heap.cc revision db7f37d57b6ac83abe6815d0cd5c50701b6be821
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 <vector> 24#include <valgrind.h> 25 26#include "base/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/mark_sweep-inl.h" 38#include "gc/collector/partial_mark_sweep.h" 39#include "gc/collector/semi_space.h" 40#include "gc/collector/sticky_mark_sweep.h" 41#include "gc/space/bump_pointer_space.h" 42#include "gc/space/dlmalloc_space-inl.h" 43#include "gc/space/image_space.h" 44#include "gc/space/large_object_space.h" 45#include "gc/space/rosalloc_space-inl.h" 46#include "gc/space/space-inl.h" 47#include "heap-inl.h" 48#include "image.h" 49#include "invoke_arg_array_builder.h" 50#include "mirror/art_field-inl.h" 51#include "mirror/class-inl.h" 52#include "mirror/object.h" 53#include "mirror/object-inl.h" 54#include "mirror/object_array-inl.h" 55#include "object_utils.h" 56#include "os.h" 57#include "runtime.h" 58#include "ScopedLocalRef.h" 59#include "scoped_thread_state_change.h" 60#include "sirt_ref.h" 61#include "thread_list.h" 62#include "UniquePtr.h" 63#include "well_known_classes.h" 64 65namespace art { 66 67extern void SetQuickAllocEntryPointsAllocator(gc::AllocatorType allocator); 68 69namespace gc { 70 71static constexpr bool kGCALotMode = false; 72static constexpr size_t kGcAlotInterval = KB; 73// Minimum amount of remaining bytes before a concurrent GC is triggered. 74static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 75 76Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 77 double target_utilization, size_t capacity, const std::string& image_file_name, 78 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 79 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 80 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 81 bool ignore_max_footprint, bool use_tlab) 82 : non_moving_space_(nullptr), 83 rosalloc_space_(nullptr), 84 dlmalloc_space_(nullptr), 85 main_space_(nullptr), 86 concurrent_gc_(false), 87 collector_type_(kCollectorTypeNone), 88 post_zygote_collector_type_(post_zygote_collector_type), 89 background_collector_type_(background_collector_type), 90 parallel_gc_threads_(parallel_gc_threads), 91 conc_gc_threads_(conc_gc_threads), 92 low_memory_mode_(low_memory_mode), 93 long_pause_log_threshold_(long_pause_log_threshold), 94 long_gc_log_threshold_(long_gc_log_threshold), 95 ignore_max_footprint_(ignore_max_footprint), 96 have_zygote_space_(false), 97 soft_reference_queue_(this), 98 weak_reference_queue_(this), 99 finalizer_reference_queue_(this), 100 phantom_reference_queue_(this), 101 cleared_references_(this), 102 is_gc_running_(false), 103 last_gc_type_(collector::kGcTypeNone), 104 next_gc_type_(collector::kGcTypePartial), 105 capacity_(capacity), 106 growth_limit_(growth_limit), 107 max_allowed_footprint_(initial_size), 108 native_footprint_gc_watermark_(initial_size), 109 native_footprint_limit_(2 * initial_size), 110 native_need_to_run_finalization_(false), 111 // Initially assume we perceive jank in case the process state is never updated. 112 process_state_(kProcessStateJankPerceptible), 113 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 114 total_bytes_freed_ever_(0), 115 total_objects_freed_ever_(0), 116 num_bytes_allocated_(0), 117 native_bytes_allocated_(0), 118 gc_memory_overhead_(0), 119 verify_missing_card_marks_(false), 120 verify_system_weaks_(false), 121 verify_pre_gc_heap_(false), 122 verify_post_gc_heap_(false), 123 verify_mod_union_table_(false), 124 min_alloc_space_size_for_sticky_gc_(1112 * MB), 125 min_remaining_space_for_sticky_gc_(1 * MB), 126 last_trim_time_ms_(0), 127 allocation_rate_(0), 128 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 129 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 130 * verification is enabled, we limit the size of allocation stacks to speed up their 131 * searching. 132 */ 133 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 134 : (kDesiredHeapVerification > kVerifyAllFast) ? KB : MB), 135 current_allocator_(kAllocatorTypeDlMalloc), 136 current_non_moving_allocator_(kAllocatorTypeNonMoving), 137 bump_pointer_space_(nullptr), 138 temp_space_(nullptr), 139 reference_referent_offset_(0), 140 reference_queue_offset_(0), 141 reference_queueNext_offset_(0), 142 reference_pendingNext_offset_(0), 143 finalizer_reference_zombie_offset_(0), 144 min_free_(min_free), 145 max_free_(max_free), 146 target_utilization_(target_utilization), 147 total_wait_time_(0), 148 total_allocation_time_(0), 149 verify_object_mode_(kHeapVerificationNotPermitted), 150 gc_disable_count_(0), 151 running_on_valgrind_(RUNNING_ON_VALGRIND), 152 use_tlab_(use_tlab) { 153 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 154 LOG(INFO) << "Heap() entering"; 155 } 156 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 157 // entrypoints. 158 if (!Runtime::Current()->IsZygote() || !kMovingCollector) { 159 ChangeCollector(post_zygote_collector_type_); 160 } else { 161 // We are the zygote, use bump pointer allocation + semi space collector. 162 ChangeCollector(kCollectorTypeSS); 163 } 164 165 live_bitmap_.reset(new accounting::HeapBitmap(this)); 166 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 167 // Requested begin for the alloc space, to follow the mapped image and oat files 168 byte* requested_alloc_space_begin = nullptr; 169 if (!image_file_name.empty()) { 170 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 171 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 172 AddSpace(image_space); 173 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 174 // isn't going to get in the middle 175 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 176 CHECK_GT(oat_file_end_addr, image_space->End()); 177 if (oat_file_end_addr > requested_alloc_space_begin) { 178 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 179 } 180 } 181 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 182 space::MallocSpace* malloc_space; 183 if (kUseRosAlloc) { 184 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 185 requested_alloc_space_begin, low_memory_mode_); 186 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 187 } else { 188 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 189 requested_alloc_space_begin); 190 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 191 } 192 193 if (kMovingCollector) { 194 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 195 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 196 // issues. 197 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 198 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 199 bump_pointer_space_size, nullptr); 200 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 201 AddSpace(bump_pointer_space_); 202 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 203 nullptr); 204 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 205 AddSpace(temp_space_); 206 } 207 non_moving_space_ = malloc_space; 208 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 209 AddSpace(malloc_space); 210 211 // Allocate the large object space. 212 constexpr bool kUseFreeListSpaceForLOS = false; 213 if (kUseFreeListSpaceForLOS) { 214 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 215 } else { 216 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 217 } 218 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 219 AddSpace(large_object_space_); 220 221 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 222 CHECK(!continuous_spaces_.empty()); 223 // Relies on the spaces being sorted. 224 byte* heap_begin = continuous_spaces_.front()->Begin(); 225 byte* heap_end = continuous_spaces_.back()->Limit(); 226 size_t heap_capacity = heap_end - heap_begin; 227 228 // Allocate the card table. 229 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 230 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 231 232 // Card cache for now since it makes it easier for us to update the references to the copying 233 // spaces. 234 accounting::ModUnionTable* mod_union_table = 235 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 236 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 237 AddModUnionTable(mod_union_table); 238 239 // TODO: Count objects in the image space here. 240 num_bytes_allocated_ = 0; 241 242 // Default mark stack size in bytes. 243 static const size_t default_mark_stack_size = 64 * KB; 244 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 245 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 246 max_allocation_stack_size_)); 247 live_stack_.reset(accounting::ObjectStack::Create("live stack", 248 max_allocation_stack_size_)); 249 250 // It's still too early to take a lock because there are no threads yet, but we can create locks 251 // now. We don't create it earlier to make it clear that you can't use locks during heap 252 // initialization. 253 gc_complete_lock_ = new Mutex("GC complete lock"); 254 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 255 *gc_complete_lock_)); 256 last_gc_time_ns_ = NanoTime(); 257 last_gc_size_ = GetBytesAllocated(); 258 259 if (ignore_max_footprint_) { 260 SetIdealFootprint(std::numeric_limits<size_t>::max()); 261 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 262 } 263 CHECK_NE(max_allowed_footprint_, 0U); 264 265 // Create our garbage collectors. 266 for (size_t i = 0; i < 2; ++i) { 267 const bool concurrent = i != 0; 268 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 269 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 270 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 271 } 272 if (kMovingCollector) { 273 // TODO: Clean this up. 274 semi_space_collector_ = new collector::SemiSpace(this); 275 garbage_collectors_.push_back(semi_space_collector_); 276 } 277 278 if (running_on_valgrind_) { 279 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 280 } 281 282 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 283 LOG(INFO) << "Heap() exiting"; 284 } 285} 286 287void Heap::ChangeAllocator(AllocatorType allocator) { 288 // These two allocators are only used internally and don't have any entrypoints. 289 DCHECK_NE(allocator, kAllocatorTypeLOS); 290 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 291 if (current_allocator_ != allocator) { 292 current_allocator_ = allocator; 293 SetQuickAllocEntryPointsAllocator(current_allocator_); 294 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 295 } 296} 297 298bool Heap::IsCompilingBoot() const { 299 for (const auto& space : continuous_spaces_) { 300 if (space->IsImageSpace()) { 301 return false; 302 } else if (space->IsZygoteSpace()) { 303 return false; 304 } 305 } 306 return true; 307} 308 309bool Heap::HasImageSpace() const { 310 for (const auto& space : continuous_spaces_) { 311 if (space->IsImageSpace()) { 312 return true; 313 } 314 } 315 return false; 316} 317 318void Heap::IncrementDisableGC(Thread* self) { 319 // Need to do this holding the lock to prevent races where the GC is about to run / running when 320 // we attempt to disable it. 321 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 322 MutexLock mu(self, *gc_complete_lock_); 323 WaitForGcToCompleteLocked(self); 324 ++gc_disable_count_; 325} 326 327void Heap::DecrementDisableGC(Thread* self) { 328 MutexLock mu(self, *gc_complete_lock_); 329 CHECK_GE(gc_disable_count_, 0U); 330 --gc_disable_count_; 331} 332 333void Heap::UpdateProcessState(ProcessState process_state) { 334 if (process_state_ != process_state) { 335 process_state_ = process_state; 336 if (process_state_ == kProcessStateJankPerceptible) { 337 TransitionCollector(post_zygote_collector_type_); 338 } else { 339 TransitionCollector(background_collector_type_); 340 } 341 } else { 342 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 343 } 344} 345 346void Heap::CreateThreadPool() { 347 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 348 if (num_threads != 0) { 349 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 350 } 351} 352 353void Heap::VisitObjects(ObjectVisitorCallback callback, void* arg) { 354 Thread* self = Thread::Current(); 355 // GCs can move objects, so don't allow this. 356 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 357 if (bump_pointer_space_ != nullptr) { 358 // Visit objects in bump pointer space. 