heap.cc revision de2233bbf64c7dde96513a729f6a97aebc2f0424
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <memory> 24#include <vector> 25 26#include "base/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/remembered_set.h" 37#include "gc/accounting/space_bitmap-inl.h" 38#include "gc/collector/concurrent_copying.h" 39#include "gc/collector/mark_compact.h" 40#include "gc/collector/mark_sweep-inl.h" 41#include "gc/collector/partial_mark_sweep.h" 42#include "gc/collector/semi_space.h" 43#include "gc/collector/sticky_mark_sweep.h" 44#include "gc/reference_processor.h" 45#include "gc/space/bump_pointer_space.h" 46#include "gc/space/dlmalloc_space-inl.h" 47#include "gc/space/image_space.h" 48#include "gc/space/large_object_space.h" 49#include "gc/space/rosalloc_space-inl.h" 50#include "gc/space/space-inl.h" 51#include "gc/space/zygote_space.h" 52#include "entrypoints/quick/quick_alloc_entrypoints.h" 53#include "heap-inl.h" 54#include "image.h" 55#include "mirror/art_field-inl.h" 56#include "mirror/class-inl.h" 57#include "mirror/object.h" 58#include "mirror/object-inl.h" 59#include "mirror/object_array-inl.h" 60#include "mirror/reference-inl.h" 61#include "os.h" 62#include "reflection.h" 63#include "runtime.h" 64#include "ScopedLocalRef.h" 65#include "scoped_thread_state_change.h" 66#include "handle_scope-inl.h" 67#include "thread_list.h" 68#include "well_known_classes.h" 69 70namespace art { 71 72namespace gc { 73 74static constexpr size_t kCollectorTransitionStressIterations = 0; 75static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 76static constexpr bool kGCALotMode = false; 77static constexpr size_t kGcAlotInterval = KB; 78// Minimum amount of remaining bytes before a concurrent GC is triggered. 79static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 80static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 81// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 82// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 83// threads (lower pauses, use less memory bandwidth). 84static constexpr double kStickyGcThroughputAdjustment = 1.0; 85// Whether or not we use the free list large object space. 86static constexpr bool kUseFreeListSpaceForLOS = false; 87// Whether or not we compact the zygote in PreZygoteFork. 88static constexpr bool kCompactZygote = kMovingCollector; 89// How many reserve entries are at the end of the allocation stack, these are only needed if the 90// allocation stack overflows. 91static constexpr size_t kAllocationStackReserveSize = 1024; 92// Default mark stack size in bytes. 93static const size_t kDefaultMarkStackSize = 64 * KB; 94// Define space name. 95static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 96static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 97static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 98static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 99 100Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 101 double target_utilization, double foreground_heap_growth_multiplier, 102 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 103 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 104 CollectorType background_collector_type, size_t parallel_gc_threads, 105 size_t conc_gc_threads, bool low_memory_mode, 106 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 107 bool ignore_max_footprint, bool use_tlab, 108 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 109 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 110 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 111 uint64_t min_interval_homogeneous_space_compaction_by_oom) 112 : non_moving_space_(nullptr), 113 rosalloc_space_(nullptr), 114 dlmalloc_space_(nullptr), 115 main_space_(nullptr), 116 collector_type_(kCollectorTypeNone), 117 foreground_collector_type_(foreground_collector_type), 118 background_collector_type_(background_collector_type), 119 desired_collector_type_(foreground_collector_type_), 120 heap_trim_request_lock_(nullptr), 121 last_trim_time_(0), 122 heap_transition_or_trim_target_time_(0), 123 heap_trim_request_pending_(false), 124 parallel_gc_threads_(parallel_gc_threads), 125 conc_gc_threads_(conc_gc_threads), 126 low_memory_mode_(low_memory_mode), 127 long_pause_log_threshold_(long_pause_log_threshold), 128 long_gc_log_threshold_(long_gc_log_threshold), 129 ignore_max_footprint_(ignore_max_footprint), 130 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 131 have_zygote_space_(false), 132 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 133 collector_type_running_(kCollectorTypeNone), 134 last_gc_type_(collector::kGcTypeNone), 135 next_gc_type_(collector::kGcTypePartial), 136 capacity_(capacity), 137 growth_limit_(growth_limit), 138 max_allowed_footprint_(initial_size), 139 native_footprint_gc_watermark_(initial_size), 140 native_footprint_limit_(2 * initial_size), 141 native_need_to_run_finalization_(false), 142 // Initially assume we perceive jank in case the process state is never updated. 143 process_state_(kProcessStateJankPerceptible), 144 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 145 total_bytes_freed_ever_(0), 146 total_objects_freed_ever_(0), 147 num_bytes_allocated_(0), 148 native_bytes_allocated_(0), 149 gc_memory_overhead_(0), 150 verify_missing_card_marks_(false), 151 verify_system_weaks_(false), 152 verify_pre_gc_heap_(verify_pre_gc_heap), 153 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 154 verify_post_gc_heap_(verify_post_gc_heap), 155 verify_mod_union_table_(false), 156 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 157 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 158 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 159 last_gc_time_ns_(NanoTime()), 160 allocation_rate_(0), 161 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 162 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 163 * verification is enabled, we limit the size of allocation stacks to speed up their 164 * searching. 165 */ 166 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 167 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 168 current_allocator_(kAllocatorTypeDlMalloc), 169 current_non_moving_allocator_(kAllocatorTypeNonMoving), 170 bump_pointer_space_(nullptr), 171 temp_space_(nullptr), 172 min_free_(min_free), 173 max_free_(max_free), 174 target_utilization_(target_utilization), 175 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 176 total_wait_time_(0), 177 total_allocation_time_(0), 178 verify_object_mode_(kVerifyObjectModeDisabled), 179 disable_moving_gc_count_(0), 180 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 181 use_tlab_(use_tlab), 182 main_space_backup_(nullptr), 183 min_interval_homogeneous_space_compaction_by_oom_( 184 min_interval_homogeneous_space_compaction_by_oom), 185 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 186 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 187 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 188 LOG(INFO) << "Heap() entering"; 189 } 190 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 191 // entrypoints. 192 if (!Runtime::Current()->IsZygote()) { 193 large_object_threshold_ = kDefaultLargeObjectThreshold; 194 // Background compaction is currently not supported for command line runs. 195 if (background_collector_type_ != foreground_collector_type_) { 196 VLOG(heap) << "Disabling background compaction for non zygote"; 197 background_collector_type_ = foreground_collector_type_; 198 } 199 } 200 ChangeCollector(desired_collector_type_); 201 live_bitmap_.reset(new accounting::HeapBitmap(this)); 202 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 203 // Requested begin for the alloc space, to follow the mapped image and oat files 204 byte* requested_alloc_space_begin = nullptr; 205 if (!image_file_name.empty()) { 206 std::string error_msg; 207 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 208 image_instruction_set, 209 &error_msg); 210 if (image_space != nullptr) { 211 AddSpace(image_space); 212 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 213 // isn't going to get in the middle 214 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 215 CHECK_GT(oat_file_end_addr, image_space->End()); 216 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 217 } else { 218 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 219 << "Attempting to fall back to imageless running. Error was: " << error_msg; 220 } 221 } 222 /* 223 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 224 +- nonmoving space (non_moving_space_capacity)+- 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 226 +-main alloc space / bump space 1 (capacity_) +- 227 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 228 +-????????????????????????????????????????????+- 229 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 230 +-main alloc space2 / bump space 2 (capacity_)+- 231 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 232 */ 233 bool support_homogeneous_space_compaction = 234 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 235 use_homogeneous_space_compaction_for_oom; 236 // We may use the same space the main space for the non moving space if we don't need to compact 237 // from the main space. 238 // This is not the case if we support homogeneous compaction or have a moving background 239 // collector type. 240 const bool is_zygote = Runtime::Current()->IsZygote(); 241 bool separate_non_moving_space = is_zygote || 242 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 243 IsMovingGc(background_collector_type_); 244 if (foreground_collector_type == kCollectorTypeGSS) { 245 separate_non_moving_space = false; 246 } 247 std::unique_ptr<MemMap> main_mem_map_1; 248 std::unique_ptr<MemMap> main_mem_map_2; 249 byte* request_begin = requested_alloc_space_begin; 250 if (request_begin != nullptr && separate_non_moving_space) { 251 request_begin += non_moving_space_capacity; 252 } 253 std::string error_str; 254 std::unique_ptr<MemMap> non_moving_space_mem_map; 255 if (separate_non_moving_space) { 256 // Reserve the non moving mem map before the other two since it needs to be at a specific 257 // address. 258 non_moving_space_mem_map.reset( 259 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 260 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 261 CHECK(non_moving_space_mem_map != nullptr) << error_str; 262 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 263 request_begin = reinterpret_cast<byte*>(0x1000000); 264 } 265 // Attempt to create 2 mem maps at or after the requested begin. 266 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 267 PROT_READ | PROT_WRITE, &error_str)); 268 CHECK(main_mem_map_1.get() != nullptr) << error_str; 269 if (support_homogeneous_space_compaction || 270 background_collector_type_ == kCollectorTypeSS || 271 foreground_collector_type_ == kCollectorTypeSS) { 272 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 273 capacity_, PROT_READ | PROT_WRITE, 274 &error_str)); 275 CHECK(main_mem_map_2.get() != nullptr) << error_str; 276 } 277 // Create the non moving space first so that bitmaps don't take up the address range. 278 if (separate_non_moving_space) { 279 // Non moving space is always dlmalloc since we currently don't have support for multiple 280 // active rosalloc spaces. 281 const size_t size = non_moving_space_mem_map->Size(); 282 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 283 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 284 initial_size, size, size, false); 285 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 286 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 287 << requested_alloc_space_begin; 288 AddSpace(non_moving_space_); 289 } 290 // Create other spaces based on whether or not we have a moving GC. 291 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 292 // Create bump pointer spaces. 293 // We only to create the bump pointer if the foreground collector is a compacting GC. 294 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 295 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 296 main_mem_map_1.release()); 297 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 298 AddSpace(bump_pointer_space_); 299 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 300 main_mem_map_2.release()); 301 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 302 AddSpace(temp_space_); 303 CHECK(separate_non_moving_space); 304 } else { 305 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 306 CHECK(main_space_ != nullptr); 307 AddSpace(main_space_); 308 if (!separate_non_moving_space) { 309 non_moving_space_ = main_space_; 310 CHECK(!non_moving_space_->CanMoveObjects()); 311 } 312 if (foreground_collector_type_ == kCollectorTypeGSS) { 313 CHECK_EQ(foreground_collector_type_, background_collector_type_); 314 // Create bump pointer spaces instead of a backup space. 315 main_mem_map_2.release(); 316 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 317 kGSSBumpPointerSpaceCapacity, nullptr); 318 CHECK(bump_pointer_space_ != nullptr); 319 AddSpace(bump_pointer_space_); 320 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 321 kGSSBumpPointerSpaceCapacity, nullptr); 322 CHECK(temp_space_ != nullptr); 323 AddSpace(temp_space_); 324 } else if (main_mem_map_2.get() != nullptr) { 325 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 326 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 327 growth_limit_, capacity_, name, true)); 328 CHECK(main_space_backup_.get() != nullptr); 329 // Add the space so its accounted for in the heap_begin and heap_end. 330 AddSpace(main_space_backup_.get()); 331 } 332 } 333 CHECK(non_moving_space_ != nullptr); 334 CHECK(!non_moving_space_->CanMoveObjects()); 335 // Allocate the large object space. 336 if (kUseFreeListSpaceForLOS) { 337 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 338 } else { 339 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 340 } 341 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 342 AddSpace(large_object_space_); 343 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 344 CHECK(!continuous_spaces_.empty()); 345 // Relies on the spaces being sorted. 346 byte* heap_begin = continuous_spaces_.front()->Begin(); 347 byte* heap_end = continuous_spaces_.back()->Limit(); 348 size_t heap_capacity = heap_end - heap_begin; 349 // Remove the main backup space since it slows down the GC to have unused extra spaces. 350 if (main_space_backup_.get() != nullptr) { 351 RemoveSpace(main_space_backup_.get()); 352 } 353 // Allocate the card table. 354 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 355 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 356 // Card cache for now since it makes it easier for us to update the references to the copying 357 // spaces. 358 accounting::ModUnionTable* mod_union_table = 359 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 360 GetImageSpace()); 361 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 362 AddModUnionTable(mod_union_table); 363 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 364 accounting::RememberedSet* non_moving_space_rem_set = 365 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 366 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 367 AddRememberedSet(non_moving_space_rem_set); 368 } 369 // TODO: Count objects in the image space here? 370 num_bytes_allocated_.StoreRelaxed(0); 371 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 372 kDefaultMarkStackSize)); 373 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 374 allocation_stack_.reset(accounting::ObjectStack::Create( 375 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 376 live_stack_.reset(accounting::ObjectStack::Create( 377 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 378 // It's still too early to take a lock because there are no threads yet, but we can create locks 379 // now. We don't create it earlier to make it clear that you can't use locks during heap 380 // initialization. 