heap.cc revision c5d085c955244be1743c33227384e5b62076b8bd
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <memory> 24#include <vector> 25 26#include "base/allocator.h" 27#include "base/histogram-inl.h" 28#include "base/stl_util.h" 29#include "common_throws.h" 30#include "cutils/sched_policy.h" 31#include "debugger.h" 32#include "gc/accounting/atomic_stack.h" 33#include "gc/accounting/card_table-inl.h" 34#include "gc/accounting/heap_bitmap-inl.h" 35#include "gc/accounting/mod_union_table.h" 36#include "gc/accounting/mod_union_table-inl.h" 37#include "gc/accounting/remembered_set.h" 38#include "gc/accounting/space_bitmap-inl.h" 39#include "gc/collector/concurrent_copying.h" 40#include "gc/collector/mark_compact.h" 41#include "gc/collector/mark_sweep-inl.h" 42#include "gc/collector/partial_mark_sweep.h" 43#include "gc/collector/semi_space.h" 44#include "gc/collector/sticky_mark_sweep.h" 45#include "gc/reference_processor.h" 46#include "gc/space/bump_pointer_space.h" 47#include "gc/space/dlmalloc_space-inl.h" 48#include "gc/space/image_space.h" 49#include "gc/space/large_object_space.h" 50#include "gc/space/rosalloc_space-inl.h" 51#include "gc/space/space-inl.h" 52#include "gc/space/zygote_space.h" 53#include "entrypoints/quick/quick_alloc_entrypoints.h" 54#include "heap-inl.h" 55#include "image.h" 56#include "intern_table.h" 57#include "mirror/art_field-inl.h" 58#include "mirror/class-inl.h" 59#include "mirror/object.h" 60#include "mirror/object-inl.h" 61#include "mirror/object_array-inl.h" 62#include "mirror/reference-inl.h" 63#include "os.h" 64#include "reflection.h" 65#include "runtime.h" 66#include "ScopedLocalRef.h" 67#include "scoped_thread_state_change.h" 68#include "handle_scope-inl.h" 69#include "thread_list.h" 70#include "well_known_classes.h" 71 72namespace art { 73 74namespace gc { 75 76static constexpr size_t kCollectorTransitionStressIterations = 0; 77static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 78static constexpr bool kGCALotMode = false; 79static constexpr size_t kGcAlotInterval = KB; 80// Minimum amount of remaining bytes before a concurrent GC is triggered. 81static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 82static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 83// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 84// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 85// threads (lower pauses, use less memory bandwidth). 86static constexpr double kStickyGcThroughputAdjustment = 1.0; 87// Whether or not we use the free list large object space. Only use it if USE_ART_LOW_4G_ALLOCATOR 88// since this means that we have to use the slow msync loop in MemMap::MapAnonymous. 89#if USE_ART_LOW_4G_ALLOCATOR 90static constexpr bool kUseFreeListSpaceForLOS = true; 91#else 92static constexpr bool kUseFreeListSpaceForLOS = false; 93#endif 94// Whether or not we compact the zygote in PreZygoteFork. 95static constexpr bool kCompactZygote = kMovingCollector; 96// How many reserve entries are at the end of the allocation stack, these are only needed if the 97// allocation stack overflows. 98static constexpr size_t kAllocationStackReserveSize = 1024; 99// Default mark stack size in bytes. 100static const size_t kDefaultMarkStackSize = 64 * KB; 101// Define space name. 102static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 103static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 104static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 105static const char* kNonMovingSpaceName = "non moving space"; 106static const char* kZygoteSpaceName = "zygote space"; 107static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 108 109Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 110 double target_utilization, double foreground_heap_growth_multiplier, 111 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 112 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 113 CollectorType background_collector_type, size_t parallel_gc_threads, 114 size_t conc_gc_threads, bool low_memory_mode, 115 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 116 bool ignore_max_footprint, bool use_tlab, 117 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 118 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 119 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 120 uint64_t min_interval_homogeneous_space_compaction_by_oom) 121 : non_moving_space_(nullptr), 122 rosalloc_space_(nullptr), 123 dlmalloc_space_(nullptr), 124 main_space_(nullptr), 125 collector_type_(kCollectorTypeNone), 126 foreground_collector_type_(foreground_collector_type), 127 background_collector_type_(background_collector_type), 128 desired_collector_type_(foreground_collector_type_), 129 heap_trim_request_lock_(nullptr), 130 last_trim_time_(0), 131 heap_transition_or_trim_target_time_(0), 132 heap_trim_request_pending_(false), 133 parallel_gc_threads_(parallel_gc_threads), 134 conc_gc_threads_(conc_gc_threads), 135 low_memory_mode_(low_memory_mode), 136 long_pause_log_threshold_(long_pause_log_threshold), 137 long_gc_log_threshold_(long_gc_log_threshold), 138 ignore_max_footprint_(ignore_max_footprint), 139 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 140 have_zygote_space_(false), 141 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 142 collector_type_running_(kCollectorTypeNone), 143 last_gc_type_(collector::kGcTypeNone), 144 next_gc_type_(collector::kGcTypePartial), 145 capacity_(capacity), 146 growth_limit_(growth_limit), 147 max_allowed_footprint_(initial_size), 148 native_footprint_gc_watermark_(initial_size), 149 native_need_to_run_finalization_(false), 150 // Initially assume we perceive jank in case the process state is never updated. 151 process_state_(kProcessStateJankPerceptible), 152 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 153 total_bytes_freed_ever_(0), 154 total_objects_freed_ever_(0), 155 num_bytes_allocated_(0), 156 native_bytes_allocated_(0), 157 verify_missing_card_marks_(false), 158 verify_system_weaks_(false), 159 verify_pre_gc_heap_(verify_pre_gc_heap), 160 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 161 verify_post_gc_heap_(verify_post_gc_heap), 162 verify_mod_union_table_(false), 163 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 164 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 165 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 166 last_gc_time_ns_(NanoTime()), 167 allocation_rate_(0), 168 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 169 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 170 * verification is enabled, we limit the size of allocation stacks to speed up their 171 * searching. 172 */ 173 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 174 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 175 current_allocator_(kAllocatorTypeDlMalloc), 176 current_non_moving_allocator_(kAllocatorTypeNonMoving), 177 bump_pointer_space_(nullptr), 178 temp_space_(nullptr), 179 min_free_(min_free), 180 max_free_(max_free), 181 target_utilization_(target_utilization), 182 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 183 total_wait_time_(0), 184 total_allocation_time_(0), 185 verify_object_mode_(kVerifyObjectModeDisabled), 186 disable_moving_gc_count_(0), 187 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 188 use_tlab_(use_tlab), 189 main_space_backup_(nullptr), 190 min_interval_homogeneous_space_compaction_by_oom_( 191 min_interval_homogeneous_space_compaction_by_oom), 192 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 193 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 194 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 195 LOG(INFO) << "Heap() entering"; 196 } 197 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 198 // entrypoints. 199 const bool is_zygote = Runtime::Current()->IsZygote(); 200 if (!is_zygote) { 201 large_object_threshold_ = kDefaultLargeObjectThreshold; 202 // Background compaction is currently not supported for command line runs. 203 if (background_collector_type_ != foreground_collector_type_) { 204 VLOG(heap) << "Disabling background compaction for non zygote"; 205 background_collector_type_ = foreground_collector_type_; 206 } 207 } 208 ChangeCollector(desired_collector_type_); 209 live_bitmap_.reset(new accounting::HeapBitmap(this)); 210 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 211 // Requested begin for the alloc space, to follow the mapped image and oat files 212 byte* requested_alloc_space_begin = nullptr; 213 if (!image_file_name.empty()) { 214 std::string error_msg; 215 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 216 image_instruction_set, 217 &error_msg); 218 if (image_space != nullptr) { 219 AddSpace(image_space); 220 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 221 // isn't going to get in the middle 222 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 223 CHECK_GT(oat_file_end_addr, image_space->End()); 224 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 225 } else { 226 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 227 << "Attempting to fall back to imageless running. Error was: " << error_msg; 228 } 229 } 230 /* 231 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 232 +- nonmoving space (non_moving_space_capacity)+- 233 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 234 +-????????????????????????????????????????????+- 235 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 236 +-main alloc space / bump space 1 (capacity_) +- 237 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 238 +-????????????????????????????????????????????+- 239 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 240 +-main alloc space2 / bump space 2 (capacity_)+- 241 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 242 */ 243 // We don't have hspace compaction enabled with GSS. 244 if (foreground_collector_type_ == kCollectorTypeGSS) { 245 use_homogeneous_space_compaction_for_oom_ = false; 246 } 247 bool support_homogeneous_space_compaction = 248 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 249 use_homogeneous_space_compaction_for_oom_; 250 // We may use the same space the main space for the non moving space if we don't need to compact 251 // from the main space. 252 // This is not the case if we support homogeneous compaction or have a moving background 253 // collector type. 254 bool separate_non_moving_space = is_zygote || 255 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 256 IsMovingGc(background_collector_type_); 257 if (foreground_collector_type == kCollectorTypeGSS) { 258 separate_non_moving_space = false; 259 } 260 std::unique_ptr<MemMap> main_mem_map_1; 261 std::unique_ptr<MemMap> main_mem_map_2; 262 byte* request_begin = requested_alloc_space_begin; 263 if (request_begin != nullptr && separate_non_moving_space) { 264 request_begin += non_moving_space_capacity; 265 } 266 std::string error_str; 267 std::unique_ptr<MemMap> non_moving_space_mem_map; 268 if (separate_non_moving_space) { 269 // If we are the zygote, the non moving space becomes the zygote space when we run 270 // PreZygoteFork the first time. In this case, call the map "zygote space" since we can't 271 // rename the mem map later. 272 const char* space_name = is_zygote ? kZygoteSpaceName: kNonMovingSpaceName; 273 // Reserve the non moving mem map before the other two since it needs to be at a specific 274 // address. 275 non_moving_space_mem_map.reset( 276 MemMap::MapAnonymous(space_name, requested_alloc_space_begin, 277 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 278 CHECK(non_moving_space_mem_map != nullptr) << error_str; 279 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 280 request_begin = reinterpret_cast<byte*>(300 * MB); 281 } 282 // Attempt to create 2 mem maps at or after the requested begin. 283 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 284 PROT_READ | PROT_WRITE, &error_str)); 285 CHECK(main_mem_map_1.get() != nullptr) << error_str; 286 if (support_homogeneous_space_compaction || 287 background_collector_type_ == kCollectorTypeSS || 288 foreground_collector_type_ == kCollectorTypeSS) { 289 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 290 capacity_, PROT_READ | PROT_WRITE, 291 &error_str)); 292 CHECK(main_mem_map_2.get() != nullptr) << error_str; 293 } 294 // Create the non moving space first so that bitmaps don't take up the address range. 295 if (separate_non_moving_space) { 296 // Non moving space is always dlmalloc since we currently don't have support for multiple 297 // active rosalloc spaces. 298 const size_t size = non_moving_space_mem_map->Size(); 299 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 300 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 301 initial_size, size, size, false); 302 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 303 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 304 << requested_alloc_space_begin; 305 AddSpace(non_moving_space_); 306 } 307 // Create other spaces based on whether or not we have a moving GC. 308 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 309 // Create bump pointer spaces. 310 // We only to create the bump pointer if the foreground collector is a compacting GC. 311 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 312 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 313 main_mem_map_1.release()); 314 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 315 AddSpace(bump_pointer_space_); 316 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 317 main_mem_map_2.release()); 318 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 319 AddSpace(temp_space_); 320 CHECK(separate_non_moving_space); 321 } else { 322 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 323 CHECK(main_space_ != nullptr); 324 AddSpace(main_space_); 325 if (!separate_non_moving_space) { 326 non_moving_space_ = main_space_; 327 CHECK(!non_moving_space_->CanMoveObjects()); 328 } 329 if (foreground_collector_type_ == kCollectorTypeGSS) { 330 CHECK_EQ(foreground_collector_type_, background_collector_type_); 331 // Create bump pointer spaces instead of a backup space. 332 main_mem_map_2.release(); 333 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 334 kGSSBumpPointerSpaceCapacity, nullptr); 335 CHECK(bump_pointer_space_ != nullptr); 336 AddSpace(bump_pointer_space_); 337 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 338 kGSSBumpPointerSpaceCapacity, nullptr); 339 CHECK(temp_space_ != nullptr); 340 AddSpace(temp_space_); 341 } else if (main_mem_map_2.get() != nullptr) { 342 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 343 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 344 growth_limit_, capacity_, name, true)); 345 CHECK(main_space_backup_.get() != nullptr); 346 // Add the space so its accounted for in the heap_begin and heap_end. 347 AddSpace(main_space_backup_.get()); 348 } 349 } 350 CHECK(non_moving_space_ != nullptr); 351 CHECK(!non_moving_space_->CanMoveObjects()); 352 // Allocate the large object space. 353 if (kUseFreeListSpaceForLOS) { 354 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 355 } else { 356 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 357 } 358 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 359 AddSpace(large_object_space_); 360 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 361 CHECK(!continuous_spaces_.empty()); 362 // Relies on the spaces being sorted. 363 byte* heap_begin = continuous_spaces_.front()->Begin(); 364 byte* heap_end = continuous_spaces_.back()->Limit(); 365 size_t heap_capacity = heap_end - heap_begin; 366 // Remove the main backup space since it slows down the GC to have unused extra spaces. 