heap.cc revision 31f441464c0c8f840aba37e236ad133f30308d70
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_->SetGrowthLimit(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 if (iterations != 0) { 683 os << ConstDumpable<CumulativeLogger>(logger); 684 const uint64_t total_ns = logger.GetTotalNs(); 685 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 686 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 687 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 688 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 689 Histogram<uint64_t>::CumulativeData cumulative_data; 690 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 691 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 692 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 693 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 694 << collector->GetName() << " freed: " << freed_objects 695 << " objects with total size " << PrettySize(freed_bytes) << "\n" 696 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 697 << PrettySize(freed_bytes / seconds) << "/s\n"; 698 total_duration += total_ns; 699 total_paused_time += total_pause_ns; 700 } 701 collector->ResetMeasurements(); 702 } 703 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 704 if (total_duration != 0) { 705 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 706 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 707 os << "Mean GC size throughput: " 708 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 709 os << "Mean GC object throughput: " 710 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 711 } 712 size_t total_objects_allocated = GetObjectsAllocatedEver(); 713 os << "Total number of allocations: " << total_objects_allocated << "\n"; 714 size_t total_bytes_allocated = GetBytesAllocatedEver(); 715 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 716 if (kMeasureAllocationTime) { 717 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 718 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 719 << "\n"; 720 } 721 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 722 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 723 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 724} 725 726Heap::~Heap() { 727 VLOG(heap) << "Starting ~Heap()"; 728 STLDeleteElements(&garbage_collectors_); 729 // If we don't reset then the mark stack complains in its destructor. 730 allocation_stack_->Reset(); 731 live_stack_->Reset(); 732 STLDeleteValues(&mod_union_tables_); 733 STLDeleteValues(&remembered_sets_); 734 STLDeleteElements(&continuous_spaces_); 735 STLDeleteElements(&discontinuous_spaces_); 736 delete gc_complete_lock_; 737 delete heap_trim_request_lock_; 738 VLOG(heap) << "Finished ~Heap()"; 739} 740 741space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 742 bool fail_ok) const { 743 for (const auto& space : continuous_spaces_) { 744 if (space->Contains(obj)) { 745 return space; 746 } 747 } 748 if (!fail_ok) { 749 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 750 } 751 return NULL; 752} 753 754space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 755 bool fail_ok) const { 756 for (const auto& space : discontinuous_spaces_) { 757 if (space->Contains(obj)) { 758 return space; 759 } 760 } 761 if (!fail_ok) { 762 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 763 } 764 return NULL; 765} 766 767space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 768 space::Space* result = FindContinuousSpaceFromObject(obj, true); 769 if (result != NULL) { 770 return result; 771 } 772 return FindDiscontinuousSpaceFromObject(obj, true); 773} 774 775struct SoftReferenceArgs { 776 IsMarkedCallback* is_marked_callback_; 777 MarkObjectCallback* mark_callback_; 778 void* arg_; 779}; 780 781mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 782 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 783 // TODO: Not preserve all soft references. 784 return args->mark_callback_(obj, args->arg_); 785} 786 787void Heap::ProcessSoftReferences(TimingLogger& timings, bool clear_soft, 788 IsMarkedCallback* is_marked_callback, 789 MarkObjectCallback* mark_object_callback, 790 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 791 // Unless required to clear soft references with white references, preserve some white referents. 792 if (!clear_soft) { 793 // Don't clear for sticky GC. 794 SoftReferenceArgs soft_reference_args; 795 soft_reference_args.is_marked_callback_ = is_marked_callback; 796 soft_reference_args.mark_callback_ = mark_object_callback; 797 soft_reference_args.arg_ = arg; 798 // References with a marked referent are removed from the list. 799 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 800 &soft_reference_args); 801 process_mark_stack_callback(arg); 802 } 803} 804 805// Process reference class instances and schedule finalizations. 806void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 807 IsMarkedCallback* is_marked_callback, 808 MarkObjectCallback* mark_object_callback, 809 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 810 timings.StartSplit("(Paused)ProcessReferences"); 811 ProcessSoftReferences(timings, clear_soft, is_marked_callback, mark_object_callback, 812 process_mark_stack_callback, arg); 813 // Clear all remaining soft and weak references with white referents. 814 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 815 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 816 timings.EndSplit(); 817 // Preserve all white objects with finalize methods and schedule them for finalization. 818 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 819 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 820 mark_object_callback, arg); 821 process_mark_stack_callback(arg); 822 timings.EndSplit(); 823 timings.StartSplit("(Paused)ProcessReferences"); 824 // Clear all f-reachable soft and weak references with white referents. 825 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 826 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 827 // Clear all phantom references with white referents. 828 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 829 // At this point all reference queues other than the cleared references should be empty. 830 DCHECK(soft_reference_queue_.IsEmpty()); 831 DCHECK(weak_reference_queue_.IsEmpty()); 832 DCHECK(finalizer_reference_queue_.IsEmpty()); 833 DCHECK(phantom_reference_queue_.IsEmpty()); 834 timings.EndSplit(); 835} 836 837// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 838// marked, put it on the appropriate list in the heap for later processing. 839void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Reference* ref, 840 IsMarkedCallback is_marked_callback, void* arg) { 841 // klass can be the class of the old object if the visitor already updated the class of ref. 842 DCHECK(klass->IsReferenceClass()); 843 mirror::Object* referent = ref->GetReferent(); 844 if (referent != nullptr) { 845 mirror::Object* forward_address = is_marked_callback(referent, arg); 846 // Null means that the object is not currently marked. 847 if (forward_address == nullptr) { 848 Thread* self = Thread::Current(); 849 // TODO: Remove these locks, and use atomic stacks for storing references? 850 // We need to check that the references haven't already been enqueued since we can end up 851 // scanning the same reference multiple times due to dirty cards. 852 if (klass->IsSoftReferenceClass()) { 853 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 854 } else if (klass->IsWeakReferenceClass()) { 855 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 856 } else if (klass->IsFinalizerReferenceClass()) { 857 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 858 } else if (klass->IsPhantomReferenceClass()) { 859 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 860 } else { 861 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 862 << klass->GetAccessFlags(); 863 } 864 } else if (referent != forward_address) { 865 // Referent is already marked and we need to update it. 866 ref->SetReferent<false>(forward_address); 867 } 868 } 869} 870 871space::ImageSpace* Heap::GetImageSpace() const { 872 for (const auto& space : continuous_spaces_) { 873 if (space->IsImageSpace()) { 874 return space->AsImageSpace(); 875 } 876 } 877 return NULL; 878} 879 880static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 881 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 882 if (used_bytes < chunk_size) { 883 size_t chunk_free_bytes = chunk_size - used_bytes; 884 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 885 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 886 } 887} 888 889void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 890 std::ostringstream oss; 891 size_t total_bytes_free = GetFreeMemory(); 892 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 893 << " free bytes"; 894 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 895 if (!large_object_allocation && total_bytes_free >= byte_count) { 896 size_t max_contiguous_allocation = 0; 897 for (const auto& space : continuous_spaces_) { 898 if (space->IsMallocSpace()) { 899 // To allow the Walk/InspectAll() to exclusively-lock the mutator 900 // lock, temporarily release the shared access to the mutator 901 // lock here by transitioning to the suspended state. 902 Locks::mutator_lock_->AssertSharedHeld(self); 903 self->TransitionFromRunnableToSuspended(kSuspended); 904 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 905 self->TransitionFromSuspendedToRunnable(); 906 Locks::mutator_lock_->AssertSharedHeld(self); 907 } 908 } 909 oss << "; failed due to fragmentation (largest possible contiguous allocation " 910 << max_contiguous_allocation << " bytes)"; 911 } 912 self->ThrowOutOfMemoryError(oss.str().c_str()); 913} 914 915void Heap::DoPendingTransitionOrTrim() { 916 Thread* self = Thread::Current(); 917 CollectorType desired_collector_type; 918 // Wait until we reach the desired transition time. 919 while (true) { 920 uint64_t wait_time; 921 { 922 MutexLock mu(self, *heap_trim_request_lock_); 923 desired_collector_type = desired_collector_type_; 924 uint64_t current_time = NanoTime(); 925 if (current_time >= heap_transition_target_time_) { 926 break; 927 } 928 wait_time = heap_transition_target_time_ - current_time; 929 } 930 ScopedThreadStateChange tsc(self, kSleeping); 931 usleep(wait_time / 1000); // Usleep takes microseconds. 