heap.cc revision ef7d42fca18c16fbaf103822ad16f23246e2905d
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 "gc/space/zygote_space.h" 48#include "heap-inl.h" 49#include "image.h" 50#include "invoke_arg_array_builder.h" 51#include "mirror/art_field-inl.h" 52#include "mirror/class-inl.h" 53#include "mirror/object.h" 54#include "mirror/object-inl.h" 55#include "mirror/object_array-inl.h" 56#include "object_utils.h" 57#include "os.h" 58#include "runtime.h" 59#include "ScopedLocalRef.h" 60#include "scoped_thread_state_change.h" 61#include "sirt_ref.h" 62#include "thread_list.h" 63#include "UniquePtr.h" 64#include "well_known_classes.h" 65 66namespace art { 67 68extern void SetQuickAllocEntryPointsAllocator(gc::AllocatorType allocator); 69 70namespace gc { 71 72static constexpr bool kGCALotMode = false; 73static constexpr size_t kGcAlotInterval = KB; 74// Minimum amount of remaining bytes before a concurrent GC is triggered. 75static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 76static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 77 78Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 79 double target_utilization, size_t capacity, const std::string& image_file_name, 80 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 81 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 82 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 83 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 84 bool verify_post_gc_heap) 85 : non_moving_space_(nullptr), 86 rosalloc_space_(nullptr), 87 dlmalloc_space_(nullptr), 88 main_space_(nullptr), 89 concurrent_gc_(false), 90 collector_type_(kCollectorTypeNone), 91 post_zygote_collector_type_(post_zygote_collector_type), 92 background_collector_type_(background_collector_type), 93 parallel_gc_threads_(parallel_gc_threads), 94 conc_gc_threads_(conc_gc_threads), 95 low_memory_mode_(low_memory_mode), 96 long_pause_log_threshold_(long_pause_log_threshold), 97 long_gc_log_threshold_(long_gc_log_threshold), 98 ignore_max_footprint_(ignore_max_footprint), 99 have_zygote_space_(false), 100 soft_reference_queue_(this), 101 weak_reference_queue_(this), 102 finalizer_reference_queue_(this), 103 phantom_reference_queue_(this), 104 cleared_references_(this), 105 collector_type_running_(kCollectorTypeNone), 106 last_gc_type_(collector::kGcTypeNone), 107 next_gc_type_(collector::kGcTypePartial), 108 capacity_(capacity), 109 growth_limit_(growth_limit), 110 max_allowed_footprint_(initial_size), 111 native_footprint_gc_watermark_(initial_size), 112 native_footprint_limit_(2 * initial_size), 113 native_need_to_run_finalization_(false), 114 // Initially assume we perceive jank in case the process state is never updated. 115 process_state_(kProcessStateJankPerceptible), 116 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 117 total_bytes_freed_ever_(0), 118 total_objects_freed_ever_(0), 119 num_bytes_allocated_(0), 120 native_bytes_allocated_(0), 121 gc_memory_overhead_(0), 122 verify_missing_card_marks_(false), 123 verify_system_weaks_(false), 124 verify_pre_gc_heap_(verify_pre_gc_heap), 125 verify_post_gc_heap_(verify_post_gc_heap), 126 verify_mod_union_table_(false), 127 last_trim_time_ms_(0), 128 allocation_rate_(0), 129 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 130 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 131 * verification is enabled, we limit the size of allocation stacks to speed up their 132 * searching. 133 */ 134 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 135 : (kDesiredHeapVerification > kVerifyAllFast) ? KB : MB), 136 current_allocator_(kAllocatorTypeDlMalloc), 137 current_non_moving_allocator_(kAllocatorTypeNonMoving), 138 bump_pointer_space_(nullptr), 139 temp_space_(nullptr), 140 reference_referent_offset_(0), 141 reference_queue_offset_(0), 142 reference_queueNext_offset_(0), 143 reference_pendingNext_offset_(0), 144 finalizer_reference_zombie_offset_(0), 145 min_free_(min_free), 146 max_free_(max_free), 147 target_utilization_(target_utilization), 148 total_wait_time_(0), 149 total_allocation_time_(0), 150 verify_object_mode_(kHeapVerificationNotPermitted), 151 disable_moving_gc_count_(0), 152 running_on_valgrind_(RUNNING_ON_VALGRIND), 153 use_tlab_(use_tlab) { 154 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 155 LOG(INFO) << "Heap() entering"; 156 } 157 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 158 // entrypoints. 159 if (!Runtime::Current()->IsZygote() || !kMovingCollector) { 160 ChangeCollector(post_zygote_collector_type_); 161 } else { 162 // We are the zygote, use bump pointer allocation + semi space collector. 163 ChangeCollector(kCollectorTypeSS); 164 } 165 166 live_bitmap_.reset(new accounting::HeapBitmap(this)); 167 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 168 // Requested begin for the alloc space, to follow the mapped image and oat files 169 byte* requested_alloc_space_begin = nullptr; 170 if (!image_file_name.empty()) { 171 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 172 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 173 AddSpace(image_space); 174 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 175 // isn't going to get in the middle 176 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 177 CHECK_GT(oat_file_end_addr, image_space->End()); 178 if (oat_file_end_addr > requested_alloc_space_begin) { 179 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 180 } 181 } 182 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 183 space::MallocSpace* malloc_space; 184 if (kUseRosAlloc) { 185 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 186 requested_alloc_space_begin, low_memory_mode_); 187 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 188 } else { 189 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 190 requested_alloc_space_begin); 191 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 192 } 193 VLOG(heap) << "malloc_space : " << malloc_space; 194 if (kMovingCollector) { 195 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 196 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 197 // issues. 198 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 199 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 200 bump_pointer_space_size, nullptr); 201 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 202 AddSpace(bump_pointer_space_); 203 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 204 nullptr); 205 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 206 AddSpace(temp_space_); 207 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 208 VLOG(heap) << "temp_space : " << temp_space_; 209 } 210 non_moving_space_ = malloc_space; 211 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 212 AddSpace(malloc_space); 213 214 // Allocate the large object space. 215 constexpr bool kUseFreeListSpaceForLOS = false; 216 if (kUseFreeListSpaceForLOS) { 217 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 218 } else { 219 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 220 } 221 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 222 AddSpace(large_object_space_); 223 224 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 225 CHECK(!continuous_spaces_.empty()); 226 227 // Relies on the spaces being sorted. 228 byte* heap_begin = continuous_spaces_.front()->Begin(); 229 byte* heap_end = continuous_spaces_.back()->Limit(); 230 if (Runtime::Current()->IsZygote()) { 231 std::string error_str; 232 post_zygote_non_moving_space_mem_map_.reset( 233 MemMap::MapAnonymous("post zygote non-moving space", nullptr, 64 * MB, 234 PROT_READ | PROT_WRITE, true, &error_str)); 235 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 236 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 237 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 238 } 239 size_t heap_capacity = heap_end - heap_begin; 240 241 // Allocate the card table. 242 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 243 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 244 245 // Card cache for now since it makes it easier for us to update the references to the copying 246 // spaces. 247 accounting::ModUnionTable* mod_union_table = 248 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 249 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 250 AddModUnionTable(mod_union_table); 251 252 // TODO: Count objects in the image space here. 253 num_bytes_allocated_ = 0; 254 255 // Default mark stack size in bytes. 256 static const size_t default_mark_stack_size = 64 * KB; 257 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 258 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 259 max_allocation_stack_size_)); 260 live_stack_.reset(accounting::ObjectStack::Create("live stack", 261 max_allocation_stack_size_)); 262 263 // It's still too early to take a lock because there are no threads yet, but we can create locks 264 // now. We don't create it earlier to make it clear that you can't use locks during heap 265 // initialization. 266 gc_complete_lock_ = new Mutex("GC complete lock"); 267 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 268 *gc_complete_lock_)); 269 last_gc_time_ns_ = NanoTime(); 270 last_gc_size_ = GetBytesAllocated(); 271 272 if (ignore_max_footprint_) { 273 SetIdealFootprint(std::numeric_limits<size_t>::max()); 274 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 275 } 276 CHECK_NE(max_allowed_footprint_, 0U); 277 278 // Create our garbage collectors. 279 for (size_t i = 0; i < 2; ++i) { 280 const bool concurrent = i != 0; 281 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 282 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 283 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 284 } 285 if (kMovingCollector) { 286 // TODO: Clean this up. 287 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 288 semi_space_collector_ = new collector::SemiSpace(this, generational); 289 garbage_collectors_.push_back(semi_space_collector_); 290 } 291 292 if (running_on_valgrind_) { 293 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 294 } 295 296 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 297 LOG(INFO) << "Heap() exiting"; 298 } 299} 300 301void Heap::ChangeAllocator(AllocatorType allocator) { 302 // These two allocators are only used internally and don't have any entrypoints. 303 DCHECK_NE(allocator, kAllocatorTypeLOS); 304 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 305 if (current_allocator_ != allocator) { 306 current_allocator_ = allocator; 307 SetQuickAllocEntryPointsAllocator(current_allocator_); 308 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 309 } 310} 311 312bool Heap::IsCompilingBoot() const { 313 for (const auto& space : continuous_spaces_) { 314 if (space->IsImageSpace()) { 315 return false; 316 } else if (space->IsZygoteSpace()) { 317 return false; 318 } 319 } 320 return true; 321} 322 323bool Heap::HasImageSpace() const { 324 for (const auto& space : continuous_spaces_) { 325 if (space->IsImageSpace()) { 326 return true; 327 } 328 } 329 return false; 330} 331 332void Heap::IncrementDisableMovingGC(Thread* self) { 333 // Need to do this holding the lock to prevent races where the GC is about to run / running when 334 // we attempt to disable it. 335 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 336 MutexLock mu(self, *gc_complete_lock_); 337 ++disable_moving_gc_count_; 338 if (IsCompactingGC(collector_type_running_)) { 339 WaitForGcToCompleteLocked(self); 340 } 341} 342 343void Heap::DecrementDisableMovingGC(Thread* self) { 344 MutexLock mu(self, *gc_complete_lock_); 345 CHECK_GE(disable_moving_gc_count_, 0U); 346 --disable_moving_gc_count_; 347} 348 349void Heap::UpdateProcessState(ProcessState process_state) { 350 if (process_state_ != process_state) { 351 process_state_ = process_state; 352 if (process_state_ == kProcessStateJankPerceptible) { 353 TransitionCollector(post_zygote_collector_type_); 354 } else { 355 TransitionCollector(background_collector_type_); 356 } 357 } else { 358 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 359 } 360} 361 362void Heap::CreateThreadPool() { 363 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 364 if (num_threads != 0) { 365 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 366 } 367} 368 369void Heap::VisitObjects(ObjectVisitorCallback callback, void* arg) { 370 Thread* self = Thread::Current(); 371 // GCs can move objects, so don't allow this. 372 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 373 if (bump_pointer_space_ != nullptr) { 374 // Visit objects in bump pointer space. 