc_complete_lock_); 966 // Ensure there is only one GC at a time. 967 WaitForGcToCompleteLocked(self); 968 collector_type_running_ = kCollectorTypeHeapTrim; 969 } 970 uint64_t start_ns = NanoTime(); 971 // Trim the managed spaces. 972 uint64_t total_alloc_space_allocated = 0; 973 uint64_t total_alloc_space_size = 0; 974 uint64_t managed_reclaimed = 0; 975 for (const auto& space : continuous_spaces_) { 976 if (space->IsMallocSpace()) { 977 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 978 total_alloc_space_size += alloc_space->Size(); 979 managed_reclaimed += alloc_space->Trim(); 980 } 981 } 982 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 983 if (bump_pointer_space_ != nullptr) { 984 total_alloc_space_allocated -= bump_pointer_space_->Size(); 985 } 986 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 987 static_cast<float>(total_alloc_space_size); 988 uint64_t gc_heap_end_ns = NanoTime(); 989 // We never move things in the native heap, so we can finish the GC at this point. 990 FinishGC(self, collector::kGcTypeNone); 991 // Trim the native heap. 992 dlmalloc_trim(0); 993 size_t native_reclaimed = 0; 994 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 995 uint64_t end_ns = NanoTime(); 996 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 997 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 998 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 999 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1000 << "%."; 1001} 1002 1003bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1004 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1005 // taking the lock. 1006 if (obj == nullptr) { 1007 return true; 1008 } 1009 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1010} 1011 1012bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1013 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1014} 1015 1016bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1017 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1018 return false; 1019 } 1020 for (const auto& space : continuous_spaces_) { 1021 if (space->HasAddress(obj)) { 1022 return true; 1023 } 1024 } 1025 return false; 1026} 1027 1028bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1029 bool search_live_stack, bool sorted) { 1030 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1031 return false; 1032 } 1033 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1034 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1035 if (obj == klass) { 1036 // This case happens for java.lang.Class. 1037 return true; 1038 } 1039 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1040 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1041 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1042 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1043 return temp_space_->Contains(obj); 1044 } 1045 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1046 space::DiscontinuousSpace* d_space = NULL; 1047 if (c_space != nullptr) { 1048 if (c_space->GetLiveBitmap()->Test(obj)) { 1049 return true; 1050 } 1051 } else { 1052 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1053 if (d_space != nullptr) { 1054 if (d_space->GetLiveObjects()->Test(obj)) { 1055 return true; 1056 } 1057 } 1058 } 1059 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1060 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1061 if (i > 0) { 1062 NanoSleep(MsToNs(10)); 1063 } 1064 if (search_allocation_stack) { 1065 if (sorted) { 1066 if (allocation_stack_->ContainsSorted(obj)) { 1067 return true; 1068 } 1069 } else if (allocation_stack_->Contains(obj)) { 1070 return true; 1071 } 1072 } 1073 1074 if (search_live_stack) { 1075 if (sorted) { 1076 if (live_stack_->ContainsSorted(obj)) { 1077 return true; 1078 } 1079 } else if (live_stack_->Contains(obj)) { 1080 return true; 1081 } 1082 } 1083 } 1084 // We need to check the bitmaps again since there is a race where we mark something as live and 1085 // then clear the stack containing it. 1086 if (c_space != nullptr) { 1087 if (c_space->GetLiveBitmap()->Test(obj)) { 1088 return true; 1089 } 1090 } else { 1091 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1092 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 1093 return true; 1094 } 1095 } 1096 return false; 1097} 1098 1099void Heap::DumpSpaces(std::ostream& stream) { 1100 for (const auto& space : continuous_spaces_) { 1101 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1102 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1103 stream << space << " " << *space << "\n"; 1104 if (live_bitmap != nullptr) { 1105 stream << live_bitmap << " " << *live_bitmap << "\n"; 1106 } 1107 if (mark_bitmap != nullptr) { 1108 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1109 } 1110 } 1111 for (const auto& space : discontinuous_spaces_) { 1112 stream << space << " " << *space << "\n"; 1113 } 1114} 1115 1116void Heap::VerifyObjectBody(mirror::Object* obj) { 1117 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1118 return; 1119 } 1120 // Ignore early dawn of the universe verifications. 1121 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 1122 return; 1123 } 1124 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1125 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 1126 mirror::Object::ClassOffset(), false); 1127 CHECK(c != nullptr) << "Null class in object " << obj; 1128 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1129 CHECK(VerifyClassClass(c)); 1130 1131 if (verify_object_mode_ > kVerifyObjectModeFast) { 1132 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1133 if (!IsLiveObjectLocked(obj)) { 1134 DumpSpaces(); 1135 LOG(FATAL) << "Object is dead: " << obj; 1136 } 1137 } 1138} 1139 1140void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1141 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1142} 1143 1144void Heap::VerifyHeap() { 1145 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1146 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1147} 1148 1149void Heap::RecordFree(ssize_t freed_objects, ssize_t freed_bytes) { 1150 // Use signed comparison since freed bytes can be negative when background compaction foreground 1151 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1152 // free list backed space typically increasing memory footprint due to padding and binning. 1153 DCHECK_LE(freed_bytes, static_cast<ssize_t>(num_bytes_allocated_.Load())); 1154 DCHECK_GE(freed_objects, 0); 1155 num_bytes_allocated_.FetchAndSub(freed_bytes); 1156 if (Runtime::Current()->HasStatsEnabled()) { 1157 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1158 thread_stats->freed_objects += freed_objects; 1159 thread_stats->freed_bytes += freed_bytes; 1160 // TODO: Do this concurrently. 1161 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1162 global_stats->freed_objects += freed_objects; 1163 global_stats->freed_bytes += freed_bytes; 1164 } 1165} 1166 1167mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1168 size_t alloc_size, size_t* bytes_allocated, 1169 size_t* usable_size, 1170 mirror::Class** klass) { 1171 mirror::Object* ptr = nullptr; 1172 bool was_default_allocator = allocator == GetCurrentAllocator(); 1173 DCHECK(klass != nullptr); 1174 SirtRef<mirror::Class> sirt_klass(self, *klass); 1175 // The allocation failed. If the GC is running, block until it completes, and then retry the 1176 // allocation. 1177 collector::GcType last_gc = WaitForGcToComplete(self); 1178 if (last_gc != collector::kGcTypeNone) { 1179 // If we were the default allocator but the allocator changed while we were suspended, 1180 // abort the allocation. 1181 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1182 *klass = sirt_klass.get(); 1183 return nullptr; 1184 } 1185 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1186 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1187 } 1188 1189 collector::GcType tried_type = next_gc_type_; 1190 if (ptr == nullptr) { 1191 const bool gc_ran = 1192 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1193 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1194 *klass = sirt_klass.get(); 1195 return nullptr; 1196 } 1197 if (gc_ran) { 1198 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1199 } 1200 } 1201 1202 // Loop through our different Gc types and try to Gc until we get enough free memory. 1203 for (collector::GcType gc_type : gc_plan_) { 1204 if (ptr != nullptr) { 1205 break; 1206 } 1207 if (gc_type == tried_type) { 1208 continue; 1209 } 1210 // Attempt to run the collector, if we succeed, re-try the allocation. 1211 const bool gc_ran = 1212 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1213 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1214 *klass = sirt_klass.get(); 1215 return nullptr; 1216 } 1217 if (gc_ran) { 1218 // Did we free sufficient memory for the allocation to succeed? 