heap.cc revision c645f1ddb7c40bea6a38eda4b3f83f6b6dec405b
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 "entrypoints/quick/quick_alloc_entrypoints.h" 49#include "heap-inl.h" 50#include "image.h" 51#include "invoke_arg_array_builder.h" 52#include "mirror/art_field-inl.h" 53#include "mirror/class-inl.h" 54#include "mirror/object.h" 55#include "mirror/object-inl.h" 56#include "mirror/object_array-inl.h" 57#include "object_utils.h" 58#include "os.h" 59#include "runtime.h" 60#include "ScopedLocalRef.h" 61#include "scoped_thread_state_change.h" 62#include "sirt_ref.h" 63#include "thread_list.h" 64#include "UniquePtr.h" 65#include "well_known_classes.h" 66 67namespace art { 68 69namespace gc { 70 71static constexpr bool kGCALotMode = false; 72static constexpr size_t kGcAlotInterval = KB; 73// Minimum amount of remaining bytes before a concurrent GC is triggered. 74static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 75static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 76 77Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 78 double target_utilization, size_t capacity, const std::string& image_file_name, 79 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 80 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 81 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 82 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 83 bool verify_post_gc_heap, bool verify_pre_gc_rosalloc, 84 bool verify_post_gc_rosalloc) 85 : non_moving_space_(nullptr), 86 rosalloc_space_(nullptr), 87 dlmalloc_space_(nullptr), 88 main_space_(nullptr), 89 concurrent_gc_(false), 90 collector_type_(kCollectorTypeNone), 91 post_zygote_collector_type_(post_zygote_collector_type), 92 background_collector_type_(background_collector_type), 93 desired_collector_type_(collector_type_), 94 heap_trim_request_lock_(nullptr), 95 heap_trim_target_time_(0), 96 heap_transition_target_time_(0), 97 heap_trim_request_pending_(false), 98 parallel_gc_threads_(parallel_gc_threads), 99 conc_gc_threads_(conc_gc_threads), 100 low_memory_mode_(low_memory_mode), 101 long_pause_log_threshold_(long_pause_log_threshold), 102 long_gc_log_threshold_(long_gc_log_threshold), 103 ignore_max_footprint_(ignore_max_footprint), 104 have_zygote_space_(false), 105 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 106 soft_reference_queue_(this), 107 weak_reference_queue_(this), 108 finalizer_reference_queue_(this), 109 phantom_reference_queue_(this), 110 cleared_references_(this), 111 collector_type_running_(kCollectorTypeNone), 112 last_gc_type_(collector::kGcTypeNone), 113 next_gc_type_(collector::kGcTypePartial), 114 capacity_(capacity), 115 growth_limit_(growth_limit), 116 max_allowed_footprint_(initial_size), 117 native_footprint_gc_watermark_(initial_size), 118 native_footprint_limit_(2 * initial_size), 119 native_need_to_run_finalization_(false), 120 // Initially assume we perceive jank in case the process state is never updated. 121 process_state_(kProcessStateJankPerceptible), 122 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 123 total_bytes_freed_ever_(0), 124 total_objects_freed_ever_(0), 125 num_bytes_allocated_(0), 126 native_bytes_allocated_(0), 127 gc_memory_overhead_(0), 128 verify_missing_card_marks_(false), 129 verify_system_weaks_(false), 130 verify_pre_gc_heap_(verify_pre_gc_heap), 131 verify_post_gc_heap_(verify_post_gc_heap), 132 verify_mod_union_table_(false), 133 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 134 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 135 allocation_rate_(0), 136 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 137 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 138 * verification is enabled, we limit the size of allocation stacks to speed up their 139 * searching. 140 */ 141 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 142 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 143 current_allocator_(kAllocatorTypeDlMalloc), 144 current_non_moving_allocator_(kAllocatorTypeNonMoving), 145 bump_pointer_space_(nullptr), 146 temp_space_(nullptr), 147 reference_referent_offset_(0), 148 reference_queue_offset_(0), 149 reference_queueNext_offset_(0), 150 reference_pendingNext_offset_(0), 151 finalizer_reference_zombie_offset_(0), 152 min_free_(min_free), 153 max_free_(max_free), 154 target_utilization_(target_utilization), 155 total_wait_time_(0), 156 total_allocation_time_(0), 157 verify_object_mode_(kVerifyObjectModeDisabled), 158 disable_moving_gc_count_(0), 159 running_on_valgrind_(RUNNING_ON_VALGRIND > 0), 160 use_tlab_(use_tlab) { 161 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 162 LOG(INFO) << "Heap() entering"; 163 } 164 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 165 // entrypoints. 166 if (!Runtime::Current()->IsZygote()) { 167 desired_collector_type_ = post_zygote_collector_type_; 168 large_object_threshold_ = kDefaultLargeObjectThreshold; 169 } else { 170 if (kMovingCollector) { 171 // We are the zygote, use bump pointer allocation + semi space collector. 172 desired_collector_type_ = kCollectorTypeSS; 173 } else { 174 desired_collector_type_ = post_zygote_collector_type_; 175 } 176 } 177 ChangeCollector(desired_collector_type_); 178 179 live_bitmap_.reset(new accounting::HeapBitmap(this)); 180 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 181 // Requested begin for the alloc space, to follow the mapped image and oat files 182 byte* requested_alloc_space_begin = nullptr; 183 if (!image_file_name.empty()) { 184 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 185 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 186 AddSpace(image_space); 187 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 188 // isn't going to get in the middle 189 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 190 CHECK_GT(oat_file_end_addr, image_space->End()); 191 if (oat_file_end_addr > requested_alloc_space_begin) { 192 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 193 } 194 } 195 const char* name = Runtime::Current()->IsZygote() ? "zygote space" : "alloc space"; 196 space::MallocSpace* malloc_space; 197 if (kUseRosAlloc) { 198 malloc_space = space::RosAllocSpace::Create(name, initial_size, growth_limit, capacity, 199 requested_alloc_space_begin, low_memory_mode_); 200 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 201 } else { 202 malloc_space = space::DlMallocSpace::Create(name, initial_size, growth_limit, capacity, 203 requested_alloc_space_begin); 204 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 205 } 206 VLOG(heap) << "malloc_space : " << malloc_space; 207 if (kMovingCollector) { 208 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 209 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 210 // issues. 211 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 212 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 213 bump_pointer_space_size, nullptr); 214 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 215 AddSpace(bump_pointer_space_); 216 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 217 nullptr); 218 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 219 AddSpace(temp_space_); 220 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 221 VLOG(heap) << "temp_space : " << temp_space_; 222 } 223 non_moving_space_ = malloc_space; 224 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 225 AddSpace(malloc_space); 226 227 // Allocate the large object space. 228 constexpr bool kUseFreeListSpaceForLOS = false; 229 if (kUseFreeListSpaceForLOS) { 230 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 231 } else { 232 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 233 } 234 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 235 AddSpace(large_object_space_); 236 237 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 238 CHECK(!continuous_spaces_.empty()); 239 240 // Relies on the spaces being sorted. 241 byte* heap_begin = continuous_spaces_.front()->Begin(); 242 byte* heap_end = continuous_spaces_.back()->Limit(); 243 if (Runtime::Current()->IsZygote()) { 244 std::string error_str; 245 post_zygote_non_moving_space_mem_map_.reset( 246 MemMap::MapAnonymous("post zygote non-moving space", nullptr, 64 * MB, 247 PROT_READ | PROT_WRITE, true, &error_str)); 248 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 249 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 250 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 251 } 252 size_t heap_capacity = heap_end - heap_begin; 253 254 // Allocate the card table. 255 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 256 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 257 258 // Card cache for now since it makes it easier for us to update the references to the copying 259 // spaces. 260 accounting::ModUnionTable* mod_union_table = 261 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 262 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 263 AddModUnionTable(mod_union_table); 264 265 // TODO: Count objects in the image space here. 266 num_bytes_allocated_ = 0; 267 268 // Default mark stack size in bytes. 269 static const size_t default_mark_stack_size = 64 * KB; 270 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 271 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 272 max_allocation_stack_size_)); 273 live_stack_.reset(accounting::ObjectStack::Create("live stack", 274 max_allocation_stack_size_)); 275 276 // It's still too early to take a lock because there are no threads yet, but we can create locks 277 // now. We don't create it earlier to make it clear that you can't use locks during heap 278 // initialization. 279 gc_complete_lock_ = new Mutex("GC complete lock"); 280 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 281 *gc_complete_lock_)); 282 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 283 last_gc_size_ = GetBytesAllocated(); 284 285 if (ignore_max_footprint_) { 286 SetIdealFootprint(std::numeric_limits<size_t>::max()); 287 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 288 } 289 CHECK_NE(max_allowed_footprint_, 0U); 290 291 // Create our garbage collectors. 292 for (size_t i = 0; i < 2; ++i) { 293 const bool concurrent = i != 0; 294 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 295 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 296 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 297 } 298 if (kMovingCollector) { 299 // TODO: Clean this up. 300 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 301 semi_space_collector_ = new collector::SemiSpace(this, generational); 302 garbage_collectors_.push_back(semi_space_collector_); 303 } 304 305 if (running_on_valgrind_) { 306 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 307 } 308 309 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 310 LOG(INFO) << "Heap() exiting"; 311 } 312} 313 314void Heap::ChangeAllocator(AllocatorType allocator) { 315 if (current_allocator_ != allocator) { 316 // These two allocators are only used internally and don't have any entrypoints. 317 CHECK_NE(allocator, kAllocatorTypeLOS); 318 CHECK_NE(allocator, kAllocatorTypeNonMoving); 319 current_allocator_ = allocator; 320 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 321 SetQuickAllocEntryPointsAllocator(current_allocator_); 322 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 323 } 324} 325 326void Heap::DisableCompaction() { 327 if (IsCompactingGC(post_zygote_collector_type_)) { 328 post_zygote_collector_type_ = kCollectorTypeCMS; 329 } 330 if (IsCompactingGC(background_collector_type_)) { 331 background_collector_type_ = post_zygote_collector_type_; 332 } 333 TransitionCollector(post_zygote_collector_type_); 334} 335 336std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 337 if (!IsValidContinuousSpaceObjectAddress(klass)) { 338 return StringPrintf("<non heap address klass %p>", klass); 339 } 340 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 341 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 342 std::string result("["); 343 result += SafeGetClassDescriptor(component_type); 344 return result; 345 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 346 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 347 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 348 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 349 } else { 350 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 351 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 352 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 353 } 354 const DexFile* dex_file = dex_cache->GetDexFile(); 355 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 356 if (class_def_idx == DexFile::kDexNoIndex16) { 357 return "<class def not found>"; 358 } 359 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 360 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 361 return dex_file->GetTypeDescriptor(type_id); 362 } 363} 364 365std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 366 if (obj == nullptr) { 367 return "null"; 368 } 369 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 370 if (klass == nullptr) { 371 return "(class=null)"; 372 } 373 std::string result(SafeGetClassDescriptor(klass)); 374 if (obj->IsClass()) { 375 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 376 } 377 return result; 378} 379 380void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 381 if (obj == nullptr) { 382 stream << "(obj=null)"; 383 return; 384 } 385 if (IsAligned<kObjectAlignment>(obj)) { 386 space::Space* space = nullptr; 387 // Don't use find space since it only finds spaces which actually contain objects instead of 388 // spaces which may contain objects (e.g. cleared bump pointer spaces). 