heap.cc revision a4adbfd44032d70e166e6f18096bbbed05a990ba
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <vector> 24#include <valgrind.h> 25 26#include "base/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/mark_sweep-inl.h" 38#include "gc/collector/partial_mark_sweep.h" 39#include "gc/collector/semi_space.h" 40#include "gc/collector/sticky_mark_sweep.h" 41#include "gc/space/bump_pointer_space.h" 42#include "gc/space/dlmalloc_space-inl.h" 43#include "gc/space/image_space.h" 44#include "gc/space/large_object_space.h" 45#include "gc/space/rosalloc_space-inl.h" 46#include "gc/space/space-inl.h" 47#include "gc/space/zygote_space.h" 48#include "heap-inl.h" 49#include "image.h" 50#include "invoke_arg_array_builder.h" 51#include "mirror/art_field-inl.h" 52#include "mirror/class-inl.h" 53#include "mirror/object.h" 54#include "mirror/object-inl.h" 55#include "mirror/object_array-inl.h" 56#include "object_utils.h" 57#include "os.h" 58#include "runtime.h" 59#include "ScopedLocalRef.h" 60#include "scoped_thread_state_change.h" 61#include "sirt_ref.h" 62#include "thread_list.h" 63#include "UniquePtr.h" 64#include "well_known_classes.h" 65 66namespace art { 67 68extern void SetQuickAllocEntryPointsAllocator(gc::AllocatorType allocator); 69 70namespace gc { 71 72static constexpr bool kGCALotMode = false; 73static constexpr size_t kGcAlotInterval = KB; 74// Minimum amount of remaining bytes before a concurrent GC is triggered. 75static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 76static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 77 78Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 79 double target_utilization, size_t capacity, const std::string& image_file_name, 80 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 81 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 82 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 83 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 84 bool verify_post_gc_heap, bool verify_pre_gc_rosalloc, 85 bool verify_post_gc_rosalloc) 86 : non_moving_space_(nullptr), 87 rosalloc_space_(nullptr), 88 dlmalloc_space_(nullptr), 89 main_space_(nullptr), 90 concurrent_gc_(false), 91 collector_type_(kCollectorTypeNone), 92 post_zygote_collector_type_(post_zygote_collector_type), 93 background_collector_type_(background_collector_type), 94 parallel_gc_threads_(parallel_gc_threads), 95 conc_gc_threads_(conc_gc_threads), 96 low_memory_mode_(low_memory_mode), 97 long_pause_log_threshold_(long_pause_log_threshold), 98 long_gc_log_threshold_(long_gc_log_threshold), 99 ignore_max_footprint_(ignore_max_footprint), 100 have_zygote_space_(false), 101 soft_reference_queue_(this), 102 weak_reference_queue_(this), 103 finalizer_reference_queue_(this), 104 phantom_reference_queue_(this), 105 cleared_references_(this), 106 collector_type_running_(kCollectorTypeNone), 107 last_gc_type_(collector::kGcTypeNone), 108 next_gc_type_(collector::kGcTypePartial), 109 capacity_(capacity), 110 growth_limit_(growth_limit), 111 max_allowed_footprint_(initial_size), 112 native_footprint_gc_watermark_(initial_size), 113 native_footprint_limit_(2 * initial_size), 114 native_need_to_run_finalization_(false), 115 // Initially assume we perceive jank in case the process state is never updated. 116 process_state_(kProcessStateJankPerceptible), 117 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 118 total_bytes_freed_ever_(0), 119 total_objects_freed_ever_(0), 120 num_bytes_allocated_(0), 121 native_bytes_allocated_(0), 122 gc_memory_overhead_(0), 123 verify_missing_card_marks_(false), 124 verify_system_weaks_(false), 125 verify_pre_gc_heap_(verify_pre_gc_heap), 126 verify_post_gc_heap_(verify_post_gc_heap), 127 verify_mod_union_table_(false), 128 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 129 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 130 last_trim_time_ms_(0), 131 allocation_rate_(0), 132 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 133 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 134 * verification is enabled, we limit the size of allocation stacks to speed up their 135 * searching. 136 */ 137 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 138 : (kDesiredHeapVerification > kVerifyAllFast) ? KB : MB), 139 current_allocator_(kAllocatorTypeDlMalloc), 140 current_non_moving_allocator_(kAllocatorTypeNonMoving), 141 bump_pointer_space_(nullptr), 142 temp_space_(nullptr), 143 reference_referent_offset_(0), 144 reference_queue_offset_(0), 145 reference_queueNext_offset_(0), 146 reference_pendingNext_offset_(0), 147 finalizer_reference_zombie_offset_(0), 148 min_free_(min_free), 149 max_free_(max_free), 150 target_utilization_(target_utilization), 151 total_wait_time_(0), 152 total_allocation_time_(0), 153 verify_object_mode_(kHeapVerificationNotPermitted), 154 disable_moving_gc_count_(0), 155 running_on_valgrind_(RUNNING_ON_VALGRIND), 156 use_tlab_(use_tlab) { 157 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 158 LOG(INFO) << "Heap() entering"; 159 } 160 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 161 // entrypoints. 162 if (!Runtime::Current()->IsZygote() || !kMovingCollector) { 163 ChangeCollector(post_zygote_collector_type_); 164 } else { 165 // We are the zygote, use bump pointer allocation + semi space collector. 166 ChangeCollector(kCollectorTypeSS); 167 } 168 169 live_bitmap_.reset(new accounting::HeapBitmap(this)); 170 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 171 // Requested begin for the alloc space, to follow the mapped image and oat files 172 byte* requested_alloc_space_begin = nullptr; 173 if (!image_file_name.empty()) { 174 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 175 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 176 AddSpace(image_space); 177 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 178 // isn't going to get in the middle 179 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 180 CHECK_GT(oat_file_end_addr, image_space->End()); 181 if (oat_file_end_addr > requested_alloc_space_begin) { 182 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 183 } 184 } 185 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 186 space::MallocSpace* malloc_space; 187 if (kUseRosAlloc) { 188 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 189 requested_alloc_space_begin, low_memory_mode_); 190 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 191 } else { 192 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 193 requested_alloc_space_begin); 194 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 195 } 196 VLOG(heap) << "malloc_space : " << malloc_space; 197 if (kMovingCollector) { 198 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 199 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 200 // issues. 201 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 202 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 203 bump_pointer_space_size, nullptr); 204 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 205 AddSpace(bump_pointer_space_); 206 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 207 nullptr); 208 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 209 AddSpace(temp_space_); 210 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 211 VLOG(heap) << "temp_space : " << temp_space_; 212 } 213 non_moving_space_ = malloc_space; 214 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 215 AddSpace(malloc_space); 216 217 // Allocate the large object space. 218 constexpr bool kUseFreeListSpaceForLOS = false; 219 if (kUseFreeListSpaceForLOS) { 220 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 221 } else { 222 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 223 } 224 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 225 AddSpace(large_object_space_); 226 227 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 228 CHECK(!continuous_spaces_.empty()); 229 230 // Relies on the spaces being sorted. 231 byte* heap_begin = continuous_spaces_.front()->Begin(); 232 byte* heap_end = continuous_spaces_.back()->Limit(); 233 if (Runtime::Current()->IsZygote()) { 234 std::string error_str; 235 post_zygote_non_moving_space_mem_map_.reset( 236 MemMap::MapAnonymous("post zygote non-moving space", nullptr, 64 * MB, 237 PROT_READ | PROT_WRITE, true, &error_str)); 238 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 239 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 240 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 241 } 242 size_t heap_capacity = heap_end - heap_begin; 243 244 // Allocate the card table. 245 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 246 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 247 248 // Card cache for now since it makes it easier for us to update the references to the copying 249 // spaces. 250 accounting::ModUnionTable* mod_union_table = 251 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 252 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 253 AddModUnionTable(mod_union_table); 254 255 // TODO: Count objects in the image space here. 256 num_bytes_allocated_ = 0; 257 258 // Default mark stack size in bytes. 259 static const size_t default_mark_stack_size = 64 * KB; 260 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 261 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 262 max_allocation_stack_size_)); 263 live_stack_.reset(accounting::ObjectStack::Create("live stack", 264 max_allocation_stack_size_)); 265 266 // It's still too early to take a lock because there are no threads yet, but we can create locks 267 // now. We don't create it earlier to make it clear that you can't use locks during heap 268 // initialization. 269 gc_complete_lock_ = new Mutex("GC complete lock"); 270 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 271 *gc_complete_lock_)); 272 last_gc_time_ns_ = NanoTime(); 273 last_gc_size_ = GetBytesAllocated(); 274 275 if (ignore_max_footprint_) { 276 SetIdealFootprint(std::numeric_limits<size_t>::max()); 277 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 278 } 279 CHECK_NE(max_allowed_footprint_, 0U); 280 281 // Create our garbage collectors. 282 for (size_t i = 0; i < 2; ++i) { 283 const bool concurrent = i != 0; 284 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 285 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 286 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 287 } 288 if (kMovingCollector) { 289 // TODO: Clean this up. 290 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 291 semi_space_collector_ = new collector::SemiSpace(this, generational); 292 garbage_collectors_.push_back(semi_space_collector_); 293 } 294 295 if (running_on_valgrind_) { 296 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 297 } 298 299 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 300 LOG(INFO) << "Heap() exiting"; 301 } 302} 303 304void Heap::ChangeAllocator(AllocatorType allocator) { 305 // These two allocators are only used internally and don't have any entrypoints. 