heap.cc revision 309e3bfc6a4c682ac09c95c596e11d8678603577
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <vector> 24 25#include "base/histogram-inl.h" 26#include "base/stl_util.h" 27#include "common_throws.h" 28#include "cutils/sched_policy.h" 29#include "debugger.h" 30#include "gc/accounting/atomic_stack.h" 31#include "gc/accounting/card_table-inl.h" 32#include "gc/accounting/heap_bitmap-inl.h" 33#include "gc/accounting/mod_union_table.h" 34#include "gc/accounting/mod_union_table-inl.h" 35#include "gc/accounting/remembered_set.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/concurrent_copying.h" 38#include "gc/collector/mark_sweep-inl.h" 39#include "gc/collector/partial_mark_sweep.h" 40#include "gc/collector/semi_space.h" 41#include "gc/collector/sticky_mark_sweep.h" 42#include "gc/space/bump_pointer_space.h" 43#include "gc/space/dlmalloc_space-inl.h" 44#include "gc/space/image_space.h" 45#include "gc/space/large_object_space.h" 46#include "gc/space/rosalloc_space-inl.h" 47#include "gc/space/space-inl.h" 48#include "gc/space/zygote_space.h" 49#include "entrypoints/quick/quick_alloc_entrypoints.h" 50#include "heap-inl.h" 51#include "image.h" 52#include "mirror/art_field-inl.h" 53#include "mirror/class-inl.h" 54#include "mirror/object.h" 55#include "mirror/object-inl.h" 56#include "mirror/object_array-inl.h" 57#include "mirror/reference-inl.h" 58#include "object_utils.h" 59#include "os.h" 60#include "reflection.h" 61#include "runtime.h" 62#include "ScopedLocalRef.h" 63#include "scoped_thread_state_change.h" 64#include "sirt_ref.h" 65#include "thread_list.h" 66#include "UniquePtr.h" 67#include "well_known_classes.h" 68 69namespace art { 70 71namespace gc { 72 73static constexpr size_t kCollectorTransitionStressIterations = 0; 74static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 75static constexpr bool kGCALotMode = false; 76static constexpr size_t kGcAlotInterval = KB; 77// Minimum amount of remaining bytes before a concurrent GC is triggered. 78static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 79static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 80// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 81// relative to partial/full GC. This is desirable since sticky GCs interfere less with mutator 82// threads (lower pauses, use less memory bandwidth). 83static constexpr double kStickyGcThroughputAdjustment = 1.25; 84// Whether or not we use the free list large object space. 85static constexpr bool kUseFreeListSpaceForLOS = false; 86// Whtehr or not we compact the zygote in PreZygoteFork. 87static constexpr bool kCompactZygote = kMovingCollector; 88static constexpr size_t kNonMovingSpaceCapacity = 64 * MB; 89 90Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 91 double target_utilization, size_t capacity, const std::string& image_file_name, 92 CollectorType foreground_collector_type, CollectorType background_collector_type, 93 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 94 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 95 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 96 bool verify_post_gc_heap, bool verify_pre_gc_rosalloc, 97 bool verify_post_gc_rosalloc) 98 : non_moving_space_(nullptr), 99 rosalloc_space_(nullptr), 100 dlmalloc_space_(nullptr), 101 main_space_(nullptr), 102 collector_type_(kCollectorTypeNone), 103 foreground_collector_type_(foreground_collector_type), 104 background_collector_type_(background_collector_type), 105 desired_collector_type_(foreground_collector_type_), 106 heap_trim_request_lock_(nullptr), 107 last_trim_time_(0), 108 heap_transition_target_time_(0), 109 heap_trim_request_pending_(false), 110 parallel_gc_threads_(parallel_gc_threads), 111 conc_gc_threads_(conc_gc_threads), 112 low_memory_mode_(low_memory_mode), 113 long_pause_log_threshold_(long_pause_log_threshold), 114 long_gc_log_threshold_(long_gc_log_threshold), 115 ignore_max_footprint_(ignore_max_footprint), 116 have_zygote_space_(false), 117 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 118 collector_type_running_(kCollectorTypeNone), 119 last_gc_type_(collector::kGcTypeNone), 120 next_gc_type_(collector::kGcTypePartial), 121 capacity_(capacity), 122 growth_limit_(growth_limit), 123 max_allowed_footprint_(initial_size), 124 native_footprint_gc_watermark_(initial_size), 125 native_footprint_limit_(2 * initial_size), 126 native_need_to_run_finalization_(false), 127 // Initially assume we perceive jank in case the process state is never updated. 128 process_state_(kProcessStateJankPerceptible), 129 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 130 total_bytes_freed_ever_(0), 131 total_objects_freed_ever_(0), 132 num_bytes_allocated_(0), 133 native_bytes_allocated_(0), 134 gc_memory_overhead_(0), 135 verify_missing_card_marks_(false), 136 verify_system_weaks_(false), 137 verify_pre_gc_heap_(verify_pre_gc_heap), 138 verify_post_gc_heap_(verify_post_gc_heap), 139 verify_mod_union_table_(false), 140 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 141 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 142 allocation_rate_(0), 143 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 144 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 145 * verification is enabled, we limit the size of allocation stacks to speed up their 146 * searching. 147 */ 148 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 149 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 150 current_allocator_(kAllocatorTypeDlMalloc), 151 current_non_moving_allocator_(kAllocatorTypeNonMoving), 152 bump_pointer_space_(nullptr), 153 temp_space_(nullptr), 154 min_free_(min_free), 155 max_free_(max_free), 156 target_utilization_(target_utilization), 157 total_wait_time_(0), 158 total_allocation_time_(0), 159 verify_object_mode_(kVerifyObjectModeDisabled), 160 disable_moving_gc_count_(0), 161 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 162 use_tlab_(use_tlab) { 163 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 164 LOG(INFO) << "Heap() entering"; 165 } 166 const bool is_zygote = Runtime::Current()->IsZygote(); 167 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 168 // entrypoints. 169 if (!is_zygote) { 170 large_object_threshold_ = kDefaultLargeObjectThreshold; 171 // Background compaction is currently not supported for command line runs. 172 if (background_collector_type_ != foreground_collector_type_) { 173 LOG(WARNING) << "Disabling background compaction for non zygote"; 174 background_collector_type_ = foreground_collector_type_; 175 } 176 } 177 ChangeCollector(desired_collector_type_); 178 179 live_bitmap_.reset(new accounting::HeapBitmap(this)); 180 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 181 // Requested begin for the alloc space, to follow the mapped image and oat files 182 byte* requested_alloc_space_begin = nullptr; 183 if (!image_file_name.empty()) { 184 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 185 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 186 AddSpace(image_space); 187 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 188 // isn't going to get in the middle 189 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 190 CHECK_GT(oat_file_end_addr, image_space->End()); 191 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 192 } 193 if (is_zygote) { 194 // Reserve the address range before we create the non moving space to make sure bitmaps don't 195 // take it. 196 std::string error_str; 197 MemMap* mem_map = MemMap::MapAnonymous( 198 "main space", requested_alloc_space_begin + kNonMovingSpaceCapacity, capacity, 199 PROT_READ | PROT_WRITE, true, &error_str); 200 CHECK(mem_map != nullptr) << error_str; 201 // Non moving space is always dlmalloc since we currently don't have support for multiple 202 // rosalloc spaces. 203 non_moving_space_ = space::DlMallocSpace::Create( 204 "zygote / non moving space", initial_size, kNonMovingSpaceCapacity, kNonMovingSpaceCapacity, 205 requested_alloc_space_begin, false); 206 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 207 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 208 } else { 209 std::string error_str; 210 MemMap* mem_map = MemMap::MapAnonymous("main/non-moving space", requested_alloc_space_begin, 211 capacity, PROT_READ | PROT_WRITE, true, &error_str); 212 CHECK(mem_map != nullptr) << error_str; 213 // Create the main free list space, which doubles as the non moving space. We can do this since 214 // non zygote means that we won't have any background compaction. 215 CreateMainMallocSpace(mem_map, initial_size, growth_limit, capacity); 216 non_moving_space_ = main_space_; 217 } 218 CHECK(non_moving_space_ != nullptr); 219 220 // We need to create the bump pointer if the foreground collector is a compacting GC. We only 221 // create the bump pointer space if we are not a moving foreground collector but have a moving 222 // background collector since the heap transition code will create the temp space by recycling 223 // the bitmap from the main space. 224 if (kMovingCollector) { 225 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 226 // TODO: Not create all the bump pointer spaces if not necessary (currently only GSS needs all 227 // 2 of bump pointer spaces + main space) b/14059466. Divide by 2 for a temporary fix. 228 const size_t bump_pointer_space_capacity = capacity / 2; 229 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 230 bump_pointer_space_capacity, nullptr); 231 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 232 AddSpace(bump_pointer_space_); 233 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 234 bump_pointer_space_capacity, nullptr); 235 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 236 AddSpace(temp_space_); 237 } 238 if (non_moving_space_ != main_space_) { 239 AddSpace(non_moving_space_); 240 } 241 if (main_space_ != nullptr) { 242 AddSpace(main_space_); 243 } 244 245 // Allocate the large object space. 246 if (kUseFreeListSpaceForLOS) { 247 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 248 } else { 249 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 250 } 251 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 252 AddSpace(large_object_space_); 253 254 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 255 CHECK(!continuous_spaces_.empty()); 256 257 // Relies on the spaces being sorted. 258 byte* heap_begin = continuous_spaces_.front()->Begin(); 259 byte* heap_end = continuous_spaces_.back()->Limit(); 260 size_t heap_capacity = heap_end - heap_begin; 261 262 // Allocate the card table. 263 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 264 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 265 266 // Card cache for now since it makes it easier for us to update the references to the copying 267 // spaces. 268 accounting::ModUnionTable* mod_union_table = 269 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 270 GetImageSpace()); 271 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 272 AddModUnionTable(mod_union_table); 273 274 if (collector::SemiSpace::kUseRememberedSet) { 275 accounting::RememberedSet* non_moving_space_rem_set = 276 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 277 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 278 AddRememberedSet(non_moving_space_rem_set); 279 if (main_space_ != nullptr && main_space_ != non_moving_space_) { 280 accounting::RememberedSet* main_space_rem_set = 281 new accounting::RememberedSet("Main space remembered set", this, main_space_); 282 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 283 AddRememberedSet(main_space_rem_set); 284 } 285 } 286 287 // TODO: Count objects in the image space here. 288 num_bytes_allocated_ = 0; 289 290 // Default mark stack size in bytes. 291 static const size_t default_mark_stack_size = 64 * KB; 292 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 293 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 294 max_allocation_stack_size_)); 295 live_stack_.reset(accounting::ObjectStack::Create("live stack", 296 max_allocation_stack_size_)); 297 298 // It's still too early to take a lock because there are no threads yet, but we can create locks 299 // now. We don't create it earlier to make it clear that you can't use locks during heap 300 // initialization. 301 gc_complete_lock_ = new Mutex("GC complete lock"); 302 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 303 *gc_complete_lock_)); 304 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 305 last_gc_size_ = GetBytesAllocated(); 306 307 if (ignore_max_footprint_) { 308 SetIdealFootprint(std::numeric_limits<size_t>::max()); 309 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 310 } 311 CHECK_NE(max_allowed_footprint_, 0U); 312 313 // Create our garbage collectors. 314 for (size_t i = 0; i < 2; ++i) { 315 const bool concurrent = i != 0; 316 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 317 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 318 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 319 } 320 if (kMovingCollector) { 321 // TODO: Clean this up. 322 bool generational = foreground_collector_type_ == kCollectorTypeGSS; 323 semi_space_collector_ = new collector::SemiSpace(this, generational, 324 generational ? "generational" : ""); 325 garbage_collectors_.push_back(semi_space_collector_); 326 327 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 328 garbage_collectors_.push_back(concurrent_copying_collector_); 329 } 330 331 if (running_on_valgrind_) { 332 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 333 } 334 335 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 336 LOG(INFO) << "Heap() exiting"; 337 } 338} 339 340void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 341 size_t capacity) { 342 // Is background compaction is enabled? 