389 for (const auto& cur_space : continuous_spaces_) { 390 if (cur_space->HasAddress(obj)) { 391 space = cur_space; 392 break; 393 } 394 } 395 if (space == nullptr) { 396 if (allocator_mem_map_.get() == nullptr || !allocator_mem_map_->HasAddress(obj)) { 397 stream << "obj " << obj << " not a valid heap address"; 398 return; 399 } else if (allocator_mem_map_.get() != nullptr) { 400 allocator_mem_map_->Protect(PROT_READ | PROT_WRITE); 401 } 402 } 403 // Unprotect all the spaces. 404 for (const auto& space : continuous_spaces_) { 405 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 406 } 407 stream << "Object " << obj; 408 if (space != nullptr) { 409 stream << " in space " << *space; 410 } 411 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 412 stream << "\nclass=" << klass; 413 if (klass != nullptr) { 414 stream << " type= " << SafePrettyTypeOf(obj); 415 } 416 // Re-protect the address we faulted on. 417 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 418 } 419} 420 421bool Heap::IsCompilingBoot() const { 422 for (const auto& space : continuous_spaces_) { 423 if (space->IsImageSpace() || space->IsZygoteSpace()) { 424 return false; 425 } 426 } 427 return true; 428} 429 430bool Heap::HasImageSpace() const { 431 for (const auto& space : continuous_spaces_) { 432 if (space->IsImageSpace()) { 433 return true; 434 } 435 } 436 return false; 437} 438 439void Heap::IncrementDisableMovingGC(Thread* self) { 440 // Need to do this holding the lock to prevent races where the GC is about to run / running when 441 // we attempt to disable it. 442 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 443 MutexLock mu(self, *gc_complete_lock_); 444 ++disable_moving_gc_count_; 445 if (IsCompactingGC(collector_type_running_)) { 446 WaitForGcToCompleteLocked(self); 447 } 448} 449 450void Heap::DecrementDisableMovingGC(Thread* self) { 451 MutexLock mu(self, *gc_complete_lock_); 452 CHECK_GE(disable_moving_gc_count_, 0U); 453 --disable_moving_gc_count_; 454} 455 456void Heap::UpdateProcessState(ProcessState process_state) { 457 if (process_state_ != process_state) { 458 process_state_ = process_state; 459 if (process_state_ == kProcessStateJankPerceptible) { 460 // Transition back to foreground right away to prevent jank. 461 RequestHeapTransition(post_zygote_collector_type_, 0); 462 } else { 463 // Don't delay for debug builds since we may want to stress test the GC. 464 RequestHeapTransition(background_collector_type_, kIsDebugBuild ? 0 : kHeapTransitionWait); 465 } 466 } 467} 468 469void Heap::CreateThreadPool() { 470 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 471 if (num_threads != 0) { 472 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 473 } 474} 475 476void Heap::VisitObjects(ObjectCallback callback, void* arg) { 477 Thread* self = Thread::Current(); 478 // GCs can move objects, so don't allow this. 479 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 480 if (bump_pointer_space_ != nullptr) { 481 // Visit objects in bump pointer space. 482 bump_pointer_space_->Walk(callback, arg); 483 } 484 // TODO: Switch to standard begin and end to use ranged a based loop. 485 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 486 it < end; ++it) { 487 mirror::Object* obj = *it; 488 if (obj != nullptr && obj->GetClass() != nullptr) { 489 // Avoid the race condition caused by the object not yet being written into the allocation 490 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 491 // there can be nulls on the allocation stack. 492 callback(obj, arg); 493 } 494 } 495 GetLiveBitmap()->Walk(callback, arg); 496 self->EndAssertNoThreadSuspension(old_cause); 497} 498 499void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 500 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 501 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 502 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 503 // TODO: Generalize this to n bitmaps? 504 if (space1 == nullptr) { 505 DCHECK(space2 != nullptr); 506 space1 = space2; 507 } 508 if (space2 == nullptr) { 509 DCHECK(space1 != nullptr); 510 space2 = space1; 511 } 512 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 513 large_object_space_->GetLiveObjects(), stack); 514} 515 516void Heap::DeleteThreadPool() { 517 thread_pool_.reset(nullptr); 518} 519 520void Heap::AddSpace(space::Space* space, bool set_as_default) { 521 DCHECK(space != nullptr); 522 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 523 if (space->IsContinuousSpace()) { 524 DCHECK(!space->IsDiscontinuousSpace()); 525 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 526 // Continuous spaces don't necessarily have bitmaps. 527 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 528 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 529 if (live_bitmap != nullptr) { 530 DCHECK(mark_bitmap != nullptr); 531 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 532 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 533 } 534 continuous_spaces_.push_back(continuous_space); 535 if (set_as_default) { 536 if (continuous_space->IsDlMallocSpace()) { 537 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 538 } else if (continuous_space->IsRosAllocSpace()) { 539 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 540 } 541 } 542 // Ensure that spaces remain sorted in increasing order of start address. 543 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 544 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 545 return a->Begin() < b->Begin(); 546 }); 547 } else { 548 DCHECK(space->IsDiscontinuousSpace()); 549 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 550 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 551 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 552 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 553 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 554 discontinuous_spaces_.push_back(discontinuous_space); 555 } 556 if (space->IsAllocSpace()) { 557 alloc_spaces_.push_back(space->AsAllocSpace()); 558 } 559} 560 561void Heap::RemoveSpace(space::Space* space) { 562 DCHECK(space != nullptr); 563 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 564 if (space->IsContinuousSpace()) { 565 DCHECK(!space->IsDiscontinuousSpace()); 566 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 567 // Continuous spaces don't necessarily have bitmaps. 568 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 569 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 570 if (live_bitmap != nullptr) { 571 DCHECK(mark_bitmap != nullptr); 572 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 573 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 574 } 575 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 576 DCHECK(it != continuous_spaces_.end()); 577 continuous_spaces_.erase(it); 578 if (continuous_space == dlmalloc_space_) { 579 dlmalloc_space_ = nullptr; 580 } else if (continuous_space == rosalloc_space_) { 581 rosalloc_space_ = nullptr; 582 } 583 if (continuous_space == main_space_) { 584 main_space_ = nullptr; 585 } 586 } else { 587 DCHECK(space->IsDiscontinuousSpace()); 588 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 589 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 590 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 591 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 592 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 593 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 594 discontinuous_space); 595 DCHECK(it != discontinuous_spaces_.end()); 596 discontinuous_spaces_.erase(it); 597 } 598 if (space->IsAllocSpace()) { 599 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 600 DCHECK(it != alloc_spaces_.end()); 601 alloc_spaces_.erase(it); 602 } 603} 604 605void Heap::RegisterGCAllocation(size_t bytes) { 606 if (this != nullptr) { 607 gc_memory_overhead_.FetchAndAdd(bytes); 608 } 609} 610 611void Heap::RegisterGCDeAllocation(size_t bytes) { 612 if (this != nullptr) { 613 gc_memory_overhead_.FetchAndSub(bytes); 614 } 615} 616 617void Heap::DumpGcPerformanceInfo(std::ostream& os) { 618 // Dump cumulative timings. 619 os << "Dumping cumulative Gc timings\n"; 620 uint64_t total_duration = 0; 621 622 // Dump cumulative loggers for each GC type. 623 uint64_t total_paused_time = 0; 624 for (const auto& collector : garbage_collectors_) { 625 CumulativeLogger& logger = collector->GetCumulativeTimings(); 626 if (logger.GetTotalNs() != 0) { 627 os << Dumpable<CumulativeLogger>(logger); 628 const uint64_t total_ns = logger.GetTotalNs(); 629 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 630 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 631 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 632 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 633 Histogram<uint64_t>::CumulativeData cumulative_data; 634 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 635 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 636 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 637 << collector->GetName() << " freed: " << freed_objects 638 << " objects with total size " << PrettySize(freed_bytes) << "\n" 639 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 640 << PrettySize(freed_bytes / seconds) << "/s\n"; 641 total_duration += total_ns; 642 total_paused_time += total_pause_ns; 643 } 644 } 645 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 646 if (total_duration != 0) { 647 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 648 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 649 os << "Mean GC size throughput: " 650 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 651 os << "Mean GC object throughput: " 652 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 653 } 654 size_t total_objects_allocated = GetObjectsAllocatedEver(); 655 os << "Total number of allocations: " << total_objects_allocated << "\n"; 656 size_t total_bytes_allocated = GetBytesAllocatedEver(); 657 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 658 if (kMeasureAllocationTime) { 659 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 660 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 661 << "\n"; 662 } 663 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 664 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 665 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 666} 667 668Heap::~Heap() { 669 VLOG(heap) << "Starting ~Heap()"; 670 STLDeleteElements(&garbage_collectors_); 671 // If we don't reset then the mark stack complains in its destructor. 672 allocation_stack_->Reset(); 673 live_stack_->Reset(); 674 STLDeleteValues(&mod_union_tables_); 675 STLDeleteElements(&continuous_spaces_); 676 STLDeleteElements(&discontinuous_spaces_); 677 delete gc_complete_lock_; 678 VLOG(heap) << "Finished ~Heap()"; 679} 680 681space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 682 bool fail_ok) const { 683 for (const auto& space : continuous_spaces_) { 684 if (space->Contains(obj)) { 685 return space; 686 } 687 } 688 if (!fail_ok) { 689 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 690 } 691 return NULL; 692} 693 694space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 695 bool fail_ok) const { 696 for (const auto& space : discontinuous_spaces_) { 697 if (space->Contains(obj)) { 698 return space; 699 } 700 } 701 if (!fail_ok) { 702 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 703 } 704 return NULL; 705} 706 707space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 708 space::Space* result = FindContinuousSpaceFromObject(obj, true); 709 if (result != NULL) { 710 return result; 711 } 712 return FindDiscontinuousSpaceFromObject(obj, true); 713} 714 715struct SoftReferenceArgs { 716 IsMarkedCallback* is_marked_callback_; 717 MarkObjectCallback* mark_callback_; 718 void* arg_; 719}; 720 721mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 722 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 723 // TODO: Not preserve all soft references. 