heap.cc revision 20ed5af7a623a2d095082f8d6f53151c46fb8842
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <memory> 24#include <vector> 25 26#include "base/allocator.h" 27#include "base/dumpable.h" 28#include "base/histogram-inl.h" 29#include "base/stl_util.h" 30#include "common_throws.h" 31#include "cutils/sched_policy.h" 32#include "debugger.h" 33#include "gc/accounting/atomic_stack.h" 34#include "gc/accounting/card_table-inl.h" 35#include "gc/accounting/heap_bitmap-inl.h" 36#include "gc/accounting/mod_union_table.h" 37#include "gc/accounting/mod_union_table-inl.h" 38#include "gc/accounting/remembered_set.h" 39#include "gc/accounting/space_bitmap-inl.h" 40#include "gc/collector/concurrent_copying.h" 41#include "gc/collector/mark_compact.h" 42#include "gc/collector/mark_sweep-inl.h" 43#include "gc/collector/partial_mark_sweep.h" 44#include "gc/collector/semi_space.h" 45#include "gc/collector/sticky_mark_sweep.h" 46#include "gc/reference_processor.h" 47#include "gc/space/bump_pointer_space.h" 48#include "gc/space/dlmalloc_space-inl.h" 49#include "gc/space/image_space.h" 50#include "gc/space/large_object_space.h" 51#include "gc/space/rosalloc_space-inl.h" 52#include "gc/space/space-inl.h" 53#include "gc/space/zygote_space.h" 54#include "entrypoints/quick/quick_alloc_entrypoints.h" 55#include "heap-inl.h" 56#include "image.h" 57#include "intern_table.h" 58#include "mirror/art_field-inl.h" 59#include "mirror/class-inl.h" 60#include "mirror/object.h" 61#include "mirror/object-inl.h" 62#include "mirror/object_array-inl.h" 63#include "mirror/reference-inl.h" 64#include "os.h" 65#include "reflection.h" 66#include "runtime.h" 67#include "ScopedLocalRef.h" 68#include "scoped_thread_state_change.h" 69#include "handle_scope-inl.h" 70#include "thread_list.h" 71#include "well_known_classes.h" 72 73namespace art { 74 75namespace gc { 76 77static constexpr size_t kCollectorTransitionStressIterations = 0; 78static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 79static constexpr bool kGCALotMode = false; 80static constexpr size_t kGcAlotInterval = KB; 81// Minimum amount of remaining bytes before a concurrent GC is triggered. 82static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 83static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 84// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 85// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 86// threads (lower pauses, use less memory bandwidth). 87static constexpr double kStickyGcThroughputAdjustment = 1.0; 88// Whether or not we compact the zygote in PreZygoteFork. 89static constexpr bool kCompactZygote = kMovingCollector; 90// How many reserve entries are at the end of the allocation stack, these are only needed if the 91// allocation stack overflows. 92static constexpr size_t kAllocationStackReserveSize = 1024; 93// Default mark stack size in bytes. 94static const size_t kDefaultMarkStackSize = 64 * KB; 95// Define space name. 96static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 97static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 98static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 99static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 100 101Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 102 double target_utilization, double foreground_heap_growth_multiplier, 103 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 104 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 105 CollectorType background_collector_type, 106 space::LargeObjectSpaceType large_object_space_type, size_t large_object_threshold, 107 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 108 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 109 bool ignore_max_footprint, bool use_tlab, 110 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 111 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 112 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 113 uint64_t min_interval_homogeneous_space_compaction_by_oom) 114 : non_moving_space_(nullptr), 115 rosalloc_space_(nullptr), 116 dlmalloc_space_(nullptr), 117 main_space_(nullptr), 118 collector_type_(kCollectorTypeNone), 119 foreground_collector_type_(foreground_collector_type), 120 background_collector_type_(background_collector_type), 121 desired_collector_type_(foreground_collector_type_), 122 heap_trim_request_lock_(nullptr), 123 last_trim_time_(0), 124 heap_transition_or_trim_target_time_(0), 125 heap_trim_request_pending_(false), 126 parallel_gc_threads_(parallel_gc_threads), 127 conc_gc_threads_(conc_gc_threads), 128 low_memory_mode_(low_memory_mode), 129 long_pause_log_threshold_(long_pause_log_threshold), 130 long_gc_log_threshold_(long_gc_log_threshold), 131 ignore_max_footprint_(ignore_max_footprint), 132 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 133 zygote_space_(nullptr), 134 large_object_threshold_(large_object_threshold), 135 collector_type_running_(kCollectorTypeNone), 136 last_gc_type_(collector::kGcTypeNone), 137 next_gc_type_(collector::kGcTypePartial), 138 capacity_(capacity), 139 growth_limit_(growth_limit), 140 max_allowed_footprint_(initial_size), 141 native_footprint_gc_watermark_(initial_size), 142 native_need_to_run_finalization_(false), 143 // Initially assume we perceive jank in case the process state is never updated. 144 process_state_(kProcessStateJankPerceptible), 145 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 146 total_bytes_freed_ever_(0), 147 total_objects_freed_ever_(0), 148 num_bytes_allocated_(0), 149 native_bytes_allocated_(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 const bool is_zygote = Runtime::Current()->IsZygote(); 193 if (!is_zygote) { 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 uint8_t* requested_alloc_space_begin = nullptr; 205 if (!image_file_name.empty()) { 206 std::string error_msg; 207 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 208 image_instruction_set, 209 &error_msg); 210 if (image_space != nullptr) { 211 AddSpace(image_space); 212 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 213 // isn't going to get in the middle 214 uint8_t* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 215 CHECK_GT(oat_file_end_addr, image_space->End()); 216 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 217 } else { 218 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 219 << "Attempting to fall back to imageless running. Error was: " << error_msg; 220 } 221 } 222 /* 223 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 224 +- nonmoving space (non_moving_space_capacity)+- 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 226 +-????????????????????????????????????????????+- 227 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 228 +-main alloc space / bump space 1 (capacity_) +- 229 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 230 +-????????????????????????????????????????????+- 231 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 232 +-main alloc space2 / bump space 2 (capacity_)+- 233 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 234 */ 235 // We don't have hspace compaction enabled with GSS. 236 if (foreground_collector_type_ == kCollectorTypeGSS) { 237 use_homogeneous_space_compaction_for_oom_ = false; 238 } 239 bool support_homogeneous_space_compaction = 240 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 241 use_homogeneous_space_compaction_for_oom_; 242 // We may use the same space the main space for the non moving space if we don't need to compact 243 // from the main space. 244 // This is not the case if we support homogeneous compaction or have a moving background 245 // collector type. 246 bool separate_non_moving_space = is_zygote || 247 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 248 IsMovingGc(background_collector_type_); 249 if (foreground_collector_type == kCollectorTypeGSS) { 250 separate_non_moving_space = false; 251 } 252 std::unique_ptr<MemMap> main_mem_map_1; 253 std::unique_ptr<MemMap> main_mem_map_2; 254 uint8_t* request_begin = requested_alloc_space_begin; 255 if (request_begin != nullptr && separate_non_moving_space) { 256 request_begin += non_moving_space_capacity; 257 } 258 std::string error_str; 259 std::unique_ptr<MemMap> non_moving_space_mem_map; 260 if (separate_non_moving_space) { 261 // Reserve the non moving mem map before the other two since it needs to be at a specific 262 // address. 263 non_moving_space_mem_map.reset( 264 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 265 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 266 CHECK(non_moving_space_mem_map != nullptr) << error_str; 267 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 268 request_begin = reinterpret_cast<uint8_t*>(300 * MB); 269 } 270 // Attempt to create 2 mem maps at or after the requested begin. 271 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 272 &error_str)); 273 CHECK(main_mem_map_1.get() != nullptr) << error_str; 274 if (support_homogeneous_space_compaction || 275 background_collector_type_ == kCollectorTypeSS || 276 foreground_collector_type_ == kCollectorTypeSS) { 277 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 278 capacity_, &error_str)); 279 CHECK(main_mem_map_2.get() != nullptr) << error_str; 280 } 281 // Create the non moving space first so that bitmaps don't take up the address range. 282 if (separate_non_moving_space) { 283 // Non moving space is always dlmalloc since we currently don't have support for multiple 284 // active rosalloc spaces. 285 const size_t size = non_moving_space_mem_map->Size(); 286 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 287 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 288 initial_size, size, size, false); 289 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 290 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 291 << requested_alloc_space_begin; 292 AddSpace(non_moving_space_); 293 } 294 // Create other spaces based on whether or not we have a moving GC. 295 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 296 // Create bump pointer spaces. 297 // We only to create the bump pointer if the foreground collector is a compacting GC. 298 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 299 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 300 main_mem_map_1.release()); 301 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 302 AddSpace(bump_pointer_space_); 303 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 304 main_mem_map_2.release()); 305 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 306 AddSpace(temp_space_); 307 CHECK(separate_non_moving_space); 308 } else { 309 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 310 CHECK(main_space_ != nullptr); 311 AddSpace(main_space_); 312 if (!separate_non_moving_space) { 313 non_moving_space_ = main_space_; 314 CHECK(!non_moving_space_->CanMoveObjects()); 315 } 316 if (foreground_collector_type_ == kCollectorTypeGSS) { 317 CHECK_EQ(foreground_collector_type_, background_collector_type_); 318 // Create bump pointer spaces instead of a backup space. 319 main_mem_map_2.release(); 320 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 321 kGSSBumpPointerSpaceCapacity, nullptr); 322 CHECK(bump_pointer_space_ != nullptr); 323 AddSpace(bump_pointer_space_); 324 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 325 kGSSBumpPointerSpaceCapacity, nullptr); 326 CHECK(temp_space_ != nullptr); 327 AddSpace(temp_space_); 328 } else if (main_mem_map_2.get() != nullptr) { 329 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 330 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 331 growth_limit_, capacity_, name, true)); 332 CHECK(main_space_backup_.get() != nullptr); 333 // Add the space so its accounted for in the heap_begin and heap_end. 334 AddSpace(main_space_backup_.get()); 335 } 336 } 337 CHECK(non_moving_space_ != nullptr); 338 CHECK(!non_moving_space_->CanMoveObjects()); 339 // Allocate the large object space. 340 if (large_object_space_type == space::kLargeObjectSpaceTypeFreeList) { 341 large_object_space_ = space::FreeListSpace::Create("free list large object space", nullptr, 342 capacity_); 343 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 344 } else if (large_object_space_type == space::kLargeObjectSpaceTypeMap) { 345 large_object_space_ = space::LargeObjectMapSpace::Create("mem map large object space"); 346 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 347 } else { 348 // Disable the large object space by making the cutoff excessively large. 349 large_object_threshold_ = std::numeric_limits<size_t>::max(); 350 large_object_space_ = nullptr; 351 } 352 if (large_object_space_ != nullptr) { 353 AddSpace(large_object_space_); 354 } 355 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 356 CHECK(!continuous_spaces_.empty()); 357 // Relies on the spaces being sorted. 358 uint8_t* heap_begin = continuous_spaces_.front()->Begin(); 359 uint8_t* heap_end = continuous_spaces_.back()->Limit(); 360 size_t heap_capacity = heap_end - heap_begin; 361 // Remove the main backup space since it slows down the GC to have unused extra spaces. 362 if (main_space_backup_.get() != nullptr) { 363 RemoveSpace(main_space_backup_.get()); 364 } 365 // Allocate the card table. 366 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 367 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 368 // Card cache for now since it makes it easier for us to update the references to the copying 369 // spaces. 370 accounting::ModUnionTable* mod_union_table = 371 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 372 GetImageSpace()); 373 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 374 AddModUnionTable(mod_union_table); 375 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 376 accounting::RememberedSet* non_moving_space_rem_set = 377 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 378 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 379 AddRememberedSet(non_moving_space_rem_set); 380 } 381 // TODO: Count objects in the image space here? 382 num_bytes_allocated_.StoreRelaxed(0); 383 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 384 kDefaultMarkStackSize)); 385 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 386 allocation_stack_.reset(accounting::ObjectStack::Create( 387 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 388 live_stack_.reset(accounting::ObjectStack::Create( 389 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 390 // It's still too early to take a lock because there are no threads yet, but we can create locks 391 // now. We don't create it earlier to make it clear that you can't use locks during heap 392 // initialization. 393 gc_complete_lock_ = new Mutex("GC complete lock"); 394 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 395 *gc_complete_lock_)); 396 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 397 last_gc_size_ = GetBytesAllocated(); 398 if (ignore_max_footprint_) { 399 SetIdealFootprint(std::numeric_limits<size_t>::max()); 400 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 401 } 402 CHECK_NE(max_allowed_footprint_, 0U); 403 // Create our garbage collectors. 