heap.cc revision b225890e02bc8d5864217743eaef306d5387e0e9
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; 89static constexpr size_t kNonMovingSpaceCapacity = 64 * MB; 90// How many reserve entries are at the end of the allocation stack, these are only needed if the 91// allocation stack overflows. 92static constexpr size_t kAllocationStackReserveSize = 1024; 93// Default mark stack size in bytes. 94static const size_t kDefaultMarkStackSize = 64 * KB; 95// Define space name. 96static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 97static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 98static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 99static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 100 101Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 102 double target_utilization, double foreground_heap_growth_multiplier, size_t capacity, 103 const std::string& image_file_name, const InstructionSet image_instruction_set, 104 CollectorType foreground_collector_type, CollectorType background_collector_type, 105 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 106 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 107 bool ignore_max_footprint, bool use_tlab, 108 bool verify_pre_gc_heap, bool verify_pre_sweeping_heap, bool verify_post_gc_heap, 109 bool verify_pre_gc_rosalloc, bool verify_pre_sweeping_rosalloc, 110 bool verify_post_gc_rosalloc, bool use_homogeneous_space_compaction_for_oom, 111 uint64_t min_interval_homogeneous_space_compaction_by_oom) 112 : non_moving_space_(nullptr), 113 rosalloc_space_(nullptr), 114 dlmalloc_space_(nullptr), 115 main_space_(nullptr), 116 collector_type_(kCollectorTypeNone), 117 foreground_collector_type_(foreground_collector_type), 118 background_collector_type_(background_collector_type), 119 desired_collector_type_(foreground_collector_type_), 120 heap_trim_request_lock_(nullptr), 121 last_trim_time_(0), 122 heap_transition_or_trim_target_time_(0), 123 heap_trim_request_pending_(false), 124 parallel_gc_threads_(parallel_gc_threads), 125 conc_gc_threads_(conc_gc_threads), 126 low_memory_mode_(low_memory_mode), 127 long_pause_log_threshold_(long_pause_log_threshold), 128 long_gc_log_threshold_(long_gc_log_threshold), 129 ignore_max_footprint_(ignore_max_footprint), 130 zygote_creation_lock_("zygote creation lock", kZygoteCreationLock), 131 have_zygote_space_(false), 132 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 133 collector_type_running_(kCollectorTypeNone), 134 last_gc_type_(collector::kGcTypeNone), 135 next_gc_type_(collector::kGcTypePartial), 136 capacity_(capacity), 137 growth_limit_(growth_limit), 138 max_allowed_footprint_(initial_size), 139 native_footprint_gc_watermark_(initial_size), 140 native_footprint_limit_(2 * initial_size), 141 native_need_to_run_finalization_(false), 142 // Initially assume we perceive jank in case the process state is never updated. 143 process_state_(kProcessStateJankPerceptible), 144 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 145 total_bytes_freed_ever_(0), 146 total_objects_freed_ever_(0), 147 num_bytes_allocated_(0), 148 native_bytes_allocated_(0), 149 gc_memory_overhead_(0), 150 verify_missing_card_marks_(false), 151 verify_system_weaks_(false), 152 verify_pre_gc_heap_(verify_pre_gc_heap), 153 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 154 verify_post_gc_heap_(verify_post_gc_heap), 155 verify_mod_union_table_(false), 156 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 157 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 158 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 159 last_gc_time_ns_(NanoTime()), 160 allocation_rate_(0), 161 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 162 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 163 * verification is enabled, we limit the size of allocation stacks to speed up their 164 * searching. 165 */ 166 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 167 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 168 current_allocator_(kAllocatorTypeDlMalloc), 169 current_non_moving_allocator_(kAllocatorTypeNonMoving), 170 bump_pointer_space_(nullptr), 171 temp_space_(nullptr), 172 min_free_(min_free), 173 max_free_(max_free), 174 target_utilization_(target_utilization), 175 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 176 total_wait_time_(0), 177 total_allocation_time_(0), 178 verify_object_mode_(kVerifyObjectModeDisabled), 179 disable_moving_gc_count_(0), 180 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 181 use_tlab_(use_tlab), 182 main_space_backup_(nullptr), 183 min_interval_homogeneous_space_compaction_by_oom_( 184 min_interval_homogeneous_space_compaction_by_oom), 185 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 186 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 187 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 188 LOG(INFO) << "Heap() entering"; 189 } 190 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 191 // entrypoints. 192 if (!Runtime::Current()->IsZygote()) { 193 large_object_threshold_ = kDefaultLargeObjectThreshold; 194 // Background compaction is currently not supported for command line runs. 195 if (background_collector_type_ != foreground_collector_type_) { 196 VLOG(heap) << "Disabling background compaction for non zygote"; 197 background_collector_type_ = foreground_collector_type_; 198 } 199 } 200 ChangeCollector(desired_collector_type_); 201 live_bitmap_.reset(new accounting::HeapBitmap(this)); 202 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 203 // Requested begin for the alloc space, to follow the mapped image and oat files 204 byte* requested_alloc_space_begin = nullptr; 205 if (!image_file_name.empty()) { 206 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 207 image_instruction_set); 208 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 209 AddSpace(image_space); 210 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 211 // isn't going to get in the middle 212 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 213 CHECK_GT(oat_file_end_addr, image_space->End()); 214 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 215 } 216 /* 217 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 218 +- nonmoving space (kNonMovingSpaceCapacity) +- 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 220 +-main alloc space / bump space 1 (capacity_) +- 221 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 222 +-????????????????????????????????????????????+- 223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 224 +-main alloc space2 / bump space 2 (capacity_)+- 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 226 */ 227 bool support_homogeneous_space_compaction = 228 background_collector_type == gc::kCollectorTypeHomogeneousSpaceCompact || 229 use_homogeneous_space_compaction_for_oom; 230 // We may use the same space the main space for the non moving space if we don't need to compact 231 // from the main space. 232 // This is not the case if we support homogeneous compaction or have a moving background 233 // collector type. 234 const bool is_zygote = Runtime::Current()->IsZygote(); 235 bool separate_non_moving_space = is_zygote || 236 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 237 IsMovingGc(background_collector_type_); 238 if (foreground_collector_type == kCollectorTypeGSS) { 239 separate_non_moving_space = false; 240 } 241 std::unique_ptr<MemMap> main_mem_map_1; 242 std::unique_ptr<MemMap> main_mem_map_2; 243 byte* request_begin = requested_alloc_space_begin; 244 if (request_begin != nullptr && separate_non_moving_space) { 245 request_begin += kNonMovingSpaceCapacity; 246 } 247 std::string error_str; 248 std::unique_ptr<MemMap> non_moving_space_mem_map; 249 if (separate_non_moving_space) { 250 // Reserve the non moving mem map before the other two since it needs to be at a specific 251 // address. 252 non_moving_space_mem_map.reset( 253 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 254 kNonMovingSpaceCapacity, PROT_READ | PROT_WRITE, true, &error_str)); 255 CHECK(non_moving_space_mem_map != nullptr) << error_str; 256 } 257 // Attempt to create 2 mem maps at or after the requested begin. 258 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 259 PROT_READ | PROT_WRITE, &error_str)); 260 CHECK(main_mem_map_1.get() != nullptr) << error_str; 261 if (support_homogeneous_space_compaction || 262 background_collector_type_ == kCollectorTypeSS || 263 foreground_collector_type_ == kCollectorTypeSS) { 264 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 265 capacity_, PROT_READ | PROT_WRITE, 266 &error_str)); 267 CHECK(main_mem_map_2.get() != nullptr) << error_str; 268 } 269 // Create the non moving space first so that bitmaps don't take up the address range. 270 if (separate_non_moving_space) { 271 // Non moving space is always dlmalloc since we currently don't have support for multiple 272 // active rosalloc spaces. 273 const size_t size = non_moving_space_mem_map->Size(); 274 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 275 non_moving_space_mem_map.release(), "zygote / non moving space", initial_size, 276 initial_size, size, size, false); 277 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 278 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 279 << requested_alloc_space_begin; 280 AddSpace(non_moving_space_); 281 } 282 // Create other spaces based on whether or not we have a moving GC. 283 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 284 // Create bump pointer spaces. 285 // We only to create the bump pointer if the foreground collector is a compacting GC. 286 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 287 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 288 main_mem_map_1.release()); 289 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 290 AddSpace(bump_pointer_space_); 291 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 292 main_mem_map_2.release()); 293 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 294 AddSpace(temp_space_); 295 CHECK(separate_non_moving_space); 296 } else { 297 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 298 CHECK(main_space_ != nullptr); 299 AddSpace(main_space_); 300 if (!separate_non_moving_space) { 301 non_moving_space_ = main_space_; 302 CHECK(!non_moving_space_->CanMoveObjects()); 303 } 304 if (foreground_collector_type_ == kCollectorTypeGSS) { 305 CHECK_EQ(foreground_collector_type_, background_collector_type_); 306 // Create bump pointer spaces instead of a backup space. 307 main_mem_map_2.release(); 308 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 309 kGSSBumpPointerSpaceCapacity, nullptr); 310 CHECK(bump_pointer_space_ != nullptr); 311 AddSpace(bump_pointer_space_); 312 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 313 kGSSBumpPointerSpaceCapacity, nullptr); 314 CHECK(temp_space_ != nullptr); 315 AddSpace(temp_space_); 316 } else if (main_mem_map_2.get() != nullptr) { 317 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 318 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 319 growth_limit_, capacity_, name, true)); 320 CHECK(main_space_backup_.get() != nullptr); 321 // Add the space so its accounted for in the heap_begin and heap_end. 322 AddSpace(main_space_backup_.get()); 323 } 324 } 325 CHECK(non_moving_space_ != nullptr); 326 CHECK(!non_moving_space_->CanMoveObjects()); 327 // Allocate the large object space. 328 if (kUseFreeListSpaceForLOS) { 329 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity_); 330 } else { 331 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 332 } 333 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 334 AddSpace(large_object_space_); 335 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 336 CHECK(!continuous_spaces_.empty()); 337 // Relies on the spaces being sorted. 338 byte* heap_begin = continuous_spaces_.front()->Begin(); 339 byte* heap_end = continuous_spaces_.back()->Limit(); 340 size_t heap_capacity = heap_end - heap_begin; 341 // Remove the main backup space since it slows down the GC to have unused extra spaces. 342 if (main_space_backup_.get() != nullptr) { 343 RemoveSpace(main_space_backup_.get()); 344 } 345 // Allocate the card table. 346 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 347 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 348 // Card cache for now since it makes it easier for us to update the references to the copying 349 // spaces. 350 accounting::ModUnionTable* mod_union_table = 351 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 352 GetImageSpace()); 353 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 354 AddModUnionTable(mod_union_table); 355 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 356 accounting::RememberedSet* non_moving_space_rem_set = 357 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 358 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 359 AddRememberedSet(non_moving_space_rem_set); 360 } 361 // TODO: Count objects in the image space here? 362 num_bytes_allocated_.StoreRelaxed(0); 363 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 364 kDefaultMarkStackSize)); 365 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 366 allocation_stack_.reset(accounting::ObjectStack::Create( 367 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 368 live_stack_.reset(accounting::ObjectStack::Create( 369 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 370 // It's still too early to take a lock because there are no threads yet, but we can create locks 371 // now. We don't create it earlier to make it clear that you can't use locks during heap 372 // initialization. 373 gc_complete_lock_ = new Mutex("GC complete lock"); 374 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 375 *gc_complete_lock_)); 376 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 377 last_gc_size_ = GetBytesAllocated(); 378 if (ignore_max_footprint_) { 379 SetIdealFootprint(std::numeric_limits<size_t>::max()); 380 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 381 } 382 CHECK_NE(max_allowed_footprint_, 0U); 383 // Create our garbage collectors. 384 for (size_t i = 0; i < 2; ++i) { 385 const bool concurrent = i != 0; 386 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 387 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 388 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 389 } 390 if (kMovingCollector) { 391 // TODO: Clean this up. 392 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 393 semi_space_collector_ = new collector::SemiSpace(this, generational, 394 generational ? "generational" : ""); 395 garbage_collectors_.push_back(semi_space_collector_); 396 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 397 garbage_collectors_.push_back(concurrent_copying_collector_); 398 mark_compact_collector_ = new collector::MarkCompact(this); 399 garbage_collectors_.push_back(mark_compact_collector_); 400 } 401 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr) { 402 // Check that there's no gap between the image space and the non moving space so that the 403 // immune region won't break (eg. due to a large object allocated in the gap). 