724 return args->mark_callback_(obj, args->arg_); 725} 726 727// Process reference class instances and schedule finalizations. 728void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 729 IsMarkedCallback* is_marked_callback, 730 MarkObjectCallback* mark_object_callback, 731 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 732 // Unless we are in the zygote or required to clear soft references with white references, 733 // preserve some white referents. 734 if (!clear_soft && !Runtime::Current()->IsZygote()) { 735 SoftReferenceArgs soft_reference_args; 736 soft_reference_args.is_marked_callback_ = is_marked_callback; 737 soft_reference_args.mark_callback_ = mark_object_callback; 738 soft_reference_args.arg_ = arg; 739 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 740 &soft_reference_args); 741 process_mark_stack_callback(arg); 742 } 743 timings.StartSplit("(Paused)ProcessReferences"); 744 // Clear all remaining soft and weak references with white referents. 745 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 746 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 747 timings.EndSplit(); 748 // Preserve all white objects with finalize methods and schedule them for finalization. 749 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 750 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 751 mark_object_callback, arg); 752 process_mark_stack_callback(arg); 753 timings.EndSplit(); 754 timings.StartSplit("(Paused)ProcessReferences"); 755 // Clear all f-reachable soft and weak references with white referents. 756 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 757 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 758 // Clear all phantom references with white referents. 759 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 760 // At this point all reference queues other than the cleared references should be empty. 761 DCHECK(soft_reference_queue_.IsEmpty()); 762 DCHECK(weak_reference_queue_.IsEmpty()); 763 DCHECK(finalizer_reference_queue_.IsEmpty()); 764 DCHECK(phantom_reference_queue_.IsEmpty()); 765 timings.EndSplit(); 766} 767 768bool Heap::IsEnqueued(mirror::Object* ref) const { 769 // Since the references are stored as cyclic lists it means that once enqueued, the pending next 770 // will always be non-null. 771 return ref->GetFieldObject<mirror::Object>(GetReferencePendingNextOffset(), false) != nullptr; 772} 773 774bool Heap::IsEnqueuable(mirror::Object* ref) const { 775 DCHECK(ref != nullptr); 776 const mirror::Object* queue = 777 ref->GetFieldObject<mirror::Object>(GetReferenceQueueOffset(), false); 778 const mirror::Object* queue_next = 779 ref->GetFieldObject<mirror::Object>(GetReferenceQueueNextOffset(), false); 780 return queue != nullptr && queue_next == nullptr; 781} 782 783// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 784// marked, put it on the appropriate list in the heap for later processing. 785void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Object* obj, 786 IsMarkedCallback is_marked_callback, void* arg) { 787 DCHECK(klass != nullptr); 788 DCHECK(klass->IsReferenceClass()); 789 DCHECK(obj != nullptr); 790 mirror::Object* referent = GetReferenceReferent(obj); 791 if (referent != nullptr) { 792 mirror::Object* forward_address = is_marked_callback(referent, arg); 793 // Null means that the object is not currently marked. 794 if (forward_address == nullptr) { 795 Thread* self = Thread::Current(); 796 // TODO: Remove these locks, and use atomic stacks for storing references? 797 // We need to check that the references haven't already been enqueued since we can end up 798 // scanning the same reference multiple times due to dirty cards. 799 if (klass->IsSoftReferenceClass()) { 800 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 801 } else if (klass->IsWeakReferenceClass()) { 802 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 803 } else if (klass->IsFinalizerReferenceClass()) { 804 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 805 } else if (klass->IsPhantomReferenceClass()) { 806 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, obj); 807 } else { 808 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 809 << klass->GetAccessFlags(); 810 } 811 } else if (referent != forward_address) { 812 // Referent is already marked and we need to update it. 813 SetReferenceReferent(obj, forward_address); 814 } 815 } 816} 817 818space::ImageSpace* Heap::GetImageSpace() const { 819 for (const auto& space : continuous_spaces_) { 820 if (space->IsImageSpace()) { 821 return space->AsImageSpace(); 822 } 823 } 824 return NULL; 825} 826 827static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 828 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 829 if (used_bytes < chunk_size) { 830 size_t chunk_free_bytes = chunk_size - used_bytes; 831 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 832 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 833 } 834} 835 836void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 837 std::ostringstream oss; 838 size_t total_bytes_free = GetFreeMemory(); 839 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 840 << " free bytes"; 841 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 842 if (!large_object_allocation && total_bytes_free >= byte_count) { 843 size_t max_contiguous_allocation = 0; 844 for (const auto& space : continuous_spaces_) { 845 if (space->IsMallocSpace()) { 846 // To allow the Walk/InspectAll() to exclusively-lock the mutator 847 // lock, temporarily release the shared access to the mutator 848 // lock here by transitioning to the suspended state. 849 Locks::mutator_lock_->AssertSharedHeld(self); 850 self->TransitionFromRunnableToSuspended(kSuspended); 851 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 852 self->TransitionFromSuspendedToRunnable(); 853 Locks::mutator_lock_->AssertSharedHeld(self); 854 } 855 } 856 oss << "; failed due to fragmentation (largest possible contiguous allocation " 857 << max_contiguous_allocation << " bytes)"; 858 } 859 self->ThrowOutOfMemoryError(oss.str().c_str()); 860} 861 862void Heap::DoPendingTransitionOrTrim() { 863 Thread* self = Thread::Current(); 864 CollectorType desired_collector_type; 865 // Wait until we reach the desired transition time. 866 while (true) { 867 uint64_t wait_time; 868 { 869 MutexLock mu(self, *heap_trim_request_lock_); 870 desired_collector_type = desired_collector_type_; 871 uint64_t current_time = NanoTime(); 872 if (current_time >= heap_transition_target_time_) { 873 break; 874 } 875 wait_time = heap_transition_target_time_ - current_time; 876 } 877 ScopedThreadStateChange tsc(self, kSleeping); 878 usleep(wait_time / 1000); // Usleep takes microseconds. 879 } 880 // Transition the heap if the desired collector type is nto the same as the current collector type. 881 TransitionCollector(desired_collector_type); 882 // Do a heap trim if it is needed. 883 Trim(); 884} 885 886void Heap::Trim() { 887 Thread* self = Thread::Current(); 888 { 889 MutexLock mu(self, *heap_trim_request_lock_); 890 if (!heap_trim_request_pending_ || NanoTime() < heap_trim_target_time_) { 891 return; 892 } 893 heap_trim_request_pending_ = false; 894 } 895 { 896 // Need to do this before acquiring the locks since we don't want to get suspended while 897 // holding any locks. 898 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 899 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 900 // trimming. 901 MutexLock mu(self, *gc_complete_lock_); 902 // Ensure there is only one GC at a time. 903 WaitForGcToCompleteLocked(self); 904 collector_type_running_ = kCollectorTypeHeapTrim; 905 } 906 uint64_t start_ns = NanoTime(); 907 // Trim the managed spaces. 908 uint64_t total_alloc_space_allocated = 0; 909 uint64_t total_alloc_space_size = 0; 910 uint64_t managed_reclaimed = 0; 911 for (const auto& space : continuous_spaces_) { 912 if (space->IsMallocSpace()) { 913 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 914 total_alloc_space_size += alloc_space->Size(); 915 managed_reclaimed += alloc_space->Trim(); 916 } 917 } 918 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 919 bump_pointer_space_->Size(); 920 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 921 static_cast<float>(total_alloc_space_size); 922 uint64_t gc_heap_end_ns = NanoTime(); 923 // We never move things in the native heap, so we can finish the GC at this point. 924 FinishGC(self, collector::kGcTypeNone); 925 // Trim the native heap. 926 dlmalloc_trim(0); 927 size_t native_reclaimed = 0; 928 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 929 uint64_t end_ns = NanoTime(); 930 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 931 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 932 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 933 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 934 << "%."; 935} 936 937bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 938 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 939 // taking the lock. 940 if (obj == nullptr) { 941 return true; 942 } 943 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 944} 945 946bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 947 return FindContinuousSpaceFromObject(obj, true) != nullptr; 948} 949 950bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 951 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 952 return false; 953 } 954 for (const auto& space : continuous_spaces_) { 955 if (space->HasAddress(obj)) { 956 return true; 957 } 958 } 959 return false; 960} 961 962bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 963 bool search_live_stack, bool sorted) { 964 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 965 return false; 966 } 967 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 968 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 969 if (obj == klass) { 970 // This case happens for java.lang.Class. 971 return true; 972 } 973 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 974 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 975 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 976 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 977 return temp_space_->Contains(obj); 978 } 979 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 980 space::DiscontinuousSpace* d_space = NULL; 981 if (c_space != nullptr) { 982 if (c_space->GetLiveBitmap()->Test(obj)) { 983 return true; 984 } 985 } else { 986 d_space = FindDiscontinuousSpaceFromObject(obj, true); 987 if (d_space != nullptr) { 988 if (d_space->GetLiveObjects()->Test(obj)) { 989 return true; 990 } 991 } 992 } 993 // This is covering the allocation/live stack swapping that is done without mutators suspended. 994 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 995 if (i > 0) { 996 NanoSleep(MsToNs(10)); 997 } 998 if (search_allocation_stack) { 999 if (sorted) { 1000 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1001 return true; 1002 } 1003 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 1004 return true; 1005 } 1006 } 1007 1008 if (search_live_stack) { 1009 if (sorted) { 1010 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1011 return true; 1012 } 1013 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 1014 return true; 1015 } 1016 } 1017 } 1018 // We need to check the bitmaps again since there is a race where we mark something as live and 1019 // then clear the stack containing it. 1020 if (c_space != nullptr) { 1021 if (c_space->GetLiveBitmap()->Test(obj)) { 1022 return true; 1023 } 1024 } else { 1025 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1026 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 1027 return true; 1028 } 1029 } 1030 return false; 1031} 1032 1033void Heap::DumpSpaces(std::ostream& stream) { 1034 for (const auto& space : continuous_spaces_) { 1035 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1036 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1037 stream << space << " " << *space << "\n"; 1038 if (live_bitmap != nullptr) { 1039 stream << live_bitmap << " " << *live_bitmap << "\n"; 1040 } 1041 if (mark_bitmap != nullptr) { 1042 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1043 } 1044 } 1045 for (const auto& space : discontinuous_spaces_) { 1046 stream << space << " " << *space << "\n"; 1047 } 1048} 1049 1050void Heap::VerifyObjectBody(mirror::Object* obj) { 1051 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1052 return; 1053 } 1054 // Ignore early dawn of the universe verifications. 