1219 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1220 } 1221 } 1222 // Allocations have failed after GCs; this is an exceptional state. 1223 if (ptr == nullptr) { 1224 // Try harder, growing the heap if necessary. 1225 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1226 } 1227 if (ptr == nullptr) { 1228 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1229 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1230 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1231 // OOME. 1232 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1233 << " allocation"; 1234 // TODO: Run finalization, but this may cause more allocations to occur. 1235 // We don't need a WaitForGcToComplete here either. 1236 DCHECK(!gc_plan_.empty()); 1237 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1238 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1239 *klass = sirt_klass.get(); 1240 return nullptr; 1241 } 1242 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1243 if (ptr == nullptr) { 1244 ThrowOutOfMemoryError(self, alloc_size, false); 1245 } 1246 } 1247 *klass = sirt_klass.get(); 1248 return ptr; 1249} 1250 1251void Heap::SetTargetHeapUtilization(float target) { 1252 DCHECK_GT(target, 0.0f); // asserted in Java code 1253 DCHECK_LT(target, 1.0f); 1254 target_utilization_ = target; 1255} 1256 1257size_t Heap::GetObjectsAllocated() const { 1258 size_t total = 0; 1259 for (space::AllocSpace* space : alloc_spaces_) { 1260 total += space->GetObjectsAllocated(); 1261 } 1262 return total; 1263} 1264 1265size_t Heap::GetObjectsAllocatedEver() const { 1266 return GetObjectsFreedEver() + GetObjectsAllocated(); 1267} 1268 1269size_t Heap::GetBytesAllocatedEver() const { 1270 return GetBytesFreedEver() + GetBytesAllocated(); 1271} 1272 1273class InstanceCounter { 1274 public: 1275 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1276 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1277 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1278 } 1279 static void Callback(mirror::Object* obj, void* arg) 1280 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1281 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1282 mirror::Class* instance_class = obj->GetClass(); 1283 CHECK(instance_class != nullptr); 1284 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1285 if (instance_counter->use_is_assignable_from_) { 1286 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1287 ++instance_counter->counts_[i]; 1288 } 1289 } else if (instance_class == instance_counter->classes_[i]) { 1290 ++instance_counter->counts_[i]; 1291 } 1292 } 1293 } 1294 1295 private: 1296 const std::vector<mirror::Class*>& classes_; 1297 bool use_is_assignable_from_; 1298 uint64_t* const counts_; 1299 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1300}; 1301 1302void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1303 uint64_t* counts) { 1304 // Can't do any GC in this function since this may move classes. 1305 Thread* self = Thread::Current(); 1306 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1307 InstanceCounter counter(classes, use_is_assignable_from, counts); 1308 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1309 VisitObjects(InstanceCounter::Callback, &counter); 1310 self->EndAssertNoThreadSuspension(old_cause); 1311} 1312 1313class InstanceCollector { 1314 public: 1315 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1316 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1317 : class_(c), max_count_(max_count), instances_(instances) { 1318 } 1319 static void Callback(mirror::Object* obj, void* arg) 1320 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1321 DCHECK(arg != nullptr); 1322 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1323 mirror::Class* instance_class = obj->GetClass(); 1324 if (instance_class == instance_collector->class_) { 1325 if (instance_collector->max_count_ == 0 || 1326 instance_collector->instances_.size() < instance_collector->max_count_) { 1327 instance_collector->instances_.push_back(obj); 1328 } 1329 } 1330 } 1331 1332 private: 1333 mirror::Class* class_; 1334 uint32_t max_count_; 1335 std::vector<mirror::Object*>& instances_; 1336 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1337}; 1338 1339void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1340 std::vector<mirror::Object*>& instances) { 1341 // Can't do any GC in this function since this may move classes. 1342 Thread* self = Thread::Current(); 1343 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1344 InstanceCollector collector(c, max_count, instances); 1345 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1346 VisitObjects(&InstanceCollector::Callback, &collector); 1347 self->EndAssertNoThreadSuspension(old_cause); 1348} 1349 1350class ReferringObjectsFinder { 1351 public: 1352 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1353 std::vector<mirror::Object*>& referring_objects) 1354 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1355 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1356 } 1357 1358 static void Callback(mirror::Object* obj, void* arg) 1359 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1360 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1361 } 1362 1363 // For bitmap Visit. 1364 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1365 // annotalysis on visitors. 1366 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1367 o->VisitReferences<true>(*this); 1368 } 1369 1370 // For Object::VisitReferences. 1371 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1372 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1373 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 1374 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1375 referring_objects_.push_back(obj); 1376 } 1377 } 1378 1379 private: 1380 mirror::Object* object_; 1381 uint32_t max_count_; 1382 std::vector<mirror::Object*>& referring_objects_; 1383 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1384}; 1385 1386void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1387 std::vector<mirror::Object*>& referring_objects) { 1388 // Can't do any GC in this function since this may move the object o. 1389 Thread* self = Thread::Current(); 1390 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1391 ReferringObjectsFinder finder(o, max_count, referring_objects); 1392 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1393 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1394 self->EndAssertNoThreadSuspension(old_cause); 1395} 1396 1397void Heap::CollectGarbage(bool clear_soft_references) { 1398 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1399 // last GC will not have necessarily been cleared. 1400 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1401} 1402 1403void Heap::TransitionCollector(CollectorType collector_type) { 1404 if (collector_type == collector_type_) { 1405 return; 1406 } 1407 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1408 << " -> " << static_cast<int>(collector_type); 1409 uint64_t start_time = NanoTime(); 1410 uint32_t before_size = GetTotalMemory(); 1411 uint32_t before_allocated = num_bytes_allocated_.Load(); 1412 ThreadList* tl = Runtime::Current()->GetThreadList(); 1413 Thread* self = Thread::Current(); 1414 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1415 Locks::mutator_lock_->AssertNotHeld(self); 1416 const bool copying_transition = 1417 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1418 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1419 // compacting_gc_disable_count_, this should rarely occurs). 1420 for (;;) { 1421 { 1422 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1423 MutexLock mu(self, *gc_complete_lock_); 1424 // Ensure there is only one GC at a time. 1425 WaitForGcToCompleteLocked(self); 1426 // If someone else beat us to it and changed the collector before we could, exit. 1427 // This is safe to do before the suspend all since we set the collector_type_running_ before 1428 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1429 // then it would get blocked on WaitForGcToCompleteLocked. 1430 if (collector_type == collector_type_) { 1431 return; 1432 } 1433 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1434 if (!copying_transition || disable_moving_gc_count_ == 0) { 1435 // TODO: Not hard code in semi-space collector? 1436 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1437 break; 1438 } 1439 } 1440 usleep(1000); 1441 } 1442 tl->SuspendAll(); 1443 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1444 switch (collector_type) { 1445 case kCollectorTypeSS: 1446 // Fall-through. 1447 case kCollectorTypeGSS: { 1448 if (!IsMovingGc(collector_type_)) { 1449 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1450 // pointer space last transition it will be protected. 1451 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1452 Compact(bump_pointer_space_, main_space_); 1453 } 1454 break; 1455 } 1456 case kCollectorTypeMS: 1457 // Fall through. 