375 bump_pointer_space_->Walk(callback, arg); 376 } 377 // TODO: Switch to standard begin and end to use ranged a based loop. 378 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 379 it < end; ++it) { 380 mirror::Object* obj = *it; 381 callback(obj, arg); 382 } 383 GetLiveBitmap()->Walk(callback, arg); 384 self->EndAssertNoThreadSuspension(old_cause); 385} 386 387void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 388 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 389 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 390 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 391 // TODO: Generalize this to n bitmaps? 392 if (space1 == nullptr) { 393 DCHECK(space2 != nullptr); 394 space1 = space2; 395 } 396 if (space2 == nullptr) { 397 DCHECK(space1 != nullptr); 398 space2 = space1; 399 } 400 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 401 large_object_space_->GetLiveObjects(), stack); 402} 403 404void Heap::DeleteThreadPool() { 405 thread_pool_.reset(nullptr); 406} 407 408void Heap::AddSpace(space::Space* space, bool set_as_default) { 409 DCHECK(space != nullptr); 410 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 411 if (space->IsContinuousSpace()) { 412 DCHECK(!space->IsDiscontinuousSpace()); 413 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 414 // Continuous spaces don't necessarily have bitmaps. 415 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 416 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 417 if (live_bitmap != nullptr) { 418 DCHECK(mark_bitmap != nullptr); 419 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 420 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 421 } 422 continuous_spaces_.push_back(continuous_space); 423 if (set_as_default) { 424 if (continuous_space->IsDlMallocSpace()) { 425 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 426 } else if (continuous_space->IsRosAllocSpace()) { 427 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 428 } 429 } 430 // Ensure that spaces remain sorted in increasing order of start address. 431 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 432 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 433 return a->Begin() < b->Begin(); 434 }); 435 } else { 436 DCHECK(space->IsDiscontinuousSpace()); 437 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 438 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 439 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 440 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 441 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 442 discontinuous_spaces_.push_back(discontinuous_space); 443 } 444 if (space->IsAllocSpace()) { 445 alloc_spaces_.push_back(space->AsAllocSpace()); 446 } 447} 448 449void Heap::RemoveSpace(space::Space* space) { 450 DCHECK(space != nullptr); 451 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 452 if (space->IsContinuousSpace()) { 453 DCHECK(!space->IsDiscontinuousSpace()); 454 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 455 // Continuous spaces don't necessarily have bitmaps. 456 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 457 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 458 if (live_bitmap != nullptr) { 459 DCHECK(mark_bitmap != nullptr); 460 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 461 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 462 } 463 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 464 DCHECK(it != continuous_spaces_.end()); 465 continuous_spaces_.erase(it); 466 if (continuous_space == dlmalloc_space_) { 467 dlmalloc_space_ = nullptr; 468 } else if (continuous_space == rosalloc_space_) { 469 rosalloc_space_ = nullptr; 470 } 471 if (continuous_space == main_space_) { 472 main_space_ = nullptr; 473 } 474 } else { 475 DCHECK(space->IsDiscontinuousSpace()); 476 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 477 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 478 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 479 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 480 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 481 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 482 discontinuous_space); 483 DCHECK(it != discontinuous_spaces_.end()); 484 discontinuous_spaces_.erase(it); 485 } 486 if (space->IsAllocSpace()) { 487 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 488 DCHECK(it != alloc_spaces_.end()); 489 alloc_spaces_.erase(it); 490 } 491} 492 493void Heap::RegisterGCAllocation(size_t bytes) { 494 if (this != nullptr) { 495 gc_memory_overhead_.FetchAndAdd(bytes); 496 } 497} 498 499void Heap::RegisterGCDeAllocation(size_t bytes) { 500 if (this != nullptr) { 501 gc_memory_overhead_.FetchAndSub(bytes); 502 } 503} 504 505void Heap::DumpGcPerformanceInfo(std::ostream& os) { 506 // Dump cumulative timings. 507 os << "Dumping cumulative Gc timings\n"; 508 uint64_t total_duration = 0; 509 510 // Dump cumulative loggers for each GC type. 511 uint64_t total_paused_time = 0; 512 for (const auto& collector : garbage_collectors_) { 513 CumulativeLogger& logger = collector->GetCumulativeTimings(); 514 if (logger.GetTotalNs() != 0) { 515 os << Dumpable<CumulativeLogger>(logger); 516 const uint64_t total_ns = logger.GetTotalNs(); 517 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 518 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 519 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 520 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 521 Histogram<uint64_t>::CumulativeData cumulative_data; 522 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 523 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 524 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 525 << collector->GetName() << " freed: " << freed_objects 526 << " objects with total size " << PrettySize(freed_bytes) << "\n" 527 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 528 << PrettySize(freed_bytes / seconds) << "/s\n"; 529 total_duration += total_ns; 530 total_paused_time += total_pause_ns; 531 } 532 } 533 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 534 if (total_duration != 0) { 535 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 536 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 537 os << "Mean GC size throughput: " 538 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 539 os << "Mean GC object throughput: " 540 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 541 } 542 size_t total_objects_allocated = GetObjectsAllocatedEver(); 543 os << "Total number of allocations: " << total_objects_allocated << "\n"; 544 size_t total_bytes_allocated = GetBytesAllocatedEver(); 545 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 546 if (kMeasureAllocationTime) { 547 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 548 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 549 << "\n"; 550 } 551 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 552 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 553 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 554} 555 556Heap::~Heap() { 557 VLOG(heap) << "Starting ~Heap()"; 558 STLDeleteElements(&garbage_collectors_); 559 // If we don't reset then the mark stack complains in its destructor. 560 allocation_stack_->Reset(); 561 live_stack_->Reset(); 562 STLDeleteValues(&mod_union_tables_); 563 STLDeleteElements(&continuous_spaces_); 564 STLDeleteElements(&discontinuous_spaces_); 565 delete gc_complete_lock_; 566 VLOG(heap) << "Finished ~Heap()"; 567} 568 569space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 570 bool fail_ok) const { 571 for (const auto& space : continuous_spaces_) { 572 if (space->Contains(obj)) { 573 return space; 574 } 575 } 576 if (!fail_ok) { 577 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 578 } 579 return NULL; 580} 581 582space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 583 bool fail_ok) const { 584 for (const auto& space : discontinuous_spaces_) { 585 if (space->Contains(obj)) { 586 return space; 587 } 588 } 589 if (!fail_ok) { 590 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 591 } 592 return NULL; 593} 594 595space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 596 space::Space* result = FindContinuousSpaceFromObject(obj, true); 597 if (result != NULL) { 598 return result; 599 } 600 return FindDiscontinuousSpaceFromObject(obj, true); 601} 602 603struct SoftReferenceArgs { 604 RootVisitor* is_marked_callback_; 605 RootVisitor* recursive_mark_callback_; 606 void* arg_; 607}; 608 609mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 610 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 611 // TODO: Not preserve all soft references. 612 return args->recursive_mark_callback_(obj, args->arg_); 613} 614 615// Process reference class instances and schedule finalizations. 616void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 617 RootVisitor* is_marked_callback, 618 RootVisitor* recursive_mark_object_callback, void* arg) { 619 // Unless we are in the zygote or required to clear soft references with white references, 620 // preserve some white referents. 621 if (!clear_soft && !Runtime::Current()->IsZygote()) { 622 SoftReferenceArgs soft_reference_args; 623 soft_reference_args.is_marked_callback_ = is_marked_callback; 624 soft_reference_args.recursive_mark_callback_ = recursive_mark_object_callback; 625 soft_reference_args.arg_ = arg; 626 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 627 &soft_reference_args); 628 } 629 timings.StartSplit("ProcessReferences"); 630 // Clear all remaining soft and weak references with white referents. 631 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 632 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 633 timings.EndSplit(); 634 // Preserve all white objects with finalize methods and schedule them for finalization. 635 timings.StartSplit("EnqueueFinalizerReferences"); 636 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 637 recursive_mark_object_callback, arg); 638 timings.EndSplit(); 639 timings.StartSplit("ProcessReferences"); 640 // Clear all f-reachable soft and weak references with white referents. 641 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 642 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 643 // Clear all phantom references with white referents. 644 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 645 // At this point all reference queues other than the cleared references should be empty. 