1055 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 1056 return; 1057 } 1058 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1059 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 1060 mirror::Object::ClassOffset(), false); 1061 CHECK(c != nullptr) << "Null class in object " << obj; 1062 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1063 CHECK(VerifyClassClass(c)); 1064 1065 if (verify_object_mode_ > kVerifyObjectModeFast) { 1066 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1067 if (!IsLiveObjectLocked(obj)) { 1068 DumpSpaces(); 1069 LOG(FATAL) << "Object is dead: " << obj; 1070 } 1071 } 1072} 1073 1074void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1075 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1076} 1077 1078void Heap::VerifyHeap() { 1079 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1080 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1081} 1082 1083void Heap::RecordFree(size_t freed_objects, size_t freed_bytes) { 1084 DCHECK_LE(freed_bytes, num_bytes_allocated_.Load()); 1085 num_bytes_allocated_.FetchAndSub(freed_bytes); 1086 if (Runtime::Current()->HasStatsEnabled()) { 1087 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1088 thread_stats->freed_objects += freed_objects; 1089 thread_stats->freed_bytes += freed_bytes; 1090 // TODO: Do this concurrently. 1091 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1092 global_stats->freed_objects += freed_objects; 1093 global_stats->freed_bytes += freed_bytes; 1094 } 1095} 1096 1097mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1098 size_t alloc_size, size_t* bytes_allocated, 1099 size_t* usable_size, 1100 mirror::Class** klass) { 1101 mirror::Object* ptr = nullptr; 1102 bool was_default_allocator = allocator == GetCurrentAllocator(); 1103 DCHECK(klass != nullptr); 1104 SirtRef<mirror::Class> sirt_klass(self, *klass); 1105 // The allocation failed. If the GC is running, block until it completes, and then retry the 1106 // allocation. 1107 collector::GcType last_gc = WaitForGcToComplete(self); 1108 if (last_gc != collector::kGcTypeNone) { 1109 // If we were the default allocator but the allocator changed while we were suspended, 1110 // abort the allocation. 1111 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1112 *klass = sirt_klass.get(); 1113 return nullptr; 1114 } 1115 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1116 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1117 } 1118 1119 // Loop through our different Gc types and try to Gc until we get enough free memory. 1120 for (collector::GcType gc_type : gc_plan_) { 1121 if (ptr != nullptr) { 1122 break; 1123 } 1124 // Attempt to run the collector, if we succeed, re-try the allocation. 1125 bool gc_ran = 1126 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1127 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1128 *klass = sirt_klass.get(); 1129 return nullptr; 1130 } 1131 if (gc_ran) { 1132 // Did we free sufficient memory for the allocation to succeed? 1133 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1134 } 1135 } 1136 // Allocations have failed after GCs; this is an exceptional state. 1137 if (ptr == nullptr) { 1138 // Try harder, growing the heap if necessary. 1139 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1140 } 1141 if (ptr == nullptr) { 1142 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1143 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1144 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1145 // OOME. 1146 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1147 << " allocation"; 1148 // TODO: Run finalization, but this may cause more allocations to occur. 1149 // We don't need a WaitForGcToComplete here either. 1150 DCHECK(!gc_plan_.empty()); 1151 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1152 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1153 *klass = sirt_klass.get(); 1154 return nullptr; 1155 } 1156 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1157 if (ptr == nullptr) { 1158 ThrowOutOfMemoryError(self, alloc_size, false); 1159 } 1160 } 1161 *klass = sirt_klass.get(); 1162 return ptr; 1163} 1164 1165void Heap::SetTargetHeapUtilization(float target) { 1166 DCHECK_GT(target, 0.0f); // asserted in Java code 1167 DCHECK_LT(target, 1.0f); 1168 target_utilization_ = target; 1169} 1170 1171size_t Heap::GetObjectsAllocated() const { 1172 size_t total = 0; 1173 for (space::AllocSpace* space : alloc_spaces_) { 1174 total += space->GetObjectsAllocated(); 1175 } 1176 return total; 1177} 1178 1179size_t Heap::GetObjectsAllocatedEver() const { 1180 return GetObjectsFreedEver() + GetObjectsAllocated(); 1181} 1182 1183size_t Heap::GetBytesAllocatedEver() const { 1184 return GetBytesFreedEver() + GetBytesAllocated(); 1185} 1186 1187class InstanceCounter { 1188 public: 1189 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1190 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1191 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1192 } 1193 static void Callback(mirror::Object* obj, void* arg) 1194 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1195 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1196 mirror::Class* instance_class = obj->GetClass(); 1197 CHECK(instance_class != nullptr); 1198 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1199 if (instance_counter->use_is_assignable_from_) { 1200 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1201 ++instance_counter->counts_[i]; 1202 } 1203 } else if (instance_class == instance_counter->classes_[i]) { 1204 ++instance_counter->counts_[i]; 1205 } 1206 } 1207 } 1208 1209 private: 1210 const std::vector<mirror::Class*>& classes_; 1211 bool use_is_assignable_from_; 1212 uint64_t* const counts_; 1213 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1214}; 1215 1216void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1217 uint64_t* counts) { 1218 // Can't do any GC in this function since this may move classes. 1219 Thread* self = Thread::Current(); 1220 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1221 InstanceCounter counter(classes, use_is_assignable_from, counts); 1222 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1223 VisitObjects(InstanceCounter::Callback, &counter); 1224 self->EndAssertNoThreadSuspension(old_cause); 1225} 1226 1227class InstanceCollector { 1228 public: 1229 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1230 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1231 : class_(c), max_count_(max_count), instances_(instances) { 1232 } 1233 static void Callback(mirror::Object* obj, void* arg) 1234 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1235 DCHECK(arg != nullptr); 1236 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1237 mirror::Class* instance_class = obj->GetClass(); 1238 if (instance_class == instance_collector->class_) { 1239 if (instance_collector->max_count_ == 0 || 1240 instance_collector->instances_.size() < instance_collector->max_count_) { 1241 instance_collector->instances_.push_back(obj); 1242 } 1243 } 1244 } 1245 1246 private: 1247 mirror::Class* class_; 1248 uint32_t max_count_; 1249 std::vector<mirror::Object*>& instances_; 1250 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1251}; 1252 1253void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1254 std::vector<mirror::Object*>& instances) { 1255 // Can't do any GC in this function since this may move classes. 1256 Thread* self = Thread::Current(); 1257 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1258 InstanceCollector collector(c, max_count, instances); 1259 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1260 VisitObjects(&InstanceCollector::Callback, &collector); 1261 self->EndAssertNoThreadSuspension(old_cause); 1262} 1263 1264class ReferringObjectsFinder { 1265 public: 1266 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1267 std::vector<mirror::Object*>& referring_objects) 1268 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1269 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1270 } 1271 1272 static void Callback(mirror::Object* obj, void* arg) 1273 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1274 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1275 } 1276 1277 // For bitmap Visit. 1278 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1279 // annotalysis on visitors. 1280 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1281 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1282 } 1283 1284 // For MarkSweep::VisitObjectReferences. 1285 void operator()(mirror::Object* referrer, mirror::Object* object, 1286 const MemberOffset&, bool) const { 1287 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1288 referring_objects_.push_back(referrer); 1289 } 1290 } 1291 1292 private: 1293 mirror::Object* object_; 1294 uint32_t max_count_; 1295 std::vector<mirror::Object*>& referring_objects_; 1296 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1297}; 1298 1299void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1300 std::vector<mirror::Object*>& referring_objects) { 1301 // Can't do any GC in this function since this may move the object o. 1302 Thread* self = Thread::Current(); 1303 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1304 ReferringObjectsFinder finder(o, max_count, referring_objects); 1305 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1306 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1307 self->EndAssertNoThreadSuspension(old_cause); 1308} 1309 1310void Heap::CollectGarbage(bool clear_soft_references) { 1311 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1312 // last GC will not have necessarily been cleared. 1313 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1314} 1315 1316void Heap::TransitionCollector(CollectorType collector_type) { 1317 if (collector_type == collector_type_) { 1318 return; 1319 } 1320 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1321 << " -> " << static_cast<int>(collector_type); 1322 uint64_t start_time = NanoTime(); 1323 uint32_t before_size = GetTotalMemory(); 1324 uint32_t before_allocated = num_bytes_allocated_.Load(); 1325 ThreadList* tl = Runtime::Current()->GetThreadList(); 1326 Thread* self = Thread::Current(); 1327 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1328 Locks::mutator_lock_->AssertNotHeld(self); 1329 const bool copying_transition = 1330 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1331 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1332 // compacting_gc_disable_count_, this should rarely occurs). 1333 for (;;) { 1334 { 1335 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1336 MutexLock mu(self, *gc_complete_lock_); 1337 // Ensure there is only one GC at a time. 1338 WaitForGcToCompleteLocked(self); 1339 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1340 if (!copying_transition || disable_moving_gc_count_ == 0) { 1341 // TODO: Not hard code in semi-space collector? 1342 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1343 break; 1344 } 1345 } 1346 usleep(1000); 1347 } 1348 tl->SuspendAll(); 1349 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1350 switch (collector_type) { 1351 case kCollectorTypeSS: 1352 // Fall-through. 1353 case kCollectorTypeGSS: { 1354 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1355 CHECK(main_space_ != nullptr); 1356 Compact(temp_space_, main_space_); 1357 DCHECK(allocator_mem_map_.get() == nullptr); 1358 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1359 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1360 // RemoveSpace does not delete the removed space. 1361 space::Space* old_space = main_space_; 1362 RemoveSpace(old_space); 1363 delete old_space; 1364 break; 1365 } 1366 case kCollectorTypeMS: 1367 // Fall through. 1368 case kCollectorTypeCMS: { 1369 if (IsCompactingGC(collector_type_)) { 1370 // TODO: Use mem-map from temp space? 1371 MemMap* mem_map = allocator_mem_map_.release(); 1372 CHECK(mem_map != nullptr); 1373 size_t initial_size = kDefaultInitialSize; 1374 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1375 CHECK(main_space_ == nullptr); 1376 if (kUseRosAlloc) { 1377 main_space_ = 1378 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1379 initial_size, mem_map->Size(), 1380 mem_map->Size(), low_memory_mode_); 1381 } else { 1382 main_space_ = 1383 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", kPageSize, 1384 initial_size, mem_map->Size(), 1385 mem_map->Size()); 1386 } 1387 main_space_->SetFootprintLimit(main_space_->Capacity()); 1388 AddSpace(main_space_); 1389 Compact(main_space_, bump_pointer_space_); 1390 } 1391 break; 1392 } 1393 default: { 1394 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1395 break; 1396 } 1397 } 1398 ChangeCollector(collector_type); 1399 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1400 tl->ResumeAll(); 1401 // Can't call into java code with all threads suspended. 