343 bool can_move_objects = IsMovingGc(background_collector_type_) != 344 IsMovingGc(foreground_collector_type_); 345 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 346 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 347 // from the main space to the zygote space. If background compaction is enabled, always pass in 348 // that we can move objets. 349 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 350 // After the zygote we want this to be false if we don't have background compaction enabled so 351 // that getting primitive array elements is faster. 352 can_move_objects = !have_zygote_space_; 353 } 354 if (kUseRosAlloc) { 355 main_space_ = space::RosAllocSpace::CreateFromMemMap(mem_map, "main rosalloc space", 356 kDefaultStartingSize, initial_size, 357 growth_limit, capacity, low_memory_mode_, 358 can_move_objects); 359 CHECK(main_space_ != nullptr) << "Failed to create rosalloc space"; 360 } else { 361 main_space_ = space::DlMallocSpace::CreateFromMemMap(mem_map, "main dlmalloc space", 362 kDefaultStartingSize, initial_size, 363 growth_limit, capacity, 364 can_move_objects); 365 CHECK(main_space_ != nullptr) << "Failed to create dlmalloc space"; 366 } 367 main_space_->SetFootprintLimit(main_space_->Capacity()); 368 VLOG(heap) << "Created main space " << main_space_; 369} 370 371void Heap::ChangeAllocator(AllocatorType allocator) { 372 if (current_allocator_ != allocator) { 373 // These two allocators are only used internally and don't have any entrypoints. 374 CHECK_NE(allocator, kAllocatorTypeLOS); 375 CHECK_NE(allocator, kAllocatorTypeNonMoving); 376 current_allocator_ = allocator; 377 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 378 SetQuickAllocEntryPointsAllocator(current_allocator_); 379 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 380 } 381} 382 383void Heap::DisableCompaction() { 384 if (IsMovingGc(foreground_collector_type_)) { 385 foreground_collector_type_ = kCollectorTypeCMS; 386 } 387 if (IsMovingGc(background_collector_type_)) { 388 background_collector_type_ = foreground_collector_type_; 389 } 390 TransitionCollector(foreground_collector_type_); 391} 392 393std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 394 if (!IsValidContinuousSpaceObjectAddress(klass)) { 395 return StringPrintf("<non heap address klass %p>", klass); 396 } 397 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 398 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 399 std::string result("["); 400 result += SafeGetClassDescriptor(component_type); 401 return result; 402 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 403 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 404 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 405 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 406 } else { 407 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 408 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 409 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 410 } 411 const DexFile* dex_file = dex_cache->GetDexFile(); 412 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 413 if (class_def_idx == DexFile::kDexNoIndex16) { 414 return "<class def not found>"; 415 } 416 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 417 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 418 return dex_file->GetTypeDescriptor(type_id); 419 } 420} 421 422std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 423 if (obj == nullptr) { 424 return "null"; 425 } 426 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 427 if (klass == nullptr) { 428 return "(class=null)"; 429 } 430 std::string result(SafeGetClassDescriptor(klass)); 431 if (obj->IsClass()) { 432 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 433 } 434 return result; 435} 436 437void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 438 if (obj == nullptr) { 439 stream << "(obj=null)"; 440 return; 441 } 442 if (IsAligned<kObjectAlignment>(obj)) { 443 space::Space* space = nullptr; 444 // Don't use find space since it only finds spaces which actually contain objects instead of 445 // spaces which may contain objects (e.g. cleared bump pointer spaces). 446 for (const auto& cur_space : continuous_spaces_) { 447 if (cur_space->HasAddress(obj)) { 448 space = cur_space; 449 break; 450 } 451 } 452 // Unprotect all the spaces. 453 for (const auto& space : continuous_spaces_) { 454 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 455 } 456 stream << "Object " << obj; 457 if (space != nullptr) { 458 stream << " in space " << *space; 459 } 460 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 461 stream << "\nclass=" << klass; 462 if (klass != nullptr) { 463 stream << " type= " << SafePrettyTypeOf(obj); 464 } 465 // Re-protect the address we faulted on. 466 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 467 } 468} 469 470bool Heap::IsCompilingBoot() const { 471 for (const auto& space : continuous_spaces_) { 472 if (space->IsImageSpace() || space->IsZygoteSpace()) { 473 return false; 474 } 475 } 476 return true; 477} 478 479bool Heap::HasImageSpace() const { 480 for (const auto& space : continuous_spaces_) { 481 if (space->IsImageSpace()) { 482 return true; 483 } 484 } 485 return false; 486} 487 488void Heap::IncrementDisableMovingGC(Thread* self) { 489 // Need to do this holding the lock to prevent races where the GC is about to run / running when 490 // we attempt to disable it. 491 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 492 MutexLock mu(self, *gc_complete_lock_); 493 ++disable_moving_gc_count_; 494 if (IsMovingGc(collector_type_running_)) { 495 WaitForGcToCompleteLocked(self); 496 } 497} 498 499void Heap::DecrementDisableMovingGC(Thread* self) { 500 MutexLock mu(self, *gc_complete_lock_); 501 CHECK_GE(disable_moving_gc_count_, 0U); 502 --disable_moving_gc_count_; 503} 504 505void Heap::UpdateProcessState(ProcessState process_state) { 506 if (process_state_ != process_state) { 507 process_state_ = process_state; 508 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 509 // Start at index 1 to avoid "is always false" warning. 510 // Have iteration 1 always transition the collector. 511 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 512 ? foreground_collector_type_ : background_collector_type_); 513 usleep(kCollectorTransitionStressWait); 514 } 515 if (process_state_ == kProcessStateJankPerceptible) { 516 // Transition back to foreground right away to prevent jank. 517 RequestCollectorTransition(foreground_collector_type_, 0); 518 } else { 519 // Don't delay for debug builds since we may want to stress test the GC. 520 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 521 kCollectorTransitionWait); 522 } 523 } 524} 525 526void Heap::CreateThreadPool() { 527 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 528 if (num_threads != 0) { 529 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 530 } 531} 532 533void Heap::VisitObjects(ObjectCallback callback, void* arg) { 534 Thread* self = Thread::Current(); 535 // GCs can move objects, so don't allow this. 536 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 537 if (bump_pointer_space_ != nullptr) { 538 // Visit objects in bump pointer space. 539 bump_pointer_space_->Walk(callback, arg); 540 } 541 // TODO: Switch to standard begin and end to use ranged a based loop. 542 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 543 it < end; ++it) { 544 mirror::Object* obj = *it; 545 if (obj != nullptr && obj->GetClass() != nullptr) { 546 // Avoid the race condition caused by the object not yet being written into the allocation 547 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 548 // there can be nulls on the allocation stack. 549 callback(obj, arg); 550 } 551 } 552 GetLiveBitmap()->Walk(callback, arg); 553 self->EndAssertNoThreadSuspension(old_cause); 554} 555 556void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 557 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 558 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 559 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 560 // TODO: Generalize this to n bitmaps? 561 if (space1 == nullptr) { 562 DCHECK(space2 != nullptr); 563 space1 = space2; 564 } 565 if (space2 == nullptr) { 566 DCHECK(space1 != nullptr); 567 space2 = space1; 568 } 569 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 570 large_object_space_->GetLiveObjects(), stack); 571} 572 573void Heap::DeleteThreadPool() { 574 thread_pool_.reset(nullptr); 575} 576 577void Heap::AddSpace(space::Space* space, bool set_as_default) { 578 DCHECK(space != nullptr); 579 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 580 if (space->IsContinuousSpace()) { 581 DCHECK(!space->IsDiscontinuousSpace()); 582 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 583 // Continuous spaces don't necessarily have bitmaps. 584 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 585 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 586 if (live_bitmap != nullptr) { 587 DCHECK(mark_bitmap != nullptr); 588 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 589 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 590 } 591 continuous_spaces_.push_back(continuous_space); 592 if (set_as_default) { 593 if (continuous_space->IsDlMallocSpace()) { 594 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 595 } else if (continuous_space->IsRosAllocSpace()) { 596 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 597 } 598 } 599 // Ensure that spaces remain sorted in increasing order of start address. 600 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 601 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 602 return a->Begin() < b->Begin(); 603 }); 604 } else { 605 DCHECK(space->IsDiscontinuousSpace()); 606 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 607 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 608 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 609 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 610 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 611 discontinuous_spaces_.push_back(discontinuous_space); 612 } 613 if (space->IsAllocSpace()) { 614 alloc_spaces_.push_back(space->AsAllocSpace()); 615 } 616} 617 618void Heap::RemoveSpace(space::Space* space) { 619 DCHECK(space != nullptr); 620 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 621 if (space->IsContinuousSpace()) { 622 DCHECK(!space->IsDiscontinuousSpace()); 623 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 624 // Continuous spaces don't necessarily have bitmaps. 625 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 626 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 627 if (live_bitmap != nullptr) { 628 DCHECK(mark_bitmap != nullptr); 629 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 630 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 631 } 632 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 633 DCHECK(it != continuous_spaces_.end()); 634 continuous_spaces_.erase(it); 635 if (continuous_space == dlmalloc_space_) { 636 dlmalloc_space_ = nullptr; 637 } else if (continuous_space == rosalloc_space_) { 638 rosalloc_space_ = nullptr; 639 } 640 if (continuous_space == main_space_) { 641 main_space_ = nullptr; 642 } else if (continuous_space == bump_pointer_space_) { 643 bump_pointer_space_ = nullptr; 644 } else if (continuous_space == temp_space_) { 645 temp_space_ = nullptr; 646 } 647 } else { 648 DCHECK(space->IsDiscontinuousSpace()); 649 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 650 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 651 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 652 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 653 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 654 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 655 discontinuous_space); 656 DCHECK(it != discontinuous_spaces_.end()); 657 discontinuous_spaces_.erase(it); 658 } 659 if (space->IsAllocSpace()) { 660 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 661 DCHECK(it != alloc_spaces_.end()); 662 alloc_spaces_.erase(it); 663 } 664} 665 666void Heap::RegisterGCAllocation(size_t bytes) { 667 if (this != nullptr) { 668 gc_memory_overhead_.FetchAndAdd(bytes); 669 } 670} 671 672void Heap::RegisterGCDeAllocation(size_t bytes) { 673 if (this != nullptr) { 674 gc_memory_overhead_.FetchAndSub(bytes); 675 } 676} 677 678void Heap::DumpGcPerformanceInfo(std::ostream& os) { 679 // Dump cumulative timings. 