1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "heap.h" 18 19 #define ATRACE_TAG ATRACE_TAG_DALVIK 20 #include <cutils/trace.h> 21 22 #include <limits> 23 #include <memory> 24 #include <vector> 25 26 #include "base/allocator.h" 27 #include "base/histogram-inl.h" 28 #include "base/stl_util.h" 29 #include "common_throws.h" 30 #include "cutils/sched_policy.h" 31 #include "debugger.h" 32 #include "gc/accounting/atomic_stack.h" 33 #include "gc/accounting/card_table-inl.h" 34 #include "gc/accounting/heap_bitmap-inl.h" 35 #include "gc/accounting/mod_union_table.h" 36 #include "gc/accounting/mod_union_table-inl.h" 37 #include "gc/accounting/remembered_set.h" 38 #include "gc/accounting/space_bitmap-inl.h" 39 #include "gc/collector/concurrent_copying.h" 40 #include "gc/collector/mark_compact.h" 41 #include "gc/collector/mark_sweep-inl.h" 42 #include "gc/collector/partial_mark_sweep.h" 43 #include "gc/collector/semi_space.h" 44 #include "gc/collector/sticky_mark_sweep.h" 45 #include "gc/reference_processor.h" 46 #include "gc/space/bump_pointer_space.h" 47 #include "gc/space/dlmalloc_space-inl.h" 48 #include "gc/space/image_space.h" 49 #include "gc/space/large_object_space.h" 50 #include "gc/space/rosalloc_space-inl.h" 51 #include "gc/space/space-inl.h" 52 #include "gc/space/zygote_space.h" 53 #include "entrypoints/quick/quick_alloc_entrypoints.h" 54 #include "heap-inl.h" 55 #include "image.h" 56 #include "mirror/art_field-inl.h" 57 #include "mirror/class-inl.h" 58 #include "mirror/object.h" 59 #include "mirror/object-inl.h" 60 #include "mirror/object_array-inl.h" 61 #include "mirror/reference-inl.h" 62 #include "os.h" 63 #include "reflection.h" 64 #include "runtime.h" 65 #include "ScopedLocalRef.h" 66 #include "scoped_thread_state_change.h" 67 #include "handle_scope-inl.h" 68 #include "thread_list.h" 69 #include "well_known_classes.h" 70 71 namespace art { 72 73 namespace gc { 74 75 static constexpr size_t kCollectorTransitionStressIterations = 0; 76 static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 77 static constexpr bool kGCALotMode = false; 78 static constexpr size_t kGcAlotInterval = KB; 79 // Minimum amount of remaining bytes before a concurrent GC is triggered. 80 static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 81 static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 82 // Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 83 // relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 84 // threads (lower pauses, use less memory bandwidth). 85 static constexpr double kStickyGcThroughputAdjustment = 1.0; 86 // Whether or not we use the free list large object space. Only use it if USE_ART_LOW_4G_ALLOCATOR 87 // since this means that we have to use the slow msync loop in MemMap::MapAnonymous. 88 #if USE_ART_LOW_4G_ALLOCATOR 89 static constexpr bool kUseFreeListSpaceForLOS = true; 90 #else 91 static constexpr bool kUseFreeListSpaceForLOS = false; 92 #endif 93 // Whether or not we compact the zygote in PreZygoteFork. 94 static constexpr bool kCompactZygote = kMovingCollector; 95 // How many reserve entries are at the end of the allocation stack, these are only needed if the 96 // allocation stack overflows. 97 static constexpr size_t kAllocationStackReserveSize = 1024; 98 // Default mark stack size in bytes. 99 static const size_t kDefaultMarkStackSize = 64 * KB; 100 // Define space name. 101 static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 102 static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 103 static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 104 static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 105 106 Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 107 double target_utilization, double foreground_heap_growth_multiplier, 108 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 109 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 110 CollectorType background_collector_type, size_t parallel_gc_threads, 111 size_t conc_gc_threads, bool low_memory_mode, 112 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 113 bool ignore_max_footprint, bool use_tlab, 114 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 115 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 116 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 117 uint64_t min_interval_homogeneous_space_compaction_by_oom) 118 : non_moving_space_(nullptr), 119 rosalloc_space_(nullptr), 120 dlmalloc_space_(nullptr), 121 main_space_(nullptr), 122 collector_type_(kCollectorTypeNone), 123 foreground_collector_type_(foreground_collector_type), 124 background_collector_type_(background_collector_type), 125 desired_collector_type_(foreground_collector_type_), 126 heap_trim_request_lock_(nullptr), 127 last_trim_time_(0), 128 heap_transition_or_trim_target_time_(0), 129 heap_trim_request_pending_(false), 130 parallel_gc_threads_(parallel_gc_threads), 131 conc_gc_threads_(conc_gc_threads), 132 low_memory_mode_(low_memory_mode), 133 long_pause_log_threshold_(long_pause_log_threshold), 134 long_gc_log_threshold_(long_gc_log_threshold), 135 ignore_max_footprint_(ignore_max_footprint), 136 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 137 have_zygote_space_(false), 138 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 139 collector_type_running_(kCollectorTypeNone), 140 last_gc_type_(collector::kGcTypeNone), 141 next_gc_type_(collector::kGcTypePartial), 142 capacity_(capacity), 143 growth_limit_(growth_limit), 144 max_allowed_footprint_(initial_size), 145 native_footprint_gc_watermark_(initial_size), 146 native_need_to_run_finalization_(false), 147 // Initially assume we perceive jank in case the process state is never updated. 148 process_state_(kProcessStateJankPerceptible), 149 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 150 total_bytes_freed_ever_(0), 151 total_objects_freed_ever_(0), 152 num_bytes_allocated_(0), 153 native_bytes_allocated_(0), 154 verify_missing_card_marks_(false), 155 verify_system_weaks_(false), 156 verify_pre_gc_heap_(verify_pre_gc_heap), 157 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 158 verify_post_gc_heap_(verify_post_gc_heap), 159 verify_mod_union_table_(false), 160 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 161 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 162 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 163 last_gc_time_ns_(NanoTime()), 164 allocation_rate_(0), 165 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 166 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 167 * verification is enabled, we limit the size of allocation stacks to speed up their 168 * searching. 169 */ 170 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 171 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 172 current_allocator_(kAllocatorTypeDlMalloc), 173 current_non_moving_allocator_(kAllocatorTypeNonMoving), 174 bump_pointer_space_(nullptr), 175 temp_space_(nullptr), 176 min_free_(min_free), 177 max_free_(max_free), 178 target_utilization_(target_utilization), 179 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 180 total_wait_time_(0), 181 total_allocation_time_(0), 182 verify_object_mode_(kVerifyObjectModeDisabled), 183 disable_moving_gc_count_(0), 184 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 185 use_tlab_(use_tlab), 186 main_space_backup_(nullptr), 187 min_interval_homogeneous_space_compaction_by_oom_( 188 min_interval_homogeneous_space_compaction_by_oom), 189 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 190 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 191 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 192 LOG(INFO) << "Heap() entering"; 193 } 194 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 195 // entrypoints. 196 const bool is_zygote = Runtime::Current()->IsZygote(); 197 if (!is_zygote) { 198 large_object_threshold_ = kDefaultLargeObjectThreshold; 199 // Background compaction is currently not supported for command line runs. 200 if (background_collector_type_ != foreground_collector_type_) { 201 VLOG(heap) << "Disabling background compaction for non zygote"; 202 background_collector_type_ = foreground_collector_type_; 203 } 204 } 205 ChangeCollector(desired_collector_type_); 206 live_bitmap_.reset(new accounting::HeapBitmap(this)); 207 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 208 // Requested begin for the alloc space, to follow the mapped image and oat files 209 byte* requested_alloc_space_begin = nullptr; 210 if (!image_file_name.empty()) { 211 std::string error_msg; 212 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 213 image_instruction_set, 214 &error_msg); 215 if (image_space != nullptr) { 216 AddSpace(image_space); 217 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 218 // isn't going to get in the middle 219 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 220 CHECK_GT(oat_file_end_addr, image_space->End()); 221 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 222 } else { 223 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 224 << "Attempting to fall back to imageless running. Error was: " << error_msg; 225 } 226 } 227 /* 228 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 229 +- nonmoving space (non_moving_space_capacity)+- 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 231 +-????????????????????????????????????????????+- 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 233 +-main alloc space / bump space 1 (capacity_) +- 234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 235 +-????????????????????????????????????????????+- 236 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 237 +-main alloc space2 / bump space 2 (capacity_)+- 238 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 239 */ 240 bool support_homogeneous_space_compaction = 241 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 242 use_homogeneous_space_compaction_for_oom; 243 // We may use the same space the main space for the non moving space if we don't need to compact 244 // from the main space. 245 // This is not the case if we support homogeneous compaction or have a moving background 246 // collector type. 247 bool separate_non_moving_space = is_zygote || 248 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 249 IsMovingGc(background_collector_type_); 250 if (foreground_collector_type == kCollectorTypeGSS) { 251 separate_non_moving_space = false; 252 } 253 std::unique_ptr<MemMap> main_mem_map_1; 254 std::unique_ptr<MemMap> main_mem_map_2; 255 byte* request_begin = requested_alloc_space_begin; 256 if (request_begin != nullptr && separate_non_moving_space) { 257 request_begin += non_moving_space_capacity; 258 } 259 std::string error_str; 260 std::unique_ptr<MemMap> non_moving_space_mem_map; 261 if (separate_non_moving_space) { 262 // Reserve the non moving mem map before the other two since it needs to be at a specific 263 // address. 264 non_moving_space_mem_map.reset( 265 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 266 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 267 CHECK(non_moving_space_mem_map != nullptr) << error_str; 268 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 269 request_begin = reinterpret_cast<byte*>(300 * MB); 270 } 271 // Attempt to create 2 mem maps at or after the requested begin. 272 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 273 PROT_READ | PROT_WRITE, &error_str)); 274 CHECK(main_mem_map_1.get() != nullptr) << error_str; 275 if (support_homogeneous_space_compaction || 276 background_collector_type_ == kCollectorTypeSS || 277 foreground_collector_type_ == kCollectorTypeSS) { 278 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 279 capacity_, PROT_READ | PROT_WRITE, 280 &error_str)); 281 CHECK(main_mem_map_2.get() != nullptr) << error_str; 282 } 283 // Create the non moving space first so that bitmaps don't take up the address range. 284 if (separate_non_moving_space) { 285 // Non moving space is always dlmalloc since we currently don't have support for multiple 286 // active rosalloc spaces. 287 const size_t size = non_moving_space_mem_map->Size(); 288 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 289 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 290 initial_size, size, size, false); 291 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 292 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 293 << requested_alloc_space_begin; 294 AddSpace(non_moving_space_); 295 } 296 // Create other spaces based on whether or not we have a moving GC. 297 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 298 // Create bump pointer spaces. 299 // We only to create the bump pointer if the foreground collector is a compacting GC. 300 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 301 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 302 main_mem_map_1.release()); 303 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 304 AddSpace(bump_pointer_space_); 305 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 306 main_mem_map_2.release()); 307 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 308 AddSpace(temp_space_); 309 CHECK(separate_non_moving_space); 310 } else { 311 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 312 CHECK(main_space_ != nullptr); 313 AddSpace(main_space_); 314 if (!separate_non_moving_space) { 315 non_moving_space_ = main_space_; 316 CHECK(!non_moving_space_->CanMoveObjects()); 317 } 318 if (foreground_collector_type_ == kCollectorTypeGSS) { 319 CHECK_EQ(foreground_collector_type_, background_collector_type_); 320 // Create bump pointer spaces instead of a backup space. 321 main_mem_map_2.release(); 322 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 323 kGSSBumpPointerSpaceCapacity, nullptr); 324 CHECK(bump_pointer_space_ != nullptr); 325 AddSpace(bump_pointer_space_); 326 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 327 kGSSBumpPointerSpaceCapacity, nullptr); 328 CHECK(temp_space_ != nullptr); 329 AddSpace(temp_space_); 330 } else if (main_mem_map_2.get() != nullptr) { 331 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 332 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 333 growth_limit_, capacity_, name, true)); 334 CHECK(main_space_backup_.get() != nullptr); 335 // Add the space so its accounted for in the heap_begin and heap_end. 336 AddSpace(main_space_backup_.get()); 337 } 338 } 339 CHECK(non_moving_space_ != nullptr); 340 CHECK(!non_moving_space_->CanMoveObjects()); 341 // Allocate the large object space. 342 if (kUseFreeListSpaceForLOS) { 343 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 344 } else { 345 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 346 } 347 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 348 AddSpace(large_object_space_); 349 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 350 CHECK(!continuous_spaces_.empty()); 351 // Relies on the spaces being sorted. 352 byte* heap_begin = continuous_spaces_.front()->Begin(); 353 byte* heap_end = continuous_spaces_.back()->Limit(); 354 size_t heap_capacity = heap_end - heap_begin; 355 // Remove the main backup space since it slows down the GC to have unused extra spaces. 356 if (main_space_backup_.get() != nullptr) { 357 RemoveSpace(main_space_backup_.get()); 358 } 359 // Allocate the card table. 360 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 361 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 362 // Card cache for now since it makes it easier for us to update the references to the copying 363 // spaces. 