381 gc_complete_lock_ = new Mutex("GC complete lock"); 382 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 383 *gc_complete_lock_)); 384 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 385 last_gc_size_ = GetBytesAllocated(); 386 if (ignore_max_footprint_) { 387 SetIdealFootprint(std::numeric_limits<size_t>::max()); 388 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 389 } 390 CHECK_NE(max_allowed_footprint_, 0U); 391 // Create our garbage collectors. 392 for (size_t i = 0; i < 2; ++i) { 393 const bool concurrent = i != 0; 394 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 395 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 396 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 397 } 398 if (kMovingCollector) { 399 // TODO: Clean this up. 400 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 401 semi_space_collector_ = new collector::SemiSpace(this, generational, 402 generational ? "generational" : ""); 403 garbage_collectors_.push_back(semi_space_collector_); 404 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 405 garbage_collectors_.push_back(concurrent_copying_collector_); 406 mark_compact_collector_ = new collector::MarkCompact(this); 407 garbage_collectors_.push_back(mark_compact_collector_); 408 } 409 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr) { 410 // Check that there's no gap between the image space and the non moving space so that the 411 // immune region won't break (eg. due to a large object allocated in the gap). 412 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 413 non_moving_space_->GetMemMap()); 414 if (!no_gap) { 415 MemMap::DumpMaps(LOG(ERROR)); 416 LOG(FATAL) << "There's a gap between the image space and the main space"; 417 } 418 } 419 if (running_on_valgrind_) { 420 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 421 } 422 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 423 LOG(INFO) << "Heap() exiting"; 424 } 425} 426 427MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 428 int prot_flags, std::string* out_error_str) { 429 while (true) { 430 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 431 PROT_READ | PROT_WRITE, true, out_error_str); 432 if (map != nullptr || request_begin == nullptr) { 433 return map; 434 } 435 // Retry a second time with no specified request begin. 436 request_begin = nullptr; 437 } 438 return nullptr; 439} 440 441space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 442 size_t growth_limit, size_t capacity, 443 const char* name, bool can_move_objects) { 444 space::MallocSpace* malloc_space = nullptr; 445 if (kUseRosAlloc) { 446 // Create rosalloc space. 447 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 448 initial_size, growth_limit, capacity, 449 low_memory_mode_, can_move_objects); 450 } else { 451 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 452 initial_size, growth_limit, capacity, 453 can_move_objects); 454 } 455 if (collector::SemiSpace::kUseRememberedSet) { 456 accounting::RememberedSet* rem_set = 457 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 458 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 459 AddRememberedSet(rem_set); 460 } 461 CHECK(malloc_space != nullptr) << "Failed to create " << name; 462 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 463 return malloc_space; 464} 465 466void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 467 size_t capacity) { 468 // Is background compaction is enabled? 469 bool can_move_objects = IsMovingGc(background_collector_type_) != 470 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 471 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 472 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 473 // from the main space to the zygote space. If background compaction is enabled, always pass in 474 // that we can move objets. 475 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 476 // After the zygote we want this to be false if we don't have background compaction enabled so 477 // that getting primitive array elements is faster. 478 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 479 can_move_objects = !have_zygote_space_ && foreground_collector_type_ != kCollectorTypeGSS; 480 } 481 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 482 RemoveRememberedSet(main_space_); 483 } 484 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 485 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 486 can_move_objects); 487 SetSpaceAsDefault(main_space_); 488 VLOG(heap) << "Created main space " << main_space_; 489} 490 491void Heap::ChangeAllocator(AllocatorType allocator) { 492 if (current_allocator_ != allocator) { 493 // These two allocators are only used internally and don't have any entrypoints. 494 CHECK_NE(allocator, kAllocatorTypeLOS); 495 CHECK_NE(allocator, kAllocatorTypeNonMoving); 496 current_allocator_ = allocator; 497 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 498 SetQuickAllocEntryPointsAllocator(current_allocator_); 499 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 500 } 501} 502 503void Heap::DisableMovingGc() { 504 if (IsMovingGc(foreground_collector_type_)) { 505 foreground_collector_type_ = kCollectorTypeCMS; 506 } 507 if (IsMovingGc(background_collector_type_)) { 508 background_collector_type_ = foreground_collector_type_; 509 } 510 TransitionCollector(foreground_collector_type_); 511 ThreadList* tl = Runtime::Current()->GetThreadList(); 512 Thread* self = Thread::Current(); 513 ScopedThreadStateChange tsc(self, kSuspended); 514 tl->SuspendAll(); 515 // Something may have caused the transition to fail. 516 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 517 CHECK(main_space_ != nullptr); 518 // The allocation stack may have non movable objects in it. We need to flush it since the GC 519 // can't only handle marking allocation stack objects of one non moving space and one main 520 // space. 521 { 522 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 523 FlushAllocStack(); 524 } 525 main_space_->DisableMovingObjects(); 526 non_moving_space_ = main_space_; 527 CHECK(!non_moving_space_->CanMoveObjects()); 528 } 529 tl->ResumeAll(); 530} 531 532std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 533 if (!IsValidContinuousSpaceObjectAddress(klass)) { 534 return StringPrintf("<non heap address klass %p>", klass); 535 } 536 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 537 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 538 std::string result("["); 539 result += SafeGetClassDescriptor(component_type); 540 return result; 541 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 542 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 543 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 544 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 545 } else { 546 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 547 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 548 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 549 } 550 const DexFile* dex_file = dex_cache->GetDexFile(); 551 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 552 if (class_def_idx == DexFile::kDexNoIndex16) { 553 return "<class def not found>"; 554 } 555 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 556 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 557 return dex_file->GetTypeDescriptor(type_id); 558 } 559} 560 561std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 562 if (obj == nullptr) { 563 return "null"; 564 } 565 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 566 if (klass == nullptr) { 567 return "(class=null)"; 568 } 569 std::string result(SafeGetClassDescriptor(klass)); 570 if (obj->IsClass()) { 571 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 572 } 573 return result; 574} 575 576void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 577 if (obj == nullptr) { 578 stream << "(obj=null)"; 579 return; 580 } 581 if (IsAligned<kObjectAlignment>(obj)) { 582 space::Space* space = nullptr; 583 // Don't use find space since it only finds spaces which actually contain objects instead of 584 // spaces which may contain objects (e.g. cleared bump pointer spaces). 585 for (const auto& cur_space : continuous_spaces_) { 586 if (cur_space->HasAddress(obj)) { 587 space = cur_space; 588 break; 589 } 590 } 591 // Unprotect all the spaces. 592 for (const auto& space : continuous_spaces_) { 593 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 594 } 595 stream << "Object " << obj; 596 if (space != nullptr) { 597 stream << " in space " << *space; 598 } 599 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 600 stream << "\nclass=" << klass; 601 if (klass != nullptr) { 602 stream << " type= " << SafePrettyTypeOf(obj); 603 } 604 // Re-protect the address we faulted on. 605 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 606 } 607} 608 609bool Heap::IsCompilingBoot() const { 610 if (!Runtime::Current()->IsCompiler()) { 611 return false; 612 } 613 for (const auto& space : continuous_spaces_) { 614 if (space->IsImageSpace() || space->IsZygoteSpace()) { 615 return false; 616 } 617 } 618 return true; 619} 620 621bool Heap::HasImageSpace() const { 622 for (const auto& space : continuous_spaces_) { 623 if (space->IsImageSpace()) { 624 return true; 625 } 626 } 627 return false; 628} 629 630void Heap::IncrementDisableMovingGC(Thread* self) { 631 // Need to do this holding the lock to prevent races where the GC is about to run / running when 632 // we attempt to disable it. 633 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 634 MutexLock mu(self, *gc_complete_lock_); 635 ++disable_moving_gc_count_; 636 if (IsMovingGc(collector_type_running_)) { 637 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 638 } 639} 640 641void Heap::DecrementDisableMovingGC(Thread* self) { 642 MutexLock mu(self, *gc_complete_lock_); 643 CHECK_GE(disable_moving_gc_count_, 0U); 644 --disable_moving_gc_count_; 645} 646 647void Heap::UpdateProcessState(ProcessState process_state) { 648 if (process_state_ != process_state) { 649 process_state_ = process_state; 650 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 651 // Start at index 1 to avoid "is always false" warning. 652 // Have iteration 1 always transition the collector. 653 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 654 ? foreground_collector_type_ : background_collector_type_); 655 usleep(kCollectorTransitionStressWait); 656 } 657 if (process_state_ == kProcessStateJankPerceptible) { 658 // Transition back to foreground right away to prevent jank. 659 RequestCollectorTransition(foreground_collector_type_, 0); 660 } else { 661 // Don't delay for debug builds since we may want to stress test the GC. 662 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 663 // special handling which does a homogenous space compaction once but then doesn't transition 664 // the collector. 665 RequestCollectorTransition(background_collector_type_, 666 kIsDebugBuild ? 0 : kCollectorTransitionWait); 667 } 668 } 669} 670 671void Heap::CreateThreadPool() { 672 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 673 if (num_threads != 0) { 674 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 675 } 676} 677 678void Heap::VisitObjects(ObjectCallback callback, void* arg) { 679 Thread* self = Thread::Current(); 680 // GCs can move objects, so don't allow this. 681 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 682 if (bump_pointer_space_ != nullptr) { 683 // Visit objects in bump pointer space. 684 bump_pointer_space_->Walk(callback, arg); 685 } 686 // TODO: Switch to standard begin and end to use ranged a based loop. 687 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 688 it < end; ++it) { 689 mirror::Object* obj = *it; 690 if (obj != nullptr && obj->GetClass() != nullptr) { 691 // Avoid the race condition caused by the object not yet being written into the allocation 692 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 693 // there can be nulls on the allocation stack. 694 callback(obj, arg); 695 } 696 } 697 GetLiveBitmap()->Walk(callback, arg); 698 self->EndAssertNoThreadSuspension(old_cause); 699} 700 701void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 702 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 703 space::ContinuousSpace* space2 = non_moving_space_; 704 // TODO: Generalize this to n bitmaps? 705 CHECK(space1 != nullptr); 706 CHECK(space2 != nullptr); 707 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 708 large_object_space_->GetLiveBitmap(), stack); 709} 710 711void Heap::DeleteThreadPool() { 712 thread_pool_.reset(nullptr); 713} 714 715void Heap::AddSpace(space::Space* space) { 716 CHECK(space != nullptr); 717 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 718 if (space->IsContinuousSpace()) { 719 DCHECK(!space->IsDiscontinuousSpace()); 720 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 721 // Continuous spaces don't necessarily have bitmaps. 722 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 723 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 724 if (live_bitmap != nullptr) { 725 CHECK(mark_bitmap != nullptr); 726 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 727 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 728 } 729 continuous_spaces_.push_back(continuous_space); 730 // Ensure that spaces remain sorted in increasing order of start address. 731 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 732 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 733 return a->Begin() < b->Begin(); 734 }); 735 } else { 736 CHECK(space->IsDiscontinuousSpace()); 737 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 738 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 739 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 740 discontinuous_spaces_.push_back(discontinuous_space); 741 } 742 if (space->IsAllocSpace()) { 743 alloc_spaces_.push_back(space->AsAllocSpace()); 744 } 745} 746 747void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 748 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 749 if (continuous_space->IsDlMallocSpace()) { 750 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 751 } else if (continuous_space->IsRosAllocSpace()) { 752 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 753 } 754} 755 756void Heap::RemoveSpace(space::Space* space) { 757 DCHECK(space != nullptr); 758 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 759 if (space->IsContinuousSpace()) { 760 DCHECK(!space->IsDiscontinuousSpace()); 761 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 762 // Continuous spaces don't necessarily have bitmaps. 