404 for (size_t i = 0; i < 2; ++i) { 405 const bool concurrent = i != 0; 406 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 407 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 408 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 409 } 410 if (kMovingCollector) { 411 // TODO: Clean this up. 412 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 413 semi_space_collector_ = new collector::SemiSpace(this, generational, 414 generational ? "generational" : ""); 415 garbage_collectors_.push_back(semi_space_collector_); 416 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 417 garbage_collectors_.push_back(concurrent_copying_collector_); 418 mark_compact_collector_ = new collector::MarkCompact(this); 419 garbage_collectors_.push_back(mark_compact_collector_); 420 } 421 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr && 422 (is_zygote || separate_non_moving_space || foreground_collector_type_ == kCollectorTypeGSS)) { 423 // Check that there's no gap between the image space and the non moving space so that the 424 // immune region won't break (eg. due to a large object allocated in the gap). This is only 425 // required when we're the zygote or using GSS. 426 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 427 non_moving_space_->GetMemMap()); 428 if (!no_gap) { 429 MemMap::DumpMaps(LOG(ERROR)); 430 LOG(FATAL) << "There's a gap between the image space and the main space"; 431 } 432 } 433 if (running_on_valgrind_) { 434 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 435 } 436 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 437 LOG(INFO) << "Heap() exiting"; 438 } 439} 440 441MemMap* Heap::MapAnonymousPreferredAddress(const char* name, uint8_t* request_begin, 442 size_t capacity, std::string* out_error_str) { 443 while (true) { 444 MemMap* map = MemMap::MapAnonymous(name, request_begin, capacity, 445 PROT_READ | PROT_WRITE, true, out_error_str); 446 if (map != nullptr || request_begin == nullptr) { 447 return map; 448 } 449 // Retry a second time with no specified request begin. 450 request_begin = nullptr; 451 } 452 return nullptr; 453} 454 455space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 456 size_t growth_limit, size_t capacity, 457 const char* name, bool can_move_objects) { 458 space::MallocSpace* malloc_space = nullptr; 459 if (kUseRosAlloc) { 460 // Create rosalloc space. 461 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 462 initial_size, growth_limit, capacity, 463 low_memory_mode_, can_move_objects); 464 } else { 465 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 466 initial_size, growth_limit, capacity, 467 can_move_objects); 468 } 469 if (collector::SemiSpace::kUseRememberedSet) { 470 accounting::RememberedSet* rem_set = 471 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 472 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 473 AddRememberedSet(rem_set); 474 } 475 CHECK(malloc_space != nullptr) << "Failed to create " << name; 476 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 477 return malloc_space; 478} 479 480void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 481 size_t capacity) { 482 // Is background compaction is enabled? 483 bool can_move_objects = IsMovingGc(background_collector_type_) != 484 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 485 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 486 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 487 // from the main space to the zygote space. If background compaction is enabled, always pass in 488 // that we can move objets. 489 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 490 // After the zygote we want this to be false if we don't have background compaction enabled so 491 // that getting primitive array elements is faster. 492 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 493 can_move_objects = !HasZygoteSpace() && foreground_collector_type_ != kCollectorTypeGSS; 494 } 495 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 496 RemoveRememberedSet(main_space_); 497 } 498 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 499 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 500 can_move_objects); 501 SetSpaceAsDefault(main_space_); 502 VLOG(heap) << "Created main space " << main_space_; 503} 504 505void Heap::ChangeAllocator(AllocatorType allocator) { 506 if (current_allocator_ != allocator) { 507 // These two allocators are only used internally and don't have any entrypoints. 508 CHECK_NE(allocator, kAllocatorTypeLOS); 509 CHECK_NE(allocator, kAllocatorTypeNonMoving); 510 current_allocator_ = allocator; 511 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 512 SetQuickAllocEntryPointsAllocator(current_allocator_); 513 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 514 } 515} 516 517void Heap::DisableMovingGc() { 518 if (IsMovingGc(foreground_collector_type_)) { 519 foreground_collector_type_ = kCollectorTypeCMS; 520 } 521 if (IsMovingGc(background_collector_type_)) { 522 background_collector_type_ = foreground_collector_type_; 523 } 524 TransitionCollector(foreground_collector_type_); 525 ThreadList* tl = Runtime::Current()->GetThreadList(); 526 Thread* self = Thread::Current(); 527 ScopedThreadStateChange tsc(self, kSuspended); 528 tl->SuspendAll(); 529 // Something may have caused the transition to fail. 530 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 531 CHECK(main_space_ != nullptr); 532 // The allocation stack may have non movable objects in it. We need to flush it since the GC 533 // can't only handle marking allocation stack objects of one non moving space and one main 534 // space. 535 { 536 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 537 FlushAllocStack(); 538 } 539 main_space_->DisableMovingObjects(); 540 non_moving_space_ = main_space_; 541 CHECK(!non_moving_space_->CanMoveObjects()); 542 } 543 tl->ResumeAll(); 544} 545 546std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 547 if (!IsValidContinuousSpaceObjectAddress(klass)) { 548 return StringPrintf("<non heap address klass %p>", klass); 549 } 550 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 551 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 552 std::string result("["); 553 result += SafeGetClassDescriptor(component_type); 554 return result; 555 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 556 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 557 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 558 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 559 } else { 560 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 561 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 562 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 563 } 564 const DexFile* dex_file = dex_cache->GetDexFile(); 565 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 566 if (class_def_idx == DexFile::kDexNoIndex16) { 567 return "<class def not found>"; 568 } 569 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 570 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 571 return dex_file->GetTypeDescriptor(type_id); 572 } 573} 574 575std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 576 if (obj == nullptr) { 577 return "null"; 578 } 579 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 580 if (klass == nullptr) { 581 return "(class=null)"; 582 } 583 std::string result(SafeGetClassDescriptor(klass)); 584 if (obj->IsClass()) { 585 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 586 } 587 return result; 588} 589 590void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 591 if (obj == nullptr) { 592 stream << "(obj=null)"; 593 return; 594 } 595 if (IsAligned<kObjectAlignment>(obj)) { 596 space::Space* space = nullptr; 597 // Don't use find space since it only finds spaces which actually contain objects instead of 598 // spaces which may contain objects (e.g. cleared bump pointer spaces). 599 for (const auto& cur_space : continuous_spaces_) { 600 if (cur_space->HasAddress(obj)) { 601 space = cur_space; 602 break; 603 } 604 } 605 // Unprotect all the spaces. 606 for (const auto& con_space : continuous_spaces_) { 607 mprotect(con_space->Begin(), con_space->Capacity(), PROT_READ | PROT_WRITE); 608 } 609 stream << "Object " << obj; 610 if (space != nullptr) { 611 stream << " in space " << *space; 612 } 613 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 614 stream << "\nclass=" << klass; 615 if (klass != nullptr) { 616 stream << " type= " << SafePrettyTypeOf(obj); 617 } 618 // Re-protect the address we faulted on. 619 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 620 } 621} 622 623bool Heap::IsCompilingBoot() const { 624 if (!Runtime::Current()->IsCompiler()) { 625 return false; 626 } 627 for (const auto& space : continuous_spaces_) { 628 if (space->IsImageSpace() || space->IsZygoteSpace()) { 629 return false; 630 } 631 } 632 return true; 633} 634 635bool Heap::HasImageSpace() const { 636 for (const auto& space : continuous_spaces_) { 637 if (space->IsImageSpace()) { 638 return true; 639 } 640 } 641 return false; 642} 643 644void Heap::IncrementDisableMovingGC(Thread* self) { 645 // Need to do this holding the lock to prevent races where the GC is about to run / running when 646 // we attempt to disable it. 647 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 648 MutexLock mu(self, *gc_complete_lock_); 649 ++disable_moving_gc_count_; 650 if (IsMovingGc(collector_type_running_)) { 651 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 652 } 653} 654 655void Heap::DecrementDisableMovingGC(Thread* self) { 656 MutexLock mu(self, *gc_complete_lock_); 657 CHECK_GE(disable_moving_gc_count_, 0U); 658 --disable_moving_gc_count_; 659} 660 661void Heap::UpdateProcessState(ProcessState process_state) { 662 if (process_state_ != process_state) { 663 process_state_ = process_state; 664 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 665 // Start at index 1 to avoid "is always false" warning. 666 // Have iteration 1 always transition the collector. 667 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 668 ? foreground_collector_type_ : background_collector_type_); 669 usleep(kCollectorTransitionStressWait); 670 } 671 if (process_state_ == kProcessStateJankPerceptible) { 672 // Transition back to foreground right away to prevent jank. 673 RequestCollectorTransition(foreground_collector_type_, 0); 674 } else { 675 // Don't delay for debug builds since we may want to stress test the GC. 676 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 677 // special handling which does a homogenous space compaction once but then doesn't transition 678 // the collector. 679 RequestCollectorTransition(background_collector_type_, 680 kIsDebugBuild ? 0 : kCollectorTransitionWait); 681 } 682 } 683} 684 685void Heap::CreateThreadPool() { 686 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 687 if (num_threads != 0) { 688 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 689 } 690} 691 692void Heap::VisitObjects(ObjectCallback callback, void* arg) { 693 // GCs can move objects, so don't allow this. 694 ScopedAssertNoThreadSuspension ants(Thread::Current(), "Visiting objects"); 695 if (bump_pointer_space_ != nullptr) { 696 // Visit objects in bump pointer space. 697 bump_pointer_space_->Walk(callback, arg); 698 } 699 // TODO: Switch to standard begin and end to use ranged a based loop. 700 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 701 it < end; ++it) { 702 mirror::Object* obj = *it; 703 if (obj != nullptr && obj->GetClass() != nullptr) { 704 // Avoid the race condition caused by the object not yet being written into the allocation 705 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 706 // there can be nulls on the allocation stack. 707 callback(obj, arg); 708 } 709 } 710 GetLiveBitmap()->Walk(callback, arg); 711} 712 713void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 714 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 715 space::ContinuousSpace* space2 = non_moving_space_; 716 // TODO: Generalize this to n bitmaps? 717 CHECK(space1 != nullptr); 718 CHECK(space2 != nullptr); 719 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 720 (large_object_space_ != nullptr ? large_object_space_->GetLiveBitmap() : nullptr), 721 stack); 722} 723 724void Heap::DeleteThreadPool() { 725 thread_pool_.reset(nullptr); 726} 727 728void Heap::AddSpace(space::Space* space) { 729 CHECK(space != nullptr); 730 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 731 if (space->IsContinuousSpace()) { 732 DCHECK(!space->IsDiscontinuousSpace()); 733 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 734 // Continuous spaces don't necessarily have bitmaps. 735 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 736 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 737 if (live_bitmap != nullptr) { 738 CHECK(mark_bitmap != nullptr); 739 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 740 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 741 } 742 continuous_spaces_.push_back(continuous_space); 743 // Ensure that spaces remain sorted in increasing order of start address. 744 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 745 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 746 return a->Begin() < b->Begin(); 747 }); 748 } else { 749 CHECK(space->IsDiscontinuousSpace()); 750 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 751 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 752 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 753 discontinuous_spaces_.push_back(discontinuous_space); 754 } 755 if (space->IsAllocSpace()) { 756 alloc_spaces_.push_back(space->AsAllocSpace()); 757 } 758} 759 760void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 761 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 762 if (continuous_space->IsDlMallocSpace()) { 763 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 764 } else if (continuous_space->IsRosAllocSpace()) { 765 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 766 } 767} 768 769void Heap::RemoveSpace(space::Space* space) { 770 DCHECK(space != nullptr); 771 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 772 if (space->IsContinuousSpace()) { 773 DCHECK(!space->IsDiscontinuousSpace()); 774 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 775 // Continuous spaces don't necessarily have bitmaps. 776 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 777 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 778 if (live_bitmap != nullptr) { 779 DCHECK(mark_bitmap != nullptr); 780 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 781 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 782 } 783 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 784 DCHECK(it != continuous_spaces_.end()); 785 continuous_spaces_.erase(it); 786 } else { 787 DCHECK(space->IsDiscontinuousSpace()); 788 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 789 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 790 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 791 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 792 discontinuous_space); 793 DCHECK(it != discontinuous_spaces_.end()); 794 discontinuous_spaces_.erase(it); 795 } 796 if (space->IsAllocSpace()) { 797 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 798 DCHECK(it != alloc_spaces_.end()); 799 alloc_spaces_.erase(it); 800 } 801} 802 803void Heap::DumpGcPerformanceInfo(std::ostream& os) { 804 // Dump cumulative timings. 