367 if (main_space_backup_.get() != nullptr) { 368 RemoveSpace(main_space_backup_.get()); 369 } 370 // Allocate the card table. 371 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 372 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 373 // Card cache for now since it makes it easier for us to update the references to the copying 374 // spaces. 375 accounting::ModUnionTable* mod_union_table = 376 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 377 GetImageSpace()); 378 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 379 AddModUnionTable(mod_union_table); 380 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 381 accounting::RememberedSet* non_moving_space_rem_set = 382 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 383 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 384 AddRememberedSet(non_moving_space_rem_set); 385 } 386 // TODO: Count objects in the image space here? 387 num_bytes_allocated_.StoreRelaxed(0); 388 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 389 kDefaultMarkStackSize)); 390 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 391 allocation_stack_.reset(accounting::ObjectStack::Create( 392 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 393 live_stack_.reset(accounting::ObjectStack::Create( 394 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 395 // It's still too early to take a lock because there are no threads yet, but we can create locks 396 // now. We don't create it earlier to make it clear that you can't use locks during heap 397 // initialization. 398 gc_complete_lock_ = new Mutex("GC complete lock"); 399 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 400 *gc_complete_lock_)); 401 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 402 last_gc_size_ = GetBytesAllocated(); 403 if (ignore_max_footprint_) { 404 SetIdealFootprint(std::numeric_limits<size_t>::max()); 405 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 406 } 407 CHECK_NE(max_allowed_footprint_, 0U); 408 // Create our garbage collectors. 409 for (size_t i = 0; i < 2; ++i) { 410 const bool concurrent = i != 0; 411 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 412 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 413 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 414 } 415 if (kMovingCollector) { 416 // TODO: Clean this up. 417 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 418 semi_space_collector_ = new collector::SemiSpace(this, generational, 419 generational ? "generational" : ""); 420 garbage_collectors_.push_back(semi_space_collector_); 421 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 422 garbage_collectors_.push_back(concurrent_copying_collector_); 423 mark_compact_collector_ = new collector::MarkCompact(this); 424 garbage_collectors_.push_back(mark_compact_collector_); 425 } 426 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr) { 427 // Check that there's no gap between the image space and the non moving space so that the 428 // immune region won't break (eg. due to a large object allocated in the gap). 429 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 430 non_moving_space_->GetMemMap()); 431 if (!no_gap) { 432 MemMap::DumpMaps(LOG(ERROR)); 433 LOG(FATAL) << "There's a gap between the image space and the main space"; 434 } 435 } 436 if (running_on_valgrind_) { 437 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 438 } 439 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 440 LOG(INFO) << "Heap() exiting"; 441 } 442} 443 444MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 445 int prot_flags, std::string* out_error_str) { 446 while (true) { 447 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 448 PROT_READ | PROT_WRITE, true, out_error_str); 449 if (map != nullptr || request_begin == nullptr) { 450 return map; 451 } 452 // Retry a second time with no specified request begin. 453 request_begin = nullptr; 454 } 455 return nullptr; 456} 457 458space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 459 size_t growth_limit, size_t capacity, 460 const char* name, bool can_move_objects) { 461 space::MallocSpace* malloc_space = nullptr; 462 if (kUseRosAlloc) { 463 // Create rosalloc space. 464 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 465 initial_size, growth_limit, capacity, 466 low_memory_mode_, can_move_objects); 467 } else { 468 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 469 initial_size, growth_limit, capacity, 470 can_move_objects); 471 } 472 if (collector::SemiSpace::kUseRememberedSet) { 473 accounting::RememberedSet* rem_set = 474 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 475 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 476 AddRememberedSet(rem_set); 477 } 478 CHECK(malloc_space != nullptr) << "Failed to create " << name; 479 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 480 return malloc_space; 481} 482 483void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 484 size_t capacity) { 485 // Is background compaction is enabled? 486 bool can_move_objects = IsMovingGc(background_collector_type_) != 487 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 488 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 489 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 490 // from the main space to the zygote space. If background compaction is enabled, always pass in 491 // that we can move objets. 492 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 493 // After the zygote we want this to be false if we don't have background compaction enabled so 494 // that getting primitive array elements is faster. 495 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 496 can_move_objects = !have_zygote_space_ && foreground_collector_type_ != kCollectorTypeGSS; 497 } 498 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 499 RemoveRememberedSet(main_space_); 500 } 501 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 502 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 503 can_move_objects); 504 SetSpaceAsDefault(main_space_); 505 VLOG(heap) << "Created main space " << main_space_; 506} 507 508void Heap::ChangeAllocator(AllocatorType allocator) { 509 if (current_allocator_ != allocator) { 510 // These two allocators are only used internally and don't have any entrypoints. 511 CHECK_NE(allocator, kAllocatorTypeLOS); 512 CHECK_NE(allocator, kAllocatorTypeNonMoving); 513 current_allocator_ = allocator; 514 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 515 SetQuickAllocEntryPointsAllocator(current_allocator_); 516 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 517 } 518} 519 520void Heap::DisableMovingGc() { 521 if (IsMovingGc(foreground_collector_type_)) { 522 foreground_collector_type_ = kCollectorTypeCMS; 523 } 524 if (IsMovingGc(background_collector_type_)) { 525 background_collector_type_ = foreground_collector_type_; 526 } 527 TransitionCollector(foreground_collector_type_); 528 ThreadList* tl = Runtime::Current()->GetThreadList(); 529 Thread* self = Thread::Current(); 530 ScopedThreadStateChange tsc(self, kSuspended); 531 tl->SuspendAll(); 532 // Something may have caused the transition to fail. 533 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 534 CHECK(main_space_ != nullptr); 535 // The allocation stack may have non movable objects in it. We need to flush it since the GC 536 // can't only handle marking allocation stack objects of one non moving space and one main 537 // space. 538 { 539 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 540 FlushAllocStack(); 541 } 542 main_space_->DisableMovingObjects(); 543 non_moving_space_ = main_space_; 544 CHECK(!non_moving_space_->CanMoveObjects()); 545 } 546 tl->ResumeAll(); 547} 548 549std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 550 if (!IsValidContinuousSpaceObjectAddress(klass)) { 551 return StringPrintf("<non heap address klass %p>", klass); 552 } 553 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 554 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 555 std::string result("["); 556 result += SafeGetClassDescriptor(component_type); 557 return result; 558 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 559 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 560 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 561 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 562 } else { 563 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 564 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 565 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 566 } 567 const DexFile* dex_file = dex_cache->GetDexFile(); 568 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 569 if (class_def_idx == DexFile::kDexNoIndex16) { 570 return "<class def not found>"; 571 } 572 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 573 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 574 return dex_file->GetTypeDescriptor(type_id); 575 } 576} 577 578std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 579 if (obj == nullptr) { 580 return "null"; 581 } 582 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 583 if (klass == nullptr) { 584 return "(class=null)"; 585 } 586 std::string result(SafeGetClassDescriptor(klass)); 587 if (obj->IsClass()) { 588 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 589 } 590 return result; 591} 592 593void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 594 if (obj == nullptr) { 595 stream << "(obj=null)"; 596 return; 597 } 598 if (IsAligned<kObjectAlignment>(obj)) { 599 space::Space* space = nullptr; 600 // Don't use find space since it only finds spaces which actually contain objects instead of 601 // spaces which may contain objects (e.g. cleared bump pointer spaces). 602 for (const auto& cur_space : continuous_spaces_) { 603 if (cur_space->HasAddress(obj)) { 604 space = cur_space; 605 break; 606 } 607 } 608 // Unprotect all the spaces. 609 for (const auto& space : continuous_spaces_) { 610 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 611 } 612 stream << "Object " << obj; 613 if (space != nullptr) { 614 stream << " in space " << *space; 615 } 616 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 617 stream << "\nclass=" << klass; 618 if (klass != nullptr) { 619 stream << " type= " << SafePrettyTypeOf(obj); 620 } 621 // Re-protect the address we faulted on. 622 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 623 } 624} 625 626bool Heap::IsCompilingBoot() const { 627 if (!Runtime::Current()->IsCompiler()) { 628 return false; 629 } 630 for (const auto& space : continuous_spaces_) { 631 if (space->IsImageSpace() || space->IsZygoteSpace()) { 632 return false; 633 } 634 } 635 return true; 636} 637 638bool Heap::HasImageSpace() const { 639 for (const auto& space : continuous_spaces_) { 640 if (space->IsImageSpace()) { 641 return true; 642 } 643 } 644 return false; 645} 646 647void Heap::IncrementDisableMovingGC(Thread* self) { 648 // Need to do this holding the lock to prevent races where the GC is about to run / running when 649 // we attempt to disable it. 650 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 651 MutexLock mu(self, *gc_complete_lock_); 652 ++disable_moving_gc_count_; 653 if (IsMovingGc(collector_type_running_)) { 654 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 655 } 656} 657 658void Heap::DecrementDisableMovingGC(Thread* self) { 659 MutexLock mu(self, *gc_complete_lock_); 660 CHECK_GE(disable_moving_gc_count_, 0U); 661 --disable_moving_gc_count_; 662} 663 664void Heap::UpdateProcessState(ProcessState process_state) { 665 if (process_state_ != process_state) { 666 process_state_ = process_state; 667 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 668 // Start at index 1 to avoid "is always false" warning. 669 // Have iteration 1 always transition the collector. 670 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 671 ? foreground_collector_type_ : background_collector_type_); 672 usleep(kCollectorTransitionStressWait); 673 } 674 if (process_state_ == kProcessStateJankPerceptible) { 675 // Transition back to foreground right away to prevent jank. 676 RequestCollectorTransition(foreground_collector_type_, 0); 677 } else { 678 // Don't delay for debug builds since we may want to stress test the GC. 679 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 680 // special handling which does a homogenous space compaction once but then doesn't transition 681 // the collector. 682 RequestCollectorTransition(background_collector_type_, 683 kIsDebugBuild ? 0 : kCollectorTransitionWait); 684 } 685 } 686} 687 688void Heap::CreateThreadPool() { 689 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 690 if (num_threads != 0) { 691 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 692 } 693} 694 695void Heap::VisitObjects(ObjectCallback callback, void* arg) { 696 Thread* self = Thread::Current(); 697 // GCs can move objects, so don't allow this. 698 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 699 if (bump_pointer_space_ != nullptr) { 700 // Visit objects in bump pointer space. 701 bump_pointer_space_->Walk(callback, arg); 702 } 703 // TODO: Switch to standard begin and end to use ranged a based loop. 704 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 705 it < end; ++it) { 706 mirror::Object* obj = *it; 707 if (obj != nullptr && obj->GetClass() != nullptr) { 708 // Avoid the race condition caused by the object not yet being written into the allocation 709 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 710 // there can be nulls on the allocation stack. 711 callback(obj, arg); 712 } 713 } 714 GetLiveBitmap()->Walk(callback, arg); 715 self->EndAssertNoThreadSuspension(old_cause); 716} 717 718void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 719 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 720 space::ContinuousSpace* space2 = non_moving_space_; 721 // TODO: Generalize this to n bitmaps? 722 CHECK(space1 != nullptr); 723 CHECK(space2 != nullptr); 724 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 725 large_object_space_->GetLiveBitmap(), stack); 726} 727 728void Heap::DeleteThreadPool() { 729 thread_pool_.reset(nullptr); 730} 731 732void Heap::AddSpace(space::Space* space) { 733 CHECK(space != nullptr); 734 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 735 if (space->IsContinuousSpace()) { 736 DCHECK(!space->IsDiscontinuousSpace()); 737 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 738 // Continuous spaces don't necessarily have bitmaps. 739 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 740 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 741 if (live_bitmap != nullptr) { 742 CHECK(mark_bitmap != nullptr); 743 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 744 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 745 } 746 continuous_spaces_.push_back(continuous_space); 747 // Ensure that spaces remain sorted in increasing order of start address. 748 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 749 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 750 return a->Begin() < b->Begin(); 751 }); 752 } else { 753 CHECK(space->IsDiscontinuousSpace()); 754 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 755 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 756 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 757 discontinuous_spaces_.push_back(discontinuous_space); 758 } 759 if (space->IsAllocSpace()) { 760 alloc_spaces_.push_back(space->AsAllocSpace()); 761 } 762} 763 764void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 765 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 766 if (continuous_space->IsDlMallocSpace()) { 767 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 768 } else if (continuous_space->IsRosAllocSpace()) { 769 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 770 } 771} 772 773void Heap::RemoveSpace(space::Space* space) { 774 DCHECK(space != nullptr); 775 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 776 if (space->IsContinuousSpace()) { 777 DCHECK(!space->IsDiscontinuousSpace()); 778 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 779 // Continuous spaces don't necessarily have bitmaps. 