1458 case kCollectorTypeCMS: { 1459 if (IsMovingGc(collector_type_)) { 1460 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1461 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1462 Compact(main_space_, bump_pointer_space_); 1463 } 1464 break; 1465 } 1466 default: { 1467 LOG(FATAL) << "Attempted to transition to invalid collector type " 1468 << static_cast<size_t>(collector_type); 1469 break; 1470 } 1471 } 1472 ChangeCollector(collector_type); 1473 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1474 tl->ResumeAll(); 1475 // Can't call into java code with all threads suspended. 1476 EnqueueClearedReferences(); 1477 uint64_t duration = NanoTime() - start_time; 1478 GrowForUtilization(semi_space_collector_); 1479 FinishGC(self, collector::kGcTypeFull); 1480 int32_t after_size = GetTotalMemory(); 1481 int32_t delta_size = before_size - after_size; 1482 int32_t after_allocated = num_bytes_allocated_.Load(); 1483 int32_t delta_allocated = before_allocated - after_allocated; 1484 const std::string saved_bytes_str = 1485 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1486 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1487 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1488 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1489 << PrettySize(delta_size) << " saved"; 1490} 1491 1492void Heap::ChangeCollector(CollectorType collector_type) { 1493 // TODO: Only do this with all mutators suspended to avoid races. 1494 if (collector_type != collector_type_) { 1495 collector_type_ = collector_type; 1496 gc_plan_.clear(); 1497 switch (collector_type_) { 1498 case kCollectorTypeCC: // Fall-through. 1499 case kCollectorTypeSS: // Fall-through. 1500 case kCollectorTypeGSS: { 1501 gc_plan_.push_back(collector::kGcTypeFull); 1502 if (use_tlab_) { 1503 ChangeAllocator(kAllocatorTypeTLAB); 1504 } else { 1505 ChangeAllocator(kAllocatorTypeBumpPointer); 1506 } 1507 break; 1508 } 1509 case kCollectorTypeMS: { 1510 gc_plan_.push_back(collector::kGcTypeSticky); 1511 gc_plan_.push_back(collector::kGcTypePartial); 1512 gc_plan_.push_back(collector::kGcTypeFull); 1513 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1514 break; 1515 } 1516 case kCollectorTypeCMS: { 1517 gc_plan_.push_back(collector::kGcTypeSticky); 1518 gc_plan_.push_back(collector::kGcTypePartial); 1519 gc_plan_.push_back(collector::kGcTypeFull); 1520 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1521 break; 1522 } 1523 default: { 1524 LOG(FATAL) << "Unimplemented"; 1525 } 1526 } 1527 if (IsGcConcurrent()) { 1528 concurrent_start_bytes_ = 1529 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1530 } else { 1531 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1532 } 1533 } 1534} 1535 1536// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1537class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1538 public: 1539 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1540 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1541 } 1542 1543 void BuildBins(space::ContinuousSpace* space) { 1544 bin_live_bitmap_ = space->GetLiveBitmap(); 1545 bin_mark_bitmap_ = space->GetMarkBitmap(); 1546 BinContext context; 1547 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1548 context.collector_ = this; 1549 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1550 // Note: This requires traversing the space in increasing order of object addresses. 1551 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1552 // Add the last bin which spans after the last object to the end of the space. 1553 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1554 } 1555 1556 private: 1557 struct BinContext { 1558 uintptr_t prev_; // The end of the previous object. 1559 ZygoteCompactingCollector* collector_; 1560 }; 1561 // Maps from bin sizes to locations. 1562 std::multimap<size_t, uintptr_t> bins_; 1563 // Live bitmap of the space which contains the bins. 1564 accounting::SpaceBitmap* bin_live_bitmap_; 1565 // Mark bitmap of the space which contains the bins. 1566 accounting::SpaceBitmap* bin_mark_bitmap_; 1567 1568 static void Callback(mirror::Object* obj, void* arg) 1569 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1570 DCHECK(arg != nullptr); 1571 BinContext* context = reinterpret_cast<BinContext*>(arg); 1572 ZygoteCompactingCollector* collector = context->collector_; 1573 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1574 size_t bin_size = object_addr - context->prev_; 1575 // Add the bin consisting of the end of the previous object to the start of the current object. 1576 collector->AddBin(bin_size, context->prev_); 1577 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1578 } 1579 1580 void AddBin(size_t size, uintptr_t position) { 1581 if (size != 0) { 1582 bins_.insert(std::make_pair(size, position)); 1583 } 1584 } 1585 1586 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1587 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1588 // allocator. 1589 return false; 1590 } 1591 1592 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1593 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1594 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1595 mirror::Object* forward_address; 1596 // Find the smallest bin which we can move obj in. 1597 auto it = bins_.lower_bound(object_size); 1598 if (it == bins_.end()) { 1599 // No available space in the bins, place it in the target space instead (grows the zygote 1600 // space). 1601 size_t bytes_allocated; 1602 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1603 if (to_space_live_bitmap_ != nullptr) { 1604 to_space_live_bitmap_->Set(forward_address); 1605 } else { 1606 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1607 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1608 } 1609 } else { 1610 size_t size = it->first; 1611 uintptr_t pos = it->second; 1612 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1613 forward_address = reinterpret_cast<mirror::Object*>(pos); 1614 // Set the live and mark bits so that sweeping system weaks works properly. 1615 bin_live_bitmap_->Set(forward_address); 1616 bin_mark_bitmap_->Set(forward_address); 1617 DCHECK_GE(size, object_size); 1618 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1619 } 1620 // Copy the object over to its new location. 1621 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1622 if (kUseBakerOrBrooksReadBarrier) { 1623 obj->AssertReadBarrierPointer(); 1624 if (kUseBrooksReadBarrier) { 1625 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1626 forward_address->SetReadBarrierPointer(forward_address); 1627 } 1628 forward_address->AssertReadBarrierPointer(); 1629 } 1630 return forward_address; 1631 } 1632}; 1633 1634void Heap::UnBindBitmaps() { 1635 for (const auto& space : GetContinuousSpaces()) { 1636 if (space->IsContinuousMemMapAllocSpace()) { 1637 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1638 if (alloc_space->HasBoundBitmaps()) { 1639 alloc_space->UnBindBitmaps(); 1640 } 1641 } 1642 } 1643} 1644 1645void Heap::PreZygoteFork() { 1646 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1647 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1648 Thread* self = Thread::Current(); 1649 MutexLock mu(self, zygote_creation_lock_); 1650 // Try to see if we have any Zygote spaces. 1651 if (have_zygote_space_) { 1652 return; 1653 } 1654 VLOG(heap) << "Starting PreZygoteFork"; 1655 // Trim the pages at the end of the non moving space. 1656 non_moving_space_->Trim(); 1657 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1658 // there. 1659 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1660 // Change the collector to the post zygote one. 1661 if (kCompactZygote) { 1662 DCHECK(semi_space_collector_ != nullptr); 1663 // Temporarily disable rosalloc verification because the zygote 1664 // compaction will mess up the rosalloc internal metadata. 1665 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1666 ZygoteCompactingCollector zygote_collector(this); 1667 zygote_collector.BuildBins(non_moving_space_); 1668 // Create a new bump pointer space which we will compact into. 1669 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1670 non_moving_space_->Limit()); 1671 // Compact the bump pointer space to a new zygote bump pointer space. 1672 bool reset_main_space = false; 1673 if (IsMovingGc(collector_type_)) { 1674 zygote_collector.SetFromSpace(bump_pointer_space_); 1675 } else { 1676 CHECK(main_space_ != nullptr); 1677 // Copy from the main space. 