932 } 933 // Transition the collector if the desired collector type is not the same as the current 934 // collector type. 935 TransitionCollector(desired_collector_type); 936 if (!CareAboutPauseTimes()) { 937 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 938 // about pauses. 939 Runtime* runtime = Runtime::Current(); 940 runtime->GetThreadList()->SuspendAll(); 941 runtime->GetMonitorList()->DeflateMonitors(); 942 runtime->GetThreadList()->ResumeAll(); 943 // Do a heap trim if it is needed. 944 Trim(); 945 } 946} 947 948void Heap::Trim() { 949 Thread* self = Thread::Current(); 950 { 951 MutexLock mu(self, *heap_trim_request_lock_); 952 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 953 return; 954 } 955 last_trim_time_ = NanoTime(); 956 heap_trim_request_pending_ = false; 957 } 958 { 959 // Need to do this before acquiring the locks since we don't want to get suspended while 960 // holding any locks. 961 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 962 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 963 // trimming. 964 MutexLock mu(self, *gc_complete_lock_); 965 // Ensure there is only one GC at a time. 966 WaitForGcToCompleteLocked(self); 967 collector_type_running_ = kCollectorTypeHeapTrim; 968 } 969 uint64_t start_ns = NanoTime(); 970 // Trim the managed spaces. 971 uint64_t total_alloc_space_allocated = 0; 972 uint64_t total_alloc_space_size = 0; 973 uint64_t managed_reclaimed = 0; 974 for (const auto& space : continuous_spaces_) { 975 if (space->IsMallocSpace()) { 976 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 977 total_alloc_space_size += alloc_space->Size(); 978 managed_reclaimed += alloc_space->Trim(); 979 } 980 } 981 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 982 if (bump_pointer_space_ != nullptr) { 983 total_alloc_space_allocated -= bump_pointer_space_->Size(); 984 } 985 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 986 static_cast<float>(total_alloc_space_size); 987 uint64_t gc_heap_end_ns = NanoTime(); 988 // We never move things in the native heap, so we can finish the GC at this point. 989 FinishGC(self, collector::kGcTypeNone); 990 // Trim the native heap. 991 dlmalloc_trim(0); 992 size_t native_reclaimed = 0; 993 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 994 uint64_t end_ns = NanoTime(); 995 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 996 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 997 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 998 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 999 << "%."; 1000} 1001 1002bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1003 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1004 // taking the lock. 1005 if (obj == nullptr) { 1006 return true; 1007 } 1008 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1009} 1010 1011bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1012 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1013} 1014 1015bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1016 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1017 return false; 1018 } 1019 for (const auto& space : continuous_spaces_) { 1020 if (space->HasAddress(obj)) { 1021 return true; 1022 } 1023 } 1024 return false; 1025} 1026 1027bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1028 bool search_live_stack, bool sorted) { 1029 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1030 return false; 1031 } 1032 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1033 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1034 if (obj == klass) { 1035 // This case happens for java.lang.Class. 1036 return true; 1037 } 1038 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1039 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1040 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1041 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1042 return temp_space_->Contains(obj); 1043 } 1044 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1045 space::DiscontinuousSpace* d_space = NULL; 1046 if (c_space != nullptr) { 1047 if (c_space->GetLiveBitmap()->Test(obj)) { 1048 return true; 1049 } 1050 } else { 1051 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1052 if (d_space != nullptr) { 1053 if (d_space->GetLiveObjects()->Test(obj)) { 1054 return true; 1055 } 1056 } 1057 } 1058 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1059 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1060 if (i > 0) { 1061 NanoSleep(MsToNs(10)); 1062 } 1063 if (search_allocation_stack) { 1064 if (sorted) { 1065 if (allocation_stack_->ContainsSorted(obj)) { 1066 return true; 1067 } 1068 } else if (allocation_stack_->Contains(obj)) { 1069 return true; 1070 } 1071 } 1072 1073 if (search_live_stack) { 1074 if (sorted) { 1075 if (live_stack_->ContainsSorted(obj)) { 1076 return true; 1077 } 1078 } else if (live_stack_->Contains(obj)) { 1079 return true; 1080 } 1081 } 1082 } 1083 // We need to check the bitmaps again since there is a race where we mark something as live and 1084 // then clear the stack containing it. 1085 if (c_space != nullptr) { 1086 if (c_space->GetLiveBitmap()->Test(obj)) { 1087 return true; 1088 } 1089 } else { 1090 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1091 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 1092 return true; 1093 } 1094 } 1095 return false; 1096} 1097 1098void Heap::DumpSpaces(std::ostream& stream) { 1099 for (const auto& space : continuous_spaces_) { 1100 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1101 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1102 stream << space << " " << *space << "\n"; 1103 if (live_bitmap != nullptr) { 1104 stream << live_bitmap << " " << *live_bitmap << "\n"; 1105 } 1106 if (mark_bitmap != nullptr) { 1107 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1108 } 1109 } 1110 for (const auto& space : discontinuous_spaces_) { 1111 stream << space << " " << *space << "\n"; 1112 } 1113} 1114 1115void Heap::VerifyObjectBody(mirror::Object* obj) { 1116 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1117 return; 1118 } 1119 // Ignore early dawn of the universe verifications. 1120 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 1121 return; 1122 } 1123 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1124 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 1125 mirror::Object::ClassOffset(), false); 1126 CHECK(c != nullptr) << "Null class in object " << obj; 1127 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1128 CHECK(VerifyClassClass(c)); 1129 1130 if (verify_object_mode_ > kVerifyObjectModeFast) { 1131 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1132 if (!IsLiveObjectLocked(obj)) { 1133 DumpSpaces(); 1134 LOG(FATAL) << "Object is dead: " << obj; 1135 } 1136 } 1137} 1138 1139void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1140 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1141} 1142 1143void Heap::VerifyHeap() { 1144 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1145 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1146} 1147 1148void Heap::RecordFree(ssize_t freed_objects, ssize_t freed_bytes) { 1149 // Use signed comparison since freed bytes can be negative when background compaction foreground 1150 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1151 // free list backed space typically increasing memory footprint due to padding and binning. 1152 DCHECK_LE(freed_bytes, static_cast<ssize_t>(num_bytes_allocated_.Load())); 1153 DCHECK_GE(freed_objects, 0); 1154 num_bytes_allocated_.FetchAndSub(freed_bytes); 1155 if (Runtime::Current()->HasStatsEnabled()) { 1156 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1157 thread_stats->freed_objects += freed_objects; 1158 thread_stats->freed_bytes += freed_bytes; 1159 // TODO: Do this concurrently. 1160 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1161 global_stats->freed_objects += freed_objects; 1162 global_stats->freed_bytes += freed_bytes; 1163 } 1164} 1165 1166mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1167 size_t alloc_size, size_t* bytes_allocated, 1168 size_t* usable_size, 1169 mirror::Class** klass) { 1170 mirror::Object* ptr = nullptr; 1171 bool was_default_allocator = allocator == GetCurrentAllocator(); 1172 DCHECK(klass != nullptr); 1173 SirtRef<mirror::Class> sirt_klass(self, *klass); 1174 // The allocation failed. If the GC is running, block until it completes, and then retry the 1175 // allocation. 1176 collector::GcType last_gc = WaitForGcToComplete(self); 1177 if (last_gc != collector::kGcTypeNone) { 1178 // If we were the default allocator but the allocator changed while we were suspended, 1179 // abort the allocation. 1180 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1181 *klass = sirt_klass.get(); 1182 return nullptr; 1183 } 1184 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1185 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1186 } 1187 1188 collector::GcType tried_type = next_gc_type_; 1189 if (ptr == nullptr) { 1190 const bool gc_ran = 1191 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1192 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1193 *klass = sirt_klass.get(); 1194 return nullptr; 1195 } 1196 if (gc_ran) { 1197 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1198 } 1199 } 1200 1201 // Loop through our different Gc types and try to Gc until we get enough free memory. 1202 for (collector::GcType gc_type : gc_plan_) { 1203 if (ptr != nullptr) { 1204 break; 1205 } 1206 if (gc_type == tried_type) { 1207 continue; 1208 } 1209 // Attempt to run the collector, if we succeed, re-try the allocation. 1210 const bool gc_ran = 1211 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1212 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1213 *klass = sirt_klass.get(); 1214 return nullptr; 1215 } 1216 if (gc_ran) { 1217 // Did we free sufficient memory for the allocation to succeed? 1218 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1219 } 1220 } 1221 // Allocations have failed after GCs; this is an exceptional state. 1222 if (ptr == nullptr) { 1223 // Try harder, growing the heap if necessary. 