1402 EnqueueClearedReferences(); 1403 uint64_t duration = NanoTime() - start_time; 1404 GrowForUtilization(collector::kGcTypeFull, duration); 1405 FinishGC(self, collector::kGcTypeFull); 1406 int32_t after_size = GetTotalMemory(); 1407 int32_t delta_size = before_size - after_size; 1408 int32_t after_allocated = num_bytes_allocated_.Load(); 1409 int32_t delta_allocated = before_allocated - after_allocated; 1410 const std::string saved_bytes_str = 1411 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1412 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1413 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1414 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1415 << PrettySize(delta_size) << " saved"; 1416} 1417 1418void Heap::ChangeCollector(CollectorType collector_type) { 1419 // TODO: Only do this with all mutators suspended to avoid races. 1420 if (collector_type != collector_type_) { 1421 collector_type_ = collector_type; 1422 gc_plan_.clear(); 1423 switch (collector_type_) { 1424 case kCollectorTypeSS: 1425 // Fall-through. 1426 case kCollectorTypeGSS: { 1427 concurrent_gc_ = false; 1428 gc_plan_.push_back(collector::kGcTypeFull); 1429 if (use_tlab_) { 1430 ChangeAllocator(kAllocatorTypeTLAB); 1431 } else { 1432 ChangeAllocator(kAllocatorTypeBumpPointer); 1433 } 1434 break; 1435 } 1436 case kCollectorTypeMS: { 1437 concurrent_gc_ = false; 1438 gc_plan_.push_back(collector::kGcTypeSticky); 1439 gc_plan_.push_back(collector::kGcTypePartial); 1440 gc_plan_.push_back(collector::kGcTypeFull); 1441 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1442 break; 1443 } 1444 case kCollectorTypeCMS: { 1445 concurrent_gc_ = true; 1446 gc_plan_.push_back(collector::kGcTypeSticky); 1447 gc_plan_.push_back(collector::kGcTypePartial); 1448 gc_plan_.push_back(collector::kGcTypeFull); 1449 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1450 break; 1451 } 1452 default: { 1453 LOG(FATAL) << "Unimplemented"; 1454 } 1455 } 1456 if (concurrent_gc_) { 1457 concurrent_start_bytes_ = 1458 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1459 } else { 1460 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1461 } 1462 } 1463} 1464 1465// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1466class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1467 public: 1468 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, "zygote collector"), 1469 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1470 } 1471 1472 void BuildBins(space::ContinuousSpace* space) { 1473 bin_live_bitmap_ = space->GetLiveBitmap(); 1474 bin_mark_bitmap_ = space->GetMarkBitmap(); 1475 BinContext context; 1476 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1477 context.collector_ = this; 1478 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1479 // Note: This requires traversing the space in increasing order of object addresses. 1480 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1481 // Add the last bin which spans after the last object to the end of the space. 1482 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1483 } 1484 1485 private: 1486 struct BinContext { 1487 uintptr_t prev_; // The end of the previous object. 1488 ZygoteCompactingCollector* collector_; 1489 }; 1490 // Maps from bin sizes to locations. 1491 std::multimap<size_t, uintptr_t> bins_; 1492 // Live bitmap of the space which contains the bins. 1493 accounting::SpaceBitmap* bin_live_bitmap_; 1494 // Mark bitmap of the space which contains the bins. 1495 accounting::SpaceBitmap* bin_mark_bitmap_; 1496 1497 static void Callback(mirror::Object* obj, void* arg) 1498 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1499 DCHECK(arg != nullptr); 1500 BinContext* context = reinterpret_cast<BinContext*>(arg); 1501 ZygoteCompactingCollector* collector = context->collector_; 1502 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1503 size_t bin_size = object_addr - context->prev_; 1504 // Add the bin consisting of the end of the previous object to the start of the current object. 1505 collector->AddBin(bin_size, context->prev_); 1506 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1507 } 1508 1509 void AddBin(size_t size, uintptr_t position) { 1510 if (size != 0) { 1511 bins_.insert(std::make_pair(size, position)); 1512 } 1513 } 1514 1515 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1516 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1517 // allocator. 1518 return false; 1519 } 1520 1521 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1522 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1523 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1524 mirror::Object* forward_address; 1525 // Find the smallest bin which we can move obj in. 1526 auto it = bins_.lower_bound(object_size); 1527 if (it == bins_.end()) { 1528 // No available space in the bins, place it in the target space instead (grows the zygote 1529 // space). 1530 size_t bytes_allocated; 1531 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1532 if (to_space_live_bitmap_ != nullptr) { 1533 to_space_live_bitmap_->Set(forward_address); 1534 } else { 1535 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1536 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1537 } 1538 } else { 1539 size_t size = it->first; 1540 uintptr_t pos = it->second; 1541 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1542 forward_address = reinterpret_cast<mirror::Object*>(pos); 1543 // Set the live and mark bits so that sweeping system weaks works properly. 1544 bin_live_bitmap_->Set(forward_address); 1545 bin_mark_bitmap_->Set(forward_address); 1546 DCHECK_GE(size, object_size); 1547 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1548 } 1549 // Copy the object over to its new location. 1550 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1551 if (kUseBrooksPointer) { 1552 obj->AssertSelfBrooksPointer(); 1553 DCHECK_EQ(forward_address->GetBrooksPointer(), obj); 1554 forward_address->SetBrooksPointer(forward_address); 1555 forward_address->AssertSelfBrooksPointer(); 1556 } 1557 return forward_address; 1558 } 1559}; 1560 1561void Heap::UnBindBitmaps() { 1562 for (const auto& space : GetContinuousSpaces()) { 1563 if (space->IsContinuousMemMapAllocSpace()) { 1564 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1565 if (alloc_space->HasBoundBitmaps()) { 1566 alloc_space->UnBindBitmaps(); 1567 } 1568 } 1569 } 1570} 1571 1572void Heap::PreZygoteFork() { 1573 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1574 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1575 Thread* self = Thread::Current(); 1576 MutexLock mu(self, zygote_creation_lock_); 1577 // Try to see if we have any Zygote spaces. 1578 if (have_zygote_space_) { 1579 return; 1580 } 1581 VLOG(heap) << "Starting PreZygoteFork"; 1582 // Trim the pages at the end of the non moving space. 1583 non_moving_space_->Trim(); 1584 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1585 // Change the collector to the post zygote one. 1586 ChangeCollector(post_zygote_collector_type_); 1587 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1588 if (semi_space_collector_ != nullptr) { 1589 // Temporarily disable rosalloc verification because the zygote 1590 // compaction will mess up the rosalloc internal metadata. 1591 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1592 ZygoteCompactingCollector zygote_collector(this); 1593 zygote_collector.BuildBins(non_moving_space_); 1594 // Create a new bump pointer space which we will compact into. 1595 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1596 non_moving_space_->Limit()); 1597 // Compact the bump pointer space to a new zygote bump pointer space. 1598 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1599 zygote_collector.SetFromSpace(bump_pointer_space_); 1600 zygote_collector.SetToSpace(&target_space); 1601 zygote_collector.Run(kGcCauseCollectorTransition, false); 1602 CHECK(temp_space_->IsEmpty()); 1603 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1604 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1605 // Update the end and write out image. 1606 non_moving_space_->SetEnd(target_space.End()); 1607 non_moving_space_->SetLimit(target_space.Limit()); 1608 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1609 } 1610 // Save the old space so that we can remove it after we complete creating the zygote space. 1611 space::MallocSpace* old_alloc_space = non_moving_space_; 1612 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1613 // the remaining available space. 1614 // Remove the old space before creating the zygote space since creating the zygote space sets 1615 // the old alloc space's bitmaps to nullptr. 1616 RemoveSpace(old_alloc_space); 1617 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1618 low_memory_mode_, 1619 &main_space_); 1620 delete old_alloc_space; 1621 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1622 AddSpace(zygote_space, false); 1623 CHECK(main_space_ != nullptr); 1624 if (main_space_->IsRosAllocSpace()) { 1625 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1626 } else if (main_space_->IsDlMallocSpace()) { 1627 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1628 } 1629 main_space_->SetFootprintLimit(main_space_->Capacity()); 1630 AddSpace(main_space_); 1631 have_zygote_space_ = true; 1632 // Enable large object space allocations. 1633 large_object_threshold_ = kDefaultLargeObjectThreshold; 1634 // Create the zygote space mod union table. 1635 accounting::ModUnionTable* mod_union_table = 1636 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1637 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1638 AddModUnionTable(mod_union_table); 1639 // Can't use RosAlloc for non moving space due to thread local buffers. 1640 // TODO: Non limited space for non-movable objects? 1641 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1642 space::MallocSpace* new_non_moving_space = 1643 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1644 2 * MB, mem_map->Size(), mem_map->Size()); 1645 AddSpace(new_non_moving_space, false); 1646 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1647 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1648 non_moving_space_ = new_non_moving_space; 1649} 1650 1651void Heap::FlushAllocStack() { 1652 MarkAllocStackAsLive(allocation_stack_.get()); 1653 allocation_stack_->Reset(); 1654} 1655 1656void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1657 accounting::SpaceBitmap* bitmap2, 1658 accounting::ObjectSet* large_objects, 1659 accounting::ObjectStack* stack) { 1660 DCHECK(bitmap1 != nullptr); 1661 DCHECK(bitmap2 != nullptr); 1662 mirror::Object** limit = stack->End(); 1663 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1664 const mirror::Object* obj = *it; 1665 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1666 if (bitmap1->HasAddress(obj)) { 1667 bitmap1->Set(obj); 1668 } else if (bitmap2->HasAddress(obj)) { 1669 bitmap2->Set(obj); 1670 } else { 1671 large_objects->Set(obj); 1672 } 1673 } 1674 } 1675} 1676 1677void Heap::SwapSemiSpaces() { 1678 // Swap the spaces so we allocate into the space which we just evacuated. 