1678 zygote_collector.SetFromSpace(main_space_); 1679 reset_main_space = true; 1680 } 1681 zygote_collector.SetToSpace(&target_space); 1682 1683 Runtime::Current()->GetThreadList()->SuspendAll(); 1684 zygote_collector.Run(kGcCauseCollectorTransition, false); 1685 if (IsMovingGc(collector_type_)) { 1686 SwapSemiSpaces(); 1687 } 1688 Runtime::Current()->GetThreadList()->ResumeAll(); 1689 1690 if (reset_main_space) { 1691 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1692 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1693 MemMap* mem_map = main_space_->ReleaseMemMap(); 1694 RemoveSpace(main_space_); 1695 delete main_space_; 1696 main_space_ = nullptr; 1697 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1698 AddSpace(main_space_); 1699 } else { 1700 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1701 } 1702 if (temp_space_ != nullptr) { 1703 CHECK(temp_space_->IsEmpty()); 1704 } 1705 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1706 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1707 // Update the end and write out image. 1708 non_moving_space_->SetEnd(target_space.End()); 1709 non_moving_space_->SetLimit(target_space.Limit()); 1710 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1711 } 1712 ChangeCollector(foreground_collector_type_); 1713 // Save the old space so that we can remove it after we complete creating the zygote space. 1714 space::MallocSpace* old_alloc_space = non_moving_space_; 1715 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1716 // the remaining available space. 1717 // Remove the old space before creating the zygote space since creating the zygote space sets 1718 // the old alloc space's bitmaps to nullptr. 1719 RemoveSpace(old_alloc_space); 1720 if (collector::SemiSpace::kUseRememberedSet) { 1721 // Sanity bound check. 1722 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1723 // Remove the remembered set for the now zygote space (the old 1724 // non-moving space). Note now that we have compacted objects into 1725 // the zygote space, the data in the remembered set is no longer 1726 // needed. The zygote space will instead have a mod-union table 1727 // from this point on. 1728 RemoveRememberedSet(old_alloc_space); 1729 } 1730 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1731 low_memory_mode_, 1732 &non_moving_space_); 1733 delete old_alloc_space; 1734 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1735 AddSpace(zygote_space, false); 1736 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1737 AddSpace(non_moving_space_); 1738 have_zygote_space_ = true; 1739 // Enable large object space allocations. 1740 large_object_threshold_ = kDefaultLargeObjectThreshold; 1741 // Create the zygote space mod union table. 1742 accounting::ModUnionTable* mod_union_table = 1743 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1744 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1745 AddModUnionTable(mod_union_table); 1746 if (collector::SemiSpace::kUseRememberedSet) { 1747 // Add a new remembered set for the post-zygote non-moving space. 1748 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1749 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1750 non_moving_space_); 1751 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1752 << "Failed to create post-zygote non-moving space remembered set"; 1753 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1754 } 1755} 1756 1757void Heap::FlushAllocStack() { 1758 MarkAllocStackAsLive(allocation_stack_.get()); 1759 allocation_stack_->Reset(); 1760} 1761 1762void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1763 accounting::SpaceBitmap* bitmap2, 1764 accounting::ObjectSet* large_objects, 1765 accounting::ObjectStack* stack) { 1766 DCHECK(bitmap1 != nullptr); 1767 DCHECK(bitmap2 != nullptr); 1768 mirror::Object** limit = stack->End(); 1769 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1770 const mirror::Object* obj = *it; 1771 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1772 if (bitmap1->HasAddress(obj)) { 1773 bitmap1->Set(obj); 1774 } else if (bitmap2->HasAddress(obj)) { 1775 bitmap2->Set(obj); 1776 } else { 1777 large_objects->Set(obj); 1778 } 1779 } 1780 } 1781} 1782 1783void Heap::SwapSemiSpaces() { 1784 CHECK(bump_pointer_space_ != nullptr); 1785 CHECK(temp_space_ != nullptr); 1786 std::swap(bump_pointer_space_, temp_space_); 1787} 1788 1789void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1790 space::ContinuousMemMapAllocSpace* source_space) { 1791 CHECK(kMovingCollector); 1792 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1793 if (target_space != source_space) { 1794 semi_space_collector_->SetFromSpace(source_space); 1795 semi_space_collector_->SetToSpace(target_space); 1796 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1797 } 1798} 1799 1800collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1801 bool clear_soft_references) { 1802 Thread* self = Thread::Current(); 1803 Runtime* runtime = Runtime::Current(); 1804 // If the heap can't run the GC, silently fail and return that no GC was run. 1805 switch (gc_type) { 1806 case collector::kGcTypePartial: { 1807 if (!have_zygote_space_) { 1808 return collector::kGcTypeNone; 1809 } 1810 break; 1811 } 1812 default: { 1813 // Other GC types don't have any special cases which makes them not runnable. The main case 1814 // here is full GC. 1815 } 1816 } 1817 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1818 Locks::mutator_lock_->AssertNotHeld(self); 1819 if (self->IsHandlingStackOverflow()) { 1820 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1821 } 1822 bool compacting_gc; 1823 { 1824 gc_complete_lock_->AssertNotHeld(self); 1825 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1826 MutexLock mu(self, *gc_complete_lock_); 1827 // Ensure there is only one GC at a time. 1828 WaitForGcToCompleteLocked(self); 1829 compacting_gc = IsMovingGc(collector_type_); 1830 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1831 if (compacting_gc && disable_moving_gc_count_ != 0) { 1832 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1833 return collector::kGcTypeNone; 1834 } 1835 collector_type_running_ = collector_type_; 1836 } 1837 1838 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1839 ++runtime->GetStats()->gc_for_alloc_count; 1840 ++self->GetStats()->gc_for_alloc_count; 1841 } 1842 uint64_t gc_start_time_ns = NanoTime(); 1843 uint64_t gc_start_size = GetBytesAllocated(); 1844 // Approximate allocation rate in bytes / second. 1845 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1846 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1847 if (LIKELY(ms_delta != 0)) { 1848 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1849 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1850 } 1851 1852 DCHECK_LT(gc_type, collector::kGcTypeMax); 1853 DCHECK_NE(gc_type, collector::kGcTypeNone); 1854 1855 collector::GarbageCollector* collector = nullptr; 1856 // TODO: Clean this up. 1857 if (compacting_gc) { 1858 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1859 current_allocator_ == kAllocatorTypeTLAB); 1860 if (collector_type_ == kCollectorTypeSS || collector_type_ == kCollectorTypeGSS) { 1861 gc_type = semi_space_collector_->GetGcType(); 1862 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1863 semi_space_collector_->SetToSpace(temp_space_); 1864 collector = semi_space_collector_; 1865 } else if (collector_type_ == kCollectorTypeCC) { 1866 gc_type = concurrent_copying_collector_->GetGcType(); 1867 collector = concurrent_copying_collector_; 1868 } else { 1869 LOG(FATAL) << "Unreachable - invalid collector type " << static_cast<size_t>(collector_type_); 1870 } 1871 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1872 CHECK(temp_space_->IsEmpty()); 1873 gc_type = collector::kGcTypeFull; 1874 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1875 current_allocator_ == kAllocatorTypeDlMalloc) { 1876 collector = FindCollectorByGcType(gc_type); 1877 } else { 1878 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1879 } 1880 CHECK(collector != nullptr) 1881 << "Could not find garbage collector with collector_type=" 1882 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1883 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1884 if (compacting_gc) { 1885 runtime->GetThreadList()->SuspendAll(); 1886 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1887 SwapSemiSpaces(); 1888 runtime->GetThreadList()->ResumeAll(); 1889 } else { 1890 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1891 } 1892 total_objects_freed_ever_ += collector->GetFreedObjects(); 1893 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1894 RequestHeapTrim(); 1895 // Enqueue cleared references. 1896 EnqueueClearedReferences(); 1897 // Grow the heap so that we know when to perform the next GC. 1898 GrowForUtilization(collector); 1899 if (CareAboutPauseTimes()) { 1900 const size_t duration = collector->GetDurationNs(); 1901 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1902 // GC for alloc pauses the allocating thread, so consider it as a pause. 