heap.cc revision a1602f28c0e3127ad511712d4b08db89737ae901
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <vector> 24#include <valgrind.h> 25 26#include "base/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/mark_sweep-inl.h" 38#include "gc/collector/partial_mark_sweep.h" 39#include "gc/collector/semi_space.h" 40#include "gc/collector/sticky_mark_sweep.h" 41#include "gc/space/bump_pointer_space.h" 42#include "gc/space/dlmalloc_space-inl.h" 43#include "gc/space/image_space.h" 44#include "gc/space/large_object_space.h" 45#include "gc/space/rosalloc_space-inl.h" 46#include "gc/space/space-inl.h" 47#include "gc/space/zygote_space.h" 48#include "heap-inl.h" 49#include "image.h" 50#include "invoke_arg_array_builder.h" 51#include "mirror/art_field-inl.h" 52#include "mirror/class-inl.h" 53#include "mirror/object.h" 54#include "mirror/object-inl.h" 55#include "mirror/object_array-inl.h" 56#include "object_utils.h" 57#include "os.h" 58#include "runtime.h" 59#include "ScopedLocalRef.h" 60#include "scoped_thread_state_change.h" 61#include "sirt_ref.h" 62#include "thread_list.h" 63#include "UniquePtr.h" 64#include "well_known_classes.h" 65 66namespace art { 67 68extern void SetQuickAllocEntryPointsAllocator(gc::AllocatorType allocator); 69 70namespace gc { 71 72static constexpr bool kGCALotMode = false; 73static constexpr size_t kGcAlotInterval = KB; 74// Minimum amount of remaining bytes before a concurrent GC is triggered. 75static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 76static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 77 78Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 79 double target_utilization, size_t capacity, const std::string& image_file_name, 80 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 81 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 82 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 83 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 84 bool verify_post_gc_heap) 85 : non_moving_space_(nullptr), 86 rosalloc_space_(nullptr), 87 dlmalloc_space_(nullptr), 88 main_space_(nullptr), 89 concurrent_gc_(false), 90 collector_type_(kCollectorTypeNone), 91 post_zygote_collector_type_(post_zygote_collector_type), 92 background_collector_type_(background_collector_type), 93 parallel_gc_threads_(parallel_gc_threads), 94 conc_gc_threads_(conc_gc_threads), 95 low_memory_mode_(low_memory_mode), 96 long_pause_log_threshold_(long_pause_log_threshold), 97 long_gc_log_threshold_(long_gc_log_threshold), 98 ignore_max_footprint_(ignore_max_footprint), 99 have_zygote_space_(false), 100 soft_reference_queue_(this), 101 weak_reference_queue_(this), 102 finalizer_reference_queue_(this), 103 phantom_reference_queue_(this), 104 cleared_references_(this), 105 is_gc_running_(false), 106 last_gc_type_(collector::kGcTypeNone), 107 next_gc_type_(collector::kGcTypePartial), 108 capacity_(capacity), 109 growth_limit_(growth_limit), 110 max_allowed_footprint_(initial_size), 111 native_footprint_gc_watermark_(initial_size), 112 native_footprint_limit_(2 * initial_size), 113 native_need_to_run_finalization_(false), 114 // Initially assume we perceive jank in case the process state is never updated. 115 process_state_(kProcessStateJankPerceptible), 116 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 117 total_bytes_freed_ever_(0), 118 total_objects_freed_ever_(0), 119 num_bytes_allocated_(0), 120 native_bytes_allocated_(0), 121 gc_memory_overhead_(0), 122 verify_missing_card_marks_(false), 123 verify_system_weaks_(false), 124 verify_pre_gc_heap_(verify_pre_gc_heap), 125 verify_post_gc_heap_(verify_post_gc_heap), 126 verify_mod_union_table_(false), 127 last_trim_time_ms_(0), 128 allocation_rate_(0), 129 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 130 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 131 * verification is enabled, we limit the size of allocation stacks to speed up their 132 * searching. 133 */ 134 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 135 : (kDesiredHeapVerification > kVerifyAllFast) ? KB : MB), 136 current_allocator_(kAllocatorTypeDlMalloc), 137 current_non_moving_allocator_(kAllocatorTypeNonMoving), 138 bump_pointer_space_(nullptr), 139 temp_space_(nullptr), 140 reference_referent_offset_(0), 141 reference_queue_offset_(0), 142 reference_queueNext_offset_(0), 143 reference_pendingNext_offset_(0), 144 finalizer_reference_zombie_offset_(0), 145 min_free_(min_free), 146 max_free_(max_free), 147 target_utilization_(target_utilization), 148 total_wait_time_(0), 149 total_allocation_time_(0), 150 verify_object_mode_(kHeapVerificationNotPermitted), 151 disable_moving_gc_count_(0), 152 running_on_valgrind_(RUNNING_ON_VALGRIND), 153 use_tlab_(use_tlab) { 154 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 155 LOG(INFO) << "Heap() entering"; 156 } 157 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 158 // entrypoints. 159 if (!Runtime::Current()->IsZygote() || !kMovingCollector) { 160 ChangeCollector(post_zygote_collector_type_); 161 } else { 162 // We are the zygote, use bump pointer allocation + semi space collector. 163 ChangeCollector(kCollectorTypeSS); 164 } 165 166 live_bitmap_.reset(new accounting::HeapBitmap(this)); 167 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 168 // Requested begin for the alloc space, to follow the mapped image and oat files 169 byte* requested_alloc_space_begin = nullptr; 170 if (!image_file_name.empty()) { 171 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 172 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 173 AddSpace(image_space); 174 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 175 // isn't going to get in the middle 176 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 177 CHECK_GT(oat_file_end_addr, image_space->End()); 178 if (oat_file_end_addr > requested_alloc_space_begin) { 179 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 180 } 181 } 182 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 183 space::MallocSpace* malloc_space; 184 if (kUseRosAlloc) { 185 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 186 requested_alloc_space_begin, low_memory_mode_); 187 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 188 } else { 189 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 190 requested_alloc_space_begin); 191 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 192 } 193 VLOG(heap) << "malloc_space : " << malloc_space; 194 if (kMovingCollector) { 195 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 196 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 197 // issues. 198 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 199 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 200 bump_pointer_space_size, nullptr); 201 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 202 AddSpace(bump_pointer_space_); 203 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 204 nullptr); 205 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 206 AddSpace(temp_space_); 207 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 208 VLOG(heap) << "temp_space : " << temp_space_; 209 } 210 non_moving_space_ = malloc_space; 211 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 212 AddSpace(malloc_space); 213 214 // Allocate the large object space. 215 constexpr bool kUseFreeListSpaceForLOS = false; 216 if (kUseFreeListSpaceForLOS) { 217 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 218 } else { 219 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 220 } 221 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 222 AddSpace(large_object_space_); 223 224 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 225 CHECK(!continuous_spaces_.empty()); 226 227 // Relies on the spaces being sorted. 228 byte* heap_begin = continuous_spaces_.front()->Begin(); 229 byte* heap_end = continuous_spaces_.back()->Limit(); 230 if (Runtime::Current()->IsZygote()) { 231 std::string error_str; 232 post_zygote_non_moving_space_mem_map_.reset( 233 MemMap::MapAnonymous("post zygote non-moving space", nullptr, 64 * MB, 234 PROT_READ | PROT_WRITE, &error_str)); 235 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 236 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 237 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 238 } 239 size_t heap_capacity = heap_end - heap_begin; 240 241 // Allocate the card table. 242 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 243 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 244 245 // Card cache for now since it makes it easier for us to update the references to the copying 246 // spaces. 247 accounting::ModUnionTable* mod_union_table = 248 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 249 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 250 AddModUnionTable(mod_union_table); 251 252 // TODO: Count objects in the image space here. 253 num_bytes_allocated_ = 0; 254 255 // Default mark stack size in bytes. 256 static const size_t default_mark_stack_size = 64 * KB; 257 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 258 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 259 max_allocation_stack_size_)); 260 live_stack_.reset(accounting::ObjectStack::Create("live stack", 261 max_allocation_stack_size_)); 262 263 // It's still too early to take a lock because there are no threads yet, but we can create locks 264 // now. We don't create it earlier to make it clear that you can't use locks during heap 265 // initialization. 266 gc_complete_lock_ = new Mutex("GC complete lock"); 267 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 268 *gc_complete_lock_)); 269 last_gc_time_ns_ = NanoTime(); 270 last_gc_size_ = GetBytesAllocated(); 271 272 if (ignore_max_footprint_) { 273 SetIdealFootprint(std::numeric_limits<size_t>::max()); 274 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 275 } 276 CHECK_NE(max_allowed_footprint_, 0U); 277 278 // Create our garbage collectors. 279 for (size_t i = 0; i < 2; ++i) { 280 const bool concurrent = i != 0; 281 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 282 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 283 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 284 } 285 if (kMovingCollector) { 286 // TODO: Clean this up. 287 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 288 semi_space_collector_ = new collector::SemiSpace(this, generational); 289 garbage_collectors_.push_back(semi_space_collector_); 290 } 291 292 if (running_on_valgrind_) { 293 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 294 } 295 296 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 297 LOG(INFO) << "Heap() exiting"; 298 } 299} 300 301void Heap::ChangeAllocator(AllocatorType allocator) { 302 // These two allocators are only used internally and don't have any entrypoints. 