heap.cc revision 69dbec6d9d55eeb2867949c2791d01dc9aa916c8
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <memory> 24#include <vector> 25 26#include "base/allocator.h" 27#include "base/histogram-inl.h" 28#include "base/stl_util.h" 29#include "common_throws.h" 30#include "cutils/sched_policy.h" 31#include "debugger.h" 32#include "gc/accounting/atomic_stack.h" 33#include "gc/accounting/card_table-inl.h" 34#include "gc/accounting/heap_bitmap-inl.h" 35#include "gc/accounting/mod_union_table.h" 36#include "gc/accounting/mod_union_table-inl.h" 37#include "gc/accounting/remembered_set.h" 38#include "gc/accounting/space_bitmap-inl.h" 39#include "gc/collector/concurrent_copying.h" 40#include "gc/collector/mark_compact.h" 41#include "gc/collector/mark_sweep-inl.h" 42#include "gc/collector/partial_mark_sweep.h" 43#include "gc/collector/semi_space.h" 44#include "gc/collector/sticky_mark_sweep.h" 45#include "gc/reference_processor.h" 46#include "gc/space/bump_pointer_space.h" 47#include "gc/space/dlmalloc_space-inl.h" 48#include "gc/space/image_space.h" 49#include "gc/space/large_object_space.h" 50#include "gc/space/rosalloc_space-inl.h" 51#include "gc/space/space-inl.h" 52#include "gc/space/zygote_space.h" 53#include "entrypoints/quick/quick_alloc_entrypoints.h" 54#include "heap-inl.h" 55#include "image.h" 56#include "mirror/art_field-inl.h" 57#include "mirror/class-inl.h" 58#include "mirror/object.h" 59#include "mirror/object-inl.h" 60#include "mirror/object_array-inl.h" 61#include "mirror/reference-inl.h" 62#include "os.h" 63#include "reflection.h" 64#include "runtime.h" 65#include "ScopedLocalRef.h" 66#include "scoped_thread_state_change.h" 67#include "handle_scope-inl.h" 68#include "thread_list.h" 69#include "well_known_classes.h" 70 71namespace art { 72 73namespace gc { 74 75static constexpr size_t kCollectorTransitionStressIterations = 0; 76static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 77static constexpr bool kGCALotMode = false; 78static constexpr size_t kGcAlotInterval = KB; 79// Minimum amount of remaining bytes before a concurrent GC is triggered. 80static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 81static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 82// Sticky GC throughput adjustment, divided by 4. Increasing this causes sticky GC to occur more 83// relative to partial/full GC. This may be desirable since sticky GCs interfere less with mutator 84// threads (lower pauses, use less memory bandwidth). 85static constexpr double kStickyGcThroughputAdjustment = 1.0; 86// Whether or not we compact the zygote in PreZygoteFork. 87static constexpr bool kCompactZygote = kMovingCollector; 88// How many reserve entries are at the end of the allocation stack, these are only needed if the 89// allocation stack overflows. 90static constexpr size_t kAllocationStackReserveSize = 1024; 91// Default mark stack size in bytes. 92static const size_t kDefaultMarkStackSize = 64 * KB; 93// Define space name. 94static const char* kDlMallocSpaceName[2] = {"main dlmalloc space", "main dlmalloc space 1"}; 95static const char* kRosAllocSpaceName[2] = {"main rosalloc space", "main rosalloc space 1"}; 96static const char* kMemMapSpaceName[2] = {"main space", "main space 1"}; 97static constexpr size_t kGSSBumpPointerSpaceCapacity = 32 * MB; 98 99Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 100 double target_utilization, double foreground_heap_growth_multiplier, 101 size_t capacity, size_t non_moving_space_capacity, const std::string& image_file_name, 102 const InstructionSet image_instruction_set, CollectorType foreground_collector_type, 103 CollectorType background_collector_type, 104 space::LargeObjectSpaceType large_object_space_type, size_t large_object_threshold, 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 zygote_space_(nullptr), 132 large_object_threshold_(large_object_threshold), 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_need_to_run_finalization_(false), 141 // Initially assume we perceive jank in case the process state is never updated. 142 process_state_(kProcessStateJankPerceptible), 143 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 144 total_bytes_freed_ever_(0), 145 total_objects_freed_ever_(0), 146 num_bytes_allocated_(0), 147 native_bytes_allocated_(0), 148 verify_missing_card_marks_(false), 149 verify_system_weaks_(false), 150 verify_pre_gc_heap_(verify_pre_gc_heap), 151 verify_pre_sweeping_heap_(verify_pre_sweeping_heap), 152 verify_post_gc_heap_(verify_post_gc_heap), 153 verify_mod_union_table_(false), 154 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 155 verify_pre_sweeping_rosalloc_(verify_pre_sweeping_rosalloc), 156 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 157 last_gc_time_ns_(NanoTime()), 158 allocation_rate_(0), 159 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 160 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 161 * verification is enabled, we limit the size of allocation stacks to speed up their 162 * searching. 163 */ 164 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 165 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 166 current_allocator_(kAllocatorTypeDlMalloc), 167 current_non_moving_allocator_(kAllocatorTypeNonMoving), 168 bump_pointer_space_(nullptr), 169 temp_space_(nullptr), 170 min_free_(min_free), 171 max_free_(max_free), 172 target_utilization_(target_utilization), 173 foreground_heap_growth_multiplier_(foreground_heap_growth_multiplier), 174 total_wait_time_(0), 175 total_allocation_time_(0), 176 verify_object_mode_(kVerifyObjectModeDisabled), 177 disable_moving_gc_count_(0), 178 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 179 use_tlab_(use_tlab), 180 main_space_backup_(nullptr), 181 min_interval_homogeneous_space_compaction_by_oom_( 182 min_interval_homogeneous_space_compaction_by_oom), 183 last_time_homogeneous_space_compaction_by_oom_(NanoTime()), 184 use_homogeneous_space_compaction_for_oom_(use_homogeneous_space_compaction_for_oom) { 185 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 186 LOG(INFO) << "Heap() entering"; 187 } 188 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 189 // entrypoints. 190 const bool is_zygote = Runtime::Current()->IsZygote(); 191 if (!is_zygote) { 192 // Background compaction is currently not supported for command line runs. 193 if (background_collector_type_ != foreground_collector_type_) { 194 VLOG(heap) << "Disabling background compaction for non zygote"; 195 background_collector_type_ = foreground_collector_type_; 196 } 197 } 198 ChangeCollector(desired_collector_type_); 199 live_bitmap_.reset(new accounting::HeapBitmap(this)); 200 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 201 // Requested begin for the alloc space, to follow the mapped image and oat files 202 byte* requested_alloc_space_begin = nullptr; 203 if (!image_file_name.empty()) { 204 std::string error_msg; 205 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str(), 206 image_instruction_set, 207 &error_msg); 208 if (image_space != nullptr) { 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 } else { 216 LOG(WARNING) << "Could not create image space with image file '" << image_file_name << "'. " 217 << "Attempting to fall back to imageless running. Error was: " << error_msg; 218 } 219 } 220 /* 221 requested_alloc_space_begin -> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 222 +- nonmoving space (non_moving_space_capacity)+- 223 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 224 +-????????????????????????????????????????????+- 225 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 226 +-main alloc space / bump space 1 (capacity_) +- 227 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 228 +-????????????????????????????????????????????+- 229 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 230 +-main alloc space2 / bump space 2 (capacity_)+- 231 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 232 */ 233 bool support_homogeneous_space_compaction = 234 background_collector_type_ == gc::kCollectorTypeHomogeneousSpaceCompact || 235 use_homogeneous_space_compaction_for_oom; 236 // We may use the same space the main space for the non moving space if we don't need to compact 237 // from the main space. 238 // This is not the case if we support homogeneous compaction or have a moving background 239 // collector type. 240 bool separate_non_moving_space = is_zygote || 241 support_homogeneous_space_compaction || IsMovingGc(foreground_collector_type_) || 242 IsMovingGc(background_collector_type_); 243 if (foreground_collector_type == kCollectorTypeGSS) { 244 separate_non_moving_space = false; 245 } 246 std::unique_ptr<MemMap> main_mem_map_1; 247 std::unique_ptr<MemMap> main_mem_map_2; 248 byte* request_begin = requested_alloc_space_begin; 249 if (request_begin != nullptr && separate_non_moving_space) { 250 request_begin += non_moving_space_capacity; 251 } 252 std::string error_str; 253 std::unique_ptr<MemMap> non_moving_space_mem_map; 254 if (separate_non_moving_space) { 255 // Reserve the non moving mem map before the other two since it needs to be at a specific 256 // address. 257 non_moving_space_mem_map.reset( 258 MemMap::MapAnonymous("non moving space", requested_alloc_space_begin, 259 non_moving_space_capacity, PROT_READ | PROT_WRITE, true, &error_str)); 260 CHECK(non_moving_space_mem_map != nullptr) << error_str; 261 // Try to reserve virtual memory at a lower address if we have a separate non moving space. 262 request_begin = reinterpret_cast<byte*>(0x1000000); 263 } 264 // Attempt to create 2 mem maps at or after the requested begin. 265 main_mem_map_1.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[0], request_begin, capacity_, 266 PROT_READ | PROT_WRITE, &error_str)); 267 CHECK(main_mem_map_1.get() != nullptr) << error_str; 268 if (support_homogeneous_space_compaction || 269 background_collector_type_ == kCollectorTypeSS || 270 foreground_collector_type_ == kCollectorTypeSS) { 271 main_mem_map_2.reset(MapAnonymousPreferredAddress(kMemMapSpaceName[1], main_mem_map_1->End(), 272 capacity_, PROT_READ | PROT_WRITE, 273 &error_str)); 274 CHECK(main_mem_map_2.get() != nullptr) << error_str; 275 } 276 // Create the non moving space first so that bitmaps don't take up the address range. 277 if (separate_non_moving_space) { 278 // Non moving space is always dlmalloc since we currently don't have support for multiple 279 // active rosalloc spaces. 280 const size_t size = non_moving_space_mem_map->Size(); 281 non_moving_space_ = space::DlMallocSpace::CreateFromMemMap( 282 non_moving_space_mem_map.release(), "zygote / non moving space", kDefaultStartingSize, 283 initial_size, size, size, false); 284 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 285 CHECK(non_moving_space_ != nullptr) << "Failed creating non moving space " 286 << requested_alloc_space_begin; 287 AddSpace(non_moving_space_); 288 } 289 // Create other spaces based on whether or not we have a moving GC. 290 if (IsMovingGc(foreground_collector_type_) && foreground_collector_type_ != kCollectorTypeGSS) { 291 // Create bump pointer spaces. 292 // We only to create the bump pointer if the foreground collector is a compacting GC. 293 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 294 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 1", 295 main_mem_map_1.release()); 296 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 297 AddSpace(bump_pointer_space_); 298 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 299 main_mem_map_2.release()); 300 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 301 AddSpace(temp_space_); 302 CHECK(separate_non_moving_space); 303 } else { 304 CreateMainMallocSpace(main_mem_map_1.release(), initial_size, growth_limit_, capacity_); 305 CHECK(main_space_ != nullptr); 306 AddSpace(main_space_); 307 if (!separate_non_moving_space) { 308 non_moving_space_ = main_space_; 309 CHECK(!non_moving_space_->CanMoveObjects()); 310 } 311 if (foreground_collector_type_ == kCollectorTypeGSS) { 312 CHECK_EQ(foreground_collector_type_, background_collector_type_); 313 // Create bump pointer spaces instead of a backup space. 314 main_mem_map_2.release(); 315 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space 1", 316 kGSSBumpPointerSpaceCapacity, nullptr); 317 CHECK(bump_pointer_space_ != nullptr); 318 AddSpace(bump_pointer_space_); 319 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", 320 kGSSBumpPointerSpaceCapacity, nullptr); 321 CHECK(temp_space_ != nullptr); 322 AddSpace(temp_space_); 323 } else if (main_mem_map_2.get() != nullptr) { 324 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 325 main_space_backup_.reset(CreateMallocSpaceFromMemMap(main_mem_map_2.release(), initial_size, 326 growth_limit_, capacity_, name, true)); 327 CHECK(main_space_backup_.get() != nullptr); 328 // Add the space so its accounted for in the heap_begin and heap_end. 329 AddSpace(main_space_backup_.get()); 330 } 331 } 332 CHECK(non_moving_space_ != nullptr); 333 CHECK(!non_moving_space_->CanMoveObjects()); 334 // Allocate the large object space. 335 if (large_object_space_type == space::kLargeObjectSpaceTypeFreeList) { 336 large_object_space_ = space::FreeListSpace::Create("free list large object space", nullptr, 337 capacity_); 338 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 339 } else if (large_object_space_type == space::kLargeObjectSpaceTypeMap) { 340 large_object_space_ = space::LargeObjectMapSpace::Create("mem map large object space"); 341 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 342 } else { 343 // Disable the large object space by making the cutoff excessively large. 344 large_object_threshold_ = std::numeric_limits<size_t>::max(); 345 large_object_space_ = nullptr; 346 } 347 if (large_object_space_ != nullptr) { 348 AddSpace(large_object_space_); 349 } 350 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 351 CHECK(!continuous_spaces_.empty()); 352 // Relies on the spaces being sorted. 353 byte* heap_begin = continuous_spaces_.front()->Begin(); 354 byte* heap_end = continuous_spaces_.back()->Limit(); 355 size_t heap_capacity = heap_end - heap_begin; 356 // Remove the main backup space since it slows down the GC to have unused extra spaces. 357 if (main_space_backup_.get() != nullptr) { 358 RemoveSpace(main_space_backup_.get()); 359 } 360 // Allocate the card table. 361 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 362 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 363 // Card cache for now since it makes it easier for us to update the references to the copying 364 // spaces. 365 accounting::ModUnionTable* mod_union_table = 366 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 367 GetImageSpace()); 368 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 369 AddModUnionTable(mod_union_table); 370 if (collector::SemiSpace::kUseRememberedSet && non_moving_space_ != main_space_) { 371 accounting::RememberedSet* non_moving_space_rem_set = 372 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 373 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 374 AddRememberedSet(non_moving_space_rem_set); 375 } 376 // TODO: Count objects in the image space here? 377 num_bytes_allocated_.StoreRelaxed(0); 378 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", kDefaultMarkStackSize, 379 kDefaultMarkStackSize)); 380 const size_t alloc_stack_capacity = max_allocation_stack_size_ + kAllocationStackReserveSize; 381 allocation_stack_.reset(accounting::ObjectStack::Create( 382 "allocation stack", max_allocation_stack_size_, alloc_stack_capacity)); 383 live_stack_.reset(accounting::ObjectStack::Create( 384 "live stack", max_allocation_stack_size_, alloc_stack_capacity)); 385 // It's still too early to take a lock because there are no threads yet, but we can create locks 386 // now. We don't create it earlier to make it clear that you can't use locks during heap 387 // initialization. 