780 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 781 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 782 if (live_bitmap != nullptr) { 783 DCHECK(mark_bitmap != nullptr); 784 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 785 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 786 } 787 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 788 DCHECK(it != continuous_spaces_.end()); 789 continuous_spaces_.erase(it); 790 } else { 791 DCHECK(space->IsDiscontinuousSpace()); 792 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 793 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 794 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 795 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 796 discontinuous_space); 797 DCHECK(it != discontinuous_spaces_.end()); 798 discontinuous_spaces_.erase(it); 799 } 800 if (space->IsAllocSpace()) { 801 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 802 DCHECK(it != alloc_spaces_.end()); 803 alloc_spaces_.erase(it); 804 } 805} 806 807void Heap::DumpGcPerformanceInfo(std::ostream& os) { 808 // Dump cumulative timings. 809 os << "Dumping cumulative Gc timings\n"; 810 uint64_t total_duration = 0; 811 // Dump cumulative loggers for each GC type. 812 uint64_t total_paused_time = 0; 813 for (auto& collector : garbage_collectors_) { 814 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 815 const size_t iterations = logger.GetIterations(); 816 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 817 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 818 os << ConstDumpable<CumulativeLogger>(logger); 819 const uint64_t total_ns = logger.GetTotalNs(); 820 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 821 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 822 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 823 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 824 Histogram<uint64_t>::CumulativeData cumulative_data; 825 pause_histogram.CreateHistogram(&cumulative_data); 826 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 827 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 828 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 829 << collector->GetName() << " freed: " << freed_objects 830 << " objects with total size " << PrettySize(freed_bytes) << "\n" 831 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 832 << PrettySize(freed_bytes / seconds) << "/s\n"; 833 total_duration += total_ns; 834 total_paused_time += total_pause_ns; 835 } 836 collector->ResetMeasurements(); 837 } 838 uint64_t allocation_time = 839 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 840 if (total_duration != 0) { 841 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 842 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 843 os << "Mean GC size throughput: " 844 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 845 os << "Mean GC object throughput: " 846 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 847 } 848 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 849 os << "Total number of allocations " << total_objects_allocated << "\n"; 850 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 851 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 852 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 853 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 854 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 855 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 856 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 857 if (kMeasureAllocationTime) { 858 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 859 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 860 << "\n"; 861 } 862 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 863 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 864 BaseMutex::DumpAll(os); 865} 866 867Heap::~Heap() { 868 VLOG(heap) << "Starting ~Heap()"; 869 STLDeleteElements(&garbage_collectors_); 870 // If we don't reset then the mark stack complains in its destructor. 871 allocation_stack_->Reset(); 872 live_stack_->Reset(); 873 STLDeleteValues(&mod_union_tables_); 874 STLDeleteValues(&remembered_sets_); 875 STLDeleteElements(&continuous_spaces_); 876 STLDeleteElements(&discontinuous_spaces_); 877 delete gc_complete_lock_; 878 delete heap_trim_request_lock_; 879 VLOG(heap) << "Finished ~Heap()"; 880} 881 882space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 883 bool fail_ok) const { 884 for (const auto& space : continuous_spaces_) { 885 if (space->Contains(obj)) { 886 return space; 887 } 888 } 889 if (!fail_ok) { 890 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 891 } 892 return NULL; 893} 894 895space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 896 bool fail_ok) const { 897 for (const auto& space : discontinuous_spaces_) { 898 if (space->Contains(obj)) { 899 return space; 900 } 901 } 902 if (!fail_ok) { 903 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 904 } 905 return NULL; 906} 907 908space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 909 space::Space* result = FindContinuousSpaceFromObject(obj, true); 910 if (result != NULL) { 911 return result; 912 } 913 return FindDiscontinuousSpaceFromObject(obj, true); 914} 915 916space::ImageSpace* Heap::GetImageSpace() const { 917 for (const auto& space : continuous_spaces_) { 918 if (space->IsImageSpace()) { 919 return space->AsImageSpace(); 920 } 921 } 922 return NULL; 923} 924 925void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 926 std::ostringstream oss; 927 size_t total_bytes_free = GetFreeMemory(); 928 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 929 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 930 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 931 if (total_bytes_free >= byte_count) { 932 space::AllocSpace* space = nullptr; 933 if (allocator_type == kAllocatorTypeNonMoving) { 934 space = non_moving_space_; 935 } else if (allocator_type == kAllocatorTypeRosAlloc || 936 allocator_type == kAllocatorTypeDlMalloc) { 937 space = main_space_; 938 } else if (allocator_type == kAllocatorTypeBumpPointer || 939 allocator_type == kAllocatorTypeTLAB) { 940 space = bump_pointer_space_; 941 } 942 if (space != nullptr) { 943 space->LogFragmentationAllocFailure(oss, byte_count); 944 } 945 } 946 self->ThrowOutOfMemoryError(oss.str().c_str()); 947} 948 949void Heap::DoPendingTransitionOrTrim() { 950 Thread* self = Thread::Current(); 951 CollectorType desired_collector_type; 952 // Wait until we reach the desired transition time. 953 while (true) { 954 uint64_t wait_time; 955 { 956 MutexLock mu(self, *heap_trim_request_lock_); 957 desired_collector_type = desired_collector_type_; 958 uint64_t current_time = NanoTime(); 959 if (current_time >= heap_transition_or_trim_target_time_) { 960 break; 961 } 962 wait_time = heap_transition_or_trim_target_time_ - current_time; 963 } 964 ScopedThreadStateChange tsc(self, kSleeping); 965 usleep(wait_time / 1000); // Usleep takes microseconds. 966 } 967 // Launch homogeneous space compaction if it is desired. 968 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 969 if (!CareAboutPauseTimes()) { 970 PerformHomogeneousSpaceCompact(); 971 } 972 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 973 desired_collector_type = collector_type_; 974 return; 975 } 976 // Transition the collector if the desired collector type is not the same as the current 977 // collector type. 978 TransitionCollector(desired_collector_type); 979 if (!CareAboutPauseTimes()) { 980 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 981 // about pauses. 982 Runtime* runtime = Runtime::Current(); 983 runtime->GetThreadList()->SuspendAll(); 984 uint64_t start_time = NanoTime(); 985 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 986 VLOG(heap) << "Deflating " << count << " monitors took " 987 << PrettyDuration(NanoTime() - start_time); 988 runtime->GetThreadList()->ResumeAll(); 989 } 990 // Do a heap trim if it is needed. 991 Trim(); 992} 993 994void Heap::Trim() { 995 Thread* self = Thread::Current(); 996 { 997 MutexLock mu(self, *heap_trim_request_lock_); 998 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 999 return; 1000 } 1001 last_trim_time_ = NanoTime(); 1002 heap_trim_request_pending_ = false; 1003 } 1004 { 1005 // Need to do this before acquiring the locks since we don't want to get suspended while 1006 // holding any locks. 1007 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1008 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 1009 // trimming. 1010 MutexLock mu(self, *gc_complete_lock_); 1011 // Ensure there is only one GC at a time. 1012 WaitForGcToCompleteLocked(kGcCauseTrim, self); 1013 collector_type_running_ = kCollectorTypeHeapTrim; 1014 } 1015 uint64_t start_ns = NanoTime(); 1016 // Trim the managed spaces. 1017 uint64_t total_alloc_space_allocated = 0; 1018 uint64_t total_alloc_space_size = 0; 1019 uint64_t managed_reclaimed = 0; 1020 for (const auto& space : continuous_spaces_) { 1021 if (space->IsMallocSpace()) { 1022 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 1023 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 1024 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 1025 // for a long period of time. 1026 managed_reclaimed += malloc_space->Trim(); 1027 } 1028 total_alloc_space_size += malloc_space->Size(); 1029 } 1030 } 1031 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 1032 if (bump_pointer_space_ != nullptr) { 1033 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1034 } 1035 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1036 static_cast<float>(total_alloc_space_size); 1037 uint64_t gc_heap_end_ns = NanoTime(); 1038 // We never move things in the native heap, so we can finish the GC at this point. 1039 FinishGC(self, collector::kGcTypeNone); 1040 size_t native_reclaimed = 0; 1041 // Only trim the native heap if we don't care about pauses. 1042 if (!CareAboutPauseTimes()) { 1043#if defined(USE_DLMALLOC) 1044 // Trim the native heap. 1045 dlmalloc_trim(0); 1046 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1047#elif defined(USE_JEMALLOC) 1048 // Jemalloc does it's own internal trimming. 1049#else 1050 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1051#endif 1052 } 1053 uint64_t end_ns = NanoTime(); 1054 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1055 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1056 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1057 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1058 << "%."; 1059} 1060 1061bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1062 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1063 // taking the lock. 1064 if (obj == nullptr) { 1065 return true; 1066 } 1067 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1068} 1069 1070bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1071 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1072} 1073 1074bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1075 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1076 return false; 1077 } 1078 for (const auto& space : continuous_spaces_) { 1079 if (space->HasAddress(obj)) { 1080 return true; 1081 } 1082 } 1083 return false; 1084} 1085 1086bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1087 bool search_live_stack, bool sorted) { 1088 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1089 return false; 1090 } 1091 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1092 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1093 if (obj == klass) { 1094 // This case happens for java.lang.Class. 1095 return true; 1096 } 1097 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1098 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1099 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1100 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1101 return temp_space_->Contains(obj); 1102 } 1103 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1104 space::DiscontinuousSpace* d_space = nullptr; 1105 if (c_space != nullptr) { 1106 if (c_space->GetLiveBitmap()->Test(obj)) { 1107 return true; 1108 } 1109 } else { 1110 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1111 if (d_space != nullptr) { 1112 if (d_space->GetLiveBitmap()->Test(obj)) { 1113 return true; 1114 } 1115 } 1116 } 1117 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1118 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1119 if (i > 0) { 1120 NanoSleep(MsToNs(10)); 1121 } 1122 if (search_allocation_stack) { 1123 if (sorted) { 1124 if (allocation_stack_->ContainsSorted(obj)) { 1125 return true; 1126 } 1127 } else if (allocation_stack_->Contains(obj)) { 1128 return true; 1129 } 1130 } 1131 1132 if (search_live_stack) { 1133 if (sorted) { 1134 if (live_stack_->ContainsSorted(obj)) { 1135 return true; 1136 } 1137 } else if (live_stack_->Contains(obj)) { 1138 return true; 1139 } 1140 } 1141 } 1142 // We need to check the bitmaps again since there is a race where we mark something as live and 1143 // then clear the stack containing it. 1144 if (c_space != nullptr) { 1145 if (c_space->GetLiveBitmap()->Test(obj)) { 1146 return true; 1147 } 1148 } else { 1149 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1150 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1151 return true; 1152 } 1153 } 1154 return false; 1155} 1156 1157std::string Heap::DumpSpaces() const { 1158 std::ostringstream oss; 1159 DumpSpaces(oss); 1160 return oss.str(); 1161} 1162 1163void Heap::DumpSpaces(std::ostream& stream) const { 1164 for (const auto& space : continuous_spaces_) { 1165 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1166 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1167 stream << space << " " << *space << "\n"; 1168 if (live_bitmap != nullptr) { 1169 stream << live_bitmap << " " << *live_bitmap << "\n"; 1170 } 1171 if (mark_bitmap != nullptr) { 1172 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1173 } 1174 } 1175 for (const auto& space : discontinuous_spaces_) { 1176 stream << space << " " << *space << "\n"; 1177 } 1178} 1179 1180void Heap::VerifyObjectBody(mirror::Object* obj) { 1181 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1182 return; 1183 } 1184 1185 // Ignore early dawn of the universe verifications. 1186 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1187 return; 1188 } 1189 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1190 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1191 CHECK(c != nullptr) << "Null class in object " << obj; 1192 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1193 CHECK(VerifyClassClass(c)); 1194 1195 if (verify_object_mode_ > kVerifyObjectModeFast) { 1196 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1197 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1198 } 1199} 1200 1201void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1202 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1203} 1204 1205void Heap::VerifyHeap() { 1206 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1207 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1208} 1209 1210void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1211 // Use signed comparison since freed bytes can be negative when background compaction foreground 1212 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1213 // free list backed space typically increasing memory footprint due to padding and binning. 