heap.cc revision d81877cad7a6e9b97dfdc4c63984f218b7e31df5
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 71namespace art { 72 73namespace gc { 74 75static constexpr size_t kCollectorTransitionStressIterations = 0; 76static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 77static constexpr bool kGCALotMode = false; 78static constexpr size_t kGcAlotInterval = KB; 79// Minimum amount of remaining bytes before a concurrent GC is triggered. 80static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 81static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 82// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 83// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 84// threads (lower pauses, use less memory bandwidth). 85static constexpr double kStickyGcThroughputAdjustment = 1.0; 86// Whether or not we use the free list large object space. 87static constexpr bool kUseFreeListSpaceForLOS = false; 88// Whether or not we compact the zygote in PreZygoteFork. 89static constexpr bool kCompactZygote = kMovingCollector; 90// How many reserve entries are at the end of the allocation stack, these are only needed if the 91// allocation stack overflows. 92static constexpr size_t kAllocationStackReserveSize = 1024; 93// Default mark stack size in bytes. 94static const size_t kDefaultMarkStackSize = 64 * KB; 95// Define space name. 96static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 97static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 98static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 99static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 100 101Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 102 double target_utilization, double foreground_heap_growth_multiplier, 103 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 104 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 105 CollectorType background_collector_type, size_t parallel_gc_threads, 106 size_t conc_gc_threads, bool low_memory_mode, 107 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 108 bool ignore_max_footprint, bool use_tlab, 109 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 110 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 111 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 112 uint64_t min_interval_homogeneous_space_compaction_by_oom) 113 : non_moving_space_(nullptr), 114 rosalloc_space_(nullptr), 115 dlmalloc_space_(nullptr), 116 main_space_(nullptr), 117 collector_type_(kCollectorTypeNone), 118 foreground_collector_type_(foreground_collector_type), 119 background_collector_type_(background_collector_type), 120 desired_collector_type_(foreground_collector_type_), 121 heap_trim_request_lock_(nullptr), 122 last_trim_time_(0), 123 last_heap_transition_time_(0), 124 heap_trim_request_pending_(false), 125 parallel_gc_threads_(parallel_gc_threads), 126 conc_gc_threads_(conc_gc_threads), 127 low_memory_mode_(low_memory_mode), 128 long_pause_log_threshold_(long_pause_log_threshold), 129 long_gc_log_threshold_(long_gc_log_threshold), 130 ignore_max_footprint_(ignore_max_footprint), 131 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 132 have_zygote_space_(false), 133 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 134 collector_type_running_(kCollectorTypeNone), 135 last_gc_type_(collector::kGcTypeNone), 136 next_gc_type_(collector::kGcTypePartial), 137 capacity_(capacity), 138 growth_limit_(growth_limit), 139 max_allowed_footprint_(initial_size), 140 native_footprint_gc_watermark_(initial_size), 141 native_need_to_run_finalization_(false), 142 // Initially assume we perceive jank in case the process state is never updated. 143 process_state_(kProcessStateJankPerceptible), 144 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 145 total_bytes_freed_ever_(0), 146 total_objects_freed_ever_(0), 147 num_bytes_allocated_(0), 148 native_bytes_allocated_(0), 149 verify_missing_card_marks_(false), 150 verify_system_weaks_(false), 151 verify_pre_gc_heap_(verify_pre_gc_heap), 152 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 153 verify_post_gc_heap_(verify_post_gc_heap), 154 verify_mod_union_table_(false), 155 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 156 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 157 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 158 last_gc_time_ns_(NanoTime()), 159 allocation_rate_(0), 160 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 161 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 162 * verification is enabled, we limit the size of allocation stacks to speed up their 163 * searching. 164 */ 165 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 166 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 167 current_allocator_(kAllocatorTypeDlMalloc), 168 current_non_moving_allocator_(kAllocatorTypeNonMoving), 169 bump_pointer_space_(nullptr), 170 temp_space_(nullptr), 171 min_free_(min_free), 172 max_free_(max_free), 173 target_utilization_(target_utilization), 174 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 175 total_wait_time_(0), 176 total_allocation_time_(0), 177 verify_object_mode_(kVerifyObjectModeDisabled), 178 disable_moving_gc_count_(0), 179 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 180 use_tlab_(use_tlab), 181 main_space_backup_(nullptr), 182 min_interval_homogeneous_space_compaction_by_oom_( 183 min_interval_homogeneous_space_compaction_by_oom), 184 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 185 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 186 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 187 LOG(INFO) << "Heap() entering"; 188 } 189 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 190 // entrypoints. 191 const bool is_zygote = Runtime::Current()->IsZygote(); 192 if (!is_zygote) { 193 large_object_threshold_ = kDefaultLargeObjectThreshold; 194 // Background compaction is currently not supported for command line runs. 195 if (background_collector_type_ != foreground_collector_type_) { 196 VLOG(heap) << "Disabling background compaction for non zygote"; 197 background_collector_type_ = foreground_collector_type_; 198 } 199 } 200 ChangeCollector(desired_collector_type_); 201 live_bitmap_.reset(new accounting::HeapBitmap(this)); 202 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 203 // Requested begin for the alloc space, to follow the mapped image and oat files 204 byte* requested_alloc_space_begin = nullptr; 205 if (!image_file_name.empty()) { 206 std::string error_msg; 207 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 208 image_instruction_set, 209 &error_msg); 210 if (image_space != nullptr) { 211 AddSpace(image_space); 212 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 213 // isn't going to get in the middle 214 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 215 CHECK_GT(oat_file_end_addr, image_space->End()); 216 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 217 } else { 218 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 219 << "Attempting to fall back to imageless running. Error was: " << error_msg; 220 } 221 } 222 /* 223 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 224 +- nonmoving space (non_moving_space_capacity)+- 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 226 +-????????????????????????????????????????????+- 227 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 228 +-main alloc space / bump space 1 (capacity_) +- 229 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 230 +-????????????????????????????????????????????+- 231 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 232 +-main alloc space2 / bump space 2 (capacity_)+- 233 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 234 */ 235 bool support_homogeneous_space_compaction = 236 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 237 use_homogeneous_space_compaction_for_oom; 238 // We may use the same space the main space for the non moving space if we don't need to compact 239 // from the main space. 240 // This is not the case if we support homogeneous compaction or have a moving background 241 // collector type. 242 bool separate_non_moving_space = is_zygote || 243 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 244 IsMovingGc(background_collector_type_); 245 if (foreground_collector_type == kCollectorTypeGSS) { 246 separate_non_moving_space = false; 247 } 248 std::unique_ptr<MemMap> main_mem_map_1; 249 std::unique_ptr<MemMap> main_mem_map_2; 250 byte* request_begin = requested_alloc_space_begin; 251 if (request_begin != nullptr && separate_non_moving_space) { 252 request_begin += non_moving_space_capacity; 253 } 254 std::string error_str; 255 std::unique_ptr<MemMap> non_moving_space_mem_map; 256 if (separate_non_moving_space) { 257 // Reserve the non moving mem map before the other two since it needs to be at a specific 258 // address. 259 non_moving_space_mem_map.reset( 260 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 261 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 262 CHECK(non_moving_space_mem_map != nullptr) << error_str; 263 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 264 request_begin = reinterpret_cast<byte*>(0x1000000); 265 } 266 // Attempt to create 2 mem maps at or after the requested begin. 267 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 268 PROT_READ | PROT_WRITE, &error_str)); 269 CHECK(main_mem_map_1.get() != nullptr) << error_str; 270 if (support_homogeneous_space_compaction || 271 background_collector_type_ == kCollectorTypeSS || 272 foreground_collector_type_ == kCollectorTypeSS) { 273 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 274 capacity_, PROT_READ | PROT_WRITE, 275 &error_str)); 276 CHECK(main_mem_map_2.get() != nullptr) << error_str; 277 } 278 // Create the non moving space first so that bitmaps don't take up the address range. 279 if (separate_non_moving_space) { 280 // Non moving space is always dlmalloc since we currently don't have support for multiple 281 // active rosalloc spaces. 282 const size_t size = non_moving_space_mem_map->Size(); 283 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 284 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 285 initial_size, size, size, false); 286 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 287 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 288 << requested_alloc_space_begin; 289 AddSpace(non_moving_space_); 290 } 291 // Create other spaces based on whether or not we have a moving GC. 292 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 293 // Create bump pointer spaces. 294 // We only to create the bump pointer if the foreground collector is a compacting GC. 295 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 296 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 297 main_mem_map_1.release()); 298 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 299 AddSpace(bump_pointer_space_); 300 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 301 main_mem_map_2.release()); 302 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 303 AddSpace(temp_space_); 304 CHECK(separate_non_moving_space); 305 } else { 306 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 307 CHECK(main_space_ != nullptr); 308 AddSpace(main_space_); 309 if (!separate_non_moving_space) { 310 non_moving_space_ = main_space_; 311 CHECK(!non_moving_space_->CanMoveObjects()); 312 } 313 if (foreground_collector_type_ == kCollectorTypeGSS) { 314 CHECK_EQ(foreground_collector_type_, background_collector_type_); 315 // Create bump pointer spaces instead of a backup space. 316 main_mem_map_2.release(); 317 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 318 kGSSBumpPointerSpaceCapacity, nullptr); 319 CHECK(bump_pointer_space_ != nullptr); 320 AddSpace(bump_pointer_space_); 321 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 322 kGSSBumpPointerSpaceCapacity, nullptr); 323 CHECK(temp_space_ != nullptr); 324 AddSpace(temp_space_); 325 } else if (main_mem_map_2.get() != nullptr) { 326 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 327 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 328 growth_limit_, capacity_, name, true)); 329 CHECK(main_space_backup_.get() != nullptr); 330 // Add the space so its accounted for in the heap_begin and heap_end. 331 AddSpace(main_space_backup_.get()); 332 } 333 } 334 CHECK(non_moving_space_ != nullptr); 335 CHECK(!non_moving_space_->CanMoveObjects()); 336 // Allocate the large object space. 337 if (kUseFreeListSpaceForLOS) { 338 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 339 } else { 340 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 341 } 342 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 343 AddSpace(large_object_space_); 344 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 345 CHECK(!continuous_spaces_.empty()); 346 // Relies on the spaces being sorted. 347 byte* heap_begin = continuous_spaces_.front()->Begin(); 348 byte* heap_end = continuous_spaces_.back()->Limit(); 349 size_t heap_capacity = heap_end - heap_begin; 350 // Remove the main backup space since it slows down the GC to have unused extra spaces. 351 if (main_space_backup_.get() != nullptr) { 352 RemoveSpace(main_space_backup_.get()); 353 } 354 // Allocate the card table. 355 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 356 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 357 // Card cache for now since it makes it easier for us to update the references to the copying 358 // spaces. 359 accounting::ModUnionTable* mod_union_table = 360 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 361 GetImageSpace()); 362 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 363 AddModUnionTable(mod_union_table); 364 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 365 accounting::RememberedSet* non_moving_space_rem_set = 366 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 367 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 368 AddRememberedSet(non_moving_space_rem_set); 369 } 370 // TODO: Count objects in the image space here? 371 num_bytes_allocated_.StoreRelaxed(0); 372 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 373 kDefaultMarkStackSize)); 374 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 375 allocation_stack_.reset(accounting::ObjectStack::Create( 376 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 377 live_stack_.reset(accounting::ObjectStack::Create( 378 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 379 // It's still too early to take a lock because there are no threads yet, but we can create locks 380 // now. We don't create it earlier to make it clear that you can't use locks during heap 381 // initialization. 382 gc_complete_lock_ = new Mutex("GC complete lock"); 383 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 384 *gc_complete_lock_)); 385 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 386 last_gc_size_ = GetBytesAllocated(); 387 if (ignore_max_footprint_) { 388 SetIdealFootprint(std::numeric_limits<size_t>::max()); 389 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 390 } 391 CHECK_NE(max_allowed_footprint_, 0U); 392 // Create our garbage collectors. 