388 gc_complete_lock_ = new Mutex("GC complete lock"); 389 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 390 *gc_complete_lock_)); 391 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 392 last_gc_size_ = GetBytesAllocated(); 393 if (ignore_max_footprint_) { 394 SetIdealFootprint(std::numeric_limits<size_t>::max()); 395 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 396 } 397 CHECK_NE(max_allowed_footprint_, 0U); 398 // Create our garbage collectors. 399 for (size_t i = 0; i < 2; ++i) { 400 const bool concurrent = i != 0; 401 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 402 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 403 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 404 } 405 if (kMovingCollector) { 406 // TODO: Clean this up. 407 const bool generational = foreground_collector_type_ == kCollectorTypeGSS; 408 semi_space_collector_ = new collector::SemiSpace(this, generational, 409 generational ? "generational" : ""); 410 garbage_collectors_.push_back(semi_space_collector_); 411 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 412 garbage_collectors_.push_back(concurrent_copying_collector_); 413 mark_compact_collector_ = new collector::MarkCompact(this); 414 garbage_collectors_.push_back(mark_compact_collector_); 415 } 416 if (GetImageSpace() != nullptr && non_moving_space_ != nullptr && 417 (is_zygote || separate_non_moving_space || foreground_collector_type_ == kCollectorTypeGSS)) { 418 // Check that there's no gap between the image space and the non moving space so that the 419 // immune region won't break (eg. due to a large object allocated in the gap). This is only 420 // required when we're the zygote or using GSS. 421 bool no_gap = MemMap::CheckNoGaps(GetImageSpace()->GetMemMap(), 422 non_moving_space_->GetMemMap()); 423 if (!no_gap) { 424 MemMap::DumpMaps(LOG(ERROR)); 425 LOG(FATAL) << "There's a gap between the image space and the main space"; 426 } 427 } 428 if (running_on_valgrind_) { 429 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(false); 430 } 431 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 432 LOG(INFO) << "Heap() exiting"; 433 } 434} 435 436MemMap* Heap::MapAnonymousPreferredAddress(const char* name, byte* request_begin, size_t capacity, 437 int prot_flags, std::string* out_error_str) { 438 while (true) { 439 MemMap* map = MemMap::MapAnonymous(kMemMapSpaceName[0], request_begin, capacity, 440 PROT_READ | PROT_WRITE, true, out_error_str); 441 if (map != nullptr || request_begin == nullptr) { 442 return map; 443 } 444 // Retry a second time with no specified request begin. 445 request_begin = nullptr; 446 } 447 return nullptr; 448} 449 450space::MallocSpace* Heap::CreateMallocSpaceFromMemMap(MemMap* mem_map, size_t initial_size, 451 size_t growth_limit, size_t capacity, 452 const char* name, bool can_move_objects) { 453 space::MallocSpace* malloc_space = nullptr; 454 if (kUseRosAlloc) { 455 // Create rosalloc space. 456 malloc_space = space::RosAllocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 457 initial_size, growth_limit, capacity, 458 low_memory_mode_, can_move_objects); 459 } else { 460 malloc_space = space::DlMallocSpace::CreateFromMemMap(mem_map, name, kDefaultStartingSize, 461 initial_size, growth_limit, capacity, 462 can_move_objects); 463 } 464 if (collector::SemiSpace::kUseRememberedSet) { 465 accounting::RememberedSet* rem_set = 466 new accounting::RememberedSet(std::string(name) + " remembered set", this, malloc_space); 467 CHECK(rem_set != nullptr) << "Failed to create main space remembered set"; 468 AddRememberedSet(rem_set); 469 } 470 CHECK(malloc_space != nullptr) << "Failed to create " << name; 471 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 472 return malloc_space; 473} 474 475void Heap::CreateMainMallocSpace(MemMap* mem_map, size_t initial_size, size_t growth_limit, 476 size_t capacity) { 477 // Is background compaction is enabled? 478 bool can_move_objects = IsMovingGc(background_collector_type_) != 479 IsMovingGc(foreground_collector_type_) || use_homogeneous_space_compaction_for_oom_; 480 // If we are the zygote and don't yet have a zygote space, it means that the zygote fork will 481 // happen in the future. If this happens and we have kCompactZygote enabled we wish to compact 482 // from the main space to the zygote space. If background compaction is enabled, always pass in 483 // that we can move objets. 484 if (kCompactZygote && Runtime::Current()->IsZygote() && !can_move_objects) { 485 // After the zygote we want this to be false if we don't have background compaction enabled so 486 // that getting primitive array elements is faster. 487 // We never have homogeneous compaction with GSS and don't need a space with movable objects. 488 can_move_objects = !HasZygoteSpace() && foreground_collector_type_ != kCollectorTypeGSS; 489 } 490 if (collector::SemiSpace::kUseRememberedSet && main_space_ != nullptr) { 491 RemoveRememberedSet(main_space_); 492 } 493 const char* name = kUseRosAlloc ? kRosAllocSpaceName[0] : kDlMallocSpaceName[0]; 494 main_space_ = CreateMallocSpaceFromMemMap(mem_map, initial_size, growth_limit, capacity, name, 495 can_move_objects); 496 SetSpaceAsDefault(main_space_); 497 VLOG(heap) << "Created main space " << main_space_; 498} 499 500void Heap::ChangeAllocator(AllocatorType allocator) { 501 if (current_allocator_ != allocator) { 502 // These two allocators are only used internally and don't have any entrypoints. 503 CHECK_NE(allocator, kAllocatorTypeLOS); 504 CHECK_NE(allocator, kAllocatorTypeNonMoving); 505 current_allocator_ = allocator; 506 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 507 SetQuickAllocEntryPointsAllocator(current_allocator_); 508 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 509 } 510} 511 512void Heap::DisableMovingGc() { 513 if (IsMovingGc(foreground_collector_type_)) { 514 foreground_collector_type_ = kCollectorTypeCMS; 515 } 516 if (IsMovingGc(background_collector_type_)) { 517 background_collector_type_ = foreground_collector_type_; 518 } 519 TransitionCollector(foreground_collector_type_); 520 ThreadList* tl = Runtime::Current()->GetThreadList(); 521 Thread* self = Thread::Current(); 522 ScopedThreadStateChange tsc(self, kSuspended); 523 tl->SuspendAll(); 524 // Something may have caused the transition to fail. 525 if (!IsMovingGc(collector_type_) && non_moving_space_ != main_space_) { 526 CHECK(main_space_ != nullptr); 527 // The allocation stack may have non movable objects in it. We need to flush it since the GC 528 // can't only handle marking allocation stack objects of one non moving space and one main 529 // space. 530 { 531 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 532 FlushAllocStack(); 533 } 534 main_space_->DisableMovingObjects(); 535 non_moving_space_ = main_space_; 536 CHECK(!non_moving_space_->CanMoveObjects()); 537 } 538 tl->ResumeAll(); 539} 540 541std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 542 if (!IsValidContinuousSpaceObjectAddress(klass)) { 543 return StringPrintf("<non heap address klass %p>", klass); 544 } 545 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 546 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 547 std::string result("["); 548 result += SafeGetClassDescriptor(component_type); 549 return result; 550 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 551 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 552 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 553 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 554 } else { 555 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 556 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 557 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 558 } 559 const DexFile* dex_file = dex_cache->GetDexFile(); 560 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 561 if (class_def_idx == DexFile::kDexNoIndex16) { 562 return "<class def not found>"; 563 } 564 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 565 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 566 return dex_file->GetTypeDescriptor(type_id); 567 } 568} 569 570std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 571 if (obj == nullptr) { 572 return "null"; 573 } 574 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 575 if (klass == nullptr) { 576 return "(class=null)"; 577 } 578 std::string result(SafeGetClassDescriptor(klass)); 579 if (obj->IsClass()) { 580 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 581 } 582 return result; 583} 584 585void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 586 if (obj == nullptr) { 587 stream << "(obj=null)"; 588 return; 589 } 590 if (IsAligned<kObjectAlignment>(obj)) { 591 space::Space* space = nullptr; 592 // Don't use find space since it only finds spaces which actually contain objects instead of 593 // spaces which may contain objects (e.g. cleared bump pointer spaces). 594 for (const auto& cur_space : continuous_spaces_) { 595 if (cur_space->HasAddress(obj)) { 596 space = cur_space; 597 break; 598 } 599 } 600 // Unprotect all the spaces. 601 for (const auto& space : continuous_spaces_) { 602 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 603 } 604 stream << "Object " << obj; 605 if (space != nullptr) { 606 stream << " in space " << *space; 607 } 608 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 609 stream << "\nclass=" << klass; 610 if (klass != nullptr) { 611 stream << " type= " << SafePrettyTypeOf(obj); 612 } 613 // Re-protect the address we faulted on. 614 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 615 } 616} 617 618bool Heap::IsCompilingBoot() const { 619 if (!Runtime::Current()->IsCompiler()) { 620 return false; 621 } 622 for (const auto& space : continuous_spaces_) { 623 if (space->IsImageSpace() || space->IsZygoteSpace()) { 624 return false; 625 } 626 } 627 return true; 628} 629 630bool Heap::HasImageSpace() const { 631 for (const auto& space : continuous_spaces_) { 632 if (space->IsImageSpace()) { 633 return true; 634 } 635 } 636 return false; 637} 638 639void Heap::IncrementDisableMovingGC(Thread* self) { 640 // Need to do this holding the lock to prevent races where the GC is about to run / running when 641 // we attempt to disable it. 642 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 643 MutexLock mu(self, *gc_complete_lock_); 644 ++disable_moving_gc_count_; 645 if (IsMovingGc(collector_type_running_)) { 646 WaitForGcToCompleteLocked(kGcCauseDisableMovingGc, self); 647 } 648} 649 650void Heap::DecrementDisableMovingGC(Thread* self) { 651 MutexLock mu(self, *gc_complete_lock_); 652 CHECK_GE(disable_moving_gc_count_, 0U); 653 --disable_moving_gc_count_; 654} 655 656void Heap::UpdateProcessState(ProcessState process_state) { 657 if (process_state_ != process_state) { 658 process_state_ = process_state; 659 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 660 // Start at index 1 to avoid "is always false" warning. 661 // Have iteration 1 always transition the collector. 662 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 663 ? foreground_collector_type_ : background_collector_type_); 664 usleep(kCollectorTransitionStressWait); 665 } 666 if (process_state_ == kProcessStateJankPerceptible) { 667 // Transition back to foreground right away to prevent jank. 668 RequestCollectorTransition(foreground_collector_type_, 0); 669 } else { 670 // Don't delay for debug builds since we may want to stress test the GC. 671 // If background_collector_type_ is kCollectorTypeHomogeneousSpaceCompact then we have 672 // special handling which does a homogenous space compaction once but then doesn't transition 673 // the collector. 674 RequestCollectorTransition(background_collector_type_, 675 kIsDebugBuild ? 0 : kCollectorTransitionWait); 676 } 677 } 678} 679 680void Heap::CreateThreadPool() { 681 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 682 if (num_threads != 0) { 683 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 684 } 685} 686 687void Heap::VisitObjects(ObjectCallback callback, void* arg) { 688 Thread* self = Thread::Current(); 689 // GCs can move objects, so don't allow this. 690 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 691 if (bump_pointer_space_ != nullptr) { 692 // Visit objects in bump pointer space. 693 bump_pointer_space_->Walk(callback, arg); 694 } 695 // TODO: Switch to standard begin and end to use ranged a based loop. 696 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 697 it < end; ++it) { 698 mirror::Object* obj = *it; 699 if (obj != nullptr && obj->GetClass() != nullptr) { 700 // Avoid the race condition caused by the object not yet being written into the allocation 701 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 702 // there can be nulls on the allocation stack. 703 callback(obj, arg); 704 } 705 } 706 GetLiveBitmap()->Walk(callback, arg); 707 self->EndAssertNoThreadSuspension(old_cause); 708} 709 710void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 711 space::ContinuousSpace* space1 = main_space_ != nullptr ? main_space_ : non_moving_space_; 712 space::ContinuousSpace* space2 = non_moving_space_; 713 // TODO: Generalize this to n bitmaps? 714 CHECK(space1 != nullptr); 715 CHECK(space2 != nullptr); 716 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 717 (large_object_space_ != nullptr ? large_object_space_->GetLiveBitmap() : nullptr), 718 stack); 719} 720 721void Heap::DeleteThreadPool() { 722 thread_pool_.reset(nullptr); 723} 724 725void Heap::AddSpace(space::Space* space) { 726 CHECK(space != nullptr); 727 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 728 if (space->IsContinuousSpace()) { 729 DCHECK(!space->IsDiscontinuousSpace()); 730 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 731 // Continuous spaces don't necessarily have bitmaps. 732 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 733 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 734 if (live_bitmap != nullptr) { 735 CHECK(mark_bitmap != nullptr); 736 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 737 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 738 } 739 continuous_spaces_.push_back(continuous_space); 740 // Ensure that spaces remain sorted in increasing order of start address. 741 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 742 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 743 return a->Begin() < b->Begin(); 744 }); 745 } else { 746 CHECK(space->IsDiscontinuousSpace()); 747 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 748 live_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 749 mark_bitmap_->AddLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 750 discontinuous_spaces_.push_back(discontinuous_space); 751 } 752 if (space->IsAllocSpace()) { 753 alloc_spaces_.push_back(space->AsAllocSpace()); 754 } 755} 756 757void Heap::SetSpaceAsDefault(space::ContinuousSpace* continuous_space) { 758 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 759 if (continuous_space->IsDlMallocSpace()) { 760 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 761 } else if (continuous_space->IsRosAllocSpace()) { 762 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 763 } 764} 765 766void Heap::RemoveSpace(space::Space* space) { 767 DCHECK(space != nullptr); 768 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 769 if (space->IsContinuousSpace()) { 770 DCHECK(!space->IsDiscontinuousSpace()); 771 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 772 // Continuous spaces don't necessarily have bitmaps. 