heap.cc revision 0ab56e95e203806dae347056d3331a3e6037457d
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/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/remembered_set.h" 37#include "gc/accounting/space_bitmap-inl.h" 38#include "gc/collector/concurrent_copying.h" 39#include "gc/collector/mark_compact.h" 40#include "gc/collector/mark_sweep-inl.h" 41#include "gc/collector/partial_mark_sweep.h" 42#include "gc/collector/semi_space.h" 43#include "gc/collector/sticky_mark_sweep.h" 44#include "gc/reference_processor.h" 45#include "gc/space/bump_pointer_space.h" 46#include "gc/space/dlmalloc_space-inl.h" 47#include "gc/space/image_space.h" 48#include "gc/space/large_object_space.h" 49#include "gc/space/rosalloc_space-inl.h" 50#include "gc/space/space-inl.h" 51#include "gc/space/zygote_space.h" 52#include "entrypoints/quick/quick_alloc_entrypoints.h" 53#include "heap-inl.h" 54#include "image.h" 55#include "mirror/art_field-inl.h" 56#include "mirror/class-inl.h" 57#include "mirror/object.h" 58#include "mirror/object-inl.h" 59#include "mirror/object_array-inl.h" 60#include "mirror/reference-inl.h" 61#include "os.h" 62#include "reflection.h" 63#include "runtime.h" 64#include "ScopedLocalRef.h" 65#include "scoped_thread_state_change.h" 66#include "handle_scope-inl.h" 67#include "thread_list.h" 68#include "well_known_classes.h" 69 70namespace art { 71 72namespace gc { 73 74static constexpr size_t kCollectorTransitionStressIterations = 0; 75static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 76static constexpr bool kGCALotMode = false; 77static constexpr size_t kGcAlotInterval = KB; 78// Minimum amount of remaining bytes before a concurrent GC is triggered. 79static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 80static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 81// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 82// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 83// threads (lower pauses, use less memory bandwidth). 84static constexpr double kStickyGcThroughputAdjustment = 1.0; 85// Whether or not we use the free list large object space. 86static constexpr bool kUseFreeListSpaceForLOS = false; 87// Whether or not we compact the zygote in PreZygoteFork. 88static constexpr bool kCompactZygote = kMovingCollector; 89// How many reserve entries are at the end of the allocation stack, these are only needed if the 90// allocation stack overflows. 91static constexpr size_t kAllocationStackReserveSize = 1024; 92// Default mark stack size in bytes. 93static const size_t kDefaultMarkStackSize = 64 * KB; 94// Define space name. 95static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 96static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 97static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 98static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 99 100Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 101 double target_utilization, double foreground_heap_growth_multiplier, 102 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 103 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 104 CollectorType background_collector_type, size_t parallel_gc_threads, 105 size_t conc_gc_threads, bool low_memory_mode, 106 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 107 bool ignore_max_footprint, bool use_tlab, 108 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 109 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 110 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 111 uint64_t min_interval_homogeneous_space_compaction_by_oom) 112 : non_moving_space_(nullptr), 113 rosalloc_space_(nullptr), 114 dlmalloc_space_(nullptr), 115 main_space_(nullptr), 116 collector_type_(kCollectorTypeNone), 117 foreground_collector_type_(foreground_collector_type), 118 background_collector_type_(background_collector_type), 119 desired_collector_type_(foreground_collector_type_), 120 heap_trim_request_lock_(nullptr), 121 last_trim_time_(0), 122 heap_transition_or_trim_target_time_(0), 123 heap_trim_request_pending_(false), 124 parallel_gc_threads_(parallel_gc_threads), 125 conc_gc_threads_(conc_gc_threads), 126 low_memory_mode_(low_memory_mode), 127 long_pause_log_threshold_(long_pause_log_threshold), 128 long_gc_log_threshold_(long_gc_log_threshold), 129 ignore_max_footprint_(ignore_max_footprint), 130 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 131 have_zygote_space_(false), 132 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 133 collector_type_running_(kCollectorTypeNone), 134 last_gc_type_(collector::kGcTypeNone), 135 next_gc_type_(collector::kGcTypePartial), 136 capacity_(capacity), 137 growth_limit_(growth_limit), 138 max_allowed_footprint_(initial_size), 139 native_footprint_gc_watermark_(initial_size), 140 native_footprint_limit_(2 * 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 gc_memory_overhead_(0), 150 verify_missing_card_marks_(false), 151 verify_system_weaks_(false), 152 verify_pre_gc_heap_(verify_pre_gc_heap), 153 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 154 verify_post_gc_heap_(verify_post_gc_heap), 155 verify_mod_union_table_(false), 156 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 157 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 158 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 159 last_gc_time_ns_(NanoTime()), 160 allocation_rate_(0), 161 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 162 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 163 * verification is enabled, we limit the size of allocation stacks to speed up their 164 * searching. 165 */ 166 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 167 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 168 current_allocator_(kAllocatorTypeDlMalloc), 169 current_non_moving_allocator_(kAllocatorTypeNonMoving), 170 bump_pointer_space_(nullptr), 171 temp_space_(nullptr), 172 min_free_(min_free), 173 max_free_(max_free), 174 target_utilization_(target_utilization), 175 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 176 total_wait_time_(0), 177 total_allocation_time_(0), 178 verify_object_mode_(kVerifyObjectModeDisabled), 179 disable_moving_gc_count_(0), 180 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 181 use_tlab_(use_tlab), 182 main_space_backup_(nullptr), 183 min_interval_homogeneous_space_compaction_by_oom_( 184 min_interval_homogeneous_space_compaction_by_oom), 185 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 186 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 187 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 188 LOG(INFO) << "Heap() entering"; 189 } 190 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 191 // entrypoints. 192 if (!Runtime::Current()->IsZygote()) { 193 large_object_threshold_ = kDefaultLargeObjectThreshold; 194 // Background compaction is currently not supported for command line runs. 195 if (background_collector_type_ != foreground_collector_type_) { 196 VLOG(heap) << "Disabling background compaction for non zygote"; 197 background_collector_type_ = foreground_collector_type_; 198 } 199 } 200 ChangeCollector(desired_collector_type_); 201 live_bitmap_.reset(new accounting::HeapBitmap(this)); 202 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 203 // Requested begin for the alloc space, to follow the mapped image and oat files 204 byte* requested_alloc_space_begin = nullptr; 205 if (!image_file_name.empty()) { 206 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 207 image_instruction_set); 208 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 209 AddSpace(image_space); 210 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 211 // isn't going to get in the middle 212 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 213 CHECK_GT(oat_file_end_addr, image_space->End()); 214 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 215 } 216 /* 217 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 218 +- nonmoving space (non_moving_space_capacity)+- 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 220 +-main alloc space / bump space 1 (capacity_) +- 221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 222 +-????????????????????????????????????????????+- 223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 224 +-main alloc space2 / bump space 2 (capacity_)+- 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 226 */ 227 bool support_homogeneous_space_compaction = 228 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 229 use_homogeneous_space_compaction_for_oom; 230 // We may use the same space the main space for the non moving space if we don't need to compact 231 // from the main space. 232 // This is not the case if we support homogeneous compaction or have a moving background 233 // collector type. 234 const bool is_zygote = Runtime::Current()->IsZygote(); 235 bool separate_non_moving_space = is_zygote || 236 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 237 IsMovingGc(background_collector_type_); 238 if (foreground_collector_type == kCollectorTypeGSS) { 239 separate_non_moving_space = false; 240 } 241 std::unique_ptr<MemMap> main_mem_map_1; 242 std::unique_ptr<MemMap> main_mem_map_2; 243 byte* request_begin = requested_alloc_space_begin; 244 if (request_begin != nullptr && separate_non_moving_space) { 245 request_begin += non_moving_space_capacity; 246 } 247 std::string error_str; 248 std::unique_ptr<MemMap> non_moving_space_mem_map; 249 if (separate_non_moving_space) { 250 // Reserve the non moving mem map before the other two since it needs to be at a specific 251 // address. 252 non_moving_space_mem_map.reset( 253 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 254 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 255 CHECK(non_moving_space_mem_map != nullptr) << error_str; 256 } 257 // Attempt to create 2 mem maps at or after the requested begin. 258 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 259 PROT_READ | PROT_WRITE, &error_str)); 260 CHECK(main_mem_map_1.get() != nullptr) << error_str; 261 if (support_homogeneous_space_compaction || 262 background_collector_type_ == kCollectorTypeSS || 263 foreground_collector_type_ == kCollectorTypeSS) { 264 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 265 capacity_, PROT_READ | PROT_WRITE, 266 &error_str)); 267 CHECK(main_mem_map_2.get() != nullptr) << error_str; 268 } 269 // Create the non moving space first so that bitmaps don't take up the address range. 270 if (separate_non_moving_space) { 271 // Non moving space is always dlmalloc since we currently don't have support for multiple 272 // active rosalloc spaces. 273 const size_t size = non_moving_space_mem_map->Size(); 274 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 275 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 276 initial_size, size, size, false); 277 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 278 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 279 << requested_alloc_space_begin; 280 AddSpace(non_moving_space_); 281 } 282 // Create other spaces based on whether or not we have a moving GC. 283 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 284 // Create bump pointer spaces. 285 // We only to create the bump pointer if the foreground collector is a compacting GC. 286 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 287 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 288 main_mem_map_1.release()); 289 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 290 AddSpace(bump_pointer_space_); 291 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 292 main_mem_map_2.release()); 293 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 294 AddSpace(temp_space_); 295 CHECK(separate_non_moving_space); 296 } else { 297 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 298 CHECK(main_space_ != nullptr); 299 AddSpace(main_space_); 300 if (!separate_non_moving_space) { 301 non_moving_space_ = main_space_; 302 CHECK(!non_moving_space_->CanMoveObjects()); 303 } 304 if (foreground_collector_type_ == kCollectorTypeGSS) { 305 CHECK_EQ(foreground_collector_type_, background_collector_type_); 306 // Create bump pointer spaces instead of a backup space. 307 main_mem_map_2.release(); 308 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 309 kGSSBumpPointerSpaceCapacity, nullptr); 310 CHECK(bump_pointer_space_ != nullptr); 311 AddSpace(bump_pointer_space_); 312 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 313 kGSSBumpPointerSpaceCapacity, nullptr); 314 CHECK(temp_space_ != nullptr); 315 AddSpace(temp_space_); 316 } else if (main_mem_map_2.get() != nullptr) { 317 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 318 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 319 growth_limit_, capacity_, name, true)); 320 CHECK(main_space_backup_.get() != nullptr); 321 // Add the space so its accounted for in the heap_begin and heap_end. 322 AddSpace(main_space_backup_.get()); 323 } 324 } 325 CHECK(non_moving_space_ != nullptr); 326 CHECK(!non_moving_space_->CanMoveObjects()); 327 // Allocate the large object space. 328 if (kUseFreeListSpaceForLOS) { 329 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 330 } else { 331 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 332 } 333 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 334 AddSpace(large_object_space_); 335 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 336 CHECK(!continuous_spaces_.empty()); 337 // Relies on the spaces being sorted. 338 byte* heap_begin = continuous_spaces_.front()->Begin(); 339 byte* heap_end = continuous_spaces_.back()->Limit(); 340 size_t heap_capacity = heap_end - heap_begin; 341 // Remove the main backup space since it slows down the GC to have unused extra spaces. 