heap.cc revision b27285583ca40253b76010948420a91b45f79257
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 heap_transition_or_trim_target_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 zygote_space_(nullptr), 133 large_object_threshold_(kDefaultLargeObjectThreshold), // 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 // Background compaction is currently not supported for command line runs. 194 if (background_collector_type_ != foreground_collector_type_) { 195 VLOG(heap) << "Disabling background compaction for non zygote"; 196 background_collector_type_ = foreground_collector_type_; 197 } 198 } 199 ChangeCollector(desired_collector_type_); 200 live_bitmap_.reset(new accounting::HeapBitmap(this)); 201 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 202 // Requested begin for the alloc space, to follow the mapped image and oat files 203 byte* requested_alloc_space_begin = nullptr; 204 if (!image_file_name.empty()) { 205 std::string error_msg; 206 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 207 image_instruction_set, 208 &error_msg); 209 if (image_space != nullptr) { 210 AddSpace(image_space); 211 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 212 // isn't going to get in the middle 213 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 214 CHECK_GT(oat_file_end_addr, image_space->End()); 215 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 216 } else { 217 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 218 << "Attempting to fall back to imageless running. Error was: " << error_msg; 219 } 220 } 221 /* 222 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 223 +- nonmoving space (non_moving_space_capacity)+- 224 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 225 +-????????????????????????????????????????????+- 226 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 227 +-main alloc space / bump space 1 (capacity_) +- 228 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 229 +-????????????????????????????????????????????+- 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 231 +-main alloc space2 / bump space 2 (capacity_)+- 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 233 */ 234 bool support_homogeneous_space_compaction = 235 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 236 use_homogeneous_space_compaction_for_oom; 237 // We may use the same space the main space for the non moving space if we don't need to compact 238 // from the main space. 239 // This is not the case if we support homogeneous compaction or have a moving background 240 // collector type. 241 bool separate_non_moving_space = is_zygote || 242 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 243 IsMovingGc(background_collector_type_); 244 if (foreground_collector_type == kCollectorTypeGSS) { 245 separate_non_moving_space = false; 246 } 247 std::unique_ptr<MemMap> main_mem_map_1; 248 std::unique_ptr<MemMap> main_mem_map_2; 249 byte* request_begin = requested_alloc_space_begin; 250 if (request_begin != nullptr && separate_non_moving_space) { 251 request_begin += non_moving_space_capacity; 252 } 253 std::string error_str; 254 std::unique_ptr<MemMap> non_moving_space_mem_map; 255 if (separate_non_moving_space) { 256 // Reserve the non moving mem map before the other two since it needs to be at a specific 257 // address. 258 non_moving_space_mem_map.reset( 259 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 260 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 261 CHECK(non_moving_space_mem_map != nullptr) << error_str; 262 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 263 request_begin = reinterpret_cast<byte*>(0x1000000); 264 } 265 // Attempt to create 2 mem maps at or after the requested begin. 266 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 267 PROT_READ | PROT_WRITE, &error_str)); 268 CHECK(main_mem_map_1.get() != nullptr) << error_str; 269 if (support_homogeneous_space_compaction || 270 background_collector_type_ == kCollectorTypeSS || 271 foreground_collector_type_ == kCollectorTypeSS) { 272 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 273 capacity_, PROT_READ | PROT_WRITE, 274 &error_str)); 275 CHECK(main_mem_map_2.get() != nullptr) << error_str; 276 } 277 // Create the non moving space first so that bitmaps don't take up the address range. 278 if (separate_non_moving_space) { 279 // Non moving space is always dlmalloc since we currently don't have support for multiple 280 // active rosalloc spaces. 281 const size_t size = non_moving_space_mem_map->Size(); 282 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 283 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 284 initial_size, size, size, false); 285 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 286 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 287 << requested_alloc_space_begin; 288 AddSpace(non_moving_space_); 289 } 290 // Create other spaces based on whether or not we have a moving GC. 291 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 292 // Create bump pointer spaces. 293 // We only to create the bump pointer if the foreground collector is a compacting GC. 294 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 295 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 296 main_mem_map_1.release()); 297 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 298 AddSpace(bump_pointer_space_); 299 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 300 main_mem_map_2.release()); 301 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 302 AddSpace(temp_space_); 303 CHECK(separate_non_moving_space); 304 } else { 305 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 306 CHECK(main_space_ != nullptr); 307 AddSpace(main_space_); 308 if (!separate_non_moving_space) { 309 non_moving_space_ = main_space_; 310 CHECK(!non_moving_space_->CanMoveObjects()); 311 } 312 if (foreground_collector_type_ == kCollectorTypeGSS) { 313 CHECK_EQ(foreground_collector_type_, background_collector_type_); 314 // Create bump pointer spaces instead of a backup space. 315 main_mem_map_2.release(); 316 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 317 kGSSBumpPointerSpaceCapacity, nullptr); 318 CHECK(bump_pointer_space_ != nullptr); 319 AddSpace(bump_pointer_space_); 320 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 321 kGSSBumpPointerSpaceCapacity, nullptr); 322 CHECK(temp_space_ != nullptr); 323 AddSpace(temp_space_); 324 } else if (main_mem_map_2.get() != nullptr) { 325 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 326 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 327 growth_limit_, capacity_, name, true)); 328 CHECK(main_space_backup_.get() != nullptr); 329 // Add the space so its accounted for in the heap_begin and heap_end. 330 AddSpace(main_space_backup_.get()); 331 } 332 } 333 CHECK(non_moving_space_ != nullptr); 334 CHECK(!non_moving_space_->CanMoveObjects()); 335 // Allocate the large object space. 336 if (kUseFreeListSpaceForLOS) { 337 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 338 } else { 339 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 340 } 341 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 342 AddSpace(large_object_space_); 343 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 344 CHECK(!continuous_spaces_.empty()); 345 // Relies on the spaces being sorted. 346 byte* heap_begin = continuous_spaces_.front()->Begin(); 347 byte* heap_end = continuous_spaces_.back()->Limit(); 348 size_t heap_capacity = heap_end - heap_begin; 349 // Remove the main backup space since it slows down the GC to have unused extra spaces. 350 if (main_space_backup_.get() != nullptr) { 351 RemoveSpace(main_space_backup_.get()); 352 } 353 // Allocate the card table. 354 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 355 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 356 // Card cache for now since it makes it easier for us to update the references to the copying 357 // spaces. 358 accounting::ModUnionTable* mod_union_table = 359 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 360 GetImageSpace()); 361 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 362 AddModUnionTable(mod_union_table); 363 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 364 accounting::RememberedSet* non_moving_space_rem_set = 365 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 366 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 367 AddRememberedSet(non_moving_space_rem_set); 368 } 369 // TODO: Count objects in the image space here? 370 num_bytes_allocated_.StoreRelaxed(0); 371 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 372 kDefaultMarkStackSize)); 373 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 374 allocation_stack_.reset(accounting::ObjectStack::Create( 375 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 376 live_stack_.reset(accounting::ObjectStack::Create( 377 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 378 // It's still too early to take a lock because there are no threads yet, but we can create locks 379 // now. We don't create it earlier to make it clear that you can't use locks during heap 380 // initialization. 381 gc_complete_lock_ = new Mutex("GC complete lock"); 382 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 383 *gc_complete_lock_)); 384 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 385 last_gc_size_ = GetBytesAllocated(); 386 if (ignore_max_footprint_) { 387 SetIdealFootprint(std::numeric_limits<size_t>::max()); 388 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 389 } 390 CHECK_NE(max_allowed_footprint_, 0U); 391 // Create our garbage collectors. 392 for (size_t i = 0; i < 2; ++i) { 393 const bool concurrent = i != 0; 394 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 395 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 396 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 397 } 398 if (kMovingCollector) { 399 // TODO: Clean this up. 400 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 401 semi_space_collector_ = new collector::SemiSpace(this, generational, 402 generational ? "generational" : ""); 403 garbage_collectors_.push_back(semi_space_collector_); 404 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 405 garbage_collectors_.push_back(concurrent_copying_collector_); 406 mark_compact_collector_ = new collector::MarkCompact(this); 407 garbage_collectors_.push_back(mark_compact_collector_); 408 } 409 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr && 410 (is_zygote || separate_non_moving_space || foreground_collector_type_ == kCollectorTypeGSS)) { 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). This is only 413 // required when we're the zygote or using GSS. 414 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 415 non_moving_space_->GetMemMap()); 416 if (!no_gap) { 417 MemMap::DumpMaps(LOG(ERROR)); 418 LOG(FATAL) << "There's a gap between the image space and the main space"; 419 } 420 } 421 if (running_on_valgrind_) { 422 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 423 } 424 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 425 LOG(INFO) << "Heap() exiting"; 426 } 427} 428 429MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 430 int prot_flags, std::string* out_error_str) { 431 while (true) { 432 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 433 PROT_READ | PROT_WRITE, true, out_error_str); 434 if (map != nullptr || request_begin == nullptr) { 435 return map; 436 } 437 // Retry a second time with no specified request begin. 438 request_begin = nullptr; 439 } 440 return nullptr; 441} 442 443space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 444 size_t growth_limit, size_t capacity, 445 const char* name, bool can_move_objects) { 446 space::MallocSpace* malloc_space = nullptr; 447 if (kUseRosAlloc) { 448 // Create rosalloc space. 449 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 450 initial_size, growth_limit, capacity, 451 low_memory_mode_, can_move_objects); 452 } else { 453 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 454 initial_size, growth_limit, capacity, 455 can_move_objects); 456 } 457 if (collector::SemiSpace::kUseRememberedSet) { 458 accounting::RememberedSet* rem_set = 459 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 460 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 461 AddRememberedSet(rem_set); 462 } 463 CHECK(malloc_space != nullptr) << "Failed to create " << name; 464 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 465 return malloc_space; 466} 467 468void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 469 size_t capacity) { 470 // Is background compaction is enabled? 471 bool can_move_objects = IsMovingGc(background_collector_type_) != 472 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 473 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 474 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 475 // from the main space to the zygote space. If background compaction is enabled, always pass in 476 // that we can move objets. 477 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 478 // After the zygote we want this to be false if we don't have background compaction enabled so 479 // that getting primitive array elements is faster. 480 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 481 can_move_objects = !HasZygoteSpace() && foreground_collector_type_ != kCollectorTypeGSS; 482 } 483 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 484 RemoveRememberedSet(main_space_); 485 } 486 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 487 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 488 can_move_objects); 489 SetSpaceAsDefault(main_space_); 490 VLOG(heap) << "Created main space " << main_space_; 491} 492 493void Heap::ChangeAllocator(AllocatorType allocator) { 494 if (current_allocator_ != allocator) { 495 // These two allocators are only used internally and don't have any entrypoints. 496 CHECK_NE(allocator, kAllocatorTypeLOS); 497 CHECK_NE(allocator, kAllocatorTypeNonMoving); 498 current_allocator_ = allocator; 499 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 500 SetQuickAllocEntryPointsAllocator(current_allocator_); 501 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 502 } 503} 504 505void Heap::DisableMovingGc() { 506 if (IsMovingGc(foreground_collector_type_)) { 507 foreground_collector_type_ = kCollectorTypeCMS; 508 } 509 if (IsMovingGc(background_collector_type_)) { 510 background_collector_type_ = foreground_collector_type_; 511 } 512 TransitionCollector(foreground_collector_type_); 513 ThreadList* tl = Runtime::Current()->GetThreadList(); 514 Thread* self = Thread::Current(); 515 ScopedThreadStateChange tsc(self, kSuspended); 516 tl->SuspendAll(); 517 // Something may have caused the transition to fail. 518 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 519 CHECK(main_space_ != nullptr); 520 // The allocation stack may have non movable objects in it. We need to flush it since the GC 521 // can't only handle marking allocation stack objects of one non moving space and one main 522 // space. 