heap.cc revision bd0a65339a08dc28c6b56d2673f1f13b6bddd7aa
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, bool verify_pre_gc_rosalloc, 85 bool verify_post_gc_rosalloc) 86 : non_moving_space_(nullptr), 87 rosalloc_space_(nullptr), 88 dlmalloc_space_(nullptr), 89 main_space_(nullptr), 90 concurrent_gc_(false), 91 collector_type_(kCollectorTypeNone), 92 post_zygote_collector_type_(post_zygote_collector_type), 93 background_collector_type_(background_collector_type), 94 parallel_gc_threads_(parallel_gc_threads), 95 conc_gc_threads_(conc_gc_threads), 96 low_memory_mode_(low_memory_mode), 97 long_pause_log_threshold_(long_pause_log_threshold), 98 long_gc_log_threshold_(long_gc_log_threshold), 99 ignore_max_footprint_(ignore_max_footprint), 100 have_zygote_space_(false), 101 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 102 soft_reference_queue_(this), 103 weak_reference_queue_(this), 104 finalizer_reference_queue_(this), 105 phantom_reference_queue_(this), 106 cleared_references_(this), 107 collector_type_running_(kCollectorTypeNone), 108 last_gc_type_(collector::kGcTypeNone), 109 next_gc_type_(collector::kGcTypePartial), 110 capacity_(capacity), 111 growth_limit_(growth_limit), 112 max_allowed_footprint_(initial_size), 113 native_footprint_gc_watermark_(initial_size), 114 native_footprint_limit_(2 * initial_size), 115 native_need_to_run_finalization_(false), 116 // Initially assume we perceive jank in case the process state is never updated. 117 process_state_(kProcessStateJankPerceptible), 118 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 119 total_bytes_freed_ever_(0), 120 total_objects_freed_ever_(0), 121 num_bytes_allocated_(0), 122 native_bytes_allocated_(0), 123 gc_memory_overhead_(0), 124 verify_missing_card_marks_(false), 125 verify_system_weaks_(false), 126 verify_pre_gc_heap_(verify_pre_gc_heap), 127 verify_post_gc_heap_(verify_post_gc_heap), 128 verify_mod_union_table_(false), 129 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 130 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 131 last_trim_time_ms_(0), 132 allocation_rate_(0), 133 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 134 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 135 * verification is enabled, we limit the size of allocation stacks to speed up their 136 * searching. 137 */ 138 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 139 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 140 current_allocator_(kAllocatorTypeDlMalloc), 141 current_non_moving_allocator_(kAllocatorTypeNonMoving), 142 bump_pointer_space_(nullptr), 143 temp_space_(nullptr), 144 reference_referent_offset_(0), 145 reference_queue_offset_(0), 146 reference_queueNext_offset_(0), 147 reference_pendingNext_offset_(0), 148 finalizer_reference_zombie_offset_(0), 149 min_free_(min_free), 150 max_free_(max_free), 151 target_utilization_(target_utilization), 152 total_wait_time_(0), 153 total_allocation_time_(0), 154 verify_object_mode_(kVerifyObjectModeDisabled), 155 disable_moving_gc_count_(0), 156 running_on_valgrind_(RUNNING_ON_VALGRIND), 157 use_tlab_(use_tlab) { 158 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 159 LOG(INFO) << "Heap() entering"; 160 } 161 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 162 // entrypoints. 163 if (!Runtime::Current()->IsZygote()) { 164 ChangeCollector(post_zygote_collector_type_); 165 large_object_threshold_ = kDefaultLargeObjectThreshold; 166 } else { 167 if (kMovingCollector) { 168 // We are the zygote, use bump pointer allocation + semi space collector. 169 ChangeCollector(kCollectorTypeSS); 170 } else { 171 ChangeCollector(post_zygote_collector_type_); 172 } 173 } 174 175 live_bitmap_.reset(new accounting::HeapBitmap(this)); 176 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 177 // Requested begin for the alloc space, to follow the mapped image and oat files 178 byte* requested_alloc_space_begin = nullptr; 179 if (!image_file_name.empty()) { 180 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 181 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 182 AddSpace(image_space); 183 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 184 // isn't going to get in the middle 185 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 186 CHECK_GT(oat_file_end_addr, image_space->End()); 187 if (oat_file_end_addr > requested_alloc_space_begin) { 188 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 189 } 190 } 191 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 192 space::MallocSpace* malloc_space; 193 if (kUseRosAlloc) { 194 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 195 requested_alloc_space_begin, low_memory_mode_); 196 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 197 } else { 198 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 199 requested_alloc_space_begin); 200 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 201 } 202 VLOG(heap) << "malloc_space : " << malloc_space; 203 if (kMovingCollector) { 204 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 205 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 206 // issues. 207 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 208 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 209 bump_pointer_space_size, nullptr); 210 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 211 AddSpace(bump_pointer_space_); 212 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 213 nullptr); 214 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 215 AddSpace(temp_space_); 216 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 217 VLOG(heap) << "temp_space : " << temp_space_; 218 } 219 non_moving_space_ = malloc_space; 220 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 221 AddSpace(malloc_space); 222 223 // Allocate the large object space. 224 constexpr bool kUseFreeListSpaceForLOS = false; 225 if (kUseFreeListSpaceForLOS) { 226 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 227 } else { 228 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 229 } 230 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 231 AddSpace(large_object_space_); 232 233 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 234 CHECK(!continuous_spaces_.empty()); 235 236 // Relies on the spaces being sorted. 237 byte* heap_begin = continuous_spaces_.front()->Begin(); 238 byte* heap_end = continuous_spaces_.back()->Limit(); 239 if (Runtime::Current()->IsZygote()) { 240 std::string error_str; 241 post_zygote_non_moving_space_mem_map_.reset( 242 MemMap::MapAnonymous("post zygote non-moving space", nullptr, 64 * MB, 243 PROT_READ | PROT_WRITE, true, &error_str)); 244 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 245 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 246 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 247 } 248 size_t heap_capacity = heap_end - heap_begin; 249 250 // Allocate the card table. 251 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 252 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 253 254 // Card cache for now since it makes it easier for us to update the references to the copying 255 // spaces. 256 accounting::ModUnionTable* mod_union_table = 257 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 258 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 259 AddModUnionTable(mod_union_table); 260 261 // TODO: Count objects in the image space here. 262 num_bytes_allocated_ = 0; 263 264 // Default mark stack size in bytes. 265 static const size_t default_mark_stack_size = 64 * KB; 266 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 267 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 268 max_allocation_stack_size_)); 269 live_stack_.reset(accounting::ObjectStack::Create("live stack", 270 max_allocation_stack_size_)); 271 272 // It's still too early to take a lock because there are no threads yet, but we can create locks 273 // now. We don't create it earlier to make it clear that you can't use locks during heap 274 // initialization. 275 gc_complete_lock_ = new Mutex("GC complete lock"); 276 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 277 *gc_complete_lock_)); 278 last_gc_time_ns_ = NanoTime(); 279 last_gc_size_ = GetBytesAllocated(); 280 281 if (ignore_max_footprint_) { 282 SetIdealFootprint(std::numeric_limits<size_t>::max()); 283 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 284 } 285 CHECK_NE(max_allowed_footprint_, 0U); 286 287 // Create our garbage collectors. 288 for (size_t i = 0; i < 2; ++i) { 289 const bool concurrent = i != 0; 290 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 291 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 292 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 293 } 294 if (kMovingCollector) { 295 // TODO: Clean this up. 296 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 297 semi_space_collector_ = new collector::SemiSpace(this, generational); 298 garbage_collectors_.push_back(semi_space_collector_); 299 } 300 301 if (running_on_valgrind_) { 302 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 303 } 304 305 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 306 LOG(INFO) << "Heap() exiting"; 307 } 308} 309 310void Heap::ChangeAllocator(AllocatorType allocator) { 311 // These two allocators are only used internally and don't have any entrypoints. 312 DCHECK_NE(allocator, kAllocatorTypeLOS); 313 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 314 if (current_allocator_ != allocator) { 315 current_allocator_ = allocator; 316 SetQuickAllocEntryPointsAllocator(current_allocator_); 317 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 318 } 319} 320 321bool Heap::IsCompilingBoot() const { 322 for (const auto& space : continuous_spaces_) { 323 if (space->IsImageSpace() || space->IsZygoteSpace()) { 324 return false; 325 } 326 } 327 return true; 328} 329 330bool Heap::HasImageSpace() const { 331 for (const auto& space : continuous_spaces_) { 332 if (space->IsImageSpace()) { 333 return true; 334 } 335 } 336 return false; 337} 338 339void Heap::IncrementDisableMovingGC(Thread* self) { 340 // Need to do this holding the lock to prevent races where the GC is about to run / running when 341 // we attempt to disable it. 342 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 343 MutexLock mu(self, *gc_complete_lock_); 344 ++disable_moving_gc_count_; 345 if (IsCompactingGC(collector_type_running_)) { 346 WaitForGcToCompleteLocked(self); 347 } 348} 349 350void Heap::DecrementDisableMovingGC(Thread* self) { 351 MutexLock mu(self, *gc_complete_lock_); 352 CHECK_GE(disable_moving_gc_count_, 0U); 353 --disable_moving_gc_count_; 354} 355 356void Heap::UpdateProcessState(ProcessState process_state) { 357 if (process_state_ != process_state) { 358 process_state_ = process_state; 359 if (process_state_ == kProcessStateJankPerceptible) { 360 TransitionCollector(post_zygote_collector_type_); 361 } else { 362 TransitionCollector(background_collector_type_); 363 } 364 } else { 365 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 366 } 367} 368 369void Heap::CreateThreadPool() { 370 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 371 if (num_threads != 0) { 372 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 373 } 374} 375 376void Heap::VisitObjects(ObjectCallback callback, void* arg) { 377 Thread* self = Thread::Current(); 378 // GCs can move objects, so don't allow this. 379 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 380 if (bump_pointer_space_ != nullptr) { 381 // Visit objects in bump pointer space. 