heap.cc revision c93c530efc175954160c3834c93961a1a946a35a
1/* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "heap.h" 18 19#define ATRACE_TAG ATRACE_TAG_DALVIK 20#include <cutils/trace.h> 21 22#include <limits> 23#include <vector> 24#include <valgrind.h> 25 26#include "base/histogram-inl.h" 27#include "base/stl_util.h" 28#include "common_throws.h" 29#include "cutils/sched_policy.h" 30#include "debugger.h" 31#include "gc/accounting/atomic_stack.h" 32#include "gc/accounting/card_table-inl.h" 33#include "gc/accounting/heap_bitmap-inl.h" 34#include "gc/accounting/mod_union_table.h" 35#include "gc/accounting/mod_union_table-inl.h" 36#include "gc/accounting/remembered_set.h" 37#include "gc/accounting/space_bitmap-inl.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 bool kGCALotMode = false; 74static constexpr size_t kGcAlotInterval = KB; 75// Minimum amount of remaining bytes before a concurrent GC is triggered. 76static constexpr size_t kMinConcurrentRemainingBytes = 128 * KB; 77static constexpr size_t kMaxConcurrentRemainingBytes = 512 * KB; 78 79Heap::Heap(size_t initial_size, size_t growth_limit, size_t min_free, size_t max_free, 80 double target_utilization, size_t capacity, const std::string& image_file_name, 81 CollectorType post_zygote_collector_type, CollectorType background_collector_type, 82 size_t parallel_gc_threads, size_t conc_gc_threads, bool low_memory_mode, 83 size_t long_pause_log_threshold, size_t long_gc_log_threshold, 84 bool ignore_max_footprint, bool use_tlab, bool verify_pre_gc_heap, 85 bool verify_post_gc_heap, bool verify_pre_gc_rosalloc, 86 bool verify_post_gc_rosalloc) 87 : non_moving_space_(nullptr), 88 rosalloc_space_(nullptr), 89 dlmalloc_space_(nullptr), 90 main_space_(nullptr), 91 collector_type_(kCollectorTypeNone), 92 post_zygote_collector_type_(post_zygote_collector_type), 93 background_collector_type_(background_collector_type), 94 desired_collector_type_(collector_type_), 95 heap_trim_request_lock_(nullptr), 96 last_trim_time_(0), 97 heap_transition_target_time_(0), 98 heap_trim_request_pending_(false), 99 parallel_gc_threads_(parallel_gc_threads), 100 conc_gc_threads_(conc_gc_threads), 101 low_memory_mode_(low_memory_mode), 102 long_pause_log_threshold_(long_pause_log_threshold), 103 long_gc_log_threshold_(long_gc_log_threshold), 104 ignore_max_footprint_(ignore_max_footprint), 105 have_zygote_space_(false), 106 large_object_threshold_(std::numeric_limits<size_t>::max()), // Starts out disabled. 107 collector_type_running_(kCollectorTypeNone), 108 last_gc_type_(collector::kGcTypeNone), 109 next_gc_type_(collector::kGcTypePartial), 110 capacity_(capacity), 111 growth_limit_(growth_limit), 112 max_allowed_footprint_(initial_size), 113 native_footprint_gc_watermark_(initial_size), 114 native_footprint_limit_(2 * initial_size), 115 native_need_to_run_finalization_(false), 116 // Initially assume we perceive jank in case the process state is never updated. 117 process_state_(kProcessStateJankPerceptible), 118 concurrent_start_bytes_(std::numeric_limits<size_t>::max()), 119 total_bytes_freed_ever_(0), 120 total_objects_freed_ever_(0), 121 num_bytes_allocated_(0), 122 native_bytes_allocated_(0), 123 gc_memory_overhead_(0), 124 verify_missing_card_marks_(false), 125 verify_system_weaks_(false), 126 verify_pre_gc_heap_(verify_pre_gc_heap), 127 verify_post_gc_heap_(verify_post_gc_heap), 128 verify_mod_union_table_(false), 129 verify_pre_gc_rosalloc_(verify_pre_gc_rosalloc), 130 verify_post_gc_rosalloc_(verify_post_gc_rosalloc), 131 allocation_rate_(0), 132 /* For GC a lot mode, we limit the allocations stacks to be kGcAlotInterval allocations. This 133 * causes a lot of GC since we do a GC for alloc whenever the stack is full. When heap 134 * verification is enabled, we limit the size of allocation stacks to speed up their 135 * searching. 136 */ 137 max_allocation_stack_size_(kGCALotMode ? kGcAlotInterval 138 : (kVerifyObjectSupport > kVerifyObjectModeFast) ? KB : MB), 139 current_allocator_(kAllocatorTypeDlMalloc), 140 current_non_moving_allocator_(kAllocatorTypeNonMoving), 141 bump_pointer_space_(nullptr), 142 temp_space_(nullptr), 143 min_free_(min_free), 144 max_free_(max_free), 145 target_utilization_(target_utilization), 146 total_wait_time_(0), 147 total_allocation_time_(0), 148 verify_object_mode_(kVerifyObjectModeDisabled), 149 disable_moving_gc_count_(0), 150 running_on_valgrind_(RUNNING_ON_VALGRIND > 0), 151 use_tlab_(use_tlab) { 152 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 153 LOG(INFO) << "Heap() entering"; 154 } 155 const bool is_zygote = Runtime::Current()->IsZygote(); 156 // If we aren't the zygote, switch to the default non zygote allocator. This may update the 157 // entrypoints. 158 if (!is_zygote) { 159 desired_collector_type_ = post_zygote_collector_type_; 160 large_object_threshold_ = kDefaultLargeObjectThreshold; 161 } else { 162 if (kMovingCollector) { 163 // We are the zygote, use bump pointer allocation + semi space collector. 164 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 165 desired_collector_type_ = generational ? kCollectorTypeGSS : kCollectorTypeSS; 166 } else { 167 desired_collector_type_ = post_zygote_collector_type_; 168 } 169 } 170 ChangeCollector(desired_collector_type_); 171 172 live_bitmap_.reset(new accounting::HeapBitmap(this)); 173 mark_bitmap_.reset(new accounting::HeapBitmap(this)); 174 // Requested begin for the alloc space, to follow the mapped image and oat files 175 byte* requested_alloc_space_begin = nullptr; 176 if (!image_file_name.empty()) { 177 space::ImageSpace* image_space = space::ImageSpace::Create(image_file_name.c_str()); 178 CHECK(image_space != nullptr) << "Failed to create space for " << image_file_name; 179 AddSpace(image_space); 180 // Oat files referenced by image files immediately follow them in memory, ensure alloc space 181 // isn't going to get in the middle 182 byte* oat_file_end_addr = image_space->GetImageHeader().GetOatFileEnd(); 183 CHECK_GT(oat_file_end_addr, image_space->End()); 184 if (oat_file_end_addr > requested_alloc_space_begin) { 185 requested_alloc_space_begin = AlignUp(oat_file_end_addr, kPageSize); 186 } 187 } 188 MemMap* malloc_space_mem_map = nullptr; 189 const char* malloc_space_name = is_zygote ? "zygote space" : "alloc space"; 190 if (is_zygote) { 191 // Allocate a single mem map that is split into the malloc space 192 // and the post zygote non-moving space to put them adjacent. 193 size_t post_zygote_non_moving_space_size = 64 * MB; 194 size_t non_moving_spaces_size = capacity + post_zygote_non_moving_space_size; 195 std::string error_str; 196 malloc_space_mem_map = MemMap::MapAnonymous(malloc_space_name, requested_alloc_space_begin, 197 non_moving_spaces_size, PROT_READ | PROT_WRITE, 198 true, &error_str); 199 CHECK(malloc_space_mem_map != nullptr) << error_str; 200 post_zygote_non_moving_space_mem_map_.reset(malloc_space_mem_map->RemapAtEnd( 201 malloc_space_mem_map->Begin() + capacity, "post zygote non-moving space", 202 PROT_READ | PROT_WRITE, &error_str)); 203 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr) << error_str; 204 VLOG(heap) << "malloc space mem map : " << malloc_space_mem_map; 205 VLOG(heap) << "post zygote non-moving space mem map : " 206 << post_zygote_non_moving_space_mem_map_.get(); 207 } else { 208 // Allocate a mem map for the malloc space. 209 std::string error_str; 210 malloc_space_mem_map = MemMap::MapAnonymous(malloc_space_name, requested_alloc_space_begin, 211 capacity, PROT_READ | PROT_WRITE, true, &error_str); 212 CHECK(malloc_space_mem_map != nullptr) << error_str; 213 VLOG(heap) << "malloc space mem map : " << malloc_space_mem_map; 214 } 215 CHECK(malloc_space_mem_map != nullptr); 216 space::MallocSpace* malloc_space; 217 if (kUseRosAlloc) { 218 malloc_space = space::RosAllocSpace::CreateFromMemMap(malloc_space_mem_map, malloc_space_name, 219 kDefaultStartingSize, initial_size, 220 growth_limit, capacity, low_memory_mode_); 221 CHECK(malloc_space != nullptr) << "Failed to create rosalloc space"; 222 } else { 223 malloc_space = space::DlMallocSpace::CreateFromMemMap(malloc_space_mem_map, malloc_space_name, 224 kDefaultStartingSize, initial_size, 225 growth_limit, capacity); 226 CHECK(malloc_space != nullptr) << "Failed to create dlmalloc space"; 227 } 228 VLOG(heap) << "malloc_space : " << malloc_space; 229 if (kMovingCollector) { 230 // TODO: Place bump-pointer spaces somewhere to minimize size of card table. 231 // TODO: Having 3+ spaces as big as the large heap size can cause virtual memory fragmentation 232 // issues. 233 const size_t bump_pointer_space_size = std::min(malloc_space->Capacity(), 128 * MB); 234 bump_pointer_space_ = space::BumpPointerSpace::Create("Bump pointer space", 235 bump_pointer_space_size, nullptr); 236 CHECK(bump_pointer_space_ != nullptr) << "Failed to create bump pointer space"; 237 AddSpace(bump_pointer_space_); 238 temp_space_ = space::BumpPointerSpace::Create("Bump pointer space 2", bump_pointer_space_size, 239 nullptr); 240 CHECK(temp_space_ != nullptr) << "Failed to create bump pointer space"; 241 AddSpace(temp_space_); 242 VLOG(heap) << "bump_pointer_space : " << bump_pointer_space_; 243 VLOG(heap) << "temp_space : " << temp_space_; 244 } 245 non_moving_space_ = malloc_space; 246 malloc_space->SetFootprintLimit(malloc_space->Capacity()); 247 AddSpace(malloc_space); 248 249 // Allocate the large object space. 250 constexpr bool kUseFreeListSpaceForLOS = false; 251 if (kUseFreeListSpaceForLOS) { 252 large_object_space_ = space::FreeListSpace::Create("large object space", nullptr, capacity); 253 } else { 254 large_object_space_ = space::LargeObjectMapSpace::Create("large object space"); 255 } 256 CHECK(large_object_space_ != nullptr) << "Failed to create large object space"; 257 AddSpace(large_object_space_); 258 259 // Compute heap capacity. Continuous spaces are sorted in order of Begin(). 260 CHECK(!continuous_spaces_.empty()); 261 262 // Relies on the spaces being sorted. 263 byte* heap_begin = continuous_spaces_.front()->Begin(); 264 byte* heap_end = continuous_spaces_.back()->Limit(); 265 if (is_zygote) { 266 CHECK(post_zygote_non_moving_space_mem_map_.get() != nullptr); 267 heap_begin = std::min(post_zygote_non_moving_space_mem_map_->Begin(), heap_begin); 268 heap_end = std::max(post_zygote_non_moving_space_mem_map_->End(), heap_end); 269 } 270 size_t heap_capacity = heap_end - heap_begin; 271 272 // Allocate the card table. 273 card_table_.reset(accounting::CardTable::Create(heap_begin, heap_capacity)); 274 CHECK(card_table_.get() != NULL) << "Failed to create card table"; 275 276 // Card cache for now since it makes it easier for us to update the references to the copying 277 // spaces. 278 accounting::ModUnionTable* mod_union_table = 279 new accounting::ModUnionTableCardCache("Image mod-union table", this, GetImageSpace()); 280 CHECK(mod_union_table != nullptr) << "Failed to create image mod-union table"; 281 AddModUnionTable(mod_union_table); 282 283 if (collector::SemiSpace::kUseRememberedSet) { 284 accounting::RememberedSet* non_moving_space_rem_set = 285 new accounting::RememberedSet("Non-moving space remembered set", this, non_moving_space_); 286 CHECK(non_moving_space_rem_set != nullptr) << "Failed to create non-moving space remembered set"; 287 AddRememberedSet(non_moving_space_rem_set); 288 } 289 290 // TODO: Count objects in the image space here. 291 num_bytes_allocated_ = 0; 292 293 // Default mark stack size in bytes. 294 static const size_t default_mark_stack_size = 64 * KB; 295 mark_stack_.reset(accounting::ObjectStack::Create("mark stack", default_mark_stack_size)); 296 allocation_stack_.reset(accounting::ObjectStack::Create("allocation stack", 297 max_allocation_stack_size_)); 298 live_stack_.reset(accounting::ObjectStack::Create("live stack", 299 max_allocation_stack_size_)); 300 301 // It's still too early to take a lock because there are no threads yet, but we can create locks 302 // now. We don't create it earlier to make it clear that you can't use locks during heap 303 // initialization. 304 gc_complete_lock_ = new Mutex("GC complete lock"); 305 gc_complete_cond_.reset(new ConditionVariable("GC complete condition variable", 306 *gc_complete_lock_)); 307 heap_trim_request_lock_ = new Mutex("Heap trim request lock"); 308 last_gc_size_ = GetBytesAllocated(); 309 310 if (ignore_max_footprint_) { 311 SetIdealFootprint(std::numeric_limits<size_t>::max()); 312 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 313 } 314 CHECK_NE(max_allowed_footprint_, 0U); 315 316 // Create our garbage collectors. 317 for (size_t i = 0; i < 2; ++i) { 318 const bool concurrent = i != 0; 319 garbage_collectors_.push_back(new collector::MarkSweep(this, concurrent)); 320 garbage_collectors_.push_back(new collector::PartialMarkSweep(this, concurrent)); 321 garbage_collectors_.push_back(new collector::StickyMarkSweep(this, concurrent)); 322 } 323 if (kMovingCollector) { 324 // TODO: Clean this up. 325 bool generational = post_zygote_collector_type_ == kCollectorTypeGSS; 326 semi_space_collector_ = new collector::SemiSpace(this, generational); 327 garbage_collectors_.push_back(semi_space_collector_); 328 } 329 330 if (running_on_valgrind_) { 331 Runtime::Current()->GetInstrumentation()->InstrumentQuickAllocEntryPoints(); 332 } 333 334 if (VLOG_IS_ON(heap) || VLOG_IS_ON(startup)) { 335 LOG(INFO) << "Heap() exiting"; 336 } 337} 338 339void Heap::ChangeAllocator(AllocatorType allocator) { 340 if (current_allocator_ != allocator) { 341 // These two allocators are only used internally and don't have any entrypoints. 