heap.cc revision ebdf3f320d71563cf0236c31d35d633be9576d8c
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 soft_reference_queue_(this), 102 weak_reference_queue_(this), 103 finalizer_reference_queue_(this), 104 phantom_reference_queue_(this), 105 cleared_references_(this), 106 collector_type_running_(kCollectorTypeNone), 107 last_gc_type_(collector::kGcTypeNone), 108 next_gc_type_(collector::kGcTypePartial), 109 capacity_(capacity), 110 growth_limit_(growth_limit), 111 max_allowed_footprint_(initial_size), 112 native_footprint_gc_watermark_(initial_size), 113 native_footprint_limit_(2 * initial_size), 114 native_need_to_run_finalization_(false), 115 // Initially assume we perceive jank in case the process state is never updated. 116 process_state_(kProcessStateJankPerceptible), 117 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 118 total_bytes_freed_ever_(0), 119 total_objects_freed_ever_(0), 120 num_bytes_allocated_(0), 121 native_bytes_allocated_(0), 122 gc_memory_overhead_(0), 123 verify_missing_card_marks_(false), 124 verify_system_weaks_(false), 125 verify_pre_gc_heap_(verify_pre_gc_heap), 126 verify_post_gc_heap_(verify_post_gc_heap), 127 verify_mod_union_table_(false), 128 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 129 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 130 last_trim_time_ms_(0), 131 allocation_rate_(0), 132 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 133 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 134 * verification is enabled, we limit the size of allocation stacks to speed up their 135 * searching. 136 */ 137 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 138 : (kDesiredHeapVerification > kVerifyAllFast) ? KB : MB), 139 current_allocator_(kAllocatorTypeDlMalloc), 140 current_non_moving_allocator_(kAllocatorTypeNonMoving), 141 bump_pointer_space_(nullptr), 142 temp_space_(nullptr), 143 reference_referent_offset_(0), 144 reference_queue_offset_(0), 145 reference_queueNext_offset_(0), 146 reference_pendingNext_offset_(0), 147 finalizer_reference_zombie_offset_(0), 148 min_free_(min_free), 149 max_free_(max_free), 150 target_utilization_(target_utilization), 151 total_wait_time_(0), 152 total_allocation_time_(0), 153 verify_object_mode_(kHeapVerificationNotPermitted), 154 disable_moving_gc_count_(0), 155 running_on_valgrind_(RUNNING_ON_VALGRIND), 156 use_tlab_(use_tlab) { 157 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 158 LOG(INFO) << "Heap() entering"; 159 } 160 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 161 // entrypoints. 162 if (!Runtime::Current()->IsZygote() || !kMovingCollector) { 163 ChangeCollector(post_zygote_collector_type_); 164 } else { 165 // We are the zygote, use bump pointer allocation + semi space collector. 166 ChangeCollector(kCollectorTypeSS); 167 } 168 169 live_bitmap_.reset(new accounting::HeapBitmap(this)); 170 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 171 // Requested begin for the alloc space, to follow the mapped image and oat files 172 byte* requested_alloc_space_begin = nullptr; 173 if (!image_file_name.empty()) { 174 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 175 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 176 AddSpace(image_space); 177 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 178 // isn't going to get in the middle 179 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 180 CHECK_GT(oat_file_end_addr, image_space->End()); 181 if (oat_file_end_addr > requested_alloc_space_begin) { 182 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 183 } 184 } 185 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 186 space::MallocSpace* malloc_space; 187 if (kUseRosAlloc) { 188 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 189 requested_alloc_space_begin, low_memory_mode_); 190 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 191 } else { 192 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 193 requested_alloc_space_begin); 194 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 195 } 196 VLOG(heap) << "malloc_space : " << malloc_space; 197 if (kMovingCollector) { 198 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 199 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 200 // issues. 201 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 202 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 203 bump_pointer_space_size, nullptr); 204 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 205 AddSpace(bump_pointer_space_); 206 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 207 nullptr); 208 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 209 AddSpace(temp_space_); 210 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 211 VLOG(heap) << "temp_space : " << temp_space_; 212 } 213 non_moving_space_ = malloc_space; 214 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 215 AddSpace(malloc_space); 216 217 // Allocate the large object space. 218 constexpr bool kUseFreeListSpaceForLOS = false; 219 if (kUseFreeListSpaceForLOS) { 220 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 221 } else { 222 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 223 } 224 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 225 AddSpace(large_object_space_); 226 227 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 228 CHECK(!continuous_spaces_.empty()); 229 230 // Relies on the spaces being sorted. 231 byte* heap_begin = continuous_spaces_.front()->Begin(); 232 byte* heap_end = continuous_spaces_.back()->Limit(); 233 if (Runtime::Current()->IsZygote()) { 234 std::string error_str; 235 post_zygote_non_moving_space_mem_map_.reset( 236 MemMap::MapAnonymous("post zygote non-moving space", nullptr, 64 * MB, 237 PROT_READ | PROT_WRITE, true, &error_str)); 238 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 239 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 240 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 241 } 242 size_t heap_capacity = heap_end - heap_begin; 243 244 // Allocate the card table. 245 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 246 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 247 248 // Card cache for now since it makes it easier for us to update the references to the copying 249 // spaces. 250 accounting::ModUnionTable* mod_union_table = 251 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 252 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 253 AddModUnionTable(mod_union_table); 254 255 // TODO: Count objects in the image space here. 256 num_bytes_allocated_ = 0; 257 258 // Default mark stack size in bytes. 259 static const size_t default_mark_stack_size = 64 * KB; 260 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 261 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 262 max_allocation_stack_size_)); 263 live_stack_.reset(accounting::ObjectStack::Create("live stack", 264 max_allocation_stack_size_)); 265 266 // It's still too early to take a lock because there are no threads yet, but we can create locks 267 // now. We don't create it earlier to make it clear that you can't use locks during heap 268 // initialization. 269 gc_complete_lock_ = new Mutex("GC complete lock"); 270 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 271 *gc_complete_lock_)); 272 last_gc_time_ns_ = NanoTime(); 273 last_gc_size_ = GetBytesAllocated(); 274 275 if (ignore_max_footprint_) { 276 SetIdealFootprint(std::numeric_limits<size_t>::max()); 277 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 278 } 279 CHECK_NE(max_allowed_footprint_, 0U); 280 281 // Create our garbage collectors. 282 for (size_t i = 0; i < 2; ++i) { 283 const bool concurrent = i != 0; 284 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 285 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 286 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 287 } 288 if (kMovingCollector) { 289 // TODO: Clean this up. 290 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 291 semi_space_collector_ = new collector::SemiSpace(this, generational); 292 garbage_collectors_.push_back(semi_space_collector_); 293 } 294 295 if (running_on_valgrind_) { 296 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 297 } 298 299 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 300 LOG(INFO) << "Heap() exiting"; 301 } 302} 303 304void Heap::ChangeAllocator(AllocatorType allocator) { 305 // These two allocators are only used internally and don't have any entrypoints. 306 DCHECK_NE(allocator, kAllocatorTypeLOS); 307 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 308 if (current_allocator_ != allocator) { 309 current_allocator_ = allocator; 310 SetQuickAllocEntryPointsAllocator(current_allocator_); 311 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 312 } 313} 314 315bool Heap::IsCompilingBoot() const { 316 for (const auto& space : continuous_spaces_) { 317 if (space->IsImageSpace()) { 318 return false; 319 } else if (space->IsZygoteSpace()) { 320 return false; 321 } 322 } 323 return true; 324} 325 326bool Heap::HasImageSpace() const { 327 for (const auto& space : continuous_spaces_) { 328 if (space->IsImageSpace()) { 329 return true; 330 } 331 } 332 return false; 333} 334 335void Heap::IncrementDisableMovingGC(Thread* self) { 336 // Need to do this holding the lock to prevent races where the GC is about to run / running when 337 // we attempt to disable it. 338 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 339 MutexLock mu(self, *gc_complete_lock_); 340 ++disable_moving_gc_count_; 341 if (IsCompactingGC(collector_type_running_)) { 342 WaitForGcToCompleteLocked(self); 343 } 344} 345 346void Heap::DecrementDisableMovingGC(Thread* self) { 347 MutexLock mu(self, *gc_complete_lock_); 348 CHECK_GE(disable_moving_gc_count_, 0U); 349 --disable_moving_gc_count_; 350} 351 352void Heap::UpdateProcessState(ProcessState process_state) { 353 if (process_state_ != process_state) { 354 process_state_ = process_state; 355 if (process_state_ == kProcessStateJankPerceptible) { 356 TransitionCollector(post_zygote_collector_type_); 357 } else { 358 TransitionCollector(background_collector_type_); 359 } 360 } else { 361 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 362 } 363} 364 365void Heap::CreateThreadPool() { 366 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 367 if (num_threads != 0) { 368 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 369 } 370} 371 372void Heap::VisitObjects(ObjectCallback callback, void* arg) { 373 Thread* self = Thread::Current(); 374 // GCs can move objects, so don't allow this. 375 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 376 if (bump_pointer_space_ != nullptr) { 377 // Visit objects in bump pointer space. 378 bump_pointer_space_->Walk(callback, arg); 379 } 380 // TODO: Switch to standard begin and end to use ranged a based loop. 381 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 382 it < end; ++it) { 383 mirror::Object* obj = *it; 384 if (obj != nullptr && obj->GetClass() != nullptr) { 385 // Avoid the race condition caused by the object not yet being written into the allocation 386 // stack or the class not yet being written in the object. 387 callback(obj, arg); 388 } 389 } 390 GetLiveBitmap()->Walk(callback, arg); 391 self->EndAssertNoThreadSuspension(old_cause); 392} 393 394void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 395 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 396 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 397 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 398 // TODO: Generalize this to n bitmaps? 