382 bump_pointer_space_->Walk(callback, arg); 383 } 384 // TODO: Switch to standard begin and end to use ranged a based loop. 385 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 386 it < end; ++it) { 387 mirror::Object* obj = *it; 388 if (obj != nullptr && obj->GetClass() != nullptr) { 389 // Avoid the race condition caused by the object not yet being written into the allocation 390 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 391 // there can be nulls on the allocation stack. 392 callback(obj, arg); 393 } 394 } 395 GetLiveBitmap()->Walk(callback, arg); 396 self->EndAssertNoThreadSuspension(old_cause); 397} 398 399void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 400 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 401 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 402 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 403 // TODO: Generalize this to n bitmaps? 404 if (space1 == nullptr) { 405 DCHECK(space2 != nullptr); 406 space1 = space2; 407 } 408 if (space2 == nullptr) { 409 DCHECK(space1 != nullptr); 410 space2 = space1; 411 } 412 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 413 large_object_space_->GetLiveObjects(), stack); 414} 415 416void Heap::DeleteThreadPool() { 417 thread_pool_.reset(nullptr); 418} 419 420void Heap::AddSpace(space::Space* space, bool set_as_default) { 421 DCHECK(space != nullptr); 422 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 423 if (space->IsContinuousSpace()) { 424 DCHECK(!space->IsDiscontinuousSpace()); 425 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 426 // Continuous spaces don't necessarily have bitmaps. 427 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 428 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 429 if (live_bitmap != nullptr) { 430 DCHECK(mark_bitmap != nullptr); 431 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 432 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 433 } 434 continuous_spaces_.push_back(continuous_space); 435 if (set_as_default) { 436 if (continuous_space->IsDlMallocSpace()) { 437 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 438 } else if (continuous_space->IsRosAllocSpace()) { 439 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 440 } 441 } 442 // Ensure that spaces remain sorted in increasing order of start address. 443 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 444 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 445 return a->Begin() < b->Begin(); 446 }); 447 } else { 448 DCHECK(space->IsDiscontinuousSpace()); 449 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 450 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 451 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 452 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 453 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 454 discontinuous_spaces_.push_back(discontinuous_space); 455 } 456 if (space->IsAllocSpace()) { 457 alloc_spaces_.push_back(space->AsAllocSpace()); 458 } 459} 460 461void Heap::RemoveSpace(space::Space* space) { 462 DCHECK(space != nullptr); 463 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 464 if (space->IsContinuousSpace()) { 465 DCHECK(!space->IsDiscontinuousSpace()); 466 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 467 // Continuous spaces don't necessarily have bitmaps. 468 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 469 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 470 if (live_bitmap != nullptr) { 471 DCHECK(mark_bitmap != nullptr); 472 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 473 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 474 } 475 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 476 DCHECK(it != continuous_spaces_.end()); 477 continuous_spaces_.erase(it); 478 if (continuous_space == dlmalloc_space_) { 479 dlmalloc_space_ = nullptr; 480 } else if (continuous_space == rosalloc_space_) { 481 rosalloc_space_ = nullptr; 482 } 483 if (continuous_space == main_space_) { 484 main_space_ = nullptr; 485 } 486 } else { 487 DCHECK(space->IsDiscontinuousSpace()); 488 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 489 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 490 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 491 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 492 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 493 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 494 discontinuous_space); 495 DCHECK(it != discontinuous_spaces_.end()); 496 discontinuous_spaces_.erase(it); 497 } 498 if (space->IsAllocSpace()) { 499 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 500 DCHECK(it != alloc_spaces_.end()); 501 alloc_spaces_.erase(it); 502 } 503} 504 505void Heap::RegisterGCAllocation(size_t bytes) { 506 if (this != nullptr) { 507 gc_memory_overhead_.FetchAndAdd(bytes); 508 } 509} 510 511void Heap::RegisterGCDeAllocation(size_t bytes) { 512 if (this != nullptr) { 513 gc_memory_overhead_.FetchAndSub(bytes); 514 } 515} 516 517void Heap::DumpGcPerformanceInfo(std::ostream& os) { 518 // Dump cumulative timings. 519 os << "Dumping cumulative Gc timings\n"; 520 uint64_t total_duration = 0; 521 522 // Dump cumulative loggers for each GC type. 523 uint64_t total_paused_time = 0; 524 for (const auto& collector : garbage_collectors_) { 525 CumulativeLogger& logger = collector->GetCumulativeTimings(); 526 if (logger.GetTotalNs() != 0) { 527 os << Dumpable<CumulativeLogger>(logger); 528 const uint64_t total_ns = logger.GetTotalNs(); 529 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 530 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 531 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 532 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 533 Histogram<uint64_t>::CumulativeData cumulative_data; 534 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 535 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 536 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 537 << collector->GetName() << " freed: " << freed_objects 538 << " objects with total size " << PrettySize(freed_bytes) << "\n" 539 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 540 << PrettySize(freed_bytes / seconds) << "/s\n"; 541 total_duration += total_ns; 542 total_paused_time += total_pause_ns; 543 } 544 } 545 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 546 if (total_duration != 0) { 547 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 548 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 549 os << "Mean GC size throughput: " 550 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 551 os << "Mean GC object throughput: " 552 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 553 } 554 size_t total_objects_allocated = GetObjectsAllocatedEver(); 555 os << "Total number of allocations: " << total_objects_allocated << "\n"; 556 size_t total_bytes_allocated = GetBytesAllocatedEver(); 557 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 558 if (kMeasureAllocationTime) { 559 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 560 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 561 << "\n"; 562 } 563 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 564 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 565 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 566} 567 568Heap::~Heap() { 569 VLOG(heap) << "Starting ~Heap()"; 570 STLDeleteElements(&garbage_collectors_); 571 // If we don't reset then the mark stack complains in its destructor. 572 allocation_stack_->Reset(); 573 live_stack_->Reset(); 574 STLDeleteValues(&mod_union_tables_); 575 STLDeleteElements(&continuous_spaces_); 576 STLDeleteElements(&discontinuous_spaces_); 577 delete gc_complete_lock_; 578 VLOG(heap) << "Finished ~Heap()"; 579} 580 581space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 582 bool fail_ok) const { 583 for (const auto& space : continuous_spaces_) { 584 if (space->Contains(obj)) { 585 return space; 586 } 587 } 588 if (!fail_ok) { 589 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 590 } 591 return NULL; 592} 593 594space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 595 bool fail_ok) const { 596 for (const auto& space : discontinuous_spaces_) { 597 if (space->Contains(obj)) { 598 return space; 599 } 600 } 601 if (!fail_ok) { 602 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 603 } 604 return NULL; 605} 606 607space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 608 space::Space* result = FindContinuousSpaceFromObject(obj, true); 609 if (result != NULL) { 610 return result; 611 } 612 return FindDiscontinuousSpaceFromObject(obj, true); 613} 614 615struct SoftReferenceArgs { 616 IsMarkedCallback* is_marked_callback_; 617 MarkObjectCallback* mark_callback_; 618 void* arg_; 619}; 620 621mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 622 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 623 // TODO: Not preserve all soft references. 624 return args->mark_callback_(obj, args->arg_); 625} 626 627// Process reference class instances and schedule finalizations. 628void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 629 IsMarkedCallback* is_marked_callback, 630 MarkObjectCallback* mark_object_callback, 631 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 632 // Unless we are in the zygote or required to clear soft references with white references, 633 // preserve some white referents. 634 if (!clear_soft && !Runtime::Current()->IsZygote()) { 635 SoftReferenceArgs soft_reference_args; 636 soft_reference_args.is_marked_callback_ = is_marked_callback; 637 soft_reference_args.mark_callback_ = mark_object_callback; 638 soft_reference_args.arg_ = arg; 639 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 640 &soft_reference_args); 641 process_mark_stack_callback(arg); 642 } 643 timings.StartSplit("(Paused)ProcessReferences"); 644 // Clear all remaining soft and weak references with white referents. 645 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 646 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 647 timings.EndSplit(); 648 // Preserve all white objects with finalize methods and schedule them for finalization. 649 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 650 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 651 mark_object_callback, arg); 652 process_mark_stack_callback(arg); 653 timings.EndSplit(); 654 timings.StartSplit("(Paused)ProcessReferences"); 655 // Clear all f-reachable soft and weak references with white referents. 656 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 657 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 658 // Clear all phantom references with white referents. 659 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 660 // At this point all reference queues other than the cleared references should be empty. 661 DCHECK(soft_reference_queue_.IsEmpty()); 662 DCHECK(weak_reference_queue_.IsEmpty()); 663 DCHECK(finalizer_reference_queue_.IsEmpty()); 664 DCHECK(phantom_reference_queue_.IsEmpty()); 665 timings.EndSplit(); 666} 667 668bool Heap::IsEnqueued(mirror::Object* ref) const { 669 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 670 // will always be non-null. 671 return ref->GetFieldObject<mirror::Object>(GetReferencePendingNextOffset(), false) != nullptr; 672} 673 674bool Heap::IsEnqueuable(mirror::Object* ref) const { 675 DCHECK(ref != nullptr); 676 const mirror::Object* queue = 677 ref->GetFieldObject<mirror::Object>(GetReferenceQueueOffset(), false); 678 const mirror::Object* queue_next = 679 ref->GetFieldObject<mirror::Object>(GetReferenceQueueNextOffset(), false); 680 return queue != nullptr && queue_next == nullptr; 681} 682 683// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 684// marked, put it on the appropriate list in the heap for later processing. 