303 DCHECK_NE(allocator, kAllocatorTypeLOS); 304 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 305 if (current_allocator_ != allocator) { 306 current_allocator_ = allocator; 307 SetQuickAllocEntryPointsAllocator(current_allocator_); 308 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 309 } 310} 311 312bool Heap::IsCompilingBoot() const { 313 for (const auto& space : continuous_spaces_) { 314 if (space->IsImageSpace()) { 315 return false; 316 } else if (space->IsZygoteSpace()) { 317 return false; 318 } 319 } 320 return true; 321} 322 323bool Heap::HasImageSpace() const { 324 for (const auto& space : continuous_spaces_) { 325 if (space->IsImageSpace()) { 326 return true; 327 } 328 } 329 return false; 330} 331 332void Heap::IncrementDisableMovingGC(Thread* self) { 333 // Need to do this holding the lock to prevent races where the GC is about to run / running when 334 // we attempt to disable it. 335 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 336 MutexLock mu(self, *gc_complete_lock_); 337 ++disable_moving_gc_count_; 338 // TODO: Wait for compacting GC to complete if we ever have a concurrent compacting GC. 339} 340 341void Heap::DecrementDisableMovingGC(Thread* self) { 342 MutexLock mu(self, *gc_complete_lock_); 343 CHECK_GE(disable_moving_gc_count_, 0U); 344 --disable_moving_gc_count_; 345} 346 347void Heap::UpdateProcessState(ProcessState process_state) { 348 if (process_state_ != process_state) { 349 process_state_ = process_state; 350 if (process_state_ == kProcessStateJankPerceptible) { 351 TransitionCollector(post_zygote_collector_type_); 352 } else { 353 TransitionCollector(background_collector_type_); 354 } 355 } else { 356 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 357 } 358} 359 360void Heap::CreateThreadPool() { 361 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 362 if (num_threads != 0) { 363 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 364 } 365} 366 367void Heap::VisitObjects(ObjectVisitorCallback callback, void* arg) { 368 Thread* self = Thread::Current(); 369 // GCs can move objects, so don't allow this. 370 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 371 if (bump_pointer_space_ != nullptr) { 372 // Visit objects in bump pointer space. 373 bump_pointer_space_->Walk(callback, arg); 374 } 375 // TODO: Switch to standard begin and end to use ranged a based loop. 376 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 377 it < end; ++it) { 378 mirror::Object* obj = *it; 379 callback(obj, arg); 380 } 381 GetLiveBitmap()->Walk(callback, arg); 382 self->EndAssertNoThreadSuspension(old_cause); 383} 384 385void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 386 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 387 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 388 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 389 // TODO: Generalize this to n bitmaps? 390 if (space1 == nullptr) { 391 DCHECK(space2 != nullptr); 392 space1 = space2; 393 } 394 if (space2 == nullptr) { 395 DCHECK(space1 != nullptr); 396 space2 = space1; 397 } 398 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 399 large_object_space_->GetLiveObjects(), stack); 400} 401 402void Heap::DeleteThreadPool() { 403 thread_pool_.reset(nullptr); 404} 405 406void Heap::AddSpace(space::Space* space, bool set_as_default) { 407 DCHECK(space != nullptr); 408 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 409 if (space->IsContinuousSpace()) { 410 DCHECK(!space->IsDiscontinuousSpace()); 411 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 412 // Continuous spaces don't necessarily have bitmaps. 413 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 414 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 415 if (live_bitmap != nullptr) { 416 DCHECK(mark_bitmap != nullptr); 417 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 418 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 419 } 420 continuous_spaces_.push_back(continuous_space); 421 if (set_as_default) { 422 if (continuous_space->IsDlMallocSpace()) { 423 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 424 } else if (continuous_space->IsRosAllocSpace()) { 425 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 426 } 427 } 428 // Ensure that spaces remain sorted in increasing order of start address. 429 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 430 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 431 return a->Begin() < b->Begin(); 432 }); 433 } else { 434 DCHECK(space->IsDiscontinuousSpace()); 435 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 436 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 437 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 438 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 439 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 440 discontinuous_spaces_.push_back(discontinuous_space); 441 } 442 if (space->IsAllocSpace()) { 443 alloc_spaces_.push_back(space->AsAllocSpace()); 444 } 445} 446 447void Heap::RemoveSpace(space::Space* space) { 448 DCHECK(space != nullptr); 449 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 450 if (space->IsContinuousSpace()) { 451 DCHECK(!space->IsDiscontinuousSpace()); 452 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 453 // Continuous spaces don't necessarily have bitmaps. 454 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 455 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 456 if (live_bitmap != nullptr) { 457 DCHECK(mark_bitmap != nullptr); 458 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 459 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 460 } 461 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 462 DCHECK(it != continuous_spaces_.end()); 463 continuous_spaces_.erase(it); 464 if (continuous_space == dlmalloc_space_) { 465 dlmalloc_space_ = nullptr; 466 } else if (continuous_space == rosalloc_space_) { 467 rosalloc_space_ = nullptr; 468 } 469 if (continuous_space == main_space_) { 470 main_space_ = nullptr; 471 } 472 } else { 473 DCHECK(space->IsDiscontinuousSpace()); 474 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 475 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 476 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 477 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 478 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 479 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 480 discontinuous_space); 481 DCHECK(it != discontinuous_spaces_.end()); 482 discontinuous_spaces_.erase(it); 483 } 484 if (space->IsAllocSpace()) { 485 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 486 DCHECK(it != alloc_spaces_.end()); 487 alloc_spaces_.erase(it); 488 } 489} 490 491void Heap::RegisterGCAllocation(size_t bytes) { 492 if (this != nullptr) { 493 gc_memory_overhead_.FetchAndAdd(bytes); 494 } 495} 496 497void Heap::RegisterGCDeAllocation(size_t bytes) { 498 if (this != nullptr) { 499 gc_memory_overhead_.FetchAndSub(bytes); 500 } 501} 502 503void Heap::DumpGcPerformanceInfo(std::ostream& os) { 504 // Dump cumulative timings. 505 os << "Dumping cumulative Gc timings\n"; 506 uint64_t total_duration = 0; 507 508 // Dump cumulative loggers for each GC type. 509 uint64_t total_paused_time = 0; 510 for (const auto& collector : garbage_collectors_) { 511 CumulativeLogger& logger = collector->GetCumulativeTimings(); 512 if (logger.GetTotalNs() != 0) { 513 os << Dumpable<CumulativeLogger>(logger); 514 const uint64_t total_ns = logger.GetTotalNs(); 515 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 516 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 517 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 518 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 519 Histogram<uint64_t>::CumulativeData cumulative_data; 520 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 521 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 522 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 523 << collector->GetName() << " freed: " << freed_objects 524 << " objects with total size " << PrettySize(freed_bytes) << "\n" 525 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 526 << PrettySize(freed_bytes / seconds) << "/s\n"; 527 total_duration += total_ns; 528 total_paused_time += total_pause_ns; 529 } 530 } 531 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 532 if (total_duration != 0) { 533 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 534 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 535 os << "Mean GC size throughput: " 536 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 537 os << "Mean GC object throughput: " 538 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 539 } 540 size_t total_objects_allocated = GetObjectsAllocatedEver(); 541 os << "Total number of allocations: " << total_objects_allocated << "\n"; 542 size_t total_bytes_allocated = GetBytesAllocatedEver(); 543 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 544 if (kMeasureAllocationTime) { 545 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 546 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 547 << "\n"; 548 } 549 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 550 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 551 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 552} 553 554Heap::~Heap() { 555 VLOG(heap) << "Starting ~Heap()"; 556 STLDeleteElements(&garbage_collectors_); 557 // If we don't reset then the mark stack complains in its destructor. 558 allocation_stack_->Reset(); 559 live_stack_->Reset(); 560 STLDeleteValues(&mod_union_tables_); 561 STLDeleteElements(&continuous_spaces_); 562 STLDeleteElements(&discontinuous_spaces_); 563 delete gc_complete_lock_; 564 VLOG(heap) << "Finished ~Heap()"; 565} 566 567space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 568 bool fail_ok) const { 569 for (const auto& space : continuous_spaces_) { 570 if (space->Contains(obj)) { 571 return space; 572 } 573 } 574 if (!fail_ok) { 575 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 576 } 577 return NULL; 578} 579 580space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 581 bool fail_ok) const { 582 for (const auto& space : discontinuous_spaces_) { 583 if (space->Contains(obj)) { 584 return space; 585 } 586 } 587 if (!fail_ok) { 588 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 589 } 590 return NULL; 591} 592 593space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 594 space::Space* result = FindContinuousSpaceFromObject(obj, true); 595 if (result != NULL) { 596 return result; 597 } 598 return FindDiscontinuousSpaceFromObject(obj, true); 599} 600 601struct SoftReferenceArgs { 602 RootVisitor* is_marked_callback_; 603 RootVisitor* recursive_mark_callback_; 604 void* arg_; 605}; 606 607mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 608 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 609 // TODO: Not preserve all soft references. 610 return args->recursive_mark_callback_(obj, args->arg_); 611} 612 613// Process reference class instances and schedule finalizations. 614void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 615 RootVisitor* is_marked_callback, 616 RootVisitor* recursive_mark_object_callback, void* arg) { 617 // Unless we are in the zygote or required to clear soft references with white references, 618 // preserve some white referents. 619 if (!clear_soft && !Runtime::Current()->IsZygote()) { 620 SoftReferenceArgs soft_reference_args; 621 soft_reference_args.is_marked_callback_ = is_marked_callback; 622 soft_reference_args.recursive_mark_callback_ = recursive_mark_object_callback; 623 soft_reference_args.arg_ = arg; 624 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 625 &soft_reference_args); 626 } 627 timings.StartSplit("ProcessReferences"); 628 // Clear all remaining soft and weak references with white referents. 629 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 630 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 631 timings.EndSplit(); 632 // Preserve all white objects with finalize methods and schedule them for finalization. 