342 if (main_space_backup_.get() != nullptr) { 343 RemoveSpace(main_space_backup_.get()); 344 } 345 // Allocate the card table. 346 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 347 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 348 // Card cache for now since it makes it easier for us to update the references to the copying 349 // spaces. 350 accounting::ModUnionTable* mod_union_table = 351 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 352 GetImageSpace()); 353 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 354 AddModUnionTable(mod_union_table); 355 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 356 accounting::RememberedSet* non_moving_space_rem_set = 357 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 358 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 359 AddRememberedSet(non_moving_space_rem_set); 360 } 361 // TODO: Count objects in the image space here? 362 num_bytes_allocated_.StoreRelaxed(0); 363 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 364 kDefaultMarkStackSize)); 365 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 366 allocation_stack_.reset(accounting::ObjectStack::Create( 367 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 368 live_stack_.reset(accounting::ObjectStack::Create( 369 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 370 // It's still too early to take a lock because there are no threads yet, but we can create locks 371 // now. We don't create it earlier to make it clear that you can't use locks during heap 372 // initialization. 373 gc_complete_lock_ = new Mutex("GC complete lock"); 374 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 375 *gc_complete_lock_)); 376 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 377 last_gc_size_ = GetBytesAllocated(); 378 if (ignore_max_footprint_) { 379 SetIdealFootprint(std::numeric_limits<size_t>::max()); 380 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 381 } 382 CHECK_NE(max_allowed_footprint_, 0U); 383 // Create our garbage collectors. 384 for (size_t i = 0; i < 2; ++i) { 385 const bool concurrent = i != 0; 386 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 387 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 388 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 389 } 390 if (kMovingCollector) { 391 // TODO: Clean this up. 392 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 393 semi_space_collector_ = new collector::SemiSpace(this, generational, 394 generational ? "generational" : ""); 395 garbage_collectors_.push_back(semi_space_collector_); 396 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 397 garbage_collectors_.push_back(concurrent_copying_collector_); 398 mark_compact_collector_ = new collector::MarkCompact(this); 399 garbage_collectors_.push_back(mark_compact_collector_); 400 } 401 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr) { 402 // Check that there's no gap between the image space and the non moving space so that the 403 // immune region won't break (eg. due to a large object allocated in the gap). 404 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 405 non_moving_space_->GetMemMap()); 406 if (!no_gap) { 407 MemMap::DumpMaps(LOG(ERROR)); 408 LOG(FATAL) << "There's a gap between the image space and the main space"; 409 } 410 } 411 if (running_on_valgrind_) { 412 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 413 } 414 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 415 LOG(INFO) << "Heap() exiting"; 416 } 417} 418 419MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 420 int prot_flags, std::string* out_error_str) { 421 while (true) { 422 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 423 PROT_READ | PROT_WRITE, true, out_error_str); 424 if (map != nullptr || request_begin == nullptr) { 425 return map; 426 } 427 // Retry a second time with no specified request begin. 428 request_begin = nullptr; 429 } 430 return nullptr; 431} 432 433space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 434 size_t growth_limit, size_t capacity, 435 const char* name, bool can_move_objects) { 436 space::MallocSpace* malloc_space = nullptr; 437 if (kUseRosAlloc) { 438 // Create rosalloc space. 439 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 440 initial_size, growth_limit, capacity, 441 low_memory_mode_, can_move_objects); 442 } else { 443 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 444 initial_size, growth_limit, capacity, 445 can_move_objects); 446 } 447 if (collector::SemiSpace::kUseRememberedSet) { 448 accounting::RememberedSet* rem_set = 449 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 450 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 451 AddRememberedSet(rem_set); 452 } 453 CHECK(malloc_space != nullptr) << "Failed to create " << name; 454 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 455 return malloc_space; 456} 457 458void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 459 size_t capacity) { 460 // Is background compaction is enabled? 461 bool can_move_objects = IsMovingGc(background_collector_type_) != 462 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 463 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 464 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 465 // from the main space to the zygote space. If background compaction is enabled, always pass in 466 // that we can move objets. 467 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 468 // After the zygote we want this to be false if we don't have background compaction enabled so 469 // that getting primitive array elements is faster. 470 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 471 can_move_objects = !have_zygote_space_ && foreground_collector_type_ != kCollectorTypeGSS; 472 } 473 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 474 RemoveRememberedSet(main_space_); 475 } 476 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 477 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 478 can_move_objects); 479 SetSpaceAsDefault(main_space_); 480 VLOG(heap) << "Created main space " << main_space_; 481} 482 483void Heap::ChangeAllocator(AllocatorType allocator) { 484 if (current_allocator_ != allocator) { 485 // These two allocators are only used internally and don't have any entrypoints. 486 CHECK_NE(allocator, kAllocatorTypeLOS); 487 CHECK_NE(allocator, kAllocatorTypeNonMoving); 488 current_allocator_ = allocator; 489 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 490 SetQuickAllocEntryPointsAllocator(current_allocator_); 491 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 492 } 493} 494 495void Heap::DisableMovingGc() { 496 if (IsMovingGc(foreground_collector_type_)) { 497 foreground_collector_type_ = kCollectorTypeCMS; 498 } 499 if (IsMovingGc(background_collector_type_)) { 500 background_collector_type_ = foreground_collector_type_; 501 } 502 TransitionCollector(foreground_collector_type_); 503 ThreadList* tl = Runtime::Current()->GetThreadList(); 504 Thread* self = Thread::Current(); 505 ScopedThreadStateChange tsc(self, kSuspended); 506 tl->SuspendAll(); 507 // Something may have caused the transition to fail. 508 if (!IsMovingGc(foreground_collector_type_) && non_moving_space_ != main_space_) { 509 CHECK(main_space_ != nullptr); 510 // The allocation stack may have non movable objects in it. We need to flush it since the GC 511 // can't only handle marking allocation stack objects of one non moving space and one main 512 // space. 513 { 514 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 515 FlushAllocStack(); 516 } 517 main_space_->DisableMovingObjects(); 518 non_moving_space_ = main_space_; 519 CHECK(!non_moving_space_->CanMoveObjects()); 520 } 521 tl->ResumeAll(); 522} 523 524std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 525 if (!IsValidContinuousSpaceObjectAddress(klass)) { 526 return StringPrintf("<non heap address klass %p>", klass); 527 } 528 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 529 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 530 std::string result("["); 531 result += SafeGetClassDescriptor(component_type); 532 return result; 533 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 534 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 535 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 536 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 537 } else { 538 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 539 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 540 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 541 } 542 const DexFile* dex_file = dex_cache->GetDexFile(); 543 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 544 if (class_def_idx == DexFile::kDexNoIndex16) { 545 return "<class def not found>"; 546 } 547 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 548 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 549 return dex_file->GetTypeDescriptor(type_id); 550 } 551} 552 553std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 554 if (obj == nullptr) { 555 return "null"; 556 } 557 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 558 if (klass == nullptr) { 559 return "(class=null)"; 560 } 561 std::string result(SafeGetClassDescriptor(klass)); 562 if (obj->IsClass()) { 563 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 564 } 565 return result; 566} 567 568void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 569 if (obj == nullptr) { 570 stream << "(obj=null)"; 571 return; 572 } 573 if (IsAligned<kObjectAlignment>(obj)) { 574 space::Space* space = nullptr; 575 // Don't use find space since it only finds spaces which actually contain objects instead of 576 // spaces which may contain objects (e.g. cleared bump pointer spaces). 577 for (const auto& cur_space : continuous_spaces_) { 578 if (cur_space->HasAddress(obj)) { 579 space = cur_space; 580 break; 581 } 582 } 583 // Unprotect all the spaces. 584 for (const auto& space : continuous_spaces_) { 585 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 586 } 587 stream << "Object " << obj; 588 if (space != nullptr) { 589 stream << " in space " << *space; 590 } 591 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 592 stream << "\nclass=" << klass; 593 if (klass != nullptr) { 594 stream << " type= " << SafePrettyTypeOf(obj); 595 } 596 // Re-protect the address we faulted on. 597 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 598 } 599} 600 601bool Heap::IsCompilingBoot() const { 602 for (const auto& space : continuous_spaces_) { 603 if (space->IsImageSpace() || space->IsZygoteSpace()) { 604 return false; 605 } 606 } 607 return true; 608} 609 610bool Heap::HasImageSpace() const { 611 for (const auto& space : continuous_spaces_) { 612 if (space->IsImageSpace()) { 613 return true; 614 } 615 } 616 return false; 617} 618 619void Heap::IncrementDisableMovingGC(Thread* self) { 620 // Need to do this holding the lock to prevent races where the GC is about to run / running when 621 // we attempt to disable it. 622 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 623 MutexLock mu(self, *gc_complete_lock_); 624 ++disable_moving_gc_count_; 625 if (IsMovingGc(collector_type_running_)) { 626 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 627 } 628} 629 630void Heap::DecrementDisableMovingGC(Thread* self) { 631 MutexLock mu(self, *gc_complete_lock_); 632 CHECK_GE(disable_moving_gc_count_, 0U); 633 --disable_moving_gc_count_; 634} 635 636void Heap::UpdateProcessState(ProcessState process_state) { 637 if (process_state_ != process_state) { 638 process_state_ = process_state; 639 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 640 // Start at index 1 to avoid "is always false" warning. 641 // Have iteration 1 always transition the collector. 642 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 643 ? foreground_collector_type_ : background_collector_type_); 644 usleep(kCollectorTransitionStressWait); 645 } 646 if (process_state_ == kProcessStateJankPerceptible) { 647 // Transition back to foreground right away to prevent jank. 648 RequestCollectorTransition(foreground_collector_type_, 0); 649 } else { 650 // Don't delay for debug builds since we may want to stress test the GC. 651 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 652 // special handling which does a homogenous space compaction once but then doesn't transition 653 // the collector. 654 RequestCollectorTransition(background_collector_type_, 655 kIsDebugBuild ? 0 : kCollectorTransitionWait); 656 } 657 } 658} 659 660void Heap::CreateThreadPool() { 661 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 662 if (num_threads != 0) { 663 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 664 } 665} 666 667void Heap::VisitObjects(ObjectCallback callback, void* arg) { 668 Thread* self = Thread::Current(); 669 // GCs can move objects, so don't allow this. 670 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 671 if (bump_pointer_space_ != nullptr) { 672 // Visit objects in bump pointer space. 673 bump_pointer_space_->Walk(callback, arg); 674 } 675 // TODO: Switch to standard begin and end to use ranged a based loop. 676 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 677 it < end; ++it) { 678 mirror::Object* obj = *it; 679 if (obj != nullptr && obj->GetClass() != nullptr) { 680 // Avoid the race condition caused by the object not yet being written into the allocation 681 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 682 // there can be nulls on the allocation stack. 683 callback(obj, arg); 684 } 685 } 686 GetLiveBitmap()->Walk(callback, arg); 687 self->EndAssertNoThreadSuspension(old_cause); 688} 689 690void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 691 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 692 space::ContinuousSpace* space2 = non_moving_space_; 693 // TODO: Generalize this to n bitmaps? 