773 accounting::ContinuousSpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 774 accounting::ContinuousSpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 775 if (live_bitmap != nullptr) { 776 DCHECK(mark_bitmap != nullptr); 777 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 778 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 779 } 780 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 781 DCHECK(it != continuous_spaces_.end()); 782 continuous_spaces_.erase(it); 783 } else { 784 DCHECK(space->IsDiscontinuousSpace()); 785 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 786 live_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetLiveBitmap()); 787 mark_bitmap_->RemoveLargeObjectBitmap(discontinuous_space->GetMarkBitmap()); 788 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 789 discontinuous_space); 790 DCHECK(it != discontinuous_spaces_.end()); 791 discontinuous_spaces_.erase(it); 792 } 793 if (space->IsAllocSpace()) { 794 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 795 DCHECK(it != alloc_spaces_.end()); 796 alloc_spaces_.erase(it); 797 } 798} 799 800void Heap::DumpGcPerformanceInfo(std::ostream& os) { 801 // Dump cumulative timings. 802 os << "Dumping cumulative Gc timings\n"; 803 uint64_t total_duration = 0; 804 // Dump cumulative loggers for each GC type. 805 uint64_t total_paused_time = 0; 806 for (auto& collector : garbage_collectors_) { 807 total_duration += collector->GetCumulativeTimings().GetTotalNs(); 808 total_paused_time += collector->GetTotalPausedTimeNs(); 809 collector->DumpPerformanceInfo(os); 810 collector->ResetMeasurements(); 811 } 812 uint64_t allocation_time = 813 static_cast<uint64_t>(total_allocation_time_.LoadRelaxed()) * kTimeAdjust; 814 if (total_duration != 0) { 815 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 816 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 817 os << "Mean GC size throughput: " 818 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 819 os << "Mean GC object throughput: " 820 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 821 } 822 uint64_t total_objects_allocated = GetObjectsAllocatedEver(); 823 os << "Total number of allocations " << total_objects_allocated << "\n"; 824 uint64_t total_bytes_allocated = GetBytesAllocatedEver(); 825 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 826 os << "Free memory " << PrettySize(GetFreeMemory()) << "\n"; 827 os << "Free memory until GC " << PrettySize(GetFreeMemoryUntilGC()) << "\n"; 828 os << "Free memory until OOME " << PrettySize(GetFreeMemoryUntilOOME()) << "\n"; 829 os << "Total memory " << PrettySize(GetTotalMemory()) << "\n"; 830 os << "Max memory " << PrettySize(GetMaxMemory()) << "\n"; 831 if (kMeasureAllocationTime) { 832 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 833 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 834 << "\n"; 835 } 836 if (HasZygoteSpace()) { 837 os << "Zygote space size " << PrettySize(zygote_space_->Size()) << "\n"; 838 } 839 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 840 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 841 BaseMutex::DumpAll(os); 842} 843 844Heap::~Heap() { 845 VLOG(heap) << "Starting ~Heap()"; 846 STLDeleteElements(&garbage_collectors_); 847 // If we don't reset then the mark stack complains in its destructor. 848 allocation_stack_->Reset(); 849 live_stack_->Reset(); 850 STLDeleteValues(&mod_union_tables_); 851 STLDeleteValues(&remembered_sets_); 852 STLDeleteElements(&continuous_spaces_); 853 STLDeleteElements(&discontinuous_spaces_); 854 delete gc_complete_lock_; 855 delete heap_trim_request_lock_; 856 VLOG(heap) << "Finished ~Heap()"; 857} 858 859space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 860 bool fail_ok) const { 861 for (const auto& space : continuous_spaces_) { 862 if (space->Contains(obj)) { 863 return space; 864 } 865 } 866 if (!fail_ok) { 867 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 868 } 869 return NULL; 870} 871 872space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 873 bool fail_ok) const { 874 for (const auto& space : discontinuous_spaces_) { 875 if (space->Contains(obj)) { 876 return space; 877 } 878 } 879 if (!fail_ok) { 880 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 881 } 882 return NULL; 883} 884 885space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 886 space::Space* result = FindContinuousSpaceFromObject(obj, true); 887 if (result != NULL) { 888 return result; 889 } 890 return FindDiscontinuousSpaceFromObject(obj, true); 891} 892 893space::ImageSpace* Heap::GetImageSpace() const { 894 for (const auto& space : continuous_spaces_) { 895 if (space->IsImageSpace()) { 896 return space->AsImageSpace(); 897 } 898 } 899 return NULL; 900} 901 902void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) { 903 std::ostringstream oss; 904 size_t total_bytes_free = GetFreeMemory(); 905 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 906 << " free bytes and " << PrettySize(GetFreeMemoryUntilOOME()) << " until OOM"; 907 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 908 if (total_bytes_free >= byte_count) { 909 space::AllocSpace* space = nullptr; 910 if (allocator_type == kAllocatorTypeNonMoving) { 911 space = non_moving_space_; 912 } else if (allocator_type == kAllocatorTypeRosAlloc || 913 allocator_type == kAllocatorTypeDlMalloc) { 914 space = main_space_; 915 } else if (allocator_type == kAllocatorTypeBumpPointer || 916 allocator_type == kAllocatorTypeTLAB) { 917 space = bump_pointer_space_; 918 } 919 if (space != nullptr) { 920 space->LogFragmentationAllocFailure(oss, byte_count); 921 } 922 } 923 self->ThrowOutOfMemoryError(oss.str().c_str()); 924} 925 926void Heap::DoPendingTransitionOrTrim() { 927 Thread* self = Thread::Current(); 928 CollectorType desired_collector_type; 929 // Wait until we reach the desired transition time. 930 while (true) { 931 uint64_t wait_time; 932 { 933 MutexLock mu(self, *heap_trim_request_lock_); 934 desired_collector_type = desired_collector_type_; 935 uint64_t current_time = NanoTime(); 936 if (current_time >= heap_transition_or_trim_target_time_) { 937 break; 938 } 939 wait_time = heap_transition_or_trim_target_time_ - current_time; 940 } 941 ScopedThreadStateChange tsc(self, kSleeping); 942 usleep(wait_time / 1000); // Usleep takes microseconds. 943 } 944 // Launch homogeneous space compaction if it is desired. 945 if (desired_collector_type == kCollectorTypeHomogeneousSpaceCompact) { 946 if (!CareAboutPauseTimes()) { 947 PerformHomogeneousSpaceCompact(); 948 } 949 // No need to Trim(). Homogeneous space compaction may free more virtual and physical memory. 950 desired_collector_type = collector_type_; 951 return; 952 } 953 // Transition the collector if the desired collector type is not the same as the current 954 // collector type. 955 TransitionCollector(desired_collector_type); 956 if (!CareAboutPauseTimes()) { 957 // Deflate the monitors, this can cause a pause but shouldn't matter since we don't care 958 // about pauses. 959 Runtime* runtime = Runtime::Current(); 960 runtime->GetThreadList()->SuspendAll(); 961 uint64_t start_time = NanoTime(); 962 size_t count = runtime->GetMonitorList()->DeflateMonitors(); 963 VLOG(heap) << "Deflating " << count << " monitors took " 964 << PrettyDuration(NanoTime() - start_time); 965 runtime->GetThreadList()->ResumeAll(); 966 } 967 // Do a heap trim if it is needed. 968 Trim(); 969} 970 971void Heap::Trim() { 972 Thread* self = Thread::Current(); 973 { 974 MutexLock mu(self, *heap_trim_request_lock_); 975 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 976 return; 977 } 978 last_trim_time_ = NanoTime(); 979 heap_trim_request_pending_ = false; 980 } 981 { 982 // Need to do this before acquiring the locks since we don't want to get suspended while 983 // holding any locks. 984 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 985 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 986 // trimming. 987 MutexLock mu(self, *gc_complete_lock_); 988 // Ensure there is only one GC at a time. 989 WaitForGcToCompleteLocked(kGcCauseTrim, self); 990 collector_type_running_ = kCollectorTypeHeapTrim; 991 } 992 uint64_t start_ns = NanoTime(); 993 // Trim the managed spaces. 994 uint64_t total_alloc_space_allocated = 0; 995 uint64_t total_alloc_space_size = 0; 996 uint64_t managed_reclaimed = 0; 997 for (const auto& space : continuous_spaces_) { 998 if (space->IsMallocSpace()) { 999 gc::space::MallocSpace* malloc_space = space->AsMallocSpace(); 1000 if (malloc_space->IsRosAllocSpace() || !CareAboutPauseTimes()) { 1001 // Don't trim dlmalloc spaces if we care about pauses since this can hold the space lock 1002 // for a long period of time. 1003 managed_reclaimed += malloc_space->Trim(); 1004 } 1005 total_alloc_space_size += malloc_space->Size(); 1006 } 1007 } 1008 total_alloc_space_allocated = GetBytesAllocated(); 1009 if (large_object_space_ != nullptr) { 1010 total_alloc_space_allocated -= large_object_space_->GetBytesAllocated(); 1011 } 1012 if (bump_pointer_space_ != nullptr) { 1013 total_alloc_space_allocated -= bump_pointer_space_->Size(); 1014 } 1015 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 1016 static_cast<float>(total_alloc_space_size); 1017 uint64_t gc_heap_end_ns = NanoTime(); 1018 // We never move things in the native heap, so we can finish the GC at this point. 1019 FinishGC(self, collector::kGcTypeNone); 1020 size_t native_reclaimed = 0; 1021 // Only trim the native heap if we don't care about pauses. 1022 if (!CareAboutPauseTimes()) { 1023#if defined(USE_DLMALLOC) 1024 // Trim the native heap. 1025 dlmalloc_trim(0); 1026 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 1027#elif defined(USE_JEMALLOC) 1028 // Jemalloc does it's own internal trimming. 1029#else 1030 UNIMPLEMENTED(WARNING) << "Add trimming support"; 1031#endif 1032 } 1033 uint64_t end_ns = NanoTime(); 1034 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 1035 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 1036 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 1037 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 1038 << "%."; 1039} 1040 1041bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 1042 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 1043 // taking the lock. 1044 if (obj == nullptr) { 1045 return true; 1046 } 1047 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 1048} 1049 1050bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 1051 return FindContinuousSpaceFromObject(obj, true) != nullptr; 1052} 1053 1054bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 1055 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 1056 return false; 1057 } 1058 for (const auto& space : continuous_spaces_) { 1059 if (space->HasAddress(obj)) { 1060 return true; 1061 } 1062 } 1063 return false; 1064} 1065 1066bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 1067 bool search_live_stack, bool sorted) { 1068 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1069 return false; 1070 } 1071 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1072 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1073 if (obj == klass) { 1074 // This case happens for java.lang.Class. 1075 return true; 1076 } 1077 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1078 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1079 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1080 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1081 return temp_space_->Contains(obj); 1082 } 1083 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1084 space::DiscontinuousSpace* d_space = nullptr; 1085 if (c_space != nullptr) { 1086 if (c_space->GetLiveBitmap()->Test(obj)) { 1087 return true; 1088 } 1089 } else { 1090 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1091 if (d_space != nullptr) { 1092 if (d_space->GetLiveBitmap()->Test(obj)) { 1093 return true; 1094 } 1095 } 1096 } 1097 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1098 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1099 if (i > 0) { 1100 NanoSleep(MsToNs(10)); 1101 } 1102 if (search_allocation_stack) { 1103 if (sorted) { 1104 if (allocation_stack_->ContainsSorted(obj)) { 1105 return true; 1106 } 1107 } else if (allocation_stack_->Contains(obj)) { 1108 return true; 1109 } 1110 } 1111 1112 if (search_live_stack) { 1113 if (sorted) { 1114 if (live_stack_->ContainsSorted(obj)) { 1115 return true; 1116 } 1117 } else if (live_stack_->Contains(obj)) { 1118 return true; 1119 } 1120 } 1121 } 1122 // We need to check the bitmaps again since there is a race where we mark something as live and 1123 // then clear the stack containing it. 1124 if (c_space != nullptr) { 1125 if (c_space->GetLiveBitmap()->Test(obj)) { 1126 return true; 1127 } 1128 } else { 1129 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1130 if (d_space != nullptr && d_space->GetLiveBitmap()->Test(obj)) { 1131 return true; 1132 } 1133 } 1134 return false; 1135} 1136 1137std::string Heap::DumpSpaces() const { 1138 std::ostringstream oss; 1139 DumpSpaces(oss); 1140 return oss.str(); 1141} 1142 1143void Heap::DumpSpaces(std::ostream& stream) const { 1144 for (const auto& space : continuous_spaces_) { 1145 accounting::ContinuousSpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1146 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1147 stream << space << " " << *space << "\n"; 1148 if (live_bitmap != nullptr) { 1149 stream << live_bitmap << " " << *live_bitmap << "\n"; 1150 } 1151 if (mark_bitmap != nullptr) { 1152 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1153 } 1154 } 1155 for (const auto& space : discontinuous_spaces_) { 1156 stream << space << " " << *space << "\n"; 1157 } 1158} 1159 1160void Heap::VerifyObjectBody(mirror::Object* obj) { 1161 if (verify_object_mode_ == kVerifyObjectModeDisabled) { 1162 return; 1163 } 1164 1165 // Ignore early dawn of the universe verifications. 1166 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.LoadRelaxed()) < 10 * KB)) { 1167 return; 1168 } 1169 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1170 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>(mirror::Object::ClassOffset()); 1171 CHECK(c != nullptr) << "Null class in object " << obj; 1172 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1173 CHECK(VerifyClassClass(c)); 1174 1175 if (verify_object_mode_ > kVerifyObjectModeFast) { 1176 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1177 CHECK(IsLiveObjectLocked(obj)) << "Object is dead " << obj << "\n" << DumpSpaces(); 1178 } 1179} 1180 1181void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1182 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1183} 1184 1185void Heap::VerifyHeap() { 1186 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1187 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1188} 1189 1190void Heap::RecordFree(uint64_t freed_objects, int64_t freed_bytes) { 1191 // Use signed comparison since freed bytes can be negative when background compaction foreground 1192 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1193 // free list backed space typically increasing memory footprint due to padding and binning. 1194 DCHECK_LE(freed_bytes, static_cast<int64_t>(num_bytes_allocated_.LoadRelaxed())); 1195 // Note: This relies on 2s complement for handling negative freed_bytes. 1196 num_bytes_allocated_.FetchAndSubSequentiallyConsistent(static_cast<ssize_t>(freed_bytes)); 1197 if (Runtime::Current()->HasStatsEnabled()) { 1198 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1199 thread_stats->freed_objects += freed_objects; 1200 thread_stats->freed_bytes += freed_bytes; 1201 // TODO: Do this concurrently. 1202 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1203 global_stats->freed_objects += freed_objects; 1204 global_stats->freed_bytes += freed_bytes; 1205 } 1206} 1207 1208space::RosAllocSpace* Heap::GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const { 1209 for (const auto& space : continuous_spaces_) { 1210 if (space->AsContinuousSpace()->IsRosAllocSpace()) { 1211 if (space->AsContinuousSpace()->AsRosAllocSpace()->GetRosAlloc() == rosalloc) { 1212 return space->AsContinuousSpace()->AsRosAllocSpace(); 1213 } 1214 } 1215 } 1216 return nullptr; 1217} 1218 1219mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1220 size_t alloc_size, size_t* bytes_allocated, 1221 size_t* usable_size, 1222 mirror::Class** klass) { 1223 bool was_default_allocator = allocator == GetCurrentAllocator(); 1224 // Make sure there is no pending exception since we may need to throw an OOME. 1225 self->AssertNoPendingException(); 1226 DCHECK(klass != nullptr); 1227 StackHandleScope<1> hs(self); 1228 HandleWrapper<mirror::Class> h(hs.NewHandleWrapper(klass)); 1229 klass = nullptr; // Invalidate for safety. 