393 for (size_t i = 0; i < 2; ++i) { 394 const bool concurrent = i != 0; 395 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 396 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 397 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 398 } 399 if (kMovingCollector) { 400 // TODO: Clean this up. 401 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 402 semi_space_collector_ = new collector::SemiSpace(this, generational, 403 generational ? "generational" : ""); 404 garbage_collectors_.push_back(semi_space_collector_); 405 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 406 garbage_collectors_.push_back(concurrent_copying_collector_); 407 mark_compact_collector_ = new collector::MarkCompact(this); 408 garbage_collectors_.push_back(mark_compact_collector_); 409 } 410 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr) { 411 // Check that there's no gap between the image space and the non moving space so that the 412 // immune region won't break (eg. due to a large object allocated in the gap). 413 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 414 non_moving_space_->GetMemMap()); 415 if (!no_gap) { 416 MemMap::DumpMaps(LOG(ERROR)); 417 LOG(FATAL) << "There's a gap between the image space and the main space"; 418 } 419 } 420 if (running_on_valgrind_) { 421 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 422 } 423 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 424 LOG(INFO) << "Heap() exiting"; 425 } 426} 427 428MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 429 int prot_flags, std::string* out_error_str) { 430 while (true) { 431 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 432 PROT_READ | PROT_WRITE, true, out_error_str); 433 if (map != nullptr || request_begin == nullptr) { 434 return map; 435 } 436 // Retry a second time with no specified request begin. 437 request_begin = nullptr; 438 } 439 return nullptr; 440} 441 442space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 443 size_t growth_limit, size_t capacity, 444 const char* name, bool can_move_objects) { 445 space::MallocSpace* malloc_space = nullptr; 446 if (kUseRosAlloc) { 447 // Create rosalloc space. 448 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 449 initial_size, growth_limit, capacity, 450 low_memory_mode_, can_move_objects); 451 } else { 452 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 453 initial_size, growth_limit, capacity, 454 can_move_objects); 455 } 456 if (collector::SemiSpace::kUseRememberedSet) { 457 accounting::RememberedSet* rem_set = 458 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 459 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 460 AddRememberedSet(rem_set); 461 } 462 CHECK(malloc_space != nullptr) << "Failed to create " << name; 463 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 464 return malloc_space; 465} 466 467void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 468 size_t capacity) { 469 // Is background compaction is enabled? 470 bool can_move_objects = IsMovingGc(background_collector_type_) != 471 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 472 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 473 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 474 // from the main space to the zygote space. If background compaction is enabled, always pass in 475 // that we can move objets. 476 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 477 // After the zygote we want this to be false if we don't have background compaction enabled so 478 // that getting primitive array elements is faster. 479 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 480 can_move_objects = !have_zygote_space_ && foreground_collector_type_ != kCollectorTypeGSS; 481 } 482 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 483 RemoveRememberedSet(main_space_); 484 } 485 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 486 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 487 can_move_objects); 488 SetSpaceAsDefault(main_space_); 489 VLOG(heap) << "Created main space " << main_space_; 490} 491 492void Heap::ChangeAllocator(AllocatorType allocator) { 493 if (current_allocator_ != allocator) { 494 // These two allocators are only used internally and don't have any entrypoints. 495 CHECK_NE(allocator, kAllocatorTypeLOS); 496 CHECK_NE(allocator, kAllocatorTypeNonMoving); 497 current_allocator_ = allocator; 498 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 499 SetQuickAllocEntryPointsAllocator(current_allocator_); 500 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 501 } 502} 503 504void Heap::DisableMovingGc() { 505 if (IsMovingGc(foreground_collector_type_)) { 506 foreground_collector_type_ = kCollectorTypeCMS; 507 } 508 if (IsMovingGc(background_collector_type_)) { 509 background_collector_type_ = foreground_collector_type_; 510 } 511 TransitionCollector(foreground_collector_type_); 512 ThreadList* tl = Runtime::Current()->GetThreadList(); 513 Thread* self = Thread::Current(); 514 ScopedThreadStateChange tsc(self, kSuspended); 515 tl->SuspendAll(); 516 // Something may have caused the transition to fail. 517 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 518 CHECK(main_space_ != nullptr); 519 // The allocation stack may have non movable objects in it. We need to flush it since the GC 520 // can't only handle marking allocation stack objects of one non moving space and one main 521 // space. 522 { 523 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 524 FlushAllocStack(); 525 } 526 main_space_->DisableMovingObjects(); 527 non_moving_space_ = main_space_; 528 CHECK(!non_moving_space_->CanMoveObjects()); 529 } 530 tl->ResumeAll(); 531} 532 533std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 534 if (!IsValidContinuousSpaceObjectAddress(klass)) { 535 return StringPrintf("<non heap address klass %p>", klass); 536 } 537 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 538 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 539 std::string result("["); 540 result += SafeGetClassDescriptor(component_type); 541 return result; 542 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 543 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 544 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 545 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 546 } else { 547 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 548 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 549 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 550 } 551 const DexFile* dex_file = dex_cache->GetDexFile(); 552 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 553 if (class_def_idx == DexFile::kDexNoIndex16) { 554 return "<class def not found>"; 555 } 556 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 557 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 558 return dex_file->GetTypeDescriptor(type_id); 559 } 560} 561 562std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 563 if (obj == nullptr) { 564 return "null"; 565 } 566 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 567 if (klass == nullptr) { 568 return "(class=null)"; 569 } 570 std::string result(SafeGetClassDescriptor(klass)); 571 if (obj->IsClass()) { 572 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 573 } 574 return result; 575} 576 577void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 578 if (obj == nullptr) { 579 stream << "(obj=null)"; 580 return; 581 } 582 if (IsAligned<kObjectAlignment>(obj)) { 583 space::Space* space = nullptr; 584 // Don't use find space since it only finds spaces which actually contain objects instead of 585 // spaces which may contain objects (e.g. cleared bump pointer spaces). 586 for (const auto& cur_space : continuous_spaces_) { 587 if (cur_space->HasAddress(obj)) { 588 space = cur_space; 589 break; 590 } 591 } 592 // Unprotect all the spaces. 593 for (const auto& space : continuous_spaces_) { 594 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 595 } 596 stream << "Object " << obj; 597 if (space != nullptr) { 598 stream << " in space " << *space; 599 } 600 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 601 stream << "\nclass=" << klass; 602 if (klass != nullptr) { 603 stream << " type= " << SafePrettyTypeOf(obj); 604 } 605 // Re-protect the address we faulted on. 606 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 607 } 608} 609 610bool Heap::IsCompilingBoot() const { 611 if (!Runtime::Current()->IsCompiler()) { 612 return false; 613 } 614 for (const auto& space : continuous_spaces_) { 615 if (space->IsImageSpace() || space->IsZygoteSpace()) { 616 return false; 617 } 618 } 619 return true; 620} 621 622bool Heap::HasImageSpace() const { 623 for (const auto& space : continuous_spaces_) { 624 if (space->IsImageSpace()) { 625 return true; 626 } 627 } 628 return false; 629} 630 631void Heap::IncrementDisableMovingGC(Thread* self) { 632 // Need to do this holding the lock to prevent races where the GC is about to run / running when 633 // we attempt to disable it. 634 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 635 MutexLock mu(self, *gc_complete_lock_); 636 ++disable_moving_gc_count_; 637 if (IsMovingGc(collector_type_running_)) { 638 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 639 } 640} 641 642void Heap::DecrementDisableMovingGC(Thread* self) { 643 MutexLock mu(self, *gc_complete_lock_); 644 CHECK_GE(disable_moving_gc_count_, 0U); 645 --disable_moving_gc_count_; 646} 647 648void Heap::UpdateProcessState(ProcessState process_state) { 649 if (process_state_ != process_state) { 650 process_state_ = process_state; 651 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 652 // Start at index 1 to avoid "is always false" warning. 653 // Have iteration 1 always transition the collector. 654 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 655 ? foreground_collector_type_ : background_collector_type_); 656 usleep(kCollectorTransitionStressWait); 657 } 658 if (process_state_ == kProcessStateJankPerceptible) { 659 // Transition back to foreground right away to prevent jank. 660 RequestCollectorTransition(foreground_collector_type_, 0); 661 } else { 662 // Don't delay for debug builds since we may want to stress test the GC. 663 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 664 // special handling which does a homogenous space compaction once but then doesn't transition 665 // the collector. 666 RequestCollectorTransition(background_collector_type_, 667 kIsDebugBuild ? 0 : kCollectorTransitionWait); 668 } 669 } 670} 671 672void Heap::CreateThreadPool() { 673 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 674 if (num_threads != 0) { 675 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 676 } 677} 678 679void Heap::VisitObjects(ObjectCallback callback, void* arg) { 680 Thread* self = Thread::Current(); 681 // GCs can move objects, so don't allow this. 682 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 683 if (bump_pointer_space_ != nullptr) { 684 // Visit objects in bump pointer space. 685 bump_pointer_space_->Walk(callback, arg); 686 } 687 // TODO: Switch to standard begin and end to use ranged a based loop. 688 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 689 it < end; ++it) { 690 mirror::Object* obj = *it; 691 if (obj != nullptr && obj->GetClass() != nullptr) { 692 // Avoid the race condition caused by the object not yet being written into the allocation 693 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 694 // there can be nulls on the allocation stack. 695 callback(obj, arg); 696 } 697 } 698 GetLiveBitmap()->Walk(callback, arg); 699 self->EndAssertNoThreadSuspension(old_cause); 700} 701 702void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 703 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 704 space::ContinuousSpace* space2 = non_moving_space_; 705 // TODO: Generalize this to n bitmaps? 706 CHECK(space1 != nullptr); 707 CHECK(space2 != nullptr); 708 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 709 large_object_space_->GetLiveBitmap(), stack); 710} 711 712void Heap::DeleteThreadPool() { 713 thread_pool_.reset(nullptr); 714} 715 716void Heap::AddSpace(space::Space* space) { 717 CHECK(space != nullptr); 718 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 719 if (space->IsContinuousSpace()) { 720 DCHECK(!space->IsDiscontinuousSpace()); 721 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 722 // Continuous spaces don't necessarily have bitmaps. 723 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 724 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 725 if (live_bitmap != nullptr) { 726 CHECK(mark_bitmap != nullptr); 727 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 728 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 729 } 730 continuous_spaces_.push_back(continuous_space); 731 // Ensure that spaces remain sorted in increasing order of start address. 732 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 733 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 734 return a->Begin() < b->Begin(); 735 }); 736 } else { 737 CHECK(space->IsDiscontinuousSpace()); 738 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 739 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 740 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 741 discontinuous_spaces_.push_back(discontinuous_space); 742 } 743 if (space->IsAllocSpace()) { 744 alloc_spaces_.push_back(space->AsAllocSpace()); 745 } 746} 747 748void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 749 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 750 if (continuous_space->IsDlMallocSpace()) { 751 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 752 } else if (continuous_space->IsRosAllocSpace()) { 753 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 754 } 755} 756 757void Heap::RemoveSpace(space::Space* space) { 758 DCHECK(space != nullptr); 759 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 760 if (space->IsContinuousSpace()) { 761 DCHECK(!space->IsDiscontinuousSpace()); 762 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 763 // Continuous spaces don't necessarily have bitmaps. 764 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 765 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 766 if (live_bitmap != nullptr) { 767 DCHECK(mark_bitmap != nullptr); 768 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 769 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 770 } 771 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 772 DCHECK(it != continuous_spaces_.end()); 773 continuous_spaces_.erase(it); 774 } else { 775 DCHECK(space->IsDiscontinuousSpace()); 776 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 777 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 778 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 779 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 780 discontinuous_space); 781 DCHECK(it != discontinuous_spaces_.end()); 782 discontinuous_spaces_.erase(it); 783 } 784 if (space->IsAllocSpace()) { 785 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 786 DCHECK(it != alloc_spaces_.end()); 787 alloc_spaces_.erase(it); 788 } 789} 790 791void Heap::DumpGcPerformanceInfo(std::ostream& os) { 792 // Dump cumulative timings. 