694 CHECK(space1 != nullptr); 695 CHECK(space2 != nullptr); 696 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 697 large_object_space_->GetLiveBitmap(), stack); 698} 699 700void Heap::DeleteThreadPool() { 701 thread_pool_.reset(nullptr); 702} 703 704void Heap::AddSpace(space::Space* space) { 705 CHECK(space != nullptr); 706 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 707 if (space->IsContinuousSpace()) { 708 DCHECK(!space->IsDiscontinuousSpace()); 709 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 710 // Continuous spaces don't necessarily have bitmaps. 711 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 712 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 713 if (live_bitmap != nullptr) { 714 CHECK(mark_bitmap != nullptr); 715 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 716 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 717 } 718 continuous_spaces_.push_back(continuous_space); 719 // Ensure that spaces remain sorted in increasing order of start address. 720 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 721 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 722 return a->Begin() < b->Begin(); 723 }); 724 } else { 725 CHECK(space->IsDiscontinuousSpace()); 726 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 727 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 728 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 729 discontinuous_spaces_.push_back(discontinuous_space); 730 } 731 if (space->IsAllocSpace()) { 732 alloc_spaces_.push_back(space->AsAllocSpace()); 733 } 734} 735 736void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 737 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 738 if (continuous_space->IsDlMallocSpace()) { 739 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 740 } else if (continuous_space->IsRosAllocSpace()) { 741 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 742 } 743} 744 745void Heap::RemoveSpace(space::Space* space) { 746 DCHECK(space != nullptr); 747 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 748 if (space->IsContinuousSpace()) { 749 DCHECK(!space->IsDiscontinuousSpace()); 750 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 751 // Continuous spaces don't necessarily have bitmaps. 752 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 753 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 754 if (live_bitmap != nullptr) { 755 DCHECK(mark_bitmap != nullptr); 756 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 757 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 758 } 759 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 760 DCHECK(it != continuous_spaces_.end()); 761 continuous_spaces_.erase(it); 762 } else { 763 DCHECK(space->IsDiscontinuousSpace()); 764 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 765 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 766 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 767 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 768 discontinuous_space); 769 DCHECK(it != discontinuous_spaces_.end()); 770 discontinuous_spaces_.erase(it); 771 } 772 if (space->IsAllocSpace()) { 773 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 774 DCHECK(it != alloc_spaces_.end()); 775 alloc_spaces_.erase(it); 776 } 777} 778 779void Heap::RegisterGCAllocation(size_t bytes) { 780 gc_memory_overhead_.FetchAndAddSequentiallyConsistent(bytes); 781} 782 783void Heap::RegisterGCDeAllocation(size_t bytes) { 784 gc_memory_overhead_.FetchAndSubSequentiallyConsistent(bytes); 785} 786 787void Heap::DumpGcPerformanceInfo(std::ostream& os) { 788 // Dump cumulative timings. 789 os << "Dumping cumulative Gc timings\n"; 790 uint64_t total_duration = 0; 791 // Dump cumulative loggers for each GC type. 792 uint64_t total_paused_time = 0; 793 for (auto& collector : garbage_collectors_) { 794 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 795 const size_t iterations = logger.GetIterations(); 796 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 797 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 798 os << ConstDumpable<CumulativeLogger>(logger); 799 const uint64_t total_ns = logger.GetTotalNs(); 800 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 801 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 802 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 803 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 804 Histogram<uint64_t>::CumulativeData cumulative_data; 805 pause_histogram.CreateHistogram(&cumulative_data); 806 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 807 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 808 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 809 << collector->GetName() << " freed: " << freed_objects 810 << " objects with total size " << PrettySize(freed_bytes) << "\n" 811 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 812 << PrettySize(freed_bytes / seconds) << "/s\n"; 813 total_duration += total_ns; 814 total_paused_time += total_pause_ns; 815 } 816 collector->ResetMeasurements(); 817 } 818 uint64_t allocation_time = 819 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 820 if (total_duration != 0) { 821 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 822 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 823 os << "Mean GC size throughput: " 824 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 825 os << "Mean GC object throughput: " 826 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 827 } 828 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 829 os << "Total number of allocations " << total_objects_allocated << "\n"; 830 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 831 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 832 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 833 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 834 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 835 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 836 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 837 if (kMeasureAllocationTime) { 838 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 839 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 840 << "\n"; 841 } 842 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 843 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 844 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_.LoadRelaxed(); 845 BaseMutex::DumpAll(os); 846} 847 848Heap::~Heap() { 849 VLOG(heap) << "Starting ~Heap()"; 850 STLDeleteElements(&garbage_collectors_); 851 // If we don't reset then the mark stack complains in its destructor. 852 allocation_stack_->Reset(); 853 live_stack_->Reset(); 854 STLDeleteValues(&mod_union_tables_); 855 STLDeleteValues(&remembered_sets_); 856 STLDeleteElements(&continuous_spaces_); 857 STLDeleteElements(&discontinuous_spaces_); 858 delete gc_complete_lock_; 859 delete heap_trim_request_lock_; 860 VLOG(heap) << "Finished ~Heap()"; 861} 862 863space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 864 bool fail_ok) const { 865 for (const auto& space : continuous_spaces_) { 866 if (space->Contains(obj)) { 867 return space; 868 } 869 } 870 if (!fail_ok) { 871 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 872 } 873 return NULL; 874} 875 876space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 877 bool fail_ok) const { 878 for (const auto& space : discontinuous_spaces_) { 879 if (space->Contains(obj)) { 880 return space; 881 } 882 } 883 if (!fail_ok) { 884 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 885 } 886 return NULL; 887} 888 889space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 890 space::Space* result = FindContinuousSpaceFromObject(obj, true); 891 if (result != NULL) { 892 return result; 893 } 894 return FindDiscontinuousSpaceFromObject(obj, true); 895} 896 897space::ImageSpace* Heap::GetImageSpace() const { 898 for (const auto& space : continuous_spaces_) { 899 if (space->IsImageSpace()) { 900 return space->AsImageSpace(); 901 } 902 } 903 return NULL; 904} 905 906void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 907 std::ostringstream oss; 908 size_t total_bytes_free = GetFreeMemory(); 909 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 910 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 911 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 912 if (total_bytes_free >= byte_count) { 913 space::AllocSpace* space = nullptr; 914 if (allocator_type == kAllocatorTypeNonMoving) { 915 space = non_moving_space_; 916 } else if (allocator_type == kAllocatorTypeRosAlloc || 917 allocator_type == kAllocatorTypeDlMalloc) { 918 space = main_space_; 919 } else if (allocator_type == kAllocatorTypeBumpPointer || 920 allocator_type == kAllocatorTypeTLAB) { 921 space = bump_pointer_space_; 922 } 923 if (space != nullptr) { 924 space->LogFragmentationAllocFailure(oss, byte_count); 925 } 926 } 927 self->ThrowOutOfMemoryError(oss.str().c_str()); 928} 929 930void Heap::DoPendingTransitionOrTrim() { 931 Thread* self = Thread::Current(); 932 CollectorType desired_collector_type; 933 // Wait until we reach the desired transition time. 934 while (true) { 935 uint64_t wait_time; 936 { 937 MutexLock mu(self, *heap_trim_request_lock_); 938 desired_collector_type = desired_collector_type_; 939 uint64_t current_time = NanoTime(); 940 if (current_time >= heap_transition_or_trim_target_time_) { 941 break; 942 } 943 wait_time = heap_transition_or_trim_target_time_ - current_time; 944 } 945 ScopedThreadStateChange tsc(self, kSleeping); 946 usleep(wait_time / 1000); // Usleep takes microseconds. 947 } 948 // Launch homogeneous space compaction if it is desired. 949 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 950 if (!CareAboutPauseTimes()) { 951 PerformHomogeneousSpaceCompact(); 952 } 953 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 954 desired_collector_type = collector_type_; 955 return; 956 } 957 // Transition the collector if the desired collector type is not the same as the current 958 // collector type. 959 TransitionCollector(desired_collector_type); 960 if (!CareAboutPauseTimes()) { 961 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 962 // about pauses. 963 Runtime* runtime = Runtime::Current(); 964 runtime->GetThreadList()->SuspendAll(); 965 uint64_t start_time = NanoTime(); 966 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 967 VLOG(heap) << "Deflating " << count << " monitors took " 968 << PrettyDuration(NanoTime() - start_time); 969 runtime->GetThreadList()->ResumeAll(); 970 } 971 // Do a heap trim if it is needed. 972 Trim(); 973} 974 975void Heap::Trim() { 976 Thread* self = Thread::Current(); 977 { 978 MutexLock mu(self, *heap_trim_request_lock_); 979 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 980 return; 981 } 982 last_trim_time_ = NanoTime(); 983 heap_trim_request_pending_ = false; 984 } 985 { 986 // Need to do this before acquiring the locks since we don't want to get suspended while 987 // holding any locks. 988 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 989 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 990 // trimming. 991 MutexLock mu(self, *gc_complete_lock_); 992 // Ensure there is only one GC at a time. 993 WaitForGcToCompleteLocked(kGcCauseTrim, self); 994 collector_type_running_ = kCollectorTypeHeapTrim; 995 } 996 uint64_t start_ns = NanoTime(); 997 // Trim the managed spaces. 998 uint64_t total_alloc_space_allocated = 0; 999 uint64_t total_alloc_space_size = 0; 1000 uint64_t managed_reclaimed = 0; 1001 for (const auto& space : continuous_spaces_) { 1002 if (space->IsMallocSpace()) { 1003 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 1004 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 1005 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 1006 // for a long period of time. 1007 managed_reclaimed += malloc_space->Trim(); 1008 } 1009 total_alloc_space_size += malloc_space->Size(); 1010 } 1011 } 1012 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 1013 if (bump_pointer_space_ != nullptr) { 1014 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1015 } 1016 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1017 static_cast<float>(total_alloc_space_size); 1018 uint64_t gc_heap_end_ns = NanoTime(); 1019 // We never move things in the native heap, so we can finish the GC at this point. 1020 FinishGC(self, collector::kGcTypeNone); 1021 size_t native_reclaimed = 0; 1022 // Only trim the native heap if we don't care about pauses. 1023 if (!CareAboutPauseTimes()) { 1024#if defined(USE_DLMALLOC) 1025 // Trim the native heap. 1026 dlmalloc_trim(0); 1027 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1028#elif defined(USE_JEMALLOC) 1029 // Jemalloc does it's own internal trimming. 1030#else 1031 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1032#endif 1033 } 1034 uint64_t end_ns = NanoTime(); 1035 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1036 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1037 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1038 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1039 << "%."; 1040} 1041 1042bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1043 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1044 // taking the lock. 1045 if (obj == nullptr) { 1046 return true; 1047 } 1048 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1049} 1050 1051bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1052 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1053} 1054 1055bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1056 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1057 return false; 1058 } 1059 for (const auto& space : continuous_spaces_) { 1060 if (space->HasAddress(obj)) { 1061 return true; 1062 } 1063 } 1064 return false; 1065} 1066 1067bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1068 bool search_live_stack, bool sorted) { 1069 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1070 return false; 1071 } 1072 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1073 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1074 if (obj == klass) { 1075 // This case happens for java.lang.Class. 