1679 std::swap(bump_pointer_space_, temp_space_); 1680 bump_pointer_space_->Clear(); 1681} 1682 1683void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1684 space::ContinuousMemMapAllocSpace* source_space) { 1685 CHECK(kMovingCollector); 1686 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1687 if (target_space != source_space) { 1688 semi_space_collector_->SetFromSpace(source_space); 1689 semi_space_collector_->SetToSpace(target_space); 1690 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1691 } 1692} 1693 1694collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1695 bool clear_soft_references) { 1696 Thread* self = Thread::Current(); 1697 Runtime* runtime = Runtime::Current(); 1698 // If the heap can't run the GC, silently fail and return that no GC was run. 1699 switch (gc_type) { 1700 case collector::kGcTypePartial: { 1701 if (!have_zygote_space_) { 1702 return collector::kGcTypeNone; 1703 } 1704 break; 1705 } 1706 default: { 1707 // Other GC types don't have any special cases which makes them not runnable. The main case 1708 // here is full GC. 1709 } 1710 } 1711 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1712 Locks::mutator_lock_->AssertNotHeld(self); 1713 if (self->IsHandlingStackOverflow()) { 1714 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1715 } 1716 bool compacting_gc; 1717 { 1718 gc_complete_lock_->AssertNotHeld(self); 1719 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1720 MutexLock mu(self, *gc_complete_lock_); 1721 // Ensure there is only one GC at a time. 1722 WaitForGcToCompleteLocked(self); 1723 compacting_gc = IsCompactingGC(collector_type_); 1724 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1725 if (compacting_gc && disable_moving_gc_count_ != 0) { 1726 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1727 return collector::kGcTypeNone; 1728 } 1729 collector_type_running_ = collector_type_; 1730 } 1731 1732 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1733 ++runtime->GetStats()->gc_for_alloc_count; 1734 ++self->GetStats()->gc_for_alloc_count; 1735 } 1736 uint64_t gc_start_time_ns = NanoTime(); 1737 uint64_t gc_start_size = GetBytesAllocated(); 1738 // Approximate allocation rate in bytes / second. 1739 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1740 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1741 if (LIKELY(ms_delta != 0)) { 1742 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1743 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1744 } 1745 1746 DCHECK_LT(gc_type, collector::kGcTypeMax); 1747 DCHECK_NE(gc_type, collector::kGcTypeNone); 1748 1749 collector::GarbageCollector* collector = nullptr; 1750 // TODO: Clean this up. 1751 if (compacting_gc) { 1752 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1753 current_allocator_ == kAllocatorTypeTLAB); 1754 gc_type = semi_space_collector_->GetGcType(); 1755 CHECK(temp_space_->IsEmpty()); 1756 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1757 semi_space_collector_->SetToSpace(temp_space_); 1758 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1759 collector = semi_space_collector_; 1760 gc_type = collector::kGcTypeFull; 1761 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1762 current_allocator_ == kAllocatorTypeDlMalloc) { 1763 for (const auto& cur_collector : garbage_collectors_) { 1764 if (cur_collector->IsConcurrent() == concurrent_gc_ && 1765 cur_collector->GetGcType() == gc_type) { 1766 collector = cur_collector; 1767 break; 1768 } 1769 } 1770 } else { 1771 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1772 } 1773 CHECK(collector != nullptr) 1774 << "Could not find garbage collector with concurrent=" << concurrent_gc_ 1775 << " and type=" << gc_type; 1776 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1777 collector->Run(gc_cause, clear_soft_references); 1778 total_objects_freed_ever_ += collector->GetFreedObjects(); 1779 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1780 RequestHeapTrim(Heap::kHeapTrimWait); 1781 // Enqueue cleared references. 1782 EnqueueClearedReferences(); 1783 // Grow the heap so that we know when to perform the next GC. 1784 GrowForUtilization(gc_type, collector->GetDurationNs()); 1785 if (CareAboutPauseTimes()) { 1786 const size_t duration = collector->GetDurationNs(); 1787 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1788 // GC for alloc pauses the allocating thread, so consider it as a pause. 1789 bool was_slow = duration > long_gc_log_threshold_ || 1790 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1791 if (!was_slow) { 1792 for (uint64_t pause : pauses) { 1793 was_slow = was_slow || pause > long_pause_log_threshold_; 1794 } 1795 } 1796 if (was_slow) { 1797 const size_t percent_free = GetPercentFree(); 1798 const size_t current_heap_size = GetBytesAllocated(); 1799 const size_t total_memory = GetTotalMemory(); 1800 std::ostringstream pause_string; 1801 for (size_t i = 0; i < pauses.size(); ++i) { 1802 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1803 << ((i != pauses.size() - 1) ? ", " : ""); 1804 } 1805 LOG(INFO) << gc_cause << " " << collector->GetName() 1806 << " GC freed " << collector->GetFreedObjects() << "(" 1807 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1808 << collector->GetFreedLargeObjects() << "(" 1809 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1810 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1811 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1812 << " total " << PrettyDuration((duration / 1000) * 1000); 1813 if (VLOG_IS_ON(heap)) { 1814 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1815 } 1816 } 1817 } 1818 FinishGC(self, gc_type); 1819 ATRACE_END(); 1820 1821 // Inform DDMS that a GC completed. 1822 Dbg::GcDidFinish(); 1823 return gc_type; 1824} 1825 1826void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1827 MutexLock mu(self, *gc_complete_lock_); 1828 collector_type_running_ = kCollectorTypeNone; 1829 if (gc_type != collector::kGcTypeNone) { 1830 last_gc_type_ = gc_type; 1831 } 1832 // Wake anyone who may have been waiting for the GC to complete. 1833 gc_complete_cond_->Broadcast(self); 1834} 1835 1836static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1837 RootType /*root_type*/) { 1838 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1839 if (*root == obj) { 1840 LOG(INFO) << "Object " << obj << " is a root"; 1841 } 1842} 1843 1844class ScanVisitor { 1845 public: 1846 void operator()(const mirror::Object* obj) const { 1847 LOG(ERROR) << "Would have rescanned object " << obj; 1848 } 1849}; 1850 1851// Verify a reference from an object. 1852class VerifyReferenceVisitor { 1853 public: 1854 explicit VerifyReferenceVisitor(Heap* heap) 1855 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1856 : heap_(heap), failed_(false) {} 1857 1858 bool Failed() const { 1859 return failed_; 1860 } 1861 1862 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1863 // analysis on visitors. 1864 void operator()(mirror::Object* obj, mirror::Object* ref, 1865 const MemberOffset& offset, bool /* is_static */) const 1866 NO_THREAD_SAFETY_ANALYSIS { 1867 if (ref == nullptr || IsLive(ref)) { 1868 // Verify that the reference is live. 1869 return; 1870 } 1871 if (!failed_) { 1872 // Print message on only on first failure to prevent spam. 1873 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1874 failed_ = true; 1875 } 1876 if (obj != nullptr) { 1877 accounting::CardTable* card_table = heap_->GetCardTable(); 1878 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1879 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1880 byte* card_addr = card_table->CardFromAddr(obj); 1881 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1882 << offset << "\n card value = " << static_cast<int>(*card_addr); 1883 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1884 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1885 } else { 1886 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1887 } 1888 1889 // Attmept to find the class inside of the recently freed objects. 1890 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1891 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1892 space::MallocSpace* space = ref_space->AsMallocSpace(); 1893 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1894 if (ref_class != nullptr) { 1895 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1896 << PrettyClass(ref_class); 1897 } else { 1898 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1899 } 1900 } 1901 1902 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1903 ref->GetClass()->IsClass()) { 1904 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1905 } else { 1906 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1907 << ") is not a valid heap address"; 1908 } 1909 1910 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1911 void* cover_begin = card_table->AddrFromCard(card_addr); 1912 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1913 accounting::CardTable::kCardSize); 1914 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1915 << "-" << cover_end; 1916 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1917 1918 if (bitmap == nullptr) { 1919 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1920 if (!VerifyClassClass(obj->GetClass())) { 1921 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1922 } 1923 } else { 1924 // Print out how the object is live. 1925 if (bitmap->Test(obj)) { 1926 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1927 } 1928 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1929 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1930 } 1931 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1932 LOG(ERROR) << "Object " << obj << " found in live stack"; 1933 } 1934 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1935 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1936 } 1937 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1938 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1939 } 1940 // Attempt to see if the card table missed the reference. 1941 ScanVisitor scan_visitor; 1942 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1943 card_table->Scan(bitmap, byte_cover_begin, 1944 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1945 } 1946 1947 // Search to see if any of the roots reference our object. 1948 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1949 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 1950 1951 // Search to see if any of the roots reference our reference. 1952 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 1953 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 1954 } else { 1955 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 1956 } 1957 } 1958 1959 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 1960 return heap_->IsLiveObjectLocked(obj, true, false, true); 1961 } 1962 1963 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1964 RootType /*root_type*/) { 1965 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 1966 (*visitor)(nullptr, *root, MemberOffset(0), true); 1967 } 1968 1969 private: 1970 Heap* const heap_; 1971 mutable bool failed_; 1972}; 1973 1974// Verify all references within an object, for use with HeapBitmap::Visit. 1975class VerifyObjectVisitor { 1976 public: 1977 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 1978 1979 void operator()(mirror::Object* obj) const 1980 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1981 // Note: we are verifying the references in obj but not obj itself, this is because obj must 1982 // be live or else how did we find it in the live bitmap? 1983 VerifyReferenceVisitor visitor(heap_); 1984 // The class doesn't count as a reference but we should verify it anyways. 1985 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 1986 if (obj->GetClass()->IsReferenceClass()) { 1987 visitor(obj, heap_->GetReferenceReferent(obj), MemberOffset(0), false); 1988 } 1989 failed_ = failed_ || visitor.Failed(); 1990 } 1991 1992 static void VisitCallback(mirror::Object* obj, void* arg) 1993 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1994 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 1995 visitor->operator()(obj); 1996 } 1997 1998 bool Failed() const { 1999 return failed_; 2000 } 2001 2002 private: 2003 Heap* const heap_; 2004 mutable bool failed_; 2005}; 2006 2007// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2008bool Heap::VerifyHeapReferences() { 2009 Thread* self = Thread::Current(); 2010 Locks::mutator_lock_->AssertExclusiveHeld(self); 2011 // Lets sort our allocation stacks so that we can efficiently binary search them. 2012 allocation_stack_->Sort(); 2013 live_stack_->Sort(); 2014 // Since we sorted the allocation stack content, need to revoke all 2015 // thread-local allocation stacks. 2016 RevokeAllThreadLocalAllocationStacks(self); 2017 VerifyObjectVisitor visitor(this); 2018 // Verify objects in the allocation stack since these will be objects which were: 2019 // 1. Allocated prior to the GC (pre GC verification). 2020 // 2. Allocated during the GC (pre sweep GC verification). 2021 // We don't want to verify the objects in the live stack since they themselves may be 2022 // pointing to dead objects if they are not reachable. 2023 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2024 // Verify the roots: 2025 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor); 2026 if (visitor.Failed()) { 2027 // Dump mod-union tables. 