685void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 686 IsMarkedCallback is_marked_callback, void* arg) { 687 DCHECK(klass != nullptr); 688 DCHECK(klass->IsReferenceClass()); 689 DCHECK(obj != nullptr); 690 mirror::Object* referent = GetReferenceReferent(obj); 691 if (referent != nullptr) { 692 mirror::Object* forward_address = is_marked_callback(referent, arg); 693 // Null means that the object is not currently marked. 694 if (forward_address == nullptr) { 695 Thread* self = Thread::Current(); 696 // TODO: Remove these locks, and use atomic stacks for storing references? 697 // We need to check that the references haven't already been enqueued since we can end up 698 // scanning the same reference multiple times due to dirty cards. 699 if (klass->IsSoftReferenceClass()) { 700 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 701 } else if (klass->IsWeakReferenceClass()) { 702 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 703 } else if (klass->IsFinalizerReferenceClass()) { 704 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 705 } else if (klass->IsPhantomReferenceClass()) { 706 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 707 } else { 708 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 709 << klass->GetAccessFlags(); 710 } 711 } else if (referent != forward_address) { 712 // Referent is already marked and we need to update it. 713 SetReferenceReferent(obj, forward_address); 714 } 715 } 716} 717 718space::ImageSpace* Heap::GetImageSpace() const { 719 for (const auto& space : continuous_spaces_) { 720 if (space->IsImageSpace()) { 721 return space->AsImageSpace(); 722 } 723 } 724 return NULL; 725} 726 727static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 728 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 729 if (used_bytes < chunk_size) { 730 size_t chunk_free_bytes = chunk_size - used_bytes; 731 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 732 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 733 } 734} 735 736void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 737 std::ostringstream oss; 738 size_t total_bytes_free = GetFreeMemory(); 739 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 740 << " free bytes"; 741 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 742 if (!large_object_allocation && total_bytes_free >= byte_count) { 743 size_t max_contiguous_allocation = 0; 744 for (const auto& space : continuous_spaces_) { 745 if (space->IsMallocSpace()) { 746 // To allow the Walk/InspectAll() to exclusively-lock the mutator 747 // lock, temporarily release the shared access to the mutator 748 // lock here by transitioning to the suspended state. 749 Locks::mutator_lock_->AssertSharedHeld(self); 750 self->TransitionFromRunnableToSuspended(kSuspended); 751 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 752 self->TransitionFromSuspendedToRunnable(); 753 Locks::mutator_lock_->AssertSharedHeld(self); 754 } 755 } 756 oss << "; failed due to fragmentation (largest possible contiguous allocation " 757 << max_contiguous_allocation << " bytes)"; 758 } 759 self->ThrowOutOfMemoryError(oss.str().c_str()); 760} 761 762void Heap::Trim() { 763 Thread* self = Thread::Current(); 764 { 765 // Need to do this before acquiring the locks since we don't want to get suspended while 766 // holding any locks. 767 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 768 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 769 // trimming. 770 MutexLock mu(self, *gc_complete_lock_); 771 // Ensure there is only one GC at a time. 772 WaitForGcToCompleteLocked(self); 773 collector_type_running_ = kCollectorTypeHeapTrim; 774 } 775 uint64_t start_ns = NanoTime(); 776 // Trim the managed spaces. 777 uint64_t total_alloc_space_allocated = 0; 778 uint64_t total_alloc_space_size = 0; 779 uint64_t managed_reclaimed = 0; 780 for (const auto& space : continuous_spaces_) { 781 if (space->IsMallocSpace()) { 782 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 783 total_alloc_space_size += alloc_space->Size(); 784 managed_reclaimed += alloc_space->Trim(); 785 } 786 } 787 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 788 bump_pointer_space_->Size(); 789 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 790 static_cast<float>(total_alloc_space_size); 791 uint64_t gc_heap_end_ns = NanoTime(); 792 // We never move things in the native heap, so we can finish the GC at this point. 793 FinishGC(self, collector::kGcTypeNone); 794 // Trim the native heap. 795 dlmalloc_trim(0); 796 size_t native_reclaimed = 0; 797 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 798 uint64_t end_ns = NanoTime(); 799 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 800 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 801 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 802 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 803 << "%."; 804} 805 806bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 807 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 808 // taking the lock. 809 if (obj == nullptr) { 810 return true; 811 } 812 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 813} 814 815bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 816 return FindContinuousSpaceFromObject(obj, true) != nullptr; 817} 818 819bool Heap::IsHeapAddress(const mirror::Object* obj) const { 820 // TODO: This might not work for large objects. 821 return FindSpaceFromObject(obj, true) != nullptr; 822} 823 824bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 825 bool search_live_stack, bool sorted) { 826 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 827 return false; 828 } 829 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 830 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 831 if (obj == klass) { 832 // This case happens for java.lang.Class. 833 return true; 834 } 835 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 836 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 837 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 838 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 839 return temp_space_->Contains(obj); 840 } 841 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 842 space::DiscontinuousSpace* d_space = NULL; 843 if (c_space != nullptr) { 844 if (c_space->GetLiveBitmap()->Test(obj)) { 845 return true; 846 } 847 } else { 848 d_space = FindDiscontinuousSpaceFromObject(obj, true); 849 if (d_space != nullptr) { 850 if (d_space->GetLiveObjects()->Test(obj)) { 851 return true; 852 } 853 } 854 } 855 // This is covering the allocation/live stack swapping that is done without mutators suspended. 856 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 857 if (i > 0) { 858 NanoSleep(MsToNs(10)); 859 } 860 if (search_allocation_stack) { 861 if (sorted) { 862 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 863 return true; 864 } 865 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 866 return true; 867 } 868 } 869 870 if (search_live_stack) { 871 if (sorted) { 872 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 873 return true; 874 } 875 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 876 return true; 877 } 878 } 879 } 880 // We need to check the bitmaps again since there is a race where we mark something as live and 881 // then clear the stack containing it. 882 if (c_space != nullptr) { 883 if (c_space->GetLiveBitmap()->Test(obj)) { 884 return true; 885 } 886 } else { 887 d_space = FindDiscontinuousSpaceFromObject(obj, true); 888 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 889 return true; 890 } 891 } 892 return false; 893} 894 895void Heap::DumpSpaces(std::ostream& stream) { 896 for (const auto& space : continuous_spaces_) { 897 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 898 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 899 stream << space << " " << *space << "\n"; 900 if (live_bitmap != nullptr) { 901 stream << live_bitmap << " " << *live_bitmap << "\n"; 902 } 903 if (mark_bitmap != nullptr) { 904 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 905 } 906 } 907 for (const auto& space : discontinuous_spaces_) { 908 stream << space << " " << *space << "\n"; 909 } 910} 911 912void Heap::VerifyObjectBody(mirror::Object* obj) { 913 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 914 return; 915 } 916 // Ignore early dawn of the universe verifications. 917 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 918 return; 919 } 920 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 921 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 922 mirror::Object::ClassOffset(), false); 923 CHECK(c != nullptr) << "Null class in object " << obj; 924 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 925 CHECK(VerifyClassClass(c)); 926 927 if (verify_object_mode_ > kVerifyObjectModeFast) { 928 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 929 if (!IsLiveObjectLocked(obj)) { 930 DumpSpaces(); 931 LOG(FATAL) << "Object is dead: " << obj; 932 } 933 } 934} 935 936void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 937 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 938} 939 940void Heap::VerifyHeap() { 941 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 942 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 943} 944 945void Heap::RecordFree(size_t freed_objects, size_t freed_bytes) { 946 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 947 num_bytes_allocated_.FetchAndSub(freed_bytes); 948 if (Runtime::Current()->HasStatsEnabled()) { 949 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 950 thread_stats->freed_objects += freed_objects; 951 thread_stats->freed_bytes += freed_bytes; 952 // TODO: Do this concurrently. 953 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 954 global_stats->freed_objects += freed_objects; 955 global_stats->freed_bytes += freed_bytes; 956 } 957} 958 959mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 960 size_t alloc_size, size_t* bytes_allocated, 961 size_t* usable_size, 962 mirror::Class** klass) { 963 mirror::Object* ptr = nullptr; 964 bool was_default_allocator = allocator == GetCurrentAllocator(); 965 DCHECK(klass != nullptr); 966 SirtRef<mirror::Class> sirt_klass(self, *klass); 967 // The allocation failed. If the GC is running, block until it completes, and then retry the 968 // allocation. 969 collector::GcType last_gc = WaitForGcToComplete(self); 970 if (last_gc != collector::kGcTypeNone) { 971 // If we were the default allocator but the allocator changed while we were suspended, 972 // abort the allocation. 973 if (was_default_allocator && allocator != GetCurrentAllocator()) { 974 *klass = sirt_klass.get(); 975 return nullptr; 976 } 977 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 978 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 979 } 980 981 // Loop through our different Gc types and try to Gc until we get enough free memory. 982 for (collector::GcType gc_type : gc_plan_) { 983 if (ptr != nullptr) { 984 break; 985 } 986 // Attempt to run the collector, if we succeed, re-try the allocation. 987 bool gc_ran = 988 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 989 if (was_default_allocator && allocator != GetCurrentAllocator()) { 990 *klass = sirt_klass.get(); 991 return nullptr; 992 } 993 if (gc_ran) { 994 // Did we free sufficient memory for the allocation to succeed? 995 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 996 } 997 } 998 // Allocations have failed after GCs; this is an exceptional state. 999 if (ptr == nullptr) { 1000 // Try harder, growing the heap if necessary. 