1076 return true; 1077 } 1078 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1079 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1080 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1081 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1082 return temp_space_->Contains(obj); 1083 } 1084 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1085 space::DiscontinuousSpace* d_space = nullptr; 1086 if (c_space != nullptr) { 1087 if (c_space->GetLiveBitmap()->Test(obj)) { 1088 return true; 1089 } 1090 } else { 1091 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1092 if (d_space != nullptr) { 1093 if (d_space->GetLiveBitmap()->Test(obj)) { 1094 return true; 1095 } 1096 } 1097 } 1098 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1099 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1100 if (i > 0) { 1101 NanoSleep(MsToNs(10)); 1102 } 1103 if (search_allocation_stack) { 1104 if (sorted) { 1105 if (allocation_stack_->ContainsSorted(obj)) { 1106 return true; 1107 } 1108 } else if (allocation_stack_->Contains(obj)) { 1109 return true; 1110 } 1111 } 1112 1113 if (search_live_stack) { 1114 if (sorted) { 1115 if (live_stack_->ContainsSorted(obj)) { 1116 return true; 1117 } 1118 } else if (live_stack_->Contains(obj)) { 1119 return true; 1120 } 1121 } 1122 } 1123 // We need to check the bitmaps again since there is a race where we mark something as live and 1124 // then clear the stack containing it. 1125 if (c_space != nullptr) { 1126 if (c_space->GetLiveBitmap()->Test(obj)) { 1127 return true; 1128 } 1129 } else { 1130 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1131 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1132 return true; 1133 } 1134 } 1135 return false; 1136} 1137 1138std::string Heap::DumpSpaces() const { 1139 std::ostringstream oss; 1140 DumpSpaces(oss); 1141 return oss.str(); 1142} 1143 1144void Heap::DumpSpaces(std::ostream& stream) const { 1145 for (const auto& space : continuous_spaces_) { 1146 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1147 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1148 stream << space << " " << *space << "\n"; 1149 if (live_bitmap != nullptr) { 1150 stream << live_bitmap << " " << *live_bitmap << "\n"; 1151 } 1152 if (mark_bitmap != nullptr) { 1153 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1154 } 1155 } 1156 for (const auto& space : discontinuous_spaces_) { 1157 stream << space << " " << *space << "\n"; 1158 } 1159} 1160 1161void Heap::VerifyObjectBody(mirror::Object* obj) { 1162 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1163 return; 1164 } 1165 1166 // Ignore early dawn of the universe verifications. 1167 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1168 return; 1169 } 1170 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1171 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1172 CHECK(c != nullptr) << "Null class in object " << obj; 1173 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1174 CHECK(VerifyClassClass(c)); 1175 1176 if (verify_object_mode_ > kVerifyObjectModeFast) { 1177 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1178 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1179 } 1180} 1181 1182void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1183 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1184} 1185 1186void Heap::VerifyHeap() { 1187 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1188 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1189} 1190 1191void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1192 // Use signed comparison since freed bytes can be negative when background compaction foreground 1193 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1194 // free list backed space typically increasing memory footprint due to padding and binning. 1195 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1196 // Note: This relies on 2s complement for handling negative freed_bytes. 1197 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1198 if (Runtime::Current()->HasStatsEnabled()) { 1199 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1200 thread_stats->freed_objects += freed_objects; 1201 thread_stats->freed_bytes += freed_bytes; 1202 // TODO: Do this concurrently. 1203 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1204 global_stats->freed_objects += freed_objects; 1205 global_stats->freed_bytes += freed_bytes; 1206 } 1207} 1208 1209space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1210 for (const auto& space : continuous_spaces_) { 1211 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1212 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1213 return space->AsContinuousSpace()->AsRosAllocSpace(); 1214 } 1215 } 1216 } 1217 return nullptr; 1218} 1219 1220mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1221 size_t alloc_size, size_t* bytes_allocated, 1222 size_t* usable_size, 1223 mirror::Class** klass) { 1224 bool was_default_allocator = allocator == GetCurrentAllocator(); 1225 DCHECK(klass != nullptr); 1226 StackHandleScope<1> hs(self); 1227 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1228 klass = nullptr; // Invalidate for safety. 1229 // The allocation failed. If the GC is running, block until it completes, and then retry the 1230 // allocation. 1231 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1232 if (last_gc != collector::kGcTypeNone) { 1233 // If we were the default allocator but the allocator changed while we were suspended, 1234 // abort the allocation. 1235 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1236 return nullptr; 1237 } 1238 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1239 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1240 usable_size); 1241 if (ptr != nullptr) { 1242 return ptr; 1243 } 1244 } 1245 1246 collector::GcType tried_type = next_gc_type_; 1247 const bool gc_ran = 1248 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1249 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1250 return nullptr; 1251 } 1252 if (gc_ran) { 1253 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1254 usable_size); 1255 if (ptr != nullptr) { 1256 return ptr; 1257 } 1258 } 1259 1260 // Loop through our different Gc types and try to Gc until we get enough free memory. 1261 for (collector::GcType gc_type : gc_plan_) { 1262 if (gc_type == tried_type) { 1263 continue; 1264 } 1265 // Attempt to run the collector, if we succeed, re-try the allocation. 1266 const bool gc_ran = 1267 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1268 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1269 return nullptr; 1270 } 1271 if (gc_ran) { 1272 // Did we free sufficient memory for the allocation to succeed? 1273 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1274 usable_size); 1275 if (ptr != nullptr) { 1276 return ptr; 1277 } 1278 } 1279 } 1280 // Allocations have failed after GCs; this is an exceptional state. 1281 // Try harder, growing the heap if necessary. 1282 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1283 usable_size); 1284 if (ptr != nullptr) { 1285 return ptr; 1286 } 1287 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1288 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1289 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1290 // OOME. 1291 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1292 << " allocation"; 1293 // TODO: Run finalization, but this may cause more allocations to occur. 1294 // We don't need a WaitForGcToComplete here either. 1295 DCHECK(!gc_plan_.empty()); 1296 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1297 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1298 return nullptr; 1299 } 1300 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1301 if (ptr == nullptr) { 1302 const uint64_t current_time = NanoTime(); 1303 switch (allocator) { 1304 case kAllocatorTypeRosAlloc: 1305 // Fall-through. 1306 case kAllocatorTypeDlMalloc: { 1307 if (use_homogeneous_space_compaction_for_oom_ && 1308 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1309 min_interval_homogeneous_space_compaction_by_oom_) { 1310 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1311 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1312 switch (result) { 1313 case HomogeneousSpaceCompactResult::kSuccess: 1314 // If the allocation succeeded, we delayed an oom. 1315 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1316 usable_size); 1317 if (ptr != nullptr) { 1318 count_delayed_oom_++; 1319 } 1320 break; 1321 case HomogeneousSpaceCompactResult::kErrorReject: 1322 // Reject due to disabled moving GC. 1323 break; 1324 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1325 // Throw OOM by default. 1326 break; 1327 default: { 1328 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1329 << static_cast<size_t>(result); 1330 } 1331 } 1332 // Always print that we ran homogeneous space compation since this can cause jank. 1333 VLOG(heap) << "Ran heap homogeneous space compaction, " 1334 << " requested defragmentation " 1335 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1336 << " performed defragmentation " 1337 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1338 << " ignored homogeneous space compaction " 1339 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1340 << " delayed count = " 1341 << count_delayed_oom_.LoadSequentiallyConsistent(); 1342 } 1343 break; 1344 } 1345 case kAllocatorTypeNonMoving: { 1346 // Try to transition the heap if the allocation failure was due to the space being full. 1347 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1348 // If we aren't out of memory then the OOM was probably from the non moving space being 1349 // full. Attempt to disable compaction and turn the main space into a non moving space. 1350 DisableMovingGc(); 1351 // If we are still a moving GC then something must have caused the transition to fail. 1352 if (IsMovingGc(collector_type_)) { 1353 MutexLock mu(self, *gc_complete_lock_); 1354 // If we couldn't disable moving GC, just throw OOME and return null. 1355 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1356 << disable_moving_gc_count_; 1357 } else { 1358 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1359 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1360 usable_size); 1361 } 1362 } 1363 break; 1364 } 1365 default: { 1366 // Do nothing for others allocators. 1367 } 1368 } 1369 } 1370 // If the allocation hasn't succeeded by this point, throw an OOM error. 1371 if (ptr == nullptr) { 1372 ThrowOutOfMemoryError(self, alloc_size, allocator); 1373 } 1374 return ptr; 1375} 1376 1377void Heap::SetTargetHeapUtilization(float target) { 1378 DCHECK_GT(target, 0.0f); // asserted in Java code 1379 DCHECK_LT(target, 1.0f); 1380 target_utilization_ = target; 1381} 1382 1383size_t Heap::GetObjectsAllocated() const { 1384 size_t total = 0; 1385 for (space::AllocSpace* space : alloc_spaces_) { 1386 total += space->GetObjectsAllocated(); 1387 } 1388 return total; 1389} 1390 1391uint64_t Heap::GetObjectsAllocatedEver() const { 1392 return GetObjectsFreedEver() + GetObjectsAllocated(); 1393} 1394 1395uint64_t Heap::GetBytesAllocatedEver() const { 1396 return GetBytesFreedEver() + GetBytesAllocated(); 1397} 1398 1399class InstanceCounter { 1400 public: 1401 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1402 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1403 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1404 } 1405 static void Callback(mirror::Object* obj, void* arg) 1406 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1407 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1408 mirror::Class* instance_class = obj->GetClass(); 1409 CHECK(instance_class != nullptr); 1410 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1411 if (instance_counter->use_is_assignable_from_) { 1412 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1413 ++instance_counter->counts_[i]; 1414 } 1415 } else if (instance_class == instance_counter->classes_[i]) { 1416 ++instance_counter->counts_[i]; 1417 } 1418 } 1419 } 1420 1421 private: 1422 const std::vector<mirror::Class*>& classes_; 1423 bool use_is_assignable_from_; 1424 uint64_t* const counts_; 1425 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1426}; 1427 1428void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1429 uint64_t* counts) { 1430 // Can't do any GC in this function since this may move classes. 1431 Thread* self = Thread::Current(); 1432 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1433 InstanceCounter counter(classes, use_is_assignable_from, counts); 1434 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1435 VisitObjects(InstanceCounter::Callback, &counter); 1436 self->EndAssertNoThreadSuspension(old_cause); 1437} 1438 1439class InstanceCollector { 1440 public: 1441 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1442 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1443 : class_(c), max_count_(max_count), instances_(instances) { 1444 } 1445 static void Callback(mirror::Object* obj, void* arg) 1446 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1447 DCHECK(arg != nullptr); 1448 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1449 mirror::Class* instance_class = obj->GetClass(); 1450 if (instance_class == instance_collector->class_) { 1451 if (instance_collector->max_count_ == 0 || 1452 instance_collector->instances_.size() < instance_collector->max_count_) { 1453 instance_collector->instances_.push_back(obj); 1454 } 1455 } 1456 } 1457 1458 private: 1459 mirror::Class* class_; 1460 uint32_t max_count_; 1461 std::vector<mirror::Object*>& instances_; 1462 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1463}; 1464 1465void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1466 std::vector<mirror::Object*>& instances) { 1467 // Can't do any GC in this function since this may move classes. 