793 os << "Dumping cumulative Gc timings\n"; 794 uint64_t total_duration = 0; 795 // Dump cumulative loggers for each GC type. 796 uint64_t total_paused_time = 0; 797 for (auto& collector : garbage_collectors_) { 798 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 799 const size_t iterations = logger.GetIterations(); 800 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 801 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 802 os << ConstDumpable<CumulativeLogger>(logger); 803 const uint64_t total_ns = logger.GetTotalNs(); 804 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 805 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 806 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 807 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 808 Histogram<uint64_t>::CumulativeData cumulative_data; 809 pause_histogram.CreateHistogram(&cumulative_data); 810 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 811 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 812 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 813 << collector->GetName() << " freed: " << freed_objects 814 << " objects with total size " << PrettySize(freed_bytes) << "\n" 815 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 816 << PrettySize(freed_bytes / seconds) << "/s\n"; 817 total_duration += total_ns; 818 total_paused_time += total_pause_ns; 819 } 820 collector->ResetMeasurements(); 821 } 822 uint64_t allocation_time = 823 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 824 if (total_duration != 0) { 825 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 826 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 827 os << "Mean GC size throughput: " 828 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 829 os << "Mean GC object throughput: " 830 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 831 } 832 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 833 os << "Total number of allocations " << total_objects_allocated << "\n"; 834 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 835 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 836 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 837 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 838 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 839 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 840 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 841 if (kMeasureAllocationTime) { 842 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 843 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 844 << "\n"; 845 } 846 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 847 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 848 BaseMutex::DumpAll(os); 849} 850 851Heap::~Heap() { 852 VLOG(heap) << "Starting ~Heap()"; 853 STLDeleteElements(&garbage_collectors_); 854 // If we don't reset then the mark stack complains in its destructor. 855 allocation_stack_->Reset(); 856 live_stack_->Reset(); 857 STLDeleteValues(&mod_union_tables_); 858 STLDeleteValues(&remembered_sets_); 859 STLDeleteElements(&continuous_spaces_); 860 STLDeleteElements(&discontinuous_spaces_); 861 delete gc_complete_lock_; 862 delete heap_trim_request_lock_; 863 VLOG(heap) << "Finished ~Heap()"; 864} 865 866space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 867 bool fail_ok) const { 868 for (const auto& space : continuous_spaces_) { 869 if (space->Contains(obj)) { 870 return space; 871 } 872 } 873 if (!fail_ok) { 874 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 875 } 876 return NULL; 877} 878 879space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 880 bool fail_ok) const { 881 for (const auto& space : discontinuous_spaces_) { 882 if (space->Contains(obj)) { 883 return space; 884 } 885 } 886 if (!fail_ok) { 887 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 888 } 889 return NULL; 890} 891 892space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 893 space::Space* result = FindContinuousSpaceFromObject(obj, true); 894 if (result != NULL) { 895 return result; 896 } 897 return FindDiscontinuousSpaceFromObject(obj, true); 898} 899 900space::ImageSpace* Heap::GetImageSpace() const { 901 for (const auto& space : continuous_spaces_) { 902 if (space->IsImageSpace()) { 903 return space->AsImageSpace(); 904 } 905 } 906 return NULL; 907} 908 909void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 910 std::ostringstream oss; 911 size_t total_bytes_free = GetFreeMemory(); 912 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 913 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 914 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 915 if (total_bytes_free >= byte_count) { 916 space::AllocSpace* space = nullptr; 917 if (allocator_type == kAllocatorTypeNonMoving) { 918 space = non_moving_space_; 919 } else if (allocator_type == kAllocatorTypeRosAlloc || 920 allocator_type == kAllocatorTypeDlMalloc) { 921 space = main_space_; 922 } else if (allocator_type == kAllocatorTypeBumpPointer || 923 allocator_type == kAllocatorTypeTLAB) { 924 space = bump_pointer_space_; 925 } 926 if (space != nullptr) { 927 space->LogFragmentationAllocFailure(oss, byte_count); 928 } 929 } 930 self->ThrowOutOfMemoryError(oss.str().c_str()); 931} 932 933void Heap::DoPendingTransitionOrTrim() { 934 if (!CareAboutPauseTimes()) { 935 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 936 // about pauses. 937 Runtime* runtime = Runtime::Current(); 938 runtime->GetThreadList()->SuspendAll(); 939 uint64_t start_time = NanoTime(); 940 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 941 VLOG(heap) << "Deflating " << count << " monitors took " 942 << PrettyDuration(NanoTime() - start_time); 943 runtime->GetThreadList()->ResumeAll(); 944 } 945 if (NanoTime() - last_heap_transition_time_ > kCollectorTransitionWait) { 946 // Launch homogeneous space compaction if it is desired. 947 if (desired_collector_type_ == kCollectorTypeHomogeneousSpaceCompact) { 948 if (!CareAboutPauseTimes()) { 949 PerformHomogeneousSpaceCompact(); 950 last_heap_transition_time_ = NanoTime(); 951 } 952 desired_collector_type_ = collector_type_; 953 } else { 954 // Transition the collector if the desired collector type is not the same as the current 955 // collector type. 956 TransitionCollector(desired_collector_type_); 957 last_heap_transition_time_ = NanoTime(); 958 } 959 } 960 // Do a heap trim if it is needed. This is good to do even with hspace compaction since it may 961 // trim the native heap and dlmalloc spaces. 962 Trim(); 963} 964 965void Heap::Trim() { 966 Thread* self = Thread::Current(); 967 { 968 MutexLock mu(self, *heap_trim_request_lock_); 969 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 970 return; 971 } 972 last_trim_time_ = NanoTime(); 973 heap_trim_request_pending_ = false; 974 } 975 { 976 // Need to do this before acquiring the locks since we don't want to get suspended while 977 // holding any locks. 978 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 979 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 980 // trimming. 981 MutexLock mu(self, *gc_complete_lock_); 982 // Ensure there is only one GC at a time. 983 WaitForGcToCompleteLocked(kGcCauseTrim, self); 984 collector_type_running_ = kCollectorTypeHeapTrim; 985 } 986 uint64_t start_ns = NanoTime(); 987 // Trim the managed spaces. 988 uint64_t total_alloc_space_allocated = 0; 989 uint64_t total_alloc_space_size = 0; 990 uint64_t managed_reclaimed = 0; 991 for (const auto& space : continuous_spaces_) { 992 if (space->IsMallocSpace()) { 993 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 994 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 995 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 996 // for a long period of time. 997 managed_reclaimed += malloc_space->Trim(); 998 } 999 total_alloc_space_size += malloc_space->Size(); 1000 } 1001 } 1002 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 1003 if (bump_pointer_space_ != nullptr) { 1004 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1005 } 1006 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1007 static_cast<float>(total_alloc_space_size); 1008 uint64_t gc_heap_end_ns = NanoTime(); 1009 // We never move things in the native heap, so we can finish the GC at this point. 1010 FinishGC(self, collector::kGcTypeNone); 1011 size_t native_reclaimed = 0; 1012 // Only trim the native heap if we don't care about pauses. 1013 if (!CareAboutPauseTimes()) { 1014#if defined(USE_DLMALLOC) 1015 // Trim the native heap. 1016 dlmalloc_trim(0); 1017 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1018#elif defined(USE_JEMALLOC) 1019 // Jemalloc does it's own internal trimming. 1020#else 1021 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1022#endif 1023 } 1024 uint64_t end_ns = NanoTime(); 1025 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1026 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1027 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1028 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1029 << "%."; 1030} 1031 1032bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1033 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1034 // taking the lock. 1035 if (obj == nullptr) { 1036 return true; 1037 } 1038 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1039} 1040 1041bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1042 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1043} 1044 1045bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1046 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1047 return false; 1048 } 1049 for (const auto& space : continuous_spaces_) { 1050 if (space->HasAddress(obj)) { 1051 return true; 1052 } 1053 } 1054 return false; 1055} 1056 1057bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1058 bool search_live_stack, bool sorted) { 1059 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1060 return false; 1061 } 1062 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1063 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1064 if (obj == klass) { 1065 // This case happens for java.lang.Class. 1066 return true; 1067 } 1068 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1069 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1070 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1071 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1072 return temp_space_->Contains(obj); 1073 } 1074 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1075 space::DiscontinuousSpace* d_space = nullptr; 1076 if (c_space != nullptr) { 1077 if (c_space->GetLiveBitmap()->Test(obj)) { 1078 return true; 1079 } 1080 } else { 1081 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1082 if (d_space != nullptr) { 1083 if (d_space->GetLiveBitmap()->Test(obj)) { 1084 return true; 1085 } 1086 } 1087 } 1088 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1089 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1090 if (i > 0) { 1091 NanoSleep(MsToNs(10)); 1092 } 1093 if (search_allocation_stack) { 1094 if (sorted) { 1095 if (allocation_stack_->ContainsSorted(obj)) { 1096 return true; 1097 } 1098 } else if (allocation_stack_->Contains(obj)) { 1099 return true; 1100 } 1101 } 1102 1103 if (search_live_stack) { 1104 if (sorted) { 1105 if (live_stack_->ContainsSorted(obj)) { 1106 return true; 1107 } 1108 } else if (live_stack_->Contains(obj)) { 1109 return true; 1110 } 1111 } 1112 } 1113 // We need to check the bitmaps again since there is a race where we mark something as live and 1114 // then clear the stack containing it. 1115 if (c_space != nullptr) { 1116 if (c_space->GetLiveBitmap()->Test(obj)) { 1117 return true; 1118 } 1119 } else { 1120 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1121 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1122 return true; 1123 } 1124 } 1125 return false; 1126} 1127 1128std::string Heap::DumpSpaces() const { 1129 std::ostringstream oss; 1130 DumpSpaces(oss); 1131 return oss.str(); 1132} 1133 1134void Heap::DumpSpaces(std::ostream& stream) const { 1135 for (const auto& space : continuous_spaces_) { 1136 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1137 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1138 stream << space << " " << *space << "\n"; 1139 if (live_bitmap != nullptr) { 1140 stream << live_bitmap << " " << *live_bitmap << "\n"; 1141 } 1142 if (mark_bitmap != nullptr) { 1143 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1144 } 1145 } 1146 for (const auto& space : discontinuous_spaces_) { 1147 stream << space << " " << *space << "\n"; 1148 } 1149} 1150 1151void Heap::VerifyObjectBody(mirror::Object* obj) { 1152 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1153 return; 1154 } 1155 1156 // Ignore early dawn of the universe verifications. 1157 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1158 return; 1159 } 1160 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1161 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1162 CHECK(c != nullptr) << "Null class in object " << obj; 1163 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1164 CHECK(VerifyClassClass(c)); 1165 1166 if (verify_object_mode_ > kVerifyObjectModeFast) { 1167 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1168 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1169 } 1170} 1171 1172void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1173 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1174} 1175 1176void Heap::VerifyHeap() { 1177 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1178 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1179} 1180 1181void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1182 // Use signed comparison since freed bytes can be negative when background compaction foreground 1183 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1184 // free list backed space typically increasing memory footprint due to padding and binning. 1185 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1186 // Note: This relies on 2s complement for handling negative freed_bytes. 1187 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1188 if (Runtime::Current()->HasStatsEnabled()) { 1189 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1190 thread_stats->freed_objects += freed_objects; 1191 thread_stats->freed_bytes += freed_bytes; 1192 // TODO: Do this concurrently. 1193 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1194 global_stats->freed_objects += freed_objects; 1195 global_stats->freed_bytes += freed_bytes; 1196 } 1197} 1198 1199space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1200 for (const auto& space : continuous_spaces_) { 1201 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1202 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1203 return space->AsContinuousSpace()->AsRosAllocSpace(); 1204 } 1205 } 1206 } 1207 return nullptr; 1208} 1209 1210mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1211 size_t alloc_size, size_t* bytes_allocated, 1212 size_t* usable_size, 1213 mirror::Class** klass) { 1214 bool was_default_allocator = allocator == GetCurrentAllocator(); 1215 // Make sure there is no pending exception since we may need to throw an OOME. 1216 self->AssertNoPendingException(); 1217 DCHECK(klass != nullptr); 1218 StackHandleScope<1> hs(self); 1219 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1220 klass = nullptr; // Invalidate for safety. 