805 os << "Dumping cumulative Gc timings\n"; 806 uint64_t total_duration = 0; 807 // Dump cumulative loggers for each GC type. 808 uint64_t total_paused_time = 0; 809 for (auto& collector : garbage_collectors_) { 810 total_duration += collector->GetCumulativeTimings().GetTotalNs(); 811 total_paused_time += collector->GetTotalPausedTimeNs(); 812 collector->DumpPerformanceInfo(os); 813 collector->ResetMeasurements(); 814 } 815 uint64_t allocation_time = 816 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 817 if (total_duration != 0) { 818 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 819 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 820 os << "Mean GC size throughput: " 821 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 822 os << "Mean GC object throughput: " 823 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 824 } 825 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 826 os << "Total number of allocations " << total_objects_allocated << "\n"; 827 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 828 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 829 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 830 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 831 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 832 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 833 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 834 if (kMeasureAllocationTime) { 835 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 836 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 837 << "\n"; 838 } 839 if (HasZygoteSpace()) { 840 os << "Zygote space size " << PrettySize(zygote_space_->Size()) << "\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 BaseMutex::DumpAll(os); 845} 846 847Heap::~Heap() { 848 VLOG(heap) << "Starting ~Heap()"; 849 STLDeleteElements(&garbage_collectors_); 850 // If we don't reset then the mark stack complains in its destructor. 851 allocation_stack_->Reset(); 852 live_stack_->Reset(); 853 STLDeleteValues(&mod_union_tables_); 854 STLDeleteValues(&remembered_sets_); 855 STLDeleteElements(&continuous_spaces_); 856 STLDeleteElements(&discontinuous_spaces_); 857 delete gc_complete_lock_; 858 delete heap_trim_request_lock_; 859 VLOG(heap) << "Finished ~Heap()"; 860} 861 862space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 863 bool fail_ok) const { 864 for (const auto& space : continuous_spaces_) { 865 if (space->Contains(obj)) { 866 return space; 867 } 868 } 869 if (!fail_ok) { 870 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 871 } 872 return NULL; 873} 874 875space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 876 bool fail_ok) const { 877 for (const auto& space : discontinuous_spaces_) { 878 if (space->Contains(obj)) { 879 return space; 880 } 881 } 882 if (!fail_ok) { 883 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 884 } 885 return NULL; 886} 887 888space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 889 space::Space* result = FindContinuousSpaceFromObject(obj, true); 890 if (result != NULL) { 891 return result; 892 } 893 return FindDiscontinuousSpaceFromObject(obj, fail_ok); 894} 895 896space::ImageSpace* Heap::GetImageSpace() const { 897 for (const auto& space : continuous_spaces_) { 898 if (space->IsImageSpace()) { 899 return space->AsImageSpace(); 900 } 901 } 902 return NULL; 903} 904 905void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 906 std::ostringstream oss; 907 size_t total_bytes_free = GetFreeMemory(); 908 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 909 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 910 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 911 if (total_bytes_free >= byte_count) { 912 space::AllocSpace* space = nullptr; 913 if (allocator_type == kAllocatorTypeNonMoving) { 914 space = non_moving_space_; 915 } else if (allocator_type == kAllocatorTypeRosAlloc || 916 allocator_type == kAllocatorTypeDlMalloc) { 917 space = main_space_; 918 } else if (allocator_type == kAllocatorTypeBumpPointer || 919 allocator_type == kAllocatorTypeTLAB) { 920 space = bump_pointer_space_; 921 } 922 if (space != nullptr) { 923 space->LogFragmentationAllocFailure(oss, byte_count); 924 } 925 } 926 self->ThrowOutOfMemoryError(oss.str().c_str()); 927} 928 929void Heap::DoPendingTransitionOrTrim() { 930 Thread* self = Thread::Current(); 931 CollectorType desired_collector_type; 932 // Wait until we reach the desired transition time. 933 while (true) { 934 uint64_t wait_time; 935 { 936 MutexLock mu(self, *heap_trim_request_lock_); 937 desired_collector_type = desired_collector_type_; 938 uint64_t current_time = NanoTime(); 939 if (current_time >= heap_transition_or_trim_target_time_) { 940 break; 941 } 942 wait_time = heap_transition_or_trim_target_time_ - current_time; 943 } 944 ScopedThreadStateChange tsc(self, kSleeping); 945 usleep(wait_time / 1000); // Usleep takes microseconds. 946 } 947 // Launch homogeneous space compaction if it is desired. 948 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 949 if (!CareAboutPauseTimes()) { 950 PerformHomogeneousSpaceCompact(); 951 } 952 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 953 desired_collector_type = collector_type_; 954 return; 955 } 956 // Transition the collector if the desired collector type is not the same as the current 957 // collector type. 958 TransitionCollector(desired_collector_type); 959 if (!CareAboutPauseTimes()) { 960 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 961 // about pauses. 962 Runtime* runtime = Runtime::Current(); 963 runtime->GetThreadList()->SuspendAll(); 964 uint64_t start_time = NanoTime(); 965 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 966 VLOG(heap) << "Deflating " << count << " monitors took " 967 << PrettyDuration(NanoTime() - start_time); 968 runtime->GetThreadList()->ResumeAll(); 969 } 970 // Do a heap trim if it is needed. 971 Trim(); 972} 973 974void Heap::Trim() { 975 Thread* self = Thread::Current(); 976 { 977 MutexLock mu(self, *heap_trim_request_lock_); 978 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 979 return; 980 } 981 last_trim_time_ = NanoTime(); 982 heap_trim_request_pending_ = false; 983 } 984 { 985 // Need to do this before acquiring the locks since we don't want to get suspended while 986 // holding any locks. 987 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 988 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 989 // trimming. 990 MutexLock mu(self, *gc_complete_lock_); 991 // Ensure there is only one GC at a time. 992 WaitForGcToCompleteLocked(kGcCauseTrim, self); 993 collector_type_running_ = kCollectorTypeHeapTrim; 994 } 995 uint64_t start_ns = NanoTime(); 996 // Trim the managed spaces. 997 uint64_t total_alloc_space_allocated = 0; 998 uint64_t total_alloc_space_size = 0; 999 uint64_t managed_reclaimed = 0; 1000 for (const auto& space : continuous_spaces_) { 1001 if (space->IsMallocSpace()) { 1002 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 1003 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 1004 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 1005 // for a long period of time. 1006 managed_reclaimed += malloc_space->Trim(); 1007 } 1008 total_alloc_space_size += malloc_space->Size(); 1009 } 1010 } 1011 total_alloc_space_allocated = GetBytesAllocated(); 1012 if (large_object_space_ != nullptr) { 1013 total_alloc_space_allocated -= large_object_space_->GetBytesAllocated(); 1014 } 1015 if (bump_pointer_space_ != nullptr) { 1016 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1017 } 1018 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1019 static_cast<float>(total_alloc_space_size); 1020 uint64_t gc_heap_end_ns = NanoTime(); 1021 // We never move things in the native heap, so we can finish the GC at this point. 1022 FinishGC(self, collector::kGcTypeNone); 1023 size_t native_reclaimed = 0; 1024 1025#ifdef HAVE_ANDROID_OS 1026 // Only trim the native heap if we don't care about pauses. 1027 if (!CareAboutPauseTimes()) { 1028#if defined(USE_DLMALLOC) 1029 // Trim the native heap. 1030 dlmalloc_trim(0); 1031 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1032#elif defined(USE_JEMALLOC) 1033 // Jemalloc does it's own internal trimming. 1034#else 1035 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1036#endif 1037 } 1038#endif // HAVE_ANDROID_OS 1039 uint64_t end_ns = NanoTime(); 1040 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1041 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1042 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1043 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1044 << "%."; 1045} 1046 1047bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1048 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1049 // taking the lock. 1050 if (obj == nullptr) { 1051 return true; 1052 } 1053 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1054} 1055 1056bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1057 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1058} 1059 1060bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1061 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1062 return false; 1063 } 1064 for (const auto& space : continuous_spaces_) { 1065 if (space->HasAddress(obj)) { 1066 return true; 1067 } 1068 } 1069 return false; 1070} 1071 1072bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1073 bool search_live_stack, bool sorted) { 1074 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1075 return false; 1076 } 1077 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1078 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1079 if (obj == klass) { 1080 // This case happens for java.lang.Class. 1081 return true; 1082 } 1083 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1084 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1085 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1086 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1087 return temp_space_->Contains(obj); 1088 } 1089 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1090 space::DiscontinuousSpace* d_space = nullptr; 1091 if (c_space != nullptr) { 1092 if (c_space->GetLiveBitmap()->Test(obj)) { 1093 return true; 1094 } 1095 } else { 1096 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1097 if (d_space != nullptr) { 1098 if (d_space->GetLiveBitmap()->Test(obj)) { 1099 return true; 1100 } 1101 } 1102 } 1103 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1104 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1105 if (i > 0) { 1106 NanoSleep(MsToNs(10)); 1107 } 1108 if (search_allocation_stack) { 1109 if (sorted) { 1110 if (allocation_stack_->ContainsSorted(obj)) { 1111 return true; 1112 } 1113 } else if (allocation_stack_->Contains(obj)) { 1114 return true; 1115 } 1116 } 1117 1118 if (search_live_stack) { 1119 if (sorted) { 1120 if (live_stack_->ContainsSorted(obj)) { 1121 return true; 1122 } 1123 } else if (live_stack_->Contains(obj)) { 1124 return true; 1125 } 1126 } 1127 } 1128 // We need to check the bitmaps again since there is a race where we mark something as live and 1129 // then clear the stack containing it. 1130 if (c_space != nullptr) { 1131 if (c_space->GetLiveBitmap()->Test(obj)) { 1132 return true; 1133 } 1134 } else { 1135 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1136 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1137 return true; 1138 } 1139 } 1140 return false; 1141} 1142 1143std::string Heap::DumpSpaces() const { 1144 std::ostringstream oss; 1145 DumpSpaces(oss); 1146 return oss.str(); 1147} 1148 1149void Heap::DumpSpaces(std::ostream& stream) const { 1150 for (const auto& space : continuous_spaces_) { 1151 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1152 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1153 stream << space << " " << *space << "\n"; 1154 if (live_bitmap != nullptr) { 1155 stream << live_bitmap << " " << *live_bitmap << "\n"; 1156 } 1157 if (mark_bitmap != nullptr) { 1158 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1159 } 1160 } 1161 for (const auto& space : discontinuous_spaces_) { 1162 stream << space << " " << *space << "\n"; 1163 } 1164} 1165 1166void Heap::VerifyObjectBody(mirror::Object* obj) { 1167 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1168 return; 1169 } 1170 1171 // Ignore early dawn of the universe verifications. 1172 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1173 return; 1174 } 1175 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1176 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1177 CHECK(c != nullptr) << "Null class in object " << obj; 1178 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1179 CHECK(VerifyClassClass(c)); 1180 1181 if (verify_object_mode_ > kVerifyObjectModeFast) { 1182 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1183 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1184 } 1185} 1186 1187void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1188 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1189} 1190 1191void Heap::VerifyHeap() { 1192 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1193 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1194} 1195 1196void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1197 // Use signed comparison since freed bytes can be negative when background compaction foreground 1198 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1199 // free list backed space typically increasing memory footprint due to padding and binning. 1200 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1201 // Note: This relies on 2s complement for handling negative freed_bytes. 1202 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1203 if (Runtime::Current()->HasStatsEnabled()) { 1204 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1205 thread_stats->freed_objects += freed_objects; 1206 thread_stats->freed_bytes += freed_bytes; 1207 // TODO: Do this concurrently. 1208 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1209 global_stats->freed_objects += freed_objects; 1210 global_stats->freed_bytes += freed_bytes; 1211 } 1212} 1213 1214space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1215 for (const auto& space : continuous_spaces_) { 1216 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1217 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1218 return space->AsContinuousSpace()->AsRosAllocSpace(); 1219 } 1220 } 1221 } 1222 return nullptr; 1223} 1224 1225mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1226 size_t alloc_size, size_t* bytes_allocated, 1227 size_t* usable_size, 1228 mirror::Class** klass) { 1229 bool was_default_allocator = allocator == GetCurrentAllocator(); 1230 // Make sure there is no pending exception since we may need to throw an OOME. 1231 self->AssertNoPendingException(); 1232 DCHECK(klass != nullptr); 1233 StackHandleScope<1> hs(self); 1234 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1235 klass = nullptr; // Invalidate for safety. 1236 // The allocation failed. If the GC is running, block until it completes, and then retry the 1237 // allocation. 1238 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1239 if (last_gc != collector::kGcTypeNone) { 1240 // If we were the default allocator but the allocator changed while we were suspended, 1241 // abort the allocation. 