763 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 764 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 765 if (live_bitmap != nullptr) { 766 DCHECK(mark_bitmap != nullptr); 767 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 768 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 769 } 770 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 771 DCHECK(it != continuous_spaces_.end()); 772 continuous_spaces_.erase(it); 773 } else { 774 DCHECK(space->IsDiscontinuousSpace()); 775 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 776 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 777 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 778 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 779 discontinuous_space); 780 DCHECK(it != discontinuous_spaces_.end()); 781 discontinuous_spaces_.erase(it); 782 } 783 if (space->IsAllocSpace()) { 784 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 785 DCHECK(it != alloc_spaces_.end()); 786 alloc_spaces_.erase(it); 787 } 788} 789 790void Heap::RegisterGCAllocation(size_t bytes) { 791 gc_memory_overhead_.FetchAndAddSequentiallyConsistent(bytes); 792} 793 794void Heap::RegisterGCDeAllocation(size_t bytes) { 795 gc_memory_overhead_.FetchAndSubSequentiallyConsistent(bytes); 796} 797 798void Heap::DumpGcPerformanceInfo(std::ostream& os) { 799 // Dump cumulative timings. 800 os << "Dumping cumulative Gc timings\n"; 801 uint64_t total_duration = 0; 802 // Dump cumulative loggers for each GC type. 803 uint64_t total_paused_time = 0; 804 for (auto& collector : garbage_collectors_) { 805 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 806 const size_t iterations = logger.GetIterations(); 807 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 808 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 809 os << ConstDumpable<CumulativeLogger>(logger); 810 const uint64_t total_ns = logger.GetTotalNs(); 811 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 812 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 813 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 814 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 815 Histogram<uint64_t>::CumulativeData cumulative_data; 816 pause_histogram.CreateHistogram(&cumulative_data); 817 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 818 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 819 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 820 << collector->GetName() << " freed: " << freed_objects 821 << " objects with total size " << PrettySize(freed_bytes) << "\n" 822 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 823 << PrettySize(freed_bytes / seconds) << "/s\n"; 824 total_duration += total_ns; 825 total_paused_time += total_pause_ns; 826 } 827 collector->ResetMeasurements(); 828 } 829 uint64_t allocation_time = 830 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 831 if (total_duration != 0) { 832 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 833 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 834 os << "Mean GC size throughput: " 835 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 836 os << "Mean GC object throughput: " 837 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 838 } 839 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 840 os << "Total number of allocations " << total_objects_allocated << "\n"; 841 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 842 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 843 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 844 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 845 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 846 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 847 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 848 if (kMeasureAllocationTime) { 849 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 850 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 851 << "\n"; 852 } 853 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 854 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 855 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_.LoadRelaxed(); 856 BaseMutex::DumpAll(os); 857} 858 859Heap::~Heap() { 860 VLOG(heap) << "Starting ~Heap()"; 861 STLDeleteElements(&garbage_collectors_); 862 // If we don't reset then the mark stack complains in its destructor. 863 allocation_stack_->Reset(); 864 live_stack_->Reset(); 865 STLDeleteValues(&mod_union_tables_); 866 STLDeleteValues(&remembered_sets_); 867 STLDeleteElements(&continuous_spaces_); 868 STLDeleteElements(&discontinuous_spaces_); 869 delete gc_complete_lock_; 870 delete heap_trim_request_lock_; 871 VLOG(heap) << "Finished ~Heap()"; 872} 873 874space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 875 bool fail_ok) const { 876 for (const auto& space : continuous_spaces_) { 877 if (space->Contains(obj)) { 878 return space; 879 } 880 } 881 if (!fail_ok) { 882 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 883 } 884 return NULL; 885} 886 887space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 888 bool fail_ok) const { 889 for (const auto& space : discontinuous_spaces_) { 890 if (space->Contains(obj)) { 891 return space; 892 } 893 } 894 if (!fail_ok) { 895 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 896 } 897 return NULL; 898} 899 900space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 901 space::Space* result = FindContinuousSpaceFromObject(obj, true); 902 if (result != NULL) { 903 return result; 904 } 905 return FindDiscontinuousSpaceFromObject(obj, true); 906} 907 908space::ImageSpace* Heap::GetImageSpace() const { 909 for (const auto& space : continuous_spaces_) { 910 if (space->IsImageSpace()) { 911 return space->AsImageSpace(); 912 } 913 } 914 return NULL; 915} 916 917void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 918 std::ostringstream oss; 919 size_t total_bytes_free = GetFreeMemory(); 920 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 921 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 922 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 923 if (total_bytes_free >= byte_count) { 924 space::AllocSpace* space = nullptr; 925 if (allocator_type == kAllocatorTypeNonMoving) { 926 space = non_moving_space_; 927 } else if (allocator_type == kAllocatorTypeRosAlloc || 928 allocator_type == kAllocatorTypeDlMalloc) { 929 space = main_space_; 930 } else if (allocator_type == kAllocatorTypeBumpPointer || 931 allocator_type == kAllocatorTypeTLAB) { 932 space = bump_pointer_space_; 933 } 934 if (space != nullptr) { 935 space->LogFragmentationAllocFailure(oss, byte_count); 936 } 937 } 938 self->ThrowOutOfMemoryError(oss.str().c_str()); 939} 940 941void Heap::DoPendingTransitionOrTrim() { 942 Thread* self = Thread::Current(); 943 CollectorType desired_collector_type; 944 // Wait until we reach the desired transition time. 945 while (true) { 946 uint64_t wait_time; 947 { 948 MutexLock mu(self, *heap_trim_request_lock_); 949 desired_collector_type = desired_collector_type_; 950 uint64_t current_time = NanoTime(); 951 if (current_time >= heap_transition_or_trim_target_time_) { 952 break; 953 } 954 wait_time = heap_transition_or_trim_target_time_ - current_time; 955 } 956 ScopedThreadStateChange tsc(self, kSleeping); 957 usleep(wait_time / 1000); // Usleep takes microseconds. 958 } 959 // Launch homogeneous space compaction if it is desired. 960 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 961 if (!CareAboutPauseTimes()) { 962 PerformHomogeneousSpaceCompact(); 963 } 964 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 965 desired_collector_type = collector_type_; 966 return; 967 } 968 // Transition the collector if the desired collector type is not the same as the current 969 // collector type. 970 TransitionCollector(desired_collector_type); 971 if (!CareAboutPauseTimes()) { 972 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 973 // about pauses. 974 Runtime* runtime = Runtime::Current(); 975 runtime->GetThreadList()->SuspendAll(); 976 uint64_t start_time = NanoTime(); 977 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 978 VLOG(heap) << "Deflating " << count << " monitors took " 979 << PrettyDuration(NanoTime() - start_time); 980 runtime->GetThreadList()->ResumeAll(); 981 } 982 // Do a heap trim if it is needed. 983 Trim(); 984} 985 986void Heap::Trim() { 987 Thread* self = Thread::Current(); 988 { 989 MutexLock mu(self, *heap_trim_request_lock_); 990 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 991 return; 992 } 993 last_trim_time_ = NanoTime(); 994 heap_trim_request_pending_ = false; 995 } 996 { 997 // Need to do this before acquiring the locks since we don't want to get suspended while 998 // holding any locks. 999 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1000 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 1001 // trimming. 1002 MutexLock mu(self, *gc_complete_lock_); 1003 // Ensure there is only one GC at a time. 1004 WaitForGcToCompleteLocked(kGcCauseTrim, self); 1005 collector_type_running_ = kCollectorTypeHeapTrim; 1006 } 1007 uint64_t start_ns = NanoTime(); 1008 // Trim the managed spaces. 1009 uint64_t total_alloc_space_allocated = 0; 1010 uint64_t total_alloc_space_size = 0; 1011 uint64_t managed_reclaimed = 0; 1012 for (const auto& space : continuous_spaces_) { 1013 if (space->IsMallocSpace()) { 1014 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 1015 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 1016 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 1017 // for a long period of time. 1018 managed_reclaimed += malloc_space->Trim(); 1019 } 1020 total_alloc_space_size += malloc_space->Size(); 1021 } 1022 } 1023 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 1024 if (bump_pointer_space_ != nullptr) { 1025 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1026 } 1027 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1028 static_cast<float>(total_alloc_space_size); 1029 uint64_t gc_heap_end_ns = NanoTime(); 1030 // We never move things in the native heap, so we can finish the GC at this point. 1031 FinishGC(self, collector::kGcTypeNone); 1032 size_t native_reclaimed = 0; 1033 // Only trim the native heap if we don't care about pauses. 1034 if (!CareAboutPauseTimes()) { 1035#if defined(USE_DLMALLOC) 1036 // Trim the native heap. 1037 dlmalloc_trim(0); 1038 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1039#elif defined(USE_JEMALLOC) 1040 // Jemalloc does it's own internal trimming. 1041#else 1042 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1043#endif 1044 } 1045 uint64_t end_ns = NanoTime(); 1046 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1047 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1048 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1049 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1050 << "%."; 1051} 1052 1053bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1054 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1055 // taking the lock. 1056 if (obj == nullptr) { 1057 return true; 1058 } 1059 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1060} 1061 1062bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1063 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1064} 1065 1066bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1067 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1068 return false; 1069 } 1070 for (const auto& space : continuous_spaces_) { 1071 if (space->HasAddress(obj)) { 1072 return true; 1073 } 1074 } 1075 return false; 1076} 1077 1078bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1079 bool search_live_stack, bool sorted) { 1080 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1081 return false; 1082 } 1083 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1084 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1085 if (obj == klass) { 1086 // This case happens for java.lang.Class. 1087 return true; 1088 } 1089 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1090 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1091 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1092 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1093 return temp_space_->Contains(obj); 1094 } 1095 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1096 space::DiscontinuousSpace* d_space = nullptr; 1097 if (c_space != nullptr) { 1098 if (c_space->GetLiveBitmap()->Test(obj)) { 1099 return true; 1100 } 1101 } else { 1102 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1103 if (d_space != nullptr) { 1104 if (d_space->GetLiveBitmap()->Test(obj)) { 1105 return true; 1106 } 1107 } 1108 } 1109 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1110 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1111 if (i > 0) { 1112 NanoSleep(MsToNs(10)); 1113 } 1114 if (search_allocation_stack) { 1115 if (sorted) { 1116 if (allocation_stack_->ContainsSorted(obj)) { 1117 return true; 1118 } 1119 } else if (allocation_stack_->Contains(obj)) { 1120 return true; 1121 } 1122 } 1123 1124 if (search_live_stack) { 1125 if (sorted) { 1126 if (live_stack_->ContainsSorted(obj)) { 1127 return true; 1128 } 1129 } else if (live_stack_->Contains(obj)) { 1130 return true; 1131 } 1132 } 1133 } 1134 // We need to check the bitmaps again since there is a race where we mark something as live and 1135 // then clear the stack containing it. 1136 if (c_space != nullptr) { 1137 if (c_space->GetLiveBitmap()->Test(obj)) { 1138 return true; 1139 } 1140 } else { 1141 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1142 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1143 return true; 1144 } 1145 } 1146 return false; 1147} 1148 1149std::string Heap::DumpSpaces() const { 1150 std::ostringstream oss; 1151 DumpSpaces(oss); 1152 return oss.str(); 1153} 1154 1155void Heap::DumpSpaces(std::ostream& stream) const { 1156 for (const auto& space : continuous_spaces_) { 1157 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1158 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1159 stream << space << " " << *space << "\n"; 1160 if (live_bitmap != nullptr) { 1161 stream << live_bitmap << " " << *live_bitmap << "\n"; 1162 } 1163 if (mark_bitmap != nullptr) { 1164 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1165 } 1166 } 1167 for (const auto& space : discontinuous_spaces_) { 1168 stream << space << " " << *space << "\n"; 1169 } 1170} 1171 1172void Heap::VerifyObjectBody(mirror::Object* obj) { 1173 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1174 return; 1175 } 1176 1177 // Ignore early dawn of the universe verifications. 1178 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1179 return; 1180 } 1181 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1182 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1183 CHECK(c != nullptr) << "Null class in object " << obj; 1184 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1185 CHECK(VerifyClassClass(c)); 1186 1187 if (verify_object_mode_ > kVerifyObjectModeFast) { 1188 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1189 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1190 } 1191} 1192 1193void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1194 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1195} 1196 1197void Heap::VerifyHeap() { 1198 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1199 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1200} 1201 1202void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1203 // Use signed comparison since freed bytes can be negative when background compaction foreground 1204 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1205 // free list backed space typically increasing memory footprint due to padding and binning. 1206 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1207 // Note: This relies on 2s complement for handling negative freed_bytes. 