heap.cc revision da44d773dedf8aae6153e3423012f236cba3bfcd
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 25#include "base/histogram-inl.h" 26#include "base/stl_util.h" 27#include "common_throws.h" 28#include "cutils/sched_policy.h" 29#include "debugger.h" 30#include "gc/accounting/atomic_stack.h" 31#include "gc/accounting/card_table-inl.h" 32#include "gc/accounting/heap_bitmap-inl.h" 33#include "gc/accounting/mod_union_table.h" 34#include "gc/accounting/mod_union_table-inl.h" 35#include "gc/accounting/remembered_set.h" 36#include "gc/accounting/space_bitmap-inl.h" 37#include "gc/collector/concurrent_copying.h" 38#include "gc/collector/mark_sweep-inl.h" 39#include "gc/collector/partial_mark_sweep.h" 40#include "gc/collector/semi_space.h" 41#include "gc/collector/sticky_mark_sweep.h" 42#include "gc/space/bump_pointer_space.h" 43#include "gc/space/dlmalloc_space-inl.h" 44#include "gc/space/image_space.h" 45#include "gc/space/large_object_space.h" 46#include "gc/space/rosalloc_space-inl.h" 47#include "gc/space/space-inl.h" 48#include "gc/space/zygote_space.h" 49#include "entrypoints/quick/quick_alloc_entrypoints.h" 50#include "heap-inl.h" 51#include "image.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 "mirror/reference-inl.h" 58#include "object_utils.h" 59#include "os.h" 60#include "reflection.h" 61#include "runtime.h" 62#include "ScopedLocalRef.h" 63#include "scoped_thread_state_change.h" 64#include "sirt_ref.h" 65#include "thread_list.h" 66#include "UniquePtr.h" 67#include "well_known_classes.h" 68 69namespace art { 70 71namespace gc { 72 73static constexpr size_t kCollectorTransitionStressIterations = 0; 74static constexpr size_t kCollectorTransitionStressWait = 10 * 1000; // Microseconds 75static constexpr bool kGCALotMode = false; 76static constexpr size_t kGcAlotInterval = KB; 77// Minimum amount of remaining bytes before a concurrent GC is triggered. 78static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 79static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 80 81Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 82 double target_utilization, size_t capacity, const std::string& image_file_name, 83 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 84 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 85 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 86 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 87 bool verify_post_gc_heap, bool verify_pre_gc_rosalloc, 88 bool verify_post_gc_rosalloc) 89 : non_moving_space_(nullptr), 90 rosalloc_space_(nullptr), 91 dlmalloc_space_(nullptr), 92 main_space_(nullptr), 93 collector_type_(kCollectorTypeNone), 94 post_zygote_collector_type_(post_zygote_collector_type), 95 background_collector_type_(background_collector_type), 96 desired_collector_type_(collector_type_), 97 heap_trim_request_lock_(nullptr), 98 last_trim_time_(0), 99 heap_transition_target_time_(0), 100 heap_trim_request_pending_(false), 101 parallel_gc_threads_(parallel_gc_threads), 102 conc_gc_threads_(conc_gc_threads), 103 low_memory_mode_(low_memory_mode), 104 long_pause_log_threshold_(long_pause_log_threshold), 105 long_gc_log_threshold_(long_gc_log_threshold), 106 ignore_max_footprint_(ignore_max_footprint), 107 have_zygote_space_(false), 108 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 109 collector_type_running_(kCollectorTypeNone), 110 last_gc_type_(collector::kGcTypeNone), 111 next_gc_type_(collector::kGcTypePartial), 112 capacity_(capacity), 113 growth_limit_(growth_limit), 114 max_allowed_footprint_(initial_size), 115 native_footprint_gc_watermark_(initial_size), 116 native_footprint_limit_(2 * initial_size), 117 native_need_to_run_finalization_(false), 118 // Initially assume we perceive jank in case the process state is never updated. 119 process_state_(kProcessStateJankPerceptible), 120 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 121 total_bytes_freed_ever_(0), 122 total_objects_freed_ever_(0), 123 num_bytes_allocated_(0), 124 native_bytes_allocated_(0), 125 gc_memory_overhead_(0), 126 verify_missing_card_marks_(false), 127 verify_system_weaks_(false), 128 verify_pre_gc_heap_(verify_pre_gc_heap), 129 verify_post_gc_heap_(verify_post_gc_heap), 130 verify_mod_union_table_(false), 131 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 132 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 133 allocation_rate_(0), 134 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 135 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 136 * verification is enabled, we limit the size of allocation stacks to speed up their 137 * searching. 138 */ 139 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 140 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 141 current_allocator_(kAllocatorTypeDlMalloc), 142 current_non_moving_allocator_(kAllocatorTypeNonMoving), 143 bump_pointer_space_(nullptr), 144 temp_space_(nullptr), 145 min_free_(min_free), 146 max_free_(max_free), 147 target_utilization_(target_utilization), 148 total_wait_time_(0), 149 total_allocation_time_(0), 150 verify_object_mode_(kVerifyObjectModeDisabled), 151 disable_moving_gc_count_(0), 152 running_on_valgrind_(Runtime::Current()->RunningOnValgrind()), 153 use_tlab_(use_tlab) { 154 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 155 LOG(INFO) << "Heap() entering"; 156 } 157 const bool is_zygote = Runtime::Current()->IsZygote(); 158 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 159 // entrypoints. 160 if (!is_zygote) { 161 desired_collector_type_ = post_zygote_collector_type_; 162 large_object_threshold_ = kDefaultLargeObjectThreshold; 163 } else { 164 if (kMovingCollector) { 165 // We are the zygote, use bump pointer allocation + semi space collector. 166 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 167 desired_collector_type_ = generational ? kCollectorTypeGSS : kCollectorTypeSS; 168 } else { 169 desired_collector_type_ = post_zygote_collector_type_; 170 } 171 } 172 ChangeCollector(desired_collector_type_); 173 174 live_bitmap_.reset(new accounting::HeapBitmap(this)); 175 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 176 // Requested begin for the alloc space, to follow the mapped image and oat files 177 byte* requested_alloc_space_begin = nullptr; 178 if (!image_file_name.empty()) { 179 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 180 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 181 AddSpace(image_space); 182 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 183 // isn't going to get in the middle 184 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 185 CHECK_GT(oat_file_end_addr, image_space->End()); 186 if (oat_file_end_addr > requested_alloc_space_begin) { 187 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 188 } 189 } 190 MemMap* malloc_space_mem_map = nullptr; 191 const char* malloc_space_name = is_zygote ? "zygote space" : "alloc space"; 192 if (is_zygote) { 193 // Allocate a single mem map that is split into the malloc space 194 // and the post zygote non-moving space to put them adjacent. 195 size_t post_zygote_non_moving_space_size = 64 * MB; 196 size_t non_moving_spaces_size = capacity + post_zygote_non_moving_space_size; 197 std::string error_str; 198 malloc_space_mem_map = MemMap::MapAnonymous(malloc_space_name, requested_alloc_space_begin, 199 non_moving_spaces_size, PROT_READ | PROT_WRITE, 200 true, &error_str); 201 CHECK(malloc_space_mem_map != nullptr) << error_str; 202 post_zygote_non_moving_space_mem_map_.reset(malloc_space_mem_map->RemapAtEnd( 203 malloc_space_mem_map->Begin() + capacity, "post zygote non-moving space", 204 PROT_READ | PROT_WRITE, &error_str)); 205 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 206 VLOG(heap) << "malloc space mem map : " << malloc_space_mem_map; 207 VLOG(heap) << "post zygote non-moving space mem map : " 208 << post_zygote_non_moving_space_mem_map_.get(); 209 } else { 210 // Allocate a mem map for the malloc space. 211 std::string error_str; 212 malloc_space_mem_map = MemMap::MapAnonymous(malloc_space_name, requested_alloc_space_begin, 213 capacity, PROT_READ | PROT_WRITE, true, &error_str); 214 CHECK(malloc_space_mem_map != nullptr) << error_str; 215 VLOG(heap) << "malloc space mem map : " << malloc_space_mem_map; 216 } 217 CHECK(malloc_space_mem_map != nullptr); 218 space::MallocSpace* malloc_space; 219 if (kUseRosAlloc) { 220 malloc_space = space::RosAllocSpace::CreateFromMemMap(malloc_space_mem_map, malloc_space_name, 221 kDefaultStartingSize, initial_size, 222 growth_limit, capacity, low_memory_mode_); 223 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 224 } else { 225 malloc_space = space::DlMallocSpace::CreateFromMemMap(malloc_space_mem_map, malloc_space_name, 226 kDefaultStartingSize, initial_size, 227 growth_limit, capacity); 228 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 229 } 230 VLOG(heap) << "malloc_space : " << malloc_space; 231 if (kMovingCollector) { 232 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 233 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 234 // issues. 235 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 236 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 237 bump_pointer_space_size, nullptr); 238 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 239 AddSpace(bump_pointer_space_); 240 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 241 nullptr); 242 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 243 AddSpace(temp_space_); 244 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 245 VLOG(heap) << "temp_space : " << temp_space_; 246 } 247 non_moving_space_ = malloc_space; 248 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 249 AddSpace(malloc_space); 250 251 // Allocate the large object space. 252 constexpr bool kUseFreeListSpaceForLOS = false; 253 if (kUseFreeListSpaceForLOS) { 254 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 255 } else { 256 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 257 } 258 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 259 AddSpace(large_object_space_); 260 261 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 262 CHECK(!continuous_spaces_.empty()); 263 264 // Relies on the spaces being sorted. 265 byte* heap_begin = continuous_spaces_.front()->Begin(); 266 byte* heap_end = continuous_spaces_.back()->Limit(); 267 if (is_zygote) { 268 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr); 269 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 270 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 271 } 272 size_t heap_capacity = heap_end - heap_begin; 273 274 // Allocate the card table. 275 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 276 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 277 278 // Card cache for now since it makes it easier for us to update the references to the copying 279 // spaces. 280 accounting::ModUnionTable* mod_union_table = 281 new accounting::ModUnionTableToZygoteAllocspace("Image mod-union table", this, 282 GetImageSpace()); 283 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 284 AddModUnionTable(mod_union_table); 285 286 if (collector::SemiSpace::kUseRememberedSet) { 287 accounting::RememberedSet* non_moving_space_rem_set = 288 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 289 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 290 AddRememberedSet(non_moving_space_rem_set); 291 } 292 293 // TODO: Count objects in the image space here. 294 num_bytes_allocated_ = 0; 295 296 // Default mark stack size in bytes. 297 static const size_t default_mark_stack_size = 64 * KB; 298 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 299 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 300 max_allocation_stack_size_)); 301 live_stack_.reset(accounting::ObjectStack::Create("live stack", 302 max_allocation_stack_size_)); 303 304 // It's still too early to take a lock because there are no threads yet, but we can create locks 305 // now. We don't create it earlier to make it clear that you can't use locks during heap 306 // initialization. 307 gc_complete_lock_ = new Mutex("GC complete lock"); 308 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 309 *gc_complete_lock_)); 310 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 311 last_gc_size_ = GetBytesAllocated(); 312 313 if (ignore_max_footprint_) { 314 SetIdealFootprint(std::numeric_limits<size_t>::max()); 315 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 316 } 317 CHECK_NE(max_allowed_footprint_, 0U); 318 319 // Create our garbage collectors. 320 for (size_t i = 0; i < 2; ++i) { 321 const bool concurrent = i != 0; 322 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 323 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 324 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 325 } 326 if (kMovingCollector) { 327 // TODO: Clean this up. 328 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 329 semi_space_collector_ = new collector::SemiSpace(this, generational); 330 garbage_collectors_.push_back(semi_space_collector_); 331 332 concurrent_copying_collector_ = new collector::ConcurrentCopying(this); 333 garbage_collectors_.push_back(concurrent_copying_collector_); 334 } 335 336 if (running_on_valgrind_) { 337 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 338 } 339 340 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 341 LOG(INFO) << "Heap() exiting"; 342 } 343} 344 345void Heap::ChangeAllocator(AllocatorType allocator) { 346 if (current_allocator_ != allocator) { 347 // These two allocators are only used internally and don't have any entrypoints. 