1221 // The allocation failed. If the GC is running, block until it completes, and then retry the 1222 // allocation. 1223 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1224 if (last_gc != collector::kGcTypeNone) { 1225 // If we were the default allocator but the allocator changed while we were suspended, 1226 // abort the allocation. 1227 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1228 return nullptr; 1229 } 1230 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1231 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1232 usable_size); 1233 if (ptr != nullptr) { 1234 return ptr; 1235 } 1236 } 1237 1238 collector::GcType tried_type = next_gc_type_; 1239 const bool gc_ran = 1240 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1241 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1242 return nullptr; 1243 } 1244 if (gc_ran) { 1245 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1246 usable_size); 1247 if (ptr != nullptr) { 1248 return ptr; 1249 } 1250 } 1251 1252 // Loop through our different Gc types and try to Gc until we get enough free memory. 1253 for (collector::GcType gc_type : gc_plan_) { 1254 if (gc_type == tried_type) { 1255 continue; 1256 } 1257 // Attempt to run the collector, if we succeed, re-try the allocation. 1258 const bool gc_ran = 1259 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1260 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1261 return nullptr; 1262 } 1263 if (gc_ran) { 1264 // Did we free sufficient memory for the allocation to succeed? 1265 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1266 usable_size); 1267 if (ptr != nullptr) { 1268 return ptr; 1269 } 1270 } 1271 } 1272 // Allocations have failed after GCs; this is an exceptional state. 1273 // Try harder, growing the heap if necessary. 1274 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1275 usable_size); 1276 if (ptr != nullptr) { 1277 return ptr; 1278 } 1279 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1280 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1281 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1282 // OOME. 1283 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1284 << " allocation"; 1285 // TODO: Run finalization, but this may cause more allocations to occur. 1286 // We don't need a WaitForGcToComplete here either. 1287 DCHECK(!gc_plan_.empty()); 1288 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1289 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1290 return nullptr; 1291 } 1292 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1293 if (ptr == nullptr) { 1294 const uint64_t current_time = NanoTime(); 1295 switch (allocator) { 1296 case kAllocatorTypeRosAlloc: 1297 // Fall-through. 1298 case kAllocatorTypeDlMalloc: { 1299 if (use_homogeneous_space_compaction_for_oom_ && 1300 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1301 min_interval_homogeneous_space_compaction_by_oom_) { 1302 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1303 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1304 switch (result) { 1305 case HomogeneousSpaceCompactResult::kSuccess: 1306 // If the allocation succeeded, we delayed an oom. 1307 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1308 usable_size); 1309 if (ptr != nullptr) { 1310 count_delayed_oom_++; 1311 } 1312 break; 1313 case HomogeneousSpaceCompactResult::kErrorReject: 1314 // Reject due to disabled moving GC. 1315 break; 1316 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1317 // Throw OOM by default. 1318 break; 1319 default: { 1320 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1321 << static_cast<size_t>(result); 1322 } 1323 } 1324 // Always print that we ran homogeneous space compation since this can cause jank. 1325 VLOG(heap) << "Ran heap homogeneous space compaction, " 1326 << " requested defragmentation " 1327 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1328 << " performed defragmentation " 1329 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1330 << " ignored homogeneous space compaction " 1331 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1332 << " delayed count = " 1333 << count_delayed_oom_.LoadSequentiallyConsistent(); 1334 } 1335 break; 1336 } 1337 case kAllocatorTypeNonMoving: { 1338 // Try to transition the heap if the allocation failure was due to the space being full. 1339 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1340 // If we aren't out of memory then the OOM was probably from the non moving space being 1341 // full. Attempt to disable compaction and turn the main space into a non moving space. 1342 DisableMovingGc(); 1343 // If we are still a moving GC then something must have caused the transition to fail. 1344 if (IsMovingGc(collector_type_)) { 1345 MutexLock mu(self, *gc_complete_lock_); 1346 // If we couldn't disable moving GC, just throw OOME and return null. 1347 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1348 << disable_moving_gc_count_; 1349 } else { 1350 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1351 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1352 usable_size); 1353 } 1354 } 1355 break; 1356 } 1357 default: { 1358 // Do nothing for others allocators. 1359 } 1360 } 1361 } 1362 // If the allocation hasn't succeeded by this point, throw an OOM error. 1363 if (ptr == nullptr) { 1364 ThrowOutOfMemoryError(self, alloc_size, allocator); 1365 } 1366 return ptr; 1367} 1368 1369void Heap::SetTargetHeapUtilization(float target) { 1370 DCHECK_GT(target, 0.0f); // asserted in Java code 1371 DCHECK_LT(target, 1.0f); 1372 target_utilization_ = target; 1373} 1374 1375size_t Heap::GetObjectsAllocated() const { 1376 size_t total = 0; 1377 for (space::AllocSpace* space : alloc_spaces_) { 1378 total += space->GetObjectsAllocated(); 1379 } 1380 return total; 1381} 1382 1383uint64_t Heap::GetObjectsAllocatedEver() const { 1384 return GetObjectsFreedEver() + GetObjectsAllocated(); 1385} 1386 1387uint64_t Heap::GetBytesAllocatedEver() const { 1388 return GetBytesFreedEver() + GetBytesAllocated(); 1389} 1390 1391class InstanceCounter { 1392 public: 1393 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1394 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1395 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1396 } 1397 static void Callback(mirror::Object* obj, void* arg) 1398 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1399 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1400 mirror::Class* instance_class = obj->GetClass(); 1401 CHECK(instance_class != nullptr); 1402 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1403 if (instance_counter->use_is_assignable_from_) { 1404 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1405 ++instance_counter->counts_[i]; 1406 } 1407 } else if (instance_class == instance_counter->classes_[i]) { 1408 ++instance_counter->counts_[i]; 1409 } 1410 } 1411 } 1412 1413 private: 1414 const std::vector<mirror::Class*>& classes_; 1415 bool use_is_assignable_from_; 1416 uint64_t* const counts_; 1417 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1418}; 1419 1420void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1421 uint64_t* counts) { 1422 // Can't do any GC in this function since this may move classes. 1423 Thread* self = Thread::Current(); 1424 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1425 InstanceCounter counter(classes, use_is_assignable_from, counts); 1426 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1427 VisitObjects(InstanceCounter::Callback, &counter); 1428 self->EndAssertNoThreadSuspension(old_cause); 1429} 1430 1431class InstanceCollector { 1432 public: 1433 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1434 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1435 : class_(c), max_count_(max_count), instances_(instances) { 1436 } 1437 static void Callback(mirror::Object* obj, void* arg) 1438 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1439 DCHECK(arg != nullptr); 1440 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1441 mirror::Class* instance_class = obj->GetClass(); 1442 if (instance_class == instance_collector->class_) { 1443 if (instance_collector->max_count_ == 0 || 1444 instance_collector->instances_.size() < instance_collector->max_count_) { 1445 instance_collector->instances_.push_back(obj); 1446 } 1447 } 1448 } 1449 1450 private: 1451 mirror::Class* class_; 1452 uint32_t max_count_; 1453 std::vector<mirror::Object*>& instances_; 1454 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1455}; 1456 1457void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1458 std::vector<mirror::Object*>& instances) { 1459 // Can't do any GC in this function since this may move classes. 1460 Thread* self = Thread::Current(); 1461 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1462 InstanceCollector collector(c, max_count, instances); 1463 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1464 VisitObjects(&InstanceCollector::Callback, &collector); 1465 self->EndAssertNoThreadSuspension(old_cause); 1466} 1467 1468class ReferringObjectsFinder { 1469 public: 1470 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1471 std::vector<mirror::Object*>& referring_objects) 1472 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1473 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1474 } 1475 1476 static void Callback(mirror::Object* obj, void* arg) 1477 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1478 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1479 } 1480 1481 // For bitmap Visit. 1482 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1483 // annotalysis on visitors. 1484 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1485 o->VisitReferences<true>(*this, VoidFunctor()); 1486 } 1487 1488 // For Object::VisitReferences. 1489 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1490 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1491 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1492 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1493 referring_objects_.push_back(obj); 1494 } 1495 } 1496 1497 private: 1498 mirror::Object* object_; 1499 uint32_t max_count_; 1500 std::vector<mirror::Object*>& referring_objects_; 1501 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1502}; 1503 1504void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1505 std::vector<mirror::Object*>& referring_objects) { 1506 // Can't do any GC in this function since this may move the object o. 1507 Thread* self = Thread::Current(); 1508 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1509 ReferringObjectsFinder finder(o, max_count, referring_objects); 1510 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1511 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1512 self->EndAssertNoThreadSuspension(old_cause); 1513} 1514 1515void Heap::CollectGarbage(bool clear_soft_references) { 1516 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1517 // last GC will not have necessarily been cleared. 1518 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1519} 1520 1521HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1522 Thread* self = Thread::Current(); 1523 // Inc requested homogeneous space compaction. 1524 count_requested_homogeneous_space_compaction_++; 1525 // Store performed homogeneous space compaction at a new request arrival. 1526 ThreadList* tl = Runtime::Current()->GetThreadList(); 1527 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1528 Locks::mutator_lock_->AssertNotHeld(self); 1529 { 1530 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1531 MutexLock mu(self, *gc_complete_lock_); 1532 // Ensure there is only one GC at a time. 1533 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1534 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1535 // is non zero. 1536 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1537 // exit. 1538 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1539 !main_space_->CanMoveObjects()) { 1540 return HomogeneousSpaceCompactResult::kErrorReject; 1541 } 1542 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1543 } 1544 if (Runtime::Current()->IsShuttingDown(self)) { 1545 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1546 // cause objects to get finalized. 1547 FinishGC(self, collector::kGcTypeNone); 1548 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1549 } 1550 // Suspend all threads. 1551 tl->SuspendAll(); 1552 uint64_t start_time = NanoTime(); 1553 // Launch compaction. 1554 space::MallocSpace* to_space = main_space_backup_.release(); 1555 space::MallocSpace* from_space = main_space_; 1556 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1557 const uint64_t space_size_before_compaction = from_space->Size(); 1558 AddSpace(to_space); 1559 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1560 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1561 from_space->GetMemMap()->Protect(PROT_READ); 1562 const uint64_t space_size_after_compaction = to_space->Size(); 1563 main_space_ = to_space; 1564 main_space_backup_.reset(from_space); 1565 RemoveSpace(from_space); 1566 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1567 // Update performed homogeneous space compaction count. 1568 count_performed_homogeneous_space_compaction_++; 1569 // Print statics log and resume all threads. 1570 uint64_t duration = NanoTime() - start_time; 1571 VLOG(heap) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1572 << PrettySize(space_size_before_compaction) << " -> " 1573 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1574 << std::fixed << static_cast<double>(space_size_after_compaction) / 1575 static_cast<double>(space_size_before_compaction); 1576 tl->ResumeAll(); 1577 // Finish GC. 1578 reference_processor_.EnqueueClearedReferences(self); 1579 GrowForUtilization(semi_space_collector_); 1580 FinishGC(self, collector::kGcTypeFull); 1581 return HomogeneousSpaceCompactResult::kSuccess; 1582} 1583 1584 1585void Heap::TransitionCollector(CollectorType collector_type) { 1586 if (collector_type == collector_type_) { 1587 return; 1588 } 1589 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1590 << " -> " << static_cast<int>(collector_type); 1591 uint64_t start_time = NanoTime(); 1592 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1593 Runtime* const runtime = Runtime::Current(); 1594 ThreadList* const tl = runtime->GetThreadList(); 1595 Thread* const self = Thread::Current(); 1596 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1597 Locks::mutator_lock_->AssertNotHeld(self); 1598 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1599 // compacting_gc_disable_count_, this should rarely occurs). 1600 for (;;) { 1601 { 1602 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1603 MutexLock mu(self, *gc_complete_lock_); 1604 // Ensure there is only one GC at a time. 1605 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1606 // Currently we only need a heap transition if we switch from a moving collector to a 1607 // non-moving one, or visa versa. 