1230 // The allocation failed. If the GC is running, block until it completes, and then retry the 1231 // allocation. 1232 collector::GcType last_gc = WaitForGcToComplete(kGcCauseForAlloc, self); 1233 if (last_gc != collector::kGcTypeNone) { 1234 // If we were the default allocator but the allocator changed while we were suspended, 1235 // abort the allocation. 1236 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1237 return nullptr; 1238 } 1239 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1240 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1241 usable_size); 1242 if (ptr != nullptr) { 1243 return ptr; 1244 } 1245 } 1246 1247 collector::GcType tried_type = next_gc_type_; 1248 const bool gc_ran = 1249 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1250 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1251 return nullptr; 1252 } 1253 if (gc_ran) { 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 // Loop through our different Gc types and try to Gc until we get enough free memory. 1262 for (collector::GcType gc_type : gc_plan_) { 1263 if (gc_type == tried_type) { 1264 continue; 1265 } 1266 // Attempt to run the collector, if we succeed, re-try the allocation. 1267 const bool gc_ran = 1268 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1269 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1270 return nullptr; 1271 } 1272 if (gc_ran) { 1273 // Did we free sufficient memory for the allocation to succeed? 1274 mirror::Object* ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, 1275 usable_size); 1276 if (ptr != nullptr) { 1277 return ptr; 1278 } 1279 } 1280 } 1281 // Allocations have failed after GCs; this is an exceptional state. 1282 // Try harder, growing the heap if necessary. 1283 mirror::Object* ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1284 usable_size); 1285 if (ptr != nullptr) { 1286 return ptr; 1287 } 1288 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1289 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1290 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1291 // OOME. 1292 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1293 << " allocation"; 1294 // TODO: Run finalization, but this may cause more allocations to occur. 1295 // We don't need a WaitForGcToComplete here either. 1296 DCHECK(!gc_plan_.empty()); 1297 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1298 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1299 return nullptr; 1300 } 1301 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1302 if (ptr == nullptr) { 1303 const uint64_t current_time = NanoTime(); 1304 switch (allocator) { 1305 case kAllocatorTypeRosAlloc: 1306 // Fall-through. 1307 case kAllocatorTypeDlMalloc: { 1308 if (use_homogeneous_space_compaction_for_oom_ && 1309 current_time - last_time_homogeneous_space_compaction_by_oom_ > 1310 min_interval_homogeneous_space_compaction_by_oom_) { 1311 last_time_homogeneous_space_compaction_by_oom_ = current_time; 1312 HomogeneousSpaceCompactResult result = PerformHomogeneousSpaceCompact(); 1313 switch (result) { 1314 case HomogeneousSpaceCompactResult::kSuccess: 1315 // If the allocation succeeded, we delayed an oom. 1316 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1317 usable_size); 1318 if (ptr != nullptr) { 1319 count_delayed_oom_++; 1320 } 1321 break; 1322 case HomogeneousSpaceCompactResult::kErrorReject: 1323 // Reject due to disabled moving GC. 1324 break; 1325 case HomogeneousSpaceCompactResult::kErrorVMShuttingDown: 1326 // Throw OOM by default. 1327 break; 1328 default: { 1329 LOG(FATAL) << "Unimplemented homogeneous space compaction result " 1330 << static_cast<size_t>(result); 1331 } 1332 } 1333 // Always print that we ran homogeneous space compation since this can cause jank. 1334 VLOG(heap) << "Ran heap homogeneous space compaction, " 1335 << " requested defragmentation " 1336 << count_requested_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1337 << " performed defragmentation " 1338 << count_performed_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1339 << " ignored homogeneous space compaction " 1340 << count_ignored_homogeneous_space_compaction_.LoadSequentiallyConsistent() 1341 << " delayed count = " 1342 << count_delayed_oom_.LoadSequentiallyConsistent(); 1343 } 1344 break; 1345 } 1346 case kAllocatorTypeNonMoving: { 1347 // Try to transition the heap if the allocation failure was due to the space being full. 1348 if (!IsOutOfMemoryOnAllocation<false>(allocator, alloc_size)) { 1349 // If we aren't out of memory then the OOM was probably from the non moving space being 1350 // full. Attempt to disable compaction and turn the main space into a non moving space. 1351 DisableMovingGc(); 1352 // If we are still a moving GC then something must have caused the transition to fail. 1353 if (IsMovingGc(collector_type_)) { 1354 MutexLock mu(self, *gc_complete_lock_); 1355 // If we couldn't disable moving GC, just throw OOME and return null. 1356 LOG(WARNING) << "Couldn't disable moving GC with disable GC count " 1357 << disable_moving_gc_count_; 1358 } else { 1359 LOG(WARNING) << "Disabled moving GC due to the non moving space being full"; 1360 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, 1361 usable_size); 1362 } 1363 } 1364 break; 1365 } 1366 default: { 1367 // Do nothing for others allocators. 1368 } 1369 } 1370 } 1371 // If the allocation hasn't succeeded by this point, throw an OOM error. 1372 if (ptr == nullptr) { 1373 ThrowOutOfMemoryError(self, alloc_size, allocator); 1374 } 1375 return ptr; 1376} 1377 1378void Heap::SetTargetHeapUtilization(float target) { 1379 DCHECK_GT(target, 0.0f); // asserted in Java code 1380 DCHECK_LT(target, 1.0f); 1381 target_utilization_ = target; 1382} 1383 1384size_t Heap::GetObjectsAllocated() const { 1385 size_t total = 0; 1386 for (space::AllocSpace* space : alloc_spaces_) { 1387 total += space->GetObjectsAllocated(); 1388 } 1389 return total; 1390} 1391 1392uint64_t Heap::GetObjectsAllocatedEver() const { 1393 return GetObjectsFreedEver() + GetObjectsAllocated(); 1394} 1395 1396uint64_t Heap::GetBytesAllocatedEver() const { 1397 return GetBytesFreedEver() + GetBytesAllocated(); 1398} 1399 1400class InstanceCounter { 1401 public: 1402 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1403 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1404 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1405 } 1406 static void Callback(mirror::Object* obj, void* arg) 1407 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1408 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1409 mirror::Class* instance_class = obj->GetClass(); 1410 CHECK(instance_class != nullptr); 1411 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1412 if (instance_counter->use_is_assignable_from_) { 1413 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1414 ++instance_counter->counts_[i]; 1415 } 1416 } else if (instance_class == instance_counter->classes_[i]) { 1417 ++instance_counter->counts_[i]; 1418 } 1419 } 1420 } 1421 1422 private: 1423 const std::vector<mirror::Class*>& classes_; 1424 bool use_is_assignable_from_; 1425 uint64_t* const counts_; 1426 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1427}; 1428 1429void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1430 uint64_t* counts) { 1431 // Can't do any GC in this function since this may move classes. 1432 Thread* self = Thread::Current(); 1433 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1434 InstanceCounter counter(classes, use_is_assignable_from, counts); 1435 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1436 VisitObjects(InstanceCounter::Callback, &counter); 1437 self->EndAssertNoThreadSuspension(old_cause); 1438} 1439 1440class InstanceCollector { 1441 public: 1442 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1443 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1444 : class_(c), max_count_(max_count), instances_(instances) { 1445 } 1446 static void Callback(mirror::Object* obj, void* arg) 1447 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1448 DCHECK(arg != nullptr); 1449 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1450 mirror::Class* instance_class = obj->GetClass(); 1451 if (instance_class == instance_collector->class_) { 1452 if (instance_collector->max_count_ == 0 || 1453 instance_collector->instances_.size() < instance_collector->max_count_) { 1454 instance_collector->instances_.push_back(obj); 1455 } 1456 } 1457 } 1458 1459 private: 1460 mirror::Class* class_; 1461 uint32_t max_count_; 1462 std::vector<mirror::Object*>& instances_; 1463 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1464}; 1465 1466void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1467 std::vector<mirror::Object*>& instances) { 1468 // Can't do any GC in this function since this may move classes. 1469 Thread* self = Thread::Current(); 1470 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1471 InstanceCollector collector(c, max_count, instances); 1472 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1473 VisitObjects(&InstanceCollector::Callback, &collector); 1474 self->EndAssertNoThreadSuspension(old_cause); 1475} 1476 1477class ReferringObjectsFinder { 1478 public: 1479 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1480 std::vector<mirror::Object*>& referring_objects) 1481 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1482 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1483 } 1484 1485 static void Callback(mirror::Object* obj, void* arg) 1486 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1487 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1488 } 1489 1490 // For bitmap Visit. 1491 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1492 // annotalysis on visitors. 1493 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1494 o->VisitReferences<true>(*this, VoidFunctor()); 1495 } 1496 1497 // For Object::VisitReferences. 1498 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1499 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1500 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 1501 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1502 referring_objects_.push_back(obj); 1503 } 1504 } 1505 1506 private: 1507 mirror::Object* object_; 1508 uint32_t max_count_; 1509 std::vector<mirror::Object*>& referring_objects_; 1510 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1511}; 1512 1513void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1514 std::vector<mirror::Object*>& referring_objects) { 1515 // Can't do any GC in this function since this may move the object o. 1516 Thread* self = Thread::Current(); 1517 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1518 ReferringObjectsFinder finder(o, max_count, referring_objects); 1519 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1520 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1521 self->EndAssertNoThreadSuspension(old_cause); 1522} 1523 1524void Heap::CollectGarbage(bool clear_soft_references) { 1525 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1526 // last GC will not have necessarily been cleared. 1527 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1528} 1529 1530HomogeneousSpaceCompactResult Heap::PerformHomogeneousSpaceCompact() { 1531 Thread* self = Thread::Current(); 1532 // Inc requested homogeneous space compaction. 1533 count_requested_homogeneous_space_compaction_++; 1534 // Store performed homogeneous space compaction at a new request arrival. 1535 ThreadList* tl = Runtime::Current()->GetThreadList(); 1536 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1537 Locks::mutator_lock_->AssertNotHeld(self); 1538 { 1539 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1540 MutexLock mu(self, *gc_complete_lock_); 1541 // Ensure there is only one GC at a time. 1542 WaitForGcToCompleteLocked(kGcCauseHomogeneousSpaceCompact, self); 1543 // Homogeneous space compaction is a copying transition, can't run it if the moving GC disable count 1544 // is non zero. 1545 // If the collector type changed to something which doesn't benefit from homogeneous space compaction, 1546 // exit. 1547 if (disable_moving_gc_count_ != 0 || IsMovingGc(collector_type_) || 1548 !main_space_->CanMoveObjects()) { 1549 return HomogeneousSpaceCompactResult::kErrorReject; 1550 } 1551 collector_type_running_ = kCollectorTypeHomogeneousSpaceCompact; 1552 } 1553 if (Runtime::Current()->IsShuttingDown(self)) { 1554 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1555 // cause objects to get finalized. 1556 FinishGC(self, collector::kGcTypeNone); 1557 return HomogeneousSpaceCompactResult::kErrorVMShuttingDown; 1558 } 1559 // Suspend all threads. 1560 tl->SuspendAll(); 1561 uint64_t start_time = NanoTime(); 1562 // Launch compaction. 1563 space::MallocSpace* to_space = main_space_backup_.release(); 1564 space::MallocSpace* from_space = main_space_; 1565 to_space->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1566 const uint64_t space_size_before_compaction = from_space->Size(); 1567 AddSpace(to_space); 1568 Compact(to_space, from_space, kGcCauseHomogeneousSpaceCompact); 1569 // Leave as prot read so that we can still run ROSAlloc verification on this space. 1570 from_space->GetMemMap()->Protect(PROT_READ); 1571 const uint64_t space_size_after_compaction = to_space->Size(); 1572 main_space_ = to_space; 1573 main_space_backup_.reset(from_space); 1574 RemoveSpace(from_space); 1575 SetSpaceAsDefault(main_space_); // Set as default to reset the proper dlmalloc space. 1576 // Update performed homogeneous space compaction count. 1577 count_performed_homogeneous_space_compaction_++; 1578 // Print statics log and resume all threads. 1579 uint64_t duration = NanoTime() - start_time; 1580 VLOG(heap) << "Heap homogeneous space compaction took " << PrettyDuration(duration) << " size: " 1581 << PrettySize(space_size_before_compaction) << " -> " 1582 << PrettySize(space_size_after_compaction) << " compact-ratio: " 1583 << std::fixed << static_cast<double>(space_size_after_compaction) / 1584 static_cast<double>(space_size_before_compaction); 1585 tl->ResumeAll(); 1586 // Finish GC. 1587 reference_processor_.EnqueueClearedReferences(self); 1588 GrowForUtilization(semi_space_collector_); 1589 FinishGC(self, collector::kGcTypeFull); 1590 return HomogeneousSpaceCompactResult::kSuccess; 1591} 1592 1593 1594void Heap::TransitionCollector(CollectorType collector_type) { 1595 if (collector_type == collector_type_) { 1596 return; 1597 } 1598 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1599 << " -> " << static_cast<int>(collector_type); 1600 uint64_t start_time = NanoTime(); 1601 uint32_t before_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1602 Runtime* const runtime = Runtime::Current(); 1603 ThreadList* const tl = runtime->GetThreadList(); 1604 Thread* const self = Thread::Current(); 1605 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1606 Locks::mutator_lock_->AssertNotHeld(self); 1607 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1608 // compacting_gc_disable_count_, this should rarely occurs). 1609 for (;;) { 1610 { 1611 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1612 MutexLock mu(self, *gc_complete_lock_); 1613 // Ensure there is only one GC at a time. 1614 WaitForGcToCompleteLocked(kGcCauseCollectorTransition, self); 1615 // Currently we only need a heap transition if we switch from a moving collector to a 1616 // non-moving one, or visa versa. 1617 const bool copying_transition = IsMovingGc(collector_type_) != IsMovingGc(collector_type); 1618 // If someone else beat us to it and changed the collector before we could, exit. 1619 // This is safe to do before the suspend all since we set the collector_type_running_ before 1620 // we exit the loop. If another thread attempts to do the heap transition before we exit, 1621 // then it would get blocked on WaitForGcToCompleteLocked. 