399 if (space1 == nullptr) { 400 DCHECK(space2 != nullptr); 401 space1 = space2; 402 } 403 if (space2 == nullptr) { 404 DCHECK(space1 != nullptr); 405 space2 = space1; 406 } 407 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 408 large_object_space_->GetLiveObjects(), stack); 409} 410 411void Heap::DeleteThreadPool() { 412 thread_pool_.reset(nullptr); 413} 414 415void Heap::AddSpace(space::Space* space, bool set_as_default) { 416 DCHECK(space != nullptr); 417 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 418 if (space->IsContinuousSpace()) { 419 DCHECK(!space->IsDiscontinuousSpace()); 420 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 421 // Continuous spaces don't necessarily have bitmaps. 422 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 423 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 424 if (live_bitmap != nullptr) { 425 DCHECK(mark_bitmap != nullptr); 426 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 427 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 428 } 429 continuous_spaces_.push_back(continuous_space); 430 if (set_as_default) { 431 if (continuous_space->IsDlMallocSpace()) { 432 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 433 } else if (continuous_space->IsRosAllocSpace()) { 434 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 435 } 436 } 437 // Ensure that spaces remain sorted in increasing order of start address. 438 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 439 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 440 return a->Begin() < b->Begin(); 441 }); 442 } else { 443 DCHECK(space->IsDiscontinuousSpace()); 444 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 445 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 446 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 447 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 448 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 449 discontinuous_spaces_.push_back(discontinuous_space); 450 } 451 if (space->IsAllocSpace()) { 452 alloc_spaces_.push_back(space->AsAllocSpace()); 453 } 454} 455 456void Heap::RemoveSpace(space::Space* space) { 457 DCHECK(space != nullptr); 458 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 459 if (space->IsContinuousSpace()) { 460 DCHECK(!space->IsDiscontinuousSpace()); 461 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 462 // Continuous spaces don't necessarily have bitmaps. 463 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 464 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 465 if (live_bitmap != nullptr) { 466 DCHECK(mark_bitmap != nullptr); 467 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 468 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 469 } 470 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 471 DCHECK(it != continuous_spaces_.end()); 472 continuous_spaces_.erase(it); 473 if (continuous_space == dlmalloc_space_) { 474 dlmalloc_space_ = nullptr; 475 } else if (continuous_space == rosalloc_space_) { 476 rosalloc_space_ = nullptr; 477 } 478 if (continuous_space == main_space_) { 479 main_space_ = nullptr; 480 } 481 } else { 482 DCHECK(space->IsDiscontinuousSpace()); 483 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 484 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 485 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 486 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 487 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 488 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 489 discontinuous_space); 490 DCHECK(it != discontinuous_spaces_.end()); 491 discontinuous_spaces_.erase(it); 492 } 493 if (space->IsAllocSpace()) { 494 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 495 DCHECK(it != alloc_spaces_.end()); 496 alloc_spaces_.erase(it); 497 } 498} 499 500void Heap::RegisterGCAllocation(size_t bytes) { 501 if (this != nullptr) { 502 gc_memory_overhead_.FetchAndAdd(bytes); 503 } 504} 505 506void Heap::RegisterGCDeAllocation(size_t bytes) { 507 if (this != nullptr) { 508 gc_memory_overhead_.FetchAndSub(bytes); 509 } 510} 511 512void Heap::DumpGcPerformanceInfo(std::ostream& os) { 513 // Dump cumulative timings. 514 os << "Dumping cumulative Gc timings\n"; 515 uint64_t total_duration = 0; 516 517 // Dump cumulative loggers for each GC type. 518 uint64_t total_paused_time = 0; 519 for (const auto& collector : garbage_collectors_) { 520 CumulativeLogger& logger = collector->GetCumulativeTimings(); 521 if (logger.GetTotalNs() != 0) { 522 os << Dumpable<CumulativeLogger>(logger); 523 const uint64_t total_ns = logger.GetTotalNs(); 524 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 525 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 526 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 527 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 528 Histogram<uint64_t>::CumulativeData cumulative_data; 529 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 530 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 531 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 532 << collector->GetName() << " freed: " << freed_objects 533 << " objects with total size " << PrettySize(freed_bytes) << "\n" 534 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 535 << PrettySize(freed_bytes / seconds) << "/s\n"; 536 total_duration += total_ns; 537 total_paused_time += total_pause_ns; 538 } 539 } 540 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 541 if (total_duration != 0) { 542 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 543 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 544 os << "Mean GC size throughput: " 545 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 546 os << "Mean GC object throughput: " 547 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 548 } 549 size_t total_objects_allocated = GetObjectsAllocatedEver(); 550 os << "Total number of allocations: " << total_objects_allocated << "\n"; 551 size_t total_bytes_allocated = GetBytesAllocatedEver(); 552 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 553 if (kMeasureAllocationTime) { 554 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 555 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 556 << "\n"; 557 } 558 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 559 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 560 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 561} 562 563Heap::~Heap() { 564 VLOG(heap) << "Starting ~Heap()"; 565 STLDeleteElements(&garbage_collectors_); 566 // If we don't reset then the mark stack complains in its destructor. 567 allocation_stack_->Reset(); 568 live_stack_->Reset(); 569 STLDeleteValues(&mod_union_tables_); 570 STLDeleteElements(&continuous_spaces_); 571 STLDeleteElements(&discontinuous_spaces_); 572 delete gc_complete_lock_; 573 VLOG(heap) << "Finished ~Heap()"; 574} 575 576space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 577 bool fail_ok) const { 578 for (const auto& space : continuous_spaces_) { 579 if (space->Contains(obj)) { 580 return space; 581 } 582 } 583 if (!fail_ok) { 584 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 585 } 586 return NULL; 587} 588 589space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 590 bool fail_ok) const { 591 for (const auto& space : discontinuous_spaces_) { 592 if (space->Contains(obj)) { 593 return space; 594 } 595 } 596 if (!fail_ok) { 597 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 598 } 599 return NULL; 600} 601 602space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 603 space::Space* result = FindContinuousSpaceFromObject(obj, true); 604 if (result != NULL) { 605 return result; 606 } 607 return FindDiscontinuousSpaceFromObject(obj, true); 608} 609 610struct SoftReferenceArgs { 611 IsMarkedCallback* is_marked_callback_; 612 MarkObjectCallback* recursive_mark_callback_; 613 void* arg_; 614}; 615 616mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 617 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 618 // TODO: Not preserve all soft references. 619 return args->recursive_mark_callback_(obj, args->arg_); 620} 621 622// Process reference class instances and schedule finalizations. 623void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 624 IsMarkedCallback* is_marked_callback, 625 MarkObjectCallback* recursive_mark_object_callback, void* arg) { 626 // Unless we are in the zygote or required to clear soft references with white references, 627 // preserve some white referents. 628 if (!clear_soft && !Runtime::Current()->IsZygote()) { 629 SoftReferenceArgs soft_reference_args; 630 soft_reference_args.is_marked_callback_ = is_marked_callback; 631 soft_reference_args.recursive_mark_callback_ = recursive_mark_object_callback; 632 soft_reference_args.arg_ = arg; 633 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 634 &soft_reference_args); 635 } 636 timings.StartSplit("ProcessReferences"); 637 // Clear all remaining soft and weak references with white referents. 638 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 639 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 640 timings.EndSplit(); 641 // Preserve all white objects with finalize methods and schedule them for finalization. 642 timings.StartSplit("EnqueueFinalizerReferences"); 643 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 644 recursive_mark_object_callback, arg); 645 timings.EndSplit(); 646 timings.StartSplit("ProcessReferences"); 647 // Clear all f-reachable soft and weak references with white referents. 648 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 649 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 650 // Clear all phantom references with white referents. 651 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 652 // At this point all reference queues other than the cleared references should be empty. 653 DCHECK(soft_reference_queue_.IsEmpty()); 654 DCHECK(weak_reference_queue_.IsEmpty()); 655 DCHECK(finalizer_reference_queue_.IsEmpty()); 656 DCHECK(phantom_reference_queue_.IsEmpty()); 657 timings.EndSplit(); 658} 659 660bool Heap::IsEnqueued(mirror::Object* ref) const { 661 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 662 // will always be non-null. 663 return ref->GetFieldObject<mirror::Object>(GetReferencePendingNextOffset(), false) != nullptr; 664} 665 666bool Heap::IsEnqueuable(mirror::Object* ref) const { 667 DCHECK(ref != nullptr); 668 const mirror::Object* queue = 669 ref->GetFieldObject<mirror::Object>(GetReferenceQueueOffset(), false); 670 const mirror::Object* queue_next = 671 ref->GetFieldObject<mirror::Object>(GetReferenceQueueNextOffset(), false); 672 return queue != nullptr && queue_next == nullptr; 673} 674 675// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 676// marked, put it on the appropriate list in the heap for later processing. 677void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 678 IsMarkedCallback is_marked_callback, void* arg) { 679 DCHECK(klass != nullptr); 680 DCHECK(klass->IsReferenceClass()); 681 DCHECK(obj != nullptr); 682 mirror::Object* referent = GetReferenceReferent(obj); 683 if (referent != nullptr) { 684 mirror::Object* forward_address = is_marked_callback(referent, arg); 685 // Null means that the object is not currently marked. 686 if (forward_address == nullptr) { 687 Thread* self = Thread::Current(); 688 // TODO: Remove these locks, and use atomic stacks for storing references? 