1242 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1243 return nullptr; 1244 } 1245 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1246 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1247 usable_size); 1248 if (ptr != nullptr) { 1249 return ptr; 1250 } 1251 } 1252 1253 collector::GcType tried_type = next_gc_type_; 1254 const bool gc_ran = 1255 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1256 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1257 return nullptr; 1258 } 1259 if (gc_ran) { 1260 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1261 usable_size); 1262 if (ptr != nullptr) { 1263 return ptr; 1264 } 1265 } 1266 1267 // Loop through our different Gc types and try to Gc until we get enough free memory. 1268 for (collector::GcType gc_type : gc_plan_) { 1269 if (gc_type == tried_type) { 1270 continue; 1271 } 1272 // Attempt to run the collector, if we succeed, re-try the allocation. 1273 const bool plan_gc_ran = 1274 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1275 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1276 return nullptr; 1277 } 1278 if (plan_gc_ran) { 1279 // Did we free sufficient memory for the allocation to succeed? 1280 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1281 usable_size); 1282 if (ptr != nullptr) { 1283 return ptr; 1284 } 1285 } 1286 } 1287 // Allocations have failed after GCs; this is an exceptional state. 1288 // Try harder, growing the heap if necessary. 1289 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1290 usable_size); 1291 if (ptr != nullptr) { 1292 return ptr; 1293 } 1294 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1295 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1296 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1297 // OOME. 1298 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1299 << " allocation"; 1300 // TODO: Run finalization, but this may cause more allocations to occur. 1301 // We don't need a WaitForGcToComplete here either. 1302 DCHECK(!gc_plan_.empty()); 1303 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1304 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1305 return nullptr; 1306 } 1307 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1308 if (ptr == nullptr) { 1309 const uint64_t current_time = NanoTime(); 1310 switch (allocator) { 1311 case kAllocatorTypeRosAlloc: 1312 // Fall-through. 1313 case kAllocatorTypeDlMalloc: { 1314 if (use_homogeneous_space_compaction_for_oom_ && 1315 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1316 min_interval_homogeneous_space_compaction_by_oom_) { 1317 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1318 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1319 switch (result) { 1320 case HomogeneousSpaceCompactResult::kSuccess: 1321 // If the allocation succeeded, we delayed an oom. 1322 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1323 usable_size); 1324 if (ptr != nullptr) { 1325 count_delayed_oom_++; 1326 } 1327 break; 1328 case HomogeneousSpaceCompactResult::kErrorReject: 1329 // Reject due to disabled moving GC. 1330 break; 1331 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1332 // Throw OOM by default. 1333 break; 1334 default: { 1335 UNIMPLEMENTED(FATAL) << "homogeneous space compaction result: " 1336 << static_cast<size_t>(result); 1337 UNREACHABLE(); 1338 } 1339 } 1340 // Always print that we ran homogeneous space compation since this can cause jank. 1341 VLOG(heap) << "Ran heap homogeneous space compaction, " 1342 << " requested defragmentation " 1343 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1344 << " performed defragmentation " 1345 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1346 << " ignored homogeneous space compaction " 1347 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1348 << " delayed count = " 1349 << count_delayed_oom_.LoadSequentiallyConsistent(); 1350 } 1351 break; 1352 } 1353 case kAllocatorTypeNonMoving: { 1354 // Try to transition the heap if the allocation failure was due to the space being full. 1355 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1356 // If we aren't out of memory then the OOM was probably from the non moving space being 1357 // full. Attempt to disable compaction and turn the main space into a non moving space. 1358 DisableMovingGc(); 1359 // If we are still a moving GC then something must have caused the transition to fail. 1360 if (IsMovingGc(collector_type_)) { 1361 MutexLock mu(self, *gc_complete_lock_); 1362 // If we couldn't disable moving GC, just throw OOME and return null. 1363 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1364 << disable_moving_gc_count_; 1365 } else { 1366 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1367 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1368 usable_size); 1369 } 1370 } 1371 break; 1372 } 1373 default: { 1374 // Do nothing for others allocators. 1375 } 1376 } 1377 } 1378 // If the allocation hasn't succeeded by this point, throw an OOM error. 1379 if (ptr == nullptr) { 1380 ThrowOutOfMemoryError(self, alloc_size, allocator); 1381 } 1382 return ptr; 1383} 1384 1385void Heap::SetTargetHeapUtilization(float target) { 1386 DCHECK_GT(target, 0.0f); // asserted in Java code 1387 DCHECK_LT(target, 1.0f); 1388 target_utilization_ = target; 1389} 1390 1391size_t Heap::GetObjectsAllocated() const { 1392 size_t total = 0; 1393 for (space::AllocSpace* space : alloc_spaces_) { 1394 total += space->GetObjectsAllocated(); 1395 } 1396 return total; 1397} 1398 1399uint64_t Heap::GetObjectsAllocatedEver() const { 1400 return GetObjectsFreedEver() + GetObjectsAllocated(); 1401} 1402 1403uint64_t Heap::GetBytesAllocatedEver() const { 1404 return GetBytesFreedEver() + GetBytesAllocated(); 1405} 1406 1407class InstanceCounter { 1408 public: 1409 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1410 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1411 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1412 } 1413 static void Callback(mirror::Object* obj, void* arg) 1414 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1415 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1416 mirror::Class* instance_class = obj->GetClass(); 1417 CHECK(instance_class != nullptr); 1418 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1419 if (instance_counter->use_is_assignable_from_) { 1420 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1421 ++instance_counter->counts_[i]; 1422 } 1423 } else if (instance_class == instance_counter->classes_[i]) { 1424 ++instance_counter->counts_[i]; 1425 } 1426 } 1427 } 1428 1429 private: 1430 const std::vector<mirror::Class*>& classes_; 1431 bool use_is_assignable_from_; 1432 uint64_t* const counts_; 1433 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1434}; 1435 1436void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1437 uint64_t* counts) { 1438 // Can't do any GC in this function since this may move classes. 1439 ScopedAssertNoThreadSuspension ants(Thread::Current(), "CountInstances"); 1440 InstanceCounter counter(classes, use_is_assignable_from, counts); 1441 ReaderMutexLock mu(ants.Self(), *Locks::heap_bitmap_lock_); 1442 VisitObjects(InstanceCounter::Callback, &counter); 1443} 1444 1445class InstanceCollector { 1446 public: 1447 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1448 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1449 : class_(c), max_count_(max_count), instances_(instances) { 1450 } 1451 static void Callback(mirror::Object* obj, void* arg) 1452 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1453 DCHECK(arg != nullptr); 1454 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1455 if (obj->GetClass() == instance_collector->class_) { 1456 if (instance_collector->max_count_ == 0 || 1457 instance_collector->instances_.size() < instance_collector->max_count_) { 1458 instance_collector->instances_.push_back(obj); 1459 } 1460 } 1461 } 1462 1463 private: 1464 const mirror::Class* const class_; 1465 const uint32_t max_count_; 1466 std::vector<mirror::Object*>& instances_; 1467 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1468}; 1469 1470void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1471 std::vector<mirror::Object*>& instances) { 1472 // Can't do any GC in this function since this may move classes. 1473 ScopedAssertNoThreadSuspension ants(Thread::Current(), "GetInstances"); 1474 InstanceCollector collector(c, max_count, instances); 1475 ReaderMutexLock mu(ants.Self(), *Locks::heap_bitmap_lock_); 1476 VisitObjects(&InstanceCollector::Callback, &collector); 1477} 1478 1479class ReferringObjectsFinder { 1480 public: 1481 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1482 std::vector<mirror::Object*>& referring_objects) 1483 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1484 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1485 } 1486 1487 static void Callback(mirror::Object* obj, void* arg) 1488 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1489 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1490 } 1491 1492 // For bitmap Visit. 1493 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1494 // annotalysis on visitors. 1495 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1496 o->VisitReferences<true>(*this, VoidFunctor()); 1497 } 1498 1499 // For Object::VisitReferences. 1500 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1501 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1502 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1503 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1504 referring_objects_.push_back(obj); 1505 } 1506 } 1507 1508 private: 1509 const mirror::Object* const object_; 1510 const uint32_t max_count_; 1511 std::vector<mirror::Object*>& referring_objects_; 1512 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1513}; 1514 1515void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1516 std::vector<mirror::Object*>& referring_objects) { 1517 // Can't do any GC in this function since this may move the object o. 1518 ScopedAssertNoThreadSuspension ants(Thread::Current(), "GetReferringObjects"); 1519 ReferringObjectsFinder finder(o, max_count, referring_objects); 1520 ReaderMutexLock mu(ants.Self(), *Locks::heap_bitmap_lock_); 1521 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1522} 1523 1524void Heap::CollectGarbage(bool clear_soft_references) { 1525 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1526 // last GC will not have necessarily been cleared. 1527 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1528} 1529 1530HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1531 Thread* self = Thread::Current(); 1532 // Inc requested homogeneous space compaction. 1533 count_requested_homogeneous_space_compaction_++; 1534 // Store performed homogeneous space compaction at a new request arrival. 1535 ThreadList* tl = Runtime::Current()->GetThreadList(); 1536 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1537 Locks::mutator_lock_->AssertNotHeld(self); 1538 { 1539 ScopedThreadStateChange tsc2(self, kWaitingForGcToComplete); 1540 MutexLock mu(self, *gc_complete_lock_); 1541 // Ensure there is only one GC at a time. 1542 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1543 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1544 // is non zero. 1545 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1546 // exit. 1547 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1548 !main_space_->CanMoveObjects()) { 1549 return HomogeneousSpaceCompactResult::kErrorReject; 1550 } 1551 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1552 } 1553 if (Runtime::Current()->IsShuttingDown(self)) { 1554 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1555 // cause objects to get finalized. 1556 FinishGC(self, collector::kGcTypeNone); 1557 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1558 } 1559 // Suspend all threads. 1560 tl->SuspendAll(); 1561 uint64_t start_time = NanoTime(); 1562 // Launch compaction. 1563 space::MallocSpace* to_space = main_space_backup_.release(); 1564 space::MallocSpace* from_space = main_space_; 1565 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1566 const uint64_t space_size_before_compaction = from_space->Size(); 1567 AddSpace(to_space); 1568 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1569 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1570 from_space->GetMemMap()->Protect(PROT_READ); 1571 const uint64_t space_size_after_compaction = to_space->Size(); 1572 main_space_ = to_space; 1573 main_space_backup_.reset(from_space); 1574 RemoveSpace(from_space); 1575 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1576 // Update performed homogeneous space compaction count. 1577 count_performed_homogeneous_space_compaction_++; 1578 // Print statics log and resume all threads. 1579 uint64_t duration = NanoTime() - start_time; 1580 VLOG(heap) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1581 << PrettySize(space_size_before_compaction) << " -> " 1582 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1583 << std::fixed << static_cast<double>(space_size_after_compaction) / 1584 static_cast<double>(space_size_before_compaction); 1585 tl->ResumeAll(); 1586 // Finish GC. 1587 reference_processor_.EnqueueClearedReferences(self); 1588 GrowForUtilization(semi_space_collector_); 1589 FinishGC(self, collector::kGcTypeFull); 1590 return HomogeneousSpaceCompactResult::kSuccess; 1591} 1592 1593 1594void Heap::TransitionCollector(CollectorType collector_type) { 1595 if (collector_type == collector_type_) { 1596 return; 1597 } 1598 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1599 << " -> " << static_cast<int>(collector_type); 1600 uint64_t start_time = NanoTime(); 1601 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1602 Runtime* const runtime = Runtime::Current(); 1603 ThreadList* const tl = runtime->GetThreadList(); 1604 Thread* const self = Thread::Current(); 1605 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1606 Locks::mutator_lock_->AssertNotHeld(self); 1607 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1608 // compacting_gc_disable_count_, this should rarely occurs). 1609 for (;;) { 1610 { 1611 ScopedThreadStateChange tsc2(self, kWaitingForGcToComplete); 1612 MutexLock mu(self, *gc_complete_lock_); 1613 // Ensure there is only one GC at a time. 1614 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1615 // Currently we only need a heap transition if we switch from a moving collector to a 1616 // non-moving one, or visa versa. 1617 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1618 // If someone else beat us to it and changed the collector before we could, exit. 1619 // This is safe to do before the suspend all since we set the collector_type_running_ before 1620 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1621 // then it would get blocked on WaitForGcToCompleteLocked. 1622 if (collector_type == collector_type_) { 1623 return; 1624 } 1625 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1626 if (!copying_transition || disable_moving_gc_count_ == 0) { 1627 // TODO: Not hard code in semi-space collector? 1628 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1629 break; 1630 } 1631 } 1632 usleep(1000); 1633 } 1634 if (runtime->IsShuttingDown(self)) { 1635 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1636 // cause objects to get finalized. 1637 FinishGC(self, collector::kGcTypeNone); 1638 return; 1639 } 1640 tl->SuspendAll(); 1641 switch (collector_type) { 1642 case kCollectorTypeSS: { 1643 if (!IsMovingGc(collector_type_)) { 1644 // Create the bump pointer space from the backup space. 