680 os << "Dumping cumulative Gc timings\n"; 681 uint64_t total_duration = 0; 682 // Dump cumulative loggers for each GC type. 683 uint64_t total_paused_time = 0; 684 for (auto& collector : garbage_collectors_) { 685 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 686 const size_t iterations = logger.GetIterations(); 687 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 688 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 689 os << ConstDumpable<CumulativeLogger>(logger); 690 const uint64_t total_ns = logger.GetTotalNs(); 691 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 692 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 693 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 694 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 695 Histogram<uint64_t>::CumulativeData cumulative_data; 696 pause_histogram.CreateHistogram(&cumulative_data); 697 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 698 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 699 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 700 << collector->GetName() << " freed: " << freed_objects 701 << " objects with total size " << PrettySize(freed_bytes) << "\n" 702 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 703 << PrettySize(freed_bytes / seconds) << "/s\n"; 704 total_duration += total_ns; 705 total_paused_time += total_pause_ns; 706 } 707 collector->ResetMeasurements(); 708 } 709 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 710 if (total_duration != 0) { 711 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 712 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 713 os << "Mean GC size throughput: " 714 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 715 os << "Mean GC object throughput: " 716 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 717 } 718 size_t total_objects_allocated = GetObjectsAllocatedEver(); 719 os << "Total number of allocations: " << total_objects_allocated << "\n"; 720 size_t total_bytes_allocated = GetBytesAllocatedEver(); 721 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 722 if (kMeasureAllocationTime) { 723 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 724 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 725 << "\n"; 726 } 727 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 728 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 729 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 730} 731 732Heap::~Heap() { 733 VLOG(heap) << "Starting ~Heap()"; 734 STLDeleteElements(&garbage_collectors_); 735 // If we don't reset then the mark stack complains in its destructor. 736 allocation_stack_->Reset(); 737 live_stack_->Reset(); 738 STLDeleteValues(&mod_union_tables_); 739 STLDeleteValues(&remembered_sets_); 740 STLDeleteElements(&continuous_spaces_); 741 STLDeleteElements(&discontinuous_spaces_); 742 delete gc_complete_lock_; 743 delete heap_trim_request_lock_; 744 VLOG(heap) << "Finished ~Heap()"; 745} 746 747space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 748 bool fail_ok) const { 749 for (const auto& space : continuous_spaces_) { 750 if (space->Contains(obj)) { 751 return space; 752 } 753 } 754 if (!fail_ok) { 755 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 756 } 757 return NULL; 758} 759 760space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 761 bool fail_ok) const { 762 for (const auto& space : discontinuous_spaces_) { 763 if (space->Contains(obj)) { 764 return space; 765 } 766 } 767 if (!fail_ok) { 768 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 769 } 770 return NULL; 771} 772 773space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 774 space::Space* result = FindContinuousSpaceFromObject(obj, true); 775 if (result != NULL) { 776 return result; 777 } 778 return FindDiscontinuousSpaceFromObject(obj, true); 779} 780 781struct SoftReferenceArgs { 782 IsMarkedCallback* is_marked_callback_; 783 MarkObjectCallback* mark_callback_; 784 void* arg_; 785}; 786 787mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 788 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 789 // TODO: Not preserve all soft references. 790 return args->mark_callback_(obj, args->arg_); 791} 792 793void Heap::ProcessSoftReferences(TimingLogger& timings, bool clear_soft, 794 IsMarkedCallback* is_marked_callback, 795 MarkObjectCallback* mark_object_callback, 796 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 797 // Unless required to clear soft references with white references, preserve some white referents. 798 if (!clear_soft) { 799 // Don't clear for sticky GC. 800 SoftReferenceArgs soft_reference_args; 801 soft_reference_args.is_marked_callback_ = is_marked_callback; 802 soft_reference_args.mark_callback_ = mark_object_callback; 803 soft_reference_args.arg_ = arg; 804 // References with a marked referent are removed from the list. 805 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 806 &soft_reference_args); 807 process_mark_stack_callback(arg); 808 } 809} 810 811// Process reference class instances and schedule finalizations. 812void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 813 IsMarkedCallback* is_marked_callback, 814 MarkObjectCallback* mark_object_callback, 815 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 816 timings.StartSplit("(Paused)ProcessReferences"); 817 ProcessSoftReferences(timings, clear_soft, is_marked_callback, mark_object_callback, 818 process_mark_stack_callback, arg); 819 // Clear all remaining soft and weak references with white referents. 820 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 821 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 822 timings.EndSplit(); 823 // Preserve all white objects with finalize methods and schedule them for finalization. 824 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 825 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 826 mark_object_callback, arg); 827 process_mark_stack_callback(arg); 828 timings.EndSplit(); 829 timings.StartSplit("(Paused)ProcessReferences"); 830 // Clear all f-reachable soft and weak references with white referents. 831 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 832 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 833 // Clear all phantom references with white referents. 834 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 835 // At this point all reference queues other than the cleared references should be empty. 836 DCHECK(soft_reference_queue_.IsEmpty()); 837 DCHECK(weak_reference_queue_.IsEmpty()); 838 DCHECK(finalizer_reference_queue_.IsEmpty()); 839 DCHECK(phantom_reference_queue_.IsEmpty()); 840 timings.EndSplit(); 841} 842 843// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 844// marked, put it on the appropriate list in the heap for later processing. 845void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Reference* ref, 846 IsMarkedCallback is_marked_callback, void* arg) { 847 // klass can be the class of the old object if the visitor already updated the class of ref. 848 DCHECK(klass->IsReferenceClass()); 849 mirror::Object* referent = ref->GetReferent(); 850 if (referent != nullptr) { 851 mirror::Object* forward_address = is_marked_callback(referent, arg); 852 // Null means that the object is not currently marked. 853 if (forward_address == nullptr) { 854 Thread* self = Thread::Current(); 855 // TODO: Remove these locks, and use atomic stacks for storing references? 856 // We need to check that the references haven't already been enqueued since we can end up 857 // scanning the same reference multiple times due to dirty cards. 858 if (klass->IsSoftReferenceClass()) { 859 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 860 } else if (klass->IsWeakReferenceClass()) { 861 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 862 } else if (klass->IsFinalizerReferenceClass()) { 863 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 864 } else if (klass->IsPhantomReferenceClass()) { 865 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 866 } else { 867 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 868 << klass->GetAccessFlags(); 869 } 870 } else if (referent != forward_address) { 871 // Referent is already marked and we need to update it. 872 ref->SetReferent<false>(forward_address); 873 } 874 } 875} 876 877space::ImageSpace* Heap::GetImageSpace() const { 878 for (const auto& space : continuous_spaces_) { 879 if (space->IsImageSpace()) { 880 return space->AsImageSpace(); 881 } 882 } 883 return NULL; 884} 885 886static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 887 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 888 if (used_bytes < chunk_size) { 889 size_t chunk_free_bytes = chunk_size - used_bytes; 890 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 891 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 892 } 893} 894 895void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 896 std::ostringstream oss; 897 size_t total_bytes_free = GetFreeMemory(); 898 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 899 << " free bytes"; 900 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 901 if (!large_object_allocation && total_bytes_free >= byte_count) { 902 size_t max_contiguous_allocation = 0; 903 for (const auto& space : continuous_spaces_) { 904 if (space->IsMallocSpace()) { 905 // To allow the Walk/InspectAll() to exclusively-lock the mutator 906 // lock, temporarily release the shared access to the mutator 907 // lock here by transitioning to the suspended state. 908 Locks::mutator_lock_->AssertSharedHeld(self); 909 self->TransitionFromRunnableToSuspended(kSuspended); 910 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 911 self->TransitionFromSuspendedToRunnable(); 912 Locks::mutator_lock_->AssertSharedHeld(self); 913 } 914 } 915 oss << "; failed due to fragmentation (largest possible contiguous allocation " 916 << max_contiguous_allocation << " bytes)"; 917 } 918 self->ThrowOutOfMemoryError(oss.str().c_str()); 919} 920 921void Heap::DoPendingTransitionOrTrim() { 922 Thread* self = Thread::Current(); 923 CollectorType desired_collector_type; 924 // Wait until we reach the desired transition time. 925 while (true) { 926 uint64_t wait_time; 927 { 928 MutexLock mu(self, *heap_trim_request_lock_); 929 desired_collector_type = desired_collector_type_; 930 uint64_t current_time = NanoTime(); 931 if (current_time >= heap_transition_target_time_) { 932 break; 933 } 934 wait_time = heap_transition_target_time_ - current_time; 935 } 936 ScopedThreadStateChange tsc(self, kSleeping); 937 usleep(wait_time / 1000); // Usleep takes microseconds. 938 } 939 // Transition the collector if the desired collector type is not the same as the current 940 // collector type. 941 TransitionCollector(desired_collector_type); 942 if (!CareAboutPauseTimes()) { 943 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 944 // about pauses. 945 Runtime* runtime = Runtime::Current(); 946 runtime->GetThreadList()->SuspendAll(); 947 runtime->GetMonitorList()->DeflateMonitors(); 948 runtime->GetThreadList()->ResumeAll(); 949 // Do a heap trim if it is needed. 950 Trim(); 951 } 952} 953 954void Heap::Trim() { 955 Thread* self = Thread::Current(); 956 { 957 MutexLock mu(self, *heap_trim_request_lock_); 958 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 959 return; 960 } 961 last_trim_time_ = NanoTime(); 962 heap_trim_request_pending_ = false; 963 } 964 { 965 // Need to do this before acquiring the locks since we don't want to get suspended while 966 // holding any locks. 967 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 968 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 969 // trimming. 970 MutexLock mu(self, *gc_complete_lock_); 971 // Ensure there is only one GC at a time. 972 WaitForGcToCompleteLocked(self); 973 collector_type_running_ = kCollectorTypeHeapTrim; 974 } 975 uint64_t start_ns = NanoTime(); 976 // Trim the managed spaces. 977 uint64_t total_alloc_space_allocated = 0; 978 uint64_t total_alloc_space_size = 0; 979 uint64_t managed_reclaimed = 0; 980 for (const auto& space : continuous_spaces_) { 981 if (space->IsMallocSpace()) { 982 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 983 total_alloc_space_size += alloc_space->Size(); 984 managed_reclaimed += alloc_space->Trim(); 985 } 986 } 987 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 988 if (bump_pointer_space_ != nullptr) { 989 total_alloc_space_allocated -= bump_pointer_space_->Size(); 990 } 991 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 992 static_cast<float>(total_alloc_space_size); 993 uint64_t gc_heap_end_ns = NanoTime(); 994 // We never move things in the native heap, so we can finish the GC at this point. 995 FinishGC(self, collector::kGcTypeNone); 996 // Trim the native heap. 997 dlmalloc_trim(0); 998 size_t native_reclaimed = 0; 999 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1000 uint64_t end_ns = NanoTime(); 1001 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1002 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1003 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1004 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1005 << "%."; 1006} 1007 1008bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1009 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1010 // taking the lock. 1011 if (obj == nullptr) { 1012 return true; 1013 } 1014 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1015} 1016 1017bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1018 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1019} 1020 1021bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1022 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1023 return false; 1024 } 1025 for (const auto& space : continuous_spaces_) { 1026 if (space->HasAddress(obj)) { 1027 return true; 1028 } 1029 } 1030 return false; 1031} 1032 1033bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1034 bool search_live_stack, bool sorted) { 1035 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1036 return false; 1037 } 1038 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1039 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1040 if (obj == klass) { 1041 // This case happens for java.lang.Class. 