359 bump_pointer_space_->Walk(callback, arg); 360 } 361 // TODO: Switch to standard begin and end to use ranged a based loop. 362 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 363 it < end; ++it) { 364 mirror::Object* obj = *it; 365 callback(obj, arg); 366 } 367 GetLiveBitmap()->Walk(callback, arg); 368 self->EndAssertNoThreadSuspension(old_cause); 369} 370 371void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 372 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 373 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 374 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 375 // TODO: Generalize this to n bitmaps? 376 if (space1 == nullptr) { 377 DCHECK(space2 != nullptr); 378 space1 = space2; 379 } 380 if (space2 == nullptr) { 381 DCHECK(space1 != nullptr); 382 space2 = space1; 383 } 384 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 385 large_object_space_->GetLiveObjects(), stack); 386} 387 388void Heap::DeleteThreadPool() { 389 thread_pool_.reset(nullptr); 390} 391 392void Heap::AddSpace(space::Space* space, bool set_as_default) { 393 DCHECK(space != nullptr); 394 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 395 if (space->IsContinuousSpace()) { 396 DCHECK(!space->IsDiscontinuousSpace()); 397 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 398 // Continuous spaces don't necessarily have bitmaps. 399 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 400 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 401 if (live_bitmap != nullptr) { 402 DCHECK(mark_bitmap != nullptr); 403 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 404 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 405 } 406 continuous_spaces_.push_back(continuous_space); 407 if (set_as_default) { 408 if (continuous_space->IsDlMallocSpace()) { 409 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 410 } else if (continuous_space->IsRosAllocSpace()) { 411 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 412 } 413 } 414 // Ensure that spaces remain sorted in increasing order of start address. 415 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 416 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 417 return a->Begin() < b->Begin(); 418 }); 419 } else { 420 DCHECK(space->IsDiscontinuousSpace()); 421 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 422 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 423 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 424 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 425 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 426 discontinuous_spaces_.push_back(discontinuous_space); 427 } 428 if (space->IsAllocSpace()) { 429 alloc_spaces_.push_back(space->AsAllocSpace()); 430 } 431} 432 433void Heap::RemoveSpace(space::Space* space) { 434 DCHECK(space != nullptr); 435 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 436 if (space->IsContinuousSpace()) { 437 DCHECK(!space->IsDiscontinuousSpace()); 438 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 439 // Continuous spaces don't necessarily have bitmaps. 440 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 441 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 442 if (live_bitmap != nullptr) { 443 DCHECK(mark_bitmap != nullptr); 444 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 445 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 446 } 447 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 448 DCHECK(it != continuous_spaces_.end()); 449 continuous_spaces_.erase(it); 450 if (continuous_space == dlmalloc_space_) { 451 dlmalloc_space_ = nullptr; 452 } else if (continuous_space == rosalloc_space_) { 453 rosalloc_space_ = nullptr; 454 } 455 if (continuous_space == main_space_) { 456 main_space_ = nullptr; 457 } 458 } else { 459 DCHECK(space->IsDiscontinuousSpace()); 460 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 461 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 462 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 463 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 464 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 465 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 466 discontinuous_space); 467 DCHECK(it != discontinuous_spaces_.end()); 468 discontinuous_spaces_.erase(it); 469 } 470 if (space->IsAllocSpace()) { 471 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 472 DCHECK(it != alloc_spaces_.end()); 473 alloc_spaces_.erase(it); 474 } 475 delete space; 476} 477 478void Heap::RegisterGCAllocation(size_t bytes) { 479 if (this != nullptr) { 480 gc_memory_overhead_.FetchAndAdd(bytes); 481 } 482} 483 484void Heap::RegisterGCDeAllocation(size_t bytes) { 485 if (this != nullptr) { 486 gc_memory_overhead_.FetchAndSub(bytes); 487 } 488} 489 490void Heap::DumpGcPerformanceInfo(std::ostream& os) { 491 // Dump cumulative timings. 492 os << "Dumping cumulative Gc timings\n"; 493 uint64_t total_duration = 0; 494 495 // Dump cumulative loggers for each GC type. 496 uint64_t total_paused_time = 0; 497 for (const auto& collector : garbage_collectors_) { 498 CumulativeLogger& logger = collector->GetCumulativeTimings(); 499 if (logger.GetTotalNs() != 0) { 500 os << Dumpable<CumulativeLogger>(logger); 501 const uint64_t total_ns = logger.GetTotalNs(); 502 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 503 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 504 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 505 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 506 Histogram<uint64_t>::CumulativeData cumulative_data; 507 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 508 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 509 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 510 << collector->GetName() << " freed: " << freed_objects 511 << " objects with total size " << PrettySize(freed_bytes) << "\n" 512 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 513 << PrettySize(freed_bytes / seconds) << "/s\n"; 514 total_duration += total_ns; 515 total_paused_time += total_pause_ns; 516 } 517 } 518 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 519 if (total_duration != 0) { 520 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 521 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 522 os << "Mean GC size throughput: " 523 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 524 os << "Mean GC object throughput: " 525 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 526 } 527 size_t total_objects_allocated = GetObjectsAllocatedEver(); 528 os << "Total number of allocations: " << total_objects_allocated << "\n"; 529 size_t total_bytes_allocated = GetBytesAllocatedEver(); 530 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 531 if (kMeasureAllocationTime) { 532 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 533 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 534 << "\n"; 535 } 536 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 537 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 538 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 539} 540 541Heap::~Heap() { 542 VLOG(heap) << "Starting ~Heap()"; 543 STLDeleteElements(&garbage_collectors_); 544 // If we don't reset then the mark stack complains in its destructor. 545 allocation_stack_->Reset(); 546 live_stack_->Reset(); 547 STLDeleteValues(&mod_union_tables_); 548 STLDeleteElements(&continuous_spaces_); 549 STLDeleteElements(&discontinuous_spaces_); 550 delete gc_complete_lock_; 551 VLOG(heap) << "Finished ~Heap()"; 552} 553 554space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 555 bool fail_ok) const { 556 for (const auto& space : continuous_spaces_) { 557 if (space->Contains(obj)) { 558 return space; 559 } 560 } 561 if (!fail_ok) { 562 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 563 } 564 return NULL; 565} 566 567space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 568 bool fail_ok) const { 569 for (const auto& space : discontinuous_spaces_) { 570 if (space->Contains(obj)) { 571 return space; 572 } 573 } 574 if (!fail_ok) { 575 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 576 } 577 return NULL; 578} 579 580space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 581 space::Space* result = FindContinuousSpaceFromObject(obj, true); 582 if (result != NULL) { 583 return result; 584 } 585 return FindDiscontinuousSpaceFromObject(obj, true); 586} 587 588struct SoftReferenceArgs { 589 RootVisitor* is_marked_callback_; 590 RootVisitor* recursive_mark_callback_; 591 void* arg_; 592}; 593 594mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 595 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 596 // TODO: Not preserve all soft references. 597 return args->recursive_mark_callback_(obj, args->arg_); 598} 599 600// Process reference class instances and schedule finalizations. 601void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 602 RootVisitor* is_marked_callback, 603 RootVisitor* recursive_mark_object_callback, void* arg) { 604 // Unless we are in the zygote or required to clear soft references with white references, 605 // preserve some white referents. 606 if (!clear_soft && !Runtime::Current()->IsZygote()) { 607 SoftReferenceArgs soft_reference_args; 608 soft_reference_args.is_marked_callback_ = is_marked_callback; 609 soft_reference_args.recursive_mark_callback_ = recursive_mark_object_callback; 610 soft_reference_args.arg_ = arg; 611 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 612 &soft_reference_args); 613 } 614 timings.StartSplit("ProcessReferences"); 615 // Clear all remaining soft and weak references with white referents. 616 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 617 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 618 timings.EndSplit(); 619 // Preserve all white objects with finalize methods and schedule them for finalization. 620 timings.StartSplit("EnqueueFinalizerReferences"); 621 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 622 recursive_mark_object_callback, arg); 623 timings.EndSplit(); 624 timings.StartSplit("ProcessReferences"); 625 // Clear all f-reachable soft and weak references with white referents. 626 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 627 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 628 // Clear all phantom references with white referents. 