364 accounting::ModUnionTable* mod_union_table = 365 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 366 GetImageSpace()); 367 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 368 AddModUnionTable(mod_union_table); 369 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 370 accounting::RememberedSet* non_moving_space_rem_set = 371 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 372 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 373 AddRememberedSet(non_moving_space_rem_set); 374 } 375 // TODO: Count objects in the image space here? 376 num_bytes_allocated_.StoreRelaxed(0); 377 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 378 kDefaultMarkStackSize)); 379 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 380 allocation_stack_.reset(accounting::ObjectStack::Create( 381 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 382 live_stack_.reset(accounting::ObjectStack::Create( 383 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 384 // It's still too early to take a lock because there are no threads yet, but we can create locks 385 // now. We don't create it earlier to make it clear that you can't use locks during heap 386 // initialization. 387 gc_complete_lock_ = new Mutex("GC complete lock"); 388 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 389 *gc_complete_lock_)); 390 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 391 last_gc_size_ = GetBytesAllocated(); 392 if (ignore_max_footprint_) { 393 SetIdealFootprint(std::numeric_limits<size_t>::max()); 394 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 395 } 396 CHECK_NE(max_allowed_footprint_, 0U); 397 // Create our garbage collectors. 398 for (size_t i = 0; i < 2; ++i) { 399 const bool concurrent = i != 0; 400 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 401 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 402 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 403 } 404 if (kMovingCollector) { 405 // TODO: Clean this up. 406 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 407 semi_space_collector_ = new collector::SemiSpace(this, generational, 408 generational ? "generational" : ""); 409 garbage_collectors_.push_back(semi_space_collector_); 410 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 411 garbage_collectors_.push_back(concurrent_copying_collector_); 412 mark_compact_collector_ = new collector::MarkCompact(this); 413 garbage_collectors_.push_back(mark_compact_collector_); 414 } 415 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr) { 416 // Check that there's no gap between the image space and the non moving space so that the 417 // immune region won't break (eg. due to a large object allocated in the gap). 418 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 419 non_moving_space_->GetMemMap()); 420 if (!no_gap) { 421 MemMap::DumpMaps(LOG(ERROR)); 422 LOG(FATAL) << "There's a gap between the image space and the main space"; 423 } 424 } 425 if (running_on_valgrind_) { 426 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 427 } 428 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 429 LOG(INFO) << "Heap() exiting"; 430 } 431 } 432 433 MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 434 int prot_flags, std::string* out_error_str) { 435 while (true) { 436 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 437 PROT_READ | PROT_WRITE, true, out_error_str); 438 if (map != nullptr || request_begin == nullptr) { 439 return map; 440 } 441 // Retry a second time with no specified request begin. 442 request_begin = nullptr; 443 } 444 return nullptr; 445 } 446 447 space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 448 size_t growth_limit, size_t capacity, 449 const char* name, bool can_move_objects) { 450 space::MallocSpace* malloc_space = nullptr; 451 if (kUseRosAlloc) { 452 // Create rosalloc space. 453 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 454 initial_size, growth_limit, capacity, 455 low_memory_mode_, can_move_objects); 456 } else { 457 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 458 initial_size, growth_limit, capacity, 459 can_move_objects); 460 } 461 if (collector::SemiSpace::kUseRememberedSet) { 462 accounting::RememberedSet* rem_set = 463 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 464 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 465 AddRememberedSet(rem_set); 466 } 467 CHECK(malloc_space != nullptr) << "Failed to create " << name; 468 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 469 return malloc_space; 470 } 471 472 void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 473 size_t capacity) { 474 // Is background compaction is enabled? 475 bool can_move_objects = IsMovingGc(background_collector_type_) != 476 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 477 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 478 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 479 // from the main space to the zygote space. If background compaction is enabled, always pass in 480 // that we can move objets. 481 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 482 // After the zygote we want this to be false if we don't have background compaction enabled so 483 // that getting primitive array elements is faster. 484 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 485 can_move_objects = !have_zygote_space_ && foreground_collector_type_ != kCollectorTypeGSS; 486 } 487 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 488 RemoveRememberedSet(main_space_); 489 } 490 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 491 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 492 can_move_objects); 493 SetSpaceAsDefault(main_space_); 494 VLOG(heap) << "Created main space " << main_space_; 495 } 496 497 void Heap::ChangeAllocator(AllocatorType allocator) { 498 if (current_allocator_ != allocator) { 499 // These two allocators are only used internally and don't have any entrypoints. 500 CHECK_NE(allocator, kAllocatorTypeLOS); 501 CHECK_NE(allocator, kAllocatorTypeNonMoving); 502 current_allocator_ = allocator; 503 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 504 SetQuickAllocEntryPointsAllocator(current_allocator_); 505 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 506 } 507 } 508 509 void Heap::DisableMovingGc() { 510 if (IsMovingGc(foreground_collector_type_)) { 511 foreground_collector_type_ = kCollectorTypeCMS; 512 } 513 if (IsMovingGc(background_collector_type_)) { 514 background_collector_type_ = foreground_collector_type_; 515 } 516 TransitionCollector(foreground_collector_type_); 517 ThreadList* tl = Runtime::Current()->GetThreadList(); 518 Thread* self = Thread::Current(); 519 ScopedThreadStateChange tsc(self, kSuspended); 520 tl->SuspendAll(); 521 // Something may have caused the transition to fail. 522 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 523 CHECK(main_space_ != nullptr); 524 // The allocation stack may have non movable objects in it. We need to flush it since the GC 525 // can't only handle marking allocation stack objects of one non moving space and one main 526 // space. 527 { 528 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 529 FlushAllocStack(); 530 } 531 main_space_->DisableMovingObjects(); 532 non_moving_space_ = main_space_; 533 CHECK(!non_moving_space_->CanMoveObjects()); 534 } 535 tl->ResumeAll(); 536 } 537 538 std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 539 if (!IsValidContinuousSpaceObjectAddress(klass)) { 540 return StringPrintf("<non heap address klass %p>", klass); 541 } 542 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 543 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 544 std::string result("["); 545 result += SafeGetClassDescriptor(component_type); 546 return result; 547 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 548 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 549 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 550 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 551 } else { 552 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 553 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 554 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 555 } 556 const DexFile* dex_file = dex_cache->GetDexFile(); 557 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 558 if (class_def_idx == DexFile::kDexNoIndex16) { 559 return "<class def not found>"; 560 } 561 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 562 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 563 return dex_file->GetTypeDescriptor(type_id); 564 } 565 } 566 567 std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 568 if (obj == nullptr) { 569 return "null"; 570 } 571 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 572 if (klass == nullptr) { 573 return "(class=null)"; 574 } 575 std::string result(SafeGetClassDescriptor(klass)); 576 if (obj->IsClass()) { 577 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 578 } 579 return result; 580 } 581 582 void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 583 if (obj == nullptr) { 584 stream << "(obj=null)"; 585 return; 586 } 587 if (IsAligned<kObjectAlignment>(obj)) { 588 space::Space* space = nullptr; 589 // Don't use find space since it only finds spaces which actually contain objects instead of 590 // spaces which may contain objects (e.g. cleared bump pointer spaces). 591 for (const auto& cur_space : continuous_spaces_) { 592 if (cur_space->HasAddress(obj)) { 593 space = cur_space; 594 break; 595 } 596 } 597 // Unprotect all the spaces. 598 for (const auto& space : continuous_spaces_) { 599 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 600 } 601 stream << "Object " << obj; 602 if (space != nullptr) { 603 stream << " in space " << *space; 604 } 605 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 606 stream << "\nclass=" << klass; 607 if (klass != nullptr) { 608 stream << " type= " << SafePrettyTypeOf(obj); 609 } 610 // Re-protect the address we faulted on. 611 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 612 } 613 } 614 615 bool Heap::IsCompilingBoot() const { 616 if (!Runtime::Current()->IsCompiler()) { 617 return false; 618 } 619 for (const auto& space : continuous_spaces_) { 620 if (space->IsImageSpace() || space->IsZygoteSpace()) { 621 return false; 622 } 623 } 624 return true; 625 } 626 627 bool Heap::HasImageSpace() const { 628 for (const auto& space : continuous_spaces_) { 629 if (space->IsImageSpace()) { 630 return true; 631 } 632 } 633 return false; 634 } 635 636 void Heap::IncrementDisableMovingGC(Thread* self) { 637 // Need to do this holding the lock to prevent races where the GC is about to run / running when 638 // we attempt to disable it. 639 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 640 MutexLock mu(self, *gc_complete_lock_); 641 ++disable_moving_gc_count_; 642 if (IsMovingGc(collector_type_running_)) { 643 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 644 } 645 } 646 647 void Heap::DecrementDisableMovingGC(Thread* self) { 648 MutexLock mu(self, *gc_complete_lock_); 649 CHECK_GE(disable_moving_gc_count_, 0U); 650 --disable_moving_gc_count_; 651 } 652 653 void Heap::UpdateProcessState(ProcessState process_state) { 654 if (process_state_ != process_state) { 655 process_state_ = process_state; 656 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 657 // Start at index 1 to avoid "is always false" warning. 658 // Have iteration 1 always transition the collector. 659 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 660 ? foreground_collector_type_ : background_collector_type_); 661 usleep(kCollectorTransitionStressWait); 662 } 663 if (process_state_ == kProcessStateJankPerceptible) { 664 // Transition back to foreground right away to prevent jank. 665 RequestCollectorTransition(foreground_collector_type_, 0); 666 } else { 667 // Don't delay for debug builds since we may want to stress test the GC. 668 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 669 // special handling which does a homogenous space compaction once but then doesn't transition 670 // the collector. 671 RequestCollectorTransition(background_collector_type_, 672 kIsDebugBuild ? 0 : kCollectorTransitionWait); 673 } 674 } 675 } 676 677 void Heap::CreateThreadPool() { 678 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 679 if (num_threads != 0) { 680 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 681 } 682 } 683 684 void Heap::VisitObjects(ObjectCallback callback, void* arg) { 685 Thread* self = Thread::Current(); 686 // GCs can move objects, so don't allow this. 687 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 688 if (bump_pointer_space_ != nullptr) { 689 // Visit objects in bump pointer space. 690 bump_pointer_space_->Walk(callback, arg); 691 } 692 // TODO: Switch to standard begin and end to use ranged a based loop. 693 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 694 it < end; ++it) { 695 mirror::Object* obj = *it; 696 if (obj != nullptr && obj->GetClass() != nullptr) { 697 // Avoid the race condition caused by the object not yet being written into the allocation 698 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 699 // there can be nulls on the allocation stack. 700 callback(obj, arg); 701 } 702 } 703 GetLiveBitmap()->Walk(callback, arg); 704 self->EndAssertNoThreadSuspension(old_cause); 705 } 706 707 void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 708 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 709 space::ContinuousSpace* space2 = non_moving_space_; 710 // TODO: Generalize this to n bitmaps? 711 CHECK(space1 != nullptr); 712 CHECK(space2 != nullptr); 713 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 714 large_object_space_->GetLiveBitmap(), stack); 715 } 716 717 void Heap::DeleteThreadPool() { 718 thread_pool_.reset(nullptr); 719 } 720 721 void Heap::AddSpace(space::Space* space) { 722 CHECK(space != nullptr); 723 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 724 if (space->IsContinuousSpace()) { 725 DCHECK(!space->IsDiscontinuousSpace()); 726 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 727 // Continuous spaces don't necessarily have bitmaps. 728 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 729 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 730 if (live_bitmap != nullptr) { 731 CHECK(mark_bitmap != nullptr); 732 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 733 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 734 } 735 continuous_spaces_.push_back(continuous_space); 736 // Ensure that spaces remain sorted in increasing order of start address. 737 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 738 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 739 return a->Begin() < b->Begin(); 740 }); 741 } else { 742 CHECK(space->IsDiscontinuousSpace()); 743 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 744 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 745 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 746 discontinuous_spaces_.push_back(discontinuous_space); 747 } 748 if (space->IsAllocSpace()) { 749 alloc_spaces_.push_back(space->AsAllocSpace()); 750 } 751 } 752 753 void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 754 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 755 if (continuous_space->IsDlMallocSpace()) { 756 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 757 } else if (continuous_space->IsRosAllocSpace()) { 758 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 759 } 760 } 761 762 void Heap::RemoveSpace(space::Space* space) { 763 DCHECK(space != nullptr); 764 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 765 if (space->IsContinuousSpace()) { 766 DCHECK(!space->IsDiscontinuousSpace()); 767 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 768 // Continuous spaces don't necessarily have bitmaps. 