646 DCHECK(soft_reference_queue_.IsEmpty()); 647 DCHECK(weak_reference_queue_.IsEmpty()); 648 DCHECK(finalizer_reference_queue_.IsEmpty()); 649 DCHECK(phantom_reference_queue_.IsEmpty()); 650 timings.EndSplit(); 651} 652 653bool Heap::IsEnqueued(mirror::Object* ref) const { 654 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 655 // will always be non-null. 656 return ref->GetFieldObject<mirror::Object>(GetReferencePendingNextOffset(), false) != nullptr; 657} 658 659bool Heap::IsEnqueuable(mirror::Object* ref) const { 660 DCHECK(ref != nullptr); 661 const mirror::Object* queue = 662 ref->GetFieldObject<mirror::Object>(GetReferenceQueueOffset(), false); 663 const mirror::Object* queue_next = 664 ref->GetFieldObject<mirror::Object>(GetReferenceQueueNextOffset(), false); 665 return queue != nullptr && queue_next == nullptr; 666} 667 668// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 669// marked, put it on the appropriate list in the heap for later processing. 670void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 671 RootVisitor mark_visitor, void* arg) { 672 DCHECK(klass != nullptr); 673 DCHECK(klass->IsReferenceClass()); 674 DCHECK(obj != nullptr); 675 mirror::Object* referent = GetReferenceReferent(obj); 676 if (referent != nullptr) { 677 mirror::Object* forward_address = mark_visitor(referent, arg); 678 // Null means that the object is not currently marked. 679 if (forward_address == nullptr) { 680 Thread* self = Thread::Current(); 681 // TODO: Remove these locks, and use atomic stacks for storing references? 682 // We need to check that the references haven't already been enqueued since we can end up 683 // scanning the same reference multiple times due to dirty cards. 684 if (klass->IsSoftReferenceClass()) { 685 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 686 } else if (klass->IsWeakReferenceClass()) { 687 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 688 } else if (klass->IsFinalizerReferenceClass()) { 689 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 690 } else if (klass->IsPhantomReferenceClass()) { 691 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 692 } else { 693 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 694 << klass->GetAccessFlags(); 695 } 696 } else if (referent != forward_address) { 697 // Referent is already marked and we need to update it. 698 SetReferenceReferent(obj, forward_address); 699 } 700 } 701} 702 703space::ImageSpace* Heap::GetImageSpace() const { 704 for (const auto& space : continuous_spaces_) { 705 if (space->IsImageSpace()) { 706 return space->AsImageSpace(); 707 } 708 } 709 return NULL; 710} 711 712static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 713 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 714 if (used_bytes < chunk_size) { 715 size_t chunk_free_bytes = chunk_size - used_bytes; 716 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 717 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 718 } 719} 720 721void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 722 std::ostringstream oss; 723 size_t total_bytes_free = GetFreeMemory(); 724 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 725 << " free bytes"; 726 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 727 if (!large_object_allocation && total_bytes_free >= byte_count) { 728 size_t max_contiguous_allocation = 0; 729 for (const auto& space : continuous_spaces_) { 730 if (space->IsMallocSpace()) { 731 // To allow the Walk/InspectAll() to exclusively-lock the mutator 732 // lock, temporarily release the shared access to the mutator 733 // lock here by transitioning to the suspended state. 734 Locks::mutator_lock_->AssertSharedHeld(self); 735 self->TransitionFromRunnableToSuspended(kSuspended); 736 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 737 self->TransitionFromSuspendedToRunnable(); 738 Locks::mutator_lock_->AssertSharedHeld(self); 739 } 740 } 741 oss << "; failed due to fragmentation (largest possible contiguous allocation " 742 << max_contiguous_allocation << " bytes)"; 743 } 744 self->ThrowOutOfMemoryError(oss.str().c_str()); 745} 746 747void Heap::Trim() { 748 Thread* self = Thread::Current(); 749 { 750 // Need to do this before acquiring the locks since we don't want to get suspended while 751 // holding any locks. 752 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 753 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 754 // trimming. 755 MutexLock mu(self, *gc_complete_lock_); 756 // Ensure there is only one GC at a time. 757 WaitForGcToCompleteLocked(self); 758 collector_type_running_ = kCollectorTypeHeapTrim; 759 } 760 uint64_t start_ns = NanoTime(); 761 // Trim the managed spaces. 762 uint64_t total_alloc_space_allocated = 0; 763 uint64_t total_alloc_space_size = 0; 764 uint64_t managed_reclaimed = 0; 765 for (const auto& space : continuous_spaces_) { 766 if (space->IsMallocSpace()) { 767 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 768 total_alloc_space_size += alloc_space->Size(); 769 managed_reclaimed += alloc_space->Trim(); 770 } 771 } 772 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 773 bump_pointer_space_->Size(); 774 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 775 static_cast<float>(total_alloc_space_size); 776 uint64_t gc_heap_end_ns = NanoTime(); 777 // We never move things in the native heap, so we can finish the GC at this point. 778 FinishGC(self, collector::kGcTypeNone); 779 // Trim the native heap. 780 dlmalloc_trim(0); 781 size_t native_reclaimed = 0; 782 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 783 uint64_t end_ns = NanoTime(); 784 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 785 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 786 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 787 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 788 << "%."; 789} 790 791bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 792 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 793 // taking the lock. 794 if (obj == nullptr) { 795 return true; 796 } 797 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 798} 799 800bool Heap::IsHeapAddress(const mirror::Object* obj) const { 801 if (kMovingCollector && bump_pointer_space_ && bump_pointer_space_->HasAddress(obj)) { 802 return true; 803 } 804 // TODO: This probably doesn't work for large objects. 805 return FindSpaceFromObject(obj, true) != nullptr; 806} 807 808bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 809 bool search_live_stack, bool sorted) { 810 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 811 return false; 812 } 813 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 814 mirror::Class* klass = obj->GetClass(); 815 if (obj == klass) { 816 // This case happens for java.lang.Class. 817 return true; 818 } 819 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 820 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 821 return false; 822 } 823 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 824 space::DiscontinuousSpace* d_space = NULL; 825 if (c_space != nullptr) { 826 if (c_space->GetLiveBitmap()->Test(obj)) { 827 return true; 828 } 829 } else { 830 d_space = FindDiscontinuousSpaceFromObject(obj, true); 831 if (d_space != nullptr) { 832 if (d_space->GetLiveObjects()->Test(obj)) { 833 return true; 834 } 835 } 836 } 837 // This is covering the allocation/live stack swapping that is done without mutators suspended. 838 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 839 if (i > 0) { 840 NanoSleep(MsToNs(10)); 841 } 842 if (search_allocation_stack) { 843 if (sorted) { 844 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 845 return true; 846 } 847 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 848 return true; 849 } 850 } 851 852 if (search_live_stack) { 853 if (sorted) { 854 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 855 return true; 856 } 857 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 858 return true; 859 } 860 } 861 } 862 // We need to check the bitmaps again since there is a race where we mark something as live and 863 // then clear the stack containing it. 864 if (c_space != nullptr) { 865 if (c_space->GetLiveBitmap()->Test(obj)) { 866 return true; 867 } 868 } else { 869 d_space = FindDiscontinuousSpaceFromObject(obj, true); 870 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 871 return true; 872 } 873 } 874 return false; 875} 876 877void Heap::VerifyObjectImpl(mirror::Object* obj) { 878 if (Thread::Current() == NULL || 879 Runtime::Current()->GetThreadList()->GetLockOwner() == Thread::Current()->GetTid()) { 880 return; 881 } 882 VerifyObjectBody(obj); 883} 884 885bool Heap::VerifyClassClass(const mirror::Class* c) const { 886 // Note: we don't use the accessors here as they have internal sanity checks that we don't want 887 // to run 888 const byte* raw_addr = 889 reinterpret_cast<const byte*>(c) + mirror::Object::ClassOffset().Int32Value(); 890 mirror::Class* c_c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 891 raw_addr = reinterpret_cast<const byte*>(c_c) + mirror::Object::ClassOffset().Int32Value(); 892 mirror::Class* c_c_c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 893 return c_c == c_c_c; 894} 895 896void Heap::DumpSpaces(std::ostream& stream) { 897 for (const auto& space : continuous_spaces_) { 898 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 899 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 900 stream << space << " " << *space << "\n"; 901 if (live_bitmap != nullptr) { 902 stream << live_bitmap << " " << *live_bitmap << "\n"; 903 } 904 if (mark_bitmap != nullptr) { 905 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 906 } 907 } 908 for (const auto& space : discontinuous_spaces_) { 909 stream << space << " " << *space << "\n"; 910 } 911} 912 913void Heap::VerifyObjectBody(mirror::Object* obj) { 914 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 915 // Ignore early dawn of the universe verifications. 916 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 917 return; 918 } 919 const byte* raw_addr = reinterpret_cast<const byte*>(obj) + 920 mirror::Object::ClassOffset().Int32Value(); 921 mirror::Class* c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 922 if (UNLIKELY(c == NULL)) { 923 LOG(FATAL) << "Null class in object: " << obj; 924 } else if (UNLIKELY(!IsAligned<kObjectAlignment>(c))) { 925 LOG(FATAL) << "Class isn't aligned: " << c << " in object: " << obj; 926 } 927 CHECK(VerifyClassClass(c)); 928 929 if (verify_object_mode_ > kVerifyAllFast) { 930 // TODO: the bitmap tests below are racy if VerifyObjectBody is called without the 931 // heap_bitmap_lock_. 932 if (!IsLiveObjectLocked(obj)) { 933 DumpSpaces(); 934 LOG(FATAL) << "Object is dead: " << obj; 935 } 936 if (!IsLiveObjectLocked(c)) { 937 LOG(FATAL) << "Class of object is dead: " << c << " in object: " << obj; 938 } 939 } 940} 941 942void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 943 DCHECK(obj != NULL); 944 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 945} 946 947void Heap::VerifyHeap() { 948 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 949 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 950} 951 952void Heap::RecordFree(size_t freed_objects, size_t freed_bytes) { 953 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 954 num_bytes_allocated_.FetchAndSub(freed_bytes); 955 if (Runtime::Current()->HasStatsEnabled()) { 956 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 957 thread_stats->freed_objects += freed_objects; 958 thread_stats->freed_bytes += freed_bytes; 959 // TODO: Do this concurrently. 