348 CHECK_NE(allocator, kAllocatorTypeLOS); 349 CHECK_NE(allocator, kAllocatorTypeNonMoving); 350 current_allocator_ = allocator; 351 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 352 SetQuickAllocEntryPointsAllocator(current_allocator_); 353 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 354 } 355} 356 357void Heap::DisableCompaction() { 358 if (IsCompactingGC(post_zygote_collector_type_)) { 359 post_zygote_collector_type_ = kCollectorTypeCMS; 360 } 361 if (IsCompactingGC(background_collector_type_)) { 362 background_collector_type_ = post_zygote_collector_type_; 363 } 364 TransitionCollector(post_zygote_collector_type_); 365} 366 367std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 368 if (!IsValidContinuousSpaceObjectAddress(klass)) { 369 return StringPrintf("<non heap address klass %p>", klass); 370 } 371 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 372 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 373 std::string result("["); 374 result += SafeGetClassDescriptor(component_type); 375 return result; 376 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 377 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 378 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 379 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 380 } else { 381 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 382 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 383 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 384 } 385 const DexFile* dex_file = dex_cache->GetDexFile(); 386 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 387 if (class_def_idx == DexFile::kDexNoIndex16) { 388 return "<class def not found>"; 389 } 390 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 391 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 392 return dex_file->GetTypeDescriptor(type_id); 393 } 394} 395 396std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 397 if (obj == nullptr) { 398 return "null"; 399 } 400 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 401 if (klass == nullptr) { 402 return "(class=null)"; 403 } 404 std::string result(SafeGetClassDescriptor(klass)); 405 if (obj->IsClass()) { 406 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 407 } 408 return result; 409} 410 411void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 412 if (obj == nullptr) { 413 stream << "(obj=null)"; 414 return; 415 } 416 if (IsAligned<kObjectAlignment>(obj)) { 417 space::Space* space = nullptr; 418 // Don't use find space since it only finds spaces which actually contain objects instead of 419 // spaces which may contain objects (e.g. cleared bump pointer spaces). 420 for (const auto& cur_space : continuous_spaces_) { 421 if (cur_space->HasAddress(obj)) { 422 space = cur_space; 423 break; 424 } 425 } 426 if (space == nullptr) { 427 if (allocator_mem_map_.get() == nullptr || !allocator_mem_map_->HasAddress(obj)) { 428 stream << "obj " << obj << " not a valid heap address"; 429 return; 430 } else if (allocator_mem_map_.get() != nullptr) { 431 allocator_mem_map_->Protect(PROT_READ | PROT_WRITE); 432 } 433 } 434 // Unprotect all the spaces. 435 for (const auto& space : continuous_spaces_) { 436 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 437 } 438 stream << "Object " << obj; 439 if (space != nullptr) { 440 stream << " in space " << *space; 441 } 442 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 443 stream << "\nclass=" << klass; 444 if (klass != nullptr) { 445 stream << " type= " << SafePrettyTypeOf(obj); 446 } 447 // Re-protect the address we faulted on. 448 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 449 } 450} 451 452bool Heap::IsCompilingBoot() const { 453 for (const auto& space : continuous_spaces_) { 454 if (space->IsImageSpace() || space->IsZygoteSpace()) { 455 return false; 456 } 457 } 458 return true; 459} 460 461bool Heap::HasImageSpace() const { 462 for (const auto& space : continuous_spaces_) { 463 if (space->IsImageSpace()) { 464 return true; 465 } 466 } 467 return false; 468} 469 470void Heap::IncrementDisableMovingGC(Thread* self) { 471 // Need to do this holding the lock to prevent races where the GC is about to run / running when 472 // we attempt to disable it. 473 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 474 MutexLock mu(self, *gc_complete_lock_); 475 ++disable_moving_gc_count_; 476 if (IsCompactingGC(collector_type_running_)) { 477 WaitForGcToCompleteLocked(self); 478 } 479} 480 481void Heap::DecrementDisableMovingGC(Thread* self) { 482 MutexLock mu(self, *gc_complete_lock_); 483 CHECK_GE(disable_moving_gc_count_, 0U); 484 --disable_moving_gc_count_; 485} 486 487void Heap::UpdateProcessState(ProcessState process_state) { 488 if (process_state_ != process_state) { 489 process_state_ = process_state; 490 for (size_t i = 1; i <= kCollectorTransitionStressIterations; ++i) { 491 // Start at index 1 to avoid "is always false" warning. 492 // Have iteration 1 always transition the collector. 493 TransitionCollector((((i & 1) == 1) == (process_state_ == kProcessStateJankPerceptible)) 494 ? post_zygote_collector_type_ : background_collector_type_); 495 usleep(kCollectorTransitionStressWait); 496 } 497 if (process_state_ == kProcessStateJankPerceptible) { 498 // Transition back to foreground right away to prevent jank. 499 RequestCollectorTransition(post_zygote_collector_type_, 0); 500 } else { 501 // Don't delay for debug builds since we may want to stress test the GC. 502 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 503 kCollectorTransitionWait); 504 } 505 } 506} 507 508void Heap::CreateThreadPool() { 509 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 510 if (num_threads != 0) { 511 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 512 } 513} 514 515void Heap::VisitObjects(ObjectCallback callback, void* arg) { 516 Thread* self = Thread::Current(); 517 // GCs can move objects, so don't allow this. 518 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 519 if (bump_pointer_space_ != nullptr) { 520 // Visit objects in bump pointer space. 521 bump_pointer_space_->Walk(callback, arg); 522 } 523 // TODO: Switch to standard begin and end to use ranged a based loop. 524 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 525 it < end; ++it) { 526 mirror::Object* obj = *it; 527 if (obj != nullptr && obj->GetClass() != nullptr) { 528 // Avoid the race condition caused by the object not yet being written into the allocation 529 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 530 // there can be nulls on the allocation stack. 531 callback(obj, arg); 532 } 533 } 534 GetLiveBitmap()->Walk(callback, arg); 535 self->EndAssertNoThreadSuspension(old_cause); 536} 537 538void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 539 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 540 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 541 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 542 // TODO: Generalize this to n bitmaps? 543 if (space1 == nullptr) { 544 DCHECK(space2 != nullptr); 545 space1 = space2; 546 } 547 if (space2 == nullptr) { 548 DCHECK(space1 != nullptr); 549 space2 = space1; 550 } 551 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 552 large_object_space_->GetLiveObjects(), stack); 553} 554 555void Heap::DeleteThreadPool() { 556 thread_pool_.reset(nullptr); 557} 558 559void Heap::AddSpace(space::Space* space, bool set_as_default) { 560 DCHECK(space != nullptr); 561 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 562 if (space->IsContinuousSpace()) { 563 DCHECK(!space->IsDiscontinuousSpace()); 564 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 565 // Continuous spaces don't necessarily have bitmaps. 566 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 567 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 568 if (live_bitmap != nullptr) { 569 DCHECK(mark_bitmap != nullptr); 570 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 571 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 572 } 573 continuous_spaces_.push_back(continuous_space); 574 if (set_as_default) { 575 if (continuous_space->IsDlMallocSpace()) { 576 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 577 } else if (continuous_space->IsRosAllocSpace()) { 578 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 579 } 580 } 581 // Ensure that spaces remain sorted in increasing order of start address. 582 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 583 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 584 return a->Begin() < b->Begin(); 585 }); 586 } else { 587 DCHECK(space->IsDiscontinuousSpace()); 588 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 589 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 590 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 591 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 592 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 593 discontinuous_spaces_.push_back(discontinuous_space); 594 } 595 if (space->IsAllocSpace()) { 596 alloc_spaces_.push_back(space->AsAllocSpace()); 597 } 598} 599 600void Heap::RemoveSpace(space::Space* space) { 601 DCHECK(space != nullptr); 602 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 603 if (space->IsContinuousSpace()) { 604 DCHECK(!space->IsDiscontinuousSpace()); 605 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 606 // Continuous spaces don't necessarily have bitmaps. 607 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 608 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 609 if (live_bitmap != nullptr) { 610 DCHECK(mark_bitmap != nullptr); 611 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 612 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 613 } 614 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 615 DCHECK(it != continuous_spaces_.end()); 616 continuous_spaces_.erase(it); 617 if (continuous_space == dlmalloc_space_) { 618 dlmalloc_space_ = nullptr; 619 } else if (continuous_space == rosalloc_space_) { 620 rosalloc_space_ = nullptr; 621 } 622 if (continuous_space == main_space_) { 623 main_space_ = nullptr; 624 } 625 } else { 626 DCHECK(space->IsDiscontinuousSpace()); 627 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 628 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 629 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 630 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 631 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 632 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 633 discontinuous_space); 634 DCHECK(it != discontinuous_spaces_.end()); 635 discontinuous_spaces_.erase(it); 636 } 637 if (space->IsAllocSpace()) { 638 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 639 DCHECK(it != alloc_spaces_.end()); 640 alloc_spaces_.erase(it); 641 } 642} 643 644void Heap::RegisterGCAllocation(size_t bytes) { 645 if (this != nullptr) { 646 gc_memory_overhead_.FetchAndAdd(bytes); 647 } 648} 649 650void Heap::RegisterGCDeAllocation(size_t bytes) { 651 if (this != nullptr) { 652 gc_memory_overhead_.FetchAndSub(bytes); 653 } 654} 655 656void Heap::DumpGcPerformanceInfo(std::ostream& os) { 657 // Dump cumulative timings. 658 os << "Dumping cumulative Gc timings\n"; 659 uint64_t total_duration = 0; 660 661 // Dump cumulative loggers for each GC type. 662 uint64_t total_paused_time = 0; 663 for (const auto& collector : garbage_collectors_) { 664 const CumulativeLogger& logger = collector->GetCumulativeTimings(); 665 if (logger.GetTotalNs() != 0) { 666 os << ConstDumpable<CumulativeLogger>(logger); 667 const uint64_t total_ns = logger.GetTotalNs(); 668 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 669 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 670 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 671 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 672 Histogram<uint64_t>::CumulativeData cumulative_data; 673 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 674 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 675 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 676 << collector->GetName() << " freed: " << freed_objects 677 << " objects with total size " << PrettySize(freed_bytes) << "\n" 678 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 679 << PrettySize(freed_bytes / seconds) << "/s\n"; 680 total_duration += total_ns; 681 total_paused_time += total_pause_ns; 682 } 683 } 684 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 685 if (total_duration != 0) { 686 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 687 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 688 os << "Mean GC size throughput: " 689 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 690 os << "Mean GC object throughput: " 691 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 692 } 693 size_t total_objects_allocated = GetObjectsAllocatedEver(); 694 os << "Total number of allocations: " << total_objects_allocated << "\n"; 695 size_t total_bytes_allocated = GetBytesAllocatedEver(); 696 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 697 if (kMeasureAllocationTime) { 698 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 699 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 700 << "\n"; 701 } 702 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 703 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 704 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 705} 706 707Heap::~Heap() { 708 VLOG(heap) << "Starting ~Heap()"; 709 STLDeleteElements(&garbage_collectors_); 710 // If we don't reset then the mark stack complains in its destructor. 