769 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 770 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 771 if (live_bitmap != nullptr) { 772 DCHECK(mark_bitmap != nullptr); 773 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 774 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 775 } 776 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 777 DCHECK(it != continuous_spaces_.end()); 778 continuous_spaces_.erase(it); 779 } else { 780 DCHECK(space->IsDiscontinuousSpace()); 781 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 782 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 783 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 784 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 785 discontinuous_space); 786 DCHECK(it != discontinuous_spaces_.end()); 787 discontinuous_spaces_.erase(it); 788 } 789 if (space->IsAllocSpace()) { 790 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 791 DCHECK(it != alloc_spaces_.end()); 792 alloc_spaces_.erase(it); 793 } 794 } 795 796 void Heap::DumpGcPerformanceInfo(std::ostream& os) { 797 // Dump cumulative timings. 798 os << "Dumping cumulative Gc timings\n"; 799 uint64_t total_duration = 0; 800 // Dump cumulative loggers for each GC type. 801 uint64_t total_paused_time = 0; 802 for (auto& collector : garbage_collectors_) { 803 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 804 const size_t iterations = logger.GetIterations(); 805 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 806 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 807 os << ConstDumpable<CumulativeLogger>(logger); 808 const uint64_t total_ns = logger.GetTotalNs(); 809 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 810 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 811 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 812 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 813 Histogram<uint64_t>::CumulativeData cumulative_data; 814 pause_histogram.CreateHistogram(&cumulative_data); 815 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 816 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 817 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 818 << collector->GetName() << " freed: " << freed_objects 819 << " objects with total size " << PrettySize(freed_bytes) << "\n" 820 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 821 << PrettySize(freed_bytes / seconds) << "/s\n"; 822 total_duration += total_ns; 823 total_paused_time += total_pause_ns; 824 } 825 collector->ResetMeasurements(); 826 } 827 uint64_t allocation_time = 828 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 829 if (total_duration != 0) { 830 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 831 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 832 os << "Mean GC size throughput: " 833 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 834 os << "Mean GC object throughput: " 835 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 836 } 837 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 838 os << "Total number of allocations " << total_objects_allocated << "\n"; 839 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 840 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 841 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 842 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 843 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 844 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 845 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 846 if (kMeasureAllocationTime) { 847 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 848 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 849 << "\n"; 850 } 851 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 852 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 853 BaseMutex::DumpAll(os); 854 } 855 856 Heap::~Heap() { 857 VLOG(heap) << "Starting ~Heap()"; 858 STLDeleteElements(&garbage_collectors_); 859 // If we don't reset then the mark stack complains in its destructor. 860 allocation_stack_->Reset(); 861 live_stack_->Reset(); 862 STLDeleteValues(&mod_union_tables_); 863 STLDeleteValues(&remembered_sets_); 864 STLDeleteElements(&continuous_spaces_); 865 STLDeleteElements(&discontinuous_spaces_); 866 delete gc_complete_lock_; 867 delete heap_trim_request_lock_; 868 VLOG(heap) << "Finished ~Heap()"; 869 } 870 871 space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 872 bool fail_ok) const { 873 for (const auto& space : continuous_spaces_) { 874 if (space->Contains(obj)) { 875 return space; 876 } 877 } 878 if (!fail_ok) { 879 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 880 } 881 return NULL; 882 } 883 884 space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 885 bool fail_ok) const { 886 for (const auto& space : discontinuous_spaces_) { 887 if (space->Contains(obj)) { 888 return space; 889 } 890 } 891 if (!fail_ok) { 892 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 893 } 894 return NULL; 895 } 896 897 space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 898 space::Space* result = FindContinuousSpaceFromObject(obj, true); 899 if (result != NULL) { 900 return result; 901 } 902 return FindDiscontinuousSpaceFromObject(obj, true); 903 } 904 905 space::ImageSpace* Heap::GetImageSpace() const { 906 for (const auto& space : continuous_spaces_) { 907 if (space->IsImageSpace()) { 908 return space->AsImageSpace(); 909 } 910 } 911 return NULL; 912 } 913 914 void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 915 std::ostringstream oss; 916 size_t total_bytes_free = GetFreeMemory(); 917 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 918 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 919 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 920 if (total_bytes_free >= byte_count) { 921 space::AllocSpace* space = nullptr; 922 if (allocator_type == kAllocatorTypeNonMoving) { 923 space = non_moving_space_; 924 } else if (allocator_type == kAllocatorTypeRosAlloc || 925 allocator_type == kAllocatorTypeDlMalloc) { 926 space = main_space_; 927 } else if (allocator_type == kAllocatorTypeBumpPointer || 928 allocator_type == kAllocatorTypeTLAB) { 929 space = bump_pointer_space_; 930 } 931 if (space != nullptr) { 932 space->LogFragmentationAllocFailure(oss, byte_count); 933 } 934 } 935 self->ThrowOutOfMemoryError(oss.str().c_str()); 936 } 937 938 void Heap::DoPendingTransitionOrTrim() { 939 Thread* self = Thread::Current(); 940 CollectorType desired_collector_type; 941 // Wait until we reach the desired transition time. 942 while (true) { 943 uint64_t wait_time; 944 { 945 MutexLock mu(self, *heap_trim_request_lock_); 946 desired_collector_type = desired_collector_type_; 947 uint64_t current_time = NanoTime(); 948 if (current_time >= heap_transition_or_trim_target_time_) { 949 break; 950 } 951 wait_time = heap_transition_or_trim_target_time_ - current_time; 952 } 953 ScopedThreadStateChange tsc(self, kSleeping); 954 usleep(wait_time / 1000); // Usleep takes microseconds. 955 } 956 // Launch homogeneous space compaction if it is desired. 957 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 958 if (!CareAboutPauseTimes()) { 959 PerformHomogeneousSpaceCompact(); 960 } 961 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 962 desired_collector_type = collector_type_; 963 return; 964 } 965 // Transition the collector if the desired collector type is not the same as the current 966 // collector type. 967 TransitionCollector(desired_collector_type); 968 if (!CareAboutPauseTimes()) { 969 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 970 // about pauses. 971 Runtime* runtime = Runtime::Current(); 972 runtime->GetThreadList()->SuspendAll(); 973 uint64_t start_time = NanoTime(); 974 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 975 VLOG(heap) << "Deflating " << count << " monitors took " 976 << PrettyDuration(NanoTime() - start_time); 977 runtime->GetThreadList()->ResumeAll(); 978 } 979 // Do a heap trim if it is needed. 980 Trim(); 981 } 982 983 void Heap::Trim() { 984 Thread* self = Thread::Current(); 985 { 986 MutexLock mu(self, *heap_trim_request_lock_); 987 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 988 return; 989 } 990 last_trim_time_ = NanoTime(); 991 heap_trim_request_pending_ = false; 992 } 993 { 994 // Need to do this before acquiring the locks since we don't want to get suspended while 995 // holding any locks. 996 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 997 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 998 // trimming. 999 MutexLock mu(self, *gc_complete_lock_); 1000 // Ensure there is only one GC at a time. 1001 WaitForGcToCompleteLocked(kGcCauseTrim, self); 1002 collector_type_running_ = kCollectorTypeHeapTrim; 1003 } 1004 uint64_t start_ns = NanoTime(); 1005 // Trim the managed spaces. 1006 uint64_t total_alloc_space_allocated = 0; 1007 uint64_t total_alloc_space_size = 0; 1008 uint64_t managed_reclaimed = 0; 1009 for (const auto& space : continuous_spaces_) { 1010 if (space->IsMallocSpace()) { 1011 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 1012 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 1013 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 1014 // for a long period of time. 1015 managed_reclaimed += malloc_space->Trim(); 1016 } 1017 total_alloc_space_size += malloc_space->Size(); 1018 } 1019 } 1020 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 1021 if (bump_pointer_space_ != nullptr) { 1022 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1023 } 1024 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1025 static_cast<float>(total_alloc_space_size); 1026 uint64_t gc_heap_end_ns = NanoTime(); 1027 // We never move things in the native heap, so we can finish the GC at this point. 1028 FinishGC(self, collector::kGcTypeNone); 1029 size_t native_reclaimed = 0; 1030 // Only trim the native heap if we don't care about pauses. 1031 if (!CareAboutPauseTimes()) { 1032 #if defined(USE_DLMALLOC) 1033 // Trim the native heap. 1034 dlmalloc_trim(0); 1035 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1036 #elif defined(USE_JEMALLOC) 1037 // Jemalloc does it's own internal trimming. 1038 #else 1039 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1040 #endif 1041 } 1042 uint64_t end_ns = NanoTime(); 1043 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1044 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1045 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1046 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1047 << "%."; 1048 } 1049 1050 bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1051 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1052 // taking the lock. 1053 if (obj == nullptr) { 1054 return true; 1055 } 1056 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1057 } 1058 1059 bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1060 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1061 } 1062 1063 bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1064 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1065 return false; 1066 } 1067 for (const auto& space : continuous_spaces_) { 1068 if (space->HasAddress(obj)) { 1069 return true; 1070 } 1071 } 1072 return false; 1073 } 1074 1075 bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1076 bool search_live_stack, bool sorted) { 1077 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1078 return false; 1079 } 1080 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1081 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1082 if (obj == klass) { 1083 // This case happens for java.lang.Class. 1084 return true; 1085 } 1086 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1087 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1088 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1089 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1090 return temp_space_->Contains(obj); 1091 } 1092 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1093 space::DiscontinuousSpace* d_space = nullptr; 1094 if (c_space != nullptr) { 1095 if (c_space->GetLiveBitmap()->Test(obj)) { 1096 return true; 1097 } 1098 } else { 1099 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1100 if (d_space != nullptr) { 1101 if (d_space->GetLiveBitmap()->Test(obj)) { 1102 return true; 1103 } 1104 } 1105 } 1106 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1107 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1108 if (i > 0) { 1109 NanoSleep(MsToNs(10)); 1110 } 1111 if (search_allocation_stack) { 1112 if (sorted) { 1113 if (allocation_stack_->ContainsSorted(obj)) { 1114 return true; 1115 } 1116 } else if (allocation_stack_->Contains(obj)) { 1117 return true; 1118 } 1119 } 1120 1121 if (search_live_stack) { 1122 if (sorted) { 1123 if (live_stack_->ContainsSorted(obj)) { 1124 return true; 1125 } 1126 } else if (live_stack_->Contains(obj)) { 1127 return true; 1128 } 1129 } 1130 } 1131 // We need to check the bitmaps again since there is a race where we mark something as live and 1132 // then clear the stack containing it. 1133 if (c_space != nullptr) { 1134 if (c_space->GetLiveBitmap()->Test(obj)) { 1135 return true; 1136 } 1137 } else { 1138 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1139 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1140 return true; 1141 } 1142 } 1143 return false; 1144 } 1145 1146 std::string Heap::DumpSpaces() const { 1147 std::ostringstream oss; 1148 DumpSpaces(oss); 1149 return oss.str(); 1150 } 1151 1152 void Heap::DumpSpaces(std::ostream& stream) const { 1153 for (const auto& space : continuous_spaces_) { 1154 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1155 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1156 stream << space << " " << *space << "\n"; 1157 if (live_bitmap != nullptr) { 1158 stream << live_bitmap << " " << *live_bitmap << "\n"; 1159 } 1160 if (mark_bitmap != nullptr) { 1161 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1162 } 1163 } 1164 for (const auto& space : discontinuous_spaces_) { 1165 stream << space << " " << *space << "\n"; 1166 } 1167 } 1168 1169 void Heap::VerifyObjectBody(mirror::Object* obj) { 1170 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1171 return; 1172 } 1173 1174 // Ignore early dawn of the universe verifications. 1175 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1176 return; 1177 } 1178 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1179 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1180 CHECK(c != nullptr) << "Null class in object " << obj; 1181 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1182 CHECK(VerifyClassClass(c)); 1183 1184 if (verify_object_mode_ > kVerifyObjectModeFast) { 1185 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1186 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1187 } 1188 } 1189 1190 void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1191 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1192 } 1193 1194 void Heap::VerifyHeap() { 1195 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1196 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1197 } 1198 1199 void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1200 // Use signed comparison since freed bytes can be negative when background compaction foreground 1201 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1202 // free list backed space typically increasing memory footprint due to padding and binning. 