1468 Thread* self = Thread::Current(); 1469 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1470 InstanceCollector collector(c, max_count, instances); 1471 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1472 VisitObjects(&InstanceCollector::Callback, &collector); 1473 self->EndAssertNoThreadSuspension(old_cause); 1474} 1475 1476class ReferringObjectsFinder { 1477 public: 1478 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1479 std::vector<mirror::Object*>& referring_objects) 1480 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1481 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1482 } 1483 1484 static void Callback(mirror::Object* obj, void* arg) 1485 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1486 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1487 } 1488 1489 // For bitmap Visit. 1490 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1491 // annotalysis on visitors. 1492 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1493 o->VisitReferences<true>(*this, VoidFunctor()); 1494 } 1495 1496 // For Object::VisitReferences. 1497 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1498 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1499 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1500 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1501 referring_objects_.push_back(obj); 1502 } 1503 } 1504 1505 private: 1506 mirror::Object* object_; 1507 uint32_t max_count_; 1508 std::vector<mirror::Object*>& referring_objects_; 1509 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1510}; 1511 1512void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1513 std::vector<mirror::Object*>& referring_objects) { 1514 // Can't do any GC in this function since this may move the object o. 1515 Thread* self = Thread::Current(); 1516 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1517 ReferringObjectsFinder finder(o, max_count, referring_objects); 1518 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1519 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1520 self->EndAssertNoThreadSuspension(old_cause); 1521} 1522 1523void Heap::CollectGarbage(bool clear_soft_references) { 1524 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1525 // last GC will not have necessarily been cleared. 1526 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1527} 1528 1529HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1530 Thread* self = Thread::Current(); 1531 // Inc requested homogeneous space compaction. 1532 count_requested_homogeneous_space_compaction_++; 1533 // Store performed homogeneous space compaction at a new request arrival. 1534 ThreadList* tl = Runtime::Current()->GetThreadList(); 1535 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1536 Locks::mutator_lock_->AssertNotHeld(self); 1537 { 1538 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1539 MutexLock mu(self, *gc_complete_lock_); 1540 // Ensure there is only one GC at a time. 1541 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1542 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1543 // is non zero. 1544 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1545 // exit. 1546 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1547 !main_space_->CanMoveObjects()) { 1548 return HomogeneousSpaceCompactResult::kErrorReject; 1549 } 1550 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1551 } 1552 if (Runtime::Current()->IsShuttingDown(self)) { 1553 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1554 // cause objects to get finalized. 1555 FinishGC(self, collector::kGcTypeNone); 1556 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1557 } 1558 // Suspend all threads. 1559 tl->SuspendAll(); 1560 uint64_t start_time = NanoTime(); 1561 // Launch compaction. 1562 space::MallocSpace* to_space = main_space_backup_.release(); 1563 space::MallocSpace* from_space = main_space_; 1564 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1565 const uint64_t space_size_before_compaction = from_space->Size(); 1566 AddSpace(to_space); 1567 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1568 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1569 from_space->GetMemMap()->Protect(PROT_READ); 1570 const uint64_t space_size_after_compaction = to_space->Size(); 1571 main_space_ = to_space; 1572 main_space_backup_.reset(from_space); 1573 RemoveSpace(from_space); 1574 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1575 // Update performed homogeneous space compaction count. 1576 count_performed_homogeneous_space_compaction_++; 1577 // Print statics log and resume all threads. 1578 uint64_t duration = NanoTime() - start_time; 1579 VLOG(gc) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1580 << PrettySize(space_size_before_compaction) << " -> " 1581 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1582 << std::fixed << static_cast<double>(space_size_after_compaction) / 1583 static_cast<double>(space_size_before_compaction); 1584 tl->ResumeAll(); 1585 // Finish GC. 1586 reference_processor_.EnqueueClearedReferences(self); 1587 GrowForUtilization(semi_space_collector_); 1588 FinishGC(self, collector::kGcTypeFull); 1589 return HomogeneousSpaceCompactResult::kSuccess; 1590} 1591 1592 1593void Heap::TransitionCollector(CollectorType collector_type) { 1594 if (collector_type == collector_type_) { 1595 return; 1596 } 1597 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1598 << " -> " << static_cast<int>(collector_type); 1599 uint64_t start_time = NanoTime(); 1600 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1601 Runtime* const runtime = Runtime::Current(); 1602 ThreadList* const tl = runtime->GetThreadList(); 1603 Thread* const self = Thread::Current(); 1604 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1605 Locks::mutator_lock_->AssertNotHeld(self); 1606 // Currently we only need a heap transition if we switch from a moving collector to a non moving 1607 // one, or visa versa. 1608 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1609 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1610 // compacting_gc_disable_count_, this should rarely occurs). 1611 for (;;) { 1612 { 1613 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1614 MutexLock mu(self, *gc_complete_lock_); 1615 // Ensure there is only one GC at a time. 1616 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1617 // If someone else beat us to it and changed the collector before we could, exit. 1618 // This is safe to do before the suspend all since we set the collector_type_running_ before 1619 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1620 // then it would get blocked on WaitForGcToCompleteLocked. 1621 if (collector_type == collector_type_) { 1622 return; 1623 } 1624 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1625 if (!copying_transition || disable_moving_gc_count_ == 0) { 1626 // TODO: Not hard code in semi-space collector? 1627 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1628 break; 1629 } 1630 } 1631 usleep(1000); 1632 } 1633 if (runtime->IsShuttingDown(self)) { 1634 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1635 // cause objects to get finalized. 1636 FinishGC(self, collector::kGcTypeNone); 1637 return; 1638 } 1639 tl->SuspendAll(); 1640 switch (collector_type) { 1641 case kCollectorTypeSS: { 1642 if (!IsMovingGc(collector_type_)) { 1643 // Create the bump pointer space from the backup space. 1644 CHECK(main_space_backup_ != nullptr); 1645 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1646 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1647 // pointer space last transition it will be protected. 1648 CHECK(mem_map != nullptr); 1649 mem_map->Protect(PROT_READ | PROT_WRITE); 1650 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1651 mem_map.release()); 1652 AddSpace(bump_pointer_space_); 1653 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1654 // Use the now empty main space mem map for the bump pointer temp space. 1655 mem_map.reset(main_space_->ReleaseMemMap()); 1656 // Unset the pointers just in case. 1657 if (dlmalloc_space_ == main_space_) { 1658 dlmalloc_space_ = nullptr; 1659 } else if (rosalloc_space_ == main_space_) { 1660 rosalloc_space_ = nullptr; 1661 } 1662 // Remove the main space so that we don't try to trim it, this doens't work for debug 1663 // builds since RosAlloc attempts to read the magic number from a protected page. 1664 RemoveSpace(main_space_); 1665 RemoveRememberedSet(main_space_); 1666 delete main_space_; // Delete the space since it has been removed. 1667 main_space_ = nullptr; 1668 RemoveRememberedSet(main_space_backup_.get()); 1669 main_space_backup_.reset(nullptr); // Deletes the space. 1670 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1671 mem_map.release()); 1672 AddSpace(temp_space_); 1673 } 1674 break; 1675 } 1676 case kCollectorTypeMS: 1677 // Fall through. 1678 case kCollectorTypeCMS: { 1679 if (IsMovingGc(collector_type_)) { 1680 CHECK(temp_space_ != nullptr); 1681 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1682 RemoveSpace(temp_space_); 1683 temp_space_ = nullptr; 1684 mem_map->Protect(PROT_READ | PROT_WRITE); 1685 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1686 mem_map->Size()); 1687 mem_map.release(); 1688 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1689 AddSpace(main_space_); 1690 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1691 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1692 RemoveSpace(bump_pointer_space_); 1693 bump_pointer_space_ = nullptr; 1694 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1695 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1696 if (kIsDebugBuild && kUseRosAlloc) { 1697 mem_map->Protect(PROT_READ | PROT_WRITE); 1698 } 1699 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1700 mem_map->Size(), mem_map->Size(), 1701 name, true)); 1702 if (kIsDebugBuild && kUseRosAlloc) { 1703 mem_map->Protect(PROT_NONE); 1704 } 1705 mem_map.release(); 1706 } 1707 break; 1708 } 1709 default: { 1710 LOG(FATAL) << "Attempted to transition to invalid collector type " 1711 << static_cast<size_t>(collector_type); 1712 break; 1713 } 1714 } 1715 ChangeCollector(collector_type); 1716 tl->ResumeAll(); 1717 // Can't call into java code with all threads suspended. 1718 reference_processor_.EnqueueClearedReferences(self); 1719 uint64_t duration = NanoTime() - start_time; 1720 GrowForUtilization(semi_space_collector_); 1721 FinishGC(self, collector::kGcTypeFull); 1722 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1723 int32_t delta_allocated = before_allocated - after_allocated; 1724 std::string saved_str; 1725 if (delta_allocated >= 0) { 1726 saved_str = " saved at least " + PrettySize(delta_allocated); 1727 } else { 1728 saved_str = " expanded " + PrettySize(-delta_allocated); 1729 } 1730 VLOG(gc) << "Heap transition to " << process_state_ << " took " 1731 << PrettyDuration(duration) << saved_str; 1732} 1733 1734void Heap::ChangeCollector(CollectorType collector_type) { 1735 // TODO: Only do this with all mutators suspended to avoid races. 1736 if (collector_type != collector_type_) { 1737 if (collector_type == kCollectorTypeMC) { 1738 // Don't allow mark compact unless support is compiled in. 1739 CHECK(kMarkCompactSupport); 1740 } 1741 collector_type_ = collector_type; 1742 gc_plan_.clear(); 1743 switch (collector_type_) { 1744 case kCollectorTypeCC: // Fall-through. 1745 case kCollectorTypeMC: // Fall-through. 1746 case kCollectorTypeSS: // Fall-through. 1747 case kCollectorTypeGSS: { 1748 gc_plan_.push_back(collector::kGcTypeFull); 1749 if (use_tlab_) { 1750 ChangeAllocator(kAllocatorTypeTLAB); 1751 } else { 1752 ChangeAllocator(kAllocatorTypeBumpPointer); 1753 } 1754 break; 1755 } 1756 case kCollectorTypeMS: { 1757 gc_plan_.push_back(collector::kGcTypeSticky); 1758 gc_plan_.push_back(collector::kGcTypePartial); 1759 gc_plan_.push_back(collector::kGcTypeFull); 1760 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1761 break; 1762 } 1763 case kCollectorTypeCMS: { 1764 gc_plan_.push_back(collector::kGcTypeSticky); 1765 gc_plan_.push_back(collector::kGcTypePartial); 1766 gc_plan_.push_back(collector::kGcTypeFull); 1767 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1768 break; 1769 } 1770 default: { 1771 LOG(FATAL) << "Unimplemented"; 1772 } 1773 } 1774 if (IsGcConcurrent()) { 1775 concurrent_start_bytes_ = 1776 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1777 } else { 1778 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1779 } 1780 } 1781} 1782 1783// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1784class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1785 public: 1786 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1787 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1788 } 1789 1790 void BuildBins(space::ContinuousSpace* space) { 1791 bin_live_bitmap_ = space->GetLiveBitmap(); 1792 bin_mark_bitmap_ = space->GetMarkBitmap(); 1793 BinContext context; 1794 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1795 context.collector_ = this; 1796 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1797 // Note: This requires traversing the space in increasing order of object addresses. 