404 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 405 non_moving_space_->GetMemMap()); 406 if (!no_gap) { 407 MemMap::DumpMaps(LOG(ERROR)); 408 LOG(FATAL) << "There's a gap between the image space and the main space"; 409 } 410 } 411 if (running_on_valgrind_) { 412 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 413 } 414 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 415 LOG(INFO) << "Heap() exiting"; 416 } 417} 418 419MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 420 int prot_flags, std::string* out_error_str) { 421 while (true) { 422 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 423 PROT_READ | PROT_WRITE, true, out_error_str); 424 if (map != nullptr || request_begin == nullptr) { 425 return map; 426 } 427 // Retry a second time with no specified request begin. 428 request_begin = nullptr; 429 } 430 return nullptr; 431} 432 433space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 434 size_t growth_limit, size_t capacity, 435 const char* name, bool can_move_objects) { 436 space::MallocSpace* malloc_space = nullptr; 437 if (kUseRosAlloc) { 438 // Create rosalloc space. 439 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 440 initial_size, growth_limit, capacity, 441 low_memory_mode_, can_move_objects); 442 } else { 443 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 444 initial_size, growth_limit, capacity, 445 can_move_objects); 446 } 447 if (collector::SemiSpace::kUseRememberedSet) { 448 accounting::RememberedSet* rem_set = 449 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 450 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 451 AddRememberedSet(rem_set); 452 } 453 CHECK(malloc_space != nullptr) << "Failed to create " << name; 454 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 455 return malloc_space; 456} 457 458void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 459 size_t capacity) { 460 // Is background compaction is enabled? 461 bool can_move_objects = IsMovingGc(background_collector_type_) != 462 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 463 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 464 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 465 // from the main space to the zygote space. If background compaction is enabled, always pass in 466 // that we can move objets. 467 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 468 // After the zygote we want this to be false if we don't have background compaction enabled so 469 // that getting primitive array elements is faster. 470 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 471 can_move_objects = !have_zygote_space_ && foreground_collector_type_ != kCollectorTypeGSS; 472 } 473 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 474 RemoveRememberedSet(main_space_); 475 } 476 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 477 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 478 can_move_objects); 479 SetSpaceAsDefault(main_space_); 480 VLOG(heap) << "Created main space " << main_space_; 481} 482 483void Heap::ChangeAllocator(AllocatorType allocator) { 484 if (current_allocator_ != allocator) { 485 // These two allocators are only used internally and don't have any entrypoints. 486 CHECK_NE(allocator, kAllocatorTypeLOS); 487 CHECK_NE(allocator, kAllocatorTypeNonMoving); 488 current_allocator_ = allocator; 489 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 490 SetQuickAllocEntryPointsAllocator(current_allocator_); 491 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 492 } 493} 494 495void Heap::DisableCompaction() { 496 if (IsMovingGc(foreground_collector_type_)) { 497 foreground_collector_type_ = kCollectorTypeCMS; 498 } 499 if (IsMovingGc(background_collector_type_)) { 500 background_collector_type_ = foreground_collector_type_; 501 } 502 TransitionCollector(foreground_collector_type_); 503} 504 505std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 506 if (!IsValidContinuousSpaceObjectAddress(klass)) { 507 return StringPrintf("<non heap address klass %p>", klass); 508 } 509 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 510 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 511 std::string result("["); 512 result += SafeGetClassDescriptor(component_type); 513 return result; 514 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 515 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 516 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 517 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 518 } else { 519 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 520 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 521 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 522 } 523 const DexFile* dex_file = dex_cache->GetDexFile(); 524 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 525 if (class_def_idx == DexFile::kDexNoIndex16) { 526 return "<class def not found>"; 527 } 528 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 529 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 530 return dex_file->GetTypeDescriptor(type_id); 531 } 532} 533 534std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 535 if (obj == nullptr) { 536 return "null"; 537 } 538 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 539 if (klass == nullptr) { 540 return "(class=null)"; 541 } 542 std::string result(SafeGetClassDescriptor(klass)); 543 if (obj->IsClass()) { 544 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 545 } 546 return result; 547} 548 549void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 550 if (obj == nullptr) { 551 stream << "(obj=null)"; 552 return; 553 } 554 if (IsAligned<kObjectAlignment>(obj)) { 555 space::Space* space = nullptr; 556 // Don't use find space since it only finds spaces which actually contain objects instead of 557 // spaces which may contain objects (e.g. cleared bump pointer spaces). 558 for (const auto& cur_space : continuous_spaces_) { 559 if (cur_space->HasAddress(obj)) { 560 space = cur_space; 561 break; 562 } 563 } 564 // Unprotect all the spaces. 565 for (const auto& space : continuous_spaces_) { 566 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 567 } 568 stream << "Object " << obj; 569 if (space != nullptr) { 570 stream << " in space " << *space; 571 } 572 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 573 stream << "\nclass=" << klass; 574 if (klass != nullptr) { 575 stream << " type= " << SafePrettyTypeOf(obj); 576 } 577 // Re-protect the address we faulted on. 578 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 579 } 580} 581 582bool Heap::IsCompilingBoot() const { 583 for (const auto& space : continuous_spaces_) { 584 if (space->IsImageSpace() || space->IsZygoteSpace()) { 585 return false; 586 } 587 } 588 return true; 589} 590 591bool Heap::HasImageSpace() const { 592 for (const auto& space : continuous_spaces_) { 593 if (space->IsImageSpace()) { 594 return true; 595 } 596 } 597 return false; 598} 599 600void Heap::IncrementDisableMovingGC(Thread* self) { 601 // Need to do this holding the lock to prevent races where the GC is about to run / running when 602 // we attempt to disable it. 603 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 604 MutexLock mu(self, *gc_complete_lock_); 605 ++disable_moving_gc_count_; 606 if (IsMovingGc(collector_type_running_)) { 607 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 608 } 609} 610 611void Heap::DecrementDisableMovingGC(Thread* self) { 612 MutexLock mu(self, *gc_complete_lock_); 613 CHECK_GE(disable_moving_gc_count_, 0U); 614 --disable_moving_gc_count_; 615} 616 617void Heap::UpdateProcessState(ProcessState process_state) { 618 if (process_state_ != process_state) { 619 process_state_ = process_state; 620 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 621 // Start at index 1 to avoid "is always false" warning. 622 // Have iteration 1 always transition the collector. 623 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 624 ? foreground_collector_type_ : background_collector_type_); 625 usleep(kCollectorTransitionStressWait); 626 } 627 if (process_state_ == kProcessStateJankPerceptible) { 628 // Transition back to foreground right away to prevent jank. 629 RequestCollectorTransition(foreground_collector_type_, 0); 630 } else { 631 // Don't delay for debug builds since we may want to stress test the GC. 632 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 633 // special handling which does a homogenous space compaction once but then doesn't transition 634 // the collector. 635 RequestCollectorTransition(background_collector_type_, 636 kIsDebugBuild ? 0 : kCollectorTransitionWait); 637 } 638 } 639} 640 641void Heap::CreateThreadPool() { 642 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 643 if (num_threads != 0) { 644 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 645 } 646} 647 648void Heap::VisitObjects(ObjectCallback callback, void* arg) { 649 Thread* self = Thread::Current(); 650 // GCs can move objects, so don't allow this. 651 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 652 if (bump_pointer_space_ != nullptr) { 653 // Visit objects in bump pointer space. 654 bump_pointer_space_->Walk(callback, arg); 655 } 656 // TODO: Switch to standard begin and end to use ranged a based loop. 657 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 658 it < end; ++it) { 659 mirror::Object* obj = *it; 660 if (obj != nullptr && obj->GetClass() != nullptr) { 661 // Avoid the race condition caused by the object not yet being written into the allocation 662 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 663 // there can be nulls on the allocation stack. 664 callback(obj, arg); 665 } 666 } 667 GetLiveBitmap()->Walk(callback, arg); 668 self->EndAssertNoThreadSuspension(old_cause); 669} 670 671void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 672 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 673 space::ContinuousSpace* space2 = non_moving_space_; 674 // TODO: Generalize this to n bitmaps? 675 CHECK(space1 != nullptr); 676 CHECK(space2 != nullptr); 677 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 678 large_object_space_->GetLiveBitmap(), stack); 679} 680 681void Heap::DeleteThreadPool() { 682 thread_pool_.reset(nullptr); 683} 684 685void Heap::AddSpace(space::Space* space) { 686 CHECK(space != nullptr); 687 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 688 if (space->IsContinuousSpace()) { 689 DCHECK(!space->IsDiscontinuousSpace()); 690 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 691 // Continuous spaces don't necessarily have bitmaps. 692 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 693 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 694 if (live_bitmap != nullptr) { 695 CHECK(mark_bitmap != nullptr); 696 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 697 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 698 } 699 continuous_spaces_.push_back(continuous_space); 700 // Ensure that spaces remain sorted in increasing order of start address. 701 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 702 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 703 return a->Begin() < b->Begin(); 704 }); 705 } else { 706 CHECK(space->IsDiscontinuousSpace()); 707 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 708 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 709 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 710 discontinuous_spaces_.push_back(discontinuous_space); 711 } 712 if (space->IsAllocSpace()) { 713 alloc_spaces_.push_back(space->AsAllocSpace()); 714 } 715} 716 717void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 718 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 719 if (continuous_space->IsDlMallocSpace()) { 720 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 721 } else if (continuous_space->IsRosAllocSpace()) { 722 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 723 } 724} 725 726void Heap::RemoveSpace(space::Space* space) { 727 DCHECK(space != nullptr); 728 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 729 if (space->IsContinuousSpace()) { 730 DCHECK(!space->IsDiscontinuousSpace()); 731 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 732 // Continuous spaces don't necessarily have bitmaps. 733 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 734 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 735 if (live_bitmap != nullptr) { 736 DCHECK(mark_bitmap != nullptr); 737 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 738 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 739 } 740 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 741 DCHECK(it != continuous_spaces_.end()); 742 continuous_spaces_.erase(it); 743 } else { 744 DCHECK(space->IsDiscontinuousSpace()); 745 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 746 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 747 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 748 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 749 discontinuous_space); 750 DCHECK(it != discontinuous_spaces_.end()); 751 discontinuous_spaces_.erase(it); 752 } 753 if (space->IsAllocSpace()) { 754 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 755 DCHECK(it != alloc_spaces_.end()); 756 alloc_spaces_.erase(it); 757 } 758} 759 760void Heap::RegisterGCAllocation(size_t bytes) { 761 gc_memory_overhead_.FetchAndAddSequentiallyConsistent(bytes); 762} 763 764void Heap::RegisterGCDeAllocation(size_t bytes) { 765 gc_memory_overhead_.FetchAndSubSequentiallyConsistent(bytes); 766} 767 768void Heap::DumpGcPerformanceInfo(std::ostream& os) { 769 // Dump cumulative timings. 