1214 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1215 // Note: This relies on 2s complement for handling negative freed_bytes. 1216 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1217 if (Runtime::Current()->HasStatsEnabled()) { 1218 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1219 thread_stats->freed_objects += freed_objects; 1220 thread_stats->freed_bytes += freed_bytes; 1221 // TODO: Do this concurrently. 1222 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1223 global_stats->freed_objects += freed_objects; 1224 global_stats->freed_bytes += freed_bytes; 1225 } 1226} 1227 1228space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1229 for (const auto& space : continuous_spaces_) { 1230 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1231 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1232 return space->AsContinuousSpace()->AsRosAllocSpace(); 1233 } 1234 } 1235 } 1236 return nullptr; 1237} 1238 1239mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1240 size_t alloc_size, size_t* bytes_allocated, 1241 size_t* usable_size, 1242 mirror::Class** klass) { 1243 bool was_default_allocator = allocator == GetCurrentAllocator(); 1244 // Make sure there is no pending exception since we may need to throw an OOME. 1245 self->AssertNoPendingException(); 1246 DCHECK(klass != nullptr); 1247 StackHandleScope<1> hs(self); 1248 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1249 klass = nullptr; // Invalidate for safety. 1250 // The allocation failed. If the GC is running, block until it completes, and then retry the 1251 // allocation. 1252 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1253 if (last_gc != collector::kGcTypeNone) { 1254 // If we were the default allocator but the allocator changed while we were suspended, 1255 // abort the allocation. 1256 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1257 return nullptr; 1258 } 1259 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 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 collector::GcType tried_type = next_gc_type_; 1268 const bool gc_ran = 1269 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1270 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1271 return nullptr; 1272 } 1273 if (gc_ran) { 1274 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1275 usable_size); 1276 if (ptr != nullptr) { 1277 return ptr; 1278 } 1279 } 1280 1281 // Loop through our different Gc types and try to Gc until we get enough free memory. 1282 for (collector::GcType gc_type : gc_plan_) { 1283 if (gc_type == tried_type) { 1284 continue; 1285 } 1286 // Attempt to run the collector, if we succeed, re-try the allocation. 1287 const bool gc_ran = 1288 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1289 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1290 return nullptr; 1291 } 1292 if (gc_ran) { 1293 // Did we free sufficient memory for the allocation to succeed? 1294 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1295 usable_size); 1296 if (ptr != nullptr) { 1297 return ptr; 1298 } 1299 } 1300 } 1301 // Allocations have failed after GCs; this is an exceptional state. 1302 // Try harder, growing the heap if necessary. 1303 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1304 usable_size); 1305 if (ptr != nullptr) { 1306 return ptr; 1307 } 1308 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1309 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1310 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1311 // OOME. 1312 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1313 << " allocation"; 1314 // TODO: Run finalization, but this may cause more allocations to occur. 1315 // We don't need a WaitForGcToComplete here either. 1316 DCHECK(!gc_plan_.empty()); 1317 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1318 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1319 return nullptr; 1320 } 1321 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1322 if (ptr == nullptr) { 1323 const uint64_t current_time = NanoTime(); 1324 switch (allocator) { 1325 case kAllocatorTypeRosAlloc: 1326 // Fall-through. 1327 case kAllocatorTypeDlMalloc: { 1328 if (use_homogeneous_space_compaction_for_oom_ && 1329 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1330 min_interval_homogeneous_space_compaction_by_oom_) { 1331 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1332 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1333 switch (result) { 1334 case HomogeneousSpaceCompactResult::kSuccess: 1335 // If the allocation succeeded, we delayed an oom. 1336 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1337 usable_size); 1338 if (ptr != nullptr) { 1339 count_delayed_oom_++; 1340 } 1341 break; 1342 case HomogeneousSpaceCompactResult::kErrorReject: 1343 // Reject due to disabled moving GC. 1344 break; 1345 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1346 // Throw OOM by default. 1347 break; 1348 default: { 1349 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1350 << static_cast<size_t>(result); 1351 } 1352 } 1353 // Always print that we ran homogeneous space compation since this can cause jank. 1354 VLOG(heap) << "Ran heap homogeneous space compaction, " 1355 << " requested defragmentation " 1356 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1357 << " performed defragmentation " 1358 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1359 << " ignored homogeneous space compaction " 1360 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1361 << " delayed count = " 1362 << count_delayed_oom_.LoadSequentiallyConsistent(); 1363 } 1364 break; 1365 } 1366 case kAllocatorTypeNonMoving: { 1367 // Try to transition the heap if the allocation failure was due to the space being full. 1368 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1369 // If we aren't out of memory then the OOM was probably from the non moving space being 1370 // full. Attempt to disable compaction and turn the main space into a non moving space. 1371 DisableMovingGc(); 1372 // If we are still a moving GC then something must have caused the transition to fail. 1373 if (IsMovingGc(collector_type_)) { 1374 MutexLock mu(self, *gc_complete_lock_); 1375 // If we couldn't disable moving GC, just throw OOME and return null. 1376 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1377 << disable_moving_gc_count_; 1378 } else { 1379 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1380 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1381 usable_size); 1382 } 1383 } 1384 break; 1385 } 1386 default: { 1387 // Do nothing for others allocators. 1388 } 1389 } 1390 } 1391 // If the allocation hasn't succeeded by this point, throw an OOM error. 1392 if (ptr == nullptr) { 1393 ThrowOutOfMemoryError(self, alloc_size, allocator); 1394 } 1395 return ptr; 1396} 1397 1398void Heap::SetTargetHeapUtilization(float target) { 1399 DCHECK_GT(target, 0.0f); // asserted in Java code 1400 DCHECK_LT(target, 1.0f); 1401 target_utilization_ = target; 1402} 1403 1404size_t Heap::GetObjectsAllocated() const { 1405 size_t total = 0; 1406 for (space::AllocSpace* space : alloc_spaces_) { 1407 total += space->GetObjectsAllocated(); 1408 } 1409 return total; 1410} 1411 1412uint64_t Heap::GetObjectsAllocatedEver() const { 1413 return GetObjectsFreedEver() + GetObjectsAllocated(); 1414} 1415 1416uint64_t Heap::GetBytesAllocatedEver() const { 1417 return GetBytesFreedEver() + GetBytesAllocated(); 1418} 1419 1420class InstanceCounter { 1421 public: 1422 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1423 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1424 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1425 } 1426 static void Callback(mirror::Object* obj, void* arg) 1427 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1428 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1429 mirror::Class* instance_class = obj->GetClass(); 1430 CHECK(instance_class != nullptr); 1431 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1432 if (instance_counter->use_is_assignable_from_) { 1433 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1434 ++instance_counter->counts_[i]; 1435 } 1436 } else if (instance_class == instance_counter->classes_[i]) { 1437 ++instance_counter->counts_[i]; 1438 } 1439 } 1440 } 1441 1442 private: 1443 const std::vector<mirror::Class*>& classes_; 1444 bool use_is_assignable_from_; 1445 uint64_t* const counts_; 1446 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1447}; 1448 1449void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1450 uint64_t* counts) { 1451 // Can't do any GC in this function since this may move classes. 1452 Thread* self = Thread::Current(); 1453 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1454 InstanceCounter counter(classes, use_is_assignable_from, counts); 1455 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1456 VisitObjects(InstanceCounter::Callback, &counter); 1457 self->EndAssertNoThreadSuspension(old_cause); 1458} 1459 1460class InstanceCollector { 1461 public: 1462 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1463 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1464 : class_(c), max_count_(max_count), instances_(instances) { 1465 } 1466 static void Callback(mirror::Object* obj, void* arg) 1467 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1468 DCHECK(arg != nullptr); 1469 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1470 mirror::Class* instance_class = obj->GetClass(); 1471 if (instance_class == instance_collector->class_) { 1472 if (instance_collector->max_count_ == 0 || 1473 instance_collector->instances_.size() < instance_collector->max_count_) { 1474 instance_collector->instances_.push_back(obj); 1475 } 1476 } 1477 } 1478 1479 private: 1480 mirror::Class* class_; 1481 uint32_t max_count_; 1482 std::vector<mirror::Object*>& instances_; 1483 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1484}; 1485 1486void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1487 std::vector<mirror::Object*>& instances) { 1488 // Can't do any GC in this function since this may move classes. 1489 Thread* self = Thread::Current(); 1490 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1491 InstanceCollector collector(c, max_count, instances); 1492 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1493 VisitObjects(&InstanceCollector::Callback, &collector); 1494 self->EndAssertNoThreadSuspension(old_cause); 1495} 1496 1497class ReferringObjectsFinder { 1498 public: 1499 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1500 std::vector<mirror::Object*>& referring_objects) 1501 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1502 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1503 } 1504 1505 static void Callback(mirror::Object* obj, void* arg) 1506 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1507 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1508 } 1509 1510 // For bitmap Visit. 1511 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1512 // annotalysis on visitors. 1513 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1514 o->VisitReferences<true>(*this, VoidFunctor()); 1515 } 1516 1517 // For Object::VisitReferences. 1518 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1519 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1520 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1521 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1522 referring_objects_.push_back(obj); 1523 } 1524 } 1525 1526 private: 1527 mirror::Object* object_; 1528 uint32_t max_count_; 1529 std::vector<mirror::Object*>& referring_objects_; 1530 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1531}; 1532 1533void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1534 std::vector<mirror::Object*>& referring_objects) { 1535 // Can't do any GC in this function since this may move the object o. 1536 Thread* self = Thread::Current(); 1537 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1538 ReferringObjectsFinder finder(o, max_count, referring_objects); 1539 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1540 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1541 self->EndAssertNoThreadSuspension(old_cause); 1542} 1543 1544void Heap::CollectGarbage(bool clear_soft_references) { 1545 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1546 // last GC will not have necessarily been cleared. 1547 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1548} 1549 1550HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1551 Thread* self = Thread::Current(); 1552 // Inc requested homogeneous space compaction. 1553 count_requested_homogeneous_space_compaction_++; 1554 // Store performed homogeneous space compaction at a new request arrival. 1555 ThreadList* tl = Runtime::Current()->GetThreadList(); 1556 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1557 Locks::mutator_lock_->AssertNotHeld(self); 1558 { 1559 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1560 MutexLock mu(self, *gc_complete_lock_); 1561 // Ensure there is only one GC at a time. 1562 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1563 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1564 // is non zero. 1565 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1566 // exit. 1567 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1568 !main_space_->CanMoveObjects()) { 1569 return HomogeneousSpaceCompactResult::kErrorReject; 1570 } 1571 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1572 } 1573 if (Runtime::Current()->IsShuttingDown(self)) { 1574 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1575 // cause objects to get finalized. 1576 FinishGC(self, collector::kGcTypeNone); 1577 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1578 } 1579 // Suspend all threads. 1580 tl->SuspendAll(); 1581 uint64_t start_time = NanoTime(); 1582 // Launch compaction. 1583 space::MallocSpace* to_space = main_space_backup_.release(); 1584 space::MallocSpace* from_space = main_space_; 1585 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1586 const uint64_t space_size_before_compaction = from_space->Size(); 1587 AddSpace(to_space); 1588 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1589 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1590 from_space->GetMemMap()->Protect(PROT_READ); 1591 const uint64_t space_size_after_compaction = to_space->Size(); 1592 main_space_ = to_space; 1593 main_space_backup_.reset(from_space); 1594 RemoveSpace(from_space); 1595 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1596 // Update performed homogeneous space compaction count. 1597 count_performed_homogeneous_space_compaction_++; 1598 // Print statics log and resume all threads. 1599 uint64_t duration = NanoTime() - start_time; 1600 VLOG(heap) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1601 << PrettySize(space_size_before_compaction) << " -> " 1602 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1603 << std::fixed << static_cast<double>(space_size_after_compaction) / 1604 static_cast<double>(space_size_before_compaction); 1605 tl->ResumeAll(); 1606 // Finish GC. 1607 reference_processor_.EnqueueClearedReferences(self); 1608 GrowForUtilization(semi_space_collector_); 1609 FinishGC(self, collector::kGcTypeFull); 1610 return HomogeneousSpaceCompactResult::kSuccess; 1611} 1612 1613 1614void Heap::TransitionCollector(CollectorType collector_type) { 1615 if (collector_type == collector_type_) { 1616 return; 1617 } 1618 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1619 << " -> " << static_cast<int>(collector_type); 1620 uint64_t start_time = NanoTime(); 1621 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1622 Runtime* const runtime = Runtime::Current(); 1623 ThreadList* const tl = runtime->GetThreadList(); 1624 Thread* const self = Thread::Current(); 1625 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1626 Locks::mutator_lock_->AssertNotHeld(self); 1627 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1628 // compacting_gc_disable_count_, this should rarely occurs). 