960 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 961 global_stats->freed_objects += freed_objects; 962 global_stats->freed_bytes += freed_bytes; 963 } 964} 965 966mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 967 size_t alloc_size, size_t* bytes_allocated, 968 mirror::Class** klass) { 969 mirror::Object* ptr = nullptr; 970 bool was_default_allocator = allocator == GetCurrentAllocator(); 971 DCHECK(klass != nullptr); 972 SirtRef<mirror::Class> sirt_klass(self, *klass); 973 // The allocation failed. If the GC is running, block until it completes, and then retry the 974 // allocation. 975 collector::GcType last_gc = WaitForGcToComplete(self); 976 if (last_gc != collector::kGcTypeNone) { 977 // If we were the default allocator but the allocator changed while we were suspended, 978 // abort the allocation. 979 if (was_default_allocator && allocator != GetCurrentAllocator()) { 980 *klass = sirt_klass.get(); 981 return nullptr; 982 } 983 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 984 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 985 } 986 987 // Loop through our different Gc types and try to Gc until we get enough free memory. 988 for (collector::GcType gc_type : gc_plan_) { 989 if (ptr != nullptr) { 990 break; 991 } 992 // Attempt to run the collector, if we succeed, re-try the allocation. 993 bool gc_ran = 994 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 995 if (was_default_allocator && allocator != GetCurrentAllocator()) { 996 *klass = sirt_klass.get(); 997 return nullptr; 998 } 999 if (gc_ran) { 1000 // Did we free sufficient memory for the allocation to succeed? 1001 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 1002 } 1003 } 1004 // Allocations have failed after GCs; this is an exceptional state. 1005 if (ptr == nullptr) { 1006 // Try harder, growing the heap if necessary. 1007 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1008 } 1009 if (ptr == nullptr) { 1010 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1011 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1012 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1013 // OOME. 1014 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1015 << " allocation"; 1016 // TODO: Run finalization, but this may cause more allocations to occur. 1017 // We don't need a WaitForGcToComplete here either. 1018 DCHECK(!gc_plan_.empty()); 1019 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1020 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1021 *klass = sirt_klass.get(); 1022 return nullptr; 1023 } 1024 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1025 if (ptr == nullptr) { 1026 ThrowOutOfMemoryError(self, alloc_size, false); 1027 } 1028 } 1029 *klass = sirt_klass.get(); 1030 return ptr; 1031} 1032 1033void Heap::SetTargetHeapUtilization(float target) { 1034 DCHECK_GT(target, 0.0f); // asserted in Java code 1035 DCHECK_LT(target, 1.0f); 1036 target_utilization_ = target; 1037} 1038 1039size_t Heap::GetObjectsAllocated() const { 1040 size_t total = 0; 1041 for (space::AllocSpace* space : alloc_spaces_) { 1042 total += space->GetObjectsAllocated(); 1043 } 1044 return total; 1045} 1046 1047size_t Heap::GetObjectsAllocatedEver() const { 1048 return GetObjectsFreedEver() + GetObjectsAllocated(); 1049} 1050 1051size_t Heap::GetBytesAllocatedEver() const { 1052 return GetBytesFreedEver() + GetBytesAllocated(); 1053} 1054 1055class InstanceCounter { 1056 public: 1057 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1058 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1059 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1060 } 1061 1062 void operator()(mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1063 for (size_t i = 0; i < classes_.size(); ++i) { 1064 mirror::Class* instance_class = o->GetClass(); 1065 if (use_is_assignable_from_) { 1066 if (instance_class != NULL && classes_[i]->IsAssignableFrom(instance_class)) { 1067 ++counts_[i]; 1068 } 1069 } else { 1070 if (instance_class == classes_[i]) { 1071 ++counts_[i]; 1072 } 1073 } 1074 } 1075 } 1076 1077 private: 1078 const std::vector<mirror::Class*>& classes_; 1079 bool use_is_assignable_from_; 1080 uint64_t* const counts_; 1081 1082 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1083}; 1084 1085void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1086 uint64_t* counts) { 1087 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1088 // is empty, so the live bitmap is the only place we need to look. 1089 Thread* self = Thread::Current(); 1090 self->TransitionFromRunnableToSuspended(kNative); 1091 CollectGarbage(false); 1092 self->TransitionFromSuspendedToRunnable(); 1093 1094 InstanceCounter counter(classes, use_is_assignable_from, counts); 1095 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1096 GetLiveBitmap()->Visit(counter); 1097} 1098 1099class InstanceCollector { 1100 public: 1101 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1102 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1103 : class_(c), max_count_(max_count), instances_(instances) { 1104 } 1105 1106 void operator()(mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1107 mirror::Class* instance_class = o->GetClass(); 1108 if (instance_class == class_) { 1109 if (max_count_ == 0 || instances_.size() < max_count_) { 1110 instances_.push_back(o); 1111 } 1112 } 1113 } 1114 1115 private: 1116 mirror::Class* class_; 1117 uint32_t max_count_; 1118 std::vector<mirror::Object*>& instances_; 1119 1120 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1121}; 1122 1123void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1124 std::vector<mirror::Object*>& instances) { 1125 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1126 // is empty, so the live bitmap is the only place we need to look. 1127 Thread* self = Thread::Current(); 1128 self->TransitionFromRunnableToSuspended(kNative); 1129 CollectGarbage(false); 1130 self->TransitionFromSuspendedToRunnable(); 1131 1132 InstanceCollector collector(c, max_count, instances); 1133 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1134 GetLiveBitmap()->Visit(collector); 1135} 1136 1137class ReferringObjectsFinder { 1138 public: 1139 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1140 std::vector<mirror::Object*>& referring_objects) 1141 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1142 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1143 } 1144 1145 // For bitmap Visit. 1146 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1147 // annotalysis on visitors. 1148 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1149 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1150 } 1151 1152 // For MarkSweep::VisitObjectReferences. 1153 void operator()(mirror::Object* referrer, mirror::Object* object, 1154 const MemberOffset&, bool) const { 1155 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1156 referring_objects_.push_back(referrer); 1157 } 1158 } 1159 1160 private: 1161 mirror::Object* object_; 1162 uint32_t max_count_; 1163 std::vector<mirror::Object*>& referring_objects_; 1164 1165 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1166}; 1167 1168void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1169 std::vector<mirror::Object*>& referring_objects) { 1170 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1171 // is empty, so the live bitmap is the only place we need to look. 1172 Thread* self = Thread::Current(); 1173 self->TransitionFromRunnableToSuspended(kNative); 1174 CollectGarbage(false); 1175 self->TransitionFromSuspendedToRunnable(); 1176 1177 ReferringObjectsFinder finder(o, max_count, referring_objects); 1178 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1179 GetLiveBitmap()->Visit(finder); 1180} 1181 1182void Heap::CollectGarbage(bool clear_soft_references) { 1183 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1184 // last GC will not have necessarily been cleared. 1185 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1186} 1187 1188void Heap::TransitionCollector(CollectorType collector_type) { 1189 if (collector_type == collector_type_) { 1190 return; 1191 } 1192 uint64_t start_time = NanoTime(); 1193 uint32_t before_size = GetTotalMemory(); 1194 uint32_t before_allocated = num_bytes_allocated_.Load(); 1195 ThreadList* tl = Runtime::Current()->GetThreadList(); 1196 Thread* self = Thread::Current(); 1197 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1198 Locks::mutator_lock_->AssertNotHeld(self); 1199 const bool copying_transition = 1200 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1201 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1202 // compacting_gc_disable_count_, this should rarely occurs). 1203 for (;;) { 1204 { 1205 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1206 MutexLock mu(self, *gc_complete_lock_); 1207 // Ensure there is only one GC at a time. 1208 WaitForGcToCompleteLocked(self); 1209 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1210 if (!copying_transition || disable_moving_gc_count_ == 0) { 1211 // TODO: Not hard code in semi-space collector? 1212 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1213 break; 1214 } 1215 } 1216 usleep(1000); 1217 } 1218 tl->SuspendAll(); 1219 switch (collector_type) { 1220 case kCollectorTypeSS: 1221 // Fall-through. 1222 case kCollectorTypeGSS: { 1223 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1224 CHECK(main_space_ != nullptr); 1225 Compact(temp_space_, main_space_); 1226 DCHECK(allocator_mem_map_.get() == nullptr); 1227 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1228 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1229 // RemoveSpace does not delete the removed space. 1230 space::Space* old_space = main_space_; 1231 RemoveSpace(old_space); 1232 delete old_space; 1233 break; 1234 } 1235 case kCollectorTypeMS: 1236 // Fall through. 1237 case kCollectorTypeCMS: { 1238 if (IsCompactingGC(collector_type_)) { 1239 // TODO: Use mem-map from temp space? 1240 MemMap* mem_map = allocator_mem_map_.release(); 1241 CHECK(mem_map != nullptr); 1242 size_t initial_size = kDefaultInitialSize; 1243 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1244 CHECK(main_space_ == nullptr); 1245 if (kUseRosAlloc) { 1246 main_space_ = 1247 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1248 initial_size, mem_map->Size(), 1249 mem_map->Size(), low_memory_mode_); 1250 } else { 1251 main_space_ = 1252 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1253 initial_size, mem_map->Size(), 1254 mem_map->Size()); 1255 } 1256 main_space_->SetFootprintLimit(main_space_->Capacity()); 1257 AddSpace(main_space_); 1258 Compact(main_space_, bump_pointer_space_); 1259 } 1260 break; 1261 } 1262 default: { 1263 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1264 break; 1265 } 1266 } 1267 ChangeCollector(collector_type); 1268 tl->ResumeAll(); 1269 // Can't call into java code with all threads suspended. 1270 EnqueueClearedReferences(); 1271 uint64_t duration = NanoTime() - start_time; 1272 GrowForUtilization(collector::kGcTypeFull, duration); 1273 FinishGC(self, collector::kGcTypeFull); 1274 int32_t after_size = GetTotalMemory(); 1275 int32_t delta_size = before_size - after_size; 1276 int32_t after_allocated = num_bytes_allocated_.Load(); 1277 int32_t delta_allocated = before_allocated - after_allocated; 1278 const std::string saved_bytes_str = 1279 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1280 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1281 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1282 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1283 << PrettySize(delta_size) << " saved"; 1284} 1285 1286void Heap::ChangeCollector(CollectorType collector_type) { 1287 // TODO: Only do this with all mutators suspended to avoid races. 