633 timings.StartSplit("EnqueueFinalizerReferences"); 634 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 635 recursive_mark_object_callback, arg); 636 timings.EndSplit(); 637 timings.StartSplit("ProcessReferences"); 638 // Clear all f-reachable soft and weak references with white referents. 639 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 640 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 641 // Clear all phantom references with white referents. 642 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 643 // At this point all reference queues other than the cleared references should be empty. 644 DCHECK(soft_reference_queue_.IsEmpty()); 645 DCHECK(weak_reference_queue_.IsEmpty()); 646 DCHECK(finalizer_reference_queue_.IsEmpty()); 647 DCHECK(phantom_reference_queue_.IsEmpty()); 648 timings.EndSplit(); 649} 650 651bool Heap::IsEnqueued(mirror::Object* ref) const { 652 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 653 // will always be non-null. 654 return ref->GetFieldObject<mirror::Object*>(GetReferencePendingNextOffset(), false) != nullptr; 655} 656 657bool Heap::IsEnqueuable(const mirror::Object* ref) const { 658 DCHECK(ref != nullptr); 659 const mirror::Object* queue = 660 ref->GetFieldObject<mirror::Object*>(GetReferenceQueueOffset(), false); 661 const mirror::Object* queue_next = 662 ref->GetFieldObject<mirror::Object*>(GetReferenceQueueNextOffset(), false); 663 return queue != nullptr && queue_next == nullptr; 664} 665 666// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 667// marked, put it on the appropriate list in the heap for later processing. 668void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 669 RootVisitor mark_visitor, void* arg) { 670 DCHECK(klass != nullptr); 671 DCHECK(klass->IsReferenceClass()); 672 DCHECK(obj != nullptr); 673 mirror::Object* referent = GetReferenceReferent(obj); 674 if (referent != nullptr) { 675 mirror::Object* forward_address = mark_visitor(referent, arg); 676 // Null means that the object is not currently marked. 677 if (forward_address == nullptr) { 678 Thread* self = Thread::Current(); 679 // TODO: Remove these locks, and use atomic stacks for storing references? 680 // We need to check that the references haven't already been enqueued since we can end up 681 // scanning the same reference multiple times due to dirty cards. 682 if (klass->IsSoftReferenceClass()) { 683 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 684 } else if (klass->IsWeakReferenceClass()) { 685 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 686 } else if (klass->IsFinalizerReferenceClass()) { 687 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 688 } else if (klass->IsPhantomReferenceClass()) { 689 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 690 } else { 691 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 692 << klass->GetAccessFlags(); 693 } 694 } else if (referent != forward_address) { 695 // Referent is already marked and we need to update it. 696 SetReferenceReferent(obj, forward_address); 697 } 698 } 699} 700 701space::ImageSpace* Heap::GetImageSpace() const { 702 for (const auto& space : continuous_spaces_) { 703 if (space->IsImageSpace()) { 704 return space->AsImageSpace(); 705 } 706 } 707 return NULL; 708} 709 710static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 711 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 712 if (used_bytes < chunk_size) { 713 size_t chunk_free_bytes = chunk_size - used_bytes; 714 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 715 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 716 } 717} 718 719void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 720 std::ostringstream oss; 721 int64_t total_bytes_free = GetFreeMemory(); 722 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 723 << " free bytes"; 724 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 725 if (!large_object_allocation && total_bytes_free >= byte_count) { 726 size_t max_contiguous_allocation = 0; 727 for (const auto& space : continuous_spaces_) { 728 if (space->IsMallocSpace()) { 729 // To allow the Walk/InspectAll() to exclusively-lock the mutator 730 // lock, temporarily release the shared access to the mutator 731 // lock here by transitioning to the suspended state. 732 Locks::mutator_lock_->AssertSharedHeld(self); 733 self->TransitionFromRunnableToSuspended(kSuspended); 734 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 735 self->TransitionFromSuspendedToRunnable(); 736 Locks::mutator_lock_->AssertSharedHeld(self); 737 } 738 } 739 oss << "; failed due to fragmentation (largest possible contiguous allocation " 740 << max_contiguous_allocation << " bytes)"; 741 } 742 self->ThrowOutOfMemoryError(oss.str().c_str()); 743} 744 745void Heap::Trim() { 746 uint64_t start_ns = NanoTime(); 747 // Trim the managed spaces. 748 uint64_t total_alloc_space_allocated = 0; 749 uint64_t total_alloc_space_size = 0; 750 uint64_t managed_reclaimed = 0; 751 for (const auto& space : continuous_spaces_) { 752 if (space->IsMallocSpace()) { 753 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 754 total_alloc_space_size += alloc_space->Size(); 755 managed_reclaimed += alloc_space->Trim(); 756 } 757 } 758 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 759 bump_pointer_space_->Size(); 760 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 761 static_cast<float>(total_alloc_space_size); 762 uint64_t gc_heap_end_ns = NanoTime(); 763 // Trim the native heap. 764 dlmalloc_trim(0); 765 size_t native_reclaimed = 0; 766 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 767 uint64_t end_ns = NanoTime(); 768 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 769 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 770 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 771 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 772 << "%."; 773} 774 775bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 776 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 777 // taking the lock. 778 if (obj == nullptr) { 779 return true; 780 } 781 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 782} 783 784bool Heap::IsHeapAddress(const mirror::Object* obj) const { 785 if (kMovingCollector && bump_pointer_space_ && bump_pointer_space_->HasAddress(obj)) { 786 return true; 787 } 788 // TODO: This probably doesn't work for large objects. 789 return FindSpaceFromObject(obj, true) != nullptr; 790} 791 792bool Heap::IsLiveObjectLocked(const mirror::Object* obj, bool search_allocation_stack, 793 bool search_live_stack, bool sorted) { 794 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 795 return false; 796 } 797 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 798 mirror::Class* klass = obj->GetClass(); 799 if (obj == klass) { 800 // This case happens for java.lang.Class. 801 return true; 802 } 803 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 804 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 805 return false; 806 } 807 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 808 space::DiscontinuousSpace* d_space = NULL; 809 if (c_space != nullptr) { 810 if (c_space->GetLiveBitmap()->Test(obj)) { 811 return true; 812 } 813 } else { 814 d_space = FindDiscontinuousSpaceFromObject(obj, true); 815 if (d_space != nullptr) { 816 if (d_space->GetLiveObjects()->Test(obj)) { 817 return true; 818 } 819 } 820 } 821 // This is covering the allocation/live stack swapping that is done without mutators suspended. 822 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 823 if (i > 0) { 824 NanoSleep(MsToNs(10)); 825 } 826 if (search_allocation_stack) { 827 if (sorted) { 828 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 829 return true; 830 } 831 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 832 return true; 833 } 834 } 835 836 if (search_live_stack) { 837 if (sorted) { 838 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 839 return true; 840 } 841 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 842 return true; 843 } 844 } 845 } 846 // We need to check the bitmaps again since there is a race where we mark something as live and 847 // then clear the stack containing it. 848 if (c_space != nullptr) { 849 if (c_space->GetLiveBitmap()->Test(obj)) { 850 return true; 851 } 852 } else { 853 d_space = FindDiscontinuousSpaceFromObject(obj, true); 854 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 855 return true; 856 } 857 } 858 return false; 859} 860 861void Heap::VerifyObjectImpl(const mirror::Object* obj) { 862 if (Thread::Current() == NULL || 863 Runtime::Current()->GetThreadList()->GetLockOwner() == Thread::Current()->GetTid()) { 864 return; 865 } 866 VerifyObjectBody(obj); 867} 868 869bool Heap::VerifyClassClass(const mirror::Class* c) const { 870 // Note: we don't use the accessors here as they have internal sanity checks that we don't want 871 // to run 872 const byte* raw_addr = 873 reinterpret_cast<const byte*>(c) + mirror::Object::ClassOffset().Int32Value(); 874 const mirror::Class* c_c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 875 raw_addr = reinterpret_cast<const byte*>(c_c) + mirror::Object::ClassOffset().Int32Value(); 876 const mirror::Class* c_c_c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 877 return c_c == c_c_c; 878} 879 880void Heap::DumpSpaces(std::ostream& stream) { 881 for (const auto& space : continuous_spaces_) { 882 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 883 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 884 stream << space << " " << *space << "\n"; 885 if (live_bitmap != nullptr) { 886 stream << live_bitmap << " " << *live_bitmap << "\n"; 887 } 888 if (mark_bitmap != nullptr) { 889 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 890 } 891 } 892 for (const auto& space : discontinuous_spaces_) { 893 stream << space << " " << *space << "\n"; 894 } 895} 896 897void Heap::VerifyObjectBody(const mirror::Object* obj) { 898 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 899 // Ignore early dawn of the universe verifications. 900 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 901 return; 902 } 903 const byte* raw_addr = reinterpret_cast<const byte*>(obj) + 904 mirror::Object::ClassOffset().Int32Value(); 905 const mirror::Class* c = *reinterpret_cast<mirror::Class* const *>(raw_addr); 906 if (UNLIKELY(c == NULL)) { 907 LOG(FATAL) << "Null class in object: " << obj; 908 } else if (UNLIKELY(!IsAligned<kObjectAlignment>(c))) { 909 LOG(FATAL) << "Class isn't aligned: " << c << " in object: " << obj; 910 } 911 CHECK(VerifyClassClass(c)); 912 913 if (verify_object_mode_ > kVerifyAllFast) { 914 // TODO: the bitmap tests below are racy if VerifyObjectBody is called without the 915 // heap_bitmap_lock_. 916 if (!IsLiveObjectLocked(obj)) { 917 DumpSpaces(); 918 LOG(FATAL) << "Object is dead: " << obj; 919 } 920 if (!IsLiveObjectLocked(c)) { 921 LOG(FATAL) << "Class of object is dead: " << c << " in object: " << obj; 922 } 923 } 924} 925 926void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 927 DCHECK(obj != NULL); 928 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 929} 930 931void Heap::VerifyHeap() { 932 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 933 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 934} 935 936void Heap::RecordFree(int64_t freed_objects, int64_t freed_bytes) { 937 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 938 num_bytes_allocated_.FetchAndSub(freed_bytes); 939 if (Runtime::Current()->HasStatsEnabled()) { 940 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 941 thread_stats->freed_objects += freed_objects; 942 thread_stats->freed_bytes += freed_bytes; 943 // TODO: Do this concurrently. 