342 CHECK_NE(allocator, kAllocatorTypeLOS); 343 CHECK_NE(allocator, kAllocatorTypeNonMoving); 344 current_allocator_ = allocator; 345 MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_); 346 SetQuickAllocEntryPointsAllocator(current_allocator_); 347 Runtime::Current()->GetInstrumentation()->ResetQuickAllocEntryPoints(); 348 } 349} 350 351void Heap::DisableCompaction() { 352 if (IsCompactingGC(post_zygote_collector_type_)) { 353 post_zygote_collector_type_ = kCollectorTypeCMS; 354 } 355 if (IsCompactingGC(background_collector_type_)) { 356 background_collector_type_ = post_zygote_collector_type_; 357 } 358 TransitionCollector(post_zygote_collector_type_); 359} 360 361std::string Heap::SafeGetClassDescriptor(mirror::Class* klass) { 362 if (!IsValidContinuousSpaceObjectAddress(klass)) { 363 return StringPrintf("<non heap address klass %p>", klass); 364 } 365 mirror::Class* component_type = klass->GetComponentType<kVerifyNone>(); 366 if (IsValidContinuousSpaceObjectAddress(component_type) && klass->IsArrayClass<kVerifyNone>()) { 367 std::string result("["); 368 result += SafeGetClassDescriptor(component_type); 369 return result; 370 } else if (UNLIKELY(klass->IsPrimitive<kVerifyNone>())) { 371 return Primitive::Descriptor(klass->GetPrimitiveType<kVerifyNone>()); 372 } else if (UNLIKELY(klass->IsProxyClass<kVerifyNone>())) { 373 return Runtime::Current()->GetClassLinker()->GetDescriptorForProxy(klass); 374 } else { 375 mirror::DexCache* dex_cache = klass->GetDexCache<kVerifyNone>(); 376 if (!IsValidContinuousSpaceObjectAddress(dex_cache)) { 377 return StringPrintf("<non heap address dex_cache %p>", dex_cache); 378 } 379 const DexFile* dex_file = dex_cache->GetDexFile(); 380 uint16_t class_def_idx = klass->GetDexClassDefIndex(); 381 if (class_def_idx == DexFile::kDexNoIndex16) { 382 return "<class def not found>"; 383 } 384 const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx); 385 const DexFile::TypeId& type_id = dex_file->GetTypeId(class_def.class_idx_); 386 return dex_file->GetTypeDescriptor(type_id); 387 } 388} 389 390std::string Heap::SafePrettyTypeOf(mirror::Object* obj) { 391 if (obj == nullptr) { 392 return "null"; 393 } 394 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 395 if (klass == nullptr) { 396 return "(class=null)"; 397 } 398 std::string result(SafeGetClassDescriptor(klass)); 399 if (obj->IsClass()) { 400 result += "<" + SafeGetClassDescriptor(obj->AsClass<kVerifyNone>()) + ">"; 401 } 402 return result; 403} 404 405void Heap::DumpObject(std::ostream& stream, mirror::Object* obj) { 406 if (obj == nullptr) { 407 stream << "(obj=null)"; 408 return; 409 } 410 if (IsAligned<kObjectAlignment>(obj)) { 411 space::Space* space = nullptr; 412 // Don't use find space since it only finds spaces which actually contain objects instead of 413 // spaces which may contain objects (e.g. cleared bump pointer spaces). 414 for (const auto& cur_space : continuous_spaces_) { 415 if (cur_space->HasAddress(obj)) { 416 space = cur_space; 417 break; 418 } 419 } 420 if (space == nullptr) { 421 if (allocator_mem_map_.get() == nullptr || !allocator_mem_map_->HasAddress(obj)) { 422 stream << "obj " << obj << " not a valid heap address"; 423 return; 424 } else if (allocator_mem_map_.get() != nullptr) { 425 allocator_mem_map_->Protect(PROT_READ | PROT_WRITE); 426 } 427 } 428 // Unprotect all the spaces. 429 for (const auto& space : continuous_spaces_) { 430 mprotect(space->Begin(), space->Capacity(), PROT_READ | PROT_WRITE); 431 } 432 stream << "Object " << obj; 433 if (space != nullptr) { 434 stream << " in space " << *space; 435 } 436 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 437 stream << "\nclass=" << klass; 438 if (klass != nullptr) { 439 stream << " type= " << SafePrettyTypeOf(obj); 440 } 441 // Re-protect the address we faulted on. 442 mprotect(AlignDown(obj, kPageSize), kPageSize, PROT_NONE); 443 } 444} 445 446bool Heap::IsCompilingBoot() const { 447 for (const auto& space : continuous_spaces_) { 448 if (space->IsImageSpace() || space->IsZygoteSpace()) { 449 return false; 450 } 451 } 452 return true; 453} 454 455bool Heap::HasImageSpace() const { 456 for (const auto& space : continuous_spaces_) { 457 if (space->IsImageSpace()) { 458 return true; 459 } 460 } 461 return false; 462} 463 464void Heap::IncrementDisableMovingGC(Thread* self) { 465 // Need to do this holding the lock to prevent races where the GC is about to run / running when 466 // we attempt to disable it. 467 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 468 MutexLock mu(self, *gc_complete_lock_); 469 ++disable_moving_gc_count_; 470 if (IsCompactingGC(collector_type_running_)) { 471 WaitForGcToCompleteLocked(self); 472 } 473} 474 475void Heap::DecrementDisableMovingGC(Thread* self) { 476 MutexLock mu(self, *gc_complete_lock_); 477 CHECK_GE(disable_moving_gc_count_, 0U); 478 --disable_moving_gc_count_; 479} 480 481void Heap::UpdateProcessState(ProcessState process_state) { 482 if (process_state_ != process_state) { 483 process_state_ = process_state; 484 if (process_state_ == kProcessStateJankPerceptible) { 485 // Transition back to foreground right away to prevent jank. 486 RequestCollectorTransition(post_zygote_collector_type_, 0); 487 } else { 488 // Don't delay for debug builds since we may want to stress test the GC. 489 RequestCollectorTransition(background_collector_type_, kIsDebugBuild ? 0 : 490 kCollectorTransitionWait); 491 } 492 } 493} 494 495void Heap::CreateThreadPool() { 496 const size_t num_threads = std::max(parallel_gc_threads_, conc_gc_threads_); 497 if (num_threads != 0) { 498 thread_pool_.reset(new ThreadPool("Heap thread pool", num_threads)); 499 } 500} 501 502void Heap::VisitObjects(ObjectCallback callback, void* arg) { 503 Thread* self = Thread::Current(); 504 // GCs can move objects, so don't allow this. 505 const char* old_cause = self->StartAssertNoThreadSuspension("Visiting objects"); 506 if (bump_pointer_space_ != nullptr) { 507 // Visit objects in bump pointer space. 508 bump_pointer_space_->Walk(callback, arg); 509 } 510 // TODO: Switch to standard begin and end to use ranged a based loop. 511 for (mirror::Object** it = allocation_stack_->Begin(), **end = allocation_stack_->End(); 512 it < end; ++it) { 513 mirror::Object* obj = *it; 514 if (obj != nullptr && obj->GetClass() != nullptr) { 515 // Avoid the race condition caused by the object not yet being written into the allocation 516 // stack or the class not yet being written in the object. Or, if kUseThreadLocalAllocationStack, 517 // there can be nulls on the allocation stack. 518 callback(obj, arg); 519 } 520 } 521 GetLiveBitmap()->Walk(callback, arg); 522 self->EndAssertNoThreadSuspension(old_cause); 523} 524 525void Heap::MarkAllocStackAsLive(accounting::ObjectStack* stack) { 526 space::ContinuousSpace* space1 = rosalloc_space_ != nullptr ? rosalloc_space_ : non_moving_space_; 527 space::ContinuousSpace* space2 = dlmalloc_space_ != nullptr ? dlmalloc_space_ : non_moving_space_; 528 // This is just logic to handle a case of either not having a rosalloc or dlmalloc space. 529 // TODO: Generalize this to n bitmaps? 530 if (space1 == nullptr) { 531 DCHECK(space2 != nullptr); 532 space1 = space2; 533 } 534 if (space2 == nullptr) { 535 DCHECK(space1 != nullptr); 536 space2 = space1; 537 } 538 MarkAllocStack(space1->GetLiveBitmap(), space2->GetLiveBitmap(), 539 large_object_space_->GetLiveObjects(), stack); 540} 541 542void Heap::DeleteThreadPool() { 543 thread_pool_.reset(nullptr); 544} 545 546void Heap::AddSpace(space::Space* space, bool set_as_default) { 547 DCHECK(space != nullptr); 548 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 549 if (space->IsContinuousSpace()) { 550 DCHECK(!space->IsDiscontinuousSpace()); 551 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 552 // Continuous spaces don't necessarily have bitmaps. 553 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 554 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 555 if (live_bitmap != nullptr) { 556 DCHECK(mark_bitmap != nullptr); 557 live_bitmap_->AddContinuousSpaceBitmap(live_bitmap); 558 mark_bitmap_->AddContinuousSpaceBitmap(mark_bitmap); 559 } 560 continuous_spaces_.push_back(continuous_space); 561 if (set_as_default) { 562 if (continuous_space->IsDlMallocSpace()) { 563 dlmalloc_space_ = continuous_space->AsDlMallocSpace(); 564 } else if (continuous_space->IsRosAllocSpace()) { 565 rosalloc_space_ = continuous_space->AsRosAllocSpace(); 566 } 567 } 568 // Ensure that spaces remain sorted in increasing order of start address. 569 std::sort(continuous_spaces_.begin(), continuous_spaces_.end(), 570 [](const space::ContinuousSpace* a, const space::ContinuousSpace* b) { 571 return a->Begin() < b->Begin(); 572 }); 573 } else { 574 DCHECK(space->IsDiscontinuousSpace()); 575 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 576 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 577 live_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 578 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 579 mark_bitmap_->AddDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 580 discontinuous_spaces_.push_back(discontinuous_space); 581 } 582 if (space->IsAllocSpace()) { 583 alloc_spaces_.push_back(space->AsAllocSpace()); 584 } 585} 586 587void Heap::RemoveSpace(space::Space* space) { 588 DCHECK(space != nullptr); 589 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 590 if (space->IsContinuousSpace()) { 591 DCHECK(!space->IsDiscontinuousSpace()); 592 space::ContinuousSpace* continuous_space = space->AsContinuousSpace(); 593 // Continuous spaces don't necessarily have bitmaps. 594 accounting::SpaceBitmap* live_bitmap = continuous_space->GetLiveBitmap(); 595 accounting::SpaceBitmap* mark_bitmap = continuous_space->GetMarkBitmap(); 596 if (live_bitmap != nullptr) { 597 DCHECK(mark_bitmap != nullptr); 598 live_bitmap_->RemoveContinuousSpaceBitmap(live_bitmap); 599 mark_bitmap_->RemoveContinuousSpaceBitmap(mark_bitmap); 600 } 601 auto it = std::find(continuous_spaces_.begin(), continuous_spaces_.end(), continuous_space); 602 DCHECK(it != continuous_spaces_.end()); 603 continuous_spaces_.erase(it); 604 if (continuous_space == dlmalloc_space_) { 605 dlmalloc_space_ = nullptr; 606 } else if (continuous_space == rosalloc_space_) { 607 rosalloc_space_ = nullptr; 608 } 609 if (continuous_space == main_space_) { 610 main_space_ = nullptr; 611 } 612 } else { 613 DCHECK(space->IsDiscontinuousSpace()); 614 space::DiscontinuousSpace* discontinuous_space = space->AsDiscontinuousSpace(); 615 DCHECK(discontinuous_space->GetLiveObjects() != nullptr); 616 live_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetLiveObjects()); 617 DCHECK(discontinuous_space->GetMarkObjects() != nullptr); 618 mark_bitmap_->RemoveDiscontinuousObjectSet(discontinuous_space->GetMarkObjects()); 619 auto it = std::find(discontinuous_spaces_.begin(), discontinuous_spaces_.end(), 620 discontinuous_space); 621 DCHECK(it != discontinuous_spaces_.end()); 622 discontinuous_spaces_.erase(it); 623 } 624 if (space->IsAllocSpace()) { 625 auto it = std::find(alloc_spaces_.begin(), alloc_spaces_.end(), space->AsAllocSpace()); 626 DCHECK(it != alloc_spaces_.end()); 627 alloc_spaces_.erase(it); 628 } 629} 630 631void Heap::RegisterGCAllocation(size_t bytes) { 632 if (this != nullptr) { 633 gc_memory_overhead_.FetchAndAdd(bytes); 634 } 635} 636 637void Heap::RegisterGCDeAllocation(size_t bytes) { 638 if (this != nullptr) { 639 gc_memory_overhead_.FetchAndSub(bytes); 640 } 641} 642 643void Heap::DumpGcPerformanceInfo(std::ostream& os) { 644 // Dump cumulative timings. 