1645 CHECK(main_space_backup_ != nullptr); 1646 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1647 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1648 // pointer space last transition it will be protected. 1649 CHECK(mem_map != nullptr); 1650 mem_map->Protect(PROT_READ | PROT_WRITE); 1651 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1652 mem_map.release()); 1653 AddSpace(bump_pointer_space_); 1654 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1655 // Use the now empty main space mem map for the bump pointer temp space. 1656 mem_map.reset(main_space_->ReleaseMemMap()); 1657 // Unset the pointers just in case. 1658 if (dlmalloc_space_ == main_space_) { 1659 dlmalloc_space_ = nullptr; 1660 } else if (rosalloc_space_ == main_space_) { 1661 rosalloc_space_ = nullptr; 1662 } 1663 // Remove the main space so that we don't try to trim it, this doens't work for debug 1664 // builds since RosAlloc attempts to read the magic number from a protected page. 1665 RemoveSpace(main_space_); 1666 RemoveRememberedSet(main_space_); 1667 delete main_space_; // Delete the space since it has been removed. 1668 main_space_ = nullptr; 1669 RemoveRememberedSet(main_space_backup_.get()); 1670 main_space_backup_.reset(nullptr); // Deletes the space. 1671 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1672 mem_map.release()); 1673 AddSpace(temp_space_); 1674 } 1675 break; 1676 } 1677 case kCollectorTypeMS: 1678 // Fall through. 1679 case kCollectorTypeCMS: { 1680 if (IsMovingGc(collector_type_)) { 1681 CHECK(temp_space_ != nullptr); 1682 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1683 RemoveSpace(temp_space_); 1684 temp_space_ = nullptr; 1685 mem_map->Protect(PROT_READ | PROT_WRITE); 1686 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1687 mem_map->Size()); 1688 mem_map.release(); 1689 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1690 AddSpace(main_space_); 1691 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1692 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1693 RemoveSpace(bump_pointer_space_); 1694 bump_pointer_space_ = nullptr; 1695 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1696 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1697 if (kIsDebugBuild && kUseRosAlloc) { 1698 mem_map->Protect(PROT_READ | PROT_WRITE); 1699 } 1700 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1701 mem_map->Size(), mem_map->Size(), 1702 name, true)); 1703 if (kIsDebugBuild && kUseRosAlloc) { 1704 mem_map->Protect(PROT_NONE); 1705 } 1706 mem_map.release(); 1707 } 1708 break; 1709 } 1710 default: { 1711 LOG(FATAL) << "Attempted to transition to invalid collector type " 1712 << static_cast<size_t>(collector_type); 1713 break; 1714 } 1715 } 1716 ChangeCollector(collector_type); 1717 tl->ResumeAll(); 1718 // Can't call into java code with all threads suspended. 1719 reference_processor_.EnqueueClearedReferences(self); 1720 uint64_t duration = NanoTime() - start_time; 1721 GrowForUtilization(semi_space_collector_); 1722 FinishGC(self, collector::kGcTypeFull); 1723 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1724 int32_t delta_allocated = before_allocated - after_allocated; 1725 std::string saved_str; 1726 if (delta_allocated >= 0) { 1727 saved_str = " saved at least " + PrettySize(delta_allocated); 1728 } else { 1729 saved_str = " expanded " + PrettySize(-delta_allocated); 1730 } 1731 VLOG(heap) << "Heap transition to " << process_state_ << " took " 1732 << PrettyDuration(duration) << saved_str; 1733} 1734 1735void Heap::ChangeCollector(CollectorType collector_type) { 1736 // TODO: Only do this with all mutators suspended to avoid races. 1737 if (collector_type != collector_type_) { 1738 if (collector_type == kCollectorTypeMC) { 1739 // Don't allow mark compact unless support is compiled in. 1740 CHECK(kMarkCompactSupport); 1741 } 1742 collector_type_ = collector_type; 1743 gc_plan_.clear(); 1744 switch (collector_type_) { 1745 case kCollectorTypeCC: // Fall-through. 1746 case kCollectorTypeMC: // Fall-through. 1747 case kCollectorTypeSS: // Fall-through. 1748 case kCollectorTypeGSS: { 1749 gc_plan_.push_back(collector::kGcTypeFull); 1750 if (use_tlab_) { 1751 ChangeAllocator(kAllocatorTypeTLAB); 1752 } else { 1753 ChangeAllocator(kAllocatorTypeBumpPointer); 1754 } 1755 break; 1756 } 1757 case kCollectorTypeMS: { 1758 gc_plan_.push_back(collector::kGcTypeSticky); 1759 gc_plan_.push_back(collector::kGcTypePartial); 1760 gc_plan_.push_back(collector::kGcTypeFull); 1761 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1762 break; 1763 } 1764 case kCollectorTypeCMS: { 1765 gc_plan_.push_back(collector::kGcTypeSticky); 1766 gc_plan_.push_back(collector::kGcTypePartial); 1767 gc_plan_.push_back(collector::kGcTypeFull); 1768 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1769 break; 1770 } 1771 default: { 1772 UNIMPLEMENTED(FATAL); 1773 UNREACHABLE(); 1774 } 1775 } 1776 if (IsGcConcurrent()) { 1777 concurrent_start_bytes_ = 1778 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1779 } else { 1780 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1781 } 1782 } 1783} 1784 1785// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1786class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1787 public: 1788 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1789 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1790 } 1791 1792 void BuildBins(space::ContinuousSpace* space) { 1793 bin_live_bitmap_ = space->GetLiveBitmap(); 1794 bin_mark_bitmap_ = space->GetMarkBitmap(); 1795 BinContext context; 1796 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1797 context.collector_ = this; 1798 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1799 // Note: This requires traversing the space in increasing order of object addresses. 1800 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1801 // Add the last bin which spans after the last object to the end of the space. 1802 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1803 } 1804 1805 private: 1806 struct BinContext { 1807 uintptr_t prev_; // The end of the previous object. 1808 ZygoteCompactingCollector* collector_; 1809 }; 1810 // Maps from bin sizes to locations. 1811 std::multimap<size_t, uintptr_t> bins_; 1812 // Live bitmap of the space which contains the bins. 1813 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1814 // Mark bitmap of the space which contains the bins. 1815 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1816 1817 static void Callback(mirror::Object* obj, void* arg) 1818 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1819 DCHECK(arg != nullptr); 1820 BinContext* context = reinterpret_cast<BinContext*>(arg); 1821 ZygoteCompactingCollector* collector = context->collector_; 1822 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1823 size_t bin_size = object_addr - context->prev_; 1824 // Add the bin consisting of the end of the previous object to the start of the current object. 1825 collector->AddBin(bin_size, context->prev_); 1826 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1827 } 1828 1829 void AddBin(size_t size, uintptr_t position) { 1830 if (size != 0) { 1831 bins_.insert(std::make_pair(size, position)); 1832 } 1833 } 1834 1835 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1836 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1837 // allocator. 1838 UNUSED(space); 1839 return false; 1840 } 1841 1842 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1843 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1844 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1845 mirror::Object* forward_address; 1846 // Find the smallest bin which we can move obj in. 1847 auto it = bins_.lower_bound(object_size); 1848 if (it == bins_.end()) { 1849 // No available space in the bins, place it in the target space instead (grows the zygote 1850 // space). 1851 size_t bytes_allocated; 1852 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1853 if (to_space_live_bitmap_ != nullptr) { 1854 to_space_live_bitmap_->Set(forward_address); 1855 } else { 1856 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1857 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1858 } 1859 } else { 1860 size_t size = it->first; 1861 uintptr_t pos = it->second; 1862 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1863 forward_address = reinterpret_cast<mirror::Object*>(pos); 1864 // Set the live and mark bits so that sweeping system weaks works properly. 1865 bin_live_bitmap_->Set(forward_address); 1866 bin_mark_bitmap_->Set(forward_address); 1867 DCHECK_GE(size, object_size); 1868 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1869 } 1870 // Copy the object over to its new location. 1871 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1872 if (kUseBakerOrBrooksReadBarrier) { 1873 obj->AssertReadBarrierPointer(); 1874 if (kUseBrooksReadBarrier) { 1875 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1876 forward_address->SetReadBarrierPointer(forward_address); 1877 } 1878 forward_address->AssertReadBarrierPointer(); 1879 } 1880 return forward_address; 1881 } 1882}; 1883 1884void Heap::UnBindBitmaps() { 1885 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1886 for (const auto& space : GetContinuousSpaces()) { 1887 if (space->IsContinuousMemMapAllocSpace()) { 1888 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1889 if (alloc_space->HasBoundBitmaps()) { 1890 alloc_space->UnBindBitmaps(); 1891 } 1892 } 1893 } 1894} 1895 1896void Heap::PreZygoteFork() { 1897 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1898 Thread* self = Thread::Current(); 1899 MutexLock mu(self, zygote_creation_lock_); 1900 // Try to see if we have any Zygote spaces. 1901 if (HasZygoteSpace()) { 1902 LOG(WARNING) << __FUNCTION__ << " called when we already have a zygote space."; 1903 return; 1904 } 1905 Runtime::Current()->GetInternTable()->SwapPostZygoteWithPreZygote(); 1906 Runtime::Current()->GetClassLinker()->MoveClassTableToPreZygote(); 1907 VLOG(heap) << "Starting PreZygoteFork"; 1908 // Trim the pages at the end of the non moving space. 1909 non_moving_space_->Trim(); 1910 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1911 // there. 1912 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1913 const bool same_space = non_moving_space_ == main_space_; 1914 if (kCompactZygote) { 1915 // Can't compact if the non moving space is the same as the main space. 1916 DCHECK(semi_space_collector_ != nullptr); 1917 // Temporarily disable rosalloc verification because the zygote 1918 // compaction will mess up the rosalloc internal metadata. 1919 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1920 ZygoteCompactingCollector zygote_collector(this); 1921 zygote_collector.BuildBins(non_moving_space_); 1922 // Create a new bump pointer space which we will compact into. 1923 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1924 non_moving_space_->Limit()); 1925 // Compact the bump pointer space to a new zygote bump pointer space. 1926 bool reset_main_space = false; 1927 if (IsMovingGc(collector_type_)) { 1928 zygote_collector.SetFromSpace(bump_pointer_space_); 1929 } else { 1930 CHECK(main_space_ != nullptr); 1931 // Copy from the main space. 1932 zygote_collector.SetFromSpace(main_space_); 1933 reset_main_space = true; 1934 } 1935 zygote_collector.SetToSpace(&target_space); 1936 zygote_collector.SetSwapSemiSpaces(false); 1937 zygote_collector.Run(kGcCauseCollectorTransition, false); 1938 if (reset_main_space) { 1939 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1940 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1941 MemMap* mem_map = main_space_->ReleaseMemMap(); 1942 RemoveSpace(main_space_); 1943 space::Space* old_main_space = main_space_; 1944 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1945 delete old_main_space; 1946 AddSpace(main_space_); 1947 } else { 1948 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1949 } 1950 if (temp_space_ != nullptr) { 1951 CHECK(temp_space_->IsEmpty()); 1952 } 1953 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1954 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1955 // Update the end and write out image. 1956 non_moving_space_->SetEnd(target_space.End()); 1957 non_moving_space_->SetLimit(target_space.Limit()); 1958 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1959 } 1960 // Change the collector to the post zygote one. 1961 ChangeCollector(foreground_collector_type_); 1962 // Save the old space so that we can remove it after we complete creating the zygote space. 1963 space::MallocSpace* old_alloc_space = non_moving_space_; 1964 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1965 // the remaining available space. 1966 // Remove the old space before creating the zygote space since creating the zygote space sets 1967 // the old alloc space's bitmaps to nullptr. 1968 RemoveSpace(old_alloc_space); 1969 if (collector::SemiSpace::kUseRememberedSet) { 1970 // Sanity bound check. 1971 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1972 // Remove the remembered set for the now zygote space (the old 1973 // non-moving space). Note now that we have compacted objects into 1974 // the zygote space, the data in the remembered set is no longer 1975 // needed. The zygote space will instead have a mod-union table 1976 // from this point on. 1977 RemoveRememberedSet(old_alloc_space); 1978 } 1979 zygote_space_ = old_alloc_space->CreateZygoteSpace("alloc space", low_memory_mode_, 1980 &non_moving_space_); 1981 CHECK(!non_moving_space_->CanMoveObjects()); 1982 if (same_space) { 1983 main_space_ = non_moving_space_; 1984 SetSpaceAsDefault(main_space_); 1985 } 1986 delete old_alloc_space; 1987 CHECK(HasZygoteSpace()) << "Failed creating zygote space"; 1988 AddSpace(zygote_space_); 1989 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1990 AddSpace(non_moving_space_); 1991 // Create the zygote space mod union table. 1992 accounting::ModUnionTable* mod_union_table = 1993 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, 1994 zygote_space_); 1995 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1996 // Set all the cards in the mod-union table since we don't know which objects contain references 1997 // to large objects. 1998 mod_union_table->SetCards(); 1999 AddModUnionTable(mod_union_table); 2000 if (collector::SemiSpace::kUseRememberedSet) { 2001 // Add a new remembered set for the post-zygote non-moving space. 