1042 return true; 1043 } 1044 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1045 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1046 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1047 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1048 return temp_space_->Contains(obj); 1049 } 1050 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1051 space::DiscontinuousSpace* d_space = NULL; 1052 if (c_space != nullptr) { 1053 if (c_space->GetLiveBitmap()->Test(obj)) { 1054 return true; 1055 } 1056 } else { 1057 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1058 if (d_space != nullptr) { 1059 if (d_space->GetLiveObjects()->Test(obj)) { 1060 return true; 1061 } 1062 } 1063 } 1064 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1065 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1066 if (i > 0) { 1067 NanoSleep(MsToNs(10)); 1068 } 1069 if (search_allocation_stack) { 1070 if (sorted) { 1071 if (allocation_stack_->ContainsSorted(obj)) { 1072 return true; 1073 } 1074 } else if (allocation_stack_->Contains(obj)) { 1075 return true; 1076 } 1077 } 1078 1079 if (search_live_stack) { 1080 if (sorted) { 1081 if (live_stack_->ContainsSorted(obj)) { 1082 return true; 1083 } 1084 } else if (live_stack_->Contains(obj)) { 1085 return true; 1086 } 1087 } 1088 } 1089 // We need to check the bitmaps again since there is a race where we mark something as live and 1090 // then clear the stack containing it. 1091 if (c_space != nullptr) { 1092 if (c_space->GetLiveBitmap()->Test(obj)) { 1093 return true; 1094 } 1095 } else { 1096 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1097 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 1098 return true; 1099 } 1100 } 1101 return false; 1102} 1103 1104void Heap::DumpSpaces(std::ostream& stream) { 1105 for (const auto& space : continuous_spaces_) { 1106 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1107 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1108 stream << space << " " << *space << "\n"; 1109 if (live_bitmap != nullptr) { 1110 stream << live_bitmap << " " << *live_bitmap << "\n"; 1111 } 1112 if (mark_bitmap != nullptr) { 1113 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1114 } 1115 } 1116 for (const auto& space : discontinuous_spaces_) { 1117 stream << space << " " << *space << "\n"; 1118 } 1119} 1120 1121void Heap::VerifyObjectBody(mirror::Object* obj) { 1122 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1123 return; 1124 } 1125 // Ignore early dawn of the universe verifications. 1126 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 1127 return; 1128 } 1129 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1130 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 1131 mirror::Object::ClassOffset(), false); 1132 CHECK(c != nullptr) << "Null class in object " << obj; 1133 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1134 CHECK(VerifyClassClass(c)); 1135 1136 if (verify_object_mode_ > kVerifyObjectModeFast) { 1137 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1138 if (!IsLiveObjectLocked(obj)) { 1139 DumpSpaces(); 1140 LOG(FATAL) << "Object is dead: " << obj; 1141 } 1142 } 1143} 1144 1145void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1146 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1147} 1148 1149void Heap::VerifyHeap() { 1150 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1151 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1152} 1153 1154void Heap::RecordFree(ssize_t freed_objects, ssize_t freed_bytes) { 1155 // Use signed comparison since freed bytes can be negative when background compaction foreground 1156 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1157 // free list backed space typically increasing memory footprint due to padding and binning. 1158 DCHECK_LE(freed_bytes, static_cast<ssize_t>(num_bytes_allocated_.Load())); 1159 DCHECK_GE(freed_objects, 0); 1160 num_bytes_allocated_.FetchAndSub(freed_bytes); 1161 if (Runtime::Current()->HasStatsEnabled()) { 1162 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1163 thread_stats->freed_objects += freed_objects; 1164 thread_stats->freed_bytes += freed_bytes; 1165 // TODO: Do this concurrently. 1166 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1167 global_stats->freed_objects += freed_objects; 1168 global_stats->freed_bytes += freed_bytes; 1169 } 1170} 1171 1172mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1173 size_t alloc_size, size_t* bytes_allocated, 1174 size_t* usable_size, 1175 mirror::Class** klass) { 1176 mirror::Object* ptr = nullptr; 1177 bool was_default_allocator = allocator == GetCurrentAllocator(); 1178 DCHECK(klass != nullptr); 1179 SirtRef<mirror::Class> sirt_klass(self, *klass); 1180 // The allocation failed. If the GC is running, block until it completes, and then retry the 1181 // allocation. 1182 collector::GcType last_gc = WaitForGcToComplete(self); 1183 if (last_gc != collector::kGcTypeNone) { 1184 // If we were the default allocator but the allocator changed while we were suspended, 1185 // abort the allocation. 1186 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1187 *klass = sirt_klass.get(); 1188 return nullptr; 1189 } 1190 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1191 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1192 } 1193 1194 collector::GcType tried_type = next_gc_type_; 1195 if (ptr == nullptr) { 1196 const bool gc_ran = 1197 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1198 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1199 *klass = sirt_klass.get(); 1200 return nullptr; 1201 } 1202 if (gc_ran) { 1203 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1204 } 1205 } 1206 1207 // Loop through our different Gc types and try to Gc until we get enough free memory. 1208 for (collector::GcType gc_type : gc_plan_) { 1209 if (ptr != nullptr) { 1210 break; 1211 } 1212 if (gc_type == tried_type) { 1213 continue; 1214 } 1215 // Attempt to run the collector, if we succeed, re-try the allocation. 1216 const bool gc_ran = 1217 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1218 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1219 *klass = sirt_klass.get(); 1220 return nullptr; 1221 } 1222 if (gc_ran) { 1223 // Did we free sufficient memory for the allocation to succeed? 1224 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1225 } 1226 } 1227 // Allocations have failed after GCs; this is an exceptional state. 1228 if (ptr == nullptr) { 1229 // Try harder, growing the heap if necessary. 1230 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1231 } 1232 if (ptr == nullptr) { 1233 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1234 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1235 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1236 // OOME. 1237 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1238 << " allocation"; 1239 // TODO: Run finalization, but this may cause more allocations to occur. 1240 // We don't need a WaitForGcToComplete here either. 1241 DCHECK(!gc_plan_.empty()); 1242 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1243 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1244 *klass = sirt_klass.get(); 1245 return nullptr; 1246 } 1247 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1248 if (ptr == nullptr) { 1249 ThrowOutOfMemoryError(self, alloc_size, false); 1250 } 1251 } 1252 *klass = sirt_klass.get(); 1253 return ptr; 1254} 1255 1256void Heap::SetTargetHeapUtilization(float target) { 1257 DCHECK_GT(target, 0.0f); // asserted in Java code 1258 DCHECK_LT(target, 1.0f); 1259 target_utilization_ = target; 1260} 1261 1262size_t Heap::GetObjectsAllocated() const { 1263 size_t total = 0; 1264 for (space::AllocSpace* space : alloc_spaces_) { 1265 total += space->GetObjectsAllocated(); 1266 } 1267 return total; 1268} 1269 1270size_t Heap::GetObjectsAllocatedEver() const { 1271 return GetObjectsFreedEver() + GetObjectsAllocated(); 1272} 1273 1274size_t Heap::GetBytesAllocatedEver() const { 1275 return GetBytesFreedEver() + GetBytesAllocated(); 1276} 1277 1278class InstanceCounter { 1279 public: 1280 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1281 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1282 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1283 } 1284 static void Callback(mirror::Object* obj, void* arg) 1285 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1286 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1287 mirror::Class* instance_class = obj->GetClass(); 1288 CHECK(instance_class != nullptr); 1289 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1290 if (instance_counter->use_is_assignable_from_) { 1291 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1292 ++instance_counter->counts_[i]; 1293 } 1294 } else if (instance_class == instance_counter->classes_[i]) { 1295 ++instance_counter->counts_[i]; 1296 } 1297 } 1298 } 1299 1300 private: 1301 const std::vector<mirror::Class*>& classes_; 1302 bool use_is_assignable_from_; 1303 uint64_t* const counts_; 1304 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1305}; 1306 1307void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1308 uint64_t* counts) { 1309 // Can't do any GC in this function since this may move classes. 1310 Thread* self = Thread::Current(); 1311 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1312 InstanceCounter counter(classes, use_is_assignable_from, counts); 1313 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1314 VisitObjects(InstanceCounter::Callback, &counter); 1315 self->EndAssertNoThreadSuspension(old_cause); 1316} 1317 1318class InstanceCollector { 1319 public: 1320 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1321 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1322 : class_(c), max_count_(max_count), instances_(instances) { 1323 } 1324 static void Callback(mirror::Object* obj, void* arg) 1325 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1326 DCHECK(arg != nullptr); 1327 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1328 mirror::Class* instance_class = obj->GetClass(); 1329 if (instance_class == instance_collector->class_) { 1330 if (instance_collector->max_count_ == 0 || 1331 instance_collector->instances_.size() < instance_collector->max_count_) { 1332 instance_collector->instances_.push_back(obj); 1333 } 1334 } 1335 } 1336 1337 private: 1338 mirror::Class* class_; 1339 uint32_t max_count_; 1340 std::vector<mirror::Object*>& instances_; 1341 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1342}; 1343 1344void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1345 std::vector<mirror::Object*>& instances) { 1346 // Can't do any GC in this function since this may move classes. 1347 Thread* self = Thread::Current(); 1348 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1349 InstanceCollector collector(c, max_count, instances); 1350 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1351 VisitObjects(&InstanceCollector::Callback, &collector); 1352 self->EndAssertNoThreadSuspension(old_cause); 1353} 1354 1355class ReferringObjectsFinder { 1356 public: 1357 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1358 std::vector<mirror::Object*>& referring_objects) 1359 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1360 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1361 } 1362 1363 static void Callback(mirror::Object* obj, void* arg) 1364 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1365 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1366 } 1367 1368 // For bitmap Visit. 1369 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1370 // annotalysis on visitors. 1371 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1372 o->VisitReferences<true>(*this); 1373 } 1374 1375 // For Object::VisitReferences. 1376 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1377 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1378 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 1379 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1380 referring_objects_.push_back(obj); 1381 } 1382 } 1383 1384 private: 1385 mirror::Object* object_; 1386 uint32_t max_count_; 1387 std::vector<mirror::Object*>& referring_objects_; 1388 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1389}; 1390 1391void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1392 std::vector<mirror::Object*>& referring_objects) { 1393 // Can't do any GC in this function since this may move the object o. 1394 Thread* self = Thread::Current(); 1395 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1396 ReferringObjectsFinder finder(o, max_count, referring_objects); 1397 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1398 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1399 self->EndAssertNoThreadSuspension(old_cause); 1400} 1401 1402void Heap::CollectGarbage(bool clear_soft_references) { 1403 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1404 // last GC will not have necessarily been cleared. 1405 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1406} 1407 1408void Heap::TransitionCollector(CollectorType collector_type) { 1409 if (collector_type == collector_type_) { 1410 return; 1411 } 1412 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1413 << " -> " << static_cast<int>(collector_type); 1414 uint64_t start_time = NanoTime(); 1415 uint32_t before_size = GetTotalMemory(); 1416 uint32_t before_allocated = num_bytes_allocated_.Load(); 1417 ThreadList* tl = Runtime::Current()->GetThreadList(); 1418 Thread* self = Thread::Current(); 1419 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1420 Locks::mutator_lock_->AssertNotHeld(self); 1421 const bool copying_transition = 1422 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1423 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1424 // compacting_gc_disable_count_, this should rarely occurs). 