2028 for (const auto& table_pair : mod_union_tables_) { 2029 accounting::ModUnionTable* mod_union_table = table_pair.second; 2030 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2031 } 2032 DumpSpaces(); 2033 return false; 2034 } 2035 return true; 2036} 2037 2038class VerifyReferenceCardVisitor { 2039 public: 2040 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2041 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2042 Locks::heap_bitmap_lock_) 2043 : heap_(heap), failed_(failed) { 2044 } 2045 2046 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2047 // annotalysis on visitors. 2048 void operator()(mirror::Object* obj, mirror::Object* ref, const MemberOffset& offset, 2049 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 2050 // Filter out class references since changing an object's class does not mark the card as dirty. 2051 // Also handles large objects, since the only reference they hold is a class reference. 2052 if (ref != NULL && !ref->IsClass()) { 2053 accounting::CardTable* card_table = heap_->GetCardTable(); 2054 // If the object is not dirty and it is referencing something in the live stack other than 2055 // class, then it must be on a dirty card. 2056 if (!card_table->AddrIsInCardTable(obj)) { 2057 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2058 *failed_ = true; 2059 } else if (!card_table->IsDirty(obj)) { 2060 // TODO: Check mod-union tables. 2061 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2062 // kCardDirty - 1 if it didnt get touched since we aged it. 2063 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2064 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 2065 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 2066 LOG(ERROR) << "Object " << obj << " found in live stack"; 2067 } 2068 if (heap_->GetLiveBitmap()->Test(obj)) { 2069 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2070 } 2071 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2072 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2073 2074 // Print which field of the object is dead. 2075 if (!obj->IsObjectArray()) { 2076 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2077 CHECK(klass != NULL); 2078 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2079 : klass->GetIFields(); 2080 CHECK(fields != NULL); 2081 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2082 mirror::ArtField* cur = fields->Get(i); 2083 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2084 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2085 << PrettyField(cur); 2086 break; 2087 } 2088 } 2089 } else { 2090 mirror::ObjectArray<mirror::Object>* object_array = 2091 obj->AsObjectArray<mirror::Object>(); 2092 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2093 if (object_array->Get(i) == ref) { 2094 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2095 } 2096 } 2097 } 2098 2099 *failed_ = true; 2100 } 2101 } 2102 } 2103 } 2104 2105 private: 2106 Heap* const heap_; 2107 bool* const failed_; 2108}; 2109 2110class VerifyLiveStackReferences { 2111 public: 2112 explicit VerifyLiveStackReferences(Heap* heap) 2113 : heap_(heap), 2114 failed_(false) {} 2115 2116 void operator()(mirror::Object* obj) const 2117 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2118 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2119 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 2120 } 2121 2122 bool Failed() const { 2123 return failed_; 2124 } 2125 2126 private: 2127 Heap* const heap_; 2128 bool failed_; 2129}; 2130 2131bool Heap::VerifyMissingCardMarks() { 2132 Thread* self = Thread::Current(); 2133 Locks::mutator_lock_->AssertExclusiveHeld(self); 2134 2135 // We need to sort the live stack since we binary search it. 2136 live_stack_->Sort(); 2137 // Since we sorted the allocation stack content, need to revoke all 2138 // thread-local allocation stacks. 2139 RevokeAllThreadLocalAllocationStacks(self); 2140 VerifyLiveStackReferences visitor(this); 2141 GetLiveBitmap()->Visit(visitor); 2142 2143 // We can verify objects in the live stack since none of these should reference dead objects. 2144 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2145 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2146 visitor(*it); 2147 } 2148 } 2149 2150 if (visitor.Failed()) { 2151 DumpSpaces(); 2152 return false; 2153 } 2154 return true; 2155} 2156 2157void Heap::SwapStacks(Thread* self) { 2158 if (kUseThreadLocalAllocationStack) { 2159 live_stack_->AssertAllZero(); 2160 } 2161 allocation_stack_.swap(live_stack_); 2162} 2163 2164void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2165 // This must be called only during the pause. 2166 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2167 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2168 MutexLock mu2(self, *Locks::thread_list_lock_); 2169 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2170 for (Thread* t : thread_list) { 2171 t->RevokeThreadLocalAllocationStack(); 2172 } 2173} 2174 2175accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2176 auto it = mod_union_tables_.find(space); 2177 if (it == mod_union_tables_.end()) { 2178 return nullptr; 2179 } 2180 return it->second; 2181} 2182 2183void Heap::ProcessCards(TimingLogger& timings) { 2184 // Clear cards and keep track of cards cleared in the mod-union table. 2185 for (const auto& space : continuous_spaces_) { 2186 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2187 if (table != nullptr) { 2188 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2189 "ImageModUnionClearCards"; 2190 TimingLogger::ScopedSplit split(name, &timings); 2191 table->ClearCards(); 2192 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2193 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2194 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2195 // were dirty before the GC started. 2196 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2197 // -> clean(cleaning thread). 2198 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2199 // roots and then we scan / update mod union tables after. We will always scan either card. 2200 // If we end up with the non aged card, we scan it it in the pause. 2201 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2202 } 2203 } 2204} 2205 2206static mirror::Object* IdentityMarkObjectCallback(mirror::Object* obj, void*) { 2207 return obj; 2208} 2209 2210void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2211 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2212 Thread* self = Thread::Current(); 2213 2214 if (verify_pre_gc_heap_) { 2215 thread_list->SuspendAll(); 2216 { 2217 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2218 if (!VerifyHeapReferences()) { 2219 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2220 } 2221 } 2222 thread_list->ResumeAll(); 2223 } 2224 2225 // Check that all objects which reference things in the live stack are on dirty cards. 2226 if (verify_missing_card_marks_) { 2227 thread_list->SuspendAll(); 2228 { 2229 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2230 SwapStacks(self); 2231 // Sort the live stack so that we can quickly binary search it later. 2232 if (!VerifyMissingCardMarks()) { 2233 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2234 } 2235 SwapStacks(self); 2236 } 2237 thread_list->ResumeAll(); 2238 } 2239 2240 if (verify_mod_union_table_) { 2241 thread_list->SuspendAll(); 2242 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2243 for (const auto& table_pair : mod_union_tables_) { 2244 accounting::ModUnionTable* mod_union_table = table_pair.second; 2245 mod_union_table->UpdateAndMarkReferences(IdentityMarkObjectCallback, nullptr); 2246 mod_union_table->Verify(); 2247 } 2248 thread_list->ResumeAll(); 2249 } 2250} 2251 2252void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2253 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2254 // reachable objects. 2255 if (verify_post_gc_heap_) { 2256 Thread* self = Thread::Current(); 2257 CHECK_NE(self->GetState(), kRunnable); 2258 { 2259 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2260 // Swapping bound bitmaps does nothing. 2261 gc->SwapBitmaps(); 2262 if (!VerifyHeapReferences()) { 2263 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2264 } 2265 gc->SwapBitmaps(); 2266 } 2267 } 2268} 2269 2270void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2271 if (verify_system_weaks_) { 2272 Thread* self = Thread::Current(); 2273 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2274 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2275 mark_sweep->VerifySystemWeaks(); 2276 } 2277} 2278 2279void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2280 if (verify_pre_gc_rosalloc_) { 2281 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2282 for (const auto& space : continuous_spaces_) { 2283 if (space->IsRosAllocSpace()) { 2284 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2285 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2286 rosalloc_space->Verify(); 2287 } 2288 } 2289 } 2290} 2291 2292void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2293 if (verify_post_gc_rosalloc_) { 2294 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2295 for (const auto& space : continuous_spaces_) { 2296 if (space->IsRosAllocSpace()) { 2297 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2298 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2299 rosalloc_space->Verify(); 2300 } 2301 } 2302 } 2303} 2304 2305collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2306 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2307 MutexLock mu(self, *gc_complete_lock_); 2308 return WaitForGcToCompleteLocked(self); 2309} 2310 2311collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2312 collector::GcType last_gc_type = collector::kGcTypeNone; 2313 uint64_t wait_start = NanoTime(); 2314 while (collector_type_running_ != kCollectorTypeNone) { 2315 ATRACE_BEGIN("GC: Wait For Completion"); 2316 // We must wait, change thread state then sleep on gc_complete_cond_; 2317 gc_complete_cond_->Wait(self); 2318 last_gc_type = last_gc_type_; 2319 ATRACE_END(); 2320 } 2321 uint64_t wait_time = NanoTime() - wait_start; 2322 total_wait_time_ += wait_time; 2323 if (wait_time > long_pause_log_threshold_) { 2324 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2325 } 2326 return last_gc_type; 2327} 2328 2329void Heap::DumpForSigQuit(std::ostream& os) { 2330 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2331 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2332 DumpGcPerformanceInfo(os); 2333} 2334 2335size_t Heap::GetPercentFree() { 2336 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2337} 2338 2339void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2340 if (max_allowed_footprint > GetMaxMemory()) { 2341 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2342 << PrettySize(GetMaxMemory()); 2343 max_allowed_footprint = GetMaxMemory(); 2344 } 2345 max_allowed_footprint_ = max_allowed_footprint; 2346} 2347 2348bool Heap::IsMovableObject(const mirror::Object* obj) const { 2349 if (kMovingCollector) { 2350 DCHECK(!IsInTempSpace(obj)); 2351 if (bump_pointer_space_->HasAddress(obj)) { 2352 return true; 2353 } 2354 // TODO: Refactor this logic into the space itself? 2355 // Objects in the main space are only copied during background -> foreground transitions or 2356 // visa versa. 2357 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2358 (IsCompactingGC(background_collector_type_) || 2359 IsCompactingGC(post_zygote_collector_type_))) { 2360 return true; 2361 } 2362 } 2363 return false; 2364} 2365 2366bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2367 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2368 return true; 2369 } 2370 return false; 2371} 2372 2373void Heap::UpdateMaxNativeFootprint() { 2374 size_t native_size = native_bytes_allocated_; 2375 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2376 size_t target_size = native_size / GetTargetHeapUtilization(); 2377 if (target_size > native_size + max_free_) { 2378 target_size = native_size + max_free_; 2379 } else if (target_size < native_size + min_free_) { 2380 target_size = native_size + min_free_; 2381 } 2382 native_footprint_gc_watermark_ = target_size; 2383 native_footprint_limit_ = 2 * target_size - native_size; 2384} 2385 2386void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2387 // We know what our utilization is at this moment. 