1001 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1002 } 1003 if (ptr == nullptr) { 1004 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1005 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1006 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1007 // OOME. 1008 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1009 << " allocation"; 1010 // TODO: Run finalization, but this may cause more allocations to occur. 1011 // We don't need a WaitForGcToComplete here either. 1012 DCHECK(!gc_plan_.empty()); 1013 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1014 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1015 *klass = sirt_klass.get(); 1016 return nullptr; 1017 } 1018 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1019 if (ptr == nullptr) { 1020 ThrowOutOfMemoryError(self, alloc_size, false); 1021 } 1022 } 1023 *klass = sirt_klass.get(); 1024 return ptr; 1025} 1026 1027void Heap::SetTargetHeapUtilization(float target) { 1028 DCHECK_GT(target, 0.0f); // asserted in Java code 1029 DCHECK_LT(target, 1.0f); 1030 target_utilization_ = target; 1031} 1032 1033size_t Heap::GetObjectsAllocated() const { 1034 size_t total = 0; 1035 for (space::AllocSpace* space : alloc_spaces_) { 1036 total += space->GetObjectsAllocated(); 1037 } 1038 return total; 1039} 1040 1041size_t Heap::GetObjectsAllocatedEver() const { 1042 return GetObjectsFreedEver() + GetObjectsAllocated(); 1043} 1044 1045size_t Heap::GetBytesAllocatedEver() const { 1046 return GetBytesFreedEver() + GetBytesAllocated(); 1047} 1048 1049class InstanceCounter { 1050 public: 1051 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1052 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1053 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1054 } 1055 static void Callback(mirror::Object* obj, void* arg) 1056 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1057 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1058 mirror::Class* instance_class = obj->GetClass(); 1059 CHECK(instance_class != nullptr); 1060 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1061 if (instance_counter->use_is_assignable_from_) { 1062 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1063 ++instance_counter->counts_[i]; 1064 } 1065 } else if (instance_class == instance_counter->classes_[i]) { 1066 ++instance_counter->counts_[i]; 1067 } 1068 } 1069 } 1070 1071 private: 1072 const std::vector<mirror::Class*>& classes_; 1073 bool use_is_assignable_from_; 1074 uint64_t* const counts_; 1075 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1076}; 1077 1078void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1079 uint64_t* counts) { 1080 // Can't do any GC in this function since this may move classes. 1081 Thread* self = Thread::Current(); 1082 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1083 InstanceCounter counter(classes, use_is_assignable_from, counts); 1084 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1085 VisitObjects(InstanceCounter::Callback, &counter); 1086 self->EndAssertNoThreadSuspension(old_cause); 1087} 1088 1089class InstanceCollector { 1090 public: 1091 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1092 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1093 : class_(c), max_count_(max_count), instances_(instances) { 1094 } 1095 static void Callback(mirror::Object* obj, void* arg) 1096 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1097 DCHECK(arg != nullptr); 1098 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1099 mirror::Class* instance_class = obj->GetClass(); 1100 if (instance_class == instance_collector->class_) { 1101 if (instance_collector->max_count_ == 0 || 1102 instance_collector->instances_.size() < instance_collector->max_count_) { 1103 instance_collector->instances_.push_back(obj); 1104 } 1105 } 1106 } 1107 1108 private: 1109 mirror::Class* class_; 1110 uint32_t max_count_; 1111 std::vector<mirror::Object*>& instances_; 1112 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1113}; 1114 1115void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1116 std::vector<mirror::Object*>& instances) { 1117 // Can't do any GC in this function since this may move classes. 1118 Thread* self = Thread::Current(); 1119 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1120 InstanceCollector collector(c, max_count, instances); 1121 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1122 VisitObjects(&InstanceCollector::Callback, &collector); 1123 self->EndAssertNoThreadSuspension(old_cause); 1124} 1125 1126class ReferringObjectsFinder { 1127 public: 1128 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1129 std::vector<mirror::Object*>& referring_objects) 1130 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1131 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1132 } 1133 1134 static void Callback(mirror::Object* obj, void* arg) 1135 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1136 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1137 } 1138 1139 // For bitmap Visit. 1140 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1141 // annotalysis on visitors. 1142 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1143 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1144 } 1145 1146 // For MarkSweep::VisitObjectReferences. 1147 void operator()(mirror::Object* referrer, mirror::Object* object, 1148 const MemberOffset&, bool) const { 1149 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1150 referring_objects_.push_back(referrer); 1151 } 1152 } 1153 1154 private: 1155 mirror::Object* object_; 1156 uint32_t max_count_; 1157 std::vector<mirror::Object*>& referring_objects_; 1158 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1159}; 1160 1161void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1162 std::vector<mirror::Object*>& referring_objects) { 1163 // Can't do any GC in this function since this may move the object o. 1164 Thread* self = Thread::Current(); 1165 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1166 ReferringObjectsFinder finder(o, max_count, referring_objects); 1167 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1168 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1169 self->EndAssertNoThreadSuspension(old_cause); 1170} 1171 1172void Heap::CollectGarbage(bool clear_soft_references) { 1173 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1174 // last GC will not have necessarily been cleared. 1175 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1176} 1177 1178void Heap::TransitionCollector(CollectorType collector_type) { 1179 if (collector_type == collector_type_) { 1180 return; 1181 } 1182 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1183 << " -> " << static_cast<int>(collector_type); 1184 uint64_t start_time = NanoTime(); 1185 uint32_t before_size = GetTotalMemory(); 1186 uint32_t before_allocated = num_bytes_allocated_.Load(); 1187 ThreadList* tl = Runtime::Current()->GetThreadList(); 1188 Thread* self = Thread::Current(); 1189 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1190 Locks::mutator_lock_->AssertNotHeld(self); 1191 const bool copying_transition = 1192 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1193 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1194 // compacting_gc_disable_count_, this should rarely occurs). 1195 for (;;) { 1196 { 1197 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1198 MutexLock mu(self, *gc_complete_lock_); 1199 // Ensure there is only one GC at a time. 1200 WaitForGcToCompleteLocked(self); 1201 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1202 if (!copying_transition || disable_moving_gc_count_ == 0) { 1203 // TODO: Not hard code in semi-space collector? 1204 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1205 break; 1206 } 1207 } 1208 usleep(1000); 1209 } 1210 tl->SuspendAll(); 1211 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1212 switch (collector_type) { 1213 case kCollectorTypeSS: 1214 // Fall-through. 1215 case kCollectorTypeGSS: { 1216 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1217 CHECK(main_space_ != nullptr); 1218 Compact(temp_space_, main_space_); 1219 DCHECK(allocator_mem_map_.get() == nullptr); 1220 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1221 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1222 // RemoveSpace does not delete the removed space. 1223 space::Space* old_space = main_space_; 1224 RemoveSpace(old_space); 1225 delete old_space; 1226 break; 1227 } 1228 case kCollectorTypeMS: 1229 // Fall through. 1230 case kCollectorTypeCMS: { 1231 if (IsCompactingGC(collector_type_)) { 1232 // TODO: Use mem-map from temp space? 1233 MemMap* mem_map = allocator_mem_map_.release(); 1234 CHECK(mem_map != nullptr); 1235 size_t initial_size = kDefaultInitialSize; 1236 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1237 CHECK(main_space_ == nullptr); 1238 if (kUseRosAlloc) { 1239 main_space_ = 1240 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1241 initial_size, mem_map->Size(), 1242 mem_map->Size(), low_memory_mode_); 1243 } else { 1244 main_space_ = 1245 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1246 initial_size, mem_map->Size(), 1247 mem_map->Size()); 1248 } 1249 main_space_->SetFootprintLimit(main_space_->Capacity()); 1250 AddSpace(main_space_); 1251 Compact(main_space_, bump_pointer_space_); 1252 } 1253 break; 1254 } 1255 default: { 1256 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1257 break; 1258 } 1259 } 1260 ChangeCollector(collector_type); 1261 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1262 tl->ResumeAll(); 1263 // Can't call into java code with all threads suspended. 1264 EnqueueClearedReferences(); 1265 uint64_t duration = NanoTime() - start_time; 1266 GrowForUtilization(collector::kGcTypeFull, duration); 1267 FinishGC(self, collector::kGcTypeFull); 1268 int32_t after_size = GetTotalMemory(); 1269 int32_t delta_size = before_size - after_size; 1270 int32_t after_allocated = num_bytes_allocated_.Load(); 1271 int32_t delta_allocated = before_allocated - after_allocated; 1272 const std::string saved_bytes_str = 1273 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1274 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1275 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1276 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1277 << PrettySize(delta_size) << " saved"; 1278} 1279 1280void Heap::ChangeCollector(CollectorType collector_type) { 1281 // TODO: Only do this with all mutators suspended to avoid races. 1282 if (collector_type != collector_type_) { 1283 collector_type_ = collector_type; 1284 gc_plan_.clear(); 1285 switch (collector_type_) { 1286 case kCollectorTypeSS: 1287 // Fall-through. 1288 case kCollectorTypeGSS: { 1289 concurrent_gc_ = false; 1290 gc_plan_.push_back(collector::kGcTypeFull); 1291 if (use_tlab_) { 1292 ChangeAllocator(kAllocatorTypeTLAB); 1293 } else { 1294 ChangeAllocator(kAllocatorTypeBumpPointer); 1295 } 1296 break; 1297 } 1298 case kCollectorTypeMS: { 1299 concurrent_gc_ = false; 1300 gc_plan_.push_back(collector::kGcTypeSticky); 1301 gc_plan_.push_back(collector::kGcTypePartial); 1302 gc_plan_.push_back(collector::kGcTypeFull); 1303 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1304 break; 1305 } 1306 case kCollectorTypeCMS: { 1307 concurrent_gc_ = true; 1308 gc_plan_.push_back(collector::kGcTypeSticky); 1309 gc_plan_.push_back(collector::kGcTypePartial); 1310 gc_plan_.push_back(collector::kGcTypeFull); 1311 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1312 break; 1313 } 1314 default: { 1315 LOG(FATAL) << "Unimplemented"; 1316 } 1317 } 1318 if (concurrent_gc_) { 1319 concurrent_start_bytes_ = 1320 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1321 } else { 1322 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1323 } 1324 } 1325} 1326 1327// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1328class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1329 public: 1330 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector"), 1331 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1332 } 1333 1334 void BuildBins(space::ContinuousSpace* space) { 1335 bin_live_bitmap_ = space->GetLiveBitmap(); 1336 bin_mark_bitmap_ = space->GetMarkBitmap(); 1337 BinContext context; 1338 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1339 context.collector_ = this; 1340 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1341 // Note: This requires traversing the space in increasing order of object addresses. 