1203 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1204 // Note: This relies on 2s complement for handling negative freed_bytes. 1205 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1206 if (Runtime::Current()->HasStatsEnabled()) { 1207 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1208 thread_stats->freed_objects += freed_objects; 1209 thread_stats->freed_bytes += freed_bytes; 1210 // TODO: Do this concurrently. 1211 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1212 global_stats->freed_objects += freed_objects; 1213 global_stats->freed_bytes += freed_bytes; 1214 } 1215 } 1216 1217 space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1218 for (const auto& space : continuous_spaces_) { 1219 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1220 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1221 return space->AsContinuousSpace()->AsRosAllocSpace(); 1222 } 1223 } 1224 } 1225 return nullptr; 1226 } 1227 1228 mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1229 size_t alloc_size, size_t* bytes_allocated, 1230 size_t* usable_size, 1231 mirror::Class** klass) { 1232 bool was_default_allocator = allocator == GetCurrentAllocator(); 1233 // Make sure there is no pending exception since we may need to throw an OOME. 1234 self->AssertNoPendingException(); 1235 DCHECK(klass != nullptr); 1236 StackHandleScope<1> hs(self); 1237 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1238 klass = nullptr; // Invalidate for safety. 1239 // The allocation failed. If the GC is running, block until it completes, and then retry the 1240 // allocation. 1241 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1242 if (last_gc != collector::kGcTypeNone) { 1243 // If we were the default allocator but the allocator changed while we were suspended, 1244 // abort the allocation. 1245 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1246 return nullptr; 1247 } 1248 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1249 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1250 usable_size); 1251 if (ptr != nullptr) { 1252 return ptr; 1253 } 1254 } 1255 1256 collector::GcType tried_type = next_gc_type_; 1257 const bool gc_ran = 1258 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1259 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1260 return nullptr; 1261 } 1262 if (gc_ran) { 1263 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1264 usable_size); 1265 if (ptr != nullptr) { 1266 return ptr; 1267 } 1268 } 1269 1270 // Loop through our different Gc types and try to Gc until we get enough free memory. 1271 for (collector::GcType gc_type : gc_plan_) { 1272 if (gc_type == tried_type) { 1273 continue; 1274 } 1275 // Attempt to run the collector, if we succeed, re-try the allocation. 1276 const bool gc_ran = 1277 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1278 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1279 return nullptr; 1280 } 1281 if (gc_ran) { 1282 // Did we free sufficient memory for the allocation to succeed? 1283 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1284 usable_size); 1285 if (ptr != nullptr) { 1286 return ptr; 1287 } 1288 } 1289 } 1290 // Allocations have failed after GCs; this is an exceptional state. 1291 // Try harder, growing the heap if necessary. 1292 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1293 usable_size); 1294 if (ptr != nullptr) { 1295 return ptr; 1296 } 1297 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1298 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1299 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1300 // OOME. 1301 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1302 << " allocation"; 1303 // TODO: Run finalization, but this may cause more allocations to occur. 1304 // We don't need a WaitForGcToComplete here either. 1305 DCHECK(!gc_plan_.empty()); 1306 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1307 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1308 return nullptr; 1309 } 1310 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1311 if (ptr == nullptr) { 1312 const uint64_t current_time = NanoTime(); 1313 switch (allocator) { 1314 case kAllocatorTypeRosAlloc: 1315 // Fall-through. 1316 case kAllocatorTypeDlMalloc: { 1317 if (use_homogeneous_space_compaction_for_oom_ && 1318 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1319 min_interval_homogeneous_space_compaction_by_oom_) { 1320 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1321 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1322 switch (result) { 1323 case HomogeneousSpaceCompactResult::kSuccess: 1324 // If the allocation succeeded, we delayed an oom. 1325 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1326 usable_size); 1327 if (ptr != nullptr) { 1328 count_delayed_oom_++; 1329 } 1330 break; 1331 case HomogeneousSpaceCompactResult::kErrorReject: 1332 // Reject due to disabled moving GC. 1333 break; 1334 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1335 // Throw OOM by default. 1336 break; 1337 default: { 1338 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1339 << static_cast<size_t>(result); 1340 } 1341 } 1342 // Always print that we ran homogeneous space compation since this can cause jank. 1343 VLOG(heap) << "Ran heap homogeneous space compaction, " 1344 << " requested defragmentation " 1345 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1346 << " performed defragmentation " 1347 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1348 << " ignored homogeneous space compaction " 1349 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1350 << " delayed count = " 1351 << count_delayed_oom_.LoadSequentiallyConsistent(); 1352 } 1353 break; 1354 } 1355 case kAllocatorTypeNonMoving: { 1356 // Try to transition the heap if the allocation failure was due to the space being full. 1357 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1358 // If we aren't out of memory then the OOM was probably from the non moving space being 1359 // full. Attempt to disable compaction and turn the main space into a non moving space. 1360 DisableMovingGc(); 1361 // If we are still a moving GC then something must have caused the transition to fail. 1362 if (IsMovingGc(collector_type_)) { 1363 MutexLock mu(self, *gc_complete_lock_); 1364 // If we couldn't disable moving GC, just throw OOME and return null. 1365 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1366 << disable_moving_gc_count_; 1367 } else { 1368 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1369 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1370 usable_size); 1371 } 1372 } 1373 break; 1374 } 1375 default: { 1376 // Do nothing for others allocators. 1377 } 1378 } 1379 } 1380 // If the allocation hasn't succeeded by this point, throw an OOM error. 1381 if (ptr == nullptr) { 1382 ThrowOutOfMemoryError(self, alloc_size, allocator); 1383 } 1384 return ptr; 1385 } 1386 1387 void Heap::SetTargetHeapUtilization(float target) { 1388 DCHECK_GT(target, 0.0f); // asserted in Java code 1389 DCHECK_LT(target, 1.0f); 1390 target_utilization_ = target; 1391 } 1392 1393 size_t Heap::GetObjectsAllocated() const { 1394 size_t total = 0; 1395 for (space::AllocSpace* space : alloc_spaces_) { 1396 total += space->GetObjectsAllocated(); 1397 } 1398 return total; 1399 } 1400 1401 uint64_t Heap::GetObjectsAllocatedEver() const { 1402 return GetObjectsFreedEver() + GetObjectsAllocated(); 1403 } 1404 1405 uint64_t Heap::GetBytesAllocatedEver() const { 1406 return GetBytesFreedEver() + GetBytesAllocated(); 1407 } 1408 1409 class InstanceCounter { 1410 public: 1411 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1412 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1413 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1414 } 1415 static void Callback(mirror::Object* obj, void* arg) 1416 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1417 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1418 mirror::Class* instance_class = obj->GetClass(); 1419 CHECK(instance_class != nullptr); 1420 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1421 if (instance_counter->use_is_assignable_from_) { 1422 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1423 ++instance_counter->counts_[i]; 1424 } 1425 } else if (instance_class == instance_counter->classes_[i]) { 1426 ++instance_counter->counts_[i]; 1427 } 1428 } 1429 } 1430 1431 private: 1432 const std::vector<mirror::Class*>& classes_; 1433 bool use_is_assignable_from_; 1434 uint64_t* const counts_; 1435 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1436 }; 1437 1438 void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1439 uint64_t* counts) { 1440 // Can't do any GC in this function since this may move classes. 1441 Thread* self = Thread::Current(); 1442 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1443 InstanceCounter counter(classes, use_is_assignable_from, counts); 1444 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1445 VisitObjects(InstanceCounter::Callback, &counter); 1446 self->EndAssertNoThreadSuspension(old_cause); 1447 } 1448 1449 class InstanceCollector { 1450 public: 1451 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1452 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1453 : class_(c), max_count_(max_count), instances_(instances) { 1454 } 1455 static void Callback(mirror::Object* obj, void* arg) 1456 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1457 DCHECK(arg != nullptr); 1458 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1459 mirror::Class* instance_class = obj->GetClass(); 1460 if (instance_class == instance_collector->class_) { 1461 if (instance_collector->max_count_ == 0 || 1462 instance_collector->instances_.size() < instance_collector->max_count_) { 1463 instance_collector->instances_.push_back(obj); 1464 } 1465 } 1466 } 1467 1468 private: 1469 mirror::Class* class_; 1470 uint32_t max_count_; 1471 std::vector<mirror::Object*>& instances_; 1472 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1473 }; 1474 1475 void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1476 std::vector<mirror::Object*>& instances) { 1477 // Can't do any GC in this function since this may move classes. 1478 Thread* self = Thread::Current(); 1479 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1480 InstanceCollector collector(c, max_count, instances); 1481 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1482 VisitObjects(&InstanceCollector::Callback, &collector); 1483 self->EndAssertNoThreadSuspension(old_cause); 1484 } 1485 1486 class ReferringObjectsFinder { 1487 public: 1488 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1489 std::vector<mirror::Object*>& referring_objects) 1490 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1491 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1492 } 1493 1494 static void Callback(mirror::Object* obj, void* arg) 1495 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1496 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1497 } 1498 1499 // For bitmap Visit. 1500 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1501 // annotalysis on visitors. 1502 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1503 o->VisitReferences<true>(*this, VoidFunctor()); 1504 } 1505 1506 // For Object::VisitReferences. 1507 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1508 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1509 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1510 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1511 referring_objects_.push_back(obj); 1512 } 1513 } 1514 1515 private: 1516 mirror::Object* object_; 1517 uint32_t max_count_; 1518 std::vector<mirror::Object*>& referring_objects_; 1519 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1520 }; 1521 1522 void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1523 std::vector<mirror::Object*>& referring_objects) { 1524 // Can't do any GC in this function since this may move the object o. 1525 Thread* self = Thread::Current(); 1526 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1527 ReferringObjectsFinder finder(o, max_count, referring_objects); 1528 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1529 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1530 self->EndAssertNoThreadSuspension(old_cause); 1531 } 1532 1533 void Heap::CollectGarbage(bool clear_soft_references) { 1534 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1535 // last GC will not have necessarily been cleared. 1536 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1537 } 1538 1539 HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1540 Thread* self = Thread::Current(); 1541 // Inc requested homogeneous space compaction. 1542 count_requested_homogeneous_space_compaction_++; 1543 // Store performed homogeneous space compaction at a new request arrival. 1544 ThreadList* tl = Runtime::Current()->GetThreadList(); 1545 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1546 Locks::mutator_lock_->AssertNotHeld(self); 1547 { 1548 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1549 MutexLock mu(self, *gc_complete_lock_); 1550 // Ensure there is only one GC at a time. 1551 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1552 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1553 // is non zero. 1554 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1555 // exit. 1556 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1557 !main_space_->CanMoveObjects()) { 1558 return HomogeneousSpaceCompactResult::kErrorReject; 1559 } 1560 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1561 } 1562 if (Runtime::Current()->IsShuttingDown(self)) { 1563 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1564 // cause objects to get finalized. 1565 FinishGC(self, collector::kGcTypeNone); 1566 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1567 } 1568 // Suspend all threads. 1569 tl->SuspendAll(); 1570 uint64_t start_time = NanoTime(); 1571 // Launch compaction. 1572 space::MallocSpace* to_space = main_space_backup_.release(); 1573 space::MallocSpace* from_space = main_space_; 1574 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1575 const uint64_t space_size_before_compaction = from_space->Size(); 1576 AddSpace(to_space); 1577 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1578 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1579 from_space->GetMemMap()->Protect(PROT_READ); 1580 const uint64_t space_size_after_compaction = to_space->Size(); 1581 main_space_ = to_space; 1582 main_space_backup_.reset(from_space); 1583 RemoveSpace(from_space); 1584 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1585 // Update performed homogeneous space compaction count. 1586 count_performed_homogeneous_space_compaction_++; 1587 // Print statics log and resume all threads. 1588 uint64_t duration = NanoTime() - start_time; 1589 VLOG(heap) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1590 << PrettySize(space_size_before_compaction) << " -> " 1591 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1592 << std::fixed << static_cast<double>(space_size_after_compaction) / 1593 static_cast<double>(space_size_before_compaction); 1594 tl->ResumeAll(); 1595 // Finish GC. 1596 reference_processor_.EnqueueClearedReferences(self); 1597 GrowForUtilization(semi_space_collector_); 1598 FinishGC(self, collector::kGcTypeFull); 1599 return HomogeneousSpaceCompactResult::kSuccess; 1600 } 1601 1602 1603 void Heap::TransitionCollector(CollectorType collector_type) { 1604 if (collector_type == collector_type_) { 1605 return; 1606 } 1607 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1608 << " -> " << static_cast<int>(collector_type); 1609 uint64_t start_time = NanoTime(); 1610 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1611 Runtime* const runtime = Runtime::Current(); 1612 ThreadList* const tl = runtime->GetThreadList(); 1613 Thread* const self = Thread::Current(); 1614 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1615 Locks::mutator_lock_->AssertNotHeld(self); 1616 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1617 // compacting_gc_disable_count_, this should rarely occurs). 