645 os << "Dumping cumulative Gc timings\n"; 646 uint64_t total_duration = 0; 647 648 // Dump cumulative loggers for each GC type. 649 uint64_t total_paused_time = 0; 650 for (const auto& collector : garbage_collectors_) { 651 CumulativeLogger& logger = collector->GetCumulativeTimings(); 652 if (logger.GetTotalNs() != 0) { 653 os << Dumpable<CumulativeLogger>(logger); 654 const uint64_t total_ns = logger.GetTotalNs(); 655 const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs(); 656 double seconds = NsToMs(logger.GetTotalNs()) / 1000.0; 657 const uint64_t freed_bytes = collector->GetTotalFreedBytes(); 658 const uint64_t freed_objects = collector->GetTotalFreedObjects(); 659 Histogram<uint64_t>::CumulativeData cumulative_data; 660 collector->GetPauseHistogram().CreateHistogram(&cumulative_data); 661 collector->GetPauseHistogram().PrintConfidenceIntervals(os, 0.99, cumulative_data); 662 os << collector->GetName() << " total time: " << PrettyDuration(total_ns) << "\n" 663 << collector->GetName() << " freed: " << freed_objects 664 << " objects with total size " << PrettySize(freed_bytes) << "\n" 665 << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / " 666 << PrettySize(freed_bytes / seconds) << "/s\n"; 667 total_duration += total_ns; 668 total_paused_time += total_pause_ns; 669 } 670 } 671 uint64_t allocation_time = static_cast<uint64_t>(total_allocation_time_) * kTimeAdjust; 672 if (total_duration != 0) { 673 const double total_seconds = static_cast<double>(total_duration / 1000) / 1000000.0; 674 os << "Total time spent in GC: " << PrettyDuration(total_duration) << "\n"; 675 os << "Mean GC size throughput: " 676 << PrettySize(GetBytesFreedEver() / total_seconds) << "/s\n"; 677 os << "Mean GC object throughput: " 678 << (GetObjectsFreedEver() / total_seconds) << " objects/s\n"; 679 } 680 size_t total_objects_allocated = GetObjectsAllocatedEver(); 681 os << "Total number of allocations: " << total_objects_allocated << "\n"; 682 size_t total_bytes_allocated = GetBytesAllocatedEver(); 683 os << "Total bytes allocated " << PrettySize(total_bytes_allocated) << "\n"; 684 if (kMeasureAllocationTime) { 685 os << "Total time spent allocating: " << PrettyDuration(allocation_time) << "\n"; 686 os << "Mean allocation time: " << PrettyDuration(allocation_time / total_objects_allocated) 687 << "\n"; 688 } 689 os << "Total mutator paused time: " << PrettyDuration(total_paused_time) << "\n"; 690 os << "Total time waiting for GC to complete: " << PrettyDuration(total_wait_time_) << "\n"; 691 os << "Approximate GC data structures memory overhead: " << gc_memory_overhead_; 692} 693 694Heap::~Heap() { 695 VLOG(heap) << "Starting ~Heap()"; 696 STLDeleteElements(&garbage_collectors_); 697 // If we don't reset then the mark stack complains in its destructor. 698 allocation_stack_->Reset(); 699 live_stack_->Reset(); 700 STLDeleteValues(&mod_union_tables_); 701 STLDeleteElements(&continuous_spaces_); 702 STLDeleteElements(&discontinuous_spaces_); 703 delete gc_complete_lock_; 704 VLOG(heap) << "Finished ~Heap()"; 705} 706 707space::ContinuousSpace* Heap::FindContinuousSpaceFromObject(const mirror::Object* obj, 708 bool fail_ok) const { 709 for (const auto& space : continuous_spaces_) { 710 if (space->Contains(obj)) { 711 return space; 712 } 713 } 714 if (!fail_ok) { 715 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 716 } 717 return NULL; 718} 719 720space::DiscontinuousSpace* Heap::FindDiscontinuousSpaceFromObject(const mirror::Object* obj, 721 bool fail_ok) const { 722 for (const auto& space : discontinuous_spaces_) { 723 if (space->Contains(obj)) { 724 return space; 725 } 726 } 727 if (!fail_ok) { 728 LOG(FATAL) << "object " << reinterpret_cast<const void*>(obj) << " not inside any spaces!"; 729 } 730 return NULL; 731} 732 733space::Space* Heap::FindSpaceFromObject(const mirror::Object* obj, bool fail_ok) const { 734 space::Space* result = FindContinuousSpaceFromObject(obj, true); 735 if (result != NULL) { 736 return result; 737 } 738 return FindDiscontinuousSpaceFromObject(obj, true); 739} 740 741struct SoftReferenceArgs { 742 IsMarkedCallback* is_marked_callback_; 743 MarkObjectCallback* mark_callback_; 744 void* arg_; 745}; 746 747mirror::Object* Heap::PreserveSoftReferenceCallback(mirror::Object* obj, void* arg) { 748 SoftReferenceArgs* args = reinterpret_cast<SoftReferenceArgs*>(arg); 749 // TODO: Not preserve all soft references. 750 return args->mark_callback_(obj, args->arg_); 751} 752 753void Heap::ProcessSoftReferences(TimingLogger& timings, bool clear_soft, 754 IsMarkedCallback* is_marked_callback, 755 MarkObjectCallback* mark_object_callback, 756 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 757 // Unless required to clear soft references with white references, preserve some white referents. 758 if (!clear_soft) { 759 // Don't clear for sticky GC. 760 SoftReferenceArgs soft_reference_args; 761 soft_reference_args.is_marked_callback_ = is_marked_callback; 762 soft_reference_args.mark_callback_ = mark_object_callback; 763 soft_reference_args.arg_ = arg; 764 // References with a marked referent are removed from the list. 765 soft_reference_queue_.PreserveSomeSoftReferences(&PreserveSoftReferenceCallback, 766 &soft_reference_args); 767 process_mark_stack_callback(arg); 768 } 769} 770 771// Process reference class instances and schedule finalizations. 772void Heap::ProcessReferences(TimingLogger& timings, bool clear_soft, 773 IsMarkedCallback* is_marked_callback, 774 MarkObjectCallback* mark_object_callback, 775 ProcessMarkStackCallback* process_mark_stack_callback, void* arg) { 776 ProcessSoftReferences(timings, clear_soft, is_marked_callback, mark_object_callback, 777 process_mark_stack_callback, arg); 778 timings.StartSplit("(Paused)ProcessReferences"); 779 // Clear all remaining soft and weak references with white referents. 780 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 781 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 782 timings.EndSplit(); 783 // Preserve all white objects with finalize methods and schedule them for finalization. 784 timings.StartSplit("(Paused)EnqueueFinalizerReferences"); 785 finalizer_reference_queue_.EnqueueFinalizerReferences(cleared_references_, is_marked_callback, 786 mark_object_callback, arg); 787 process_mark_stack_callback(arg); 788 timings.EndSplit(); 789 timings.StartSplit("(Paused)ProcessReferences"); 790 // Clear all f-reachable soft and weak references with white referents. 791 soft_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 792 weak_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 793 // Clear all phantom references with white referents. 794 phantom_reference_queue_.ClearWhiteReferences(cleared_references_, is_marked_callback, arg); 795 // At this point all reference queues other than the cleared references should be empty. 796 DCHECK(soft_reference_queue_.IsEmpty()); 797 DCHECK(weak_reference_queue_.IsEmpty()); 798 DCHECK(finalizer_reference_queue_.IsEmpty()); 799 DCHECK(phantom_reference_queue_.IsEmpty()); 800 timings.EndSplit(); 801} 802 803// Process the "referent" field in a java.lang.ref.Reference. If the referent has not yet been 804// marked, put it on the appropriate list in the heap for later processing. 805void Heap::DelayReferenceReferent(mirror::Class* klass, mirror::Reference* ref, 806 IsMarkedCallback is_marked_callback, void* arg) { 807 DCHECK_EQ(klass, ref->GetClass()); 808 mirror::Object* referent = ref->GetReferent(); 809 if (referent != nullptr) { 810 mirror::Object* forward_address = is_marked_callback(referent, arg); 811 // Null means that the object is not currently marked. 812 if (forward_address == nullptr) { 813 Thread* self = Thread::Current(); 814 // TODO: Remove these locks, and use atomic stacks for storing references? 815 // We need to check that the references haven't already been enqueued since we can end up 816 // scanning the same reference multiple times due to dirty cards. 817 if (klass->IsSoftReferenceClass()) { 818 soft_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 819 } else if (klass->IsWeakReferenceClass()) { 820 weak_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 821 } else if (klass->IsFinalizerReferenceClass()) { 822 finalizer_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 823 } else if (klass->IsPhantomReferenceClass()) { 824 phantom_reference_queue_.AtomicEnqueueIfNotEnqueued(self, ref); 825 } else { 826 LOG(FATAL) << "Invalid reference type " << PrettyClass(klass) << " " << std::hex 827 << klass->GetAccessFlags(); 828 } 829 } else if (referent != forward_address) { 830 // Referent is already marked and we need to update it. 831 ref->SetReferent<false>(forward_address); 832 } 833 } 834} 835 836space::ImageSpace* Heap::GetImageSpace() const { 837 for (const auto& space : continuous_spaces_) { 838 if (space->IsImageSpace()) { 839 return space->AsImageSpace(); 840 } 841 } 842 return NULL; 843} 844 845static void MSpaceChunkCallback(void* start, void* end, size_t used_bytes, void* arg) { 846 size_t chunk_size = reinterpret_cast<uint8_t*>(end) - reinterpret_cast<uint8_t*>(start); 847 if (used_bytes < chunk_size) { 848 size_t chunk_free_bytes = chunk_size - used_bytes; 849 size_t& max_contiguous_allocation = *reinterpret_cast<size_t*>(arg); 850 max_contiguous_allocation = std::max(max_contiguous_allocation, chunk_free_bytes); 851 } 852} 853 854void Heap::ThrowOutOfMemoryError(Thread* self, size_t byte_count, bool large_object_allocation) { 855 std::ostringstream oss; 856 size_t total_bytes_free = GetFreeMemory(); 857 oss << "Failed to allocate a " << byte_count << " byte allocation with " << total_bytes_free 858 << " free bytes"; 859 // If the allocation failed due to fragmentation, print out the largest continuous allocation. 860 if (!large_object_allocation && total_bytes_free >= byte_count) { 861 size_t max_contiguous_allocation = 0; 862 for (const auto& space : continuous_spaces_) { 863 if (space->IsMallocSpace()) { 864 // To allow the Walk/InspectAll() to exclusively-lock the mutator 865 // lock, temporarily release the shared access to the mutator 866 // lock here by transitioning to the suspended state. 867 Locks::mutator_lock_->AssertSharedHeld(self); 868 self->TransitionFromRunnableToSuspended(kSuspended); 869 space->AsMallocSpace()->Walk(MSpaceChunkCallback, &max_contiguous_allocation); 870 self->TransitionFromSuspendedToRunnable(); 871 Locks::mutator_lock_->AssertSharedHeld(self); 872 } 873 } 874 oss << "; failed due to fragmentation (largest possible contiguous allocation " 875 << max_contiguous_allocation << " bytes)"; 876 } 877 self->ThrowOutOfMemoryError(oss.str().c_str()); 878} 879 880void Heap::DoPendingTransitionOrTrim() { 881 Thread* self = Thread::Current(); 882 CollectorType desired_collector_type; 883 // Wait until we reach the desired transition time. 884 while (true) { 885 uint64_t wait_time; 886 { 887 MutexLock mu(self, *heap_trim_request_lock_); 888 desired_collector_type = desired_collector_type_; 889 uint64_t current_time = NanoTime(); 890 if (current_time >= heap_transition_target_time_) { 891 break; 892 } 893 wait_time = heap_transition_target_time_ - current_time; 894 } 895 ScopedThreadStateChange tsc(self, kSleeping); 896 usleep(wait_time / 1000); // Usleep takes microseconds. 897 } 898 // Transition the collector if the desired collector type is not the same as the current 899 // collector type. 900 TransitionCollector(desired_collector_type); 901 // Do a heap trim if it is needed. 902 Trim(); 903} 904 905void Heap::Trim() { 906 Thread* self = Thread::Current(); 907 { 908 MutexLock mu(self, *heap_trim_request_lock_); 909 if (!heap_trim_request_pending_ || last_trim_time_ + kHeapTrimWait >= NanoTime()) { 910 return; 911 } 912 last_trim_time_ = NanoTime(); 913 heap_trim_request_pending_ = false; 914 } 915 { 916 // Need to do this before acquiring the locks since we don't want to get suspended while 917 // holding any locks. 918 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 919 // Pretend we are doing a GC to prevent background compaction from deleting the space we are 920 // trimming. 921 MutexLock mu(self, *gc_complete_lock_); 922 // Ensure there is only one GC at a time. 923 WaitForGcToCompleteLocked(self); 924 collector_type_running_ = kCollectorTypeHeapTrim; 925 } 926 uint64_t start_ns = NanoTime(); 927 // Trim the managed spaces. 928 uint64_t total_alloc_space_allocated = 0; 929 uint64_t total_alloc_space_size = 0; 930 uint64_t managed_reclaimed = 0; 931 for (const auto& space : continuous_spaces_) { 932 if (space->IsMallocSpace()) { 933 gc::space::MallocSpace* alloc_space = space->AsMallocSpace(); 934 total_alloc_space_size += alloc_space->Size(); 935 managed_reclaimed += alloc_space->Trim(); 936 } 937 } 938 total_alloc_space_allocated = GetBytesAllocated() - large_object_space_->GetBytesAllocated() - 939 bump_pointer_space_->Size(); 940 const float managed_utilization = static_cast<float>(total_alloc_space_allocated) / 941 static_cast<float>(total_alloc_space_size); 942 uint64_t gc_heap_end_ns = NanoTime(); 943 // We never move things in the native heap, so we can finish the GC at this point. 944 FinishGC(self, collector::kGcTypeNone); 945 // Trim the native heap. 946 dlmalloc_trim(0); 947 size_t native_reclaimed = 0; 948 dlmalloc_inspect_all(DlmallocMadviseCallback, &native_reclaimed); 949 uint64_t end_ns = NanoTime(); 950 VLOG(heap) << "Heap trim of managed (duration=" << PrettyDuration(gc_heap_end_ns - start_ns) 951 << ", advised=" << PrettySize(managed_reclaimed) << ") and native (duration=" 952 << PrettyDuration(end_ns - gc_heap_end_ns) << ", advised=" << PrettySize(native_reclaimed) 953 << ") heaps. Managed heap utilization of " << static_cast<int>(100 * managed_utilization) 954 << "%."; 955} 956 957bool Heap::IsValidObjectAddress(const mirror::Object* obj) const { 958 // Note: we deliberately don't take the lock here, and mustn't test anything that would require 959 // taking the lock. 960 if (obj == nullptr) { 961 return true; 962 } 963 return IsAligned<kObjectAlignment>(obj) && FindSpaceFromObject(obj, true) != nullptr; 964} 965 966bool Heap::IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const { 967 return FindContinuousSpaceFromObject(obj, true) != nullptr; 968} 969 970bool Heap::IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const { 971 if (obj == nullptr || !IsAligned<kObjectAlignment>(obj)) { 972 return false; 973 } 974 for (const auto& space : continuous_spaces_) { 975 if (space->HasAddress(obj)) { 976 return true; 977 } 978 } 979 return false; 980} 981 982bool Heap::IsLiveObjectLocked(mirror::Object* obj, bool search_allocation_stack, 983 bool search_live_stack, bool sorted) { 984 if (UNLIKELY(!IsAligned<kObjectAlignment>(obj))) { 985 return false; 986 } 987 if (bump_pointer_space_ != nullptr && bump_pointer_space_->HasAddress(obj)) { 988 mirror::Class* klass = obj->GetClass<kVerifyNone>(); 989 if (obj == klass) { 990 // This case happens for java.lang.Class. 