689 // We need to check that the references haven't already been enqueued since we can end up 690 // scanning the same reference multiple times due to dirty cards. 691 if (klass->IsSoftReferenceClass()) { 692 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 693 } else if (klass->IsWeakReferenceClass()) { 694 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 695 } else if (klass->IsFinalizerReferenceClass()) { 696 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 697 } else if (klass->IsPhantomReferenceClass()) { 698 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 699 } else { 700 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 701 << klass->GetAccessFlags(); 702 } 703 } else if (referent != forward_address) { 704 // Referent is already marked and we need to update it. 705 SetReferenceReferent(obj, forward_address); 706 } 707 } 708} 709 710space::ImageSpace* Heap::GetImageSpace() const { 711 for (const auto& space : continuous_spaces_) { 712 if (space->IsImageSpace()) { 713 return space->AsImageSpace(); 714 } 715 } 716 return NULL; 717} 718 719static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 720 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 721 if (used_bytes < chunk_size) { 722 size_t chunk_free_bytes = chunk_size - used_bytes; 723 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 724 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 725 } 726} 727 728void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 729 std::ostringstream oss; 730 size_t total_bytes_free = GetFreeMemory(); 731 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 732 << " free bytes"; 733 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 734 if (!large_object_allocation && total_bytes_free >= byte_count) { 735 size_t max_contiguous_allocation = 0; 736 for (const auto& space : continuous_spaces_) { 737 if (space->IsMallocSpace()) { 738 // To allow the Walk/InspectAll() to exclusively-lock the mutator 739 // lock, temporarily release the shared access to the mutator 740 // lock here by transitioning to the suspended state. 741 Locks::mutator_lock_->AssertSharedHeld(self); 742 self->TransitionFromRunnableToSuspended(kSuspended); 743 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 744 self->TransitionFromSuspendedToRunnable(); 745 Locks::mutator_lock_->AssertSharedHeld(self); 746 } 747 } 748 oss << "; failed due to fragmentation (largest possible contiguous allocation " 749 << max_contiguous_allocation << " bytes)"; 750 } 751 self->ThrowOutOfMemoryError(oss.str().c_str()); 752} 753 754void Heap::Trim() { 755 Thread* self = Thread::Current(); 756 { 757 // Need to do this before acquiring the locks since we don't want to get suspended while 758 // holding any locks. 759 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 760 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 761 // trimming. 762 MutexLock mu(self, *gc_complete_lock_); 763 // Ensure there is only one GC at a time. 764 WaitForGcToCompleteLocked(self); 765 collector_type_running_ = kCollectorTypeHeapTrim; 766 } 767 uint64_t start_ns = NanoTime(); 768 // Trim the managed spaces. 769 uint64_t total_alloc_space_allocated = 0; 770 uint64_t total_alloc_space_size = 0; 771 uint64_t managed_reclaimed = 0; 772 for (const auto& space : continuous_spaces_) { 773 if (space->IsMallocSpace()) { 774 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 775 total_alloc_space_size += alloc_space->Size(); 776 managed_reclaimed += alloc_space->Trim(); 777 } 778 } 779 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 780 bump_pointer_space_->Size(); 781 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 782 static_cast<float>(total_alloc_space_size); 783 uint64_t gc_heap_end_ns = NanoTime(); 784 // We never move things in the native heap, so we can finish the GC at this point. 785 FinishGC(self, collector::kGcTypeNone); 786 // Trim the native heap. 787 dlmalloc_trim(0); 788 size_t native_reclaimed = 0; 789 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 790 uint64_t end_ns = NanoTime(); 791 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 792 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 793 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 794 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 795 << "%."; 796} 797 798bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 799 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 800 // taking the lock. 801 if (obj == nullptr) { 802 return true; 803 } 804 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 805} 806 807bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 808 return FindContinuousSpaceFromObject(obj, true) != nullptr; 809} 810 811bool Heap::IsHeapAddress(const mirror::Object* obj) const { 812 // TODO: This might not work for large objects. 813 return FindSpaceFromObject(obj, true) != nullptr; 814} 815 816bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 817 bool search_live_stack, bool sorted) { 818 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 819 return false; 820 } 821 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 822 mirror::Class* klass = obj->GetClass(); 823 if (obj == klass) { 824 // This case happens for java.lang.Class. 825 return true; 826 } 827 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 828 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 829 return false; 830 } 831 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 832 space::DiscontinuousSpace* d_space = NULL; 833 if (c_space != nullptr) { 834 if (c_space->GetLiveBitmap()->Test(obj)) { 835 return true; 836 } 837 } else { 838 d_space = FindDiscontinuousSpaceFromObject(obj, true); 839 if (d_space != nullptr) { 840 if (d_space->GetLiveObjects()->Test(obj)) { 841 return true; 842 } 843 } 844 } 845 // This is covering the allocation/live stack swapping that is done without mutators suspended. 846 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 847 if (i > 0) { 848 NanoSleep(MsToNs(10)); 849 } 850 if (search_allocation_stack) { 851 if (sorted) { 852 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 853 return true; 854 } 855 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 856 return true; 857 } 858 } 859 860 if (search_live_stack) { 861 if (sorted) { 862 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 863 return true; 864 } 865 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 866 return true; 867 } 868 } 869 } 870 // We need to check the bitmaps again since there is a race where we mark something as live and 871 // then clear the stack containing it. 872 if (c_space != nullptr) { 873 if (c_space->GetLiveBitmap()->Test(obj)) { 874 return true; 875 } 876 } else { 877 d_space = FindDiscontinuousSpaceFromObject(obj, true); 878 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 879 return true; 880 } 881 } 882 return false; 883} 884 885void Heap::VerifyObjectImpl(mirror::Object* obj) { 886 if (Thread::Current() == NULL || 887 Runtime::Current()->GetThreadList()->GetLockOwner() == Thread::Current()->GetTid()) { 888 return; 889 } 890 VerifyObjectBody(obj); 891} 892 893bool Heap::VerifyClassClass(const mirror::Class* c) const { 894 // Note: we don't use the accessors here as they have internal sanity checks that we don't want 895 // to run 896 const byte* raw_addr = 897 reinterpret_cast<const byte*>(c) + mirror::Object::ClassOffset().Int32Value(); 898 mirror::Class* c_c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 899 raw_addr = reinterpret_cast<const byte*>(c_c) + mirror::Object::ClassOffset().Int32Value(); 900 mirror::Class* c_c_c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 901 return c_c == c_c_c; 902} 903 904void Heap::DumpSpaces(std::ostream& stream) { 905 for (const auto& space : continuous_spaces_) { 906 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 907 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 908 stream << space << " " << *space << "\n"; 909 if (live_bitmap != nullptr) { 910 stream << live_bitmap << " " << *live_bitmap << "\n"; 911 } 912 if (mark_bitmap != nullptr) { 913 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 914 } 915 } 916 for (const auto& space : discontinuous_spaces_) { 917 stream << space << " " << *space << "\n"; 918 } 919} 920 921void Heap::VerifyObjectBody(mirror::Object* obj) { 922 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 923 // Ignore early dawn of the universe verifications. 924 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 925 return; 926 } 927 const byte* raw_addr = reinterpret_cast<const byte*>(obj) + 928 mirror::Object::ClassOffset().Int32Value(); 929 mirror::Class* c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 930 if (UNLIKELY(c == NULL)) { 931 LOG(FATAL) << "Null class in object: " << obj; 932 } else if (UNLIKELY(!IsAligned<kObjectAlignment>(c))) { 933 LOG(FATAL) << "Class isn't aligned: " << c << " in object: " << obj; 934 } 935 CHECK(VerifyClassClass(c)); 936 937 if (verify_object_mode_ > kVerifyAllFast) { 938 // TODO: the bitmap tests below are racy if VerifyObjectBody is called without the 939 // heap_bitmap_lock_. 940 if (!IsLiveObjectLocked(obj)) { 941 DumpSpaces(); 942 LOG(FATAL) << "Object is dead: " << obj; 943 } 944 if (!IsLiveObjectLocked(c)) { 945 LOG(FATAL) << "Class of object is dead: " << c << " in object: " << obj; 946 } 947 } 948} 949 950void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 951 DCHECK(obj != NULL); 952 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 953} 954 955void Heap::VerifyHeap() { 956 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 957 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 958} 959 960void Heap::RecordFree(size_t freed_objects, size_t freed_bytes) { 961 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 962 num_bytes_allocated_.FetchAndSub(freed_bytes); 963 if (Runtime::Current()->HasStatsEnabled()) { 964 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 965 thread_stats->freed_objects += freed_objects; 966 thread_stats->freed_bytes += freed_bytes; 967 // TODO: Do this concurrently. 968 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 969 global_stats->freed_objects += freed_objects; 970 global_stats->freed_bytes += freed_bytes; 971 } 972} 973 974mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 975 size_t alloc_size, size_t* bytes_allocated, 976 mirror::Class** klass) { 977 mirror::Object* ptr = nullptr; 978 bool was_default_allocator = allocator == GetCurrentAllocator(); 979 DCHECK(klass != nullptr); 980 SirtRef<mirror::Class> sirt_klass(self, *klass); 981 // The allocation failed. If the GC is running, block until it completes, and then retry the 982 // allocation. 983 collector::GcType last_gc = WaitForGcToComplete(self); 984 if (last_gc != collector::kGcTypeNone) { 985 // If we were the default allocator but the allocator changed while we were suspended, 986 // abort the allocation. 987 if (was_default_allocator && allocator != GetCurrentAllocator()) { 988 *klass = sirt_klass.get(); 989 return nullptr; 990 } 991 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 992 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 993 } 994 995 // Loop through our different Gc types and try to Gc until we get enough free memory. 996 for (collector::GcType gc_type : gc_plan_) { 997 if (ptr != nullptr) { 998 break; 999 } 1000 // Attempt to run the collector, if we succeed, re-try the allocation. 1001 bool gc_ran = 1002 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1003 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1004 *klass = sirt_klass.get(); 1005 return nullptr; 1006 } 1007 if (gc_ran) { 1008 // Did we free sufficient memory for the allocation to succeed? 