711 allocation_stack_->Reset(); 712 live_stack_->Reset(); 713 STLDeleteValues(&mod_union_tables_); 714 STLDeleteValues(&remembered_sets_); 715 STLDeleteElements(&continuous_spaces_); 716 STLDeleteElements(&discontinuous_spaces_); 717 delete gc_complete_lock_; 718 delete heap_trim_request_lock_; 719 VLOG(heap) << "Finished ~Heap()"; 720} 721 722space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 723 bool fail_ok) const { 724 for (const auto& space : continuous_spaces_) { 725 if (space->Contains(obj)) { 726 return space; 727 } 728 } 729 if (!fail_ok) { 730 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 731 } 732 return NULL; 733} 734 735space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 736 bool fail_ok) const { 737 for (const auto& space : discontinuous_spaces_) { 738 if (space->Contains(obj)) { 739 return space; 740 } 741 } 742 if (!fail_ok) { 743 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 744 } 745 return NULL; 746} 747 748space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 749 space::Space* result = FindContinuousSpaceFromObject(obj, true); 750 if (result != NULL) { 751 return result; 752 } 753 return FindDiscontinuousSpaceFromObject(obj, true); 754} 755 756struct SoftReferenceArgs { 757 IsMarkedCallback* is_marked_callback_; 758 MarkObjectCallback* mark_callback_; 759 void* arg_; 760}; 761 762mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 763 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 764 // TODO: Not preserve all soft references. 765 return args->mark_callback_(obj, args->arg_); 766} 767 768void Heap::ProcessSoftReferences(TimingLogger& timings, bool clear_soft, 769 IsMarkedCallback* is_marked_callback, 770 MarkObjectCallback* mark_object_callback, 771 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 772 // Unless required to clear soft references with white references, preserve some white referents. 773 if (!clear_soft) { 774 // Don't clear for sticky GC. 775 SoftReferenceArgs soft_reference_args; 776 soft_reference_args.is_marked_callback_ = is_marked_callback; 777 soft_reference_args.mark_callback_ = mark_object_callback; 778 soft_reference_args.arg_ = arg; 779 // References with a marked referent are removed from the list. 780 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 781 &soft_reference_args); 782 process_mark_stack_callback(arg); 783 } 784} 785 786// Process reference class instances and schedule finalizations. 787void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 788 IsMarkedCallback* is_marked_callback, 789 MarkObjectCallback* mark_object_callback, 790 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 791 timings.StartSplit("(Paused)ProcessReferences"); 792 ProcessSoftReferences(timings, clear_soft, is_marked_callback, mark_object_callback, 793 process_mark_stack_callback, arg); 794 // Clear all remaining soft and weak references with white referents. 795 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 796 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 797 timings.EndSplit(); 798 // Preserve all white objects with finalize methods and schedule them for finalization. 799 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 800 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 801 mark_object_callback, arg); 802 process_mark_stack_callback(arg); 803 timings.EndSplit(); 804 timings.StartSplit("(Paused)ProcessReferences"); 805 // Clear all f-reachable soft and weak references with white referents. 806 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 807 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 808 // Clear all phantom references with white referents. 809 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 810 // At this point all reference queues other than the cleared references should be empty. 811 DCHECK(soft_reference_queue_.IsEmpty()); 812 DCHECK(weak_reference_queue_.IsEmpty()); 813 DCHECK(finalizer_reference_queue_.IsEmpty()); 814 DCHECK(phantom_reference_queue_.IsEmpty()); 815 timings.EndSplit(); 816} 817 818// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 819// marked, put it on the appropriate list in the heap for later processing. 820void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Reference* ref, 821 IsMarkedCallback is_marked_callback, void* arg) { 822 // klass can be the class of the old object if the visitor already updated the class of ref. 823 DCHECK(klass->IsReferenceClass()); 824 mirror::Object* referent = ref->GetReferent(); 825 if (referent != nullptr) { 826 mirror::Object* forward_address = is_marked_callback(referent, arg); 827 // Null means that the object is not currently marked. 828 if (forward_address == nullptr) { 829 Thread* self = Thread::Current(); 830 // TODO: Remove these locks, and use atomic stacks for storing references? 831 // We need to check that the references haven't already been enqueued since we can end up 832 // scanning the same reference multiple times due to dirty cards. 833 if (klass->IsSoftReferenceClass()) { 834 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 835 } else if (klass->IsWeakReferenceClass()) { 836 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 837 } else if (klass->IsFinalizerReferenceClass()) { 838 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 839 } else if (klass->IsPhantomReferenceClass()) { 840 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 841 } else { 842 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 843 << klass->GetAccessFlags(); 844 } 845 } else if (referent != forward_address) { 846 // Referent is already marked and we need to update it. 847 ref->SetReferent<false>(forward_address); 848 } 849 } 850} 851 852space::ImageSpace* Heap::GetImageSpace() const { 853 for (const auto& space : continuous_spaces_) { 854 if (space->IsImageSpace()) { 855 return space->AsImageSpace(); 856 } 857 } 858 return NULL; 859} 860 861static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 862 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 863 if (used_bytes < chunk_size) { 864 size_t chunk_free_bytes = chunk_size - used_bytes; 865 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 866 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 867 } 868} 869 870void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 871 std::ostringstream oss; 872 size_t total_bytes_free = GetFreeMemory(); 873 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 874 << " free bytes"; 875 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 876 if (!large_object_allocation && total_bytes_free >= byte_count) { 877 size_t max_contiguous_allocation = 0; 878 for (const auto& space : continuous_spaces_) { 879 if (space->IsMallocSpace()) { 880 // To allow the Walk/InspectAll() to exclusively-lock the mutator 881 // lock, temporarily release the shared access to the mutator 882 // lock here by transitioning to the suspended state. 883 Locks::mutator_lock_->AssertSharedHeld(self); 884 self->TransitionFromRunnableToSuspended(kSuspended); 885 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 886 self->TransitionFromSuspendedToRunnable(); 887 Locks::mutator_lock_->AssertSharedHeld(self); 888 } 889 } 890 oss << "; failed due to fragmentation (largest possible contiguous allocation " 891 << max_contiguous_allocation << " bytes)"; 892 } 893 self->ThrowOutOfMemoryError(oss.str().c_str()); 894} 895 896void Heap::DoPendingTransitionOrTrim() { 897 Thread* self = Thread::Current(); 898 CollectorType desired_collector_type; 899 // Wait until we reach the desired transition time. 900 while (true) { 901 uint64_t wait_time; 902 { 903 MutexLock mu(self, *heap_trim_request_lock_); 904 desired_collector_type = desired_collector_type_; 905 uint64_t current_time = NanoTime(); 906 if (current_time >= heap_transition_target_time_) { 907 break; 908 } 909 wait_time = heap_transition_target_time_ - current_time; 910 } 911 ScopedThreadStateChange tsc(self, kSleeping); 912 usleep(wait_time / 1000); // Usleep takes microseconds. 913 } 914 // Transition the collector if the desired collector type is not the same as the current 915 // collector type. 916 TransitionCollector(desired_collector_type); 917 // Do a heap trim if it is needed. 918 Trim(); 919} 920 921void Heap::Trim() { 922 Thread* self = Thread::Current(); 923 { 924 MutexLock mu(self, *heap_trim_request_lock_); 925 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 926 return; 927 } 928 last_trim_time_ = NanoTime(); 929 heap_trim_request_pending_ = false; 930 } 931 { 932 // Need to do this before acquiring the locks since we don't want to get suspended while 933 // holding any locks. 934 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 935 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 936 // trimming. 937 MutexLock mu(self, *gc_complete_lock_); 938 // Ensure there is only one GC at a time. 939 WaitForGcToCompleteLocked(self); 940 collector_type_running_ = kCollectorTypeHeapTrim; 941 } 942 uint64_t start_ns = NanoTime(); 943 // Trim the managed spaces. 944 uint64_t total_alloc_space_allocated = 0; 945 uint64_t total_alloc_space_size = 0; 946 uint64_t managed_reclaimed = 0; 947 for (const auto& space : continuous_spaces_) { 948 if (space->IsMallocSpace()) { 949 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 950 total_alloc_space_size += alloc_space->Size(); 951 managed_reclaimed += alloc_space->Trim(); 952 } 953 } 954 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 955 bump_pointer_space_->Size(); 956 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 957 static_cast<float>(total_alloc_space_size); 958 uint64_t gc_heap_end_ns = NanoTime(); 959 // We never move things in the native heap, so we can finish the GC at this point. 960 FinishGC(self, collector::kGcTypeNone); 961 // Trim the native heap. 962 dlmalloc_trim(0); 963 size_t native_reclaimed = 0; 964 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 965 uint64_t end_ns = NanoTime(); 966 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 967 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 968 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 969 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 970 << "%."; 971} 972 973bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 974 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 975 // taking the lock. 976 if (obj == nullptr) { 977 return true; 978 } 979 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 980} 981 982bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 983 return FindContinuousSpaceFromObject(obj, true) != nullptr; 984} 985 986bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 987 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 988 return false; 989 } 990 for (const auto& space : continuous_spaces_) { 991 if (space->HasAddress(obj)) { 992 return true; 993 } 994 } 995 return false; 996} 997 998bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 999 bool search_live_stack, bool sorted) { 1000 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 1001 return false; 1002 } 1003 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 1004 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 1005 if (obj == klass) { 1006 // This case happens for java.lang.Class. 1007 return true; 1008 } 1009 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 1010 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 1011 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 1012 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 1013 return temp_space_->Contains(obj); 1014 } 1015 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1016 space::DiscontinuousSpace* d_space = NULL; 1017 if (c_space != nullptr) { 1018 if (c_space->GetLiveBitmap()->Test(obj)) { 1019 return true; 1020 } 1021 } else { 1022 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1023 if (d_space != nullptr) { 1024 if (d_space->GetLiveObjects()->Test(obj)) { 1025 return true; 1026 } 1027 } 1028 } 1029 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1030 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1031 if (i > 0) { 1032 NanoSleep(MsToNs(10)); 1033 } 1034 if (search_allocation_stack) { 1035 if (sorted) { 1036 if (allocation_stack_->ContainsSorted(obj)) { 1037 return true; 1038 } 1039 } else if (allocation_stack_->Contains(obj)) { 1040 return true; 1041 } 1042 } 1043 1044 if (search_live_stack) { 1045 if (sorted) { 1046 if (live_stack_->ContainsSorted(obj)) { 1047 return true; 1048 } 1049 } else if (live_stack_->Contains(obj)) { 1050 return true; 1051 } 1052 } 1053 } 1054 // We need to check the bitmaps again since there is a race where we mark something as live and 1055 // then clear the stack containing it. 1056 if (c_space != nullptr) { 1057 if (c_space->GetLiveBitmap()->Test(obj)) { 1058 return true; 1059 } 1060 } else { 1061 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1062 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 1063 return true; 1064 } 1065 } 1066 return false; 1067} 1068 1069void Heap::DumpSpaces(std::ostream& stream) { 1070 for (const auto& space : continuous_spaces_) { 1071 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1072 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1073 stream << space << " " << *space << "\n"; 1074 if (live_bitmap != nullptr) { 1075 stream << live_bitmap << " " << *live_bitmap << "\n"; 1076 } 1077 if (mark_bitmap != nullptr) { 1078 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1079 } 1080 } 1081 for (const auto& space : discontinuous_spaces_) { 1082 stream << space << " " << *space << "\n"; 1083 } 1084} 1085 1086void Heap::VerifyObjectBody(mirror::Object* obj) { 1087 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1088 return; 1089 } 1090 // Ignore early dawn of the universe verifications. 