1608 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1609 // If someone else beat us to it and changed the collector before we could, exit. 1610 // This is safe to do before the suspend all since we set the collector_type_running_ before 1611 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1612 // then it would get blocked on WaitForGcToCompleteLocked. 1613 if (collector_type == collector_type_) { 1614 return; 1615 } 1616 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1617 if (!copying_transition || disable_moving_gc_count_ == 0) { 1618 // TODO: Not hard code in semi-space collector? 1619 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1620 break; 1621 } 1622 } 1623 usleep(1000); 1624 } 1625 if (runtime->IsShuttingDown(self)) { 1626 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1627 // cause objects to get finalized. 1628 FinishGC(self, collector::kGcTypeNone); 1629 return; 1630 } 1631 tl->SuspendAll(); 1632 switch (collector_type) { 1633 case kCollectorTypeSS: { 1634 if (!IsMovingGc(collector_type_)) { 1635 // Create the bump pointer space from the backup space. 1636 CHECK(main_space_backup_ != nullptr); 1637 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1638 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1639 // pointer space last transition it will be protected. 1640 CHECK(mem_map != nullptr); 1641 mem_map->Protect(PROT_READ | PROT_WRITE); 1642 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1643 mem_map.release()); 1644 AddSpace(bump_pointer_space_); 1645 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1646 // Use the now empty main space mem map for the bump pointer temp space. 1647 mem_map.reset(main_space_->ReleaseMemMap()); 1648 // Unset the pointers just in case. 1649 if (dlmalloc_space_ == main_space_) { 1650 dlmalloc_space_ = nullptr; 1651 } else if (rosalloc_space_ == main_space_) { 1652 rosalloc_space_ = nullptr; 1653 } 1654 // Remove the main space so that we don't try to trim it, this doens't work for debug 1655 // builds since RosAlloc attempts to read the magic number from a protected page. 1656 RemoveSpace(main_space_); 1657 RemoveRememberedSet(main_space_); 1658 delete main_space_; // Delete the space since it has been removed. 1659 main_space_ = nullptr; 1660 RemoveRememberedSet(main_space_backup_.get()); 1661 main_space_backup_.reset(nullptr); // Deletes the space. 1662 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1663 mem_map.release()); 1664 AddSpace(temp_space_); 1665 } 1666 break; 1667 } 1668 case kCollectorTypeMS: 1669 // Fall through. 1670 case kCollectorTypeCMS: { 1671 if (IsMovingGc(collector_type_)) { 1672 CHECK(temp_space_ != nullptr); 1673 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1674 RemoveSpace(temp_space_); 1675 temp_space_ = nullptr; 1676 mem_map->Protect(PROT_READ | PROT_WRITE); 1677 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1678 mem_map->Size()); 1679 mem_map.release(); 1680 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1681 AddSpace(main_space_); 1682 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1683 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1684 RemoveSpace(bump_pointer_space_); 1685 bump_pointer_space_ = nullptr; 1686 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1687 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1688 if (kIsDebugBuild && kUseRosAlloc) { 1689 mem_map->Protect(PROT_READ | PROT_WRITE); 1690 } 1691 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1692 mem_map->Size(), mem_map->Size(), 1693 name, true)); 1694 if (kIsDebugBuild && kUseRosAlloc) { 1695 mem_map->Protect(PROT_NONE); 1696 } 1697 mem_map.release(); 1698 } 1699 break; 1700 } 1701 default: { 1702 LOG(FATAL) << "Attempted to transition to invalid collector type " 1703 << static_cast<size_t>(collector_type); 1704 break; 1705 } 1706 } 1707 ChangeCollector(collector_type); 1708 tl->ResumeAll(); 1709 // Can't call into java code with all threads suspended. 1710 reference_processor_.EnqueueClearedReferences(self); 1711 uint64_t duration = NanoTime() - start_time; 1712 GrowForUtilization(semi_space_collector_); 1713 FinishGC(self, collector::kGcTypeFull); 1714 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1715 int32_t delta_allocated = before_allocated - after_allocated; 1716 std::string saved_str; 1717 if (delta_allocated >= 0) { 1718 saved_str = " saved at least " + PrettySize(delta_allocated); 1719 } else { 1720 saved_str = " expanded " + PrettySize(-delta_allocated); 1721 } 1722 VLOG(heap) << "Heap transition to " << process_state_ << " took " 1723 << PrettyDuration(duration) << saved_str; 1724} 1725 1726void Heap::ChangeCollector(CollectorType collector_type) { 1727 // TODO: Only do this with all mutators suspended to avoid races. 1728 if (collector_type != collector_type_) { 1729 if (collector_type == kCollectorTypeMC) { 1730 // Don't allow mark compact unless support is compiled in. 1731 CHECK(kMarkCompactSupport); 1732 } 1733 collector_type_ = collector_type; 1734 gc_plan_.clear(); 1735 switch (collector_type_) { 1736 case kCollectorTypeCC: // Fall-through. 1737 case kCollectorTypeMC: // Fall-through. 1738 case kCollectorTypeSS: // Fall-through. 1739 case kCollectorTypeGSS: { 1740 gc_plan_.push_back(collector::kGcTypeFull); 1741 if (use_tlab_) { 1742 ChangeAllocator(kAllocatorTypeTLAB); 1743 } else { 1744 ChangeAllocator(kAllocatorTypeBumpPointer); 1745 } 1746 break; 1747 } 1748 case kCollectorTypeMS: { 1749 gc_plan_.push_back(collector::kGcTypeSticky); 1750 gc_plan_.push_back(collector::kGcTypePartial); 1751 gc_plan_.push_back(collector::kGcTypeFull); 1752 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1753 break; 1754 } 1755 case kCollectorTypeCMS: { 1756 gc_plan_.push_back(collector::kGcTypeSticky); 1757 gc_plan_.push_back(collector::kGcTypePartial); 1758 gc_plan_.push_back(collector::kGcTypeFull); 1759 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1760 break; 1761 } 1762 default: { 1763 LOG(FATAL) << "Unimplemented"; 1764 } 1765 } 1766 if (IsGcConcurrent()) { 1767 concurrent_start_bytes_ = 1768 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1769 } else { 1770 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1771 } 1772 } 1773} 1774 1775// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1776class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1777 public: 1778 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1779 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1780 } 1781 1782 void BuildBins(space::ContinuousSpace* space) { 1783 bin_live_bitmap_ = space->GetLiveBitmap(); 1784 bin_mark_bitmap_ = space->GetMarkBitmap(); 1785 BinContext context; 1786 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1787 context.collector_ = this; 1788 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1789 // Note: This requires traversing the space in increasing order of object addresses. 1790 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1791 // Add the last bin which spans after the last object to the end of the space. 1792 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1793 } 1794 1795 private: 1796 struct BinContext { 1797 uintptr_t prev_; // The end of the previous object. 1798 ZygoteCompactingCollector* collector_; 1799 }; 1800 // Maps from bin sizes to locations. 1801 std::multimap<size_t, uintptr_t> bins_; 1802 // Live bitmap of the space which contains the bins. 1803 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1804 // Mark bitmap of the space which contains the bins. 1805 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1806 1807 static void Callback(mirror::Object* obj, void* arg) 1808 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1809 DCHECK(arg != nullptr); 1810 BinContext* context = reinterpret_cast<BinContext*>(arg); 1811 ZygoteCompactingCollector* collector = context->collector_; 1812 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1813 size_t bin_size = object_addr - context->prev_; 1814 // Add the bin consisting of the end of the previous object to the start of the current object. 1815 collector->AddBin(bin_size, context->prev_); 1816 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1817 } 1818 1819 void AddBin(size_t size, uintptr_t position) { 1820 if (size != 0) { 1821 bins_.insert(std::make_pair(size, position)); 1822 } 1823 } 1824 1825 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1826 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1827 // allocator. 1828 return false; 1829 } 1830 1831 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1832 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1833 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1834 mirror::Object* forward_address; 1835 // Find the smallest bin which we can move obj in. 1836 auto it = bins_.lower_bound(object_size); 1837 if (it == bins_.end()) { 1838 // No available space in the bins, place it in the target space instead (grows the zygote 1839 // space). 1840 size_t bytes_allocated; 1841 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1842 if (to_space_live_bitmap_ != nullptr) { 1843 to_space_live_bitmap_->Set(forward_address); 1844 } else { 1845 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1846 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1847 } 1848 } else { 1849 size_t size = it->first; 1850 uintptr_t pos = it->second; 1851 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1852 forward_address = reinterpret_cast<mirror::Object*>(pos); 1853 // Set the live and mark bits so that sweeping system weaks works properly. 1854 bin_live_bitmap_->Set(forward_address); 1855 bin_mark_bitmap_->Set(forward_address); 1856 DCHECK_GE(size, object_size); 1857 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1858 } 1859 // Copy the object over to its new location. 1860 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1861 if (kUseBakerOrBrooksReadBarrier) { 1862 obj->AssertReadBarrierPointer(); 1863 if (kUseBrooksReadBarrier) { 1864 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1865 forward_address->SetReadBarrierPointer(forward_address); 1866 } 1867 forward_address->AssertReadBarrierPointer(); 1868 } 1869 return forward_address; 1870 } 1871}; 1872 1873void Heap::UnBindBitmaps() { 1874 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1875 for (const auto& space : GetContinuousSpaces()) { 1876 if (space->IsContinuousMemMapAllocSpace()) { 1877 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1878 if (alloc_space->HasBoundBitmaps()) { 1879 alloc_space->UnBindBitmaps(); 1880 } 1881 } 1882 } 1883} 1884 1885void Heap::PreZygoteFork() { 1886 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1887 Thread* self = Thread::Current(); 1888 MutexLock mu(self, zygote_creation_lock_); 1889 // Try to see if we have any Zygote spaces. 1890 if (have_zygote_space_) { 1891 return; 1892 } 1893 VLOG(heap) << "Starting PreZygoteFork"; 1894 // Trim the pages at the end of the non moving space. 1895 non_moving_space_->Trim(); 1896 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1897 // there. 1898 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1899 const bool same_space = non_moving_space_ == main_space_; 1900 if (kCompactZygote) { 1901 // Can't compact if the non moving space is the same as the main space. 1902 DCHECK(semi_space_collector_ != nullptr); 1903 // Temporarily disable rosalloc verification because the zygote 1904 // compaction will mess up the rosalloc internal metadata. 1905 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1906 ZygoteCompactingCollector zygote_collector(this); 1907 zygote_collector.BuildBins(non_moving_space_); 1908 // Create a new bump pointer space which we will compact into. 1909 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1910 non_moving_space_->Limit()); 1911 // Compact the bump pointer space to a new zygote bump pointer space. 1912 bool reset_main_space = false; 1913 if (IsMovingGc(collector_type_)) { 1914 zygote_collector.SetFromSpace(bump_pointer_space_); 1915 } else { 1916 CHECK(main_space_ != nullptr); 1917 // Copy from the main space. 1918 zygote_collector.SetFromSpace(main_space_); 1919 reset_main_space = true; 1920 } 1921 zygote_collector.SetToSpace(&target_space); 1922 zygote_collector.SetSwapSemiSpaces(false); 1923 zygote_collector.Run(kGcCauseCollectorTransition, false); 1924 if (reset_main_space) { 1925 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1926 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1927 MemMap* mem_map = main_space_->ReleaseMemMap(); 1928 RemoveSpace(main_space_); 1929 space::Space* old_main_space = main_space_; 1930 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1931 delete old_main_space; 1932 AddSpace(main_space_); 1933 } else { 1934 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1935 } 1936 if (temp_space_ != nullptr) { 1937 CHECK(temp_space_->IsEmpty()); 1938 } 1939 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1940 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1941 // Update the end and write out image. 1942 non_moving_space_->SetEnd(target_space.End()); 1943 non_moving_space_->SetLimit(target_space.Limit()); 1944 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1945 } 1946 // Change the collector to the post zygote one. 1947 ChangeCollector(foreground_collector_type_); 1948 // Save the old space so that we can remove it after we complete creating the zygote space. 1949 space::MallocSpace* old_alloc_space = non_moving_space_; 1950 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1951 // the remaining available space. 1952 // Remove the old space before creating the zygote space since creating the zygote space sets 1953 // the old alloc space's bitmaps to nullptr. 1954 RemoveSpace(old_alloc_space); 1955 if (collector::SemiSpace::kUseRememberedSet) { 1956 // Sanity bound check. 1957 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1958 // Remove the remembered set for the now zygote space (the old 1959 // non-moving space). Note now that we have compacted objects into 1960 // the zygote space, the data in the remembered set is no longer 1961 // needed. The zygote space will instead have a mod-union table 1962 // from this point on. 1963 RemoveRememberedSet(old_alloc_space); 1964 } 1965 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1966 low_memory_mode_, 1967 &non_moving_space_); 1968 CHECK(!non_moving_space_->CanMoveObjects()); 1969 if (same_space) { 1970 main_space_ = non_moving_space_; 1971 SetSpaceAsDefault(main_space_); 1972 } 1973 delete old_alloc_space; 1974 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1975 AddSpace(zygote_space); 1976 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1977 AddSpace(non_moving_space_); 1978 have_zygote_space_ = true; 1979 // Enable large object space allocations. 1980 large_object_threshold_ = kDefaultLargeObjectThreshold; 1981 // Create the zygote space mod union table. 