1629 for (;;) { 1630 { 1631 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1632 MutexLock mu(self, *gc_complete_lock_); 1633 // Ensure there is only one GC at a time. 1634 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1635 // Currently we only need a heap transition if we switch from a moving collector to a 1636 // non-moving one, or visa versa. 1637 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1638 // If someone else beat us to it and changed the collector before we could, exit. 1639 // This is safe to do before the suspend all since we set the collector_type_running_ before 1640 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1641 // then it would get blocked on WaitForGcToCompleteLocked. 1642 if (collector_type == collector_type_) { 1643 return; 1644 } 1645 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1646 if (!copying_transition || disable_moving_gc_count_ == 0) { 1647 // TODO: Not hard code in semi-space collector? 1648 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1649 break; 1650 } 1651 } 1652 usleep(1000); 1653 } 1654 if (runtime->IsShuttingDown(self)) { 1655 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1656 // cause objects to get finalized. 1657 FinishGC(self, collector::kGcTypeNone); 1658 return; 1659 } 1660 tl->SuspendAll(); 1661 switch (collector_type) { 1662 case kCollectorTypeSS: { 1663 if (!IsMovingGc(collector_type_)) { 1664 // Create the bump pointer space from the backup space. 1665 CHECK(main_space_backup_ != nullptr); 1666 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1667 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1668 // pointer space last transition it will be protected. 1669 CHECK(mem_map != nullptr); 1670 mem_map->Protect(PROT_READ | PROT_WRITE); 1671 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1672 mem_map.release()); 1673 AddSpace(bump_pointer_space_); 1674 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1675 // Use the now empty main space mem map for the bump pointer temp space. 1676 mem_map.reset(main_space_->ReleaseMemMap()); 1677 // Unset the pointers just in case. 1678 if (dlmalloc_space_ == main_space_) { 1679 dlmalloc_space_ = nullptr; 1680 } else if (rosalloc_space_ == main_space_) { 1681 rosalloc_space_ = nullptr; 1682 } 1683 // Remove the main space so that we don't try to trim it, this doens't work for debug 1684 // builds since RosAlloc attempts to read the magic number from a protected page. 1685 RemoveSpace(main_space_); 1686 RemoveRememberedSet(main_space_); 1687 delete main_space_; // Delete the space since it has been removed. 1688 main_space_ = nullptr; 1689 RemoveRememberedSet(main_space_backup_.get()); 1690 main_space_backup_.reset(nullptr); // Deletes the space. 1691 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1692 mem_map.release()); 1693 AddSpace(temp_space_); 1694 } 1695 break; 1696 } 1697 case kCollectorTypeMS: 1698 // Fall through. 1699 case kCollectorTypeCMS: { 1700 if (IsMovingGc(collector_type_)) { 1701 CHECK(temp_space_ != nullptr); 1702 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1703 RemoveSpace(temp_space_); 1704 temp_space_ = nullptr; 1705 mem_map->Protect(PROT_READ | PROT_WRITE); 1706 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1707 mem_map->Size()); 1708 mem_map.release(); 1709 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1710 AddSpace(main_space_); 1711 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1712 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1713 RemoveSpace(bump_pointer_space_); 1714 bump_pointer_space_ = nullptr; 1715 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1716 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1717 if (kIsDebugBuild && kUseRosAlloc) { 1718 mem_map->Protect(PROT_READ | PROT_WRITE); 1719 } 1720 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1721 mem_map->Size(), mem_map->Size(), 1722 name, true)); 1723 if (kIsDebugBuild && kUseRosAlloc) { 1724 mem_map->Protect(PROT_NONE); 1725 } 1726 mem_map.release(); 1727 } 1728 break; 1729 } 1730 default: { 1731 LOG(FATAL) << "Attempted to transition to invalid collector type " 1732 << static_cast<size_t>(collector_type); 1733 break; 1734 } 1735 } 1736 ChangeCollector(collector_type); 1737 tl->ResumeAll(); 1738 // Can't call into java code with all threads suspended. 1739 reference_processor_.EnqueueClearedReferences(self); 1740 uint64_t duration = NanoTime() - start_time; 1741 GrowForUtilization(semi_space_collector_); 1742 FinishGC(self, collector::kGcTypeFull); 1743 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1744 int32_t delta_allocated = before_allocated - after_allocated; 1745 std::string saved_str; 1746 if (delta_allocated >= 0) { 1747 saved_str = " saved at least " + PrettySize(delta_allocated); 1748 } else { 1749 saved_str = " expanded " + PrettySize(-delta_allocated); 1750 } 1751 VLOG(heap) << "Heap transition to " << process_state_ << " took " 1752 << PrettyDuration(duration) << saved_str; 1753} 1754 1755void Heap::ChangeCollector(CollectorType collector_type) { 1756 // TODO: Only do this with all mutators suspended to avoid races. 1757 if (collector_type != collector_type_) { 1758 if (collector_type == kCollectorTypeMC) { 1759 // Don't allow mark compact unless support is compiled in. 1760 CHECK(kMarkCompactSupport); 1761 } 1762 collector_type_ = collector_type; 1763 gc_plan_.clear(); 1764 switch (collector_type_) { 1765 case kCollectorTypeCC: // Fall-through. 1766 case kCollectorTypeMC: // Fall-through. 1767 case kCollectorTypeSS: // Fall-through. 1768 case kCollectorTypeGSS: { 1769 gc_plan_.push_back(collector::kGcTypeFull); 1770 if (use_tlab_) { 1771 ChangeAllocator(kAllocatorTypeTLAB); 1772 } else { 1773 ChangeAllocator(kAllocatorTypeBumpPointer); 1774 } 1775 break; 1776 } 1777 case kCollectorTypeMS: { 1778 gc_plan_.push_back(collector::kGcTypeSticky); 1779 gc_plan_.push_back(collector::kGcTypePartial); 1780 gc_plan_.push_back(collector::kGcTypeFull); 1781 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1782 break; 1783 } 1784 case kCollectorTypeCMS: { 1785 gc_plan_.push_back(collector::kGcTypeSticky); 1786 gc_plan_.push_back(collector::kGcTypePartial); 1787 gc_plan_.push_back(collector::kGcTypeFull); 1788 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1789 break; 1790 } 1791 default: { 1792 LOG(FATAL) << "Unimplemented"; 1793 } 1794 } 1795 if (IsGcConcurrent()) { 1796 concurrent_start_bytes_ = 1797 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1798 } else { 1799 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1800 } 1801 } 1802} 1803 1804// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1805class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1806 public: 1807 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1808 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1809 } 1810 1811 void BuildBins(space::ContinuousSpace* space) { 1812 bin_live_bitmap_ = space->GetLiveBitmap(); 1813 bin_mark_bitmap_ = space->GetMarkBitmap(); 1814 BinContext context; 1815 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1816 context.collector_ = this; 1817 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1818 // Note: This requires traversing the space in increasing order of object addresses. 1819 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1820 // Add the last bin which spans after the last object to the end of the space. 1821 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1822 } 1823 1824 private: 1825 struct BinContext { 1826 uintptr_t prev_; // The end of the previous object. 1827 ZygoteCompactingCollector* collector_; 1828 }; 1829 // Maps from bin sizes to locations. 1830 std::multimap<size_t, uintptr_t> bins_; 1831 // Live bitmap of the space which contains the bins. 1832 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1833 // Mark bitmap of the space which contains the bins. 1834 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1835 1836 static void Callback(mirror::Object* obj, void* arg) 1837 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1838 DCHECK(arg != nullptr); 1839 BinContext* context = reinterpret_cast<BinContext*>(arg); 1840 ZygoteCompactingCollector* collector = context->collector_; 1841 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1842 size_t bin_size = object_addr - context->prev_; 1843 // Add the bin consisting of the end of the previous object to the start of the current object. 1844 collector->AddBin(bin_size, context->prev_); 1845 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1846 } 1847 1848 void AddBin(size_t size, uintptr_t position) { 1849 if (size != 0) { 1850 bins_.insert(std::make_pair(size, position)); 1851 } 1852 } 1853 1854 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1855 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1856 // allocator. 1857 return false; 1858 } 1859 1860 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1861 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1862 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1863 mirror::Object* forward_address; 1864 // Find the smallest bin which we can move obj in. 1865 auto it = bins_.lower_bound(object_size); 1866 if (it == bins_.end()) { 1867 // No available space in the bins, place it in the target space instead (grows the zygote 1868 // space). 1869 size_t bytes_allocated; 1870 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1871 if (to_space_live_bitmap_ != nullptr) { 1872 to_space_live_bitmap_->Set(forward_address); 1873 } else { 1874 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1875 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1876 } 1877 } else { 1878 size_t size = it->first; 1879 uintptr_t pos = it->second; 1880 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1881 forward_address = reinterpret_cast<mirror::Object*>(pos); 1882 // Set the live and mark bits so that sweeping system weaks works properly. 1883 bin_live_bitmap_->Set(forward_address); 1884 bin_mark_bitmap_->Set(forward_address); 1885 DCHECK_GE(size, object_size); 1886 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1887 } 1888 // Copy the object over to its new location. 1889 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1890 if (kUseBakerOrBrooksReadBarrier) { 1891 obj->AssertReadBarrierPointer(); 1892 if (kUseBrooksReadBarrier) { 1893 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1894 forward_address->SetReadBarrierPointer(forward_address); 1895 } 1896 forward_address->AssertReadBarrierPointer(); 1897 } 1898 return forward_address; 1899 } 1900}; 1901 1902void Heap::UnBindBitmaps() { 1903 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1904 for (const auto& space : GetContinuousSpaces()) { 1905 if (space->IsContinuousMemMapAllocSpace()) { 1906 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1907 if (alloc_space->HasBoundBitmaps()) { 1908 alloc_space->UnBindBitmaps(); 1909 } 1910 } 1911 } 1912} 1913 1914void Heap::PreZygoteFork() { 1915 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1916 Thread* self = Thread::Current(); 1917 MutexLock mu(self, zygote_creation_lock_); 1918 // Try to see if we have any Zygote spaces. 1919 if (have_zygote_space_) { 1920 return; 1921 } 1922 Runtime::Current()->GetInternTable()->SwapPostZygoteWithPreZygote(); 1923 Runtime::Current()->GetClassLinker()->MoveClassTableToPreZygote(); 1924 VLOG(heap) << "Starting PreZygoteFork"; 1925 // Trim the pages at the end of the non moving space. 1926 non_moving_space_->Trim(); 1927 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1928 // there. 1929 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1930 const bool same_space = non_moving_space_ == main_space_; 1931 if (kCompactZygote) { 1932 // Can't compact if the non moving space is the same as the main space. 1933 DCHECK(semi_space_collector_ != nullptr); 1934 // Temporarily disable rosalloc verification because the zygote 1935 // compaction will mess up the rosalloc internal metadata. 1936 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1937 ZygoteCompactingCollector zygote_collector(this); 1938 zygote_collector.BuildBins(non_moving_space_); 1939 // Create a new bump pointer space which we will compact into. 1940 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1941 non_moving_space_->Limit()); 1942 // Compact the bump pointer space to a new zygote bump pointer space. 1943 bool reset_main_space = false; 1944 if (IsMovingGc(collector_type_)) { 1945 zygote_collector.SetFromSpace(bump_pointer_space_); 1946 } else { 1947 CHECK(main_space_ != nullptr); 1948 // Copy from the main space. 1949 zygote_collector.SetFromSpace(main_space_); 1950 reset_main_space = true; 1951 } 1952 zygote_collector.SetToSpace(&target_space); 1953 zygote_collector.SetSwapSemiSpaces(false); 1954 zygote_collector.Run(kGcCauseCollectorTransition, false); 1955 if (reset_main_space) { 1956 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1957 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1958 MemMap* mem_map = main_space_->ReleaseMemMap(); 1959 RemoveSpace(main_space_); 1960 space::Space* old_main_space = main_space_; 1961 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1962 delete old_main_space; 1963 AddSpace(main_space_); 1964 } else { 1965 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1966 } 1967 if (temp_space_ != nullptr) { 1968 CHECK(temp_space_->IsEmpty()); 1969 } 1970 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1971 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1972 // Update the end and write out image. 1973 non_moving_space_->SetEnd(target_space.End()); 1974 non_moving_space_->SetLimit(target_space.Limit()); 1975 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1976 } 1977 // Change the collector to the post zygote one. 1978 ChangeCollector(foreground_collector_type_); 1979 // Save the old space so that we can remove it after we complete creating the zygote space. 1980 space::MallocSpace* old_alloc_space = non_moving_space_; 1981 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1982 // the remaining available space. 1983 // Remove the old space before creating the zygote space since creating the zygote space sets 1984 // the old alloc space's bitmaps to nullptr. 1985 RemoveSpace(old_alloc_space); 1986 if (collector::SemiSpace::kUseRememberedSet) { 1987 // Sanity bound check. 1988 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1989 // Remove the remembered set for the now zygote space (the old 1990 // non-moving space). Note now that we have compacted objects into 1991 // the zygote space, the data in the remembered set is no longer 1992 // needed. The zygote space will instead have a mod-union table 1993 // from this point on. 1994 RemoveRememberedSet(old_alloc_space); 1995 } 1996 // Remaining space becomes the new non moving space. 