770 os << "Dumping cumulative Gc timings\n"; 771 uint64_t total_duration = 0; 772 // Dump cumulative loggers for each GC type. 773 uint64_t total_paused_time = 0; 774 for (auto& collector : garbage_collectors_) { 775 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 776 const size_t iterations = logger.GetIterations(); 777 const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram(); 778 if (iterations != 0 && pause_histogram.SampleSize() != 0) { 779 os << ConstDumpable<CumulativeLogger>(logger); 780 const uint64_t total_ns = logger.GetTotalNs(); 781 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 782 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 783 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 784 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 785 Histogram<uint64_t>::CumulativeData cumulative_data; 786 pause_histogram.CreateHistogram(&cumulative_data); 787 pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data); 788 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) 789 << " mean time: " << PrettyDuration(total_ns / iterations) << "\n" 790 << collector->GetName() << " freed: " << freed_objects 791 << " objects with total size " << PrettySize(freed_bytes) << "\n" 792 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 793 << PrettySize(freed_bytes / seconds) << "/s\n"; 794 total_duration += total_ns; 795 total_paused_time += total_pause_ns; 796 } 797 collector->ResetMeasurements(); 798 } 799 uint64_t allocation_time = 800 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 801 if (total_duration != 0) { 802 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 803 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 804 os << "Mean GC size throughput: " 805 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 806 os << "Mean GC object throughput: " 807 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 808 } 809 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 810 os << "Total number of allocations " << total_objects_allocated << "\n"; 811 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 812 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 813 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 814 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 815 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 816 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 817 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 818 if (kMeasureAllocationTime) { 819 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 820 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 821 << "\n"; 822 } 823 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 824 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 825 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_.LoadRelaxed(); 826 BaseMutex::DumpAll(os); 827} 828 829Heap::~Heap() { 830 VLOG(heap) << "Starting ~Heap()"; 831 STLDeleteElements(&garbage_collectors_); 832 // If we don't reset then the mark stack complains in its destructor. 833 allocation_stack_->Reset(); 834 live_stack_->Reset(); 835 STLDeleteValues(&mod_union_tables_); 836 STLDeleteValues(&remembered_sets_); 837 STLDeleteElements(&continuous_spaces_); 838 STLDeleteElements(&discontinuous_spaces_); 839 delete gc_complete_lock_; 840 delete heap_trim_request_lock_; 841 VLOG(heap) << "Finished ~Heap()"; 842} 843 844space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 845 bool fail_ok) const { 846 for (const auto& space : continuous_spaces_) { 847 if (space->Contains(obj)) { 848 return space; 849 } 850 } 851 if (!fail_ok) { 852 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 853 } 854 return NULL; 855} 856 857space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 858 bool fail_ok) const { 859 for (const auto& space : discontinuous_spaces_) { 860 if (space->Contains(obj)) { 861 return space; 862 } 863 } 864 if (!fail_ok) { 865 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 866 } 867 return NULL; 868} 869 870space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 871 space::Space* result = FindContinuousSpaceFromObject(obj, true); 872 if (result != NULL) { 873 return result; 874 } 875 return FindDiscontinuousSpaceFromObject(obj, true); 876} 877 878space::ImageSpace* Heap::GetImageSpace() const { 879 for (const auto& space : continuous_spaces_) { 880 if (space->IsImageSpace()) { 881 return space->AsImageSpace(); 882 } 883 } 884 return NULL; 885} 886 887void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 888 std::ostringstream oss; 889 size_t total_bytes_free = GetFreeMemory(); 890 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 891 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 892 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 893 if (total_bytes_free >= byte_count) { 894 space::AllocSpace* space = nullptr; 895 if (allocator_type == kAllocatorTypeNonMoving) { 896 space = non_moving_space_; 897 } else if (allocator_type == kAllocatorTypeRosAlloc || 898 allocator_type == kAllocatorTypeDlMalloc) { 899 space = main_space_; 900 } else if (allocator_type == kAllocatorTypeBumpPointer || 901 allocator_type == kAllocatorTypeTLAB) { 902 space = bump_pointer_space_; 903 } 904 if (space != nullptr) { 905 space->LogFragmentationAllocFailure(oss, byte_count); 906 } 907 } 908 self->ThrowOutOfMemoryError(oss.str().c_str()); 909} 910 911void Heap::DoPendingTransitionOrTrim() { 912 Thread* self = Thread::Current(); 913 CollectorType desired_collector_type; 914 // Wait until we reach the desired transition time. 915 while (true) { 916 uint64_t wait_time; 917 { 918 MutexLock mu(self, *heap_trim_request_lock_); 919 desired_collector_type = desired_collector_type_; 920 uint64_t current_time = NanoTime(); 921 if (current_time >= heap_transition_or_trim_target_time_) { 922 break; 923 } 924 wait_time = heap_transition_or_trim_target_time_ - current_time; 925 } 926 ScopedThreadStateChange tsc(self, kSleeping); 927 usleep(wait_time / 1000); // Usleep takes microseconds. 928 } 929 // Launch homogeneous space compaction if it is desired. 930 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 931 if (!CareAboutPauseTimes()) { 932 PerformHomogeneousSpaceCompact(); 933 } 934 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 935 desired_collector_type = collector_type_; 936 return; 937 } 938 // Transition the collector if the desired collector type is not the same as the current 939 // collector type. 940 TransitionCollector(desired_collector_type); 941 if (!CareAboutPauseTimes()) { 942 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 943 // about pauses. 944 Runtime* runtime = Runtime::Current(); 945 runtime->GetThreadList()->SuspendAll(); 946 uint64_t start_time = NanoTime(); 947 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 948 VLOG(heap) << "Deflating " << count << " monitors took " 949 << PrettyDuration(NanoTime() - start_time); 950 runtime->GetThreadList()->ResumeAll(); 951 } 952 // Do a heap trim if it is needed. 953 Trim(); 954} 955 956void Heap::Trim() { 957 Thread* self = Thread::Current(); 958 { 959 MutexLock mu(self, *heap_trim_request_lock_); 960 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 961 return; 962 } 963 last_trim_time_ = NanoTime(); 964 heap_trim_request_pending_ = false; 965 } 966 { 967 // Need to do this before acquiring the locks since we don't want to get suspended while 968 // holding any locks. 969 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 970 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 971 // trimming. 972 MutexLock mu(self, *gc_complete_lock_); 973 // Ensure there is only one GC at a time. 974 WaitForGcToCompleteLocked(kGcCauseTrim, self); 975 collector_type_running_ = kCollectorTypeHeapTrim; 976 } 977 uint64_t start_ns = NanoTime(); 978 // Trim the managed spaces. 979 uint64_t total_alloc_space_allocated = 0; 980 uint64_t total_alloc_space_size = 0; 981 uint64_t managed_reclaimed = 0; 982 for (const auto& space : continuous_spaces_) { 983 if (space->IsMallocSpace()) { 984 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 985 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 986 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 987 // for a long period of time. 988 managed_reclaimed += malloc_space->Trim(); 989 } 990 total_alloc_space_size += malloc_space->Size(); 991 } 992 } 993 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated(); 994 if (bump_pointer_space_ != nullptr) { 995 total_alloc_space_allocated -= bump_pointer_space_->Size(); 996 } 997 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 998 static_cast<float>(total_alloc_space_size); 999 uint64_t gc_heap_end_ns = NanoTime(); 1000 // We never move things in the native heap, so we can finish the GC at this point. 1001 FinishGC(self, collector::kGcTypeNone); 1002 size_t native_reclaimed = 0; 1003 // Only trim the native heap if we don't care about pauses. 1004 if (!CareAboutPauseTimes()) { 1005#if defined(USE_DLMALLOC) 1006 // Trim the native heap. 1007 dlmalloc_trim(0); 1008 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1009#elif defined(USE_JEMALLOC) 1010 // Jemalloc does it's own internal trimming. 1011#else 1012 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1013#endif 1014 } 1015 uint64_t end_ns = NanoTime(); 1016 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1017 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1018 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1019 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1020 << "%."; 1021} 1022 1023bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1024 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1025 // taking the lock. 1026 if (obj == nullptr) { 1027 return true; 1028 } 1029 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1030} 1031 1032bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1033 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1034} 1035 1036bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1037 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1038 return false; 1039 } 1040 for (const auto& space : continuous_spaces_) { 1041 if (space->HasAddress(obj)) { 1042 return true; 1043 } 1044 } 1045 return false; 1046} 1047 1048bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1049 bool search_live_stack, bool sorted) { 1050 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1051 return false; 1052 } 1053 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1054 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1055 if (obj == klass) { 1056 // This case happens for java.lang.Class. 1057 return true; 1058 } 1059 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1060 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1061 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1062 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1063 return temp_space_->Contains(obj); 1064 } 1065 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1066 space::DiscontinuousSpace* d_space = nullptr; 1067 if (c_space != nullptr) { 1068 if (c_space->GetLiveBitmap()->Test(obj)) { 1069 return true; 1070 } 1071 } else { 1072 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1073 if (d_space != nullptr) { 1074 if (d_space->GetLiveBitmap()->Test(obj)) { 1075 return true; 1076 } 1077 } 1078 } 1079 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1080 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1081 if (i > 0) { 1082 NanoSleep(MsToNs(10)); 1083 } 1084 if (search_allocation_stack) { 1085 if (sorted) { 1086 if (allocation_stack_->ContainsSorted(obj)) { 1087 return true; 1088 } 1089 } else if (allocation_stack_->Contains(obj)) { 1090 return true; 1091 } 1092 } 1093 1094 if (search_live_stack) { 1095 if (sorted) { 1096 if (live_stack_->ContainsSorted(obj)) { 1097 return true; 1098 } 1099 } else if (live_stack_->Contains(obj)) { 1100 return true; 1101 } 1102 } 1103 } 1104 // We need to check the bitmaps again since there is a race where we mark something as live and 1105 // then clear the stack containing it. 1106 if (c_space != nullptr) { 1107 if (c_space->GetLiveBitmap()->Test(obj)) { 1108 return true; 1109 } 1110 } else { 1111 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1112 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1113 return true; 1114 } 1115 } 1116 return false; 1117} 1118 1119std::string Heap::DumpSpaces() const { 1120 std::ostringstream oss; 1121 DumpSpaces(oss); 1122 return oss.str(); 1123} 1124 1125void Heap::DumpSpaces(std::ostream& stream) const { 1126 for (const auto& space : continuous_spaces_) { 1127 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1128 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1129 stream << space << " " << *space << "\n"; 1130 if (live_bitmap != nullptr) { 1131 stream << live_bitmap << " " << *live_bitmap << "\n"; 1132 } 1133 if (mark_bitmap != nullptr) { 1134 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1135 } 1136 } 1137 for (const auto& space : discontinuous_spaces_) { 1138 stream << space << " " << *space << "\n"; 1139 } 1140} 1141 1142void Heap::VerifyObjectBody(mirror::Object* obj) { 1143 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1144 return; 1145 } 1146 1147 // Ignore early dawn of the universe verifications. 1148 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1149 return; 1150 } 1151 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1152 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1153 CHECK(c != nullptr) << "Null class in object " << obj; 1154 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1155 CHECK(VerifyClassClass(c)); 1156 1157 if (verify_object_mode_ > kVerifyObjectModeFast) { 1158 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1159 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1160 } 1161} 1162 1163void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1164 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1165} 1166 1167void Heap::VerifyHeap() { 1168 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1169 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1170} 1171 1172void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1173 // Use signed comparison since freed bytes can be negative when background compaction foreground 1174 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1175 // free list backed space typically increasing memory footprint due to padding and binning. 1176 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1177 // Note: This relies on 2s complement for handling negative freed_bytes. 1178 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1179 if (Runtime::Current()->HasStatsEnabled()) { 1180 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1181 thread_stats->freed_objects += freed_objects; 1182 thread_stats->freed_bytes += freed_bytes; 1183 // TODO: Do this concurrently. 1184 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1185 global_stats->freed_objects += freed_objects; 1186 global_stats->freed_bytes += freed_bytes; 1187 } 1188} 1189 1190space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1191 for (const auto& space : continuous_spaces_) { 1192 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1193 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1194 return space->AsContinuousSpace()->AsRosAllocSpace(); 1195 } 1196 } 1197 } 1198 return nullptr; 1199} 1200 1201mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1202 size_t alloc_size, size_t* bytes_allocated, 1203 size_t* usable_size, 1204 mirror::Class** klass) { 1205 bool was_default_allocator = allocator == GetCurrentAllocator(); 1206 DCHECK(klass != nullptr); 1207 StackHandleScope<1> hs(self); 1208 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1209 klass = nullptr; // Invalidate for safety. 1210 // The allocation failed. If the GC is running, block until it completes, and then retry the 1211 // allocation. 1212 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1213 if (last_gc != collector::kGcTypeNone) { 1214 // If we were the default allocator but the allocator changed while we were suspended, 1215 // abort the allocation. 