1208 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1209 if (Runtime::Current()->HasStatsEnabled()) { 1210 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1211 thread_stats->freed_objects += freed_objects; 1212 thread_stats->freed_bytes += freed_bytes; 1213 // TODO: Do this concurrently. 1214 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1215 global_stats->freed_objects += freed_objects; 1216 global_stats->freed_bytes += freed_bytes; 1217 } 1218} 1219 1220space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1221 for (const auto& space : continuous_spaces_) { 1222 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1223 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1224 return space->AsContinuousSpace()->AsRosAllocSpace(); 1225 } 1226 } 1227 } 1228 return nullptr; 1229} 1230 1231mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1232 size_t alloc_size, size_t* bytes_allocated, 1233 size_t* usable_size, 1234 mirror::Class** klass) { 1235 bool was_default_allocator = allocator == GetCurrentAllocator(); 1236 DCHECK(klass != nullptr); 1237 StackHandleScope<1> hs(self); 1238 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1239 klass = nullptr; // Invalidate for safety. 1240 // The allocation failed. If the GC is running, block until it completes, and then retry the 1241 // allocation. 1242 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1243 if (last_gc != collector::kGcTypeNone) { 1244 // If we were the default allocator but the allocator changed while we were suspended, 1245 // abort the allocation. 1246 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1247 return nullptr; 1248 } 1249 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1250 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1251 usable_size); 1252 if (ptr != nullptr) { 1253 return ptr; 1254 } 1255 } 1256 1257 collector::GcType tried_type = next_gc_type_; 1258 const bool gc_ran = 1259 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1260 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1261 return nullptr; 1262 } 1263 if (gc_ran) { 1264 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1265 usable_size); 1266 if (ptr != nullptr) { 1267 return ptr; 1268 } 1269 } 1270 1271 // Loop through our different Gc types and try to Gc until we get enough free memory. 1272 for (collector::GcType gc_type : gc_plan_) { 1273 if (gc_type == tried_type) { 1274 continue; 1275 } 1276 // Attempt to run the collector, if we succeed, re-try the allocation. 1277 const bool gc_ran = 1278 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1279 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1280 return nullptr; 1281 } 1282 if (gc_ran) { 1283 // Did we free sufficient memory for the allocation to succeed? 1284 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1285 usable_size); 1286 if (ptr != nullptr) { 1287 return ptr; 1288 } 1289 } 1290 } 1291 // Allocations have failed after GCs; this is an exceptional state. 1292 // Try harder, growing the heap if necessary. 1293 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1294 usable_size); 1295 if (ptr != nullptr) { 1296 return ptr; 1297 } 1298 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1299 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1300 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1301 // OOME. 1302 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1303 << " allocation"; 1304 // TODO: Run finalization, but this may cause more allocations to occur. 1305 // We don't need a WaitForGcToComplete here either. 1306 DCHECK(!gc_plan_.empty()); 1307 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1308 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1309 return nullptr; 1310 } 1311 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1312 if (ptr == nullptr) { 1313 const uint64_t current_time = NanoTime(); 1314 switch (allocator) { 1315 case kAllocatorTypeRosAlloc: 1316 // Fall-through. 1317 case kAllocatorTypeDlMalloc: { 1318 if (use_homogeneous_space_compaction_for_oom_ && 1319 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1320 min_interval_homogeneous_space_compaction_by_oom_) { 1321 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1322 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1323 switch (result) { 1324 case HomogeneousSpaceCompactResult::kSuccess: 1325 // If the allocation succeeded, we delayed an oom. 1326 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1327 usable_size); 1328 if (ptr != nullptr) { 1329 count_delayed_oom_++; 1330 } 1331 break; 1332 case HomogeneousSpaceCompactResult::kErrorReject: 1333 // Reject due to disabled moving GC. 1334 break; 1335 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1336 // Throw OOM by default. 1337 break; 1338 default: { 1339 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1340 << static_cast<size_t>(result); 1341 } 1342 } 1343 // Always print that we ran homogeneous space compation since this can cause jank. 1344 VLOG(heap) << "Ran heap homogeneous space compaction, " 1345 << " requested defragmentation " 1346 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1347 << " performed defragmentation " 1348 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1349 << " ignored homogeneous space compaction " 1350 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1351 << " delayed count = " 1352 << count_delayed_oom_.LoadSequentiallyConsistent(); 1353 } 1354 break; 1355 } 1356 case kAllocatorTypeNonMoving: { 1357 // Try to transition the heap if the allocation failure was due to the space being full. 1358 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1359 // If we aren't out of memory then the OOM was probably from the non moving space being 1360 // full. Attempt to disable compaction and turn the main space into a non moving space. 1361 DisableMovingGc(); 1362 // If we are still a moving GC then something must have caused the transition to fail. 1363 if (IsMovingGc(collector_type_)) { 1364 MutexLock mu(self, *gc_complete_lock_); 1365 // If we couldn't disable moving GC, just throw OOME and return null. 1366 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1367 << disable_moving_gc_count_; 1368 } else { 1369 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1370 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1371 usable_size); 1372 } 1373 } 1374 break; 1375 } 1376 default: { 1377 // Do nothing for others allocators. 1378 } 1379 } 1380 } 1381 // If the allocation hasn't succeeded by this point, throw an OOM error. 1382 if (ptr == nullptr) { 1383 ThrowOutOfMemoryError(self, alloc_size, allocator); 1384 } 1385 return ptr; 1386} 1387 1388void Heap::SetTargetHeapUtilization(float target) { 1389 DCHECK_GT(target, 0.0f); // asserted in Java code 1390 DCHECK_LT(target, 1.0f); 1391 target_utilization_ = target; 1392} 1393 1394size_t Heap::GetObjectsAllocated() const { 1395 size_t total = 0; 1396 for (space::AllocSpace* space : alloc_spaces_) { 1397 total += space->GetObjectsAllocated(); 1398 } 1399 return total; 1400} 1401 1402uint64_t Heap::GetObjectsAllocatedEver() const { 1403 return GetObjectsFreedEver() + GetObjectsAllocated(); 1404} 1405 1406uint64_t Heap::GetBytesAllocatedEver() const { 1407 return GetBytesFreedEver() + GetBytesAllocated(); 1408} 1409 1410class InstanceCounter { 1411 public: 1412 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1413 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1414 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1415 } 1416 static void Callback(mirror::Object* obj, void* arg) 1417 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1418 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1419 mirror::Class* instance_class = obj->GetClass(); 1420 CHECK(instance_class != nullptr); 1421 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1422 if (instance_counter->use_is_assignable_from_) { 1423 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1424 ++instance_counter->counts_[i]; 1425 } 1426 } else if (instance_class == instance_counter->classes_[i]) { 1427 ++instance_counter->counts_[i]; 1428 } 1429 } 1430 } 1431 1432 private: 1433 const std::vector<mirror::Class*>& classes_; 1434 bool use_is_assignable_from_; 1435 uint64_t* const counts_; 1436 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1437}; 1438 1439void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1440 uint64_t* counts) { 1441 // Can't do any GC in this function since this may move classes. 1442 Thread* self = Thread::Current(); 1443 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1444 InstanceCounter counter(classes, use_is_assignable_from, counts); 1445 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1446 VisitObjects(InstanceCounter::Callback, &counter); 1447 self->EndAssertNoThreadSuspension(old_cause); 1448} 1449 1450class InstanceCollector { 1451 public: 1452 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1453 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1454 : class_(c), max_count_(max_count), instances_(instances) { 1455 } 1456 static void Callback(mirror::Object* obj, void* arg) 1457 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1458 DCHECK(arg != nullptr); 1459 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1460 mirror::Class* instance_class = obj->GetClass(); 1461 if (instance_class == instance_collector->class_) { 1462 if (instance_collector->max_count_ == 0 || 1463 instance_collector->instances_.size() < instance_collector->max_count_) { 1464 instance_collector->instances_.push_back(obj); 1465 } 1466 } 1467 } 1468 1469 private: 1470 mirror::Class* class_; 1471 uint32_t max_count_; 1472 std::vector<mirror::Object*>& instances_; 1473 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1474}; 1475 1476void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1477 std::vector<mirror::Object*>& instances) { 1478 // Can't do any GC in this function since this may move classes. 1479 Thread* self = Thread::Current(); 1480 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1481 InstanceCollector collector(c, max_count, instances); 1482 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1483 VisitObjects(&InstanceCollector::Callback, &collector); 1484 self->EndAssertNoThreadSuspension(old_cause); 1485} 1486 1487class ReferringObjectsFinder { 1488 public: 1489 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1490 std::vector<mirror::Object*>& referring_objects) 1491 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1492 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1493 } 1494 1495 static void Callback(mirror::Object* obj, void* arg) 1496 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1497 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1498 } 1499 1500 // For bitmap Visit. 1501 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1502 // annotalysis on visitors. 1503 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1504 o->VisitReferences<true>(*this, VoidFunctor()); 1505 } 1506 1507 // For Object::VisitReferences. 1508 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1509 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1510 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1511 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1512 referring_objects_.push_back(obj); 1513 } 1514 } 1515 1516 private: 1517 mirror::Object* object_; 1518 uint32_t max_count_; 1519 std::vector<mirror::Object*>& referring_objects_; 1520 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1521}; 1522 1523void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1524 std::vector<mirror::Object*>& referring_objects) { 1525 // Can't do any GC in this function since this may move the object o. 1526 Thread* self = Thread::Current(); 1527 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1528 ReferringObjectsFinder finder(o, max_count, referring_objects); 1529 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1530 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1531 self->EndAssertNoThreadSuspension(old_cause); 1532} 1533 1534void Heap::CollectGarbage(bool clear_soft_references) { 1535 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1536 // last GC will not have necessarily been cleared. 1537 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1538} 1539 1540HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1541 Thread* self = Thread::Current(); 1542 // Inc requested homogeneous space compaction. 1543 count_requested_homogeneous_space_compaction_++; 1544 // Store performed homogeneous space compaction at a new request arrival. 1545 ThreadList* tl = Runtime::Current()->GetThreadList(); 1546 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1547 Locks::mutator_lock_->AssertNotHeld(self); 1548 { 1549 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1550 MutexLock mu(self, *gc_complete_lock_); 1551 // Ensure there is only one GC at a time. 1552 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1553 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1554 // is non zero. 1555 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1556 // exit. 1557 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1558 !main_space_->CanMoveObjects()) { 1559 return HomogeneousSpaceCompactResult::kErrorReject; 1560 } 1561 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1562 } 1563 if (Runtime::Current()->IsShuttingDown(self)) { 1564 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1565 // cause objects to get finalized. 1566 FinishGC(self, collector::kGcTypeNone); 1567 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1568 } 1569 // Suspend all threads. 1570 tl->SuspendAll(); 1571 uint64_t start_time = NanoTime(); 1572 // Launch compaction. 1573 space::MallocSpace* to_space = main_space_backup_.release(); 1574 space::MallocSpace* from_space = main_space_; 1575 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1576 const uint64_t space_size_before_compaction = from_space->Size(); 1577 AddSpace(to_space); 1578 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1579 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1580 from_space->GetMemMap()->Protect(PROT_READ); 1581 const uint64_t space_size_after_compaction = to_space->Size(); 1582 main_space_ = to_space; 1583 main_space_backup_.reset(from_space); 1584 RemoveSpace(from_space); 1585 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1586 // Update performed homogeneous space compaction count. 1587 count_performed_homogeneous_space_compaction_++; 1588 // Print statics log and resume all threads. 1589 uint64_t duration = NanoTime() - start_time; 1590 VLOG(gc) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1591 << PrettySize(space_size_before_compaction) << " -> " 1592 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1593 << std::fixed << static_cast<double>(space_size_after_compaction) / 1594 static_cast<double>(space_size_before_compaction); 1595 tl->ResumeAll(); 1596 // Finish GC. 1597 reference_processor_.EnqueueClearedReferences(self); 1598 GrowForUtilization(semi_space_collector_); 1599 FinishGC(self, collector::kGcTypeFull); 1600 return HomogeneousSpaceCompactResult::kSuccess; 1601} 1602 1603 1604void Heap::TransitionCollector(CollectorType collector_type) { 1605 if (collector_type == collector_type_) { 1606 return; 1607 } 1608 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1609 << " -> " << static_cast<int>(collector_type); 1610 uint64_t start_time = NanoTime(); 1611 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1612 Runtime* const runtime = Runtime::Current(); 1613 ThreadList* const tl = runtime->GetThreadList(); 1614 Thread* const self = Thread::Current(); 1615 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1616 Locks::mutator_lock_->AssertNotHeld(self); 1617 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1618 // compacting_gc_disable_count_, this should rarely occurs). 