1798 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1799 // Add the last bin which spans after the last object to the end of the space. 1800 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1801 } 1802 1803 private: 1804 struct BinContext { 1805 uintptr_t prev_; // The end of the previous object. 1806 ZygoteCompactingCollector* collector_; 1807 }; 1808 // Maps from bin sizes to locations. 1809 std::multimap<size_t, uintptr_t> bins_; 1810 // Live bitmap of the space which contains the bins. 1811 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1812 // Mark bitmap of the space which contains the bins. 1813 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1814 1815 static void Callback(mirror::Object* obj, void* arg) 1816 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1817 DCHECK(arg != nullptr); 1818 BinContext* context = reinterpret_cast<BinContext*>(arg); 1819 ZygoteCompactingCollector* collector = context->collector_; 1820 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1821 size_t bin_size = object_addr - context->prev_; 1822 // Add the bin consisting of the end of the previous object to the start of the current object. 1823 collector->AddBin(bin_size, context->prev_); 1824 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1825 } 1826 1827 void AddBin(size_t size, uintptr_t position) { 1828 if (size != 0) { 1829 bins_.insert(std::make_pair(size, position)); 1830 } 1831 } 1832 1833 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1834 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1835 // allocator. 1836 return false; 1837 } 1838 1839 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1840 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1841 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1842 mirror::Object* forward_address; 1843 // Find the smallest bin which we can move obj in. 1844 auto it = bins_.lower_bound(object_size); 1845 if (it == bins_.end()) { 1846 // No available space in the bins, place it in the target space instead (grows the zygote 1847 // space). 1848 size_t bytes_allocated; 1849 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1850 if (to_space_live_bitmap_ != nullptr) { 1851 to_space_live_bitmap_->Set(forward_address); 1852 } else { 1853 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1854 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1855 } 1856 } else { 1857 size_t size = it->first; 1858 uintptr_t pos = it->second; 1859 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1860 forward_address = reinterpret_cast<mirror::Object*>(pos); 1861 // Set the live and mark bits so that sweeping system weaks works properly. 1862 bin_live_bitmap_->Set(forward_address); 1863 bin_mark_bitmap_->Set(forward_address); 1864 DCHECK_GE(size, object_size); 1865 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1866 } 1867 // Copy the object over to its new location. 1868 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1869 if (kUseBakerOrBrooksReadBarrier) { 1870 obj->AssertReadBarrierPointer(); 1871 if (kUseBrooksReadBarrier) { 1872 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1873 forward_address->SetReadBarrierPointer(forward_address); 1874 } 1875 forward_address->AssertReadBarrierPointer(); 1876 } 1877 return forward_address; 1878 } 1879}; 1880 1881void Heap::UnBindBitmaps() { 1882 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1883 for (const auto& space : GetContinuousSpaces()) { 1884 if (space->IsContinuousMemMapAllocSpace()) { 1885 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1886 if (alloc_space->HasBoundBitmaps()) { 1887 alloc_space->UnBindBitmaps(); 1888 } 1889 } 1890 } 1891} 1892 1893void Heap::PreZygoteFork() { 1894 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1895 Thread* self = Thread::Current(); 1896 MutexLock mu(self, zygote_creation_lock_); 1897 // Try to see if we have any Zygote spaces. 1898 if (have_zygote_space_) { 1899 return; 1900 } 1901 VLOG(heap) << "Starting PreZygoteFork"; 1902 // Trim the pages at the end of the non moving space. 1903 non_moving_space_->Trim(); 1904 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1905 // there. 1906 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1907 const bool same_space = non_moving_space_ == main_space_; 1908 if (kCompactZygote) { 1909 // Can't compact if the non moving space is the same as the main space. 1910 DCHECK(semi_space_collector_ != nullptr); 1911 // Temporarily disable rosalloc verification because the zygote 1912 // compaction will mess up the rosalloc internal metadata. 1913 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1914 ZygoteCompactingCollector zygote_collector(this); 1915 zygote_collector.BuildBins(non_moving_space_); 1916 // Create a new bump pointer space which we will compact into. 1917 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1918 non_moving_space_->Limit()); 1919 // Compact the bump pointer space to a new zygote bump pointer space. 1920 bool reset_main_space = false; 1921 if (IsMovingGc(collector_type_)) { 1922 zygote_collector.SetFromSpace(bump_pointer_space_); 1923 } else { 1924 CHECK(main_space_ != nullptr); 1925 // Copy from the main space. 1926 zygote_collector.SetFromSpace(main_space_); 1927 reset_main_space = true; 1928 } 1929 zygote_collector.SetToSpace(&target_space); 1930 zygote_collector.SetSwapSemiSpaces(false); 1931 zygote_collector.Run(kGcCauseCollectorTransition, false); 1932 if (reset_main_space) { 1933 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1934 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1935 MemMap* mem_map = main_space_->ReleaseMemMap(); 1936 RemoveSpace(main_space_); 1937 space::Space* old_main_space = main_space_; 1938 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1939 delete old_main_space; 1940 AddSpace(main_space_); 1941 } else { 1942 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1943 } 1944 if (temp_space_ != nullptr) { 1945 CHECK(temp_space_->IsEmpty()); 1946 } 1947 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1948 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1949 // Update the end and write out image. 1950 non_moving_space_->SetEnd(target_space.End()); 1951 non_moving_space_->SetLimit(target_space.Limit()); 1952 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1953 } 1954 // Change the collector to the post zygote one. 1955 ChangeCollector(foreground_collector_type_); 1956 // Save the old space so that we can remove it after we complete creating the zygote space. 1957 space::MallocSpace* old_alloc_space = non_moving_space_; 1958 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1959 // the remaining available space. 1960 // Remove the old space before creating the zygote space since creating the zygote space sets 1961 // the old alloc space's bitmaps to nullptr. 1962 RemoveSpace(old_alloc_space); 1963 if (collector::SemiSpace::kUseRememberedSet) { 1964 // Sanity bound check. 1965 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1966 // Remove the remembered set for the now zygote space (the old 1967 // non-moving space). Note now that we have compacted objects into 1968 // the zygote space, the data in the remembered set is no longer 1969 // needed. The zygote space will instead have a mod-union table 1970 // from this point on. 1971 RemoveRememberedSet(old_alloc_space); 1972 } 1973 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1974 low_memory_mode_, 1975 &non_moving_space_); 1976 CHECK(!non_moving_space_->CanMoveObjects()); 1977 if (same_space) { 1978 main_space_ = non_moving_space_; 1979 SetSpaceAsDefault(main_space_); 1980 } 1981 delete old_alloc_space; 1982 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1983 AddSpace(zygote_space); 1984 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1985 AddSpace(non_moving_space_); 1986 have_zygote_space_ = true; 1987 // Enable large object space allocations. 1988 large_object_threshold_ = kDefaultLargeObjectThreshold; 1989 // Create the zygote space mod union table. 1990 accounting::ModUnionTable* mod_union_table = 1991 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1992 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1993 AddModUnionTable(mod_union_table); 1994 if (collector::SemiSpace::kUseRememberedSet) { 1995 // Add a new remembered set for the post-zygote non-moving space. 1996 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1997 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1998 non_moving_space_); 1999 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 2000 << "Failed to create post-zygote non-moving space remembered set"; 2001 AddRememberedSet(post_zygote_non_moving_space_rem_set); 2002 } 2003} 2004 2005void Heap::FlushAllocStack() { 2006 MarkAllocStackAsLive(allocation_stack_.get()); 2007 allocation_stack_->Reset(); 2008} 2009 2010void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2011 accounting::ContinuousSpaceBitmap* bitmap2, 2012 accounting::LargeObjectBitmap* large_objects, 2013 accounting::ObjectStack* stack) { 2014 DCHECK(bitmap1 != nullptr); 2015 DCHECK(bitmap2 != nullptr); 2016 mirror::Object** limit = stack->End(); 2017 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2018 const mirror::Object* obj = *it; 2019 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2020 if (bitmap1->HasAddress(obj)) { 2021 bitmap1->Set(obj); 2022 } else if (bitmap2->HasAddress(obj)) { 2023 bitmap2->Set(obj); 2024 } else { 2025 large_objects->Set(obj); 2026 } 2027 } 2028 } 2029} 2030 2031void Heap::SwapSemiSpaces() { 2032 CHECK(bump_pointer_space_ != nullptr); 2033 CHECK(temp_space_ != nullptr); 2034 std::swap(bump_pointer_space_, temp_space_); 2035} 2036 2037void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2038 space::ContinuousMemMapAllocSpace* source_space, 2039 GcCause gc_cause) { 2040 CHECK(kMovingCollector); 2041 if (target_space != source_space) { 2042 // Don't swap spaces since this isn't a typical semi space collection. 2043 semi_space_collector_->SetSwapSemiSpaces(false); 2044 semi_space_collector_->SetFromSpace(source_space); 2045 semi_space_collector_->SetToSpace(target_space); 2046 semi_space_collector_->Run(gc_cause, false); 2047 } else { 2048 CHECK(target_space->IsBumpPointerSpace()) 2049 << "In-place compaction is only supported for bump pointer spaces"; 2050 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2051 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2052 } 2053} 2054 2055collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2056 bool clear_soft_references) { 2057 Thread* self = Thread::Current(); 2058 Runtime* runtime = Runtime::Current(); 2059 // If the heap can't run the GC, silently fail and return that no GC was run. 2060 switch (gc_type) { 2061 case collector::kGcTypePartial: { 2062 if (!have_zygote_space_) { 2063 return collector::kGcTypeNone; 2064 } 2065 break; 2066 } 2067 default: { 2068 // Other GC types don't have any special cases which makes them not runnable. The main case 2069 // here is full GC. 2070 } 2071 } 2072 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2073 Locks::mutator_lock_->AssertNotHeld(self); 2074 if (self->IsHandlingStackOverflow()) { 2075 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2076 } 2077 bool compacting_gc; 2078 { 2079 gc_complete_lock_->AssertNotHeld(self); 2080 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2081 MutexLock mu(self, *gc_complete_lock_); 2082 // Ensure there is only one GC at a time. 2083 WaitForGcToCompleteLocked(gc_cause, self); 2084 compacting_gc = IsMovingGc(collector_type_); 2085 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2086 if (compacting_gc && disable_moving_gc_count_ != 0) { 2087 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2088 return collector::kGcTypeNone; 2089 } 2090 collector_type_running_ = collector_type_; 2091 } 2092 2093 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2094 ++runtime->GetStats()->gc_for_alloc_count; 2095 ++self->GetStats()->gc_for_alloc_count; 2096 } 2097 uint64_t gc_start_time_ns = NanoTime(); 2098 uint64_t gc_start_size = GetBytesAllocated(); 2099 // Approximate allocation rate in bytes / second. 2100 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2101 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2102 if (LIKELY(ms_delta != 0)) { 2103 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2104 ATRACE_INT("Allocation rate KB/s", allocation_rate_ / KB); 2105 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2106 } 2107 2108 DCHECK_LT(gc_type, collector::kGcTypeMax); 2109 DCHECK_NE(gc_type, collector::kGcTypeNone); 2110 2111 collector::GarbageCollector* collector = nullptr; 2112 // TODO: Clean this up. 2113 if (compacting_gc) { 2114 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2115 current_allocator_ == kAllocatorTypeTLAB); 2116 switch (collector_type_) { 2117 case kCollectorTypeSS: 2118 // Fall-through. 2119 case kCollectorTypeGSS: 2120 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2121 semi_space_collector_->SetToSpace(temp_space_); 2122 semi_space_collector_->SetSwapSemiSpaces(true); 2123 collector = semi_space_collector_; 2124 break; 2125 case kCollectorTypeCC: 2126 collector = concurrent_copying_collector_; 2127 break; 2128 case kCollectorTypeMC: 2129 mark_compact_collector_->SetSpace(bump_pointer_space_); 2130 collector = mark_compact_collector_; 2131 break; 2132 default: 2133 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2134 } 2135 if (collector != mark_compact_collector_) { 2136 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2137 CHECK(temp_space_->IsEmpty()); 2138 } 2139 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2140 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2141 current_allocator_ == kAllocatorTypeDlMalloc) { 2142 collector = FindCollectorByGcType(gc_type); 2143 } else { 2144 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2145 } 2146 CHECK(collector != nullptr) 2147 << "Could not find garbage collector with collector_type=" 2148 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2149 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2150 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2151 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2152 RequestHeapTrim(); 2153 // Enqueue cleared references. 