1288 if (collector_type != collector_type_) { 1289 collector_type_ = collector_type; 1290 gc_plan_.clear(); 1291 switch (collector_type_) { 1292 case kCollectorTypeSS: 1293 // Fall-through. 1294 case kCollectorTypeGSS: { 1295 concurrent_gc_ = false; 1296 gc_plan_.push_back(collector::kGcTypeFull); 1297 if (use_tlab_) { 1298 ChangeAllocator(kAllocatorTypeTLAB); 1299 } else { 1300 ChangeAllocator(kAllocatorTypeBumpPointer); 1301 } 1302 break; 1303 } 1304 case kCollectorTypeMS: { 1305 concurrent_gc_ = false; 1306 gc_plan_.push_back(collector::kGcTypeSticky); 1307 gc_plan_.push_back(collector::kGcTypePartial); 1308 gc_plan_.push_back(collector::kGcTypeFull); 1309 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1310 break; 1311 } 1312 case kCollectorTypeCMS: { 1313 concurrent_gc_ = true; 1314 gc_plan_.push_back(collector::kGcTypeSticky); 1315 gc_plan_.push_back(collector::kGcTypePartial); 1316 gc_plan_.push_back(collector::kGcTypeFull); 1317 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1318 break; 1319 } 1320 default: { 1321 LOG(FATAL) << "Unimplemented"; 1322 } 1323 } 1324 if (concurrent_gc_) { 1325 concurrent_start_bytes_ = 1326 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1327 } else { 1328 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1329 } 1330 } 1331} 1332 1333// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1334class ZygoteCompactingCollector : public collector::SemiSpace { 1335 public: 1336 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector") { 1337 } 1338 1339 void BuildBins(space::ContinuousSpace* space) { 1340 bin_live_bitmap_ = space->GetLiveBitmap(); 1341 bin_mark_bitmap_ = space->GetMarkBitmap(); 1342 BinContext context; 1343 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1344 context.collector_ = this; 1345 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1346 // Note: This requires traversing the space in increasing order of object addresses. 1347 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1348 // Add the last bin which spans after the last object to the end of the space. 1349 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1350 } 1351 1352 private: 1353 struct BinContext { 1354 uintptr_t prev_; // The end of the previous object. 1355 ZygoteCompactingCollector* collector_; 1356 }; 1357 // Maps from bin sizes to locations. 1358 std::multimap<size_t, uintptr_t> bins_; 1359 // Live bitmap of the space which contains the bins. 1360 accounting::SpaceBitmap* bin_live_bitmap_; 1361 // Mark bitmap of the space which contains the bins. 1362 accounting::SpaceBitmap* bin_mark_bitmap_; 1363 1364 static void Callback(mirror::Object* obj, void* arg) 1365 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1366 DCHECK(arg != nullptr); 1367 BinContext* context = reinterpret_cast<BinContext*>(arg); 1368 ZygoteCompactingCollector* collector = context->collector_; 1369 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1370 size_t bin_size = object_addr - context->prev_; 1371 // Add the bin consisting of the end of the previous object to the start of the current object. 1372 collector->AddBin(bin_size, context->prev_); 1373 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1374 } 1375 1376 void AddBin(size_t size, uintptr_t position) { 1377 if (size != 0) { 1378 bins_.insert(std::make_pair(size, position)); 1379 } 1380 } 1381 1382 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1383 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1384 // allocator. 1385 return false; 1386 } 1387 1388 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1389 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1390 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1391 mirror::Object* forward_address; 1392 // Find the smallest bin which we can move obj in. 1393 auto it = bins_.lower_bound(object_size); 1394 if (it == bins_.end()) { 1395 // No available space in the bins, place it in the target space instead (grows the zygote 1396 // space). 1397 size_t bytes_allocated; 1398 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated); 1399 if (to_space_live_bitmap_ != nullptr) { 1400 to_space_live_bitmap_->Set(forward_address); 1401 } else { 1402 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1403 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1404 } 1405 } else { 1406 size_t size = it->first; 1407 uintptr_t pos = it->second; 1408 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1409 forward_address = reinterpret_cast<mirror::Object*>(pos); 1410 // Set the live and mark bits so that sweeping system weaks works properly. 1411 bin_live_bitmap_->Set(forward_address); 1412 bin_mark_bitmap_->Set(forward_address); 1413 DCHECK_GE(size, object_size); 1414 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1415 } 1416 // Copy the object over to its new location. 1417 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1418 return forward_address; 1419 } 1420}; 1421 1422void Heap::UnBindBitmaps() { 1423 for (const auto& space : GetContinuousSpaces()) { 1424 if (space->IsContinuousMemMapAllocSpace()) { 1425 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1426 if (alloc_space->HasBoundBitmaps()) { 1427 alloc_space->UnBindBitmaps(); 1428 } 1429 } 1430 } 1431} 1432 1433void Heap::PreZygoteFork() { 1434 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1435 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1436 Thread* self = Thread::Current(); 1437 MutexLock mu(self, zygote_creation_lock_); 1438 // Try to see if we have any Zygote spaces. 1439 if (have_zygote_space_) { 1440 return; 1441 } 1442 VLOG(heap) << "Starting PreZygoteFork"; 1443 // Trim the pages at the end of the non moving space. 1444 non_moving_space_->Trim(); 1445 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1446 // Change the collector to the post zygote one. 1447 ChangeCollector(post_zygote_collector_type_); 1448 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1449 if (semi_space_collector_ != nullptr) { 1450 ZygoteCompactingCollector zygote_collector(this); 1451 zygote_collector.BuildBins(non_moving_space_); 1452 // Create a new bump pointer space which we will compact into. 1453 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1454 non_moving_space_->Limit()); 1455 // Compact the bump pointer space to a new zygote bump pointer space. 1456 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1457 zygote_collector.SetFromSpace(bump_pointer_space_); 1458 zygote_collector.SetToSpace(&target_space); 1459 zygote_collector.Run(kGcCauseCollectorTransition, false); 1460 CHECK(temp_space_->IsEmpty()); 1461 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1462 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1463 // Update the end and write out image. 1464 non_moving_space_->SetEnd(target_space.End()); 1465 non_moving_space_->SetLimit(target_space.Limit()); 1466 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1467 } 1468 // Save the old space so that we can remove it after we complete creating the zygote space. 1469 space::MallocSpace* old_alloc_space = non_moving_space_; 1470 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1471 // the remaining available space. 1472 // Remove the old space before creating the zygote space since creating the zygote space sets 1473 // the old alloc space's bitmaps to nullptr. 1474 RemoveSpace(old_alloc_space); 1475 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1476 low_memory_mode_, 1477 &main_space_); 1478 delete old_alloc_space; 1479 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1480 AddSpace(zygote_space, false); 1481 CHECK(main_space_ != nullptr); 1482 if (main_space_->IsRosAllocSpace()) { 1483 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1484 } else if (main_space_->IsDlMallocSpace()) { 1485 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1486 } 1487 main_space_->SetFootprintLimit(main_space_->Capacity()); 1488 AddSpace(main_space_); 1489 have_zygote_space_ = true; 1490 // Create the zygote space mod union table. 1491 accounting::ModUnionTable* mod_union_table = 1492 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1493 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1494 AddModUnionTable(mod_union_table); 1495 // Reset the cumulative loggers since we now have a few additional timing phases. 1496 for (const auto& collector : garbage_collectors_) { 1497 collector->ResetCumulativeStatistics(); 1498 } 1499 // Can't use RosAlloc for non moving space due to thread local buffers. 1500 // TODO: Non limited space for non-movable objects? 1501 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1502 space::MallocSpace* new_non_moving_space = 1503 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1504 2 * MB, mem_map->Size(), mem_map->Size()); 1505 AddSpace(new_non_moving_space, false); 1506 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1507 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1508 non_moving_space_ = new_non_moving_space; 1509} 1510 1511void Heap::FlushAllocStack() { 1512 MarkAllocStackAsLive(allocation_stack_.get()); 1513 allocation_stack_->Reset(); 1514} 1515 1516void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1517 accounting::SpaceBitmap* bitmap2, 1518 accounting::ObjectSet* large_objects, 1519 accounting::ObjectStack* stack) { 1520 DCHECK(bitmap1 != nullptr); 1521 DCHECK(bitmap2 != nullptr); 1522 mirror::Object** limit = stack->End(); 1523 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1524 const mirror::Object* obj = *it; 1525 DCHECK(obj != nullptr); 1526 if (bitmap1->HasAddress(obj)) { 1527 bitmap1->Set(obj); 1528 } else if (bitmap2->HasAddress(obj)) { 1529 bitmap2->Set(obj); 1530 } else { 1531 large_objects->Set(obj); 1532 } 1533 } 1534} 1535 1536void Heap::SwapSemiSpaces() { 1537 // Swap the spaces so we allocate into the space which we just evacuated. 1538 std::swap(bump_pointer_space_, temp_space_); 1539} 1540 1541void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1542 space::ContinuousMemMapAllocSpace* source_space) { 1543 CHECK(kMovingCollector); 1544 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1545 if (target_space != source_space) { 1546 semi_space_collector_->SetFromSpace(source_space); 1547 semi_space_collector_->SetToSpace(target_space); 1548 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1549 } 1550} 1551 1552collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1553 bool clear_soft_references) { 1554 Thread* self = Thread::Current(); 1555 Runtime* runtime = Runtime::Current(); 1556 // If the heap can't run the GC, silently fail and return that no GC was run. 1557 switch (gc_type) { 1558 case collector::kGcTypePartial: { 1559 if (!have_zygote_space_) { 1560 return collector::kGcTypeNone; 1561 } 1562 break; 1563 } 1564 default: { 1565 // Other GC types don't have any special cases which makes them not runnable. The main case 1566 // here is full GC. 1567 } 1568 } 1569 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1570 Locks::mutator_lock_->AssertNotHeld(self); 1571 if (self->IsHandlingStackOverflow()) { 1572 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1573 } 1574 bool compacting_gc; 1575 { 1576 gc_complete_lock_->AssertNotHeld(self); 1577 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1578 MutexLock mu(self, *gc_complete_lock_); 1579 // Ensure there is only one GC at a time. 1580 WaitForGcToCompleteLocked(self); 1581 compacting_gc = IsCompactingGC(collector_type_); 1582 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1583 if (compacting_gc && disable_moving_gc_count_ != 0) { 1584 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1585 return collector::kGcTypeNone; 1586 } 1587 collector_type_running_ = collector_type_; 1588 } 1589 1590 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1591 ++runtime->GetStats()->gc_for_alloc_count; 1592 ++self->GetStats()->gc_for_alloc_count; 1593 } 1594 uint64_t gc_start_time_ns = NanoTime(); 1595 uint64_t gc_start_size = GetBytesAllocated(); 1596 // Approximate allocation rate in bytes / second. 