1903 bool was_slow = duration > long_gc_log_threshold_ || 1904 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1905 if (!was_slow) { 1906 for (uint64_t pause : pauses) { 1907 was_slow = was_slow || pause > long_pause_log_threshold_; 1908 } 1909 } 1910 if (was_slow) { 1911 const size_t percent_free = GetPercentFree(); 1912 const size_t current_heap_size = GetBytesAllocated(); 1913 const size_t total_memory = GetTotalMemory(); 1914 std::ostringstream pause_string; 1915 for (size_t i = 0; i < pauses.size(); ++i) { 1916 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1917 << ((i != pauses.size() - 1) ? ", " : ""); 1918 } 1919 LOG(INFO) << gc_cause << " " << collector->GetName() 1920 << " GC freed " << collector->GetFreedObjects() << "(" 1921 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1922 << collector->GetFreedLargeObjects() << "(" 1923 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1924 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1925 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1926 << " total " << PrettyDuration((duration / 1000) * 1000); 1927 VLOG(heap) << ConstDumpable<TimingLogger>(collector->GetTimings()); 1928 } 1929 } 1930 FinishGC(self, gc_type); 1931 ATRACE_END(); 1932 1933 // Inform DDMS that a GC completed. 1934 Dbg::GcDidFinish(); 1935 return gc_type; 1936} 1937 1938void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1939 MutexLock mu(self, *gc_complete_lock_); 1940 collector_type_running_ = kCollectorTypeNone; 1941 if (gc_type != collector::kGcTypeNone) { 1942 last_gc_type_ = gc_type; 1943 } 1944 // Wake anyone who may have been waiting for the GC to complete. 1945 gc_complete_cond_->Broadcast(self); 1946} 1947 1948static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1949 RootType /*root_type*/) { 1950 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1951 if (*root == obj) { 1952 LOG(INFO) << "Object " << obj << " is a root"; 1953 } 1954} 1955 1956class ScanVisitor { 1957 public: 1958 void operator()(const mirror::Object* obj) const { 1959 LOG(ERROR) << "Would have rescanned object " << obj; 1960 } 1961}; 1962 1963// Verify a reference from an object. 1964class VerifyReferenceVisitor { 1965 public: 1966 explicit VerifyReferenceVisitor(Heap* heap) 1967 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1968 : heap_(heap), failed_(false) {} 1969 1970 bool Failed() const { 1971 return failed_; 1972 } 1973 1974 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1975 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1976 this->operator()(ref, mirror::Reference::ReferentOffset(), false); 1977 } 1978 1979 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1980 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1981 this->operator()(obj, obj->GetFieldObject<mirror::Object>(offset, false), offset); 1982 } 1983 1984 // TODO: Fix the no thread safety analysis. 1985 void operator()(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1986 NO_THREAD_SAFETY_ANALYSIS { 1987 if (ref == nullptr || IsLive(ref)) { 1988 // Verify that the reference is live. 1989 return; 1990 } 1991 if (!failed_) { 1992 // Print message on only on first failure to prevent spam. 1993 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1994 failed_ = true; 1995 } 1996 if (obj != nullptr) { 1997 accounting::CardTable* card_table = heap_->GetCardTable(); 1998 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1999 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2000 byte* card_addr = card_table->CardFromAddr(obj); 2001 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2002 << offset << "\n card value = " << static_cast<int>(*card_addr); 2003 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2004 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2005 } else { 2006 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2007 } 2008 2009 // Attmept to find the class inside of the recently freed objects. 2010 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2011 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2012 space::MallocSpace* space = ref_space->AsMallocSpace(); 2013 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2014 if (ref_class != nullptr) { 2015 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2016 << PrettyClass(ref_class); 2017 } else { 2018 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2019 } 2020 } 2021 2022 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2023 ref->GetClass()->IsClass()) { 2024 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2025 } else { 2026 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2027 << ") is not a valid heap address"; 2028 } 2029 2030 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2031 void* cover_begin = card_table->AddrFromCard(card_addr); 2032 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2033 accounting::CardTable::kCardSize); 2034 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2035 << "-" << cover_end; 2036 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2037 2038 if (bitmap == nullptr) { 2039 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2040 if (!VerifyClassClass(obj->GetClass())) { 2041 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2042 } 2043 } else { 2044 // Print out how the object is live. 2045 if (bitmap->Test(obj)) { 2046 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2047 } 2048 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2049 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2050 } 2051 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2052 LOG(ERROR) << "Object " << obj << " found in live stack"; 2053 } 2054 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2055 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2056 } 2057 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2058 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2059 } 2060 // Attempt to see if the card table missed the reference. 2061 ScanVisitor scan_visitor; 2062 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2063 card_table->Scan(bitmap, byte_cover_begin, 2064 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2065 } 2066 2067 // Search to see if any of the roots reference our object. 2068 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2069 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2070 2071 // Search to see if any of the roots reference our reference. 2072 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2073 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2074 } else { 2075 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 2076 } 2077 } 2078 2079 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2080 return heap_->IsLiveObjectLocked(obj, true, false, true); 2081 } 2082 2083 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2084 RootType /*root_type*/) { 2085 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2086 (*visitor)(nullptr, *root, MemberOffset(0)); 2087 } 2088 2089 private: 2090 Heap* const heap_; 2091 mutable bool failed_; 2092}; 2093 2094// Verify all references within an object, for use with HeapBitmap::Visit. 2095class VerifyObjectVisitor { 2096 public: 2097 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 2098 2099 void operator()(mirror::Object* obj) const 2100 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2101 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2102 // be live or else how did we find it in the live bitmap? 2103 VerifyReferenceVisitor visitor(heap_); 2104 // The class doesn't count as a reference but we should verify it anyways. 2105 obj->VisitReferences<true>(visitor, visitor); 2106 failed_ = failed_ || visitor.Failed(); 2107 } 2108 2109 static void VisitCallback(mirror::Object* obj, void* arg) 2110 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2111 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2112 visitor->operator()(obj); 2113 } 2114 2115 bool Failed() const { 2116 return failed_; 2117 } 2118 2119 private: 2120 Heap* const heap_; 2121 mutable bool failed_; 2122}; 2123 2124// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2125bool Heap::VerifyHeapReferences() { 2126 Thread* self = Thread::Current(); 2127 Locks::mutator_lock_->AssertExclusiveHeld(self); 2128 // Lets sort our allocation stacks so that we can efficiently binary search them. 2129 allocation_stack_->Sort(); 2130 live_stack_->Sort(); 2131 // Since we sorted the allocation stack content, need to revoke all 2132 // thread-local allocation stacks. 2133 RevokeAllThreadLocalAllocationStacks(self); 2134 VerifyObjectVisitor visitor(this); 2135 // Verify objects in the allocation stack since these will be objects which were: 2136 // 1. Allocated prior to the GC (pre GC verification). 2137 // 2. Allocated during the GC (pre sweep GC verification). 2138 // We don't want to verify the objects in the live stack since they themselves may be 2139 // pointing to dead objects if they are not reachable. 2140 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2141 // Verify the roots: 2142 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor); 2143 if (visitor.Failed()) { 2144 // Dump mod-union tables. 