306 DCHECK_NE(allocator, kAllocatorTypeLOS); 307 DCHECK_NE(allocator, kAllocatorTypeNonMoving); 308 if (current_allocator_ != allocator) { 309 current_allocator_ = allocator; 310 SetQuickAllocEntryPointsAllocator(current_allocator_); 311 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 312 } 313} 314 315bool Heap::IsCompilingBoot() const { 316 for (const auto& space : continuous_spaces_) { 317 if (space->IsImageSpace()) { 318 return false; 319 } else if (space->IsZygoteSpace()) { 320 return false; 321 } 322 } 323 return true; 324} 325 326bool Heap::HasImageSpace() const { 327 for (const auto& space : continuous_spaces_) { 328 if (space->IsImageSpace()) { 329 return true; 330 } 331 } 332 return false; 333} 334 335void Heap::IncrementDisableMovingGC(Thread* self) { 336 // Need to do this holding the lock to prevent races where the GC is about to run / running when 337 // we attempt to disable it. 338 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 339 MutexLock mu(self, *gc_complete_lock_); 340 ++disable_moving_gc_count_; 341 if (IsCompactingGC(collector_type_running_)) { 342 WaitForGcToCompleteLocked(self); 343 } 344} 345 346void Heap::DecrementDisableMovingGC(Thread* self) { 347 MutexLock mu(self, *gc_complete_lock_); 348 CHECK_GE(disable_moving_gc_count_, 0U); 349 --disable_moving_gc_count_; 350} 351 352void Heap::UpdateProcessState(ProcessState process_state) { 353 if (process_state_ != process_state) { 354 process_state_ = process_state; 355 if (process_state_ == kProcessStateJankPerceptible) { 356 TransitionCollector(post_zygote_collector_type_); 357 } else { 358 TransitionCollector(background_collector_type_); 359 } 360 } else { 361 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 362 } 363} 364 365void Heap::CreateThreadPool() { 366 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 367 if (num_threads != 0) { 368 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 369 } 370} 371 372void Heap::VisitObjects(ObjectVisitorCallback callback, void* arg) { 373 Thread* self = Thread::Current(); 374 // GCs can move objects, so don't allow this. 375 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 376 if (bump_pointer_space_ != nullptr) { 377 // Visit objects in bump pointer space. 378 bump_pointer_space_->Walk(callback, arg); 379 } 380 // TODO: Switch to standard begin and end to use ranged a based loop. 381 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 382 it < end; ++it) { 383 mirror::Object* obj = *it; 384 callback(obj, arg); 385 } 386 GetLiveBitmap()->Walk(callback, arg); 387 self->EndAssertNoThreadSuspension(old_cause); 388} 389 390void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 391 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 392 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 393 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 394 // TODO: Generalize this to n bitmaps? 395 if (space1 == nullptr) { 396 DCHECK(space2 != nullptr); 397 space1 = space2; 398 } 399 if (space2 == nullptr) { 400 DCHECK(space1 != nullptr); 401 space2 = space1; 402 } 403 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 404 large_object_space_->GetLiveObjects(), stack); 405} 406 407void Heap::DeleteThreadPool() { 408 thread_pool_.reset(nullptr); 409} 410 411void Heap::AddSpace(space::Space* space, bool set_as_default) { 412 DCHECK(space != nullptr); 413 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 414 if (space->IsContinuousSpace()) { 415 DCHECK(!space->IsDiscontinuousSpace()); 416 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 417 // Continuous spaces don't necessarily have bitmaps. 418 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 419 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 420 if (live_bitmap != nullptr) { 421 DCHECK(mark_bitmap != nullptr); 422 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 423 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 424 } 425 continuous_spaces_.push_back(continuous_space); 426 if (set_as_default) { 427 if (continuous_space->IsDlMallocSpace()) { 428 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 429 } else if (continuous_space->IsRosAllocSpace()) { 430 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 431 } 432 } 433 // Ensure that spaces remain sorted in increasing order of start address. 434 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 435 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 436 return a->Begin() < b->Begin(); 437 }); 438 } else { 439 DCHECK(space->IsDiscontinuousSpace()); 440 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 441 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 442 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 443 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 444 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 445 discontinuous_spaces_.push_back(discontinuous_space); 446 } 447 if (space->IsAllocSpace()) { 448 alloc_spaces_.push_back(space->AsAllocSpace()); 449 } 450} 451 452void Heap::RemoveSpace(space::Space* space) { 453 DCHECK(space != nullptr); 454 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 455 if (space->IsContinuousSpace()) { 456 DCHECK(!space->IsDiscontinuousSpace()); 457 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 458 // Continuous spaces don't necessarily have bitmaps. 459 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 460 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 461 if (live_bitmap != nullptr) { 462 DCHECK(mark_bitmap != nullptr); 463 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 464 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 465 } 466 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 467 DCHECK(it != continuous_spaces_.end()); 468 continuous_spaces_.erase(it); 469 if (continuous_space == dlmalloc_space_) { 470 dlmalloc_space_ = nullptr; 471 } else if (continuous_space == rosalloc_space_) { 472 rosalloc_space_ = nullptr; 473 } 474 if (continuous_space == main_space_) { 475 main_space_ = nullptr; 476 } 477 } else { 478 DCHECK(space->IsDiscontinuousSpace()); 479 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 480 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 481 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 482 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 483 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 484 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 485 discontinuous_space); 486 DCHECK(it != discontinuous_spaces_.end()); 487 discontinuous_spaces_.erase(it); 488 } 489 if (space->IsAllocSpace()) { 490 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 491 DCHECK(it != alloc_spaces_.end()); 492 alloc_spaces_.erase(it); 493 } 494} 495 496void Heap::RegisterGCAllocation(size_t bytes) { 497 if (this != nullptr) { 498 gc_memory_overhead_.FetchAndAdd(bytes); 499 } 500} 501 502void Heap::RegisterGCDeAllocation(size_t bytes) { 503 if (this != nullptr) { 504 gc_memory_overhead_.FetchAndSub(bytes); 505 } 506} 507 508void Heap::DumpGcPerformanceInfo(std::ostream& os) { 509 // Dump cumulative timings. 510 os << "Dumping cumulative Gc timings\n"; 511 uint64_t total_duration = 0; 512 513 // Dump cumulative loggers for each GC type. 514 uint64_t total_paused_time = 0; 515 for (const auto& collector : garbage_collectors_) { 516 CumulativeLogger& logger = collector->GetCumulativeTimings(); 517 if (logger.GetTotalNs() != 0) { 518 os << Dumpable<CumulativeLogger>(logger); 519 const uint64_t total_ns = logger.GetTotalNs(); 520 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 521 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 522 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 523 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 524 Histogram<uint64_t>::CumulativeData cumulative_data; 525 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 526 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 527 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 528 << collector->GetName() << " freed: " << freed_objects 529 << " objects with total size " << PrettySize(freed_bytes) << "\n" 530 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 531 << PrettySize(freed_bytes / seconds) << "/s\n"; 532 total_duration += total_ns; 533 total_paused_time += total_pause_ns; 534 } 535 } 536 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 537 if (total_duration != 0) { 538 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 539 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 540 os << "Mean GC size throughput: " 541 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 542 os << "Mean GC object throughput: " 543 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 544 } 545 size_t total_objects_allocated = GetObjectsAllocatedEver(); 546 os << "Total number of allocations: " << total_objects_allocated << "\n"; 547 size_t total_bytes_allocated = GetBytesAllocatedEver(); 548 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 549 if (kMeasureAllocationTime) { 550 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 551 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 552 << "\n"; 553 } 554 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 555 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 556 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 557} 558 559Heap::~Heap() { 560 VLOG(heap) << "Starting ~Heap()"; 561 STLDeleteElements(&garbage_collectors_); 562 // If we don't reset then the mark stack complains in its destructor. 563 allocation_stack_->Reset(); 564 live_stack_->Reset(); 565 STLDeleteValues(&mod_union_tables_); 566 STLDeleteElements(&continuous_spaces_); 567 STLDeleteElements(&discontinuous_spaces_); 568 delete gc_complete_lock_; 569 VLOG(heap) << "Finished ~Heap()"; 570} 571 572space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 573 bool fail_ok) const { 574 for (const auto& space : continuous_spaces_) { 575 if (space->Contains(obj)) { 576 return space; 577 } 578 } 579 if (!fail_ok) { 580 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 581 } 582 return NULL; 583} 584 585space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 586 bool fail_ok) const { 587 for (const auto& space : discontinuous_spaces_) { 588 if (space->Contains(obj)) { 589 return space; 590 } 591 } 592 if (!fail_ok) { 593 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 594 } 595 return NULL; 596} 597 598space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 599 space::Space* result = FindContinuousSpaceFromObject(obj, true); 600 if (result != NULL) { 601 return result; 602 } 603 return FindDiscontinuousSpaceFromObject(obj, true); 604} 605 606struct SoftReferenceArgs { 607 RootVisitor* is_marked_callback_; 608 RootVisitor* recursive_mark_callback_; 609 void* arg_; 610}; 611 612mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 613 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 614 // TODO: Not preserve all soft references. 615 return args->recursive_mark_callback_(obj, args->arg_); 616} 617 618// Process reference class instances and schedule finalizations. 619void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 620 RootVisitor* is_marked_callback, 621 RootVisitor* recursive_mark_object_callback, void* arg) { 622 // Unless we are in the zygote or required to clear soft references with white references, 623 // preserve some white referents. 624 if (!clear_soft && !Runtime::Current()->IsZygote()) { 625 SoftReferenceArgs soft_reference_args; 626 soft_reference_args.is_marked_callback_ = is_marked_callback; 627 soft_reference_args.recursive_mark_callback_ = recursive_mark_object_callback; 628 soft_reference_args.arg_ = arg; 629 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 630 &soft_reference_args); 631 } 632 timings.StartSplit("ProcessReferences"); 633 // Clear all remaining soft and weak references with white referents. 634 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 635 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 636 timings.EndSplit(); 637 // Preserve all white objects with finalize methods and schedule them for finalization. 638 timings.StartSplit("EnqueueFinalizerReferences"); 639 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 640 recursive_mark_object_callback, arg); 641 timings.EndSplit(); 642 timings.StartSplit("ProcessReferences"); 643 // Clear all f-reachable soft and weak references with white referents. 644 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 645 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 646 // Clear all phantom references with white referents. 