1216 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1217 return nullptr; 1218 } 1219 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1220 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1221 usable_size); 1222 if (ptr != nullptr) { 1223 return ptr; 1224 } 1225 } 1226 1227 collector::GcType tried_type = next_gc_type_; 1228 const bool gc_ran = 1229 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1230 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1231 return nullptr; 1232 } 1233 if (gc_ran) { 1234 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1235 usable_size); 1236 if (ptr != nullptr) { 1237 return ptr; 1238 } 1239 } 1240 1241 // Loop through our different Gc types and try to Gc until we get enough free memory. 1242 for (collector::GcType gc_type : gc_plan_) { 1243 if (gc_type == tried_type) { 1244 continue; 1245 } 1246 // Attempt to run the collector, if we succeed, re-try the allocation. 1247 const bool gc_ran = 1248 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1249 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1250 return nullptr; 1251 } 1252 if (gc_ran) { 1253 // Did we free sufficient memory for the allocation to succeed? 1254 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1255 usable_size); 1256 if (ptr != nullptr) { 1257 return ptr; 1258 } 1259 } 1260 } 1261 // Allocations have failed after GCs; this is an exceptional state. 1262 // Try harder, growing the heap if necessary. 1263 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1264 usable_size); 1265 if (ptr != nullptr) { 1266 return ptr; 1267 } 1268 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1269 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1270 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1271 // OOME. 1272 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1273 << " allocation"; 1274 // TODO: Run finalization, but this may cause more allocations to occur. 1275 // We don't need a WaitForGcToComplete here either. 1276 DCHECK(!gc_plan_.empty()); 1277 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1278 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1279 return nullptr; 1280 } 1281 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1282 if (ptr == nullptr && use_homogeneous_space_compaction_for_oom_) { 1283 const uint64_t current_time = NanoTime(); 1284 if ((allocator == kAllocatorTypeRosAlloc || allocator == kAllocatorTypeDlMalloc) && 1285 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1286 min_interval_homogeneous_space_compaction_by_oom_) { 1287 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1288 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1289 switch (result) { 1290 case HomogeneousSpaceCompactResult::kSuccess: 1291 // If the allocation succeeded, we delayed an oom. 1292 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1293 if (ptr != nullptr) { 1294 count_delayed_oom_++; 1295 } 1296 break; 1297 case HomogeneousSpaceCompactResult::kErrorReject: 1298 // Reject due to disabled moving GC. 1299 break; 1300 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1301 // Throw OOM by default. 1302 break; 1303 default: { 1304 LOG(FATAL) << "Unimplemented homogeneous space compaction result " << static_cast<size_t>(result); 1305 } 1306 } 1307 // Always print that we ran homogeneous space compation since this can cause jank. 1308 VLOG(heap) << "Ran heap homogeneous space compaction, " 1309 << " requested defragmentation " 1310 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1311 << " performed defragmentation " 1312 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1313 << " ignored homogeneous space compaction " 1314 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1315 << " delayed count = " 1316 << count_delayed_oom_.LoadSequentiallyConsistent(); 1317 } 1318 } 1319 // If the allocation hasn't succeeded by this point, throw an OOM error. 1320 if (ptr == nullptr) { 1321 ThrowOutOfMemoryError(self, alloc_size, allocator); 1322 } 1323 return ptr; 1324} 1325 1326void Heap::SetTargetHeapUtilization(float target) { 1327 DCHECK_GT(target, 0.0f); // asserted in Java code 1328 DCHECK_LT(target, 1.0f); 1329 target_utilization_ = target; 1330} 1331 1332size_t Heap::GetObjectsAllocated() const { 1333 size_t total = 0; 1334 for (space::AllocSpace* space : alloc_spaces_) { 1335 total += space->GetObjectsAllocated(); 1336 } 1337 return total; 1338} 1339 1340uint64_t Heap::GetObjectsAllocatedEver() const { 1341 return GetObjectsFreedEver() + GetObjectsAllocated(); 1342} 1343 1344uint64_t Heap::GetBytesAllocatedEver() const { 1345 return GetBytesFreedEver() + GetBytesAllocated(); 1346} 1347 1348class InstanceCounter { 1349 public: 1350 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1351 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1352 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1353 } 1354 static void Callback(mirror::Object* obj, void* arg) 1355 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1356 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1357 mirror::Class* instance_class = obj->GetClass(); 1358 CHECK(instance_class != nullptr); 1359 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1360 if (instance_counter->use_is_assignable_from_) { 1361 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1362 ++instance_counter->counts_[i]; 1363 } 1364 } else if (instance_class == instance_counter->classes_[i]) { 1365 ++instance_counter->counts_[i]; 1366 } 1367 } 1368 } 1369 1370 private: 1371 const std::vector<mirror::Class*>& classes_; 1372 bool use_is_assignable_from_; 1373 uint64_t* const counts_; 1374 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1375}; 1376 1377void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1378 uint64_t* counts) { 1379 // Can't do any GC in this function since this may move classes. 1380 Thread* self = Thread::Current(); 1381 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1382 InstanceCounter counter(classes, use_is_assignable_from, counts); 1383 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1384 VisitObjects(InstanceCounter::Callback, &counter); 1385 self->EndAssertNoThreadSuspension(old_cause); 1386} 1387 1388class InstanceCollector { 1389 public: 1390 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1391 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1392 : class_(c), max_count_(max_count), instances_(instances) { 1393 } 1394 static void Callback(mirror::Object* obj, void* arg) 1395 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1396 DCHECK(arg != nullptr); 1397 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1398 mirror::Class* instance_class = obj->GetClass(); 1399 if (instance_class == instance_collector->class_) { 1400 if (instance_collector->max_count_ == 0 || 1401 instance_collector->instances_.size() < instance_collector->max_count_) { 1402 instance_collector->instances_.push_back(obj); 1403 } 1404 } 1405 } 1406 1407 private: 1408 mirror::Class* class_; 1409 uint32_t max_count_; 1410 std::vector<mirror::Object*>& instances_; 1411 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1412}; 1413 1414void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1415 std::vector<mirror::Object*>& instances) { 1416 // Can't do any GC in this function since this may move classes. 1417 Thread* self = Thread::Current(); 1418 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1419 InstanceCollector collector(c, max_count, instances); 1420 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1421 VisitObjects(&InstanceCollector::Callback, &collector); 1422 self->EndAssertNoThreadSuspension(old_cause); 1423} 1424 1425class ReferringObjectsFinder { 1426 public: 1427 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1428 std::vector<mirror::Object*>& referring_objects) 1429 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1430 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1431 } 1432 1433 static void Callback(mirror::Object* obj, void* arg) 1434 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1435 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1436 } 1437 1438 // For bitmap Visit. 1439 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1440 // annotalysis on visitors. 1441 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1442 o->VisitReferences<true>(*this, VoidFunctor()); 1443 } 1444 1445 // For Object::VisitReferences. 1446 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1447 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1448 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1449 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1450 referring_objects_.push_back(obj); 1451 } 1452 } 1453 1454 private: 1455 mirror::Object* object_; 1456 uint32_t max_count_; 1457 std::vector<mirror::Object*>& referring_objects_; 1458 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1459}; 1460 1461void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1462 std::vector<mirror::Object*>& referring_objects) { 1463 // Can't do any GC in this function since this may move the object o. 1464 Thread* self = Thread::Current(); 1465 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1466 ReferringObjectsFinder finder(o, max_count, referring_objects); 1467 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1468 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1469 self->EndAssertNoThreadSuspension(old_cause); 1470} 1471 1472void Heap::CollectGarbage(bool clear_soft_references) { 1473 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1474 // last GC will not have necessarily been cleared. 1475 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1476} 1477 1478HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1479 Thread* self = Thread::Current(); 1480 // Inc requested homogeneous space compaction. 1481 count_requested_homogeneous_space_compaction_++; 1482 // Store performed homogeneous space compaction at a new request arrival. 1483 ThreadList* tl = Runtime::Current()->GetThreadList(); 1484 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1485 Locks::mutator_lock_->AssertNotHeld(self); 1486 { 1487 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1488 MutexLock mu(self, *gc_complete_lock_); 1489 // Ensure there is only one GC at a time. 1490 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1491 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1492 // is non zero. 1493 // If the collecotr type changed to something which doesn't benefit from homogeneous space compaction, 1494 // exit. 1495 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_)) { 1496 return HomogeneousSpaceCompactResult::kErrorReject; 1497 } 1498 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1499 } 1500 if (Runtime::Current()->IsShuttingDown(self)) { 1501 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1502 // cause objects to get finalized. 1503 FinishGC(self, collector::kGcTypeNone); 1504 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1505 } 1506 // Suspend all threads. 1507 tl->SuspendAll(); 1508 uint64_t start_time = NanoTime(); 1509 // Launch compaction. 1510 space::MallocSpace* to_space = main_space_backup_.release(); 1511 space::MallocSpace* from_space = main_space_; 1512 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1513 const uint64_t space_size_before_compaction = from_space->Size(); 1514 AddSpace(to_space); 1515 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1516 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1517 from_space->GetMemMap()->Protect(PROT_READ); 1518 const uint64_t space_size_after_compaction = to_space->Size(); 1519 main_space_ = to_space; 1520 main_space_backup_.reset(from_space); 1521 RemoveSpace(from_space); 1522 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1523 // Update performed homogeneous space compaction count. 1524 count_performed_homogeneous_space_compaction_++; 1525 // Print statics log and resume all threads. 1526 uint64_t duration = NanoTime() - start_time; 1527 LOG(INFO) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1528 << PrettySize(space_size_before_compaction) << " -> " 1529 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1530 << std::fixed << static_cast<double>(space_size_after_compaction) / 1531 static_cast<double>(space_size_before_compaction); 1532 tl->ResumeAll(); 1533 // Finish GC. 1534 reference_processor_.EnqueueClearedReferences(self); 1535 GrowForUtilization(semi_space_collector_); 1536 FinishGC(self, collector::kGcTypeFull); 1537 return HomogeneousSpaceCompactResult::kSuccess; 1538} 1539 1540 1541void Heap::TransitionCollector(CollectorType collector_type) { 1542 if (collector_type == collector_type_) { 1543 return; 1544 } 1545 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1546 << " -> " << static_cast<int>(collector_type); 1547 uint64_t start_time = NanoTime(); 1548 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1549 Runtime* const runtime = Runtime::Current(); 1550 ThreadList* const tl = runtime->GetThreadList(); 1551 Thread* const self = Thread::Current(); 1552 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1553 Locks::mutator_lock_->AssertNotHeld(self); 1554 const bool copying_transition = 1555 IsMovingGc(background_collector_type_) || IsMovingGc(foreground_collector_type_); 1556 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1557 // compacting_gc_disable_count_, this should rarely occurs). 1558 for (;;) { 1559 { 1560 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1561 MutexLock mu(self, *gc_complete_lock_); 1562 // Ensure there is only one GC at a time. 1563 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1564 // If someone else beat us to it and changed the collector before we could, exit. 1565 // This is safe to do before the suspend all since we set the collector_type_running_ before 1566 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1567 // then it would get blocked on WaitForGcToCompleteLocked. 1568 if (collector_type == collector_type_) { 1569 return; 1570 } 1571 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1572 if (!copying_transition || disable_moving_gc_count_ == 0) { 1573 // TODO: Not hard code in semi-space collector? 1574 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1575 break; 1576 } 1577 } 1578 usleep(1000); 1579 } 1580 if (runtime->IsShuttingDown(self)) { 1581 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1582 // cause objects to get finalized. 1583 FinishGC(self, collector::kGcTypeNone); 1584 return; 1585 } 1586 tl->SuspendAll(); 1587 switch (collector_type) { 1588 case kCollectorTypeSS: { 1589 if (!IsMovingGc(collector_type_)) { 1590 // Create the bump pointer space from the backup space. 1591 CHECK(main_space_backup_ != nullptr); 1592 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1593 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1594 // pointer space last transition it will be protected. 