1009 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 1010 } 1011 } 1012 // Allocations have failed after GCs; this is an exceptional state. 1013 if (ptr == nullptr) { 1014 // Try harder, growing the heap if necessary. 1015 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1016 } 1017 if (ptr == nullptr) { 1018 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1019 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1020 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1021 // OOME. 1022 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1023 << " allocation"; 1024 // TODO: Run finalization, but this may cause more allocations to occur. 1025 // We don't need a WaitForGcToComplete here either. 1026 DCHECK(!gc_plan_.empty()); 1027 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1028 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1029 *klass = sirt_klass.get(); 1030 return nullptr; 1031 } 1032 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1033 if (ptr == nullptr) { 1034 ThrowOutOfMemoryError(self, alloc_size, false); 1035 } 1036 } 1037 *klass = sirt_klass.get(); 1038 return ptr; 1039} 1040 1041void Heap::SetTargetHeapUtilization(float target) { 1042 DCHECK_GT(target, 0.0f); // asserted in Java code 1043 DCHECK_LT(target, 1.0f); 1044 target_utilization_ = target; 1045} 1046 1047size_t Heap::GetObjectsAllocated() const { 1048 size_t total = 0; 1049 for (space::AllocSpace* space : alloc_spaces_) { 1050 total += space->GetObjectsAllocated(); 1051 } 1052 return total; 1053} 1054 1055size_t Heap::GetObjectsAllocatedEver() const { 1056 return GetObjectsFreedEver() + GetObjectsAllocated(); 1057} 1058 1059size_t Heap::GetBytesAllocatedEver() const { 1060 return GetBytesFreedEver() + GetBytesAllocated(); 1061} 1062 1063class InstanceCounter { 1064 public: 1065 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1066 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1067 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1068 } 1069 static void Callback(mirror::Object* obj, void* arg) 1070 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1071 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1072 mirror::Class* instance_class = obj->GetClass(); 1073 CHECK(instance_class != nullptr); 1074 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1075 if (instance_counter->use_is_assignable_from_) { 1076 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1077 ++instance_counter->counts_[i]; 1078 } 1079 } else if (instance_class == instance_counter->classes_[i]) { 1080 ++instance_counter->counts_[i]; 1081 } 1082 } 1083 } 1084 1085 private: 1086 const std::vector<mirror::Class*>& classes_; 1087 bool use_is_assignable_from_; 1088 uint64_t* const counts_; 1089 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1090}; 1091 1092void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1093 uint64_t* counts) { 1094 // Can't do any GC in this function since this may move classes. 1095 Thread* self = Thread::Current(); 1096 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1097 InstanceCounter counter(classes, use_is_assignable_from, counts); 1098 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1099 VisitObjects(InstanceCounter::Callback, &counter); 1100 self->EndAssertNoThreadSuspension(old_cause); 1101} 1102 1103class InstanceCollector { 1104 public: 1105 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1106 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1107 : class_(c), max_count_(max_count), instances_(instances) { 1108 } 1109 static void Callback(mirror::Object* obj, void* arg) 1110 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1111 DCHECK(arg != nullptr); 1112 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1113 mirror::Class* instance_class = obj->GetClass(); 1114 if (instance_class == instance_collector->class_) { 1115 if (instance_collector->max_count_ == 0 || 1116 instance_collector->instances_.size() < instance_collector->max_count_) { 1117 instance_collector->instances_.push_back(obj); 1118 } 1119 } 1120 } 1121 1122 private: 1123 mirror::Class* class_; 1124 uint32_t max_count_; 1125 std::vector<mirror::Object*>& instances_; 1126 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1127}; 1128 1129void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1130 std::vector<mirror::Object*>& instances) { 1131 // Can't do any GC in this function since this may move classes. 1132 Thread* self = Thread::Current(); 1133 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1134 InstanceCollector collector(c, max_count, instances); 1135 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1136 VisitObjects(&InstanceCollector::Callback, &collector); 1137 self->EndAssertNoThreadSuspension(old_cause); 1138} 1139 1140class ReferringObjectsFinder { 1141 public: 1142 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1143 std::vector<mirror::Object*>& referring_objects) 1144 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1145 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1146 } 1147 1148 static void Callback(mirror::Object* obj, void* arg) 1149 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1150 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1151 } 1152 1153 // For bitmap Visit. 1154 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1155 // annotalysis on visitors. 1156 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1157 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1158 } 1159 1160 // For MarkSweep::VisitObjectReferences. 1161 void operator()(mirror::Object* referrer, mirror::Object* object, 1162 const MemberOffset&, bool) const { 1163 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1164 referring_objects_.push_back(referrer); 1165 } 1166 } 1167 1168 private: 1169 mirror::Object* object_; 1170 uint32_t max_count_; 1171 std::vector<mirror::Object*>& referring_objects_; 1172 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1173}; 1174 1175void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1176 std::vector<mirror::Object*>& referring_objects) { 1177 // Can't do any GC in this function since this may move the object o. 1178 Thread* self = Thread::Current(); 1179 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1180 ReferringObjectsFinder finder(o, max_count, referring_objects); 1181 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1182 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1183 self->EndAssertNoThreadSuspension(old_cause); 1184} 1185 1186void Heap::CollectGarbage(bool clear_soft_references) { 1187 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1188 // last GC will not have necessarily been cleared. 1189 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1190} 1191 1192void Heap::TransitionCollector(CollectorType collector_type) { 1193 if (collector_type == collector_type_) { 1194 return; 1195 } 1196 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1197 << " -> " << static_cast<int>(collector_type); 1198 uint64_t start_time = NanoTime(); 1199 uint32_t before_size = GetTotalMemory(); 1200 uint32_t before_allocated = num_bytes_allocated_.Load(); 1201 ThreadList* tl = Runtime::Current()->GetThreadList(); 1202 Thread* self = Thread::Current(); 1203 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1204 Locks::mutator_lock_->AssertNotHeld(self); 1205 const bool copying_transition = 1206 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1207 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1208 // compacting_gc_disable_count_, this should rarely occurs). 1209 for (;;) { 1210 { 1211 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1212 MutexLock mu(self, *gc_complete_lock_); 1213 // Ensure there is only one GC at a time. 1214 WaitForGcToCompleteLocked(self); 1215 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1216 if (!copying_transition || disable_moving_gc_count_ == 0) { 1217 // TODO: Not hard code in semi-space collector? 1218 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1219 break; 1220 } 1221 } 1222 usleep(1000); 1223 } 1224 tl->SuspendAll(); 1225 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1226 switch (collector_type) { 1227 case kCollectorTypeSS: 1228 // Fall-through. 1229 case kCollectorTypeGSS: { 1230 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1231 CHECK(main_space_ != nullptr); 1232 Compact(temp_space_, main_space_); 1233 DCHECK(allocator_mem_map_.get() == nullptr); 1234 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1235 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1236 // RemoveSpace does not delete the removed space. 1237 space::Space* old_space = main_space_; 1238 RemoveSpace(old_space); 1239 delete old_space; 1240 break; 1241 } 1242 case kCollectorTypeMS: 1243 // Fall through. 1244 case kCollectorTypeCMS: { 1245 if (IsCompactingGC(collector_type_)) { 1246 // TODO: Use mem-map from temp space? 1247 MemMap* mem_map = allocator_mem_map_.release(); 1248 CHECK(mem_map != nullptr); 1249 size_t initial_size = kDefaultInitialSize; 1250 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1251 CHECK(main_space_ == nullptr); 1252 if (kUseRosAlloc) { 1253 main_space_ = 1254 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1255 initial_size, mem_map->Size(), 1256 mem_map->Size(), low_memory_mode_); 1257 } else { 1258 main_space_ = 1259 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1260 initial_size, mem_map->Size(), 1261 mem_map->Size()); 1262 } 1263 main_space_->SetFootprintLimit(main_space_->Capacity()); 1264 AddSpace(main_space_); 1265 Compact(main_space_, bump_pointer_space_); 1266 } 1267 break; 1268 } 1269 default: { 1270 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1271 break; 1272 } 1273 } 1274 ChangeCollector(collector_type); 1275 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1276 tl->ResumeAll(); 1277 // Can't call into java code with all threads suspended. 1278 EnqueueClearedReferences(); 1279 uint64_t duration = NanoTime() - start_time; 1280 GrowForUtilization(collector::kGcTypeFull, duration); 1281 FinishGC(self, collector::kGcTypeFull); 1282 int32_t after_size = GetTotalMemory(); 1283 int32_t delta_size = before_size - after_size; 1284 int32_t after_allocated = num_bytes_allocated_.Load(); 1285 int32_t delta_allocated = before_allocated - after_allocated; 1286 const std::string saved_bytes_str = 1287 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1288 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1289 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1290 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1291 << PrettySize(delta_size) << " saved"; 1292} 1293 1294void Heap::ChangeCollector(CollectorType collector_type) { 1295 // TODO: Only do this with all mutators suspended to avoid races. 1296 if (collector_type != collector_type_) { 1297 collector_type_ = collector_type; 1298 gc_plan_.clear(); 1299 switch (collector_type_) { 1300 case kCollectorTypeSS: 1301 // Fall-through. 