1619 for (;;) { 1620 { 1621 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1622 MutexLock mu(self, *gc_complete_lock_); 1623 // Ensure there is only one GC at a time. 1624 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1625 // Currently we only need a heap transition if we switch from a moving collector to a 1626 // non-moving one, or visa versa. 1627 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1628 // If someone else beat us to it and changed the collector before we could, exit. 1629 // This is safe to do before the suspend all since we set the collector_type_running_ before 1630 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1631 // then it would get blocked on WaitForGcToCompleteLocked. 1632 if (collector_type == collector_type_) { 1633 return; 1634 } 1635 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1636 if (!copying_transition || disable_moving_gc_count_ == 0) { 1637 // TODO: Not hard code in semi-space collector? 1638 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1639 break; 1640 } 1641 } 1642 usleep(1000); 1643 } 1644 if (runtime->IsShuttingDown(self)) { 1645 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1646 // cause objects to get finalized. 1647 FinishGC(self, collector::kGcTypeNone); 1648 return; 1649 } 1650 tl->SuspendAll(); 1651 switch (collector_type) { 1652 case kCollectorTypeSS: { 1653 if (!IsMovingGc(collector_type_)) { 1654 // Create the bump pointer space from the backup space. 1655 CHECK(main_space_backup_ != nullptr); 1656 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1657 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1658 // pointer space last transition it will be protected. 1659 CHECK(mem_map != nullptr); 1660 mem_map->Protect(PROT_READ | PROT_WRITE); 1661 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1662 mem_map.release()); 1663 AddSpace(bump_pointer_space_); 1664 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1665 // Use the now empty main space mem map for the bump pointer temp space. 1666 mem_map.reset(main_space_->ReleaseMemMap()); 1667 // Unset the pointers just in case. 1668 if (dlmalloc_space_ == main_space_) { 1669 dlmalloc_space_ = nullptr; 1670 } else if (rosalloc_space_ == main_space_) { 1671 rosalloc_space_ = nullptr; 1672 } 1673 // Remove the main space so that we don't try to trim it, this doens't work for debug 1674 // builds since RosAlloc attempts to read the magic number from a protected page. 1675 RemoveSpace(main_space_); 1676 RemoveRememberedSet(main_space_); 1677 delete main_space_; // Delete the space since it has been removed. 1678 main_space_ = nullptr; 1679 RemoveRememberedSet(main_space_backup_.get()); 1680 main_space_backup_.reset(nullptr); // Deletes the space. 1681 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1682 mem_map.release()); 1683 AddSpace(temp_space_); 1684 } 1685 break; 1686 } 1687 case kCollectorTypeMS: 1688 // Fall through. 1689 case kCollectorTypeCMS: { 1690 if (IsMovingGc(collector_type_)) { 1691 CHECK(temp_space_ != nullptr); 1692 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1693 RemoveSpace(temp_space_); 1694 temp_space_ = nullptr; 1695 mem_map->Protect(PROT_READ | PROT_WRITE); 1696 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1697 mem_map->Size()); 1698 mem_map.release(); 1699 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1700 AddSpace(main_space_); 1701 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1702 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1703 RemoveSpace(bump_pointer_space_); 1704 bump_pointer_space_ = nullptr; 1705 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1706 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1707 if (kIsDebugBuild && kUseRosAlloc) { 1708 mem_map->Protect(PROT_READ | PROT_WRITE); 1709 } 1710 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1711 mem_map->Size(), mem_map->Size(), 1712 name, true)); 1713 if (kIsDebugBuild && kUseRosAlloc) { 1714 mem_map->Protect(PROT_NONE); 1715 } 1716 mem_map.release(); 1717 } 1718 break; 1719 } 1720 default: { 1721 LOG(FATAL) << "Attempted to transition to invalid collector type " 1722 << static_cast<size_t>(collector_type); 1723 break; 1724 } 1725 } 1726 ChangeCollector(collector_type); 1727 tl->ResumeAll(); 1728 // Can't call into java code with all threads suspended. 1729 reference_processor_.EnqueueClearedReferences(self); 1730 uint64_t duration = NanoTime() - start_time; 1731 GrowForUtilization(semi_space_collector_); 1732 FinishGC(self, collector::kGcTypeFull); 1733 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1734 int32_t delta_allocated = before_allocated - after_allocated; 1735 std::string saved_str; 1736 if (delta_allocated >= 0) { 1737 saved_str = " saved at least " + PrettySize(delta_allocated); 1738 } else { 1739 saved_str = " expanded " + PrettySize(-delta_allocated); 1740 } 1741 VLOG(gc) << "Heap transition to " << process_state_ << " took " 1742 << PrettyDuration(duration) << saved_str; 1743} 1744 1745void Heap::ChangeCollector(CollectorType collector_type) { 1746 // TODO: Only do this with all mutators suspended to avoid races. 1747 if (collector_type != collector_type_) { 1748 if (collector_type == kCollectorTypeMC) { 1749 // Don't allow mark compact unless support is compiled in. 1750 CHECK(kMarkCompactSupport); 1751 } 1752 collector_type_ = collector_type; 1753 gc_plan_.clear(); 1754 switch (collector_type_) { 1755 case kCollectorTypeCC: // Fall-through. 1756 case kCollectorTypeMC: // Fall-through. 1757 case kCollectorTypeSS: // Fall-through. 1758 case kCollectorTypeGSS: { 1759 gc_plan_.push_back(collector::kGcTypeFull); 1760 if (use_tlab_) { 1761 ChangeAllocator(kAllocatorTypeTLAB); 1762 } else { 1763 ChangeAllocator(kAllocatorTypeBumpPointer); 1764 } 1765 break; 1766 } 1767 case kCollectorTypeMS: { 1768 gc_plan_.push_back(collector::kGcTypeSticky); 1769 gc_plan_.push_back(collector::kGcTypePartial); 1770 gc_plan_.push_back(collector::kGcTypeFull); 1771 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1772 break; 1773 } 1774 case kCollectorTypeCMS: { 1775 gc_plan_.push_back(collector::kGcTypeSticky); 1776 gc_plan_.push_back(collector::kGcTypePartial); 1777 gc_plan_.push_back(collector::kGcTypeFull); 1778 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1779 break; 1780 } 1781 default: { 1782 LOG(FATAL) << "Unimplemented"; 1783 } 1784 } 1785 if (IsGcConcurrent()) { 1786 concurrent_start_bytes_ = 1787 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1788 } else { 1789 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1790 } 1791 } 1792} 1793 1794// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1795class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1796 public: 1797 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1798 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1799 } 1800 1801 void BuildBins(space::ContinuousSpace* space) { 1802 bin_live_bitmap_ = space->GetLiveBitmap(); 1803 bin_mark_bitmap_ = space->GetMarkBitmap(); 1804 BinContext context; 1805 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1806 context.collector_ = this; 1807 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1808 // Note: This requires traversing the space in increasing order of object addresses. 1809 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1810 // Add the last bin which spans after the last object to the end of the space. 1811 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1812 } 1813 1814 private: 1815 struct BinContext { 1816 uintptr_t prev_; // The end of the previous object. 1817 ZygoteCompactingCollector* collector_; 1818 }; 1819 // Maps from bin sizes to locations. 1820 std::multimap<size_t, uintptr_t> bins_; 1821 // Live bitmap of the space which contains the bins. 1822 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1823 // Mark bitmap of the space which contains the bins. 1824 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1825 1826 static void Callback(mirror::Object* obj, void* arg) 1827 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1828 DCHECK(arg != nullptr); 1829 BinContext* context = reinterpret_cast<BinContext*>(arg); 1830 ZygoteCompactingCollector* collector = context->collector_; 1831 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1832 size_t bin_size = object_addr - context->prev_; 1833 // Add the bin consisting of the end of the previous object to the start of the current object. 1834 collector->AddBin(bin_size, context->prev_); 1835 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1836 } 1837 1838 void AddBin(size_t size, uintptr_t position) { 1839 if (size != 0) { 1840 bins_.insert(std::make_pair(size, position)); 1841 } 1842 } 1843 1844 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1845 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1846 // allocator. 1847 return false; 1848 } 1849 1850 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1851 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1852 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1853 mirror::Object* forward_address; 1854 // Find the smallest bin which we can move obj in. 1855 auto it = bins_.lower_bound(object_size); 1856 if (it == bins_.end()) { 1857 // No available space in the bins, place it in the target space instead (grows the zygote 1858 // space). 1859 size_t bytes_allocated; 1860 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1861 if (to_space_live_bitmap_ != nullptr) { 1862 to_space_live_bitmap_->Set(forward_address); 1863 } else { 1864 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1865 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1866 } 1867 } else { 1868 size_t size = it->first; 1869 uintptr_t pos = it->second; 1870 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1871 forward_address = reinterpret_cast<mirror::Object*>(pos); 1872 // Set the live and mark bits so that sweeping system weaks works properly. 1873 bin_live_bitmap_->Set(forward_address); 1874 bin_mark_bitmap_->Set(forward_address); 1875 DCHECK_GE(size, object_size); 1876 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1877 } 1878 // Copy the object over to its new location. 1879 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1880 if (kUseBakerOrBrooksReadBarrier) { 1881 obj->AssertReadBarrierPointer(); 1882 if (kUseBrooksReadBarrier) { 1883 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1884 forward_address->SetReadBarrierPointer(forward_address); 1885 } 1886 forward_address->AssertReadBarrierPointer(); 1887 } 1888 return forward_address; 1889 } 1890}; 1891 1892void Heap::UnBindBitmaps() { 1893 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1894 for (const auto& space : GetContinuousSpaces()) { 1895 if (space->IsContinuousMemMapAllocSpace()) { 1896 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1897 if (alloc_space->HasBoundBitmaps()) { 1898 alloc_space->UnBindBitmaps(); 1899 } 1900 } 1901 } 1902} 1903 1904void Heap::PreZygoteFork() { 1905 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1906 Thread* self = Thread::Current(); 1907 MutexLock mu(self, zygote_creation_lock_); 1908 // Try to see if we have any Zygote spaces. 1909 if (have_zygote_space_) { 1910 return; 1911 } 1912 VLOG(heap) << "Starting PreZygoteFork"; 1913 // Trim the pages at the end of the non moving space. 1914 non_moving_space_->Trim(); 1915 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1916 // there. 1917 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1918 const bool same_space = non_moving_space_ == main_space_; 1919 if (kCompactZygote) { 1920 // Can't compact if the non moving space is the same as the main space. 1921 DCHECK(semi_space_collector_ != nullptr); 1922 // Temporarily disable rosalloc verification because the zygote 1923 // compaction will mess up the rosalloc internal metadata. 1924 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1925 ZygoteCompactingCollector zygote_collector(this); 1926 zygote_collector.BuildBins(non_moving_space_); 1927 // Create a new bump pointer space which we will compact into. 1928 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1929 non_moving_space_->Limit()); 1930 // Compact the bump pointer space to a new zygote bump pointer space. 1931 bool reset_main_space = false; 1932 if (IsMovingGc(collector_type_)) { 1933 zygote_collector.SetFromSpace(bump_pointer_space_); 1934 } else { 1935 CHECK(main_space_ != nullptr); 1936 // Copy from the main space. 1937 zygote_collector.SetFromSpace(main_space_); 1938 reset_main_space = true; 1939 } 1940 zygote_collector.SetToSpace(&target_space); 1941 zygote_collector.SetSwapSemiSpaces(false); 1942 zygote_collector.Run(kGcCauseCollectorTransition, false); 1943 if (reset_main_space) { 1944 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1945 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1946 MemMap* mem_map = main_space_->ReleaseMemMap(); 1947 RemoveSpace(main_space_); 1948 space::Space* old_main_space = main_space_; 1949 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1950 delete old_main_space; 1951 AddSpace(main_space_); 1952 } else { 1953 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1954 } 1955 if (temp_space_ != nullptr) { 1956 CHECK(temp_space_->IsEmpty()); 1957 } 1958 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1959 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1960 // Update the end and write out image. 1961 non_moving_space_->SetEnd(target_space.End()); 1962 non_moving_space_->SetLimit(target_space.Limit()); 1963 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1964 } 1965 // Change the collector to the post zygote one. 1966 ChangeCollector(foreground_collector_type_); 1967 // Save the old space so that we can remove it after we complete creating the zygote space. 1968 space::MallocSpace* old_alloc_space = non_moving_space_; 1969 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1970 // the remaining available space. 1971 // Remove the old space before creating the zygote space since creating the zygote space sets 1972 // the old alloc space's bitmaps to nullptr. 1973 RemoveSpace(old_alloc_space); 1974 if (collector::SemiSpace::kUseRememberedSet) { 1975 // Sanity bound check. 1976 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1977 // Remove the remembered set for the now zygote space (the old 1978 // non-moving space). Note now that we have compacted objects into 1979 // the zygote space, the data in the remembered set is no longer 1980 // needed. The zygote space will instead have a mod-union table 1981 // from this point on. 1982 RemoveRememberedSet(old_alloc_space); 1983 } 1984 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1985 low_memory_mode_, 1986 &non_moving_space_); 1987 CHECK(!non_moving_space_->CanMoveObjects()); 1988 if (same_space) { 1989 main_space_ = non_moving_space_; 1990 SetSpaceAsDefault(main_space_); 1991 } 1992 delete old_alloc_space; 1993 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1994 AddSpace(zygote_space); 1995 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1996 AddSpace(non_moving_space_); 1997 have_zygote_space_ = true; 1998 // Enable large object space allocations. 