1622 if (collector_type == collector_type_) { 1623 return; 1624 } 1625 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1626 if (!copying_transition || disable_moving_gc_count_ == 0) { 1627 // TODO: Not hard code in semi-space collector? 1628 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1629 break; 1630 } 1631 } 1632 usleep(1000); 1633 } 1634 if (runtime->IsShuttingDown(self)) { 1635 // Don't allow heap transitions to happen if the runtime is shutting down since these can 1636 // cause objects to get finalized. 1637 FinishGC(self, collector::kGcTypeNone); 1638 return; 1639 } 1640 tl->SuspendAll(); 1641 switch (collector_type) { 1642 case kCollectorTypeSS: { 1643 if (!IsMovingGc(collector_type_)) { 1644 // Create the bump pointer space from the backup space. 1645 CHECK(main_space_backup_ != nullptr); 1646 std::unique_ptr<MemMap> mem_map(main_space_backup_->ReleaseMemMap()); 1647 // We are transitioning from non moving GC -> moving GC, since we copied from the bump 1648 // pointer space last transition it will be protected. 1649 CHECK(mem_map != nullptr); 1650 mem_map->Protect(PROT_READ | PROT_WRITE); 1651 bump_pointer_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space", 1652 mem_map.release()); 1653 AddSpace(bump_pointer_space_); 1654 Compact(bump_pointer_space_, main_space_, kGcCauseCollectorTransition); 1655 // Use the now empty main space mem map for the bump pointer temp space. 1656 mem_map.reset(main_space_->ReleaseMemMap()); 1657 // Unset the pointers just in case. 1658 if (dlmalloc_space_ == main_space_) { 1659 dlmalloc_space_ = nullptr; 1660 } else if (rosalloc_space_ == main_space_) { 1661 rosalloc_space_ = nullptr; 1662 } 1663 // Remove the main space so that we don't try to trim it, this doens't work for debug 1664 // builds since RosAlloc attempts to read the magic number from a protected page. 1665 RemoveSpace(main_space_); 1666 RemoveRememberedSet(main_space_); 1667 delete main_space_; // Delete the space since it has been removed. 1668 main_space_ = nullptr; 1669 RemoveRememberedSet(main_space_backup_.get()); 1670 main_space_backup_.reset(nullptr); // Deletes the space. 1671 temp_space_ = space::BumpPointerSpace::CreateFromMemMap("Bump pointer space 2", 1672 mem_map.release()); 1673 AddSpace(temp_space_); 1674 } 1675 break; 1676 } 1677 case kCollectorTypeMS: 1678 // Fall through. 1679 case kCollectorTypeCMS: { 1680 if (IsMovingGc(collector_type_)) { 1681 CHECK(temp_space_ != nullptr); 1682 std::unique_ptr<MemMap> mem_map(temp_space_->ReleaseMemMap()); 1683 RemoveSpace(temp_space_); 1684 temp_space_ = nullptr; 1685 mem_map->Protect(PROT_READ | PROT_WRITE); 1686 CreateMainMallocSpace(mem_map.get(), kDefaultInitialSize, mem_map->Size(), 1687 mem_map->Size()); 1688 mem_map.release(); 1689 // Compact to the main space from the bump pointer space, don't need to swap semispaces. 1690 AddSpace(main_space_); 1691 Compact(main_space_, bump_pointer_space_, kGcCauseCollectorTransition); 1692 mem_map.reset(bump_pointer_space_->ReleaseMemMap()); 1693 RemoveSpace(bump_pointer_space_); 1694 bump_pointer_space_ = nullptr; 1695 const char* name = kUseRosAlloc ? kRosAllocSpaceName[1] : kDlMallocSpaceName[1]; 1696 // Temporarily unprotect the backup mem map so rosalloc can write the debug magic number. 1697 if (kIsDebugBuild && kUseRosAlloc) { 1698 mem_map->Protect(PROT_READ | PROT_WRITE); 1699 } 1700 main_space_backup_.reset(CreateMallocSpaceFromMemMap(mem_map.get(), kDefaultInitialSize, 1701 mem_map->Size(), mem_map->Size(), 1702 name, true)); 1703 if (kIsDebugBuild && kUseRosAlloc) { 1704 mem_map->Protect(PROT_NONE); 1705 } 1706 mem_map.release(); 1707 } 1708 break; 1709 } 1710 default: { 1711 LOG(FATAL) << "Attempted to transition to invalid collector type " 1712 << static_cast<size_t>(collector_type); 1713 break; 1714 } 1715 } 1716 ChangeCollector(collector_type); 1717 tl->ResumeAll(); 1718 // Can't call into java code with all threads suspended. 1719 reference_processor_.EnqueueClearedReferences(self); 1720 uint64_t duration = NanoTime() - start_time; 1721 GrowForUtilization(semi_space_collector_); 1722 FinishGC(self, collector::kGcTypeFull); 1723 int32_t after_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 1724 int32_t delta_allocated = before_allocated - after_allocated; 1725 std::string saved_str; 1726 if (delta_allocated >= 0) { 1727 saved_str = " saved at least " + PrettySize(delta_allocated); 1728 } else { 1729 saved_str = " expanded " + PrettySize(-delta_allocated); 1730 } 1731 VLOG(heap) << "Heap transition to " << process_state_ << " took " 1732 << PrettyDuration(duration) << saved_str; 1733} 1734 1735void Heap::ChangeCollector(CollectorType collector_type) { 1736 // TODO: Only do this with all mutators suspended to avoid races. 1737 if (collector_type != collector_type_) { 1738 if (collector_type == kCollectorTypeMC) { 1739 // Don't allow mark compact unless support is compiled in. 1740 CHECK(kMarkCompactSupport); 1741 } 1742 collector_type_ = collector_type; 1743 gc_plan_.clear(); 1744 switch (collector_type_) { 1745 case kCollectorTypeCC: // Fall-through. 1746 case kCollectorTypeMC: // Fall-through. 1747 case kCollectorTypeSS: // Fall-through. 1748 case kCollectorTypeGSS: { 1749 gc_plan_.push_back(collector::kGcTypeFull); 1750 if (use_tlab_) { 1751 ChangeAllocator(kAllocatorTypeTLAB); 1752 } else { 1753 ChangeAllocator(kAllocatorTypeBumpPointer); 1754 } 1755 break; 1756 } 1757 case kCollectorTypeMS: { 1758 gc_plan_.push_back(collector::kGcTypeSticky); 1759 gc_plan_.push_back(collector::kGcTypePartial); 1760 gc_plan_.push_back(collector::kGcTypeFull); 1761 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1762 break; 1763 } 1764 case kCollectorTypeCMS: { 1765 gc_plan_.push_back(collector::kGcTypeSticky); 1766 gc_plan_.push_back(collector::kGcTypePartial); 1767 gc_plan_.push_back(collector::kGcTypeFull); 1768 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1769 break; 1770 } 1771 default: { 1772 LOG(FATAL) << "Unimplemented"; 1773 } 1774 } 1775 if (IsGcConcurrent()) { 1776 concurrent_start_bytes_ = 1777 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1778 } else { 1779 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1780 } 1781 } 1782} 1783 1784// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1785class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1786 public: 1787 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1788 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1789 } 1790 1791 void BuildBins(space::ContinuousSpace* space) { 1792 bin_live_bitmap_ = space->GetLiveBitmap(); 1793 bin_mark_bitmap_ = space->GetMarkBitmap(); 1794 BinContext context; 1795 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1796 context.collector_ = this; 1797 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1798 // Note: This requires traversing the space in increasing order of object addresses. 1799 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1800 // Add the last bin which spans after the last object to the end of the space. 1801 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1802 } 1803 1804 private: 1805 struct BinContext { 1806 uintptr_t prev_; // The end of the previous object. 1807 ZygoteCompactingCollector* collector_; 1808 }; 1809 // Maps from bin sizes to locations. 1810 std::multimap<size_t, uintptr_t> bins_; 1811 // Live bitmap of the space which contains the bins. 1812 accounting::ContinuousSpaceBitmap* bin_live_bitmap_; 1813 // Mark bitmap of the space which contains the bins. 1814 accounting::ContinuousSpaceBitmap* bin_mark_bitmap_; 1815 1816 static void Callback(mirror::Object* obj, void* arg) 1817 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1818 DCHECK(arg != nullptr); 1819 BinContext* context = reinterpret_cast<BinContext*>(arg); 1820 ZygoteCompactingCollector* collector = context->collector_; 1821 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1822 size_t bin_size = object_addr - context->prev_; 1823 // Add the bin consisting of the end of the previous object to the start of the current object. 1824 collector->AddBin(bin_size, context->prev_); 1825 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1826 } 1827 1828 void AddBin(size_t size, uintptr_t position) { 1829 if (size != 0) { 1830 bins_.insert(std::make_pair(size, position)); 1831 } 1832 } 1833 1834 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1835 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1836 // allocator. 1837 return false; 1838 } 1839 1840 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1841 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1842 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1843 mirror::Object* forward_address; 1844 // Find the smallest bin which we can move obj in. 1845 auto it = bins_.lower_bound(object_size); 1846 if (it == bins_.end()) { 1847 // No available space in the bins, place it in the target space instead (grows the zygote 1848 // space). 1849 size_t bytes_allocated; 1850 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1851 if (to_space_live_bitmap_ != nullptr) { 1852 to_space_live_bitmap_->Set(forward_address); 1853 } else { 1854 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1855 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1856 } 1857 } else { 1858 size_t size = it->first; 1859 uintptr_t pos = it->second; 1860 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1861 forward_address = reinterpret_cast<mirror::Object*>(pos); 1862 // Set the live and mark bits so that sweeping system weaks works properly. 1863 bin_live_bitmap_->Set(forward_address); 1864 bin_mark_bitmap_->Set(forward_address); 1865 DCHECK_GE(size, object_size); 1866 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1867 } 1868 // Copy the object over to its new location. 1869 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1870 if (kUseBakerOrBrooksReadBarrier) { 1871 obj->AssertReadBarrierPointer(); 1872 if (kUseBrooksReadBarrier) { 1873 DCHECK_EQ(forward_address->GetReadBarrierPointer(), obj); 1874 forward_address->SetReadBarrierPointer(forward_address); 1875 } 1876 forward_address->AssertReadBarrierPointer(); 1877 } 1878 return forward_address; 1879 } 1880}; 1881 1882void Heap::UnBindBitmaps() { 1883 TimingLogger::ScopedTiming t("UnBindBitmaps", GetCurrentGcIteration()->GetTimings()); 1884 for (const auto& space : GetContinuousSpaces()) { 1885 if (space->IsContinuousMemMapAllocSpace()) { 1886 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1887 if (alloc_space->HasBoundBitmaps()) { 1888 alloc_space->UnBindBitmaps(); 1889 } 1890 } 1891 } 1892} 1893 1894void Heap::PreZygoteFork() { 1895 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1896 Thread* self = Thread::Current(); 1897 MutexLock mu(self, zygote_creation_lock_); 1898 // Try to see if we have any Zygote spaces. 1899 if (HasZygoteSpace()) { 1900 LOG(WARNING) << __FUNCTION__ << " called when we already have a zygote space."; 1901 return; 1902 } 1903 VLOG(heap) << "Starting PreZygoteFork"; 1904 // Trim the pages at the end of the non moving space. 1905 non_moving_space_->Trim(); 1906 // The end of the non-moving space may be protected, unprotect it so that we can copy the zygote 1907 // there. 1908 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1909 const bool same_space = non_moving_space_ == main_space_; 1910 if (kCompactZygote) { 1911 // Can't compact if the non moving space is the same as the main space. 1912 DCHECK(semi_space_collector_ != nullptr); 1913 // Temporarily disable rosalloc verification because the zygote 1914 // compaction will mess up the rosalloc internal metadata. 1915 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1916 ZygoteCompactingCollector zygote_collector(this); 1917 zygote_collector.BuildBins(non_moving_space_); 1918 // Create a new bump pointer space which we will compact into. 1919 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1920 non_moving_space_->Limit()); 1921 // Compact the bump pointer space to a new zygote bump pointer space. 1922 bool reset_main_space = false; 1923 if (IsMovingGc(collector_type_)) { 1924 zygote_collector.SetFromSpace(bump_pointer_space_); 1925 } else { 1926 CHECK(main_space_ != nullptr); 1927 // Copy from the main space. 1928 zygote_collector.SetFromSpace(main_space_); 1929 reset_main_space = true; 1930 } 1931 zygote_collector.SetToSpace(&target_space); 1932 zygote_collector.SetSwapSemiSpaces(false); 1933 zygote_collector.Run(kGcCauseCollectorTransition, false); 1934 if (reset_main_space) { 1935 main_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1936 madvise(main_space_->Begin(), main_space_->Capacity(), MADV_DONTNEED); 1937 MemMap* mem_map = main_space_->ReleaseMemMap(); 1938 RemoveSpace(main_space_); 1939 space::Space* old_main_space = main_space_; 1940 CreateMainMallocSpace(mem_map, kDefaultInitialSize, mem_map->Size(), mem_map->Size()); 1941 delete old_main_space; 1942 AddSpace(main_space_); 1943 } else { 1944 bump_pointer_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1945 } 1946 if (temp_space_ != nullptr) { 1947 CHECK(temp_space_->IsEmpty()); 1948 } 1949 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 1950 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 1951 // Update the end and write out image. 1952 non_moving_space_->SetEnd(target_space.End()); 1953 non_moving_space_->SetLimit(target_space.Limit()); 1954 VLOG(heap) << "Zygote space size " << non_moving_space_->Size() << " bytes"; 1955 } 1956 // Change the collector to the post zygote one. 1957 ChangeCollector(foreground_collector_type_); 1958 // Save the old space so that we can remove it after we complete creating the zygote space. 1959 space::MallocSpace* old_alloc_space = non_moving_space_; 1960 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1961 // the remaining available space. 1962 // Remove the old space before creating the zygote space since creating the zygote space sets 1963 // the old alloc space's bitmaps to nullptr. 1964 RemoveSpace(old_alloc_space); 1965 if (collector::SemiSpace::kUseRememberedSet) { 1966 // Sanity bound check. 1967 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1968 // Remove the remembered set for the now zygote space (the old 1969 // non-moving space). Note now that we have compacted objects into 1970 // the zygote space, the data in the remembered set is no longer 1971 // needed. The zygote space will instead have a mod-union table 1972 // from this point on. 1973 RemoveRememberedSet(old_alloc_space); 1974 } 1975 zygote_space_ = old_alloc_space->CreateZygoteSpace("alloc space", low_memory_mode_, 1976 &non_moving_space_); 1977 CHECK(!non_moving_space_->CanMoveObjects()); 1978 if (same_space) { 1979 main_space_ = non_moving_space_; 1980 SetSpaceAsDefault(main_space_); 1981 } 1982 delete old_alloc_space; 1983 CHECK(HasZygoteSpace()) << "Failed creating zygote space"; 1984 AddSpace(zygote_space_); 1985 non_moving_space_->SetFootprintLimit(non_moving_space_->Capacity()); 1986 AddSpace(non_moving_space_); 1987 // Create the zygote space mod union table. 1988 accounting::ModUnionTable* mod_union_table = 1989 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, 1990 zygote_space_); 1991 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1992 // Set all the cards in the mod-union table since we don't know which objects contain references 1993 // to large objects. 1994 mod_union_table->SetCards(); 1995 AddModUnionTable(mod_union_table); 1996 if (collector::SemiSpace::kUseRememberedSet) { 1997 // Add a new remembered set for the post-zygote non-moving space. 