991 return true; 992 } 993 return VerifyClassClass(klass) && IsLiveObjectLocked(klass); 994 } else if (temp_space_ != nullptr && temp_space_->HasAddress(obj)) { 995 // If we are in the allocated region of the temp space, then we are probably live (e.g. during 996 // a GC). When a GC isn't running End() - Begin() is 0 which means no objects are contained. 997 return temp_space_->Contains(obj); 998 } 999 space::ContinuousSpace* c_space = FindContinuousSpaceFromObject(obj, true); 1000 space::DiscontinuousSpace* d_space = NULL; 1001 if (c_space != nullptr) { 1002 if (c_space->GetLiveBitmap()->Test(obj)) { 1003 return true; 1004 } 1005 } else { 1006 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1007 if (d_space != nullptr) { 1008 if (d_space->GetLiveObjects()->Test(obj)) { 1009 return true; 1010 } 1011 } 1012 } 1013 // This is covering the allocation/live stack swapping that is done without mutators suspended. 1014 for (size_t i = 0; i < (sorted ? 1 : 5); ++i) { 1015 if (i > 0) { 1016 NanoSleep(MsToNs(10)); 1017 } 1018 if (search_allocation_stack) { 1019 if (sorted) { 1020 if (allocation_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1021 return true; 1022 } 1023 } else if (allocation_stack_->Contains(const_cast<mirror::Object*>(obj))) { 1024 return true; 1025 } 1026 } 1027 1028 if (search_live_stack) { 1029 if (sorted) { 1030 if (live_stack_->ContainsSorted(const_cast<mirror::Object*>(obj))) { 1031 return true; 1032 } 1033 } else if (live_stack_->Contains(const_cast<mirror::Object*>(obj))) { 1034 return true; 1035 } 1036 } 1037 } 1038 // We need to check the bitmaps again since there is a race where we mark something as live and 1039 // then clear the stack containing it. 1040 if (c_space != nullptr) { 1041 if (c_space->GetLiveBitmap()->Test(obj)) { 1042 return true; 1043 } 1044 } else { 1045 d_space = FindDiscontinuousSpaceFromObject(obj, true); 1046 if (d_space != nullptr && d_space->GetLiveObjects()->Test(obj)) { 1047 return true; 1048 } 1049 } 1050 return false; 1051} 1052 1053void Heap::DumpSpaces(std::ostream& stream) { 1054 for (const auto& space : continuous_spaces_) { 1055 accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap(); 1056 accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap(); 1057 stream << space << " " << *space << "\n"; 1058 if (live_bitmap != nullptr) { 1059 stream << live_bitmap << " " << *live_bitmap << "\n"; 1060 } 1061 if (mark_bitmap != nullptr) { 1062 stream << mark_bitmap << " " << *mark_bitmap << "\n"; 1063 } 1064 } 1065 for (const auto& space : discontinuous_spaces_) { 1066 stream << space << " " << *space << "\n"; 1067 } 1068} 1069 1070void Heap::VerifyObjectBody(mirror::Object* obj) { 1071 if (this == nullptr && verify_object_mode_ == kVerifyObjectModeDisabled) { 1072 return; 1073 } 1074 // Ignore early dawn of the universe verifications. 1075 if (UNLIKELY(static_cast<size_t>(num_bytes_allocated_.Load()) < 10 * KB)) { 1076 return; 1077 } 1078 CHECK(IsAligned<kObjectAlignment>(obj)) << "Object isn't aligned: " << obj; 1079 mirror::Class* c = obj->GetFieldObject<mirror::Class, kVerifyNone>( 1080 mirror::Object::ClassOffset(), false); 1081 CHECK(c != nullptr) << "Null class in object " << obj; 1082 CHECK(IsAligned<kObjectAlignment>(c)) << "Class " << c << " not aligned in object " << obj; 1083 CHECK(VerifyClassClass(c)); 1084 1085 if (verify_object_mode_ > kVerifyObjectModeFast) { 1086 // Note: the bitmap tests below are racy since we don't hold the heap bitmap lock. 1087 if (!IsLiveObjectLocked(obj)) { 1088 DumpSpaces(); 1089 LOG(FATAL) << "Object is dead: " << obj; 1090 } 1091 } 1092} 1093 1094void Heap::VerificationCallback(mirror::Object* obj, void* arg) { 1095 reinterpret_cast<Heap*>(arg)->VerifyObjectBody(obj); 1096} 1097 1098void Heap::VerifyHeap() { 1099 ReaderMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1100 GetLiveBitmap()->Walk(Heap::VerificationCallback, this); 1101} 1102 1103void Heap::RecordFree(ssize_t freed_objects, ssize_t freed_bytes) { 1104 // Use signed comparison since freed bytes can be negative when background compaction foreground 1105 // transitions occurs. This is caused by the moving objects from a bump pointer space to a 1106 // free list backed space typically increasing memory footprint due to padding and binning. 1107 DCHECK_LE(freed_bytes, static_cast<ssize_t>(num_bytes_allocated_.Load())); 1108 DCHECK_GE(freed_objects, 0); 1109 num_bytes_allocated_.FetchAndSub(freed_bytes); 1110 if (Runtime::Current()->HasStatsEnabled()) { 1111 RuntimeStats* thread_stats = Thread::Current()->GetStats(); 1112 thread_stats->freed_objects += freed_objects; 1113 thread_stats->freed_bytes += freed_bytes; 1114 // TODO: Do this concurrently. 1115 RuntimeStats* global_stats = Runtime::Current()->GetStats(); 1116 global_stats->freed_objects += freed_objects; 1117 global_stats->freed_bytes += freed_bytes; 1118 } 1119} 1120 1121mirror::Object* Heap::AllocateInternalWithGc(Thread* self, AllocatorType allocator, 1122 size_t alloc_size, size_t* bytes_allocated, 1123 size_t* usable_size, 1124 mirror::Class** klass) { 1125 mirror::Object* ptr = nullptr; 1126 bool was_default_allocator = allocator == GetCurrentAllocator(); 1127 DCHECK(klass != nullptr); 1128 SirtRef<mirror::Class> sirt_klass(self, *klass); 1129 // The allocation failed. If the GC is running, block until it completes, and then retry the 1130 // allocation. 1131 collector::GcType last_gc = WaitForGcToComplete(self); 1132 if (last_gc != collector::kGcTypeNone) { 1133 // If we were the default allocator but the allocator changed while we were suspended, 1134 // abort the allocation. 1135 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1136 *klass = sirt_klass.get(); 1137 return nullptr; 1138 } 1139 // A GC was in progress and we blocked, retry allocation now that memory has been freed. 1140 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1141 } 1142 1143 // Loop through our different Gc types and try to Gc until we get enough free memory. 1144 for (collector::GcType gc_type : gc_plan_) { 1145 if (ptr != nullptr) { 1146 break; 1147 } 1148 // Attempt to run the collector, if we succeed, re-try the allocation. 1149 bool gc_ran = 1150 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false) != collector::kGcTypeNone; 1151 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1152 *klass = sirt_klass.get(); 1153 return nullptr; 1154 } 1155 if (gc_ran) { 1156 // Did we free sufficient memory for the allocation to succeed? 1157 ptr = TryToAllocate<true, false>(self, allocator, alloc_size, bytes_allocated, usable_size); 1158 } 1159 } 1160 // Allocations have failed after GCs; this is an exceptional state. 1161 if (ptr == nullptr) { 1162 // Try harder, growing the heap if necessary. 1163 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1164 } 1165 if (ptr == nullptr) { 1166 // Most allocations should have succeeded by now, so the heap is really full, really fragmented, 1167 // or the requested size is really big. Do another GC, collecting SoftReferences this time. The 1168 // VM spec requires that all SoftReferences have been collected and cleared before throwing 1169 // OOME. 1170 VLOG(gc) << "Forcing collection of SoftReferences for " << PrettySize(alloc_size) 1171 << " allocation"; 1172 // TODO: Run finalization, but this may cause more allocations to occur. 1173 // We don't need a WaitForGcToComplete here either. 1174 DCHECK(!gc_plan_.empty()); 1175 CollectGarbageInternal(gc_plan_.back(), kGcCauseForAlloc, true); 1176 if (was_default_allocator && allocator != GetCurrentAllocator()) { 1177 *klass = sirt_klass.get(); 1178 return nullptr; 1179 } 1180 ptr = TryToAllocate<true, true>(self, allocator, alloc_size, bytes_allocated, usable_size); 1181 if (ptr == nullptr) { 1182 ThrowOutOfMemoryError(self, alloc_size, false); 1183 } 1184 } 1185 *klass = sirt_klass.get(); 1186 return ptr; 1187} 1188 1189void Heap::SetTargetHeapUtilization(float target) { 1190 DCHECK_GT(target, 0.0f); // asserted in Java code 1191 DCHECK_LT(target, 1.0f); 1192 target_utilization_ = target; 1193} 1194 1195size_t Heap::GetObjectsAllocated() const { 1196 size_t total = 0; 1197 for (space::AllocSpace* space : alloc_spaces_) { 1198 total += space->GetObjectsAllocated(); 1199 } 1200 return total; 1201} 1202 1203size_t Heap::GetObjectsAllocatedEver() const { 1204 return GetObjectsFreedEver() + GetObjectsAllocated(); 1205} 1206 1207size_t Heap::GetBytesAllocatedEver() const { 1208 return GetBytesFreedEver() + GetBytesAllocated(); 1209} 1210 1211class InstanceCounter { 1212 public: 1213 InstanceCounter(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, uint64_t* counts) 1214 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1215 : classes_(classes), use_is_assignable_from_(use_is_assignable_from), counts_(counts) { 1216 } 1217 static void Callback(mirror::Object* obj, void* arg) 1218 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1219 InstanceCounter* instance_counter = reinterpret_cast<InstanceCounter*>(arg); 1220 mirror::Class* instance_class = obj->GetClass(); 1221 CHECK(instance_class != nullptr); 1222 for (size_t i = 0; i < instance_counter->classes_.size(); ++i) { 1223 if (instance_counter->use_is_assignable_from_) { 1224 if (instance_counter->classes_[i]->IsAssignableFrom(instance_class)) { 1225 ++instance_counter->counts_[i]; 1226 } 1227 } else if (instance_class == instance_counter->classes_[i]) { 1228 ++instance_counter->counts_[i]; 1229 } 1230 } 1231 } 1232 1233 private: 1234 const std::vector<mirror::Class*>& classes_; 1235 bool use_is_assignable_from_; 1236 uint64_t* const counts_; 1237 DISALLOW_COPY_AND_ASSIGN(InstanceCounter); 1238}; 1239 1240void Heap::CountInstances(const std::vector<mirror::Class*>& classes, bool use_is_assignable_from, 1241 uint64_t* counts) { 1242 // Can't do any GC in this function since this may move classes. 1243 Thread* self = Thread::Current(); 1244 auto* old_cause = self->StartAssertNoThreadSuspension("CountInstances"); 1245 InstanceCounter counter(classes, use_is_assignable_from, counts); 1246 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1247 VisitObjects(InstanceCounter::Callback, &counter); 1248 self->EndAssertNoThreadSuspension(old_cause); 1249} 1250 1251class InstanceCollector { 1252 public: 1253 InstanceCollector(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 1254 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1255 : class_(c), max_count_(max_count), instances_(instances) { 1256 } 1257 static void Callback(mirror::Object* obj, void* arg) 1258 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1259 DCHECK(arg != nullptr); 1260 InstanceCollector* instance_collector = reinterpret_cast<InstanceCollector*>(arg); 1261 mirror::Class* instance_class = obj->GetClass(); 1262 if (instance_class == instance_collector->class_) { 1263 if (instance_collector->max_count_ == 0 || 1264 instance_collector->instances_.size() < instance_collector->max_count_) { 1265 instance_collector->instances_.push_back(obj); 1266 } 1267 } 1268 } 1269 1270 private: 1271 mirror::Class* class_; 1272 uint32_t max_count_; 1273 std::vector<mirror::Object*>& instances_; 1274 DISALLOW_COPY_AND_ASSIGN(InstanceCollector); 1275}; 1276 1277void Heap::GetInstances(mirror::Class* c, int32_t max_count, 1278 std::vector<mirror::Object*>& instances) { 1279 // Can't do any GC in this function since this may move classes. 1280 Thread* self = Thread::Current(); 1281 auto* old_cause = self->StartAssertNoThreadSuspension("GetInstances"); 1282 InstanceCollector collector(c, max_count, instances); 1283 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1284 VisitObjects(&InstanceCollector::Callback, &collector); 1285 self->EndAssertNoThreadSuspension(old_cause); 1286} 1287 1288class ReferringObjectsFinder { 1289 public: 1290 ReferringObjectsFinder(mirror::Object* object, int32_t max_count, 1291 std::vector<mirror::Object*>& referring_objects) 1292 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) 1293 : object_(object), max_count_(max_count), referring_objects_(referring_objects) { 1294 } 1295 1296 static void Callback(mirror::Object* obj, void* arg) 1297 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 1298 reinterpret_cast<ReferringObjectsFinder*>(arg)->operator()(obj); 1299 } 1300 1301 // For bitmap Visit. 1302 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 1303 // annotalysis on visitors. 1304 void operator()(const mirror::Object* o) const NO_THREAD_SAFETY_ANALYSIS { 1305 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(o), *this, true); 1306 } 1307 1308 // For MarkSweep::VisitObjectReferences. 