1302 case kCollectorTypeGSS: { 1303 concurrent_gc_ = false; 1304 gc_plan_.push_back(collector::kGcTypeFull); 1305 if (use_tlab_) { 1306 ChangeAllocator(kAllocatorTypeTLAB); 1307 } else { 1308 ChangeAllocator(kAllocatorTypeBumpPointer); 1309 } 1310 break; 1311 } 1312 case kCollectorTypeMS: { 1313 concurrent_gc_ = false; 1314 gc_plan_.push_back(collector::kGcTypeSticky); 1315 gc_plan_.push_back(collector::kGcTypePartial); 1316 gc_plan_.push_back(collector::kGcTypeFull); 1317 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1318 break; 1319 } 1320 case kCollectorTypeCMS: { 1321 concurrent_gc_ = true; 1322 gc_plan_.push_back(collector::kGcTypeSticky); 1323 gc_plan_.push_back(collector::kGcTypePartial); 1324 gc_plan_.push_back(collector::kGcTypeFull); 1325 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1326 break; 1327 } 1328 default: { 1329 LOG(FATAL) << "Unimplemented"; 1330 } 1331 } 1332 if (concurrent_gc_) { 1333 concurrent_start_bytes_ = 1334 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1335 } else { 1336 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1337 } 1338 } 1339} 1340 1341// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1342class ZygoteCompactingCollector : public collector::SemiSpace { 1343 public: 1344 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector") { 1345 } 1346 1347 void BuildBins(space::ContinuousSpace* space) { 1348 bin_live_bitmap_ = space->GetLiveBitmap(); 1349 bin_mark_bitmap_ = space->GetMarkBitmap(); 1350 BinContext context; 1351 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1352 context.collector_ = this; 1353 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1354 // Note: This requires traversing the space in increasing order of object addresses. 1355 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1356 // Add the last bin which spans after the last object to the end of the space. 1357 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1358 } 1359 1360 private: 1361 struct BinContext { 1362 uintptr_t prev_; // The end of the previous object. 1363 ZygoteCompactingCollector* collector_; 1364 }; 1365 // Maps from bin sizes to locations. 1366 std::multimap<size_t, uintptr_t> bins_; 1367 // Live bitmap of the space which contains the bins. 1368 accounting::SpaceBitmap* bin_live_bitmap_; 1369 // Mark bitmap of the space which contains the bins. 1370 accounting::SpaceBitmap* bin_mark_bitmap_; 1371 1372 static void Callback(mirror::Object* obj, void* arg) 1373 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1374 DCHECK(arg != nullptr); 1375 BinContext* context = reinterpret_cast<BinContext*>(arg); 1376 ZygoteCompactingCollector* collector = context->collector_; 1377 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1378 size_t bin_size = object_addr - context->prev_; 1379 // Add the bin consisting of the end of the previous object to the start of the current object. 1380 collector->AddBin(bin_size, context->prev_); 1381 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1382 } 1383 1384 void AddBin(size_t size, uintptr_t position) { 1385 if (size != 0) { 1386 bins_.insert(std::make_pair(size, position)); 1387 } 1388 } 1389 1390 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1391 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1392 // allocator. 1393 return false; 1394 } 1395 1396 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1397 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1398 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1399 mirror::Object* forward_address; 1400 // Find the smallest bin which we can move obj in. 1401 auto it = bins_.lower_bound(object_size); 1402 if (it == bins_.end()) { 1403 // No available space in the bins, place it in the target space instead (grows the zygote 1404 // space). 1405 size_t bytes_allocated; 1406 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated); 1407 if (to_space_live_bitmap_ != nullptr) { 1408 to_space_live_bitmap_->Set(forward_address); 1409 } else { 1410 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1411 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1412 } 1413 } else { 1414 size_t size = it->first; 1415 uintptr_t pos = it->second; 1416 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1417 forward_address = reinterpret_cast<mirror::Object*>(pos); 1418 // Set the live and mark bits so that sweeping system weaks works properly. 1419 bin_live_bitmap_->Set(forward_address); 1420 bin_mark_bitmap_->Set(forward_address); 1421 DCHECK_GE(size, object_size); 1422 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1423 } 1424 // Copy the object over to its new location. 1425 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1426 return forward_address; 1427 } 1428}; 1429 1430void Heap::UnBindBitmaps() { 1431 for (const auto& space : GetContinuousSpaces()) { 1432 if (space->IsContinuousMemMapAllocSpace()) { 1433 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1434 if (alloc_space->HasBoundBitmaps()) { 1435 alloc_space->UnBindBitmaps(); 1436 } 1437 } 1438 } 1439} 1440 1441void Heap::PreZygoteFork() { 1442 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1443 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1444 Thread* self = Thread::Current(); 1445 MutexLock mu(self, zygote_creation_lock_); 1446 // Try to see if we have any Zygote spaces. 1447 if (have_zygote_space_) { 1448 return; 1449 } 1450 VLOG(heap) << "Starting PreZygoteFork"; 1451 // Trim the pages at the end of the non moving space. 1452 non_moving_space_->Trim(); 1453 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1454 // Change the collector to the post zygote one. 1455 ChangeCollector(post_zygote_collector_type_); 1456 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1457 if (semi_space_collector_ != nullptr) { 1458 // Temporarily disable rosalloc verification because the zygote 1459 // compaction will mess up the rosalloc internal metadata. 1460 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1461 ZygoteCompactingCollector zygote_collector(this); 1462 zygote_collector.BuildBins(non_moving_space_); 1463 // Create a new bump pointer space which we will compact into. 1464 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1465 non_moving_space_->Limit()); 1466 // Compact the bump pointer space to a new zygote bump pointer space. 1467 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1468 zygote_collector.SetFromSpace(bump_pointer_space_); 1469 zygote_collector.SetToSpace(&target_space); 1470 zygote_collector.Run(kGcCauseCollectorTransition, false); 1471 CHECK(temp_space_->IsEmpty()); 1472 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1473 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1474 // Update the end and write out image. 1475 non_moving_space_->SetEnd(target_space.End()); 1476 non_moving_space_->SetLimit(target_space.Limit()); 1477 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1478 } 1479 // Save the old space so that we can remove it after we complete creating the zygote space. 1480 space::MallocSpace* old_alloc_space = non_moving_space_; 1481 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1482 // the remaining available space. 1483 // Remove the old space before creating the zygote space since creating the zygote space sets 1484 // the old alloc space's bitmaps to nullptr. 1485 RemoveSpace(old_alloc_space); 1486 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1487 low_memory_mode_, 1488 &main_space_); 1489 delete old_alloc_space; 1490 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1491 AddSpace(zygote_space, false); 1492 CHECK(main_space_ != nullptr); 1493 if (main_space_->IsRosAllocSpace()) { 1494 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1495 } else if (main_space_->IsDlMallocSpace()) { 1496 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1497 } 1498 main_space_->SetFootprintLimit(main_space_->Capacity()); 1499 AddSpace(main_space_); 1500 have_zygote_space_ = true; 1501 // Create the zygote space mod union table. 1502 accounting::ModUnionTable* mod_union_table = 1503 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1504 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1505 AddModUnionTable(mod_union_table); 1506 // Reset the cumulative loggers since we now have a few additional timing phases. 1507 for (const auto& collector : garbage_collectors_) { 1508 collector->ResetCumulativeStatistics(); 1509 } 1510 // Can't use RosAlloc for non moving space due to thread local buffers. 1511 // TODO: Non limited space for non-movable objects? 1512 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1513 space::MallocSpace* new_non_moving_space = 1514 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1515 2 * MB, mem_map->Size(), mem_map->Size()); 1516 AddSpace(new_non_moving_space, false); 1517 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1518 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1519 non_moving_space_ = new_non_moving_space; 1520} 1521 1522void Heap::FlushAllocStack() { 1523 MarkAllocStackAsLive(allocation_stack_.get()); 1524 allocation_stack_->Reset(); 1525} 1526 1527void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1528 accounting::SpaceBitmap* bitmap2, 1529 accounting::ObjectSet* large_objects, 1530 accounting::ObjectStack* stack) { 1531 DCHECK(bitmap1 != nullptr); 1532 DCHECK(bitmap2 != nullptr); 1533 mirror::Object** limit = stack->End(); 1534 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1535 const mirror::Object* obj = *it; 1536 DCHECK(obj != nullptr); 1537 if (bitmap1->HasAddress(obj)) { 1538 bitmap1->Set(obj); 1539 } else if (bitmap2->HasAddress(obj)) { 1540 bitmap2->Set(obj); 1541 } else { 1542 large_objects->Set(obj); 1543 } 1544 } 1545} 1546 1547void Heap::SwapSemiSpaces() { 1548 // Swap the spaces so we allocate into the space which we just evacuated. 1549 std::swap(bump_pointer_space_, temp_space_); 1550} 1551 1552void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1553 space::ContinuousMemMapAllocSpace* source_space) { 1554 CHECK(kMovingCollector); 1555 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1556 if (target_space != source_space) { 1557 semi_space_collector_->SetFromSpace(source_space); 1558 semi_space_collector_->SetToSpace(target_space); 1559 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1560 } 1561} 1562 1563collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1564 bool clear_soft_references) { 1565 Thread* self = Thread::Current(); 1566 Runtime* runtime = Runtime::Current(); 1567 // If the heap can't run the GC, silently fail and return that no GC was run. 1568 switch (gc_type) { 1569 case collector::kGcTypePartial: { 1570 if (!have_zygote_space_) { 1571 return collector::kGcTypeNone; 1572 } 1573 break; 1574 } 1575 default: { 1576 // Other GC types don't have any special cases which makes them not runnable. The main case 1577 // here is full GC. 1578 } 1579 } 1580 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1581 Locks::mutator_lock_->AssertNotHeld(self); 1582 if (self->IsHandlingStackOverflow()) { 1583 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1584 } 1585 bool compacting_gc; 1586 { 1587 gc_complete_lock_->AssertNotHeld(self); 1588 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1589 MutexLock mu(self, *gc_complete_lock_); 1590 // Ensure there is only one GC at a time. 1591 WaitForGcToCompleteLocked(self); 1592 compacting_gc = IsCompactingGC(collector_type_); 1593 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1594 if (compacting_gc && disable_moving_gc_count_ != 0) { 1595 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1596 return collector::kGcTypeNone; 1597 } 1598 collector_type_running_ = collector_type_; 1599 } 1600 1601 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1602 ++runtime->GetStats()->gc_for_alloc_count; 1603 ++self->GetStats()->gc_for_alloc_count; 1604 } 1605 uint64_t gc_start_time_ns = NanoTime(); 1606 uint64_t gc_start_size = GetBytesAllocated(); 1607 // Approximate allocation rate in bytes / second. 