1998 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1999 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 2000 non_moving_space_); 2001 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 2002 << "Failed to create post-zygote non-moving space remembered set"; 2003 AddRememberedSet(post_zygote_non_moving_space_rem_set); 2004 } 2005} 2006 2007void Heap::FlushAllocStack() { 2008 MarkAllocStackAsLive(allocation_stack_.get()); 2009 allocation_stack_->Reset(); 2010} 2011 2012void Heap::MarkAllocStack(accounting::ContinuousSpaceBitmap* bitmap1, 2013 accounting::ContinuousSpaceBitmap* bitmap2, 2014 accounting::LargeObjectBitmap* large_objects, 2015 accounting::ObjectStack* stack) { 2016 DCHECK(bitmap1 != nullptr); 2017 DCHECK(bitmap2 != nullptr); 2018 mirror::Object** limit = stack->End(); 2019 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 2020 const mirror::Object* obj = *it; 2021 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 2022 if (bitmap1->HasAddress(obj)) { 2023 bitmap1->Set(obj); 2024 } else if (bitmap2->HasAddress(obj)) { 2025 bitmap2->Set(obj); 2026 } else { 2027 DCHECK(large_objects != nullptr); 2028 large_objects->Set(obj); 2029 } 2030 } 2031 } 2032} 2033 2034void Heap::SwapSemiSpaces() { 2035 CHECK(bump_pointer_space_ != nullptr); 2036 CHECK(temp_space_ != nullptr); 2037 std::swap(bump_pointer_space_, temp_space_); 2038} 2039 2040void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 2041 space::ContinuousMemMapAllocSpace* source_space, 2042 GcCause gc_cause) { 2043 CHECK(kMovingCollector); 2044 if (target_space != source_space) { 2045 // Don't swap spaces since this isn't a typical semi space collection. 2046 semi_space_collector_->SetSwapSemiSpaces(false); 2047 semi_space_collector_->SetFromSpace(source_space); 2048 semi_space_collector_->SetToSpace(target_space); 2049 semi_space_collector_->Run(gc_cause, false); 2050 } else { 2051 CHECK(target_space->IsBumpPointerSpace()) 2052 << "In-place compaction is only supported for bump pointer spaces"; 2053 mark_compact_collector_->SetSpace(target_space->AsBumpPointerSpace()); 2054 mark_compact_collector_->Run(kGcCauseCollectorTransition, false); 2055 } 2056} 2057 2058collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 2059 bool clear_soft_references) { 2060 Thread* self = Thread::Current(); 2061 Runtime* runtime = Runtime::Current(); 2062 // If the heap can't run the GC, silently fail and return that no GC was run. 2063 switch (gc_type) { 2064 case collector::kGcTypePartial: { 2065 if (!HasZygoteSpace()) { 2066 return collector::kGcTypeNone; 2067 } 2068 break; 2069 } 2070 default: { 2071 // Other GC types don't have any special cases which makes them not runnable. The main case 2072 // here is full GC. 2073 } 2074 } 2075 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 2076 Locks::mutator_lock_->AssertNotHeld(self); 2077 if (self->IsHandlingStackOverflow()) { 2078 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 2079 } 2080 bool compacting_gc; 2081 { 2082 gc_complete_lock_->AssertNotHeld(self); 2083 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2084 MutexLock mu(self, *gc_complete_lock_); 2085 // Ensure there is only one GC at a time. 2086 WaitForGcToCompleteLocked(gc_cause, self); 2087 compacting_gc = IsMovingGc(collector_type_); 2088 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 2089 if (compacting_gc && disable_moving_gc_count_ != 0) { 2090 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 2091 return collector::kGcTypeNone; 2092 } 2093 collector_type_running_ = collector_type_; 2094 } 2095 2096 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 2097 ++runtime->GetStats()->gc_for_alloc_count; 2098 ++self->GetStats()->gc_for_alloc_count; 2099 } 2100 uint64_t gc_start_time_ns = NanoTime(); 2101 uint64_t gc_start_size = GetBytesAllocated(); 2102 // Approximate allocation rate in bytes / second. 2103 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 2104 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 2105 if (LIKELY(ms_delta != 0)) { 2106 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 2107 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 2108 } 2109 2110 DCHECK_LT(gc_type, collector::kGcTypeMax); 2111 DCHECK_NE(gc_type, collector::kGcTypeNone); 2112 2113 collector::GarbageCollector* collector = nullptr; 2114 // TODO: Clean this up. 2115 if (compacting_gc) { 2116 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 2117 current_allocator_ == kAllocatorTypeTLAB); 2118 switch (collector_type_) { 2119 case kCollectorTypeSS: 2120 // Fall-through. 2121 case kCollectorTypeGSS: 2122 semi_space_collector_->SetFromSpace(bump_pointer_space_); 2123 semi_space_collector_->SetToSpace(temp_space_); 2124 semi_space_collector_->SetSwapSemiSpaces(true); 2125 collector = semi_space_collector_; 2126 break; 2127 case kCollectorTypeCC: 2128 collector = concurrent_copying_collector_; 2129 break; 2130 case kCollectorTypeMC: 2131 mark_compact_collector_->SetSpace(bump_pointer_space_); 2132 collector = mark_compact_collector_; 2133 break; 2134 default: 2135 LOG(FATAL) << "Invalid collector type " << static_cast<size_t>(collector_type_); 2136 } 2137 if (collector != mark_compact_collector_) { 2138 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 2139 CHECK(temp_space_->IsEmpty()); 2140 } 2141 gc_type = collector::kGcTypeFull; // TODO: Not hard code this in. 2142 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 2143 current_allocator_ == kAllocatorTypeDlMalloc) { 2144 collector = FindCollectorByGcType(gc_type); 2145 } else { 2146 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 2147 } 2148 CHECK(collector != nullptr) 2149 << "Could not find garbage collector with collector_type=" 2150 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 2151 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 2152 total_objects_freed_ever_ += GetCurrentGcIteration()->GetFreedObjects(); 2153 total_bytes_freed_ever_ += GetCurrentGcIteration()->GetFreedBytes(); 2154 RequestHeapTrim(); 2155 // Enqueue cleared references. 2156 reference_processor_.EnqueueClearedReferences(self); 2157 // Grow the heap so that we know when to perform the next GC. 2158 GrowForUtilization(collector); 2159 const size_t duration = GetCurrentGcIteration()->GetDurationNs(); 2160 const std::vector<uint64_t>& pause_times = GetCurrentGcIteration()->GetPauseTimes(); 2161 // Print the GC if it is an explicit GC (e.g. Runtime.gc()) or a slow GC 2162 // (mutator time blocked >= long_pause_log_threshold_). 2163 bool log_gc = gc_cause == kGcCauseExplicit; 2164 if (!log_gc && CareAboutPauseTimes()) { 2165 // GC for alloc pauses the allocating thread, so consider it as a pause. 2166 log_gc = duration > long_gc_log_threshold_ || 2167 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 2168 for (uint64_t pause : pause_times) { 2169 log_gc = log_gc || pause >= long_pause_log_threshold_; 2170 } 2171 } 2172 if (log_gc) { 2173 const size_t percent_free = GetPercentFree(); 2174 const size_t current_heap_size = GetBytesAllocated(); 2175 const size_t total_memory = GetTotalMemory(); 2176 std::ostringstream pause_string; 2177 for (size_t i = 0; i < pause_times.size(); ++i) { 2178 pause_string << PrettyDuration((pause_times[i] / 1000) * 1000) 2179 << ((i != pause_times.size() - 1) ? "," : ""); 2180 } 2181 LOG(INFO) << gc_cause << " " << collector->GetName() 2182 << " GC freed " << current_gc_iteration_.GetFreedObjects() << "(" 2183 << PrettySize(current_gc_iteration_.GetFreedBytes()) << ") AllocSpace objects, " 2184 << current_gc_iteration_.GetFreedLargeObjects() << "(" 2185 << PrettySize(current_gc_iteration_.GetFreedLargeObjectBytes()) << ") LOS objects, " 2186 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 2187 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 2188 << " total " << PrettyDuration((duration / 1000) * 1000); 2189 VLOG(heap) << ConstDumpable<TimingLogger>(*current_gc_iteration_.GetTimings()); 2190 } 2191 FinishGC(self, gc_type); 2192 // Inform DDMS that a GC completed. 2193 Dbg::GcDidFinish(); 2194 return gc_type; 2195} 2196 2197void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 2198 MutexLock mu(self, *gc_complete_lock_); 2199 collector_type_running_ = kCollectorTypeNone; 2200 if (gc_type != collector::kGcTypeNone) { 2201 last_gc_type_ = gc_type; 2202 } 2203 // Wake anyone who may have been waiting for the GC to complete. 2204 gc_complete_cond_->Broadcast(self); 2205} 2206 2207static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2208 RootType /*root_type*/) { 2209 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 2210 if (*root == obj) { 2211 LOG(INFO) << "Object " << obj << " is a root"; 2212 } 2213} 2214 2215class ScanVisitor { 2216 public: 2217 void operator()(const mirror::Object* obj) const { 2218 LOG(ERROR) << "Would have rescanned object " << obj; 2219 } 2220}; 2221 2222// Verify a reference from an object. 2223class VerifyReferenceVisitor { 2224 public: 2225 explicit VerifyReferenceVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2226 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 2227 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) {} 2228 2229 size_t GetFailureCount() const { 2230 return fail_count_->LoadSequentiallyConsistent(); 2231 } 2232 2233 void operator()(mirror::Class* klass, mirror::Reference* ref) const 2234 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2235 if (verify_referent_) { 2236 VerifyReference(ref, ref->GetReferent(), mirror::Reference::ReferentOffset()); 2237 } 2238 } 2239 2240 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 2241 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2242 VerifyReference(obj, obj->GetFieldObject<mirror::Object>(offset), offset); 2243 } 2244 2245 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2246 return heap_->IsLiveObjectLocked(obj, true, false, true); 2247 } 2248 2249 static void VerifyRootCallback(mirror::Object** root, void* arg, uint32_t thread_id, 2250 RootType root_type) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 2251 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2252 if (!visitor->VerifyReference(nullptr, *root, MemberOffset(0))) { 2253 LOG(ERROR) << "Root " << *root << " is dead with type " << PrettyTypeOf(*root) 2254 << " thread_id= " << thread_id << " root_type= " << root_type; 2255 } 2256 } 2257 2258 private: 2259 // TODO: Fix the no thread safety analysis. 2260 // Returns false on failure. 2261 bool VerifyReference(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 2262 NO_THREAD_SAFETY_ANALYSIS { 2263 if (ref == nullptr || IsLive(ref)) { 2264 // Verify that the reference is live. 2265 return true; 2266 } 2267 if (fail_count_->FetchAndAddSequentiallyConsistent(1) == 0) { 2268 // Print message on only on first failure to prevent spam. 2269 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 2270 } 2271 if (obj != nullptr) { 2272 // Only do this part for non roots. 2273 accounting::CardTable* card_table = heap_->GetCardTable(); 2274 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 2275 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2276 byte* card_addr = card_table->CardFromAddr(obj); 2277 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 2278 << offset << "\n card value = " << static_cast<int>(*card_addr); 2279 if (heap_->IsValidObjectAddress(obj->GetClass())) { 2280 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 2281 } else { 2282 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 2283 } 2284 2285 // Attempt to find the class inside of the recently freed objects. 2286 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 2287 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 2288 space::MallocSpace* space = ref_space->AsMallocSpace(); 2289 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 2290 if (ref_class != nullptr) { 2291 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 2292 << PrettyClass(ref_class); 2293 } else { 2294 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 2295 } 2296 } 2297 2298 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 2299 ref->GetClass()->IsClass()) { 2300 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 2301 } else { 2302 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 2303 << ") is not a valid heap address"; 2304 } 2305 2306 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2307 void* cover_begin = card_table->AddrFromCard(card_addr); 2308 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2309 accounting::CardTable::kCardSize); 2310 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2311 << "-" << cover_end; 2312 accounting::ContinuousSpaceBitmap* bitmap = 2313 heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2314 2315 if (bitmap == nullptr) { 2316 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2317 if (!VerifyClassClass(obj->GetClass())) { 2318 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2319 } 2320 } else { 2321 // Print out how the object is live. 2322 if (bitmap->Test(obj)) { 2323 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2324 } 2325 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2326 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2327 } 2328 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2329 LOG(ERROR) << "Object " << obj << " found in live stack"; 2330 } 2331 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2332 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2333 } 2334 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2335 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2336 } 2337 // Attempt to see if the card table missed the reference. 2338 ScanVisitor scan_visitor; 2339 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2340 card_table->Scan(bitmap, byte_cover_begin, 2341 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2342 } 2343 2344 // Search to see if any of the roots reference our object. 2345 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2346 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2347 2348 // Search to see if any of the roots reference our reference. 2349 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2350 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2351 } 2352 return false; 2353 } 2354 2355 Heap* const heap_; 2356 Atomic<size_t>* const fail_count_; 2357 const bool verify_referent_; 2358}; 2359 2360// Verify all references within an object, for use with HeapBitmap::Visit. 2361class VerifyObjectVisitor { 2362 public: 2363 explicit VerifyObjectVisitor(Heap* heap, Atomic<size_t>* fail_count, bool verify_referent) 2364 : heap_(heap), fail_count_(fail_count), verify_referent_(verify_referent) { 2365 } 2366 2367 void operator()(mirror::Object* obj) const 2368 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2369 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2370 // be live or else how did we find it in the live bitmap? 2371 VerifyReferenceVisitor visitor(heap_, fail_count_, verify_referent_); 2372 // The class doesn't count as a reference but we should verify it anyways. 2373 obj->VisitReferences<true>(visitor, visitor); 2374 } 2375 2376 static void VisitCallback(mirror::Object* obj, void* arg) 2377 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2378 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2379 visitor->operator()(obj); 2380 } 2381 2382 size_t GetFailureCount() const { 2383 return fail_count_->LoadSequentiallyConsistent(); 2384 } 2385 2386 private: 2387 Heap* const heap_; 2388 Atomic<size_t>* const fail_count_; 2389 const bool verify_referent_; 2390}; 2391 2392void Heap::PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2393 // Slow path, the allocation stack push back must have already failed. 2394 DCHECK(!allocation_stack_->AtomicPushBack(*obj)); 2395 do { 2396 // TODO: Add handle VerifyObject. 2397 StackHandleScope<1> hs(self); 2398 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2399 // Push our object into the reserve region of the allocaiton stack. This is only required due 2400 // to heap verification requiring that roots are live (either in the live bitmap or in the 2401 // allocation stack). 