1997 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace(kNonMovingSpaceName, 1998 low_memory_mode_, 1999 &non_moving_space_); 2000 CHECK(!non_moving_space_->CanMoveObjects()); 2001 if (same_space) { 2002 main_space_ = non_moving_space_; 2003 SetSpaceAsDefault(main_space_); 2004 } 2005 delete old_alloc_space; 2006 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 2007 AddSpace(zygote_space); 2008 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 2009 AddSpace(non_moving_space_); 2010 have_zygote_space_ = true; 2011 // Enable large object space allocations. 2012 large_object_threshold_ = kDefaultLargeObjectThreshold; 2013 // Create the zygote space mod union table. 2014 accounting::ModUnionTable* mod_union_table = 2015 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 2016 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 2017 AddModUnionTable(mod_union_table); 2018 if (collector::SemiSpace::kUseRememberedSet) { 2019 // Add a new remembered set for the post-zygote non-moving space. 2020 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 2021 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 2022 non_moving_space_); 2023 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 2024 << "Failed to create post-zygote non-moving space remembered set"; 2025 AddRememberedSet(post_zygote_non_moving_space_rem_set); 2026 } 2027} 2028 2029void Heap::FlushAllocStack() { 2030 MarkAllocStackAsLive(allocation_stack_.get()); 2031 allocation_stack_->Reset(); 2032} 2033 2034void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2035 accounting::ContinuousSpaceBitmap* bitmap2, 2036 accounting::LargeObjectBitmap* large_objects, 2037 accounting::ObjectStack* stack) { 2038 DCHECK(bitmap1 != nullptr); 2039 DCHECK(bitmap2 != nullptr); 2040 mirror::Object** limit = stack->End(); 2041 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2042 const mirror::Object* obj = *it; 2043 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2044 if (bitmap1->HasAddress(obj)) { 2045 bitmap1->Set(obj); 2046 } else if (bitmap2->HasAddress(obj)) { 2047 bitmap2->Set(obj); 2048 } else { 2049 large_objects->Set(obj); 2050 } 2051 } 2052 } 2053} 2054 2055void Heap::SwapSemiSpaces() { 2056 CHECK(bump_pointer_space_ != nullptr); 2057 CHECK(temp_space_ != nullptr); 2058 std::swap(bump_pointer_space_, temp_space_); 2059} 2060 2061void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2062 space::ContinuousMemMapAllocSpace* source_space, 2063 GcCause gc_cause) { 2064 CHECK(kMovingCollector); 2065 if (target_space != source_space) { 2066 // Don't swap spaces since this isn't a typical semi space collection. 2067 semi_space_collector_->SetSwapSemiSpaces(false); 2068 semi_space_collector_->SetFromSpace(source_space); 2069 semi_space_collector_->SetToSpace(target_space); 2070 semi_space_collector_->Run(gc_cause, false); 2071 } else { 2072 CHECK(target_space->IsBumpPointerSpace()) 2073 << "In-place compaction is only supported for bump pointer spaces"; 2074 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2075 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2076 } 2077} 2078 2079collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2080 bool clear_soft_references) { 2081 Thread* self = Thread::Current(); 2082 Runtime* runtime = Runtime::Current(); 2083 // If the heap can't run the GC, silently fail and return that no GC was run. 2084 switch (gc_type) { 2085 case collector::kGcTypePartial: { 2086 if (!have_zygote_space_) { 2087 return collector::kGcTypeNone; 2088 } 2089 break; 2090 } 2091 default: { 2092 // Other GC types don't have any special cases which makes them not runnable. The main case 2093 // here is full GC. 2094 } 2095 } 2096 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2097 Locks::mutator_lock_->AssertNotHeld(self); 2098 if (self->IsHandlingStackOverflow()) { 2099 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2100 } 2101 bool compacting_gc; 2102 { 2103 gc_complete_lock_->AssertNotHeld(self); 2104 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2105 MutexLock mu(self, *gc_complete_lock_); 2106 // Ensure there is only one GC at a time. 2107 WaitForGcToCompleteLocked(gc_cause, self); 2108 compacting_gc = IsMovingGc(collector_type_); 2109 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2110 if (compacting_gc && disable_moving_gc_count_ != 0) { 2111 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2112 return collector::kGcTypeNone; 2113 } 2114 collector_type_running_ = collector_type_; 2115 } 2116 2117 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2118 ++runtime->GetStats()->gc_for_alloc_count; 2119 ++self->GetStats()->gc_for_alloc_count; 2120 } 2121 uint64_t gc_start_time_ns = NanoTime(); 2122 uint64_t gc_start_size = GetBytesAllocated(); 2123 // Approximate allocation rate in bytes / second. 2124 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2125 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2126 if (LIKELY(ms_delta != 0)) { 2127 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2128 ATRACE_INT("Allocation rate KB/s", allocation_rate_ / KB); 2129 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2130 } 2131 2132 DCHECK_LT(gc_type, collector::kGcTypeMax); 2133 DCHECK_NE(gc_type, collector::kGcTypeNone); 2134 2135 collector::GarbageCollector* collector = nullptr; 2136 // TODO: Clean this up. 2137 if (compacting_gc) { 2138 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2139 current_allocator_ == kAllocatorTypeTLAB); 2140 switch (collector_type_) { 2141 case kCollectorTypeSS: 2142 // Fall-through. 2143 case kCollectorTypeGSS: 2144 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2145 semi_space_collector_->SetToSpace(temp_space_); 2146 semi_space_collector_->SetSwapSemiSpaces(true); 2147 collector = semi_space_collector_; 2148 break; 2149 case kCollectorTypeCC: 2150 collector = concurrent_copying_collector_; 2151 break; 2152 case kCollectorTypeMC: 2153 mark_compact_collector_->SetSpace(bump_pointer_space_); 2154 collector = mark_compact_collector_; 2155 break; 2156 default: 2157 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2158 } 2159 if (collector != mark_compact_collector_) { 2160 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2161 CHECK(temp_space_->IsEmpty()); 2162 } 2163 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2164 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2165 current_allocator_ == kAllocatorTypeDlMalloc) { 2166 collector = FindCollectorByGcType(gc_type); 2167 } else { 2168 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2169 } 2170 if (IsGcConcurrent()) { 2171 // Disable concurrent GC check so that we don't have spammy JNI requests. 2172 // This gets recalculated in GrowForUtilization. It is important that it is disabled / 2173 // calculated in the same thread so that there aren't any races that can cause it to become 2174 // permanantly disabled. b/17942071 2175 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2176 } 2177 CHECK(collector != nullptr) 2178 << "Could not find garbage collector with collector_type=" 2179 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2180 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2181 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2182 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2183 RequestHeapTrim(); 2184 // Enqueue cleared references. 2185 reference_processor_.EnqueueClearedReferences(self); 2186 // Grow the heap so that we know when to perform the next GC. 2187 GrowForUtilization(collector); 2188 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2189 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2190 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2191 // (mutator time blocked >= long_pause_log_threshold_). 2192 bool log_gc = gc_cause == kGcCauseExplicit; 2193 if (!log_gc && CareAboutPauseTimes()) { 2194 // GC for alloc pauses the allocating thread, so consider it as a pause. 2195 log_gc = duration > long_gc_log_threshold_ || 2196 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2197 for (uint64_t pause : pause_times) { 2198 log_gc = log_gc || pause >= long_pause_log_threshold_; 2199 } 2200 } 2201 if (log_gc) { 2202 const size_t percent_free = GetPercentFree(); 2203 const size_t current_heap_size = GetBytesAllocated(); 2204 const size_t total_memory = GetTotalMemory(); 2205 std::ostringstream pause_string; 2206 for (size_t i = 0; i < pause_times.size(); ++i) { 2207 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2208 << ((i != pause_times.size() - 1) ? "," : ""); 2209 } 2210 LOG(INFO) << gc_cause << " " << collector->GetName() 2211 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2212 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2213 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2214 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2215 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2216 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2217 << " total " << PrettyDuration((duration / 1000) * 1000); 2218 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2219 } 2220 FinishGC(self, gc_type); 2221 // Inform DDMS that a GC completed. 2222 Dbg::GcDidFinish(); 2223 return gc_type; 2224} 2225 2226void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2227 MutexLock mu(self, *gc_complete_lock_); 2228 collector_type_running_ = kCollectorTypeNone; 2229 if (gc_type != collector::kGcTypeNone) { 2230 last_gc_type_ = gc_type; 2231 } 2232 // Wake anyone who may have been waiting for the GC to complete. 2233 gc_complete_cond_->Broadcast(self); 2234} 2235 2236static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2237 RootType /*root_type*/) { 2238 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2239 if (*root == obj) { 2240 LOG(INFO) << "Object " << obj << " is a root"; 2241 } 2242} 2243 2244class ScanVisitor { 2245 public: 2246 void operator()(const mirror::Object* obj) const { 2247 LOG(ERROR) << "Would have rescanned object " << obj; 2248 } 2249}; 2250 2251// Verify a reference from an object. 2252class VerifyReferenceVisitor { 2253 public: 2254 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2255 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2256 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2257 2258 size_t GetFailureCount() const { 2259 return fail_count_->LoadSequentiallyConsistent(); 2260 } 2261 2262 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2263 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2264 if (verify_referent_) { 2265 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2266 } 2267 } 2268 2269 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2270 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2271 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2272 } 2273 2274 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2275 return heap_->IsLiveObjectLocked(obj, true, false, true); 2276 } 2277 2278 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2279 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2280 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2281 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2282 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2283 << " thread_id= " << thread_id << " root_type= " << root_type; 2284 } 2285 } 2286 2287 private: 2288 // TODO: Fix the no thread safety analysis. 2289 // Returns false on failure. 2290 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2291 NO_THREAD_SAFETY_ANALYSIS { 2292 if (ref == nullptr || IsLive(ref)) { 2293 // Verify that the reference is live. 2294 return true; 2295 } 2296 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2297 // Print message on only on first failure to prevent spam. 2298 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2299 } 2300 if (obj != nullptr) { 2301 // Only do this part for non roots. 2302 accounting::CardTable* card_table = heap_->GetCardTable(); 2303 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2304 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2305 byte* card_addr = card_table->CardFromAddr(obj); 2306 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2307 << offset << "\n card value = " << static_cast<int>(*card_addr); 2308 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2309 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2310 } else { 2311 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2312 } 2313 2314 // Attempt to find the class inside of the recently freed objects. 2315 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2316 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2317 space::MallocSpace* space = ref_space->AsMallocSpace(); 2318 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2319 if (ref_class != nullptr) { 2320 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2321 << PrettyClass(ref_class); 2322 } else { 2323 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2324 } 2325 } 2326 2327 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2328 ref->GetClass()->IsClass()) { 2329 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2330 } else { 2331 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2332 << ") is not a valid heap address"; 2333 } 2334 2335 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2336 void* cover_begin = card_table->AddrFromCard(card_addr); 2337 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2338 accounting::CardTable::kCardSize); 2339 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2340 << "-" << cover_end; 2341 accounting::ContinuousSpaceBitmap* bitmap = 2342 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2343 2344 if (bitmap == nullptr) { 2345 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2346 if (!VerifyClassClass(obj->GetClass())) { 2347 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2348 } 2349 } else { 2350 // Print out how the object is live. 2351 if (bitmap->Test(obj)) { 2352 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2353 } 2354 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2355 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2356 } 2357 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2358 LOG(ERROR) << "Object " << obj << " found in live stack"; 2359 } 2360 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2361 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2362 } 2363 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2364 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2365 } 2366 // Attempt to see if the card table missed the reference. 2367 ScanVisitor scan_visitor; 2368 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2369 card_table->Scan(bitmap, byte_cover_begin, 2370 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2371 } 2372 2373 // Search to see if any of the roots reference our object. 2374 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2375 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2376 2377 // Search to see if any of the roots reference our reference. 2378 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2379 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2380 } 2381 return false; 2382 } 2383 2384 Heap* const heap_; 2385 Atomic<size_t>* const fail_count_; 2386 const bool verify_referent_; 2387}; 2388 2389// Verify all references within an object, for use with HeapBitmap::Visit. 2390class VerifyObjectVisitor { 2391 public: 2392 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2393 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2394 } 2395 2396 void operator()(mirror::Object* obj) const 2397 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2398 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2399 // be live or else how did we find it in the live bitmap? 2400 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2401 // The class doesn't count as a reference but we should verify it anyways. 