1091 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 1092 return; 1093 } 1094 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1095 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 1096 mirror::Object::ClassOffset(), false); 1097 CHECK(c != nullptr) << "Null class in object " << obj; 1098 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1099 CHECK(VerifyClassClass(c)); 1100 1101 if (verify_object_mode_ > kVerifyObjectModeFast) { 1102 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1103 if (!IsLiveObjectLocked(obj)) { 1104 DumpSpaces(); 1105 LOG(FATAL) << "Object is dead: " << obj; 1106 } 1107 } 1108} 1109 1110void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1111 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1112} 1113 1114void Heap::VerifyHeap() { 1115 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1116 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1117} 1118 1119void Heap::RecordFree(ssize_t freed_objects, ssize_t freed_bytes) { 1120 // Use signed comparison since freed bytes can be negative when background compaction foreground 1121 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1122 // free list backed space typically increasing memory footprint due to padding and binning. 1123 DCHECK_LE(freed_bytes, static_cast<ssize_t>(num_bytes_allocated_.Load())); 1124 DCHECK_GE(freed_objects, 0); 1125 num_bytes_allocated_.FetchAndSub(freed_bytes); 1126 if (Runtime::Current()->HasStatsEnabled()) { 1127 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1128 thread_stats->freed_objects += freed_objects; 1129 thread_stats->freed_bytes += freed_bytes; 1130 // TODO: Do this concurrently. 1131 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1132 global_stats->freed_objects += freed_objects; 1133 global_stats->freed_bytes += freed_bytes; 1134 } 1135} 1136 1137mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1138 size_t alloc_size, size_t* bytes_allocated, 1139 size_t* usable_size, 1140 mirror::Class** klass) { 1141 mirror::Object* ptr = nullptr; 1142 bool was_default_allocator = allocator == GetCurrentAllocator(); 1143 DCHECK(klass != nullptr); 1144 SirtRef<mirror::Class> sirt_klass(self, *klass); 1145 // The allocation failed. If the GC is running, block until it completes, and then retry the 1146 // allocation. 1147 collector::GcType last_gc = WaitForGcToComplete(self); 1148 if (last_gc != collector::kGcTypeNone) { 1149 // If we were the default allocator but the allocator changed while we were suspended, 1150 // abort the allocation. 1151 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1152 *klass = sirt_klass.get(); 1153 return nullptr; 1154 } 1155 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1156 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1157 } 1158 1159 collector::GcType tried_type = next_gc_type_; 1160 if (ptr == nullptr) { 1161 const bool gc_ran = 1162 CollectGarbageInternal(tried_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1163 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1164 *klass = sirt_klass.get(); 1165 return nullptr; 1166 } 1167 if (gc_ran) { 1168 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1169 } 1170 } 1171 1172 // Loop through our different Gc types and try to Gc until we get enough free memory. 1173 for (collector::GcType gc_type : gc_plan_) { 1174 if (ptr != nullptr) { 1175 break; 1176 } 1177 if (gc_type == tried_type) { 1178 continue; 1179 } 1180 // Attempt to run the collector, if we succeed, re-try the allocation. 1181 const bool gc_ran = 1182 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1183 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1184 *klass = sirt_klass.get(); 1185 return nullptr; 1186 } 1187 if (gc_ran) { 1188 // Did we free sufficient memory for the allocation to succeed? 1189 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1190 } 1191 } 1192 // Allocations have failed after GCs; this is an exceptional state. 1193 if (ptr == nullptr) { 1194 // Try harder, growing the heap if necessary. 1195 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1196 } 1197 if (ptr == nullptr) { 1198 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1199 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1200 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1201 // OOME. 1202 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1203 << " allocation"; 1204 // TODO: Run finalization, but this may cause more allocations to occur. 1205 // We don't need a WaitForGcToComplete here either. 1206 DCHECK(!gc_plan_.empty()); 1207 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1208 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1209 *klass = sirt_klass.get(); 1210 return nullptr; 1211 } 1212 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1213 if (ptr == nullptr) { 1214 ThrowOutOfMemoryError(self, alloc_size, false); 1215 } 1216 } 1217 *klass = sirt_klass.get(); 1218 return ptr; 1219} 1220 1221void Heap::SetTargetHeapUtilization(float target) { 1222 DCHECK_GT(target, 0.0f); // asserted in Java code 1223 DCHECK_LT(target, 1.0f); 1224 target_utilization_ = target; 1225} 1226 1227size_t Heap::GetObjectsAllocated() const { 1228 size_t total = 0; 1229 for (space::AllocSpace* space : alloc_spaces_) { 1230 total += space->GetObjectsAllocated(); 1231 } 1232 return total; 1233} 1234 1235size_t Heap::GetObjectsAllocatedEver() const { 1236 return GetObjectsFreedEver() + GetObjectsAllocated(); 1237} 1238 1239size_t Heap::GetBytesAllocatedEver() const { 1240 return GetBytesFreedEver() + GetBytesAllocated(); 1241} 1242 1243class InstanceCounter { 1244 public: 1245 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1246 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1247 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1248 } 1249 static void Callback(mirror::Object* obj, void* arg) 1250 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1251 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1252 mirror::Class* instance_class = obj->GetClass(); 1253 CHECK(instance_class != nullptr); 1254 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1255 if (instance_counter->use_is_assignable_from_) { 1256 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1257 ++instance_counter->counts_[i]; 1258 } 1259 } else if (instance_class == instance_counter->classes_[i]) { 1260 ++instance_counter->counts_[i]; 1261 } 1262 } 1263 } 1264 1265 private: 1266 const std::vector<mirror::Class*>& classes_; 1267 bool use_is_assignable_from_; 1268 uint64_t* const counts_; 1269 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1270}; 1271 1272void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1273 uint64_t* counts) { 1274 // Can't do any GC in this function since this may move classes. 1275 Thread* self = Thread::Current(); 1276 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1277 InstanceCounter counter(classes, use_is_assignable_from, counts); 1278 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1279 VisitObjects(InstanceCounter::Callback, &counter); 1280 self->EndAssertNoThreadSuspension(old_cause); 1281} 1282 1283class InstanceCollector { 1284 public: 1285 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1286 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1287 : class_(c), max_count_(max_count), instances_(instances) { 1288 } 1289 static void Callback(mirror::Object* obj, void* arg) 1290 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1291 DCHECK(arg != nullptr); 1292 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1293 mirror::Class* instance_class = obj->GetClass(); 1294 if (instance_class == instance_collector->class_) { 1295 if (instance_collector->max_count_ == 0 || 1296 instance_collector->instances_.size() < instance_collector->max_count_) { 1297 instance_collector->instances_.push_back(obj); 1298 } 1299 } 1300 } 1301 1302 private: 1303 mirror::Class* class_; 1304 uint32_t max_count_; 1305 std::vector<mirror::Object*>& instances_; 1306 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1307}; 1308 1309void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1310 std::vector<mirror::Object*>& instances) { 1311 // Can't do any GC in this function since this may move classes. 1312 Thread* self = Thread::Current(); 1313 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1314 InstanceCollector collector(c, max_count, instances); 1315 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1316 VisitObjects(&InstanceCollector::Callback, &collector); 1317 self->EndAssertNoThreadSuspension(old_cause); 1318} 1319 1320class ReferringObjectsFinder { 1321 public: 1322 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1323 std::vector<mirror::Object*>& referring_objects) 1324 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1325 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1326 } 1327 1328 static void Callback(mirror::Object* obj, void* arg) 1329 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1330 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1331 } 1332 1333 // For bitmap Visit. 1334 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1335 // annotalysis on visitors. 1336 void operator()(mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1337 o->VisitReferences<true>(*this); 1338 } 1339 1340 // For Object::VisitReferences. 1341 void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const 1342 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1343 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 1344 if (ref == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1345 referring_objects_.push_back(obj); 1346 } 1347 } 1348 1349 private: 1350 mirror::Object* object_; 1351 uint32_t max_count_; 1352 std::vector<mirror::Object*>& referring_objects_; 1353 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1354}; 1355 1356void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1357 std::vector<mirror::Object*>& referring_objects) { 1358 // Can't do any GC in this function since this may move the object o. 1359 Thread* self = Thread::Current(); 1360 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1361 ReferringObjectsFinder finder(o, max_count, referring_objects); 1362 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1363 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1364 self->EndAssertNoThreadSuspension(old_cause); 1365} 1366 1367void Heap::CollectGarbage(bool clear_soft_references) { 1368 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1369 // last GC will not have necessarily been cleared. 1370 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1371} 1372 1373void Heap::TransitionCollector(CollectorType collector_type) { 1374 if (collector_type == collector_type_) { 1375 return; 1376 } 1377 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1378 << " -> " << static_cast<int>(collector_type); 1379 uint64_t start_time = NanoTime(); 1380 uint32_t before_size = GetTotalMemory(); 1381 uint32_t before_allocated = num_bytes_allocated_.Load(); 1382 ThreadList* tl = Runtime::Current()->GetThreadList(); 1383 Thread* self = Thread::Current(); 1384 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1385 Locks::mutator_lock_->AssertNotHeld(self); 1386 const bool copying_transition = 1387 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1388 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1389 // compacting_gc_disable_count_, this should rarely occurs). 1390 for (;;) { 1391 { 1392 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1393 MutexLock mu(self, *gc_complete_lock_); 1394 // Ensure there is only one GC at a time. 1395 WaitForGcToCompleteLocked(self); 1396 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1397 if (!copying_transition || disable_moving_gc_count_ == 0) { 1398 // TODO: Not hard code in semi-space collector? 1399 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1400 break; 1401 } 1402 } 1403 usleep(1000); 1404 } 1405 tl->SuspendAll(); 1406 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1407 switch (collector_type) { 1408 case kCollectorTypeSS: 1409 // Fall-through. 1410 case kCollectorTypeGSS: { 1411 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1412 CHECK(main_space_ != nullptr); 1413 Compact(temp_space_, main_space_); 1414 DCHECK(allocator_mem_map_.get() == nullptr); 1415 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1416 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1417 // RemoveSpace does not delete the removed space. 1418 space::Space* old_space = main_space_; 1419 RemoveSpace(old_space); 1420 delete old_space; 1421 break; 1422 } 1423 case kCollectorTypeMS: 1424 // Fall through. 1425 case kCollectorTypeCMS: { 1426 if (IsCompactingGC(collector_type_)) { 1427 // TODO: Use mem-map from temp space? 1428 MemMap* mem_map = allocator_mem_map_.release(); 1429 CHECK(mem_map != nullptr); 1430 size_t starting_size = kDefaultStartingSize; 1431 size_t initial_size = kDefaultInitialSize; 1432 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1433 CHECK(main_space_ == nullptr); 1434 if (kUseRosAlloc) { 1435 main_space_ = 1436 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", starting_size, 1437 initial_size, mem_map->Size(), 1438 mem_map->Size(), low_memory_mode_); 1439 } else { 1440 main_space_ = 1441 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", starting_size, 1442 initial_size, mem_map->Size(), 1443 mem_map->Size()); 1444 } 1445 main_space_->SetFootprintLimit(main_space_->Capacity()); 1446 AddSpace(main_space_); 1447 Compact(main_space_, bump_pointer_space_); 1448 } 1449 break; 1450 } 1451 default: { 1452 LOG(FATAL) << "Attempted to transition to invalid collector type " 1453 << static_cast<size_t>(collector_type); 1454 break; 1455 } 1456 } 1457 ChangeCollector(collector_type); 1458 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1459 tl->ResumeAll(); 1460 // Can't call into java code with all threads suspended. 