1999 large_object_threshold_ = kDefaultLargeObjectThreshold; 2000 // Create the zygote space mod union table. 2001 accounting::ModUnionTable* mod_union_table = 2002 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 2003 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 2004 AddModUnionTable(mod_union_table); 2005 if (collector::SemiSpace::kUseRememberedSet) { 2006 // Add a new remembered set for the post-zygote non-moving space. 2007 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 2008 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 2009 non_moving_space_); 2010 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 2011 << "Failed to create post-zygote non-moving space remembered set"; 2012 AddRememberedSet(post_zygote_non_moving_space_rem_set); 2013 } 2014} 2015 2016void Heap::FlushAllocStack() { 2017 MarkAllocStackAsLive(allocation_stack_.get()); 2018 allocation_stack_->Reset(); 2019} 2020 2021void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2022 accounting::ContinuousSpaceBitmap* bitmap2, 2023 accounting::LargeObjectBitmap* large_objects, 2024 accounting::ObjectStack* stack) { 2025 DCHECK(bitmap1 != nullptr); 2026 DCHECK(bitmap2 != nullptr); 2027 mirror::Object** limit = stack->End(); 2028 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2029 const mirror::Object* obj = *it; 2030 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2031 if (bitmap1->HasAddress(obj)) { 2032 bitmap1->Set(obj); 2033 } else if (bitmap2->HasAddress(obj)) { 2034 bitmap2->Set(obj); 2035 } else { 2036 large_objects->Set(obj); 2037 } 2038 } 2039 } 2040} 2041 2042void Heap::SwapSemiSpaces() { 2043 CHECK(bump_pointer_space_ != nullptr); 2044 CHECK(temp_space_ != nullptr); 2045 std::swap(bump_pointer_space_, temp_space_); 2046} 2047 2048void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2049 space::ContinuousMemMapAllocSpace* source_space, 2050 GcCause gc_cause) { 2051 CHECK(kMovingCollector); 2052 if (target_space != source_space) { 2053 // Don't swap spaces since this isn't a typical semi space collection. 2054 semi_space_collector_->SetSwapSemiSpaces(false); 2055 semi_space_collector_->SetFromSpace(source_space); 2056 semi_space_collector_->SetToSpace(target_space); 2057 semi_space_collector_->Run(gc_cause, false); 2058 } else { 2059 CHECK(target_space->IsBumpPointerSpace()) 2060 << "In-place compaction is only supported for bump pointer spaces"; 2061 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2062 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2063 } 2064} 2065 2066collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2067 bool clear_soft_references) { 2068 Thread* self = Thread::Current(); 2069 Runtime* runtime = Runtime::Current(); 2070 // If the heap can't run the GC, silently fail and return that no GC was run. 2071 switch (gc_type) { 2072 case collector::kGcTypePartial: { 2073 if (!have_zygote_space_) { 2074 return collector::kGcTypeNone; 2075 } 2076 break; 2077 } 2078 default: { 2079 // Other GC types don't have any special cases which makes them not runnable. The main case 2080 // here is full GC. 2081 } 2082 } 2083 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2084 Locks::mutator_lock_->AssertNotHeld(self); 2085 if (self->IsHandlingStackOverflow()) { 2086 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2087 } 2088 bool compacting_gc; 2089 { 2090 gc_complete_lock_->AssertNotHeld(self); 2091 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2092 MutexLock mu(self, *gc_complete_lock_); 2093 // Ensure there is only one GC at a time. 2094 WaitForGcToCompleteLocked(gc_cause, self); 2095 compacting_gc = IsMovingGc(collector_type_); 2096 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2097 if (compacting_gc && disable_moving_gc_count_ != 0) { 2098 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2099 return collector::kGcTypeNone; 2100 } 2101 collector_type_running_ = collector_type_; 2102 } 2103 2104 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2105 ++runtime->GetStats()->gc_for_alloc_count; 2106 ++self->GetStats()->gc_for_alloc_count; 2107 } 2108 uint64_t gc_start_time_ns = NanoTime(); 2109 uint64_t gc_start_size = GetBytesAllocated(); 2110 // Approximate allocation rate in bytes / second. 2111 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2112 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2113 if (LIKELY(ms_delta != 0)) { 2114 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2115 ATRACE_INT("Allocation rate KB/s", allocation_rate_ / KB); 2116 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2117 } 2118 2119 DCHECK_LT(gc_type, collector::kGcTypeMax); 2120 DCHECK_NE(gc_type, collector::kGcTypeNone); 2121 2122 collector::GarbageCollector* collector = nullptr; 2123 // TODO: Clean this up. 2124 if (compacting_gc) { 2125 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2126 current_allocator_ == kAllocatorTypeTLAB); 2127 switch (collector_type_) { 2128 case kCollectorTypeSS: 2129 // Fall-through. 2130 case kCollectorTypeGSS: 2131 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2132 semi_space_collector_->SetToSpace(temp_space_); 2133 semi_space_collector_->SetSwapSemiSpaces(true); 2134 collector = semi_space_collector_; 2135 break; 2136 case kCollectorTypeCC: 2137 collector = concurrent_copying_collector_; 2138 break; 2139 case kCollectorTypeMC: 2140 mark_compact_collector_->SetSpace(bump_pointer_space_); 2141 collector = mark_compact_collector_; 2142 break; 2143 default: 2144 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2145 } 2146 if (collector != mark_compact_collector_) { 2147 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2148 CHECK(temp_space_->IsEmpty()); 2149 } 2150 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2151 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2152 current_allocator_ == kAllocatorTypeDlMalloc) { 2153 collector = FindCollectorByGcType(gc_type); 2154 } else { 2155 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2156 } 2157 CHECK(collector != nullptr) 2158 << "Could not find garbage collector with collector_type=" 2159 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2160 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2161 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2162 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2163 RequestHeapTrim(); 2164 // Enqueue cleared references. 2165 reference_processor_.EnqueueClearedReferences(self); 2166 // Grow the heap so that we know when to perform the next GC. 2167 GrowForUtilization(collector); 2168 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2169 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2170 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2171 // (mutator time blocked >= long_pause_log_threshold_). 2172 bool log_gc = gc_cause == kGcCauseExplicit; 2173 if (!log_gc && CareAboutPauseTimes()) { 2174 // GC for alloc pauses the allocating thread, so consider it as a pause. 2175 log_gc = duration > long_gc_log_threshold_ || 2176 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2177 for (uint64_t pause : pause_times) { 2178 log_gc = log_gc || pause >= long_pause_log_threshold_; 2179 } 2180 } 2181 if (log_gc) { 2182 const size_t percent_free = GetPercentFree(); 2183 const size_t current_heap_size = GetBytesAllocated(); 2184 const size_t total_memory = GetTotalMemory(); 2185 std::ostringstream pause_string; 2186 for (size_t i = 0; i < pause_times.size(); ++i) { 2187 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2188 << ((i != pause_times.size() - 1) ? "," : ""); 2189 } 2190 LOG(INFO) << gc_cause << " " << collector->GetName() 2191 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2192 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2193 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2194 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2195 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2196 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2197 << " total " << PrettyDuration((duration / 1000) * 1000); 2198 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2199 } 2200 FinishGC(self, gc_type); 2201 // Inform DDMS that a GC completed. 2202 Dbg::GcDidFinish(); 2203 return gc_type; 2204} 2205 2206void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2207 MutexLock mu(self, *gc_complete_lock_); 2208 collector_type_running_ = kCollectorTypeNone; 2209 if (gc_type != collector::kGcTypeNone) { 2210 last_gc_type_ = gc_type; 2211 } 2212 // Wake anyone who may have been waiting for the GC to complete. 2213 gc_complete_cond_->Broadcast(self); 2214} 2215 2216static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2217 RootType /*root_type*/) { 2218 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2219 if (*root == obj) { 2220 LOG(INFO) << "Object " << obj << " is a root"; 2221 } 2222} 2223 2224class ScanVisitor { 2225 public: 2226 void operator()(const mirror::Object* obj) const { 2227 LOG(ERROR) << "Would have rescanned object " << obj; 2228 } 2229}; 2230 2231// Verify a reference from an object. 2232class VerifyReferenceVisitor { 2233 public: 2234 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2235 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2236 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2237 2238 size_t GetFailureCount() const { 2239 return fail_count_->LoadSequentiallyConsistent(); 2240 } 2241 2242 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2243 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2244 if (verify_referent_) { 2245 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2246 } 2247 } 2248 2249 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2250 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2251 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2252 } 2253 2254 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2255 return heap_->IsLiveObjectLocked(obj, true, false, true); 2256 } 2257 2258 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2259 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2260 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2261 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2262 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2263 << " thread_id= " << thread_id << " root_type= " << root_type; 2264 } 2265 } 2266 2267 private: 2268 // TODO: Fix the no thread safety analysis. 2269 // Returns false on failure. 2270 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2271 NO_THREAD_SAFETY_ANALYSIS { 2272 if (ref == nullptr || IsLive(ref)) { 2273 // Verify that the reference is live. 2274 return true; 2275 } 2276 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2277 // Print message on only on first failure to prevent spam. 2278 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2279 } 2280 if (obj != nullptr) { 2281 // Only do this part for non roots. 2282 accounting::CardTable* card_table = heap_->GetCardTable(); 2283 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2284 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2285 byte* card_addr = card_table->CardFromAddr(obj); 2286 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2287 << offset << "\n card value = " << static_cast<int>(*card_addr); 2288 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2289 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2290 } else { 2291 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2292 } 2293 2294 // Attempt to find the class inside of the recently freed objects. 2295 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2296 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2297 space::MallocSpace* space = ref_space->AsMallocSpace(); 2298 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2299 if (ref_class != nullptr) { 2300 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2301 << PrettyClass(ref_class); 2302 } else { 2303 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2304 } 2305 } 2306 2307 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2308 ref->GetClass()->IsClass()) { 2309 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2310 } else { 2311 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2312 << ") is not a valid heap address"; 2313 } 2314 2315 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2316 void* cover_begin = card_table->AddrFromCard(card_addr); 2317 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2318 accounting::CardTable::kCardSize); 2319 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2320 << "-" << cover_end; 2321 accounting::ContinuousSpaceBitmap* bitmap = 2322 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2323 2324 if (bitmap == nullptr) { 2325 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2326 if (!VerifyClassClass(obj->GetClass())) { 2327 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2328 } 2329 } else { 2330 // Print out how the object is live. 2331 if (bitmap->Test(obj)) { 2332 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2333 } 2334 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2335 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2336 } 2337 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2338 LOG(ERROR) << "Object " << obj << " found in live stack"; 2339 } 2340 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2341 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2342 } 2343 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2344 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2345 } 2346 // Attempt to see if the card table missed the reference. 2347 ScanVisitor scan_visitor; 2348 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2349 card_table->Scan(bitmap, byte_cover_begin, 2350 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2351 } 2352 2353 // Search to see if any of the roots reference our object. 2354 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2355 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2356 2357 // Search to see if any of the roots reference our reference. 2358 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2359 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2360 } 2361 return false; 2362 } 2363 2364 Heap* const heap_; 2365 Atomic<size_t>* const fail_count_; 2366 const bool verify_referent_; 2367}; 2368 2369// Verify all references within an object, for use with HeapBitmap::Visit. 2370class VerifyObjectVisitor { 2371 public: 2372 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2373 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2374 } 2375 2376 void operator()(mirror::Object* obj) const 2377 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2378 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2379 // be live or else how did we find it in the live bitmap? 2380 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2381 // The class doesn't count as a reference but we should verify it anyways. 2382 obj->VisitReferences<true>(visitor, visitor); 2383 } 2384 2385 static void VisitCallback(mirror::Object* obj, void* arg) 2386 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2387 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2388 visitor->operator()(obj); 2389 } 2390 2391 size_t GetFailureCount() const { 2392 return fail_count_->LoadSequentiallyConsistent(); 2393 } 2394 2395 private: 2396 Heap* const heap_; 2397 Atomic<size_t>* const fail_count_; 2398 const bool verify_referent_; 2399}; 2400 2401void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2402 // Slow path, the allocation stack push back must have already failed. 