523 { 524 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 525 FlushAllocStack(); 526 } 527 main_space_->DisableMovingObjects(); 528 non_moving_space_ = main_space_; 529 CHECK(!non_moving_space_->CanMoveObjects()); 530 } 531 tl->ResumeAll(); 532} 533 534std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 535 if (!IsValidContinuousSpaceObjectAddress(klass)) { 536 return StringPrintf("<non heap address klass %p>", klass); 537 } 538 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 539 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 540 std::string result("["); 541 result += SafeGetClassDescriptor(component_type); 542 return result; 543 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 544 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 545 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 546 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 547 } else { 548 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 549 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 550 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 551 } 552 const DexFile* dex_file = dex_cache->GetDexFile(); 553 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 554 if (class_def_idx == DexFile::kDexNoIndex16) { 555 return "<class def not found>"; 556 } 557 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 558 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 559 return dex_file->GetTypeDescriptor(type_id); 560 } 561} 562 563std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 564 if (obj == nullptr) { 565 return "null"; 566 } 567 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 568 if (klass == nullptr) { 569 return "(class=null)"; 570 } 571 std::string result(SafeGetClassDescriptor(klass)); 572 if (obj->IsClass()) { 573 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 574 } 575 return result; 576} 577 578void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 579 if (obj == nullptr) { 580 stream << "(obj=null)"; 581 return; 582 } 583 if (IsAligned<kObjectAlignment>(obj)) { 584 space::Space* space = nullptr; 585 // Don't use find space since it only finds spaces which actually contain objects instead of 586 // spaces which may contain objects (e.g. cleared bump pointer spaces). 587 for (const auto& cur_space : continuous_spaces_) { 588 if (cur_space->HasAddress(obj)) { 589 space = cur_space; 590 break; 591 } 592 } 593 // Unprotect all the spaces. 594 for (const auto& space : continuous_spaces_) { 595 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 596 } 597 stream << "Object " << obj; 598 if (space != nullptr) { 599 stream << " in space " << *space; 600 } 601 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 602 stream << "\nclass=" << klass; 603 if (klass != nullptr) { 604 stream << " type= " << SafePrettyTypeOf(obj); 605 } 606 // Re-protect the address we faulted on. 607 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 608 } 609} 610 611bool Heap::IsCompilingBoot() const { 612 if (!Runtime::Current()->IsCompiler()) { 613 return false; 614 } 615 for (const auto& space : continuous_spaces_) { 616 if (space->IsImageSpace() || space->IsZygoteSpace()) { 617 return false; 618 } 619 } 620 return true; 621} 622 623bool Heap::HasImageSpace() const { 624 for (const auto& space : continuous_spaces_) { 625 if (space->IsImageSpace()) { 626 return true; 627 } 628 } 629 return false; 630} 631 632void Heap::IncrementDisableMovingGC(Thread* self) { 633 // Need to do this holding the lock to prevent races where the GC is about to run / running when 634 // we attempt to disable it. 635 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 636 MutexLock mu(self, *gc_complete_lock_); 637 ++disable_moving_gc_count_; 638 if (IsMovingGc(collector_type_running_)) { 639 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 640 } 641} 642 643void Heap::DecrementDisableMovingGC(Thread* self) { 644 MutexLock mu(self, *gc_complete_lock_); 645 CHECK_GE(disable_moving_gc_count_, 0U); 646 --disable_moving_gc_count_; 647} 648 649void Heap::UpdateProcessState(ProcessState process_state) { 650 if (process_state_ != process_state) { 651 process_state_ = process_state; 652 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 653 // Start at index 1 to avoid "is always false" warning. 654 // Have iteration 1 always transition the collector. 655 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 656 ? foreground_collector_type_ : background_collector_type_); 657 usleep(kCollectorTransitionStressWait); 658 } 659 if (process_state_ == kProcessStateJankPerceptible) { 660 // Transition back to foreground right away to prevent jank. 661 RequestCollectorTransition(foreground_collector_type_, 0); 662 } else { 663 // Don't delay for debug builds since we may want to stress test the GC. 664 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 665 // special handling which does a homogenous space compaction once but then doesn't transition 666 // the collector. 667 RequestCollectorTransition(background_collector_type_, 668 kIsDebugBuild ? 0 : kCollectorTransitionWait); 669 } 670 } 671} 672 673void Heap::CreateThreadPool() { 674 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 675 if (num_threads != 0) { 676 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 677 } 678} 679 680void Heap::VisitObjects(ObjectCallback callback, void* arg) { 681 Thread* self = Thread::Current(); 682 // GCs can move objects, so don't allow this. 683 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 684 if (bump_pointer_space_ != nullptr) { 685 // Visit objects in bump pointer space. 686 bump_pointer_space_->Walk(callback, arg); 687 } 688 // TODO: Switch to standard begin and end to use ranged a based loop. 689 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 690 it < end; ++it) { 691 mirror::Object* obj = *it; 692 if (obj != nullptr && obj->GetClass() != nullptr) { 693 // Avoid the race condition caused by the object not yet being written into the allocation 694 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 695 // there can be nulls on the allocation stack. 696 callback(obj, arg); 697 } 698 } 699 GetLiveBitmap()->Walk(callback, arg); 700 self->EndAssertNoThreadSuspension(old_cause); 701} 702 703void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 704 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 705 space::ContinuousSpace* space2 = non_moving_space_; 706 // TODO: Generalize this to n bitmaps? 707 CHECK(space1 != nullptr); 708 CHECK(space2 != nullptr); 709 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 710 large_object_space_->GetLiveBitmap(), stack); 711} 712 713void Heap::DeleteThreadPool() { 714 thread_pool_.reset(nullptr); 715} 716 717void Heap::AddSpace(space::Space* space) { 718 CHECK(space != nullptr); 719 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 720 if (space->IsContinuousSpace()) { 721 DCHECK(!space->IsDiscontinuousSpace()); 722 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 723 // Continuous spaces don't necessarily have bitmaps. 724 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 725 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 726 if (live_bitmap != nullptr) { 727 CHECK(mark_bitmap != nullptr); 728 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 729 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 730 } 731 continuous_spaces_.push_back(continuous_space); 732 // Ensure that spaces remain sorted in increasing order of start address. 733 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 734 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 735 return a->Begin() < b->Begin(); 736 }); 737 } else { 738 CHECK(space->IsDiscontinuousSpace()); 739 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 740 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 741 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 742 discontinuous_spaces_.push_back(discontinuous_space); 743 } 744 if (space->IsAllocSpace()) { 745 alloc_spaces_.push_back(space->AsAllocSpace()); 746 } 747} 748 749void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 750 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 751 if (continuous_space->IsDlMallocSpace()) { 752 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 753 } else if (continuous_space->IsRosAllocSpace()) { 754 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 755 } 756} 757 758void Heap::RemoveSpace(space::Space* space) { 759 DCHECK(space != nullptr); 760 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 761 if (space->IsContinuousSpace()) { 762 DCHECK(!space->IsDiscontinuousSpace()); 763 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 764 // Continuous spaces don't necessarily have bitmaps. 765 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 766 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 767 if (live_bitmap != nullptr) { 768 DCHECK(mark_bitmap != nullptr); 769 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 770 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 771 } 772 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 773 DCHECK(it != continuous_spaces_.end()); 774 continuous_spaces_.erase(it); 775 } else { 776 DCHECK(space->IsDiscontinuousSpace()); 777 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 778 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 779 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 780 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 781 discontinuous_space); 782 DCHECK(it != discontinuous_spaces_.end()); 783 discontinuous_spaces_.erase(it); 784 } 785 if (space->IsAllocSpace()) { 786 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 787 DCHECK(it != alloc_spaces_.end()); 788 alloc_spaces_.erase(it); 789 } 790} 791 792void Heap::DumpGcPerformanceInfo(std::ostream& os) { 793 // Dump cumulative timings. 794 os << "Dumping cumulative Gc timings\n"; 795 uint64_t total_duration = 0; 796 // Dump cumulative loggers for each GC type. 797 uint64_t total_paused_time = 0; 798 for (auto& collector : garbage_collectors_) { 799 total_duration += collector->GetCumulativeTimings().GetTotalNs(); 800 total_paused_time += collector->GetTotalPausedTimeNs(); 801 collector->DumpPerformanceInfo(os); 802 collector->ResetMeasurements(); 803 } 804 uint64_t allocation_time = 805 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 806 if (total_duration != 0) { 807 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 808 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 809 os << "Mean GC size throughput: " 810 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 811 os << "Mean GC object throughput: " 812 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 813 } 814 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 815 os << "Total number of allocations " << total_objects_allocated << "\n"; 816 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 817 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 818 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 819 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 820 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 821 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 822 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 823 if (kMeasureAllocationTime) { 824 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 825 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 826 << "\n"; 827 } 828 if (HasZygoteSpace()) { 829 os << "Zygote space size " << PrettySize(zygote_space_->Size()) << "\n"; 830 } 831 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 832 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 833 BaseMutex::DumpAll(os); 834} 835 836Heap::~Heap() { 837 VLOG(heap) << "Starting ~Heap()"; 838 STLDeleteElements(&garbage_collectors_); 839 // If we don't reset then the mark stack complains in its destructor. 840 allocation_stack_->Reset(); 841 live_stack_->Reset(); 842 STLDeleteValues(&mod_union_tables_); 843 STLDeleteValues(&remembered_sets_); 844 STLDeleteElements(&continuous_spaces_); 845 STLDeleteElements(&discontinuous_spaces_); 846 delete gc_complete_lock_; 847 delete heap_trim_request_lock_; 848 VLOG(heap) << "Finished ~Heap()"; 849} 850 851space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 852 bool fail_ok) const { 853 for (const auto& space : continuous_spaces_) { 854 if (space->Contains(obj)) { 855 return space; 856 } 857 } 858 if (!fail_ok) { 859 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 860 } 861 return NULL; 862} 863 864space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 865 bool fail_ok) const { 866 for (const auto& space : discontinuous_spaces_) { 867 if (space->Contains(obj)) { 868 return space; 869 } 870 } 871 if (!fail_ok) { 872 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 873 } 874 return NULL; 875} 876 877space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 878 space::Space* result = FindContinuousSpaceFromObject(obj, true); 879 if (result != NULL) { 880 return result; 881 } 882 return FindDiscontinuousSpaceFromObject(obj, true); 883} 884 885space::ImageSpace* Heap::GetImageSpace() const { 886 for (const auto& space : continuous_spaces_) { 887 if (space->IsImageSpace()) { 888 return space->AsImageSpace(); 889 } 890 } 891 return NULL; 892} 893 894void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 895 std::ostringstream oss; 896 size_t total_bytes_free = GetFreeMemory(); 897 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 898 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 899 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 900 if (total_bytes_free >= byte_count) { 901 space::AllocSpace* space = nullptr; 902 if (allocator_type == kAllocatorTypeNonMoving) { 903 space = non_moving_space_; 904 } else if (allocator_type == kAllocatorTypeRosAlloc || 905 allocator_type == kAllocatorTypeDlMalloc) { 906 space = main_space_; 907 } else if (allocator_type == kAllocatorTypeBumpPointer || 908 allocator_type == kAllocatorTypeTLAB) { 909 space = bump_pointer_space_; 910 } 911 if (space != nullptr) { 912 space->LogFragmentationAllocFailure(oss, byte_count); 913 } 914 } 915 self->ThrowOutOfMemoryError(oss.str().c_str()); 916} 917 918void Heap::DoPendingTransitionOrTrim() { 919 Thread* self = Thread::Current(); 920 CollectorType desired_collector_type; 921 // Wait until we reach the desired transition time. 922 while (true) { 923 uint64_t wait_time; 924 { 925 MutexLock mu(self, *heap_trim_request_lock_); 926 desired_collector_type = desired_collector_type_; 927 uint64_t current_time = NanoTime(); 928 if (current_time >= heap_transition_or_trim_target_time_) { 929 break; 930 } 931 wait_time = heap_transition_or_trim_target_time_ - current_time; 932 } 933 ScopedThreadStateChange tsc(self, kSleeping); 934 usleep(wait_time / 1000); // Usleep takes microseconds. 