2002 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 2003 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 2004 non_moving_space_); 2005 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 2006 << "Failed to create post-zygote non-moving space remembered set"; 2007 AddRememberedSet(post_zygote_non_moving_space_rem_set); 2008 } 2009} 2010 2011void Heap::FlushAllocStack() { 2012 MarkAllocStackAsLive(allocation_stack_.get()); 2013 allocation_stack_->Reset(); 2014} 2015 2016void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2017 accounting::ContinuousSpaceBitmap* bitmap2, 2018 accounting::LargeObjectBitmap* large_objects, 2019 accounting::ObjectStack* stack) { 2020 DCHECK(bitmap1 != nullptr); 2021 DCHECK(bitmap2 != nullptr); 2022 mirror::Object** limit = stack->End(); 2023 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2024 const mirror::Object* obj = *it; 2025 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2026 if (bitmap1->HasAddress(obj)) { 2027 bitmap1->Set(obj); 2028 } else if (bitmap2->HasAddress(obj)) { 2029 bitmap2->Set(obj); 2030 } else { 2031 DCHECK(large_objects != nullptr); 2032 large_objects->Set(obj); 2033 } 2034 } 2035 } 2036} 2037 2038void Heap::SwapSemiSpaces() { 2039 CHECK(bump_pointer_space_ != nullptr); 2040 CHECK(temp_space_ != nullptr); 2041 std::swap(bump_pointer_space_, temp_space_); 2042} 2043 2044void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2045 space::ContinuousMemMapAllocSpace* source_space, 2046 GcCause gc_cause) { 2047 CHECK(kMovingCollector); 2048 if (target_space != source_space) { 2049 // Don't swap spaces since this isn't a typical semi space collection. 2050 semi_space_collector_->SetSwapSemiSpaces(false); 2051 semi_space_collector_->SetFromSpace(source_space); 2052 semi_space_collector_->SetToSpace(target_space); 2053 semi_space_collector_->Run(gc_cause, false); 2054 } else { 2055 CHECK(target_space->IsBumpPointerSpace()) 2056 << "In-place compaction is only supported for bump pointer spaces"; 2057 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2058 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2059 } 2060} 2061 2062collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2063 bool clear_soft_references) { 2064 Thread* self = Thread::Current(); 2065 Runtime* runtime = Runtime::Current(); 2066 // If the heap can't run the GC, silently fail and return that no GC was run. 2067 switch (gc_type) { 2068 case collector::kGcTypePartial: { 2069 if (!HasZygoteSpace()) { 2070 return collector::kGcTypeNone; 2071 } 2072 break; 2073 } 2074 default: { 2075 // Other GC types don't have any special cases which makes them not runnable. The main case 2076 // here is full GC. 2077 } 2078 } 2079 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2080 Locks::mutator_lock_->AssertNotHeld(self); 2081 if (self->IsHandlingStackOverflow()) { 2082 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2083 } 2084 bool compacting_gc; 2085 { 2086 gc_complete_lock_->AssertNotHeld(self); 2087 ScopedThreadStateChange tsc2(self, kWaitingForGcToComplete); 2088 MutexLock mu(self, *gc_complete_lock_); 2089 // Ensure there is only one GC at a time. 2090 WaitForGcToCompleteLocked(gc_cause, self); 2091 compacting_gc = IsMovingGc(collector_type_); 2092 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2093 if (compacting_gc && disable_moving_gc_count_ != 0) { 2094 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2095 return collector::kGcTypeNone; 2096 } 2097 collector_type_running_ = collector_type_; 2098 } 2099 2100 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2101 ++runtime->GetStats()->gc_for_alloc_count; 2102 ++self->GetStats()->gc_for_alloc_count; 2103 } 2104 uint64_t gc_start_time_ns = NanoTime(); 2105 uint64_t gc_start_size = GetBytesAllocated(); 2106 // Approximate allocation rate in bytes / second. 2107 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2108 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2109 if (LIKELY(ms_delta != 0)) { 2110 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2111 ATRACE_INT("Allocation rate KB/s", allocation_rate_ / KB); 2112 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2113 } 2114 2115 DCHECK_LT(gc_type, collector::kGcTypeMax); 2116 DCHECK_NE(gc_type, collector::kGcTypeNone); 2117 2118 collector::GarbageCollector* collector = nullptr; 2119 // TODO: Clean this up. 2120 if (compacting_gc) { 2121 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2122 current_allocator_ == kAllocatorTypeTLAB); 2123 switch (collector_type_) { 2124 case kCollectorTypeSS: 2125 // Fall-through. 2126 case kCollectorTypeGSS: 2127 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2128 semi_space_collector_->SetToSpace(temp_space_); 2129 semi_space_collector_->SetSwapSemiSpaces(true); 2130 collector = semi_space_collector_; 2131 break; 2132 case kCollectorTypeCC: 2133 collector = concurrent_copying_collector_; 2134 break; 2135 case kCollectorTypeMC: 2136 mark_compact_collector_->SetSpace(bump_pointer_space_); 2137 collector = mark_compact_collector_; 2138 break; 2139 default: 2140 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2141 } 2142 if (collector != mark_compact_collector_) { 2143 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2144 CHECK(temp_space_->IsEmpty()); 2145 } 2146 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2147 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2148 current_allocator_ == kAllocatorTypeDlMalloc) { 2149 collector = FindCollectorByGcType(gc_type); 2150 } else { 2151 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2152 } 2153 if (IsGcConcurrent()) { 2154 // Disable concurrent GC check so that we don't have spammy JNI requests. 2155 // This gets recalculated in GrowForUtilization. It is important that it is disabled / 2156 // calculated in the same thread so that there aren't any races that can cause it to become 2157 // permanantly disabled. b/17942071 2158 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2159 } 2160 CHECK(collector != nullptr) 2161 << "Could not find garbage collector with collector_type=" 2162 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2163 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2164 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2165 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2166 RequestHeapTrim(); 2167 // Enqueue cleared references. 2168 reference_processor_.EnqueueClearedReferences(self); 2169 // Grow the heap so that we know when to perform the next GC. 2170 GrowForUtilization(collector); 2171 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2172 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2173 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2174 // (mutator time blocked >= long_pause_log_threshold_). 2175 bool log_gc = gc_cause == kGcCauseExplicit; 2176 if (!log_gc && CareAboutPauseTimes()) { 2177 // GC for alloc pauses the allocating thread, so consider it as a pause. 2178 log_gc = duration > long_gc_log_threshold_ || 2179 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2180 for (uint64_t pause : pause_times) { 2181 log_gc = log_gc || pause >= long_pause_log_threshold_; 2182 } 2183 } 2184 if (log_gc) { 2185 const size_t percent_free = GetPercentFree(); 2186 const size_t current_heap_size = GetBytesAllocated(); 2187 const size_t total_memory = GetTotalMemory(); 2188 std::ostringstream pause_string; 2189 for (size_t i = 0; i < pause_times.size(); ++i) { 2190 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2191 << ((i != pause_times.size() - 1) ? "," : ""); 2192 } 2193 LOG(INFO) << gc_cause << " " << collector->GetName() 2194 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2195 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2196 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2197 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2198 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2199 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2200 << " total " << PrettyDuration((duration / 1000) * 1000); 2201 VLOG(heap) << Dumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2202 } 2203 FinishGC(self, gc_type); 2204 // Inform DDMS that a GC completed. 2205 Dbg::GcDidFinish(); 2206 return gc_type; 2207} 2208 2209void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2210 MutexLock mu(self, *gc_complete_lock_); 2211 collector_type_running_ = kCollectorTypeNone; 2212 if (gc_type != collector::kGcTypeNone) { 2213 last_gc_type_ = gc_type; 2214 } 2215 // Wake anyone who may have been waiting for the GC to complete. 2216 gc_complete_cond_->Broadcast(self); 2217} 2218 2219static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2220 RootType /*root_type*/) { 2221 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2222 if (*root == obj) { 2223 LOG(INFO) << "Object " << obj << " is a root"; 2224 } 2225} 2226 2227class ScanVisitor { 2228 public: 2229 void operator()(const mirror::Object* obj) const { 2230 LOG(ERROR) << "Would have rescanned object " << obj; 2231 } 2232}; 2233 2234// Verify a reference from an object. 2235class VerifyReferenceVisitor { 2236 public: 2237 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2238 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2239 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2240 2241 size_t GetFailureCount() const { 2242 return fail_count_->LoadSequentiallyConsistent(); 2243 } 2244 2245 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2246 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2247 UNUSED(klass); 2248 if (verify_referent_) { 2249 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2250 } 2251 } 2252 2253 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2254 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2255 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2256 } 2257 2258 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2259 return heap_->IsLiveObjectLocked(obj, true, false, true); 2260 } 2261 2262 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2263 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2264 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2265 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2266 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2267 << " thread_id= " << thread_id << " root_type= " << root_type; 2268 } 2269 } 2270 2271 private: 2272 // TODO: Fix the no thread safety analysis. 2273 // Returns false on failure. 2274 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2275 NO_THREAD_SAFETY_ANALYSIS { 2276 if (ref == nullptr || IsLive(ref)) { 2277 // Verify that the reference is live. 2278 return true; 2279 } 2280 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2281 // Print message on only on first failure to prevent spam. 2282 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2283 } 2284 if (obj != nullptr) { 2285 // Only do this part for non roots. 2286 accounting::CardTable* card_table = heap_->GetCardTable(); 2287 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2288 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2289 uint8_t* card_addr = card_table->CardFromAddr(obj); 2290 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2291 << offset << "\n card value = " << static_cast<int>(*card_addr); 2292 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2293 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2294 } else { 2295 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2296 } 2297 2298 // Attempt to find the class inside of the recently freed objects. 2299 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2300 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2301 space::MallocSpace* space = ref_space->AsMallocSpace(); 2302 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2303 if (ref_class != nullptr) { 2304 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2305 << PrettyClass(ref_class); 2306 } else { 2307 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2308 } 2309 } 2310 2311 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2312 ref->GetClass()->IsClass()) { 2313 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2314 } else { 2315 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2316 << ") is not a valid heap address"; 2317 } 2318 2319 card_table->CheckAddrIsInCardTable(reinterpret_cast<const uint8_t*>(obj)); 2320 void* cover_begin = card_table->AddrFromCard(card_addr); 2321 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2322 accounting::CardTable::kCardSize); 2323 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2324 << "-" << cover_end; 2325 accounting::ContinuousSpaceBitmap* bitmap = 2326 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2327 2328 if (bitmap == nullptr) { 2329 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2330 if (!VerifyClassClass(obj->GetClass())) { 2331 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2332 } 2333 } else { 2334 // Print out how the object is live. 2335 if (bitmap->Test(obj)) { 2336 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2337 } 2338 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2339 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2340 } 2341 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2342 LOG(ERROR) << "Object " << obj << " found in live stack"; 2343 } 2344 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2345 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2346 } 2347 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2348 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2349 } 2350 // Attempt to see if the card table missed the reference. 2351 ScanVisitor scan_visitor; 2352 uint8_t* byte_cover_begin = reinterpret_cast<uint8_t*>(card_table->AddrFromCard(card_addr)); 2353 card_table->Scan(bitmap, byte_cover_begin, 2354 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2355 } 2356 2357 // Search to see if any of the roots reference our object. 2358 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2359 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2360 2361 // Search to see if any of the roots reference our reference. 2362 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2363 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2364 } 2365 return false; 2366 } 2367 2368 Heap* const heap_; 2369 Atomic<size_t>* const fail_count_; 2370 const bool verify_referent_; 2371}; 2372 2373// Verify all references within an object, for use with HeapBitmap::Visit. 2374class VerifyObjectVisitor { 2375 public: 2376 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2377 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2378 } 2379 2380 void operator()(mirror::Object* obj) const 2381 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2382 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2383 // be live or else how did we find it in the live bitmap? 2384 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2385 // The class doesn't count as a reference but we should verify it anyways. 2386 obj->VisitReferences<true>(visitor, visitor); 2387 } 2388 2389 static void VisitCallback(mirror::Object* obj, void* arg) 2390 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2391 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2392 visitor->operator()(obj); 2393 } 2394 2395 size_t GetFailureCount() const { 2396 return fail_count_->LoadSequentiallyConsistent(); 2397 } 2398 2399 private: 2400 Heap* const heap_; 2401 Atomic<size_t>* const fail_count_; 2402 const bool verify_referent_; 2403}; 2404 2405void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2406 // Slow path, the allocation stack push back must have already failed. 2407 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2408 do { 2409 // TODO: Add handle VerifyObject. 2410 StackHandleScope<1> hs(self); 2411 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2412 // Push our object into the reserve region of the allocaiton stack. This is only required due 2413 // to heap verification requiring that roots are live (either in the live bitmap or in the 2414 // allocation stack). 