1982 accounting::ModUnionTable* mod_union_table = 1983 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1984 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1985 AddModUnionTable(mod_union_table); 1986 if (collector::SemiSpace::kUseRememberedSet) { 1987 // Add a new remembered set for the post-zygote non-moving space. 1988 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1989 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1990 non_moving_space_); 1991 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1992 << "Failed to create post-zygote non-moving space remembered set"; 1993 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1994 } 1995} 1996 1997void Heap::FlushAllocStack() { 1998 MarkAllocStackAsLive(allocation_stack_.get()); 1999 allocation_stack_->Reset(); 2000} 2001 2002void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2003 accounting::ContinuousSpaceBitmap* bitmap2, 2004 accounting::LargeObjectBitmap* large_objects, 2005 accounting::ObjectStack* stack) { 2006 DCHECK(bitmap1 != nullptr); 2007 DCHECK(bitmap2 != nullptr); 2008 mirror::Object** limit = stack->End(); 2009 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2010 const mirror::Object* obj = *it; 2011 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2012 if (bitmap1->HasAddress(obj)) { 2013 bitmap1->Set(obj); 2014 } else if (bitmap2->HasAddress(obj)) { 2015 bitmap2->Set(obj); 2016 } else { 2017 large_objects->Set(obj); 2018 } 2019 } 2020 } 2021} 2022 2023void Heap::SwapSemiSpaces() { 2024 CHECK(bump_pointer_space_ != nullptr); 2025 CHECK(temp_space_ != nullptr); 2026 std::swap(bump_pointer_space_, temp_space_); 2027} 2028 2029void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2030 space::ContinuousMemMapAllocSpace* source_space, 2031 GcCause gc_cause) { 2032 CHECK(kMovingCollector); 2033 if (target_space != source_space) { 2034 // Don't swap spaces since this isn't a typical semi space collection. 2035 semi_space_collector_->SetSwapSemiSpaces(false); 2036 semi_space_collector_->SetFromSpace(source_space); 2037 semi_space_collector_->SetToSpace(target_space); 2038 semi_space_collector_->Run(gc_cause, false); 2039 } else { 2040 CHECK(target_space->IsBumpPointerSpace()) 2041 << "In-place compaction is only supported for bump pointer spaces"; 2042 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2043 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2044 } 2045} 2046 2047collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2048 bool clear_soft_references) { 2049 Thread* self = Thread::Current(); 2050 Runtime* runtime = Runtime::Current(); 2051 // If the heap can't run the GC, silently fail and return that no GC was run. 2052 switch (gc_type) { 2053 case collector::kGcTypePartial: { 2054 if (!have_zygote_space_) { 2055 return collector::kGcTypeNone; 2056 } 2057 break; 2058 } 2059 default: { 2060 // Other GC types don't have any special cases which makes them not runnable. The main case 2061 // here is full GC. 2062 } 2063 } 2064 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2065 Locks::mutator_lock_->AssertNotHeld(self); 2066 if (self->IsHandlingStackOverflow()) { 2067 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2068 } 2069 bool compacting_gc; 2070 { 2071 gc_complete_lock_->AssertNotHeld(self); 2072 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2073 MutexLock mu(self, *gc_complete_lock_); 2074 // Ensure there is only one GC at a time. 2075 WaitForGcToCompleteLocked(gc_cause, self); 2076 compacting_gc = IsMovingGc(collector_type_); 2077 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2078 if (compacting_gc && disable_moving_gc_count_ != 0) { 2079 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2080 return collector::kGcTypeNone; 2081 } 2082 collector_type_running_ = collector_type_; 2083 } 2084 2085 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2086 ++runtime->GetStats()->gc_for_alloc_count; 2087 ++self->GetStats()->gc_for_alloc_count; 2088 } 2089 uint64_t gc_start_time_ns = NanoTime(); 2090 uint64_t gc_start_size = GetBytesAllocated(); 2091 // Approximate allocation rate in bytes / second. 2092 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2093 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2094 if (LIKELY(ms_delta != 0)) { 2095 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2096 ATRACE_INT("Allocation rate KB/s", allocation_rate_ / KB); 2097 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2098 } 2099 2100 DCHECK_LT(gc_type, collector::kGcTypeMax); 2101 DCHECK_NE(gc_type, collector::kGcTypeNone); 2102 2103 collector::GarbageCollector* collector = nullptr; 2104 // TODO: Clean this up. 2105 if (compacting_gc) { 2106 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2107 current_allocator_ == kAllocatorTypeTLAB); 2108 switch (collector_type_) { 2109 case kCollectorTypeSS: 2110 // Fall-through. 2111 case kCollectorTypeGSS: 2112 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2113 semi_space_collector_->SetToSpace(temp_space_); 2114 semi_space_collector_->SetSwapSemiSpaces(true); 2115 collector = semi_space_collector_; 2116 break; 2117 case kCollectorTypeCC: 2118 collector = concurrent_copying_collector_; 2119 break; 2120 case kCollectorTypeMC: 2121 mark_compact_collector_->SetSpace(bump_pointer_space_); 2122 collector = mark_compact_collector_; 2123 break; 2124 default: 2125 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2126 } 2127 if (collector != mark_compact_collector_) { 2128 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2129 CHECK(temp_space_->IsEmpty()); 2130 } 2131 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2132 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2133 current_allocator_ == kAllocatorTypeDlMalloc) { 2134 collector = FindCollectorByGcType(gc_type); 2135 } else { 2136 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2137 } 2138 CHECK(collector != nullptr) 2139 << "Could not find garbage collector with collector_type=" 2140 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2141 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2142 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2143 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2144 RequestHeapTrim(); 2145 // Enqueue cleared references. 2146 reference_processor_.EnqueueClearedReferences(self); 2147 // Grow the heap so that we know when to perform the next GC. 2148 GrowForUtilization(collector); 2149 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2150 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2151 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2152 // (mutator time blocked >= long_pause_log_threshold_). 2153 bool log_gc = gc_cause == kGcCauseExplicit; 2154 if (!log_gc && CareAboutPauseTimes()) { 2155 // GC for alloc pauses the allocating thread, so consider it as a pause. 2156 log_gc = duration > long_gc_log_threshold_ || 2157 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2158 for (uint64_t pause : pause_times) { 2159 log_gc = log_gc || pause >= long_pause_log_threshold_; 2160 } 2161 } 2162 if (log_gc) { 2163 const size_t percent_free = GetPercentFree(); 2164 const size_t current_heap_size = GetBytesAllocated(); 2165 const size_t total_memory = GetTotalMemory(); 2166 std::ostringstream pause_string; 2167 for (size_t i = 0; i < pause_times.size(); ++i) { 2168 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2169 << ((i != pause_times.size() - 1) ? "," : ""); 2170 } 2171 LOG(INFO) << gc_cause << " " << collector->GetName() 2172 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2173 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2174 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2175 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2176 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2177 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2178 << " total " << PrettyDuration((duration / 1000) * 1000); 2179 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2180 } 2181 FinishGC(self, gc_type); 2182 // Inform DDMS that a GC completed. 2183 Dbg::GcDidFinish(); 2184 return gc_type; 2185} 2186 2187void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2188 MutexLock mu(self, *gc_complete_lock_); 2189 collector_type_running_ = kCollectorTypeNone; 2190 if (gc_type != collector::kGcTypeNone) { 2191 last_gc_type_ = gc_type; 2192 } 2193 // Wake anyone who may have been waiting for the GC to complete. 2194 gc_complete_cond_->Broadcast(self); 2195} 2196 2197static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2198 RootType /*root_type*/) { 2199 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2200 if (*root == obj) { 2201 LOG(INFO) << "Object " << obj << " is a root"; 2202 } 2203} 2204 2205class ScanVisitor { 2206 public: 2207 void operator()(const mirror::Object* obj) const { 2208 LOG(ERROR) << "Would have rescanned object " << obj; 2209 } 2210}; 2211 2212// Verify a reference from an object. 2213class VerifyReferenceVisitor { 2214 public: 2215 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2216 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2217 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2218 2219 size_t GetFailureCount() const { 2220 return fail_count_->LoadSequentiallyConsistent(); 2221 } 2222 2223 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2224 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2225 if (verify_referent_) { 2226 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2227 } 2228 } 2229 2230 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2231 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2232 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2233 } 2234 2235 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2236 return heap_->IsLiveObjectLocked(obj, true, false, true); 2237 } 2238 2239 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2240 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2241 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2242 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2243 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2244 << " thread_id= " << thread_id << " root_type= " << root_type; 2245 } 2246 } 2247 2248 private: 2249 // TODO: Fix the no thread safety analysis. 2250 // Returns false on failure. 2251 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2252 NO_THREAD_SAFETY_ANALYSIS { 2253 if (ref == nullptr || IsLive(ref)) { 2254 // Verify that the reference is live. 2255 return true; 2256 } 2257 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2258 // Print message on only on first failure to prevent spam. 2259 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2260 } 2261 if (obj != nullptr) { 2262 // Only do this part for non roots. 2263 accounting::CardTable* card_table = heap_->GetCardTable(); 2264 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2265 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2266 byte* card_addr = card_table->CardFromAddr(obj); 2267 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2268 << offset << "\n card value = " << static_cast<int>(*card_addr); 2269 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2270 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2271 } else { 2272 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2273 } 2274 2275 // Attempt to find the class inside of the recently freed objects. 2276 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2277 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2278 space::MallocSpace* space = ref_space->AsMallocSpace(); 2279 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2280 if (ref_class != nullptr) { 2281 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2282 << PrettyClass(ref_class); 2283 } else { 2284 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2285 } 2286 } 2287 2288 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2289 ref->GetClass()->IsClass()) { 2290 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2291 } else { 2292 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2293 << ") is not a valid heap address"; 2294 } 2295 2296 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2297 void* cover_begin = card_table->AddrFromCard(card_addr); 2298 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2299 accounting::CardTable::kCardSize); 2300 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2301 << "-" << cover_end; 2302 accounting::ContinuousSpaceBitmap* bitmap = 2303 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2304 2305 if (bitmap == nullptr) { 2306 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2307 if (!VerifyClassClass(obj->GetClass())) { 2308 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2309 } 2310 } else { 2311 // Print out how the object is live. 2312 if (bitmap->Test(obj)) { 2313 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2314 } 2315 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2316 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2317 } 2318 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2319 LOG(ERROR) << "Object " << obj << " found in live stack"; 2320 } 2321 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2322 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2323 } 2324 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2325 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2326 } 2327 // Attempt to see if the card table missed the reference. 2328 ScanVisitor scan_visitor; 2329 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2330 card_table->Scan(bitmap, byte_cover_begin, 2331 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2332 } 2333 2334 // Search to see if any of the roots reference our object. 2335 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2336 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2337 2338 // Search to see if any of the roots reference our reference. 2339 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2340 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2341 } 2342 return false; 2343 } 2344 2345 Heap* const heap_; 2346 Atomic<size_t>* const fail_count_; 2347 const bool verify_referent_; 2348}; 2349 2350// Verify all references within an object, for use with HeapBitmap::Visit. 2351class VerifyObjectVisitor { 2352 public: 2353 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2354 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2355 } 2356 2357 void operator()(mirror::Object* obj) const 2358 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2359 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2360 // be live or else how did we find it in the live bitmap? 2361 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2362 // The class doesn't count as a reference but we should verify it anyways. 2363 obj->VisitReferences<true>(visitor, visitor); 2364 } 2365 2366 static void VisitCallback(mirror::Object* obj, void* arg) 2367 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2368 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2369 visitor->operator()(obj); 2370 } 2371 2372 size_t GetFailureCount() const { 2373 return fail_count_->LoadSequentiallyConsistent(); 2374 } 2375 2376 private: 2377 Heap* const heap_; 2378 Atomic<size_t>* const fail_count_; 2379 const bool verify_referent_; 2380}; 2381 2382void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2383 // Slow path, the allocation stack push back must have already failed. 