647 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 648 // At this point all reference queues other than the cleared references should be empty. 649 DCHECK(soft_reference_queue_.IsEmpty()); 650 DCHECK(weak_reference_queue_.IsEmpty()); 651 DCHECK(finalizer_reference_queue_.IsEmpty()); 652 DCHECK(phantom_reference_queue_.IsEmpty()); 653 timings.EndSplit(); 654} 655 656bool Heap::IsEnqueued(mirror::Object* ref) const { 657 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 658 // will always be non-null. 659 return ref->GetFieldObject<mirror::Object>(GetReferencePendingNextOffset(), false) != nullptr; 660} 661 662bool Heap::IsEnqueuable(mirror::Object* ref) const { 663 DCHECK(ref != nullptr); 664 const mirror::Object* queue = 665 ref->GetFieldObject<mirror::Object>(GetReferenceQueueOffset(), false); 666 const mirror::Object* queue_next = 667 ref->GetFieldObject<mirror::Object>(GetReferenceQueueNextOffset(), false); 668 return queue != nullptr && queue_next == nullptr; 669} 670 671// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 672// marked, put it on the appropriate list in the heap for later processing. 673void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 674 RootVisitor mark_visitor, void* arg) { 675 DCHECK(klass != nullptr); 676 DCHECK(klass->IsReferenceClass()); 677 DCHECK(obj != nullptr); 678 mirror::Object* referent = GetReferenceReferent(obj); 679 if (referent != nullptr) { 680 mirror::Object* forward_address = mark_visitor(referent, arg); 681 // Null means that the object is not currently marked. 682 if (forward_address == nullptr) { 683 Thread* self = Thread::Current(); 684 // TODO: Remove these locks, and use atomic stacks for storing references? 685 // We need to check that the references haven't already been enqueued since we can end up 686 // scanning the same reference multiple times due to dirty cards. 687 if (klass->IsSoftReferenceClass()) { 688 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 689 } else if (klass->IsWeakReferenceClass()) { 690 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 691 } else if (klass->IsFinalizerReferenceClass()) { 692 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 693 } else if (klass->IsPhantomReferenceClass()) { 694 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 695 } else { 696 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 697 << klass->GetAccessFlags(); 698 } 699 } else if (referent != forward_address) { 700 // Referent is already marked and we need to update it. 701 SetReferenceReferent(obj, forward_address); 702 } 703 } 704} 705 706space::ImageSpace* Heap::GetImageSpace() const { 707 for (const auto& space : continuous_spaces_) { 708 if (space->IsImageSpace()) { 709 return space->AsImageSpace(); 710 } 711 } 712 return NULL; 713} 714 715static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 716 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 717 if (used_bytes < chunk_size) { 718 size_t chunk_free_bytes = chunk_size - used_bytes; 719 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 720 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 721 } 722} 723 724void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 725 std::ostringstream oss; 726 size_t total_bytes_free = GetFreeMemory(); 727 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 728 << " free bytes"; 729 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 730 if (!large_object_allocation && total_bytes_free >= byte_count) { 731 size_t max_contiguous_allocation = 0; 732 for (const auto& space : continuous_spaces_) { 733 if (space->IsMallocSpace()) { 734 // To allow the Walk/InspectAll() to exclusively-lock the mutator 735 // lock, temporarily release the shared access to the mutator 736 // lock here by transitioning to the suspended state. 737 Locks::mutator_lock_->AssertSharedHeld(self); 738 self->TransitionFromRunnableToSuspended(kSuspended); 739 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 740 self->TransitionFromSuspendedToRunnable(); 741 Locks::mutator_lock_->AssertSharedHeld(self); 742 } 743 } 744 oss << "; failed due to fragmentation (largest possible contiguous allocation " 745 << max_contiguous_allocation << " bytes)"; 746 } 747 self->ThrowOutOfMemoryError(oss.str().c_str()); 748} 749 750void Heap::Trim() { 751 Thread* self = Thread::Current(); 752 { 753 // Need to do this before acquiring the locks since we don't want to get suspended while 754 // holding any locks. 755 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 756 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 757 // trimming. 758 MutexLock mu(self, *gc_complete_lock_); 759 // Ensure there is only one GC at a time. 760 WaitForGcToCompleteLocked(self); 761 collector_type_running_ = kCollectorTypeHeapTrim; 762 } 763 uint64_t start_ns = NanoTime(); 764 // Trim the managed spaces. 765 uint64_t total_alloc_space_allocated = 0; 766 uint64_t total_alloc_space_size = 0; 767 uint64_t managed_reclaimed = 0; 768 for (const auto& space : continuous_spaces_) { 769 if (space->IsMallocSpace()) { 770 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 771 total_alloc_space_size += alloc_space->Size(); 772 managed_reclaimed += alloc_space->Trim(); 773 } 774 } 775 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 776 bump_pointer_space_->Size(); 777 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 778 static_cast<float>(total_alloc_space_size); 779 uint64_t gc_heap_end_ns = NanoTime(); 780 // We never move things in the native heap, so we can finish the GC at this point. 781 FinishGC(self, collector::kGcTypeNone); 782 // Trim the native heap. 783 dlmalloc_trim(0); 784 size_t native_reclaimed = 0; 785 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 786 uint64_t end_ns = NanoTime(); 787 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 788 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 789 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 790 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 791 << "%."; 792} 793 794bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 795 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 796 // taking the lock. 797 if (obj == nullptr) { 798 return true; 799 } 800 return IsAligned<kObjectAlignment>(obj) && IsHeapAddress(obj); 801} 802 803bool Heap::IsHeapAddress(const mirror::Object* obj) const { 804 if (kMovingCollector && bump_pointer_space_ && bump_pointer_space_->HasAddress(obj)) { 805 return true; 806 } 807 // TODO: This probably doesn't work for large objects. 808 return FindSpaceFromObject(obj, true) != nullptr; 809} 810 811bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 812 bool search_live_stack, bool sorted) { 813 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 814 return false; 815 } 816 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 817 mirror::Class* klass = obj->GetClass(); 818 if (obj == klass) { 819 // This case happens for java.lang.Class. 820 return true; 821 } 822 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 823 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 824 return false; 825 } 826 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 827 space::DiscontinuousSpace* d_space = NULL; 828 if (c_space != nullptr) { 829 if (c_space->GetLiveBitmap()->Test(obj)) { 830 return true; 831 } 832 } else { 833 d_space = FindDiscontinuousSpaceFromObject(obj, true); 834 if (d_space != nullptr) { 835 if (d_space->GetLiveObjects()->Test(obj)) { 836 return true; 837 } 838 } 839 } 840 // This is covering the allocation/live stack swapping that is done without mutators suspended. 841 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 842 if (i > 0) { 843 NanoSleep(MsToNs(10)); 844 } 845 if (search_allocation_stack) { 846 if (sorted) { 847 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 848 return true; 849 } 850 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 851 return true; 852 } 853 } 854 855 if (search_live_stack) { 856 if (sorted) { 857 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 858 return true; 859 } 860 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 861 return true; 862 } 863 } 864 } 865 // We need to check the bitmaps again since there is a race where we mark something as live and 866 // then clear the stack containing it. 867 if (c_space != nullptr) { 868 if (c_space->GetLiveBitmap()->Test(obj)) { 869 return true; 870 } 871 } else { 872 d_space = FindDiscontinuousSpaceFromObject(obj, true); 873 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 874 return true; 875 } 876 } 877 return false; 878} 879 880void Heap::VerifyObjectImpl(mirror::Object* obj) { 881 if (Thread::Current() == NULL || 882 Runtime::Current()->GetThreadList()->GetLockOwner() == Thread::Current()->GetTid()) { 883 return; 884 } 885 VerifyObjectBody(obj); 886} 887 888bool Heap::VerifyClassClass(const mirror::Class* c) const { 889 // Note: we don't use the accessors here as they have internal sanity checks that we don't want 890 // to run 891 const byte* raw_addr = 892 reinterpret_cast<const byte*>(c) + mirror::Object::ClassOffset().Int32Value(); 893 mirror::Class* c_c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 894 raw_addr = reinterpret_cast<const byte*>(c_c) + mirror::Object::ClassOffset().Int32Value(); 895 mirror::Class* c_c_c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 896 return c_c == c_c_c; 897} 898 899void Heap::DumpSpaces(std::ostream& stream) { 900 for (const auto& space : continuous_spaces_) { 901 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 902 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 903 stream << space << " " << *space << "\n"; 904 if (live_bitmap != nullptr) { 905 stream << live_bitmap << " " << *live_bitmap << "\n"; 906 } 907 if (mark_bitmap != nullptr) { 908 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 909 } 910 } 911 for (const auto& space : discontinuous_spaces_) { 912 stream << space << " " << *space << "\n"; 913 } 914} 915 916void Heap::VerifyObjectBody(mirror::Object* obj) { 917 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 918 // Ignore early dawn of the universe verifications. 919 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 920 return; 921 } 922 const byte* raw_addr = reinterpret_cast<const byte*>(obj) + 923 mirror::Object::ClassOffset().Int32Value(); 924 mirror::Class* c = reinterpret_cast<mirror::HeapReference<mirror::Class> const *>(raw_addr)->AsMirrorPtr(); 925 if (UNLIKELY(c == NULL)) { 926 LOG(FATAL) << "Null class in object: " << obj; 927 } else if (UNLIKELY(!IsAligned<kObjectAlignment>(c))) { 928 LOG(FATAL) << "Class isn't aligned: " << c << " in object: " << obj; 929 } 930 CHECK(VerifyClassClass(c)); 931 932 if (verify_object_mode_ > kVerifyAllFast) { 933 // TODO: the bitmap tests below are racy if VerifyObjectBody is called without the 934 // heap_bitmap_lock_. 935 if (!IsLiveObjectLocked(obj)) { 936 DumpSpaces(); 937 LOG(FATAL) << "Object is dead: " << obj; 938 } 939 if (!IsLiveObjectLocked(c)) { 940 LOG(FATAL) << "Class of object is dead: " << c << " in object: " << obj; 941 } 942 } 943} 944 945void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 946 DCHECK(obj != NULL); 947 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 948} 949 950void Heap::VerifyHeap() { 951 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 952 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 953} 954 955void Heap::RecordFree(size_t freed_objects, size_t freed_bytes) { 956 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 957 num_bytes_allocated_.FetchAndSub(freed_bytes); 958 if (Runtime::Current()->HasStatsEnabled()) { 959 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 960 thread_stats->freed_objects += freed_objects; 961 thread_stats->freed_bytes += freed_bytes; 962 // TODO: Do this concurrently. 