2402 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2403 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2404 } while (!allocation_stack_->AtomicPushBack(*obj)); 2405} 2406 2407void Heap::PushOnThreadLocalAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) { 2408 // Slow path, the allocation stack push back must have already failed. 2409 DCHECK(!self->PushOnThreadLocalAllocationStack(*obj)); 2410 mirror::Object** start_address; 2411 mirror::Object** end_address; 2412 while (!allocation_stack_->AtomicBumpBack(kThreadLocalAllocationStackSize, &start_address, 2413 &end_address)) { 2414 // TODO: Add handle VerifyObject. 2415 StackHandleScope<1> hs(self); 2416 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2417 // Push our object into the reserve region of the allocaiton stack. This is only required due 2418 // to heap verification requiring that roots are live (either in the live bitmap or in the 2419 // allocation stack). 2420 CHECK(allocation_stack_->AtomicPushBackIgnoreGrowthLimit(*obj)); 2421 // Push into the reserve allocation stack. 2422 CollectGarbageInternal(collector::kGcTypeSticky, kGcCauseForAlloc, false); 2423 } 2424 self->SetThreadLocalAllocationStack(start_address, end_address); 2425 // Retry on the new thread-local allocation stack. 2426 CHECK(self->PushOnThreadLocalAllocationStack(*obj)); // Must succeed. 2427} 2428 2429// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2430size_t Heap::VerifyHeapReferences(bool verify_referents) { 2431 Thread* self = Thread::Current(); 2432 Locks::mutator_lock_->AssertExclusiveHeld(self); 2433 // Lets sort our allocation stacks so that we can efficiently binary search them. 2434 allocation_stack_->Sort(); 2435 live_stack_->Sort(); 2436 // Since we sorted the allocation stack content, need to revoke all 2437 // thread-local allocation stacks. 2438 RevokeAllThreadLocalAllocationStacks(self); 2439 Atomic<size_t> fail_count_(0); 2440 VerifyObjectVisitor visitor(this, &fail_count_, verify_referents); 2441 // Verify objects in the allocation stack since these will be objects which were: 2442 // 1. Allocated prior to the GC (pre GC verification). 2443 // 2. Allocated during the GC (pre sweep GC verification). 2444 // We don't want to verify the objects in the live stack since they themselves may be 2445 // pointing to dead objects if they are not reachable. 2446 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2447 // Verify the roots: 2448 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRootCallback, &visitor); 2449 if (visitor.GetFailureCount() > 0) { 2450 // Dump mod-union tables. 2451 for (const auto& table_pair : mod_union_tables_) { 2452 accounting::ModUnionTable* mod_union_table = table_pair.second; 2453 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2454 } 2455 // Dump remembered sets. 2456 for (const auto& table_pair : remembered_sets_) { 2457 accounting::RememberedSet* remembered_set = table_pair.second; 2458 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2459 } 2460 DumpSpaces(LOG(ERROR)); 2461 } 2462 return visitor.GetFailureCount(); 2463} 2464 2465class VerifyReferenceCardVisitor { 2466 public: 2467 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2468 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2469 Locks::heap_bitmap_lock_) 2470 : heap_(heap), failed_(failed) { 2471 } 2472 2473 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2474 // annotalysis on visitors. 2475 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2476 NO_THREAD_SAFETY_ANALYSIS { 2477 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset); 2478 // Filter out class references since changing an object's class does not mark the card as dirty. 2479 // Also handles large objects, since the only reference they hold is a class reference. 2480 if (ref != nullptr && !ref->IsClass()) { 2481 accounting::CardTable* card_table = heap_->GetCardTable(); 2482 // If the object is not dirty and it is referencing something in the live stack other than 2483 // class, then it must be on a dirty card. 2484 if (!card_table->AddrIsInCardTable(obj)) { 2485 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2486 *failed_ = true; 2487 } else if (!card_table->IsDirty(obj)) { 2488 // TODO: Check mod-union tables. 2489 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2490 // kCardDirty - 1 if it didnt get touched since we aged it. 2491 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2492 if (live_stack->ContainsSorted(ref)) { 2493 if (live_stack->ContainsSorted(obj)) { 2494 LOG(ERROR) << "Object " << obj << " found in live stack"; 2495 } 2496 if (heap_->GetLiveBitmap()->Test(obj)) { 2497 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2498 } 2499 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2500 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2501 2502 // Print which field of the object is dead. 2503 if (!obj->IsObjectArray()) { 2504 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2505 CHECK(klass != NULL); 2506 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2507 : klass->GetIFields(); 2508 CHECK(fields != NULL); 2509 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2510 mirror::ArtField* cur = fields->Get(i); 2511 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2512 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2513 << PrettyField(cur); 2514 break; 2515 } 2516 } 2517 } else { 2518 mirror::ObjectArray<mirror::Object>* object_array = 2519 obj->AsObjectArray<mirror::Object>(); 2520 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2521 if (object_array->Get(i) == ref) { 2522 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2523 } 2524 } 2525 } 2526 2527 *failed_ = true; 2528 } 2529 } 2530 } 2531 } 2532 2533 private: 2534 Heap* const heap_; 2535 bool* const failed_; 2536}; 2537 2538class VerifyLiveStackReferences { 2539 public: 2540 explicit VerifyLiveStackReferences(Heap* heap) 2541 : heap_(heap), 2542 failed_(false) {} 2543 2544 void operator()(mirror::Object* obj) const 2545 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2546 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2547 obj->VisitReferences<true>(visitor, VoidFunctor()); 2548 } 2549 2550 bool Failed() const { 2551 return failed_; 2552 } 2553 2554 private: 2555 Heap* const heap_; 2556 bool failed_; 2557}; 2558 2559bool Heap::VerifyMissingCardMarks() { 2560 Thread* self = Thread::Current(); 2561 Locks::mutator_lock_->AssertExclusiveHeld(self); 2562 // We need to sort the live stack since we binary search it. 2563 live_stack_->Sort(); 2564 // Since we sorted the allocation stack content, need to revoke all 2565 // thread-local allocation stacks. 2566 RevokeAllThreadLocalAllocationStacks(self); 2567 VerifyLiveStackReferences visitor(this); 2568 GetLiveBitmap()->Visit(visitor); 2569 // We can verify objects in the live stack since none of these should reference dead objects. 2570 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2571 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2572 visitor(*it); 2573 } 2574 } 2575 return !visitor.Failed(); 2576} 2577 2578void Heap::SwapStacks(Thread* self) { 2579 if (kUseThreadLocalAllocationStack) { 2580 live_stack_->AssertAllZero(); 2581 } 2582 allocation_stack_.swap(live_stack_); 2583} 2584 2585void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2586 // This must be called only during the pause. 2587 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2588 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2589 MutexLock mu2(self, *Locks::thread_list_lock_); 2590 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2591 for (Thread* t : thread_list) { 2592 t->RevokeThreadLocalAllocationStack(); 2593 } 2594} 2595 2596void Heap::AssertThreadLocalBuffersAreRevoked(Thread* thread) { 2597 if (kIsDebugBuild) { 2598 if (rosalloc_space_ != nullptr) { 2599 rosalloc_space_->AssertThreadLocalBuffersAreRevoked(thread); 2600 } 2601 if (bump_pointer_space_ != nullptr) { 2602 bump_pointer_space_->AssertThreadLocalBuffersAreRevoked(thread); 2603 } 2604 } 2605} 2606 2607void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2608 if (kIsDebugBuild) { 2609 if (bump_pointer_space_ != nullptr) { 2610 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2611 } 2612 } 2613} 2614 2615accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2616 auto it = mod_union_tables_.find(space); 2617 if (it == mod_union_tables_.end()) { 2618 return nullptr; 2619 } 2620 return it->second; 2621} 2622 2623accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2624 auto it = remembered_sets_.find(space); 2625 if (it == remembered_sets_.end()) { 2626 return nullptr; 2627 } 2628 return it->second; 2629} 2630 2631void Heap::ProcessCards(TimingLogger* timings, bool use_rem_sets) { 2632 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2633 // Clear cards and keep track of cards cleared in the mod-union table. 2634 for (const auto& space : continuous_spaces_) { 2635 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2636 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2637 if (table != nullptr) { 2638 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2639 "ImageModUnionClearCards"; 2640 TimingLogger::ScopedTiming t(name, timings); 2641 table->ClearCards(); 2642 } else if (use_rem_sets && rem_set != nullptr) { 2643 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2644 << static_cast<int>(collector_type_); 2645 TimingLogger::ScopedTiming t("AllocSpaceRemSetClearCards", timings); 2646 rem_set->ClearCards(); 2647 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2648 TimingLogger::ScopedTiming t("AllocSpaceClearCards", timings); 2649 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2650 // were dirty before the GC started. 2651 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2652 // -> clean(cleaning thread). 2653 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2654 // roots and then we scan / update mod union tables after. We will always scan either card. 2655 // If we end up with the non aged card, we scan it it in the pause. 2656 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), 2657 VoidFunctor()); 2658 } 2659 } 2660} 2661 2662static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2663} 2664 2665void Heap::PreGcVerificationPaused(collector::GarbageCollector* gc) { 2666 Thread* const self = Thread::Current(); 2667 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2668 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2669 if (verify_pre_gc_heap_) { 2670 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyHeapReferences", timings); 2671 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2672 size_t failures = VerifyHeapReferences(); 2673 if (failures > 0) { 2674 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2675 << " failures"; 2676 } 2677 } 2678 // Check that all objects which reference things in the live stack are on dirty cards. 2679 if (verify_missing_card_marks_) { 2680 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyMissingCardMarks", timings); 2681 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2682 SwapStacks(self); 2683 // Sort the live stack so that we can quickly binary search it later. 2684 CHECK(VerifyMissingCardMarks()) << "Pre " << gc->GetName() 2685 << " missing card mark verification failed\n" << DumpSpaces(); 2686 SwapStacks(self); 2687 } 2688 if (verify_mod_union_table_) { 2689 TimingLogger::ScopedTiming t("(Paused)PreGcVerifyModUnionTables", timings); 2690 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2691 for (const auto& table_pair : mod_union_tables_) { 2692 accounting::ModUnionTable* mod_union_table = table_pair.second; 2693 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2694 mod_union_table->Verify(); 2695 } 2696 } 2697} 2698 2699void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2700 if (verify_pre_gc_heap_ || verify_missing_card_marks_ || verify_mod_union_table_) { 2701 collector::GarbageCollector::ScopedPause pause(gc); 2702 PreGcVerificationPaused(gc); 2703 } 2704} 2705 2706void Heap::PrePauseRosAllocVerification(collector::GarbageCollector* gc) { 2707 // TODO: Add a new runtime option for this? 2708 if (verify_pre_gc_rosalloc_) { 2709 RosAllocVerification(current_gc_iteration_.GetTimings(), "PreGcRosAllocVerification"); 2710 } 2711} 2712 2713void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2714 Thread* const self = Thread::Current(); 2715 TimingLogger* const timings = current_gc_iteration_.GetTimings(); 2716 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2717 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2718 // reachable objects. 2719 if (verify_pre_sweeping_heap_) { 2720 TimingLogger::ScopedTiming t("(Paused)PostSweepingVerifyHeapReferences", timings); 2721 CHECK_NE(self->GetState(), kRunnable); 2722 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2723 // Swapping bound bitmaps does nothing. 2724 gc->SwapBitmaps(); 2725 // Pass in false since concurrent reference processing can mean that the reference referents 2726 // may point to dead objects at the point which PreSweepingGcVerification is called. 2727 size_t failures = VerifyHeapReferences(false); 2728 if (failures > 0) { 2729 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed with " << failures 2730 << " failures"; 2731 } 2732 gc->SwapBitmaps(); 2733 } 2734 if (verify_pre_sweeping_rosalloc_) { 2735 RosAllocVerification(timings, "PreSweepingRosAllocVerification"); 2736 } 2737} 2738 2739void Heap::PostGcVerificationPaused(collector::GarbageCollector* gc) { 2740 // Only pause if we have to do some verification. 2741 Thread* const self = Thread::Current(); 2742 TimingLogger* const timings = GetCurrentGcIteration()->GetTimings(); 2743 TimingLogger::ScopedTiming t(__FUNCTION__, timings); 2744 if (verify_system_weaks_) { 2745 ReaderMutexLock mu2(self, *Locks::heap_bitmap_lock_); 2746 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2747 mark_sweep->VerifySystemWeaks(); 2748 } 2749 if (verify_post_gc_rosalloc_) { 2750 RosAllocVerification(timings, "(Paused)PostGcRosAllocVerification"); 2751 } 2752 if (verify_post_gc_heap_) { 2753 TimingLogger::ScopedTiming t("(Paused)PostGcVerifyHeapReferences", timings); 2754 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2755 size_t failures = VerifyHeapReferences(); 2756 if (failures > 0) { 2757 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed with " << failures 2758 << " failures"; 2759 } 2760 } 2761} 2762 2763void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2764 if (verify_system_weaks_ || verify_post_gc_rosalloc_ || verify_post_gc_heap_) { 2765 collector::GarbageCollector::ScopedPause pause(gc); 2766 PostGcVerificationPaused(gc); 2767 } 2768} 2769 2770void Heap::RosAllocVerification(TimingLogger* timings, const char* name) { 2771 TimingLogger::ScopedTiming t(name, timings); 2772 for (const auto& space : continuous_spaces_) { 2773 if (space->IsRosAllocSpace()) { 2774 VLOG(heap) << name << " : " << space->GetName(); 2775 space->AsRosAllocSpace()->Verify(); 2776 } 2777 } 2778} 2779 2780collector::GcType Heap::WaitForGcToComplete(GcCause cause, Thread* self) { 2781 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2782 MutexLock mu(self, *gc_complete_lock_); 2783 return WaitForGcToCompleteLocked(cause, self); 2784} 2785 2786collector::GcType Heap::WaitForGcToCompleteLocked(GcCause cause, Thread* self) { 2787 collector::GcType last_gc_type = collector::kGcTypeNone; 2788 uint64_t wait_start = NanoTime(); 2789 while (collector_type_running_ != kCollectorTypeNone) { 2790 ATRACE_BEGIN("GC: Wait For Completion"); 2791 // We must wait, change thread state then sleep on gc_complete_cond_; 2792 gc_complete_cond_->Wait(self); 2793 last_gc_type = last_gc_type_; 2794 ATRACE_END(); 2795 } 2796 uint64_t wait_time = NanoTime() - wait_start; 2797 total_wait_time_ += wait_time; 2798 if (wait_time > long_pause_log_threshold_) { 2799 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time) 2800 << " for cause " << cause; 2801 } 2802 return last_gc_type; 2803} 2804 2805void Heap::DumpForSigQuit(std::ostream& os) { 2806 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2807 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2808 DumpGcPerformanceInfo(os); 2809} 2810 2811size_t Heap::GetPercentFree() { 2812 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / max_allowed_footprint_); 2813} 2814 2815void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2816 if (max_allowed_footprint > GetMaxMemory()) { 2817 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2818 << PrettySize(GetMaxMemory()); 2819 max_allowed_footprint = GetMaxMemory(); 2820 } 2821 max_allowed_footprint_ = max_allowed_footprint; 2822} 2823 2824bool Heap::IsMovableObject(const mirror::Object* obj) const { 2825 if (kMovingCollector) { 2826 space::Space* space = FindContinuousSpaceFromObject(obj, true); 2827 if (space != nullptr) { 2828 // TODO: Check large object? 