1461 EnqueueClearedReferences(); 1462 uint64_t duration = NanoTime() - start_time; 1463 GrowForUtilization(semi_space_collector_); 1464 FinishGC(self, collector::kGcTypeFull); 1465 int32_t after_size = GetTotalMemory(); 1466 int32_t delta_size = before_size - after_size; 1467 int32_t after_allocated = num_bytes_allocated_.Load(); 1468 int32_t delta_allocated = before_allocated - after_allocated; 1469 const std::string saved_bytes_str = 1470 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1471 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1472 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1473 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1474 << PrettySize(delta_size) << " saved"; 1475} 1476 1477void Heap::ChangeCollector(CollectorType collector_type) { 1478 // TODO: Only do this with all mutators suspended to avoid races. 1479 if (collector_type != collector_type_) { 1480 collector_type_ = collector_type; 1481 gc_plan_.clear(); 1482 switch (collector_type_) { 1483 case kCollectorTypeCC: // Fall-through. 1484 case kCollectorTypeSS: // Fall-through. 1485 case kCollectorTypeGSS: { 1486 gc_plan_.push_back(collector::kGcTypeFull); 1487 if (use_tlab_) { 1488 ChangeAllocator(kAllocatorTypeTLAB); 1489 } else { 1490 ChangeAllocator(kAllocatorTypeBumpPointer); 1491 } 1492 break; 1493 } 1494 case kCollectorTypeMS: { 1495 gc_plan_.push_back(collector::kGcTypeSticky); 1496 gc_plan_.push_back(collector::kGcTypePartial); 1497 gc_plan_.push_back(collector::kGcTypeFull); 1498 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1499 break; 1500 } 1501 case kCollectorTypeCMS: { 1502 gc_plan_.push_back(collector::kGcTypeSticky); 1503 gc_plan_.push_back(collector::kGcTypePartial); 1504 gc_plan_.push_back(collector::kGcTypeFull); 1505 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1506 break; 1507 } 1508 default: { 1509 LOG(FATAL) << "Unimplemented"; 1510 } 1511 } 1512 if (IsGcConcurrent()) { 1513 concurrent_start_bytes_ = 1514 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1515 } else { 1516 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1517 } 1518 } 1519} 1520 1521// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1522class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1523 public: 1524 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1525 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1526 } 1527 1528 void BuildBins(space::ContinuousSpace* space) { 1529 bin_live_bitmap_ = space->GetLiveBitmap(); 1530 bin_mark_bitmap_ = space->GetMarkBitmap(); 1531 BinContext context; 1532 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1533 context.collector_ = this; 1534 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1535 // Note: This requires traversing the space in increasing order of object addresses. 1536 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1537 // Add the last bin which spans after the last object to the end of the space. 1538 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1539 } 1540 1541 private: 1542 struct BinContext { 1543 uintptr_t prev_; // The end of the previous object. 1544 ZygoteCompactingCollector* collector_; 1545 }; 1546 // Maps from bin sizes to locations. 1547 std::multimap<size_t, uintptr_t> bins_; 1548 // Live bitmap of the space which contains the bins. 1549 accounting::SpaceBitmap* bin_live_bitmap_; 1550 // Mark bitmap of the space which contains the bins. 1551 accounting::SpaceBitmap* bin_mark_bitmap_; 1552 1553 static void Callback(mirror::Object* obj, void* arg) 1554 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1555 DCHECK(arg != nullptr); 1556 BinContext* context = reinterpret_cast<BinContext*>(arg); 1557 ZygoteCompactingCollector* collector = context->collector_; 1558 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1559 size_t bin_size = object_addr - context->prev_; 1560 // Add the bin consisting of the end of the previous object to the start of the current object. 1561 collector->AddBin(bin_size, context->prev_); 1562 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1563 } 1564 1565 void AddBin(size_t size, uintptr_t position) { 1566 if (size != 0) { 1567 bins_.insert(std::make_pair(size, position)); 1568 } 1569 } 1570 1571 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1572 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1573 // allocator. 1574 return false; 1575 } 1576 1577 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1578 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1579 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1580 mirror::Object* forward_address; 1581 // Find the smallest bin which we can move obj in. 1582 auto it = bins_.lower_bound(object_size); 1583 if (it == bins_.end()) { 1584 // No available space in the bins, place it in the target space instead (grows the zygote 1585 // space). 1586 size_t bytes_allocated; 1587 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1588 if (to_space_live_bitmap_ != nullptr) { 1589 to_space_live_bitmap_->Set(forward_address); 1590 } else { 1591 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1592 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1593 } 1594 } else { 1595 size_t size = it->first; 1596 uintptr_t pos = it->second; 1597 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1598 forward_address = reinterpret_cast<mirror::Object*>(pos); 1599 // Set the live and mark bits so that sweeping system weaks works properly. 1600 bin_live_bitmap_->Set(forward_address); 1601 bin_mark_bitmap_->Set(forward_address); 1602 DCHECK_GE(size, object_size); 1603 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1604 } 1605 // Copy the object over to its new location. 1606 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1607 if (kUseBrooksPointer) { 1608 obj->AssertSelfBrooksPointer(); 1609 DCHECK_EQ(forward_address->GetBrooksPointer(), obj); 1610 forward_address->SetBrooksPointer(forward_address); 1611 forward_address->AssertSelfBrooksPointer(); 1612 } 1613 return forward_address; 1614 } 1615}; 1616 1617void Heap::UnBindBitmaps() { 1618 for (const auto& space : GetContinuousSpaces()) { 1619 if (space->IsContinuousMemMapAllocSpace()) { 1620 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1621 if (alloc_space->HasBoundBitmaps()) { 1622 alloc_space->UnBindBitmaps(); 1623 } 1624 } 1625 } 1626} 1627 1628void Heap::PreZygoteFork() { 1629 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1630 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1631 Thread* self = Thread::Current(); 1632 MutexLock mu(self, zygote_creation_lock_); 1633 // Try to see if we have any Zygote spaces. 1634 if (have_zygote_space_) { 1635 return; 1636 } 1637 VLOG(heap) << "Starting PreZygoteFork"; 1638 // Trim the pages at the end of the non moving space. 1639 non_moving_space_->Trim(); 1640 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1641 // Change the collector to the post zygote one. 1642 ChangeCollector(post_zygote_collector_type_); 1643 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1644 if (semi_space_collector_ != nullptr) { 1645 // Temporarily disable rosalloc verification because the zygote 1646 // compaction will mess up the rosalloc internal metadata. 1647 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1648 ZygoteCompactingCollector zygote_collector(this); 1649 zygote_collector.BuildBins(non_moving_space_); 1650 // Create a new bump pointer space which we will compact into. 1651 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1652 non_moving_space_->Limit()); 1653 // Compact the bump pointer space to a new zygote bump pointer space. 1654 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1655 zygote_collector.SetFromSpace(bump_pointer_space_); 1656 zygote_collector.SetToSpace(&target_space); 1657 zygote_collector.Run(kGcCauseCollectorTransition, false); 1658 CHECK(temp_space_->IsEmpty()); 1659 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1660 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1661 // Update the end and write out image. 1662 non_moving_space_->SetEnd(target_space.End()); 1663 non_moving_space_->SetLimit(target_space.Limit()); 1664 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1665 } 1666 // Save the old space so that we can remove it after we complete creating the zygote space. 1667 space::MallocSpace* old_alloc_space = non_moving_space_; 1668 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1669 // the remaining available space. 1670 // Remove the old space before creating the zygote space since creating the zygote space sets 1671 // the old alloc space's bitmaps to nullptr. 1672 RemoveSpace(old_alloc_space); 1673 if (collector::SemiSpace::kUseRememberedSet) { 1674 // Sanity bound check. 1675 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1676 // Remove the remembered set for the now zygote space (the old 1677 // non-moving space). Note now that we have compacted objects into 1678 // the zygote space, the data in the remembered set is no longer 1679 // needed. The zygote space will instead have a mod-union table 1680 // from this point on. 1681 RemoveRememberedSet(old_alloc_space); 1682 } 1683 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1684 low_memory_mode_, 1685 &main_space_); 1686 delete old_alloc_space; 1687 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1688 AddSpace(zygote_space, false); 1689 CHECK(main_space_ != nullptr); 1690 if (main_space_->IsRosAllocSpace()) { 1691 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1692 } else if (main_space_->IsDlMallocSpace()) { 1693 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1694 } 1695 main_space_->SetFootprintLimit(main_space_->Capacity()); 1696 AddSpace(main_space_); 1697 have_zygote_space_ = true; 1698 // Enable large object space allocations. 1699 large_object_threshold_ = kDefaultLargeObjectThreshold; 1700 // Create the zygote space mod union table. 1701 accounting::ModUnionTable* mod_union_table = 1702 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1703 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1704 AddModUnionTable(mod_union_table); 1705 if (collector::SemiSpace::kUseRememberedSet) { 1706 // Add a new remembered set for the new main space. 1707 accounting::RememberedSet* main_space_rem_set = 1708 new accounting::RememberedSet("Main space remembered set", this, main_space_); 1709 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 1710 AddRememberedSet(main_space_rem_set); 1711 } 1712 // Can't use RosAlloc for non moving space due to thread local buffers. 1713 // TODO: Non limited space for non-movable objects? 1714 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1715 space::MallocSpace* new_non_moving_space = 1716 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1717 2 * MB, mem_map->Size(), mem_map->Size()); 1718 AddSpace(new_non_moving_space, false); 1719 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1720 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1721 non_moving_space_ = new_non_moving_space; 1722 if (collector::SemiSpace::kUseRememberedSet) { 1723 // Add a new remembered set for the post-zygote non-moving space. 1724 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1725 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1726 non_moving_space_); 1727 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1728 << "Failed to create post-zygote non-moving space remembered set"; 1729 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1730 } 1731} 1732 1733void Heap::FlushAllocStack() { 1734 MarkAllocStackAsLive(allocation_stack_.get()); 1735 allocation_stack_->Reset(); 1736} 1737 1738void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1739 accounting::SpaceBitmap* bitmap2, 1740 accounting::ObjectSet* large_objects, 1741 accounting::ObjectStack* stack) { 1742 DCHECK(bitmap1 != nullptr); 1743 DCHECK(bitmap2 != nullptr); 1744 mirror::Object** limit = stack->End(); 1745 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1746 const mirror::Object* obj = *it; 1747 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1748 if (bitmap1->HasAddress(obj)) { 1749 bitmap1->Set(obj); 1750 } else if (bitmap2->HasAddress(obj)) { 1751 bitmap2->Set(obj); 1752 } else { 1753 large_objects->Set(obj); 1754 } 1755 } 1756 } 1757} 1758 1759void Heap::SwapSemiSpaces() { 1760 // Swap the spaces so we allocate into the space which we just evacuated. 