1597 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1598 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1599 if (LIKELY(ms_delta != 0)) { 1600 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1601 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1602 } 1603 1604 DCHECK_LT(gc_type, collector::kGcTypeMax); 1605 DCHECK_NE(gc_type, collector::kGcTypeNone); 1606 1607 collector::GarbageCollector* collector = nullptr; 1608 // TODO: Clean this up. 1609 if (compacting_gc) { 1610 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1611 current_allocator_ == kAllocatorTypeTLAB); 1612 gc_type = semi_space_collector_->GetGcType(); 1613 CHECK(temp_space_->IsEmpty()); 1614 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1615 semi_space_collector_->SetToSpace(temp_space_); 1616 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1617 collector = semi_space_collector_; 1618 gc_type = collector::kGcTypeFull; 1619 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1620 current_allocator_ == kAllocatorTypeDlMalloc) { 1621 for (const auto& cur_collector : garbage_collectors_) { 1622 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1623 cur_collector->GetGcType() == gc_type) { 1624 collector = cur_collector; 1625 break; 1626 } 1627 } 1628 } else { 1629 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1630 } 1631 CHECK(collector != nullptr) 1632 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1633 << " and type=" << gc_type; 1634 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1635 collector->Run(gc_cause, clear_soft_references); 1636 total_objects_freed_ever_ += collector->GetFreedObjects(); 1637 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1638 // Enqueue cleared references. 1639 EnqueueClearedReferences(); 1640 // Grow the heap so that we know when to perform the next GC. 1641 GrowForUtilization(gc_type, collector->GetDurationNs()); 1642 if (CareAboutPauseTimes()) { 1643 const size_t duration = collector->GetDurationNs(); 1644 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1645 // GC for alloc pauses the allocating thread, so consider it as a pause. 1646 bool was_slow = duration > long_gc_log_threshold_ || 1647 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1648 if (!was_slow) { 1649 for (uint64_t pause : pauses) { 1650 was_slow = was_slow || pause > long_pause_log_threshold_; 1651 } 1652 } 1653 if (was_slow) { 1654 const size_t percent_free = GetPercentFree(); 1655 const size_t current_heap_size = GetBytesAllocated(); 1656 const size_t total_memory = GetTotalMemory(); 1657 std::ostringstream pause_string; 1658 for (size_t i = 0; i < pauses.size(); ++i) { 1659 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1660 << ((i != pauses.size() - 1) ? ", " : ""); 1661 } 1662 LOG(INFO) << gc_cause << " " << collector->GetName() 1663 << " GC freed " << collector->GetFreedObjects() << "(" 1664 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1665 << collector->GetFreedLargeObjects() << "(" 1666 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1667 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1668 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1669 << " total " << PrettyDuration((duration / 1000) * 1000); 1670 if (VLOG_IS_ON(heap)) { 1671 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1672 } 1673 } 1674 } 1675 FinishGC(self, gc_type); 1676 ATRACE_END(); 1677 1678 // Inform DDMS that a GC completed. 1679 Dbg::GcDidFinish(); 1680 return gc_type; 1681} 1682 1683void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1684 MutexLock mu(self, *gc_complete_lock_); 1685 collector_type_running_ = kCollectorTypeNone; 1686 if (gc_type != collector::kGcTypeNone) { 1687 last_gc_type_ = gc_type; 1688 } 1689 // Wake anyone who may have been waiting for the GC to complete. 1690 gc_complete_cond_->Broadcast(self); 1691} 1692 1693static mirror::Object* RootMatchesObjectVisitor(mirror::Object* root, void* arg) { 1694 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1695 if (root == obj) { 1696 LOG(INFO) << "Object " << obj << " is a root"; 1697 } 1698 return root; 1699} 1700 1701class ScanVisitor { 1702 public: 1703 void operator()(const mirror::Object* obj) const { 1704 LOG(ERROR) << "Would have rescanned object " << obj; 1705 } 1706}; 1707 1708// Verify a reference from an object. 1709class VerifyReferenceVisitor { 1710 public: 1711 explicit VerifyReferenceVisitor(Heap* heap) 1712 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1713 : heap_(heap), failed_(false) {} 1714 1715 bool Failed() const { 1716 return failed_; 1717 } 1718 1719 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1720 // analysis on visitors. 1721 void operator()(mirror::Object* obj, mirror::Object* ref, 1722 const MemberOffset& offset, bool /* is_static */) const 1723 NO_THREAD_SAFETY_ANALYSIS { 1724 if (ref == nullptr || IsLive(ref)) { 1725 // Verify that the reference is live. 1726 return; 1727 } 1728 if (!failed_) { 1729 // Print message on only on first failure to prevent spam. 1730 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1731 failed_ = true; 1732 } 1733 if (obj != nullptr) { 1734 accounting::CardTable* card_table = heap_->GetCardTable(); 1735 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1736 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1737 byte* card_addr = card_table->CardFromAddr(obj); 1738 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1739 << offset << "\n card value = " << static_cast<int>(*card_addr); 1740 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1741 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1742 } else { 1743 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1744 } 1745 1746 // Attmept to find the class inside of the recently freed objects. 1747 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1748 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1749 space::MallocSpace* space = ref_space->AsMallocSpace(); 1750 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1751 if (ref_class != nullptr) { 1752 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1753 << PrettyClass(ref_class); 1754 } else { 1755 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1756 } 1757 } 1758 1759 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1760 ref->GetClass()->IsClass()) { 1761 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1762 } else { 1763 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1764 << ") is not a valid heap address"; 1765 } 1766 1767 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1768 void* cover_begin = card_table->AddrFromCard(card_addr); 1769 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1770 accounting::CardTable::kCardSize); 1771 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1772 << "-" << cover_end; 1773 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1774 1775 if (bitmap == nullptr) { 1776 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1777 if (!heap_->VerifyClassClass(obj->GetClass())) { 1778 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1779 } 1780 } else { 1781 // Print out how the object is live. 1782 if (bitmap->Test(obj)) { 1783 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1784 } 1785 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1786 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1787 } 1788 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1789 LOG(ERROR) << "Object " << obj << " found in live stack"; 1790 } 1791 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1792 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1793 } 1794 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1795 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1796 } 1797 // Attempt to see if the card table missed the reference. 1798 ScanVisitor scan_visitor; 1799 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1800 card_table->Scan(bitmap, byte_cover_begin, 1801 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1802 } 1803 1804 // Search to see if any of the roots reference our object. 1805 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1806 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1807 1808 // Search to see if any of the roots reference our reference. 1809 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1810 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1811 } else { 1812 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 1813 } 1814 } 1815 1816 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1817 return heap_->IsLiveObjectLocked(obj, true, false, true); 1818 } 1819 1820 static mirror::Object* VerifyRoots(mirror::Object* root, void* arg) { 1821 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1822 (*visitor)(nullptr, root, MemberOffset(0), true); 1823 return root; 1824 } 1825 1826 private: 1827 Heap* const heap_; 1828 mutable bool failed_; 1829}; 1830 1831// Verify all references within an object, for use with HeapBitmap::Visit. 1832class VerifyObjectVisitor { 1833 public: 1834 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1835 1836 void operator()(mirror::Object* obj) const 1837 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1838 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1839 // be live or else how did we find it in the live bitmap? 1840 VerifyReferenceVisitor visitor(heap_); 1841 // The class doesn't count as a reference but we should verify it anyways. 1842 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1843 if (obj->GetClass()->IsReferenceClass()) { 1844 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1845 } 1846 failed_ = failed_ || visitor.Failed(); 1847 } 1848 1849 static void VisitCallback(mirror::Object* obj, void* arg) 1850 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1851 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1852 visitor->operator()(obj); 1853 } 1854 1855 bool Failed() const { 1856 return failed_; 1857 } 1858 1859 private: 1860 Heap* const heap_; 1861 mutable bool failed_; 1862}; 1863 1864// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1865bool Heap::VerifyHeapReferences() { 1866 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1867 // Lets sort our allocation stacks so that we can efficiently binary search them. 1868 allocation_stack_->Sort(); 1869 live_stack_->Sort(); 1870 VerifyObjectVisitor visitor(this); 1871 // Verify objects in the allocation stack since these will be objects which were: 1872 // 1. Allocated prior to the GC (pre GC verification). 1873 // 2. Allocated during the GC (pre sweep GC verification). 