963 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 964 global_stats->freed_objects += freed_objects; 965 global_stats->freed_bytes += freed_bytes; 966 } 967} 968 969mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 970 size_t alloc_size, size_t* bytes_allocated, 971 mirror::Class** klass) { 972 mirror::Object* ptr = nullptr; 973 bool was_default_allocator = allocator == GetCurrentAllocator(); 974 DCHECK(klass != nullptr); 975 SirtRef<mirror::Class> sirt_klass(self, *klass); 976 // The allocation failed. If the GC is running, block until it completes, and then retry the 977 // allocation. 978 collector::GcType last_gc = WaitForGcToComplete(self); 979 if (last_gc != collector::kGcTypeNone) { 980 // If we were the default allocator but the allocator changed while we were suspended, 981 // abort the allocation. 982 if (was_default_allocator && allocator != GetCurrentAllocator()) { 983 *klass = sirt_klass.get(); 984 return nullptr; 985 } 986 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 987 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 988 } 989 990 // Loop through our different Gc types and try to Gc until we get enough free memory. 991 for (collector::GcType gc_type : gc_plan_) { 992 if (ptr != nullptr) { 993 break; 994 } 995 // Attempt to run the collector, if we succeed, re-try the allocation. 996 bool gc_ran = 997 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 998 if (was_default_allocator && allocator != GetCurrentAllocator()) { 999 *klass = sirt_klass.get(); 1000 return nullptr; 1001 } 1002 if (gc_ran) { 1003 // Did we free sufficient memory for the allocation to succeed? 1004 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated); 1005 } 1006 } 1007 // Allocations have failed after GCs; this is an exceptional state. 1008 if (ptr == nullptr) { 1009 // Try harder, growing the heap if necessary. 1010 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1011 } 1012 if (ptr == nullptr) { 1013 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1014 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1015 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1016 // OOME. 1017 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1018 << " allocation"; 1019 // TODO: Run finalization, but this may cause more allocations to occur. 1020 // We don't need a WaitForGcToComplete here either. 1021 DCHECK(!gc_plan_.empty()); 1022 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1023 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1024 *klass = sirt_klass.get(); 1025 return nullptr; 1026 } 1027 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated); 1028 if (ptr == nullptr) { 1029 ThrowOutOfMemoryError(self, alloc_size, false); 1030 } 1031 } 1032 *klass = sirt_klass.get(); 1033 return ptr; 1034} 1035 1036void Heap::SetTargetHeapUtilization(float target) { 1037 DCHECK_GT(target, 0.0f); // asserted in Java code 1038 DCHECK_LT(target, 1.0f); 1039 target_utilization_ = target; 1040} 1041 1042size_t Heap::GetObjectsAllocated() const { 1043 size_t total = 0; 1044 for (space::AllocSpace* space : alloc_spaces_) { 1045 total += space->GetObjectsAllocated(); 1046 } 1047 return total; 1048} 1049 1050size_t Heap::GetObjectsAllocatedEver() const { 1051 return GetObjectsFreedEver() + GetObjectsAllocated(); 1052} 1053 1054size_t Heap::GetBytesAllocatedEver() const { 1055 return GetBytesFreedEver() + GetBytesAllocated(); 1056} 1057 1058class InstanceCounter { 1059 public: 1060 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1061 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1062 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1063 } 1064 1065 void operator()(mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1066 for (size_t i = 0; i < classes_.size(); ++i) { 1067 mirror::Class* instance_class = o->GetClass(); 1068 if (use_is_assignable_from_) { 1069 if (instance_class != NULL && classes_[i]->IsAssignableFrom(instance_class)) { 1070 ++counts_[i]; 1071 } 1072 } else { 1073 if (instance_class == classes_[i]) { 1074 ++counts_[i]; 1075 } 1076 } 1077 } 1078 } 1079 1080 private: 1081 const std::vector<mirror::Class*>& classes_; 1082 bool use_is_assignable_from_; 1083 uint64_t* const counts_; 1084 1085 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1086}; 1087 1088void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1089 uint64_t* counts) { 1090 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1091 // is empty, so the live bitmap is the only place we need to look. 1092 Thread* self = Thread::Current(); 1093 self->TransitionFromRunnableToSuspended(kNative); 1094 CollectGarbage(false); 1095 self->TransitionFromSuspendedToRunnable(); 1096 1097 InstanceCounter counter(classes, use_is_assignable_from, counts); 1098 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1099 GetLiveBitmap()->Visit(counter); 1100} 1101 1102class InstanceCollector { 1103 public: 1104 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1105 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1106 : class_(c), max_count_(max_count), instances_(instances) { 1107 } 1108 1109 void operator()(mirror::Object* o) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1110 mirror::Class* instance_class = o->GetClass(); 1111 if (instance_class == class_) { 1112 if (max_count_ == 0 || instances_.size() < max_count_) { 1113 instances_.push_back(o); 1114 } 1115 } 1116 } 1117 1118 private: 1119 mirror::Class* class_; 1120 uint32_t max_count_; 1121 std::vector<mirror::Object*>& instances_; 1122 1123 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1124}; 1125 1126void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1127 std::vector<mirror::Object*>& instances) { 1128 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1129 // is empty, so the live bitmap is the only place we need to look. 1130 Thread* self = Thread::Current(); 1131 self->TransitionFromRunnableToSuspended(kNative); 1132 CollectGarbage(false); 1133 self->TransitionFromSuspendedToRunnable(); 1134 1135 InstanceCollector collector(c, max_count, instances); 1136 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1137 GetLiveBitmap()->Visit(collector); 1138} 1139 1140class ReferringObjectsFinder { 1141 public: 1142 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1143 std::vector<mirror::Object*>& referring_objects) 1144 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1145 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1146 } 1147 1148 // For bitmap Visit. 1149 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1150 // annotalysis on visitors. 1151 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1152 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1153 } 1154 1155 // For MarkSweep::VisitObjectReferences. 1156 void operator()(mirror::Object* referrer, mirror::Object* object, 1157 const MemberOffset&, bool) const { 1158 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1159 referring_objects_.push_back(referrer); 1160 } 1161 } 1162 1163 private: 1164 mirror::Object* object_; 1165 uint32_t max_count_; 1166 std::vector<mirror::Object*>& referring_objects_; 1167 1168 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1169}; 1170 1171void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1172 std::vector<mirror::Object*>& referring_objects) { 1173 // We only want reachable instances, so do a GC. This also ensures that the alloc stack 1174 // is empty, so the live bitmap is the only place we need to look. 1175 Thread* self = Thread::Current(); 1176 self->TransitionFromRunnableToSuspended(kNative); 1177 CollectGarbage(false); 1178 self->TransitionFromSuspendedToRunnable(); 1179 1180 ReferringObjectsFinder finder(o, max_count, referring_objects); 1181 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 1182 GetLiveBitmap()->Visit(finder); 1183} 1184 1185void Heap::CollectGarbage(bool clear_soft_references) { 1186 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1187 // last GC will not have necessarily been cleared. 1188 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1189} 1190 1191void Heap::TransitionCollector(CollectorType collector_type) { 1192 if (collector_type == collector_type_) { 1193 return; 1194 } 1195 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1196 << " -> " << static_cast<int>(collector_type); 1197 uint64_t start_time = NanoTime(); 1198 uint32_t before_size = GetTotalMemory(); 1199 uint32_t before_allocated = num_bytes_allocated_.Load(); 1200 ThreadList* tl = Runtime::Current()->GetThreadList(); 1201 Thread* self = Thread::Current(); 1202 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1203 Locks::mutator_lock_->AssertNotHeld(self); 1204 const bool copying_transition = 1205 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1206 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1207 // compacting_gc_disable_count_, this should rarely occurs). 1208 for (;;) { 1209 { 1210 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1211 MutexLock mu(self, *gc_complete_lock_); 1212 // Ensure there is only one GC at a time. 1213 WaitForGcToCompleteLocked(self); 1214 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1215 if (!copying_transition || disable_moving_gc_count_ == 0) { 1216 // TODO: Not hard code in semi-space collector? 1217 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1218 break; 1219 } 1220 } 1221 usleep(1000); 1222 } 1223 tl->SuspendAll(); 1224 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1225 switch (collector_type) { 1226 case kCollectorTypeSS: 1227 // Fall-through. 1228 case kCollectorTypeGSS: { 1229 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1230 CHECK(main_space_ != nullptr); 1231 Compact(temp_space_, main_space_); 1232 DCHECK(allocator_mem_map_.get() == nullptr); 1233 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1234 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1235 // RemoveSpace does not delete the removed space. 1236 space::Space* old_space = main_space_; 1237 RemoveSpace(old_space); 1238 delete old_space; 1239 break; 1240 } 1241 case kCollectorTypeMS: 1242 // Fall through. 1243 case kCollectorTypeCMS: { 1244 if (IsCompactingGC(collector_type_)) { 1245 // TODO: Use mem-map from temp space? 1246 MemMap* mem_map = allocator_mem_map_.release(); 1247 CHECK(mem_map != nullptr); 1248 size_t initial_size = kDefaultInitialSize; 1249 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1250 CHECK(main_space_ == nullptr); 1251 if (kUseRosAlloc) { 1252 main_space_ = 1253 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1254 initial_size, mem_map->Size(), 1255 mem_map->Size(), low_memory_mode_); 1256 } else { 1257 main_space_ = 1258 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1259 initial_size, mem_map->Size(), 1260 mem_map->Size()); 1261 } 1262 main_space_->SetFootprintLimit(main_space_->Capacity()); 1263 AddSpace(main_space_); 1264 Compact(main_space_, bump_pointer_space_); 1265 } 1266 break; 1267 } 1268 default: { 1269 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1270 break; 1271 } 1272 } 1273 ChangeCollector(collector_type); 1274 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1275 tl->ResumeAll(); 1276 // Can't call into java code with all threads suspended. 1277 EnqueueClearedReferences(); 1278 uint64_t duration = NanoTime() - start_time; 1279 GrowForUtilization(collector::kGcTypeFull, duration); 1280 FinishGC(self, collector::kGcTypeFull); 1281 int32_t after_size = GetTotalMemory(); 1282 int32_t delta_size = before_size - after_size; 1283 int32_t after_allocated = num_bytes_allocated_.Load(); 1284 int32_t delta_allocated = before_allocated - after_allocated; 1285 const std::string saved_bytes_str = 1286 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1287 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1288 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1289 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1290 << PrettySize(delta_size) << " saved"; 1291} 1292 1293void Heap::ChangeCollector(CollectorType collector_type) { 1294 // TODO: Only do this with all mutators suspended to avoid races. 