1309 void operator()(mirror::Object* referrer, mirror::Object* object, 1310 const MemberOffset&, bool) const { 1311 if (object == object_ && (max_count_ == 0 || referring_objects_.size() < max_count_)) { 1312 referring_objects_.push_back(referrer); 1313 } 1314 } 1315 1316 private: 1317 mirror::Object* object_; 1318 uint32_t max_count_; 1319 std::vector<mirror::Object*>& referring_objects_; 1320 DISALLOW_COPY_AND_ASSIGN(ReferringObjectsFinder); 1321}; 1322 1323void Heap::GetReferringObjects(mirror::Object* o, int32_t max_count, 1324 std::vector<mirror::Object*>& referring_objects) { 1325 // Can't do any GC in this function since this may move the object o. 1326 Thread* self = Thread::Current(); 1327 auto* old_cause = self->StartAssertNoThreadSuspension("GetReferringObjects"); 1328 ReferringObjectsFinder finder(o, max_count, referring_objects); 1329 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 1330 VisitObjects(&ReferringObjectsFinder::Callback, &finder); 1331 self->EndAssertNoThreadSuspension(old_cause); 1332} 1333 1334void Heap::CollectGarbage(bool clear_soft_references) { 1335 // Even if we waited for a GC we still need to do another GC since weaks allocated during the 1336 // last GC will not have necessarily been cleared. 1337 CollectGarbageInternal(gc_plan_.back(), kGcCauseExplicit, clear_soft_references); 1338} 1339 1340void Heap::TransitionCollector(CollectorType collector_type) { 1341 if (collector_type == collector_type_) { 1342 return; 1343 } 1344 VLOG(heap) << "TransitionCollector: " << static_cast<int>(collector_type_) 1345 << " -> " << static_cast<int>(collector_type); 1346 uint64_t start_time = NanoTime(); 1347 uint32_t before_size = GetTotalMemory(); 1348 uint32_t before_allocated = num_bytes_allocated_.Load(); 1349 ThreadList* tl = Runtime::Current()->GetThreadList(); 1350 Thread* self = Thread::Current(); 1351 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1352 Locks::mutator_lock_->AssertNotHeld(self); 1353 const bool copying_transition = 1354 IsCompactingGC(background_collector_type_) || IsCompactingGC(post_zygote_collector_type_); 1355 // Busy wait until we can GC (StartGC can fail if we have a non-zero 1356 // compacting_gc_disable_count_, this should rarely occurs). 1357 for (;;) { 1358 { 1359 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1360 MutexLock mu(self, *gc_complete_lock_); 1361 // Ensure there is only one GC at a time. 1362 WaitForGcToCompleteLocked(self); 1363 // GC can be disabled if someone has a used GetPrimitiveArrayCritical but not yet released. 1364 if (!copying_transition || disable_moving_gc_count_ == 0) { 1365 // TODO: Not hard code in semi-space collector? 1366 collector_type_running_ = copying_transition ? kCollectorTypeSS : collector_type; 1367 break; 1368 } 1369 } 1370 usleep(1000); 1371 } 1372 tl->SuspendAll(); 1373 PreGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1374 switch (collector_type) { 1375 case kCollectorTypeSS: 1376 // Fall-through. 1377 case kCollectorTypeGSS: { 1378 mprotect(temp_space_->Begin(), temp_space_->Capacity(), PROT_READ | PROT_WRITE); 1379 CHECK(main_space_ != nullptr); 1380 Compact(temp_space_, main_space_); 1381 DCHECK(allocator_mem_map_.get() == nullptr); 1382 allocator_mem_map_.reset(main_space_->ReleaseMemMap()); 1383 madvise(main_space_->Begin(), main_space_->Size(), MADV_DONTNEED); 1384 // RemoveSpace does not delete the removed space. 1385 space::Space* old_space = main_space_; 1386 RemoveSpace(old_space); 1387 delete old_space; 1388 break; 1389 } 1390 case kCollectorTypeMS: 1391 // Fall through. 1392 case kCollectorTypeCMS: { 1393 if (IsCompactingGC(collector_type_)) { 1394 // TODO: Use mem-map from temp space? 1395 MemMap* mem_map = allocator_mem_map_.release(); 1396 CHECK(mem_map != nullptr); 1397 size_t starting_size = kDefaultStartingSize; 1398 size_t initial_size = kDefaultInitialSize; 1399 mprotect(mem_map->Begin(), initial_size, PROT_READ | PROT_WRITE); 1400 CHECK(main_space_ == nullptr); 1401 if (kUseRosAlloc) { 1402 main_space_ = 1403 space::RosAllocSpace::CreateFromMemMap(mem_map, "alloc space", starting_size, 1404 initial_size, mem_map->Size(), 1405 mem_map->Size(), low_memory_mode_); 1406 } else { 1407 main_space_ = 1408 space::DlMallocSpace::CreateFromMemMap(mem_map, "alloc space", starting_size, 1409 initial_size, mem_map->Size(), 1410 mem_map->Size()); 1411 } 1412 main_space_->SetFootprintLimit(main_space_->Capacity()); 1413 AddSpace(main_space_); 1414 Compact(main_space_, bump_pointer_space_); 1415 } 1416 break; 1417 } 1418 default: { 1419 LOG(FATAL) << "Attempted to transition to invalid collector type"; 1420 break; 1421 } 1422 } 1423 ChangeCollector(collector_type); 1424 PostGcRosAllocVerification(&semi_space_collector_->GetTimings()); 1425 tl->ResumeAll(); 1426 // Can't call into java code with all threads suspended. 1427 EnqueueClearedReferences(); 1428 uint64_t duration = NanoTime() - start_time; 1429 GrowForUtilization(collector::kGcTypeFull, duration); 1430 FinishGC(self, collector::kGcTypeFull); 1431 int32_t after_size = GetTotalMemory(); 1432 int32_t delta_size = before_size - after_size; 1433 int32_t after_allocated = num_bytes_allocated_.Load(); 1434 int32_t delta_allocated = before_allocated - after_allocated; 1435 const std::string saved_bytes_str = 1436 delta_size < 0 ? "-" + PrettySize(-delta_size) : PrettySize(delta_size); 1437 LOG(INFO) << "Heap transition to " << process_state_ << " took " 1438 << PrettyDuration(duration) << " " << PrettySize(before_size) << "->" 1439 << PrettySize(after_size) << " from " << PrettySize(delta_allocated) << " to " 1440 << PrettySize(delta_size) << " saved"; 1441} 1442 1443void Heap::ChangeCollector(CollectorType collector_type) { 1444 // TODO: Only do this with all mutators suspended to avoid races. 1445 if (collector_type != collector_type_) { 1446 collector_type_ = collector_type; 1447 gc_plan_.clear(); 1448 switch (collector_type_) { 1449 case kCollectorTypeSS: // Fall-through. 1450 case kCollectorTypeGSS: { 1451 gc_plan_.push_back(collector::kGcTypeFull); 1452 if (use_tlab_) { 1453 ChangeAllocator(kAllocatorTypeTLAB); 1454 } else { 1455 ChangeAllocator(kAllocatorTypeBumpPointer); 1456 } 1457 break; 1458 } 1459 case kCollectorTypeMS: { 1460 gc_plan_.push_back(collector::kGcTypeSticky); 1461 gc_plan_.push_back(collector::kGcTypePartial); 1462 gc_plan_.push_back(collector::kGcTypeFull); 1463 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1464 break; 1465 } 1466 case kCollectorTypeCMS: { 1467 gc_plan_.push_back(collector::kGcTypeSticky); 1468 gc_plan_.push_back(collector::kGcTypePartial); 1469 gc_plan_.push_back(collector::kGcTypeFull); 1470 ChangeAllocator(kUseRosAlloc ? kAllocatorTypeRosAlloc : kAllocatorTypeDlMalloc); 1471 break; 1472 } 1473 default: { 1474 LOG(FATAL) << "Unimplemented"; 1475 } 1476 } 1477 if (IsGcConcurrent()) { 1478 concurrent_start_bytes_ = 1479 std::max(max_allowed_footprint_, kMinConcurrentRemainingBytes) - kMinConcurrentRemainingBytes; 1480 } else { 1481 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 1482 } 1483 } 1484} 1485 1486// Special compacting collector which uses sub-optimal bin packing to reduce zygote space size. 1487class ZygoteCompactingCollector FINAL : public collector::SemiSpace { 1488 public: 1489 explicit ZygoteCompactingCollector(gc::Heap* heap) : SemiSpace(heap, false, "zygote collector"), 1490 bin_live_bitmap_(nullptr), bin_mark_bitmap_(nullptr) { 1491 } 1492 1493 void BuildBins(space::ContinuousSpace* space) { 1494 bin_live_bitmap_ = space->GetLiveBitmap(); 1495 bin_mark_bitmap_ = space->GetMarkBitmap(); 1496 BinContext context; 1497 context.prev_ = reinterpret_cast<uintptr_t>(space->Begin()); 1498 context.collector_ = this; 1499 WriterMutexLock mu(Thread::Current(), *Locks::heap_bitmap_lock_); 1500 // Note: This requires traversing the space in increasing order of object addresses. 1501 bin_live_bitmap_->Walk(Callback, reinterpret_cast<void*>(&context)); 1502 // Add the last bin which spans after the last object to the end of the space. 1503 AddBin(reinterpret_cast<uintptr_t>(space->End()) - context.prev_, context.prev_); 1504 } 1505 1506 private: 1507 struct BinContext { 1508 uintptr_t prev_; // The end of the previous object. 1509 ZygoteCompactingCollector* collector_; 1510 }; 1511 // Maps from bin sizes to locations. 1512 std::multimap<size_t, uintptr_t> bins_; 1513 // Live bitmap of the space which contains the bins. 1514 accounting::SpaceBitmap* bin_live_bitmap_; 1515 // Mark bitmap of the space which contains the bins. 1516 accounting::SpaceBitmap* bin_mark_bitmap_; 1517 1518 static void Callback(mirror::Object* obj, void* arg) 1519 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) { 1520 DCHECK(arg != nullptr); 1521 BinContext* context = reinterpret_cast<BinContext*>(arg); 1522 ZygoteCompactingCollector* collector = context->collector_; 1523 uintptr_t object_addr = reinterpret_cast<uintptr_t>(obj); 1524 size_t bin_size = object_addr - context->prev_; 1525 // Add the bin consisting of the end of the previous object to the start of the current object. 1526 collector->AddBin(bin_size, context->prev_); 1527 context->prev_ = object_addr + RoundUp(obj->SizeOf(), kObjectAlignment); 1528 } 1529 1530 void AddBin(size_t size, uintptr_t position) { 1531 if (size != 0) { 1532 bins_.insert(std::make_pair(size, position)); 1533 } 1534 } 1535 1536 virtual bool ShouldSweepSpace(space::ContinuousSpace* space) const { 1537 // Don't sweep any spaces since we probably blasted the internal accounting of the free list 1538 // allocator. 1539 return false; 1540 } 1541 1542 virtual mirror::Object* MarkNonForwardedObject(mirror::Object* obj) 1543 EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_, Locks::mutator_lock_) { 1544 size_t object_size = RoundUp(obj->SizeOf(), kObjectAlignment); 1545 mirror::Object* forward_address; 1546 // Find the smallest bin which we can move obj in. 1547 auto it = bins_.lower_bound(object_size); 1548 if (it == bins_.end()) { 1549 // No available space in the bins, place it in the target space instead (grows the zygote 1550 // space). 1551 size_t bytes_allocated; 1552 forward_address = to_space_->Alloc(self_, object_size, &bytes_allocated, nullptr); 1553 if (to_space_live_bitmap_ != nullptr) { 1554 to_space_live_bitmap_->Set(forward_address); 1555 } else { 1556 GetHeap()->GetNonMovingSpace()->GetLiveBitmap()->Set(forward_address); 1557 GetHeap()->GetNonMovingSpace()->GetMarkBitmap()->Set(forward_address); 1558 } 1559 } else { 1560 size_t size = it->first; 1561 uintptr_t pos = it->second; 1562 bins_.erase(it); // Erase the old bin which we replace with the new smaller bin. 1563 forward_address = reinterpret_cast<mirror::Object*>(pos); 1564 // Set the live and mark bits so that sweeping system weaks works properly. 1565 bin_live_bitmap_->Set(forward_address); 1566 bin_mark_bitmap_->Set(forward_address); 1567 DCHECK_GE(size, object_size); 1568 AddBin(size - object_size, pos + object_size); // Add a new bin with the remaining space. 1569 } 1570 // Copy the object over to its new location. 1571 memcpy(reinterpret_cast<void*>(forward_address), obj, object_size); 1572 if (kUseBrooksPointer) { 1573 obj->AssertSelfBrooksPointer(); 1574 DCHECK_EQ(forward_address->GetBrooksPointer(), obj); 1575 forward_address->SetBrooksPointer(forward_address); 1576 forward_address->AssertSelfBrooksPointer(); 1577 } 1578 return forward_address; 1579 } 1580}; 1581 1582void Heap::UnBindBitmaps() { 1583 for (const auto& space : GetContinuousSpaces()) { 1584 if (space->IsContinuousMemMapAllocSpace()) { 1585 space::ContinuousMemMapAllocSpace* alloc_space = space->AsContinuousMemMapAllocSpace(); 1586 if (alloc_space->HasBoundBitmaps()) { 1587 alloc_space->UnBindBitmaps(); 1588 } 1589 } 1590 } 1591} 1592 1593void Heap::PreZygoteFork() { 1594 CollectGarbageInternal(collector::kGcTypeFull, kGcCauseBackground, false); 1595 static Mutex zygote_creation_lock_("zygote creation lock", kZygoteCreationLock); 1596 Thread* self = Thread::Current(); 1597 MutexLock mu(self, zygote_creation_lock_); 1598 // Try to see if we have any Zygote spaces. 1599 if (have_zygote_space_) { 1600 return; 1601 } 1602 VLOG(heap) << "Starting PreZygoteFork"; 1603 // Trim the pages at the end of the non moving space. 1604 non_moving_space_->Trim(); 1605 non_moving_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1606 // Change the collector to the post zygote one. 1607 ChangeCollector(post_zygote_collector_type_); 1608 // TODO: Delete bump_pointer_space_ and temp_pointer_space_? 1609 if (semi_space_collector_ != nullptr) { 1610 // Temporarily disable rosalloc verification because the zygote 1611 // compaction will mess up the rosalloc internal metadata. 1612 ScopedDisableRosAllocVerification disable_rosalloc_verif(this); 1613 ZygoteCompactingCollector zygote_collector(this); 1614 zygote_collector.BuildBins(non_moving_space_); 1615 // Create a new bump pointer space which we will compact into. 1616 space::BumpPointerSpace target_space("zygote bump space", non_moving_space_->End(), 1617 non_moving_space_->Limit()); 1618 // Compact the bump pointer space to a new zygote bump pointer space. 1619 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1620 zygote_collector.SetFromSpace(bump_pointer_space_); 1621 zygote_collector.SetToSpace(&target_space); 1622 zygote_collector.Run(kGcCauseCollectorTransition, false); 1623 CHECK(temp_space_->IsEmpty()); 1624 total_objects_freed_ever_ += semi_space_collector_->GetFreedObjects(); 1625 total_bytes_freed_ever_ += semi_space_collector_->GetFreedBytes(); 1626 // Update the end and write out image. 