629 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 630 // At this point all reference queues other than the cleared references should be empty. 631 DCHECK(soft_reference_queue_.IsEmpty()); 632 DCHECK(weak_reference_queue_.IsEmpty()); 633 DCHECK(finalizer_reference_queue_.IsEmpty()); 634 DCHECK(phantom_reference_queue_.IsEmpty()); 635 timings.EndSplit(); 636} 637 638bool Heap::IsEnqueued(mirror::Object* ref) const { 639 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 640 // will always be non-null. 641 return ref->GetFieldObject<mirror::Object*>(GetReferencePendingNextOffset(), false) != nullptr; 642} 643 644bool Heap::IsEnqueuable(const mirror::Object* ref) const { 645 DCHECK(ref != nullptr); 646 const mirror::Object* queue = 647 ref->GetFieldObject<mirror::Object*>(GetReferenceQueueOffset(), false); 648 const mirror::Object* queue_next = 649 ref->GetFieldObject<mirror::Object*>(GetReferenceQueueNextOffset(), false); 650 return queue != nullptr && queue_next == nullptr; 651} 652 653// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 654// marked, put it on the appropriate list in the heap for later processing. 655void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 656 RootVisitor mark_visitor, void* arg) { 657 DCHECK(klass != nullptr); 658 DCHECK(klass->IsReferenceClass()); 659 DCHECK(obj != nullptr); 660 mirror::Object* referent = GetReferenceReferent(obj); 661 if (referent != nullptr) { 662 mirror::Object* forward_address = mark_visitor(referent, arg); 663 // Null means that the object is not currently marked. 664 if (forward_address == nullptr) { 665 Thread* self = Thread::Current(); 666 // TODO: Remove these locks, and use atomic stacks for storing references? 667 // We need to check that the references haven't already been enqueued since we can end up 668 // scanning the same reference multiple times due to dirty cards. 669 if (klass->IsSoftReferenceClass()) { 670 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 671 } else if (klass->IsWeakReferenceClass()) { 672 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 673 } else if (klass->IsFinalizerReferenceClass()) { 674 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 675 } else if (klass->IsPhantomReferenceClass()) { 676 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 677 } else { 678 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 679 << klass->GetAccessFlags(); 680 } 681 } else if (referent != forward_address) { 682 // Referent is already marked and we need to update it. 683 SetReferenceReferent(obj, forward_address); 684 } 685 } 686} 687 688space::ImageSpace* Heap::GetImageSpace() const { 689 for (const auto& space : continuous_spaces_) { 690 if (space->IsImageSpace()) { 691 return space->AsImageSpace(); 692 } 693 } 694 return NULL; 695} 696 697static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 698 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 699 if (used_bytes < chunk_size) { 700 size_t chunk_free_bytes = chunk_size - used_bytes; 701 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 702 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 703 } 704} 705 706void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 707 std::ostringstream oss; 708 int64_t total_bytes_free = GetFreeMemory(); 709 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 710 << " free bytes"; 711 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 712 if (!large_object_allocation && total_bytes_free >= byte_count) { 713 size_t max_contiguous_allocation = 0; 714 for (const auto& space : continuous_spaces_) { 715 if (space->IsMallocSpace()) { 716 // To allow the Walk/InspectAll() to exclusively-lock the mutator 717 // lock, temporarily release the shared access to the mutator 718 // lock here by transitioning to the suspended state. 719 Locks::mutator_lock_->AssertSharedHeld(self); 720 self->TransitionFromRunnableToSuspended(kSuspended); 721 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 722 self->TransitionFromSuspendedToRunnable(); 723 Locks::mutator_lock_->AssertSharedHeld(self); 724 } 725 } 726 oss << "; failed due to fragmentation (largest possible contiguous allocation " 727 << max_contiguous_allocation << " bytes)"; 728 } 729 self->ThrowOutOfMemoryError(oss.str().c_str()); 730} 731 732void Heap::Trim() { 733 uint64_t start_ns = NanoTime(); 734 // Trim the managed spaces. 735 uint64_t total_alloc_space_allocated = 0; 736 uint64_t total_alloc_space_size = 0; 737 uint64_t managed_reclaimed = 0; 738 for (const auto& space : continuous_spaces_) { 739 if (space->IsMallocSpace() && !space->IsZygoteSpace()) { 740 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 741 total_alloc_space_size += alloc_space->Size(); 742 managed_reclaimed += alloc_space->Trim(); 743 } 744 } 745 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 746 bump_pointer_space_->Size(); 747 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 748 static_cast<float>(total_alloc_space_size); 749 uint64_t gc_heap_end_ns = NanoTime(); 750 // Trim the native heap. 751 dlmalloc_trim(0); 752 size_t native_reclaimed = 0; 753 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 754 uint64_t end_ns = NanoTime(); 755 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 756 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 757 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 758 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 759 << "%."; 760} 761 762bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 763 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 764 // taking the lock. 765 if (obj == nullptr) { 766 return true; 767 } 768 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 769} 770 771bool Heap::IsHeapAddress(const mirror::Object* obj) const { 772 if (kMovingCollector && bump_pointer_space_->HasAddress(obj)) { 773 return true; 774 } 775 // TODO: This probably doesn't work for large objects. 776 return FindSpaceFromObject(obj, true) != nullptr; 777} 778 779bool Heap::IsLiveObjectLocked(const mirror::Object* obj, bool search_allocation_stack, 780 bool search_live_stack, bool sorted) { 781 // Locks::heap_bitmap_lock_->AssertReaderHeld(Thread::Current()); 782 if (obj == nullptr || UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 783 return false; 784 } 785 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 786 space::DiscontinuousSpace* d_space = NULL; 787 if (c_space != NULL) { 788 if (c_space->GetLiveBitmap()->Test(obj)) { 789 return true; 790 } 791 } else if (bump_pointer_space_->Contains(obj) || temp_space_->Contains(obj)) { 792 return true; 793 } else { 794 d_space = FindDiscontinuousSpaceFromObject(obj, true); 795 if (d_space != NULL) { 796 if (d_space->GetLiveObjects()->Test(obj)) { 797 return true; 798 } 799 } 800 } 801 // This is covering the allocation/live stack swapping that is done without mutators suspended. 802 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 803 if (i > 0) { 804 NanoSleep(MsToNs(10)); 805 } 806 if (search_allocation_stack) { 807 if (sorted) { 808 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 809 return true; 810 } 811 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 812 return true; 813 } 814 } 815 816 if (search_live_stack) { 817 if (sorted) { 818 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 819 return true; 820 } 821 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 822 return true; 823 } 824 } 825 } 826 // We need to check the bitmaps again since there is a race where we mark something as live and 827 // then clear the stack containing it. 828 if (c_space != NULL) { 829 if (c_space->GetLiveBitmap()->Test(obj)) { 830 return true; 831 } 832 } else { 833 d_space = FindDiscontinuousSpaceFromObject(obj, true); 834 if (d_space != NULL && d_space->GetLiveObjects()->Test(obj)) { 835 return true; 836 } 837 } 838 return false; 839} 840 841void Heap::VerifyObjectImpl(const mirror::Object* obj) { 842 if (Thread::Current() == NULL || 843 Runtime::Current()->GetThreadList()->GetLockOwner() == Thread::Current()->GetTid()) { 844 return; 845 } 846 VerifyObjectBody(obj); 847} 848 849void Heap::DumpSpaces(std::ostream& stream) { 850 for (const auto& space : continuous_spaces_) { 851 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 852 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 853 stream << space << " " << *space << "\n"; 854 if (live_bitmap != nullptr) { 855 stream << live_bitmap << " " << *live_bitmap << "\n"; 856 } 857 if (mark_bitmap != nullptr) { 858 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 859 } 860 } 861 for (const auto& space : discontinuous_spaces_) { 862 stream << space << " " << *space << "\n"; 863 } 864} 865 866void Heap::VerifyObjectBody(const mirror::Object* obj) { 867 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 868 // Ignore early dawn of the universe verifications. 869 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 870 return; 871 } 872 const byte* raw_addr = reinterpret_cast<const byte*>(obj) + 873 mirror::Object::ClassOffset().Int32Value(); 874 const mirror::Class* c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 875 if (UNLIKELY(c == NULL)) { 876 LOG(FATAL) << "Null class in object: " << obj; 877 } else if (UNLIKELY(!IsAligned<kObjectAlignment>(c))) { 878 LOG(FATAL) << "Class isn't aligned: " << c << " in object: " << obj; 879 } 880 // Check obj.getClass().getClass() == obj.getClass().getClass().getClass() 881 // Note: we don't use the accessors here as they have internal sanity checks 882 // that we don't want to run 883 raw_addr = reinterpret_cast<const byte*>(c) + mirror::Object::ClassOffset().Int32Value(); 884 const mirror::Class* c_c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 885 raw_addr = reinterpret_cast<const byte*>(c_c) + mirror::Object::ClassOffset().Int32Value(); 886 const mirror::Class* c_c_c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 887 CHECK_EQ(c_c, c_c_c); 888 889 if (verify_object_mode_ > kVerifyAllFast) { 890 // TODO: the bitmap tests below are racy if VerifyObjectBody is called without the 891 // heap_bitmap_lock_. 892 if (!IsLiveObjectLocked(obj)) { 893 DumpSpaces(); 894 LOG(FATAL) << "Object is dead: " << obj; 895 } 896 if (!IsLiveObjectLocked(c)) { 897 LOG(FATAL) << "Class of object is dead: " << c << " in object: " << obj; 898 } 899 } 900} 901 902void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 903 DCHECK(obj != NULL); 904 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 905} 906 907void Heap::VerifyHeap() { 908 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 909 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 910} 911 912void Heap::RecordFree(int64_t freed_objects, int64_t freed_bytes) { 913 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 914 num_bytes_allocated_.FetchAndSub(freed_bytes); 915 if (Runtime::Current()->HasStatsEnabled()) { 916 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 917 thread_stats->freed_objects += freed_objects; 918 thread_stats->freed_bytes += freed_bytes; 919 // TODO: Do this concurrently. 