2145 for (const auto& table_pair : mod_union_tables_) { 2146 accounting::ModUnionTable* mod_union_table = table_pair.second; 2147 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2148 } 2149 // Dump remembered sets. 2150 for (const auto& table_pair : remembered_sets_) { 2151 accounting::RememberedSet* remembered_set = table_pair.second; 2152 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2153 } 2154 DumpSpaces(); 2155 return false; 2156 } 2157 return true; 2158} 2159 2160class VerifyReferenceCardVisitor { 2161 public: 2162 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2163 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2164 Locks::heap_bitmap_lock_) 2165 : heap_(heap), failed_(failed) { 2166 } 2167 2168 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2169 // annotalysis on visitors. 2170 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2171 NO_THREAD_SAFETY_ANALYSIS { 2172 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 2173 // Filter out class references since changing an object's class does not mark the card as dirty. 2174 // Also handles large objects, since the only reference they hold is a class reference. 2175 if (ref != nullptr && !ref->IsClass()) { 2176 accounting::CardTable* card_table = heap_->GetCardTable(); 2177 // If the object is not dirty and it is referencing something in the live stack other than 2178 // class, then it must be on a dirty card. 2179 if (!card_table->AddrIsInCardTable(obj)) { 2180 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2181 *failed_ = true; 2182 } else if (!card_table->IsDirty(obj)) { 2183 // TODO: Check mod-union tables. 2184 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2185 // kCardDirty - 1 if it didnt get touched since we aged it. 2186 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2187 if (live_stack->ContainsSorted(ref)) { 2188 if (live_stack->ContainsSorted(obj)) { 2189 LOG(ERROR) << "Object " << obj << " found in live stack"; 2190 } 2191 if (heap_->GetLiveBitmap()->Test(obj)) { 2192 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2193 } 2194 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2195 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2196 2197 // Print which field of the object is dead. 2198 if (!obj->IsObjectArray()) { 2199 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2200 CHECK(klass != NULL); 2201 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2202 : klass->GetIFields(); 2203 CHECK(fields != NULL); 2204 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2205 mirror::ArtField* cur = fields->Get(i); 2206 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2207 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2208 << PrettyField(cur); 2209 break; 2210 } 2211 } 2212 } else { 2213 mirror::ObjectArray<mirror::Object>* object_array = 2214 obj->AsObjectArray<mirror::Object>(); 2215 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2216 if (object_array->Get(i) == ref) { 2217 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2218 } 2219 } 2220 } 2221 2222 *failed_ = true; 2223 } 2224 } 2225 } 2226 } 2227 2228 private: 2229 Heap* const heap_; 2230 bool* const failed_; 2231}; 2232 2233class VerifyLiveStackReferences { 2234 public: 2235 explicit VerifyLiveStackReferences(Heap* heap) 2236 : heap_(heap), 2237 failed_(false) {} 2238 2239 void operator()(mirror::Object* obj) const 2240 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2241 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2242 obj->VisitReferences<true>(visitor); 2243 } 2244 2245 bool Failed() const { 2246 return failed_; 2247 } 2248 2249 private: 2250 Heap* const heap_; 2251 bool failed_; 2252}; 2253 2254bool Heap::VerifyMissingCardMarks() { 2255 Thread* self = Thread::Current(); 2256 Locks::mutator_lock_->AssertExclusiveHeld(self); 2257 2258 // We need to sort the live stack since we binary search it. 2259 live_stack_->Sort(); 2260 // Since we sorted the allocation stack content, need to revoke all 2261 // thread-local allocation stacks. 2262 RevokeAllThreadLocalAllocationStacks(self); 2263 VerifyLiveStackReferences visitor(this); 2264 GetLiveBitmap()->Visit(visitor); 2265 2266 // We can verify objects in the live stack since none of these should reference dead objects. 2267 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2268 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2269 visitor(*it); 2270 } 2271 } 2272 2273 if (visitor.Failed()) { 2274 DumpSpaces(); 2275 return false; 2276 } 2277 return true; 2278} 2279 2280void Heap::SwapStacks(Thread* self) { 2281 if (kUseThreadLocalAllocationStack) { 2282 live_stack_->AssertAllZero(); 2283 } 2284 allocation_stack_.swap(live_stack_); 2285} 2286 2287void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2288 // This must be called only during the pause. 2289 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2290 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2291 MutexLock mu2(self, *Locks::thread_list_lock_); 2292 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2293 for (Thread* t : thread_list) { 2294 t->RevokeThreadLocalAllocationStack(); 2295 } 2296} 2297 2298void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2299 if (kIsDebugBuild) { 2300 if (bump_pointer_space_ != nullptr) { 2301 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2302 } 2303 } 2304} 2305 2306accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2307 auto it = mod_union_tables_.find(space); 2308 if (it == mod_union_tables_.end()) { 2309 return nullptr; 2310 } 2311 return it->second; 2312} 2313 2314accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2315 auto it = remembered_sets_.find(space); 2316 if (it == remembered_sets_.end()) { 2317 return nullptr; 2318 } 2319 return it->second; 2320} 2321 2322void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2323 // Clear cards and keep track of cards cleared in the mod-union table. 2324 for (const auto& space : continuous_spaces_) { 2325 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2326 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2327 if (table != nullptr) { 2328 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2329 "ImageModUnionClearCards"; 2330 TimingLogger::ScopedSplit split(name, &timings); 2331 table->ClearCards(); 2332 } else if (use_rem_sets && rem_set != nullptr) { 2333 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2334 << static_cast<int>(collector_type_); 2335 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2336 rem_set->ClearCards(); 2337 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2338 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2339 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2340 // were dirty before the GC started. 2341 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2342 // -> clean(cleaning thread). 2343 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2344 // roots and then we scan / update mod union tables after. We will always scan either card. 2345 // If we end up with the non aged card, we scan it it in the pause. 2346 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2347 } 2348 } 2349} 2350 2351static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2352} 2353 2354void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2355 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2356 Thread* self = Thread::Current(); 2357 2358 if (verify_pre_gc_heap_) { 2359 thread_list->SuspendAll(); 2360 { 2361 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2362 if (!VerifyHeapReferences()) { 2363 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2364 } 2365 } 2366 thread_list->ResumeAll(); 2367 } 2368 2369 // Check that all objects which reference things in the live stack are on dirty cards. 2370 if (verify_missing_card_marks_) { 2371 thread_list->SuspendAll(); 2372 { 2373 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2374 SwapStacks(self); 2375 // Sort the live stack so that we can quickly binary search it later. 2376 if (!VerifyMissingCardMarks()) { 2377 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2378 } 2379 SwapStacks(self); 2380 } 2381 thread_list->ResumeAll(); 2382 } 2383 2384 if (verify_mod_union_table_) { 2385 thread_list->SuspendAll(); 2386 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2387 for (const auto& table_pair : mod_union_tables_) { 2388 accounting::ModUnionTable* mod_union_table = table_pair.second; 2389 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2390 mod_union_table->Verify(); 2391 } 2392 thread_list->ResumeAll(); 2393 } 2394} 2395 2396void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2397 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2398 // reachable objects. 2399 if (verify_post_gc_heap_) { 2400 Thread* self = Thread::Current(); 2401 CHECK_NE(self->GetState(), kRunnable); 2402 { 2403 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2404 // Swapping bound bitmaps does nothing. 