1595 CHECK(mem_map != nullptr); 1596 mem_map->Protect(PROT_READ | PROT_WRITE); 1597 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1598 mem_map.release()); 1599 AddSpace(bump_pointer_space_); 1600 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1601 // Use the now empty main space mem map for the bump pointer temp space. 1602 mem_map.reset(main_space_->ReleaseMemMap()); 1603 // Unset the pointers just in case. 1604 if (dlmalloc_space_ == main_space_) { 1605 dlmalloc_space_ = nullptr; 1606 } else if (rosalloc_space_ == main_space_) { 1607 rosalloc_space_ = nullptr; 1608 } 1609 // Remove the main space so that we don't try to trim it, this doens't work for debug 1610 // builds since RosAlloc attempts to read the magic number from a protected page. 1611 RemoveSpace(main_space_); 1612 RemoveRememberedSet(main_space_); 1613 delete main_space_; // Delete the space since it has been removed. 1614 main_space_ = nullptr; 1615 RemoveRememberedSet(main_space_backup_.get()); 1616 main_space_backup_.reset(nullptr); // Deletes the space. 1617 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1618 mem_map.release()); 1619 AddSpace(temp_space_); 1620 } 1621 break; 1622 } 1623 case kCollectorTypeMS: 1624 // Fall through. 1625 case kCollectorTypeCMS: { 1626 if (IsMovingGc(collector_type_)) { 1627 CHECK(temp_space_ != nullptr); 1628 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1629 RemoveSpace(temp_space_); 1630 temp_space_ = nullptr; 1631 mem_map->Protect(PROT_READ | PROT_WRITE); 1632 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1633 mem_map->Size()); 1634 mem_map.release(); 1635 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1636 AddSpace(main_space_); 1637 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1638 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1639 RemoveSpace(bump_pointer_space_); 1640 bump_pointer_space_ = nullptr; 1641 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1642 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1643 if (kIsDebugBuild && kUseRosAlloc) { 1644 mem_map->Protect(PROT_READ | PROT_WRITE); 1645 } 1646 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1647 mem_map->Size(), mem_map->Size(), 1648 name, true)); 1649 if (kIsDebugBuild && kUseRosAlloc) { 1650 mem_map->Protect(PROT_NONE); 1651 } 1652 mem_map.release(); 1653 } 1654 break; 1655 } 1656 default: { 1657 LOG(FATAL) << "Attempted to transition to invalid collector type " 1658 << static_cast<size_t>(collector_type); 1659 break; 1660 } 1661 } 1662 ChangeCollector(collector_type); 1663 tl->ResumeAll(); 1664 // Can't call into java code with all threads suspended. 1665 reference_processor_.EnqueueClearedReferences(self); 1666 uint64_t duration = NanoTime() - start_time; 1667 GrowForUtilization(semi_space_collector_); 1668 FinishGC(self, collector::kGcTypeFull); 1669 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1670 int32_t delta_allocated = before_allocated - after_allocated; 1671 std::string saved_str; 1672 if (delta_allocated >= 0) { 1673 saved_str = " saved at least " + PrettySize(delta_allocated); 1674 } else { 1675 saved_str = " expanded " + PrettySize(-delta_allocated); 1676 } 1677 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1678 << PrettyDuration(duration) << saved_str; 1679} 1680 1681void Heap::ChangeCollector(CollectorType collector_type) { 1682 // TODO: Only do this with all mutators suspended to avoid races. 1683 if (collector_type != collector_type_) { 1684 if (collector_type == kCollectorTypeMC) { 1685 // Don't allow mark compact unless support is compiled in. 1686 CHECK(kMarkCompactSupport); 1687 } 1688 collector_type_ = collector_type; 1689 gc_plan_.clear(); 1690 switch (collector_type_) { 1691 case kCollectorTypeCC: // Fall-through. 1692 case kCollectorTypeMC: // Fall-through. 1693 case kCollectorTypeSS: // Fall-through. 1694 case kCollectorTypeGSS: { 1695 gc_plan_.push_back(collector::kGcTypeFull); 1696 if (use_tlab_) { 1697 ChangeAllocator(kAllocatorTypeTLAB); 1698 } else { 1699 ChangeAllocator(kAllocatorTypeBumpPointer); 1700 } 1701 break; 1702 } 1703 case kCollectorTypeMS: { 1704 gc_plan_.push_back(collector::kGcTypeSticky); 1705 gc_plan_.push_back(collector::kGcTypePartial); 1706 gc_plan_.push_back(collector::kGcTypeFull); 1707 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1708 break; 1709 } 1710 case kCollectorTypeCMS: { 1711 gc_plan_.push_back(collector::kGcTypeSticky); 1712 gc_plan_.push_back(collector::kGcTypePartial); 1713 gc_plan_.push_back(collector::kGcTypeFull); 1714 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1715 break; 1716 } 1717 default: { 1718 LOG(FATAL) << "Unimplemented"; 1719 } 1720 } 1721 if (IsGcConcurrent()) { 1722 concurrent_start_bytes_ = 1723 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1724 } else { 1725 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1726 } 1727 } 1728} 1729 1730// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1731class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1732 public: 1733 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1734 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1735 } 1736 1737 void BuildBins(space::ContinuousSpace* space) { 1738 bin_live_bitmap_ = space->GetLiveBitmap(); 1739 bin_mark_bitmap_ = space->GetMarkBitmap(); 1740 BinContext context; 1741 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1742 context.collector_ = this; 1743 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1744 // Note: This requires traversing the space in increasing order of object addresses. 1745 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1746 // Add the last bin which spans after the last object to the end of the space. 1747 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1748 } 1749 1750 private: 1751 struct BinContext { 1752 uintptr_t prev_; // The end of the previous object. 1753 ZygoteCompactingCollector* collector_; 1754 }; 1755 // Maps from bin sizes to locations. 1756 std::multimap<size_t, uintptr_t> bins_; 1757 // Live bitmap of the space which contains the bins. 1758 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1759 // Mark bitmap of the space which contains the bins. 1760 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1761 1762 static void Callback(mirror::Object* obj, void* arg) 1763 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1764 DCHECK(arg != nullptr); 1765 BinContext* context = reinterpret_cast<BinContext*>(arg); 1766 ZygoteCompactingCollector* collector = context->collector_; 1767 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1768 size_t bin_size = object_addr - context->prev_; 1769 // Add the bin consisting of the end of the previous object to the start of the current object. 1770 collector->AddBin(bin_size, context->prev_); 1771 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1772 } 1773 1774 void AddBin(size_t size, uintptr_t position) { 1775 if (size != 0) { 1776 bins_.insert(std::make_pair(size, position)); 1777 } 1778 } 1779 1780 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1781 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1782 // allocator. 1783 return false; 1784 } 1785 1786 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1787 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1788 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1789 mirror::Object* forward_address; 1790 // Find the smallest bin which we can move obj in. 1791 auto it = bins_.lower_bound(object_size); 1792 if (it == bins_.end()) { 1793 // No available space in the bins, place it in the target space instead (grows the zygote 1794 // space). 1795 size_t bytes_allocated; 1796 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1797 if (to_space_live_bitmap_ != nullptr) { 1798 to_space_live_bitmap_->Set(forward_address); 1799 } else { 1800 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1801 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1802 } 1803 } else { 1804 size_t size = it->first; 1805 uintptr_t pos = it->second; 1806 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1807 forward_address = reinterpret_cast<mirror::Object*>(pos); 1808 // Set the live and mark bits so that sweeping system weaks works properly. 1809 bin_live_bitmap_->Set(forward_address); 1810 bin_mark_bitmap_->Set(forward_address); 1811 DCHECK_GE(size, object_size); 1812 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1813 } 1814 // Copy the object over to its new location. 1815 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1816 if (kUseBakerOrBrooksReadBarrier) { 1817 obj->AssertReadBarrierPointer(); 1818 if (kUseBrooksReadBarrier) { 1819 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1820 forward_address->SetReadBarrierPointer(forward_address); 1821 } 1822 forward_address->AssertReadBarrierPointer(); 1823 } 1824 return forward_address; 1825 } 1826}; 1827 1828void Heap::UnBindBitmaps() { 1829 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1830 for (const auto& space : GetContinuousSpaces()) { 1831 if (space->IsContinuousMemMapAllocSpace()) { 1832 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1833 if (alloc_space->HasBoundBitmaps()) { 1834 alloc_space->UnBindBitmaps(); 1835 } 1836 } 1837 } 1838} 1839 1840void Heap::PreZygoteFork() { 1841 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1842 Thread* self = Thread::Current(); 1843 MutexLock mu(self, zygote_creation_lock_); 1844 // Try to see if we have any Zygote spaces. 1845 if (have_zygote_space_) { 1846 return; 1847 } 1848 VLOG(heap) << "Starting PreZygoteFork"; 1849 // Trim the pages at the end of the non moving space. 1850 non_moving_space_->Trim(); 1851 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1852 // there. 1853 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1854 // Change the collector to the post zygote one. 1855 bool same_space = non_moving_space_ == main_space_; 1856 if (kCompactZygote) { 1857 DCHECK(semi_space_collector_ != nullptr); 1858 // Temporarily disable rosalloc verification because the zygote 1859 // compaction will mess up the rosalloc internal metadata. 1860 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1861 ZygoteCompactingCollector zygote_collector(this); 1862 zygote_collector.BuildBins(non_moving_space_); 1863 // Create a new bump pointer space which we will compact into. 1864 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1865 non_moving_space_->Limit()); 1866 // Compact the bump pointer space to a new zygote bump pointer space. 1867 bool reset_main_space = false; 1868 if (IsMovingGc(collector_type_)) { 1869 zygote_collector.SetFromSpace(bump_pointer_space_); 1870 } else { 1871 CHECK(main_space_ != nullptr); 1872 // Copy from the main space. 1873 zygote_collector.SetFromSpace(main_space_); 1874 reset_main_space = true; 1875 } 1876 zygote_collector.SetToSpace(&target_space); 1877 zygote_collector.SetSwapSemiSpaces(false); 1878 zygote_collector.Run(kGcCauseCollectorTransition, false); 1879 if (reset_main_space) { 1880 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1881 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1882 MemMap* mem_map = main_space_->ReleaseMemMap(); 1883 RemoveSpace(main_space_); 1884 space::Space* old_main_space = main_space_; 1885 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1886 delete old_main_space; 1887 AddSpace(main_space_); 1888 } else { 1889 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1890 } 1891 if (temp_space_ != nullptr) { 1892 CHECK(temp_space_->IsEmpty()); 1893 } 1894 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1895 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1896 // Update the end and write out image. 1897 non_moving_space_->SetEnd(target_space.End()); 1898 non_moving_space_->SetLimit(target_space.Limit()); 1899 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1900 } 1901 ChangeCollector(foreground_collector_type_); 1902 // Save the old space so that we can remove it after we complete creating the zygote space. 1903 space::MallocSpace* old_alloc_space = non_moving_space_; 1904 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1905 // the remaining available space. 1906 // Remove the old space before creating the zygote space since creating the zygote space sets 1907 // the old alloc space's bitmaps to nullptr. 1908 RemoveSpace(old_alloc_space); 1909 if (collector::SemiSpace::kUseRememberedSet) { 1910 // Sanity bound check. 1911 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1912 // Remove the remembered set for the now zygote space (the old 1913 // non-moving space). Note now that we have compacted objects into 1914 // the zygote space, the data in the remembered set is no longer 1915 // needed. The zygote space will instead have a mod-union table 1916 // from this point on. 1917 RemoveRememberedSet(old_alloc_space); 1918 } 1919 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1920 low_memory_mode_, 1921 &non_moving_space_); 1922 CHECK(!non_moving_space_->CanMoveObjects()); 1923 if (same_space) { 1924 main_space_ = non_moving_space_; 1925 SetSpaceAsDefault(main_space_); 1926 } 1927 delete old_alloc_space; 1928 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1929 AddSpace(zygote_space); 1930 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1931 AddSpace(non_moving_space_); 1932 have_zygote_space_ = true; 1933 // Enable large object space allocations. 1934 large_object_threshold_ = kDefaultLargeObjectThreshold; 1935 // Create the zygote space mod union table. 1936 accounting::ModUnionTable* mod_union_table = 1937 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1938 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1939 AddModUnionTable(mod_union_table); 1940 if (collector::SemiSpace::kUseRememberedSet) { 1941 // Add a new remembered set for the post-zygote non-moving space. 1942 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1943 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1944 non_moving_space_); 1945 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1946 << "Failed to create post-zygote non-moving space remembered set"; 1947 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1948 } 1949} 1950 1951void Heap::FlushAllocStack() { 1952 MarkAllocStackAsLive(allocation_stack_.get()); 1953 allocation_stack_->Reset(); 1954} 1955 1956void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 1957 accounting::ContinuousSpaceBitmap* bitmap2, 1958 accounting::LargeObjectBitmap* large_objects, 1959 accounting::ObjectStack* stack) { 1960 DCHECK(bitmap1 != nullptr); 1961 DCHECK(bitmap2 != nullptr); 1962 mirror::Object** limit = stack->End(); 1963 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1964 const mirror::Object* obj = *it; 1965 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1966 if (bitmap1->HasAddress(obj)) { 1967 bitmap1->Set(obj); 1968 } else if (bitmap2->HasAddress(obj)) { 1969 bitmap2->Set(obj); 1970 } else { 1971 large_objects->Set(obj); 1972 } 1973 } 1974 } 1975} 1976 1977void Heap::SwapSemiSpaces() { 1978 CHECK(bump_pointer_space_ != nullptr); 1979 CHECK(temp_space_ != nullptr); 1980 std::swap(bump_pointer_space_, temp_space_); 1981} 1982 1983void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1984 space::ContinuousMemMapAllocSpace* source_space, 1985 GcCause gc_cause) { 1986 CHECK(kMovingCollector); 1987 if (target_space != source_space) { 1988 // Don't swap spaces since this isn't a typical semi space collection. 