1627 non_moving_space_->SetEnd(target_space.End()); 1628 non_moving_space_->SetLimit(target_space.Limit()); 1629 VLOG(heap) << "Zygote size " << non_moving_space_->Size() << " bytes"; 1630 } 1631 // Save the old space so that we can remove it after we complete creating the zygote space. 1632 space::MallocSpace* old_alloc_space = non_moving_space_; 1633 // Turn the current alloc space into a zygote space and obtain the new alloc space composed of 1634 // the remaining available space. 1635 // Remove the old space before creating the zygote space since creating the zygote space sets 1636 // the old alloc space's bitmaps to nullptr. 1637 RemoveSpace(old_alloc_space); 1638 if (collector::SemiSpace::kUseRememberedSet) { 1639 // Sanity bound check. 1640 FindRememberedSetFromSpace(old_alloc_space)->AssertAllDirtyCardsAreWithinSpace(); 1641 // Remove the remembered set for the now zygote space (the old 1642 // non-moving space). Note now that we have compacted objects into 1643 // the zygote space, the data in the remembered set is no longer 1644 // needed. The zygote space will instead have a mod-union table 1645 // from this point on. 1646 RemoveRememberedSet(old_alloc_space); 1647 } 1648 space::ZygoteSpace* zygote_space = old_alloc_space->CreateZygoteSpace("alloc space", 1649 low_memory_mode_, 1650 &main_space_); 1651 delete old_alloc_space; 1652 CHECK(zygote_space != nullptr) << "Failed creating zygote space"; 1653 AddSpace(zygote_space, false); 1654 CHECK(main_space_ != nullptr); 1655 if (main_space_->IsRosAllocSpace()) { 1656 rosalloc_space_ = main_space_->AsRosAllocSpace(); 1657 } else if (main_space_->IsDlMallocSpace()) { 1658 dlmalloc_space_ = main_space_->AsDlMallocSpace(); 1659 } 1660 main_space_->SetFootprintLimit(main_space_->Capacity()); 1661 AddSpace(main_space_); 1662 have_zygote_space_ = true; 1663 // Enable large object space allocations. 1664 large_object_threshold_ = kDefaultLargeObjectThreshold; 1665 // Create the zygote space mod union table. 1666 accounting::ModUnionTable* mod_union_table = 1667 new accounting::ModUnionTableCardCache("zygote space mod-union table", this, zygote_space); 1668 CHECK(mod_union_table != nullptr) << "Failed to create zygote space mod-union table"; 1669 AddModUnionTable(mod_union_table); 1670 if (collector::SemiSpace::kUseRememberedSet) { 1671 // Add a new remembered set for the new main space. 1672 accounting::RememberedSet* main_space_rem_set = 1673 new accounting::RememberedSet("Main space remembered set", this, main_space_); 1674 CHECK(main_space_rem_set != nullptr) << "Failed to create main space remembered set"; 1675 AddRememberedSet(main_space_rem_set); 1676 } 1677 // Can't use RosAlloc for non moving space due to thread local buffers. 1678 // TODO: Non limited space for non-movable objects? 1679 MemMap* mem_map = post_zygote_non_moving_space_mem_map_.release(); 1680 space::MallocSpace* new_non_moving_space = 1681 space::DlMallocSpace::CreateFromMemMap(mem_map, "Non moving dlmalloc space", kPageSize, 1682 2 * MB, mem_map->Size(), mem_map->Size()); 1683 AddSpace(new_non_moving_space, false); 1684 CHECK(new_non_moving_space != nullptr) << "Failed to create new non-moving space"; 1685 new_non_moving_space->SetFootprintLimit(new_non_moving_space->Capacity()); 1686 non_moving_space_ = new_non_moving_space; 1687 if (collector::SemiSpace::kUseRememberedSet) { 1688 // Add a new remembered set for the post-zygote non-moving space. 1689 accounting::RememberedSet* post_zygote_non_moving_space_rem_set = 1690 new accounting::RememberedSet("Post-zygote non-moving space remembered set", this, 1691 non_moving_space_); 1692 CHECK(post_zygote_non_moving_space_rem_set != nullptr) 1693 << "Failed to create post-zygote non-moving space remembered set"; 1694 AddRememberedSet(post_zygote_non_moving_space_rem_set); 1695 } 1696} 1697 1698void Heap::FlushAllocStack() { 1699 MarkAllocStackAsLive(allocation_stack_.get()); 1700 allocation_stack_->Reset(); 1701} 1702 1703void Heap::MarkAllocStack(accounting::SpaceBitmap* bitmap1, 1704 accounting::SpaceBitmap* bitmap2, 1705 accounting::ObjectSet* large_objects, 1706 accounting::ObjectStack* stack) { 1707 DCHECK(bitmap1 != nullptr); 1708 DCHECK(bitmap2 != nullptr); 1709 mirror::Object** limit = stack->End(); 1710 for (mirror::Object** it = stack->Begin(); it != limit; ++it) { 1711 const mirror::Object* obj = *it; 1712 if (!kUseThreadLocalAllocationStack || obj != nullptr) { 1713 if (bitmap1->HasAddress(obj)) { 1714 bitmap1->Set(obj); 1715 } else if (bitmap2->HasAddress(obj)) { 1716 bitmap2->Set(obj); 1717 } else { 1718 large_objects->Set(obj); 1719 } 1720 } 1721 } 1722} 1723 1724void Heap::SwapSemiSpaces() { 1725 // Swap the spaces so we allocate into the space which we just evacuated. 1726 std::swap(bump_pointer_space_, temp_space_); 1727 bump_pointer_space_->Clear(); 1728} 1729 1730void Heap::Compact(space::ContinuousMemMapAllocSpace* target_space, 1731 space::ContinuousMemMapAllocSpace* source_space) { 1732 CHECK(kMovingCollector); 1733 CHECK_NE(target_space, source_space) << "In-place compaction currently unsupported"; 1734 if (target_space != source_space) { 1735 semi_space_collector_->SetFromSpace(source_space); 1736 semi_space_collector_->SetToSpace(target_space); 1737 semi_space_collector_->Run(kGcCauseCollectorTransition, false); 1738 } 1739} 1740 1741collector::GcType Heap::CollectGarbageInternal(collector::GcType gc_type, GcCause gc_cause, 1742 bool clear_soft_references) { 1743 Thread* self = Thread::Current(); 1744 Runtime* runtime = Runtime::Current(); 1745 // If the heap can't run the GC, silently fail and return that no GC was run. 1746 switch (gc_type) { 1747 case collector::kGcTypePartial: { 1748 if (!have_zygote_space_) { 1749 return collector::kGcTypeNone; 1750 } 1751 break; 1752 } 1753 default: { 1754 // Other GC types don't have any special cases which makes them not runnable. The main case 1755 // here is full GC. 1756 } 1757 } 1758 ScopedThreadStateChange tsc(self, kWaitingPerformingGc); 1759 Locks::mutator_lock_->AssertNotHeld(self); 1760 if (self->IsHandlingStackOverflow()) { 1761 LOG(WARNING) << "Performing GC on a thread that is handling a stack overflow."; 1762 } 1763 bool compacting_gc; 1764 { 1765 gc_complete_lock_->AssertNotHeld(self); 1766 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 1767 MutexLock mu(self, *gc_complete_lock_); 1768 // Ensure there is only one GC at a time. 1769 WaitForGcToCompleteLocked(self); 1770 compacting_gc = IsCompactingGC(collector_type_); 1771 // GC can be disabled if someone has a used GetPrimitiveArrayCritical. 1772 if (compacting_gc && disable_moving_gc_count_ != 0) { 1773 LOG(WARNING) << "Skipping GC due to disable moving GC count " << disable_moving_gc_count_; 1774 return collector::kGcTypeNone; 1775 } 1776 collector_type_running_ = collector_type_; 1777 } 1778 1779 if (gc_cause == kGcCauseForAlloc && runtime->HasStatsEnabled()) { 1780 ++runtime->GetStats()->gc_for_alloc_count; 1781 ++self->GetStats()->gc_for_alloc_count; 1782 } 1783 uint64_t gc_start_time_ns = NanoTime(); 1784 uint64_t gc_start_size = GetBytesAllocated(); 1785 // Approximate allocation rate in bytes / second. 1786 uint64_t ms_delta = NsToMs(gc_start_time_ns - last_gc_time_ns_); 1787 // Back to back GCs can cause 0 ms of wait time in between GC invocations. 1788 if (LIKELY(ms_delta != 0)) { 1789 allocation_rate_ = ((gc_start_size - last_gc_size_) * 1000) / ms_delta; 1790 VLOG(heap) << "Allocation rate: " << PrettySize(allocation_rate_) << "/s"; 1791 } 1792 1793 DCHECK_LT(gc_type, collector::kGcTypeMax); 1794 DCHECK_NE(gc_type, collector::kGcTypeNone); 1795 1796 collector::GarbageCollector* collector = nullptr; 1797 // TODO: Clean this up. 1798 if (compacting_gc) { 1799 DCHECK(current_allocator_ == kAllocatorTypeBumpPointer || 1800 current_allocator_ == kAllocatorTypeTLAB); 1801 gc_type = semi_space_collector_->GetGcType(); 1802 CHECK(temp_space_->IsEmpty()); 1803 semi_space_collector_->SetFromSpace(bump_pointer_space_); 1804 semi_space_collector_->SetToSpace(temp_space_); 1805 temp_space_->GetMemMap()->Protect(PROT_READ | PROT_WRITE); 1806 collector = semi_space_collector_; 1807 gc_type = collector::kGcTypeFull; 1808 } else if (current_allocator_ == kAllocatorTypeRosAlloc || 1809 current_allocator_ == kAllocatorTypeDlMalloc) { 1810 for (const auto& cur_collector : garbage_collectors_) { 1811 if (cur_collector->GetCollectorType() == collector_type_ && 1812 cur_collector->GetGcType() == gc_type) { 1813 collector = cur_collector; 1814 break; 1815 } 1816 } 1817 } else { 1818 LOG(FATAL) << "Invalid current allocator " << current_allocator_; 1819 } 1820 CHECK(collector != nullptr) 1821 << "Could not find garbage collector with collector_type=" 1822 << static_cast<size_t>(collector_type_) << " and gc_type=" << gc_type; 1823 ATRACE_BEGIN(StringPrintf("%s %s GC", PrettyCause(gc_cause), collector->GetName()).c_str()); 1824 if (!clear_soft_references) { 1825 clear_soft_references = gc_type != collector::kGcTypeSticky; // TODO: GSS? 1826 } 1827 collector->Run(gc_cause, clear_soft_references || Runtime::Current()->IsZygote()); 1828 total_objects_freed_ever_ += collector->GetFreedObjects(); 1829 total_bytes_freed_ever_ += collector->GetFreedBytes(); 1830 RequestHeapTrim(); 1831 // Enqueue cleared references. 1832 EnqueueClearedReferences(); 1833 // Grow the heap so that we know when to perform the next GC. 1834 GrowForUtilization(gc_type, collector->GetDurationNs()); 1835 if (CareAboutPauseTimes()) { 1836 const size_t duration = collector->GetDurationNs(); 1837 std::vector<uint64_t> pauses = collector->GetPauseTimes(); 1838 // GC for alloc pauses the allocating thread, so consider it as a pause. 1839 bool was_slow = duration > long_gc_log_threshold_ || 1840 (gc_cause == kGcCauseForAlloc && duration > long_pause_log_threshold_); 1841 if (!was_slow) { 1842 for (uint64_t pause : pauses) { 1843 was_slow = was_slow || pause > long_pause_log_threshold_; 1844 } 1845 } 1846 if (was_slow) { 1847 const size_t percent_free = GetPercentFree(); 1848 const size_t current_heap_size = GetBytesAllocated(); 1849 const size_t total_memory = GetTotalMemory(); 1850 std::ostringstream pause_string; 1851 for (size_t i = 0; i < pauses.size(); ++i) { 1852 pause_string << PrettyDuration((pauses[i] / 1000) * 1000) 1853 << ((i != pauses.size() - 1) ? ", " : ""); 1854 } 1855 LOG(INFO) << gc_cause << " " << collector->GetName() 1856 << " GC freed " << collector->GetFreedObjects() << "(" 1857 << PrettySize(collector->GetFreedBytes()) << ") AllocSpace objects, " 1858 << collector->GetFreedLargeObjects() << "(" 1859 << PrettySize(collector->GetFreedLargeObjectBytes()) << ") LOS objects, " 1860 << percent_free << "% free, " << PrettySize(current_heap_size) << "/" 1861 << PrettySize(total_memory) << ", " << "paused " << pause_string.str() 1862 << " total " << PrettyDuration((duration / 1000) * 1000); 1863 if (VLOG_IS_ON(heap)) { 1864 LOG(INFO) << Dumpable<TimingLogger>(collector->GetTimings()); 1865 } 1866 } 1867 } 1868 FinishGC(self, gc_type); 1869 ATRACE_END(); 1870 1871 // Inform DDMS that a GC completed. 1872 Dbg::GcDidFinish(); 1873 return gc_type; 1874} 1875 1876void Heap::FinishGC(Thread* self, collector::GcType gc_type) { 1877 MutexLock mu(self, *gc_complete_lock_); 1878 collector_type_running_ = kCollectorTypeNone; 1879 if (gc_type != collector::kGcTypeNone) { 1880 last_gc_type_ = gc_type; 1881 } 1882 // Wake anyone who may have been waiting for the GC to complete. 1883 gc_complete_cond_->Broadcast(self); 1884} 1885 1886static void RootMatchesObjectVisitor(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 1887 RootType /*root_type*/) { 1888 mirror::Object* obj = reinterpret_cast<mirror::Object*>(arg); 1889 if (*root == obj) { 1890 LOG(INFO) << "Object " << obj << " is a root"; 1891 } 1892} 1893 1894class ScanVisitor { 1895 public: 1896 void operator()(const mirror::Object* obj) const { 1897 LOG(ERROR) << "Would have rescanned object " << obj; 1898 } 1899}; 1900 1901// Verify a reference from an object. 1902class VerifyReferenceVisitor { 1903 public: 1904 explicit VerifyReferenceVisitor(Heap* heap) 1905 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) 1906 : heap_(heap), failed_(false) {} 1907 1908 bool Failed() const { 1909 return failed_; 1910 } 1911 1912 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for smarter 1913 // analysis on visitors. 1914 void operator()(mirror::Object* obj, mirror::Object* ref, 1915 const MemberOffset& offset, bool /* is_static */) const 1916 NO_THREAD_SAFETY_ANALYSIS { 1917 if (ref == nullptr || IsLive(ref)) { 1918 // Verify that the reference is live. 1919 return; 1920 } 1921 if (!failed_) { 1922 // Print message on only on first failure to prevent spam. 1923 LOG(ERROR) << "!!!!!!!!!!!!!!Heap corruption detected!!!!!!!!!!!!!!!!!!!"; 1924 failed_ = true; 1925 } 1926 if (obj != nullptr) { 1927 accounting::CardTable* card_table = heap_->GetCardTable(); 1928 accounting::ObjectStack* alloc_stack = heap_->allocation_stack_.get(); 1929 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 1930 byte* card_addr = card_table->CardFromAddr(obj); 1931 LOG(ERROR) << "Object " << obj << " references dead object " << ref << " at offset " 1932 << offset << "\n card value = " << static_cast<int>(*card_addr); 1933 if (heap_->IsValidObjectAddress(obj->GetClass())) { 1934 LOG(ERROR) << "Obj type " << PrettyTypeOf(obj); 1935 } else { 1936 LOG(ERROR) << "Object " << obj << " class(" << obj->GetClass() << ") not a heap address"; 1937 } 1938 1939 // Attmept to find the class inside of the recently freed objects. 