2154 reference_processor_.EnqueueClearedReferences(self); 2155 // Grow the heap so that we know when to perform the next GC. 2156 GrowForUtilization(collector); 2157 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2158 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2159 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2160 // (mutator time blocked >= long_pause_log_threshold_). 2161 bool log_gc = gc_cause == kGcCauseExplicit; 2162 if (!log_gc && CareAboutPauseTimes()) { 2163 // GC for alloc pauses the allocating thread, so consider it as a pause. 2164 log_gc = duration > long_gc_log_threshold_ || 2165 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2166 for (uint64_t pause : pause_times) { 2167 log_gc = log_gc || pause >= long_pause_log_threshold_; 2168 } 2169 } 2170 if (log_gc) { 2171 const size_t percent_free = GetPercentFree(); 2172 const size_t current_heap_size = GetBytesAllocated(); 2173 const size_t total_memory = GetTotalMemory(); 2174 std::ostringstream pause_string; 2175 for (size_t i = 0; i < pause_times.size(); ++i) { 2176 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2177 << ((i != pause_times.size() - 1) ? "," : ""); 2178 } 2179 LOG(INFO) << gc_cause << " " << collector->GetName() 2180 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2181 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2182 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2183 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2184 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2185 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2186 << " total " << PrettyDuration((duration / 1000) * 1000); 2187 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2188 } 2189 FinishGC(self, gc_type); 2190 // Inform DDMS that a GC completed. 2191 Dbg::GcDidFinish(); 2192 return gc_type; 2193} 2194 2195void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2196 MutexLock mu(self, *gc_complete_lock_); 2197 collector_type_running_ = kCollectorTypeNone; 2198 if (gc_type != collector::kGcTypeNone) { 2199 last_gc_type_ = gc_type; 2200 } 2201 // Wake anyone who may have been waiting for the GC to complete. 2202 gc_complete_cond_->Broadcast(self); 2203} 2204 2205static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2206 RootType /*root_type*/) { 2207 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2208 if (*root == obj) { 2209 LOG(INFO) << "Object " << obj << " is a root"; 2210 } 2211} 2212 2213class ScanVisitor { 2214 public: 2215 void operator()(const mirror::Object* obj) const { 2216 LOG(ERROR) << "Would have rescanned object " << obj; 2217 } 2218}; 2219 2220// Verify a reference from an object. 2221class VerifyReferenceVisitor { 2222 public: 2223 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2224 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2225 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2226 2227 size_t GetFailureCount() const { 2228 return fail_count_->LoadSequentiallyConsistent(); 2229 } 2230 2231 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2232 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2233 if (verify_referent_) { 2234 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2235 } 2236 } 2237 2238 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2239 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2240 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2241 } 2242 2243 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2244 return heap_->IsLiveObjectLocked(obj, true, false, true); 2245 } 2246 2247 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2248 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2249 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2250 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2251 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2252 << " thread_id= " << thread_id << " root_type= " << root_type; 2253 } 2254 } 2255 2256 private: 2257 // TODO: Fix the no thread safety analysis. 2258 // Returns false on failure. 2259 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2260 NO_THREAD_SAFETY_ANALYSIS { 2261 if (ref == nullptr || IsLive(ref)) { 2262 // Verify that the reference is live. 2263 return true; 2264 } 2265 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2266 // Print message on only on first failure to prevent spam. 2267 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2268 } 2269 if (obj != nullptr) { 2270 // Only do this part for non roots. 2271 accounting::CardTable* card_table = heap_->GetCardTable(); 2272 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2273 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2274 byte* card_addr = card_table->CardFromAddr(obj); 2275 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2276 << offset << "\n card value = " << static_cast<int>(*card_addr); 2277 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2278 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2279 } else { 2280 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2281 } 2282 2283 // Attempt to find the class inside of the recently freed objects. 2284 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2285 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2286 space::MallocSpace* space = ref_space->AsMallocSpace(); 2287 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2288 if (ref_class != nullptr) { 2289 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2290 << PrettyClass(ref_class); 2291 } else { 2292 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2293 } 2294 } 2295 2296 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2297 ref->GetClass()->IsClass()) { 2298 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2299 } else { 2300 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2301 << ") is not a valid heap address"; 2302 } 2303 2304 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2305 void* cover_begin = card_table->AddrFromCard(card_addr); 2306 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2307 accounting::CardTable::kCardSize); 2308 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2309 << "-" << cover_end; 2310 accounting::ContinuousSpaceBitmap* bitmap = 2311 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2312 2313 if (bitmap == nullptr) { 2314 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2315 if (!VerifyClassClass(obj->GetClass())) { 2316 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2317 } 2318 } else { 2319 // Print out how the object is live. 2320 if (bitmap->Test(obj)) { 2321 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2322 } 2323 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2324 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2325 } 2326 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2327 LOG(ERROR) << "Object " << obj << " found in live stack"; 2328 } 2329 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2330 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2331 } 2332 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2333 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2334 } 2335 // Attempt to see if the card table missed the reference. 2336 ScanVisitor scan_visitor; 2337 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2338 card_table->Scan(bitmap, byte_cover_begin, 2339 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2340 } 2341 2342 // Search to see if any of the roots reference our object. 2343 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2344 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2345 2346 // Search to see if any of the roots reference our reference. 2347 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2348 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2349 } 2350 return false; 2351 } 2352 2353 Heap* const heap_; 2354 Atomic<size_t>* const fail_count_; 2355 const bool verify_referent_; 2356}; 2357 2358// Verify all references within an object, for use with HeapBitmap::Visit. 2359class VerifyObjectVisitor { 2360 public: 2361 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2362 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2363 } 2364 2365 void operator()(mirror::Object* obj) const 2366 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2367 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2368 // be live or else how did we find it in the live bitmap? 2369 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2370 // The class doesn't count as a reference but we should verify it anyways. 2371 obj->VisitReferences<true>(visitor, visitor); 2372 } 2373 2374 static void VisitCallback(mirror::Object* obj, void* arg) 2375 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2376 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2377 visitor->operator()(obj); 2378 } 2379 2380 size_t GetFailureCount() const { 2381 return fail_count_->LoadSequentiallyConsistent(); 2382 } 2383 2384 private: 2385 Heap* const heap_; 2386 Atomic<size_t>* const fail_count_; 2387 const bool verify_referent_; 2388}; 2389 2390void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2391 // Slow path, the allocation stack push back must have already failed. 2392 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2393 do { 2394 // TODO: Add handle VerifyObject. 2395 StackHandleScope<1> hs(self); 2396 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2397 // Push our object into the reserve region of the allocaiton stack. This is only required due 2398 // to heap verification requiring that roots are live (either in the live bitmap or in the 2399 // allocation stack). 2400 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2401 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2402 } while (!allocation_stack_->AtomicPushBack(*obj)); 2403} 2404 2405void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2406 // Slow path, the allocation stack push back must have already failed. 2407 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2408 mirror::Object** start_address; 2409 mirror::Object** end_address; 2410 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2411 &end_address)) { 2412 // TODO: Add handle VerifyObject. 2413 StackHandleScope<1> hs(self); 2414 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2415 // Push our object into the reserve region of the allocaiton stack. This is only required due 2416 // to heap verification requiring that roots are live (either in the live bitmap or in the 2417 // allocation stack). 2418 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2419 // Push into the reserve allocation stack. 2420 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2421 } 2422 self->SetThreadLocalAllocationStack(start_address, end_address); 2423 // Retry on the new thread-local allocation stack. 2424 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2425} 2426 2427// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2428size_t Heap::VerifyHeapReferences(bool verify_referents) { 2429 Thread* self = Thread::Current(); 2430 Locks::mutator_lock_->AssertExclusiveHeld(self); 2431 // Lets sort our allocation stacks so that we can efficiently binary search them. 2432 allocation_stack_->Sort(); 2433 live_stack_->Sort(); 2434 // Since we sorted the allocation stack content, need to revoke all 2435 // thread-local allocation stacks. 2436 RevokeAllThreadLocalAllocationStacks(self); 2437 Atomic<size_t> fail_count_(0); 2438 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2439 // Verify objects in the allocation stack since these will be objects which were: 2440 // 1. Allocated prior to the GC (pre GC verification). 2441 // 2. Allocated during the GC (pre sweep GC verification). 2442 // We don't want to verify the objects in the live stack since they themselves may be 2443 // pointing to dead objects if they are not reachable. 2444 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2445 // Verify the roots: 2446 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2447 if (visitor.GetFailureCount() > 0) { 2448 // Dump mod-union tables. 2449 for (const auto& table_pair : mod_union_tables_) { 2450 accounting::ModUnionTable* mod_union_table = table_pair.second; 2451 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2452 } 2453 // Dump remembered sets. 2454 for (const auto& table_pair : remembered_sets_) { 2455 accounting::RememberedSet* remembered_set = table_pair.second; 2456 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2457 } 2458 DumpSpaces(LOG(ERROR)); 2459 } 2460 return visitor.GetFailureCount(); 2461} 2462 2463class VerifyReferenceCardVisitor { 2464 public: 2465 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2466 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2467 Locks::heap_bitmap_lock_) 2468 : heap_(heap), failed_(failed) { 2469 } 2470 2471 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2472 // annotalysis on visitors. 2473 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2474 NO_THREAD_SAFETY_ANALYSIS { 2475 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2476 // Filter out class references since changing an object's class does not mark the card as dirty. 2477 // Also handles large objects, since the only reference they hold is a class reference. 