920 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 921 global_stats->freed_objects += freed_objects; 922 global_stats->freed_bytes += freed_bytes; 923 } 924} 925 926mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 927 size_t alloc_size, size_t* bytes_allocated, 928 mirror::Class** klass) { 929 mirror::Object* ptr = nullptr; 930 bool was_default_allocator = allocator == GetCurrentAllocator(); 931 DCHECK(klass != nullptr); 932 SirtRef<mirror::Class> sirt_klass(self, *klass); 933 // The allocation failed. If the GC is running, block until it completes, and then retry the 934 // allocation. 935 collector::GcType last_gc = WaitForGcToComplete(self); 936 if (last_gc != collector::kGcTypeNone) { 937 // If we were the default allocator but the allocator changed while we were suspended, 938 // abort the allocation. 939 if (was_default_allocator && allocator != GetCurrentAllocator()) { 940 *klass = sirt_klass.get(); 941 return nullptr; 942 } 943 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 944 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 945 } 946 947 // Loop through our different Gc types and try to Gc until we get enough free memory. 948 for (collector::GcType gc_type : gc_plan_) { 949 if (ptr != nullptr) { 950 break; 951 } 952 // Attempt to run the collector, if we succeed, re-try the allocation. 953 bool gc_ran = 954 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 955 if (was_default_allocator && allocator != GetCurrentAllocator()) { 956 *klass = sirt_klass.get(); 957 return nullptr; 958 } 959 if (gc_ran) { 960 // Did we free sufficient memory for the allocation to succeed? 961 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 962 } 963 } 964 // Allocations have failed after GCs; this is an exceptional state. 965 if (ptr == nullptr) { 966 // Try harder, growing the heap if necessary. 967 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 968 } 969 if (ptr == nullptr) { 970 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 971 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 972 // VM spec requires that all SoftReferences have been collected and cleared before throwing 973 // OOME. 974 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 975 << " allocation"; 976 // TODO: Run finalization, but this may cause more allocations to occur. 977 // We don't need a WaitForGcToComplete here either. 978 DCHECK(!gc_plan_.empty()); 979 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 980 if (was_default_allocator && allocator != GetCurrentAllocator()) { 981 *klass = sirt_klass.get(); 982 return nullptr; 983 } 984 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 985 if (ptr == nullptr) { 986 ThrowOutOfMemoryError(self, alloc_size, false); 987 } 988 } 989 *klass = sirt_klass.get(); 990 return ptr; 991} 992 993void Heap::SetTargetHeapUtilization(float target) { 994 DCHECK_GT(target, 0.0f); // asserted in Java code 995 DCHECK_LT(target, 1.0f); 996 target_utilization_ = target; 997} 998 999size_t Heap::GetObjectsAllocated() const { 1000 size_t total = 0; 1001 for (space::AllocSpace* space : alloc_spaces_) { 1002 total += space->GetObjectsAllocated(); 1003 } 1004 return total; 1005} 1006 1007size_t Heap::GetObjectsAllocatedEver() const { 1008 return GetObjectsFreedEver() + GetObjectsAllocated(); 1009} 1010 1011size_t Heap::GetBytesAllocatedEver() const { 1012 return GetBytesFreedEver() + GetBytesAllocated(); 1013} 1014 1015class InstanceCounter { 1016 public: 1017 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1018 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1019 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1020 } 1021 1022 void operator()(const mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1023 for (size_t i = 0; i < classes_.size(); ++i) { 1024 const mirror::Class* instance_class = o->GetClass(); 1025 if (use_is_assignable_from_) { 1026 if (instance_class != NULL && classes_[i]->IsAssignableFrom(instance_class)) { 1027 ++counts_[i]; 1028 } 1029 } else { 1030 if (instance_class == classes_[i]) { 1031 ++counts_[i]; 1032 } 1033 } 1034 } 1035 } 1036 1037 private: 1038 const std::vector<mirror::Class*>& classes_; 1039 bool use_is_assignable_from_; 1040 uint64_t* const counts_; 1041 1042 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1043}; 1044 1045void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1046 uint64_t* counts) { 1047 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1048 // is empty, so the live bitmap is the only place we need to look. 1049 Thread* self = Thread::Current(); 1050 self->TransitionFromRunnableToSuspended(kNative); 1051 CollectGarbage(false); 1052 self->TransitionFromSuspendedToRunnable(); 1053 1054 InstanceCounter counter(classes, use_is_assignable_from, counts); 1055 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1056 GetLiveBitmap()->Visit(counter); 1057} 1058 1059class InstanceCollector { 1060 public: 1061 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1062 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1063 : class_(c), max_count_(max_count), instances_(instances) { 1064 } 1065 1066 void operator()(const mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1067 const mirror::Class* instance_class = o->GetClass(); 1068 if (instance_class == class_) { 1069 if (max_count_ == 0 || instances_.size() < max_count_) { 1070 instances_.push_back(const_cast<mirror::Object*>(o)); 1071 } 1072 } 1073 } 1074 1075 private: 1076 mirror::Class* class_; 1077 uint32_t max_count_; 1078 std::vector<mirror::Object*>& instances_; 1079 1080 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1081}; 1082 1083void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1084 std::vector<mirror::Object*>& instances) { 1085 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1086 // is empty, so the live bitmap is the only place we need to look. 1087 Thread* self = Thread::Current(); 1088 self->TransitionFromRunnableToSuspended(kNative); 1089 CollectGarbage(false); 1090 self->TransitionFromSuspendedToRunnable(); 1091 1092 InstanceCollector collector(c, max_count, instances); 1093 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1094 GetLiveBitmap()->Visit(collector); 1095} 1096 1097class ReferringObjectsFinder { 1098 public: 1099 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1100 std::vector<mirror::Object*>& referring_objects) 1101 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1102 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1103 } 1104 1105 // For bitmap Visit. 1106 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1107 // annotalysis on visitors. 1108 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1109 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1110 } 1111 1112 // For MarkSweep::VisitObjectReferences. 1113 void operator()(mirror::Object* referrer, mirror::Object* object, 1114 const MemberOffset&, bool) const { 1115 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1116 referring_objects_.push_back(referrer); 1117 } 1118 } 1119 1120 private: 1121 mirror::Object* object_; 1122 uint32_t max_count_; 1123 std::vector<mirror::Object*>& referring_objects_; 1124 1125 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1126}; 1127 1128void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1129 std::vector<mirror::Object*>& referring_objects) { 1130 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1131 // is empty, so the live bitmap is the only place we need to look. 1132 Thread* self = Thread::Current(); 1133 self->TransitionFromRunnableToSuspended(kNative); 1134 CollectGarbage(false); 1135 self->TransitionFromSuspendedToRunnable(); 1136 1137 ReferringObjectsFinder finder(o, max_count, referring_objects); 1138 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1139 GetLiveBitmap()->Visit(finder); 1140} 1141 1142void Heap::CollectGarbage(bool clear_soft_references) { 1143 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1144 // last GC will not have necessarily been cleared. 1145 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1146} 1147 1148void Heap::TransitionCollector(CollectorType collector_type) { 1149 if (collector_type == collector_type_) { 1150 return; 1151 } 1152 uint64_t start_time = NanoTime(); 1153 int32_t before_size = GetTotalMemory(); 1154 int32_t before_allocated = num_bytes_allocated_.Load(); 1155 ThreadList* tl = Runtime::Current()->GetThreadList(); 1156 Thread* self = Thread::Current(); 1157 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1158 Locks::mutator_lock_->AssertNotHeld(self); 1159 // Busy wait until we can GC (StartGC can fail if we have a non-zero gc_disable_count_, this 1160 // rarely occurs however). 1161 while (!StartGC(self)) { 1162 usleep(100); 1163 } 1164 tl->SuspendAll(); 1165 switch (collector_type) { 1166 case kCollectorTypeSS: { 1167 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1168 CHECK(main_space_ != nullptr); 1169 Compact(temp_space_, main_space_); 1170 DCHECK(allocator_mem_map_.get() == nullptr); 1171 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1172 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1173 // RemoveSpace deletes the removed space. 1174 RemoveSpace(main_space_); 1175 break; 1176 } 1177 case kCollectorTypeMS: 1178 // Fall through. 1179 case kCollectorTypeCMS: { 1180 if (collector_type_ == kCollectorTypeSS) { 1181 // TODO: Use mem-map from temp space? 1182 MemMap* mem_map = allocator_mem_map_.release(); 1183 CHECK(mem_map != nullptr); 1184 size_t initial_size = kDefaultInitialSize; 1185 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1186 CHECK(main_space_ == nullptr); 1187 if (kUseRosAlloc) { 1188 main_space_ = 1189 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1190 initial_size, mem_map->Size(), 1191 mem_map->Size(), low_memory_mode_); 1192 } else { 1193 main_space_ = 1194 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1195 initial_size, mem_map->Size(), 1196 mem_map->Size()); 1197 } 1198 main_space_->SetFootprintLimit(main_space_->Capacity()); 1199 AddSpace(main_space_); 1200 Compact(main_space_, bump_pointer_space_); 1201 } 1202 break; 1203 } 1204 default: { 1205 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1206 break; 1207 } 1208 } 1209 ChangeCollector(collector_type); 1210 tl->ResumeAll(); 1211 // Can't call into java code with all threads suspended. 1212 EnqueueClearedReferences(); 1213 uint64_t duration = NanoTime() - start_time; 1214 GrowForUtilization(collector::kGcTypeFull, duration); 1215 FinishGC(self, collector::kGcTypeFull); 1216 int32_t after_size = GetTotalMemory(); 1217 int32_t delta_size = before_size - after_size; 1218 int32_t after_allocated = num_bytes_allocated_.Load(); 1219 int32_t delta_allocated = before_allocated - after_allocated; 1220 const std::string saved_bytes_str = 1221 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1222 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1223 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1224 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1225 << PrettySize(delta_size) << " saved"; 1226} 1227 1228void Heap::ChangeCollector(CollectorType collector_type) { 1229 // TODO: Only do this with all mutators suspended to avoid races. 