2384 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2385 do { 2386 // TODO: Add handle VerifyObject. 2387 StackHandleScope<1> hs(self); 2388 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2389 // Push our object into the reserve region of the allocaiton stack. This is only required due 2390 // to heap verification requiring that roots are live (either in the live bitmap or in the 2391 // allocation stack). 2392 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2393 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2394 } while (!allocation_stack_->AtomicPushBack(*obj)); 2395} 2396 2397void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2398 // Slow path, the allocation stack push back must have already failed. 2399 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2400 mirror::Object** start_address; 2401 mirror::Object** end_address; 2402 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2403 &end_address)) { 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 // Push into the reserve allocation stack. 2412 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2413 } 2414 self->SetThreadLocalAllocationStack(start_address, end_address); 2415 // Retry on the new thread-local allocation stack. 2416 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2417} 2418 2419// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2420size_t Heap::VerifyHeapReferences(bool verify_referents) { 2421 Thread* self = Thread::Current(); 2422 Locks::mutator_lock_->AssertExclusiveHeld(self); 2423 // Lets sort our allocation stacks so that we can efficiently binary search them. 2424 allocation_stack_->Sort(); 2425 live_stack_->Sort(); 2426 // Since we sorted the allocation stack content, need to revoke all 2427 // thread-local allocation stacks. 2428 RevokeAllThreadLocalAllocationStacks(self); 2429 Atomic<size_t> fail_count_(0); 2430 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2431 // Verify objects in the allocation stack since these will be objects which were: 2432 // 1. Allocated prior to the GC (pre GC verification). 2433 // 2. Allocated during the GC (pre sweep GC verification). 2434 // We don't want to verify the objects in the live stack since they themselves may be 2435 // pointing to dead objects if they are not reachable. 2436 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2437 // Verify the roots: 2438 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2439 if (visitor.GetFailureCount() > 0) { 2440 // Dump mod-union tables. 2441 for (const auto& table_pair : mod_union_tables_) { 2442 accounting::ModUnionTable* mod_union_table = table_pair.second; 2443 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2444 } 2445 // Dump remembered sets. 2446 for (const auto& table_pair : remembered_sets_) { 2447 accounting::RememberedSet* remembered_set = table_pair.second; 2448 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2449 } 2450 DumpSpaces(LOG(ERROR)); 2451 } 2452 return visitor.GetFailureCount(); 2453} 2454 2455class VerifyReferenceCardVisitor { 2456 public: 2457 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2458 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2459 Locks::heap_bitmap_lock_) 2460 : heap_(heap), failed_(failed) { 2461 } 2462 2463 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2464 // annotalysis on visitors. 2465 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2466 NO_THREAD_SAFETY_ANALYSIS { 2467 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2468 // Filter out class references since changing an object's class does not mark the card as dirty. 2469 // Also handles large objects, since the only reference they hold is a class reference. 2470 if (ref != nullptr && !ref->IsClass()) { 2471 accounting::CardTable* card_table = heap_->GetCardTable(); 2472 // If the object is not dirty and it is referencing something in the live stack other than 2473 // class, then it must be on a dirty card. 2474 if (!card_table->AddrIsInCardTable(obj)) { 2475 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2476 *failed_ = true; 2477 } else if (!card_table->IsDirty(obj)) { 2478 // TODO: Check mod-union tables. 2479 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2480 // kCardDirty - 1 if it didnt get touched since we aged it. 2481 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2482 if (live_stack->ContainsSorted(ref)) { 2483 if (live_stack->ContainsSorted(obj)) { 2484 LOG(ERROR) << "Object " << obj << " found in live stack"; 2485 } 2486 if (heap_->GetLiveBitmap()->Test(obj)) { 2487 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2488 } 2489 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2490 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2491 2492 // Print which field of the object is dead. 2493 if (!obj->IsObjectArray()) { 2494 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2495 CHECK(klass != NULL); 2496 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2497 : klass->GetIFields(); 2498 CHECK(fields != NULL); 2499 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2500 mirror::ArtField* cur = fields->Get(i); 2501 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2502 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2503 << PrettyField(cur); 2504 break; 2505 } 2506 } 2507 } else { 2508 mirror::ObjectArray<mirror::Object>* object_array = 2509 obj->AsObjectArray<mirror::Object>(); 2510 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2511 if (object_array->Get(i) == ref) { 2512 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2513 } 2514 } 2515 } 2516 2517 *failed_ = true; 2518 } 2519 } 2520 } 2521 } 2522 2523 private: 2524 Heap* const heap_; 2525 bool* const failed_; 2526}; 2527 2528class VerifyLiveStackReferences { 2529 public: 2530 explicit VerifyLiveStackReferences(Heap* heap) 2531 : heap_(heap), 2532 failed_(false) {} 2533 2534 void operator()(mirror::Object* obj) const 2535 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2536 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2537 obj->VisitReferences<true>(visitor, VoidFunctor()); 2538 } 2539 2540 bool Failed() const { 2541 return failed_; 2542 } 2543 2544 private: 2545 Heap* const heap_; 2546 bool failed_; 2547}; 2548 2549bool Heap::VerifyMissingCardMarks() { 2550 Thread* self = Thread::Current(); 2551 Locks::mutator_lock_->AssertExclusiveHeld(self); 2552 // We need to sort the live stack since we binary search it. 2553 live_stack_->Sort(); 2554 // Since we sorted the allocation stack content, need to revoke all 2555 // thread-local allocation stacks. 2556 RevokeAllThreadLocalAllocationStacks(self); 2557 VerifyLiveStackReferences visitor(this); 2558 GetLiveBitmap()->Visit(visitor); 2559 // We can verify objects in the live stack since none of these should reference dead objects. 2560 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2561 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2562 visitor(*it); 2563 } 2564 } 2565 return !visitor.Failed(); 2566} 2567 2568void Heap::SwapStacks(Thread* self) { 2569 if (kUseThreadLocalAllocationStack) { 2570 live_stack_->AssertAllZero(); 2571 } 2572 allocation_stack_.swap(live_stack_); 2573} 2574 2575void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2576 // This must be called only during the pause. 2577 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2578 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2579 MutexLock mu2(self, *Locks::thread_list_lock_); 2580 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2581 for (Thread* t : thread_list) { 2582 t->RevokeThreadLocalAllocationStack(); 2583 } 2584} 2585 2586void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2587 if (kIsDebugBuild) { 2588 if (bump_pointer_space_ != nullptr) { 2589 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2590 } 2591 } 2592} 2593 2594accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2595 auto it = mod_union_tables_.find(space); 2596 if (it == mod_union_tables_.end()) { 2597 return nullptr; 2598 } 2599 return it->second; 2600} 2601 2602accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2603 auto it = remembered_sets_.find(space); 2604 if (it == remembered_sets_.end()) { 2605 return nullptr; 2606 } 2607 return it->second; 2608} 2609 2610void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2611 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2612 // Clear cards and keep track of cards cleared in the mod-union table. 2613 for (const auto& space : continuous_spaces_) { 2614 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2615 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2616 if (table != nullptr) { 2617 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2618 "ImageModUnionClearCards"; 2619 TimingLogger::ScopedTiming t(name, timings); 2620 table->ClearCards(); 2621 } else if (use_rem_sets && rem_set != nullptr) { 2622 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2623 << static_cast<int>(collector_type_); 2624 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2625 rem_set->ClearCards(); 2626 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2627 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2628 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2629 // were dirty before the GC started. 2630 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2631 // -> clean(cleaning thread). 2632 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2633 // roots and then we scan / update mod union tables after. We will always scan either card. 2634 // If we end up with the non aged card, we scan it it in the pause. 2635 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2636 VoidFunctor()); 2637 } 2638 } 2639} 2640 2641static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2642} 2643 2644void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2645 Thread* const self = Thread::Current(); 2646 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2647 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2648 if (verify_pre_gc_heap_) { 2649 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2650 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2651 size_t failures = VerifyHeapReferences(); 2652 if (failures > 0) { 2653 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2654 << " failures"; 2655 } 2656 } 2657 // Check that all objects which reference things in the live stack are on dirty cards. 2658 if (verify_missing_card_marks_) { 2659 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2660 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2661 SwapStacks(self); 2662 // Sort the live stack so that we can quickly binary search it later. 2663 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2664 << " missing card mark verification failed\n" << DumpSpaces(); 2665 SwapStacks(self); 2666 } 2667 if (verify_mod_union_table_) { 2668 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2669 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2670 for (const auto& table_pair : mod_union_tables_) { 2671 accounting::ModUnionTable* mod_union_table = table_pair.second; 2672 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2673 mod_union_table->Verify(); 2674 } 2675 } 2676} 2677 2678void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2679 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2680 collector::GarbageCollector::ScopedPause pause(gc); 2681 PreGcVerificationPaused(gc); 2682 } 2683} 2684 2685void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2686 // TODO: Add a new runtime option for this? 2687 if (verify_pre_gc_rosalloc_) { 2688 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2689 } 2690} 2691 2692void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2693 Thread* const self = Thread::Current(); 2694 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2695 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2696 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2697 // reachable objects. 2698 if (verify_pre_sweeping_heap_) { 2699 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2700 CHECK_NE(self->GetState(), kRunnable); 2701 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2702 // Swapping bound bitmaps does nothing. 2703 gc->SwapBitmaps(); 2704 // Pass in false since concurrent reference processing can mean that the reference referents 2705 // may point to dead objects at the point which PreSweepingGcVerification is called. 2706 size_t failures = VerifyHeapReferences(false); 2707 if (failures > 0) { 2708 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2709 << " failures"; 2710 } 2711 gc->SwapBitmaps(); 2712 } 2713 if (verify_pre_sweeping_rosalloc_) { 2714 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2715 } 2716} 2717 2718void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2719 // Only pause if we have to do some verification. 2720 Thread* const self = Thread::Current(); 2721 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2722 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2723 if (verify_system_weaks_) { 2724 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2725 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2726 mark_sweep->VerifySystemWeaks(); 2727 } 2728 if (verify_post_gc_rosalloc_) { 2729 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2730 } 2731 if (verify_post_gc_heap_) { 2732 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2733 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2734 size_t failures = VerifyHeapReferences(); 2735 if (failures > 0) { 2736 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2737 << " failures"; 2738 } 2739 } 2740} 2741 2742void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2743 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2744 collector::GarbageCollector::ScopedPause pause(gc); 2745 PostGcVerificationPaused(gc); 2746 } 2747} 2748 2749void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2750 TimingLogger::ScopedTiming t(name, timings); 2751 for (const auto& space : continuous_spaces_) { 2752 if (space->IsRosAllocSpace()) { 2753 VLOG(heap) << name << " : " << space->GetName(); 2754 space->AsRosAllocSpace()->Verify(); 2755 } 2756 } 2757} 2758 2759collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2760 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2761 MutexLock mu(self, *gc_complete_lock_); 2762 return WaitForGcToCompleteLocked(cause, self); 2763} 2764 2765collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2766 collector::GcType last_gc_type = collector::kGcTypeNone; 2767 uint64_t wait_start = NanoTime(); 2768 while (collector_type_running_ != kCollectorTypeNone) { 2769 ATRACE_BEGIN("GC: Wait For Completion"); 2770 // We must wait, change thread state then sleep on gc_complete_cond_; 2771 gc_complete_cond_->Wait(self); 2772 last_gc_type = last_gc_type_; 2773 ATRACE_END(); 2774 } 2775 uint64_t wait_time = NanoTime() - wait_start; 2776 total_wait_time_ += wait_time; 2777 if (wait_time > long_pause_log_threshold_) { 2778 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2779 << " for cause " << cause; 2780 } 2781 return last_gc_type; 2782} 2783 2784void Heap::DumpForSigQuit(std::ostream& os) { 2785 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2786 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2787 DumpGcPerformanceInfo(os); 2788} 2789 2790size_t Heap::GetPercentFree() { 2791 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2792} 2793 2794void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2795 if (max_allowed_footprint > GetMaxMemory()) { 2796 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2797 << PrettySize(GetMaxMemory()); 2798 max_allowed_footprint = GetMaxMemory(); 2799 } 2800 max_allowed_footprint_ = max_allowed_footprint; 2801} 2802 2803bool Heap::IsMovableObject(const mirror::Object* obj) const { 2804 if (kMovingCollector) { 2805 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2806 if (space != nullptr) { 2807 // TODO: Check large object? 