1425 for (;;) { 1426 { 1427 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1428 MutexLock mu(self, *gc_complete_lock_); 1429 // Ensure there is only one GC at a time. 1430 WaitForGcToCompleteLocked(self); 1431 // If someone else beat us to it and changed the collector before we could, exit. 1432 // This is safe to do before the suspend all since we set the collector_type_running_ before 1433 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1434 // then it would get blocked on WaitForGcToCompleteLocked. 1435 if (collector_type == collector_type_) { 1436 return; 1437 } 1438 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1439 if (!copying_transition || disable_moving_gc_count_ == 0) { 1440 // TODO: Not hard code in semi-space collector? 1441 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1442 break; 1443 } 1444 } 1445 usleep(1000); 1446 } 1447 tl->SuspendAll(); 1448 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1449 switch (collector_type) { 1450 case kCollectorTypeSS: 1451 // Fall-through. 1452 case kCollectorTypeGSS: { 1453 if (!IsMovingGc(collector_type_)) { 1454 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1455 // pointer space last transition it will be protected. 1456 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1457 Compact(bump_pointer_space_, main_space_); 1458 } 1459 break; 1460 } 1461 case kCollectorTypeMS: 1462 // Fall through. 1463 case kCollectorTypeCMS: { 1464 if (IsMovingGc(collector_type_)) { 1465 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1466 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1467 Compact(main_space_, bump_pointer_space_); 1468 } 1469 break; 1470 } 1471 default: { 1472 LOG(FATAL) << "Attempted to transition to invalid collector type " 1473 << static_cast<size_t>(collector_type); 1474 break; 1475 } 1476 } 1477 ChangeCollector(collector_type); 1478 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1479 tl->ResumeAll(); 1480 // Can't call into java code with all threads suspended. 1481 EnqueueClearedReferences(); 1482 uint64_t duration = NanoTime() - start_time; 1483 GrowForUtilization(semi_space_collector_); 1484 FinishGC(self, collector::kGcTypeFull); 1485 int32_t after_size = GetTotalMemory(); 1486 int32_t delta_size = before_size - after_size; 1487 int32_t after_allocated = num_bytes_allocated_.Load(); 1488 int32_t delta_allocated = before_allocated - after_allocated; 1489 const std::string saved_bytes_str = 1490 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1491 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1492 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1493 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1494 << PrettySize(delta_size) << " saved"; 1495} 1496 1497void Heap::ChangeCollector(CollectorType collector_type) { 1498 // TODO: Only do this with all mutators suspended to avoid races. 1499 if (collector_type != collector_type_) { 1500 collector_type_ = collector_type; 1501 gc_plan_.clear(); 1502 switch (collector_type_) { 1503 case kCollectorTypeCC: // Fall-through. 1504 case kCollectorTypeSS: // Fall-through. 1505 case kCollectorTypeGSS: { 1506 gc_plan_.push_back(collector::kGcTypeFull); 1507 if (use_tlab_) { 1508 ChangeAllocator(kAllocatorTypeTLAB); 1509 } else { 1510 ChangeAllocator(kAllocatorTypeBumpPointer); 1511 } 1512 break; 1513 } 1514 case kCollectorTypeMS: { 1515 gc_plan_.push_back(collector::kGcTypeSticky); 1516 gc_plan_.push_back(collector::kGcTypePartial); 1517 gc_plan_.push_back(collector::kGcTypeFull); 1518 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1519 break; 1520 } 1521 case kCollectorTypeCMS: { 1522 gc_plan_.push_back(collector::kGcTypeSticky); 1523 gc_plan_.push_back(collector::kGcTypePartial); 1524 gc_plan_.push_back(collector::kGcTypeFull); 1525 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1526 break; 1527 } 1528 default: { 1529 LOG(FATAL) << "Unimplemented"; 1530 } 1531 } 1532 if (IsGcConcurrent()) { 1533 concurrent_start_bytes_ = 1534 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1535 } else { 1536 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1537 } 1538 } 1539} 1540 1541// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1542class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1543 public: 1544 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1545 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1546 } 1547 1548 void BuildBins(space::ContinuousSpace* space) { 1549 bin_live_bitmap_ = space->GetLiveBitmap(); 1550 bin_mark_bitmap_ = space->GetMarkBitmap(); 1551 BinContext context; 1552 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1553 context.collector_ = this; 1554 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1555 // Note: This requires traversing the space in increasing order of object addresses. 1556 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1557 // Add the last bin which spans after the last object to the end of the space. 1558 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1559 } 1560 1561 private: 1562 struct BinContext { 1563 uintptr_t prev_; // The end of the previous object. 1564 ZygoteCompactingCollector* collector_; 1565 }; 1566 // Maps from bin sizes to locations. 1567 std::multimap<size_t, uintptr_t> bins_; 1568 // Live bitmap of the space which contains the bins. 1569 accounting::SpaceBitmap* bin_live_bitmap_; 1570 // Mark bitmap of the space which contains the bins. 1571 accounting::SpaceBitmap* bin_mark_bitmap_; 1572 1573 static void Callback(mirror::Object* obj, void* arg) 1574 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1575 DCHECK(arg != nullptr); 1576 BinContext* context = reinterpret_cast<BinContext*>(arg); 1577 ZygoteCompactingCollector* collector = context->collector_; 1578 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1579 size_t bin_size = object_addr - context->prev_; 1580 // Add the bin consisting of the end of the previous object to the start of the current object. 1581 collector->AddBin(bin_size, context->prev_); 1582 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1583 } 1584 1585 void AddBin(size_t size, uintptr_t position) { 1586 if (size != 0) { 1587 bins_.insert(std::make_pair(size, position)); 1588 } 1589 } 1590 1591 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1592 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1593 // allocator. 1594 return false; 1595 } 1596 1597 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1598 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1599 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1600 mirror::Object* forward_address; 1601 // Find the smallest bin which we can move obj in. 1602 auto it = bins_.lower_bound(object_size); 1603 if (it == bins_.end()) { 1604 // No available space in the bins, place it in the target space instead (grows the zygote 1605 // space). 1606 size_t bytes_allocated; 1607 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1608 if (to_space_live_bitmap_ != nullptr) { 1609 to_space_live_bitmap_->Set(forward_address); 1610 } else { 1611 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1612 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1613 } 1614 } else { 1615 size_t size = it->first; 1616 uintptr_t pos = it->second; 1617 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1618 forward_address = reinterpret_cast<mirror::Object*>(pos); 1619 // Set the live and mark bits so that sweeping system weaks works properly. 1620 bin_live_bitmap_->Set(forward_address); 1621 bin_mark_bitmap_->Set(forward_address); 1622 DCHECK_GE(size, object_size); 1623 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1624 } 1625 // Copy the object over to its new location. 1626 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1627 if (kUseBakerOrBrooksReadBarrier) { 1628 obj->AssertReadBarrierPointer(); 1629 if (kUseBrooksReadBarrier) { 1630 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1631 forward_address->SetReadBarrierPointer(forward_address); 1632 } 1633 forward_address->AssertReadBarrierPointer(); 1634 } 1635 return forward_address; 1636 } 1637}; 1638 1639void Heap::UnBindBitmaps() { 1640 for (const auto& space : GetContinuousSpaces()) { 1641 if (space->IsContinuousMemMapAllocSpace()) { 1642 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1643 if (alloc_space->HasBoundBitmaps()) { 1644 alloc_space->UnBindBitmaps(); 1645 } 1646 } 1647 } 1648} 1649 1650void Heap::PreZygoteFork() { 1651 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1652 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1653 Thread* self = Thread::Current(); 1654 MutexLock mu(self, zygote_creation_lock_); 1655 // Try to see if we have any Zygote spaces. 1656 if (have_zygote_space_) { 1657 return; 1658 } 1659 VLOG(heap) << "Starting PreZygoteFork"; 1660 // Trim the pages at the end of the non moving space. 1661 non_moving_space_->Trim(); 1662 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1663 // there. 1664 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1665 // Change the collector to the post zygote one. 1666 if (kCompactZygote) { 1667 DCHECK(semi_space_collector_ != nullptr); 1668 // Temporarily disable rosalloc verification because the zygote 1669 // compaction will mess up the rosalloc internal metadata. 1670 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1671 ZygoteCompactingCollector zygote_collector(this); 1672 zygote_collector.BuildBins(non_moving_space_); 1673 // Create a new bump pointer space which we will compact into. 1674 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1675 non_moving_space_->Limit()); 1676 // Compact the bump pointer space to a new zygote bump pointer space. 1677 bool reset_main_space = false; 1678 if (IsMovingGc(collector_type_)) { 1679 zygote_collector.SetFromSpace(bump_pointer_space_); 1680 } else { 1681 CHECK(main_space_ != nullptr); 1682 // Copy from the main space. 1683 zygote_collector.SetFromSpace(main_space_); 1684 reset_main_space = true; 1685 } 1686 zygote_collector.SetToSpace(&target_space); 1687 1688 Runtime::Current()->GetThreadList()->SuspendAll(); 1689 zygote_collector.Run(kGcCauseCollectorTransition, false); 1690 if (IsMovingGc(collector_type_)) { 1691 SwapSemiSpaces(); 1692 } 1693 Runtime::Current()->GetThreadList()->ResumeAll(); 1694 1695 if (reset_main_space) { 1696 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1697 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1698 MemMap* mem_map = main_space_->ReleaseMemMap(); 1699 RemoveSpace(main_space_); 1700 delete main_space_; 1701 main_space_ = nullptr; 1702 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1703 AddSpace(main_space_); 1704 } else { 1705 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1706 } 1707 if (temp_space_ != nullptr) { 1708 CHECK(temp_space_->IsEmpty()); 1709 } 1710 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1711 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1712 // Update the end and write out image. 1713 non_moving_space_->SetEnd(target_space.End()); 1714 non_moving_space_->SetLimit(target_space.Limit()); 1715 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1716 } 1717 ChangeCollector(foreground_collector_type_); 1718 // Save the old space so that we can remove it after we complete creating the zygote space. 1719 space::MallocSpace* old_alloc_space = non_moving_space_; 1720 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1721 // the remaining available space. 1722 // Remove the old space before creating the zygote space since creating the zygote space sets 1723 // the old alloc space's bitmaps to nullptr. 1724 RemoveSpace(old_alloc_space); 1725 if (collector::SemiSpace::kUseRememberedSet) { 1726 // Sanity bound check. 1727 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1728 // Remove the remembered set for the now zygote space (the old 1729 // non-moving space). Note now that we have compacted objects into 1730 // the zygote space, the data in the remembered set is no longer 1731 // needed. The zygote space will instead have a mod-union table 1732 // from this point on. 1733 RemoveRememberedSet(old_alloc_space); 1734 } 1735 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1736 low_memory_mode_, 1737 &non_moving_space_); 1738 delete old_alloc_space; 1739 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1740 AddSpace(zygote_space, false); 1741 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1742 AddSpace(non_moving_space_); 1743 have_zygote_space_ = true; 1744 // Enable large object space allocations. 1745 large_object_threshold_ = kDefaultLargeObjectThreshold; 1746 // Create the zygote space mod union table. 1747 accounting::ModUnionTable* mod_union_table = 1748 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1749 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1750 AddModUnionTable(mod_union_table); 1751 if (collector::SemiSpace::kUseRememberedSet) { 1752 // Add a new remembered set for the post-zygote non-moving space. 