1618 for (;;) { 1619 { 1620 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1621 MutexLock mu(self, *gc_complete_lock_); 1622 // Ensure there is only one GC at a time. 1623 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1624 // Currently we only need a heap transition if we switch from a moving collector to a 1625 // non-moving one, or visa versa. 1626 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1627 // If someone else beat us to it and changed the collector before we could, exit. 1628 // This is safe to do before the suspend all since we set the collector_type_running_ before 1629 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1630 // then it would get blocked on WaitForGcToCompleteLocked. 1631 if (collector_type == collector_type_) { 1632 return; 1633 } 1634 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1635 if (!copying_transition || disable_moving_gc_count_ == 0) { 1636 // TODO: Not hard code in semi-space collector? 1637 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1638 break; 1639 } 1640 } 1641 usleep(1000); 1642 } 1643 if (runtime->IsShuttingDown(self)) { 1644 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1645 // cause objects to get finalized. 1646 FinishGC(self, collector::kGcTypeNone); 1647 return; 1648 } 1649 tl->SuspendAll(); 1650 switch (collector_type) { 1651 case kCollectorTypeSS: { 1652 if (!IsMovingGc(collector_type_)) { 1653 // Create the bump pointer space from the backup space. 1654 CHECK(main_space_backup_ != nullptr); 1655 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1656 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1657 // pointer space last transition it will be protected. 1658 CHECK(mem_map != nullptr); 1659 mem_map->Protect(PROT_READ | PROT_WRITE); 1660 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1661 mem_map.release()); 1662 AddSpace(bump_pointer_space_); 1663 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1664 // Use the now empty main space mem map for the bump pointer temp space. 1665 mem_map.reset(main_space_->ReleaseMemMap()); 1666 // Unset the pointers just in case. 1667 if (dlmalloc_space_ == main_space_) { 1668 dlmalloc_space_ = nullptr; 1669 } else if (rosalloc_space_ == main_space_) { 1670 rosalloc_space_ = nullptr; 1671 } 1672 // Remove the main space so that we don't try to trim it, this doens't work for debug 1673 // builds since RosAlloc attempts to read the magic number from a protected page. 1674 RemoveSpace(main_space_); 1675 RemoveRememberedSet(main_space_); 1676 delete main_space_; // Delete the space since it has been removed. 1677 main_space_ = nullptr; 1678 RemoveRememberedSet(main_space_backup_.get()); 1679 main_space_backup_.reset(nullptr); // Deletes the space. 1680 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1681 mem_map.release()); 1682 AddSpace(temp_space_); 1683 } 1684 break; 1685 } 1686 case kCollectorTypeMS: 1687 // Fall through. 1688 case kCollectorTypeCMS: { 1689 if (IsMovingGc(collector_type_)) { 1690 CHECK(temp_space_ != nullptr); 1691 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1692 RemoveSpace(temp_space_); 1693 temp_space_ = nullptr; 1694 mem_map->Protect(PROT_READ | PROT_WRITE); 1695 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1696 mem_map->Size()); 1697 mem_map.release(); 1698 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1699 AddSpace(main_space_); 1700 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1701 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1702 RemoveSpace(bump_pointer_space_); 1703 bump_pointer_space_ = nullptr; 1704 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1705 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1706 if (kIsDebugBuild && kUseRosAlloc) { 1707 mem_map->Protect(PROT_READ | PROT_WRITE); 1708 } 1709 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1710 mem_map->Size(), mem_map->Size(), 1711 name, true)); 1712 if (kIsDebugBuild && kUseRosAlloc) { 1713 mem_map->Protect(PROT_NONE); 1714 } 1715 mem_map.release(); 1716 } 1717 break; 1718 } 1719 default: { 1720 LOG(FATAL) << "Attempted to transition to invalid collector type " 1721 << static_cast<size_t>(collector_type); 1722 break; 1723 } 1724 } 1725 ChangeCollector(collector_type); 1726 tl->ResumeAll(); 1727 // Can't call into java code with all threads suspended. 1728 reference_processor_.EnqueueClearedReferences(self); 1729 uint64_t duration = NanoTime() - start_time; 1730 GrowForUtilization(semi_space_collector_); 1731 FinishGC(self, collector::kGcTypeFull); 1732 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1733 int32_t delta_allocated = before_allocated - after_allocated; 1734 std::string saved_str; 1735 if (delta_allocated >= 0) { 1736 saved_str = " saved at least " + PrettySize(delta_allocated); 1737 } else { 1738 saved_str = " expanded " + PrettySize(-delta_allocated); 1739 } 1740 VLOG(heap) << "Heap transition to " << process_state_ << " took " 1741 << PrettyDuration(duration) << saved_str; 1742 } 1743 1744 void Heap::ChangeCollector(CollectorType collector_type) { 1745 // TODO: Only do this with all mutators suspended to avoid races. 1746 if (collector_type != collector_type_) { 1747 if (collector_type == kCollectorTypeMC) { 1748 // Don't allow mark compact unless support is compiled in. 1749 CHECK(kMarkCompactSupport); 1750 } 1751 collector_type_ = collector_type; 1752 gc_plan_.clear(); 1753 switch (collector_type_) { 1754 case kCollectorTypeCC: // Fall-through. 1755 case kCollectorTypeMC: // Fall-through. 1756 case kCollectorTypeSS: // Fall-through. 1757 case kCollectorTypeGSS: { 1758 gc_plan_.push_back(collector::kGcTypeFull); 1759 if (use_tlab_) { 1760 ChangeAllocator(kAllocatorTypeTLAB); 1761 } else { 1762 ChangeAllocator(kAllocatorTypeBumpPointer); 1763 } 1764 break; 1765 } 1766 case kCollectorTypeMS: { 1767 gc_plan_.push_back(collector::kGcTypeSticky); 1768 gc_plan_.push_back(collector::kGcTypePartial); 1769 gc_plan_.push_back(collector::kGcTypeFull); 1770 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1771 break; 1772 } 1773 case kCollectorTypeCMS: { 1774 gc_plan_.push_back(collector::kGcTypeSticky); 1775 gc_plan_.push_back(collector::kGcTypePartial); 1776 gc_plan_.push_back(collector::kGcTypeFull); 1777 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1778 break; 1779 } 1780 default: { 1781 LOG(FATAL) << "Unimplemented"; 1782 } 1783 } 1784 if (IsGcConcurrent()) { 1785 concurrent_start_bytes_ = 1786 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1787 } else { 1788 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1789 } 1790 } 1791 } 1792 1793 // Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1794 class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1795 public: 1796 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1797 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1798 } 1799 1800 void BuildBins(space::ContinuousSpace* space) { 1801 bin_live_bitmap_ = space->GetLiveBitmap(); 1802 bin_mark_bitmap_ = space->GetMarkBitmap(); 1803 BinContext context; 1804 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1805 context.collector_ = this; 1806 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1807 // Note: This requires traversing the space in increasing order of object addresses. 1808 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1809 // Add the last bin which spans after the last object to the end of the space. 1810 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1811 } 1812 1813 private: 1814 struct BinContext { 1815 uintptr_t prev_; // The end of the previous object. 1816 ZygoteCompactingCollector* collector_; 1817 }; 1818 // Maps from bin sizes to locations. 1819 std::multimap<size_t, uintptr_t> bins_; 1820 // Live bitmap of the space which contains the bins. 1821 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1822 // Mark bitmap of the space which contains the bins. 1823 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1824 1825 static void Callback(mirror::Object* obj, void* arg) 1826 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1827 DCHECK(arg != nullptr); 1828 BinContext* context = reinterpret_cast<BinContext*>(arg); 1829 ZygoteCompactingCollector* collector = context->collector_; 1830 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1831 size_t bin_size = object_addr - context->prev_; 1832 // Add the bin consisting of the end of the previous object to the start of the current object. 1833 collector->AddBin(bin_size, context->prev_); 1834 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1835 } 1836 1837 void AddBin(size_t size, uintptr_t position) { 1838 if (size != 0) { 1839 bins_.insert(std::make_pair(size, position)); 1840 } 1841 } 1842 1843 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1844 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1845 // allocator. 1846 return false; 1847 } 1848 1849 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1850 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1851 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1852 mirror::Object* forward_address; 1853 // Find the smallest bin which we can move obj in. 1854 auto it = bins_.lower_bound(object_size); 1855 if (it == bins_.end()) { 1856 // No available space in the bins, place it in the target space instead (grows the zygote 1857 // space). 1858 size_t bytes_allocated; 1859 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1860 if (to_space_live_bitmap_ != nullptr) { 1861 to_space_live_bitmap_->Set(forward_address); 1862 } else { 1863 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1864 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1865 } 1866 } else { 1867 size_t size = it->first; 1868 uintptr_t pos = it->second; 1869 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1870 forward_address = reinterpret_cast<mirror::Object*>(pos); 1871 // Set the live and mark bits so that sweeping system weaks works properly. 1872 bin_live_bitmap_->Set(forward_address); 1873 bin_mark_bitmap_->Set(forward_address); 1874 DCHECK_GE(size, object_size); 1875 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1876 } 1877 // Copy the object over to its new location. 1878 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1879 if (kUseBakerOrBrooksReadBarrier) { 1880 obj->AssertReadBarrierPointer(); 1881 if (kUseBrooksReadBarrier) { 1882 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1883 forward_address->SetReadBarrierPointer(forward_address); 1884 } 1885 forward_address->AssertReadBarrierPointer(); 1886 } 1887 return forward_address; 1888 } 1889 }; 1890 1891 void Heap::UnBindBitmaps() { 1892 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1893 for (const auto& space : GetContinuousSpaces()) { 1894 if (space->IsContinuousMemMapAllocSpace()) { 1895 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1896 if (alloc_space->HasBoundBitmaps()) { 1897 alloc_space->UnBindBitmaps(); 1898 } 1899 } 1900 } 1901 } 1902 1903 void Heap::PreZygoteFork() { 1904 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1905 Thread* self = Thread::Current(); 1906 MutexLock mu(self, zygote_creation_lock_); 1907 // Try to see if we have any Zygote spaces. 1908 if (have_zygote_space_) { 1909 return; 1910 } 1911 VLOG(heap) << "Starting PreZygoteFork"; 1912 // Trim the pages at the end of the non moving space. 1913 non_moving_space_->Trim(); 1914 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1915 // there. 1916 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1917 const bool same_space = non_moving_space_ == main_space_; 1918 if (kCompactZygote) { 1919 // Can't compact if the non moving space is the same as the main space. 1920 DCHECK(semi_space_collector_ != nullptr); 1921 // Temporarily disable rosalloc verification because the zygote 1922 // compaction will mess up the rosalloc internal metadata. 1923 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1924 ZygoteCompactingCollector zygote_collector(this); 1925 zygote_collector.BuildBins(non_moving_space_); 1926 // Create a new bump pointer space which we will compact into. 1927 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1928 non_moving_space_->Limit()); 1929 // Compact the bump pointer space to a new zygote bump pointer space. 1930 bool reset_main_space = false; 1931 if (IsMovingGc(collector_type_)) { 1932 zygote_collector.SetFromSpace(bump_pointer_space_); 1933 } else { 1934 CHECK(main_space_ != nullptr); 1935 // Copy from the main space. 1936 zygote_collector.SetFromSpace(main_space_); 1937 reset_main_space = true; 1938 } 1939 zygote_collector.SetToSpace(&target_space); 1940 zygote_collector.SetSwapSemiSpaces(false); 1941 zygote_collector.Run(kGcCauseCollectorTransition, false); 1942 if (reset_main_space) { 1943 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1944 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1945 MemMap* mem_map = main_space_->ReleaseMemMap(); 1946 RemoveSpace(main_space_); 1947 space::Space* old_main_space = main_space_; 1948 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1949 delete old_main_space; 1950 AddSpace(main_space_); 1951 } else { 1952 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1953 } 1954 if (temp_space_ != nullptr) { 1955 CHECK(temp_space_->IsEmpty()); 1956 } 1957 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1958 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1959 // Update the end and write out image. 1960 non_moving_space_->SetEnd(target_space.End()); 1961 non_moving_space_->SetLimit(target_space.Limit()); 1962 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1963 } 1964 // Change the collector to the post zygote one. 1965 ChangeCollector(foreground_collector_type_); 1966 // Save the old space so that we can remove it after we complete creating the zygote space. 1967 space::MallocSpace* old_alloc_space = non_moving_space_; 1968 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1969 // the remaining available space. 1970 // Remove the old space before creating the zygote space since creating the zygote space sets 1971 // the old alloc space's bitmaps to nullptr. 1972 RemoveSpace(old_alloc_space); 1973 if (collector::SemiSpace::kUseRememberedSet) { 1974 // Sanity bound check. 1975 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1976 // Remove the remembered set for the now zygote space (the old 1977 // non-moving space). Note now that we have compacted objects into 1978 // the zygote space, the data in the remembered set is no longer 1979 // needed. The zygote space will instead have a mod-union table 1980 // from this point on. 1981 RemoveRememberedSet(old_alloc_space); 1982 } 1983 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1984 low_memory_mode_, 1985 &non_moving_space_); 1986 CHECK(!non_moving_space_->CanMoveObjects()); 1987 if (same_space) { 1988 main_space_ = non_moving_space_; 1989 SetSpaceAsDefault(main_space_); 1990 } 1991 delete old_alloc_space; 1992 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1993 AddSpace(zygote_space); 1994 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1995 AddSpace(non_moving_space_); 1996 have_zygote_space_ = true; 1997 // Enable large object space allocations. 