1224 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1225 } 1226 if (ptr == nullptr) { 1227 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1228 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1229 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1230 // OOME. 1231 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1232 << " allocation"; 1233 // TODO: Run finalization, but this may cause more allocations to occur. 1234 // We don't need a WaitForGcToComplete here either. 1235 DCHECK(!gc_plan_.empty()); 1236 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1237 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1238 *klass = sirt_klass.get(); 1239 return nullptr; 1240 } 1241 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1242 if (ptr == nullptr) { 1243 ThrowOutOfMemoryError(self, alloc_size, false); 1244 } 1245 } 1246 *klass = sirt_klass.get(); 1247 return ptr; 1248} 1249 1250void Heap::SetTargetHeapUtilization(float target) { 1251 DCHECK_GT(target, 0.0f); // asserted in Java code 1252 DCHECK_LT(target, 1.0f); 1253 target_utilization_ = target; 1254} 1255 1256size_t Heap::GetObjectsAllocated() const { 1257 size_t total = 0; 1258 for (space::AllocSpace* space : alloc_spaces_) { 1259 total += space->GetObjectsAllocated(); 1260 } 1261 return total; 1262} 1263 1264size_t Heap::GetObjectsAllocatedEver() const { 1265 return GetObjectsFreedEver() + GetObjectsAllocated(); 1266} 1267 1268size_t Heap::GetBytesAllocatedEver() const { 1269 return GetBytesFreedEver() + GetBytesAllocated(); 1270} 1271 1272class InstanceCounter { 1273 public: 1274 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1275 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1276 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1277 } 1278 static void Callback(mirror::Object* obj, void* arg) 1279 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1280 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1281 mirror::Class* instance_class = obj->GetClass(); 1282 CHECK(instance_class != nullptr); 1283 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1284 if (instance_counter->use_is_assignable_from_) { 1285 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1286 ++instance_counter->counts_[i]; 1287 } 1288 } else if (instance_class == instance_counter->classes_[i]) { 1289 ++instance_counter->counts_[i]; 1290 } 1291 } 1292 } 1293 1294 private: 1295 const std::vector<mirror::Class*>& classes_; 1296 bool use_is_assignable_from_; 1297 uint64_t* const counts_; 1298 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1299}; 1300 1301void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1302 uint64_t* counts) { 1303 // Can't do any GC in this function since this may move classes. 1304 Thread* self = Thread::Current(); 1305 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1306 InstanceCounter counter(classes, use_is_assignable_from, counts); 1307 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1308 VisitObjects(InstanceCounter::Callback, &counter); 1309 self->EndAssertNoThreadSuspension(old_cause); 1310} 1311 1312class InstanceCollector { 1313 public: 1314 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1315 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1316 : class_(c), max_count_(max_count), instances_(instances) { 1317 } 1318 static void Callback(mirror::Object* obj, void* arg) 1319 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1320 DCHECK(arg != nullptr); 1321 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1322 mirror::Class* instance_class = obj->GetClass(); 1323 if (instance_class == instance_collector->class_) { 1324 if (instance_collector->max_count_ == 0 || 1325 instance_collector->instances_.size() < instance_collector->max_count_) { 1326 instance_collector->instances_.push_back(obj); 1327 } 1328 } 1329 } 1330 1331 private: 1332 mirror::Class* class_; 1333 uint32_t max_count_; 1334 std::vector<mirror::Object*>& instances_; 1335 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1336}; 1337 1338void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1339 std::vector<mirror::Object*>& instances) { 1340 // Can't do any GC in this function since this may move classes. 1341 Thread* self = Thread::Current(); 1342 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1343 InstanceCollector collector(c, max_count, instances); 1344 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1345 VisitObjects(&InstanceCollector::Callback, &collector); 1346 self->EndAssertNoThreadSuspension(old_cause); 1347} 1348 1349class ReferringObjectsFinder { 1350 public: 1351 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1352 std::vector<mirror::Object*>& referring_objects) 1353 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1354 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1355 } 1356 1357 static void Callback(mirror::Object* obj, void* arg) 1358 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1359 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1360 } 1361 1362 // For bitmap Visit. 1363 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1364 // annotalysis on visitors. 1365 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1366 o->VisitReferences<true>(*this); 1367 } 1368 1369 // For Object::VisitReferences. 1370 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1371 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1372 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 1373 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1374 referring_objects_.push_back(obj); 1375 } 1376 } 1377 1378 private: 1379 mirror::Object* object_; 1380 uint32_t max_count_; 1381 std::vector<mirror::Object*>& referring_objects_; 1382 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1383}; 1384 1385void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1386 std::vector<mirror::Object*>& referring_objects) { 1387 // Can't do any GC in this function since this may move the object o. 1388 Thread* self = Thread::Current(); 1389 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1390 ReferringObjectsFinder finder(o, max_count, referring_objects); 1391 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1392 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1393 self->EndAssertNoThreadSuspension(old_cause); 1394} 1395 1396void Heap::CollectGarbage(bool clear_soft_references) { 1397 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1398 // last GC will not have necessarily been cleared. 1399 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1400} 1401 1402void Heap::TransitionCollector(CollectorType collector_type) { 1403 if (collector_type == collector_type_) { 1404 return; 1405 } 1406 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1407 << " -> " << static_cast<int>(collector_type); 1408 uint64_t start_time = NanoTime(); 1409 uint32_t before_size = GetTotalMemory(); 1410 uint32_t before_allocated = num_bytes_allocated_.Load(); 1411 ThreadList* tl = Runtime::Current()->GetThreadList(); 1412 Thread* self = Thread::Current(); 1413 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1414 Locks::mutator_lock_->AssertNotHeld(self); 1415 const bool copying_transition = 1416 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1417 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1418 // compacting_gc_disable_count_, this should rarely occurs). 1419 for (;;) { 1420 { 1421 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1422 MutexLock mu(self, *gc_complete_lock_); 1423 // Ensure there is only one GC at a time. 1424 WaitForGcToCompleteLocked(self); 1425 // If someone else beat us to it and changed the collector before we could, exit. 1426 // This is safe to do before the suspend all since we set the collector_type_running_ before 1427 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1428 // then it would get blocked on WaitForGcToCompleteLocked. 1429 if (collector_type == collector_type_) { 1430 return; 1431 } 1432 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1433 if (!copying_transition || disable_moving_gc_count_ == 0) { 1434 // TODO: Not hard code in semi-space collector? 1435 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1436 break; 1437 } 1438 } 1439 usleep(1000); 1440 } 1441 tl->SuspendAll(); 1442 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1443 switch (collector_type) { 1444 case kCollectorTypeSS: 1445 // Fall-through. 1446 case kCollectorTypeGSS: { 1447 if (!IsMovingGc(collector_type_)) { 1448 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1449 // pointer space last transition it will be protected. 1450 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1451 Compact(bump_pointer_space_, main_space_); 1452 } 1453 break; 1454 } 1455 case kCollectorTypeMS: 1456 // Fall through. 1457 case kCollectorTypeCMS: { 1458 if (IsMovingGc(collector_type_)) { 1459 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1460 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1461 Compact(main_space_, bump_pointer_space_); 1462 } 1463 break; 1464 } 1465 default: { 1466 LOG(FATAL) << "Attempted to transition to invalid collector type " 1467 << static_cast<size_t>(collector_type); 1468 break; 1469 } 1470 } 1471 ChangeCollector(collector_type); 1472 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1473 tl->ResumeAll(); 1474 // Can't call into java code with all threads suspended. 1475 EnqueueClearedReferences(); 1476 uint64_t duration = NanoTime() - start_time; 1477 GrowForUtilization(semi_space_collector_); 1478 FinishGC(self, collector::kGcTypeFull); 1479 int32_t after_size = GetTotalMemory(); 1480 int32_t delta_size = before_size - after_size; 1481 int32_t after_allocated = num_bytes_allocated_.Load(); 1482 int32_t delta_allocated = before_allocated - after_allocated; 1483 const std::string saved_bytes_str = 1484 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1485 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1486 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1487 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1488 << PrettySize(delta_size) << " saved"; 1489} 1490 1491void Heap::ChangeCollector(CollectorType collector_type) { 1492 // TODO: Only do this with all mutators suspended to avoid races. 1493 if (collector_type != collector_type_) { 1494 collector_type_ = collector_type; 1495 gc_plan_.clear(); 1496 switch (collector_type_) { 1497 case kCollectorTypeCC: // Fall-through. 1498 case kCollectorTypeSS: // Fall-through. 