1753 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1754 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1755 non_moving_space_); 1756 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1757 << "Failed to create post-zygote non-moving space remembered set"; 1758 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1759 } 1760} 1761 1762void Heap::FlushAllocStack() { 1763 MarkAllocStackAsLive(allocation_stack_.get()); 1764 allocation_stack_->Reset(); 1765} 1766 1767void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1768 accounting::SpaceBitmap* bitmap2, 1769 accounting::ObjectSet* large_objects, 1770 accounting::ObjectStack* stack) { 1771 DCHECK(bitmap1 != nullptr); 1772 DCHECK(bitmap2 != nullptr); 1773 mirror::Object** limit = stack->End(); 1774 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1775 const mirror::Object* obj = *it; 1776 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1777 if (bitmap1->HasAddress(obj)) { 1778 bitmap1->Set(obj); 1779 } else if (bitmap2->HasAddress(obj)) { 1780 bitmap2->Set(obj); 1781 } else { 1782 large_objects->Set(obj); 1783 } 1784 } 1785 } 1786} 1787 1788void Heap::SwapSemiSpaces() { 1789 CHECK(bump_pointer_space_ != nullptr); 1790 CHECK(temp_space_ != nullptr); 1791 std::swap(bump_pointer_space_, temp_space_); 1792} 1793 1794void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1795 space::ContinuousMemMapAllocSpace* source_space) { 1796 CHECK(kMovingCollector); 1797 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1798 if (target_space != source_space) { 1799 semi_space_collector_->SetFromSpace(source_space); 1800 semi_space_collector_->SetToSpace(target_space); 1801 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1802 } 1803} 1804 1805collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1806 bool clear_soft_references) { 1807 Thread* self = Thread::Current(); 1808 Runtime* runtime = Runtime::Current(); 1809 // If the heap can't run the GC, silently fail and return that no GC was run. 1810 switch (gc_type) { 1811 case collector::kGcTypePartial: { 1812 if (!have_zygote_space_) { 1813 return collector::kGcTypeNone; 1814 } 1815 break; 1816 } 1817 default: { 1818 // Other GC types don't have any special cases which makes them not runnable. The main case 1819 // here is full GC. 1820 } 1821 } 1822 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1823 Locks::mutator_lock_->AssertNotHeld(self); 1824 if (self->IsHandlingStackOverflow()) { 1825 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1826 } 1827 bool compacting_gc; 1828 { 1829 gc_complete_lock_->AssertNotHeld(self); 1830 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1831 MutexLock mu(self, *gc_complete_lock_); 1832 // Ensure there is only one GC at a time. 1833 WaitForGcToCompleteLocked(self); 1834 compacting_gc = IsMovingGc(collector_type_); 1835 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1836 if (compacting_gc && disable_moving_gc_count_ != 0) { 1837 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1838 return collector::kGcTypeNone; 1839 } 1840 collector_type_running_ = collector_type_; 1841 } 1842 1843 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1844 ++runtime->GetStats()->gc_for_alloc_count; 1845 ++self->GetStats()->gc_for_alloc_count; 1846 } 1847 uint64_t gc_start_time_ns = NanoTime(); 1848 uint64_t gc_start_size = GetBytesAllocated(); 1849 // Approximate allocation rate in bytes / second. 1850 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1851 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1852 if (LIKELY(ms_delta != 0)) { 1853 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1854 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1855 } 1856 1857 DCHECK_LT(gc_type, collector::kGcTypeMax); 1858 DCHECK_NE(gc_type, collector::kGcTypeNone); 1859 1860 collector::GarbageCollector* collector = nullptr; 1861 // TODO: Clean this up. 1862 if (compacting_gc) { 1863 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1864 current_allocator_ == kAllocatorTypeTLAB); 1865 if (collector_type_ == kCollectorTypeSS || collector_type_ == kCollectorTypeGSS) { 1866 gc_type = semi_space_collector_->GetGcType(); 1867 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1868 semi_space_collector_->SetToSpace(temp_space_); 1869 collector = semi_space_collector_; 1870 } else if (collector_type_ == kCollectorTypeCC) { 1871 gc_type = concurrent_copying_collector_->GetGcType(); 1872 collector = concurrent_copying_collector_; 1873 } else { 1874 LOG(FATAL) << "Unreachable - invalid collector type " << static_cast<size_t>(collector_type_); 1875 } 1876 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1877 CHECK(temp_space_->IsEmpty()); 1878 gc_type = collector::kGcTypeFull; 1879 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1880 current_allocator_ == kAllocatorTypeDlMalloc) { 1881 collector = FindCollectorByGcType(gc_type); 1882 } else { 1883 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1884 } 1885 CHECK(collector != nullptr) 1886 << "Could not find garbage collector with collector_type=" 1887 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1888 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1889 if (compacting_gc) { 1890 runtime->GetThreadList()->SuspendAll(); 1891 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1892 SwapSemiSpaces(); 1893 runtime->GetThreadList()->ResumeAll(); 1894 } else { 1895 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1896 } 1897 total_objects_freed_ever_ += collector->GetFreedObjects(); 1898 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1899 RequestHeapTrim(); 1900 // Enqueue cleared references. 1901 EnqueueClearedReferences(); 1902 // Grow the heap so that we know when to perform the next GC. 1903 GrowForUtilization(collector); 1904 if (CareAboutPauseTimes()) { 1905 const size_t duration = collector->GetDurationNs(); 1906 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1907 // GC for alloc pauses the allocating thread, so consider it as a pause. 1908 bool was_slow = duration > long_gc_log_threshold_ || 1909 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1910 if (!was_slow) { 1911 for (uint64_t pause : pauses) { 1912 was_slow = was_slow || pause > long_pause_log_threshold_; 1913 } 1914 } 1915 if (was_slow) { 1916 const size_t percent_free = GetPercentFree(); 1917 const size_t current_heap_size = GetBytesAllocated(); 1918 const size_t total_memory = GetTotalMemory(); 1919 std::ostringstream pause_string; 1920 for (size_t i = 0; i < pauses.size(); ++i) { 1921 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1922 << ((i != pauses.size() - 1) ? ", " : ""); 1923 } 1924 LOG(INFO) << gc_cause << " " << collector->GetName() 1925 << " GC freed " << collector->GetFreedObjects() << "(" 1926 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1927 << collector->GetFreedLargeObjects() << "(" 1928 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1929 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1930 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1931 << " total " << PrettyDuration((duration / 1000) * 1000); 1932 VLOG(heap) << ConstDumpable<TimingLogger>(collector->GetTimings()); 1933 } 1934 } 1935 FinishGC(self, gc_type); 1936 ATRACE_END(); 1937 1938 // Inform DDMS that a GC completed. 1939 Dbg::GcDidFinish(); 1940 return gc_type; 1941} 1942 1943void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1944 MutexLock mu(self, *gc_complete_lock_); 1945 collector_type_running_ = kCollectorTypeNone; 1946 if (gc_type != collector::kGcTypeNone) { 1947 last_gc_type_ = gc_type; 1948 } 1949 // Wake anyone who may have been waiting for the GC to complete. 1950 gc_complete_cond_->Broadcast(self); 1951} 1952 1953static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1954 RootType /*root_type*/) { 1955 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1956 if (*root == obj) { 1957 LOG(INFO) << "Object " << obj << " is a root"; 1958 } 1959} 1960 1961class ScanVisitor { 1962 public: 1963 void operator()(const mirror::Object* obj) const { 1964 LOG(ERROR) << "Would have rescanned object " << obj; 1965 } 1966}; 1967 1968// Verify a reference from an object. 1969class VerifyReferenceVisitor { 1970 public: 1971 explicit VerifyReferenceVisitor(Heap* heap) 1972 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1973 : heap_(heap), failed_(false) {} 1974 1975 bool Failed() const { 1976 return failed_; 1977 } 1978 1979 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1980 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1981 this->operator()(ref, mirror::Reference::ReferentOffset(), false); 1982 } 1983 1984 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1985 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1986 this->operator()(obj, obj->GetFieldObject<mirror::Object>(offset, false), offset); 1987 } 1988 1989 // TODO: Fix the no thread safety analysis. 1990 void operator()(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1991 NO_THREAD_SAFETY_ANALYSIS { 1992 if (ref == nullptr || IsLive(ref)) { 1993 // Verify that the reference is live. 1994 return; 1995 } 1996 if (!failed_) { 1997 // Print message on only on first failure to prevent spam. 1998 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1999 failed_ = true; 2000 } 2001 if (obj != nullptr) { 2002 accounting::CardTable* card_table = heap_->GetCardTable(); 2003 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2004 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2005 byte* card_addr = card_table->CardFromAddr(obj); 2006 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2007 << offset << "\n card value = " << static_cast<int>(*card_addr); 2008 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2009 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2010 } else { 2011 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2012 } 2013 2014 // Attmept to find the class inside of the recently freed objects. 2015 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2016 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2017 space::MallocSpace* space = ref_space->AsMallocSpace(); 2018 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2019 if (ref_class != nullptr) { 2020 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2021 << PrettyClass(ref_class); 2022 } else { 2023 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2024 } 2025 } 2026 2027 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2028 ref->GetClass()->IsClass()) { 2029 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2030 } else { 2031 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2032 << ") is not a valid heap address"; 2033 } 2034 2035 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2036 void* cover_begin = card_table->AddrFromCard(card_addr); 2037 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2038 accounting::CardTable::kCardSize); 2039 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2040 << "-" << cover_end; 2041 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2042 2043 if (bitmap == nullptr) { 2044 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2045 if (!VerifyClassClass(obj->GetClass())) { 2046 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2047 } 2048 } else { 2049 // Print out how the object is live. 2050 if (bitmap->Test(obj)) { 2051 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2052 } 2053 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2054 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2055 } 2056 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2057 LOG(ERROR) << "Object " << obj << " found in live stack"; 2058 } 2059 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2060 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2061 } 2062 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2063 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2064 } 2065 // Attempt to see if the card table missed the reference. 2066 ScanVisitor scan_visitor; 2067 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2068 card_table->Scan(bitmap, byte_cover_begin, 2069 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2070 } 2071 2072 // Search to see if any of the roots reference our object. 2073 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2074 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2075 2076 // Search to see if any of the roots reference our reference. 2077 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2078 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2079 } else { 2080 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 2081 } 2082 } 2083 2084 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2085 return heap_->IsLiveObjectLocked(obj, true, false, true); 2086 } 2087 2088 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2089 RootType /*root_type*/) { 2090 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2091 (*visitor)(nullptr, *root, MemberOffset(0)); 2092 } 2093 2094 private: 2095 Heap* const heap_; 2096 mutable bool failed_; 2097}; 2098 2099// Verify all references within an object, for use with HeapBitmap::Visit. 2100class VerifyObjectVisitor { 2101 public: 2102 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 2103 2104 void operator()(mirror::Object* obj) const 2105 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2106 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2107 // be live or else how did we find it in the live bitmap? 2108 VerifyReferenceVisitor visitor(heap_); 2109 // The class doesn't count as a reference but we should verify it anyways. 2110 obj->VisitReferences<true>(visitor, visitor); 2111 failed_ = failed_ || visitor.Failed(); 2112 } 2113 2114 static void VisitCallback(mirror::Object* obj, void* arg) 2115 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2116 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2117 visitor->operator()(obj); 2118 } 2119 2120 bool Failed() const { 2121 return failed_; 2122 } 2123 2124 private: 2125 Heap* const heap_; 2126 mutable bool failed_; 2127}; 2128 2129// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2130bool Heap::VerifyHeapReferences() { 2131 Thread* self = Thread::Current(); 2132 Locks::mutator_lock_->AssertExclusiveHeld(self); 2133 // Lets sort our allocation stacks so that we can efficiently binary search them. 2134 allocation_stack_->Sort(); 2135 live_stack_->Sort(); 2136 // Since we sorted the allocation stack content, need to revoke all 2137 // thread-local allocation stacks. 