1874 // We don't want to verify the objects in the live stack since they themselves may be 1875 // pointing to dead objects if they are not reachable. 1876 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1877 // Verify the roots: 1878 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1879 if (visitor.Failed()) { 1880 // Dump mod-union tables. 1881 for (const auto& table_pair : mod_union_tables_) { 1882 accounting::ModUnionTable* mod_union_table = table_pair.second; 1883 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1884 } 1885 DumpSpaces(); 1886 return false; 1887 } 1888 return true; 1889} 1890 1891class VerifyReferenceCardVisitor { 1892 public: 1893 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1894 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1895 Locks::heap_bitmap_lock_) 1896 : heap_(heap), failed_(failed) { 1897 } 1898 1899 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1900 // annotalysis on visitors. 1901 void operator()(mirror::Object* obj, mirror::Object* ref, const MemberOffset& offset, 1902 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1903 // Filter out class references since changing an object's class does not mark the card as dirty. 1904 // Also handles large objects, since the only reference they hold is a class reference. 1905 if (ref != NULL && !ref->IsClass()) { 1906 accounting::CardTable* card_table = heap_->GetCardTable(); 1907 // If the object is not dirty and it is referencing something in the live stack other than 1908 // class, then it must be on a dirty card. 1909 if (!card_table->AddrIsInCardTable(obj)) { 1910 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1911 *failed_ = true; 1912 } else if (!card_table->IsDirty(obj)) { 1913 // TODO: Check mod-union tables. 1914 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1915 // kCardDirty - 1 if it didnt get touched since we aged it. 1916 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1917 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1918 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1919 LOG(ERROR) << "Object " << obj << " found in live stack"; 1920 } 1921 if (heap_->GetLiveBitmap()->Test(obj)) { 1922 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1923 } 1924 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1925 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1926 1927 // Print which field of the object is dead. 1928 if (!obj->IsObjectArray()) { 1929 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1930 CHECK(klass != NULL); 1931 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1932 : klass->GetIFields(); 1933 CHECK(fields != NULL); 1934 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1935 mirror::ArtField* cur = fields->Get(i); 1936 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1937 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1938 << PrettyField(cur); 1939 break; 1940 } 1941 } 1942 } else { 1943 mirror::ObjectArray<mirror::Object>* object_array = 1944 obj->AsObjectArray<mirror::Object>(); 1945 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1946 if (object_array->Get(i) == ref) { 1947 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1948 } 1949 } 1950 } 1951 1952 *failed_ = true; 1953 } 1954 } 1955 } 1956 } 1957 1958 private: 1959 Heap* const heap_; 1960 bool* const failed_; 1961}; 1962 1963class VerifyLiveStackReferences { 1964 public: 1965 explicit VerifyLiveStackReferences(Heap* heap) 1966 : heap_(heap), 1967 failed_(false) {} 1968 1969 void operator()(mirror::Object* obj) const 1970 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1971 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1972 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1973 } 1974 1975 bool Failed() const { 1976 return failed_; 1977 } 1978 1979 private: 1980 Heap* const heap_; 1981 bool failed_; 1982}; 1983 1984bool Heap::VerifyMissingCardMarks() { 1985 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1986 1987 // We need to sort the live stack since we binary search it. 1988 live_stack_->Sort(); 1989 VerifyLiveStackReferences visitor(this); 1990 GetLiveBitmap()->Visit(visitor); 1991 1992 // We can verify objects in the live stack since none of these should reference dead objects. 1993 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 1994 visitor(*it); 1995 } 1996 1997 if (visitor.Failed()) { 1998 DumpSpaces(); 1999 return false; 2000 } 2001 return true; 2002} 2003 2004void Heap::SwapStacks() { 2005 allocation_stack_.swap(live_stack_); 2006} 2007 2008accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2009 auto it = mod_union_tables_.find(space); 2010 if (it == mod_union_tables_.end()) { 2011 return nullptr; 2012 } 2013 return it->second; 2014} 2015 2016void Heap::ProcessCards(TimingLogger& timings) { 2017 // Clear cards and keep track of cards cleared in the mod-union table. 2018 for (const auto& space : continuous_spaces_) { 2019 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2020 if (table != nullptr) { 2021 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2022 "ImageModUnionClearCards"; 2023 TimingLogger::ScopedSplit split(name, &timings); 2024 table->ClearCards(); 2025 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2026 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2027 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2028 // were dirty before the GC started. 2029 // TODO: Don't need to use atomic. 2030 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2031 // roots and then we scan / update mod union tables after. We will always scan either card. 2032 // If we end up with the non aged card, we scan it it in the pause. 2033 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2034 } 2035 } 2036} 2037 2038static mirror::Object* IdentityCallback(mirror::Object* obj, void*) { 2039 return obj; 2040} 2041 2042void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2043 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2044 Thread* self = Thread::Current(); 2045 2046 if (verify_pre_gc_heap_) { 2047 thread_list->SuspendAll(); 2048 { 2049 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2050 if (!VerifyHeapReferences()) { 2051 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2052 } 2053 } 2054 thread_list->ResumeAll(); 2055 } 2056 2057 // Check that all objects which reference things in the live stack are on dirty cards. 2058 if (verify_missing_card_marks_) { 2059 thread_list->SuspendAll(); 2060 { 2061 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2062 SwapStacks(); 2063 // Sort the live stack so that we can quickly binary search it later. 2064 if (!VerifyMissingCardMarks()) { 2065 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2066 } 2067 SwapStacks(); 2068 } 2069 thread_list->ResumeAll(); 2070 } 2071 2072 if (verify_mod_union_table_) { 2073 thread_list->SuspendAll(); 2074 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2075 for (const auto& table_pair : mod_union_tables_) { 2076 accounting::ModUnionTable* mod_union_table = table_pair.second; 2077 mod_union_table->UpdateAndMarkReferences(IdentityCallback, nullptr); 2078 mod_union_table->Verify(); 2079 } 2080 thread_list->ResumeAll(); 2081 } 2082} 2083 2084void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2085 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2086 // reachable objects. 2087 if (verify_post_gc_heap_) { 2088 Thread* self = Thread::Current(); 2089 CHECK_NE(self->GetState(), kRunnable); 2090 { 2091 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2092 // Swapping bound bitmaps does nothing. 2093 gc->SwapBitmaps(); 2094 if (!VerifyHeapReferences()) { 2095 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2096 } 2097 gc->SwapBitmaps(); 2098 } 2099 } 2100} 2101 2102void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2103 if (verify_system_weaks_) { 2104 Thread* self = Thread::Current(); 2105 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2106 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2107 mark_sweep->VerifySystemWeaks(); 2108 } 2109} 2110 2111collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2112 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2113 MutexLock mu(self, *gc_complete_lock_); 2114 return WaitForGcToCompleteLocked(self); 2115} 2116 2117collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2118 collector::GcType last_gc_type = collector::kGcTypeNone; 2119 uint64_t wait_start = NanoTime(); 2120 while (collector_type_running_ != kCollectorTypeNone) { 2121 ATRACE_BEGIN("GC: Wait For Completion"); 2122 // We must wait, change thread state then sleep on gc_complete_cond_; 2123 gc_complete_cond_->Wait(self); 2124 last_gc_type = last_gc_type_; 2125 ATRACE_END(); 2126 } 2127 uint64_t wait_time = NanoTime() - wait_start; 2128 total_wait_time_ += wait_time; 2129 if (wait_time > long_pause_log_threshold_) { 2130 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2131 } 2132 return last_gc_type; 2133} 2134 2135void Heap::DumpForSigQuit(std::ostream& os) { 2136 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2137 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2138 DumpGcPerformanceInfo(os); 2139} 2140 2141size_t Heap::GetPercentFree() { 2142 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2143} 2144 2145void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2146 if (max_allowed_footprint > GetMaxMemory()) { 2147 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2148 << PrettySize(GetMaxMemory()); 2149 max_allowed_footprint = GetMaxMemory(); 2150 } 2151 max_allowed_footprint_ = max_allowed_footprint; 2152} 2153 2154bool Heap::IsMovableObject(const mirror::Object* obj) const { 2155 if (kMovingCollector) { 2156 DCHECK(!IsInTempSpace(obj)); 2157 if (bump_pointer_space_->HasAddress(obj)) { 2158 return true; 2159 } 2160 // TODO: Refactor this logic into the space itself? 2161 // Objects in the main space are only copied during background -> foreground transitions or 2162 // visa versa. 2163 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2164 (IsCompactingGC(background_collector_type_) || 2165 IsCompactingGC(post_zygote_collector_type_))) { 2166 return true; 2167 } 2168 } 2169 return false; 2170} 2171 2172bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2173 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2174 return true; 2175 } 2176 return false; 2177} 2178 2179void Heap::UpdateMaxNativeFootprint() { 2180 size_t native_size = native_bytes_allocated_; 2181 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2182 size_t target_size = native_size / GetTargetHeapUtilization(); 2183 if (target_size > native_size + max_free_) { 2184 target_size = native_size + max_free_; 2185 } else if (target_size < native_size + min_free_) { 2186 target_size = native_size + min_free_; 2187 } 2188 native_footprint_gc_watermark_ = target_size; 2189 native_footprint_limit_ = 2 * target_size - native_size; 2190} 2191 2192void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2193 // We know what our utilization is at this moment. 