944 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 945 global_stats->freed_objects += freed_objects; 946 global_stats->freed_bytes += freed_bytes; 947 } 948} 949 950mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 951 size_t alloc_size, size_t* bytes_allocated, 952 mirror::Class** klass) { 953 mirror::Object* ptr = nullptr; 954 bool was_default_allocator = allocator == GetCurrentAllocator(); 955 DCHECK(klass != nullptr); 956 SirtRef<mirror::Class> sirt_klass(self, *klass); 957 // The allocation failed. If the GC is running, block until it completes, and then retry the 958 // allocation. 959 collector::GcType last_gc = WaitForGcToComplete(self); 960 if (last_gc != collector::kGcTypeNone) { 961 // If we were the default allocator but the allocator changed while we were suspended, 962 // abort the allocation. 963 if (was_default_allocator && allocator != GetCurrentAllocator()) { 964 *klass = sirt_klass.get(); 965 return nullptr; 966 } 967 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 968 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 969 } 970 971 // Loop through our different Gc types and try to Gc until we get enough free memory. 972 for (collector::GcType gc_type : gc_plan_) { 973 if (ptr != nullptr) { 974 break; 975 } 976 // Attempt to run the collector, if we succeed, re-try the allocation. 977 bool gc_ran = 978 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 979 if (was_default_allocator && allocator != GetCurrentAllocator()) { 980 *klass = sirt_klass.get(); 981 return nullptr; 982 } 983 if (gc_ran) { 984 // Did we free sufficient memory for the allocation to succeed? 985 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 986 } 987 } 988 // Allocations have failed after GCs; this is an exceptional state. 989 if (ptr == nullptr) { 990 // Try harder, growing the heap if necessary. 991 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 992 } 993 if (ptr == nullptr) { 994 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 995 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 996 // VM spec requires that all SoftReferences have been collected and cleared before throwing 997 // OOME. 998 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 999 << " allocation"; 1000 // TODO: Run finalization, but this may cause more allocations to occur. 1001 // We don't need a WaitForGcToComplete here either. 1002 DCHECK(!gc_plan_.empty()); 1003 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1004 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1005 *klass = sirt_klass.get(); 1006 return nullptr; 1007 } 1008 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1009 if (ptr == nullptr) { 1010 ThrowOutOfMemoryError(self, alloc_size, false); 1011 } 1012 } 1013 *klass = sirt_klass.get(); 1014 return ptr; 1015} 1016 1017void Heap::SetTargetHeapUtilization(float target) { 1018 DCHECK_GT(target, 0.0f); // asserted in Java code 1019 DCHECK_LT(target, 1.0f); 1020 target_utilization_ = target; 1021} 1022 1023size_t Heap::GetObjectsAllocated() const { 1024 size_t total = 0; 1025 for (space::AllocSpace* space : alloc_spaces_) { 1026 total += space->GetObjectsAllocated(); 1027 } 1028 return total; 1029} 1030 1031size_t Heap::GetObjectsAllocatedEver() const { 1032 return GetObjectsFreedEver() + GetObjectsAllocated(); 1033} 1034 1035size_t Heap::GetBytesAllocatedEver() const { 1036 return GetBytesFreedEver() + GetBytesAllocated(); 1037} 1038 1039class InstanceCounter { 1040 public: 1041 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1042 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1043 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1044 } 1045 1046 void operator()(const mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1047 for (size_t i = 0; i < classes_.size(); ++i) { 1048 const mirror::Class* instance_class = o->GetClass(); 1049 if (use_is_assignable_from_) { 1050 if (instance_class != NULL && classes_[i]->IsAssignableFrom(instance_class)) { 1051 ++counts_[i]; 1052 } 1053 } else { 1054 if (instance_class == classes_[i]) { 1055 ++counts_[i]; 1056 } 1057 } 1058 } 1059 } 1060 1061 private: 1062 const std::vector<mirror::Class*>& classes_; 1063 bool use_is_assignable_from_; 1064 uint64_t* const counts_; 1065 1066 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1067}; 1068 1069void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1070 uint64_t* counts) { 1071 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1072 // is empty, so the live bitmap is the only place we need to look. 1073 Thread* self = Thread::Current(); 1074 self->TransitionFromRunnableToSuspended(kNative); 1075 CollectGarbage(false); 1076 self->TransitionFromSuspendedToRunnable(); 1077 1078 InstanceCounter counter(classes, use_is_assignable_from, counts); 1079 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1080 GetLiveBitmap()->Visit(counter); 1081} 1082 1083class InstanceCollector { 1084 public: 1085 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1086 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1087 : class_(c), max_count_(max_count), instances_(instances) { 1088 } 1089 1090 void operator()(const mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1091 const mirror::Class* instance_class = o->GetClass(); 1092 if (instance_class == class_) { 1093 if (max_count_ == 0 || instances_.size() < max_count_) { 1094 instances_.push_back(const_cast<mirror::Object*>(o)); 1095 } 1096 } 1097 } 1098 1099 private: 1100 mirror::Class* class_; 1101 uint32_t max_count_; 1102 std::vector<mirror::Object*>& instances_; 1103 1104 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1105}; 1106 1107void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1108 std::vector<mirror::Object*>& instances) { 1109 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1110 // is empty, so the live bitmap is the only place we need to look. 1111 Thread* self = Thread::Current(); 1112 self->TransitionFromRunnableToSuspended(kNative); 1113 CollectGarbage(false); 1114 self->TransitionFromSuspendedToRunnable(); 1115 1116 InstanceCollector collector(c, max_count, instances); 1117 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1118 GetLiveBitmap()->Visit(collector); 1119} 1120 1121class ReferringObjectsFinder { 1122 public: 1123 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1124 std::vector<mirror::Object*>& referring_objects) 1125 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1126 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1127 } 1128 1129 // For bitmap Visit. 1130 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1131 // annotalysis on visitors. 1132 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1133 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1134 } 1135 1136 // For MarkSweep::VisitObjectReferences. 1137 void operator()(mirror::Object* referrer, mirror::Object* object, 1138 const MemberOffset&, bool) const { 1139 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1140 referring_objects_.push_back(referrer); 1141 } 1142 } 1143 1144 private: 1145 mirror::Object* object_; 1146 uint32_t max_count_; 1147 std::vector<mirror::Object*>& referring_objects_; 1148 1149 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1150}; 1151 1152void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1153 std::vector<mirror::Object*>& referring_objects) { 1154 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1155 // is empty, so the live bitmap is the only place we need to look. 1156 Thread* self = Thread::Current(); 1157 self->TransitionFromRunnableToSuspended(kNative); 1158 CollectGarbage(false); 1159 self->TransitionFromSuspendedToRunnable(); 1160 1161 ReferringObjectsFinder finder(o, max_count, referring_objects); 1162 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1163 GetLiveBitmap()->Visit(finder); 1164} 1165 1166void Heap::CollectGarbage(bool clear_soft_references) { 1167 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1168 // last GC will not have necessarily been cleared. 1169 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1170} 1171 1172void Heap::TransitionCollector(CollectorType collector_type) { 1173 if (collector_type == collector_type_) { 1174 return; 1175 } 1176 uint64_t start_time = NanoTime(); 1177 int32_t before_size = GetTotalMemory(); 1178 int32_t before_allocated = num_bytes_allocated_.Load(); 1179 ThreadList* tl = Runtime::Current()->GetThreadList(); 1180 Thread* self = Thread::Current(); 1181 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1182 Locks::mutator_lock_->AssertNotHeld(self); 1183 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1184 // compacting_gc_disable_count_, this should rarely occurs). 1185 bool copying_transition = 1186 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1187 while (!StartGC(self, copying_transition)) { 1188 usleep(100); 1189 } 1190 tl->SuspendAll(); 1191 switch (collector_type) { 1192 case kCollectorTypeSS: 1193 // Fall-through. 1194 case kCollectorTypeGSS: { 1195 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1196 CHECK(main_space_ != nullptr); 1197 Compact(temp_space_, main_space_); 1198 DCHECK(allocator_mem_map_.get() == nullptr); 1199 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1200 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1201 // RemoveSpace does not delete the removed space. 1202 space::Space* old_space = main_space_; 1203 RemoveSpace(old_space); 1204 delete old_space; 1205 break; 1206 } 1207 case kCollectorTypeMS: 1208 // Fall through. 1209 case kCollectorTypeCMS: { 1210 if (IsCompactingGC(collector_type_)) { 1211 // TODO: Use mem-map from temp space? 1212 MemMap* mem_map = allocator_mem_map_.release(); 1213 CHECK(mem_map != nullptr); 1214 size_t initial_size = kDefaultInitialSize; 1215 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1216 CHECK(main_space_ == nullptr); 1217 if (kUseRosAlloc) { 1218 main_space_ = 1219 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1220 initial_size, mem_map->Size(), 1221 mem_map->Size(), low_memory_mode_); 1222 } else { 1223 main_space_ = 1224 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1225 initial_size, mem_map->Size(), 1226 mem_map->Size()); 1227 } 1228 main_space_->SetFootprintLimit(main_space_->Capacity()); 1229 AddSpace(main_space_); 1230 Compact(main_space_, bump_pointer_space_); 1231 } 1232 break; 1233 } 1234 default: { 1235 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1236 break; 1237 } 1238 } 1239 ChangeCollector(collector_type); 1240 tl->ResumeAll(); 1241 // Can't call into java code with all threads suspended. 1242 EnqueueClearedReferences(); 1243 uint64_t duration = NanoTime() - start_time; 1244 GrowForUtilization(collector::kGcTypeFull, duration); 1245 FinishGC(self, collector::kGcTypeFull); 1246 int32_t after_size = GetTotalMemory(); 1247 int32_t delta_size = before_size - after_size; 1248 int32_t after_allocated = num_bytes_allocated_.Load(); 1249 int32_t delta_allocated = before_allocated - after_allocated; 1250 const std::string saved_bytes_str = 1251 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1252 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1253 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1254 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1255 << PrettySize(delta_size) << " saved"; 1256} 1257 1258void Heap::ChangeCollector(CollectorType collector_type) { 1259 // TODO: Only do this with all mutators suspended to avoid races. 