1230 if (collector_type != collector_type_) { 1231 collector_type_ = collector_type; 1232 gc_plan_.clear(); 1233 switch (collector_type_) { 1234 case kCollectorTypeSS: { 1235 concurrent_gc_ = false; 1236 gc_plan_.push_back(collector::kGcTypeFull); 1237 if (use_tlab_) { 1238 ChangeAllocator(kAllocatorTypeTLAB); 1239 } else { 1240 ChangeAllocator(kAllocatorTypeBumpPointer); 1241 } 1242 break; 1243 } 1244 case kCollectorTypeMS: { 1245 concurrent_gc_ = false; 1246 gc_plan_.push_back(collector::kGcTypeSticky); 1247 gc_plan_.push_back(collector::kGcTypePartial); 1248 gc_plan_.push_back(collector::kGcTypeFull); 1249 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1250 break; 1251 } 1252 case kCollectorTypeCMS: { 1253 concurrent_gc_ = true; 1254 gc_plan_.push_back(collector::kGcTypeSticky); 1255 gc_plan_.push_back(collector::kGcTypePartial); 1256 gc_plan_.push_back(collector::kGcTypeFull); 1257 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1258 break; 1259 } 1260 default: { 1261 LOG(FATAL) << "Unimplemented"; 1262 } 1263 } 1264 if (concurrent_gc_) { 1265 concurrent_start_bytes_ = 1266 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1267 } else { 1268 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1269 } 1270 } 1271} 1272 1273static void MarkInBitmapCallback(mirror::Object* obj, void* arg) { 1274 reinterpret_cast<accounting::SpaceBitmap*>(arg)->Set(obj); 1275} 1276 1277// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1278class ZygoteCompactingCollector : public collector::SemiSpace { 1279 public: 1280 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector") { 1281 } 1282 1283 void BuildBins(space::ContinuousSpace* space) { 1284 bin_live_bitmap_ = space->GetLiveBitmap(); 1285 bin_mark_bitmap_ = space->GetMarkBitmap(); 1286 BinContext context; 1287 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1288 context.collector_ = this; 1289 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1290 // Note: This requires traversing the space in increasing order of object addresses. 1291 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1292 // Add the last bin which spans after the last object to the end of the space. 1293 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1294 } 1295 1296 private: 1297 struct BinContext { 1298 uintptr_t prev_; // The end of the previous object. 1299 ZygoteCompactingCollector* collector_; 1300 }; 1301 // Maps from bin sizes to locations. 1302 std::multimap<size_t, uintptr_t> bins_; 1303 // Live bitmap of the space which contains the bins. 1304 accounting::SpaceBitmap* bin_live_bitmap_; 1305 // Mark bitmap of the space which contains the bins. 1306 accounting::SpaceBitmap* bin_mark_bitmap_; 1307 1308 static void Callback(mirror::Object* obj, void* arg) 1309 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1310 DCHECK(arg != nullptr); 1311 BinContext* context = reinterpret_cast<BinContext*>(arg); 1312 ZygoteCompactingCollector* collector = context->collector_; 1313 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1314 size_t bin_size = object_addr - context->prev_; 1315 // Add the bin consisting of the end of the previous object to the start of the current object. 1316 collector->AddBin(bin_size, context->prev_); 1317 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1318 } 1319 1320 void AddBin(size_t size, uintptr_t position) { 1321 if (size != 0) { 1322 bins_.insert(std::make_pair(size, position)); 1323 } 1324 } 1325 1326 virtual bool ShouldSweepSpace(space::MallocSpace* space) const { 1327 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1328 // allocator. 1329 return false; 1330 } 1331 1332 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1333 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1334 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1335 mirror::Object* forward_address; 1336 // Find the smallest bin which we can move obj in. 1337 auto it = bins_.lower_bound(object_size); 1338 if (it == bins_.end()) { 1339 // No available space in the bins, place it in the target space instead (grows the zygote 1340 // space). 1341 size_t bytes_allocated; 1342 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated); 1343 if (to_space_live_bitmap_ != nullptr) { 1344 to_space_live_bitmap_->Set(forward_address); 1345 } 1346 } else { 1347 size_t size = it->first; 1348 uintptr_t pos = it->second; 1349 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1350 forward_address = reinterpret_cast<mirror::Object*>(pos); 1351 // Set the live and mark bits so that sweeping system weaks works properly. 1352 bin_live_bitmap_->Set(forward_address); 1353 bin_mark_bitmap_->Set(forward_address); 1354 DCHECK_GE(size, object_size); 1355 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1356 } 1357 // Copy the object over to its new location. 1358 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1359 return forward_address; 1360 } 1361}; 1362 1363void Heap::PreZygoteFork() { 1364 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1365 Thread* self = Thread::Current(); 1366 MutexLock mu(self, zygote_creation_lock_); 1367 // Try to see if we have any Zygote spaces. 1368 if (have_zygote_space_) { 1369 return; 1370 } 1371 VLOG(heap) << "Starting PreZygoteFork"; 1372 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1373 // Trim the pages at the end of the non moving space. 1374 non_moving_space_->Trim(); 1375 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1376 // Change the collector to the post zygote one. 1377 ChangeCollector(post_zygote_collector_type_); 1378 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1379 if (semi_space_collector_ != nullptr) { 1380 ZygoteCompactingCollector zygote_collector(this); 1381 zygote_collector.BuildBins(non_moving_space_); 1382 // Create a new bump pointer space which we will compact into. 1383 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1384 non_moving_space_->Limit()); 1385 // Compact the bump pointer space to a new zygote bump pointer space. 1386 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1387 zygote_collector.SetFromSpace(bump_pointer_space_); 1388 zygote_collector.SetToSpace(&target_space); 1389 zygote_collector.Run(false); 1390 CHECK(temp_space_->IsEmpty()); 1391 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1392 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1393 // Update the end and write out image. 1394 non_moving_space_->SetEnd(target_space.End()); 1395 non_moving_space_->SetLimit(target_space.Limit()); 1396 accounting::SpaceBitmap* bitmap = non_moving_space_->GetLiveBitmap(); 1397 // Record the allocations in the bitmap. 1398 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1399 target_space.Walk(MarkInBitmapCallback, bitmap); 1400 } 1401 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1402 // the remaining available heap memory. 1403 space::MallocSpace* zygote_space = non_moving_space_; 1404 main_space_ = non_moving_space_->CreateZygoteSpace("alloc space", low_memory_mode_); 1405 if (main_space_->IsRosAllocSpace()) { 1406 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1407 } else if (main_space_->IsDlMallocSpace()) { 1408 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1409 } 1410 main_space_->SetFootprintLimit(main_space_->Capacity()); 1411 // Change the GC retention policy of the zygote space to only collect when full. 1412 zygote_space->SetGcRetentionPolicy(space::kGcRetentionPolicyFullCollect); 1413 AddSpace(main_space_); 1414 have_zygote_space_ = true; 1415 zygote_space->InvalidateAllocator(); 1416 // Create the zygote space mod union table. 1417 accounting::ModUnionTable* mod_union_table = 1418 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1419 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1420 AddModUnionTable(mod_union_table); 1421 // Reset the cumulative loggers since we now have a few additional timing phases. 1422 for (const auto& collector : garbage_collectors_) { 1423 collector->ResetCumulativeStatistics(); 1424 } 1425 // Can't use RosAlloc for non moving space due to thread local buffers. 1426 // TODO: Non limited space for non-movable objects? 1427 space::MallocSpace* new_non_moving_space 1428 = space::DlMallocSpace::Create("Non moving dlmalloc space", 2 * MB, 64 * MB, 64 * MB, 1429 nullptr); 1430 AddSpace(new_non_moving_space, false); 1431 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1432 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1433 non_moving_space_ = new_non_moving_space; 1434} 1435 1436void Heap::FlushAllocStack() { 1437 MarkAllocStackAsLive(allocation_stack_.get()); 1438 allocation_stack_->Reset(); 1439} 1440 1441void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1442 accounting::SpaceBitmap* bitmap2, 1443 accounting::ObjectSet* large_objects, 1444 accounting::ObjectStack* stack) { 1445 DCHECK(bitmap1 != nullptr); 1446 DCHECK(bitmap2 != nullptr); 1447 mirror::Object** limit = stack->End(); 1448 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1449 const mirror::Object* obj = *it; 1450 DCHECK(obj != nullptr); 1451 if (bitmap1->HasAddress(obj)) { 1452 bitmap1->Set(obj); 1453 } else if (bitmap2->HasAddress(obj)) { 1454 bitmap2->Set(obj); 1455 } else { 1456 large_objects->Set(obj); 1457 } 1458 } 1459} 1460 1461const char* PrettyCause(GcCause cause) { 1462 switch (cause) { 1463 case kGcCauseForAlloc: return "Alloc"; 1464 case kGcCauseBackground: return "Background"; 1465 case kGcCauseExplicit: return "Explicit"; 1466 default: 1467 LOG(FATAL) << "Unreachable"; 1468 } 1469 return ""; 1470} 1471 1472void Heap::SwapSemiSpaces() { 1473 // Swap the spaces so we allocate into the space which we just evacuated. 1474 std::swap(bump_pointer_space_, temp_space_); 1475} 1476 1477void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1478 space::ContinuousMemMapAllocSpace* source_space) { 1479 CHECK(kMovingCollector); 1480 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1481 if (target_space != source_space) { 1482 semi_space_collector_->SetFromSpace(source_space); 1483 semi_space_collector_->SetToSpace(target_space); 1484 semi_space_collector_->Run(false); 1485 } 1486} 1487 1488collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1489 bool clear_soft_references) { 1490 Thread* self = Thread::Current(); 1491 Runtime* runtime = Runtime::Current(); 1492 // If the heap can't run the GC, silently fail and return that no GC was run. 1493 switch (gc_type) { 1494 case collector::kGcTypePartial: { 1495 if (!have_zygote_space_) { 1496 return collector::kGcTypeNone; 1497 } 1498 break; 1499 } 1500 default: { 1501 // Other GC types don't have any special cases which makes them not runnable. The main case 1502 // here is full GC. 1503 } 1504 } 1505 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1506 Locks::mutator_lock_->AssertNotHeld(self); 1507 if (self->IsHandlingStackOverflow()) { 1508 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1509 } 1510 gc_complete_lock_->AssertNotHeld(self); 1511 if (!StartGC(self)) { 1512 return collector::kGcTypeNone; 1513 } 1514 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1515 ++runtime->GetStats()->gc_for_alloc_count; 1516 ++self->GetStats()->gc_for_alloc_count; 1517 } 1518 uint64_t gc_start_time_ns = NanoTime(); 1519 uint64_t gc_start_size = GetBytesAllocated(); 1520 // Approximate allocation rate in bytes / second. 