935 } 936 // Launch homogeneous space compaction if it is desired. 937 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 938 if (!CareAboutPauseTimes()) { 939 PerformHomogeneousSpaceCompact(); 940 } 941 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 942 desired_collector_type = collector_type_; 943 return; 944 } 945 // Transition the collector if the desired collector type is not the same as the current 946 // collector type. 947 TransitionCollector(desired_collector_type); 948 if (!CareAboutPauseTimes()) { 949 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 950 // about pauses. 951 Runtime* runtime = Runtime::Current(); 952 runtime->GetThreadList()->SuspendAll(); 953 uint64_t start_time = NanoTime(); 954 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 955 VLOG(heap) << "Deflating " << count << " monitors took " 956 << PrettyDuration(NanoTime() - start_time); 957 runtime->GetThreadList()->ResumeAll(); 958 } 959 // Do a heap trim if it is needed. 960 Trim(); 961} 962 963void Heap::Trim() { 964 Thread* self = Thread::Current(); 965 { 966 MutexLock mu(self, *heap_trim_request_lock_); 967 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 968 return; 969 } 970 last_trim_time_ = NanoTime(); 971 heap_trim_request_pending_ = false; 972 } 973 { 974 // Need to do this before acquiring the locks since we don't want to get suspended while 975 // holding any locks. 976 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 977 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 978 // trimming. 979 MutexLock mu(self, *gc_complete_lock_); 980 // Ensure there is only one GC at a time. 981 WaitForGcToCompleteLocked(kGcCauseTrim, self); 982 collector_type_running_ = kCollectorTypeHeapTrim; 983 } 984 uint64_t start_ns = NanoTime(); 985 // Trim the managed spaces. 986 uint64_t total_alloc_space_allocated = 0; 987 uint64_t total_alloc_space_size = 0; 988 uint64_t managed_reclaimed = 0; 989 for (const auto& space : continuous_spaces_) { 990 if (space->IsMallocSpace()) { 991 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 992 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 993 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 994 // for a long period of time. 995 managed_reclaimed += malloc_space->Trim(); 996 } 997 total_alloc_space_size += malloc_space->Size(); 998 } 999 } 1000 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 1001 if (bump_pointer_space_ != nullptr) { 1002 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1003 } 1004 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1005 static_cast<float>(total_alloc_space_size); 1006 uint64_t gc_heap_end_ns = NanoTime(); 1007 // We never move things in the native heap, so we can finish the GC at this point. 1008 FinishGC(self, collector::kGcTypeNone); 1009 size_t native_reclaimed = 0; 1010 // Only trim the native heap if we don't care about pauses. 1011 if (!CareAboutPauseTimes()) { 1012#if defined(USE_DLMALLOC) 1013 // Trim the native heap. 1014 dlmalloc_trim(0); 1015 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1016#elif defined(USE_JEMALLOC) 1017 // Jemalloc does it's own internal trimming. 1018#else 1019 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1020#endif 1021 } 1022 uint64_t end_ns = NanoTime(); 1023 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1024 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1025 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1026 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1027 << "%."; 1028} 1029 1030bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1031 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1032 // taking the lock. 1033 if (obj == nullptr) { 1034 return true; 1035 } 1036 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1037} 1038 1039bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1040 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1041} 1042 1043bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1044 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1045 return false; 1046 } 1047 for (const auto& space : continuous_spaces_) { 1048 if (space->HasAddress(obj)) { 1049 return true; 1050 } 1051 } 1052 return false; 1053} 1054 1055bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1056 bool search_live_stack, bool sorted) { 1057 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1058 return false; 1059 } 1060 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1061 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1062 if (obj == klass) { 1063 // This case happens for java.lang.Class. 1064 return true; 1065 } 1066 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1067 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1068 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1069 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1070 return temp_space_->Contains(obj); 1071 } 1072 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1073 space::DiscontinuousSpace* d_space = nullptr; 1074 if (c_space != nullptr) { 1075 if (c_space->GetLiveBitmap()->Test(obj)) { 1076 return true; 1077 } 1078 } else { 1079 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1080 if (d_space != nullptr) { 1081 if (d_space->GetLiveBitmap()->Test(obj)) { 1082 return true; 1083 } 1084 } 1085 } 1086 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1087 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1088 if (i > 0) { 1089 NanoSleep(MsToNs(10)); 1090 } 1091 if (search_allocation_stack) { 1092 if (sorted) { 1093 if (allocation_stack_->ContainsSorted(obj)) { 1094 return true; 1095 } 1096 } else if (allocation_stack_->Contains(obj)) { 1097 return true; 1098 } 1099 } 1100 1101 if (search_live_stack) { 1102 if (sorted) { 1103 if (live_stack_->ContainsSorted(obj)) { 1104 return true; 1105 } 1106 } else if (live_stack_->Contains(obj)) { 1107 return true; 1108 } 1109 } 1110 } 1111 // We need to check the bitmaps again since there is a race where we mark something as live and 1112 // then clear the stack containing it. 1113 if (c_space != nullptr) { 1114 if (c_space->GetLiveBitmap()->Test(obj)) { 1115 return true; 1116 } 1117 } else { 1118 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1119 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1120 return true; 1121 } 1122 } 1123 return false; 1124} 1125 1126std::string Heap::DumpSpaces() const { 1127 std::ostringstream oss; 1128 DumpSpaces(oss); 1129 return oss.str(); 1130} 1131 1132void Heap::DumpSpaces(std::ostream& stream) const { 1133 for (const auto& space : continuous_spaces_) { 1134 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1135 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1136 stream << space << " " << *space << "\n"; 1137 if (live_bitmap != nullptr) { 1138 stream << live_bitmap << " " << *live_bitmap << "\n"; 1139 } 1140 if (mark_bitmap != nullptr) { 1141 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1142 } 1143 } 1144 for (const auto& space : discontinuous_spaces_) { 1145 stream << space << " " << *space << "\n"; 1146 } 1147} 1148 1149void Heap::VerifyObjectBody(mirror::Object* obj) { 1150 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1151 return; 1152 } 1153 1154 // Ignore early dawn of the universe verifications. 1155 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1156 return; 1157 } 1158 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1159 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1160 CHECK(c != nullptr) << "Null class in object " << obj; 1161 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1162 CHECK(VerifyClassClass(c)); 1163 1164 if (verify_object_mode_ > kVerifyObjectModeFast) { 1165 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1166 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1167 } 1168} 1169 1170void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1171 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1172} 1173 1174void Heap::VerifyHeap() { 1175 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1176 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1177} 1178 1179void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1180 // Use signed comparison since freed bytes can be negative when background compaction foreground 1181 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1182 // free list backed space typically increasing memory footprint due to padding and binning. 1183 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1184 // Note: This relies on 2s complement for handling negative freed_bytes. 1185 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1186 if (Runtime::Current()->HasStatsEnabled()) { 1187 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1188 thread_stats->freed_objects += freed_objects; 1189 thread_stats->freed_bytes += freed_bytes; 1190 // TODO: Do this concurrently. 1191 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1192 global_stats->freed_objects += freed_objects; 1193 global_stats->freed_bytes += freed_bytes; 1194 } 1195} 1196 1197space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1198 for (const auto& space : continuous_spaces_) { 1199 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1200 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1201 return space->AsContinuousSpace()->AsRosAllocSpace(); 1202 } 1203 } 1204 } 1205 return nullptr; 1206} 1207 1208mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1209 size_t alloc_size, size_t* bytes_allocated, 1210 size_t* usable_size, 1211 mirror::Class** klass) { 1212 bool was_default_allocator = allocator == GetCurrentAllocator(); 1213 // Make sure there is no pending exception since we may need to throw an OOME. 1214 self->AssertNoPendingException(); 1215 DCHECK(klass != nullptr); 1216 StackHandleScope<1> hs(self); 1217 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1218 klass = nullptr; // Invalidate for safety. 1219 // The allocation failed. If the GC is running, block until it completes, and then retry the 1220 // allocation. 1221 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1222 if (last_gc != collector::kGcTypeNone) { 1223 // If we were the default allocator but the allocator changed while we were suspended, 1224 // abort the allocation. 1225 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1226 return nullptr; 1227 } 1228 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1229 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1230 usable_size); 1231 if (ptr != nullptr) { 1232 return ptr; 1233 } 1234 } 1235 1236 collector::GcType tried_type = next_gc_type_; 1237 const bool gc_ran = 1238 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1239 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1240 return nullptr; 1241 } 1242 if (gc_ran) { 1243 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1244 usable_size); 1245 if (ptr != nullptr) { 1246 return ptr; 1247 } 1248 } 1249 1250 // Loop through our different Gc types and try to Gc until we get enough free memory. 1251 for (collector::GcType gc_type : gc_plan_) { 1252 if (gc_type == tried_type) { 1253 continue; 1254 } 1255 // Attempt to run the collector, if we succeed, re-try the allocation. 1256 const bool gc_ran = 1257 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1258 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1259 return nullptr; 1260 } 1261 if (gc_ran) { 1262 // Did we free sufficient memory for the allocation to succeed? 1263 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1264 usable_size); 1265 if (ptr != nullptr) { 1266 return ptr; 1267 } 1268 } 1269 } 1270 // Allocations have failed after GCs; this is an exceptional state. 1271 // Try harder, growing the heap if necessary. 1272 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1273 usable_size); 1274 if (ptr != nullptr) { 1275 return ptr; 1276 } 1277 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1278 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1279 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1280 // OOME. 1281 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1282 << " allocation"; 1283 // TODO: Run finalization, but this may cause more allocations to occur. 1284 // We don't need a WaitForGcToComplete here either. 1285 DCHECK(!gc_plan_.empty()); 1286 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1287 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1288 return nullptr; 1289 } 1290 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1291 if (ptr == nullptr) { 1292 const uint64_t current_time = NanoTime(); 1293 switch (allocator) { 1294 case kAllocatorTypeRosAlloc: 1295 // Fall-through. 1296 case kAllocatorTypeDlMalloc: { 1297 if (use_homogeneous_space_compaction_for_oom_ && 1298 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1299 min_interval_homogeneous_space_compaction_by_oom_) { 1300 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1301 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1302 switch (result) { 1303 case HomogeneousSpaceCompactResult::kSuccess: 1304 // If the allocation succeeded, we delayed an oom. 1305 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1306 usable_size); 1307 if (ptr != nullptr) { 1308 count_delayed_oom_++; 1309 } 1310 break; 1311 case HomogeneousSpaceCompactResult::kErrorReject: 1312 // Reject due to disabled moving GC. 1313 break; 1314 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1315 // Throw OOM by default. 