1499 case kCollectorTypeGSS: { 1500 gc_plan_.push_back(collector::kGcTypeFull); 1501 if (use_tlab_) { 1502 ChangeAllocator(kAllocatorTypeTLAB); 1503 } else { 1504 ChangeAllocator(kAllocatorTypeBumpPointer); 1505 } 1506 break; 1507 } 1508 case kCollectorTypeMS: { 1509 gc_plan_.push_back(collector::kGcTypeSticky); 1510 gc_plan_.push_back(collector::kGcTypePartial); 1511 gc_plan_.push_back(collector::kGcTypeFull); 1512 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1513 break; 1514 } 1515 case kCollectorTypeCMS: { 1516 gc_plan_.push_back(collector::kGcTypeSticky); 1517 gc_plan_.push_back(collector::kGcTypePartial); 1518 gc_plan_.push_back(collector::kGcTypeFull); 1519 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1520 break; 1521 } 1522 default: { 1523 LOG(FATAL) << "Unimplemented"; 1524 } 1525 } 1526 if (IsGcConcurrent()) { 1527 concurrent_start_bytes_ = 1528 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1529 } else { 1530 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1531 } 1532 } 1533} 1534 1535// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1536class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1537 public: 1538 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1539 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1540 } 1541 1542 void BuildBins(space::ContinuousSpace* space) { 1543 bin_live_bitmap_ = space->GetLiveBitmap(); 1544 bin_mark_bitmap_ = space->GetMarkBitmap(); 1545 BinContext context; 1546 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1547 context.collector_ = this; 1548 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1549 // Note: This requires traversing the space in increasing order of object addresses. 1550 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1551 // Add the last bin which spans after the last object to the end of the space. 1552 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1553 } 1554 1555 private: 1556 struct BinContext { 1557 uintptr_t prev_; // The end of the previous object. 1558 ZygoteCompactingCollector* collector_; 1559 }; 1560 // Maps from bin sizes to locations. 1561 std::multimap<size_t, uintptr_t> bins_; 1562 // Live bitmap of the space which contains the bins. 1563 accounting::SpaceBitmap* bin_live_bitmap_; 1564 // Mark bitmap of the space which contains the bins. 1565 accounting::SpaceBitmap* bin_mark_bitmap_; 1566 1567 static void Callback(mirror::Object* obj, void* arg) 1568 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1569 DCHECK(arg != nullptr); 1570 BinContext* context = reinterpret_cast<BinContext*>(arg); 1571 ZygoteCompactingCollector* collector = context->collector_; 1572 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1573 size_t bin_size = object_addr - context->prev_; 1574 // Add the bin consisting of the end of the previous object to the start of the current object. 1575 collector->AddBin(bin_size, context->prev_); 1576 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1577 } 1578 1579 void AddBin(size_t size, uintptr_t position) { 1580 if (size != 0) { 1581 bins_.insert(std::make_pair(size, position)); 1582 } 1583 } 1584 1585 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1586 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1587 // allocator. 1588 return false; 1589 } 1590 1591 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1592 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1593 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1594 mirror::Object* forward_address; 1595 // Find the smallest bin which we can move obj in. 1596 auto it = bins_.lower_bound(object_size); 1597 if (it == bins_.end()) { 1598 // No available space in the bins, place it in the target space instead (grows the zygote 1599 // space). 1600 size_t bytes_allocated; 1601 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1602 if (to_space_live_bitmap_ != nullptr) { 1603 to_space_live_bitmap_->Set(forward_address); 1604 } else { 1605 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1606 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1607 } 1608 } else { 1609 size_t size = it->first; 1610 uintptr_t pos = it->second; 1611 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1612 forward_address = reinterpret_cast<mirror::Object*>(pos); 1613 // Set the live and mark bits so that sweeping system weaks works properly. 1614 bin_live_bitmap_->Set(forward_address); 1615 bin_mark_bitmap_->Set(forward_address); 1616 DCHECK_GE(size, object_size); 1617 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1618 } 1619 // Copy the object over to its new location. 1620 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1621 if (kUseBakerOrBrooksReadBarrier) { 1622 obj->AssertReadBarrierPointer(); 1623 if (kUseBrooksReadBarrier) { 1624 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1625 forward_address->SetReadBarrierPointer(forward_address); 1626 } 1627 forward_address->AssertReadBarrierPointer(); 1628 } 1629 return forward_address; 1630 } 1631}; 1632 1633void Heap::UnBindBitmaps() { 1634 for (const auto& space : GetContinuousSpaces()) { 1635 if (space->IsContinuousMemMapAllocSpace()) { 1636 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1637 if (alloc_space->HasBoundBitmaps()) { 1638 alloc_space->UnBindBitmaps(); 1639 } 1640 } 1641 } 1642} 1643 1644void Heap::PreZygoteFork() { 1645 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1646 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1647 Thread* self = Thread::Current(); 1648 MutexLock mu(self, zygote_creation_lock_); 1649 // Try to see if we have any Zygote spaces. 1650 if (have_zygote_space_) { 1651 return; 1652 } 1653 VLOG(heap) << "Starting PreZygoteFork"; 1654 // Trim the pages at the end of the non moving space. 1655 non_moving_space_->Trim(); 1656 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1657 // there. 1658 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1659 // Change the collector to the post zygote one. 1660 if (kCompactZygote) { 1661 DCHECK(semi_space_collector_ != nullptr); 1662 // Temporarily disable rosalloc verification because the zygote 1663 // compaction will mess up the rosalloc internal metadata. 1664 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1665 ZygoteCompactingCollector zygote_collector(this); 1666 zygote_collector.BuildBins(non_moving_space_); 1667 // Create a new bump pointer space which we will compact into. 1668 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1669 non_moving_space_->Limit()); 1670 // Compact the bump pointer space to a new zygote bump pointer space. 1671 bool reset_main_space = false; 1672 if (IsMovingGc(collector_type_)) { 1673 zygote_collector.SetFromSpace(bump_pointer_space_); 1674 } else { 1675 CHECK(main_space_ != nullptr); 1676 // Copy from the main space. 1677 zygote_collector.SetFromSpace(main_space_); 1678 reset_main_space = true; 1679 } 1680 zygote_collector.SetToSpace(&target_space); 1681 1682 Runtime::Current()->GetThreadList()->SuspendAll(); 1683 zygote_collector.Run(kGcCauseCollectorTransition, false); 1684 if (IsMovingGc(collector_type_)) { 1685 SwapSemiSpaces(); 1686 } 1687 Runtime::Current()->GetThreadList()->ResumeAll(); 1688 1689 if (reset_main_space) { 1690 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1691 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1692 MemMap* mem_map = main_space_->ReleaseMemMap(); 1693 RemoveSpace(main_space_); 1694 delete main_space_; 1695 main_space_ = nullptr; 1696 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1697 AddSpace(main_space_); 1698 } else { 1699 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1700 } 1701 if (temp_space_ != nullptr) { 1702 CHECK(temp_space_->IsEmpty()); 1703 } 1704 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1705 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1706 // Update the end and write out image. 1707 non_moving_space_->SetEnd(target_space.End()); 1708 non_moving_space_->SetLimit(target_space.Limit()); 1709 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1710 } 1711 ChangeCollector(foreground_collector_type_); 1712 // Save the old space so that we can remove it after we complete creating the zygote space. 1713 space::MallocSpace* old_alloc_space = non_moving_space_; 1714 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1715 // the remaining available space. 1716 // Remove the old space before creating the zygote space since creating the zygote space sets 1717 // the old alloc space's bitmaps to nullptr. 1718 RemoveSpace(old_alloc_space); 1719 if (collector::SemiSpace::kUseRememberedSet) { 1720 // Sanity bound check. 1721 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1722 // Remove the remembered set for the now zygote space (the old 1723 // non-moving space). Note now that we have compacted objects into 1724 // the zygote space, the data in the remembered set is no longer 1725 // needed. The zygote space will instead have a mod-union table 1726 // from this point on. 1727 RemoveRememberedSet(old_alloc_space); 1728 } 1729 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1730 low_memory_mode_, 1731 &non_moving_space_); 1732 delete old_alloc_space; 1733 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1734 AddSpace(zygote_space, false); 1735 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1736 AddSpace(non_moving_space_); 1737 have_zygote_space_ = true; 1738 // Enable large object space allocations. 1739 large_object_threshold_ = kDefaultLargeObjectThreshold; 1740 // Create the zygote space mod union table. 1741 accounting::ModUnionTable* mod_union_table = 1742 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1743 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1744 AddModUnionTable(mod_union_table); 1745 if (collector::SemiSpace::kUseRememberedSet) { 1746 // Add a new remembered set for the post-zygote non-moving space. 