2478 if (ref != nullptr && !ref->IsClass()) { 2479 accounting::CardTable* card_table = heap_->GetCardTable(); 2480 // If the object is not dirty and it is referencing something in the live stack other than 2481 // class, then it must be on a dirty card. 2482 if (!card_table->AddrIsInCardTable(obj)) { 2483 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2484 *failed_ = true; 2485 } else if (!card_table->IsDirty(obj)) { 2486 // TODO: Check mod-union tables. 2487 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2488 // kCardDirty - 1 if it didnt get touched since we aged it. 2489 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2490 if (live_stack->ContainsSorted(ref)) { 2491 if (live_stack->ContainsSorted(obj)) { 2492 LOG(ERROR) << "Object " << obj << " found in live stack"; 2493 } 2494 if (heap_->GetLiveBitmap()->Test(obj)) { 2495 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2496 } 2497 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2498 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2499 2500 // Print which field of the object is dead. 2501 if (!obj->IsObjectArray()) { 2502 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2503 CHECK(klass != NULL); 2504 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2505 : klass->GetIFields(); 2506 CHECK(fields != NULL); 2507 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2508 mirror::ArtField* cur = fields->Get(i); 2509 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2510 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2511 << PrettyField(cur); 2512 break; 2513 } 2514 } 2515 } else { 2516 mirror::ObjectArray<mirror::Object>* object_array = 2517 obj->AsObjectArray<mirror::Object>(); 2518 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2519 if (object_array->Get(i) == ref) { 2520 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2521 } 2522 } 2523 } 2524 2525 *failed_ = true; 2526 } 2527 } 2528 } 2529 } 2530 2531 private: 2532 Heap* const heap_; 2533 bool* const failed_; 2534}; 2535 2536class VerifyLiveStackReferences { 2537 public: 2538 explicit VerifyLiveStackReferences(Heap* heap) 2539 : heap_(heap), 2540 failed_(false) {} 2541 2542 void operator()(mirror::Object* obj) const 2543 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2544 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2545 obj->VisitReferences<true>(visitor, VoidFunctor()); 2546 } 2547 2548 bool Failed() const { 2549 return failed_; 2550 } 2551 2552 private: 2553 Heap* const heap_; 2554 bool failed_; 2555}; 2556 2557bool Heap::VerifyMissingCardMarks() { 2558 Thread* self = Thread::Current(); 2559 Locks::mutator_lock_->AssertExclusiveHeld(self); 2560 // We need to sort the live stack since we binary search it. 2561 live_stack_->Sort(); 2562 // Since we sorted the allocation stack content, need to revoke all 2563 // thread-local allocation stacks. 2564 RevokeAllThreadLocalAllocationStacks(self); 2565 VerifyLiveStackReferences visitor(this); 2566 GetLiveBitmap()->Visit(visitor); 2567 // We can verify objects in the live stack since none of these should reference dead objects. 2568 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2569 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2570 visitor(*it); 2571 } 2572 } 2573 return !visitor.Failed(); 2574} 2575 2576void Heap::SwapStacks(Thread* self) { 2577 if (kUseThreadLocalAllocationStack) { 2578 live_stack_->AssertAllZero(); 2579 } 2580 allocation_stack_.swap(live_stack_); 2581} 2582 2583void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2584 // This must be called only during the pause. 2585 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2586 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2587 MutexLock mu2(self, *Locks::thread_list_lock_); 2588 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2589 for (Thread* t : thread_list) { 2590 t->RevokeThreadLocalAllocationStack(); 2591 } 2592} 2593 2594void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2595 if (kIsDebugBuild) { 2596 if (bump_pointer_space_ != nullptr) { 2597 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2598 } 2599 } 2600} 2601 2602accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2603 auto it = mod_union_tables_.find(space); 2604 if (it == mod_union_tables_.end()) { 2605 return nullptr; 2606 } 2607 return it->second; 2608} 2609 2610accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2611 auto it = remembered_sets_.find(space); 2612 if (it == remembered_sets_.end()) { 2613 return nullptr; 2614 } 2615 return it->second; 2616} 2617 2618void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2619 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2620 // Clear cards and keep track of cards cleared in the mod-union table. 2621 for (const auto& space : continuous_spaces_) { 2622 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2623 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2624 if (table != nullptr) { 2625 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2626 "ImageModUnionClearCards"; 2627 TimingLogger::ScopedTiming t(name, timings); 2628 table->ClearCards(); 2629 } else if (use_rem_sets && rem_set != nullptr) { 2630 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2631 << static_cast<int>(collector_type_); 2632 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2633 rem_set->ClearCards(); 2634 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2635 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2636 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2637 // were dirty before the GC started. 2638 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2639 // -> clean(cleaning thread). 2640 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2641 // roots and then we scan / update mod union tables after. We will always scan either card. 2642 // If we end up with the non aged card, we scan it it in the pause. 2643 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2644 VoidFunctor()); 2645 } 2646 } 2647} 2648 2649static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2650} 2651 2652void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2653 Thread* const self = Thread::Current(); 2654 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2655 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2656 if (verify_pre_gc_heap_) { 2657 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2658 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2659 size_t failures = VerifyHeapReferences(); 2660 if (failures > 0) { 2661 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2662 << " failures"; 2663 } 2664 } 2665 // Check that all objects which reference things in the live stack are on dirty cards. 2666 if (verify_missing_card_marks_) { 2667 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2668 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2669 SwapStacks(self); 2670 // Sort the live stack so that we can quickly binary search it later. 2671 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2672 << " missing card mark verification failed\n" << DumpSpaces(); 2673 SwapStacks(self); 2674 } 2675 if (verify_mod_union_table_) { 2676 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2677 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2678 for (const auto& table_pair : mod_union_tables_) { 2679 accounting::ModUnionTable* mod_union_table = table_pair.second; 2680 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2681 mod_union_table->Verify(); 2682 } 2683 } 2684} 2685 2686void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2687 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2688 collector::GarbageCollector::ScopedPause pause(gc); 2689 PreGcVerificationPaused(gc); 2690 } 2691} 2692 2693void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2694 // TODO: Add a new runtime option for this? 2695 if (verify_pre_gc_rosalloc_) { 2696 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2697 } 2698} 2699 2700void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2701 Thread* const self = Thread::Current(); 2702 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2703 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2704 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2705 // reachable objects. 2706 if (verify_pre_sweeping_heap_) { 2707 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2708 CHECK_NE(self->GetState(), kRunnable); 2709 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2710 // Swapping bound bitmaps does nothing. 2711 gc->SwapBitmaps(); 2712 // Pass in false since concurrent reference processing can mean that the reference referents 2713 // may point to dead objects at the point which PreSweepingGcVerification is called. 2714 size_t failures = VerifyHeapReferences(false); 2715 if (failures > 0) { 2716 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2717 << " failures"; 2718 } 2719 gc->SwapBitmaps(); 2720 } 2721 if (verify_pre_sweeping_rosalloc_) { 2722 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2723 } 2724} 2725 2726void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2727 // Only pause if we have to do some verification. 2728 Thread* const self = Thread::Current(); 2729 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2730 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2731 if (verify_system_weaks_) { 2732 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2733 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2734 mark_sweep->VerifySystemWeaks(); 2735 } 2736 if (verify_post_gc_rosalloc_) { 2737 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2738 } 2739 if (verify_post_gc_heap_) { 2740 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2741 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2742 size_t failures = VerifyHeapReferences(); 2743 if (failures > 0) { 2744 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2745 << " failures"; 2746 } 2747 } 2748} 2749 2750void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2751 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2752 collector::GarbageCollector::ScopedPause pause(gc); 2753 PostGcVerificationPaused(gc); 2754 } 2755} 2756 2757void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2758 TimingLogger::ScopedTiming t(name, timings); 2759 for (const auto& space : continuous_spaces_) { 2760 if (space->IsRosAllocSpace()) { 2761 VLOG(heap) << name << " : " << space->GetName(); 2762 space->AsRosAllocSpace()->Verify(); 2763 } 2764 } 2765} 2766 2767collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2768 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2769 MutexLock mu(self, *gc_complete_lock_); 2770 return WaitForGcToCompleteLocked(cause, self); 2771} 2772 2773collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2774 collector::GcType last_gc_type = collector::kGcTypeNone; 2775 uint64_t wait_start = NanoTime(); 2776 while (collector_type_running_ != kCollectorTypeNone) { 2777 ATRACE_BEGIN("GC: Wait For Completion"); 2778 // We must wait, change thread state then sleep on gc_complete_cond_; 2779 gc_complete_cond_->Wait(self); 2780 last_gc_type = last_gc_type_; 2781 ATRACE_END(); 2782 } 2783 uint64_t wait_time = NanoTime() - wait_start; 2784 total_wait_time_ += wait_time; 2785 if (wait_time > long_pause_log_threshold_) { 2786 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2787 << " for cause " << cause; 2788 } 2789 return last_gc_type; 2790} 2791 2792void Heap::DumpForSigQuit(std::ostream& os) { 2793 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2794 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2795 DumpGcPerformanceInfo(os); 2796} 2797 2798size_t Heap::GetPercentFree() { 2799 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2800} 2801 2802void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2803 if (max_allowed_footprint > GetMaxMemory()) { 2804 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2805 << PrettySize(GetMaxMemory()); 2806 max_allowed_footprint = GetMaxMemory(); 2807 } 2808 max_allowed_footprint_ = max_allowed_footprint; 2809} 2810 2811bool Heap::IsMovableObject(const mirror::Object* obj) const { 2812 if (kMovingCollector) { 2813 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2814 if (space != nullptr) { 2815 // TODO: Check large object? 2816 return space->CanMoveObjects(); 2817 } 2818 } 2819 return false; 2820} 2821 2822void Heap::UpdateMaxNativeFootprint() { 2823 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2824 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2825 size_t target_size = native_size / GetTargetHeapUtilization(); 2826 if (target_size > native_size + max_free_) { 2827 target_size = native_size + max_free_; 2828 } else if (target_size < native_size + min_free_) { 2829 target_size = native_size + min_free_; 2830 } 2831 native_footprint_gc_watermark_ = target_size; 2832 native_footprint_limit_ = 2 * target_size - native_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 have_zygote_space_ ? 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, int 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 = have_zygote_space_ ? 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 > native_footprint_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 > native_footprint_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, int bytes) { 3131 int expected_size, new_size; 3132 do { 3133 expected_size = native_bytes_allocated_.LoadRelaxed(); 3134 new_size = expected_size - bytes; 3135 if (UNLIKELY(new_size < 0)) { 3136 ScopedObjectAccess soa(env); 3137 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3138 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 3139 "registered as allocated", bytes, expected_size).c_str()); 3140 break; 3141 } 3142 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, new_size)); 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