1608 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1609 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1610 if (LIKELY(ms_delta != 0)) { 1611 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1612 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1613 } 1614 1615 DCHECK_LT(gc_type, collector::kGcTypeMax); 1616 DCHECK_NE(gc_type, collector::kGcTypeNone); 1617 1618 collector::GarbageCollector* collector = nullptr; 1619 // TODO: Clean this up. 1620 if (compacting_gc) { 1621 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1622 current_allocator_ == kAllocatorTypeTLAB); 1623 gc_type = semi_space_collector_->GetGcType(); 1624 CHECK(temp_space_->IsEmpty()); 1625 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1626 semi_space_collector_->SetToSpace(temp_space_); 1627 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1628 collector = semi_space_collector_; 1629 gc_type = collector::kGcTypeFull; 1630 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1631 current_allocator_ == kAllocatorTypeDlMalloc) { 1632 for (const auto& cur_collector : garbage_collectors_) { 1633 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1634 cur_collector->GetGcType() == gc_type) { 1635 collector = cur_collector; 1636 break; 1637 } 1638 } 1639 } else { 1640 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1641 } 1642 CHECK(collector != nullptr) 1643 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1644 << " and type=" << gc_type; 1645 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1646 collector->Run(gc_cause, clear_soft_references); 1647 total_objects_freed_ever_ += collector->GetFreedObjects(); 1648 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1649 // Enqueue cleared references. 1650 EnqueueClearedReferences(); 1651 // Grow the heap so that we know when to perform the next GC. 1652 GrowForUtilization(gc_type, collector->GetDurationNs()); 1653 if (CareAboutPauseTimes()) { 1654 const size_t duration = collector->GetDurationNs(); 1655 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1656 // GC for alloc pauses the allocating thread, so consider it as a pause. 1657 bool was_slow = duration > long_gc_log_threshold_ || 1658 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1659 if (!was_slow) { 1660 for (uint64_t pause : pauses) { 1661 was_slow = was_slow || pause > long_pause_log_threshold_; 1662 } 1663 } 1664 if (was_slow) { 1665 const size_t percent_free = GetPercentFree(); 1666 const size_t current_heap_size = GetBytesAllocated(); 1667 const size_t total_memory = GetTotalMemory(); 1668 std::ostringstream pause_string; 1669 for (size_t i = 0; i < pauses.size(); ++i) { 1670 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1671 << ((i != pauses.size() - 1) ? ", " : ""); 1672 } 1673 LOG(INFO) << gc_cause << " " << collector->GetName() 1674 << " GC freed " << collector->GetFreedObjects() << "(" 1675 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1676 << collector->GetFreedLargeObjects() << "(" 1677 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1678 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1679 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1680 << " total " << PrettyDuration((duration / 1000) * 1000); 1681 if (VLOG_IS_ON(heap)) { 1682 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1683 } 1684 } 1685 } 1686 FinishGC(self, gc_type); 1687 ATRACE_END(); 1688 1689 // Inform DDMS that a GC completed. 1690 Dbg::GcDidFinish(); 1691 return gc_type; 1692} 1693 1694void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1695 MutexLock mu(self, *gc_complete_lock_); 1696 collector_type_running_ = kCollectorTypeNone; 1697 if (gc_type != collector::kGcTypeNone) { 1698 last_gc_type_ = gc_type; 1699 } 1700 // Wake anyone who may have been waiting for the GC to complete. 1701 gc_complete_cond_->Broadcast(self); 1702} 1703 1704static mirror::Object* RootMatchesObjectVisitor(mirror::Object* root, void* arg, 1705 uint32_t /*thread_id*/, RootType /*root_type*/) { 1706 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1707 if (root == obj) { 1708 LOG(INFO) << "Object " << obj << " is a root"; 1709 } 1710 return root; 1711} 1712 1713class ScanVisitor { 1714 public: 1715 void operator()(const mirror::Object* obj) const { 1716 LOG(ERROR) << "Would have rescanned object " << obj; 1717 } 1718}; 1719 1720// Verify a reference from an object. 1721class VerifyReferenceVisitor { 1722 public: 1723 explicit VerifyReferenceVisitor(Heap* heap) 1724 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1725 : heap_(heap), failed_(false) {} 1726 1727 bool Failed() const { 1728 return failed_; 1729 } 1730 1731 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1732 // analysis on visitors. 1733 void operator()(mirror::Object* obj, mirror::Object* ref, 1734 const MemberOffset& offset, bool /* is_static */) const 1735 NO_THREAD_SAFETY_ANALYSIS { 1736 if (ref == nullptr || IsLive(ref)) { 1737 // Verify that the reference is live. 1738 return; 1739 } 1740 if (!failed_) { 1741 // Print message on only on first failure to prevent spam. 1742 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1743 failed_ = true; 1744 } 1745 if (obj != nullptr) { 1746 accounting::CardTable* card_table = heap_->GetCardTable(); 1747 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1748 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1749 byte* card_addr = card_table->CardFromAddr(obj); 1750 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1751 << offset << "\n card value = " << static_cast<int>(*card_addr); 1752 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1753 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1754 } else { 1755 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1756 } 1757 1758 // Attmept to find the class inside of the recently freed objects. 1759 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1760 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1761 space::MallocSpace* space = ref_space->AsMallocSpace(); 1762 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1763 if (ref_class != nullptr) { 1764 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1765 << PrettyClass(ref_class); 1766 } else { 1767 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1768 } 1769 } 1770 1771 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1772 ref->GetClass()->IsClass()) { 1773 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1774 } else { 1775 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1776 << ") is not a valid heap address"; 1777 } 1778 1779 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1780 void* cover_begin = card_table->AddrFromCard(card_addr); 1781 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1782 accounting::CardTable::kCardSize); 1783 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1784 << "-" << cover_end; 1785 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1786 1787 if (bitmap == nullptr) { 1788 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1789 if (!heap_->VerifyClassClass(obj->GetClass())) { 1790 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1791 } 1792 } else { 1793 // Print out how the object is live. 1794 if (bitmap->Test(obj)) { 1795 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1796 } 1797 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1798 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1799 } 1800 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1801 LOG(ERROR) << "Object " << obj << " found in live stack"; 1802 } 1803 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1804 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1805 } 1806 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1807 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1808 } 1809 // Attempt to see if the card table missed the reference. 1810 ScanVisitor scan_visitor; 1811 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1812 card_table->Scan(bitmap, byte_cover_begin, 1813 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1814 } 1815 1816 // Search to see if any of the roots reference our object. 1817 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1818 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1819 1820 // Search to see if any of the roots reference our reference. 1821 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1822 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1823 } else { 1824 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 1825 } 1826 } 1827 1828 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1829 return heap_->IsLiveObjectLocked(obj, true, false, true); 1830 } 1831 1832 static mirror::Object* VerifyRoots(mirror::Object* root, void* arg, uint32_t /*thread_id*/, 1833 RootType /*root_type*/) { 1834 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1835 (*visitor)(nullptr, root, MemberOffset(0), true); 1836 return root; 1837 } 1838 1839 private: 1840 Heap* const heap_; 1841 mutable bool failed_; 1842}; 1843 1844// Verify all references within an object, for use with HeapBitmap::Visit. 1845class VerifyObjectVisitor { 1846 public: 1847 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1848 1849 void operator()(mirror::Object* obj) const 1850 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1851 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1852 // be live or else how did we find it in the live bitmap? 1853 VerifyReferenceVisitor visitor(heap_); 1854 // The class doesn't count as a reference but we should verify it anyways. 1855 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1856 if (obj->GetClass()->IsReferenceClass()) { 1857 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1858 } 1859 failed_ = failed_ || visitor.Failed(); 1860 } 1861 1862 static void VisitCallback(mirror::Object* obj, void* arg) 1863 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1864 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1865 visitor->operator()(obj); 1866 } 1867 1868 bool Failed() const { 1869 return failed_; 1870 } 1871 1872 private: 1873 Heap* const heap_; 1874 mutable bool failed_; 1875}; 1876 1877// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1878bool Heap::VerifyHeapReferences() { 1879 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1880 // Lets sort our allocation stacks so that we can efficiently binary search them. 1881 allocation_stack_->Sort(); 1882 live_stack_->Sort(); 1883 VerifyObjectVisitor visitor(this); 1884 // Verify objects in the allocation stack since these will be objects which were: 1885 // 1. Allocated prior to the GC (pre GC verification). 1886 // 2. Allocated during the GC (pre sweep GC verification). 1887 // We don't want to verify the objects in the live stack since they themselves may be 1888 // pointing to dead objects if they are not reachable. 1889 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1890 // Verify the roots: 1891 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1892 if (visitor.Failed()) { 1893 // Dump mod-union tables. 1894 for (const auto& table_pair : mod_union_tables_) { 1895 accounting::ModUnionTable* mod_union_table = table_pair.second; 1896 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1897 } 1898 DumpSpaces(); 1899 return false; 1900 } 1901 return true; 1902} 1903 1904class VerifyReferenceCardVisitor { 1905 public: 1906 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1907 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1908 Locks::heap_bitmap_lock_) 1909 : heap_(heap), failed_(failed) { 1910 } 1911 1912 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1913 // annotalysis on visitors. 