2808 return space->CanMoveObjects(); 2809 } 2810 } 2811 return false; 2812} 2813 2814void Heap::UpdateMaxNativeFootprint() { 2815 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2816 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2817 size_t target_size = native_size / GetTargetHeapUtilization(); 2818 if (target_size > native_size + max_free_) { 2819 target_size = native_size + max_free_; 2820 } else if (target_size < native_size + min_free_) { 2821 target_size = native_size + min_free_; 2822 } 2823 native_footprint_gc_watermark_ = std::min(growth_limit_, target_size); 2824} 2825 2826collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2827 for (const auto& collector : garbage_collectors_) { 2828 if (collector->GetCollectorType() == collector_type_ && 2829 collector->GetGcType() == gc_type) { 2830 return collector; 2831 } 2832 } 2833 return nullptr; 2834} 2835 2836double Heap::HeapGrowthMultiplier() const { 2837 // If we don't care about pause times we are background, so return 1.0. 2838 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2839 return 1.0; 2840 } 2841 return foreground_heap_growth_multiplier_; 2842} 2843 2844void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2845 // We know what our utilization is at this moment. 2846 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2847 const uint64_t bytes_allocated = GetBytesAllocated(); 2848 last_gc_size_ = bytes_allocated; 2849 last_gc_time_ns_ = NanoTime(); 2850 uint64_t target_size; 2851 collector::GcType gc_type = collector_ran->GetGcType(); 2852 if (gc_type != collector::kGcTypeSticky) { 2853 // Grow the heap for non sticky GC. 2854 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2855 // foreground. 2856 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2857 CHECK_GE(delta, 0); 2858 target_size = bytes_allocated + delta * multiplier; 2859 target_size = std::min(target_size, 2860 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2861 target_size = std::max(target_size, 2862 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2863 native_need_to_run_finalization_ = true; 2864 next_gc_type_ = collector::kGcTypeSticky; 2865 } else { 2866 collector::GcType non_sticky_gc_type = 2867 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2868 // Find what the next non sticky collector will be. 2869 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2870 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2871 // do another sticky collection next. 2872 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2873 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2874 // if the sticky GC throughput always remained >= the full/partial throughput. 2875 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2876 non_sticky_collector->GetEstimatedMeanThroughput() && 2877 non_sticky_collector->NumberOfIterations() > 0 && 2878 bytes_allocated <= max_allowed_footprint_) { 2879 next_gc_type_ = collector::kGcTypeSticky; 2880 } else { 2881 next_gc_type_ = non_sticky_gc_type; 2882 } 2883 // If we have freed enough memory, shrink the heap back down. 2884 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2885 target_size = bytes_allocated + max_free_; 2886 } else { 2887 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2888 } 2889 } 2890 if (!ignore_max_footprint_) { 2891 SetIdealFootprint(target_size); 2892 if (IsGcConcurrent()) { 2893 // Calculate when to perform the next ConcurrentGC. 2894 // Calculate the estimated GC duration. 2895 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2896 // Estimate how many remaining bytes we will have when we need to start the next GC. 2897 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2898 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2899 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2900 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2901 // A never going to happen situation that from the estimated allocation rate we will exceed 2902 // the applications entire footprint with the given estimated allocation rate. Schedule 2903 // another GC nearly straight away. 2904 remaining_bytes = kMinConcurrentRemainingBytes; 2905 } 2906 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2907 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2908 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2909 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2910 // right away. 2911 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2912 static_cast<size_t>(bytes_allocated)); 2913 } 2914 } 2915} 2916 2917void Heap::ClearGrowthLimit() { 2918 growth_limit_ = capacity_; 2919 non_moving_space_->ClearGrowthLimit(); 2920} 2921 2922void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2923 ScopedObjectAccess soa(self); 2924 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2925 jvalue args[1]; 2926 args[0].l = arg.get(); 2927 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2928 // Restore object in case it gets moved. 2929 *object = soa.Decode<mirror::Object*>(arg.get()); 2930} 2931 2932void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2933 StackHandleScope<1> hs(self); 2934 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2935 RequestConcurrentGC(self); 2936} 2937 2938void Heap::RequestConcurrentGC(Thread* self) { 2939 // Make sure that we can do a concurrent GC. 2940 Runtime* runtime = Runtime::Current(); 2941 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2942 self->IsHandlingStackOverflow()) { 2943 return; 2944 } 2945 // We already have a request pending, no reason to start more until we update 2946 // concurrent_start_bytes_. 2947 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2948 JNIEnv* env = self->GetJniEnv(); 2949 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2950 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2951 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2952 WellKnownClasses::java_lang_Daemons_requestGC); 2953 CHECK(!env->ExceptionCheck()); 2954} 2955 2956void Heap::ConcurrentGC(Thread* self) { 2957 if (Runtime::Current()->IsShuttingDown(self)) { 2958 return; 2959 } 2960 // Wait for any GCs currently running to finish. 2961 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2962 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2963 // instead. E.g. can't do partial, so do full instead. 2964 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2965 collector::kGcTypeNone) { 2966 for (collector::GcType gc_type : gc_plan_) { 2967 // Attempt to run the collector, if we succeed, we are done. 2968 if (gc_type > next_gc_type_ && 2969 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2970 break; 2971 } 2972 } 2973 } 2974 } 2975} 2976 2977void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2978 Thread* self = Thread::Current(); 2979 { 2980 MutexLock mu(self, *heap_trim_request_lock_); 2981 if (desired_collector_type_ == desired_collector_type) { 2982 return; 2983 } 2984 desired_collector_type_ = desired_collector_type; 2985 } 2986 SignalHeapTrimDaemon(self); 2987} 2988 2989void Heap::RequestHeapTrim() { 2990 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2991 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2992 // a space it will hold its lock and can become a cause of jank. 2993 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2994 // forking. 2995 2996 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2997 // because that only marks object heads, so a large array looks like lots of empty space. We 2998 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2999 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3000 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3001 // not how much use we're making of those pages. 3002 3003 Thread* self = Thread::Current(); 3004 Runtime* runtime = Runtime::Current(); 3005 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 3006 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3007 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3008 // as we don't hold the lock while requesting the trim). 3009 return; 3010 } 3011 { 3012 MutexLock mu(self, *heap_trim_request_lock_); 3013 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3014 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3015 // just yet. 3016 return; 3017 } 3018 heap_trim_request_pending_ = true; 3019 } 3020 // Notify the daemon thread which will actually do the heap trim. 3021 SignalHeapTrimDaemon(self); 3022} 3023 3024void Heap::SignalHeapTrimDaemon(Thread* self) { 3025 JNIEnv* env = self->GetJniEnv(); 3026 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3027 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3028 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3029 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3030 CHECK(!env->ExceptionCheck()); 3031} 3032 3033void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3034 if (rosalloc_space_ != nullptr) { 3035 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3036 } 3037 if (bump_pointer_space_ != nullptr) { 3038 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3039 } 3040} 3041 3042void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3043 if (rosalloc_space_ != nullptr) { 3044 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3045 } 3046} 3047 3048void Heap::RevokeAllThreadLocalBuffers() { 3049 if (rosalloc_space_ != nullptr) { 3050 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3051 } 3052 if (bump_pointer_space_ != nullptr) { 3053 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3054 } 3055} 3056 3057bool Heap::IsGCRequestPending() const { 3058 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3059} 3060 3061void Heap::RunFinalization(JNIEnv* env) { 3062 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3063 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3064 CHECK(WellKnownClasses::java_lang_System != nullptr); 3065 WellKnownClasses::java_lang_System_runFinalization = 3066 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3067 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3068 } 3069 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3070 WellKnownClasses::java_lang_System_runFinalization); 3071 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3072 WellKnownClasses::java_lang_System_runFinalization); 3073} 3074 3075void Heap::RegisterNativeAllocation(JNIEnv* env, size_t bytes) { 3076 Thread* self = ThreadForEnv(env); 3077 if (native_need_to_run_finalization_) { 3078 RunFinalization(env); 3079 UpdateMaxNativeFootprint(); 3080 native_need_to_run_finalization_ = false; 3081 } 3082 // Total number of native bytes allocated. 3083 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3084 new_native_bytes_allocated += bytes; 3085 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3086 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 3087 collector::kGcTypeFull; 3088 3089 // The second watermark is higher than the gc watermark. If you hit this it means you are 3090 // allocating native objects faster than the GC can keep up with. 3091 if (new_native_bytes_allocated > growth_limit_) { 3092 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3093 // Just finished a GC, attempt to run finalizers. 3094 RunFinalization(env); 3095 CHECK(!env->ExceptionCheck()); 3096 } 3097 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3098 if (new_native_bytes_allocated > growth_limit_) { 3099 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3100 RunFinalization(env); 3101 native_need_to_run_finalization_ = false; 3102 CHECK(!env->ExceptionCheck()); 3103 } 3104 // We have just run finalizers, update the native watermark since it is very likely that 3105 // finalizers released native managed allocations. 3106 UpdateMaxNativeFootprint(); 3107 } else if (!IsGCRequestPending()) { 3108 if (IsGcConcurrent()) { 3109 RequestConcurrentGC(self); 3110 } else { 3111 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3112 } 3113 } 3114 } 3115} 3116 3117void Heap::RegisterNativeFree(JNIEnv* env, size_t bytes) { 3118 size_t expected_size; 3119 do { 3120 expected_size = native_bytes_allocated_.LoadRelaxed(); 3121 if (UNLIKELY(bytes > expected_size)) { 3122 ScopedObjectAccess soa(env); 3123 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3124 StringPrintf("Attempted to free %zd native bytes with only %zd native bytes " 3125 "registered as allocated", bytes, expected_size).c_str()); 3126 break; 3127 } 3128 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, 3129 expected_size - bytes)); 3130} 3131 3132size_t Heap::GetTotalMemory() const { 3133 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3134} 3135 3136void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3137 DCHECK(mod_union_table != nullptr); 3138 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3139} 3140 3141void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3142 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3143 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3144 CHECK_GE(byte_count, sizeof(mirror::Object)); 3145} 3146 3147void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3148 CHECK(remembered_set != nullptr); 3149 space::Space* space = remembered_set->GetSpace(); 3150 CHECK(space != nullptr); 3151 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3152 remembered_sets_.Put(space, remembered_set); 3153 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3154} 3155 3156void Heap::RemoveRememberedSet(space::Space* space) { 3157 CHECK(space != nullptr); 3158 auto it = remembered_sets_.find(space); 3159 CHECK(it != remembered_sets_.end()); 3160 delete it->second; 3161 remembered_sets_.erase(it); 3162 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3163} 3164 3165void Heap::ClearMarkedObjects() { 3166 // Clear all of the spaces' mark bitmaps. 3167 for (const auto& space : GetContinuousSpaces()) { 3168 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3169 if (space->GetLiveBitmap() != mark_bitmap) { 3170 mark_bitmap->Clear(); 3171 } 3172 } 3173 // Clear the marked objects in the discontinous space object sets. 3174 for (const auto& space : GetDiscontinuousSpaces()) { 3175 space->GetMarkBitmap()->Clear(); 3176 } 3177} 3178 3179} // namespace gc 3180} // namespace art 3181