1316 break; 1317 default: { 1318 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1319 << static_cast<size_t>(result); 1320 } 1321 } 1322 // Always print that we ran homogeneous space compation since this can cause jank. 1323 VLOG(heap) << "Ran heap homogeneous space compaction, " 1324 << " requested defragmentation " 1325 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1326 << " performed defragmentation " 1327 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1328 << " ignored homogeneous space compaction " 1329 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1330 << " delayed count = " 1331 << count_delayed_oom_.LoadSequentiallyConsistent(); 1332 } 1333 break; 1334 } 1335 case kAllocatorTypeNonMoving: { 1336 // Try to transition the heap if the allocation failure was due to the space being full. 1337 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1338 // If we aren't out of memory then the OOM was probably from the non moving space being 1339 // full. Attempt to disable compaction and turn the main space into a non moving space. 1340 DisableMovingGc(); 1341 // If we are still a moving GC then something must have caused the transition to fail. 1342 if (IsMovingGc(collector_type_)) { 1343 MutexLock mu(self, *gc_complete_lock_); 1344 // If we couldn't disable moving GC, just throw OOME and return null. 1345 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1346 << disable_moving_gc_count_; 1347 } else { 1348 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1349 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1350 usable_size); 1351 } 1352 } 1353 break; 1354 } 1355 default: { 1356 // Do nothing for others allocators. 1357 } 1358 } 1359 } 1360 // If the allocation hasn't succeeded by this point, throw an OOM error. 1361 if (ptr == nullptr) { 1362 ThrowOutOfMemoryError(self, alloc_size, allocator); 1363 } 1364 return ptr; 1365} 1366 1367void Heap::SetTargetHeapUtilization(float target) { 1368 DCHECK_GT(target, 0.0f); // asserted in Java code 1369 DCHECK_LT(target, 1.0f); 1370 target_utilization_ = target; 1371} 1372 1373size_t Heap::GetObjectsAllocated() const { 1374 size_t total = 0; 1375 for (space::AllocSpace* space : alloc_spaces_) { 1376 total += space->GetObjectsAllocated(); 1377 } 1378 return total; 1379} 1380 1381uint64_t Heap::GetObjectsAllocatedEver() const { 1382 return GetObjectsFreedEver() + GetObjectsAllocated(); 1383} 1384 1385uint64_t Heap::GetBytesAllocatedEver() const { 1386 return GetBytesFreedEver() + GetBytesAllocated(); 1387} 1388 1389class InstanceCounter { 1390 public: 1391 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1392 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1393 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1394 } 1395 static void Callback(mirror::Object* obj, void* arg) 1396 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1397 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1398 mirror::Class* instance_class = obj->GetClass(); 1399 CHECK(instance_class != nullptr); 1400 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1401 if (instance_counter->use_is_assignable_from_) { 1402 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1403 ++instance_counter->counts_[i]; 1404 } 1405 } else if (instance_class == instance_counter->classes_[i]) { 1406 ++instance_counter->counts_[i]; 1407 } 1408 } 1409 } 1410 1411 private: 1412 const std::vector<mirror::Class*>& classes_; 1413 bool use_is_assignable_from_; 1414 uint64_t* const counts_; 1415 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1416}; 1417 1418void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1419 uint64_t* counts) { 1420 // Can't do any GC in this function since this may move classes. 1421 Thread* self = Thread::Current(); 1422 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1423 InstanceCounter counter(classes, use_is_assignable_from, counts); 1424 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1425 VisitObjects(InstanceCounter::Callback, &counter); 1426 self->EndAssertNoThreadSuspension(old_cause); 1427} 1428 1429class InstanceCollector { 1430 public: 1431 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1432 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1433 : class_(c), max_count_(max_count), instances_(instances) { 1434 } 1435 static void Callback(mirror::Object* obj, void* arg) 1436 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1437 DCHECK(arg != nullptr); 1438 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1439 mirror::Class* instance_class = obj->GetClass(); 1440 if (instance_class == instance_collector->class_) { 1441 if (instance_collector->max_count_ == 0 || 1442 instance_collector->instances_.size() < instance_collector->max_count_) { 1443 instance_collector->instances_.push_back(obj); 1444 } 1445 } 1446 } 1447 1448 private: 1449 mirror::Class* class_; 1450 uint32_t max_count_; 1451 std::vector<mirror::Object*>& instances_; 1452 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1453}; 1454 1455void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1456 std::vector<mirror::Object*>& instances) { 1457 // Can't do any GC in this function since this may move classes. 1458 Thread* self = Thread::Current(); 1459 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1460 InstanceCollector collector(c, max_count, instances); 1461 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1462 VisitObjects(&InstanceCollector::Callback, &collector); 1463 self->EndAssertNoThreadSuspension(old_cause); 1464} 1465 1466class ReferringObjectsFinder { 1467 public: 1468 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1469 std::vector<mirror::Object*>& referring_objects) 1470 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1471 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1472 } 1473 1474 static void Callback(mirror::Object* obj, void* arg) 1475 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1476 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1477 } 1478 1479 // For bitmap Visit. 1480 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1481 // annotalysis on visitors. 1482 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1483 o->VisitReferences<true>(*this, VoidFunctor()); 1484 } 1485 1486 // For Object::VisitReferences. 1487 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1488 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1489 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1490 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1491 referring_objects_.push_back(obj); 1492 } 1493 } 1494 1495 private: 1496 mirror::Object* object_; 1497 uint32_t max_count_; 1498 std::vector<mirror::Object*>& referring_objects_; 1499 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1500}; 1501 1502void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1503 std::vector<mirror::Object*>& referring_objects) { 1504 // Can't do any GC in this function since this may move the object o. 1505 Thread* self = Thread::Current(); 1506 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1507 ReferringObjectsFinder finder(o, max_count, referring_objects); 1508 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1509 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1510 self->EndAssertNoThreadSuspension(old_cause); 1511} 1512 1513void Heap::CollectGarbage(bool clear_soft_references) { 1514 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1515 // last GC will not have necessarily been cleared. 1516 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1517} 1518 1519HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1520 Thread* self = Thread::Current(); 1521 // Inc requested homogeneous space compaction. 1522 count_requested_homogeneous_space_compaction_++; 1523 // Store performed homogeneous space compaction at a new request arrival. 1524 ThreadList* tl = Runtime::Current()->GetThreadList(); 1525 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1526 Locks::mutator_lock_->AssertNotHeld(self); 1527 { 1528 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1529 MutexLock mu(self, *gc_complete_lock_); 1530 // Ensure there is only one GC at a time. 1531 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1532 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1533 // is non zero. 1534 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1535 // exit. 1536 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1537 !main_space_->CanMoveObjects()) { 1538 return HomogeneousSpaceCompactResult::kErrorReject; 1539 } 1540 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1541 } 1542 if (Runtime::Current()->IsShuttingDown(self)) { 1543 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1544 // cause objects to get finalized. 1545 FinishGC(self, collector::kGcTypeNone); 1546 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1547 } 1548 // Suspend all threads. 1549 tl->SuspendAll(); 1550 uint64_t start_time = NanoTime(); 1551 // Launch compaction. 1552 space::MallocSpace* to_space = main_space_backup_.release(); 1553 space::MallocSpace* from_space = main_space_; 1554 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1555 const uint64_t space_size_before_compaction = from_space->Size(); 1556 AddSpace(to_space); 1557 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1558 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1559 from_space->GetMemMap()->Protect(PROT_READ); 1560 const uint64_t space_size_after_compaction = to_space->Size(); 1561 main_space_ = to_space; 1562 main_space_backup_.reset(from_space); 1563 RemoveSpace(from_space); 1564 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1565 // Update performed homogeneous space compaction count. 1566 count_performed_homogeneous_space_compaction_++; 1567 // Print statics log and resume all threads. 1568 uint64_t duration = NanoTime() - start_time; 1569 VLOG(heap) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1570 << PrettySize(space_size_before_compaction) << " -> " 1571 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1572 << std::fixed << static_cast<double>(space_size_after_compaction) / 1573 static_cast<double>(space_size_before_compaction); 1574 tl->ResumeAll(); 1575 // Finish GC. 1576 reference_processor_.EnqueueClearedReferences(self); 1577 GrowForUtilization(semi_space_collector_); 1578 FinishGC(self, collector::kGcTypeFull); 1579 return HomogeneousSpaceCompactResult::kSuccess; 1580} 1581 1582 1583void Heap::TransitionCollector(CollectorType collector_type) { 1584 if (collector_type == collector_type_) { 1585 return; 1586 } 1587 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1588 << " -> " << static_cast<int>(collector_type); 1589 uint64_t start_time = NanoTime(); 1590 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1591 Runtime* const runtime = Runtime::Current(); 1592 ThreadList* const tl = runtime->GetThreadList(); 1593 Thread* const self = Thread::Current(); 1594 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1595 Locks::mutator_lock_->AssertNotHeld(self); 1596 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1597 // compacting_gc_disable_count_, this should rarely occurs). 1598 for (;;) { 1599 { 1600 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1601 MutexLock mu(self, *gc_complete_lock_); 1602 // Ensure there is only one GC at a time. 1603 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1604 // Currently we only need a heap transition if we switch from a moving collector to a 1605 // non-moving one, or visa versa. 1606 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1607 // If someone else beat us to it and changed the collector before we could, exit. 1608 // This is safe to do before the suspend all since we set the collector_type_running_ before 1609 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1610 // then it would get blocked on WaitForGcToCompleteLocked. 1611 if (collector_type == collector_type_) { 1612 return; 1613 } 1614 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1615 if (!copying_transition || disable_moving_gc_count_ == 0) { 1616 // TODO: Not hard code in semi-space collector? 1617 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1618 break; 1619 } 1620 } 1621 usleep(1000); 1622 } 1623 if (runtime->IsShuttingDown(self)) { 1624 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1625 // cause objects to get finalized. 1626 FinishGC(self, collector::kGcTypeNone); 1627 return; 1628 } 1629 tl->SuspendAll(); 1630 switch (collector_type) { 1631 case kCollectorTypeSS: { 1632 if (!IsMovingGc(collector_type_)) { 1633 // Create the bump pointer space from the backup space. 1634 CHECK(main_space_backup_ != nullptr); 1635 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1636 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1637 // pointer space last transition it will be protected. 1638 CHECK(mem_map != nullptr); 1639 mem_map->Protect(PROT_READ | PROT_WRITE); 1640 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1641 mem_map.release()); 1642 AddSpace(bump_pointer_space_); 1643 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1644 // Use the now empty main space mem map for the bump pointer temp space. 1645 mem_map.reset(main_space_->ReleaseMemMap()); 1646 // Unset the pointers just in case. 1647 if (dlmalloc_space_ == main_space_) { 1648 dlmalloc_space_ = nullptr; 1649 } else if (rosalloc_space_ == main_space_) { 1650 rosalloc_space_ = nullptr; 1651 } 1652 // Remove the main space so that we don't try to trim it, this doens't work for debug 1653 // builds since RosAlloc attempts to read the magic number from a protected page. 1654 RemoveSpace(main_space_); 1655 RemoveRememberedSet(main_space_); 1656 delete main_space_; // Delete the space since it has been removed. 1657 main_space_ = nullptr; 1658 RemoveRememberedSet(main_space_backup_.get()); 1659 main_space_backup_.reset(nullptr); // Deletes the space. 1660 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1661 mem_map.release()); 1662 AddSpace(temp_space_); 1663 } 1664 break; 1665 } 1666 case kCollectorTypeMS: 1667 // Fall through. 1668 case kCollectorTypeCMS: { 1669 if (IsMovingGc(collector_type_)) { 1670 CHECK(temp_space_ != nullptr); 1671 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1672 RemoveSpace(temp_space_); 1673 temp_space_ = nullptr; 1674 mem_map->Protect(PROT_READ | PROT_WRITE); 1675 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1676 mem_map->Size()); 1677 mem_map.release(); 1678 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1679 AddSpace(main_space_); 1680 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1681 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1682 RemoveSpace(bump_pointer_space_); 1683 bump_pointer_space_ = nullptr; 1684 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1685 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1686 if (kIsDebugBuild && kUseRosAlloc) { 1687 mem_map->Protect(PROT_READ | PROT_WRITE); 1688 } 1689 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1690 mem_map->Size(), mem_map->Size(), 1691 name, true)); 1692 if (kIsDebugBuild && kUseRosAlloc) { 1693 mem_map->Protect(PROT_NONE); 1694 } 1695 mem_map.release(); 1696 } 1697 break; 1698 } 1699 default: { 1700 LOG(FATAL) << "Attempted to transition to invalid collector type " 1701 << static_cast<size_t>(collector_type); 1702 break; 1703 } 1704 } 1705 ChangeCollector(collector_type); 1706 tl->ResumeAll(); 1707 // Can't call into java code with all threads suspended. 