1998 large_object_threshold_ = kDefaultLargeObjectThreshold; 1999 // Create the zygote space mod union table. 2000 accounting::ModUnionTable* mod_union_table = 2001 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 2002 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 2003 AddModUnionTable(mod_union_table); 2004 if (collector::SemiSpace::kUseRememberedSet) { 2005 // Add a new remembered set for the post-zygote non-moving space. 2006 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 2007 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 2008 non_moving_space_); 2009 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 2010 << "Failed to create post-zygote non-moving space remembered set"; 2011 AddRememberedSet(post_zygote_non_moving_space_rem_set); 2012 } 2013 } 2014 2015 void Heap::FlushAllocStack() { 2016 MarkAllocStackAsLive(allocation_stack_.get()); 2017 allocation_stack_->Reset(); 2018 } 2019 2020 void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2021 accounting::ContinuousSpaceBitmap* bitmap2, 2022 accounting::LargeObjectBitmap* large_objects, 2023 accounting::ObjectStack* stack) { 2024 DCHECK(bitmap1 != nullptr); 2025 DCHECK(bitmap2 != nullptr); 2026 mirror::Object** limit = stack->End(); 2027 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2028 const mirror::Object* obj = *it; 2029 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2030 if (bitmap1->HasAddress(obj)) { 2031 bitmap1->Set(obj); 2032 } else if (bitmap2->HasAddress(obj)) { 2033 bitmap2->Set(obj); 2034 } else { 2035 large_objects->Set(obj); 2036 } 2037 } 2038 } 2039 } 2040 2041 void Heap::SwapSemiSpaces() { 2042 CHECK(bump_pointer_space_ != nullptr); 2043 CHECK(temp_space_ != nullptr); 2044 std::swap(bump_pointer_space_, temp_space_); 2045 } 2046 2047 void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2048 space::ContinuousMemMapAllocSpace* source_space, 2049 GcCause gc_cause) { 2050 CHECK(kMovingCollector); 2051 if (target_space != source_space) { 2052 // Don't swap spaces since this isn't a typical semi space collection. 2053 semi_space_collector_->SetSwapSemiSpaces(false); 2054 semi_space_collector_->SetFromSpace(source_space); 2055 semi_space_collector_->SetToSpace(target_space); 2056 semi_space_collector_->Run(gc_cause, false); 2057 } else { 2058 CHECK(target_space->IsBumpPointerSpace()) 2059 << "In-place compaction is only supported for bump pointer spaces"; 2060 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2061 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2062 } 2063 } 2064 2065 collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2066 bool clear_soft_references) { 2067 Thread* self = Thread::Current(); 2068 Runtime* runtime = Runtime::Current(); 2069 // If the heap can't run the GC, silently fail and return that no GC was run. 2070 switch (gc_type) { 2071 case collector::kGcTypePartial: { 2072 if (!have_zygote_space_) { 2073 return collector::kGcTypeNone; 2074 } 2075 break; 2076 } 2077 default: { 2078 // Other GC types don't have any special cases which makes them not runnable. The main case 2079 // here is full GC. 2080 } 2081 } 2082 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2083 Locks::mutator_lock_->AssertNotHeld(self); 2084 if (self->IsHandlingStackOverflow()) { 2085 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2086 } 2087 bool compacting_gc; 2088 { 2089 gc_complete_lock_->AssertNotHeld(self); 2090 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2091 MutexLock mu(self, *gc_complete_lock_); 2092 // Ensure there is only one GC at a time. 2093 WaitForGcToCompleteLocked(gc_cause, self); 2094 compacting_gc = IsMovingGc(collector_type_); 2095 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2096 if (compacting_gc && disable_moving_gc_count_ != 0) { 2097 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2098 return collector::kGcTypeNone; 2099 } 2100 collector_type_running_ = collector_type_; 2101 } 2102 2103 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2104 ++runtime->GetStats()->gc_for_alloc_count; 2105 ++self->GetStats()->gc_for_alloc_count; 2106 } 2107 uint64_t gc_start_time_ns = NanoTime(); 2108 uint64_t gc_start_size = GetBytesAllocated(); 2109 // Approximate allocation rate in bytes / second. 2110 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2111 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2112 if (LIKELY(ms_delta != 0)) { 2113 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2114 ATRACE_INT("Allocation rate KB/s", allocation_rate_ / KB); 2115 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2116 } 2117 2118 DCHECK_LT(gc_type, collector::kGcTypeMax); 2119 DCHECK_NE(gc_type, collector::kGcTypeNone); 2120 2121 collector::GarbageCollector* collector = nullptr; 2122 // TODO: Clean this up. 2123 if (compacting_gc) { 2124 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2125 current_allocator_ == kAllocatorTypeTLAB); 2126 switch (collector_type_) { 2127 case kCollectorTypeSS: 2128 // Fall-through. 2129 case kCollectorTypeGSS: 2130 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2131 semi_space_collector_->SetToSpace(temp_space_); 2132 semi_space_collector_->SetSwapSemiSpaces(true); 2133 collector = semi_space_collector_; 2134 break; 2135 case kCollectorTypeCC: 2136 collector = concurrent_copying_collector_; 2137 break; 2138 case kCollectorTypeMC: 2139 mark_compact_collector_->SetSpace(bump_pointer_space_); 2140 collector = mark_compact_collector_; 2141 break; 2142 default: 2143 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2144 } 2145 if (collector != mark_compact_collector_) { 2146 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2147 CHECK(temp_space_->IsEmpty()); 2148 } 2149 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2150 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2151 current_allocator_ == kAllocatorTypeDlMalloc) { 2152 collector = FindCollectorByGcType(gc_type); 2153 } else { 2154 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2155 } 2156 CHECK(collector != nullptr) 2157 << "Could not find garbage collector with collector_type=" 2158 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2159 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2160 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2161 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2162 RequestHeapTrim(); 2163 // Enqueue cleared references. 2164 reference_processor_.EnqueueClearedReferences(self); 2165 // Grow the heap so that we know when to perform the next GC. 2166 GrowForUtilization(collector); 2167 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2168 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2169 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2170 // (mutator time blocked >= long_pause_log_threshold_). 2171 bool log_gc = gc_cause == kGcCauseExplicit; 2172 if (!log_gc && CareAboutPauseTimes()) { 2173 // GC for alloc pauses the allocating thread, so consider it as a pause. 2174 log_gc = duration > long_gc_log_threshold_ || 2175 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2176 for (uint64_t pause : pause_times) { 2177 log_gc = log_gc || pause >= long_pause_log_threshold_; 2178 } 2179 } 2180 if (log_gc) { 2181 const size_t percent_free = GetPercentFree(); 2182 const size_t current_heap_size = GetBytesAllocated(); 2183 const size_t total_memory = GetTotalMemory(); 2184 std::ostringstream pause_string; 2185 for (size_t i = 0; i < pause_times.size(); ++i) { 2186 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2187 << ((i != pause_times.size() - 1) ? "," : ""); 2188 } 2189 LOG(INFO) << gc_cause << " " << collector->GetName() 2190 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2191 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2192 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2193 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2194 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2195 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2196 << " total " << PrettyDuration((duration / 1000) * 1000); 2197 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2198 } 2199 FinishGC(self, gc_type); 2200 // Inform DDMS that a GC completed. 2201 Dbg::GcDidFinish(); 2202 return gc_type; 2203 } 2204 2205 void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2206 MutexLock mu(self, *gc_complete_lock_); 2207 collector_type_running_ = kCollectorTypeNone; 2208 if (gc_type != collector::kGcTypeNone) { 2209 last_gc_type_ = gc_type; 2210 } 2211 // Wake anyone who may have been waiting for the GC to complete. 2212 gc_complete_cond_->Broadcast(self); 2213 } 2214 2215 static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2216 RootType /*root_type*/) { 2217 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2218 if (*root == obj) { 2219 LOG(INFO) << "Object " << obj << " is a root"; 2220 } 2221 } 2222 2223 class ScanVisitor { 2224 public: 2225 void operator()(const mirror::Object* obj) const { 2226 LOG(ERROR) << "Would have rescanned object " << obj; 2227 } 2228 }; 2229 2230 // Verify a reference from an object. 2231 class VerifyReferenceVisitor { 2232 public: 2233 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2234 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2235 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2236 2237 size_t GetFailureCount() const { 2238 return fail_count_->LoadSequentiallyConsistent(); 2239 } 2240 2241 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2242 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2243 if (verify_referent_) { 2244 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2245 } 2246 } 2247 2248 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2249 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2250 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2251 } 2252 2253 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2254 return heap_->IsLiveObjectLocked(obj, true, false, true); 2255 } 2256 2257 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2258 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2259 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2260 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2261 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2262 << " thread_id= " << thread_id << " root_type= " << root_type; 2263 } 2264 } 2265 2266 private: 2267 // TODO: Fix the no thread safety analysis. 2268 // Returns false on failure. 2269 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2270 NO_THREAD_SAFETY_ANALYSIS { 2271 if (ref == nullptr || IsLive(ref)) { 2272 // Verify that the reference is live. 2273 return true; 2274 } 2275 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2276 // Print message on only on first failure to prevent spam. 2277 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2278 } 2279 if (obj != nullptr) { 2280 // Only do this part for non roots. 2281 accounting::CardTable* card_table = heap_->GetCardTable(); 2282 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2283 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2284 byte* card_addr = card_table->CardFromAddr(obj); 2285 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2286 << offset << "\n card value = " << static_cast<int>(*card_addr); 2287 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2288 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2289 } else { 2290 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2291 } 2292 2293 // Attempt to find the class inside of the recently freed objects. 2294 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2295 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2296 space::MallocSpace* space = ref_space->AsMallocSpace(); 2297 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2298 if (ref_class != nullptr) { 2299 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2300 << PrettyClass(ref_class); 2301 } else { 2302 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2303 } 2304 } 2305 2306 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2307 ref->GetClass()->IsClass()) { 2308 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2309 } else { 2310 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2311 << ") is not a valid heap address"; 2312 } 2313 2314 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2315 void* cover_begin = card_table->AddrFromCard(card_addr); 2316 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2317 accounting::CardTable::kCardSize); 2318 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2319 << "-" << cover_end; 2320 accounting::ContinuousSpaceBitmap* bitmap = 2321 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2322 2323 if (bitmap == nullptr) { 2324 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2325 if (!VerifyClassClass(obj->GetClass())) { 2326 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2327 } 2328 } else { 2329 // Print out how the object is live. 2330 if (bitmap->Test(obj)) { 2331 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2332 } 2333 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2334 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2335 } 2336 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2337 LOG(ERROR) << "Object " << obj << " found in live stack"; 2338 } 2339 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2340 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2341 } 2342 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2343 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2344 } 2345 // Attempt to see if the card table missed the reference. 2346 ScanVisitor scan_visitor; 2347 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2348 card_table->Scan(bitmap, byte_cover_begin, 2349 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2350 } 2351 2352 // Search to see if any of the roots reference our object. 2353 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2354 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2355 2356 // Search to see if any of the roots reference our reference. 2357 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2358 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2359 } 2360 return false; 2361 } 2362 2363 Heap* const heap_; 2364 Atomic<size_t>* const fail_count_; 2365 const bool verify_referent_; 2366 }; 2367 2368 // Verify all references within an object, for use with HeapBitmap::Visit. 2369 class VerifyObjectVisitor { 2370 public: 2371 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2372 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2373 } 2374 2375 void operator()(mirror::Object* obj) const 2376 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2377 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2378 // be live or else how did we find it in the live bitmap? 2379 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2380 // The class doesn't count as a reference but we should verify it anyways. 2381 obj->VisitReferences<true>(visitor, visitor); 2382 } 2383 2384 static void VisitCallback(mirror::Object* obj, void* arg) 2385 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2386 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2387 visitor->operator()(obj); 2388 } 2389 2390 size_t GetFailureCount() const { 2391 return fail_count_->LoadSequentiallyConsistent(); 2392 } 2393 2394 private: 2395 Heap* const heap_; 2396 Atomic<size_t>* const fail_count_; 2397 const bool verify_referent_; 2398 }; 2399 2400 void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2401 // Slow path, the allocation stack push back must have already failed. 