1521 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1522 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1523 if (LIKELY(ms_delta != 0)) { 1524 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1525 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1526 } 1527 1528 DCHECK_LT(gc_type, collector::kGcTypeMax); 1529 DCHECK_NE(gc_type, collector::kGcTypeNone); 1530 1531 collector::GarbageCollector* collector = nullptr; 1532 // TODO: Clean this up. 1533 if (collector_type_ == kCollectorTypeSS) { 1534 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1535 current_allocator_ == kAllocatorTypeTLAB); 1536 gc_type = semi_space_collector_->GetGcType(); 1537 CHECK(temp_space_->IsEmpty()); 1538 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1539 semi_space_collector_->SetToSpace(temp_space_); 1540 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1541 collector = semi_space_collector_; 1542 gc_type = collector::kGcTypeFull; 1543 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1544 current_allocator_ == kAllocatorTypeDlMalloc) { 1545 for (const auto& cur_collector : garbage_collectors_) { 1546 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1547 cur_collector->GetGcType() == gc_type) { 1548 collector = cur_collector; 1549 break; 1550 } 1551 } 1552 } else { 1553 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1554 } 1555 CHECK(collector != nullptr) 1556 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1557 << " and type=" << gc_type; 1558 1559 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1560 1561 collector->Run(clear_soft_references); 1562 total_objects_freed_ever_ += collector->GetFreedObjects(); 1563 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1564 1565 // Enqueue cleared references. 1566 Locks::mutator_lock_->AssertNotHeld(self); 1567 EnqueueClearedReferences(); 1568 1569 // Grow the heap so that we know when to perform the next GC. 1570 GrowForUtilization(gc_type, collector->GetDurationNs()); 1571 1572 if (CareAboutPauseTimes()) { 1573 const size_t duration = collector->GetDurationNs(); 1574 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1575 // GC for alloc pauses the allocating thread, so consider it as a pause. 1576 bool was_slow = duration > long_gc_log_threshold_ || 1577 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1578 if (!was_slow) { 1579 for (uint64_t pause : pauses) { 1580 was_slow = was_slow || pause > long_pause_log_threshold_; 1581 } 1582 } 1583 if (was_slow) { 1584 const size_t percent_free = GetPercentFree(); 1585 const size_t current_heap_size = GetBytesAllocated(); 1586 const size_t total_memory = GetTotalMemory(); 1587 std::ostringstream pause_string; 1588 for (size_t i = 0; i < pauses.size(); ++i) { 1589 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1590 << ((i != pauses.size() - 1) ? ", " : ""); 1591 } 1592 LOG(INFO) << gc_cause << " " << collector->GetName() 1593 << " GC freed " << collector->GetFreedObjects() << "(" 1594 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1595 << collector->GetFreedLargeObjects() << "(" 1596 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1597 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1598 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1599 << " total " << PrettyDuration((duration / 1000) * 1000); 1600 if (VLOG_IS_ON(heap)) { 1601 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1602 } 1603 } 1604 } 1605 FinishGC(self, gc_type); 1606 ATRACE_END(); 1607 1608 // Inform DDMS that a GC completed. 1609 Dbg::GcDidFinish(); 1610 return gc_type; 1611} 1612 1613bool Heap::StartGC(Thread* self) { 1614 MutexLock mu(self, *gc_complete_lock_); 1615 // Ensure there is only one GC at a time. 1616 WaitForGcToCompleteLocked(self); 1617 // TODO: if another thread beat this one to do the GC, perhaps we should just return here? 1618 // Not doing at the moment to ensure soft references are cleared. 1619 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1620 if (gc_disable_count_ != 0) { 1621 LOG(WARNING) << "Skipping GC due to disable count " << gc_disable_count_; 1622 return false; 1623 } 1624 is_gc_running_ = true; 1625 return true; 1626} 1627 1628void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1629 MutexLock mu(self, *gc_complete_lock_); 1630 is_gc_running_ = false; 1631 last_gc_type_ = gc_type; 1632 // Wake anyone who may have been waiting for the GC to complete. 1633 gc_complete_cond_->Broadcast(self); 1634} 1635 1636static mirror::Object* RootMatchesObjectVisitor(mirror::Object* root, void* arg) { 1637 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1638 if (root == obj) { 1639 LOG(INFO) << "Object " << obj << " is a root"; 1640 } 1641 return root; 1642} 1643 1644class ScanVisitor { 1645 public: 1646 void operator()(const mirror::Object* obj) const { 1647 LOG(ERROR) << "Would have rescanned object " << obj; 1648 } 1649}; 1650 1651// Verify a reference from an object. 1652class VerifyReferenceVisitor { 1653 public: 1654 explicit VerifyReferenceVisitor(Heap* heap) 1655 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1656 : heap_(heap), failed_(false) {} 1657 1658 bool Failed() const { 1659 return failed_; 1660 } 1661 1662 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1663 // analysis on visitors. 1664 void operator()(const mirror::Object* obj, const mirror::Object* ref, 1665 const MemberOffset& offset, bool /* is_static */) const 1666 NO_THREAD_SAFETY_ANALYSIS { 1667 // Verify that the reference is live. 1668 if (UNLIKELY(ref != NULL && !IsLive(ref))) { 1669 accounting::CardTable* card_table = heap_->GetCardTable(); 1670 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1671 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1672 if (!failed_) { 1673 // Print message on only on first failure to prevent spam. 1674 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1675 failed_ = true; 1676 } 1677 if (obj != nullptr) { 1678 byte* card_addr = card_table->CardFromAddr(obj); 1679 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1680 << offset << "\n card value = " << static_cast<int>(*card_addr); 1681 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1682 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1683 } else { 1684 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1685 } 1686 1687 // Attmept to find the class inside of the recently freed objects. 1688 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1689 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1690 space::MallocSpace* space = ref_space->AsMallocSpace(); 1691 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1692 if (ref_class != nullptr) { 1693 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1694 << PrettyClass(ref_class); 1695 } else { 1696 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1697 } 1698 } 1699 1700 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1701 ref->GetClass()->IsClass()) { 1702 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1703 } else { 1704 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1705 << ") is not a valid heap address"; 1706 } 1707 1708 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1709 void* cover_begin = card_table->AddrFromCard(card_addr); 1710 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1711 accounting::CardTable::kCardSize); 1712 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1713 << "-" << cover_end; 1714 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1715 1716 // Print out how the object is live. 1717 if (bitmap != NULL && bitmap->Test(obj)) { 1718 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1719 } 1720 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1721 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1722 } 1723 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1724 LOG(ERROR) << "Object " << obj << " found in live stack"; 1725 } 1726 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1727 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1728 } 1729 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1730 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1731 } 1732 // Attempt to see if the card table missed the reference. 1733 ScanVisitor scan_visitor; 1734 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1735 card_table->Scan(bitmap, byte_cover_begin, 1736 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1737 1738 // Search to see if any of the roots reference our object. 1739 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1740 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1741 1742 // Search to see if any of the roots reference our reference. 1743 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1744 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1745 } else { 1746 LOG(ERROR) << "Root references dead object " << ref << "\nRef type " << PrettyTypeOf(ref); 1747 } 1748 } 1749 } 1750 1751 bool IsLive(const mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1752 return heap_->IsLiveObjectLocked(obj, true, false, true); 1753 } 1754 1755 static mirror::Object* VerifyRoots(mirror::Object* root, void* arg) { 1756 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1757 (*visitor)(nullptr, root, MemberOffset(0), true); 1758 return root; 1759 } 1760 1761 private: 1762 Heap* const heap_; 1763 mutable bool failed_; 1764}; 1765 1766// Verify all references within an object, for use with HeapBitmap::Visit. 1767class VerifyObjectVisitor { 1768 public: 1769 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1770 1771 void operator()(mirror::Object* obj) const 1772 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1773 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1774 // be live or else how did we find it in the live bitmap? 1775 VerifyReferenceVisitor visitor(heap_); 1776 // The class doesn't count as a reference but we should verify it anyways. 1777 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1778 if (obj->GetClass()->IsReferenceClass()) { 1779 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1780 } 1781 failed_ = failed_ || visitor.Failed(); 1782 } 1783 1784 static void VisitCallback(mirror::Object* obj, void* arg) 1785 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1786 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1787 visitor->operator()(obj); 1788 } 1789 1790 bool Failed() const { 1791 return failed_; 1792 } 1793 1794 private: 1795 Heap* const heap_; 1796 mutable bool failed_; 1797}; 1798 1799// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1800bool Heap::VerifyHeapReferences() { 1801 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1802 // Lets sort our allocation stacks so that we can efficiently binary search them. 1803 allocation_stack_->Sort(); 1804 live_stack_->Sort(); 1805 VerifyObjectVisitor visitor(this); 1806 // Verify objects in the allocation stack since these will be objects which were: 1807 // 1. Allocated prior to the GC (pre GC verification). 1808 // 2. Allocated during the GC (pre sweep GC verification). 1809 // We don't want to verify the objects in the live stack since they themselves may be 1810 // pointing to dead objects if they are not reachable. 