1342 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1343 // Add the last bin which spans after the last object to the end of the space. 1344 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1345 } 1346 1347 private: 1348 struct BinContext { 1349 uintptr_t prev_; // The end of the previous object. 1350 ZygoteCompactingCollector* collector_; 1351 }; 1352 // Maps from bin sizes to locations. 1353 std::multimap<size_t, uintptr_t> bins_; 1354 // Live bitmap of the space which contains the bins. 1355 accounting::SpaceBitmap* bin_live_bitmap_; 1356 // Mark bitmap of the space which contains the bins. 1357 accounting::SpaceBitmap* bin_mark_bitmap_; 1358 1359 static void Callback(mirror::Object* obj, void* arg) 1360 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1361 DCHECK(arg != nullptr); 1362 BinContext* context = reinterpret_cast<BinContext*>(arg); 1363 ZygoteCompactingCollector* collector = context->collector_; 1364 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1365 size_t bin_size = object_addr - context->prev_; 1366 // Add the bin consisting of the end of the previous object to the start of the current object. 1367 collector->AddBin(bin_size, context->prev_); 1368 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1369 } 1370 1371 void AddBin(size_t size, uintptr_t position) { 1372 if (size != 0) { 1373 bins_.insert(std::make_pair(size, position)); 1374 } 1375 } 1376 1377 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1378 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1379 // allocator. 1380 return false; 1381 } 1382 1383 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1384 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1385 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1386 mirror::Object* forward_address; 1387 // Find the smallest bin which we can move obj in. 1388 auto it = bins_.lower_bound(object_size); 1389 if (it == bins_.end()) { 1390 // No available space in the bins, place it in the target space instead (grows the zygote 1391 // space). 1392 size_t bytes_allocated; 1393 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1394 if (to_space_live_bitmap_ != nullptr) { 1395 to_space_live_bitmap_->Set(forward_address); 1396 } else { 1397 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1398 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1399 } 1400 } else { 1401 size_t size = it->first; 1402 uintptr_t pos = it->second; 1403 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1404 forward_address = reinterpret_cast<mirror::Object*>(pos); 1405 // Set the live and mark bits so that sweeping system weaks works properly. 1406 bin_live_bitmap_->Set(forward_address); 1407 bin_mark_bitmap_->Set(forward_address); 1408 DCHECK_GE(size, object_size); 1409 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1410 } 1411 // Copy the object over to its new location. 1412 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1413 if (kUseBrooksPointer) { 1414 obj->AssertSelfBrooksPointer(); 1415 DCHECK_EQ(forward_address->GetBrooksPointer(), obj); 1416 forward_address->SetBrooksPointer(forward_address); 1417 forward_address->AssertSelfBrooksPointer(); 1418 } 1419 return forward_address; 1420 } 1421}; 1422 1423void Heap::UnBindBitmaps() { 1424 for (const auto& space : GetContinuousSpaces()) { 1425 if (space->IsContinuousMemMapAllocSpace()) { 1426 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1427 if (alloc_space->HasBoundBitmaps()) { 1428 alloc_space->UnBindBitmaps(); 1429 } 1430 } 1431 } 1432} 1433 1434void Heap::PreZygoteFork() { 1435 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1436 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1437 Thread* self = Thread::Current(); 1438 MutexLock mu(self, zygote_creation_lock_); 1439 // Try to see if we have any Zygote spaces. 1440 if (have_zygote_space_) { 1441 return; 1442 } 1443 VLOG(heap) << "Starting PreZygoteFork"; 1444 // Trim the pages at the end of the non moving space. 1445 non_moving_space_->Trim(); 1446 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1447 // Change the collector to the post zygote one. 1448 ChangeCollector(post_zygote_collector_type_); 1449 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1450 if (semi_space_collector_ != nullptr) { 1451 // Temporarily disable rosalloc verification because the zygote 1452 // compaction will mess up the rosalloc internal metadata. 1453 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1454 ZygoteCompactingCollector zygote_collector(this); 1455 zygote_collector.BuildBins(non_moving_space_); 1456 // Create a new bump pointer space which we will compact into. 1457 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1458 non_moving_space_->Limit()); 1459 // Compact the bump pointer space to a new zygote bump pointer space. 1460 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1461 zygote_collector.SetFromSpace(bump_pointer_space_); 1462 zygote_collector.SetToSpace(&target_space); 1463 zygote_collector.Run(kGcCauseCollectorTransition, false); 1464 CHECK(temp_space_->IsEmpty()); 1465 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1466 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1467 // Update the end and write out image. 1468 non_moving_space_->SetEnd(target_space.End()); 1469 non_moving_space_->SetLimit(target_space.Limit()); 1470 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1471 } 1472 // Save the old space so that we can remove it after we complete creating the zygote space. 1473 space::MallocSpace* old_alloc_space = non_moving_space_; 1474 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1475 // the remaining available space. 1476 // Remove the old space before creating the zygote space since creating the zygote space sets 1477 // the old alloc space's bitmaps to nullptr. 1478 RemoveSpace(old_alloc_space); 1479 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1480 low_memory_mode_, 1481 &main_space_); 1482 delete old_alloc_space; 1483 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1484 AddSpace(zygote_space, false); 1485 CHECK(main_space_ != nullptr); 1486 if (main_space_->IsRosAllocSpace()) { 1487 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1488 } else if (main_space_->IsDlMallocSpace()) { 1489 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1490 } 1491 main_space_->SetFootprintLimit(main_space_->Capacity()); 1492 AddSpace(main_space_); 1493 have_zygote_space_ = true; 1494 // Enable large object space allocations. 1495 large_object_threshold_ = kDefaultLargeObjectThreshold; 1496 // Create the zygote space mod union table. 1497 accounting::ModUnionTable* mod_union_table = 1498 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1499 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1500 AddModUnionTable(mod_union_table); 1501 // Can't use RosAlloc for non moving space due to thread local buffers. 1502 // TODO: Non limited space for non-movable objects? 1503 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1504 space::MallocSpace* new_non_moving_space = 1505 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1506 2 * MB, mem_map->Size(), mem_map->Size()); 1507 AddSpace(new_non_moving_space, false); 1508 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1509 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1510 non_moving_space_ = new_non_moving_space; 1511} 1512 1513void Heap::FlushAllocStack() { 1514 MarkAllocStackAsLive(allocation_stack_.get()); 1515 allocation_stack_->Reset(); 1516} 1517 1518void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1519 accounting::SpaceBitmap* bitmap2, 1520 accounting::ObjectSet* large_objects, 1521 accounting::ObjectStack* stack) { 1522 DCHECK(bitmap1 != nullptr); 1523 DCHECK(bitmap2 != nullptr); 1524 mirror::Object** limit = stack->End(); 1525 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1526 const mirror::Object* obj = *it; 1527 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1528 if (bitmap1->HasAddress(obj)) { 1529 bitmap1->Set(obj); 1530 } else if (bitmap2->HasAddress(obj)) { 1531 bitmap2->Set(obj); 1532 } else { 1533 large_objects->Set(obj); 1534 } 1535 } 1536 } 1537} 1538 1539void Heap::SwapSemiSpaces() { 1540 // Swap the spaces so we allocate into the space which we just evacuated. 1541 std::swap(bump_pointer_space_, temp_space_); 1542} 1543 1544void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1545 space::ContinuousMemMapAllocSpace* source_space) { 1546 CHECK(kMovingCollector); 1547 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1548 if (target_space != source_space) { 1549 semi_space_collector_->SetFromSpace(source_space); 1550 semi_space_collector_->SetToSpace(target_space); 1551 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1552 } 1553} 1554 1555collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1556 bool clear_soft_references) { 1557 Thread* self = Thread::Current(); 1558 Runtime* runtime = Runtime::Current(); 1559 // If the heap can't run the GC, silently fail and return that no GC was run. 1560 switch (gc_type) { 1561 case collector::kGcTypePartial: { 1562 if (!have_zygote_space_) { 1563 return collector::kGcTypeNone; 1564 } 1565 break; 1566 } 1567 default: { 1568 // Other GC types don't have any special cases which makes them not runnable. The main case 1569 // here is full GC. 1570 } 1571 } 1572 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1573 Locks::mutator_lock_->AssertNotHeld(self); 1574 if (self->IsHandlingStackOverflow()) { 1575 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1576 } 1577 bool compacting_gc; 1578 { 1579 gc_complete_lock_->AssertNotHeld(self); 1580 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1581 MutexLock mu(self, *gc_complete_lock_); 1582 // Ensure there is only one GC at a time. 1583 WaitForGcToCompleteLocked(self); 1584 compacting_gc = IsCompactingGC(collector_type_); 1585 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1586 if (compacting_gc && disable_moving_gc_count_ != 0) { 1587 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1588 return collector::kGcTypeNone; 1589 } 1590 collector_type_running_ = collector_type_; 1591 } 1592 1593 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1594 ++runtime->GetStats()->gc_for_alloc_count; 1595 ++self->GetStats()->gc_for_alloc_count; 1596 } 1597 uint64_t gc_start_time_ns = NanoTime(); 1598 uint64_t gc_start_size = GetBytesAllocated(); 1599 // Approximate allocation rate in bytes / second. 