1260 if (collector_type != collector_type_) { 1261 collector_type_ = collector_type; 1262 gc_plan_.clear(); 1263 switch (collector_type_) { 1264 case kCollectorTypeSS: 1265 // Fall-through. 1266 case kCollectorTypeGSS: { 1267 concurrent_gc_ = false; 1268 gc_plan_.push_back(collector::kGcTypeFull); 1269 if (use_tlab_) { 1270 ChangeAllocator(kAllocatorTypeTLAB); 1271 } else { 1272 ChangeAllocator(kAllocatorTypeBumpPointer); 1273 } 1274 break; 1275 } 1276 case kCollectorTypeMS: { 1277 concurrent_gc_ = false; 1278 gc_plan_.push_back(collector::kGcTypeSticky); 1279 gc_plan_.push_back(collector::kGcTypePartial); 1280 gc_plan_.push_back(collector::kGcTypeFull); 1281 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1282 break; 1283 } 1284 case kCollectorTypeCMS: { 1285 concurrent_gc_ = true; 1286 gc_plan_.push_back(collector::kGcTypeSticky); 1287 gc_plan_.push_back(collector::kGcTypePartial); 1288 gc_plan_.push_back(collector::kGcTypeFull); 1289 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1290 break; 1291 } 1292 default: { 1293 LOG(FATAL) << "Unimplemented"; 1294 } 1295 } 1296 if (concurrent_gc_) { 1297 concurrent_start_bytes_ = 1298 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1299 } else { 1300 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1301 } 1302 } 1303} 1304 1305// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1306class ZygoteCompactingCollector : public collector::SemiSpace { 1307 public: 1308 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector") { 1309 } 1310 1311 void BuildBins(space::ContinuousSpace* space) { 1312 bin_live_bitmap_ = space->GetLiveBitmap(); 1313 bin_mark_bitmap_ = space->GetMarkBitmap(); 1314 BinContext context; 1315 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1316 context.collector_ = this; 1317 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1318 // Note: This requires traversing the space in increasing order of object addresses. 1319 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1320 // Add the last bin which spans after the last object to the end of the space. 1321 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1322 } 1323 1324 private: 1325 struct BinContext { 1326 uintptr_t prev_; // The end of the previous object. 1327 ZygoteCompactingCollector* collector_; 1328 }; 1329 // Maps from bin sizes to locations. 1330 std::multimap<size_t, uintptr_t> bins_; 1331 // Live bitmap of the space which contains the bins. 1332 accounting::SpaceBitmap* bin_live_bitmap_; 1333 // Mark bitmap of the space which contains the bins. 1334 accounting::SpaceBitmap* bin_mark_bitmap_; 1335 1336 static void Callback(mirror::Object* obj, void* arg) 1337 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1338 DCHECK(arg != nullptr); 1339 BinContext* context = reinterpret_cast<BinContext*>(arg); 1340 ZygoteCompactingCollector* collector = context->collector_; 1341 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1342 size_t bin_size = object_addr - context->prev_; 1343 // Add the bin consisting of the end of the previous object to the start of the current object. 1344 collector->AddBin(bin_size, context->prev_); 1345 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1346 } 1347 1348 void AddBin(size_t size, uintptr_t position) { 1349 if (size != 0) { 1350 bins_.insert(std::make_pair(size, position)); 1351 } 1352 } 1353 1354 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1355 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1356 // allocator. 1357 return false; 1358 } 1359 1360 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1361 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1362 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1363 mirror::Object* forward_address; 1364 // Find the smallest bin which we can move obj in. 1365 auto it = bins_.lower_bound(object_size); 1366 if (it == bins_.end()) { 1367 // No available space in the bins, place it in the target space instead (grows the zygote 1368 // space). 1369 size_t bytes_allocated; 1370 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated); 1371 if (to_space_live_bitmap_ != nullptr) { 1372 to_space_live_bitmap_->Set(forward_address); 1373 } else { 1374 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1375 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1376 } 1377 } else { 1378 size_t size = it->first; 1379 uintptr_t pos = it->second; 1380 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1381 forward_address = reinterpret_cast<mirror::Object*>(pos); 1382 // Set the live and mark bits so that sweeping system weaks works properly. 1383 bin_live_bitmap_->Set(forward_address); 1384 bin_mark_bitmap_->Set(forward_address); 1385 DCHECK_GE(size, object_size); 1386 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1387 } 1388 // Copy the object over to its new location. 1389 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1390 return forward_address; 1391 } 1392}; 1393 1394void Heap::UnBindBitmaps() { 1395 for (const auto& space : GetContinuousSpaces()) { 1396 if (space->IsContinuousMemMapAllocSpace()) { 1397 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1398 if (alloc_space->HasBoundBitmaps()) { 1399 alloc_space->UnBindBitmaps(); 1400 } 1401 } 1402 } 1403} 1404 1405void Heap::PreZygoteFork() { 1406 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1407 Thread* self = Thread::Current(); 1408 MutexLock mu(self, zygote_creation_lock_); 1409 // Try to see if we have any Zygote spaces. 1410 if (have_zygote_space_) { 1411 return; 1412 } 1413 VLOG(heap) << "Starting PreZygoteFork"; 1414 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1415 // Trim the pages at the end of the non moving space. 1416 non_moving_space_->Trim(); 1417 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1418 // Change the collector to the post zygote one. 1419 ChangeCollector(post_zygote_collector_type_); 1420 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1421 if (semi_space_collector_ != nullptr) { 1422 ZygoteCompactingCollector zygote_collector(this); 1423 zygote_collector.BuildBins(non_moving_space_); 1424 // Create a new bump pointer space which we will compact into. 1425 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1426 non_moving_space_->Limit()); 1427 // Compact the bump pointer space to a new zygote bump pointer space. 1428 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1429 zygote_collector.SetFromSpace(bump_pointer_space_); 1430 zygote_collector.SetToSpace(&target_space); 1431 zygote_collector.Run(kGcCauseCollectorTransition, false); 1432 CHECK(temp_space_->IsEmpty()); 1433 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1434 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1435 // Update the end and write out image. 1436 non_moving_space_->SetEnd(target_space.End()); 1437 non_moving_space_->SetLimit(target_space.Limit()); 1438 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1439 } 1440 // Save the old space so that we can remove it after we complete creating the zygote space. 1441 space::MallocSpace* old_alloc_space = non_moving_space_; 1442 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1443 // the remaining available space. 1444 // Remove the old space before creating the zygote space since creating the zygote space sets 1445 // the old alloc space's bitmaps to nullptr. 1446 RemoveSpace(old_alloc_space); 1447 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1448 low_memory_mode_, 1449 &main_space_); 1450 delete old_alloc_space; 1451 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1452 AddSpace(zygote_space, false); 1453 CHECK(main_space_ != nullptr); 1454 if (main_space_->IsRosAllocSpace()) { 1455 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1456 } else if (main_space_->IsDlMallocSpace()) { 1457 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1458 } 1459 main_space_->SetFootprintLimit(main_space_->Capacity()); 1460 AddSpace(main_space_); 1461 have_zygote_space_ = true; 1462 // Create the zygote space mod union table. 1463 accounting::ModUnionTable* mod_union_table = 1464 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1465 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1466 AddModUnionTable(mod_union_table); 1467 // Reset the cumulative loggers since we now have a few additional timing phases. 1468 for (const auto& collector : garbage_collectors_) { 1469 collector->ResetCumulativeStatistics(); 1470 } 1471 // Can't use RosAlloc for non moving space due to thread local buffers. 1472 // TODO: Non limited space for non-movable objects? 1473 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1474 space::MallocSpace* new_non_moving_space = 1475 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1476 2 * MB, mem_map->Size(), mem_map->Size()); 1477 AddSpace(new_non_moving_space, false); 1478 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1479 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1480 non_moving_space_ = new_non_moving_space; 1481} 1482 1483void Heap::FlushAllocStack() { 1484 MarkAllocStackAsLive(allocation_stack_.get()); 1485 allocation_stack_->Reset(); 1486} 1487 1488void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1489 accounting::SpaceBitmap* bitmap2, 1490 accounting::ObjectSet* large_objects, 1491 accounting::ObjectStack* stack) { 1492 DCHECK(bitmap1 != nullptr); 1493 DCHECK(bitmap2 != nullptr); 1494 mirror::Object** limit = stack->End(); 1495 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1496 const mirror::Object* obj = *it; 1497 DCHECK(obj != nullptr); 1498 if (bitmap1->HasAddress(obj)) { 1499 bitmap1->Set(obj); 1500 } else if (bitmap2->HasAddress(obj)) { 1501 bitmap2->Set(obj); 1502 } else { 1503 large_objects->Set(obj); 1504 } 1505 } 1506} 1507 1508void Heap::SwapSemiSpaces() { 1509 // Swap the spaces so we allocate into the space which we just evacuated. 1510 std::swap(bump_pointer_space_, temp_space_); 1511} 1512 1513void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1514 space::ContinuousMemMapAllocSpace* source_space) { 1515 CHECK(kMovingCollector); 1516 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1517 if (target_space != source_space) { 1518 semi_space_collector_->SetFromSpace(source_space); 1519 semi_space_collector_->SetToSpace(target_space); 1520 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1521 } 1522} 1523 1524collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1525 bool clear_soft_references) { 1526 Thread* self = Thread::Current(); 1527 Runtime* runtime = Runtime::Current(); 1528 // If the heap can't run the GC, silently fail and return that no GC was run. 1529 switch (gc_type) { 1530 case collector::kGcTypePartial: { 1531 if (!have_zygote_space_) { 1532 return collector::kGcTypeNone; 1533 } 1534 break; 1535 } 1536 default: { 1537 // Other GC types don't have any special cases which makes them not runnable. The main case 1538 // here is full GC. 1539 } 1540 } 1541 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1542 Locks::mutator_lock_->AssertNotHeld(self); 1543 if (self->IsHandlingStackOverflow()) { 1544 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1545 } 1546 gc_complete_lock_->AssertNotHeld(self); 1547 const bool compacting_gc = IsCompactingGC(collector_type_); 1548 if (!StartGC(self, compacting_gc)) { 1549 return collector::kGcTypeNone; 1550 } 1551 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1552 ++runtime->GetStats()->gc_for_alloc_count; 1553 ++self->GetStats()->gc_for_alloc_count; 1554 } 1555 uint64_t gc_start_time_ns = NanoTime(); 1556 uint64_t gc_start_size = GetBytesAllocated(); 1557 // Approximate allocation rate in bytes / second. 