1747 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1748 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1749 non_moving_space_); 1750 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1751 << "Failed to create post-zygote non-moving space remembered set"; 1752 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1753 } 1754} 1755 1756void Heap::FlushAllocStack() { 1757 MarkAllocStackAsLive(allocation_stack_.get()); 1758 allocation_stack_->Reset(); 1759} 1760 1761void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1762 accounting::SpaceBitmap* bitmap2, 1763 accounting::ObjectSet* large_objects, 1764 accounting::ObjectStack* stack) { 1765 DCHECK(bitmap1 != nullptr); 1766 DCHECK(bitmap2 != nullptr); 1767 mirror::Object** limit = stack->End(); 1768 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1769 const mirror::Object* obj = *it; 1770 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1771 if (bitmap1->HasAddress(obj)) { 1772 bitmap1->Set(obj); 1773 } else if (bitmap2->HasAddress(obj)) { 1774 bitmap2->Set(obj); 1775 } else { 1776 large_objects->Set(obj); 1777 } 1778 } 1779 } 1780} 1781 1782void Heap::SwapSemiSpaces() { 1783 CHECK(bump_pointer_space_ != nullptr); 1784 CHECK(temp_space_ != nullptr); 1785 std::swap(bump_pointer_space_, temp_space_); 1786} 1787 1788void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1789 space::ContinuousMemMapAllocSpace* source_space) { 1790 CHECK(kMovingCollector); 1791 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1792 if (target_space != source_space) { 1793 semi_space_collector_->SetFromSpace(source_space); 1794 semi_space_collector_->SetToSpace(target_space); 1795 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1796 } 1797} 1798 1799collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1800 bool clear_soft_references) { 1801 Thread* self = Thread::Current(); 1802 Runtime* runtime = Runtime::Current(); 1803 // If the heap can't run the GC, silently fail and return that no GC was run. 1804 switch (gc_type) { 1805 case collector::kGcTypePartial: { 1806 if (!have_zygote_space_) { 1807 return collector::kGcTypeNone; 1808 } 1809 break; 1810 } 1811 default: { 1812 // Other GC types don't have any special cases which makes them not runnable. The main case 1813 // here is full GC. 1814 } 1815 } 1816 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1817 Locks::mutator_lock_->AssertNotHeld(self); 1818 if (self->IsHandlingStackOverflow()) { 1819 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1820 } 1821 bool compacting_gc; 1822 { 1823 gc_complete_lock_->AssertNotHeld(self); 1824 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1825 MutexLock mu(self, *gc_complete_lock_); 1826 // Ensure there is only one GC at a time. 1827 WaitForGcToCompleteLocked(self); 1828 compacting_gc = IsMovingGc(collector_type_); 1829 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1830 if (compacting_gc && disable_moving_gc_count_ != 0) { 1831 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1832 return collector::kGcTypeNone; 1833 } 1834 collector_type_running_ = collector_type_; 1835 } 1836 1837 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1838 ++runtime->GetStats()->gc_for_alloc_count; 1839 ++self->GetStats()->gc_for_alloc_count; 1840 } 1841 uint64_t gc_start_time_ns = NanoTime(); 1842 uint64_t gc_start_size = GetBytesAllocated(); 1843 // Approximate allocation rate in bytes / second. 1844 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1845 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1846 if (LIKELY(ms_delta != 0)) { 1847 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1848 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1849 } 1850 1851 DCHECK_LT(gc_type, collector::kGcTypeMax); 1852 DCHECK_NE(gc_type, collector::kGcTypeNone); 1853 1854 collector::GarbageCollector* collector = nullptr; 1855 // TODO: Clean this up. 1856 if (compacting_gc) { 1857 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1858 current_allocator_ == kAllocatorTypeTLAB); 1859 if (collector_type_ == kCollectorTypeSS || collector_type_ == kCollectorTypeGSS) { 1860 gc_type = semi_space_collector_->GetGcType(); 1861 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1862 semi_space_collector_->SetToSpace(temp_space_); 1863 collector = semi_space_collector_; 1864 } else if (collector_type_ == kCollectorTypeCC) { 1865 gc_type = concurrent_copying_collector_->GetGcType(); 1866 collector = concurrent_copying_collector_; 1867 } else { 1868 LOG(FATAL) << "Unreachable - invalid collector type " << static_cast<size_t>(collector_type_); 1869 } 1870 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1871 CHECK(temp_space_->IsEmpty()); 1872 gc_type = collector::kGcTypeFull; 1873 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1874 current_allocator_ == kAllocatorTypeDlMalloc) { 1875 collector = FindCollectorByGcType(gc_type); 1876 } else { 1877 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1878 } 1879 CHECK(collector != nullptr) 1880 << "Could not find garbage collector with collector_type=" 1881 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1882 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1883 if (compacting_gc) { 1884 runtime->GetThreadList()->SuspendAll(); 1885 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1886 SwapSemiSpaces(); 1887 runtime->GetThreadList()->ResumeAll(); 1888 } else { 1889 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1890 } 1891 total_objects_freed_ever_ += collector->GetFreedObjects(); 1892 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1893 RequestHeapTrim(); 1894 // Enqueue cleared references. 1895 EnqueueClearedReferences(); 1896 // Grow the heap so that we know when to perform the next GC. 1897 GrowForUtilization(collector); 1898 if (CareAboutPauseTimes()) { 1899 const size_t duration = collector->GetDurationNs(); 1900 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1901 // GC for alloc pauses the allocating thread, so consider it as a pause. 1902 bool was_slow = duration > long_gc_log_threshold_ || 1903 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1904 if (!was_slow) { 1905 for (uint64_t pause : pauses) { 1906 was_slow = was_slow || pause > long_pause_log_threshold_; 1907 } 1908 } 1909 if (was_slow) { 1910 const size_t percent_free = GetPercentFree(); 1911 const size_t current_heap_size = GetBytesAllocated(); 1912 const size_t total_memory = GetTotalMemory(); 1913 std::ostringstream pause_string; 1914 for (size_t i = 0; i < pauses.size(); ++i) { 1915 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1916 << ((i != pauses.size() - 1) ? ", " : ""); 1917 } 1918 LOG(INFO) << gc_cause << " " << collector->GetName() 1919 << " GC freed " << collector->GetFreedObjects() << "(" 1920 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1921 << collector->GetFreedLargeObjects() << "(" 1922 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1923 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1924 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1925 << " total " << PrettyDuration((duration / 1000) * 1000); 1926 VLOG(heap) << ConstDumpable<TimingLogger>(collector->GetTimings()); 1927 } 1928 } 1929 FinishGC(self, gc_type); 1930 ATRACE_END(); 1931 1932 // Inform DDMS that a GC completed. 1933 Dbg::GcDidFinish(); 1934 return gc_type; 1935} 1936 1937void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1938 MutexLock mu(self, *gc_complete_lock_); 1939 collector_type_running_ = kCollectorTypeNone; 1940 if (gc_type != collector::kGcTypeNone) { 1941 last_gc_type_ = gc_type; 1942 } 1943 // Wake anyone who may have been waiting for the GC to complete. 1944 gc_complete_cond_->Broadcast(self); 1945} 1946 1947static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1948 RootType /*root_type*/) { 1949 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1950 if (*root == obj) { 1951 LOG(INFO) << "Object " << obj << " is a root"; 1952 } 1953} 1954 1955class ScanVisitor { 1956 public: 1957 void operator()(const mirror::Object* obj) const { 1958 LOG(ERROR) << "Would have rescanned object " << obj; 1959 } 1960}; 1961 1962// Verify a reference from an object. 1963class VerifyReferenceVisitor { 1964 public: 1965 explicit VerifyReferenceVisitor(Heap* heap) 1966 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1967 : heap_(heap), failed_(false) {} 1968 1969 bool Failed() const { 1970 return failed_; 1971 } 1972 1973 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1974 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1975 this->operator()(ref, mirror::Reference::ReferentOffset(), false); 1976 } 1977 1978 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1979 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1980 this->operator()(obj, obj->GetFieldObject<mirror::Object>(offset, false), offset); 1981 } 1982 1983 // TODO: Fix the no thread safety analysis. 1984 void operator()(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1985 NO_THREAD_SAFETY_ANALYSIS { 1986 if (ref == nullptr || IsLive(ref)) { 1987 // Verify that the reference is live. 1988 return; 1989 } 1990 if (!failed_) { 1991 // Print message on only on first failure to prevent spam. 1992 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1993 failed_ = true; 1994 } 1995 if (obj != nullptr) { 1996 accounting::CardTable* card_table = heap_->GetCardTable(); 1997 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1998 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1999 byte* card_addr = card_table->CardFromAddr(obj); 2000 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2001 << offset << "\n card value = " << static_cast<int>(*card_addr); 2002 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2003 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2004 } else { 2005 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2006 } 2007 2008 // Attmept to find the class inside of the recently freed objects. 