1708 reference_processor_.EnqueueClearedReferences(self); 1709 uint64_t duration = NanoTime() - start_time; 1710 GrowForUtilization(semi_space_collector_); 1711 FinishGC(self, collector::kGcTypeFull); 1712 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1713 int32_t delta_allocated = before_allocated - after_allocated; 1714 std::string saved_str; 1715 if (delta_allocated >= 0) { 1716 saved_str = " saved at least " + PrettySize(delta_allocated); 1717 } else { 1718 saved_str = " expanded " + PrettySize(-delta_allocated); 1719 } 1720 VLOG(heap) << "Heap transition to " << process_state_ << " took " 1721 << PrettyDuration(duration) << saved_str; 1722} 1723 1724void Heap::ChangeCollector(CollectorType collector_type) { 1725 // TODO: Only do this with all mutators suspended to avoid races. 1726 if (collector_type != collector_type_) { 1727 if (collector_type == kCollectorTypeMC) { 1728 // Don't allow mark compact unless support is compiled in. 1729 CHECK(kMarkCompactSupport); 1730 } 1731 collector_type_ = collector_type; 1732 gc_plan_.clear(); 1733 switch (collector_type_) { 1734 case kCollectorTypeCC: // Fall-through. 1735 case kCollectorTypeMC: // Fall-through. 1736 case kCollectorTypeSS: // Fall-through. 1737 case kCollectorTypeGSS: { 1738 gc_plan_.push_back(collector::kGcTypeFull); 1739 if (use_tlab_) { 1740 ChangeAllocator(kAllocatorTypeTLAB); 1741 } else { 1742 ChangeAllocator(kAllocatorTypeBumpPointer); 1743 } 1744 break; 1745 } 1746 case kCollectorTypeMS: { 1747 gc_plan_.push_back(collector::kGcTypeSticky); 1748 gc_plan_.push_back(collector::kGcTypePartial); 1749 gc_plan_.push_back(collector::kGcTypeFull); 1750 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1751 break; 1752 } 1753 case kCollectorTypeCMS: { 1754 gc_plan_.push_back(collector::kGcTypeSticky); 1755 gc_plan_.push_back(collector::kGcTypePartial); 1756 gc_plan_.push_back(collector::kGcTypeFull); 1757 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1758 break; 1759 } 1760 default: { 1761 LOG(FATAL) << "Unimplemented"; 1762 } 1763 } 1764 if (IsGcConcurrent()) { 1765 concurrent_start_bytes_ = 1766 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1767 } else { 1768 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1769 } 1770 } 1771} 1772 1773// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1774class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1775 public: 1776 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1777 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1778 } 1779 1780 void BuildBins(space::ContinuousSpace* space) { 1781 bin_live_bitmap_ = space->GetLiveBitmap(); 1782 bin_mark_bitmap_ = space->GetMarkBitmap(); 1783 BinContext context; 1784 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1785 context.collector_ = this; 1786 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1787 // Note: This requires traversing the space in increasing order of object addresses. 1788 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1789 // Add the last bin which spans after the last object to the end of the space. 1790 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1791 } 1792 1793 private: 1794 struct BinContext { 1795 uintptr_t prev_; // The end of the previous object. 1796 ZygoteCompactingCollector* collector_; 1797 }; 1798 // Maps from bin sizes to locations. 1799 std::multimap<size_t, uintptr_t> bins_; 1800 // Live bitmap of the space which contains the bins. 1801 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1802 // Mark bitmap of the space which contains the bins. 1803 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1804 1805 static void Callback(mirror::Object* obj, void* arg) 1806 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1807 DCHECK(arg != nullptr); 1808 BinContext* context = reinterpret_cast<BinContext*>(arg); 1809 ZygoteCompactingCollector* collector = context->collector_; 1810 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1811 size_t bin_size = object_addr - context->prev_; 1812 // Add the bin consisting of the end of the previous object to the start of the current object. 1813 collector->AddBin(bin_size, context->prev_); 1814 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1815 } 1816 1817 void AddBin(size_t size, uintptr_t position) { 1818 if (size != 0) { 1819 bins_.insert(std::make_pair(size, position)); 1820 } 1821 } 1822 1823 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1824 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1825 // allocator. 1826 return false; 1827 } 1828 1829 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1830 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1831 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1832 mirror::Object* forward_address; 1833 // Find the smallest bin which we can move obj in. 1834 auto it = bins_.lower_bound(object_size); 1835 if (it == bins_.end()) { 1836 // No available space in the bins, place it in the target space instead (grows the zygote 1837 // space). 1838 size_t bytes_allocated; 1839 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1840 if (to_space_live_bitmap_ != nullptr) { 1841 to_space_live_bitmap_->Set(forward_address); 1842 } else { 1843 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1844 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1845 } 1846 } else { 1847 size_t size = it->first; 1848 uintptr_t pos = it->second; 1849 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1850 forward_address = reinterpret_cast<mirror::Object*>(pos); 1851 // Set the live and mark bits so that sweeping system weaks works properly. 1852 bin_live_bitmap_->Set(forward_address); 1853 bin_mark_bitmap_->Set(forward_address); 1854 DCHECK_GE(size, object_size); 1855 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1856 } 1857 // Copy the object over to its new location. 1858 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1859 if (kUseBakerOrBrooksReadBarrier) { 1860 obj->AssertReadBarrierPointer(); 1861 if (kUseBrooksReadBarrier) { 1862 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1863 forward_address->SetReadBarrierPointer(forward_address); 1864 } 1865 forward_address->AssertReadBarrierPointer(); 1866 } 1867 return forward_address; 1868 } 1869}; 1870 1871void Heap::UnBindBitmaps() { 1872 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1873 for (const auto& space : GetContinuousSpaces()) { 1874 if (space->IsContinuousMemMapAllocSpace()) { 1875 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1876 if (alloc_space->HasBoundBitmaps()) { 1877 alloc_space->UnBindBitmaps(); 1878 } 1879 } 1880 } 1881} 1882 1883void Heap::PreZygoteFork() { 1884 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1885 Thread* self = Thread::Current(); 1886 MutexLock mu(self, zygote_creation_lock_); 1887 // Try to see if we have any Zygote spaces. 1888 if (HasZygoteSpace()) { 1889 LOG(WARNING) << __FUNCTION__ << " called when we already have a zygote space."; 1890 return; 1891 } 1892 VLOG(heap) << "Starting PreZygoteFork"; 1893 // Trim the pages at the end of the non moving space. 1894 non_moving_space_->Trim(); 1895 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1896 // there. 1897 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1898 const bool same_space = non_moving_space_ == main_space_; 1899 if (kCompactZygote) { 1900 // Can't compact if the non moving space is the same as the main space. 1901 DCHECK(semi_space_collector_ != nullptr); 1902 // Temporarily disable rosalloc verification because the zygote 1903 // compaction will mess up the rosalloc internal metadata. 1904 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1905 ZygoteCompactingCollector zygote_collector(this); 1906 zygote_collector.BuildBins(non_moving_space_); 1907 // Create a new bump pointer space which we will compact into. 1908 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1909 non_moving_space_->Limit()); 1910 // Compact the bump pointer space to a new zygote bump pointer space. 1911 bool reset_main_space = false; 1912 if (IsMovingGc(collector_type_)) { 1913 zygote_collector.SetFromSpace(bump_pointer_space_); 1914 } else { 1915 CHECK(main_space_ != nullptr); 1916 // Copy from the main space. 1917 zygote_collector.SetFromSpace(main_space_); 1918 reset_main_space = true; 1919 } 1920 zygote_collector.SetToSpace(&target_space); 1921 zygote_collector.SetSwapSemiSpaces(false); 1922 zygote_collector.Run(kGcCauseCollectorTransition, false); 1923 if (reset_main_space) { 1924 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1925 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1926 MemMap* mem_map = main_space_->ReleaseMemMap(); 1927 RemoveSpace(main_space_); 1928 space::Space* old_main_space = main_space_; 1929 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1930 delete old_main_space; 1931 AddSpace(main_space_); 1932 } else { 1933 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1934 } 1935 if (temp_space_ != nullptr) { 1936 CHECK(temp_space_->IsEmpty()); 1937 } 1938 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1939 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1940 // Update the end and write out image. 1941 non_moving_space_->SetEnd(target_space.End()); 1942 non_moving_space_->SetLimit(target_space.Limit()); 1943 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1944 } 1945 // Change the collector to the post zygote one. 1946 ChangeCollector(foreground_collector_type_); 1947 // Save the old space so that we can remove it after we complete creating the zygote space. 1948 space::MallocSpace* old_alloc_space = non_moving_space_; 1949 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1950 // the remaining available space. 1951 // Remove the old space before creating the zygote space since creating the zygote space sets 1952 // the old alloc space's bitmaps to nullptr. 1953 RemoveSpace(old_alloc_space); 1954 if (collector::SemiSpace::kUseRememberedSet) { 1955 // Sanity bound check. 1956 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1957 // Remove the remembered set for the now zygote space (the old 1958 // non-moving space). Note now that we have compacted objects into 1959 // the zygote space, the data in the remembered set is no longer 1960 // needed. The zygote space will instead have a mod-union table 1961 // from this point on. 1962 RemoveRememberedSet(old_alloc_space); 1963 } 1964 zygote_space_ = old_alloc_space->CreateZygoteSpace("alloc space", low_memory_mode_, 1965 &non_moving_space_); 1966 CHECK(!non_moving_space_->CanMoveObjects()); 1967 if (same_space) { 1968 main_space_ = non_moving_space_; 1969 SetSpaceAsDefault(main_space_); 1970 } 1971 delete old_alloc_space; 1972 CHECK(HasZygoteSpace()) << "Failed creating zygote space"; 1973 AddSpace(zygote_space_); 1974 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1975 AddSpace(non_moving_space_); 1976 // Create the zygote space mod union table. 1977 accounting::ModUnionTable* mod_union_table = 1978 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, 1979 zygote_space_); 1980 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1981 // Set all the cards in the mod-union table since we don't know which objects contain references 1982 // to large objects. 1983 mod_union_table->SetCards(); 1984 AddModUnionTable(mod_union_table); 1985 if (collector::SemiSpace::kUseRememberedSet) { 1986 // Add a new remembered set for the post-zygote non-moving space. 1987 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1988 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1989 non_moving_space_); 1990 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1991 << "Failed to create post-zygote non-moving space remembered set"; 1992 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1993 } 1994} 1995 1996void Heap::FlushAllocStack() { 1997 MarkAllocStackAsLive(allocation_stack_.get()); 1998 allocation_stack_->Reset(); 1999} 2000 2001void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2002 accounting::ContinuousSpaceBitmap* bitmap2, 2003 accounting::LargeObjectBitmap* large_objects, 2004 accounting::ObjectStack* stack) { 2005 DCHECK(bitmap1 != nullptr); 2006 DCHECK(bitmap2 != nullptr); 2007 mirror::Object** limit = stack->End(); 2008 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2009 const mirror::Object* obj = *it; 2010 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2011 if (bitmap1->HasAddress(obj)) { 2012 bitmap1->Set(obj); 2013 } else if (bitmap2->HasAddress(obj)) { 2014 bitmap2->Set(obj); 2015 } else { 2016 large_objects->Set(obj); 2017 } 2018 } 2019 } 2020} 2021 2022void Heap::SwapSemiSpaces() { 2023 CHECK(bump_pointer_space_ != nullptr); 2024 CHECK(temp_space_ != nullptr); 2025 std::swap(bump_pointer_space_, temp_space_); 2026} 2027 2028void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2029 space::ContinuousMemMapAllocSpace* source_space, 2030 GcCause gc_cause) { 2031 CHECK(kMovingCollector); 2032 if (target_space != source_space) { 2033 // Don't swap spaces since this isn't a typical semi space collection. 