1600 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1601 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1602 if (LIKELY(ms_delta != 0)) { 1603 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1604 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1605 } 1606 1607 DCHECK_LT(gc_type, collector::kGcTypeMax); 1608 DCHECK_NE(gc_type, collector::kGcTypeNone); 1609 1610 collector::GarbageCollector* collector = nullptr; 1611 // TODO: Clean this up. 1612 if (compacting_gc) { 1613 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1614 current_allocator_ == kAllocatorTypeTLAB); 1615 gc_type = semi_space_collector_->GetGcType(); 1616 CHECK(temp_space_->IsEmpty()); 1617 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1618 semi_space_collector_->SetToSpace(temp_space_); 1619 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1620 collector = semi_space_collector_; 1621 gc_type = collector::kGcTypeFull; 1622 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1623 current_allocator_ == kAllocatorTypeDlMalloc) { 1624 for (const auto& cur_collector : garbage_collectors_) { 1625 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1626 cur_collector->GetGcType() == gc_type) { 1627 collector = cur_collector; 1628 break; 1629 } 1630 } 1631 } else { 1632 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1633 } 1634 CHECK(collector != nullptr) 1635 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1636 << " and type=" << gc_type; 1637 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1638 collector->Run(gc_cause, clear_soft_references); 1639 total_objects_freed_ever_ += collector->GetFreedObjects(); 1640 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1641 // Enqueue cleared references. 1642 EnqueueClearedReferences(); 1643 // Grow the heap so that we know when to perform the next GC. 1644 GrowForUtilization(gc_type, collector->GetDurationNs()); 1645 if (CareAboutPauseTimes()) { 1646 const size_t duration = collector->GetDurationNs(); 1647 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1648 // GC for alloc pauses the allocating thread, so consider it as a pause. 1649 bool was_slow = duration > long_gc_log_threshold_ || 1650 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1651 if (!was_slow) { 1652 for (uint64_t pause : pauses) { 1653 was_slow = was_slow || pause > long_pause_log_threshold_; 1654 } 1655 } 1656 if (was_slow) { 1657 const size_t percent_free = GetPercentFree(); 1658 const size_t current_heap_size = GetBytesAllocated(); 1659 const size_t total_memory = GetTotalMemory(); 1660 std::ostringstream pause_string; 1661 for (size_t i = 0; i < pauses.size(); ++i) { 1662 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1663 << ((i != pauses.size() - 1) ? ", " : ""); 1664 } 1665 LOG(INFO) << gc_cause << " " << collector->GetName() 1666 << " GC freed " << collector->GetFreedObjects() << "(" 1667 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1668 << collector->GetFreedLargeObjects() << "(" 1669 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1670 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1671 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1672 << " total " << PrettyDuration((duration / 1000) * 1000); 1673 if (VLOG_IS_ON(heap)) { 1674 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1675 } 1676 } 1677 } 1678 FinishGC(self, gc_type); 1679 ATRACE_END(); 1680 1681 // Inform DDMS that a GC completed. 1682 Dbg::GcDidFinish(); 1683 return gc_type; 1684} 1685 1686void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1687 MutexLock mu(self, *gc_complete_lock_); 1688 collector_type_running_ = kCollectorTypeNone; 1689 if (gc_type != collector::kGcTypeNone) { 1690 last_gc_type_ = gc_type; 1691 } 1692 // Wake anyone who may have been waiting for the GC to complete. 1693 gc_complete_cond_->Broadcast(self); 1694} 1695 1696static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1697 RootType /*root_type*/) { 1698 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1699 if (*root == obj) { 1700 LOG(INFO) << "Object " << obj << " is a root"; 1701 } 1702} 1703 1704class ScanVisitor { 1705 public: 1706 void operator()(const mirror::Object* obj) const { 1707 LOG(ERROR) << "Would have rescanned object " << obj; 1708 } 1709}; 1710 1711// Verify a reference from an object. 1712class VerifyReferenceVisitor { 1713 public: 1714 explicit VerifyReferenceVisitor(Heap* heap) 1715 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1716 : heap_(heap), failed_(false) {} 1717 1718 bool Failed() const { 1719 return failed_; 1720 } 1721 1722 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1723 // analysis on visitors. 1724 void operator()(mirror::Object* obj, mirror::Object* ref, 1725 const MemberOffset& offset, bool /* is_static */) const 1726 NO_THREAD_SAFETY_ANALYSIS { 1727 if (ref == nullptr || IsLive(ref)) { 1728 // Verify that the reference is live. 1729 return; 1730 } 1731 if (!failed_) { 1732 // Print message on only on first failure to prevent spam. 1733 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1734 failed_ = true; 1735 } 1736 if (obj != nullptr) { 1737 accounting::CardTable* card_table = heap_->GetCardTable(); 1738 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1739 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1740 byte* card_addr = card_table->CardFromAddr(obj); 1741 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1742 << offset << "\n card value = " << static_cast<int>(*card_addr); 1743 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1744 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1745 } else { 1746 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1747 } 1748 1749 // Attmept to find the class inside of the recently freed objects. 1750 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1751 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1752 space::MallocSpace* space = ref_space->AsMallocSpace(); 1753 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1754 if (ref_class != nullptr) { 1755 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1756 << PrettyClass(ref_class); 1757 } else { 1758 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1759 } 1760 } 1761 1762 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1763 ref->GetClass()->IsClass()) { 1764 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1765 } else { 1766 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1767 << ") is not a valid heap address"; 1768 } 1769 1770 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1771 void* cover_begin = card_table->AddrFromCard(card_addr); 1772 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1773 accounting::CardTable::kCardSize); 1774 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1775 << "-" << cover_end; 1776 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1777 1778 if (bitmap == nullptr) { 1779 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1780 if (!VerifyClassClass(obj->GetClass())) { 1781 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1782 } 1783 } else { 1784 // Print out how the object is live. 1785 if (bitmap->Test(obj)) { 1786 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1787 } 1788 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1789 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1790 } 1791 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1792 LOG(ERROR) << "Object " << obj << " found in live stack"; 1793 } 1794 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1795 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1796 } 1797 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1798 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1799 } 1800 // Attempt to see if the card table missed the reference. 1801 ScanVisitor scan_visitor; 1802 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1803 card_table->Scan(bitmap, byte_cover_begin, 1804 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1805 } 1806 1807 // Search to see if any of the roots reference our object. 1808 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1809 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1810 1811 // Search to see if any of the roots reference our reference. 1812 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1813 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1814 } else { 1815 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 1816 } 1817 } 1818 1819 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1820 return heap_->IsLiveObjectLocked(obj, true, false, true); 1821 } 1822 1823 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1824 RootType /*root_type*/) { 1825 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1826 (*visitor)(nullptr, *root, MemberOffset(0), true); 1827 } 1828 1829 private: 1830 Heap* const heap_; 1831 mutable bool failed_; 1832}; 1833 1834// Verify all references within an object, for use with HeapBitmap::Visit. 1835class VerifyObjectVisitor { 1836 public: 1837 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1838 1839 void operator()(mirror::Object* obj) const 1840 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1841 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1842 // be live or else how did we find it in the live bitmap? 1843 VerifyReferenceVisitor visitor(heap_); 1844 // The class doesn't count as a reference but we should verify it anyways. 1845 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1846 if (obj->GetClass()->IsReferenceClass()) { 1847 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1848 } 1849 failed_ = failed_ || visitor.Failed(); 1850 } 1851 1852 static void VisitCallback(mirror::Object* obj, void* arg) 1853 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1854 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1855 visitor->operator()(obj); 1856 } 1857 1858 bool Failed() const { 1859 return failed_; 1860 } 1861 1862 private: 1863 Heap* const heap_; 1864 mutable bool failed_; 1865}; 1866 1867// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1868bool Heap::VerifyHeapReferences() { 1869 Thread* self = Thread::Current(); 1870 Locks::mutator_lock_->AssertExclusiveHeld(self); 1871 // Lets sort our allocation stacks so that we can efficiently binary search them. 1872 allocation_stack_->Sort(); 1873 live_stack_->Sort(); 1874 // Since we sorted the allocation stack content, need to revoke all 1875 // thread-local allocation stacks. 1876 RevokeAllThreadLocalAllocationStacks(self); 1877 VerifyObjectVisitor visitor(this); 1878 // Verify objects in the allocation stack since these will be objects which were: 1879 // 1. Allocated prior to the GC (pre GC verification). 1880 // 2. Allocated during the GC (pre sweep GC verification). 1881 // We don't want to verify the objects in the live stack since they themselves may be 1882 // pointing to dead objects if they are not reachable. 1883 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1884 // Verify the roots: 1885 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1886 if (visitor.Failed()) { 1887 // Dump mod-union tables. 1888 for (const auto& table_pair : mod_union_tables_) { 1889 accounting::ModUnionTable* mod_union_table = table_pair.second; 1890 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1891 } 1892 DumpSpaces(); 1893 return false; 1894 } 1895 return true; 1896} 1897 1898class VerifyReferenceCardVisitor { 1899 public: 1900 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1901 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1902 Locks::heap_bitmap_lock_) 1903 : heap_(heap), failed_(failed) { 1904 } 1905 1906 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1907 // annotalysis on visitors. 1908 void operator()(mirror::Object* obj, mirror::Object* ref, const MemberOffset& offset, 1909 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1910 // Filter out class references since changing an object's class does not mark the card as dirty. 1911 // Also handles large objects, since the only reference they hold is a class reference. 