1295 if (collector_type != collector_type_) { 1296 collector_type_ = collector_type; 1297 gc_plan_.clear(); 1298 switch (collector_type_) { 1299 case kCollectorTypeSS: 1300 // Fall-through. 1301 case kCollectorTypeGSS: { 1302 concurrent_gc_ = false; 1303 gc_plan_.push_back(collector::kGcTypeFull); 1304 if (use_tlab_) { 1305 ChangeAllocator(kAllocatorTypeTLAB); 1306 } else { 1307 ChangeAllocator(kAllocatorTypeBumpPointer); 1308 } 1309 break; 1310 } 1311 case kCollectorTypeMS: { 1312 concurrent_gc_ = false; 1313 gc_plan_.push_back(collector::kGcTypeSticky); 1314 gc_plan_.push_back(collector::kGcTypePartial); 1315 gc_plan_.push_back(collector::kGcTypeFull); 1316 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1317 break; 1318 } 1319 case kCollectorTypeCMS: { 1320 concurrent_gc_ = true; 1321 gc_plan_.push_back(collector::kGcTypeSticky); 1322 gc_plan_.push_back(collector::kGcTypePartial); 1323 gc_plan_.push_back(collector::kGcTypeFull); 1324 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1325 break; 1326 } 1327 default: { 1328 LOG(FATAL) << "Unimplemented"; 1329 } 1330 } 1331 if (concurrent_gc_) { 1332 concurrent_start_bytes_ = 1333 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1334 } else { 1335 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1336 } 1337 } 1338} 1339 1340// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1341class ZygoteCompactingCollector : public collector::SemiSpace { 1342 public: 1343 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector") { 1344 } 1345 1346 void BuildBins(space::ContinuousSpace* space) { 1347 bin_live_bitmap_ = space->GetLiveBitmap(); 1348 bin_mark_bitmap_ = space->GetMarkBitmap(); 1349 BinContext context; 1350 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1351 context.collector_ = this; 1352 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1353 // Note: This requires traversing the space in increasing order of object addresses. 1354 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1355 // Add the last bin which spans after the last object to the end of the space. 1356 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1357 } 1358 1359 private: 1360 struct BinContext { 1361 uintptr_t prev_; // The end of the previous object. 1362 ZygoteCompactingCollector* collector_; 1363 }; 1364 // Maps from bin sizes to locations. 1365 std::multimap<size_t, uintptr_t> bins_; 1366 // Live bitmap of the space which contains the bins. 1367 accounting::SpaceBitmap* bin_live_bitmap_; 1368 // Mark bitmap of the space which contains the bins. 1369 accounting::SpaceBitmap* bin_mark_bitmap_; 1370 1371 static void Callback(mirror::Object* obj, void* arg) 1372 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1373 DCHECK(arg != nullptr); 1374 BinContext* context = reinterpret_cast<BinContext*>(arg); 1375 ZygoteCompactingCollector* collector = context->collector_; 1376 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1377 size_t bin_size = object_addr - context->prev_; 1378 // Add the bin consisting of the end of the previous object to the start of the current object. 1379 collector->AddBin(bin_size, context->prev_); 1380 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1381 } 1382 1383 void AddBin(size_t size, uintptr_t position) { 1384 if (size != 0) { 1385 bins_.insert(std::make_pair(size, position)); 1386 } 1387 } 1388 1389 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1390 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1391 // allocator. 1392 return false; 1393 } 1394 1395 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1396 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1397 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1398 mirror::Object* forward_address; 1399 // Find the smallest bin which we can move obj in. 1400 auto it = bins_.lower_bound(object_size); 1401 if (it == bins_.end()) { 1402 // No available space in the bins, place it in the target space instead (grows the zygote 1403 // space). 1404 size_t bytes_allocated; 1405 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated); 1406 if (to_space_live_bitmap_ != nullptr) { 1407 to_space_live_bitmap_->Set(forward_address); 1408 } else { 1409 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1410 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1411 } 1412 } else { 1413 size_t size = it->first; 1414 uintptr_t pos = it->second; 1415 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1416 forward_address = reinterpret_cast<mirror::Object*>(pos); 1417 // Set the live and mark bits so that sweeping system weaks works properly. 1418 bin_live_bitmap_->Set(forward_address); 1419 bin_mark_bitmap_->Set(forward_address); 1420 DCHECK_GE(size, object_size); 1421 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1422 } 1423 // Copy the object over to its new location. 1424 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1425 return forward_address; 1426 } 1427}; 1428 1429void Heap::UnBindBitmaps() { 1430 for (const auto& space : GetContinuousSpaces()) { 1431 if (space->IsContinuousMemMapAllocSpace()) { 1432 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1433 if (alloc_space->HasBoundBitmaps()) { 1434 alloc_space->UnBindBitmaps(); 1435 } 1436 } 1437 } 1438} 1439 1440void Heap::PreZygoteFork() { 1441 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1442 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1443 Thread* self = Thread::Current(); 1444 MutexLock mu(self, zygote_creation_lock_); 1445 // Try to see if we have any Zygote spaces. 1446 if (have_zygote_space_) { 1447 return; 1448 } 1449 VLOG(heap) << "Starting PreZygoteFork"; 1450 // Trim the pages at the end of the non moving space. 1451 non_moving_space_->Trim(); 1452 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1453 // Change the collector to the post zygote one. 1454 ChangeCollector(post_zygote_collector_type_); 1455 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1456 if (semi_space_collector_ != nullptr) { 1457 // Temporarily disable rosalloc verification because the zygote 1458 // compaction will mess up the rosalloc internal metadata. 1459 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1460 ZygoteCompactingCollector zygote_collector(this); 1461 zygote_collector.BuildBins(non_moving_space_); 1462 // Create a new bump pointer space which we will compact into. 1463 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1464 non_moving_space_->Limit()); 1465 // Compact the bump pointer space to a new zygote bump pointer space. 1466 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1467 zygote_collector.SetFromSpace(bump_pointer_space_); 1468 zygote_collector.SetToSpace(&target_space); 1469 zygote_collector.Run(kGcCauseCollectorTransition, false); 1470 CHECK(temp_space_->IsEmpty()); 1471 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1472 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1473 // Update the end and write out image. 1474 non_moving_space_->SetEnd(target_space.End()); 1475 non_moving_space_->SetLimit(target_space.Limit()); 1476 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1477 } 1478 // Save the old space so that we can remove it after we complete creating the zygote space. 1479 space::MallocSpace* old_alloc_space = non_moving_space_; 1480 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1481 // the remaining available space. 1482 // Remove the old space before creating the zygote space since creating the zygote space sets 1483 // the old alloc space's bitmaps to nullptr. 1484 RemoveSpace(old_alloc_space); 1485 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1486 low_memory_mode_, 1487 &main_space_); 1488 delete old_alloc_space; 1489 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1490 AddSpace(zygote_space, false); 1491 CHECK(main_space_ != nullptr); 1492 if (main_space_->IsRosAllocSpace()) { 1493 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1494 } else if (main_space_->IsDlMallocSpace()) { 1495 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1496 } 1497 main_space_->SetFootprintLimit(main_space_->Capacity()); 1498 AddSpace(main_space_); 1499 have_zygote_space_ = true; 1500 // Create the zygote space mod union table. 1501 accounting::ModUnionTable* mod_union_table = 1502 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1503 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1504 AddModUnionTable(mod_union_table); 1505 // Reset the cumulative loggers since we now have a few additional timing phases. 1506 for (const auto& collector : garbage_collectors_) { 1507 collector->ResetCumulativeStatistics(); 1508 } 1509 // Can't use RosAlloc for non moving space due to thread local buffers. 1510 // TODO: Non limited space for non-movable objects? 1511 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1512 space::MallocSpace* new_non_moving_space = 1513 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1514 2 * MB, mem_map->Size(), mem_map->Size()); 1515 AddSpace(new_non_moving_space, false); 1516 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1517 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1518 non_moving_space_ = new_non_moving_space; 1519} 1520 1521void Heap::FlushAllocStack() { 1522 MarkAllocStackAsLive(allocation_stack_.get()); 1523 allocation_stack_->Reset(); 1524} 1525 1526void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1527 accounting::SpaceBitmap* bitmap2, 1528 accounting::ObjectSet* large_objects, 1529 accounting::ObjectStack* stack) { 1530 DCHECK(bitmap1 != nullptr); 1531 DCHECK(bitmap2 != nullptr); 1532 mirror::Object** limit = stack->End(); 1533 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1534 const mirror::Object* obj = *it; 1535 DCHECK(obj != nullptr); 1536 if (bitmap1->HasAddress(obj)) { 1537 bitmap1->Set(obj); 1538 } else if (bitmap2->HasAddress(obj)) { 1539 bitmap2->Set(obj); 1540 } else { 1541 large_objects->Set(obj); 1542 } 1543 } 1544} 1545 1546void Heap::SwapSemiSpaces() { 1547 // Swap the spaces so we allocate into the space which we just evacuated. 1548 std::swap(bump_pointer_space_, temp_space_); 1549} 1550 1551void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1552 space::ContinuousMemMapAllocSpace* source_space) { 1553 CHECK(kMovingCollector); 1554 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1555 if (target_space != source_space) { 1556 semi_space_collector_->SetFromSpace(source_space); 1557 semi_space_collector_->SetToSpace(target_space); 1558 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1559 } 1560} 1561 1562collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1563 bool clear_soft_references) { 1564 Thread* self = Thread::Current(); 1565 Runtime* runtime = Runtime::Current(); 1566 // If the heap can't run the GC, silently fail and return that no GC was run. 1567 switch (gc_type) { 1568 case collector::kGcTypePartial: { 1569 if (!have_zygote_space_) { 1570 return collector::kGcTypeNone; 1571 } 1572 break; 1573 } 1574 default: { 1575 // Other GC types don't have any special cases which makes them not runnable. The main case 1576 // here is full GC. 1577 } 1578 } 1579 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1580 Locks::mutator_lock_->AssertNotHeld(self); 1581 if (self->IsHandlingStackOverflow()) { 1582 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1583 } 1584 bool compacting_gc; 1585 { 1586 gc_complete_lock_->AssertNotHeld(self); 1587 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1588 MutexLock mu(self, *gc_complete_lock_); 1589 // Ensure there is only one GC at a time. 1590 WaitForGcToCompleteLocked(self); 1591 compacting_gc = IsCompactingGC(collector_type_); 1592 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1593 if (compacting_gc && disable_moving_gc_count_ != 0) { 1594 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1595 return collector::kGcTypeNone; 1596 } 1597 collector_type_running_ = collector_type_; 1598 } 1599 1600 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1601 ++runtime->GetStats()->gc_for_alloc_count; 1602 ++self->GetStats()->gc_for_alloc_count; 1603 } 1604 uint64_t gc_start_time_ns = NanoTime(); 1605 uint64_t gc_start_size = GetBytesAllocated(); 1606 // Approximate allocation rate in bytes / second. 