2402 obj->VisitReferences<true>(visitor, visitor); 2403 } 2404 2405 static void VisitCallback(mirror::Object* obj, void* arg) 2406 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2407 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2408 visitor->operator()(obj); 2409 } 2410 2411 size_t GetFailureCount() const { 2412 return fail_count_->LoadSequentiallyConsistent(); 2413 } 2414 2415 private: 2416 Heap* const heap_; 2417 Atomic<size_t>* const fail_count_; 2418 const bool verify_referent_; 2419}; 2420 2421void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2422 // Slow path, the allocation stack push back must have already failed. 2423 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2424 do { 2425 // TODO: Add handle VerifyObject. 2426 StackHandleScope<1> hs(self); 2427 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2428 // Push our object into the reserve region of the allocaiton stack. This is only required due 2429 // to heap verification requiring that roots are live (either in the live bitmap or in the 2430 // allocation stack). 2431 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2432 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2433 } while (!allocation_stack_->AtomicPushBack(*obj)); 2434} 2435 2436void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2437 // Slow path, the allocation stack push back must have already failed. 2438 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2439 mirror::Object** start_address; 2440 mirror::Object** end_address; 2441 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2442 &end_address)) { 2443 // TODO: Add handle VerifyObject. 2444 StackHandleScope<1> hs(self); 2445 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2446 // Push our object into the reserve region of the allocaiton stack. This is only required due 2447 // to heap verification requiring that roots are live (either in the live bitmap or in the 2448 // allocation stack). 2449 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2450 // Push into the reserve allocation stack. 2451 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2452 } 2453 self->SetThreadLocalAllocationStack(start_address, end_address); 2454 // Retry on the new thread-local allocation stack. 2455 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2456} 2457 2458// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2459size_t Heap::VerifyHeapReferences(bool verify_referents) { 2460 Thread* self = Thread::Current(); 2461 Locks::mutator_lock_->AssertExclusiveHeld(self); 2462 // Lets sort our allocation stacks so that we can efficiently binary search them. 2463 allocation_stack_->Sort(); 2464 live_stack_->Sort(); 2465 // Since we sorted the allocation stack content, need to revoke all 2466 // thread-local allocation stacks. 2467 RevokeAllThreadLocalAllocationStacks(self); 2468 Atomic<size_t> fail_count_(0); 2469 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2470 // Verify objects in the allocation stack since these will be objects which were: 2471 // 1. Allocated prior to the GC (pre GC verification). 2472 // 2. Allocated during the GC (pre sweep GC verification). 2473 // We don't want to verify the objects in the live stack since they themselves may be 2474 // pointing to dead objects if they are not reachable. 2475 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2476 // Verify the roots: 2477 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2478 if (visitor.GetFailureCount() > 0) { 2479 // Dump mod-union tables. 2480 for (const auto& table_pair : mod_union_tables_) { 2481 accounting::ModUnionTable* mod_union_table = table_pair.second; 2482 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2483 } 2484 // Dump remembered sets. 2485 for (const auto& table_pair : remembered_sets_) { 2486 accounting::RememberedSet* remembered_set = table_pair.second; 2487 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2488 } 2489 DumpSpaces(LOG(ERROR)); 2490 } 2491 return visitor.GetFailureCount(); 2492} 2493 2494class VerifyReferenceCardVisitor { 2495 public: 2496 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2497 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2498 Locks::heap_bitmap_lock_) 2499 : heap_(heap), failed_(failed) { 2500 } 2501 2502 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2503 // annotalysis on visitors. 2504 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2505 NO_THREAD_SAFETY_ANALYSIS { 2506 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2507 // Filter out class references since changing an object's class does not mark the card as dirty. 2508 // Also handles large objects, since the only reference they hold is a class reference. 2509 if (ref != nullptr && !ref->IsClass()) { 2510 accounting::CardTable* card_table = heap_->GetCardTable(); 2511 // If the object is not dirty and it is referencing something in the live stack other than 2512 // class, then it must be on a dirty card. 2513 if (!card_table->AddrIsInCardTable(obj)) { 2514 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2515 *failed_ = true; 2516 } else if (!card_table->IsDirty(obj)) { 2517 // TODO: Check mod-union tables. 2518 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2519 // kCardDirty - 1 if it didnt get touched since we aged it. 2520 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2521 if (live_stack->ContainsSorted(ref)) { 2522 if (live_stack->ContainsSorted(obj)) { 2523 LOG(ERROR) << "Object " << obj << " found in live stack"; 2524 } 2525 if (heap_->GetLiveBitmap()->Test(obj)) { 2526 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2527 } 2528 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2529 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2530 2531 // Print which field of the object is dead. 2532 if (!obj->IsObjectArray()) { 2533 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2534 CHECK(klass != NULL); 2535 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2536 : klass->GetIFields(); 2537 CHECK(fields != NULL); 2538 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2539 mirror::ArtField* cur = fields->Get(i); 2540 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2541 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2542 << PrettyField(cur); 2543 break; 2544 } 2545 } 2546 } else { 2547 mirror::ObjectArray<mirror::Object>* object_array = 2548 obj->AsObjectArray<mirror::Object>(); 2549 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2550 if (object_array->Get(i) == ref) { 2551 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2552 } 2553 } 2554 } 2555 2556 *failed_ = true; 2557 } 2558 } 2559 } 2560 } 2561 2562 private: 2563 Heap* const heap_; 2564 bool* const failed_; 2565}; 2566 2567class VerifyLiveStackReferences { 2568 public: 2569 explicit VerifyLiveStackReferences(Heap* heap) 2570 : heap_(heap), 2571 failed_(false) {} 2572 2573 void operator()(mirror::Object* obj) const 2574 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2575 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2576 obj->VisitReferences<true>(visitor, VoidFunctor()); 2577 } 2578 2579 bool Failed() const { 2580 return failed_; 2581 } 2582 2583 private: 2584 Heap* const heap_; 2585 bool failed_; 2586}; 2587 2588bool Heap::VerifyMissingCardMarks() { 2589 Thread* self = Thread::Current(); 2590 Locks::mutator_lock_->AssertExclusiveHeld(self); 2591 // We need to sort the live stack since we binary search it. 2592 live_stack_->Sort(); 2593 // Since we sorted the allocation stack content, need to revoke all 2594 // thread-local allocation stacks. 2595 RevokeAllThreadLocalAllocationStacks(self); 2596 VerifyLiveStackReferences visitor(this); 2597 GetLiveBitmap()->Visit(visitor); 2598 // We can verify objects in the live stack since none of these should reference dead objects. 2599 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2600 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2601 visitor(*it); 2602 } 2603 } 2604 return !visitor.Failed(); 2605} 2606 2607void Heap::SwapStacks(Thread* self) { 2608 if (kUseThreadLocalAllocationStack) { 2609 live_stack_->AssertAllZero(); 2610 } 2611 allocation_stack_.swap(live_stack_); 2612} 2613 2614void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2615 // This must be called only during the pause. 2616 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2617 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2618 MutexLock mu2(self, *Locks::thread_list_lock_); 2619 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2620 for (Thread* t : thread_list) { 2621 t->RevokeThreadLocalAllocationStack(); 2622 } 2623} 2624 2625void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2626 if (kIsDebugBuild) { 2627 if (bump_pointer_space_ != nullptr) { 2628 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2629 } 2630 } 2631} 2632 2633accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2634 auto it = mod_union_tables_.find(space); 2635 if (it == mod_union_tables_.end()) { 2636 return nullptr; 2637 } 2638 return it->second; 2639} 2640 2641accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2642 auto it = remembered_sets_.find(space); 2643 if (it == remembered_sets_.end()) { 2644 return nullptr; 2645 } 2646 return it->second; 2647} 2648 2649void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2650 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2651 // Clear cards and keep track of cards cleared in the mod-union table. 2652 for (const auto& space : continuous_spaces_) { 2653 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2654 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2655 if (table != nullptr) { 2656 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2657 "ImageModUnionClearCards"; 2658 TimingLogger::ScopedTiming t(name, timings); 2659 table->ClearCards(); 2660 } else if (use_rem_sets && rem_set != nullptr) { 2661 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2662 << static_cast<int>(collector_type_); 2663 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2664 rem_set->ClearCards(); 2665 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2666 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2667 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2668 // were dirty before the GC started. 2669 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2670 // -> clean(cleaning thread). 2671 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2672 // roots and then we scan / update mod union tables after. We will always scan either card. 2673 // If we end up with the non aged card, we scan it it in the pause. 2674 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2675 VoidFunctor()); 2676 } 2677 } 2678} 2679 2680static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2681} 2682 2683void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2684 Thread* const self = Thread::Current(); 2685 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2686 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2687 if (verify_pre_gc_heap_) { 2688 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2689 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2690 size_t failures = VerifyHeapReferences(); 2691 if (failures > 0) { 2692 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2693 << " failures"; 2694 } 2695 } 2696 // Check that all objects which reference things in the live stack are on dirty cards. 2697 if (verify_missing_card_marks_) { 2698 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2699 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2700 SwapStacks(self); 2701 // Sort the live stack so that we can quickly binary search it later. 2702 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2703 << " missing card mark verification failed\n" << DumpSpaces(); 2704 SwapStacks(self); 2705 } 2706 if (verify_mod_union_table_) { 2707 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2708 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2709 for (const auto& table_pair : mod_union_tables_) { 2710 accounting::ModUnionTable* mod_union_table = table_pair.second; 2711 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2712 mod_union_table->Verify(); 2713 } 2714 } 2715} 2716 2717void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2718 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2719 collector::GarbageCollector::ScopedPause pause(gc); 2720 PreGcVerificationPaused(gc); 2721 } 2722} 2723 2724void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2725 // TODO: Add a new runtime option for this? 2726 if (verify_pre_gc_rosalloc_) { 2727 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2728 } 2729} 2730 2731void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2732 Thread* const self = Thread::Current(); 2733 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2734 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2735 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2736 // reachable objects. 2737 if (verify_pre_sweeping_heap_) { 2738 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2739 CHECK_NE(self->GetState(), kRunnable); 2740 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2741 // Swapping bound bitmaps does nothing. 2742 gc->SwapBitmaps(); 2743 // Pass in false since concurrent reference processing can mean that the reference referents 2744 // may point to dead objects at the point which PreSweepingGcVerification is called. 2745 size_t failures = VerifyHeapReferences(false); 2746 if (failures > 0) { 2747 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2748 << " failures"; 2749 } 2750 gc->SwapBitmaps(); 2751 } 2752 if (verify_pre_sweeping_rosalloc_) { 2753 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2754 } 2755} 2756 2757void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2758 // Only pause if we have to do some verification. 2759 Thread* const self = Thread::Current(); 2760 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2761 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2762 if (verify_system_weaks_) { 2763 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2764 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2765 mark_sweep->VerifySystemWeaks(); 2766 } 2767 if (verify_post_gc_rosalloc_) { 2768 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2769 } 2770 if (verify_post_gc_heap_) { 2771 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2772 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2773 size_t failures = VerifyHeapReferences(); 2774 if (failures > 0) { 2775 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2776 << " failures"; 2777 } 2778 } 2779} 2780 2781void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2782 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2783 collector::GarbageCollector::ScopedPause pause(gc); 2784 PostGcVerificationPaused(gc); 2785 } 2786} 2787 2788void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2789 TimingLogger::ScopedTiming t(name, timings); 2790 for (const auto& space : continuous_spaces_) { 2791 if (space->IsRosAllocSpace()) { 2792 VLOG(heap) << name << " : " << space->GetName(); 2793 space->AsRosAllocSpace()->Verify(); 2794 } 2795 } 2796} 2797 2798collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2799 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2800 MutexLock mu(self, *gc_complete_lock_); 2801 return WaitForGcToCompleteLocked(cause, self); 2802} 2803 2804collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2805 collector::GcType last_gc_type = collector::kGcTypeNone; 2806 uint64_t wait_start = NanoTime(); 2807 while (collector_type_running_ != kCollectorTypeNone) { 2808 ATRACE_BEGIN("GC: Wait For Completion"); 2809 // We must wait, change thread state then sleep on gc_complete_cond_; 2810 gc_complete_cond_->Wait(self); 2811 last_gc_type = last_gc_type_; 2812 ATRACE_END(); 2813 } 2814 uint64_t wait_time = NanoTime() - wait_start; 2815 total_wait_time_ += wait_time; 2816 if (wait_time > long_pause_log_threshold_) { 2817 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2818 << " for cause " << cause; 2819 } 2820 return last_gc_type; 2821} 2822 2823void Heap::DumpForSigQuit(std::ostream& os) { 2824 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2825 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2826 DumpGcPerformanceInfo(os); 2827} 2828 2829size_t Heap::GetPercentFree() { 2830 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2831} 2832 2833void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2834 if (max_allowed_footprint > GetMaxMemory()) { 2835 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2836 << PrettySize(GetMaxMemory()); 2837 max_allowed_footprint = GetMaxMemory(); 2838 } 2839 max_allowed_footprint_ = max_allowed_footprint; 2840} 2841 2842bool Heap::IsMovableObject(const mirror::Object* obj) const { 2843 if (kMovingCollector) { 2844 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2845 if (space != nullptr) { 2846 // TODO: Check large object? 