2415 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2416 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2417 } while (!allocation_stack_->AtomicPushBack(*obj)); 2418} 2419 2420void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2421 // Slow path, the allocation stack push back must have already failed. 2422 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2423 mirror::Object** start_address; 2424 mirror::Object** end_address; 2425 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2426 &end_address)) { 2427 // TODO: Add handle VerifyObject. 2428 StackHandleScope<1> hs(self); 2429 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2430 // Push our object into the reserve region of the allocaiton stack. This is only required due 2431 // to heap verification requiring that roots are live (either in the live bitmap or in the 2432 // allocation stack). 2433 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2434 // Push into the reserve allocation stack. 2435 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2436 } 2437 self->SetThreadLocalAllocationStack(start_address, end_address); 2438 // Retry on the new thread-local allocation stack. 2439 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2440} 2441 2442// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2443size_t Heap::VerifyHeapReferences(bool verify_referents) { 2444 Thread* self = Thread::Current(); 2445 Locks::mutator_lock_->AssertExclusiveHeld(self); 2446 // Lets sort our allocation stacks so that we can efficiently binary search them. 2447 allocation_stack_->Sort(); 2448 live_stack_->Sort(); 2449 // Since we sorted the allocation stack content, need to revoke all 2450 // thread-local allocation stacks. 2451 RevokeAllThreadLocalAllocationStacks(self); 2452 Atomic<size_t> fail_count_(0); 2453 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2454 // Verify objects in the allocation stack since these will be objects which were: 2455 // 1. Allocated prior to the GC (pre GC verification). 2456 // 2. Allocated during the GC (pre sweep GC verification). 2457 // We don't want to verify the objects in the live stack since they themselves may be 2458 // pointing to dead objects if they are not reachable. 2459 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2460 // Verify the roots: 2461 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2462 if (visitor.GetFailureCount() > 0) { 2463 // Dump mod-union tables. 2464 for (const auto& table_pair : mod_union_tables_) { 2465 accounting::ModUnionTable* mod_union_table = table_pair.second; 2466 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2467 } 2468 // Dump remembered sets. 2469 for (const auto& table_pair : remembered_sets_) { 2470 accounting::RememberedSet* remembered_set = table_pair.second; 2471 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2472 } 2473 DumpSpaces(LOG(ERROR)); 2474 } 2475 return visitor.GetFailureCount(); 2476} 2477 2478class VerifyReferenceCardVisitor { 2479 public: 2480 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2481 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2482 Locks::heap_bitmap_lock_) 2483 : heap_(heap), failed_(failed) { 2484 } 2485 2486 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2487 // annotalysis on visitors. 2488 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2489 NO_THREAD_SAFETY_ANALYSIS { 2490 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2491 // Filter out class references since changing an object's class does not mark the card as dirty. 2492 // Also handles large objects, since the only reference they hold is a class reference. 2493 if (ref != nullptr && !ref->IsClass()) { 2494 accounting::CardTable* card_table = heap_->GetCardTable(); 2495 // If the object is not dirty and it is referencing something in the live stack other than 2496 // class, then it must be on a dirty card. 2497 if (!card_table->AddrIsInCardTable(obj)) { 2498 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2499 *failed_ = true; 2500 } else if (!card_table->IsDirty(obj)) { 2501 // TODO: Check mod-union tables. 2502 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2503 // kCardDirty - 1 if it didnt get touched since we aged it. 2504 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2505 if (live_stack->ContainsSorted(ref)) { 2506 if (live_stack->ContainsSorted(obj)) { 2507 LOG(ERROR) << "Object " << obj << " found in live stack"; 2508 } 2509 if (heap_->GetLiveBitmap()->Test(obj)) { 2510 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2511 } 2512 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2513 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2514 2515 // Print which field of the object is dead. 2516 if (!obj->IsObjectArray()) { 2517 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2518 CHECK(klass != NULL); 2519 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2520 : klass->GetIFields(); 2521 CHECK(fields != NULL); 2522 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2523 mirror::ArtField* cur = fields->Get(i); 2524 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2525 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2526 << PrettyField(cur); 2527 break; 2528 } 2529 } 2530 } else { 2531 mirror::ObjectArray<mirror::Object>* object_array = 2532 obj->AsObjectArray<mirror::Object>(); 2533 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2534 if (object_array->Get(i) == ref) { 2535 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2536 } 2537 } 2538 } 2539 2540 *failed_ = true; 2541 } 2542 } 2543 } 2544 } 2545 2546 private: 2547 Heap* const heap_; 2548 bool* const failed_; 2549}; 2550 2551class VerifyLiveStackReferences { 2552 public: 2553 explicit VerifyLiveStackReferences(Heap* heap) 2554 : heap_(heap), 2555 failed_(false) {} 2556 2557 void operator()(mirror::Object* obj) const 2558 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2559 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2560 obj->VisitReferences<true>(visitor, VoidFunctor()); 2561 } 2562 2563 bool Failed() const { 2564 return failed_; 2565 } 2566 2567 private: 2568 Heap* const heap_; 2569 bool failed_; 2570}; 2571 2572bool Heap::VerifyMissingCardMarks() { 2573 Thread* self = Thread::Current(); 2574 Locks::mutator_lock_->AssertExclusiveHeld(self); 2575 // We need to sort the live stack since we binary search it. 2576 live_stack_->Sort(); 2577 // Since we sorted the allocation stack content, need to revoke all 2578 // thread-local allocation stacks. 2579 RevokeAllThreadLocalAllocationStacks(self); 2580 VerifyLiveStackReferences visitor(this); 2581 GetLiveBitmap()->Visit(visitor); 2582 // We can verify objects in the live stack since none of these should reference dead objects. 2583 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2584 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2585 visitor(*it); 2586 } 2587 } 2588 return !visitor.Failed(); 2589} 2590 2591void Heap::SwapStacks(Thread* self) { 2592 UNUSED(self); 2593 if (kUseThreadLocalAllocationStack) { 2594 live_stack_->AssertAllZero(); 2595 } 2596 allocation_stack_.swap(live_stack_); 2597} 2598 2599void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2600 // This must be called only during the pause. 2601 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2602 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2603 MutexLock mu2(self, *Locks::thread_list_lock_); 2604 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2605 for (Thread* t : thread_list) { 2606 t->RevokeThreadLocalAllocationStack(); 2607 } 2608} 2609 2610void Heap::AssertThreadLocalBuffersAreRevoked(Thread* thread) { 2611 if (kIsDebugBuild) { 2612 if (rosalloc_space_ != nullptr) { 2613 rosalloc_space_->AssertThreadLocalBuffersAreRevoked(thread); 2614 } 2615 if (bump_pointer_space_ != nullptr) { 2616 bump_pointer_space_->AssertThreadLocalBuffersAreRevoked(thread); 2617 } 2618 } 2619} 2620 2621void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2622 if (kIsDebugBuild) { 2623 if (bump_pointer_space_ != nullptr) { 2624 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2625 } 2626 } 2627} 2628 2629accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2630 auto it = mod_union_tables_.find(space); 2631 if (it == mod_union_tables_.end()) { 2632 return nullptr; 2633 } 2634 return it->second; 2635} 2636 2637accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2638 auto it = remembered_sets_.find(space); 2639 if (it == remembered_sets_.end()) { 2640 return nullptr; 2641 } 2642 return it->second; 2643} 2644 2645void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2646 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2647 // Clear cards and keep track of cards cleared in the mod-union table. 2648 for (const auto& space : continuous_spaces_) { 2649 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2650 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2651 if (table != nullptr) { 2652 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2653 "ImageModUnionClearCards"; 2654 TimingLogger::ScopedTiming t2(name, timings); 2655 table->ClearCards(); 2656 } else if (use_rem_sets && rem_set != nullptr) { 2657 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2658 << static_cast<int>(collector_type_); 2659 TimingLogger::ScopedTiming t2("AllocSpaceRemSetClearCards", timings); 2660 rem_set->ClearCards(); 2661 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2662 TimingLogger::ScopedTiming t2("AllocSpaceClearCards", timings); 2663 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2664 // were dirty before the GC started. 2665 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2666 // -> clean(cleaning thread). 2667 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2668 // roots and then we scan / update mod union tables after. We will always scan either card. 2669 // If we end up with the non aged card, we scan it it in the pause. 2670 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2671 VoidFunctor()); 2672 } 2673 } 2674} 2675 2676static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2677} 2678 2679void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2680 Thread* const self = Thread::Current(); 2681 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2682 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2683 if (verify_pre_gc_heap_) { 2684 TimingLogger::ScopedTiming t2("(Paused)PreGcVerifyHeapReferences", timings); 2685 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2686 size_t failures = VerifyHeapReferences(); 2687 if (failures > 0) { 2688 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2689 << " failures"; 2690 } 2691 } 2692 // Check that all objects which reference things in the live stack are on dirty cards. 2693 if (verify_missing_card_marks_) { 2694 TimingLogger::ScopedTiming t2("(Paused)PreGcVerifyMissingCardMarks", timings); 2695 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2696 SwapStacks(self); 2697 // Sort the live stack so that we can quickly binary search it later. 2698 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2699 << " missing card mark verification failed\n" << DumpSpaces(); 2700 SwapStacks(self); 2701 } 2702 if (verify_mod_union_table_) { 2703 TimingLogger::ScopedTiming t2("(Paused)PreGcVerifyModUnionTables", timings); 2704 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2705 for (const auto& table_pair : mod_union_tables_) { 2706 accounting::ModUnionTable* mod_union_table = table_pair.second; 2707 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2708 mod_union_table->Verify(); 2709 } 2710 } 2711} 2712 2713void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2714 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2715 collector::GarbageCollector::ScopedPause pause(gc); 2716 PreGcVerificationPaused(gc); 2717 } 2718} 2719 2720void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2721 UNUSED(gc); 2722 // TODO: Add a new runtime option for this? 2723 if (verify_pre_gc_rosalloc_) { 2724 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2725 } 2726} 2727 2728void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2729 Thread* const self = Thread::Current(); 2730 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2731 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2732 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2733 // reachable objects. 2734 if (verify_pre_sweeping_heap_) { 2735 TimingLogger::ScopedTiming t2("(Paused)PostSweepingVerifyHeapReferences", timings); 2736 CHECK_NE(self->GetState(), kRunnable); 2737 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2738 // Swapping bound bitmaps does nothing. 2739 gc->SwapBitmaps(); 2740 // Pass in false since concurrent reference processing can mean that the reference referents 2741 // may point to dead objects at the point which PreSweepingGcVerification is called. 2742 size_t failures = VerifyHeapReferences(false); 2743 if (failures > 0) { 2744 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2745 << " failures"; 2746 } 2747 gc->SwapBitmaps(); 2748 } 2749 if (verify_pre_sweeping_rosalloc_) { 2750 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2751 } 2752} 2753 2754void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2755 // Only pause if we have to do some verification. 2756 Thread* const self = Thread::Current(); 2757 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2758 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2759 if (verify_system_weaks_) { 2760 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2761 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2762 mark_sweep->VerifySystemWeaks(); 2763 } 2764 if (verify_post_gc_rosalloc_) { 2765 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2766 } 2767 if (verify_post_gc_heap_) { 2768 TimingLogger::ScopedTiming t2("(Paused)PostGcVerifyHeapReferences", timings); 2769 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2770 size_t failures = VerifyHeapReferences(); 2771 if (failures > 0) { 2772 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2773 << " failures"; 2774 } 2775 } 2776} 2777 2778void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2779 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2780 collector::GarbageCollector::ScopedPause pause(gc); 2781 PostGcVerificationPaused(gc); 2782 } 2783} 2784 2785void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2786 TimingLogger::ScopedTiming t(name, timings); 2787 for (const auto& space : continuous_spaces_) { 2788 if (space->IsRosAllocSpace()) { 2789 VLOG(heap) << name << " : " << space->GetName(); 2790 space->AsRosAllocSpace()->Verify(); 2791 } 2792 } 2793} 2794 2795collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2796 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2797 MutexLock mu(self, *gc_complete_lock_); 2798 return WaitForGcToCompleteLocked(cause, self); 2799} 2800 2801collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2802 collector::GcType last_gc_type = collector::kGcTypeNone; 2803 uint64_t wait_start = NanoTime(); 2804 while (collector_type_running_ != kCollectorTypeNone) { 2805 ATRACE_BEGIN("GC: Wait For Completion"); 2806 // We must wait, change thread state then sleep on gc_complete_cond_; 2807 gc_complete_cond_->Wait(self); 2808 last_gc_type = last_gc_type_; 2809 ATRACE_END(); 2810 } 2811 uint64_t wait_time = NanoTime() - wait_start; 2812 total_wait_time_ += wait_time; 2813 if (wait_time > long_pause_log_threshold_) { 2814 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2815 << " for cause " << cause; 2816 } 2817 return last_gc_type; 2818} 2819 2820void Heap::DumpForSigQuit(std::ostream& os) { 2821 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2822 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2823 DumpGcPerformanceInfo(os); 2824} 2825 2826size_t Heap::GetPercentFree() { 2827 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2828} 2829 2830void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2831 if (max_allowed_footprint > GetMaxMemory()) { 2832 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2833 << PrettySize(GetMaxMemory()); 2834 max_allowed_footprint = GetMaxMemory(); 2835 } 2836 max_allowed_footprint_ = max_allowed_footprint; 2837} 2838 2839bool Heap::IsMovableObject(const mirror::Object* obj) const { 2840 if (kMovingCollector) { 2841 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2842 if (space != nullptr) { 2843 // TODO: Check large object? 