1912 if (ref != NULL && !ref->IsClass()) { 1913 accounting::CardTable* card_table = heap_->GetCardTable(); 1914 // If the object is not dirty and it is referencing something in the live stack other than 1915 // class, then it must be on a dirty card. 1916 if (!card_table->AddrIsInCardTable(obj)) { 1917 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1918 *failed_ = true; 1919 } else if (!card_table->IsDirty(obj)) { 1920 // TODO: Check mod-union tables. 1921 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1922 // kCardDirty - 1 if it didnt get touched since we aged it. 1923 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1924 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1925 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1926 LOG(ERROR) << "Object " << obj << " found in live stack"; 1927 } 1928 if (heap_->GetLiveBitmap()->Test(obj)) { 1929 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1930 } 1931 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1932 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1933 1934 // Print which field of the object is dead. 1935 if (!obj->IsObjectArray()) { 1936 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1937 CHECK(klass != NULL); 1938 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1939 : klass->GetIFields(); 1940 CHECK(fields != NULL); 1941 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1942 mirror::ArtField* cur = fields->Get(i); 1943 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1944 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1945 << PrettyField(cur); 1946 break; 1947 } 1948 } 1949 } else { 1950 mirror::ObjectArray<mirror::Object>* object_array = 1951 obj->AsObjectArray<mirror::Object>(); 1952 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1953 if (object_array->Get(i) == ref) { 1954 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1955 } 1956 } 1957 } 1958 1959 *failed_ = true; 1960 } 1961 } 1962 } 1963 } 1964 1965 private: 1966 Heap* const heap_; 1967 bool* const failed_; 1968}; 1969 1970class VerifyLiveStackReferences { 1971 public: 1972 explicit VerifyLiveStackReferences(Heap* heap) 1973 : heap_(heap), 1974 failed_(false) {} 1975 1976 void operator()(mirror::Object* obj) const 1977 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1978 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1979 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1980 } 1981 1982 bool Failed() const { 1983 return failed_; 1984 } 1985 1986 private: 1987 Heap* const heap_; 1988 bool failed_; 1989}; 1990 1991bool Heap::VerifyMissingCardMarks() { 1992 Thread* self = Thread::Current(); 1993 Locks::mutator_lock_->AssertExclusiveHeld(self); 1994 1995 // We need to sort the live stack since we binary search it. 1996 live_stack_->Sort(); 1997 // Since we sorted the allocation stack content, need to revoke all 1998 // thread-local allocation stacks. 1999 RevokeAllThreadLocalAllocationStacks(self); 2000 VerifyLiveStackReferences visitor(this); 2001 GetLiveBitmap()->Visit(visitor); 2002 2003 // We can verify objects in the live stack since none of these should reference dead objects. 2004 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2005 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2006 visitor(*it); 2007 } 2008 } 2009 2010 if (visitor.Failed()) { 2011 DumpSpaces(); 2012 return false; 2013 } 2014 return true; 2015} 2016 2017void Heap::SwapStacks(Thread* self) { 2018 if (kUseThreadLocalAllocationStack) { 2019 live_stack_->AssertAllZero(); 2020 } 2021 allocation_stack_.swap(live_stack_); 2022} 2023 2024void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2025 // This must be called only during the pause. 2026 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2027 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2028 MutexLock mu2(self, *Locks::thread_list_lock_); 2029 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2030 for (Thread* t : thread_list) { 2031 t->RevokeThreadLocalAllocationStack(); 2032 } 2033} 2034 2035accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2036 auto it = mod_union_tables_.find(space); 2037 if (it == mod_union_tables_.end()) { 2038 return nullptr; 2039 } 2040 return it->second; 2041} 2042 2043void Heap::ProcessCards(TimingLogger& timings) { 2044 // Clear cards and keep track of cards cleared in the mod-union table. 2045 for (const auto& space : continuous_spaces_) { 2046 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2047 if (table != nullptr) { 2048 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2049 "ImageModUnionClearCards"; 2050 TimingLogger::ScopedSplit split(name, &timings); 2051 table->ClearCards(); 2052 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2053 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2054 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2055 // were dirty before the GC started. 2056 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2057 // -> clean(cleaning thread). 2058 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2059 // roots and then we scan / update mod union tables after. We will always scan either card. 2060 // If we end up with the non aged card, we scan it it in the pause. 2061 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2062 } 2063 } 2064} 2065 2066static mirror::Object* IdentityMarkObjectCallback(mirror::Object* obj, void*) { 2067 return obj; 2068} 2069 2070void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2071 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2072 Thread* self = Thread::Current(); 2073 2074 if (verify_pre_gc_heap_) { 2075 thread_list->SuspendAll(); 2076 { 2077 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2078 if (!VerifyHeapReferences()) { 2079 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2080 } 2081 } 2082 thread_list->ResumeAll(); 2083 } 2084 2085 // Check that all objects which reference things in the live stack are on dirty cards. 2086 if (verify_missing_card_marks_) { 2087 thread_list->SuspendAll(); 2088 { 2089 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2090 SwapStacks(self); 2091 // Sort the live stack so that we can quickly binary search it later. 2092 if (!VerifyMissingCardMarks()) { 2093 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2094 } 2095 SwapStacks(self); 2096 } 2097 thread_list->ResumeAll(); 2098 } 2099 2100 if (verify_mod_union_table_) { 2101 thread_list->SuspendAll(); 2102 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2103 for (const auto& table_pair : mod_union_tables_) { 2104 accounting::ModUnionTable* mod_union_table = table_pair.second; 2105 mod_union_table->UpdateAndMarkReferences(IdentityMarkObjectCallback, nullptr); 2106 mod_union_table->Verify(); 2107 } 2108 thread_list->ResumeAll(); 2109 } 2110} 2111 2112void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2113 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2114 // reachable objects. 2115 if (verify_post_gc_heap_) { 2116 Thread* self = Thread::Current(); 2117 CHECK_NE(self->GetState(), kRunnable); 2118 { 2119 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2120 // Swapping bound bitmaps does nothing. 2121 gc->SwapBitmaps(); 2122 if (!VerifyHeapReferences()) { 2123 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2124 } 2125 gc->SwapBitmaps(); 2126 } 2127 } 2128} 2129 2130void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2131 if (verify_system_weaks_) { 2132 Thread* self = Thread::Current(); 2133 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2134 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2135 mark_sweep->VerifySystemWeaks(); 2136 } 2137} 2138 2139void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2140 if (verify_pre_gc_rosalloc_) { 2141 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2142 for (const auto& space : continuous_spaces_) { 2143 if (space->IsRosAllocSpace()) { 2144 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2145 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2146 rosalloc_space->Verify(); 2147 } 2148 } 2149 } 2150} 2151 2152void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2153 if (verify_post_gc_rosalloc_) { 2154 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2155 for (const auto& space : continuous_spaces_) { 2156 if (space->IsRosAllocSpace()) { 2157 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2158 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2159 rosalloc_space->Verify(); 2160 } 2161 } 2162 } 2163} 2164 2165collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2166 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2167 MutexLock mu(self, *gc_complete_lock_); 2168 return WaitForGcToCompleteLocked(self); 2169} 2170 2171collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2172 collector::GcType last_gc_type = collector::kGcTypeNone; 2173 uint64_t wait_start = NanoTime(); 2174 while (collector_type_running_ != kCollectorTypeNone) { 2175 ATRACE_BEGIN("GC: Wait For Completion"); 2176 // We must wait, change thread state then sleep on gc_complete_cond_; 2177 gc_complete_cond_->Wait(self); 2178 last_gc_type = last_gc_type_; 2179 ATRACE_END(); 2180 } 2181 uint64_t wait_time = NanoTime() - wait_start; 2182 total_wait_time_ += wait_time; 2183 if (wait_time > long_pause_log_threshold_) { 2184 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2185 } 2186 return last_gc_type; 2187} 2188 2189void Heap::DumpForSigQuit(std::ostream& os) { 2190 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2191 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2192 DumpGcPerformanceInfo(os); 2193} 2194 2195size_t Heap::GetPercentFree() { 2196 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2197} 2198 2199void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2200 if (max_allowed_footprint > GetMaxMemory()) { 2201 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2202 << PrettySize(GetMaxMemory()); 2203 max_allowed_footprint = GetMaxMemory(); 2204 } 2205 max_allowed_footprint_ = max_allowed_footprint; 2206} 2207 2208bool Heap::IsMovableObject(const mirror::Object* obj) const { 2209 if (kMovingCollector) { 2210 DCHECK(!IsInTempSpace(obj)); 2211 if (bump_pointer_space_->HasAddress(obj)) { 2212 return true; 2213 } 2214 // TODO: Refactor this logic into the space itself? 2215 // Objects in the main space are only copied during background -> foreground transitions or 2216 // visa versa. 2217 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2218 (IsCompactingGC(background_collector_type_) || 2219 IsCompactingGC(post_zygote_collector_type_))) { 2220 return true; 2221 } 2222 } 2223 return false; 2224} 2225 2226bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2227 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2228 return true; 2229 } 2230 return false; 2231} 2232 2233void Heap::UpdateMaxNativeFootprint() { 2234 size_t native_size = native_bytes_allocated_; 2235 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2236 size_t target_size = native_size / GetTargetHeapUtilization(); 2237 if (target_size > native_size + max_free_) { 2238 target_size = native_size + max_free_; 2239 } else if (target_size < native_size + min_free_) { 2240 target_size = native_size + min_free_; 2241 } 2242 native_footprint_gc_watermark_ = target_size; 2243 native_footprint_limit_ = 2 * target_size - native_size; 2244} 2245 2246void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2247 // We know what our utilization is at this moment. 