1914 void operator()(mirror::Object* obj, mirror::Object* ref, const MemberOffset& offset, 1915 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1916 // Filter out class references since changing an object's class does not mark the card as dirty. 1917 // Also handles large objects, since the only reference they hold is a class reference. 1918 if (ref != NULL && !ref->IsClass()) { 1919 accounting::CardTable* card_table = heap_->GetCardTable(); 1920 // If the object is not dirty and it is referencing something in the live stack other than 1921 // class, then it must be on a dirty card. 1922 if (!card_table->AddrIsInCardTable(obj)) { 1923 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1924 *failed_ = true; 1925 } else if (!card_table->IsDirty(obj)) { 1926 // TODO: Check mod-union tables. 1927 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1928 // kCardDirty - 1 if it didnt get touched since we aged it. 1929 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1930 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1931 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1932 LOG(ERROR) << "Object " << obj << " found in live stack"; 1933 } 1934 if (heap_->GetLiveBitmap()->Test(obj)) { 1935 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1936 } 1937 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1938 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1939 1940 // Print which field of the object is dead. 1941 if (!obj->IsObjectArray()) { 1942 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1943 CHECK(klass != NULL); 1944 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1945 : klass->GetIFields(); 1946 CHECK(fields != NULL); 1947 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1948 mirror::ArtField* cur = fields->Get(i); 1949 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1950 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1951 << PrettyField(cur); 1952 break; 1953 } 1954 } 1955 } else { 1956 mirror::ObjectArray<mirror::Object>* object_array = 1957 obj->AsObjectArray<mirror::Object>(); 1958 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1959 if (object_array->Get(i) == ref) { 1960 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1961 } 1962 } 1963 } 1964 1965 *failed_ = true; 1966 } 1967 } 1968 } 1969 } 1970 1971 private: 1972 Heap* const heap_; 1973 bool* const failed_; 1974}; 1975 1976class VerifyLiveStackReferences { 1977 public: 1978 explicit VerifyLiveStackReferences(Heap* heap) 1979 : heap_(heap), 1980 failed_(false) {} 1981 1982 void operator()(mirror::Object* obj) const 1983 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1984 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1985 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1986 } 1987 1988 bool Failed() const { 1989 return failed_; 1990 } 1991 1992 private: 1993 Heap* const heap_; 1994 bool failed_; 1995}; 1996 1997bool Heap::VerifyMissingCardMarks() { 1998 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1999 2000 // We need to sort the live stack since we binary search it. 2001 live_stack_->Sort(); 2002 VerifyLiveStackReferences visitor(this); 2003 GetLiveBitmap()->Visit(visitor); 2004 2005 // We can verify objects in the live stack since none of these should reference dead objects. 2006 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2007 visitor(*it); 2008 } 2009 2010 if (visitor.Failed()) { 2011 DumpSpaces(); 2012 return false; 2013 } 2014 return true; 2015} 2016 2017void Heap::SwapStacks() { 2018 allocation_stack_.swap(live_stack_); 2019} 2020 2021accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2022 auto it = mod_union_tables_.find(space); 2023 if (it == mod_union_tables_.end()) { 2024 return nullptr; 2025 } 2026 return it->second; 2027} 2028 2029void Heap::ProcessCards(TimingLogger& timings) { 2030 // Clear cards and keep track of cards cleared in the mod-union table. 2031 for (const auto& space : continuous_spaces_) { 2032 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2033 if (table != nullptr) { 2034 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2035 "ImageModUnionClearCards"; 2036 TimingLogger::ScopedSplit split(name, &timings); 2037 table->ClearCards(); 2038 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2039 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2040 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2041 // were dirty before the GC started. 2042 // TODO: Don't need to use atomic. 2043 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2044 // roots and then we scan / update mod union tables after. We will always scan either card. 2045 // If we end up with the non aged card, we scan it it in the pause. 2046 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2047 } 2048 } 2049} 2050 2051static mirror::Object* IdentityRootCallback(mirror::Object* obj, void*, uint32_t, RootType) { 2052 return obj; 2053} 2054 2055void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2056 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2057 Thread* self = Thread::Current(); 2058 2059 if (verify_pre_gc_heap_) { 2060 thread_list->SuspendAll(); 2061 { 2062 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2063 if (!VerifyHeapReferences()) { 2064 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2065 } 2066 } 2067 thread_list->ResumeAll(); 2068 } 2069 2070 // Check that all objects which reference things in the live stack are on dirty cards. 2071 if (verify_missing_card_marks_) { 2072 thread_list->SuspendAll(); 2073 { 2074 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2075 SwapStacks(); 2076 // Sort the live stack so that we can quickly binary search it later. 2077 if (!VerifyMissingCardMarks()) { 2078 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2079 } 2080 SwapStacks(); 2081 } 2082 thread_list->ResumeAll(); 2083 } 2084 2085 if (verify_mod_union_table_) { 2086 thread_list->SuspendAll(); 2087 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2088 for (const auto& table_pair : mod_union_tables_) { 2089 accounting::ModUnionTable* mod_union_table = table_pair.second; 2090 mod_union_table->UpdateAndMarkReferences(IdentityRootCallback, nullptr); 2091 mod_union_table->Verify(); 2092 } 2093 thread_list->ResumeAll(); 2094 } 2095} 2096 2097void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2098 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2099 // reachable objects. 2100 if (verify_post_gc_heap_) { 2101 Thread* self = Thread::Current(); 2102 CHECK_NE(self->GetState(), kRunnable); 2103 { 2104 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2105 // Swapping bound bitmaps does nothing. 2106 gc->SwapBitmaps(); 2107 if (!VerifyHeapReferences()) { 2108 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2109 } 2110 gc->SwapBitmaps(); 2111 } 2112 } 2113} 2114 2115void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2116 if (verify_system_weaks_) { 2117 Thread* self = Thread::Current(); 2118 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2119 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2120 mark_sweep->VerifySystemWeaks(); 2121 } 2122} 2123 2124void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2125 if (verify_pre_gc_rosalloc_) { 2126 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2127 for (const auto& space : continuous_spaces_) { 2128 if (space->IsRosAllocSpace()) { 2129 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2130 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2131 rosalloc_space->Verify(); 2132 } 2133 } 2134 } 2135} 2136 2137void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2138 if (verify_post_gc_rosalloc_) { 2139 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2140 for (const auto& space : continuous_spaces_) { 2141 if (space->IsRosAllocSpace()) { 2142 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2143 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2144 rosalloc_space->Verify(); 2145 } 2146 } 2147 } 2148} 2149 2150collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2151 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2152 MutexLock mu(self, *gc_complete_lock_); 2153 return WaitForGcToCompleteLocked(self); 2154} 2155 2156collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2157 collector::GcType last_gc_type = collector::kGcTypeNone; 2158 uint64_t wait_start = NanoTime(); 2159 while (collector_type_running_ != kCollectorTypeNone) { 2160 ATRACE_BEGIN("GC: Wait For Completion"); 2161 // We must wait, change thread state then sleep on gc_complete_cond_; 2162 gc_complete_cond_->Wait(self); 2163 last_gc_type = last_gc_type_; 2164 ATRACE_END(); 2165 } 2166 uint64_t wait_time = NanoTime() - wait_start; 2167 total_wait_time_ += wait_time; 2168 if (wait_time > long_pause_log_threshold_) { 2169 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2170 } 2171 return last_gc_type; 2172} 2173 2174void Heap::DumpForSigQuit(std::ostream& os) { 2175 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2176 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2177 DumpGcPerformanceInfo(os); 2178} 2179 2180size_t Heap::GetPercentFree() { 2181 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2182} 2183 2184void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2185 if (max_allowed_footprint > GetMaxMemory()) { 2186 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2187 << PrettySize(GetMaxMemory()); 2188 max_allowed_footprint = GetMaxMemory(); 2189 } 2190 max_allowed_footprint_ = max_allowed_footprint; 2191} 2192 2193bool Heap::IsMovableObject(const mirror::Object* obj) const { 2194 if (kMovingCollector) { 2195 DCHECK(!IsInTempSpace(obj)); 2196 if (bump_pointer_space_->HasAddress(obj)) { 2197 return true; 2198 } 2199 // TODO: Refactor this logic into the space itself? 2200 // Objects in the main space are only copied during background -> foreground transitions or 2201 // visa versa. 2202 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2203 (IsCompactingGC(background_collector_type_) || 2204 IsCompactingGC(post_zygote_collector_type_))) { 2205 return true; 2206 } 2207 } 2208 return false; 2209} 2210 2211bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2212 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2213 return true; 2214 } 2215 return false; 2216} 2217 2218void Heap::UpdateMaxNativeFootprint() { 2219 size_t native_size = native_bytes_allocated_; 2220 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2221 size_t target_size = native_size / GetTargetHeapUtilization(); 2222 if (target_size > native_size + max_free_) { 2223 target_size = native_size + max_free_; 2224 } else if (target_size < native_size + min_free_) { 2225 target_size = native_size + min_free_; 2226 } 2227 native_footprint_gc_watermark_ = target_size; 2228 native_footprint_limit_ = 2 * target_size - native_size; 2229} 2230 2231void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2232 // We know what our utilization is at this moment. 