1607 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1608 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1609 if (LIKELY(ms_delta != 0)) { 1610 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1611 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1612 } 1613 1614 DCHECK_LT(gc_type, collector::kGcTypeMax); 1615 DCHECK_NE(gc_type, collector::kGcTypeNone); 1616 1617 collector::GarbageCollector* collector = nullptr; 1618 // TODO: Clean this up. 1619 if (compacting_gc) { 1620 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1621 current_allocator_ == kAllocatorTypeTLAB); 1622 gc_type = semi_space_collector_->GetGcType(); 1623 CHECK(temp_space_->IsEmpty()); 1624 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1625 semi_space_collector_->SetToSpace(temp_space_); 1626 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1627 collector = semi_space_collector_; 1628 gc_type = collector::kGcTypeFull; 1629 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1630 current_allocator_ == kAllocatorTypeDlMalloc) { 1631 for (const auto& cur_collector : garbage_collectors_) { 1632 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1633 cur_collector->GetGcType() == gc_type) { 1634 collector = cur_collector; 1635 break; 1636 } 1637 } 1638 } else { 1639 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1640 } 1641 CHECK(collector != nullptr) 1642 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1643 << " and type=" << gc_type; 1644 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1645 collector->Run(gc_cause, clear_soft_references); 1646 total_objects_freed_ever_ += collector->GetFreedObjects(); 1647 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1648 // Enqueue cleared references. 1649 EnqueueClearedReferences(); 1650 // Grow the heap so that we know when to perform the next GC. 1651 GrowForUtilization(gc_type, collector->GetDurationNs()); 1652 if (CareAboutPauseTimes()) { 1653 const size_t duration = collector->GetDurationNs(); 1654 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1655 // GC for alloc pauses the allocating thread, so consider it as a pause. 1656 bool was_slow = duration > long_gc_log_threshold_ || 1657 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1658 if (!was_slow) { 1659 for (uint64_t pause : pauses) { 1660 was_slow = was_slow || pause > long_pause_log_threshold_; 1661 } 1662 } 1663 if (was_slow) { 1664 const size_t percent_free = GetPercentFree(); 1665 const size_t current_heap_size = GetBytesAllocated(); 1666 const size_t total_memory = GetTotalMemory(); 1667 std::ostringstream pause_string; 1668 for (size_t i = 0; i < pauses.size(); ++i) { 1669 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1670 << ((i != pauses.size() - 1) ? ", " : ""); 1671 } 1672 LOG(INFO) << gc_cause << " " << collector->GetName() 1673 << " GC freed " << collector->GetFreedObjects() << "(" 1674 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1675 << collector->GetFreedLargeObjects() << "(" 1676 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1677 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1678 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1679 << " total " << PrettyDuration((duration / 1000) * 1000); 1680 if (VLOG_IS_ON(heap)) { 1681 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1682 } 1683 } 1684 } 1685 FinishGC(self, gc_type); 1686 ATRACE_END(); 1687 1688 // Inform DDMS that a GC completed. 1689 Dbg::GcDidFinish(); 1690 return gc_type; 1691} 1692 1693void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1694 MutexLock mu(self, *gc_complete_lock_); 1695 collector_type_running_ = kCollectorTypeNone; 1696 if (gc_type != collector::kGcTypeNone) { 1697 last_gc_type_ = gc_type; 1698 } 1699 // Wake anyone who may have been waiting for the GC to complete. 1700 gc_complete_cond_->Broadcast(self); 1701} 1702 1703static mirror::Object* RootMatchesObjectVisitor(mirror::Object* root, void* arg) { 1704 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1705 if (root == obj) { 1706 LOG(INFO) << "Object " << obj << " is a root"; 1707 } 1708 return root; 1709} 1710 1711class ScanVisitor { 1712 public: 1713 void operator()(const mirror::Object* obj) const { 1714 LOG(ERROR) << "Would have rescanned object " << obj; 1715 } 1716}; 1717 1718// Verify a reference from an object. 1719class VerifyReferenceVisitor { 1720 public: 1721 explicit VerifyReferenceVisitor(Heap* heap) 1722 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1723 : heap_(heap), failed_(false) {} 1724 1725 bool Failed() const { 1726 return failed_; 1727 } 1728 1729 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1730 // analysis on visitors. 1731 void operator()(mirror::Object* obj, mirror::Object* ref, 1732 const MemberOffset& offset, bool /* is_static */) const 1733 NO_THREAD_SAFETY_ANALYSIS { 1734 if (ref == nullptr || IsLive(ref)) { 1735 // Verify that the reference is live. 1736 return; 1737 } 1738 if (!failed_) { 1739 // Print message on only on first failure to prevent spam. 1740 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1741 failed_ = true; 1742 } 1743 if (obj != nullptr) { 1744 accounting::CardTable* card_table = heap_->GetCardTable(); 1745 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1746 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1747 byte* card_addr = card_table->CardFromAddr(obj); 1748 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1749 << offset << "\n card value = " << static_cast<int>(*card_addr); 1750 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1751 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1752 } else { 1753 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1754 } 1755 1756 // Attmept to find the class inside of the recently freed objects. 1757 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1758 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1759 space::MallocSpace* space = ref_space->AsMallocSpace(); 1760 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1761 if (ref_class != nullptr) { 1762 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1763 << PrettyClass(ref_class); 1764 } else { 1765 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1766 } 1767 } 1768 1769 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1770 ref->GetClass()->IsClass()) { 1771 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1772 } else { 1773 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1774 << ") is not a valid heap address"; 1775 } 1776 1777 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1778 void* cover_begin = card_table->AddrFromCard(card_addr); 1779 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1780 accounting::CardTable::kCardSize); 1781 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1782 << "-" << cover_end; 1783 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1784 1785 if (bitmap == nullptr) { 1786 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1787 if (!heap_->VerifyClassClass(obj->GetClass())) { 1788 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1789 } 1790 } else { 1791 // Print out how the object is live. 1792 if (bitmap->Test(obj)) { 1793 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1794 } 1795 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1796 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1797 } 1798 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1799 LOG(ERROR) << "Object " << obj << " found in live stack"; 1800 } 1801 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1802 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1803 } 1804 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1805 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1806 } 1807 // Attempt to see if the card table missed the reference. 1808 ScanVisitor scan_visitor; 1809 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1810 card_table->Scan(bitmap, byte_cover_begin, 1811 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1812 } 1813 1814 // Search to see if any of the roots reference our object. 1815 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1816 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1817 1818 // Search to see if any of the roots reference our reference. 1819 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1820 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg, false, false); 1821 } else { 1822 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 1823 } 1824 } 1825 1826 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1827 return heap_->IsLiveObjectLocked(obj, true, false, true); 1828 } 1829 1830 static mirror::Object* VerifyRoots(mirror::Object* root, void* arg) { 1831 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1832 (*visitor)(nullptr, root, MemberOffset(0), true); 1833 return root; 1834 } 1835 1836 private: 1837 Heap* const heap_; 1838 mutable bool failed_; 1839}; 1840 1841// Verify all references within an object, for use with HeapBitmap::Visit. 1842class VerifyObjectVisitor { 1843 public: 1844 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1845 1846 void operator()(mirror::Object* obj) const 1847 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1848 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1849 // be live or else how did we find it in the live bitmap? 1850 VerifyReferenceVisitor visitor(heap_); 1851 // The class doesn't count as a reference but we should verify it anyways. 1852 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1853 if (obj->GetClass()->IsReferenceClass()) { 1854 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1855 } 1856 failed_ = failed_ || visitor.Failed(); 1857 } 1858 1859 static void VisitCallback(mirror::Object* obj, void* arg) 1860 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1861 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1862 visitor->operator()(obj); 1863 } 1864 1865 bool Failed() const { 1866 return failed_; 1867 } 1868 1869 private: 1870 Heap* const heap_; 1871 mutable bool failed_; 1872}; 1873 1874// Must do this with mutators suspended since we are directly accessing the allocation stacks. 1875bool Heap::VerifyHeapReferences() { 1876 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1877 // Lets sort our allocation stacks so that we can efficiently binary search them. 1878 allocation_stack_->Sort(); 1879 live_stack_->Sort(); 1880 VerifyObjectVisitor visitor(this); 1881 // Verify objects in the allocation stack since these will be objects which were: 1882 // 1. Allocated prior to the GC (pre GC verification). 1883 // 2. Allocated during the GC (pre sweep GC verification). 1884 // We don't want to verify the objects in the live stack since they themselves may be 1885 // pointing to dead objects if they are not reachable. 1886 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 1887 // Verify the roots: 1888 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor, false, false); 1889 if (visitor.Failed()) { 1890 // Dump mod-union tables. 