2405 gc->SwapBitmaps(); 2406 SwapSemiSpaces(); 2407 if (!VerifyHeapReferences()) { 2408 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2409 } 2410 SwapSemiSpaces(); 2411 gc->SwapBitmaps(); 2412 } 2413 } 2414} 2415 2416void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2417 if (verify_system_weaks_) { 2418 Thread* self = Thread::Current(); 2419 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2420 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2421 mark_sweep->VerifySystemWeaks(); 2422 } 2423} 2424 2425void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2426 if (verify_pre_gc_rosalloc_) { 2427 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2428 for (const auto& space : continuous_spaces_) { 2429 if (space->IsRosAllocSpace()) { 2430 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2431 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2432 rosalloc_space->Verify(); 2433 } 2434 } 2435 } 2436} 2437 2438void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2439 if (verify_post_gc_rosalloc_) { 2440 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2441 for (const auto& space : continuous_spaces_) { 2442 if (space->IsRosAllocSpace()) { 2443 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2444 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2445 rosalloc_space->Verify(); 2446 } 2447 } 2448 } 2449} 2450 2451collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2452 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2453 MutexLock mu(self, *gc_complete_lock_); 2454 return WaitForGcToCompleteLocked(self); 2455} 2456 2457collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2458 collector::GcType last_gc_type = collector::kGcTypeNone; 2459 uint64_t wait_start = NanoTime(); 2460 while (collector_type_running_ != kCollectorTypeNone) { 2461 ATRACE_BEGIN("GC: Wait For Completion"); 2462 // We must wait, change thread state then sleep on gc_complete_cond_; 2463 gc_complete_cond_->Wait(self); 2464 last_gc_type = last_gc_type_; 2465 ATRACE_END(); 2466 } 2467 uint64_t wait_time = NanoTime() - wait_start; 2468 total_wait_time_ += wait_time; 2469 if (wait_time > long_pause_log_threshold_) { 2470 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2471 } 2472 return last_gc_type; 2473} 2474 2475void Heap::DumpForSigQuit(std::ostream& os) { 2476 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2477 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2478 DumpGcPerformanceInfo(os); 2479} 2480 2481size_t Heap::GetPercentFree() { 2482 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2483} 2484 2485void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2486 if (max_allowed_footprint > GetMaxMemory()) { 2487 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2488 << PrettySize(GetMaxMemory()); 2489 max_allowed_footprint = GetMaxMemory(); 2490 } 2491 max_allowed_footprint_ = max_allowed_footprint; 2492} 2493 2494bool Heap::IsMovableObject(const mirror::Object* obj) const { 2495 if (kMovingCollector) { 2496 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2497 if (space != nullptr) { 2498 // TODO: Check large object? 2499 return space->CanMoveObjects(); 2500 } 2501 } 2502 return false; 2503} 2504 2505void Heap::UpdateMaxNativeFootprint() { 2506 size_t native_size = native_bytes_allocated_; 2507 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2508 size_t target_size = native_size / GetTargetHeapUtilization(); 2509 if (target_size > native_size + max_free_) { 2510 target_size = native_size + max_free_; 2511 } else if (target_size < native_size + min_free_) { 2512 target_size = native_size + min_free_; 2513 } 2514 native_footprint_gc_watermark_ = target_size; 2515 native_footprint_limit_ = 2 * target_size - native_size; 2516} 2517 2518collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2519 for (const auto& collector : garbage_collectors_) { 2520 if (collector->GetCollectorType() == collector_type_ && 2521 collector->GetGcType() == gc_type) { 2522 return collector; 2523 } 2524 } 2525 return nullptr; 2526} 2527 2528void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2529 // We know what our utilization is at this moment. 2530 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2531 const size_t bytes_allocated = GetBytesAllocated(); 2532 last_gc_size_ = bytes_allocated; 2533 last_gc_time_ns_ = NanoTime(); 2534 size_t target_size; 2535 collector::GcType gc_type = collector_ran->GetGcType(); 2536 if (gc_type != collector::kGcTypeSticky) { 2537 // Grow the heap for non sticky GC. 2538 target_size = bytes_allocated / GetTargetHeapUtilization(); 2539 if (target_size > bytes_allocated + max_free_) { 2540 target_size = bytes_allocated + max_free_; 2541 } else if (target_size < bytes_allocated + min_free_) { 2542 target_size = bytes_allocated + min_free_; 2543 } 2544 native_need_to_run_finalization_ = true; 2545 next_gc_type_ = collector::kGcTypeSticky; 2546 } else { 2547 collector::GcType non_sticky_gc_type = 2548 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2549 // Find what the next non sticky collector will be. 2550 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2551 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2552 // do another sticky collection next. 2553 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2554 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2555 // if the sticky GC throughput always remained >= the full/partial throughput. 2556 if (collector_ran->GetEstimatedLastIterationThroughput() * kStickyGcThroughputAdjustment >= 2557 non_sticky_collector->GetEstimatedMeanThroughput() && 2558 non_sticky_collector->GetIterations() > 0 && 2559 bytes_allocated <= max_allowed_footprint_) { 2560 next_gc_type_ = collector::kGcTypeSticky; 2561 } else { 2562 next_gc_type_ = non_sticky_gc_type; 2563 } 2564 // If we have freed enough memory, shrink the heap back down. 2565 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2566 target_size = bytes_allocated + max_free_; 2567 } else { 2568 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2569 } 2570 } 2571 if (!ignore_max_footprint_) { 2572 SetIdealFootprint(target_size); 2573 if (IsGcConcurrent()) { 2574 // Calculate when to perform the next ConcurrentGC. 2575 // Calculate the estimated GC duration. 2576 const double gc_duration_seconds = NsToMs(collector_ran->GetDurationNs()) / 1000.0; 2577 // Estimate how many remaining bytes we will have when we need to start the next GC. 2578 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2579 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2580 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2581 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2582 // A never going to happen situation that from the estimated allocation rate we will exceed 2583 // the applications entire footprint with the given estimated allocation rate. Schedule 2584 // another GC nearly straight away. 2585 remaining_bytes = kMinConcurrentRemainingBytes; 2586 } 2587 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2588 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2589 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2590 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2591 // right away. 2592 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2593 } 2594 } 2595} 2596 2597void Heap::ClearGrowthLimit() { 2598 growth_limit_ = capacity_; 2599 non_moving_space_->ClearGrowthLimit(); 2600} 2601 2602void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2603 ScopedObjectAccess soa(self); 2604 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(object)); 2605 jvalue args[1]; 2606 args[0].l = arg.get(); 2607 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2608} 2609 2610void Heap::EnqueueClearedReferences() { 2611 Thread* self = Thread::Current(); 2612 Locks::mutator_lock_->AssertNotHeld(self); 2613 if (!cleared_references_.IsEmpty()) { 2614 // When a runtime isn't started there are no reference queues to care about so ignore. 2615 if (LIKELY(Runtime::Current()->IsStarted())) { 2616 ScopedObjectAccess soa(self); 2617 ScopedLocalRef<jobject> arg(self->GetJniEnv(), 2618 soa.AddLocalReference<jobject>(cleared_references_.GetList())); 2619 jvalue args[1]; 2620 args[0].l = arg.get(); 2621 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_ReferenceQueue_add, args); 2622 } 2623 cleared_references_.Clear(); 2624 } 2625} 2626 2627void Heap::RequestConcurrentGC(Thread* self) { 2628 // Make sure that we can do a concurrent GC. 2629 Runtime* runtime = Runtime::Current(); 2630 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2631 self->IsHandlingStackOverflow()) { 2632 return; 2633 } 2634 // We already have a request pending, no reason to start more until we update 2635 // concurrent_start_bytes_. 