2009 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2010 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2011 space::MallocSpace* space = ref_space->AsMallocSpace(); 2012 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2013 if (ref_class != nullptr) { 2014 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2015 << PrettyClass(ref_class); 2016 } else { 2017 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2018 } 2019 } 2020 2021 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2022 ref->GetClass()->IsClass()) { 2023 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2024 } else { 2025 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2026 << ") is not a valid heap address"; 2027 } 2028 2029 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2030 void* cover_begin = card_table->AddrFromCard(card_addr); 2031 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2032 accounting::CardTable::kCardSize); 2033 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2034 << "-" << cover_end; 2035 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2036 2037 if (bitmap == nullptr) { 2038 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2039 if (!VerifyClassClass(obj->GetClass())) { 2040 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2041 } 2042 } else { 2043 // Print out how the object is live. 2044 if (bitmap->Test(obj)) { 2045 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2046 } 2047 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2048 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2049 } 2050 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2051 LOG(ERROR) << "Object " << obj << " found in live stack"; 2052 } 2053 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2054 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2055 } 2056 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2057 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2058 } 2059 // Attempt to see if the card table missed the reference. 2060 ScanVisitor scan_visitor; 2061 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2062 card_table->Scan(bitmap, byte_cover_begin, 2063 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2064 } 2065 2066 // Search to see if any of the roots reference our object. 2067 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2068 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2069 2070 // Search to see if any of the roots reference our reference. 2071 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2072 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2073 } else { 2074 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 2075 } 2076 } 2077 2078 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2079 return heap_->IsLiveObjectLocked(obj, true, false, true); 2080 } 2081 2082 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2083 RootType /*root_type*/) { 2084 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2085 (*visitor)(nullptr, *root, MemberOffset(0)); 2086 } 2087 2088 private: 2089 Heap* const heap_; 2090 mutable bool failed_; 2091}; 2092 2093// Verify all references within an object, for use with HeapBitmap::Visit. 2094class VerifyObjectVisitor { 2095 public: 2096 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 2097 2098 void operator()(mirror::Object* obj) const 2099 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2100 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2101 // be live or else how did we find it in the live bitmap? 2102 VerifyReferenceVisitor visitor(heap_); 2103 // The class doesn't count as a reference but we should verify it anyways. 2104 obj->VisitReferences<true>(visitor, visitor); 2105 failed_ = failed_ || visitor.Failed(); 2106 } 2107 2108 static void VisitCallback(mirror::Object* obj, void* arg) 2109 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2110 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2111 visitor->operator()(obj); 2112 } 2113 2114 bool Failed() const { 2115 return failed_; 2116 } 2117 2118 private: 2119 Heap* const heap_; 2120 mutable bool failed_; 2121}; 2122 2123// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2124bool Heap::VerifyHeapReferences() { 2125 Thread* self = Thread::Current(); 2126 Locks::mutator_lock_->AssertExclusiveHeld(self); 2127 // Lets sort our allocation stacks so that we can efficiently binary search them. 2128 allocation_stack_->Sort(); 2129 live_stack_->Sort(); 2130 // Since we sorted the allocation stack content, need to revoke all 2131 // thread-local allocation stacks. 2132 RevokeAllThreadLocalAllocationStacks(self); 2133 VerifyObjectVisitor visitor(this); 2134 // Verify objects in the allocation stack since these will be objects which were: 2135 // 1. Allocated prior to the GC (pre GC verification). 2136 // 2. Allocated during the GC (pre sweep GC verification). 2137 // We don't want to verify the objects in the live stack since they themselves may be 2138 // pointing to dead objects if they are not reachable. 2139 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2140 // Verify the roots: 2141 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor); 2142 if (visitor.Failed()) { 2143 // Dump mod-union tables. 2144 for (const auto& table_pair : mod_union_tables_) { 2145 accounting::ModUnionTable* mod_union_table = table_pair.second; 2146 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2147 } 2148 // Dump remembered sets. 2149 for (const auto& table_pair : remembered_sets_) { 2150 accounting::RememberedSet* remembered_set = table_pair.second; 2151 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2152 } 2153 DumpSpaces(); 2154 return false; 2155 } 2156 return true; 2157} 2158 2159class VerifyReferenceCardVisitor { 2160 public: 2161 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2162 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2163 Locks::heap_bitmap_lock_) 2164 : heap_(heap), failed_(failed) { 2165 } 2166 2167 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2168 // annotalysis on visitors. 2169 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2170 NO_THREAD_SAFETY_ANALYSIS { 2171 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 2172 // Filter out class references since changing an object's class does not mark the card as dirty. 2173 // Also handles large objects, since the only reference they hold is a class reference. 2174 if (ref != nullptr && !ref->IsClass()) { 2175 accounting::CardTable* card_table = heap_->GetCardTable(); 2176 // If the object is not dirty and it is referencing something in the live stack other than 2177 // class, then it must be on a dirty card. 2178 if (!card_table->AddrIsInCardTable(obj)) { 2179 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2180 *failed_ = true; 2181 } else if (!card_table->IsDirty(obj)) { 2182 // TODO: Check mod-union tables. 2183 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2184 // kCardDirty - 1 if it didnt get touched since we aged it. 2185 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2186 if (live_stack->ContainsSorted(ref)) { 2187 if (live_stack->ContainsSorted(obj)) { 2188 LOG(ERROR) << "Object " << obj << " found in live stack"; 2189 } 2190 if (heap_->GetLiveBitmap()->Test(obj)) { 2191 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2192 } 2193 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2194 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2195 2196 // Print which field of the object is dead. 2197 if (!obj->IsObjectArray()) { 2198 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2199 CHECK(klass != NULL); 2200 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2201 : klass->GetIFields(); 2202 CHECK(fields != NULL); 2203 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2204 mirror::ArtField* cur = fields->Get(i); 2205 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2206 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2207 << PrettyField(cur); 2208 break; 2209 } 2210 } 2211 } else { 2212 mirror::ObjectArray<mirror::Object>* object_array = 2213 obj->AsObjectArray<mirror::Object>(); 2214 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2215 if (object_array->Get(i) == ref) { 2216 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2217 } 2218 } 2219 } 2220 2221 *failed_ = true; 2222 } 2223 } 2224 } 2225 } 2226 2227 private: 2228 Heap* const heap_; 2229 bool* const failed_; 2230}; 2231 2232class VerifyLiveStackReferences { 2233 public: 2234 explicit VerifyLiveStackReferences(Heap* heap) 2235 : heap_(heap), 2236 failed_(false) {} 2237 2238 void operator()(mirror::Object* obj) const 2239 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2240 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2241 obj->VisitReferences<true>(visitor); 2242 } 2243 2244 bool Failed() const { 2245 return failed_; 2246 } 2247 2248 private: 2249 Heap* const heap_; 2250 bool failed_; 2251}; 2252 2253bool Heap::VerifyMissingCardMarks() { 2254 Thread* self = Thread::Current(); 2255 Locks::mutator_lock_->AssertExclusiveHeld(self); 2256 2257 // We need to sort the live stack since we binary search it. 2258 live_stack_->Sort(); 2259 // Since we sorted the allocation stack content, need to revoke all 2260 // thread-local allocation stacks. 2261 RevokeAllThreadLocalAllocationStacks(self); 2262 VerifyLiveStackReferences visitor(this); 2263 GetLiveBitmap()->Visit(visitor); 2264 2265 // We can verify objects in the live stack since none of these should reference dead objects. 2266 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2267 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2268 visitor(*it); 2269 } 2270 } 2271 2272 if (visitor.Failed()) { 2273 DumpSpaces(); 2274 return false; 2275 } 2276 return true; 2277} 2278 2279void Heap::SwapStacks(Thread* self) { 2280 if (kUseThreadLocalAllocationStack) { 2281 live_stack_->AssertAllZero(); 2282 } 2283 allocation_stack_.swap(live_stack_); 2284} 2285 2286void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2287 // This must be called only during the pause. 2288 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2289 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2290 MutexLock mu2(self, *Locks::thread_list_lock_); 2291 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2292 for (Thread* t : thread_list) { 2293 t->RevokeThreadLocalAllocationStack(); 2294 } 2295} 2296 2297void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2298 if (kIsDebugBuild) { 2299 if (bump_pointer_space_ != nullptr) { 2300 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2301 } 2302 } 2303} 2304 2305accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2306 auto it = mod_union_tables_.find(space); 2307 if (it == mod_union_tables_.end()) { 2308 return nullptr; 2309 } 2310 return it->second; 2311} 2312 2313accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2314 auto it = remembered_sets_.find(space); 2315 if (it == remembered_sets_.end()) { 2316 return nullptr; 2317 } 2318 return it->second; 2319} 2320 2321void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2322 // Clear cards and keep track of cards cleared in the mod-union table. 