2402 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2403 do { 2404 // TODO: Add handle VerifyObject. 2405 StackHandleScope<1> hs(self); 2406 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2407 // Push our object into the reserve region of the allocaiton stack. This is only required due 2408 // to heap verification requiring that roots are live (either in the live bitmap or in the 2409 // allocation stack). 2410 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2411 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2412 } while (!allocation_stack_->AtomicPushBack(*obj)); 2413 } 2414 2415 void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2416 // Slow path, the allocation stack push back must have already failed. 2417 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2418 mirror::Object** start_address; 2419 mirror::Object** end_address; 2420 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2421 &end_address)) { 2422 // TODO: Add handle VerifyObject. 2423 StackHandleScope<1> hs(self); 2424 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2425 // Push our object into the reserve region of the allocaiton stack. This is only required due 2426 // to heap verification requiring that roots are live (either in the live bitmap or in the 2427 // allocation stack). 2428 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2429 // Push into the reserve allocation stack. 2430 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2431 } 2432 self->SetThreadLocalAllocationStack(start_address, end_address); 2433 // Retry on the new thread-local allocation stack. 2434 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2435 } 2436 2437 // Must do this with mutators suspended since we are directly accessing the allocation stacks. 2438 size_t Heap::VerifyHeapReferences(bool verify_referents) { 2439 Thread* self = Thread::Current(); 2440 Locks::mutator_lock_->AssertExclusiveHeld(self); 2441 // Lets sort our allocation stacks so that we can efficiently binary search them. 2442 allocation_stack_->Sort(); 2443 live_stack_->Sort(); 2444 // Since we sorted the allocation stack content, need to revoke all 2445 // thread-local allocation stacks. 2446 RevokeAllThreadLocalAllocationStacks(self); 2447 Atomic<size_t> fail_count_(0); 2448 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2449 // Verify objects in the allocation stack since these will be objects which were: 2450 // 1. Allocated prior to the GC (pre GC verification). 2451 // 2. Allocated during the GC (pre sweep GC verification). 2452 // We don't want to verify the objects in the live stack since they themselves may be 2453 // pointing to dead objects if they are not reachable. 2454 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2455 // Verify the roots: 2456 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2457 if (visitor.GetFailureCount() > 0) { 2458 // Dump mod-union tables. 2459 for (const auto& table_pair : mod_union_tables_) { 2460 accounting::ModUnionTable* mod_union_table = table_pair.second; 2461 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2462 } 2463 // Dump remembered sets. 2464 for (const auto& table_pair : remembered_sets_) { 2465 accounting::RememberedSet* remembered_set = table_pair.second; 2466 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2467 } 2468 DumpSpaces(LOG(ERROR)); 2469 } 2470 return visitor.GetFailureCount(); 2471 } 2472 2473 class VerifyReferenceCardVisitor { 2474 public: 2475 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2476 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2477 Locks::heap_bitmap_lock_) 2478 : heap_(heap), failed_(failed) { 2479 } 2480 2481 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2482 // annotalysis on visitors. 2483 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2484 NO_THREAD_SAFETY_ANALYSIS { 2485 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2486 // Filter out class references since changing an object's class does not mark the card as dirty. 2487 // Also handles large objects, since the only reference they hold is a class reference. 2488 if (ref != nullptr && !ref->IsClass()) { 2489 accounting::CardTable* card_table = heap_->GetCardTable(); 2490 // If the object is not dirty and it is referencing something in the live stack other than 2491 // class, then it must be on a dirty card. 2492 if (!card_table->AddrIsInCardTable(obj)) { 2493 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2494 *failed_ = true; 2495 } else if (!card_table->IsDirty(obj)) { 2496 // TODO: Check mod-union tables. 2497 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2498 // kCardDirty - 1 if it didnt get touched since we aged it. 2499 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2500 if (live_stack->ContainsSorted(ref)) { 2501 if (live_stack->ContainsSorted(obj)) { 2502 LOG(ERROR) << "Object " << obj << " found in live stack"; 2503 } 2504 if (heap_->GetLiveBitmap()->Test(obj)) { 2505 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2506 } 2507 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2508 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2509 2510 // Print which field of the object is dead. 2511 if (!obj->IsObjectArray()) { 2512 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2513 CHECK(klass != NULL); 2514 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2515 : klass->GetIFields(); 2516 CHECK(fields != NULL); 2517 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2518 mirror::ArtField* cur = fields->Get(i); 2519 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2520 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2521 << PrettyField(cur); 2522 break; 2523 } 2524 } 2525 } else { 2526 mirror::ObjectArray<mirror::Object>* object_array = 2527 obj->AsObjectArray<mirror::Object>(); 2528 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2529 if (object_array->Get(i) == ref) { 2530 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2531 } 2532 } 2533 } 2534 2535 *failed_ = true; 2536 } 2537 } 2538 } 2539 } 2540 2541 private: 2542 Heap* const heap_; 2543 bool* const failed_; 2544 }; 2545 2546 class VerifyLiveStackReferences { 2547 public: 2548 explicit VerifyLiveStackReferences(Heap* heap) 2549 : heap_(heap), 2550 failed_(false) {} 2551 2552 void operator()(mirror::Object* obj) const 2553 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2554 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2555 obj->VisitReferences<true>(visitor, VoidFunctor()); 2556 } 2557 2558 bool Failed() const { 2559 return failed_; 2560 } 2561 2562 private: 2563 Heap* const heap_; 2564 bool failed_; 2565 }; 2566 2567 bool Heap::VerifyMissingCardMarks() { 2568 Thread* self = Thread::Current(); 2569 Locks::mutator_lock_->AssertExclusiveHeld(self); 2570 // We need to sort the live stack since we binary search it. 2571 live_stack_->Sort(); 2572 // Since we sorted the allocation stack content, need to revoke all 2573 // thread-local allocation stacks. 2574 RevokeAllThreadLocalAllocationStacks(self); 2575 VerifyLiveStackReferences visitor(this); 2576 GetLiveBitmap()->Visit(visitor); 2577 // We can verify objects in the live stack since none of these should reference dead objects. 2578 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2579 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2580 visitor(*it); 2581 } 2582 } 2583 return !visitor.Failed(); 2584 } 2585 2586 void Heap::SwapStacks(Thread* self) { 2587 if (kUseThreadLocalAllocationStack) { 2588 live_stack_->AssertAllZero(); 2589 } 2590 allocation_stack_.swap(live_stack_); 2591 } 2592 2593 void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2594 // This must be called only during the pause. 2595 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2596 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2597 MutexLock mu2(self, *Locks::thread_list_lock_); 2598 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2599 for (Thread* t : thread_list) { 2600 t->RevokeThreadLocalAllocationStack(); 2601 } 2602 } 2603 2604 void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2605 if (kIsDebugBuild) { 2606 if (bump_pointer_space_ != nullptr) { 2607 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2608 } 2609 } 2610 } 2611 2612 accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2613 auto it = mod_union_tables_.find(space); 2614 if (it == mod_union_tables_.end()) { 2615 return nullptr; 2616 } 2617 return it->second; 2618 } 2619 2620 accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2621 auto it = remembered_sets_.find(space); 2622 if (it == remembered_sets_.end()) { 2623 return nullptr; 2624 } 2625 return it->second; 2626 } 2627 2628 void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2629 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2630 // Clear cards and keep track of cards cleared in the mod-union table. 2631 for (const auto& space : continuous_spaces_) { 2632 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2633 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2634 if (table != nullptr) { 2635 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2636 "ImageModUnionClearCards"; 2637 TimingLogger::ScopedTiming t(name, timings); 2638 table->ClearCards(); 2639 } else if (use_rem_sets && rem_set != nullptr) { 2640 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2641 << static_cast<int>(collector_type_); 2642 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2643 rem_set->ClearCards(); 2644 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2645 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2646 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2647 // were dirty before the GC started. 2648 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2649 // -> clean(cleaning thread). 2650 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2651 // roots and then we scan / update mod union tables after. We will always scan either card. 2652 // If we end up with the non aged card, we scan it it in the pause. 2653 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2654 VoidFunctor()); 2655 } 2656 } 2657 } 2658 2659 static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2660 } 2661 2662 void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2663 Thread* const self = Thread::Current(); 2664 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2665 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2666 if (verify_pre_gc_heap_) { 2667 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2668 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2669 size_t failures = VerifyHeapReferences(); 2670 if (failures > 0) { 2671 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2672 << " failures"; 2673 } 2674 } 2675 // Check that all objects which reference things in the live stack are on dirty cards. 2676 if (verify_missing_card_marks_) { 2677 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2678 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2679 SwapStacks(self); 2680 // Sort the live stack so that we can quickly binary search it later. 2681 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2682 << " missing card mark verification failed\n" << DumpSpaces(); 2683 SwapStacks(self); 2684 } 2685 if (verify_mod_union_table_) { 2686 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2687 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2688 for (const auto& table_pair : mod_union_tables_) { 2689 accounting::ModUnionTable* mod_union_table = table_pair.second; 2690 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2691 mod_union_table->Verify(); 2692 } 2693 } 2694 } 2695 2696 void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2697 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2698 collector::GarbageCollector::ScopedPause pause(gc); 2699 PreGcVerificationPaused(gc); 2700 } 2701 } 2702 2703 void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2704 // TODO: Add a new runtime option for this? 2705 if (verify_pre_gc_rosalloc_) { 2706 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2707 } 2708 } 2709 2710 void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2711 Thread* const self = Thread::Current(); 2712 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2713 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2714 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2715 // reachable objects. 2716 if (verify_pre_sweeping_heap_) { 2717 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2718 CHECK_NE(self->GetState(), kRunnable); 2719 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2720 // Swapping bound bitmaps does nothing. 2721 gc->SwapBitmaps(); 2722 // Pass in false since concurrent reference processing can mean that the reference referents 2723 // may point to dead objects at the point which PreSweepingGcVerification is called. 2724 size_t failures = VerifyHeapReferences(false); 2725 if (failures > 0) { 2726 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2727 << " failures"; 2728 } 2729 gc->SwapBitmaps(); 2730 } 2731 if (verify_pre_sweeping_rosalloc_) { 2732 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2733 } 2734 } 2735 2736 void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2737 // Only pause if we have to do some verification. 2738 Thread* const self = Thread::Current(); 2739 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2740 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2741 if (verify_system_weaks_) { 2742 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2743 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2744 mark_sweep->VerifySystemWeaks(); 2745 } 2746 if (verify_post_gc_rosalloc_) { 2747 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2748 } 2749 if (verify_post_gc_heap_) { 2750 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2751 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2752 size_t failures = VerifyHeapReferences(); 2753 if (failures > 0) { 2754 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2755 << " failures"; 2756 } 2757 } 2758 } 2759 2760 void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2761 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2762 collector::GarbageCollector::ScopedPause pause(gc); 2763 PostGcVerificationPaused(gc); 2764 } 2765 } 2766 2767 void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2768 TimingLogger::ScopedTiming t(name, timings); 2769 for (const auto& space : continuous_spaces_) { 2770 if (space->IsRosAllocSpace()) { 2771 VLOG(heap) << name << " : " << space->GetName(); 2772 space->AsRosAllocSpace()->Verify(); 2773 } 2774 } 2775 } 2776 2777 collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2778 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2779 MutexLock mu(self, *gc_complete_lock_); 2780 return WaitForGcToCompleteLocked(cause, self); 2781 } 2782 2783 collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2784 collector::GcType last_gc_type = collector::kGcTypeNone; 2785 uint64_t wait_start = NanoTime(); 2786 while (collector_type_running_ != kCollectorTypeNone) { 2787 ATRACE_BEGIN("GC: Wait For Completion"); 2788 // We must wait, change thread state then sleep on gc_complete_cond_; 2789 gc_complete_cond_->Wait(self); 2790 last_gc_type = last_gc_type_; 2791 ATRACE_END(); 2792 } 2793 uint64_t wait_time = NanoTime() - wait_start; 2794 total_wait_time_ += wait_time; 2795 if (wait_time > long_pause_log_threshold_) { 2796 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2797 << " for cause " << cause; 2798 } 2799 return last_gc_type; 2800 } 2801 2802 void Heap::DumpForSigQuit(std::ostream& os) { 2803 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2804 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2805 DumpGcPerformanceInfo(os); 2806 } 2807 2808 size_t Heap::GetPercentFree() { 2809 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2810 } 2811 2812 void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2813 if (max_allowed_footprint > GetMaxMemory()) { 2814 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2815 << PrettySize(GetMaxMemory()); 2816 max_allowed_footprint = GetMaxMemory(); 2817 } 2818 max_allowed_footprint_ = max_allowed_footprint; 2819 } 2820 2821 bool Heap::IsMovableObject(const mirror::Object* obj) const { 2822 if (kMovingCollector) { 2823 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2824 if (space != nullptr) { 2825 // TODO: Check large object? 