1558 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1559 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1560 if (LIKELY(ms_delta != 0)) { 1561 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1562 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1563 } 1564 1565 DCHECK_LT(gc_type, collector::kGcTypeMax); 1566 DCHECK_NE(gc_type, collector::kGcTypeNone); 1567 1568 collector::GarbageCollector* collector = nullptr; 1569 // TODO: Clean this up. 1570 if (compacting_gc) { 1571 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1572 current_allocator_ == kAllocatorTypeTLAB); 1573 gc_type = semi_space_collector_->GetGcType(); 1574 CHECK(temp_space_->IsEmpty()); 1575 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1576 semi_space_collector_->SetToSpace(temp_space_); 1577 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1578 collector = semi_space_collector_; 1579 gc_type = collector::kGcTypeFull; 1580 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1581 current_allocator_ == kAllocatorTypeDlMalloc) { 1582 for (const auto& cur_collector : garbage_collectors_) { 1583 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1584 cur_collector->GetGcType() == gc_type) { 1585 collector = cur_collector; 1586 break; 1587 } 1588 } 1589 } else { 1590 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1591 } 1592 CHECK(collector != nullptr) 1593 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1594 << " and type=" << gc_type; 1595 1596 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1597 1598 collector->Run(gc_cause, clear_soft_references); 1599 total_objects_freed_ever_ += collector->GetFreedObjects(); 1600 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1601 1602 // Enqueue cleared references. 1603 Locks::mutator_lock_->AssertNotHeld(self); 1604 EnqueueClearedReferences(); 1605 1606 // Grow the heap so that we know when to perform the next GC. 1607 GrowForUtilization(gc_type, collector->GetDurationNs()); 1608 1609 if (CareAboutPauseTimes()) { 1610 const size_t duration = collector->GetDurationNs(); 1611 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1612 // GC for alloc pauses the allocating thread, so consider it as a pause. 1613 bool was_slow = duration > long_gc_log_threshold_ || 1614 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1615 if (!was_slow) { 1616 for (uint64_t pause : pauses) { 1617 was_slow = was_slow || pause > long_pause_log_threshold_; 1618 } 1619 } 1620 if (was_slow) { 1621 const size_t percent_free = GetPercentFree(); 1622 const size_t current_heap_size = GetBytesAllocated(); 1623 const size_t total_memory = GetTotalMemory(); 1624 std::ostringstream pause_string; 1625 for (size_t i = 0; i < pauses.size(); ++i) { 1626 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1627 << ((i != pauses.size() - 1) ? ", " : ""); 1628 } 1629 LOG(INFO) << gc_cause << " " << collector->GetName() 1630 << " GC freed " << collector->GetFreedObjects() << "(" 1631 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1632 << collector->GetFreedLargeObjects() << "(" 1633 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1634 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1635 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1636 << " total " << PrettyDuration((duration / 1000) * 1000); 1637 if (VLOG_IS_ON(heap)) { 1638 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1639 } 1640 } 1641 } 1642 FinishGC(self, gc_type); 1643 ATRACE_END(); 1644 1645 // Inform DDMS that a GC completed. 1646 Dbg::GcDidFinish(); 1647 return gc_type; 1648} 1649 1650bool Heap::StartGC(Thread* self, bool is_compacting) { 1651 MutexLock mu(self, *gc_complete_lock_); 1652 // Ensure there is only one GC at a time. 1653 WaitForGcToCompleteLocked(self); 1654 // TODO: if another thread beat this one to do the GC, perhaps we should just return here? 1655 // Not doing at the moment to ensure soft references are cleared. 1656 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1657 if (is_compacting && disable_moving_gc_count_ != 0) { 1658 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1659 return false; 1660 } 1661 is_gc_running_ = true; 1662 return true; 1663} 1664 1665void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1666 MutexLock mu(self, *gc_complete_lock_); 1667 is_gc_running_ = false; 1668 last_gc_type_ = gc_type; 1669 // Wake anyone who may have been waiting for the GC to complete. 1670 gc_complete_cond_->Broadcast(self); 1671} 1672 1673static mirror::Object* RootMatchesObjectVisitor(mirror::Object* root, void* arg) { 1674 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1675 if (root == obj) { 1676 LOG(INFO) << "Object " << obj << " is a root"; 1677 } 1678 return root; 1679} 1680 1681class ScanVisitor { 1682 public: 1683 void operator()(const mirror::Object* obj) const { 1684 LOG(ERROR) << "Would have rescanned object " << obj; 1685 } 1686}; 1687 1688// Verify a reference from an object. 1689class VerifyReferenceVisitor { 1690 public: 1691 explicit VerifyReferenceVisitor(Heap* heap) 1692 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1693 : heap_(heap), failed_(false) {} 1694 1695 bool Failed() const { 1696 return failed_; 1697 } 1698 1699 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1700 // analysis on visitors. 1701 void operator()(const mirror::Object* obj, const mirror::Object* ref, 1702 const MemberOffset& offset, bool /* is_static */) const 1703 NO_THREAD_SAFETY_ANALYSIS { 1704 if (ref == nullptr || IsLive(ref)) { 1705 // Verify that the reference is live. 1706 return; 1707 } 1708 if (!failed_) { 1709 // Print message on only on first failure to prevent spam. 1710 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1711 failed_ = true; 1712 } 1713 if (obj != nullptr) { 1714 accounting::CardTable* card_table = heap_->GetCardTable(); 1715 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1716 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1717 byte* card_addr = card_table->CardFromAddr(obj); 1718 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1719 << offset << "\n card value = " << static_cast<int>(*card_addr); 1720 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1721 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1722 } else { 1723 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1724 } 1725 1726 // Attmept to find the class inside of the recently freed objects. 1727 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1728 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1729 space::MallocSpace* space = ref_space->AsMallocSpace(); 1730 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1731 if (ref_class != nullptr) { 1732 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1733 << PrettyClass(ref_class); 1734 } else { 1735 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1736 } 1737 } 1738 1739 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1740 ref->GetClass()->IsClass()) { 1741 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1742 } else { 1743 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1744 << ") is not a valid heap address"; 1745 } 1746 1747 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1748 void* cover_begin = card_table->AddrFromCard(card_addr); 1749 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1750 accounting::CardTable::kCardSize); 1751 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1752 << "-" << cover_end; 1753 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1754 1755 if (bitmap == nullptr) { 1756 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1757 if (!heap_->VerifyClassClass(obj->GetClass())) { 1758 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1759 } 1760 } else { 1761 // Print out how the object is live. 1762 if (bitmap->Test(obj)) { 1763 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1764 } 1765 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1766 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1767 } 1768 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1769 LOG(ERROR) << "Object " << obj << " found in live stack"; 1770 } 1771 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1772 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1773 } 1774 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1775 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1776 } 1777 // Attempt to see if the card table missed the reference. 1778 ScanVisitor scan_visitor; 1779 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1780 card_table->Scan(bitmap, byte_cover_begin, 1781 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1782 } 1783 1784 // Search to see if any of the roots reference our object. 1785 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1786 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1787 1788 // Search to see if any of the roots reference our reference. 1789 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1790 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1791 } else { 1792 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 1793 } 1794 } 1795 1796 bool IsLive(const mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1797 return heap_->IsLiveObjectLocked(obj, true, false, true); 1798 } 1799 1800 static mirror::Object* VerifyRoots(mirror::Object* root, void* arg) { 1801 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1802 (*visitor)(nullptr, root, MemberOffset(0), true); 1803 return root; 1804 } 1805 1806 private: 1807 Heap* const heap_; 1808 mutable bool failed_; 1809}; 1810 1811// Verify all references within an object, for use with HeapBitmap::Visit. 1812class VerifyObjectVisitor { 1813 public: 1814 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1815 1816 void operator()(mirror::Object* obj) const 1817 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1818 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1819 // be live or else how did we find it in the live bitmap? 1820 VerifyReferenceVisitor visitor(heap_); 1821 // The class doesn't count as a reference but we should verify it anyways. 1822 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1823 if (obj->GetClass()->IsReferenceClass()) { 1824 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1825 } 1826 failed_ = failed_ || visitor.Failed(); 1827 } 1828 1829 static void VisitCallback(mirror::Object* obj, void* arg) 1830 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1831 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1832 visitor->operator()(obj); 1833 } 1834 1835 bool Failed() const { 1836 return failed_; 1837 } 1838 1839 private: 1840 Heap* const heap_; 1841 mutable bool failed_; 1842}; 1843 1844// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1845bool Heap::VerifyHeapReferences() { 1846 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1847 // Lets sort our allocation stacks so that we can efficiently binary search them. 1848 allocation_stack_->Sort(); 1849 live_stack_->Sort(); 1850 VerifyObjectVisitor visitor(this); 1851 // Verify objects in the allocation stack since these will be objects which were: 1852 // 1. Allocated prior to the GC (pre GC verification). 1853 // 2. Allocated during the GC (pre sweep GC verification). 