2323 for (const auto& space : continuous_spaces_) { 2324 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2325 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2326 if (table != nullptr) { 2327 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2328 "ImageModUnionClearCards"; 2329 TimingLogger::ScopedSplit split(name, &timings); 2330 table->ClearCards(); 2331 } else if (use_rem_sets && rem_set != nullptr) { 2332 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2333 << static_cast<int>(collector_type_); 2334 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2335 rem_set->ClearCards(); 2336 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2337 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2338 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2339 // were dirty before the GC started. 2340 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2341 // -> clean(cleaning thread). 2342 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2343 // roots and then we scan / update mod union tables after. We will always scan either card. 2344 // If we end up with the non aged card, we scan it it in the pause. 2345 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2346 } 2347 } 2348} 2349 2350static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2351} 2352 2353void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2354 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2355 Thread* self = Thread::Current(); 2356 2357 if (verify_pre_gc_heap_) { 2358 thread_list->SuspendAll(); 2359 { 2360 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2361 if (!VerifyHeapReferences()) { 2362 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2363 } 2364 } 2365 thread_list->ResumeAll(); 2366 } 2367 2368 // Check that all objects which reference things in the live stack are on dirty cards. 2369 if (verify_missing_card_marks_) { 2370 thread_list->SuspendAll(); 2371 { 2372 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2373 SwapStacks(self); 2374 // Sort the live stack so that we can quickly binary search it later. 2375 if (!VerifyMissingCardMarks()) { 2376 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2377 } 2378 SwapStacks(self); 2379 } 2380 thread_list->ResumeAll(); 2381 } 2382 2383 if (verify_mod_union_table_) { 2384 thread_list->SuspendAll(); 2385 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2386 for (const auto& table_pair : mod_union_tables_) { 2387 accounting::ModUnionTable* mod_union_table = table_pair.second; 2388 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2389 mod_union_table->Verify(); 2390 } 2391 thread_list->ResumeAll(); 2392 } 2393} 2394 2395void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2396 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2397 // reachable objects. 2398 if (verify_post_gc_heap_) { 2399 Thread* self = Thread::Current(); 2400 CHECK_NE(self->GetState(), kRunnable); 2401 { 2402 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2403 // Swapping bound bitmaps does nothing. 2404 gc->SwapBitmaps(); 2405 if (!VerifyHeapReferences()) { 2406 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2407 } 2408 gc->SwapBitmaps(); 2409 } 2410 } 2411} 2412 2413void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2414 if (verify_system_weaks_) { 2415 Thread* self = Thread::Current(); 2416 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2417 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2418 mark_sweep->VerifySystemWeaks(); 2419 } 2420} 2421 2422void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2423 if (verify_pre_gc_rosalloc_) { 2424 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2425 for (const auto& space : continuous_spaces_) { 2426 if (space->IsRosAllocSpace()) { 2427 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2428 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2429 rosalloc_space->Verify(); 2430 } 2431 } 2432 } 2433} 2434 2435void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2436 if (verify_post_gc_rosalloc_) { 2437 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2438 for (const auto& space : continuous_spaces_) { 2439 if (space->IsRosAllocSpace()) { 2440 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2441 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2442 rosalloc_space->Verify(); 2443 } 2444 } 2445 } 2446} 2447 2448collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2449 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2450 MutexLock mu(self, *gc_complete_lock_); 2451 return WaitForGcToCompleteLocked(self); 2452} 2453 2454collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2455 collector::GcType last_gc_type = collector::kGcTypeNone; 2456 uint64_t wait_start = NanoTime(); 2457 while (collector_type_running_ != kCollectorTypeNone) { 2458 ATRACE_BEGIN("GC: Wait For Completion"); 2459 // We must wait, change thread state then sleep on gc_complete_cond_; 2460 gc_complete_cond_->Wait(self); 2461 last_gc_type = last_gc_type_; 2462 ATRACE_END(); 2463 } 2464 uint64_t wait_time = NanoTime() - wait_start; 2465 total_wait_time_ += wait_time; 2466 if (wait_time > long_pause_log_threshold_) { 2467 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2468 } 2469 return last_gc_type; 2470} 2471 2472void Heap::DumpForSigQuit(std::ostream& os) { 2473 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2474 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2475 DumpGcPerformanceInfo(os); 2476} 2477 2478size_t Heap::GetPercentFree() { 2479 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2480} 2481 2482void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2483 if (max_allowed_footprint > GetMaxMemory()) { 2484 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2485 << PrettySize(GetMaxMemory()); 2486 max_allowed_footprint = GetMaxMemory(); 2487 } 2488 max_allowed_footprint_ = max_allowed_footprint; 2489} 2490 2491bool Heap::IsMovableObject(const mirror::Object* obj) const { 2492 if (kMovingCollector) { 2493 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2494 if (space != nullptr) { 2495 // TODO: Check large object? 2496 return space->CanMoveObjects(); 2497 } 2498 } 2499 return false; 2500} 2501 2502void Heap::UpdateMaxNativeFootprint() { 2503 size_t native_size = native_bytes_allocated_; 2504 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2505 size_t target_size = native_size / GetTargetHeapUtilization(); 2506 if (target_size > native_size + max_free_) { 2507 target_size = native_size + max_free_; 2508 } else if (target_size < native_size + min_free_) { 2509 target_size = native_size + min_free_; 2510 } 2511 native_footprint_gc_watermark_ = target_size; 2512 native_footprint_limit_ = 2 * target_size - native_size; 2513} 2514 2515collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2516 for (const auto& collector : garbage_collectors_) { 2517 if (collector->GetCollectorType() == collector_type_ && 2518 collector->GetGcType() == gc_type) { 2519 return collector; 2520 } 2521 } 2522 return nullptr; 2523} 2524 2525void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2526 // We know what our utilization is at this moment. 2527 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2528 const size_t bytes_allocated = GetBytesAllocated(); 2529 last_gc_size_ = bytes_allocated; 2530 last_gc_time_ns_ = NanoTime(); 2531 size_t target_size; 2532 collector::GcType gc_type = collector_ran->GetGcType(); 2533 if (gc_type != collector::kGcTypeSticky) { 2534 // Grow the heap for non sticky GC. 2535 target_size = bytes_allocated / GetTargetHeapUtilization(); 2536 if (target_size > bytes_allocated + max_free_) { 2537 target_size = bytes_allocated + max_free_; 2538 } else if (target_size < bytes_allocated + min_free_) { 2539 target_size = bytes_allocated + min_free_; 2540 } 2541 native_need_to_run_finalization_ = true; 2542 next_gc_type_ = collector::kGcTypeSticky; 2543 } else { 2544 collector::GcType non_sticky_gc_type = 2545 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2546 // Find what the next non sticky collector will be. 2547 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2548 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2549 // do another sticky collection next. 2550 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2551 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2552 // if the sticky GC throughput always remained >= the full/partial throughput. 2553 if (collector_ran->GetEstimatedLastIterationThroughput() * kStickyGcThroughputAdjustment >= 2554 non_sticky_collector->GetEstimatedMeanThroughput() && 2555 non_sticky_collector->GetIterations() > 0 && 2556 bytes_allocated <= max_allowed_footprint_) { 2557 next_gc_type_ = collector::kGcTypeSticky; 2558 } else { 2559 next_gc_type_ = non_sticky_gc_type; 2560 } 2561 // If we have freed enough memory, shrink the heap back down. 2562 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2563 target_size = bytes_allocated + max_free_; 2564 } else { 2565 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2566 } 2567 } 2568 if (!ignore_max_footprint_) { 2569 SetIdealFootprint(target_size); 2570 if (IsGcConcurrent()) { 2571 // Calculate when to perform the next ConcurrentGC. 2572 // Calculate the estimated GC duration. 2573 const double gc_duration_seconds = NsToMs(collector_ran->GetDurationNs()) / 1000.0; 2574 // Estimate how many remaining bytes we will have when we need to start the next GC. 2575 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2576 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2577 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2578 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2579 // A never going to happen situation that from the estimated allocation rate we will exceed 2580 // the applications entire footprint with the given estimated allocation rate. Schedule 2581 // another GC nearly straight away. 2582 remaining_bytes = kMinConcurrentRemainingBytes; 2583 } 2584 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2585 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2586 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2587 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2588 // right away. 2589 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2590 } 2591 } 2592} 2593 2594void Heap::ClearGrowthLimit() { 2595 growth_limit_ = capacity_; 2596 non_moving_space_->ClearGrowthLimit(); 2597} 2598 2599void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2600 ScopedObjectAccess soa(self); 2601 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(object)); 2602 jvalue args[1]; 2603 args[0].l = arg.get(); 2604 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2605} 2606 2607void Heap::EnqueueClearedReferences() { 2608 Thread* self = Thread::Current(); 2609 Locks::mutator_lock_->AssertNotHeld(self); 2610 if (!cleared_references_.IsEmpty()) { 2611 // When a runtime isn't started there are no reference queues to care about so ignore. 