2826 return space->CanMoveObjects(); 2827 } 2828 } 2829 return false; 2830 } 2831 2832 void Heap::UpdateMaxNativeFootprint() { 2833 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2834 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2835 size_t target_size = native_size / GetTargetHeapUtilization(); 2836 if (target_size > native_size + max_free_) { 2837 target_size = native_size + max_free_; 2838 } else if (target_size < native_size + min_free_) { 2839 target_size = native_size + min_free_; 2840 } 2841 native_footprint_gc_watermark_ = std::min(growth_limit_, target_size); 2842 } 2843 2844 collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2845 for (const auto& collector : garbage_collectors_) { 2846 if (collector->GetCollectorType() == collector_type_ && 2847 collector->GetGcType() == gc_type) { 2848 return collector; 2849 } 2850 } 2851 return nullptr; 2852 } 2853 2854 double Heap::HeapGrowthMultiplier() const { 2855 // If we don't care about pause times we are background, so return 1.0. 2856 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2857 return 1.0; 2858 } 2859 return foreground_heap_growth_multiplier_; 2860 } 2861 2862 void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2863 // We know what our utilization is at this moment. 2864 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2865 const uint64_t bytes_allocated = GetBytesAllocated(); 2866 last_gc_size_ = bytes_allocated; 2867 last_gc_time_ns_ = NanoTime(); 2868 uint64_t target_size; 2869 collector::GcType gc_type = collector_ran->GetGcType(); 2870 if (gc_type != collector::kGcTypeSticky) { 2871 // Grow the heap for non sticky GC. 2872 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2873 // foreground. 2874 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2875 CHECK_GE(delta, 0); 2876 target_size = bytes_allocated + delta * multiplier; 2877 target_size = std::min(target_size, 2878 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2879 target_size = std::max(target_size, 2880 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2881 native_need_to_run_finalization_ = true; 2882 next_gc_type_ = collector::kGcTypeSticky; 2883 } else { 2884 collector::GcType non_sticky_gc_type = 2885 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2886 // Find what the next non sticky collector will be. 2887 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2888 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2889 // do another sticky collection next. 2890 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2891 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2892 // if the sticky GC throughput always remained >= the full/partial throughput. 2893 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2894 non_sticky_collector->GetEstimatedMeanThroughput() && 2895 non_sticky_collector->NumberOfIterations() > 0 && 2896 bytes_allocated <= max_allowed_footprint_) { 2897 next_gc_type_ = collector::kGcTypeSticky; 2898 } else { 2899 next_gc_type_ = non_sticky_gc_type; 2900 } 2901 // If we have freed enough memory, shrink the heap back down. 2902 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2903 target_size = bytes_allocated + max_free_; 2904 } else { 2905 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2906 } 2907 } 2908 if (!ignore_max_footprint_) { 2909 SetIdealFootprint(target_size); 2910 if (IsGcConcurrent()) { 2911 // Calculate when to perform the next ConcurrentGC. 2912 // Calculate the estimated GC duration. 2913 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2914 // Estimate how many remaining bytes we will have when we need to start the next GC. 2915 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2916 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2917 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2918 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2919 // A never going to happen situation that from the estimated allocation rate we will exceed 2920 // the applications entire footprint with the given estimated allocation rate. Schedule 2921 // another GC nearly straight away. 2922 remaining_bytes = kMinConcurrentRemainingBytes; 2923 } 2924 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2925 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2926 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2927 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2928 // right away. 2929 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2930 static_cast<size_t>(bytes_allocated)); 2931 } 2932 } 2933 } 2934 2935 void Heap::ClearGrowthLimit() { 2936 growth_limit_ = capacity_; 2937 non_moving_space_->ClearGrowthLimit(); 2938 } 2939 2940 void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2941 ScopedObjectAccess soa(self); 2942 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2943 jvalue args[1]; 2944 args[0].l = arg.get(); 2945 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2946 // Restore object in case it gets moved. 2947 *object = soa.Decode<mirror::Object*>(arg.get()); 2948 } 2949 2950 void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2951 StackHandleScope<1> hs(self); 2952 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2953 RequestConcurrentGC(self); 2954 } 2955 2956 void Heap::RequestConcurrentGC(Thread* self) { 2957 // Make sure that we can do a concurrent GC. 2958 Runtime* runtime = Runtime::Current(); 2959 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2960 self->IsHandlingStackOverflow()) { 2961 return; 2962 } 2963 // We already have a request pending, no reason to start more until we update 2964 // concurrent_start_bytes_. 2965 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2966 JNIEnv* env = self->GetJniEnv(); 2967 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2968 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2969 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2970 WellKnownClasses::java_lang_Daemons_requestGC); 2971 CHECK(!env->ExceptionCheck()); 2972 } 2973 2974 void Heap::ConcurrentGC(Thread* self) { 2975 if (Runtime::Current()->IsShuttingDown(self)) { 2976 return; 2977 } 2978 // Wait for any GCs currently running to finish. 2979 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2980 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2981 // instead. E.g. can't do partial, so do full instead. 2982 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2983 collector::kGcTypeNone) { 2984 for (collector::GcType gc_type : gc_plan_) { 2985 // Attempt to run the collector, if we succeed, we are done. 2986 if (gc_type > next_gc_type_ && 2987 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2988 break; 2989 } 2990 } 2991 } 2992 } 2993 } 2994 2995 void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2996 Thread* self = Thread::Current(); 2997 { 2998 MutexLock mu(self, *heap_trim_request_lock_); 2999 if (desired_collector_type_ == desired_collector_type) { 3000 return; 3001 } 3002 heap_transition_or_trim_target_time_ = 3003 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 3004 desired_collector_type_ = desired_collector_type; 3005 } 3006 SignalHeapTrimDaemon(self); 3007 } 3008 3009 void Heap::RequestHeapTrim() { 3010 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 3011 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 3012 // a space it will hold its lock and can become a cause of jank. 3013 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 3014 // forking. 3015 3016 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 3017 // because that only marks object heads, so a large array looks like lots of empty space. We 3018 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 3019 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3020 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3021 // not how much use we're making of those pages. 3022 3023 Thread* self = Thread::Current(); 3024 Runtime* runtime = Runtime::Current(); 3025 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 3026 runtime->IsZygote()) { 3027 // Ignore the request if we are the zygote to prevent app launching lag due to sleep in heap 3028 // trimmer daemon. b/17310019 3029 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3030 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3031 // as we don't hold the lock while requesting the trim). 3032 return; 3033 } 3034 { 3035 MutexLock mu(self, *heap_trim_request_lock_); 3036 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3037 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3038 // just yet. 3039 return; 3040 } 3041 heap_trim_request_pending_ = true; 3042 uint64_t current_time = NanoTime(); 3043 if (heap_transition_or_trim_target_time_ < current_time) { 3044 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 3045 } 3046 } 3047 // Notify the daemon thread which will actually do the heap trim. 3048 SignalHeapTrimDaemon(self); 3049 } 3050 3051 void Heap::SignalHeapTrimDaemon(Thread* self) { 3052 JNIEnv* env = self->GetJniEnv(); 3053 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3054 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3055 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3056 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3057 CHECK(!env->ExceptionCheck()); 3058 } 3059 3060 void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3061 if (rosalloc_space_ != nullptr) { 3062 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3063 } 3064 if (bump_pointer_space_ != nullptr) { 3065 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3066 } 3067 } 3068 3069 void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3070 if (rosalloc_space_ != nullptr) { 3071 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3072 } 3073 } 3074 3075 void Heap::RevokeAllThreadLocalBuffers() { 3076 if (rosalloc_space_ != nullptr) { 3077 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3078 } 3079 if (bump_pointer_space_ != nullptr) { 3080 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3081 } 3082 } 3083 3084 bool Heap::IsGCRequestPending() const { 3085 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3086 } 3087 3088 void Heap::RunFinalization(JNIEnv* env) { 3089 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3090 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3091 CHECK(WellKnownClasses::java_lang_System != nullptr); 3092 WellKnownClasses::java_lang_System_runFinalization = 3093 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3094 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3095 } 3096 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3097 WellKnownClasses::java_lang_System_runFinalization); 3098 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3099 WellKnownClasses::java_lang_System_runFinalization); 3100 } 3101 3102 void Heap::RegisterNativeAllocation(JNIEnv* env, size_t bytes) { 3103 Thread* self = ThreadForEnv(env); 3104 if (native_need_to_run_finalization_) { 3105 RunFinalization(env); 3106 UpdateMaxNativeFootprint(); 3107 native_need_to_run_finalization_ = false; 3108 } 3109 // Total number of native bytes allocated. 3110 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3111 new_native_bytes_allocated += bytes; 3112 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3113 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 3114 collector::kGcTypeFull; 3115 3116 // The second watermark is higher than the gc watermark. If you hit this it means you are 3117 // allocating native objects faster than the GC can keep up with. 3118 if (new_native_bytes_allocated > growth_limit_) { 3119 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3120 // Just finished a GC, attempt to run finalizers. 3121 RunFinalization(env); 3122 CHECK(!env->ExceptionCheck()); 3123 } 3124 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3125 if (new_native_bytes_allocated > growth_limit_) { 3126 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3127 RunFinalization(env); 3128 native_need_to_run_finalization_ = false; 3129 CHECK(!env->ExceptionCheck()); 3130 } 3131 // We have just run finalizers, update the native watermark since it is very likely that 3132 // finalizers released native managed allocations. 3133 UpdateMaxNativeFootprint(); 3134 } else if (!IsGCRequestPending()) { 3135 if (IsGcConcurrent()) { 3136 RequestConcurrentGC(self); 3137 } else { 3138 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3139 } 3140 } 3141 } 3142 } 3143 3144 void Heap::RegisterNativeFree(JNIEnv* env, size_t bytes) { 3145 size_t expected_size; 3146 do { 3147 expected_size = native_bytes_allocated_.LoadRelaxed(); 3148 if (UNLIKELY(bytes > expected_size)) { 3149 ScopedObjectAccess soa(env); 3150 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3151 StringPrintf("Attempted to free %zd native bytes with only %zd native bytes " 3152 "registered as allocated", bytes, expected_size).c_str()); 3153 break; 3154 } 3155 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, 3156 expected_size - bytes)); 3157 } 3158 3159 size_t Heap::GetTotalMemory() const { 3160 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3161 } 3162 3163 void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3164 DCHECK(mod_union_table != nullptr); 3165 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3166 } 3167 3168 void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3169 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3170 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3171 CHECK_GE(byte_count, sizeof(mirror::Object)); 3172 } 3173 3174 void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3175 CHECK(remembered_set != nullptr); 3176 space::Space* space = remembered_set->GetSpace(); 3177 CHECK(space != nullptr); 3178 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3179 remembered_sets_.Put(space, remembered_set); 3180 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3181 } 3182 3183 void Heap::RemoveRememberedSet(space::Space* space) { 3184 CHECK(space != nullptr); 3185 auto it = remembered_sets_.find(space); 3186 CHECK(it != remembered_sets_.end()); 3187 delete it->second; 3188 remembered_sets_.erase(it); 3189 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3190 } 3191 3192 void Heap::ClearMarkedObjects() { 3193 // Clear all of the spaces' mark bitmaps. 3194 for (const auto& space : GetContinuousSpaces()) { 3195 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3196 if (space->GetLiveBitmap() != mark_bitmap) { 3197 mark_bitmap->Clear(); 3198 } 3199 } 3200 // Clear the marked objects in the discontinous space object sets. 3201 for (const auto& space : GetDiscontinuousSpaces()) { 3202 space->GetMarkBitmap()->Clear(); 3203 } 3204 } 3205 3206 } // namespace gc 3207 } // namespace art 3208