1761 std::swap(bump_pointer_space_, temp_space_); 1762 bump_pointer_space_->Clear(); 1763} 1764 1765void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1766 space::ContinuousMemMapAllocSpace* source_space) { 1767 CHECK(kMovingCollector); 1768 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1769 if (target_space != source_space) { 1770 semi_space_collector_->SetFromSpace(source_space); 1771 semi_space_collector_->SetToSpace(target_space); 1772 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1773 } 1774} 1775 1776collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1777 bool clear_soft_references) { 1778 Thread* self = Thread::Current(); 1779 Runtime* runtime = Runtime::Current(); 1780 // If the heap can't run the GC, silently fail and return that no GC was run. 1781 switch (gc_type) { 1782 case collector::kGcTypePartial: { 1783 if (!have_zygote_space_) { 1784 return collector::kGcTypeNone; 1785 } 1786 break; 1787 } 1788 default: { 1789 // Other GC types don't have any special cases which makes them not runnable. The main case 1790 // here is full GC. 1791 } 1792 } 1793 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1794 Locks::mutator_lock_->AssertNotHeld(self); 1795 if (self->IsHandlingStackOverflow()) { 1796 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1797 } 1798 bool compacting_gc; 1799 { 1800 gc_complete_lock_->AssertNotHeld(self); 1801 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1802 MutexLock mu(self, *gc_complete_lock_); 1803 // Ensure there is only one GC at a time. 1804 WaitForGcToCompleteLocked(self); 1805 compacting_gc = IsCompactingGC(collector_type_); 1806 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1807 if (compacting_gc && disable_moving_gc_count_ != 0) { 1808 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1809 return collector::kGcTypeNone; 1810 } 1811 collector_type_running_ = collector_type_; 1812 } 1813 1814 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1815 ++runtime->GetStats()->gc_for_alloc_count; 1816 ++self->GetStats()->gc_for_alloc_count; 1817 } 1818 uint64_t gc_start_time_ns = NanoTime(); 1819 uint64_t gc_start_size = GetBytesAllocated(); 1820 // Approximate allocation rate in bytes / second. 1821 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1822 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1823 if (LIKELY(ms_delta != 0)) { 1824 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1825 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1826 } 1827 1828 DCHECK_LT(gc_type, collector::kGcTypeMax); 1829 DCHECK_NE(gc_type, collector::kGcTypeNone); 1830 1831 collector::GarbageCollector* collector = nullptr; 1832 // TODO: Clean this up. 1833 if (compacting_gc) { 1834 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1835 current_allocator_ == kAllocatorTypeTLAB); 1836 if (collector_type_ == kCollectorTypeSS || collector_type_ == kCollectorTypeGSS) { 1837 gc_type = semi_space_collector_->GetGcType(); 1838 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1839 semi_space_collector_->SetToSpace(temp_space_); 1840 collector = semi_space_collector_; 1841 } else if (collector_type_ == kCollectorTypeCC) { 1842 gc_type = concurrent_copying_collector_->GetGcType(); 1843 collector = concurrent_copying_collector_; 1844 } else { 1845 LOG(FATAL) << "Unreachable - invalid collector type " << static_cast<size_t>(collector_type_); 1846 } 1847 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1848 CHECK(temp_space_->IsEmpty()); 1849 gc_type = collector::kGcTypeFull; 1850 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1851 current_allocator_ == kAllocatorTypeDlMalloc) { 1852 collector = FindCollectorByGcType(gc_type); 1853 } else { 1854 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1855 } 1856 CHECK(collector != nullptr) 1857 << "Could not find garbage collector with collector_type=" 1858 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1859 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1860 if (!clear_soft_references) { 1861 clear_soft_references = gc_type != collector::kGcTypeSticky; // TODO: GSS? 1862 } 1863 collector->Run(gc_cause, clear_soft_references || runtime->IsZygote()); 1864 total_objects_freed_ever_ += collector->GetFreedObjects(); 1865 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1866 RequestHeapTrim(); 1867 // Enqueue cleared references. 1868 EnqueueClearedReferences(); 1869 // Grow the heap so that we know when to perform the next GC. 1870 GrowForUtilization(collector); 1871 if (CareAboutPauseTimes()) { 1872 const size_t duration = collector->GetDurationNs(); 1873 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1874 // GC for alloc pauses the allocating thread, so consider it as a pause. 1875 bool was_slow = duration > long_gc_log_threshold_ || 1876 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1877 if (!was_slow) { 1878 for (uint64_t pause : pauses) { 1879 was_slow = was_slow || pause > long_pause_log_threshold_; 1880 } 1881 } 1882 if (was_slow) { 1883 const size_t percent_free = GetPercentFree(); 1884 const size_t current_heap_size = GetBytesAllocated(); 1885 const size_t total_memory = GetTotalMemory(); 1886 std::ostringstream pause_string; 1887 for (size_t i = 0; i < pauses.size(); ++i) { 1888 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1889 << ((i != pauses.size() - 1) ? ", " : ""); 1890 } 1891 LOG(INFO) << gc_cause << " " << collector->GetName() 1892 << " GC freed " << collector->GetFreedObjects() << "(" 1893 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1894 << collector->GetFreedLargeObjects() << "(" 1895 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1896 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1897 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1898 << " total " << PrettyDuration((duration / 1000) * 1000); 1899 VLOG(heap) << ConstDumpable<TimingLogger>(collector->GetTimings()); 1900 } 1901 } 1902 FinishGC(self, gc_type); 1903 ATRACE_END(); 1904 1905 // Inform DDMS that a GC completed. 1906 Dbg::GcDidFinish(); 1907 return gc_type; 1908} 1909 1910void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1911 MutexLock mu(self, *gc_complete_lock_); 1912 collector_type_running_ = kCollectorTypeNone; 1913 if (gc_type != collector::kGcTypeNone) { 1914 last_gc_type_ = gc_type; 1915 } 1916 // Wake anyone who may have been waiting for the GC to complete. 1917 gc_complete_cond_->Broadcast(self); 1918} 1919 1920static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1921 RootType /*root_type*/) { 1922 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1923 if (*root == obj) { 1924 LOG(INFO) << "Object " << obj << " is a root"; 1925 } 1926} 1927 1928class ScanVisitor { 1929 public: 1930 void operator()(const mirror::Object* obj) const { 1931 LOG(ERROR) << "Would have rescanned object " << obj; 1932 } 1933}; 1934 1935// Verify a reference from an object. 1936class VerifyReferenceVisitor { 1937 public: 1938 explicit VerifyReferenceVisitor(Heap* heap) 1939 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1940 : heap_(heap), failed_(false) {} 1941 1942 bool Failed() const { 1943 return failed_; 1944 } 1945 1946 void operator()(mirror::Class* klass, mirror::Reference* ref) const 1947 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1948 this->operator()(ref, mirror::Reference::ReferentOffset(), false); 1949 } 1950 1951 void operator()(mirror::Object* obj, MemberOffset offset, bool /*is_static*/) const 1952 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1953 this->operator()(obj, obj->GetFieldObject<mirror::Object>(offset, false), offset); 1954 } 1955 1956 // TODO: Fix the no thread safety analysis. 1957 void operator()(mirror::Object* obj, mirror::Object* ref, MemberOffset offset) const 1958 NO_THREAD_SAFETY_ANALYSIS { 1959 if (ref == nullptr || IsLive(ref)) { 1960 // Verify that the reference is live. 1961 return; 1962 } 1963 if (!failed_) { 1964 // Print message on only on first failure to prevent spam. 1965 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1966 failed_ = true; 1967 } 1968 if (obj != nullptr) { 1969 accounting::CardTable* card_table = heap_->GetCardTable(); 1970 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1971 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1972 byte* card_addr = card_table->CardFromAddr(obj); 1973 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1974 << offset << "\n card value = " << static_cast<int>(*card_addr); 1975 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1976 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1977 } else { 1978 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1979 } 1980 1981 // Attmept to find the class inside of the recently freed objects. 1982 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1983 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1984 space::MallocSpace* space = ref_space->AsMallocSpace(); 1985 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1986 if (ref_class != nullptr) { 1987 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1988 << PrettyClass(ref_class); 1989 } else { 1990 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1991 } 1992 } 1993 1994 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1995 ref->GetClass()->IsClass()) { 1996 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1997 } else { 1998 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1999 << ") is not a valid heap address"; 2000 } 2001 2002 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 2003 void* cover_begin = card_table->AddrFromCard(card_addr); 2004 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 2005 accounting::CardTable::kCardSize); 2006 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 2007 << "-" << cover_end; 2008 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 2009 2010 if (bitmap == nullptr) { 2011 LOG(ERROR) << "Object " << obj << " has no bitmap"; 2012 if (!VerifyClassClass(obj->GetClass())) { 2013 LOG(ERROR) << "Object " << obj << " failed class verification!"; 2014 } 2015 } else { 2016 // Print out how the object is live. 2017 if (bitmap->Test(obj)) { 2018 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2019 } 2020 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 2021 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 2022 } 2023 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 2024 LOG(ERROR) << "Object " << obj << " found in live stack"; 2025 } 2026 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 2027 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 2028 } 2029 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 2030 LOG(ERROR) << "Ref " << ref << " found in live stack"; 2031 } 2032 // Attempt to see if the card table missed the reference. 2033 ScanVisitor scan_visitor; 2034 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 2035 card_table->Scan(bitmap, byte_cover_begin, 2036 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 2037 } 2038 2039 // Search to see if any of the roots reference our object. 2040 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 2041 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2042 2043 // Search to see if any of the roots reference our reference. 2044 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2045 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2046 } else { 2047 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 2048 } 2049 } 2050 2051 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2052 return heap_->IsLiveObjectLocked(obj, true, false, true); 2053 } 2054 2055 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2056 RootType /*root_type*/) { 2057 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2058 (*visitor)(nullptr, *root, MemberOffset(0)); 2059 } 2060 2061 private: 2062 Heap* const heap_; 2063 mutable bool failed_; 2064}; 2065 2066// Verify all references within an object, for use with HeapBitmap::Visit. 2067class VerifyObjectVisitor { 2068 public: 2069 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 2070 2071 void operator()(mirror::Object* obj) const 2072 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2073 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2074 // be live or else how did we find it in the live bitmap? 2075 VerifyReferenceVisitor visitor(heap_); 2076 // The class doesn't count as a reference but we should verify it anyways. 2077 obj->VisitReferences<true>(visitor, visitor); 2078 failed_ = failed_ || visitor.Failed(); 2079 } 2080 2081 static void VisitCallback(mirror::Object* obj, void* arg) 2082 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2083 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2084 visitor->operator()(obj); 2085 } 2086 2087 bool Failed() const { 2088 return failed_; 2089 } 2090 2091 private: 2092 Heap* const heap_; 2093 mutable bool failed_; 2094}; 2095 2096// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2097bool Heap::VerifyHeapReferences() { 2098 Thread* self = Thread::Current(); 2099 Locks::mutator_lock_->AssertExclusiveHeld(self); 2100 // Lets sort our allocation stacks so that we can efficiently binary search them. 2101 allocation_stack_->Sort(); 2102 live_stack_->Sort(); 2103 // Since we sorted the allocation stack content, need to revoke all 2104 // thread-local allocation stacks. 2105 RevokeAllThreadLocalAllocationStacks(self); 2106 VerifyObjectVisitor visitor(this); 2107 // Verify objects in the allocation stack since these will be objects which were: 2108 // 1. Allocated prior to the GC (pre GC verification). 2109 // 2. Allocated during the GC (pre sweep GC verification). 2110 // We don't want to verify the objects in the live stack since they themselves may be 2111 // pointing to dead objects if they are not reachable. 2112 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2113 // Verify the roots: 2114 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor); 2115 if (visitor.Failed()) { 2116 // Dump mod-union tables. 