2403 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2404 do { 2405 // TODO: Add handle VerifyObject. 2406 StackHandleScope<1> hs(self); 2407 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2408 // Push our object into the reserve region of the allocaiton stack. This is only required due 2409 // to heap verification requiring that roots are live (either in the live bitmap or in the 2410 // allocation stack). 2411 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2412 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2413 } while (!allocation_stack_->AtomicPushBack(*obj)); 2414} 2415 2416void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2417 // Slow path, the allocation stack push back must have already failed. 2418 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2419 mirror::Object** start_address; 2420 mirror::Object** end_address; 2421 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2422 &end_address)) { 2423 // TODO: Add handle VerifyObject. 2424 StackHandleScope<1> hs(self); 2425 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2426 // Push our object into the reserve region of the allocaiton stack. This is only required due 2427 // to heap verification requiring that roots are live (either in the live bitmap or in the 2428 // allocation stack). 2429 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2430 // Push into the reserve allocation stack. 2431 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2432 } 2433 self->SetThreadLocalAllocationStack(start_address, end_address); 2434 // Retry on the new thread-local allocation stack. 2435 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2436} 2437 2438// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2439size_t Heap::VerifyHeapReferences(bool verify_referents) { 2440 Thread* self = Thread::Current(); 2441 Locks::mutator_lock_->AssertExclusiveHeld(self); 2442 // Lets sort our allocation stacks so that we can efficiently binary search them. 2443 allocation_stack_->Sort(); 2444 live_stack_->Sort(); 2445 // Since we sorted the allocation stack content, need to revoke all 2446 // thread-local allocation stacks. 2447 RevokeAllThreadLocalAllocationStacks(self); 2448 Atomic<size_t> fail_count_(0); 2449 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2450 // Verify objects in the allocation stack since these will be objects which were: 2451 // 1. Allocated prior to the GC (pre GC verification). 2452 // 2. Allocated during the GC (pre sweep GC verification). 2453 // We don't want to verify the objects in the live stack since they themselves may be 2454 // pointing to dead objects if they are not reachable. 2455 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2456 // Verify the roots: 2457 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2458 if (visitor.GetFailureCount() > 0) { 2459 // Dump mod-union tables. 2460 for (const auto& table_pair : mod_union_tables_) { 2461 accounting::ModUnionTable* mod_union_table = table_pair.second; 2462 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2463 } 2464 // Dump remembered sets. 2465 for (const auto& table_pair : remembered_sets_) { 2466 accounting::RememberedSet* remembered_set = table_pair.second; 2467 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2468 } 2469 DumpSpaces(LOG(ERROR)); 2470 } 2471 return visitor.GetFailureCount(); 2472} 2473 2474class VerifyReferenceCardVisitor { 2475 public: 2476 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2477 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2478 Locks::heap_bitmap_lock_) 2479 : heap_(heap), failed_(failed) { 2480 } 2481 2482 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2483 // annotalysis on visitors. 2484 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2485 NO_THREAD_SAFETY_ANALYSIS { 2486 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2487 // Filter out class references since changing an object's class does not mark the card as dirty. 2488 // Also handles large objects, since the only reference they hold is a class reference. 2489 if (ref != nullptr && !ref->IsClass()) { 2490 accounting::CardTable* card_table = heap_->GetCardTable(); 2491 // If the object is not dirty and it is referencing something in the live stack other than 2492 // class, then it must be on a dirty card. 2493 if (!card_table->AddrIsInCardTable(obj)) { 2494 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2495 *failed_ = true; 2496 } else if (!card_table->IsDirty(obj)) { 2497 // TODO: Check mod-union tables. 2498 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2499 // kCardDirty - 1 if it didnt get touched since we aged it. 2500 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2501 if (live_stack->ContainsSorted(ref)) { 2502 if (live_stack->ContainsSorted(obj)) { 2503 LOG(ERROR) << "Object " << obj << " found in live stack"; 2504 } 2505 if (heap_->GetLiveBitmap()->Test(obj)) { 2506 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2507 } 2508 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2509 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2510 2511 // Print which field of the object is dead. 2512 if (!obj->IsObjectArray()) { 2513 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2514 CHECK(klass != NULL); 2515 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2516 : klass->GetIFields(); 2517 CHECK(fields != NULL); 2518 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2519 mirror::ArtField* cur = fields->Get(i); 2520 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2521 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2522 << PrettyField(cur); 2523 break; 2524 } 2525 } 2526 } else { 2527 mirror::ObjectArray<mirror::Object>* object_array = 2528 obj->AsObjectArray<mirror::Object>(); 2529 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2530 if (object_array->Get(i) == ref) { 2531 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2532 } 2533 } 2534 } 2535 2536 *failed_ = true; 2537 } 2538 } 2539 } 2540 } 2541 2542 private: 2543 Heap* const heap_; 2544 bool* const failed_; 2545}; 2546 2547class VerifyLiveStackReferences { 2548 public: 2549 explicit VerifyLiveStackReferences(Heap* heap) 2550 : heap_(heap), 2551 failed_(false) {} 2552 2553 void operator()(mirror::Object* obj) const 2554 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2555 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2556 obj->VisitReferences<true>(visitor, VoidFunctor()); 2557 } 2558 2559 bool Failed() const { 2560 return failed_; 2561 } 2562 2563 private: 2564 Heap* const heap_; 2565 bool failed_; 2566}; 2567 2568bool Heap::VerifyMissingCardMarks() { 2569 Thread* self = Thread::Current(); 2570 Locks::mutator_lock_->AssertExclusiveHeld(self); 2571 // We need to sort the live stack since we binary search it. 2572 live_stack_->Sort(); 2573 // Since we sorted the allocation stack content, need to revoke all 2574 // thread-local allocation stacks. 2575 RevokeAllThreadLocalAllocationStacks(self); 2576 VerifyLiveStackReferences visitor(this); 2577 GetLiveBitmap()->Visit(visitor); 2578 // We can verify objects in the live stack since none of these should reference dead objects. 2579 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2580 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2581 visitor(*it); 2582 } 2583 } 2584 return !visitor.Failed(); 2585} 2586 2587void Heap::SwapStacks(Thread* self) { 2588 if (kUseThreadLocalAllocationStack) { 2589 live_stack_->AssertAllZero(); 2590 } 2591 allocation_stack_.swap(live_stack_); 2592} 2593 2594void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2595 // This must be called only during the pause. 2596 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2597 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2598 MutexLock mu2(self, *Locks::thread_list_lock_); 2599 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2600 for (Thread* t : thread_list) { 2601 t->RevokeThreadLocalAllocationStack(); 2602 } 2603} 2604 2605void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2606 if (kIsDebugBuild) { 2607 if (bump_pointer_space_ != nullptr) { 2608 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2609 } 2610 } 2611} 2612 2613accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2614 auto it = mod_union_tables_.find(space); 2615 if (it == mod_union_tables_.end()) { 2616 return nullptr; 2617 } 2618 return it->second; 2619} 2620 2621accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2622 auto it = remembered_sets_.find(space); 2623 if (it == remembered_sets_.end()) { 2624 return nullptr; 2625 } 2626 return it->second; 2627} 2628 2629void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2630 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2631 // Clear cards and keep track of cards cleared in the mod-union table. 2632 for (const auto& space : continuous_spaces_) { 2633 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2634 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2635 if (table != nullptr) { 2636 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2637 "ImageModUnionClearCards"; 2638 TimingLogger::ScopedTiming t(name, timings); 2639 table->ClearCards(); 2640 } else if (use_rem_sets && rem_set != nullptr) { 2641 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2642 << static_cast<int>(collector_type_); 2643 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2644 rem_set->ClearCards(); 2645 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2646 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2647 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2648 // were dirty before the GC started. 2649 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2650 // -> clean(cleaning thread). 2651 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2652 // roots and then we scan / update mod union tables after. We will always scan either card. 2653 // If we end up with the non aged card, we scan it it in the pause. 2654 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2655 VoidFunctor()); 2656 } 2657 } 2658} 2659 2660static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2661} 2662 2663void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2664 Thread* const self = Thread::Current(); 2665 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2666 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2667 if (verify_pre_gc_heap_) { 2668 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2669 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2670 size_t failures = VerifyHeapReferences(); 2671 if (failures > 0) { 2672 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2673 << " failures"; 2674 } 2675 } 2676 // Check that all objects which reference things in the live stack are on dirty cards. 2677 if (verify_missing_card_marks_) { 2678 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2679 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2680 SwapStacks(self); 2681 // Sort the live stack so that we can quickly binary search it later. 2682 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2683 << " missing card mark verification failed\n" << DumpSpaces(); 2684 SwapStacks(self); 2685 } 2686 if (verify_mod_union_table_) { 2687 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2688 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2689 for (const auto& table_pair : mod_union_tables_) { 2690 accounting::ModUnionTable* mod_union_table = table_pair.second; 2691 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2692 mod_union_table->Verify(); 2693 } 2694 } 2695} 2696 2697void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2698 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2699 collector::GarbageCollector::ScopedPause pause(gc); 2700 PreGcVerificationPaused(gc); 2701 } 2702} 2703 2704void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2705 // TODO: Add a new runtime option for this? 2706 if (verify_pre_gc_rosalloc_) { 2707 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2708 } 2709} 2710 2711void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2712 Thread* const self = Thread::Current(); 2713 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2714 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2715 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2716 // reachable objects. 2717 if (verify_pre_sweeping_heap_) { 2718 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2719 CHECK_NE(self->GetState(), kRunnable); 2720 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2721 // Swapping bound bitmaps does nothing. 2722 gc->SwapBitmaps(); 2723 // Pass in false since concurrent reference processing can mean that the reference referents 2724 // may point to dead objects at the point which PreSweepingGcVerification is called. 2725 size_t failures = VerifyHeapReferences(false); 2726 if (failures > 0) { 2727 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2728 << " failures"; 2729 } 2730 gc->SwapBitmaps(); 2731 } 2732 if (verify_pre_sweeping_rosalloc_) { 2733 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2734 } 2735} 2736 2737void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2738 // Only pause if we have to do some verification. 2739 Thread* const self = Thread::Current(); 2740 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2741 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2742 if (verify_system_weaks_) { 2743 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2744 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2745 mark_sweep->VerifySystemWeaks(); 2746 } 2747 if (verify_post_gc_rosalloc_) { 2748 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2749 } 2750 if (verify_post_gc_heap_) { 2751 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2752 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2753 size_t failures = VerifyHeapReferences(); 2754 if (failures > 0) { 2755 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2756 << " failures"; 2757 } 2758 } 2759} 2760 2761void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2762 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2763 collector::GarbageCollector::ScopedPause pause(gc); 2764 PostGcVerificationPaused(gc); 2765 } 2766} 2767 2768void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2769 TimingLogger::ScopedTiming t(name, timings); 2770 for (const auto& space : continuous_spaces_) { 2771 if (space->IsRosAllocSpace()) { 2772 VLOG(heap) << name << " : " << space->GetName(); 2773 space->AsRosAllocSpace()->Verify(); 2774 } 2775 } 2776} 2777 2778collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2779 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2780 MutexLock mu(self, *gc_complete_lock_); 2781 return WaitForGcToCompleteLocked(cause, self); 2782} 2783 2784collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2785 collector::GcType last_gc_type = collector::kGcTypeNone; 2786 uint64_t wait_start = NanoTime(); 2787 while (collector_type_running_ != kCollectorTypeNone) { 2788 ATRACE_BEGIN("GC: Wait For Completion"); 2789 // We must wait, change thread state then sleep on gc_complete_cond_; 2790 gc_complete_cond_->Wait(self); 2791 last_gc_type = last_gc_type_; 2792 ATRACE_END(); 2793 } 2794 uint64_t wait_time = NanoTime() - wait_start; 2795 total_wait_time_ += wait_time; 2796 if (wait_time > long_pause_log_threshold_) { 2797 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2798 << " for cause " << cause; 2799 } 2800 return last_gc_type; 2801} 2802 2803void Heap::DumpForSigQuit(std::ostream& os) { 2804 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2805 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2806 DumpGcPerformanceInfo(os); 2807} 2808 2809size_t Heap::GetPercentFree() { 2810 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2811} 2812 2813void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2814 if (max_allowed_footprint > GetMaxMemory()) { 2815 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2816 << PrettySize(GetMaxMemory()); 2817 max_allowed_footprint = GetMaxMemory(); 2818 } 2819 max_allowed_footprint_ = max_allowed_footprint; 2820} 2821 2822bool Heap::IsMovableObject(const mirror::Object* obj) const { 2823 if (kMovingCollector) { 2824 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2825 if (space != nullptr) { 2826 // TODO: Check large object? 