1891 for (const auto& table_pair : mod_union_tables_) { 1892 accounting::ModUnionTable* mod_union_table = table_pair.second; 1893 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 1894 } 1895 DumpSpaces(); 1896 return false; 1897 } 1898 return true; 1899} 1900 1901class VerifyReferenceCardVisitor { 1902 public: 1903 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 1904 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 1905 Locks::heap_bitmap_lock_) 1906 : heap_(heap), failed_(failed) { 1907 } 1908 1909 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1910 // annotalysis on visitors. 1911 void operator()(mirror::Object* obj, mirror::Object* ref, const MemberOffset& offset, 1912 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 1913 // Filter out class references since changing an object's class does not mark the card as dirty. 1914 // Also handles large objects, since the only reference they hold is a class reference. 1915 if (ref != NULL && !ref->IsClass()) { 1916 accounting::CardTable* card_table = heap_->GetCardTable(); 1917 // If the object is not dirty and it is referencing something in the live stack other than 1918 // class, then it must be on a dirty card. 1919 if (!card_table->AddrIsInCardTable(obj)) { 1920 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 1921 *failed_ = true; 1922 } else if (!card_table->IsDirty(obj)) { 1923 // TODO: Check mod-union tables. 1924 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 1925 // kCardDirty - 1 if it didnt get touched since we aged it. 1926 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1927 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 1928 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1929 LOG(ERROR) << "Object " << obj << " found in live stack"; 1930 } 1931 if (heap_->GetLiveBitmap()->Test(obj)) { 1932 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1933 } 1934 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 1935 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 1936 1937 // Print which field of the object is dead. 1938 if (!obj->IsObjectArray()) { 1939 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 1940 CHECK(klass != NULL); 1941 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 1942 : klass->GetIFields(); 1943 CHECK(fields != NULL); 1944 for (int32_t i = 0; i < fields->GetLength(); ++i) { 1945 mirror::ArtField* cur = fields->Get(i); 1946 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 1947 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 1948 << PrettyField(cur); 1949 break; 1950 } 1951 } 1952 } else { 1953 mirror::ObjectArray<mirror::Object>* object_array = 1954 obj->AsObjectArray<mirror::Object>(); 1955 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 1956 if (object_array->Get(i) == ref) { 1957 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 1958 } 1959 } 1960 } 1961 1962 *failed_ = true; 1963 } 1964 } 1965 } 1966 } 1967 1968 private: 1969 Heap* const heap_; 1970 bool* const failed_; 1971}; 1972 1973class VerifyLiveStackReferences { 1974 public: 1975 explicit VerifyLiveStackReferences(Heap* heap) 1976 : heap_(heap), 1977 failed_(false) {} 1978 1979 void operator()(mirror::Object* obj) const 1980 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1981 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 1982 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 1983 } 1984 1985 bool Failed() const { 1986 return failed_; 1987 } 1988 1989 private: 1990 Heap* const heap_; 1991 bool failed_; 1992}; 1993 1994bool Heap::VerifyMissingCardMarks() { 1995 Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current()); 1996 1997 // We need to sort the live stack since we binary search it. 1998 live_stack_->Sort(); 1999 VerifyLiveStackReferences visitor(this); 2000 GetLiveBitmap()->Visit(visitor); 2001 2002 // We can verify objects in the live stack since none of these should reference dead objects. 2003 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2004 visitor(*it); 2005 } 2006 2007 if (visitor.Failed()) { 2008 DumpSpaces(); 2009 return false; 2010 } 2011 return true; 2012} 2013 2014void Heap::SwapStacks() { 2015 allocation_stack_.swap(live_stack_); 2016} 2017 2018accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2019 auto it = mod_union_tables_.find(space); 2020 if (it == mod_union_tables_.end()) { 2021 return nullptr; 2022 } 2023 return it->second; 2024} 2025 2026void Heap::ProcessCards(TimingLogger& timings) { 2027 // Clear cards and keep track of cards cleared in the mod-union table. 2028 for (const auto& space : continuous_spaces_) { 2029 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2030 if (table != nullptr) { 2031 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2032 "ImageModUnionClearCards"; 2033 TimingLogger::ScopedSplit split(name, &timings); 2034 table->ClearCards(); 2035 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2036 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2037 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2038 // were dirty before the GC started. 2039 // TODO: Don't need to use atomic. 2040 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2041 // roots and then we scan / update mod union tables after. We will always scan either card. 2042 // If we end up with the non aged card, we scan it it in the pause. 2043 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2044 } 2045 } 2046} 2047 2048static mirror::Object* IdentityCallback(mirror::Object* obj, void*) { 2049 return obj; 2050} 2051 2052void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2053 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2054 Thread* self = Thread::Current(); 2055 2056 if (verify_pre_gc_heap_) { 2057 thread_list->SuspendAll(); 2058 { 2059 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2060 if (!VerifyHeapReferences()) { 2061 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2062 } 2063 } 2064 thread_list->ResumeAll(); 2065 } 2066 2067 // Check that all objects which reference things in the live stack are on dirty cards. 2068 if (verify_missing_card_marks_) { 2069 thread_list->SuspendAll(); 2070 { 2071 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2072 SwapStacks(); 2073 // Sort the live stack so that we can quickly binary search it later. 2074 if (!VerifyMissingCardMarks()) { 2075 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2076 } 2077 SwapStacks(); 2078 } 2079 thread_list->ResumeAll(); 2080 } 2081 2082 if (verify_mod_union_table_) { 2083 thread_list->SuspendAll(); 2084 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2085 for (const auto& table_pair : mod_union_tables_) { 2086 accounting::ModUnionTable* mod_union_table = table_pair.second; 2087 mod_union_table->UpdateAndMarkReferences(IdentityCallback, nullptr); 2088 mod_union_table->Verify(); 2089 } 2090 thread_list->ResumeAll(); 2091 } 2092} 2093 2094void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2095 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2096 // reachable objects. 2097 if (verify_post_gc_heap_) { 2098 Thread* self = Thread::Current(); 2099 CHECK_NE(self->GetState(), kRunnable); 2100 { 2101 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2102 // Swapping bound bitmaps does nothing. 2103 gc->SwapBitmaps(); 2104 if (!VerifyHeapReferences()) { 2105 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2106 } 2107 gc->SwapBitmaps(); 2108 } 2109 } 2110} 2111 2112void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2113 if (verify_system_weaks_) { 2114 Thread* self = Thread::Current(); 2115 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2116 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2117 mark_sweep->VerifySystemWeaks(); 2118 } 2119} 2120 2121void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2122 if (verify_pre_gc_rosalloc_) { 2123 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2124 for (const auto& space : continuous_spaces_) { 2125 if (space->IsRosAllocSpace()) { 2126 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2127 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2128 rosalloc_space->Verify(); 2129 } 2130 } 2131 } 2132} 2133 2134void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2135 if (verify_post_gc_rosalloc_) { 2136 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2137 for (const auto& space : continuous_spaces_) { 2138 if (space->IsRosAllocSpace()) { 2139 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2140 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2141 rosalloc_space->Verify(); 2142 } 2143 } 2144 } 2145} 2146 2147collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2148 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2149 MutexLock mu(self, *gc_complete_lock_); 2150 return WaitForGcToCompleteLocked(self); 2151} 2152 2153collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2154 collector::GcType last_gc_type = collector::kGcTypeNone; 2155 uint64_t wait_start = NanoTime(); 2156 while (collector_type_running_ != kCollectorTypeNone) { 2157 ATRACE_BEGIN("GC: Wait For Completion"); 2158 // We must wait, change thread state then sleep on gc_complete_cond_; 2159 gc_complete_cond_->Wait(self); 2160 last_gc_type = last_gc_type_; 2161 ATRACE_END(); 2162 } 2163 uint64_t wait_time = NanoTime() - wait_start; 2164 total_wait_time_ += wait_time; 2165 if (wait_time > long_pause_log_threshold_) { 2166 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2167 } 2168 return last_gc_type; 2169} 2170 2171void Heap::DumpForSigQuit(std::ostream& os) { 2172 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2173 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2174 DumpGcPerformanceInfo(os); 2175} 2176 2177size_t Heap::GetPercentFree() { 2178 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2179} 2180 2181void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2182 if (max_allowed_footprint > GetMaxMemory()) { 2183 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2184 << PrettySize(GetMaxMemory()); 2185 max_allowed_footprint = GetMaxMemory(); 2186 } 2187 max_allowed_footprint_ = max_allowed_footprint; 2188} 2189 2190bool Heap::IsMovableObject(const mirror::Object* obj) const { 2191 if (kMovingCollector) { 2192 DCHECK(!IsInTempSpace(obj)); 2193 if (bump_pointer_space_->HasAddress(obj)) { 2194 return true; 2195 } 2196 // TODO: Refactor this logic into the space itself? 2197 // Objects in the main space are only copied during background -> foreground transitions or 2198 // visa versa. 2199 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2200 (IsCompactingGC(background_collector_type_) || 2201 IsCompactingGC(post_zygote_collector_type_))) { 2202 return true; 2203 } 2204 } 2205 return false; 2206} 2207 2208bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2209 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2210 return true; 2211 } 2212 return false; 2213} 2214 2215void Heap::UpdateMaxNativeFootprint() { 2216 size_t native_size = native_bytes_allocated_; 2217 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2218 size_t target_size = native_size / GetTargetHeapUtilization(); 2219 if (target_size > native_size + max_free_) { 2220 target_size = native_size + max_free_; 2221 } else if (target_size < native_size + min_free_) { 2222 target_size = native_size + min_free_; 2223 } 2224 native_footprint_gc_watermark_ = target_size; 2225 native_footprint_limit_ = 2 * target_size - native_size; 2226} 2227 2228void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2229 // We know what our utilization is at this moment. 