2194 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2195 const size_t bytes_allocated = GetBytesAllocated(); 2196 last_gc_size_ = bytes_allocated; 2197 last_gc_time_ns_ = NanoTime(); 2198 size_t target_size; 2199 if (gc_type != collector::kGcTypeSticky) { 2200 // Grow the heap for non sticky GC. 2201 target_size = bytes_allocated / GetTargetHeapUtilization(); 2202 if (target_size > bytes_allocated + max_free_) { 2203 target_size = bytes_allocated + max_free_; 2204 } else if (target_size < bytes_allocated + min_free_) { 2205 target_size = bytes_allocated + min_free_; 2206 } 2207 native_need_to_run_finalization_ = true; 2208 next_gc_type_ = collector::kGcTypeSticky; 2209 } else { 2210 // Based on how close the current heap size is to the target size, decide 2211 // whether or not to do a partial or sticky GC next. 2212 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2213 next_gc_type_ = collector::kGcTypeSticky; 2214 } else { 2215 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2216 } 2217 // If we have freed enough memory, shrink the heap back down. 2218 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2219 target_size = bytes_allocated + max_free_; 2220 } else { 2221 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2222 } 2223 } 2224 if (!ignore_max_footprint_) { 2225 SetIdealFootprint(target_size); 2226 if (concurrent_gc_) { 2227 // Calculate when to perform the next ConcurrentGC. 2228 // Calculate the estimated GC duration. 2229 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2230 // Estimate how many remaining bytes we will have when we need to start the next GC. 2231 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2232 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2233 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2234 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2235 // A never going to happen situation that from the estimated allocation rate we will exceed 2236 // the applications entire footprint with the given estimated allocation rate. Schedule 2237 // another GC nearly straight away. 2238 remaining_bytes = kMinConcurrentRemainingBytes; 2239 } 2240 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2241 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2242 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2243 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2244 // right away. 2245 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2246 } 2247 } 2248} 2249 2250void Heap::ClearGrowthLimit() { 2251 growth_limit_ = capacity_; 2252 non_moving_space_->ClearGrowthLimit(); 2253} 2254 2255void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2256 MemberOffset reference_queue_offset, 2257 MemberOffset reference_queueNext_offset, 2258 MemberOffset reference_pendingNext_offset, 2259 MemberOffset finalizer_reference_zombie_offset) { 2260 reference_referent_offset_ = reference_referent_offset; 2261 reference_queue_offset_ = reference_queue_offset; 2262 reference_queueNext_offset_ = reference_queueNext_offset; 2263 reference_pendingNext_offset_ = reference_pendingNext_offset; 2264 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2265 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2266 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2267 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2268 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2269 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2270} 2271 2272void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2273 DCHECK(reference != NULL); 2274 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2275 reference->SetFieldObject(reference_referent_offset_, referent, true); 2276} 2277 2278mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2279 DCHECK(reference != NULL); 2280 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2281 return reference->GetFieldObject<mirror::Object>(reference_referent_offset_, true); 2282} 2283 2284void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2285 ScopedObjectAccess soa(self); 2286 JValue result; 2287 ArgArray arg_array(NULL, 0); 2288 arg_array.Append(object); 2289 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2290 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2291} 2292 2293void Heap::EnqueueClearedReferences() { 2294 Thread* self = Thread::Current(); 2295 Locks::mutator_lock_->AssertNotHeld(self); 2296 if (!cleared_references_.IsEmpty()) { 2297 // When a runtime isn't started there are no reference queues to care about so ignore. 2298 if (LIKELY(Runtime::Current()->IsStarted())) { 2299 ScopedObjectAccess soa(self); 2300 JValue result; 2301 ArgArray arg_array(NULL, 0); 2302 arg_array.Append(cleared_references_.GetList()); 2303 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2304 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2305 } 2306 cleared_references_.Clear(); 2307 } 2308} 2309 2310void Heap::RequestConcurrentGC(Thread* self) { 2311 // Make sure that we can do a concurrent GC. 2312 Runtime* runtime = Runtime::Current(); 2313 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2314 self->IsHandlingStackOverflow()) { 2315 return; 2316 } 2317 // We already have a request pending, no reason to start more until we update 2318 // concurrent_start_bytes_. 2319 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2320 JNIEnv* env = self->GetJniEnv(); 2321 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2322 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2323 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2324 WellKnownClasses::java_lang_Daemons_requestGC); 2325 CHECK(!env->ExceptionCheck()); 2326} 2327 2328void Heap::ConcurrentGC(Thread* self) { 2329 if (Runtime::Current()->IsShuttingDown(self)) { 2330 return; 2331 } 2332 // Wait for any GCs currently running to finish. 2333 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2334 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2335 // instead. E.g. can't do partial, so do full instead. 2336 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2337 collector::kGcTypeNone) { 2338 for (collector::GcType gc_type : gc_plan_) { 2339 // Attempt to run the collector, if we succeed, we are done. 2340 if (gc_type > next_gc_type_ && 2341 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2342 break; 2343 } 2344 } 2345 } 2346 } 2347} 2348 2349void Heap::RequestHeapTrim() { 2350 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2351 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2352 // a space it will hold its lock and can become a cause of jank. 2353 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2354 // forking. 2355 2356 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2357 // because that only marks object heads, so a large array looks like lots of empty space. We 2358 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2359 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2360 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2361 // not how much use we're making of those pages. 2362 uint64_t ms_time = MilliTime(); 2363 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2364 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2365 return; 2366 } 2367 2368 Thread* self = Thread::Current(); 2369 Runtime* runtime = Runtime::Current(); 2370 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2371 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2372 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2373 // as we don't hold the lock while requesting the trim). 2374 return; 2375 } 2376 2377 last_trim_time_ms_ = ms_time; 2378 2379 // Trim only if we do not currently care about pause times. 2380 if (!CareAboutPauseTimes()) { 2381 JNIEnv* env = self->GetJniEnv(); 2382 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2383 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2384 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2385 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2386 CHECK(!env->ExceptionCheck()); 2387 } 2388} 2389 2390void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2391 if (rosalloc_space_ != nullptr) { 2392 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2393 } 2394 if (bump_pointer_space_ != nullptr) { 2395 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2396 } 2397} 2398 2399void Heap::RevokeAllThreadLocalBuffers() { 2400 if (rosalloc_space_ != nullptr) { 2401 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2402 } 2403 if (bump_pointer_space_ != nullptr) { 2404 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2405 } 2406} 2407 2408bool Heap::IsGCRequestPending() const { 2409 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2410} 2411 2412void Heap::RunFinalization(JNIEnv* env) { 2413 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2414 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2415 CHECK(WellKnownClasses::java_lang_System != nullptr); 2416 WellKnownClasses::java_lang_System_runFinalization = 2417 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2418 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2419 } 2420 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2421 WellKnownClasses::java_lang_System_runFinalization); 2422} 2423 2424void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2425 Thread* self = ThreadForEnv(env); 2426 if (native_need_to_run_finalization_) { 2427 RunFinalization(env); 2428 UpdateMaxNativeFootprint(); 2429 native_need_to_run_finalization_ = false; 2430 } 2431 // Total number of native bytes allocated. 2432 native_bytes_allocated_.FetchAndAdd(bytes); 2433 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2434 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2435 collector::kGcTypeFull; 2436 2437 // The second watermark is higher than the gc watermark. If you hit this it means you are 2438 // allocating native objects faster than the GC can keep up with. 2439 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2440 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2441 // Just finished a GC, attempt to run finalizers. 2442 RunFinalization(env); 2443 CHECK(!env->ExceptionCheck()); 2444 } 2445 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2446 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2447 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2448 RunFinalization(env); 2449 native_need_to_run_finalization_ = false; 2450 CHECK(!env->ExceptionCheck()); 2451 } 2452 // We have just run finalizers, update the native watermark since it is very likely that 2453 // finalizers released native managed allocations. 2454 UpdateMaxNativeFootprint(); 2455 } else if (!IsGCRequestPending()) { 2456 if (concurrent_gc_) { 2457 RequestConcurrentGC(self); 2458 } else { 2459 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2460 } 2461 } 2462 } 2463} 2464 2465void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2466 int expected_size, new_size; 2467 do { 2468 expected_size = native_bytes_allocated_.Load(); 2469 new_size = expected_size - bytes; 2470 if (UNLIKELY(new_size < 0)) { 2471 ScopedObjectAccess soa(env); 2472 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2473 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2474 "registered as allocated", bytes, expected_size).c_str()); 2475 break; 2476 } 2477 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2478} 2479 2480size_t Heap::GetTotalMemory() const { 2481 size_t ret = 0; 2482 for (const auto& space : continuous_spaces_) { 2483 // Currently don't include the image space. 2484 if (!space->IsImageSpace()) { 2485 ret += space->Size(); 2486 } 2487 } 2488 for (const auto& space : discontinuous_spaces_) { 2489 if (space->IsLargeObjectSpace()) { 2490 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2491 } 2492 } 2493 return ret; 2494} 2495 2496void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2497 DCHECK(mod_union_table != nullptr); 2498 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2499} 2500 2501} // namespace gc 2502} // namespace art 2503