1854 // We don't want to verify the objects in the live stack since they themselves may be 1855 // pointing to dead objects if they are not reachable. 1856 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1857 // Verify the roots: 1858 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1859 if (visitor.Failed()) { 1860 // Dump mod-union tables. 1861 for (const auto& table_pair : mod_union_tables_) { 1862 accounting::ModUnionTable* mod_union_table = table_pair.second; 1863 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1864 } 1865 DumpSpaces(); 1866 return false; 1867 } 1868 return true; 1869} 1870 1871class VerifyReferenceCardVisitor { 1872 public: 1873 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1874 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1875 Locks::heap_bitmap_lock_) 1876 : heap_(heap), failed_(failed) { 1877 } 1878 1879 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1880 // annotalysis on visitors. 1881 void operator()(const mirror::Object* obj, const mirror::Object* ref, const MemberOffset& offset, 1882 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1883 // Filter out class references since changing an object's class does not mark the card as dirty. 1884 // Also handles large objects, since the only reference they hold is a class reference. 1885 if (ref != NULL && !ref->IsClass()) { 1886 accounting::CardTable* card_table = heap_->GetCardTable(); 1887 // If the object is not dirty and it is referencing something in the live stack other than 1888 // class, then it must be on a dirty card. 1889 if (!card_table->AddrIsInCardTable(obj)) { 1890 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1891 *failed_ = true; 1892 } else if (!card_table->IsDirty(obj)) { 1893 // TODO: Check mod-union tables. 1894 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1895 // kCardDirty - 1 if it didnt get touched since we aged it. 1896 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1897 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1898 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1899 LOG(ERROR) << "Object " << obj << " found in live stack"; 1900 } 1901 if (heap_->GetLiveBitmap()->Test(obj)) { 1902 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1903 } 1904 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1905 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1906 1907 // Print which field of the object is dead. 1908 if (!obj->IsObjectArray()) { 1909 const mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1910 CHECK(klass != NULL); 1911 const mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1912 : klass->GetIFields(); 1913 CHECK(fields != NULL); 1914 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1915 const mirror::ArtField* cur = fields->Get(i); 1916 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1917 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1918 << PrettyField(cur); 1919 break; 1920 } 1921 } 1922 } else { 1923 const mirror::ObjectArray<mirror::Object>* object_array = 1924 obj->AsObjectArray<mirror::Object>(); 1925 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1926 if (object_array->Get(i) == ref) { 1927 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1928 } 1929 } 1930 } 1931 1932 *failed_ = true; 1933 } 1934 } 1935 } 1936 } 1937 1938 private: 1939 Heap* const heap_; 1940 bool* const failed_; 1941}; 1942 1943class VerifyLiveStackReferences { 1944 public: 1945 explicit VerifyLiveStackReferences(Heap* heap) 1946 : heap_(heap), 1947 failed_(false) {} 1948 1949 void operator()(mirror::Object* obj) const 1950 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1951 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1952 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1953 } 1954 1955 bool Failed() const { 1956 return failed_; 1957 } 1958 1959 private: 1960 Heap* const heap_; 1961 bool failed_; 1962}; 1963 1964bool Heap::VerifyMissingCardMarks() { 1965 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1966 1967 // We need to sort the live stack since we binary search it. 1968 live_stack_->Sort(); 1969 VerifyLiveStackReferences visitor(this); 1970 GetLiveBitmap()->Visit(visitor); 1971 1972 // We can verify objects in the live stack since none of these should reference dead objects. 1973 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 1974 visitor(*it); 1975 } 1976 1977 if (visitor.Failed()) { 1978 DumpSpaces(); 1979 return false; 1980 } 1981 return true; 1982} 1983 1984void Heap::SwapStacks() { 1985 allocation_stack_.swap(live_stack_); 1986} 1987 1988accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 1989 auto it = mod_union_tables_.find(space); 1990 if (it == mod_union_tables_.end()) { 1991 return nullptr; 1992 } 1993 return it->second; 1994} 1995 1996void Heap::ProcessCards(TimingLogger& timings) { 1997 // Clear cards and keep track of cards cleared in the mod-union table. 1998 for (const auto& space : continuous_spaces_) { 1999 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2000 if (table != nullptr) { 2001 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2002 "ImageModUnionClearCards"; 2003 TimingLogger::ScopedSplit split(name, &timings); 2004 table->ClearCards(); 2005 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2006 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2007 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2008 // were dirty before the GC started. 2009 // TODO: Don't need to use atomic. 2010 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2011 // roots and then we scan / update mod union tables after. We will always scan either card. 2012 // If we end up with the non aged card, we scan it it in the pause. 2013 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2014 } 2015 } 2016} 2017 2018static mirror::Object* IdentityCallback(mirror::Object* obj, void*) { 2019 return obj; 2020} 2021 2022void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2023 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2024 Thread* self = Thread::Current(); 2025 2026 if (verify_pre_gc_heap_) { 2027 thread_list->SuspendAll(); 2028 { 2029 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2030 if (!VerifyHeapReferences()) { 2031 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2032 } 2033 } 2034 thread_list->ResumeAll(); 2035 } 2036 2037 // Check that all objects which reference things in the live stack are on dirty cards. 2038 if (verify_missing_card_marks_) { 2039 thread_list->SuspendAll(); 2040 { 2041 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2042 SwapStacks(); 2043 // Sort the live stack so that we can quickly binary search it later. 2044 if (!VerifyMissingCardMarks()) { 2045 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2046 } 2047 SwapStacks(); 2048 } 2049 thread_list->ResumeAll(); 2050 } 2051 2052 if (verify_mod_union_table_) { 2053 thread_list->SuspendAll(); 2054 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2055 for (const auto& table_pair : mod_union_tables_) { 2056 accounting::ModUnionTable* mod_union_table = table_pair.second; 2057 mod_union_table->UpdateAndMarkReferences(IdentityCallback, nullptr); 2058 mod_union_table->Verify(); 2059 } 2060 thread_list->ResumeAll(); 2061 } 2062} 2063 2064void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2065 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2066 // reachable objects. 2067 if (verify_post_gc_heap_) { 2068 Thread* self = Thread::Current(); 2069 CHECK_NE(self->GetState(), kRunnable); 2070 { 2071 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2072 // Swapping bound bitmaps does nothing. 2073 gc->SwapBitmaps(); 2074 if (!VerifyHeapReferences()) { 2075 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2076 } 2077 gc->SwapBitmaps(); 2078 } 2079 } 2080} 2081 2082void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2083 if (verify_system_weaks_) { 2084 Thread* self = Thread::Current(); 2085 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2086 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2087 mark_sweep->VerifySystemWeaks(); 2088 } 2089} 2090 2091collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2092 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2093 MutexLock mu(self, *gc_complete_lock_); 2094 return WaitForGcToCompleteLocked(self); 2095} 2096 2097collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2098 collector::GcType last_gc_type = collector::kGcTypeNone; 2099 uint64_t wait_start = NanoTime(); 2100 while (is_gc_running_) { 2101 ATRACE_BEGIN("GC: Wait For Completion"); 2102 // We must wait, change thread state then sleep on gc_complete_cond_; 2103 gc_complete_cond_->Wait(self); 2104 last_gc_type = last_gc_type_; 2105 ATRACE_END(); 2106 } 2107 uint64_t wait_time = NanoTime() - wait_start; 2108 total_wait_time_ += wait_time; 2109 if (wait_time > long_pause_log_threshold_) { 2110 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2111 } 2112 return last_gc_type; 2113} 2114 2115void Heap::DumpForSigQuit(std::ostream& os) { 2116 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2117 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2118 DumpGcPerformanceInfo(os); 2119} 2120 2121size_t Heap::GetPercentFree() { 2122 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2123} 2124 2125void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2126 if (max_allowed_footprint > GetMaxMemory()) { 2127 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2128 << PrettySize(GetMaxMemory()); 2129 max_allowed_footprint = GetMaxMemory(); 2130 } 2131 max_allowed_footprint_ = max_allowed_footprint; 2132} 2133 2134bool Heap::IsMovableObject(const mirror::Object* obj) const { 2135 if (kMovingCollector) { 2136 DCHECK(!IsInTempSpace(obj)); 2137 if (bump_pointer_space_->HasAddress(obj)) { 2138 return true; 2139 } 2140 // TODO: Refactor this logic into the space itself? 2141 // Objects in the main space are only copied during background -> foreground transitions or 2142 // visa versa. 2143 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2144 (IsCompactingGC(background_collector_type_) || 2145 IsCompactingGC(post_zygote_collector_type_))) { 2146 return true; 2147 } 2148 } 2149 return false; 2150} 2151 2152bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2153 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2154 return true; 2155 } 2156 return false; 2157} 2158 2159void Heap::UpdateMaxNativeFootprint() { 2160 size_t native_size = native_bytes_allocated_; 2161 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2162 size_t target_size = native_size / GetTargetHeapUtilization(); 2163 if (target_size > native_size + max_free_) { 2164 target_size = native_size + max_free_; 2165 } else if (target_size < native_size + min_free_) { 2166 target_size = native_size + min_free_; 2167 } 2168 native_footprint_gc_watermark_ = target_size; 2169 native_footprint_limit_ = 2 * target_size - native_size; 2170} 2171 2172void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2173 // We know what our utilization is at this moment. 