1940 space::ContinuousSpace* ref_space = heap_->FindContinuousSpaceFromObject(ref, true); 1941 if (ref_space != nullptr && ref_space->IsMallocSpace()) { 1942 space::MallocSpace* space = ref_space->AsMallocSpace(); 1943 mirror::Class* ref_class = space->FindRecentFreedObject(ref); 1944 if (ref_class != nullptr) { 1945 LOG(ERROR) << "Reference " << ref << " found as a recently freed object with class " 1946 << PrettyClass(ref_class); 1947 } else { 1948 LOG(ERROR) << "Reference " << ref << " not found as a recently freed object"; 1949 } 1950 } 1951 1952 if (ref->GetClass() != nullptr && heap_->IsValidObjectAddress(ref->GetClass()) && 1953 ref->GetClass()->IsClass()) { 1954 LOG(ERROR) << "Ref type " << PrettyTypeOf(ref); 1955 } else { 1956 LOG(ERROR) << "Ref " << ref << " class(" << ref->GetClass() 1957 << ") is not a valid heap address"; 1958 } 1959 1960 card_table->CheckAddrIsInCardTable(reinterpret_cast<const byte*>(obj)); 1961 void* cover_begin = card_table->AddrFromCard(card_addr); 1962 void* cover_end = reinterpret_cast<void*>(reinterpret_cast<size_t>(cover_begin) + 1963 accounting::CardTable::kCardSize); 1964 LOG(ERROR) << "Card " << reinterpret_cast<void*>(card_addr) << " covers " << cover_begin 1965 << "-" << cover_end; 1966 accounting::SpaceBitmap* bitmap = heap_->GetLiveBitmap()->GetContinuousSpaceBitmap(obj); 1967 1968 if (bitmap == nullptr) { 1969 LOG(ERROR) << "Object " << obj << " has no bitmap"; 1970 if (!VerifyClassClass(obj->GetClass())) { 1971 LOG(ERROR) << "Object " << obj << " failed class verification!"; 1972 } 1973 } else { 1974 // Print out how the object is live. 1975 if (bitmap->Test(obj)) { 1976 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 1977 } 1978 if (alloc_stack->Contains(const_cast<mirror::Object*>(obj))) { 1979 LOG(ERROR) << "Object " << obj << " found in allocation stack"; 1980 } 1981 if (live_stack->Contains(const_cast<mirror::Object*>(obj))) { 1982 LOG(ERROR) << "Object " << obj << " found in live stack"; 1983 } 1984 if (alloc_stack->Contains(const_cast<mirror::Object*>(ref))) { 1985 LOG(ERROR) << "Ref " << ref << " found in allocation stack"; 1986 } 1987 if (live_stack->Contains(const_cast<mirror::Object*>(ref))) { 1988 LOG(ERROR) << "Ref " << ref << " found in live stack"; 1989 } 1990 // Attempt to see if the card table missed the reference. 1991 ScanVisitor scan_visitor; 1992 byte* byte_cover_begin = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr)); 1993 card_table->Scan(bitmap, byte_cover_begin, 1994 byte_cover_begin + accounting::CardTable::kCardSize, scan_visitor); 1995 } 1996 1997 // Search to see if any of the roots reference our object. 1998 void* arg = const_cast<void*>(reinterpret_cast<const void*>(obj)); 1999 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2000 2001 // Search to see if any of the roots reference our reference. 2002 arg = const_cast<void*>(reinterpret_cast<const void*>(ref)); 2003 Runtime::Current()->VisitRoots(&RootMatchesObjectVisitor, arg); 2004 } else { 2005 LOG(ERROR) << "Root " << ref << " is dead with type " << PrettyTypeOf(ref); 2006 } 2007 } 2008 2009 bool IsLive(mirror::Object* obj) const NO_THREAD_SAFETY_ANALYSIS { 2010 return heap_->IsLiveObjectLocked(obj, true, false, true); 2011 } 2012 2013 static void VerifyRoots(mirror::Object** root, void* arg, uint32_t /*thread_id*/, 2014 RootType /*root_type*/) { 2015 VerifyReferenceVisitor* visitor = reinterpret_cast<VerifyReferenceVisitor*>(arg); 2016 (*visitor)(nullptr, *root, MemberOffset(0), true); 2017 } 2018 2019 private: 2020 Heap* const heap_; 2021 mutable bool failed_; 2022}; 2023 2024// Verify all references within an object, for use with HeapBitmap::Visit. 2025class VerifyObjectVisitor { 2026 public: 2027 explicit VerifyObjectVisitor(Heap* heap) : heap_(heap), failed_(false) {} 2028 2029 void operator()(mirror::Object* obj) const 2030 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2031 // Note: we are verifying the references in obj but not obj itself, this is because obj must 2032 // be live or else how did we find it in the live bitmap? 2033 VerifyReferenceVisitor visitor(heap_); 2034 // The class doesn't count as a reference but we should verify it anyways. 2035 collector::MarkSweep::VisitObjectReferences(obj, visitor, true); 2036 if (obj->IsReferenceInstance()) { 2037 mirror::Reference* ref = obj->AsReference(); 2038 visitor(obj, ref->GetReferent(), mirror::Reference::ReferentOffset(), false); 2039 } 2040 failed_ = failed_ || visitor.Failed(); 2041 } 2042 2043 static void VisitCallback(mirror::Object* obj, void* arg) 2044 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2045 VerifyObjectVisitor* visitor = reinterpret_cast<VerifyObjectVisitor*>(arg); 2046 visitor->operator()(obj); 2047 } 2048 2049 bool Failed() const { 2050 return failed_; 2051 } 2052 2053 private: 2054 Heap* const heap_; 2055 mutable bool failed_; 2056}; 2057 2058// Must do this with mutators suspended since we are directly accessing the allocation stacks. 2059bool Heap::VerifyHeapReferences() { 2060 Thread* self = Thread::Current(); 2061 Locks::mutator_lock_->AssertExclusiveHeld(self); 2062 // Lets sort our allocation stacks so that we can efficiently binary search them. 2063 allocation_stack_->Sort(); 2064 live_stack_->Sort(); 2065 // Since we sorted the allocation stack content, need to revoke all 2066 // thread-local allocation stacks. 2067 RevokeAllThreadLocalAllocationStacks(self); 2068 VerifyObjectVisitor visitor(this); 2069 // Verify objects in the allocation stack since these will be objects which were: 2070 // 1. Allocated prior to the GC (pre GC verification). 2071 // 2. Allocated during the GC (pre sweep GC verification). 2072 // We don't want to verify the objects in the live stack since they themselves may be 2073 // pointing to dead objects if they are not reachable. 2074 VisitObjects(VerifyObjectVisitor::VisitCallback, &visitor); 2075 // Verify the roots: 2076 Runtime::Current()->VisitRoots(VerifyReferenceVisitor::VerifyRoots, &visitor); 2077 if (visitor.Failed()) { 2078 // Dump mod-union tables. 2079 for (const auto& table_pair : mod_union_tables_) { 2080 accounting::ModUnionTable* mod_union_table = table_pair.second; 2081 mod_union_table->Dump(LOG(ERROR) << mod_union_table->GetName() << ": "); 2082 } 2083 // Dump remembered sets. 2084 for (const auto& table_pair : remembered_sets_) { 2085 accounting::RememberedSet* remembered_set = table_pair.second; 2086 remembered_set->Dump(LOG(ERROR) << remembered_set->GetName() << ": "); 2087 } 2088 DumpSpaces(); 2089 return false; 2090 } 2091 return true; 2092} 2093 2094class VerifyReferenceCardVisitor { 2095 public: 2096 VerifyReferenceCardVisitor(Heap* heap, bool* failed) 2097 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, 2098 Locks::heap_bitmap_lock_) 2099 : heap_(heap), failed_(failed) { 2100 } 2101 2102 // TODO: Fix lock analysis to not use NO_THREAD_SAFETY_ANALYSIS, requires support for 2103 // annotalysis on visitors. 2104 void operator()(mirror::Object* obj, mirror::Object* ref, const MemberOffset& offset, 2105 bool is_static) const NO_THREAD_SAFETY_ANALYSIS { 2106 // Filter out class references since changing an object's class does not mark the card as dirty. 2107 // Also handles large objects, since the only reference they hold is a class reference. 2108 if (ref != NULL && !ref->IsClass()) { 2109 accounting::CardTable* card_table = heap_->GetCardTable(); 2110 // If the object is not dirty and it is referencing something in the live stack other than 2111 // class, then it must be on a dirty card. 2112 if (!card_table->AddrIsInCardTable(obj)) { 2113 LOG(ERROR) << "Object " << obj << " is not in the address range of the card table"; 2114 *failed_ = true; 2115 } else if (!card_table->IsDirty(obj)) { 2116 // TODO: Check mod-union tables. 2117 // Card should be either kCardDirty if it got re-dirtied after we aged it, or 2118 // kCardDirty - 1 if it didnt get touched since we aged it. 2119 accounting::ObjectStack* live_stack = heap_->live_stack_.get(); 2120 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(ref))) { 2121 if (live_stack->ContainsSorted(const_cast<mirror::Object*>(obj))) { 2122 LOG(ERROR) << "Object " << obj << " found in live stack"; 2123 } 2124 if (heap_->GetLiveBitmap()->Test(obj)) { 2125 LOG(ERROR) << "Object " << obj << " found in live bitmap"; 2126 } 2127 LOG(ERROR) << "Object " << obj << " " << PrettyTypeOf(obj) 2128 << " references " << ref << " " << PrettyTypeOf(ref) << " in live stack"; 2129 2130 // Print which field of the object is dead. 2131 if (!obj->IsObjectArray()) { 2132 mirror::Class* klass = is_static ? obj->AsClass() : obj->GetClass(); 2133 CHECK(klass != NULL); 2134 mirror::ObjectArray<mirror::ArtField>* fields = is_static ? klass->GetSFields() 2135 : klass->GetIFields(); 2136 CHECK(fields != NULL); 2137 for (int32_t i = 0; i < fields->GetLength(); ++i) { 2138 mirror::ArtField* cur = fields->Get(i); 2139 if (cur->GetOffset().Int32Value() == offset.Int32Value()) { 2140 LOG(ERROR) << (is_static ? "Static " : "") << "field in the live stack is " 2141 << PrettyField(cur); 2142 break; 2143 } 2144 } 2145 } else { 2146 mirror::ObjectArray<mirror::Object>* object_array = 2147 obj->AsObjectArray<mirror::Object>(); 2148 for (int32_t i = 0; i < object_array->GetLength(); ++i) { 2149 if (object_array->Get(i) == ref) { 2150 LOG(ERROR) << (is_static ? "Static " : "") << "obj[" << i << "] = ref"; 2151 } 2152 } 2153 } 2154 2155 *failed_ = true; 2156 } 2157 } 2158 } 2159 } 2160 2161 private: 2162 Heap* const heap_; 2163 bool* const failed_; 2164}; 2165 2166class VerifyLiveStackReferences { 2167 public: 2168 explicit VerifyLiveStackReferences(Heap* heap) 2169 : heap_(heap), 2170 failed_(false) {} 2171 2172 void operator()(mirror::Object* obj) const 2173 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, Locks::heap_bitmap_lock_) { 2174 VerifyReferenceCardVisitor visitor(heap_, const_cast<bool*>(&failed_)); 2175 collector::MarkSweep::VisitObjectReferences(const_cast<mirror::Object*>(obj), visitor, true); 2176 } 2177 2178 bool Failed() const { 2179 return failed_; 2180 } 2181 2182 private: 2183 Heap* const heap_; 2184 bool failed_; 2185}; 2186 2187bool Heap::VerifyMissingCardMarks() { 2188 Thread* self = Thread::Current(); 2189 Locks::mutator_lock_->AssertExclusiveHeld(self); 2190 2191 // We need to sort the live stack since we binary search it. 2192 live_stack_->Sort(); 2193 // Since we sorted the allocation stack content, need to revoke all 2194 // thread-local allocation stacks. 2195 RevokeAllThreadLocalAllocationStacks(self); 2196 VerifyLiveStackReferences visitor(this); 2197 GetLiveBitmap()->Visit(visitor); 2198 2199 // We can verify objects in the live stack since none of these should reference dead objects. 2200 for (mirror::Object** it = live_stack_->Begin(); it != live_stack_->End(); ++it) { 2201 if (!kUseThreadLocalAllocationStack || *it != nullptr) { 2202 visitor(*it); 2203 } 2204 } 2205 2206 if (visitor.Failed()) { 2207 DumpSpaces(); 2208 return false; 2209 } 2210 return true; 2211} 2212 2213void Heap::SwapStacks(Thread* self) { 2214 if (kUseThreadLocalAllocationStack) { 2215 live_stack_->AssertAllZero(); 2216 } 2217 allocation_stack_.swap(live_stack_); 2218} 2219 2220void Heap::RevokeAllThreadLocalAllocationStacks(Thread* self) { 2221 // This must be called only during the pause. 2222 CHECK(Locks::mutator_lock_->IsExclusiveHeld(self)); 2223 MutexLock mu(self, *Locks::runtime_shutdown_lock_); 2224 MutexLock mu2(self, *Locks::thread_list_lock_); 2225 std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList(); 2226 for (Thread* t : thread_list) { 2227 t->RevokeThreadLocalAllocationStack(); 2228 } 2229} 2230 2231void Heap::AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked() { 2232 if (kIsDebugBuild) { 2233 if (bump_pointer_space_ != nullptr) { 2234 bump_pointer_space_->AssertAllThreadLocalBuffersAreRevoked(); 2235 } 2236 } 2237} 2238 2239accounting::ModUnionTable* Heap::FindModUnionTableFromSpace(space::Space* space) { 2240 auto it = mod_union_tables_.find(space); 2241 if (it == mod_union_tables_.end()) { 2242 return nullptr; 2243 } 2244 return it->second; 2245} 2246 2247accounting::RememberedSet* Heap::FindRememberedSetFromSpace(space::Space* space) { 2248 auto it = remembered_sets_.find(space); 2249 if (it == remembered_sets_.end()) { 2250 return nullptr; 2251 } 2252 return it->second; 2253} 2254 2255void Heap::ProcessCards(TimingLogger& timings, bool use_rem_sets) { 2256 // Clear cards and keep track of cards cleared in the mod-union table. 