2847 return space->CanMoveObjects(); 2848 } 2849 } 2850 return false; 2851} 2852 2853void Heap::UpdateMaxNativeFootprint() { 2854 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2855 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2856 size_t target_size = native_size / GetTargetHeapUtilization(); 2857 if (target_size > native_size + max_free_) { 2858 target_size = native_size + max_free_; 2859 } else if (target_size < native_size + min_free_) { 2860 target_size = native_size + min_free_; 2861 } 2862 native_footprint_gc_watermark_ = std::min(growth_limit_, target_size); 2863} 2864 2865collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2866 for (const auto& collector : garbage_collectors_) { 2867 if (collector->GetCollectorType() == collector_type_ && 2868 collector->GetGcType() == gc_type) { 2869 return collector; 2870 } 2871 } 2872 return nullptr; 2873} 2874 2875double Heap::HeapGrowthMultiplier() const { 2876 // If we don't care about pause times we are background, so return 1.0. 2877 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2878 return 1.0; 2879 } 2880 return foreground_heap_growth_multiplier_; 2881} 2882 2883void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2884 // We know what our utilization is at this moment. 2885 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2886 const uint64_t bytes_allocated = GetBytesAllocated(); 2887 last_gc_size_ = bytes_allocated; 2888 last_gc_time_ns_ = NanoTime(); 2889 uint64_t target_size; 2890 collector::GcType gc_type = collector_ran->GetGcType(); 2891 if (gc_type != collector::kGcTypeSticky) { 2892 // Grow the heap for non sticky GC. 2893 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2894 // foreground. 2895 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2896 CHECK_GE(delta, 0); 2897 target_size = bytes_allocated + delta * multiplier; 2898 target_size = std::min(target_size, 2899 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2900 target_size = std::max(target_size, 2901 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2902 native_need_to_run_finalization_ = true; 2903 next_gc_type_ = collector::kGcTypeSticky; 2904 } else { 2905 collector::GcType non_sticky_gc_type = 2906 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2907 // Find what the next non sticky collector will be. 2908 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2909 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2910 // do another sticky collection next. 2911 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2912 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2913 // if the sticky GC throughput always remained >= the full/partial throughput. 2914 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2915 non_sticky_collector->GetEstimatedMeanThroughput() && 2916 non_sticky_collector->NumberOfIterations() > 0 && 2917 bytes_allocated <= max_allowed_footprint_) { 2918 next_gc_type_ = collector::kGcTypeSticky; 2919 } else { 2920 next_gc_type_ = non_sticky_gc_type; 2921 } 2922 // If we have freed enough memory, shrink the heap back down. 2923 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2924 target_size = bytes_allocated + max_free_; 2925 } else { 2926 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2927 } 2928 } 2929 if (!ignore_max_footprint_) { 2930 SetIdealFootprint(target_size); 2931 if (IsGcConcurrent()) { 2932 // Calculate when to perform the next ConcurrentGC. 2933 // Calculate the estimated GC duration. 2934 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2935 // Estimate how many remaining bytes we will have when we need to start the next GC. 2936 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2937 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2938 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2939 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2940 // A never going to happen situation that from the estimated allocation rate we will exceed 2941 // the applications entire footprint with the given estimated allocation rate. Schedule 2942 // another GC nearly straight away. 2943 remaining_bytes = kMinConcurrentRemainingBytes; 2944 } 2945 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2946 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2947 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2948 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2949 // right away. 2950 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2951 static_cast<size_t>(bytes_allocated)); 2952 } 2953 } 2954} 2955 2956void Heap::ClearGrowthLimit() { 2957 growth_limit_ = capacity_; 2958 non_moving_space_->ClearGrowthLimit(); 2959} 2960 2961void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2962 ScopedObjectAccess soa(self); 2963 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2964 jvalue args[1]; 2965 args[0].l = arg.get(); 2966 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2967 // Restore object in case it gets moved. 2968 *object = soa.Decode<mirror::Object*>(arg.get()); 2969} 2970 2971void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2972 StackHandleScope<1> hs(self); 2973 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2974 RequestConcurrentGC(self); 2975} 2976 2977void Heap::RequestConcurrentGC(Thread* self) { 2978 // Make sure that we can do a concurrent GC. 2979 Runtime* runtime = Runtime::Current(); 2980 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2981 self->IsHandlingStackOverflow()) { 2982 return; 2983 } 2984 JNIEnv* env = self->GetJniEnv(); 2985 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2986 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2987 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2988 WellKnownClasses::java_lang_Daemons_requestGC); 2989 CHECK(!env->ExceptionCheck()); 2990} 2991 2992void Heap::ConcurrentGC(Thread* self) { 2993 if (Runtime::Current()->IsShuttingDown(self)) { 2994 return; 2995 } 2996 // Wait for any GCs currently running to finish. 2997 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2998 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2999 // instead. E.g. can't do partial, so do full instead. 3000 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 3001 collector::kGcTypeNone) { 3002 for (collector::GcType gc_type : gc_plan_) { 3003 // Attempt to run the collector, if we succeed, we are done. 3004 if (gc_type > next_gc_type_ && 3005 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 3006 break; 3007 } 3008 } 3009 } 3010 } 3011} 3012 3013void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 3014 Thread* self = Thread::Current(); 3015 { 3016 MutexLock mu(self, *heap_trim_request_lock_); 3017 if (desired_collector_type_ == desired_collector_type) { 3018 return; 3019 } 3020 heap_transition_or_trim_target_time_ = 3021 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 3022 desired_collector_type_ = desired_collector_type; 3023 } 3024 SignalHeapTrimDaemon(self); 3025} 3026 3027void Heap::RequestHeapTrim() { 3028 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 3029 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 3030 // a space it will hold its lock and can become a cause of jank. 3031 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 3032 // forking. 3033 3034 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 3035 // because that only marks object heads, so a large array looks like lots of empty space. We 3036 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 3037 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3038 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3039 // not how much use we're making of those pages. 3040 3041 Thread* self = Thread::Current(); 3042 Runtime* runtime = Runtime::Current(); 3043 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 3044 runtime->IsZygote()) { 3045 // Ignore the request if we are the zygote to prevent app launching lag due to sleep in heap 3046 // trimmer daemon. b/17310019 3047 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3048 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3049 // as we don't hold the lock while requesting the trim). 3050 return; 3051 } 3052 { 3053 MutexLock mu(self, *heap_trim_request_lock_); 3054 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3055 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3056 // just yet. 3057 return; 3058 } 3059 heap_trim_request_pending_ = true; 3060 uint64_t current_time = NanoTime(); 3061 if (heap_transition_or_trim_target_time_ < current_time) { 3062 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 3063 } 3064 } 3065 // Notify the daemon thread which will actually do the heap trim. 3066 SignalHeapTrimDaemon(self); 3067} 3068 3069void Heap::SignalHeapTrimDaemon(Thread* self) { 3070 JNIEnv* env = self->GetJniEnv(); 3071 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3072 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3073 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3074 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3075 CHECK(!env->ExceptionCheck()); 3076} 3077 3078void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3079 if (rosalloc_space_ != nullptr) { 3080 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3081 } 3082 if (bump_pointer_space_ != nullptr) { 3083 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3084 } 3085} 3086 3087void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3088 if (rosalloc_space_ != nullptr) { 3089 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3090 } 3091} 3092 3093void Heap::RevokeAllThreadLocalBuffers() { 3094 if (rosalloc_space_ != nullptr) { 3095 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3096 } 3097 if (bump_pointer_space_ != nullptr) { 3098 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3099 } 3100} 3101 3102bool Heap::IsGCRequestPending() const { 3103 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3104} 3105 3106void Heap::RunFinalization(JNIEnv* env) { 3107 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3108 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3109 CHECK(WellKnownClasses::java_lang_System != nullptr); 3110 WellKnownClasses::java_lang_System_runFinalization = 3111 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3112 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3113 } 3114 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3115 WellKnownClasses::java_lang_System_runFinalization); 3116 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3117 WellKnownClasses::java_lang_System_runFinalization); 3118} 3119 3120void Heap::RegisterNativeAllocation(JNIEnv* env, size_t bytes) { 3121 Thread* self = ThreadForEnv(env); 3122 if (native_need_to_run_finalization_) { 3123 RunFinalization(env); 3124 UpdateMaxNativeFootprint(); 3125 native_need_to_run_finalization_ = false; 3126 } 3127 // Total number of native bytes allocated. 3128 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3129 new_native_bytes_allocated += bytes; 3130 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3131 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 3132 collector::kGcTypeFull; 3133 3134 // The second watermark is higher than the gc watermark. If you hit this it means you are 3135 // allocating native objects faster than the GC can keep up with. 3136 if (new_native_bytes_allocated > growth_limit_) { 3137 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3138 // Just finished a GC, attempt to run finalizers. 3139 RunFinalization(env); 3140 CHECK(!env->ExceptionCheck()); 3141 } 3142 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3143 if (new_native_bytes_allocated > growth_limit_) { 3144 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3145 RunFinalization(env); 3146 native_need_to_run_finalization_ = false; 3147 CHECK(!env->ExceptionCheck()); 3148 } 3149 // We have just run finalizers, update the native watermark since it is very likely that 3150 // finalizers released native managed allocations. 3151 UpdateMaxNativeFootprint(); 3152 } else if (!IsGCRequestPending()) { 3153 if (IsGcConcurrent()) { 3154 RequestConcurrentGC(self); 3155 } else { 3156 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3157 } 3158 } 3159 } 3160} 3161 3162void Heap::RegisterNativeFree(JNIEnv* env, size_t bytes) { 3163 size_t expected_size; 3164 do { 3165 expected_size = native_bytes_allocated_.LoadRelaxed(); 3166 if (UNLIKELY(bytes > expected_size)) { 3167 ScopedObjectAccess soa(env); 3168 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3169 StringPrintf("Attempted to free %zd native bytes with only %zd native bytes " 3170 "registered as allocated", bytes, expected_size).c_str()); 3171 break; 3172 } 3173 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, 3174 expected_size - bytes)); 3175} 3176 3177size_t Heap::GetTotalMemory() const { 3178 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3179} 3180 3181void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3182 DCHECK(mod_union_table != nullptr); 3183 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3184} 3185 3186void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3187 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3188 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3189 CHECK_GE(byte_count, sizeof(mirror::Object)); 3190} 3191 3192void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3193 CHECK(remembered_set != nullptr); 3194 space::Space* space = remembered_set->GetSpace(); 3195 CHECK(space != nullptr); 3196 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3197 remembered_sets_.Put(space, remembered_set); 3198 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3199} 3200 3201void Heap::RemoveRememberedSet(space::Space* space) { 3202 CHECK(space != nullptr); 3203 auto it = remembered_sets_.find(space); 3204 CHECK(it != remembered_sets_.end()); 3205 delete it->second; 3206 remembered_sets_.erase(it); 3207 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3208} 3209 3210void Heap::ClearMarkedObjects() { 3211 // Clear all of the spaces' mark bitmaps. 3212 for (const auto& space : GetContinuousSpaces()) { 3213 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3214 if (space->GetLiveBitmap() != mark_bitmap) { 3215 mark_bitmap->Clear(); 3216 } 3217 } 3218 // Clear the marked objects in the discontinous space object sets. 3219 for (const auto& space : GetDiscontinuousSpaces()) { 3220 space->GetMarkBitmap()->Clear(); 3221 } 3222} 3223 3224} // namespace gc 3225} // namespace art 3226