2174 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2175 const size_t bytes_allocated = GetBytesAllocated(); 2176 last_gc_size_ = bytes_allocated; 2177 last_gc_time_ns_ = NanoTime(); 2178 size_t target_size; 2179 if (gc_type != collector::kGcTypeSticky) { 2180 // Grow the heap for non sticky GC. 2181 target_size = bytes_allocated / GetTargetHeapUtilization(); 2182 if (target_size > bytes_allocated + max_free_) { 2183 target_size = bytes_allocated + max_free_; 2184 } else if (target_size < bytes_allocated + min_free_) { 2185 target_size = bytes_allocated + min_free_; 2186 } 2187 native_need_to_run_finalization_ = true; 2188 next_gc_type_ = collector::kGcTypeSticky; 2189 } else { 2190 // Based on how close the current heap size is to the target size, decide 2191 // whether or not to do a partial or sticky GC next. 2192 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2193 next_gc_type_ = collector::kGcTypeSticky; 2194 } else { 2195 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2196 } 2197 // If we have freed enough memory, shrink the heap back down. 2198 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2199 target_size = bytes_allocated + max_free_; 2200 } else { 2201 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2202 } 2203 } 2204 if (!ignore_max_footprint_) { 2205 SetIdealFootprint(target_size); 2206 if (concurrent_gc_) { 2207 // Calculate when to perform the next ConcurrentGC. 2208 // Calculate the estimated GC duration. 2209 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2210 // Estimate how many remaining bytes we will have when we need to start the next GC. 2211 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2212 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2213 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2214 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2215 // A never going to happen situation that from the estimated allocation rate we will exceed 2216 // the applications entire footprint with the given estimated allocation rate. Schedule 2217 // another GC nearly straight away. 2218 remaining_bytes = kMinConcurrentRemainingBytes; 2219 } 2220 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2221 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2222 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2223 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2224 // right away. 2225 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2226 } 2227 } 2228} 2229 2230void Heap::ClearGrowthLimit() { 2231 growth_limit_ = capacity_; 2232 non_moving_space_->ClearGrowthLimit(); 2233} 2234 2235void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2236 MemberOffset reference_queue_offset, 2237 MemberOffset reference_queueNext_offset, 2238 MemberOffset reference_pendingNext_offset, 2239 MemberOffset finalizer_reference_zombie_offset) { 2240 reference_referent_offset_ = reference_referent_offset; 2241 reference_queue_offset_ = reference_queue_offset; 2242 reference_queueNext_offset_ = reference_queueNext_offset; 2243 reference_pendingNext_offset_ = reference_pendingNext_offset; 2244 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2245 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2246 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2247 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2248 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2249 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2250} 2251 2252void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2253 DCHECK(reference != NULL); 2254 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2255 reference->SetFieldObject(reference_referent_offset_, referent, true); 2256} 2257 2258mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2259 DCHECK(reference != NULL); 2260 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2261 return reference->GetFieldObject<mirror::Object*>(reference_referent_offset_, true); 2262} 2263 2264void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2265 ScopedObjectAccess soa(self); 2266 JValue result; 2267 ArgArray arg_array(NULL, 0); 2268 arg_array.Append(reinterpret_cast<uint32_t>(object)); 2269 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2270 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2271} 2272 2273void Heap::EnqueueClearedReferences() { 2274 if (!cleared_references_.IsEmpty()) { 2275 // When a runtime isn't started there are no reference queues to care about so ignore. 2276 if (LIKELY(Runtime::Current()->IsStarted())) { 2277 ScopedObjectAccess soa(Thread::Current()); 2278 JValue result; 2279 ArgArray arg_array(NULL, 0); 2280 arg_array.Append(reinterpret_cast<uint32_t>(cleared_references_.GetList())); 2281 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2282 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2283 } 2284 cleared_references_.Clear(); 2285 } 2286} 2287 2288void Heap::RequestConcurrentGC(Thread* self) { 2289 // Make sure that we can do a concurrent GC. 2290 Runtime* runtime = Runtime::Current(); 2291 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2292 self->IsHandlingStackOverflow()) { 2293 return; 2294 } 2295 // We already have a request pending, no reason to start more until we update 2296 // concurrent_start_bytes_. 2297 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2298 JNIEnv* env = self->GetJniEnv(); 2299 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2300 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2301 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2302 WellKnownClasses::java_lang_Daemons_requestGC); 2303 CHECK(!env->ExceptionCheck()); 2304} 2305 2306void Heap::ConcurrentGC(Thread* self) { 2307 if (Runtime::Current()->IsShuttingDown(self)) { 2308 return; 2309 } 2310 // Wait for any GCs currently running to finish. 2311 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2312 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2313 // instead. E.g. can't do partial, so do full instead. 2314 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2315 collector::kGcTypeNone) { 2316 for (collector::GcType gc_type : gc_plan_) { 2317 // Attempt to run the collector, if we succeed, we are done. 2318 if (gc_type > next_gc_type_ && 2319 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2320 break; 2321 } 2322 } 2323 } 2324 } 2325} 2326 2327void Heap::RequestHeapTrim() { 2328 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2329 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2330 // a space it will hold its lock and can become a cause of jank. 2331 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2332 // forking. 2333 2334 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2335 // because that only marks object heads, so a large array looks like lots of empty space. We 2336 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2337 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2338 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2339 // not how much use we're making of those pages. 2340 uint64_t ms_time = MilliTime(); 2341 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2342 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2343 return; 2344 } 2345 2346 Thread* self = Thread::Current(); 2347 Runtime* runtime = Runtime::Current(); 2348 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2349 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2350 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2351 // as we don't hold the lock while requesting the trim). 2352 return; 2353 } 2354 2355 last_trim_time_ms_ = ms_time; 2356 2357 // Trim only if we do not currently care about pause times. 2358 if (!CareAboutPauseTimes()) { 2359 JNIEnv* env = self->GetJniEnv(); 2360 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2361 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2362 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2363 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2364 CHECK(!env->ExceptionCheck()); 2365 } 2366} 2367 2368void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2369 if (rosalloc_space_ != nullptr) { 2370 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2371 } 2372 if (bump_pointer_space_ != nullptr) { 2373 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2374 } 2375} 2376 2377void Heap::RevokeAllThreadLocalBuffers() { 2378 if (rosalloc_space_ != nullptr) { 2379 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2380 } 2381 if (bump_pointer_space_ != nullptr) { 2382 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2383 } 2384} 2385 2386bool Heap::IsGCRequestPending() const { 2387 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2388} 2389 2390void Heap::RunFinalization(JNIEnv* env) { 2391 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2392 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2393 CHECK(WellKnownClasses::java_lang_System != nullptr); 2394 WellKnownClasses::java_lang_System_runFinalization = 2395 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2396 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2397 } 2398 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2399 WellKnownClasses::java_lang_System_runFinalization); 2400} 2401 2402void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2403 Thread* self = ThreadForEnv(env); 2404 if (native_need_to_run_finalization_) { 2405 RunFinalization(env); 2406 UpdateMaxNativeFootprint(); 2407 native_need_to_run_finalization_ = false; 2408 } 2409 // Total number of native bytes allocated. 2410 native_bytes_allocated_.FetchAndAdd(bytes); 2411 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2412 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2413 collector::kGcTypeFull; 2414 2415 // The second watermark is higher than the gc watermark. If you hit this it means you are 2416 // allocating native objects faster than the GC can keep up with. 2417 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2418 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2419 // Just finished a GC, attempt to run finalizers. 2420 RunFinalization(env); 2421 CHECK(!env->ExceptionCheck()); 2422 } 2423 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2424 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2425 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2426 RunFinalization(env); 2427 native_need_to_run_finalization_ = false; 2428 CHECK(!env->ExceptionCheck()); 2429 } 2430 // We have just run finalizers, update the native watermark since it is very likely that 2431 // finalizers released native managed allocations. 2432 UpdateMaxNativeFootprint(); 2433 } else if (!IsGCRequestPending()) { 2434 if (concurrent_gc_) { 2435 RequestConcurrentGC(self); 2436 } else { 2437 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2438 } 2439 } 2440 } 2441} 2442 2443void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2444 int expected_size, new_size; 2445 do { 2446 expected_size = native_bytes_allocated_.Load(); 2447 new_size = expected_size - bytes; 2448 if (UNLIKELY(new_size < 0)) { 2449 ScopedObjectAccess soa(env); 2450 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2451 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2452 "registered as allocated", bytes, expected_size).c_str()); 2453 break; 2454 } 2455 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2456} 2457 2458int64_t Heap::GetTotalMemory() const { 2459 int64_t ret = 0; 2460 for (const auto& space : continuous_spaces_) { 2461 // Currently don't include the image space. 2462 if (!space->IsImageSpace()) { 2463 ret += space->Size(); 2464 } 2465 } 2466 for (const auto& space : discontinuous_spaces_) { 2467 if (space->IsLargeObjectSpace()) { 2468 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2469 } 2470 } 2471 return ret; 2472} 2473 2474void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2475 DCHECK(mod_union_table != nullptr); 2476 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2477} 2478 2479} // namespace gc 2480} // namespace art 2481