2117 for (const auto& table_pair : mod_union_tables_) { 2118 accounting::ModUnionTable* mod_union_table = table_pair.second; 2119 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2120 } 2121 // Dump remembered sets. 2122 for (const auto& table_pair : remembered_sets_) { 2123 accounting::RememberedSet* remembered_set = table_pair.second; 2124 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2125 } 2126 DumpSpaces(); 2127 return false; 2128 } 2129 return true; 2130} 2131 2132class VerifyReferenceCardVisitor { 2133 public: 2134 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2135 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2136 Locks::heap_bitmap_lock_) 2137 : heap_(heap), failed_(failed) { 2138 } 2139 2140 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2141 // annotalysis on visitors. 2142 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static) const 2143 NO_THREAD_SAFETY_ANALYSIS { 2144 mirror::Object* ref = obj->GetFieldObject<mirror::Object>(offset, false); 2145 // Filter out class references since changing an object's class does not mark the card as dirty. 2146 // Also handles large objects, since the only reference they hold is a class reference. 2147 if (ref != nullptr && !ref->IsClass()) { 2148 accounting::CardTable* card_table = heap_->GetCardTable(); 2149 // If the object is not dirty and it is referencing something in the live stack other than 2150 // class, then it must be on a dirty card. 2151 if (!card_table->AddrIsInCardTable(obj)) { 2152 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2153 *failed_ = true; 2154 } else if (!card_table->IsDirty(obj)) { 2155 // TODO: Check mod-union tables. 2156 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2157 // kCardDirty - 1 if it didnt get touched since we aged it. 2158 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2159 if (live_stack->ContainsSorted(ref)) { 2160 if (live_stack->ContainsSorted(obj)) { 2161 LOG(ERROR) << "Object " << obj << " found in live stack"; 2162 } 2163 if (heap_->GetLiveBitmap()->Test(obj)) { 2164 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2165 } 2166 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2167 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2168 2169 // Print which field of the object is dead. 2170 if (!obj->IsObjectArray()) { 2171 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2172 CHECK(klass != NULL); 2173 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2174 : klass->GetIFields(); 2175 CHECK(fields != NULL); 2176 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2177 mirror::ArtField* cur = fields->Get(i); 2178 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2179 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2180 << PrettyField(cur); 2181 break; 2182 } 2183 } 2184 } else { 2185 mirror::ObjectArray<mirror::Object>* object_array = 2186 obj->AsObjectArray<mirror::Object>(); 2187 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2188 if (object_array->Get(i) == ref) { 2189 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2190 } 2191 } 2192 } 2193 2194 *failed_ = true; 2195 } 2196 } 2197 } 2198 } 2199 2200 private: 2201 Heap* const heap_; 2202 bool* const failed_; 2203}; 2204 2205class VerifyLiveStackReferences { 2206 public: 2207 explicit VerifyLiveStackReferences(Heap* heap) 2208 : heap_(heap), 2209 failed_(false) {} 2210 2211 void operator()(mirror::Object* obj) const 2212 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2213 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2214 obj->VisitReferences<true>(visitor); 2215 } 2216 2217 bool Failed() const { 2218 return failed_; 2219 } 2220 2221 private: 2222 Heap* const heap_; 2223 bool failed_; 2224}; 2225 2226bool Heap::VerifyMissingCardMarks() { 2227 Thread* self = Thread::Current(); 2228 Locks::mutator_lock_->AssertExclusiveHeld(self); 2229 2230 // We need to sort the live stack since we binary search it. 2231 live_stack_->Sort(); 2232 // Since we sorted the allocation stack content, need to revoke all 2233 // thread-local allocation stacks. 2234 RevokeAllThreadLocalAllocationStacks(self); 2235 VerifyLiveStackReferences visitor(this); 2236 GetLiveBitmap()->Visit(visitor); 2237 2238 // We can verify objects in the live stack since none of these should reference dead objects. 2239 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2240 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2241 visitor(*it); 2242 } 2243 } 2244 2245 if (visitor.Failed()) { 2246 DumpSpaces(); 2247 return false; 2248 } 2249 return true; 2250} 2251 2252void Heap::SwapStacks(Thread* self) { 2253 if (kUseThreadLocalAllocationStack) { 2254 live_stack_->AssertAllZero(); 2255 } 2256 allocation_stack_.swap(live_stack_); 2257} 2258 2259void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2260 // This must be called only during the pause. 2261 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2262 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2263 MutexLock mu2(self, *Locks::thread_list_lock_); 2264 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2265 for (Thread* t : thread_list) { 2266 t->RevokeThreadLocalAllocationStack(); 2267 } 2268} 2269 2270void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2271 if (kIsDebugBuild) { 2272 if (bump_pointer_space_ != nullptr) { 2273 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2274 } 2275 } 2276} 2277 2278accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2279 auto it = mod_union_tables_.find(space); 2280 if (it == mod_union_tables_.end()) { 2281 return nullptr; 2282 } 2283 return it->second; 2284} 2285 2286accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2287 auto it = remembered_sets_.find(space); 2288 if (it == remembered_sets_.end()) { 2289 return nullptr; 2290 } 2291 return it->second; 2292} 2293 2294void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2295 // Clear cards and keep track of cards cleared in the mod-union table. 2296 for (const auto& space : continuous_spaces_) { 2297 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2298 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2299 if (table != nullptr) { 2300 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2301 "ImageModUnionClearCards"; 2302 TimingLogger::ScopedSplit split(name, &timings); 2303 table->ClearCards(); 2304 } else if (use_rem_sets && rem_set != nullptr) { 2305 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2306 << static_cast<int>(collector_type_); 2307 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2308 rem_set->ClearCards(); 2309 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2310 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2311 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2312 // were dirty before the GC started. 2313 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2314 // -> clean(cleaning thread). 2315 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2316 // roots and then we scan / update mod union tables after. We will always scan either card. 2317 // If we end up with the non aged card, we scan it it in the pause. 2318 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2319 } 2320 } 2321} 2322 2323static void IdentityMarkHeapReferenceCallback(mirror::HeapReference<mirror::Object>*, void*) { 2324} 2325 2326void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2327 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2328 Thread* self = Thread::Current(); 2329 2330 if (verify_pre_gc_heap_) { 2331 thread_list->SuspendAll(); 2332 { 2333 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2334 if (!VerifyHeapReferences()) { 2335 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2336 } 2337 } 2338 thread_list->ResumeAll(); 2339 } 2340 2341 // Check that all objects which reference things in the live stack are on dirty cards. 2342 if (verify_missing_card_marks_) { 2343 thread_list->SuspendAll(); 2344 { 2345 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2346 SwapStacks(self); 2347 // Sort the live stack so that we can quickly binary search it later. 2348 if (!VerifyMissingCardMarks()) { 2349 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2350 } 2351 SwapStacks(self); 2352 } 2353 thread_list->ResumeAll(); 2354 } 2355 2356 if (verify_mod_union_table_) { 2357 thread_list->SuspendAll(); 2358 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2359 for (const auto& table_pair : mod_union_tables_) { 2360 accounting::ModUnionTable* mod_union_table = table_pair.second; 2361 mod_union_table->UpdateAndMarkReferences(IdentityMarkHeapReferenceCallback, nullptr); 2362 mod_union_table->Verify(); 2363 } 2364 thread_list->ResumeAll(); 2365 } 2366} 2367 2368void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2369 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2370 // reachable objects. 2371 if (verify_post_gc_heap_) { 2372 Thread* self = Thread::Current(); 2373 CHECK_NE(self->GetState(), kRunnable); 2374 { 2375 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2376 // Swapping bound bitmaps does nothing. 2377 gc->SwapBitmaps(); 2378 if (!VerifyHeapReferences()) { 2379 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2380 } 2381 gc->SwapBitmaps(); 2382 } 2383 } 2384} 2385 2386void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2387 if (verify_system_weaks_) { 2388 Thread* self = Thread::Current(); 2389 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2390 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2391 mark_sweep->VerifySystemWeaks(); 2392 } 2393} 2394 2395void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2396 if (verify_pre_gc_rosalloc_) { 2397 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2398 for (const auto& space : continuous_spaces_) { 2399 if (space->IsRosAllocSpace()) { 2400 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2401 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2402 rosalloc_space->Verify(); 2403 } 2404 } 2405 } 2406} 2407 2408void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2409 if (verify_post_gc_rosalloc_) { 2410 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2411 for (const auto& space : continuous_spaces_) { 2412 if (space->IsRosAllocSpace()) { 2413 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2414 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2415 rosalloc_space->Verify(); 2416 } 2417 } 2418 } 2419} 2420 2421collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2422 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2423 MutexLock mu(self, *gc_complete_lock_); 2424 return WaitForGcToCompleteLocked(self); 2425} 2426 2427collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2428 collector::GcType last_gc_type = collector::kGcTypeNone; 2429 uint64_t wait_start = NanoTime(); 2430 while (collector_type_running_ != kCollectorTypeNone) { 2431 ATRACE_BEGIN("GC: Wait For Completion"); 2432 // We must wait, change thread state then sleep on gc_complete_cond_; 2433 gc_complete_cond_->Wait(self); 2434 last_gc_type = last_gc_type_; 2435 ATRACE_END(); 2436 } 2437 uint64_t wait_time = NanoTime() - wait_start; 2438 total_wait_time_ += wait_time; 2439 if (wait_time > long_pause_log_threshold_) { 2440 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2441 } 2442 return last_gc_type; 2443} 2444 2445void Heap::DumpForSigQuit(std::ostream& os) { 2446 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2447 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2448 DumpGcPerformanceInfo(os); 2449} 2450 2451size_t Heap::GetPercentFree() { 2452 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2453} 2454 2455void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2456 if (max_allowed_footprint > GetMaxMemory()) { 2457 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2458 << PrettySize(GetMaxMemory()); 2459 max_allowed_footprint = GetMaxMemory(); 2460 } 2461 max_allowed_footprint_ = max_allowed_footprint; 2462} 2463 2464bool Heap::IsMovableObject(const mirror::Object* obj) const { 2465 if (kMovingCollector) { 2466 DCHECK(!IsInTempSpace(obj)); 2467 if (bump_pointer_space_->HasAddress(obj)) { 2468 return true; 2469 } 2470 // TODO: Refactor this logic into the space itself? 2471 // Objects in the main space are only copied during background -> foreground transitions or 2472 // visa versa. 2473 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2474 (IsCompactingGC(background_collector_type_) || 2475 IsCompactingGC(post_zygote_collector_type_))) { 2476 return true; 2477 } 2478 } 2479 return false; 2480} 2481 2482bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2483 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2484 return true; 2485 } 2486 return false; 2487} 2488 2489void Heap::UpdateMaxNativeFootprint() { 2490 size_t native_size = native_bytes_allocated_; 2491 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2492 size_t target_size = native_size / GetTargetHeapUtilization(); 2493 if (target_size > native_size + max_free_) { 2494 target_size = native_size + max_free_; 2495 } else if (target_size < native_size + min_free_) { 2496 target_size = native_size + min_free_; 2497 } 2498 native_footprint_gc_watermark_ = target_size; 2499 native_footprint_limit_ = 2 * target_size - native_size; 2500} 2501 2502collector::GarbageCollector* Heap::FindCollectorByGcType(collector::GcType gc_type) { 2503 for (const auto& collector : garbage_collectors_) { 2504 if (collector->GetCollectorType() == collector_type_ && 2505 collector->GetGcType() == gc_type) { 2506 return collector; 2507 } 2508 } 2509 return nullptr; 2510} 2511 2512void Heap::GrowForUtilization(collector::GarbageCollector* collector_ran) { 2513 // We know what our utilization is at this moment. 