2138 RevokeAllThreadLocalAllocationStacks(self); 2139 VerifyObjectVisitor visitor(this); 2140 // Verify objects in the allocation stack since these will be objects which were: 2141 // 1. Allocated prior to the GC (pre GC verification). 2142 // 2. Allocated during the GC (pre sweep GC verification). 2143 // We don't want to verify the objects in the live stack since they themselves may be 2144 // pointing to dead objects if they are not reachable. 2145 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2146 // Verify the roots: 2147 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor); 2148 if (visitor.Failed()) { 2149 // Dump mod-union tables. 2150 for (const auto& table_pair : mod_union_tables_) { 2151 accounting::ModUnionTable* mod_union_table = table_pair.second; 2152 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2153 } 2154 // Dump remembered sets. 2155 for (const auto& table_pair : remembered_sets_) { 2156 accounting::RememberedSet* remembered_set = table_pair.second; 2157 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2158 } 2159 DumpSpaces(); 2160 return false; 2161 } 2162 return true; 2163} 2164 2165class VerifyReferenceCardVisitor { 2166 public: 2167 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2168 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2169 Locks::heap_bitmap_lock_) 2170 : heap_(heap), failed_(failed) { 2171 } 2172 2173 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2174 // annotalysis on visitors. 2175 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2176 NO_THREAD_SAFETY_ANALYSIS { 2177 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 2178 // Filter out class references since changing an object's class does not mark the card as dirty. 2179 // Also handles large objects, since the only reference they hold is a class reference. 2180 if (ref != nullptr && !ref->IsClass()) { 2181 accounting::CardTable* card_table = heap_->GetCardTable(); 2182 // If the object is not dirty and it is referencing something in the live stack other than 2183 // class, then it must be on a dirty card. 2184 if (!card_table->AddrIsInCardTable(obj)) { 2185 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2186 *failed_ = true; 2187 } else if (!card_table->IsDirty(obj)) { 2188 // TODO: Check mod-union tables. 2189 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2190 // kCardDirty - 1 if it didnt get touched since we aged it. 2191 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2192 if (live_stack->ContainsSorted(ref)) { 2193 if (live_stack->ContainsSorted(obj)) { 2194 LOG(ERROR) << "Object " << obj << " found in live stack"; 2195 } 2196 if (heap_->GetLiveBitmap()->Test(obj)) { 2197 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2198 } 2199 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2200 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2201 2202 // Print which field of the object is dead. 2203 if (!obj->IsObjectArray()) { 2204 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2205 CHECK(klass != NULL); 2206 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2207 : klass->GetIFields(); 2208 CHECK(fields != NULL); 2209 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2210 mirror::ArtField* cur = fields->Get(i); 2211 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2212 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2213 << PrettyField(cur); 2214 break; 2215 } 2216 } 2217 } else { 2218 mirror::ObjectArray<mirror::Object>* object_array = 2219 obj->AsObjectArray<mirror::Object>(); 2220 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2221 if (object_array->Get(i) == ref) { 2222 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2223 } 2224 } 2225 } 2226 2227 *failed_ = true; 2228 } 2229 } 2230 } 2231 } 2232 2233 private: 2234 Heap* const heap_; 2235 bool* const failed_; 2236}; 2237 2238class VerifyLiveStackReferences { 2239 public: 2240 explicit VerifyLiveStackReferences(Heap* heap) 2241 : heap_(heap), 2242 failed_(false) {} 2243 2244 void operator()(mirror::Object* obj) const 2245 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2246 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2247 obj->VisitReferences<true>(visitor); 2248 } 2249 2250 bool Failed() const { 2251 return failed_; 2252 } 2253 2254 private: 2255 Heap* const heap_; 2256 bool failed_; 2257}; 2258 2259bool Heap::VerifyMissingCardMarks() { 2260 Thread* self = Thread::Current(); 2261 Locks::mutator_lock_->AssertExclusiveHeld(self); 2262 2263 // We need to sort the live stack since we binary search it. 2264 live_stack_->Sort(); 2265 // Since we sorted the allocation stack content, need to revoke all 2266 // thread-local allocation stacks. 2267 RevokeAllThreadLocalAllocationStacks(self); 2268 VerifyLiveStackReferences visitor(this); 2269 GetLiveBitmap()->Visit(visitor); 2270 2271 // We can verify objects in the live stack since none of these should reference dead objects. 2272 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2273 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2274 visitor(*it); 2275 } 2276 } 2277 2278 if (visitor.Failed()) { 2279 DumpSpaces(); 2280 return false; 2281 } 2282 return true; 2283} 2284 2285void Heap::SwapStacks(Thread* self) { 2286 if (kUseThreadLocalAllocationStack) { 2287 live_stack_->AssertAllZero(); 2288 } 2289 allocation_stack_.swap(live_stack_); 2290} 2291 2292void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2293 // This must be called only during the pause. 2294 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2295 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2296 MutexLock mu2(self, *Locks::thread_list_lock_); 2297 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2298 for (Thread* t : thread_list) { 2299 t->RevokeThreadLocalAllocationStack(); 2300 } 2301} 2302 2303void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2304 if (kIsDebugBuild) { 2305 if (bump_pointer_space_ != nullptr) { 2306 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2307 } 2308 } 2309} 2310 2311accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2312 auto it = mod_union_tables_.find(space); 2313 if (it == mod_union_tables_.end()) { 2314 return nullptr; 2315 } 2316 return it->second; 2317} 2318 2319accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2320 auto it = remembered_sets_.find(space); 2321 if (it == remembered_sets_.end()) { 2322 return nullptr; 2323 } 2324 return it->second; 2325} 2326 2327void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2328 // Clear cards and keep track of cards cleared in the mod-union table. 2329 for (const auto& space : continuous_spaces_) { 2330 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2331 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2332 if (table != nullptr) { 2333 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2334 "ImageModUnionClearCards"; 2335 TimingLogger::ScopedSplit split(name, &timings); 2336 table->ClearCards(); 2337 } else if (use_rem_sets && rem_set != nullptr) { 2338 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2339 << static_cast<int>(collector_type_); 2340 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2341 rem_set->ClearCards(); 2342 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2343 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2344 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2345 // were dirty before the GC started. 2346 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2347 // -> clean(cleaning thread). 2348 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2349 // roots and then we scan / update mod union tables after. We will always scan either card. 2350 // If we end up with the non aged card, we scan it it in the pause. 2351 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2352 } 2353 } 2354} 2355 2356static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2357} 2358 2359void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2360 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2361 Thread* self = Thread::Current(); 2362 2363 if (verify_pre_gc_heap_) { 2364 thread_list->SuspendAll(); 2365 { 2366 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2367 if (!VerifyHeapReferences()) { 2368 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2369 } 2370 } 2371 thread_list->ResumeAll(); 2372 } 2373 2374 // Check that all objects which reference things in the live stack are on dirty cards. 2375 if (verify_missing_card_marks_) { 2376 thread_list->SuspendAll(); 2377 { 2378 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2379 SwapStacks(self); 2380 // Sort the live stack so that we can quickly binary search it later. 2381 if (!VerifyMissingCardMarks()) { 2382 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2383 } 2384 SwapStacks(self); 2385 } 2386 thread_list->ResumeAll(); 2387 } 2388 2389 if (verify_mod_union_table_) { 2390 thread_list->SuspendAll(); 2391 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2392 for (const auto& table_pair : mod_union_tables_) { 2393 accounting::ModUnionTable* mod_union_table = table_pair.second; 2394 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2395 mod_union_table->Verify(); 2396 } 2397 thread_list->ResumeAll(); 2398 } 2399} 2400 2401void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2402 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2403 // reachable objects. 2404 if (verify_post_gc_heap_) { 2405 Thread* self = Thread::Current(); 2406 CHECK_NE(self->GetState(), kRunnable); 2407 { 2408 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2409 // Swapping bound bitmaps does nothing. 2410 gc->SwapBitmaps(); 2411 SwapSemiSpaces(); 2412 if (!VerifyHeapReferences()) { 2413 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2414 } 2415 SwapSemiSpaces(); 2416 gc->SwapBitmaps(); 2417 } 2418 } 2419} 2420 2421void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2422 if (verify_system_weaks_) { 2423 Thread* self = Thread::Current(); 2424 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2425 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2426 mark_sweep->VerifySystemWeaks(); 2427 } 2428} 2429 2430void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2431 if (verify_pre_gc_rosalloc_) { 2432 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2433 for (const auto& space : continuous_spaces_) { 2434 if (space->IsRosAllocSpace()) { 2435 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2436 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2437 rosalloc_space->Verify(); 2438 } 2439 } 2440 } 2441} 2442 2443void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2444 if (verify_post_gc_rosalloc_) { 2445 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2446 for (const auto& space : continuous_spaces_) { 2447 if (space->IsRosAllocSpace()) { 2448 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2449 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2450 rosalloc_space->Verify(); 2451 } 2452 } 2453 } 2454} 2455 2456collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2457 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2458 MutexLock mu(self, *gc_complete_lock_); 2459 return WaitForGcToCompleteLocked(self); 2460} 2461 2462collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2463 collector::GcType last_gc_type = collector::kGcTypeNone; 2464 uint64_t wait_start = NanoTime(); 2465 while (collector_type_running_ != kCollectorTypeNone) { 2466 ATRACE_BEGIN("GC: Wait For Completion"); 2467 // We must wait, change thread state then sleep on gc_complete_cond_; 2468 gc_complete_cond_->Wait(self); 2469 last_gc_type = last_gc_type_; 2470 ATRACE_END(); 2471 } 2472 uint64_t wait_time = NanoTime() - wait_start; 2473 total_wait_time_ += wait_time; 2474 if (wait_time > long_pause_log_threshold_) { 2475 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2476 } 2477 return last_gc_type; 2478} 2479 2480void Heap::DumpForSigQuit(std::ostream& os) { 2481 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2482 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2483 DumpGcPerformanceInfo(os); 2484} 2485 2486size_t Heap::GetPercentFree() { 2487 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2488} 2489 2490void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2491 if (max_allowed_footprint > GetMaxMemory()) { 2492 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2493 << PrettySize(GetMaxMemory()); 2494 max_allowed_footprint = GetMaxMemory(); 2495 } 2496 max_allowed_footprint_ = max_allowed_footprint; 2497} 2498 2499bool Heap::IsMovableObject(const mirror::Object* obj) const { 2500 if (kMovingCollector) { 2501 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2502 if (space != nullptr) { 2503 // TODO: Check large object? 2504 return space->CanMoveObjects(); 2505 } 2506 } 2507 return false; 2508} 2509 2510void Heap::UpdateMaxNativeFootprint() { 2511 size_t native_size = native_bytes_allocated_; 2512 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2513 size_t target_size = native_size / GetTargetHeapUtilization(); 2514 if (target_size > native_size + max_free_) { 2515 target_size = native_size + max_free_; 2516 } else if (target_size < native_size + min_free_) { 2517 target_size = native_size + min_free_; 2518 } 2519 native_footprint_gc_watermark_ = target_size; 2520 native_footprint_limit_ = 2 * target_size - native_size; 2521} 2522 2523collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2524 for (const auto& collector : garbage_collectors_) { 2525 if (collector->GetCollectorType() == collector_type_ && 2526 collector->GetGcType() == gc_type) { 2527 return collector; 2528 } 2529 } 2530 return nullptr; 2531} 2532 2533void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2534 // We know what our utilization is at this moment. 