1989 semi_space_collector_->SetSwapSemiSpaces(false); 1990 semi_space_collector_->SetFromSpace(source_space); 1991 semi_space_collector_->SetToSpace(target_space); 1992 semi_space_collector_->Run(gc_cause, false); 1993 } else { 1994 CHECK(target_space->IsBumpPointerSpace()) 1995 << "In-place compaction is only supported for bump pointer spaces"; 1996 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 1997 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 1998 } 1999} 2000 2001collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2002 bool clear_soft_references) { 2003 Thread* self = Thread::Current(); 2004 Runtime* runtime = Runtime::Current(); 2005 // If the heap can't run the GC, silently fail and return that no GC was run. 2006 switch (gc_type) { 2007 case collector::kGcTypePartial: { 2008 if (!have_zygote_space_) { 2009 return collector::kGcTypeNone; 2010 } 2011 break; 2012 } 2013 default: { 2014 // Other GC types don't have any special cases which makes them not runnable. The main case 2015 // here is full GC. 2016 } 2017 } 2018 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2019 Locks::mutator_lock_->AssertNotHeld(self); 2020 if (self->IsHandlingStackOverflow()) { 2021 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2022 } 2023 bool compacting_gc; 2024 { 2025 gc_complete_lock_->AssertNotHeld(self); 2026 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2027 MutexLock mu(self, *gc_complete_lock_); 2028 // Ensure there is only one GC at a time. 2029 WaitForGcToCompleteLocked(gc_cause, self); 2030 compacting_gc = IsMovingGc(collector_type_); 2031 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2032 if (compacting_gc && disable_moving_gc_count_ != 0) { 2033 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2034 return collector::kGcTypeNone; 2035 } 2036 collector_type_running_ = collector_type_; 2037 } 2038 2039 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2040 ++runtime->GetStats()->gc_for_alloc_count; 2041 ++self->GetStats()->gc_for_alloc_count; 2042 } 2043 uint64_t gc_start_time_ns = NanoTime(); 2044 uint64_t gc_start_size = GetBytesAllocated(); 2045 // Approximate allocation rate in bytes / second. 2046 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2047 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2048 if (LIKELY(ms_delta != 0)) { 2049 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2050 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2051 } 2052 2053 DCHECK_LT(gc_type, collector::kGcTypeMax); 2054 DCHECK_NE(gc_type, collector::kGcTypeNone); 2055 2056 collector::GarbageCollector* collector = nullptr; 2057 // TODO: Clean this up. 2058 if (compacting_gc) { 2059 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2060 current_allocator_ == kAllocatorTypeTLAB); 2061 switch (collector_type_) { 2062 case kCollectorTypeSS: 2063 // Fall-through. 2064 case kCollectorTypeGSS: 2065 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2066 semi_space_collector_->SetToSpace(temp_space_); 2067 semi_space_collector_->SetSwapSemiSpaces(true); 2068 collector = semi_space_collector_; 2069 break; 2070 case kCollectorTypeCC: 2071 collector = concurrent_copying_collector_; 2072 break; 2073 case kCollectorTypeMC: 2074 mark_compact_collector_->SetSpace(bump_pointer_space_); 2075 collector = mark_compact_collector_; 2076 break; 2077 default: 2078 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2079 } 2080 if (collector != mark_compact_collector_) { 2081 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2082 CHECK(temp_space_->IsEmpty()); 2083 } 2084 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2085 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2086 current_allocator_ == kAllocatorTypeDlMalloc) { 2087 collector = FindCollectorByGcType(gc_type); 2088 } else { 2089 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2090 } 2091 CHECK(collector != nullptr) 2092 << "Could not find garbage collector with collector_type=" 2093 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2094 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2095 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2096 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2097 RequestHeapTrim(); 2098 // Enqueue cleared references. 2099 reference_processor_.EnqueueClearedReferences(self); 2100 // Grow the heap so that we know when to perform the next GC. 2101 GrowForUtilization(collector); 2102 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2103 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2104 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2105 // (mutator time blocked >= long_pause_log_threshold_). 2106 bool log_gc = gc_cause == kGcCauseExplicit; 2107 if (!log_gc && CareAboutPauseTimes()) { 2108 // GC for alloc pauses the allocating thread, so consider it as a pause. 2109 log_gc = duration > long_gc_log_threshold_ || 2110 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2111 for (uint64_t pause : pause_times) { 2112 log_gc = log_gc || pause >= long_pause_log_threshold_; 2113 } 2114 } 2115 if (log_gc) { 2116 const size_t percent_free = GetPercentFree(); 2117 const size_t current_heap_size = GetBytesAllocated(); 2118 const size_t total_memory = GetTotalMemory(); 2119 std::ostringstream pause_string; 2120 for (size_t i = 0; i < pause_times.size(); ++i) { 2121 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2122 << ((i != pause_times.size() - 1) ? "," : ""); 2123 } 2124 LOG(INFO) << gc_cause << " " << collector->GetName() 2125 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2126 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2127 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2128 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2129 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2130 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2131 << " total " << PrettyDuration((duration / 1000) * 1000); 2132 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2133 } 2134 FinishGC(self, gc_type); 2135 // Inform DDMS that a GC completed. 2136 Dbg::GcDidFinish(); 2137 return gc_type; 2138} 2139 2140void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2141 MutexLock mu(self, *gc_complete_lock_); 2142 collector_type_running_ = kCollectorTypeNone; 2143 if (gc_type != collector::kGcTypeNone) { 2144 last_gc_type_ = gc_type; 2145 } 2146 // Wake anyone who may have been waiting for the GC to complete. 2147 gc_complete_cond_->Broadcast(self); 2148} 2149 2150static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2151 RootType /*root_type*/) { 2152 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2153 if (*root == obj) { 2154 LOG(INFO) << "Object " << obj << " is a root"; 2155 } 2156} 2157 2158class ScanVisitor { 2159 public: 2160 void operator()(const mirror::Object* obj) const { 2161 LOG(ERROR) << "Would have rescanned object " << obj; 2162 } 2163}; 2164 2165// Verify a reference from an object. 2166class VerifyReferenceVisitor { 2167 public: 2168 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2169 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2170 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2171 2172 size_t GetFailureCount() const { 2173 return fail_count_->LoadSequentiallyConsistent(); 2174 } 2175 2176 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2177 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2178 if (verify_referent_) { 2179 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2180 } 2181 } 2182 2183 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2184 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2185 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2186 } 2187 2188 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2189 return heap_->IsLiveObjectLocked(obj, true, false, true); 2190 } 2191 2192 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2193 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2194 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2195 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2196 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2197 << " thread_id= " << thread_id << " root_type= " << root_type; 2198 } 2199 } 2200 2201 private: 2202 // TODO: Fix the no thread safety analysis. 2203 // Returns false on failure. 2204 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2205 NO_THREAD_SAFETY_ANALYSIS { 2206 if (ref == nullptr || IsLive(ref)) { 2207 // Verify that the reference is live. 2208 return true; 2209 } 2210 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2211 // Print message on only on first failure to prevent spam. 2212 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2213 } 2214 if (obj != nullptr) { 2215 // Only do this part for non roots. 2216 accounting::CardTable* card_table = heap_->GetCardTable(); 2217 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2218 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2219 byte* card_addr = card_table->CardFromAddr(obj); 2220 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2221 << offset << "\n card value = " << static_cast<int>(*card_addr); 2222 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2223 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2224 } else { 2225 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2226 } 2227 2228 // Attempt to find the class inside of the recently freed objects. 2229 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2230 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2231 space::MallocSpace* space = ref_space->AsMallocSpace(); 2232 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2233 if (ref_class != nullptr) { 2234 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2235 << PrettyClass(ref_class); 2236 } else { 2237 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2238 } 2239 } 2240 2241 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2242 ref->GetClass()->IsClass()) { 2243 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2244 } else { 2245 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2246 << ") is not a valid heap address"; 2247 } 2248 2249 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2250 void* cover_begin = card_table->AddrFromCard(card_addr); 2251 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2252 accounting::CardTable::kCardSize); 2253 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2254 << "-" << cover_end; 2255 accounting::ContinuousSpaceBitmap* bitmap = 2256 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2257 2258 if (bitmap == nullptr) { 2259 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2260 if (!VerifyClassClass(obj->GetClass())) { 2261 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2262 } 2263 } else { 2264 // Print out how the object is live. 2265 if (bitmap->Test(obj)) { 2266 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2267 } 2268 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2269 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2270 } 2271 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2272 LOG(ERROR) << "Object " << obj << " found in live stack"; 2273 } 2274 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2275 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2276 } 2277 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2278 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2279 } 2280 // Attempt to see if the card table missed the reference. 2281 ScanVisitor scan_visitor; 2282 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2283 card_table->Scan(bitmap, byte_cover_begin, 2284 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2285 } 2286 2287 // Search to see if any of the roots reference our object. 2288 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2289 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2290 2291 // Search to see if any of the roots reference our reference. 2292 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2293 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2294 } 2295 return false; 2296 } 2297 2298 Heap* const heap_; 2299 Atomic<size_t>* const fail_count_; 2300 const bool verify_referent_; 2301}; 2302 2303// Verify all references within an object, for use with HeapBitmap::Visit. 2304class VerifyObjectVisitor { 2305 public: 2306 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2307 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2308 } 2309 2310 void operator()(mirror::Object* obj) const 2311 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2312 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2313 // be live or else how did we find it in the live bitmap? 2314 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2315 // The class doesn't count as a reference but we should verify it anyways. 2316 obj->VisitReferences<true>(visitor, visitor); 2317 } 2318 2319 static void VisitCallback(mirror::Object* obj, void* arg) 2320 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2321 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2322 visitor->operator()(obj); 2323 } 2324 2325 size_t GetFailureCount() const { 2326 return fail_count_->LoadSequentiallyConsistent(); 2327 } 2328 2329 private: 2330 Heap* const heap_; 2331 Atomic<size_t>* const fail_count_; 2332 const bool verify_referent_; 2333}; 2334 2335void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2336 // Slow path, the allocation stack push back must have already failed. 2337 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2338 do { 2339 // TODO: Add handle VerifyObject. 2340 StackHandleScope<1> hs(self); 2341 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2342 // Push our object into the reserve region of the allocaiton stack. This is only required due 2343 // to heap verification requiring that roots are live (either in the live bitmap or in the 2344 // allocation stack). 2345 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2346 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2347 } while (!allocation_stack_->AtomicPushBack(*obj)); 2348} 2349 2350void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2351 // Slow path, the allocation stack push back must have already failed. 2352 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2353 mirror::Object** start_address; 2354 mirror::Object** end_address; 2355 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2356 &end_address)) { 2357 // TODO: Add handle VerifyObject. 