2636 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2637 JNIEnv* env = self->GetJniEnv(); 2638 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2639 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2640 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2641 WellKnownClasses::java_lang_Daemons_requestGC); 2642 CHECK(!env->ExceptionCheck()); 2643} 2644 2645void Heap::ConcurrentGC(Thread* self) { 2646 if (Runtime::Current()->IsShuttingDown(self)) { 2647 return; 2648 } 2649 // Wait for any GCs currently running to finish. 2650 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2651 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2652 // instead. E.g. can't do partial, so do full instead. 2653 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2654 collector::kGcTypeNone) { 2655 for (collector::GcType gc_type : gc_plan_) { 2656 // Attempt to run the collector, if we succeed, we are done. 2657 if (gc_type > next_gc_type_ && 2658 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2659 break; 2660 } 2661 } 2662 } 2663 } 2664} 2665 2666void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2667 Thread* self = Thread::Current(); 2668 { 2669 MutexLock mu(self, *heap_trim_request_lock_); 2670 if (desired_collector_type_ == desired_collector_type) { 2671 return; 2672 } 2673 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2674 desired_collector_type_ = desired_collector_type; 2675 } 2676 SignalHeapTrimDaemon(self); 2677} 2678 2679void Heap::RequestHeapTrim() { 2680 // Request a heap trim only if we do not currently care about pause times. 2681 if (CareAboutPauseTimes()) { 2682 return; 2683 } 2684 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2685 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2686 // a space it will hold its lock and can become a cause of jank. 2687 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2688 // forking. 2689 2690 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2691 // because that only marks object heads, so a large array looks like lots of empty space. We 2692 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2693 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2694 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2695 // not how much use we're making of those pages. 2696 2697 Thread* self = Thread::Current(); 2698 Runtime* runtime = Runtime::Current(); 2699 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2700 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2701 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2702 // as we don't hold the lock while requesting the trim). 2703 return; 2704 } 2705 { 2706 MutexLock mu(self, *heap_trim_request_lock_); 2707 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2708 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2709 // just yet. 2710 return; 2711 } 2712 heap_trim_request_pending_ = true; 2713 } 2714 // Notify the daemon thread which will actually do the heap trim. 2715 SignalHeapTrimDaemon(self); 2716} 2717 2718void Heap::SignalHeapTrimDaemon(Thread* self) { 2719 JNIEnv* env = self->GetJniEnv(); 2720 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2721 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2722 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2723 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2724 CHECK(!env->ExceptionCheck()); 2725} 2726 2727void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2728 if (rosalloc_space_ != nullptr) { 2729 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2730 } 2731 if (bump_pointer_space_ != nullptr) { 2732 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2733 } 2734} 2735 2736void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2737 if (rosalloc_space_ != nullptr) { 2738 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2739 } 2740} 2741 2742void Heap::RevokeAllThreadLocalBuffers() { 2743 if (rosalloc_space_ != nullptr) { 2744 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2745 } 2746 if (bump_pointer_space_ != nullptr) { 2747 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2748 } 2749} 2750 2751bool Heap::IsGCRequestPending() const { 2752 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2753} 2754 2755void Heap::RunFinalization(JNIEnv* env) { 2756 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2757 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2758 CHECK(WellKnownClasses::java_lang_System != nullptr); 2759 WellKnownClasses::java_lang_System_runFinalization = 2760 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2761 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2762 } 2763 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2764 WellKnownClasses::java_lang_System_runFinalization); 2765} 2766 2767void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2768 Thread* self = ThreadForEnv(env); 2769 if (native_need_to_run_finalization_) { 2770 RunFinalization(env); 2771 UpdateMaxNativeFootprint(); 2772 native_need_to_run_finalization_ = false; 2773 } 2774 // Total number of native bytes allocated. 2775 native_bytes_allocated_.FetchAndAdd(bytes); 2776 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2777 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2778 collector::kGcTypeFull; 2779 2780 // The second watermark is higher than the gc watermark. If you hit this it means you are 2781 // allocating native objects faster than the GC can keep up with. 2782 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2783 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2784 // Just finished a GC, attempt to run finalizers. 2785 RunFinalization(env); 2786 CHECK(!env->ExceptionCheck()); 2787 } 2788 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2789 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2790 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2791 RunFinalization(env); 2792 native_need_to_run_finalization_ = false; 2793 CHECK(!env->ExceptionCheck()); 2794 } 2795 // We have just run finalizers, update the native watermark since it is very likely that 2796 // finalizers released native managed allocations. 2797 UpdateMaxNativeFootprint(); 2798 } else if (!IsGCRequestPending()) { 2799 if (IsGcConcurrent()) { 2800 RequestConcurrentGC(self); 2801 } else { 2802 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2803 } 2804 } 2805 } 2806} 2807 2808void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2809 int expected_size, new_size; 2810 do { 2811 expected_size = native_bytes_allocated_.Load(); 2812 new_size = expected_size - bytes; 2813 if (UNLIKELY(new_size < 0)) { 2814 ScopedObjectAccess soa(env); 2815 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2816 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2817 "registered as allocated", bytes, expected_size).c_str()); 2818 break; 2819 } 2820 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2821} 2822 2823size_t Heap::GetTotalMemory() const { 2824 size_t ret = 0; 2825 for (const auto& space : continuous_spaces_) { 2826 // Currently don't include the image space. 2827 if (!space->IsImageSpace()) { 2828 ret += space->Size(); 2829 } 2830 } 2831 for (const auto& space : discontinuous_spaces_) { 2832 if (space->IsLargeObjectSpace()) { 2833 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2834 } 2835 } 2836 return ret; 2837} 2838 2839void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2840 DCHECK(mod_union_table != nullptr); 2841 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2842} 2843 2844void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2845 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2846 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2847 strlen(ClassHelper(c).GetDescriptor()) == 0); 2848 CHECK_GE(byte_count, sizeof(mirror::Object)); 2849} 2850 2851void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2852 CHECK(remembered_set != nullptr); 2853 space::Space* space = remembered_set->GetSpace(); 2854 CHECK(space != nullptr); 2855 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2856 remembered_sets_.Put(space, remembered_set); 2857 CHECK(remembered_sets_.find(space) != remembered_sets_.end()); 2858} 2859 2860void Heap::RemoveRememberedSet(space::Space* space) { 2861 CHECK(space != nullptr); 2862 auto it = remembered_sets_.find(space); 2863 CHECK(it != remembered_sets_.end()); 2864 remembered_sets_.erase(it); 2865 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2866} 2867 2868void Heap::ClearMarkedObjects() { 2869 // Clear all of the spaces' mark bitmaps. 2870 for (const auto& space : GetContinuousSpaces()) { 2871 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2872 if (space->GetLiveBitmap() != mark_bitmap) { 2873 mark_bitmap->Clear(); 2874 } 2875 } 2876 // Clear the marked objects in the discontinous space object sets. 2877 for (const auto& space : GetDiscontinuousSpaces()) { 2878 space->GetMarkObjects()->Clear(); 2879 } 2880} 2881 2882} // namespace gc 2883} // namespace art 2884