2844 return space->CanMoveObjects(); 2845 } 2846 } 2847 return false; 2848} 2849 2850void Heap::UpdateMaxNativeFootprint() { 2851 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2852 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2853 size_t target_size = native_size / GetTargetHeapUtilization(); 2854 if (target_size > native_size + max_free_) { 2855 target_size = native_size + max_free_; 2856 } else if (target_size < native_size + min_free_) { 2857 target_size = native_size + min_free_; 2858 } 2859 native_footprint_gc_watermark_ = std::min(growth_limit_, target_size); 2860} 2861 2862collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2863 for (const auto& collector : garbage_collectors_) { 2864 if (collector->GetCollectorType() == collector_type_ && 2865 collector->GetGcType() == gc_type) { 2866 return collector; 2867 } 2868 } 2869 return nullptr; 2870} 2871 2872double Heap::HeapGrowthMultiplier() const { 2873 // If we don't care about pause times we are background, so return 1.0. 2874 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2875 return 1.0; 2876 } 2877 return foreground_heap_growth_multiplier_; 2878} 2879 2880void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2881 // We know what our utilization is at this moment. 2882 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2883 const uint64_t bytes_allocated = GetBytesAllocated(); 2884 last_gc_size_ = bytes_allocated; 2885 last_gc_time_ns_ = NanoTime(); 2886 uint64_t target_size; 2887 collector::GcType gc_type = collector_ran->GetGcType(); 2888 if (gc_type != collector::kGcTypeSticky) { 2889 // Grow the heap for non sticky GC. 2890 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2891 // foreground. 2892 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2893 CHECK_GE(delta, 0); 2894 target_size = bytes_allocated + delta * multiplier; 2895 target_size = std::min(target_size, 2896 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2897 target_size = std::max(target_size, 2898 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2899 native_need_to_run_finalization_ = true; 2900 next_gc_type_ = collector::kGcTypeSticky; 2901 } else { 2902 collector::GcType non_sticky_gc_type = 2903 HasZygoteSpace() ? collector::kGcTypePartial : collector::kGcTypeFull; 2904 // Find what the next non sticky collector will be. 2905 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2906 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2907 // do another sticky collection next. 2908 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2909 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2910 // if the sticky GC throughput always remained >= the full/partial throughput. 2911 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2912 non_sticky_collector->GetEstimatedMeanThroughput() && 2913 non_sticky_collector->NumberOfIterations() > 0 && 2914 bytes_allocated <= max_allowed_footprint_) { 2915 next_gc_type_ = collector::kGcTypeSticky; 2916 } else { 2917 next_gc_type_ = non_sticky_gc_type; 2918 } 2919 // If we have freed enough memory, shrink the heap back down. 2920 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2921 target_size = bytes_allocated + max_free_; 2922 } else { 2923 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2924 } 2925 } 2926 if (!ignore_max_footprint_) { 2927 SetIdealFootprint(target_size); 2928 if (IsGcConcurrent()) { 2929 // Calculate when to perform the next ConcurrentGC. 2930 // Calculate the estimated GC duration. 2931 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2932 // Estimate how many remaining bytes we will have when we need to start the next GC. 2933 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2934 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2935 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2936 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2937 // A never going to happen situation that from the estimated allocation rate we will exceed 2938 // the applications entire footprint with the given estimated allocation rate. Schedule 2939 // another GC nearly straight away. 2940 remaining_bytes = kMinConcurrentRemainingBytes; 2941 } 2942 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2943 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2944 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2945 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2946 // right away. 2947 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2948 static_cast<size_t>(bytes_allocated)); 2949 } 2950 } 2951} 2952 2953void Heap::ClearGrowthLimit() { 2954 growth_limit_ = capacity_; 2955 non_moving_space_->ClearGrowthLimit(); 2956} 2957 2958void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2959 ScopedObjectAccess soa(self); 2960 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2961 jvalue args[1]; 2962 args[0].l = arg.get(); 2963 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2964 // Restore object in case it gets moved. 2965 *object = soa.Decode<mirror::Object*>(arg.get()); 2966} 2967 2968void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2969 StackHandleScope<1> hs(self); 2970 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2971 RequestConcurrentGC(self); 2972} 2973 2974void Heap::RequestConcurrentGC(Thread* self) { 2975 // Make sure that we can do a concurrent GC. 2976 Runtime* runtime = Runtime::Current(); 2977 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2978 self->IsHandlingStackOverflow()) { 2979 return; 2980 } 2981 JNIEnv* env = self->GetJniEnv(); 2982 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2983 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2984 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2985 WellKnownClasses::java_lang_Daemons_requestGC); 2986 CHECK(!env->ExceptionCheck()); 2987} 2988 2989void Heap::ConcurrentGC(Thread* self) { 2990 if (Runtime::Current()->IsShuttingDown(self)) { 2991 return; 2992 } 2993 // Wait for any GCs currently running to finish. 2994 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2995 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2996 // instead. E.g. can't do partial, so do full instead. 2997 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2998 collector::kGcTypeNone) { 2999 for (collector::GcType gc_type : gc_plan_) { 3000 // Attempt to run the collector, if we succeed, we are done. 3001 if (gc_type > next_gc_type_ && 3002 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 3003 break; 3004 } 3005 } 3006 } 3007 } 3008} 3009 3010void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 3011 Thread* self = Thread::Current(); 3012 { 3013 MutexLock mu(self, *heap_trim_request_lock_); 3014 if (desired_collector_type_ == desired_collector_type) { 3015 return; 3016 } 3017 heap_transition_or_trim_target_time_ = 3018 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 3019 desired_collector_type_ = desired_collector_type; 3020 } 3021 SignalHeapTrimDaemon(self); 3022} 3023 3024void Heap::RequestHeapTrim() { 3025 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 3026 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 3027 // a space it will hold its lock and can become a cause of jank. 3028 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 3029 // forking. 3030 3031 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 3032 // because that only marks object heads, so a large array looks like lots of empty space. We 3033 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 3034 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3035 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3036 // not how much use we're making of those pages. 3037 3038 Thread* self = Thread::Current(); 3039 Runtime* runtime = Runtime::Current(); 3040 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 3041 runtime->IsZygote()) { 3042 // Ignore the request if we are the zygote to prevent app launching lag due to sleep in heap 3043 // trimmer daemon. b/17310019 3044 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3045 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3046 // as we don't hold the lock while requesting the trim). 3047 return; 3048 } 3049 { 3050 MutexLock mu(self, *heap_trim_request_lock_); 3051 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3052 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3053 // just yet. 3054 return; 3055 } 3056 heap_trim_request_pending_ = true; 3057 uint64_t current_time = NanoTime(); 3058 if (heap_transition_or_trim_target_time_ < current_time) { 3059 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 3060 } 3061 } 3062 // Notify the daemon thread which will actually do the heap trim. 3063 SignalHeapTrimDaemon(self); 3064} 3065 3066void Heap::SignalHeapTrimDaemon(Thread* self) { 3067 JNIEnv* env = self->GetJniEnv(); 3068 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3069 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3070 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3071 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3072 CHECK(!env->ExceptionCheck()); 3073} 3074 3075void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3076 if (rosalloc_space_ != nullptr) { 3077 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3078 } 3079 if (bump_pointer_space_ != nullptr) { 3080 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3081 } 3082} 3083 3084void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3085 if (rosalloc_space_ != nullptr) { 3086 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3087 } 3088} 3089 3090void Heap::RevokeAllThreadLocalBuffers() { 3091 if (rosalloc_space_ != nullptr) { 3092 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3093 } 3094 if (bump_pointer_space_ != nullptr) { 3095 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3096 } 3097} 3098 3099bool Heap::IsGCRequestPending() const { 3100 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3101} 3102 3103void Heap::RunFinalization(JNIEnv* env) { 3104 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3105 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3106 CHECK(WellKnownClasses::java_lang_System != nullptr); 3107 WellKnownClasses::java_lang_System_runFinalization = 3108 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3109 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3110 } 3111 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3112 WellKnownClasses::java_lang_System_runFinalization); 3113} 3114 3115void Heap::RegisterNativeAllocation(JNIEnv* env, size_t bytes) { 3116 Thread* self = ThreadForEnv(env); 3117 if (native_need_to_run_finalization_) { 3118 RunFinalization(env); 3119 UpdateMaxNativeFootprint(); 3120 native_need_to_run_finalization_ = false; 3121 } 3122 // Total number of native bytes allocated. 3123 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3124 new_native_bytes_allocated += bytes; 3125 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3126 collector::GcType gc_type = HasZygoteSpace() ? collector::kGcTypePartial : 3127 collector::kGcTypeFull; 3128 3129 // The second watermark is higher than the gc watermark. If you hit this it means you are 3130 // allocating native objects faster than the GC can keep up with. 3131 if (new_native_bytes_allocated > growth_limit_) { 3132 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3133 // Just finished a GC, attempt to run finalizers. 3134 RunFinalization(env); 3135 CHECK(!env->ExceptionCheck()); 3136 } 3137 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3138 if (new_native_bytes_allocated > growth_limit_) { 3139 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3140 RunFinalization(env); 3141 native_need_to_run_finalization_ = false; 3142 CHECK(!env->ExceptionCheck()); 3143 } 3144 // We have just run finalizers, update the native watermark since it is very likely that 3145 // finalizers released native managed allocations. 3146 UpdateMaxNativeFootprint(); 3147 } else if (!IsGCRequestPending()) { 3148 if (IsGcConcurrent()) { 3149 RequestConcurrentGC(self); 3150 } else { 3151 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3152 } 3153 } 3154 } 3155} 3156 3157void Heap::RegisterNativeFree(JNIEnv* env, size_t bytes) { 3158 size_t expected_size; 3159 do { 3160 expected_size = native_bytes_allocated_.LoadRelaxed(); 3161 if (UNLIKELY(bytes > expected_size)) { 3162 ScopedObjectAccess soa(env); 3163 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3164 StringPrintf("Attempted to free %zd native bytes with only %zd native bytes " 3165 "registered as allocated", bytes, expected_size).c_str()); 3166 break; 3167 } 3168 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, 3169 expected_size - bytes)); 3170} 3171 3172size_t Heap::GetTotalMemory() const { 3173 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3174} 3175 3176void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3177 DCHECK(mod_union_table != nullptr); 3178 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3179} 3180 3181void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3182 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3183 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3184 CHECK_GE(byte_count, sizeof(mirror::Object)); 3185} 3186 3187void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3188 CHECK(remembered_set != nullptr); 3189 space::Space* space = remembered_set->GetSpace(); 3190 CHECK(space != nullptr); 3191 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3192 remembered_sets_.Put(space, remembered_set); 3193 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3194} 3195 3196void Heap::RemoveRememberedSet(space::Space* space) { 3197 CHECK(space != nullptr); 3198 auto it = remembered_sets_.find(space); 3199 CHECK(it != remembered_sets_.end()); 3200 delete it->second; 3201 remembered_sets_.erase(it); 3202 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3203} 3204 3205void Heap::ClearMarkedObjects() { 3206 // Clear all of the spaces' mark bitmaps. 3207 for (const auto& space : GetContinuousSpaces()) { 3208 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3209 if (space->GetLiveBitmap() != mark_bitmap) { 3210 mark_bitmap->Clear(); 3211 } 3212 } 3213 // Clear the marked objects in the discontinous space object sets. 3214 for (const auto& space : GetDiscontinuousSpaces()) { 3215 space->GetMarkBitmap()->Clear(); 3216 } 3217} 3218 3219} // namespace gc 3220} // namespace art 3221