2034 semi_space_collector_->SetSwapSemiSpaces(false); 2035 semi_space_collector_->SetFromSpace(source_space); 2036 semi_space_collector_->SetToSpace(target_space); 2037 semi_space_collector_->Run(gc_cause, false); 2038 } else { 2039 CHECK(target_space->IsBumpPointerSpace()) 2040 << "In-place compaction is only supported for bump pointer spaces"; 2041 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2042 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2043 } 2044} 2045 2046collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2047 bool clear_soft_references) { 2048 Thread* self = Thread::Current(); 2049 Runtime* runtime = Runtime::Current(); 2050 // If the heap can't run the GC, silently fail and return that no GC was run. 2051 switch (gc_type) { 2052 case collector::kGcTypePartial: { 2053 if (!HasZygoteSpace()) { 2054 return collector::kGcTypeNone; 2055 } 2056 break; 2057 } 2058 default: { 2059 // Other GC types don't have any special cases which makes them not runnable. The main case 2060 // here is full GC. 2061 } 2062 } 2063 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2064 Locks::mutator_lock_->AssertNotHeld(self); 2065 if (self->IsHandlingStackOverflow()) { 2066 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2067 } 2068 bool compacting_gc; 2069 { 2070 gc_complete_lock_->AssertNotHeld(self); 2071 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2072 MutexLock mu(self, *gc_complete_lock_); 2073 // Ensure there is only one GC at a time. 2074 WaitForGcToCompleteLocked(gc_cause, self); 2075 compacting_gc = IsMovingGc(collector_type_); 2076 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2077 if (compacting_gc && disable_moving_gc_count_ != 0) { 2078 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2079 return collector::kGcTypeNone; 2080 } 2081 collector_type_running_ = collector_type_; 2082 } 2083 2084 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2085 ++runtime->GetStats()->gc_for_alloc_count; 2086 ++self->GetStats()->gc_for_alloc_count; 2087 } 2088 uint64_t gc_start_time_ns = NanoTime(); 2089 uint64_t gc_start_size = GetBytesAllocated(); 2090 // Approximate allocation rate in bytes / second. 2091 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2092 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2093 if (LIKELY(ms_delta != 0)) { 2094 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2095 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2096 } 2097 2098 DCHECK_LT(gc_type, collector::kGcTypeMax); 2099 DCHECK_NE(gc_type, collector::kGcTypeNone); 2100 2101 collector::GarbageCollector* collector = nullptr; 2102 // TODO: Clean this up. 2103 if (compacting_gc) { 2104 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2105 current_allocator_ == kAllocatorTypeTLAB); 2106 switch (collector_type_) { 2107 case kCollectorTypeSS: 2108 // Fall-through. 2109 case kCollectorTypeGSS: 2110 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2111 semi_space_collector_->SetToSpace(temp_space_); 2112 semi_space_collector_->SetSwapSemiSpaces(true); 2113 collector = semi_space_collector_; 2114 break; 2115 case kCollectorTypeCC: 2116 collector = concurrent_copying_collector_; 2117 break; 2118 case kCollectorTypeMC: 2119 mark_compact_collector_->SetSpace(bump_pointer_space_); 2120 collector = mark_compact_collector_; 2121 break; 2122 default: 2123 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2124 } 2125 if (collector != mark_compact_collector_) { 2126 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2127 CHECK(temp_space_->IsEmpty()); 2128 } 2129 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2130 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2131 current_allocator_ == kAllocatorTypeDlMalloc) { 2132 collector = FindCollectorByGcType(gc_type); 2133 } else { 2134 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2135 } 2136 CHECK(collector != nullptr) 2137 << "Could not find garbage collector with collector_type=" 2138 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2139 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2140 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2141 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2142 RequestHeapTrim(); 2143 // Enqueue cleared references. 2144 reference_processor_.EnqueueClearedReferences(self); 2145 // Grow the heap so that we know when to perform the next GC. 2146 GrowForUtilization(collector); 2147 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2148 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2149 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2150 // (mutator time blocked >= long_pause_log_threshold_). 2151 bool log_gc = gc_cause == kGcCauseExplicit; 2152 if (!log_gc && CareAboutPauseTimes()) { 2153 // GC for alloc pauses the allocating thread, so consider it as a pause. 2154 log_gc = duration > long_gc_log_threshold_ || 2155 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2156 for (uint64_t pause : pause_times) { 2157 log_gc = log_gc || pause >= long_pause_log_threshold_; 2158 } 2159 } 2160 if (log_gc) { 2161 const size_t percent_free = GetPercentFree(); 2162 const size_t current_heap_size = GetBytesAllocated(); 2163 const size_t total_memory = GetTotalMemory(); 2164 std::ostringstream pause_string; 2165 for (size_t i = 0; i < pause_times.size(); ++i) { 2166 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2167 << ((i != pause_times.size() - 1) ? "," : ""); 2168 } 2169 LOG(INFO) << gc_cause << " " << collector->GetName() 2170 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2171 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2172 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2173 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2174 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2175 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2176 << " total " << PrettyDuration((duration / 1000) * 1000); 2177 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2178 } 2179 FinishGC(self, gc_type); 2180 // Inform DDMS that a GC completed. 2181 Dbg::GcDidFinish(); 2182 return gc_type; 2183} 2184 2185void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2186 MutexLock mu(self, *gc_complete_lock_); 2187 collector_type_running_ = kCollectorTypeNone; 2188 if (gc_type != collector::kGcTypeNone) { 2189 last_gc_type_ = gc_type; 2190 } 2191 // Wake anyone who may have been waiting for the GC to complete. 2192 gc_complete_cond_->Broadcast(self); 2193} 2194 2195static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2196 RootType /*root_type*/) { 2197 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2198 if (*root == obj) { 2199 LOG(INFO) << "Object " << obj << " is a root"; 2200 } 2201} 2202 2203class ScanVisitor { 2204 public: 2205 void operator()(const mirror::Object* obj) const { 2206 LOG(ERROR) << "Would have rescanned object " << obj; 2207 } 2208}; 2209 2210// Verify a reference from an object. 2211class VerifyReferenceVisitor { 2212 public: 2213 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2214 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2215 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2216 2217 size_t GetFailureCount() const { 2218 return fail_count_->LoadSequentiallyConsistent(); 2219 } 2220 2221 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2222 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2223 if (verify_referent_) { 2224 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2225 } 2226 } 2227 2228 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2229 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2230 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2231 } 2232 2233 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2234 return heap_->IsLiveObjectLocked(obj, true, false, true); 2235 } 2236 2237 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2238 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2239 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2240 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2241 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2242 << " thread_id= " << thread_id << " root_type= " << root_type; 2243 } 2244 } 2245 2246 private: 2247 // TODO: Fix the no thread safety analysis. 2248 // Returns false on failure. 2249 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2250 NO_THREAD_SAFETY_ANALYSIS { 2251 if (ref == nullptr || IsLive(ref)) { 2252 // Verify that the reference is live. 2253 return true; 2254 } 2255 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2256 // Print message on only on first failure to prevent spam. 2257 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2258 } 2259 if (obj != nullptr) { 2260 // Only do this part for non roots. 2261 accounting::CardTable* card_table = heap_->GetCardTable(); 2262 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2263 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2264 byte* card_addr = card_table->CardFromAddr(obj); 2265 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2266 << offset << "\n card value = " << static_cast<int>(*card_addr); 2267 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2268 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2269 } else { 2270 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2271 } 2272 2273 // Attempt to find the class inside of the recently freed objects. 2274 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2275 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2276 space::MallocSpace* space = ref_space->AsMallocSpace(); 2277 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2278 if (ref_class != nullptr) { 2279 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2280 << PrettyClass(ref_class); 2281 } else { 2282 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2283 } 2284 } 2285 2286 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2287 ref->GetClass()->IsClass()) { 2288 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2289 } else { 2290 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2291 << ") is not a valid heap address"; 2292 } 2293 2294 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2295 void* cover_begin = card_table->AddrFromCard(card_addr); 2296 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2297 accounting::CardTable::kCardSize); 2298 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2299 << "-" << cover_end; 2300 accounting::ContinuousSpaceBitmap* bitmap = 2301 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2302 2303 if (bitmap == nullptr) { 2304 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2305 if (!VerifyClassClass(obj->GetClass())) { 2306 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2307 } 2308 } else { 2309 // Print out how the object is live. 2310 if (bitmap->Test(obj)) { 2311 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2312 } 2313 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2314 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2315 } 2316 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2317 LOG(ERROR) << "Object " << obj << " found in live stack"; 2318 } 2319 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2320 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2321 } 2322 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2323 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2324 } 2325 // Attempt to see if the card table missed the reference. 2326 ScanVisitor scan_visitor; 2327 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2328 card_table->Scan(bitmap, byte_cover_begin, 2329 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2330 } 2331 2332 // Search to see if any of the roots reference our object. 2333 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2334 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2335 2336 // Search to see if any of the roots reference our reference. 2337 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2338 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2339 } 2340 return false; 2341 } 2342 2343 Heap* const heap_; 2344 Atomic<size_t>* const fail_count_; 2345 const bool verify_referent_; 2346}; 2347 2348// Verify all references within an object, for use with HeapBitmap::Visit. 2349class VerifyObjectVisitor { 2350 public: 2351 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2352 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2353 } 2354 2355 void operator()(mirror::Object* obj) const 2356 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2357 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2358 // be live or else how did we find it in the live bitmap? 2359 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2360 // The class doesn't count as a reference but we should verify it anyways. 2361 obj->VisitReferences<true>(visitor, visitor); 2362 } 2363 2364 static void VisitCallback(mirror::Object* obj, void* arg) 2365 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2366 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2367 visitor->operator()(obj); 2368 } 2369 2370 size_t GetFailureCount() const { 2371 return fail_count_->LoadSequentiallyConsistent(); 2372 } 2373 2374 private: 2375 Heap* const heap_; 2376 Atomic<size_t>* const fail_count_; 2377 const bool verify_referent_; 2378}; 2379 2380void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2381 // Slow path, the allocation stack push back must have already failed. 2382 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2383 do { 2384 // TODO: Add handle VerifyObject. 2385 StackHandleScope<1> hs(self); 2386 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2387 // Push our object into the reserve region of the allocaiton stack. This is only required due 2388 // to heap verification requiring that roots are live (either in the live bitmap or in the 2389 // allocation stack). 2390 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2391 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2392 } while (!allocation_stack_->AtomicPushBack(*obj)); 2393} 2394 2395void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2396 // Slow path, the allocation stack push back must have already failed. 2397 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2398 mirror::Object** start_address; 2399 mirror::Object** end_address; 2400 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2401 &end_address)) { 2402 // TODO: Add handle VerifyObject. 2403 StackHandleScope<1> hs(self); 2404 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2405 // Push our object into the reserve region of the allocaiton stack. This is only required due 2406 // to heap verification requiring that roots are live (either in the live bitmap or in the 2407 // allocation stack). 2408 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2409 // Push into the reserve allocation stack. 2410 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2411 } 2412 self->SetThreadLocalAllocationStack(start_address, end_address); 2413 // Retry on the new thread-local allocation stack. 2414 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2415} 2416 2417// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2418size_t Heap::VerifyHeapReferences(bool verify_referents) { 2419 Thread* self = Thread::Current(); 2420 Locks::mutator_lock_->AssertExclusiveHeld(self); 2421 // Lets sort our allocation stacks so that we can efficiently binary search them. 2422 allocation_stack_->Sort(); 2423 live_stack_->Sort(); 2424 // Since we sorted the allocation stack content, need to revoke all 2425 // thread-local allocation stacks. 