2827 return space->CanMoveObjects(); 2828 } 2829 } 2830 return false; 2831} 2832 2833void Heap::UpdateMaxNativeFootprint() { 2834 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2835 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2836 size_t target_size = native_size / GetTargetHeapUtilization(); 2837 if (target_size > native_size + max_free_) { 2838 target_size = native_size + max_free_; 2839 } else if (target_size < native_size + min_free_) { 2840 target_size = native_size + min_free_; 2841 } 2842 native_footprint_gc_watermark_ = target_size; 2843 native_footprint_limit_ = 2 * target_size - native_size; 2844} 2845 2846collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2847 for (const auto& collector : garbage_collectors_) { 2848 if (collector->GetCollectorType() == collector_type_ && 2849 collector->GetGcType() == gc_type) { 2850 return collector; 2851 } 2852 } 2853 return nullptr; 2854} 2855 2856double Heap::HeapGrowthMultiplier() const { 2857 // If we don't care about pause times we are background, so return 1.0. 2858 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2859 return 1.0; 2860 } 2861 return foreground_heap_growth_multiplier_; 2862} 2863 2864void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2865 // We know what our utilization is at this moment. 2866 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2867 const uint64_t bytes_allocated = GetBytesAllocated(); 2868 last_gc_size_ = bytes_allocated; 2869 last_gc_time_ns_ = NanoTime(); 2870 uint64_t target_size; 2871 collector::GcType gc_type = collector_ran->GetGcType(); 2872 if (gc_type != collector::kGcTypeSticky) { 2873 // Grow the heap for non sticky GC. 2874 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2875 // foreground. 2876 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2877 CHECK_GE(delta, 0); 2878 target_size = bytes_allocated + delta * multiplier; 2879 target_size = std::min(target_size, 2880 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2881 target_size = std::max(target_size, 2882 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2883 native_need_to_run_finalization_ = true; 2884 next_gc_type_ = collector::kGcTypeSticky; 2885 } else { 2886 collector::GcType non_sticky_gc_type = 2887 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2888 // Find what the next non sticky collector will be. 2889 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2890 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2891 // do another sticky collection next. 2892 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2893 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2894 // if the sticky GC throughput always remained >= the full/partial throughput. 2895 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2896 non_sticky_collector->GetEstimatedMeanThroughput() && 2897 non_sticky_collector->NumberOfIterations() > 0 && 2898 bytes_allocated <= max_allowed_footprint_) { 2899 next_gc_type_ = collector::kGcTypeSticky; 2900 } else { 2901 next_gc_type_ = non_sticky_gc_type; 2902 } 2903 // If we have freed enough memory, shrink the heap back down. 2904 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2905 target_size = bytes_allocated + max_free_; 2906 } else { 2907 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2908 } 2909 } 2910 if (!ignore_max_footprint_) { 2911 SetIdealFootprint(target_size); 2912 if (IsGcConcurrent()) { 2913 // Calculate when to perform the next ConcurrentGC. 2914 // Calculate the estimated GC duration. 2915 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2916 // Estimate how many remaining bytes we will have when we need to start the next GC. 2917 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2918 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2919 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2920 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2921 // A never going to happen situation that from the estimated allocation rate we will exceed 2922 // the applications entire footprint with the given estimated allocation rate. Schedule 2923 // another GC nearly straight away. 2924 remaining_bytes = kMinConcurrentRemainingBytes; 2925 } 2926 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2927 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2928 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2929 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2930 // right away. 2931 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2932 static_cast<size_t>(bytes_allocated)); 2933 } 2934 } 2935} 2936 2937void Heap::ClearGrowthLimit() { 2938 growth_limit_ = capacity_; 2939 non_moving_space_->ClearGrowthLimit(); 2940} 2941 2942void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2943 ScopedObjectAccess soa(self); 2944 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2945 jvalue args[1]; 2946 args[0].l = arg.get(); 2947 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2948 // Restore object in case it gets moved. 2949 *object = soa.Decode<mirror::Object*>(arg.get()); 2950} 2951 2952void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2953 StackHandleScope<1> hs(self); 2954 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2955 RequestConcurrentGC(self); 2956} 2957 2958void Heap::RequestConcurrentGC(Thread* self) { 2959 // Make sure that we can do a concurrent GC. 2960 Runtime* runtime = Runtime::Current(); 2961 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2962 self->IsHandlingStackOverflow()) { 2963 return; 2964 } 2965 // We already have a request pending, no reason to start more until we update 2966 // concurrent_start_bytes_. 2967 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2968 JNIEnv* env = self->GetJniEnv(); 2969 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2970 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2971 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2972 WellKnownClasses::java_lang_Daemons_requestGC); 2973 CHECK(!env->ExceptionCheck()); 2974} 2975 2976void Heap::ConcurrentGC(Thread* self) { 2977 if (Runtime::Current()->IsShuttingDown(self)) { 2978 return; 2979 } 2980 // Wait for any GCs currently running to finish. 2981 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2982 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2983 // instead. E.g. can't do partial, so do full instead. 2984 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2985 collector::kGcTypeNone) { 2986 for (collector::GcType gc_type : gc_plan_) { 2987 // Attempt to run the collector, if we succeed, we are done. 2988 if (gc_type > next_gc_type_ && 2989 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2990 break; 2991 } 2992 } 2993 } 2994 } 2995} 2996 2997void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2998 Thread* self = Thread::Current(); 2999 { 3000 MutexLock mu(self, *heap_trim_request_lock_); 3001 if (desired_collector_type_ == desired_collector_type) { 3002 return; 3003 } 3004 heap_transition_or_trim_target_time_ = 3005 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 3006 desired_collector_type_ = desired_collector_type; 3007 } 3008 SignalHeapTrimDaemon(self); 3009} 3010 3011void Heap::RequestHeapTrim() { 3012 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 3013 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 3014 // a space it will hold its lock and can become a cause of jank. 3015 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 3016 // forking. 3017 3018 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 3019 // because that only marks object heads, so a large array looks like lots of empty space. We 3020 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 3021 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3022 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3023 // not how much use we're making of those pages. 3024 3025 Thread* self = Thread::Current(); 3026 Runtime* runtime = Runtime::Current(); 3027 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 3028 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3029 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3030 // as we don't hold the lock while requesting the trim). 3031 return; 3032 } 3033 { 3034 MutexLock mu(self, *heap_trim_request_lock_); 3035 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3036 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3037 // just yet. 3038 return; 3039 } 3040 heap_trim_request_pending_ = true; 3041 uint64_t current_time = NanoTime(); 3042 if (heap_transition_or_trim_target_time_ < current_time) { 3043 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 3044 } 3045 } 3046 // Notify the daemon thread which will actually do the heap trim. 3047 SignalHeapTrimDaemon(self); 3048} 3049 3050void Heap::SignalHeapTrimDaemon(Thread* self) { 3051 JNIEnv* env = self->GetJniEnv(); 3052 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3053 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3054 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3055 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3056 CHECK(!env->ExceptionCheck()); 3057} 3058 3059void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3060 if (rosalloc_space_ != nullptr) { 3061 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3062 } 3063 if (bump_pointer_space_ != nullptr) { 3064 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3065 } 3066} 3067 3068void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3069 if (rosalloc_space_ != nullptr) { 3070 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3071 } 3072} 3073 3074void Heap::RevokeAllThreadLocalBuffers() { 3075 if (rosalloc_space_ != nullptr) { 3076 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3077 } 3078 if (bump_pointer_space_ != nullptr) { 3079 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3080 } 3081} 3082 3083bool Heap::IsGCRequestPending() const { 3084 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3085} 3086 3087void Heap::RunFinalization(JNIEnv* env) { 3088 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3089 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3090 CHECK(WellKnownClasses::java_lang_System != nullptr); 3091 WellKnownClasses::java_lang_System_runFinalization = 3092 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3093 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3094 } 3095 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3096 WellKnownClasses::java_lang_System_runFinalization); 3097} 3098 3099void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 3100 Thread* self = ThreadForEnv(env); 3101 if (native_need_to_run_finalization_) { 3102 RunFinalization(env); 3103 UpdateMaxNativeFootprint(); 3104 native_need_to_run_finalization_ = false; 3105 } 3106 // Total number of native bytes allocated. 3107 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3108 new_native_bytes_allocated += bytes; 3109 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3110 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 3111 collector::kGcTypeFull; 3112 3113 // The second watermark is higher than the gc watermark. If you hit this it means you are 3114 // allocating native objects faster than the GC can keep up with. 3115 if (new_native_bytes_allocated > native_footprint_limit_) { 3116 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3117 // Just finished a GC, attempt to run finalizers. 3118 RunFinalization(env); 3119 CHECK(!env->ExceptionCheck()); 3120 } 3121 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3122 if (new_native_bytes_allocated > native_footprint_limit_) { 3123 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3124 RunFinalization(env); 3125 native_need_to_run_finalization_ = false; 3126 CHECK(!env->ExceptionCheck()); 3127 } 3128 // We have just run finalizers, update the native watermark since it is very likely that 3129 // finalizers released native managed allocations. 3130 UpdateMaxNativeFootprint(); 3131 } else if (!IsGCRequestPending()) { 3132 if (IsGcConcurrent()) { 3133 RequestConcurrentGC(self); 3134 } else { 3135 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3136 } 3137 } 3138 } 3139} 3140 3141void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 3142 int expected_size, new_size; 3143 do { 3144 expected_size = native_bytes_allocated_.LoadRelaxed(); 3145 new_size = expected_size - bytes; 3146 if (UNLIKELY(new_size < 0)) { 3147 ScopedObjectAccess soa(env); 3148 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3149 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 3150 "registered as allocated", bytes, expected_size).c_str()); 3151 break; 3152 } 3153 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, new_size)); 3154} 3155 3156size_t Heap::GetTotalMemory() const { 3157 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3158} 3159 3160void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3161 DCHECK(mod_union_table != nullptr); 3162 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3163} 3164 3165void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3166 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3167 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3168 CHECK_GE(byte_count, sizeof(mirror::Object)); 3169} 3170 3171void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3172 CHECK(remembered_set != nullptr); 3173 space::Space* space = remembered_set->GetSpace(); 3174 CHECK(space != nullptr); 3175 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3176 remembered_sets_.Put(space, remembered_set); 3177 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3178} 3179 3180void Heap::RemoveRememberedSet(space::Space* space) { 3181 CHECK(space != nullptr); 3182 auto it = remembered_sets_.find(space); 3183 CHECK(it != remembered_sets_.end()); 3184 delete it->second; 3185 remembered_sets_.erase(it); 3186 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3187} 3188 3189void Heap::ClearMarkedObjects() { 3190 // Clear all of the spaces' mark bitmaps. 3191 for (const auto& space : GetContinuousSpaces()) { 3192 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3193 if (space->GetLiveBitmap() != mark_bitmap) { 3194 mark_bitmap->Clear(); 3195 } 3196 } 3197 // Clear the marked objects in the discontinous space object sets. 3198 for (const auto& space : GetDiscontinuousSpaces()) { 3199 space->GetMarkBitmap()->Clear(); 3200 } 3201} 3202 3203} // namespace gc 3204} // namespace art 3205