2233 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2234 const size_t bytes_allocated = GetBytesAllocated(); 2235 last_gc_size_ = bytes_allocated; 2236 last_gc_time_ns_ = NanoTime(); 2237 size_t target_size; 2238 if (gc_type != collector::kGcTypeSticky) { 2239 // Grow the heap for non sticky GC. 2240 target_size = bytes_allocated / GetTargetHeapUtilization(); 2241 if (target_size > bytes_allocated + max_free_) { 2242 target_size = bytes_allocated + max_free_; 2243 } else if (target_size < bytes_allocated + min_free_) { 2244 target_size = bytes_allocated + min_free_; 2245 } 2246 native_need_to_run_finalization_ = true; 2247 next_gc_type_ = collector::kGcTypeSticky; 2248 } else { 2249 // Based on how close the current heap size is to the target size, decide 2250 // whether or not to do a partial or sticky GC next. 2251 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2252 next_gc_type_ = collector::kGcTypeSticky; 2253 } else { 2254 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2255 } 2256 // If we have freed enough memory, shrink the heap back down. 2257 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2258 target_size = bytes_allocated + max_free_; 2259 } else { 2260 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2261 } 2262 } 2263 if (!ignore_max_footprint_) { 2264 SetIdealFootprint(target_size); 2265 if (concurrent_gc_) { 2266 // Calculate when to perform the next ConcurrentGC. 2267 // Calculate the estimated GC duration. 2268 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2269 // Estimate how many remaining bytes we will have when we need to start the next GC. 2270 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2271 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2272 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2273 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2274 // A never going to happen situation that from the estimated allocation rate we will exceed 2275 // the applications entire footprint with the given estimated allocation rate. Schedule 2276 // another GC nearly straight away. 2277 remaining_bytes = kMinConcurrentRemainingBytes; 2278 } 2279 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2280 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2281 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2282 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2283 // right away. 2284 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2285 } 2286 } 2287} 2288 2289void Heap::ClearGrowthLimit() { 2290 growth_limit_ = capacity_; 2291 non_moving_space_->ClearGrowthLimit(); 2292} 2293 2294void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2295 MemberOffset reference_queue_offset, 2296 MemberOffset reference_queueNext_offset, 2297 MemberOffset reference_pendingNext_offset, 2298 MemberOffset finalizer_reference_zombie_offset) { 2299 reference_referent_offset_ = reference_referent_offset; 2300 reference_queue_offset_ = reference_queue_offset; 2301 reference_queueNext_offset_ = reference_queueNext_offset; 2302 reference_pendingNext_offset_ = reference_pendingNext_offset; 2303 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2304 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2305 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2306 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2307 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2308 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2309} 2310 2311void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2312 DCHECK(reference != NULL); 2313 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2314 reference->SetFieldObject(reference_referent_offset_, referent, true); 2315} 2316 2317mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2318 DCHECK(reference != NULL); 2319 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2320 return reference->GetFieldObject<mirror::Object>(reference_referent_offset_, true); 2321} 2322 2323void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2324 ScopedObjectAccess soa(self); 2325 JValue result; 2326 ArgArray arg_array("VL", 2); 2327 arg_array.Append(object); 2328 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2329 arg_array.GetArray(), arg_array.GetNumBytes(), &result, "VL"); 2330} 2331 2332void Heap::EnqueueClearedReferences() { 2333 Thread* self = Thread::Current(); 2334 Locks::mutator_lock_->AssertNotHeld(self); 2335 if (!cleared_references_.IsEmpty()) { 2336 // When a runtime isn't started there are no reference queues to care about so ignore. 2337 if (LIKELY(Runtime::Current()->IsStarted())) { 2338 ScopedObjectAccess soa(self); 2339 JValue result; 2340 ArgArray arg_array("VL", 2); 2341 arg_array.Append(cleared_references_.GetList()); 2342 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2343 arg_array.GetArray(), arg_array.GetNumBytes(), &result, "VL"); 2344 } 2345 cleared_references_.Clear(); 2346 } 2347} 2348 2349void Heap::RequestConcurrentGC(Thread* self) { 2350 // Make sure that we can do a concurrent GC. 2351 Runtime* runtime = Runtime::Current(); 2352 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2353 self->IsHandlingStackOverflow()) { 2354 return; 2355 } 2356 // We already have a request pending, no reason to start more until we update 2357 // concurrent_start_bytes_. 2358 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2359 JNIEnv* env = self->GetJniEnv(); 2360 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2361 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2362 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2363 WellKnownClasses::java_lang_Daemons_requestGC); 2364 CHECK(!env->ExceptionCheck()); 2365} 2366 2367void Heap::ConcurrentGC(Thread* self) { 2368 if (Runtime::Current()->IsShuttingDown(self)) { 2369 return; 2370 } 2371 // Wait for any GCs currently running to finish. 2372 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2373 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2374 // instead. E.g. can't do partial, so do full instead. 2375 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2376 collector::kGcTypeNone) { 2377 for (collector::GcType gc_type : gc_plan_) { 2378 // Attempt to run the collector, if we succeed, we are done. 2379 if (gc_type > next_gc_type_ && 2380 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2381 break; 2382 } 2383 } 2384 } 2385 } 2386} 2387 2388void Heap::RequestHeapTrim() { 2389 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2390 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2391 // a space it will hold its lock and can become a cause of jank. 2392 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2393 // forking. 2394 2395 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2396 // because that only marks object heads, so a large array looks like lots of empty space. We 2397 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2398 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2399 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2400 // not how much use we're making of those pages. 2401 uint64_t ms_time = MilliTime(); 2402 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2403 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2404 return; 2405 } 2406 2407 Thread* self = Thread::Current(); 2408 Runtime* runtime = Runtime::Current(); 2409 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2410 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2411 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2412 // as we don't hold the lock while requesting the trim). 2413 return; 2414 } 2415 2416 last_trim_time_ms_ = ms_time; 2417 2418 // Trim only if we do not currently care about pause times. 2419 if (!CareAboutPauseTimes()) { 2420 JNIEnv* env = self->GetJniEnv(); 2421 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2422 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2423 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2424 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2425 CHECK(!env->ExceptionCheck()); 2426 } 2427} 2428 2429void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2430 if (rosalloc_space_ != nullptr) { 2431 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2432 } 2433 if (bump_pointer_space_ != nullptr) { 2434 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2435 } 2436} 2437 2438void Heap::RevokeAllThreadLocalBuffers() { 2439 if (rosalloc_space_ != nullptr) { 2440 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2441 } 2442 if (bump_pointer_space_ != nullptr) { 2443 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2444 } 2445} 2446 2447bool Heap::IsGCRequestPending() const { 2448 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2449} 2450 2451void Heap::RunFinalization(JNIEnv* env) { 2452 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2453 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2454 CHECK(WellKnownClasses::java_lang_System != nullptr); 2455 WellKnownClasses::java_lang_System_runFinalization = 2456 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2457 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2458 } 2459 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2460 WellKnownClasses::java_lang_System_runFinalization); 2461} 2462 2463void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2464 Thread* self = ThreadForEnv(env); 2465 if (native_need_to_run_finalization_) { 2466 RunFinalization(env); 2467 UpdateMaxNativeFootprint(); 2468 native_need_to_run_finalization_ = false; 2469 } 2470 // Total number of native bytes allocated. 2471 native_bytes_allocated_.FetchAndAdd(bytes); 2472 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2473 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2474 collector::kGcTypeFull; 2475 2476 // The second watermark is higher than the gc watermark. If you hit this it means you are 2477 // allocating native objects faster than the GC can keep up with. 2478 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2479 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2480 // Just finished a GC, attempt to run finalizers. 2481 RunFinalization(env); 2482 CHECK(!env->ExceptionCheck()); 2483 } 2484 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2485 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2486 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2487 RunFinalization(env); 2488 native_need_to_run_finalization_ = false; 2489 CHECK(!env->ExceptionCheck()); 2490 } 2491 // We have just run finalizers, update the native watermark since it is very likely that 2492 // finalizers released native managed allocations. 2493 UpdateMaxNativeFootprint(); 2494 } else if (!IsGCRequestPending()) { 2495 if (concurrent_gc_) { 2496 RequestConcurrentGC(self); 2497 } else { 2498 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2499 } 2500 } 2501 } 2502} 2503 2504void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2505 int expected_size, new_size; 2506 do { 2507 expected_size = native_bytes_allocated_.Load(); 2508 new_size = expected_size - bytes; 2509 if (UNLIKELY(new_size < 0)) { 2510 ScopedObjectAccess soa(env); 2511 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2512 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2513 "registered as allocated", bytes, expected_size).c_str()); 2514 break; 2515 } 2516 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2517} 2518 2519size_t Heap::GetTotalMemory() const { 2520 size_t ret = 0; 2521 for (const auto& space : continuous_spaces_) { 2522 // Currently don't include the image space. 2523 if (!space->IsImageSpace()) { 2524 ret += space->Size(); 2525 } 2526 } 2527 for (const auto& space : discontinuous_spaces_) { 2528 if (space->IsLargeObjectSpace()) { 2529 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2530 } 2531 } 2532 return ret; 2533} 2534 2535void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2536 DCHECK(mod_union_table != nullptr); 2537 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2538} 2539 2540} // namespace gc 2541} // namespace art 2542