2388 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2389 const size_t bytes_allocated = GetBytesAllocated(); 2390 last_gc_size_ = bytes_allocated; 2391 last_gc_time_ns_ = NanoTime(); 2392 size_t target_size; 2393 if (gc_type != collector::kGcTypeSticky) { 2394 // Grow the heap for non sticky GC. 2395 target_size = bytes_allocated / GetTargetHeapUtilization(); 2396 if (target_size > bytes_allocated + max_free_) { 2397 target_size = bytes_allocated + max_free_; 2398 } else if (target_size < bytes_allocated + min_free_) { 2399 target_size = bytes_allocated + min_free_; 2400 } 2401 native_need_to_run_finalization_ = true; 2402 next_gc_type_ = collector::kGcTypeSticky; 2403 } else { 2404 // Based on how close the current heap size is to the target size, decide 2405 // whether or not to do a partial or sticky GC next. 2406 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2407 next_gc_type_ = collector::kGcTypeSticky; 2408 } else { 2409 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2410 } 2411 // If we have freed enough memory, shrink the heap back down. 2412 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2413 target_size = bytes_allocated + max_free_; 2414 } else { 2415 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2416 } 2417 } 2418 if (!ignore_max_footprint_) { 2419 SetIdealFootprint(target_size); 2420 if (concurrent_gc_) { 2421 // Calculate when to perform the next ConcurrentGC. 2422 // Calculate the estimated GC duration. 2423 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2424 // Estimate how many remaining bytes we will have when we need to start the next GC. 2425 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2426 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2427 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2428 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2429 // A never going to happen situation that from the estimated allocation rate we will exceed 2430 // the applications entire footprint with the given estimated allocation rate. Schedule 2431 // another GC nearly straight away. 2432 remaining_bytes = kMinConcurrentRemainingBytes; 2433 } 2434 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2435 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2436 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2437 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2438 // right away. 2439 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2440 } 2441 } 2442} 2443 2444void Heap::ClearGrowthLimit() { 2445 growth_limit_ = capacity_; 2446 non_moving_space_->ClearGrowthLimit(); 2447} 2448 2449void Heap::SetReferenceOffsets(MemberOffset reference_referent_offset, 2450 MemberOffset reference_queue_offset, 2451 MemberOffset reference_queueNext_offset, 2452 MemberOffset reference_pendingNext_offset, 2453 MemberOffset finalizer_reference_zombie_offset) { 2454 reference_referent_offset_ = reference_referent_offset; 2455 reference_queue_offset_ = reference_queue_offset; 2456 reference_queueNext_offset_ = reference_queueNext_offset; 2457 reference_pendingNext_offset_ = reference_pendingNext_offset; 2458 finalizer_reference_zombie_offset_ = finalizer_reference_zombie_offset; 2459 CHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2460 CHECK_NE(reference_queue_offset_.Uint32Value(), 0U); 2461 CHECK_NE(reference_queueNext_offset_.Uint32Value(), 0U); 2462 CHECK_NE(reference_pendingNext_offset_.Uint32Value(), 0U); 2463 CHECK_NE(finalizer_reference_zombie_offset_.Uint32Value(), 0U); 2464} 2465 2466void Heap::SetReferenceReferent(mirror::Object* reference, mirror::Object* referent) { 2467 DCHECK(reference != NULL); 2468 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2469 reference->SetFieldObject<false, false>(reference_referent_offset_, referent, true); 2470} 2471 2472mirror::Object* Heap::GetReferenceReferent(mirror::Object* reference) { 2473 DCHECK(reference != NULL); 2474 DCHECK_NE(reference_referent_offset_.Uint32Value(), 0U); 2475 return reference->GetFieldObject<mirror::Object>(reference_referent_offset_, true); 2476} 2477 2478void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2479 ScopedObjectAccess soa(self); 2480 JValue result; 2481 ArgArray arg_array("VL", 2); 2482 arg_array.Append(object); 2483 soa.DecodeMethod(WellKnownClasses::java_lang_ref_FinalizerReference_add)->Invoke(self, 2484 arg_array.GetArray(), arg_array.GetNumBytes(), &result, "VL"); 2485} 2486 2487void Heap::EnqueueClearedReferences() { 2488 Thread* self = Thread::Current(); 2489 Locks::mutator_lock_->AssertNotHeld(self); 2490 if (!cleared_references_.IsEmpty()) { 2491 // When a runtime isn't started there are no reference queues to care about so ignore. 2492 if (LIKELY(Runtime::Current()->IsStarted())) { 2493 ScopedObjectAccess soa(self); 2494 JValue result; 2495 ArgArray arg_array("VL", 2); 2496 arg_array.Append(cleared_references_.GetList()); 2497 soa.DecodeMethod(WellKnownClasses::java_lang_ref_ReferenceQueue_add)->Invoke(soa.Self(), 2498 arg_array.GetArray(), arg_array.GetNumBytes(), &result, "VL"); 2499 } 2500 cleared_references_.Clear(); 2501 } 2502} 2503 2504void Heap::RequestConcurrentGC(Thread* self) { 2505 // Make sure that we can do a concurrent GC. 2506 Runtime* runtime = Runtime::Current(); 2507 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2508 self->IsHandlingStackOverflow()) { 2509 return; 2510 } 2511 // We already have a request pending, no reason to start more until we update 2512 // concurrent_start_bytes_. 2513 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2514 JNIEnv* env = self->GetJniEnv(); 2515 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2516 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2517 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2518 WellKnownClasses::java_lang_Daemons_requestGC); 2519 CHECK(!env->ExceptionCheck()); 2520} 2521 2522void Heap::ConcurrentGC(Thread* self) { 2523 if (Runtime::Current()->IsShuttingDown(self)) { 2524 return; 2525 } 2526 // Wait for any GCs currently running to finish. 2527 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2528 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2529 // instead. E.g. can't do partial, so do full instead. 2530 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2531 collector::kGcTypeNone) { 2532 for (collector::GcType gc_type : gc_plan_) { 2533 // Attempt to run the collector, if we succeed, we are done. 2534 if (gc_type > next_gc_type_ && 2535 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2536 break; 2537 } 2538 } 2539 } 2540 } 2541} 2542 2543void Heap::RequestHeapTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2544 Thread* self = Thread::Current(); 2545 { 2546 MutexLock mu(self, *heap_trim_request_lock_); 2547 if (desired_collector_type_ == desired_collector_type) { 2548 return; 2549 } 2550 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2551 desired_collector_type_ = desired_collector_type; 2552 } 2553 SignalHeapTrimDaemon(self); 2554} 2555 2556void Heap::RequestHeapTrim(uint64_t delta_time) { 2557 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2558 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2559 // a space it will hold its lock and can become a cause of jank. 2560 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2561 // forking. 2562 2563 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2564 // because that only marks object heads, so a large array looks like lots of empty space. We 2565 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2566 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2567 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2568 // not how much use we're making of those pages. 2569 2570 Thread* self = Thread::Current(); 2571 Runtime* runtime = Runtime::Current(); 2572 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2573 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2574 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2575 // as we don't hold the lock while requesting the trim). 2576 return; 2577 } 2578 2579 // Request a heap trim only if we do not currently care about pause times. 2580 if (!CareAboutPauseTimes()) { 2581 { 2582 MutexLock mu(self, *heap_trim_request_lock_); 2583 heap_trim_target_time_ = std::max(heap_trim_target_time_, NanoTime() + delta_time); 2584 heap_trim_request_pending_ = true; 2585 } 2586 // Notify the daemon thread which will actually do the heap trim. 2587 SignalHeapTrimDaemon(self); 2588 } 2589} 2590 2591void Heap::SignalHeapTrimDaemon(Thread* self) { 2592 JNIEnv* env = self->GetJniEnv(); 2593 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2594 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2595 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2596 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2597 CHECK(!env->ExceptionCheck()); 2598} 2599 2600void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2601 if (rosalloc_space_ != nullptr) { 2602 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2603 } 2604 if (bump_pointer_space_ != nullptr) { 2605 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2606 } 2607} 2608 2609void Heap::RevokeAllThreadLocalBuffers() { 2610 if (rosalloc_space_ != nullptr) { 2611 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2612 } 2613 if (bump_pointer_space_ != nullptr) { 2614 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2615 } 2616} 2617 2618bool Heap::IsGCRequestPending() const { 2619 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2620} 2621 2622void Heap::RunFinalization(JNIEnv* env) { 2623 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2624 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2625 CHECK(WellKnownClasses::java_lang_System != nullptr); 2626 WellKnownClasses::java_lang_System_runFinalization = 2627 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2628 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2629 } 2630 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2631 WellKnownClasses::java_lang_System_runFinalization); 2632} 2633 2634void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2635 Thread* self = ThreadForEnv(env); 2636 if (native_need_to_run_finalization_) { 2637 RunFinalization(env); 2638 UpdateMaxNativeFootprint(); 2639 native_need_to_run_finalization_ = false; 2640 } 2641 // Total number of native bytes allocated. 2642 native_bytes_allocated_.FetchAndAdd(bytes); 2643 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2644 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2645 collector::kGcTypeFull; 2646 2647 // The second watermark is higher than the gc watermark. If you hit this it means you are 2648 // allocating native objects faster than the GC can keep up with. 2649 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2650 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2651 // Just finished a GC, attempt to run finalizers. 2652 RunFinalization(env); 2653 CHECK(!env->ExceptionCheck()); 2654 } 2655 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2656 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2657 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2658 RunFinalization(env); 2659 native_need_to_run_finalization_ = false; 2660 CHECK(!env->ExceptionCheck()); 2661 } 2662 // We have just run finalizers, update the native watermark since it is very likely that 2663 // finalizers released native managed allocations. 2664 UpdateMaxNativeFootprint(); 2665 } else if (!IsGCRequestPending()) { 2666 if (concurrent_gc_) { 2667 RequestConcurrentGC(self); 2668 } else { 2669 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2670 } 2671 } 2672 } 2673} 2674 2675void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2676 int expected_size, new_size; 2677 do { 2678 expected_size = native_bytes_allocated_.Load(); 2679 new_size = expected_size - bytes; 2680 if (UNLIKELY(new_size < 0)) { 2681 ScopedObjectAccess soa(env); 2682 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2683 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2684 "registered as allocated", bytes, expected_size).c_str()); 2685 break; 2686 } 2687 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2688} 2689 2690size_t Heap::GetTotalMemory() const { 2691 size_t ret = 0; 2692 for (const auto& space : continuous_spaces_) { 2693 // Currently don't include the image space. 2694 if (!space->IsImageSpace()) { 2695 ret += space->Size(); 2696 } 2697 } 2698 for (const auto& space : discontinuous_spaces_) { 2699 if (space->IsLargeObjectSpace()) { 2700 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2701 } 2702 } 2703 return ret; 2704} 2705 2706void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2707 DCHECK(mod_union_table != nullptr); 2708 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2709} 2710 2711void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2712 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2713 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2714 strlen(ClassHelper(c).GetDescriptor()) == 0); 2715 CHECK_GE(byte_count, sizeof(mirror::Object)); 2716} 2717 2718} // namespace gc 2719} // namespace art 2720