2612 if (LIKELY(Runtime::Current()->IsStarted())) { 2613 ScopedObjectAccess soa(self); 2614 ScopedLocalRef<jobject> arg(self->GetJniEnv(), 2615 soa.AddLocalReference<jobject>(cleared_references_.GetList())); 2616 jvalue args[1]; 2617 args[0].l = arg.get(); 2618 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_ReferenceQueue_add, args); 2619 } 2620 cleared_references_.Clear(); 2621 } 2622} 2623 2624void Heap::RequestConcurrentGC(Thread* self) { 2625 // Make sure that we can do a concurrent GC. 2626 Runtime* runtime = Runtime::Current(); 2627 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2628 self->IsHandlingStackOverflow()) { 2629 return; 2630 } 2631 // We already have a request pending, no reason to start more until we update 2632 // concurrent_start_bytes_. 2633 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2634 JNIEnv* env = self->GetJniEnv(); 2635 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2636 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2637 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2638 WellKnownClasses::java_lang_Daemons_requestGC); 2639 CHECK(!env->ExceptionCheck()); 2640} 2641 2642void Heap::ConcurrentGC(Thread* self) { 2643 if (Runtime::Current()->IsShuttingDown(self)) { 2644 return; 2645 } 2646 // Wait for any GCs currently running to finish. 2647 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2648 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2649 // instead. E.g. can't do partial, so do full instead. 2650 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2651 collector::kGcTypeNone) { 2652 for (collector::GcType gc_type : gc_plan_) { 2653 // Attempt to run the collector, if we succeed, we are done. 2654 if (gc_type > next_gc_type_ && 2655 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2656 break; 2657 } 2658 } 2659 } 2660 } 2661} 2662 2663void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2664 Thread* self = Thread::Current(); 2665 { 2666 MutexLock mu(self, *heap_trim_request_lock_); 2667 if (desired_collector_type_ == desired_collector_type) { 2668 return; 2669 } 2670 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2671 desired_collector_type_ = desired_collector_type; 2672 } 2673 SignalHeapTrimDaemon(self); 2674} 2675 2676void Heap::RequestHeapTrim() { 2677 // Request a heap trim only if we do not currently care about pause times. 2678 if (CareAboutPauseTimes()) { 2679 return; 2680 } 2681 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2682 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2683 // a space it will hold its lock and can become a cause of jank. 2684 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2685 // forking. 2686 2687 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2688 // because that only marks object heads, so a large array looks like lots of empty space. We 2689 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2690 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2691 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2692 // not how much use we're making of those pages. 2693 2694 Thread* self = Thread::Current(); 2695 Runtime* runtime = Runtime::Current(); 2696 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2697 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2698 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2699 // as we don't hold the lock while requesting the trim). 2700 return; 2701 } 2702 { 2703 MutexLock mu(self, *heap_trim_request_lock_); 2704 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2705 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2706 // just yet. 2707 return; 2708 } 2709 heap_trim_request_pending_ = true; 2710 } 2711 // Notify the daemon thread which will actually do the heap trim. 2712 SignalHeapTrimDaemon(self); 2713} 2714 2715void Heap::SignalHeapTrimDaemon(Thread* self) { 2716 JNIEnv* env = self->GetJniEnv(); 2717 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2718 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2719 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2720 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2721 CHECK(!env->ExceptionCheck()); 2722} 2723 2724void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2725 if (rosalloc_space_ != nullptr) { 2726 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2727 } 2728 if (bump_pointer_space_ != nullptr) { 2729 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2730 } 2731} 2732 2733void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2734 if (rosalloc_space_ != nullptr) { 2735 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2736 } 2737} 2738 2739void Heap::RevokeAllThreadLocalBuffers() { 2740 if (rosalloc_space_ != nullptr) { 2741 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2742 } 2743 if (bump_pointer_space_ != nullptr) { 2744 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2745 } 2746} 2747 2748bool Heap::IsGCRequestPending() const { 2749 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2750} 2751 2752void Heap::RunFinalization(JNIEnv* env) { 2753 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2754 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2755 CHECK(WellKnownClasses::java_lang_System != nullptr); 2756 WellKnownClasses::java_lang_System_runFinalization = 2757 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2758 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2759 } 2760 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2761 WellKnownClasses::java_lang_System_runFinalization); 2762} 2763 2764void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2765 Thread* self = ThreadForEnv(env); 2766 if (native_need_to_run_finalization_) { 2767 RunFinalization(env); 2768 UpdateMaxNativeFootprint(); 2769 native_need_to_run_finalization_ = false; 2770 } 2771 // Total number of native bytes allocated. 2772 native_bytes_allocated_.FetchAndAdd(bytes); 2773 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2774 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2775 collector::kGcTypeFull; 2776 2777 // The second watermark is higher than the gc watermark. If you hit this it means you are 2778 // allocating native objects faster than the GC can keep up with. 2779 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2780 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2781 // Just finished a GC, attempt to run finalizers. 2782 RunFinalization(env); 2783 CHECK(!env->ExceptionCheck()); 2784 } 2785 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2786 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2787 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2788 RunFinalization(env); 2789 native_need_to_run_finalization_ = false; 2790 CHECK(!env->ExceptionCheck()); 2791 } 2792 // We have just run finalizers, update the native watermark since it is very likely that 2793 // finalizers released native managed allocations. 2794 UpdateMaxNativeFootprint(); 2795 } else if (!IsGCRequestPending()) { 2796 if (IsGcConcurrent()) { 2797 RequestConcurrentGC(self); 2798 } else { 2799 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2800 } 2801 } 2802 } 2803} 2804 2805void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2806 int expected_size, new_size; 2807 do { 2808 expected_size = native_bytes_allocated_.Load(); 2809 new_size = expected_size - bytes; 2810 if (UNLIKELY(new_size < 0)) { 2811 ScopedObjectAccess soa(env); 2812 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2813 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2814 "registered as allocated", bytes, expected_size).c_str()); 2815 break; 2816 } 2817 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2818} 2819 2820size_t Heap::GetTotalMemory() const { 2821 size_t ret = 0; 2822 for (const auto& space : continuous_spaces_) { 2823 // Currently don't include the image space. 2824 if (!space->IsImageSpace()) { 2825 ret += space->Size(); 2826 } 2827 } 2828 for (const auto& space : discontinuous_spaces_) { 2829 if (space->IsLargeObjectSpace()) { 2830 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2831 } 2832 } 2833 return ret; 2834} 2835 2836void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2837 DCHECK(mod_union_table != nullptr); 2838 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2839} 2840 2841void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2842 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2843 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2844 strlen(ClassHelper(c).GetDescriptor()) == 0); 2845 CHECK_GE(byte_count, sizeof(mirror::Object)); 2846} 2847 2848void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2849 CHECK(remembered_set != nullptr); 2850 space::Space* space = remembered_set->GetSpace(); 2851 CHECK(space != nullptr); 2852 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2853 remembered_sets_.Put(space, remembered_set); 2854 CHECK(remembered_sets_.find(space) != remembered_sets_.end()); 2855} 2856 2857void Heap::RemoveRememberedSet(space::Space* space) { 2858 CHECK(space != nullptr); 2859 auto it = remembered_sets_.find(space); 2860 CHECK(it != remembered_sets_.end()); 2861 remembered_sets_.erase(it); 2862 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2863} 2864 2865void Heap::ClearMarkedObjects() { 2866 // Clear all of the spaces' mark bitmaps. 2867 for (const auto& space : GetContinuousSpaces()) { 2868 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2869 if (space->GetLiveBitmap() != mark_bitmap) { 2870 mark_bitmap->Clear(); 2871 } 2872 } 2873 // Clear the marked objects in the discontinous space object sets. 2874 for (const auto& space : GetDiscontinuousSpaces()) { 2875 space->GetMarkObjects()->Clear(); 2876 } 2877} 2878 2879} // namespace gc 2880} // namespace art 2881