2535 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2536 const size_t bytes_allocated = GetBytesAllocated(); 2537 last_gc_size_ = bytes_allocated; 2538 last_gc_time_ns_ = NanoTime(); 2539 size_t target_size; 2540 collector::GcType gc_type = collector_ran->GetGcType(); 2541 if (gc_type != collector::kGcTypeSticky) { 2542 // Grow the heap for non sticky GC. 2543 target_size = bytes_allocated / GetTargetHeapUtilization(); 2544 if (target_size > bytes_allocated + max_free_) { 2545 target_size = bytes_allocated + max_free_; 2546 } else if (target_size < bytes_allocated + min_free_) { 2547 target_size = bytes_allocated + min_free_; 2548 } 2549 native_need_to_run_finalization_ = true; 2550 next_gc_type_ = collector::kGcTypeSticky; 2551 } else { 2552 collector::GcType non_sticky_gc_type = 2553 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2554 // Find what the next non sticky collector will be. 2555 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2556 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2557 // do another sticky collection next. 2558 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2559 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2560 // if the sticky GC throughput always remained >= the full/partial throughput. 2561 if (collector_ran->GetEstimatedLastIterationThroughput() * kStickyGcThroughputAdjustment >= 2562 non_sticky_collector->GetEstimatedMeanThroughput() && 2563 non_sticky_collector->GetIterations() > 0 && 2564 bytes_allocated <= max_allowed_footprint_) { 2565 next_gc_type_ = collector::kGcTypeSticky; 2566 } else { 2567 next_gc_type_ = non_sticky_gc_type; 2568 } 2569 // If we have freed enough memory, shrink the heap back down. 2570 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2571 target_size = bytes_allocated + max_free_; 2572 } else { 2573 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2574 } 2575 } 2576 if (!ignore_max_footprint_) { 2577 SetIdealFootprint(target_size); 2578 if (IsGcConcurrent()) { 2579 // Calculate when to perform the next ConcurrentGC. 2580 // Calculate the estimated GC duration. 2581 const double gc_duration_seconds = NsToMs(collector_ran->GetDurationNs()) / 1000.0; 2582 // Estimate how many remaining bytes we will have when we need to start the next GC. 2583 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2584 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2585 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2586 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2587 // A never going to happen situation that from the estimated allocation rate we will exceed 2588 // the applications entire footprint with the given estimated allocation rate. Schedule 2589 // another GC nearly straight away. 2590 remaining_bytes = kMinConcurrentRemainingBytes; 2591 } 2592 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2593 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2594 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2595 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2596 // right away. 2597 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2598 } 2599 } 2600} 2601 2602void Heap::ClearGrowthLimit() { 2603 growth_limit_ = capacity_; 2604 non_moving_space_->ClearGrowthLimit(); 2605} 2606 2607void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2608 ScopedObjectAccess soa(self); 2609 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(object)); 2610 jvalue args[1]; 2611 args[0].l = arg.get(); 2612 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2613} 2614 2615void Heap::EnqueueClearedReferences() { 2616 Thread* self = Thread::Current(); 2617 Locks::mutator_lock_->AssertNotHeld(self); 2618 if (!cleared_references_.IsEmpty()) { 2619 // When a runtime isn't started there are no reference queues to care about so ignore. 2620 if (LIKELY(Runtime::Current()->IsStarted())) { 2621 ScopedObjectAccess soa(self); 2622 ScopedLocalRef<jobject> arg(self->GetJniEnv(), 2623 soa.AddLocalReference<jobject>(cleared_references_.GetList())); 2624 jvalue args[1]; 2625 args[0].l = arg.get(); 2626 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_ReferenceQueue_add, args); 2627 } 2628 cleared_references_.Clear(); 2629 } 2630} 2631 2632void Heap::RequestConcurrentGC(Thread* self) { 2633 // Make sure that we can do a concurrent GC. 2634 Runtime* runtime = Runtime::Current(); 2635 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2636 self->IsHandlingStackOverflow()) { 2637 return; 2638 } 2639 // We already have a request pending, no reason to start more until we update 2640 // concurrent_start_bytes_. 2641 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2642 JNIEnv* env = self->GetJniEnv(); 2643 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2644 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2645 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2646 WellKnownClasses::java_lang_Daemons_requestGC); 2647 CHECK(!env->ExceptionCheck()); 2648} 2649 2650void Heap::ConcurrentGC(Thread* self) { 2651 if (Runtime::Current()->IsShuttingDown(self)) { 2652 return; 2653 } 2654 // Wait for any GCs currently running to finish. 2655 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2656 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2657 // instead. E.g. can't do partial, so do full instead. 2658 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2659 collector::kGcTypeNone) { 2660 for (collector::GcType gc_type : gc_plan_) { 2661 // Attempt to run the collector, if we succeed, we are done. 2662 if (gc_type > next_gc_type_ && 2663 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2664 break; 2665 } 2666 } 2667 } 2668 } 2669} 2670 2671void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2672 Thread* self = Thread::Current(); 2673 { 2674 MutexLock mu(self, *heap_trim_request_lock_); 2675 if (desired_collector_type_ == desired_collector_type) { 2676 return; 2677 } 2678 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2679 desired_collector_type_ = desired_collector_type; 2680 } 2681 SignalHeapTrimDaemon(self); 2682} 2683 2684void Heap::RequestHeapTrim() { 2685 // Request a heap trim only if we do not currently care about pause times. 2686 if (CareAboutPauseTimes()) { 2687 return; 2688 } 2689 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2690 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2691 // a space it will hold its lock and can become a cause of jank. 2692 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2693 // forking. 2694 2695 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2696 // because that only marks object heads, so a large array looks like lots of empty space. We 2697 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2698 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2699 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2700 // not how much use we're making of those pages. 2701 2702 Thread* self = Thread::Current(); 2703 Runtime* runtime = Runtime::Current(); 2704 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2705 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2706 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2707 // as we don't hold the lock while requesting the trim). 2708 return; 2709 } 2710 { 2711 MutexLock mu(self, *heap_trim_request_lock_); 2712 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2713 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2714 // just yet. 2715 return; 2716 } 2717 heap_trim_request_pending_ = true; 2718 } 2719 // Notify the daemon thread which will actually do the heap trim. 2720 SignalHeapTrimDaemon(self); 2721} 2722 2723void Heap::SignalHeapTrimDaemon(Thread* self) { 2724 JNIEnv* env = self->GetJniEnv(); 2725 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2726 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2727 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2728 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2729 CHECK(!env->ExceptionCheck()); 2730} 2731 2732void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2733 if (rosalloc_space_ != nullptr) { 2734 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2735 } 2736 if (bump_pointer_space_ != nullptr) { 2737 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2738 } 2739} 2740 2741void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2742 if (rosalloc_space_ != nullptr) { 2743 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2744 } 2745} 2746 2747void Heap::RevokeAllThreadLocalBuffers() { 2748 if (rosalloc_space_ != nullptr) { 2749 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2750 } 2751 if (bump_pointer_space_ != nullptr) { 2752 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2753 } 2754} 2755 2756bool Heap::IsGCRequestPending() const { 2757 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2758} 2759 2760void Heap::RunFinalization(JNIEnv* env) { 2761 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2762 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2763 CHECK(WellKnownClasses::java_lang_System != nullptr); 2764 WellKnownClasses::java_lang_System_runFinalization = 2765 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2766 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2767 } 2768 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2769 WellKnownClasses::java_lang_System_runFinalization); 2770} 2771 2772void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2773 Thread* self = ThreadForEnv(env); 2774 if (native_need_to_run_finalization_) { 2775 RunFinalization(env); 2776 UpdateMaxNativeFootprint(); 2777 native_need_to_run_finalization_ = false; 2778 } 2779 // Total number of native bytes allocated. 2780 native_bytes_allocated_.FetchAndAdd(bytes); 2781 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2782 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2783 collector::kGcTypeFull; 2784 2785 // The second watermark is higher than the gc watermark. If you hit this it means you are 2786 // allocating native objects faster than the GC can keep up with. 2787 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2788 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2789 // Just finished a GC, attempt to run finalizers. 2790 RunFinalization(env); 2791 CHECK(!env->ExceptionCheck()); 2792 } 2793 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2794 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2795 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2796 RunFinalization(env); 2797 native_need_to_run_finalization_ = false; 2798 CHECK(!env->ExceptionCheck()); 2799 } 2800 // We have just run finalizers, update the native watermark since it is very likely that 2801 // finalizers released native managed allocations. 2802 UpdateMaxNativeFootprint(); 2803 } else if (!IsGCRequestPending()) { 2804 if (IsGcConcurrent()) { 2805 RequestConcurrentGC(self); 2806 } else { 2807 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2808 } 2809 } 2810 } 2811} 2812 2813void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2814 int expected_size, new_size; 2815 do { 2816 expected_size = native_bytes_allocated_.Load(); 2817 new_size = expected_size - bytes; 2818 if (UNLIKELY(new_size < 0)) { 2819 ScopedObjectAccess soa(env); 2820 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2821 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2822 "registered as allocated", bytes, expected_size).c_str()); 2823 break; 2824 } 2825 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2826} 2827 2828size_t Heap::GetTotalMemory() const { 2829 size_t ret = 0; 2830 for (const auto& space : continuous_spaces_) { 2831 // Currently don't include the image space. 2832 if (!space->IsImageSpace()) { 2833 ret += space->Size(); 2834 } 2835 } 2836 for (const auto& space : discontinuous_spaces_) { 2837 if (space->IsLargeObjectSpace()) { 2838 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2839 } 2840 } 2841 return ret; 2842} 2843 2844void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2845 DCHECK(mod_union_table != nullptr); 2846 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2847} 2848 2849void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2850 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2851 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2852 strlen(ClassHelper(c).GetDescriptor()) == 0); 2853 CHECK_GE(byte_count, sizeof(mirror::Object)); 2854} 2855 2856void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2857 CHECK(remembered_set != nullptr); 2858 space::Space* space = remembered_set->GetSpace(); 2859 CHECK(space != nullptr); 2860 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2861 remembered_sets_.Put(space, remembered_set); 2862 CHECK(remembered_sets_.find(space) != remembered_sets_.end()); 2863} 2864 2865void Heap::RemoveRememberedSet(space::Space* space) { 2866 CHECK(space != nullptr); 2867 auto it = remembered_sets_.find(space); 2868 CHECK(it != remembered_sets_.end()); 2869 remembered_sets_.erase(it); 2870 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2871} 2872 2873void Heap::ClearMarkedObjects() { 2874 // Clear all of the spaces' mark bitmaps. 2875 for (const auto& space : GetContinuousSpaces()) { 2876 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2877 if (space->GetLiveBitmap() != mark_bitmap) { 2878 mark_bitmap->Clear(); 2879 } 2880 } 2881 // Clear the marked objects in the discontinous space object sets. 2882 for (const auto& space : GetDiscontinuousSpaces()) { 2883 space->GetMarkObjects()->Clear(); 2884 } 2885} 2886 2887} // namespace gc 2888} // namespace art 2889