2829 return space->CanMoveObjects(); 2830 } 2831 } 2832 return false; 2833} 2834 2835void Heap::UpdateMaxNativeFootprint() { 2836 size_t native_size = native_bytes_allocated_.LoadRelaxed(); 2837 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2838 size_t target_size = native_size / GetTargetHeapUtilization(); 2839 if (target_size > native_size + max_free_) { 2840 target_size = native_size + max_free_; 2841 } else if (target_size < native_size + min_free_) { 2842 target_size = native_size + min_free_; 2843 } 2844 native_footprint_gc_watermark_ = std::min(growth_limit_, target_size); 2845} 2846 2847collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2848 for (const auto& collector : garbage_collectors_) { 2849 if (collector->GetCollectorType() == collector_type_ && 2850 collector->GetGcType() == gc_type) { 2851 return collector; 2852 } 2853 } 2854 return nullptr; 2855} 2856 2857double Heap::HeapGrowthMultiplier() const { 2858 // If we don't care about pause times we are background, so return 1.0. 2859 if (!CareAboutPauseTimes() || IsLowMemoryMode()) { 2860 return 1.0; 2861 } 2862 return foreground_heap_growth_multiplier_; 2863} 2864 2865void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2866 // We know what our utilization is at this moment. 2867 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2868 const uint64_t bytes_allocated = GetBytesAllocated(); 2869 last_gc_size_ = bytes_allocated; 2870 last_gc_time_ns_ = NanoTime(); 2871 uint64_t target_size; 2872 collector::GcType gc_type = collector_ran->GetGcType(); 2873 if (gc_type != collector::kGcTypeSticky) { 2874 // Grow the heap for non sticky GC. 2875 const float multiplier = HeapGrowthMultiplier(); // Use the multiplier to grow more for 2876 // foreground. 2877 intptr_t delta = bytes_allocated / GetTargetHeapUtilization() - bytes_allocated; 2878 CHECK_GE(delta, 0); 2879 target_size = bytes_allocated + delta * multiplier; 2880 target_size = std::min(target_size, 2881 bytes_allocated + static_cast<uint64_t>(max_free_ * multiplier)); 2882 target_size = std::max(target_size, 2883 bytes_allocated + static_cast<uint64_t>(min_free_ * multiplier)); 2884 native_need_to_run_finalization_ = true; 2885 next_gc_type_ = collector::kGcTypeSticky; 2886 } else { 2887 collector::GcType non_sticky_gc_type = 2888 HasZygoteSpace() ? collector::kGcTypePartial : collector::kGcTypeFull; 2889 // Find what the next non sticky collector will be. 2890 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2891 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2892 // do another sticky collection next. 2893 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2894 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2895 // if the sticky GC throughput always remained >= the full/partial throughput. 2896 if (current_gc_iteration_.GetEstimatedThroughput() * kStickyGcThroughputAdjustment >= 2897 non_sticky_collector->GetEstimatedMeanThroughput() && 2898 non_sticky_collector->NumberOfIterations() > 0 && 2899 bytes_allocated <= max_allowed_footprint_) { 2900 next_gc_type_ = collector::kGcTypeSticky; 2901 } else { 2902 next_gc_type_ = non_sticky_gc_type; 2903 } 2904 // If we have freed enough memory, shrink the heap back down. 2905 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2906 target_size = bytes_allocated + max_free_; 2907 } else { 2908 target_size = std::max(bytes_allocated, static_cast<uint64_t>(max_allowed_footprint_)); 2909 } 2910 } 2911 if (!ignore_max_footprint_) { 2912 SetIdealFootprint(target_size); 2913 if (IsGcConcurrent()) { 2914 // Calculate when to perform the next ConcurrentGC. 2915 // Calculate the estimated GC duration. 2916 const double gc_duration_seconds = NsToMs(current_gc_iteration_.GetDurationNs()) / 1000.0; 2917 // Estimate how many remaining bytes we will have when we need to start the next GC. 2918 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2919 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2920 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2921 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2922 // A never going to happen situation that from the estimated allocation rate we will exceed 2923 // the applications entire footprint with the given estimated allocation rate. Schedule 2924 // another GC nearly straight away. 2925 remaining_bytes = kMinConcurrentRemainingBytes; 2926 } 2927 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2928 DCHECK_LE(max_allowed_footprint_, GetMaxMemory()); 2929 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2930 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2931 // right away. 2932 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2933 static_cast<size_t>(bytes_allocated)); 2934 } 2935 } 2936} 2937 2938void Heap::ClearGrowthLimit() { 2939 growth_limit_ = capacity_; 2940 non_moving_space_->ClearGrowthLimit(); 2941} 2942 2943void Heap::AddFinalizerReference(Thread* self, mirror::Object** object) { 2944 ScopedObjectAccess soa(self); 2945 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(*object)); 2946 jvalue args[1]; 2947 args[0].l = arg.get(); 2948 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2949 // Restore object in case it gets moved. 2950 *object = soa.Decode<mirror::Object*>(arg.get()); 2951} 2952 2953void Heap::RequestConcurrentGCAndSaveObject(Thread* self, mirror::Object** obj) { 2954 StackHandleScope<1> hs(self); 2955 HandleWrapper<mirror::Object> wrapper(hs.NewHandleWrapper(obj)); 2956 RequestConcurrentGC(self); 2957} 2958 2959void Heap::RequestConcurrentGC(Thread* self) { 2960 // Make sure that we can do a concurrent GC. 2961 Runtime* runtime = Runtime::Current(); 2962 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2963 self->IsHandlingStackOverflow()) { 2964 return; 2965 } 2966 // We already have a request pending, no reason to start more until we update 2967 // concurrent_start_bytes_. 2968 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2969 JNIEnv* env = self->GetJniEnv(); 2970 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2971 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2972 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2973 WellKnownClasses::java_lang_Daemons_requestGC); 2974 CHECK(!env->ExceptionCheck()); 2975} 2976 2977void Heap::ConcurrentGC(Thread* self) { 2978 if (Runtime::Current()->IsShuttingDown(self)) { 2979 return; 2980 } 2981 // Wait for any GCs currently running to finish. 2982 if (WaitForGcToComplete(kGcCauseBackground, self) == collector::kGcTypeNone) { 2983 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2984 // instead. E.g. can't do partial, so do full instead. 2985 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2986 collector::kGcTypeNone) { 2987 for (collector::GcType gc_type : gc_plan_) { 2988 // Attempt to run the collector, if we succeed, we are done. 2989 if (gc_type > next_gc_type_ && 2990 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2991 break; 2992 } 2993 } 2994 } 2995 } 2996} 2997 2998void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2999 Thread* self = Thread::Current(); 3000 { 3001 MutexLock mu(self, *heap_trim_request_lock_); 3002 if (desired_collector_type_ == desired_collector_type) { 3003 return; 3004 } 3005 heap_transition_or_trim_target_time_ = 3006 std::max(heap_transition_or_trim_target_time_, NanoTime() + delta_time); 3007 desired_collector_type_ = desired_collector_type; 3008 } 3009 SignalHeapTrimDaemon(self); 3010} 3011 3012void Heap::RequestHeapTrim() { 3013 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 3014 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 3015 // a space it will hold its lock and can become a cause of jank. 3016 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 3017 // forking. 3018 3019 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 3020 // because that only marks object heads, so a large array looks like lots of empty space. We 3021 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 3022 // to utilization (which is probably inversely proportional to how much benefit we can expect). 3023 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 3024 // not how much use we're making of those pages. 3025 3026 Thread* self = Thread::Current(); 3027 Runtime* runtime = Runtime::Current(); 3028 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 3029 runtime->IsZygote()) { 3030 // Ignore the request if we are the zygote to prevent app launching lag due to sleep in heap 3031 // trimmer daemon. b/17310019 3032 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 3033 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 3034 // as we don't hold the lock while requesting the trim). 3035 return; 3036 } 3037 { 3038 MutexLock mu(self, *heap_trim_request_lock_); 3039 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 3040 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 3041 // just yet. 3042 return; 3043 } 3044 heap_trim_request_pending_ = true; 3045 uint64_t current_time = NanoTime(); 3046 if (heap_transition_or_trim_target_time_ < current_time) { 3047 heap_transition_or_trim_target_time_ = current_time + kHeapTrimWait; 3048 } 3049 } 3050 // Notify the daemon thread which will actually do the heap trim. 3051 SignalHeapTrimDaemon(self); 3052} 3053 3054void Heap::SignalHeapTrimDaemon(Thread* self) { 3055 JNIEnv* env = self->GetJniEnv(); 3056 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 3057 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 3058 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 3059 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 3060 CHECK(!env->ExceptionCheck()); 3061} 3062 3063void Heap::RevokeThreadLocalBuffers(Thread* thread) { 3064 if (rosalloc_space_ != nullptr) { 3065 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3066 } 3067 if (bump_pointer_space_ != nullptr) { 3068 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 3069 } 3070} 3071 3072void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 3073 if (rosalloc_space_ != nullptr) { 3074 rosalloc_space_->RevokeThreadLocalBuffers(thread); 3075 } 3076} 3077 3078void Heap::RevokeAllThreadLocalBuffers() { 3079 if (rosalloc_space_ != nullptr) { 3080 rosalloc_space_->RevokeAllThreadLocalBuffers(); 3081 } 3082 if (bump_pointer_space_ != nullptr) { 3083 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 3084 } 3085} 3086 3087bool Heap::IsGCRequestPending() const { 3088 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 3089} 3090 3091void Heap::RunFinalization(JNIEnv* env) { 3092 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 3093 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 3094 CHECK(WellKnownClasses::java_lang_System != nullptr); 3095 WellKnownClasses::java_lang_System_runFinalization = 3096 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 3097 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 3098 } 3099 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 3100 WellKnownClasses::java_lang_System_runFinalization); 3101} 3102 3103void Heap::RegisterNativeAllocation(JNIEnv* env, size_t bytes) { 3104 Thread* self = ThreadForEnv(env); 3105 if (native_need_to_run_finalization_) { 3106 RunFinalization(env); 3107 UpdateMaxNativeFootprint(); 3108 native_need_to_run_finalization_ = false; 3109 } 3110 // Total number of native bytes allocated. 3111 size_t new_native_bytes_allocated = native_bytes_allocated_.FetchAndAddSequentiallyConsistent(bytes); 3112 new_native_bytes_allocated += bytes; 3113 if (new_native_bytes_allocated > native_footprint_gc_watermark_) { 3114 collector::GcType gc_type = HasZygoteSpace() ? collector::kGcTypePartial : 3115 collector::kGcTypeFull; 3116 3117 // The second watermark is higher than the gc watermark. If you hit this it means you are 3118 // allocating native objects faster than the GC can keep up with. 3119 if (new_native_bytes_allocated > growth_limit_) { 3120 if (WaitForGcToComplete(kGcCauseForNativeAlloc, self) != collector::kGcTypeNone) { 3121 // Just finished a GC, attempt to run finalizers. 3122 RunFinalization(env); 3123 CHECK(!env->ExceptionCheck()); 3124 } 3125 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 3126 if (new_native_bytes_allocated > growth_limit_) { 3127 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3128 RunFinalization(env); 3129 native_need_to_run_finalization_ = false; 3130 CHECK(!env->ExceptionCheck()); 3131 } 3132 // We have just run finalizers, update the native watermark since it is very likely that 3133 // finalizers released native managed allocations. 3134 UpdateMaxNativeFootprint(); 3135 } else if (!IsGCRequestPending()) { 3136 if (IsGcConcurrent()) { 3137 RequestConcurrentGC(self); 3138 } else { 3139 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 3140 } 3141 } 3142 } 3143} 3144 3145void Heap::RegisterNativeFree(JNIEnv* env, size_t bytes) { 3146 size_t expected_size; 3147 do { 3148 expected_size = native_bytes_allocated_.LoadRelaxed(); 3149 if (UNLIKELY(bytes > expected_size)) { 3150 ScopedObjectAccess soa(env); 3151 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 3152 StringPrintf("Attempted to free %zd native bytes with only %zd native bytes " 3153 "registered as allocated", bytes, expected_size).c_str()); 3154 break; 3155 } 3156 } while (!native_bytes_allocated_.CompareExchangeWeakRelaxed(expected_size, 3157 expected_size - bytes)); 3158} 3159 3160size_t Heap::GetTotalMemory() const { 3161 return std::max(max_allowed_footprint_, GetBytesAllocated()); 3162} 3163 3164void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 3165 DCHECK(mod_union_table != nullptr); 3166 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 3167} 3168 3169void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 3170 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 3171 (c->IsVariableSize() || c->GetObjectSize() == byte_count)); 3172 CHECK_GE(byte_count, sizeof(mirror::Object)); 3173} 3174 3175void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 3176 CHECK(remembered_set != nullptr); 3177 space::Space* space = remembered_set->GetSpace(); 3178 CHECK(space != nullptr); 3179 CHECK(remembered_sets_.find(space) == remembered_sets_.end()) << space; 3180 remembered_sets_.Put(space, remembered_set); 3181 CHECK(remembered_sets_.find(space) != remembered_sets_.end()) << space; 3182} 3183 3184void Heap::RemoveRememberedSet(space::Space* space) { 3185 CHECK(space != nullptr); 3186 auto it = remembered_sets_.find(space); 3187 CHECK(it != remembered_sets_.end()); 3188 delete it->second; 3189 remembered_sets_.erase(it); 3190 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 3191} 3192 3193void Heap::ClearMarkedObjects() { 3194 // Clear all of the spaces' mark bitmaps. 3195 for (const auto& space : GetContinuousSpaces()) { 3196 accounting::ContinuousSpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 3197 if (space->GetLiveBitmap() != mark_bitmap) { 3198 mark_bitmap->Clear(); 3199 } 3200 } 3201 // Clear the marked objects in the discontinous space object sets. 3202 for (const auto& space : GetDiscontinuousSpaces()) { 3203 space->GetMarkBitmap()->Clear(); 3204 } 3205} 3206 3207} // namespace gc 3208} // namespace art 3209