2230 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2231 const size_t bytes_allocated = GetBytesAllocated(); 2232 last_gc_size_ = bytes_allocated; 2233 last_gc_time_ns_ = NanoTime(); 2234 size_t target_size; 2235 if (gc_type != collector::kGcTypeSticky) { 2236 // Grow the heap for non sticky GC. 2237 target_size = bytes_allocated / GetTargetHeapUtilization(); 2238 if (target_size > bytes_allocated + max_free_) { 2239 target_size = bytes_allocated + max_free_; 2240 } else if (target_size < bytes_allocated + min_free_) { 2241 target_size = bytes_allocated + min_free_; 2242 } 2243 native_need_to_run_finalization_ = true; 2244 next_gc_type_ = collector::kGcTypeSticky; 2245 } else { 2246 // Based on how close the current heap size is to the target size, decide 2247 // whether or not to do a partial or sticky GC next. 2248 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2249 next_gc_type_ = collector::kGcTypeSticky; 2250 } else { 2251 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2252 } 2253 // If we have freed enough memory, shrink the heap back down. 2254 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2255 target_size = bytes_allocated + max_free_; 2256 } else { 2257 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2258 } 2259 } 2260 if (!ignore_max_footprint_) { 2261 SetIdealFootprint(target_size); 2262 if (concurrent_gc_) { 2263 // Calculate when to perform the next ConcurrentGC. 2264 // Calculate the estimated GC duration. 2265 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2266 // Estimate how many remaining bytes we will have when we need to start the next GC. 2267 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2268 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2269 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2270 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2271 // A never going to happen situation that from the estimated allocation rate we will exceed 2272 // the applications entire footprint with the given estimated allocation rate. Schedule 2273 // another GC nearly straight away. 2274 remaining_bytes = kMinConcurrentRemainingBytes; 2275 } 2276 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2277 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2278 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2279 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2280 // right away. 2281 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2282 } 2283 } 2284} 2285 2286void Heap::ClearGrowthLimit() { 2287 growth_limit_ = capacity_; 2288 non_moving_space_->ClearGrowthLimit(); 2289} 2290 2291void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2292 MemberOffset reference_queue_offset, 2293 MemberOffset reference_queueNext_offset, 2294 MemberOffset reference_pendingNext_offset, 2295 MemberOffset finalizer_reference_zombie_offset) { 2296 reference_referent_offset_ = reference_referent_offset; 2297 reference_queue_offset_ = reference_queue_offset; 2298 reference_queueNext_offset_ = reference_queueNext_offset; 2299 reference_pendingNext_offset_ = reference_pendingNext_offset; 2300 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2301 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2302 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2303 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2304 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2305 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2306} 2307 2308void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2309 DCHECK(reference != NULL); 2310 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2311 reference->SetFieldObject(reference_referent_offset_, referent, true); 2312} 2313 2314mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2315 DCHECK(reference != NULL); 2316 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2317 return reference->GetFieldObject<mirror::Object>(reference_referent_offset_, true); 2318} 2319 2320void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2321 ScopedObjectAccess soa(self); 2322 JValue result; 2323 ArgArray arg_array(NULL, 0); 2324 arg_array.Append(object); 2325 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2326 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2327} 2328 2329void Heap::EnqueueClearedReferences() { 2330 Thread* self = Thread::Current(); 2331 Locks::mutator_lock_->AssertNotHeld(self); 2332 if (!cleared_references_.IsEmpty()) { 2333 // When a runtime isn't started there are no reference queues to care about so ignore. 2334 if (LIKELY(Runtime::Current()->IsStarted())) { 2335 ScopedObjectAccess soa(self); 2336 JValue result; 2337 ArgArray arg_array(NULL, 0); 2338 arg_array.Append(cleared_references_.GetList()); 2339 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2340 arg_array.GetArray(), arg_array.GetNumBytes(), &result, 'V'); 2341 } 2342 cleared_references_.Clear(); 2343 } 2344} 2345 2346void Heap::RequestConcurrentGC(Thread* self) { 2347 // Make sure that we can do a concurrent GC. 2348 Runtime* runtime = Runtime::Current(); 2349 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2350 self->IsHandlingStackOverflow()) { 2351 return; 2352 } 2353 // We already have a request pending, no reason to start more until we update 2354 // concurrent_start_bytes_. 2355 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2356 JNIEnv* env = self->GetJniEnv(); 2357 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2358 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2359 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2360 WellKnownClasses::java_lang_Daemons_requestGC); 2361 CHECK(!env->ExceptionCheck()); 2362} 2363 2364void Heap::ConcurrentGC(Thread* self) { 2365 if (Runtime::Current()->IsShuttingDown(self)) { 2366 return; 2367 } 2368 // Wait for any GCs currently running to finish. 2369 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2370 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2371 // instead. E.g. can't do partial, so do full instead. 2372 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2373 collector::kGcTypeNone) { 2374 for (collector::GcType gc_type : gc_plan_) { 2375 // Attempt to run the collector, if we succeed, we are done. 2376 if (gc_type > next_gc_type_ && 2377 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2378 break; 2379 } 2380 } 2381 } 2382 } 2383} 2384 2385void Heap::RequestHeapTrim() { 2386 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2387 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2388 // a space it will hold its lock and can become a cause of jank. 2389 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2390 // forking. 2391 2392 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2393 // because that only marks object heads, so a large array looks like lots of empty space. We 2394 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2395 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2396 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2397 // not how much use we're making of those pages. 2398 uint64_t ms_time = MilliTime(); 2399 // Don't bother trimming the alloc space if a heap trim occurred in the last two seconds. 2400 if (ms_time - last_trim_time_ms_ < 2 * 1000) { 2401 return; 2402 } 2403 2404 Thread* self = Thread::Current(); 2405 Runtime* runtime = Runtime::Current(); 2406 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2407 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2408 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2409 // as we don't hold the lock while requesting the trim). 2410 return; 2411 } 2412 2413 last_trim_time_ms_ = ms_time; 2414 2415 // Trim only if we do not currently care about pause times. 2416 if (!CareAboutPauseTimes()) { 2417 JNIEnv* env = self->GetJniEnv(); 2418 DCHECK(WellKnownClasses::java_lang_Daemons != NULL); 2419 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != NULL); 2420 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2421 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2422 CHECK(!env->ExceptionCheck()); 2423 } 2424} 2425 2426void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2427 if (rosalloc_space_ != nullptr) { 2428 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2429 } 2430 if (bump_pointer_space_ != nullptr) { 2431 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2432 } 2433} 2434 2435void Heap::RevokeAllThreadLocalBuffers() { 2436 if (rosalloc_space_ != nullptr) { 2437 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2438 } 2439 if (bump_pointer_space_ != nullptr) { 2440 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2441 } 2442} 2443 2444bool Heap::IsGCRequestPending() const { 2445 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2446} 2447 2448void Heap::RunFinalization(JNIEnv* env) { 2449 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2450 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2451 CHECK(WellKnownClasses::java_lang_System != nullptr); 2452 WellKnownClasses::java_lang_System_runFinalization = 2453 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2454 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2455 } 2456 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2457 WellKnownClasses::java_lang_System_runFinalization); 2458} 2459 2460void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2461 Thread* self = ThreadForEnv(env); 2462 if (native_need_to_run_finalization_) { 2463 RunFinalization(env); 2464 UpdateMaxNativeFootprint(); 2465 native_need_to_run_finalization_ = false; 2466 } 2467 // Total number of native bytes allocated. 2468 native_bytes_allocated_.FetchAndAdd(bytes); 2469 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2470 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2471 collector::kGcTypeFull; 2472 2473 // The second watermark is higher than the gc watermark. If you hit this it means you are 2474 // allocating native objects faster than the GC can keep up with. 2475 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2476 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2477 // Just finished a GC, attempt to run finalizers. 2478 RunFinalization(env); 2479 CHECK(!env->ExceptionCheck()); 2480 } 2481 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2482 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2483 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2484 RunFinalization(env); 2485 native_need_to_run_finalization_ = false; 2486 CHECK(!env->ExceptionCheck()); 2487 } 2488 // We have just run finalizers, update the native watermark since it is very likely that 2489 // finalizers released native managed allocations. 2490 UpdateMaxNativeFootprint(); 2491 } else if (!IsGCRequestPending()) { 2492 if (concurrent_gc_) { 2493 RequestConcurrentGC(self); 2494 } else { 2495 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2496 } 2497 } 2498 } 2499} 2500 2501void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2502 int expected_size, new_size; 2503 do { 2504 expected_size = native_bytes_allocated_.Load(); 2505 new_size = expected_size - bytes; 2506 if (UNLIKELY(new_size < 0)) { 2507 ScopedObjectAccess soa(env); 2508 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2509 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2510 "registered as allocated", bytes, expected_size).c_str()); 2511 break; 2512 } 2513 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2514} 2515 2516size_t Heap::GetTotalMemory() const { 2517 size_t ret = 0; 2518 for (const auto& space : continuous_spaces_) { 2519 // Currently don't include the image space. 2520 if (!space->IsImageSpace()) { 2521 ret += space->Size(); 2522 } 2523 } 2524 for (const auto& space : discontinuous_spaces_) { 2525 if (space->IsLargeObjectSpace()) { 2526 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2527 } 2528 } 2529 return ret; 2530} 2531 2532void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2533 DCHECK(mod_union_table != nullptr); 2534 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2535} 2536 2537} // namespace gc 2538} // namespace art 2539