2358 StackHandleScope<1> hs(self); 2359 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2360 // Push our object into the reserve region of the allocaiton stack. This is only required due 2361 // to heap verification requiring that roots are live (either in the live bitmap or in the 2362 // allocation stack). 2363 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2364 // Push into the reserve allocation stack. 2365 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2366 } 2367 self->SetThreadLocalAllocationStack(start_address, end_address); 2368 // Retry on the new thread-local allocation stack. 2369 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2370} 2371 2372// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2373size_t Heap::VerifyHeapReferences(bool verify_referents) { 2374 Thread* self = Thread::Current(); 2375 Locks::mutator_lock_->AssertExclusiveHeld(self); 2376 // Lets sort our allocation stacks so that we can efficiently binary search them. 2377 allocation_stack_->Sort(); 2378 live_stack_->Sort(); 2379 // Since we sorted the allocation stack content, need to revoke all 2380 // thread-local allocation stacks. 2381 RevokeAllThreadLocalAllocationStacks(self); 2382 Atomic<size_t> fail_count_(0); 2383 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2384 // Verify objects in the allocation stack since these will be objects which were: 2385 // 1. Allocated prior to the GC (pre GC verification). 2386 // 2. Allocated during the GC (pre sweep GC verification). 2387 // We don't want to verify the objects in the live stack since they themselves may be 2388 // pointing to dead objects if they are not reachable. 2389 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2390 // Verify the roots: 2391 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2392 if (visitor.GetFailureCount() > 0) { 2393 // Dump mod-union tables. 2394 for (const auto& table_pair : mod_union_tables_) { 2395 accounting::ModUnionTable* mod_union_table = table_pair.second; 2396 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2397 } 2398 // Dump remembered sets. 2399 for (const auto& table_pair : remembered_sets_) { 2400 accounting::RememberedSet* remembered_set = table_pair.second; 2401 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2402 } 2403 DumpSpaces(LOG(ERROR)); 2404 } 2405 return visitor.GetFailureCount(); 2406} 2407 2408class VerifyReferenceCardVisitor { 2409 public: 2410 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2411 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2412 Locks::heap_bitmap_lock_) 2413 : heap_(heap), failed_(failed) { 2414 } 2415 2416 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2417 // annotalysis on visitors. 2418 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2419 NO_THREAD_SAFETY_ANALYSIS { 2420 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2421 // Filter out class references since changing an object's class does not mark the card as dirty. 2422 // Also handles large objects, since the only reference they hold is a class reference. 2423 if (ref != nullptr && !ref->IsClass()) { 2424 accounting::CardTable* card_table = heap_->GetCardTable(); 2425 // If the object is not dirty and it is referencing something in the live stack other than 2426 // class, then it must be on a dirty card. 2427 if (!card_table->AddrIsInCardTable(obj)) { 2428 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2429 *failed_ = true; 2430 } else if (!card_table->IsDirty(obj)) { 2431 // TODO: Check mod-union tables. 2432 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2433 // kCardDirty - 1 if it didnt get touched since we aged it. 2434 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2435 if (live_stack->ContainsSorted(ref)) { 2436 if (live_stack->ContainsSorted(obj)) { 2437 LOG(ERROR) << "Object " << obj << " found in live stack"; 2438 } 2439 if (heap_->GetLiveBitmap()->Test(obj)) { 2440 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2441 } 2442 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2443 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2444 2445 // Print which field of the object is dead. 2446 if (!obj->IsObjectArray()) { 2447 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2448 CHECK(klass != NULL); 2449 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2450 : klass->GetIFields(); 2451 CHECK(fields != NULL); 2452 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2453 mirror::ArtField* cur = fields->Get(i); 2454 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2455 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2456 << PrettyField(cur); 2457 break; 2458 } 2459 } 2460 } else { 2461 mirror::ObjectArray<mirror::Object>* object_array = 2462 obj->AsObjectArray<mirror::Object>(); 2463 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2464 if (object_array->Get(i) == ref) { 2465 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2466 } 2467 } 2468 } 2469 2470 *failed_ = true; 2471 } 2472 } 2473 } 2474 } 2475 2476 private: 2477 Heap* const heap_; 2478 bool* const failed_; 2479}; 2480 2481class VerifyLiveStackReferences { 2482 public: 2483 explicit VerifyLiveStackReferences(Heap* heap) 2484 : heap_(heap), 2485 failed_(false) {} 2486 2487 void operator()(mirror::Object* obj) const 2488 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2489 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2490 obj->VisitReferences<true>(visitor, VoidFunctor()); 2491 } 2492 2493 bool Failed() const { 2494 return failed_; 2495 } 2496 2497 private: 2498 Heap* const heap_; 2499 bool failed_; 2500}; 2501 2502bool Heap::VerifyMissingCardMarks() { 2503 Thread* self = Thread::Current(); 2504 Locks::mutator_lock_->AssertExclusiveHeld(self); 2505 2506 // We need to sort the live stack since we binary search it. 2507 live_stack_->Sort(); 2508 // Since we sorted the allocation stack content, need to revoke all 2509 // thread-local allocation stacks. 2510 RevokeAllThreadLocalAllocationStacks(self); 2511 VerifyLiveStackReferences visitor(this); 2512 GetLiveBitmap()->Visit(visitor); 2513 2514 // We can verify objects in the live stack since none of these should reference dead objects. 2515 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2516 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2517 visitor(*it); 2518 } 2519 } 2520 return !visitor.Failed(); 2521} 2522 2523void Heap::SwapStacks(Thread* self) { 2524 if (kUseThreadLocalAllocationStack) { 2525 live_stack_->AssertAllZero(); 2526 } 2527 allocation_stack_.swap(live_stack_); 2528} 2529 2530void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2531 // This must be called only during the pause. 2532 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2533 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2534 MutexLock mu2(self, *Locks::thread_list_lock_); 2535 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2536 for (Thread* t : thread_list) { 2537 t->RevokeThreadLocalAllocationStack(); 2538 } 2539} 2540 2541void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2542 if (kIsDebugBuild) { 2543 if (bump_pointer_space_ != nullptr) { 2544 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2545 } 2546 } 2547} 2548 2549accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2550 auto it = mod_union_tables_.find(space); 2551 if (it == mod_union_tables_.end()) { 2552 return nullptr; 2553 } 2554 return it->second; 2555} 2556 2557accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2558 auto it = remembered_sets_.find(space); 2559 if (it == remembered_sets_.end()) { 2560 return nullptr; 2561 } 2562 return it->second; 2563} 2564 2565void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2566 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2567 // Clear cards and keep track of cards cleared in the mod-union table. 2568 for (const auto& space : continuous_spaces_) { 2569 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2570 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2571 if (table != nullptr) { 2572 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2573 "ImageModUnionClearCards"; 2574 TimingLogger::ScopedTiming t(name, timings); 2575 table->ClearCards(); 2576 } else if (use_rem_sets && rem_set != nullptr) { 2577 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2578 << static_cast<int>(collector_type_); 2579 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2580 rem_set->ClearCards(); 2581 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2582 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2583 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2584 // were dirty before the GC started. 2585 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2586 // -> clean(cleaning thread). 2587 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2588 // roots and then we scan / update mod union tables after. We will always scan either card. 2589 // If we end up with the non aged card, we scan it it in the pause. 2590 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2591 VoidFunctor()); 2592 } 2593 } 2594} 2595 2596static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2597} 2598 2599void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2600 Thread* const self = Thread::Current(); 2601 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2602 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2603 if (verify_pre_gc_heap_) { 2604 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2605 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2606 size_t failures = VerifyHeapReferences(); 2607 if (failures > 0) { 2608 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2609 << " failures"; 2610 } 2611 } 2612 // Check that all objects which reference things in the live stack are on dirty cards. 2613 if (verify_missing_card_marks_) { 2614 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2615 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2616 SwapStacks(self); 2617 // Sort the live stack so that we can quickly binary search it later. 2618 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2619 << " missing card mark verification failed\n" << DumpSpaces(); 2620 SwapStacks(self); 2621 } 2622 if (verify_mod_union_table_) { 2623 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2624 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2625 for (const auto& table_pair : mod_union_tables_) { 2626 accounting::ModUnionTable* mod_union_table = table_pair.second; 2627 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2628 mod_union_table->Verify(); 2629 } 2630 } 2631} 2632 2633void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2634 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2635 collector::GarbageCollector::ScopedPause pause(gc); 2636 PreGcVerificationPaused(gc); 2637 } 2638} 2639 2640void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2641 // TODO: Add a new runtime option for this? 2642 if (verify_pre_gc_rosalloc_) { 2643 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2644 } 2645} 2646 2647void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2648 Thread* const self = Thread::Current(); 2649 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2650 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2651 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2652 // reachable objects. 2653 if (verify_pre_sweeping_heap_) { 2654 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2655 CHECK_NE(self->GetState(), kRunnable); 2656 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2657 // Swapping bound bitmaps does nothing. 2658 gc->SwapBitmaps(); 2659 // Pass in false since concurrent reference processing can mean that the reference referents 2660 // may point to dead objects at the point which PreSweepingGcVerification is called. 2661 size_t failures = VerifyHeapReferences(false); 2662 if (failures > 0) { 2663 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2664 << " failures"; 2665 } 2666 gc->SwapBitmaps(); 2667 } 2668 if (verify_pre_sweeping_rosalloc_) { 2669 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2670 } 2671} 2672 2673void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2674 // Only pause if we have to do some verification. 2675 Thread* const self = Thread::Current(); 2676 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2677 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2678 if (verify_system_weaks_) { 2679 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2680 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2681 mark_sweep->VerifySystemWeaks(); 2682 } 2683 if (verify_post_gc_rosalloc_) { 2684 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2685 } 2686 if (verify_post_gc_heap_) { 2687 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2688 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2689 size_t failures = VerifyHeapReferences(); 2690 if (failures > 0) { 2691 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2692 << " failures"; 2693 } 2694 } 2695} 2696 2697void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2698 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2699 collector::GarbageCollector::ScopedPause pause(gc); 2700 PreGcVerificationPaused(gc); 2701 } 2702} 2703 2704void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2705 TimingLogger::ScopedTiming t(name, timings); 2706 for (const auto& space : continuous_spaces_) { 2707 if (space->IsRosAllocSpace()) { 2708 VLOG(heap) << name << " : " << space->GetName(); 2709 space->AsRosAllocSpace()->Verify(); 2710 } 2711 } 2712} 2713 2714collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2715 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2716 MutexLock mu(self, *gc_complete_lock_); 2717 return WaitForGcToCompleteLocked(cause, self); 2718} 2719 2720collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2721 collector::GcType last_gc_type = collector::kGcTypeNone; 2722 uint64_t wait_start = NanoTime(); 2723 while (collector_type_running_ != kCollectorTypeNone) { 2724 ATRACE_BEGIN("GC: Wait For Completion"); 2725 // We must wait, change thread state then sleep on gc_complete_cond_; 2726 gc_complete_cond_->Wait(self); 2727 last_gc_type = last_gc_type_; 2728 ATRACE_END(); 2729 } 2730 uint64_t wait_time = NanoTime() - wait_start; 2731 total_wait_time_ += wait_time; 2732 if (wait_time > long_pause_log_threshold_) { 2733 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2734 << " for cause " << cause; 2735 } 2736 return last_gc_type; 2737} 2738 2739void Heap::DumpForSigQuit(std::ostream& os) { 2740 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2741 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2742 DumpGcPerformanceInfo(os); 2743} 2744 2745size_t Heap::GetPercentFree() { 2746 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2747} 2748 2749void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2750 if (max_allowed_footprint > GetMaxMemory()) { 2751 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2752 << PrettySize(GetMaxMemory()); 2753 max_allowed_footprint = GetMaxMemory(); 2754 } 2755 max_allowed_footprint_ = max_allowed_footprint; 2756} 2757 2758bool Heap::IsMovableObject(const mirror::Object* obj) const { 2759 if (kMovingCollector) { 2760 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2761 if (space != nullptr) { 2762 // TODO: Check large object? 