2426 RevokeAllThreadLocalAllocationStacks(self); 2427 Atomic<size_t> fail_count_(0); 2428 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2429 // Verify objects in the allocation stack since these will be objects which were: 2430 // 1. Allocated prior to the GC (pre GC verification). 2431 // 2. Allocated during the GC (pre sweep GC verification). 2432 // We don't want to verify the objects in the live stack since they themselves may be 2433 // pointing to dead objects if they are not reachable. 2434 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2435 // Verify the roots: 2436 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2437 if (visitor.GetFailureCount() > 0) { 2438 // Dump mod-union tables. 2439 for (const auto& table_pair : mod_union_tables_) { 2440 accounting::ModUnionTable* mod_union_table = table_pair.second; 2441 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2442 } 2443 // Dump remembered sets. 2444 for (const auto& table_pair : remembered_sets_) { 2445 accounting::RememberedSet* remembered_set = table_pair.second; 2446 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2447 } 2448 DumpSpaces(LOG(ERROR)); 2449 } 2450 return visitor.GetFailureCount(); 2451} 2452 2453class VerifyReferenceCardVisitor { 2454 public: 2455 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2456 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2457 Locks::heap_bitmap_lock_) 2458 : heap_(heap), failed_(failed) { 2459 } 2460 2461 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2462 // annotalysis on visitors. 2463 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2464 NO_THREAD_SAFETY_ANALYSIS { 2465 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2466 // Filter out class references since changing an object's class does not mark the card as dirty. 2467 // Also handles large objects, since the only reference they hold is a class reference. 2468 if (ref != nullptr && !ref->IsClass()) { 2469 accounting::CardTable* card_table = heap_->GetCardTable(); 2470 // If the object is not dirty and it is referencing something in the live stack other than 2471 // class, then it must be on a dirty card. 2472 if (!card_table->AddrIsInCardTable(obj)) { 2473 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2474 *failed_ = true; 2475 } else if (!card_table->IsDirty(obj)) { 2476 // TODO: Check mod-union tables. 2477 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2478 // kCardDirty - 1 if it didnt get touched since we aged it. 2479 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2480 if (live_stack->ContainsSorted(ref)) { 2481 if (live_stack->ContainsSorted(obj)) { 2482 LOG(ERROR) << "Object " << obj << " found in live stack"; 2483 } 2484 if (heap_->GetLiveBitmap()->Test(obj)) { 2485 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2486 } 2487 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2488 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2489 2490 // Print which field of the object is dead. 2491 if (!obj->IsObjectArray()) { 2492 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2493 CHECK(klass != NULL); 2494 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2495 : klass->GetIFields(); 2496 CHECK(fields != NULL); 2497 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2498 mirror::ArtField* cur = fields->Get(i); 2499 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2500 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2501 << PrettyField(cur); 2502 break; 2503 } 2504 } 2505 } else { 2506 mirror::ObjectArray<mirror::Object>* object_array = 2507 obj->AsObjectArray<mirror::Object>(); 2508 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2509 if (object_array->Get(i) == ref) { 2510 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2511 } 2512 } 2513 } 2514 2515 *failed_ = true; 2516 } 2517 } 2518 } 2519 } 2520 2521 private: 2522 Heap* const heap_; 2523 bool* const failed_; 2524}; 2525 2526class VerifyLiveStackReferences { 2527 public: 2528 explicit VerifyLiveStackReferences(Heap* heap) 2529 : heap_(heap), 2530 failed_(false) {} 2531 2532 void operator()(mirror::Object* obj) const 2533 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2534 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2535 obj->VisitReferences<true>(visitor, VoidFunctor()); 2536 } 2537 2538 bool Failed() const { 2539 return failed_; 2540 } 2541 2542 private: 2543 Heap* const heap_; 2544 bool failed_; 2545}; 2546 2547bool Heap::VerifyMissingCardMarks() { 2548 Thread* self = Thread::Current(); 2549 Locks::mutator_lock_->AssertExclusiveHeld(self); 2550 // We need to sort the live stack since we binary search it. 2551 live_stack_->Sort(); 2552 // Since we sorted the allocation stack content, need to revoke all 2553 // thread-local allocation stacks. 2554 RevokeAllThreadLocalAllocationStacks(self); 2555 VerifyLiveStackReferences visitor(this); 2556 GetLiveBitmap()->Visit(visitor); 2557 // We can verify objects in the live stack since none of these should reference dead objects. 2558 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2559 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2560 visitor(*it); 2561 } 2562 } 2563 return !visitor.Failed(); 2564} 2565 2566void Heap::SwapStacks(Thread* self) { 2567 if (kUseThreadLocalAllocationStack) { 2568 live_stack_->AssertAllZero(); 2569 } 2570 allocation_stack_.swap(live_stack_); 2571} 2572 2573void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2574 // This must be called only during the pause. 2575 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2576 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2577 MutexLock mu2(self, *Locks::thread_list_lock_); 2578 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2579 for (Thread* t : thread_list) { 2580 t->RevokeThreadLocalAllocationStack(); 2581 } 2582} 2583 2584void Heap::AssertThreadLocalBuffersAreRevoked(Thread* thread) { 2585 if (kIsDebugBuild) { 2586 if (rosalloc_space_ != nullptr) { 2587 rosalloc_space_->AssertThreadLocalBuffersAreRevoked(thread); 2588 } 2589 if (bump_pointer_space_ != nullptr) { 2590 bump_pointer_space_->AssertThreadLocalBuffersAreRevoked(thread); 2591 } 2592 } 2593} 2594 2595void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2596 if (kIsDebugBuild) { 2597 if (bump_pointer_space_ != nullptr) { 2598 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2599 } 2600 } 2601} 2602 2603accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2604 auto it = mod_union_tables_.find(space); 2605 if (it == mod_union_tables_.end()) { 2606 return nullptr; 2607 } 2608 return it->second; 2609} 2610 2611accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2612 auto it = remembered_sets_.find(space); 2613 if (it == remembered_sets_.end()) { 2614 return nullptr; 2615 } 2616 return it->second; 2617} 2618 2619void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2620 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2621 // Clear cards and keep track of cards cleared in the mod-union table. 2622 for (const auto& space : continuous_spaces_) { 2623 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2624 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2625 if (table != nullptr) { 2626 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2627 "ImageModUnionClearCards"; 2628 TimingLogger::ScopedTiming t(name, timings); 2629 table->ClearCards(); 2630 } else if (use_rem_sets && rem_set != nullptr) { 2631 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2632 << static_cast<int>(collector_type_); 2633 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2634 rem_set->ClearCards(); 2635 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2636 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2637 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2638 // were dirty before the GC started. 2639 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2640 // -> clean(cleaning thread). 2641 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2642 // roots and then we scan / update mod union tables after. We will always scan either card. 2643 // If we end up with the non aged card, we scan it it in the pause. 2644 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2645 VoidFunctor()); 2646 } 2647 } 2648} 2649 2650static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2651} 2652 2653void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2654 Thread* const self = Thread::Current(); 2655 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2656 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2657 if (verify_pre_gc_heap_) { 2658 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2659 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2660 size_t failures = VerifyHeapReferences(); 2661 if (failures > 0) { 2662 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2663 << " failures"; 2664 } 2665 } 2666 // Check that all objects which reference things in the live stack are on dirty cards. 2667 if (verify_missing_card_marks_) { 2668 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2669 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2670 SwapStacks(self); 2671 // Sort the live stack so that we can quickly binary search it later. 2672 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2673 << " missing card mark verification failed\n" << DumpSpaces(); 2674 SwapStacks(self); 2675 } 2676 if (verify_mod_union_table_) { 2677 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2678 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2679 for (const auto& table_pair : mod_union_tables_) { 2680 accounting::ModUnionTable* mod_union_table = table_pair.second; 2681 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2682 mod_union_table->Verify(); 2683 } 2684 } 2685} 2686 2687void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2688 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2689 collector::GarbageCollector::ScopedPause pause(gc); 2690 PreGcVerificationPaused(gc); 2691 } 2692} 2693 2694void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2695 // TODO: Add a new runtime option for this? 2696 if (verify_pre_gc_rosalloc_) { 2697 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2698 } 2699} 2700 2701void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2702 Thread* const self = Thread::Current(); 2703 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2704 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2705 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2706 // reachable objects. 2707 if (verify_pre_sweeping_heap_) { 2708 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2709 CHECK_NE(self->GetState(), kRunnable); 2710 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2711 // Swapping bound bitmaps does nothing. 2712 gc->SwapBitmaps(); 2713 // Pass in false since concurrent reference processing can mean that the reference referents 2714 // may point to dead objects at the point which PreSweepingGcVerification is called. 2715 size_t failures = VerifyHeapReferences(false); 2716 if (failures > 0) { 2717 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2718 << " failures"; 2719 } 2720 gc->SwapBitmaps(); 2721 } 2722 if (verify_pre_sweeping_rosalloc_) { 2723 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2724 } 2725} 2726 2727void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2728 // Only pause if we have to do some verification. 2729 Thread* const self = Thread::Current(); 2730 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2731 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2732 if (verify_system_weaks_) { 2733 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2734 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2735 mark_sweep->VerifySystemWeaks(); 2736 } 2737 if (verify_post_gc_rosalloc_) { 2738 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2739 } 2740 if (verify_post_gc_heap_) { 2741 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2742 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2743 size_t failures = VerifyHeapReferences(); 2744 if (failures > 0) { 2745 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2746 << " failures"; 2747 } 2748 } 2749} 2750 2751void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2752 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2753 collector::GarbageCollector::ScopedPause pause(gc); 2754 PostGcVerificationPaused(gc); 2755 } 2756} 2757 2758void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2759 TimingLogger::ScopedTiming t(name, timings); 2760 for (const auto& space : continuous_spaces_) { 2761 if (space->IsRosAllocSpace()) { 2762 VLOG(heap) << name << " : " << space->GetName(); 2763 space->AsRosAllocSpace()->Verify(); 2764 } 2765 } 2766} 2767 2768collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2769 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2770 MutexLock mu(self, *gc_complete_lock_); 2771 return WaitForGcToCompleteLocked(cause, self); 2772} 2773 2774collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2775 collector::GcType last_gc_type = collector::kGcTypeNone; 2776 uint64_t wait_start = NanoTime(); 2777 while (collector_type_running_ != kCollectorTypeNone) { 2778 ATRACE_BEGIN("GC: Wait For Completion"); 2779 // We must wait, change thread state then sleep on gc_complete_cond_; 2780 gc_complete_cond_->Wait(self); 2781 last_gc_type = last_gc_type_; 2782 ATRACE_END(); 2783 } 2784 uint64_t wait_time = NanoTime() - wait_start; 2785 total_wait_time_ += wait_time; 2786 if (wait_time > long_pause_log_threshold_) { 2787 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2788 << " for cause " << cause; 2789 } 2790 return last_gc_type; 2791} 2792 2793void Heap::DumpForSigQuit(std::ostream& os) { 2794 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2795 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2796 DumpGcPerformanceInfo(os); 2797} 2798 2799size_t Heap::GetPercentFree() { 2800 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2801} 2802 2803void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2804 if (max_allowed_footprint > GetMaxMemory()) { 2805 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2806 << PrettySize(GetMaxMemory()); 2807 max_allowed_footprint = GetMaxMemory(); 2808 } 2809 max_allowed_footprint_ = max_allowed_footprint; 2810} 2811 2812bool Heap::IsMovableObject(const mirror::Object* obj) const { 2813 if (kMovingCollector) { 2814 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2815 if (space != nullptr) { 2816 // TODO: Check large object? 