2248 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2249 const size_t bytes_allocated = GetBytesAllocated(); 2250 last_gc_size_ = bytes_allocated; 2251 last_gc_time_ns_ = NanoTime(); 2252 size_t target_size; 2253 if (gc_type != collector::kGcTypeSticky) { 2254 // Grow the heap for non sticky GC. 2255 target_size = bytes_allocated / GetTargetHeapUtilization(); 2256 if (target_size > bytes_allocated + max_free_) { 2257 target_size = bytes_allocated + max_free_; 2258 } else if (target_size < bytes_allocated + min_free_) { 2259 target_size = bytes_allocated + min_free_; 2260 } 2261 native_need_to_run_finalization_ = true; 2262 next_gc_type_ = collector::kGcTypeSticky; 2263 } else { 2264 // Based on how close the current heap size is to the target size, decide 2265 // whether or not to do a partial or sticky GC next. 2266 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2267 next_gc_type_ = collector::kGcTypeSticky; 2268 } else { 2269 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2270 } 2271 // If we have freed enough memory, shrink the heap back down. 2272 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2273 target_size = bytes_allocated + max_free_; 2274 } else { 2275 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2276 } 2277 } 2278 if (!ignore_max_footprint_) { 2279 SetIdealFootprint(target_size); 2280 if (concurrent_gc_) { 2281 // Calculate when to perform the next ConcurrentGC. 2282 // Calculate the estimated GC duration. 2283 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2284 // Estimate how many remaining bytes we will have when we need to start the next GC. 2285 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2286 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2287 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2288 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2289 // A never going to happen situation that from the estimated allocation rate we will exceed 2290 // the applications entire footprint with the given estimated allocation rate. Schedule 2291 // another GC nearly straight away. 2292 remaining_bytes = kMinConcurrentRemainingBytes; 2293 } 2294 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2295 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2296 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2297 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2298 // right away. 2299 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2300 } 2301 } 2302} 2303 2304void Heap::ClearGrowthLimit() { 2305 growth_limit_ = capacity_; 2306 non_moving_space_->ClearGrowthLimit(); 2307} 2308 2309void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2310 MemberOffset reference_queue_offset, 2311 MemberOffset reference_queueNext_offset, 2312 MemberOffset reference_pendingNext_offset, 2313 MemberOffset finalizer_reference_zombie_offset) { 2314 reference_referent_offset_ = reference_referent_offset; 2315 reference_queue_offset_ = reference_queue_offset; 2316 reference_queueNext_offset_ = reference_queueNext_offset; 2317 reference_pendingNext_offset_ = reference_pendingNext_offset; 2318 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2319 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2320 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2321 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2322 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2323 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2324} 2325 2326void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2327 DCHECK(reference != NULL); 2328 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2329 reference->SetFieldObject<false, false>(reference_referent_offset_, referent, true); 2330} 2331 2332mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2333 DCHECK(reference != NULL); 2334 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2335 return reference->GetFieldObject<mirror::Object>(reference_referent_offset_, true); 2336} 2337 2338void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2339 ScopedObjectAccess soa(self); 2340 JValue result; 2341 ArgArray arg_array("VL", 2); 2342 arg_array.Append(object); 2343 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2344 arg_array.GetArray(), arg_array.GetNumBytes(), &result, "VL"); 2345} 2346 2347void Heap::EnqueueClearedReferences() { 2348 Thread* self = Thread::Current(); 2349 Locks::mutator_lock_->AssertNotHeld(self); 2350 if (!cleared_references_.IsEmpty()) { 2351 // When a runtime isn't started there are no reference queues to care about so ignore. 2352 if (LIKELY(Runtime::Current()->IsStarted())) { 2353 ScopedObjectAccess soa(self); 2354 JValue result; 2355 ArgArray arg_array("VL", 2); 2356 arg_array.Append(cleared_references_.GetList()); 2357 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2358 arg_array.GetArray(), arg_array.GetNumBytes(), &result, "VL"); 2359 } 2360 cleared_references_.Clear(); 2361 } 2362} 2363 2364void Heap::RequestConcurrentGC(Thread* self) { 2365 // Make sure that we can do a concurrent GC. 2366 Runtime* runtime = Runtime::Current(); 2367 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2368 self->IsHandlingStackOverflow()) { 2369 return; 2370 } 2371 // We already have a request pending, no reason to start more until we update 2372 // concurrent_start_bytes_. 2373 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2374 JNIEnv* env = self->GetJniEnv(); 2375 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2376 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2377 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2378 WellKnownClasses::java_lang_Daemons_requestGC); 2379 CHECK(!env->ExceptionCheck()); 2380} 2381 2382void Heap::ConcurrentGC(Thread* self) { 2383 if (Runtime::Current()->IsShuttingDown(self)) { 2384 return; 2385 } 2386 // Wait for any GCs currently running to finish. 2387 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2388 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2389 // instead. E.g. can't do partial, so do full instead. 2390 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2391 collector::kGcTypeNone) { 2392 for (collector::GcType gc_type : gc_plan_) { 2393 // Attempt to run the collector, if we succeed, we are done. 2394 if (gc_type > next_gc_type_ && 2395 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2396 break; 2397 } 2398 } 2399 } 2400 } 2401} 2402 2403void Heap::RequestHeapTrim() { 2404 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2405 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2406 // a space it will hold its lock and can become a cause of jank. 2407 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2408 // forking. 2409 2410 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2411 // because that only marks object heads, so a large array looks like lots of empty space. We 2412 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2413 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2414 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2415 // not how much use we're making of those pages. 2416 uint64_t ms_time = MilliTime(); 2417 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2418 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2419 return; 2420 } 2421 2422 Thread* self = Thread::Current(); 2423 Runtime* runtime = Runtime::Current(); 2424 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2425 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2426 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2427 // as we don't hold the lock while requesting the trim). 2428 return; 2429 } 2430 2431 last_trim_time_ms_ = ms_time; 2432 2433 // Trim only if we do not currently care about pause times. 2434 if (!CareAboutPauseTimes()) { 2435 JNIEnv* env = self->GetJniEnv(); 2436 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2437 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2438 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2439 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2440 CHECK(!env->ExceptionCheck()); 2441 } 2442} 2443 2444void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2445 if (rosalloc_space_ != nullptr) { 2446 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2447 } 2448 if (bump_pointer_space_ != nullptr) { 2449 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2450 } 2451} 2452 2453void Heap::RevokeAllThreadLocalBuffers() { 2454 if (rosalloc_space_ != nullptr) { 2455 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2456 } 2457 if (bump_pointer_space_ != nullptr) { 2458 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2459 } 2460} 2461 2462bool Heap::IsGCRequestPending() const { 2463 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2464} 2465 2466void Heap::RunFinalization(JNIEnv* env) { 2467 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2468 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2469 CHECK(WellKnownClasses::java_lang_System != nullptr); 2470 WellKnownClasses::java_lang_System_runFinalization = 2471 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2472 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2473 } 2474 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2475 WellKnownClasses::java_lang_System_runFinalization); 2476} 2477 2478void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2479 Thread* self = ThreadForEnv(env); 2480 if (native_need_to_run_finalization_) { 2481 RunFinalization(env); 2482 UpdateMaxNativeFootprint(); 2483 native_need_to_run_finalization_ = false; 2484 } 2485 // Total number of native bytes allocated. 2486 native_bytes_allocated_.FetchAndAdd(bytes); 2487 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2488 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2489 collector::kGcTypeFull; 2490 2491 // The second watermark is higher than the gc watermark. If you hit this it means you are 2492 // allocating native objects faster than the GC can keep up with. 2493 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2494 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2495 // Just finished a GC, attempt to run finalizers. 2496 RunFinalization(env); 2497 CHECK(!env->ExceptionCheck()); 2498 } 2499 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2500 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2501 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2502 RunFinalization(env); 2503 native_need_to_run_finalization_ = false; 2504 CHECK(!env->ExceptionCheck()); 2505 } 2506 // We have just run finalizers, update the native watermark since it is very likely that 2507 // finalizers released native managed allocations. 2508 UpdateMaxNativeFootprint(); 2509 } else if (!IsGCRequestPending()) { 2510 if (concurrent_gc_) { 2511 RequestConcurrentGC(self); 2512 } else { 2513 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2514 } 2515 } 2516 } 2517} 2518 2519void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2520 int expected_size, new_size; 2521 do { 2522 expected_size = native_bytes_allocated_.Load(); 2523 new_size = expected_size - bytes; 2524 if (UNLIKELY(new_size < 0)) { 2525 ScopedObjectAccess soa(env); 2526 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2527 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2528 "registered as allocated", bytes, expected_size).c_str()); 2529 break; 2530 } 2531 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2532} 2533 2534size_t Heap::GetTotalMemory() const { 2535 size_t ret = 0; 2536 for (const auto& space : continuous_spaces_) { 2537 // Currently don't include the image space. 2538 if (!space->IsImageSpace()) { 2539 ret += space->Size(); 2540 } 2541 } 2542 for (const auto& space : discontinuous_spaces_) { 2543 if (space->IsLargeObjectSpace()) { 2544 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2545 } 2546 } 2547 return ret; 2548} 2549 2550void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2551 DCHECK(mod_union_table != nullptr); 2552 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2553} 2554 2555} // namespace gc 2556} // namespace art 2557