1811 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1812 // Verify the roots: 1813 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1814 if (visitor.Failed()) { 1815 // Dump mod-union tables. 1816 for (const auto& table_pair : mod_union_tables_) { 1817 accounting::ModUnionTable* mod_union_table = table_pair.second; 1818 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1819 } 1820 DumpSpaces(); 1821 return false; 1822 } 1823 return true; 1824} 1825 1826class VerifyReferenceCardVisitor { 1827 public: 1828 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1829 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1830 Locks::heap_bitmap_lock_) 1831 : heap_(heap), failed_(failed) { 1832 } 1833 1834 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1835 // annotalysis on visitors. 1836 void operator()(const mirror::Object* obj, const mirror::Object* ref, const MemberOffset& offset, 1837 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1838 // Filter out class references since changing an object's class does not mark the card as dirty. 1839 // Also handles large objects, since the only reference they hold is a class reference. 1840 if (ref != NULL && !ref->IsClass()) { 1841 accounting::CardTable* card_table = heap_->GetCardTable(); 1842 // If the object is not dirty and it is referencing something in the live stack other than 1843 // class, then it must be on a dirty card. 1844 if (!card_table->AddrIsInCardTable(obj)) { 1845 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1846 *failed_ = true; 1847 } else if (!card_table->IsDirty(obj)) { 1848 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1849 // kCardDirty - 1 if it didnt get touched since we aged it. 1850 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1851 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1852 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1853 LOG(ERROR) << "Object " << obj << " found in live stack"; 1854 } 1855 if (heap_->GetLiveBitmap()->Test(obj)) { 1856 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1857 } 1858 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1859 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1860 1861 // Print which field of the object is dead. 1862 if (!obj->IsObjectArray()) { 1863 const mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1864 CHECK(klass != NULL); 1865 const mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1866 : klass->GetIFields(); 1867 CHECK(fields != NULL); 1868 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1869 const mirror::ArtField* cur = fields->Get(i); 1870 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1871 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1872 << PrettyField(cur); 1873 break; 1874 } 1875 } 1876 } else { 1877 const mirror::ObjectArray<mirror::Object>* object_array = 1878 obj->AsObjectArray<mirror::Object>(); 1879 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1880 if (object_array->Get(i) == ref) { 1881 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1882 } 1883 } 1884 } 1885 1886 *failed_ = true; 1887 } 1888 } 1889 } 1890 } 1891 1892 private: 1893 Heap* const heap_; 1894 bool* const failed_; 1895}; 1896 1897class VerifyLiveStackReferences { 1898 public: 1899 explicit VerifyLiveStackReferences(Heap* heap) 1900 : heap_(heap), 1901 failed_(false) {} 1902 1903 void operator()(mirror::Object* obj) const 1904 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1905 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1906 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1907 } 1908 1909 bool Failed() const { 1910 return failed_; 1911 } 1912 1913 private: 1914 Heap* const heap_; 1915 bool failed_; 1916}; 1917 1918bool Heap::VerifyMissingCardMarks() { 1919 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1920 1921 // We need to sort the live stack since we binary search it. 1922 live_stack_->Sort(); 1923 VerifyLiveStackReferences visitor(this); 1924 GetLiveBitmap()->Visit(visitor); 1925 1926 // We can verify objects in the live stack since none of these should reference dead objects. 1927 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 1928 visitor(*it); 1929 } 1930 1931 if (visitor.Failed()) { 1932 DumpSpaces(); 1933 return false; 1934 } 1935 return true; 1936} 1937 1938void Heap::SwapStacks() { 1939 allocation_stack_.swap(live_stack_); 1940} 1941 1942accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 1943 auto it = mod_union_tables_.find(space); 1944 if (it == mod_union_tables_.end()) { 1945 return nullptr; 1946 } 1947 return it->second; 1948} 1949 1950void Heap::ProcessCards(TimingLogger& timings) { 1951 // Clear cards and keep track of cards cleared in the mod-union table. 1952 for (const auto& space : continuous_spaces_) { 1953 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 1954 if (table != nullptr) { 1955 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 1956 "ImageModUnionClearCards"; 1957 TimingLogger::ScopedSplit split(name, &timings); 1958 table->ClearCards(); 1959 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 1960 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 1961 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 1962 // were dirty before the GC started. 1963 // TODO: Don't need to use atomic. 1964 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 1965 // roots and then we scan / update mod union tables after. We will always scan either card.// 1966 // If we end up with the non aged card, we scan it it in the pause. 1967 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 1968 } 1969 } 1970} 1971 1972static mirror::Object* IdentityCallback(mirror::Object* obj, void*) { 1973 return obj; 1974} 1975 1976void Heap::PreGcVerification(collector::GarbageCollector* gc) { 1977 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 1978 Thread* self = Thread::Current(); 1979 1980 if (verify_pre_gc_heap_) { 1981 thread_list->SuspendAll(); 1982 { 1983 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1984 if (!VerifyHeapReferences()) { 1985 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 1986 } 1987 } 1988 thread_list->ResumeAll(); 1989 } 1990 1991 // Check that all objects which reference things in the live stack are on dirty cards. 1992 if (verify_missing_card_marks_) { 1993 thread_list->SuspendAll(); 1994 { 1995 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1996 SwapStacks(); 1997 // Sort the live stack so that we can quickly binary search it later. 1998 if (!VerifyMissingCardMarks()) { 1999 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2000 } 2001 SwapStacks(); 2002 } 2003 thread_list->ResumeAll(); 2004 } 2005 2006 if (verify_mod_union_table_) { 2007 thread_list->SuspendAll(); 2008 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2009 for (const auto& table_pair : mod_union_tables_) { 2010 accounting::ModUnionTable* mod_union_table = table_pair.second; 2011 mod_union_table->UpdateAndMarkReferences(IdentityCallback, nullptr); 2012 mod_union_table->Verify(); 2013 } 2014 thread_list->ResumeAll(); 2015 } 2016} 2017 2018void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2019 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2020 // reachable objects. 2021 if (verify_post_gc_heap_) { 2022 Thread* self = Thread::Current(); 2023 CHECK_NE(self->GetState(), kRunnable); 2024 { 2025 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2026 // Swapping bound bitmaps does nothing. 2027 gc->SwapBitmaps(); 2028 if (!VerifyHeapReferences()) { 2029 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2030 } 2031 gc->SwapBitmaps(); 2032 } 2033 } 2034} 2035 2036void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2037 if (verify_system_weaks_) { 2038 Thread* self = Thread::Current(); 2039 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2040 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2041 mark_sweep->VerifySystemWeaks(); 2042 } 2043} 2044 2045collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2046 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2047 MutexLock mu(self, *gc_complete_lock_); 2048 return WaitForGcToCompleteLocked(self); 2049} 2050 2051collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2052 collector::GcType last_gc_type = collector::kGcTypeNone; 2053 uint64_t wait_start = NanoTime(); 2054 while (is_gc_running_) { 2055 ATRACE_BEGIN("GC: Wait For Completion"); 2056 // We must wait, change thread state then sleep on gc_complete_cond_; 2057 gc_complete_cond_->Wait(self); 2058 last_gc_type = last_gc_type_; 2059 ATRACE_END(); 2060 } 2061 uint64_t wait_time = NanoTime() - wait_start; 2062 total_wait_time_ += wait_time; 2063 if (wait_time > long_pause_log_threshold_) { 2064 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2065 } 2066 return last_gc_type; 2067} 2068 2069void Heap::DumpForSigQuit(std::ostream& os) { 2070 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2071 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2072 DumpGcPerformanceInfo(os); 2073} 2074 2075size_t Heap::GetPercentFree() { 2076 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2077} 2078 2079void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2080 if (max_allowed_footprint > GetMaxMemory()) { 2081 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2082 << PrettySize(GetMaxMemory()); 2083 max_allowed_footprint = GetMaxMemory(); 2084 } 2085 max_allowed_footprint_ = max_allowed_footprint; 2086} 2087 2088bool Heap::IsMovableObject(const mirror::Object* obj) const { 2089 if (kMovingCollector) { 2090 DCHECK(!IsInTempSpace(obj)); 2091 if (bump_pointer_space_->HasAddress(obj)) { 2092 return true; 2093 } 2094 if (main_space_ != nullptr && main_space_->HasAddress(obj)) { 2095 return true; 2096 } 2097 } 2098 return false; 2099} 2100 2101bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2102 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2103 return true; 2104 } 2105 return false; 2106} 2107 2108void Heap::UpdateMaxNativeFootprint() { 2109 size_t native_size = native_bytes_allocated_; 2110 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2111 size_t target_size = native_size / GetTargetHeapUtilization(); 2112 if (target_size > native_size + max_free_) { 2113 target_size = native_size + max_free_; 2114 } else if (target_size < native_size + min_free_) { 2115 target_size = native_size + min_free_; 2116 } 2117 native_footprint_gc_watermark_ = target_size; 2118 native_footprint_limit_ = 2 * target_size - native_size; 2119} 2120 2121void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2122 // We know what our utilization is at this moment. 2123 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2124 const size_t bytes_allocated = GetBytesAllocated(); 2125 last_gc_size_ = bytes_allocated; 2126 last_gc_time_ns_ = NanoTime(); 2127 size_t target_size; 2128 if (gc_type != collector::kGcTypeSticky) { 2129 // Grow the heap for non sticky GC. 2130 target_size = bytes_allocated / GetTargetHeapUtilization(); 2131 if (target_size > bytes_allocated + max_free_) { 2132 target_size = bytes_allocated + max_free_; 2133 } else if (target_size < bytes_allocated + min_free_) { 2134 target_size = bytes_allocated + min_free_; 2135 } 2136 native_need_to_run_finalization_ = true; 2137 next_gc_type_ = collector::kGcTypeSticky; 2138 } else { 2139 // Based on how close the current heap size is to the target size, decide 2140 // whether or not to do a partial or sticky GC next. 2141 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2142 next_gc_type_ = collector::kGcTypeSticky; 2143 } else { 2144 next_gc_type_ = collector::kGcTypePartial; 2145 } 2146 // If we have freed enough memory, shrink the heap back down. 2147 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2148 target_size = bytes_allocated + max_free_; 2149 } else { 2150 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2151 } 2152 } 2153 if (!ignore_max_footprint_) { 2154 SetIdealFootprint(target_size); 2155 if (concurrent_gc_) { 2156 // Calculate when to perform the next ConcurrentGC. 