2514 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2515 const size_t bytes_allocated = GetBytesAllocated(); 2516 last_gc_size_ = bytes_allocated; 2517 last_gc_time_ns_ = NanoTime(); 2518 size_t target_size; 2519 collector::GcType gc_type = collector_ran->GetGcType(); 2520 if (gc_type != collector::kGcTypeSticky) { 2521 // Grow the heap for non sticky GC. 2522 target_size = bytes_allocated / GetTargetHeapUtilization(); 2523 if (target_size > bytes_allocated + max_free_) { 2524 target_size = bytes_allocated + max_free_; 2525 } else if (target_size < bytes_allocated + min_free_) { 2526 target_size = bytes_allocated + min_free_; 2527 } 2528 native_need_to_run_finalization_ = true; 2529 next_gc_type_ = collector::kGcTypeSticky; 2530 } else { 2531 collector::GcType non_sticky_gc_type = 2532 have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2533 // Find what the next non sticky collector will be. 2534 collector::GarbageCollector* non_sticky_collector = FindCollectorByGcType(non_sticky_gc_type); 2535 // If the throughput of the current sticky GC >= throughput of the non sticky collector, then 2536 // do another sticky collection next. 2537 // We also check that the bytes allocated aren't over the footprint limit in order to prevent a 2538 // pathological case where dead objects which aren't reclaimed by sticky could get accumulated 2539 // if the sticky GC throughput always remained >= the full/partial throughput. 2540 if (collector_ran->GetEstimatedLastIterationThroughput() >= 2541 non_sticky_collector->GetEstimatedMeanThroughput() && 2542 non_sticky_collector->GetIterations() > 0 && 2543 bytes_allocated <= max_allowed_footprint_) { 2544 next_gc_type_ = collector::kGcTypeSticky; 2545 } else { 2546 next_gc_type_ = non_sticky_gc_type; 2547 } 2548 // If we have freed enough memory, shrink the heap back down. 2549 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2550 target_size = bytes_allocated + max_free_; 2551 } else { 2552 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2553 } 2554 } 2555 if (!ignore_max_footprint_) { 2556 SetIdealFootprint(target_size); 2557 if (IsGcConcurrent()) { 2558 // Calculate when to perform the next ConcurrentGC. 2559 // Calculate the estimated GC duration. 2560 const double gc_duration_seconds = NsToMs(collector_ran->GetDurationNs()) / 1000.0; 2561 // Estimate how many remaining bytes we will have when we need to start the next GC. 2562 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2563 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2564 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2565 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2566 // A never going to happen situation that from the estimated allocation rate we will exceed 2567 // the applications entire footprint with the given estimated allocation rate. Schedule 2568 // another GC nearly straight away. 2569 remaining_bytes = kMinConcurrentRemainingBytes; 2570 } 2571 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2572 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2573 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2574 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2575 // right away. 2576 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2577 } 2578 } 2579} 2580 2581void Heap::ClearGrowthLimit() { 2582 growth_limit_ = capacity_; 2583 non_moving_space_->ClearGrowthLimit(); 2584} 2585 2586void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2587 ScopedObjectAccess soa(self); 2588 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(object)); 2589 jvalue args[1]; 2590 args[0].l = arg.get(); 2591 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2592} 2593 2594void Heap::EnqueueClearedReferences() { 2595 Thread* self = Thread::Current(); 2596 Locks::mutator_lock_->AssertNotHeld(self); 2597 if (!cleared_references_.IsEmpty()) { 2598 // When a runtime isn't started there are no reference queues to care about so ignore. 2599 if (LIKELY(Runtime::Current()->IsStarted())) { 2600 ScopedObjectAccess soa(self); 2601 ScopedLocalRef<jobject> arg(self->GetJniEnv(), 2602 soa.AddLocalReference<jobject>(cleared_references_.GetList())); 2603 jvalue args[1]; 2604 args[0].l = arg.get(); 2605 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_ReferenceQueue_add, args); 2606 } 2607 cleared_references_.Clear(); 2608 } 2609} 2610 2611void Heap::RequestConcurrentGC(Thread* self) { 2612 // Make sure that we can do a concurrent GC. 2613 Runtime* runtime = Runtime::Current(); 2614 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2615 self->IsHandlingStackOverflow()) { 2616 return; 2617 } 2618 // We already have a request pending, no reason to start more until we update 2619 // concurrent_start_bytes_. 2620 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2621 JNIEnv* env = self->GetJniEnv(); 2622 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2623 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2624 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2625 WellKnownClasses::java_lang_Daemons_requestGC); 2626 CHECK(!env->ExceptionCheck()); 2627} 2628 2629void Heap::ConcurrentGC(Thread* self) { 2630 if (Runtime::Current()->IsShuttingDown(self)) { 2631 return; 2632 } 2633 // Wait for any GCs currently running to finish. 2634 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2635 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2636 // instead. E.g. can't do partial, so do full instead. 2637 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2638 collector::kGcTypeNone) { 2639 for (collector::GcType gc_type : gc_plan_) { 2640 // Attempt to run the collector, if we succeed, we are done. 2641 if (gc_type > next_gc_type_ && 2642 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2643 break; 2644 } 2645 } 2646 } 2647 } 2648} 2649 2650void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2651 Thread* self = Thread::Current(); 2652 { 2653 MutexLock mu(self, *heap_trim_request_lock_); 2654 if (desired_collector_type_ == desired_collector_type) { 2655 return; 2656 } 2657 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2658 desired_collector_type_ = desired_collector_type; 2659 } 2660 SignalHeapTrimDaemon(self); 2661} 2662 2663void Heap::RequestHeapTrim() { 2664 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2665 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2666 // a space it will hold its lock and can become a cause of jank. 2667 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2668 // forking. 2669 2670 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2671 // because that only marks object heads, so a large array looks like lots of empty space. We 2672 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2673 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2674 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2675 // not how much use we're making of those pages. 2676 2677 Thread* self = Thread::Current(); 2678 Runtime* runtime = Runtime::Current(); 2679 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2680 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2681 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2682 // as we don't hold the lock while requesting the trim). 2683 return; 2684 } 2685 2686 // Request a heap trim only if we do not currently care about pause times. 2687 if (!CareAboutPauseTimes()) { 2688 { 2689 MutexLock mu(self, *heap_trim_request_lock_); 2690 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2691 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2692 // just yet. 2693 return; 2694 } 2695 heap_trim_request_pending_ = true; 2696 } 2697 // Notify the daemon thread which will actually do the heap trim. 2698 SignalHeapTrimDaemon(self); 2699 } 2700} 2701 2702void Heap::SignalHeapTrimDaemon(Thread* self) { 2703 JNIEnv* env = self->GetJniEnv(); 2704 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2705 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2706 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2707 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2708 CHECK(!env->ExceptionCheck()); 2709} 2710 2711void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2712 if (rosalloc_space_ != nullptr) { 2713 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2714 } 2715 if (bump_pointer_space_ != nullptr) { 2716 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2717 } 2718} 2719 2720void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2721 if (rosalloc_space_ != nullptr) { 2722 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2723 } 2724} 2725 2726void Heap::RevokeAllThreadLocalBuffers() { 2727 if (rosalloc_space_ != nullptr) { 2728 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2729 } 2730 if (bump_pointer_space_ != nullptr) { 2731 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2732 } 2733} 2734 2735bool Heap::IsGCRequestPending() const { 2736 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2737} 2738 2739void Heap::RunFinalization(JNIEnv* env) { 2740 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2741 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2742 CHECK(WellKnownClasses::java_lang_System != nullptr); 2743 WellKnownClasses::java_lang_System_runFinalization = 2744 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2745 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2746 } 2747 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2748 WellKnownClasses::java_lang_System_runFinalization); 2749} 2750 2751void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2752 Thread* self = ThreadForEnv(env); 2753 if (native_need_to_run_finalization_) { 2754 RunFinalization(env); 2755 UpdateMaxNativeFootprint(); 2756 native_need_to_run_finalization_ = false; 2757 } 2758 // Total number of native bytes allocated. 2759 native_bytes_allocated_.FetchAndAdd(bytes); 2760 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2761 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2762 collector::kGcTypeFull; 2763 2764 // The second watermark is higher than the gc watermark. If you hit this it means you are 2765 // allocating native objects faster than the GC can keep up with. 2766 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2767 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2768 // Just finished a GC, attempt to run finalizers. 2769 RunFinalization(env); 2770 CHECK(!env->ExceptionCheck()); 2771 } 2772 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2773 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2774 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2775 RunFinalization(env); 2776 native_need_to_run_finalization_ = false; 2777 CHECK(!env->ExceptionCheck()); 2778 } 2779 // We have just run finalizers, update the native watermark since it is very likely that 2780 // finalizers released native managed allocations. 2781 UpdateMaxNativeFootprint(); 2782 } else if (!IsGCRequestPending()) { 2783 if (IsGcConcurrent()) { 2784 RequestConcurrentGC(self); 2785 } else { 2786 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2787 } 2788 } 2789 } 2790} 2791 2792void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2793 int expected_size, new_size; 2794 do { 2795 expected_size = native_bytes_allocated_.Load(); 2796 new_size = expected_size - bytes; 2797 if (UNLIKELY(new_size < 0)) { 2798 ScopedObjectAccess soa(env); 2799 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2800 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2801 "registered as allocated", bytes, expected_size).c_str()); 2802 break; 2803 } 2804 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2805} 2806 2807size_t Heap::GetTotalMemory() const { 2808 size_t ret = 0; 2809 for (const auto& space : continuous_spaces_) { 2810 // Currently don't include the image space. 2811 if (!space->IsImageSpace()) { 2812 ret += space->Size(); 2813 } 2814 } 2815 for (const auto& space : discontinuous_spaces_) { 2816 if (space->IsLargeObjectSpace()) { 2817 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2818 } 2819 } 2820 return ret; 2821} 2822 2823void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2824 DCHECK(mod_union_table != nullptr); 2825 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2826} 2827 2828void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2829 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2830 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2831 strlen(ClassHelper(c).GetDescriptor()) == 0); 2832 CHECK_GE(byte_count, sizeof(mirror::Object)); 2833} 2834 2835void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2836 CHECK(remembered_set != nullptr); 2837 space::Space* space = remembered_set->GetSpace(); 2838 CHECK(space != nullptr); 2839 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2840 remembered_sets_.Put(space, remembered_set); 2841 CHECK(remembered_sets_.find(space) != remembered_sets_.end()); 2842} 2843 2844void Heap::RemoveRememberedSet(space::Space* space) { 2845 CHECK(space != nullptr); 2846 auto it = remembered_sets_.find(space); 2847 CHECK(it != remembered_sets_.end()); 2848 remembered_sets_.erase(it); 2849 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2850} 2851 2852void Heap::ClearMarkedObjects() { 2853 // Clear all of the spaces' mark bitmaps. 2854 for (const auto& space : GetContinuousSpaces()) { 2855 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 2856 if (space->GetLiveBitmap() != mark_bitmap) { 2857 mark_bitmap->Clear(); 2858 } 2859 } 2860 // Clear the marked objects in the discontinous space object sets. 2861 for (const auto& space : GetDiscontinuousSpaces()) { 2862 space->GetMarkObjects()->Clear(); 2863 } 2864} 2865 2866} // namespace gc 2867} // namespace art 2868