2763 return space->CanMoveObjects(); 2764 } 2765 } 2766 return false; 2767} 2768 2769void Heap::UpdateMaxNativeFootprint() { 2770 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2771 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2772 size_t target_size = native_size / GetTargetHeapUtilization(); 2773 if (target_size > native_size + max_free_) { 2774 target_size = native_size + max_free_; 2775 } else if (target_size < native_size + min_free_) { 2776 target_size = native_size + min_free_; 2777 } 2778 native_footprint_gc_watermark_ = target_size; 2779 native_footprint_limit_ = 2 * target_size - native_size; 2780} 2781 2782collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2783 for (const auto& collector : garbage_collectors_) { 2784 if (collector->GetCollectorType() == collector_type_ && 2785 collector->GetGcType() == gc_type) { 2786 return collector; 2787 } 2788 } 2789 return nullptr; 2790} 2791 2792double Heap::HeapGrowthMultiplier() const { 2793 // If we don't care about pause times we are background, so return 1.0. 2794 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2795 return 1.0; 2796 } 2797 return foreground_heap_growth_multiplier_; 2798} 2799 2800void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2801 // We know what our utilization is at this moment. 2802 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2803 const uint64_t bytes_allocated = GetBytesAllocated(); 2804 last_gc_size_ = bytes_allocated; 2805 last_gc_time_ns_ = NanoTime(); 2806 uint64_t target_size; 2807 collector::GcType gc_type = collector_ran->GetGcType(); 2808 if (gc_type != collector::kGcTypeSticky) { 2809 // Grow the heap for non sticky GC. 2810 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2811 // foreground. 2812 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2813 CHECK_GE(delta, 0); 2814 target_size = bytes_allocated + delta * multiplier; 2815 target_size = std::min(target_size, 2816 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2817 target_size = std::max(target_size, 2818 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2819 native_need_to_run_finalization_ = true; 2820 next_gc_type_ = collector::kGcTypeSticky; 2821 } else { 2822 collector::GcType non_sticky_gc_type = 2823 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2824 // Find what the next non sticky collector will be. 2825 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2826 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2827 // do another sticky collection next. 2828 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2829 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2830 // if the sticky GC throughput always remained >= the full/partial throughput. 2831 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2832 non_sticky_collector->GetEstimatedMeanThroughput() && 2833 non_sticky_collector->NumberOfIterations() > 0 && 2834 bytes_allocated <= max_allowed_footprint_) { 2835 next_gc_type_ = collector::kGcTypeSticky; 2836 } else { 2837 next_gc_type_ = non_sticky_gc_type; 2838 } 2839 // If we have freed enough memory, shrink the heap back down. 2840 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2841 target_size = bytes_allocated + max_free_; 2842 } else { 2843 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2844 } 2845 } 2846 if (!ignore_max_footprint_) { 2847 SetIdealFootprint(target_size); 2848 if (IsGcConcurrent()) { 2849 // Calculate when to perform the next ConcurrentGC. 2850 // Calculate the estimated GC duration. 2851 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2852 // Estimate how many remaining bytes we will have when we need to start the next GC. 2853 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2854 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2855 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2856 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2857 // A never going to happen situation that from the estimated allocation rate we will exceed 2858 // the applications entire footprint with the given estimated allocation rate. Schedule 2859 // another GC nearly straight away. 2860 remaining_bytes = kMinConcurrentRemainingBytes; 2861 } 2862 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2863 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2864 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2865 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2866 // right away. 2867 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2868 static_cast<size_t>(bytes_allocated)); 2869 } 2870 } 2871} 2872 2873void Heap::ClearGrowthLimit() { 2874 growth_limit_ = capacity_; 2875 non_moving_space_->ClearGrowthLimit(); 2876} 2877 2878void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2879 ScopedObjectAccess soa(self); 2880 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2881 jvalue args[1]; 2882 args[0].l = arg.get(); 2883 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2884 // Restore object in case it gets moved. 2885 *object = soa.Decode<mirror::Object*>(arg.get()); 2886} 2887 2888void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2889 StackHandleScope<1> hs(self); 2890 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2891 RequestConcurrentGC(self); 2892} 2893 2894void Heap::RequestConcurrentGC(Thread* self) { 2895 // Make sure that we can do a concurrent GC. 2896 Runtime* runtime = Runtime::Current(); 2897 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2898 self->IsHandlingStackOverflow()) { 2899 return; 2900 } 2901 // We already have a request pending, no reason to start more until we update 2902 // concurrent_start_bytes_. 2903 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2904 JNIEnv* env = self->GetJniEnv(); 2905 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2906 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2907 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2908 WellKnownClasses::java_lang_Daemons_requestGC); 2909 CHECK(!env->ExceptionCheck()); 2910} 2911 2912void Heap::ConcurrentGC(Thread* self) { 2913 if (Runtime::Current()->IsShuttingDown(self)) { 2914 return; 2915 } 2916 // Wait for any GCs currently running to finish. 2917 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2918 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2919 // instead. E.g. can't do partial, so do full instead. 2920 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2921 collector::kGcTypeNone) { 2922 for (collector::GcType gc_type : gc_plan_) { 2923 // Attempt to run the collector, if we succeed, we are done. 2924 if (gc_type > next_gc_type_ && 2925 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2926 break; 2927 } 2928 } 2929 } 2930 } 2931} 2932 2933void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2934 Thread* self = Thread::Current(); 2935 { 2936 MutexLock mu(self, *heap_trim_request_lock_); 2937 if (desired_collector_type_ == desired_collector_type) { 2938 return; 2939 } 2940 heap_transition_or_trim_target_time_ = 2941 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 2942 desired_collector_type_ = desired_collector_type; 2943 } 2944 SignalHeapTrimDaemon(self); 2945} 2946 2947void Heap::RequestHeapTrim() { 2948 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2949 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2950 // a space it will hold its lock and can become a cause of jank. 2951 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2952 // forking. 2953 2954 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2955 // because that only marks object heads, so a large array looks like lots of empty space. We 2956 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2957 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2958 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2959 // not how much use we're making of those pages. 2960 2961 Thread* self = Thread::Current(); 2962 Runtime* runtime = Runtime::Current(); 2963 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2964 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2965 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2966 // as we don't hold the lock while requesting the trim). 2967 return; 2968 } 2969 { 2970 MutexLock mu(self, *heap_trim_request_lock_); 2971 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2972 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2973 // just yet. 2974 return; 2975 } 2976 heap_trim_request_pending_ = true; 2977 uint64_t current_time = NanoTime(); 2978 if (heap_transition_or_trim_target_time_ < current_time) { 2979 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 2980 } 2981 } 2982 // Notify the daemon thread which will actually do the heap trim. 2983 SignalHeapTrimDaemon(self); 2984} 2985 2986void Heap::SignalHeapTrimDaemon(Thread* self) { 2987 JNIEnv* env = self->GetJniEnv(); 2988 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2989 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2990 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2991 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2992 CHECK(!env->ExceptionCheck()); 2993} 2994 2995void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2996 if (rosalloc_space_ != nullptr) { 2997 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2998 } 2999 if (bump_pointer_space_ != nullptr) { 3000 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3001 } 3002} 3003 3004void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3005 if (rosalloc_space_ != nullptr) { 3006 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3007 } 3008} 3009 3010void Heap::RevokeAllThreadLocalBuffers() { 3011 if (rosalloc_space_ != nullptr) { 3012 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3013 } 3014 if (bump_pointer_space_ != nullptr) { 3015 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3016 } 3017} 3018 3019bool Heap::IsGCRequestPending() const { 3020 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3021} 3022 3023void Heap::RunFinalization(JNIEnv* env) { 3024 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3025 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3026 CHECK(WellKnownClasses::java_lang_System != nullptr); 3027 WellKnownClasses::java_lang_System_runFinalization = 3028 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3029 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3030 } 3031 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3032 WellKnownClasses::java_lang_System_runFinalization); 3033} 3034 3035void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 3036 Thread* self = ThreadForEnv(env); 3037 if (native_need_to_run_finalization_) { 3038 RunFinalization(env); 3039 UpdateMaxNativeFootprint(); 3040 native_need_to_run_finalization_ = false; 3041 } 3042 // Total number of native bytes allocated. 3043 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3044 new_native_bytes_allocated += bytes; 3045 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3046 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 3047 collector::kGcTypeFull; 3048 3049 // The second watermark is higher than the gc watermark. If you hit this it means you are 3050 // allocating native objects faster than the GC can keep up with. 3051 if (new_native_bytes_allocated > native_footprint_limit_) { 3052 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3053 // Just finished a GC, attempt to run finalizers. 3054 RunFinalization(env); 3055 CHECK(!env->ExceptionCheck()); 3056 } 3057 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3058 if (new_native_bytes_allocated > native_footprint_limit_) { 3059 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3060 RunFinalization(env); 3061 native_need_to_run_finalization_ = false; 3062 CHECK(!env->ExceptionCheck()); 3063 } 3064 // We have just run finalizers, update the native watermark since it is very likely that 3065 // finalizers released native managed allocations. 3066 UpdateMaxNativeFootprint(); 3067 } else if (!IsGCRequestPending()) { 3068 if (IsGcConcurrent()) { 3069 RequestConcurrentGC(self); 3070 } else { 3071 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3072 } 3073 } 3074 } 3075} 3076 3077void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 3078 int expected_size, new_size; 3079 do { 3080 expected_size = native_bytes_allocated_.LoadRelaxed(); 3081 new_size = expected_size - bytes; 3082 if (UNLIKELY(new_size < 0)) { 3083 ScopedObjectAccess soa(env); 3084 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3085 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 3086 "registered as allocated", bytes, expected_size).c_str()); 3087 break; 3088 } 3089 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, new_size)); 3090} 3091 3092size_t Heap::GetTotalMemory() const { 3093 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3094} 3095 3096void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3097 DCHECK(mod_union_table != nullptr); 3098 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3099} 3100 3101void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3102 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3103 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 3104 c->GetDescriptor().empty()); 3105 CHECK_GE(byte_count, sizeof(mirror::Object)); 3106} 3107 3108void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3109 CHECK(remembered_set != nullptr); 3110 space::Space* space = remembered_set->GetSpace(); 3111 CHECK(space != nullptr); 3112 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3113 remembered_sets_.Put(space, remembered_set); 3114 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3115} 3116 3117void Heap::RemoveRememberedSet(space::Space* space) { 3118 CHECK(space != nullptr); 3119 auto it = remembered_sets_.find(space); 3120 CHECK(it != remembered_sets_.end()); 3121 delete it->second; 3122 remembered_sets_.erase(it); 3123 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3124} 3125 3126void Heap::ClearMarkedObjects() { 3127 // Clear all of the spaces' mark bitmaps. 3128 for (const auto& space : GetContinuousSpaces()) { 3129 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3130 if (space->GetLiveBitmap() != mark_bitmap) { 3131 mark_bitmap->Clear(); 3132 } 3133 } 3134 // Clear the marked objects in the discontinous space object sets. 3135 for (const auto& space : GetDiscontinuousSpaces()) { 3136 space->GetMarkBitmap()->Clear(); 3137 } 3138} 3139 3140} // namespace gc 3141} // namespace art 3142