2157 // Calculate the estimated GC duration. 2158 double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2159 // Estimate how many remaining bytes we will have when we need to start the next GC. 2160 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2161 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2162 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2163 // A never going to happen situation that from the estimated allocation rate we will exceed 2164 // the applications entire footprint with the given estimated allocation rate. Schedule 2165 // another GC straight away. 2166 concurrent_start_bytes_ = bytes_allocated; 2167 } else { 2168 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2169 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2170 // right away. 2171 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, 2172 bytes_allocated); 2173 } 2174 DCHECK_LE(concurrent_start_bytes_, max_allowed_footprint_); 2175 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2176 } 2177 } 2178} 2179 2180void Heap::ClearGrowthLimit() { 2181 growth_limit_ = capacity_; 2182 non_moving_space_->ClearGrowthLimit(); 2183} 2184 2185void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2186 MemberOffset reference_queue_offset, 2187 MemberOffset reference_queueNext_offset, 2188 MemberOffset reference_pendingNext_offset, 2189 MemberOffset finalizer_reference_zombie_offset) { 2190 reference_referent_offset_ = reference_referent_offset; 2191 reference_queue_offset_ = reference_queue_offset; 2192 reference_queueNext_offset_ = reference_queueNext_offset; 2193 reference_pendingNext_offset_ = reference_pendingNext_offset; 2194 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2195 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2196 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2197 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2198 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2199 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2200} 2201 2202void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2203 DCHECK(reference != NULL); 2204 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2205 reference->SetFieldObject(reference_referent_offset_, referent, true); 2206} 2207 2208mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2209 DCHECK(reference != NULL); 2210 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2211 return reference->GetFieldObject<mirror::Object*>(reference_referent_offset_, true); 2212} 2213 2214void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2215 ScopedObjectAccess soa(self); 2216 JValue result; 2217 ArgArray arg_array(NULL, 0); 2218 arg_array.Append(reinterpret_cast<uint32_t>(object)); 2219 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2220 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2221} 2222 2223void Heap::EnqueueClearedReferences() { 2224 if (!cleared_references_.IsEmpty()) { 2225 // When a runtime isn't started there are no reference queues to care about so ignore. 2226 if (LIKELY(Runtime::Current()->IsStarted())) { 2227 ScopedObjectAccess soa(Thread::Current()); 2228 JValue result; 2229 ArgArray arg_array(NULL, 0); 2230 arg_array.Append(reinterpret_cast<uint32_t>(cleared_references_.GetList())); 2231 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2232 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2233 } 2234 cleared_references_.Clear(); 2235 } 2236} 2237 2238void Heap::RequestConcurrentGC(Thread* self) { 2239 // Make sure that we can do a concurrent GC. 2240 Runtime* runtime = Runtime::Current(); 2241 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2242 self->IsHandlingStackOverflow()) { 2243 return; 2244 } 2245 // We already have a request pending, no reason to start more until we update 2246 // concurrent_start_bytes_. 2247 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2248 JNIEnv* env = self->GetJniEnv(); 2249 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2250 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2251 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2252 WellKnownClasses::java_lang_Daemons_requestGC); 2253 CHECK(!env->ExceptionCheck()); 2254} 2255 2256void Heap::ConcurrentGC(Thread* self) { 2257 if (Runtime::Current()->IsShuttingDown(self)) { 2258 return; 2259 } 2260 // Wait for any GCs currently running to finish. 2261 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2262 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2263 // instead. E.g. can't do partial, so do full instead. 2264 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2265 collector::kGcTypeNone) { 2266 for (collector::GcType gc_type : gc_plan_) { 2267 // Attempt to run the collector, if we succeed, we are done. 2268 if (gc_type > next_gc_type_ && 2269 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2270 break; 2271 } 2272 } 2273 } 2274 } 2275} 2276 2277void Heap::RequestHeapTrim() { 2278 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2279 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2280 // a space it will hold its lock and can become a cause of jank. 2281 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2282 // forking. 2283 2284 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2285 // because that only marks object heads, so a large array looks like lots of empty space. We 2286 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2287 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2288 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2289 // not how much use we're making of those pages. 2290 uint64_t ms_time = MilliTime(); 2291 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2292 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2293 return; 2294 } 2295 2296 Thread* self = Thread::Current(); 2297 Runtime* runtime = Runtime::Current(); 2298 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2299 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2300 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2301 // as we don't hold the lock while requesting the trim). 2302 return; 2303 } 2304 2305 last_trim_time_ms_ = ms_time; 2306 2307 // Trim only if we do not currently care about pause times. 2308 if (!CareAboutPauseTimes()) { 2309 JNIEnv* env = self->GetJniEnv(); 2310 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2311 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2312 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2313 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2314 CHECK(!env->ExceptionCheck()); 2315 } 2316} 2317 2318void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2319 if (rosalloc_space_ != nullptr) { 2320 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2321 } 2322 if (bump_pointer_space_ != nullptr) { 2323 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2324 } 2325} 2326 2327void Heap::RevokeAllThreadLocalBuffers() { 2328 if (rosalloc_space_ != nullptr) { 2329 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2330 } 2331 if (bump_pointer_space_ != nullptr) { 2332 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2333 } 2334} 2335 2336bool Heap::IsGCRequestPending() const { 2337 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2338} 2339 2340void Heap::RunFinalization(JNIEnv* env) { 2341 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2342 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2343 CHECK(WellKnownClasses::java_lang_System != nullptr); 2344 WellKnownClasses::java_lang_System_runFinalization = 2345 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2346 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2347 } 2348 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2349 WellKnownClasses::java_lang_System_runFinalization); 2350} 2351 2352void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2353 Thread* self = ThreadForEnv(env); 2354 if (native_need_to_run_finalization_) { 2355 RunFinalization(env); 2356 UpdateMaxNativeFootprint(); 2357 native_need_to_run_finalization_ = false; 2358 } 2359 // Total number of native bytes allocated. 2360 native_bytes_allocated_.FetchAndAdd(bytes); 2361 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2362 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2363 collector::kGcTypeFull; 2364 2365 // The second watermark is higher than the gc watermark. If you hit this it means you are 2366 // allocating native objects faster than the GC can keep up with. 2367 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2368 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2369 // Just finished a GC, attempt to run finalizers. 2370 RunFinalization(env); 2371 CHECK(!env->ExceptionCheck()); 2372 } 2373 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2374 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2375 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2376 RunFinalization(env); 2377 native_need_to_run_finalization_ = false; 2378 CHECK(!env->ExceptionCheck()); 2379 } 2380 // We have just run finalizers, update the native watermark since it is very likely that 2381 // finalizers released native managed allocations. 2382 UpdateMaxNativeFootprint(); 2383 } else if (!IsGCRequestPending()) { 2384 if (concurrent_gc_) { 2385 RequestConcurrentGC(self); 2386 } else { 2387 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2388 } 2389 } 2390 } 2391} 2392 2393void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2394 int expected_size, new_size; 2395 do { 2396 expected_size = native_bytes_allocated_.Load(); 2397 new_size = expected_size - bytes; 2398 if (UNLIKELY(new_size < 0)) { 2399 ScopedObjectAccess soa(env); 2400 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2401 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2402 "registered as allocated", bytes, expected_size).c_str()); 2403 break; 2404 } 2405 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2406} 2407 2408int64_t Heap::GetTotalMemory() const { 2409 int64_t ret = 0; 2410 for (const auto& space : continuous_spaces_) { 2411 // Currently don't include the image space. 2412 if (!space->IsImageSpace()) { 2413 ret += space->Size(); 2414 } 2415 } 2416 for (const auto& space : discontinuous_spaces_) { 2417 if (space->IsLargeObjectSpace()) { 2418 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2419 } 2420 } 2421 return ret; 2422} 2423 2424void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2425 DCHECK(mod_union_table != nullptr); 2426 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2427} 2428 2429} // namespace gc 2430} // namespace art 2431