2817 return space->CanMoveObjects(); 2818 } 2819 } 2820 return false; 2821} 2822 2823void Heap::UpdateMaxNativeFootprint() { 2824 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2825 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2826 size_t target_size = native_size / GetTargetHeapUtilization(); 2827 if (target_size > native_size + max_free_) { 2828 target_size = native_size + max_free_; 2829 } else if (target_size < native_size + min_free_) { 2830 target_size = native_size + min_free_; 2831 } 2832 native_footprint_gc_watermark_ = std::min(growth_limit_, target_size); 2833} 2834 2835collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2836 for (const auto& collector : garbage_collectors_) { 2837 if (collector->GetCollectorType() == collector_type_ && 2838 collector->GetGcType() == gc_type) { 2839 return collector; 2840 } 2841 } 2842 return nullptr; 2843} 2844 2845double Heap::HeapGrowthMultiplier() const { 2846 // If we don't care about pause times we are background, so return 1.0. 2847 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2848 return 1.0; 2849 } 2850 return foreground_heap_growth_multiplier_; 2851} 2852 2853void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2854 // We know what our utilization is at this moment. 2855 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2856 const uint64_t bytes_allocated = GetBytesAllocated(); 2857 last_gc_size_ = bytes_allocated; 2858 last_gc_time_ns_ = NanoTime(); 2859 uint64_t target_size; 2860 collector::GcType gc_type = collector_ran->GetGcType(); 2861 if (gc_type != collector::kGcTypeSticky) { 2862 // Grow the heap for non sticky GC. 2863 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2864 // foreground. 2865 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2866 CHECK_GE(delta, 0); 2867 target_size = bytes_allocated + delta * multiplier; 2868 target_size = std::min(target_size, 2869 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2870 target_size = std::max(target_size, 2871 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2872 native_need_to_run_finalization_ = true; 2873 next_gc_type_ = collector::kGcTypeSticky; 2874 } else { 2875 collector::GcType non_sticky_gc_type = 2876 HasZygoteSpace() ? collector::kGcTypePartial : collector::kGcTypeFull; 2877 // Find what the next non sticky collector will be. 2878 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2879 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2880 // do another sticky collection next. 2881 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2882 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2883 // if the sticky GC throughput always remained >= the full/partial throughput. 2884 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2885 non_sticky_collector->GetEstimatedMeanThroughput() && 2886 non_sticky_collector->NumberOfIterations() > 0 && 2887 bytes_allocated <= max_allowed_footprint_) { 2888 next_gc_type_ = collector::kGcTypeSticky; 2889 } else { 2890 next_gc_type_ = non_sticky_gc_type; 2891 } 2892 // If we have freed enough memory, shrink the heap back down. 2893 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2894 target_size = bytes_allocated + max_free_; 2895 } else { 2896 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2897 } 2898 } 2899 if (!ignore_max_footprint_) { 2900 SetIdealFootprint(target_size); 2901 if (IsGcConcurrent()) { 2902 // Calculate when to perform the next ConcurrentGC. 2903 // Calculate the estimated GC duration. 2904 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2905 // Estimate how many remaining bytes we will have when we need to start the next GC. 2906 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2907 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2908 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2909 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2910 // A never going to happen situation that from the estimated allocation rate we will exceed 2911 // the applications entire footprint with the given estimated allocation rate. Schedule 2912 // another GC nearly straight away. 2913 remaining_bytes = kMinConcurrentRemainingBytes; 2914 } 2915 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2916 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2917 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2918 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2919 // right away. 2920 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2921 static_cast<size_t>(bytes_allocated)); 2922 } 2923 } 2924} 2925 2926void Heap::ClearGrowthLimit() { 2927 growth_limit_ = capacity_; 2928 non_moving_space_->ClearGrowthLimit(); 2929} 2930 2931void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2932 ScopedObjectAccess soa(self); 2933 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2934 jvalue args[1]; 2935 args[0].l = arg.get(); 2936 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2937 // Restore object in case it gets moved. 2938 *object = soa.Decode<mirror::Object*>(arg.get()); 2939} 2940 2941void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2942 StackHandleScope<1> hs(self); 2943 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2944 RequestConcurrentGC(self); 2945} 2946 2947void Heap::RequestConcurrentGC(Thread* self) { 2948 // Make sure that we can do a concurrent GC. 2949 Runtime* runtime = Runtime::Current(); 2950 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2951 self->IsHandlingStackOverflow()) { 2952 return; 2953 } 2954 // We already have a request pending, no reason to start more until we update 2955 // concurrent_start_bytes_. 2956 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2957 JNIEnv* env = self->GetJniEnv(); 2958 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2959 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2960 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2961 WellKnownClasses::java_lang_Daemons_requestGC); 2962 CHECK(!env->ExceptionCheck()); 2963} 2964 2965void Heap::ConcurrentGC(Thread* self) { 2966 if (Runtime::Current()->IsShuttingDown(self)) { 2967 return; 2968 } 2969 // Wait for any GCs currently running to finish. 2970 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2971 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2972 // instead. E.g. can't do partial, so do full instead. 2973 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2974 collector::kGcTypeNone) { 2975 for (collector::GcType gc_type : gc_plan_) { 2976 // Attempt to run the collector, if we succeed, we are done. 2977 if (gc_type > next_gc_type_ && 2978 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2979 break; 2980 } 2981 } 2982 } 2983 } 2984} 2985 2986void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2987 Thread* self = Thread::Current(); 2988 { 2989 MutexLock mu(self, *heap_trim_request_lock_); 2990 if (desired_collector_type_ == desired_collector_type) { 2991 return; 2992 } 2993 heap_transition_or_trim_target_time_ = 2994 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 2995 desired_collector_type_ = desired_collector_type; 2996 } 2997 SignalHeapTrimDaemon(self); 2998} 2999 3000void Heap::RequestHeapTrim() { 3001 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 3002 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 3003 // a space it will hold its lock and can become a cause of jank. 3004 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 3005 // forking. 3006 3007 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 3008 // because that only marks object heads, so a large array looks like lots of empty space. We 3009 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 3010 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3011 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3012 // not how much use we're making of those pages. 3013 3014 Thread* self = Thread::Current(); 3015 Runtime* runtime = Runtime::Current(); 3016 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 3017 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3018 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3019 // as we don't hold the lock while requesting the trim). 3020 return; 3021 } 3022 { 3023 MutexLock mu(self, *heap_trim_request_lock_); 3024 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3025 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3026 // just yet. 3027 return; 3028 } 3029 heap_trim_request_pending_ = true; 3030 uint64_t current_time = NanoTime(); 3031 if (heap_transition_or_trim_target_time_ < current_time) { 3032 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 3033 } 3034 } 3035 // Notify the daemon thread which will actually do the heap trim. 3036 SignalHeapTrimDaemon(self); 3037} 3038 3039void Heap::SignalHeapTrimDaemon(Thread* self) { 3040 JNIEnv* env = self->GetJniEnv(); 3041 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3042 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3043 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3044 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3045 CHECK(!env->ExceptionCheck()); 3046} 3047 3048void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3049 if (rosalloc_space_ != nullptr) { 3050 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3051 } 3052 if (bump_pointer_space_ != nullptr) { 3053 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3054 } 3055} 3056 3057void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3058 if (rosalloc_space_ != nullptr) { 3059 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3060 } 3061} 3062 3063void Heap::RevokeAllThreadLocalBuffers() { 3064 if (rosalloc_space_ != nullptr) { 3065 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3066 } 3067 if (bump_pointer_space_ != nullptr) { 3068 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3069 } 3070} 3071 3072bool Heap::IsGCRequestPending() const { 3073 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3074} 3075 3076void Heap::RunFinalization(JNIEnv* env) { 3077 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3078 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3079 CHECK(WellKnownClasses::java_lang_System != nullptr); 3080 WellKnownClasses::java_lang_System_runFinalization = 3081 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3082 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3083 } 3084 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3085 WellKnownClasses::java_lang_System_runFinalization); 3086} 3087 3088void Heap::RegisterNativeAllocation(JNIEnv* env, size_t bytes) { 3089 Thread* self = ThreadForEnv(env); 3090 if (native_need_to_run_finalization_) { 3091 RunFinalization(env); 3092 UpdateMaxNativeFootprint(); 3093 native_need_to_run_finalization_ = false; 3094 } 3095 // Total number of native bytes allocated. 3096 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3097 new_native_bytes_allocated += bytes; 3098 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3099 collector::GcType gc_type = HasZygoteSpace() ? collector::kGcTypePartial : 3100 collector::kGcTypeFull; 3101 3102 // The second watermark is higher than the gc watermark. If you hit this it means you are 3103 // allocating native objects faster than the GC can keep up with. 3104 if (new_native_bytes_allocated > growth_limit_) { 3105 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3106 // Just finished a GC, attempt to run finalizers. 3107 RunFinalization(env); 3108 CHECK(!env->ExceptionCheck()); 3109 } 3110 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3111 if (new_native_bytes_allocated > growth_limit_) { 3112 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3113 RunFinalization(env); 3114 native_need_to_run_finalization_ = false; 3115 CHECK(!env->ExceptionCheck()); 3116 } 3117 // We have just run finalizers, update the native watermark since it is very likely that 3118 // finalizers released native managed allocations. 3119 UpdateMaxNativeFootprint(); 3120 } else if (!IsGCRequestPending()) { 3121 if (IsGcConcurrent()) { 3122 RequestConcurrentGC(self); 3123 } else { 3124 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3125 } 3126 } 3127 } 3128} 3129 3130void Heap::RegisterNativeFree(JNIEnv* env, size_t bytes) { 3131 size_t expected_size; 3132 do { 3133 expected_size = native_bytes_allocated_.LoadRelaxed(); 3134 if (UNLIKELY(bytes > expected_size)) { 3135 ScopedObjectAccess soa(env); 3136 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3137 StringPrintf("Attempted to free %zd native bytes with only %zd native bytes " 3138 "registered as allocated", bytes, expected_size).c_str()); 3139 break; 3140 } 3141 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, 3142 expected_size - bytes)); 3143} 3144 3145size_t Heap::GetTotalMemory() const { 3146 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3147} 3148 3149void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3150 DCHECK(mod_union_table != nullptr); 3151 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3152} 3153 3154void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3155 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3156 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3157 CHECK_GE(byte_count, sizeof(mirror::Object)); 3158} 3159 3160void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3161 CHECK(remembered_set != nullptr); 3162 space::Space* space = remembered_set->GetSpace(); 3163 CHECK(space != nullptr); 3164 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3165 remembered_sets_.Put(space, remembered_set); 3166 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3167} 3168 3169void Heap::RemoveRememberedSet(space::Space* space) { 3170 CHECK(space != nullptr); 3171 auto it = remembered_sets_.find(space); 3172 CHECK(it != remembered_sets_.end()); 3173 delete it->second; 3174 remembered_sets_.erase(it); 3175 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3176} 3177 3178void Heap::ClearMarkedObjects() { 3179 // Clear all of the spaces' mark bitmaps. 3180 for (const auto& space : GetContinuousSpaces()) { 3181 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3182 if (space->GetLiveBitmap() != mark_bitmap) { 3183 mark_bitmap->Clear(); 3184 } 3185 } 3186 // Clear the marked objects in the discontinous space object sets. 3187 for (const auto& space : GetDiscontinuousSpaces()) { 3188 space->GetMarkBitmap()->Clear(); 3189 } 3190} 3191 3192} // namespace gc 3193} // namespace art 3194