2257 for (const auto& space : continuous_spaces_) { 2258 accounting::ModUnionTable* table = FindModUnionTableFromSpace(space); 2259 accounting::RememberedSet* rem_set = FindRememberedSetFromSpace(space); 2260 if (table != nullptr) { 2261 const char* name = space->IsZygoteSpace() ? "ZygoteModUnionClearCards" : 2262 "ImageModUnionClearCards"; 2263 TimingLogger::ScopedSplit split(name, &timings); 2264 table->ClearCards(); 2265 } else if (use_rem_sets && rem_set != nullptr) { 2266 DCHECK(collector::SemiSpace::kUseRememberedSet && collector_type_ == kCollectorTypeGSS) 2267 << static_cast<int>(collector_type_); 2268 TimingLogger::ScopedSplit split("AllocSpaceRemSetClearCards", &timings); 2269 rem_set->ClearCards(); 2270 } else if (space->GetType() != space::kSpaceTypeBumpPointerSpace) { 2271 TimingLogger::ScopedSplit split("AllocSpaceClearCards", &timings); 2272 // No mod union table for the AllocSpace. Age the cards so that the GC knows that these cards 2273 // were dirty before the GC started. 2274 // TODO: Need to use atomic for the case where aged(cleaning thread) -> dirty(other thread) 2275 // -> clean(cleaning thread). 2276 // The races are we either end up with: Aged card, unaged card. Since we have the checkpoint 2277 // roots and then we scan / update mod union tables after. We will always scan either card. 2278 // If we end up with the non aged card, we scan it it in the pause. 2279 card_table_->ModifyCardsAtomic(space->Begin(), space->End(), AgeCardVisitor(), VoidFunctor()); 2280 } 2281 } 2282} 2283 2284static mirror::Object* IdentityMarkObjectCallback(mirror::Object* obj, void*) { 2285 return obj; 2286} 2287 2288void Heap::PreGcVerification(collector::GarbageCollector* gc) { 2289 ThreadList* thread_list = Runtime::Current()->GetThreadList(); 2290 Thread* self = Thread::Current(); 2291 2292 if (verify_pre_gc_heap_) { 2293 thread_list->SuspendAll(); 2294 { 2295 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2296 if (!VerifyHeapReferences()) { 2297 LOG(FATAL) << "Pre " << gc->GetName() << " heap verification failed"; 2298 } 2299 } 2300 thread_list->ResumeAll(); 2301 } 2302 2303 // Check that all objects which reference things in the live stack are on dirty cards. 2304 if (verify_missing_card_marks_) { 2305 thread_list->SuspendAll(); 2306 { 2307 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2308 SwapStacks(self); 2309 // Sort the live stack so that we can quickly binary search it later. 2310 if (!VerifyMissingCardMarks()) { 2311 LOG(FATAL) << "Pre " << gc->GetName() << " missing card mark verification failed"; 2312 } 2313 SwapStacks(self); 2314 } 2315 thread_list->ResumeAll(); 2316 } 2317 2318 if (verify_mod_union_table_) { 2319 thread_list->SuspendAll(); 2320 ReaderMutexLock reader_lock(self, *Locks::heap_bitmap_lock_); 2321 for (const auto& table_pair : mod_union_tables_) { 2322 accounting::ModUnionTable* mod_union_table = table_pair.second; 2323 mod_union_table->UpdateAndMarkReferences(IdentityMarkObjectCallback, nullptr); 2324 mod_union_table->Verify(); 2325 } 2326 thread_list->ResumeAll(); 2327 } 2328} 2329 2330void Heap::PreSweepingGcVerification(collector::GarbageCollector* gc) { 2331 // Called before sweeping occurs since we want to make sure we are not going so reclaim any 2332 // reachable objects. 2333 if (verify_post_gc_heap_) { 2334 Thread* self = Thread::Current(); 2335 CHECK_NE(self->GetState(), kRunnable); 2336 { 2337 WriterMutexLock mu(self, *Locks::heap_bitmap_lock_); 2338 // Swapping bound bitmaps does nothing. 2339 gc->SwapBitmaps(); 2340 if (!VerifyHeapReferences()) { 2341 LOG(FATAL) << "Pre sweeping " << gc->GetName() << " GC verification failed"; 2342 } 2343 gc->SwapBitmaps(); 2344 } 2345 } 2346} 2347 2348void Heap::PostGcVerification(collector::GarbageCollector* gc) { 2349 if (verify_system_weaks_) { 2350 Thread* self = Thread::Current(); 2351 ReaderMutexLock mu(self, *Locks::heap_bitmap_lock_); 2352 collector::MarkSweep* mark_sweep = down_cast<collector::MarkSweep*>(gc); 2353 mark_sweep->VerifySystemWeaks(); 2354 } 2355} 2356 2357void Heap::PreGcRosAllocVerification(TimingLogger* timings) { 2358 if (verify_pre_gc_rosalloc_) { 2359 TimingLogger::ScopedSplit split("PreGcRosAllocVerification", timings); 2360 for (const auto& space : continuous_spaces_) { 2361 if (space->IsRosAllocSpace()) { 2362 VLOG(heap) << "PreGcRosAllocVerification : " << space->GetName(); 2363 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2364 rosalloc_space->Verify(); 2365 } 2366 } 2367 } 2368} 2369 2370void Heap::PostGcRosAllocVerification(TimingLogger* timings) { 2371 if (verify_post_gc_rosalloc_) { 2372 TimingLogger::ScopedSplit split("PostGcRosAllocVerification", timings); 2373 for (const auto& space : continuous_spaces_) { 2374 if (space->IsRosAllocSpace()) { 2375 VLOG(heap) << "PostGcRosAllocVerification : " << space->GetName(); 2376 space::RosAllocSpace* rosalloc_space = space->AsRosAllocSpace(); 2377 rosalloc_space->Verify(); 2378 } 2379 } 2380 } 2381} 2382 2383collector::GcType Heap::WaitForGcToComplete(Thread* self) { 2384 ScopedThreadStateChange tsc(self, kWaitingForGcToComplete); 2385 MutexLock mu(self, *gc_complete_lock_); 2386 return WaitForGcToCompleteLocked(self); 2387} 2388 2389collector::GcType Heap::WaitForGcToCompleteLocked(Thread* self) { 2390 collector::GcType last_gc_type = collector::kGcTypeNone; 2391 uint64_t wait_start = NanoTime(); 2392 while (collector_type_running_ != kCollectorTypeNone) { 2393 ATRACE_BEGIN("GC: Wait For Completion"); 2394 // We must wait, change thread state then sleep on gc_complete_cond_; 2395 gc_complete_cond_->Wait(self); 2396 last_gc_type = last_gc_type_; 2397 ATRACE_END(); 2398 } 2399 uint64_t wait_time = NanoTime() - wait_start; 2400 total_wait_time_ += wait_time; 2401 if (wait_time > long_pause_log_threshold_) { 2402 LOG(INFO) << "WaitForGcToComplete blocked for " << PrettyDuration(wait_time); 2403 } 2404 return last_gc_type; 2405} 2406 2407void Heap::DumpForSigQuit(std::ostream& os) { 2408 os << "Heap: " << GetPercentFree() << "% free, " << PrettySize(GetBytesAllocated()) << "/" 2409 << PrettySize(GetTotalMemory()) << "; " << GetObjectsAllocated() << " objects\n"; 2410 DumpGcPerformanceInfo(os); 2411} 2412 2413size_t Heap::GetPercentFree() { 2414 return static_cast<size_t>(100.0f * static_cast<float>(GetFreeMemory()) / GetTotalMemory()); 2415} 2416 2417void Heap::SetIdealFootprint(size_t max_allowed_footprint) { 2418 if (max_allowed_footprint > GetMaxMemory()) { 2419 VLOG(gc) << "Clamp target GC heap from " << PrettySize(max_allowed_footprint) << " to " 2420 << PrettySize(GetMaxMemory()); 2421 max_allowed_footprint = GetMaxMemory(); 2422 } 2423 max_allowed_footprint_ = max_allowed_footprint; 2424} 2425 2426bool Heap::IsMovableObject(const mirror::Object* obj) const { 2427 if (kMovingCollector) { 2428 DCHECK(!IsInTempSpace(obj)); 2429 if (bump_pointer_space_->HasAddress(obj)) { 2430 return true; 2431 } 2432 // TODO: Refactor this logic into the space itself? 2433 // Objects in the main space are only copied during background -> foreground transitions or 2434 // visa versa. 2435 if (main_space_ != nullptr && main_space_->HasAddress(obj) && 2436 (IsCompactingGC(background_collector_type_) || 2437 IsCompactingGC(post_zygote_collector_type_))) { 2438 return true; 2439 } 2440 } 2441 return false; 2442} 2443 2444bool Heap::IsInTempSpace(const mirror::Object* obj) const { 2445 if (temp_space_->HasAddress(obj) && !temp_space_->Contains(obj)) { 2446 return true; 2447 } 2448 return false; 2449} 2450 2451void Heap::UpdateMaxNativeFootprint() { 2452 size_t native_size = native_bytes_allocated_; 2453 // TODO: Tune the native heap utilization to be a value other than the java heap utilization. 2454 size_t target_size = native_size / GetTargetHeapUtilization(); 2455 if (target_size > native_size + max_free_) { 2456 target_size = native_size + max_free_; 2457 } else if (target_size < native_size + min_free_) { 2458 target_size = native_size + min_free_; 2459 } 2460 native_footprint_gc_watermark_ = target_size; 2461 native_footprint_limit_ = 2 * target_size - native_size; 2462} 2463 2464void Heap::GrowForUtilization(collector::GcType gc_type, uint64_t gc_duration) { 2465 // We know what our utilization is at this moment. 2466 // This doesn't actually resize any memory. It just lets the heap grow more when necessary. 2467 const size_t bytes_allocated = GetBytesAllocated(); 2468 last_gc_size_ = bytes_allocated; 2469 last_gc_time_ns_ = NanoTime(); 2470 size_t target_size; 2471 if (gc_type != collector::kGcTypeSticky) { 2472 // Grow the heap for non sticky GC. 2473 target_size = bytes_allocated / GetTargetHeapUtilization(); 2474 if (target_size > bytes_allocated + max_free_) { 2475 target_size = bytes_allocated + max_free_; 2476 } else if (target_size < bytes_allocated + min_free_) { 2477 target_size = bytes_allocated + min_free_; 2478 } 2479 native_need_to_run_finalization_ = true; 2480 next_gc_type_ = collector::kGcTypeSticky; 2481 } else { 2482 // Based on how close the current heap size is to the target size, decide 2483 // whether or not to do a partial or sticky GC next. 2484 if (bytes_allocated + min_free_ <= max_allowed_footprint_) { 2485 next_gc_type_ = collector::kGcTypeSticky; 2486 } else { 2487 next_gc_type_ = have_zygote_space_ ? collector::kGcTypePartial : collector::kGcTypeFull; 2488 } 2489 // If we have freed enough memory, shrink the heap back down. 2490 if (bytes_allocated + max_free_ < max_allowed_footprint_) { 2491 target_size = bytes_allocated + max_free_; 2492 } else { 2493 target_size = std::max(bytes_allocated, max_allowed_footprint_); 2494 } 2495 } 2496 if (!ignore_max_footprint_) { 2497 SetIdealFootprint(target_size); 2498 if (IsGcConcurrent()) { 2499 // Calculate when to perform the next ConcurrentGC. 2500 // Calculate the estimated GC duration. 2501 const double gc_duration_seconds = NsToMs(gc_duration) / 1000.0; 2502 // Estimate how many remaining bytes we will have when we need to start the next GC. 2503 size_t remaining_bytes = allocation_rate_ * gc_duration_seconds; 2504 remaining_bytes = std::min(remaining_bytes, kMaxConcurrentRemainingBytes); 2505 remaining_bytes = std::max(remaining_bytes, kMinConcurrentRemainingBytes); 2506 if (UNLIKELY(remaining_bytes > max_allowed_footprint_)) { 2507 // A never going to happen situation that from the estimated allocation rate we will exceed 2508 // the applications entire footprint with the given estimated allocation rate. Schedule 2509 // another GC nearly straight away. 2510 remaining_bytes = kMinConcurrentRemainingBytes; 2511 } 2512 DCHECK_LE(remaining_bytes, max_allowed_footprint_); 2513 DCHECK_LE(max_allowed_footprint_, growth_limit_); 2514 // Start a concurrent GC when we get close to the estimated remaining bytes. When the 2515 // allocation rate is very high, remaining_bytes could tell us that we should start a GC 2516 // right away. 2517 concurrent_start_bytes_ = std::max(max_allowed_footprint_ - remaining_bytes, bytes_allocated); 2518 } 2519 } 2520} 2521 2522void Heap::ClearGrowthLimit() { 2523 growth_limit_ = capacity_; 2524 non_moving_space_->ClearGrowthLimit(); 2525} 2526 2527void Heap::AddFinalizerReference(Thread* self, mirror::Object* object) { 2528 ScopedObjectAccess soa(self); 2529 ScopedLocalRef<jobject> arg(self->GetJniEnv(), soa.AddLocalReference<jobject>(object)); 2530 jvalue args[1]; 2531 args[0].l = arg.get(); 2532 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_FinalizerReference_add, args); 2533} 2534 2535void Heap::EnqueueClearedReferences() { 2536 Thread* self = Thread::Current(); 2537 Locks::mutator_lock_->AssertNotHeld(self); 2538 if (!cleared_references_.IsEmpty()) { 2539 // When a runtime isn't started there are no reference queues to care about so ignore. 2540 if (LIKELY(Runtime::Current()->IsStarted())) { 2541 ScopedObjectAccess soa(self); 2542 ScopedLocalRef<jobject> arg(self->GetJniEnv(), 2543 soa.AddLocalReference<jobject>(cleared_references_.GetList())); 2544 jvalue args[1]; 2545 args[0].l = arg.get(); 2546 InvokeWithJValues(soa, nullptr, WellKnownClasses::java_lang_ref_ReferenceQueue_add, args); 2547 } 2548 cleared_references_.Clear(); 2549 } 2550} 2551 2552void Heap::RequestConcurrentGC(Thread* self) { 2553 // Make sure that we can do a concurrent GC. 2554 Runtime* runtime = Runtime::Current(); 2555 if (runtime == NULL || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self) || 2556 self->IsHandlingStackOverflow()) { 2557 return; 2558 } 2559 // We already have a request pending, no reason to start more until we update 2560 // concurrent_start_bytes_. 2561 concurrent_start_bytes_ = std::numeric_limits<size_t>::max(); 2562 JNIEnv* env = self->GetJniEnv(); 2563 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2564 DCHECK(WellKnownClasses::java_lang_Daemons_requestGC != nullptr); 2565 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2566 WellKnownClasses::java_lang_Daemons_requestGC); 2567 CHECK(!env->ExceptionCheck()); 2568} 2569 2570void Heap::ConcurrentGC(Thread* self) { 2571 if (Runtime::Current()->IsShuttingDown(self)) { 2572 return; 2573 } 2574 // Wait for any GCs currently running to finish. 2575 if (WaitForGcToComplete(self) == collector::kGcTypeNone) { 2576 // If the we can't run the GC type we wanted to run, find the next appropriate one and try that 2577 // instead. E.g. can't do partial, so do full instead. 2578 if (CollectGarbageInternal(next_gc_type_, kGcCauseBackground, false) == 2579 collector::kGcTypeNone) { 2580 for (collector::GcType gc_type : gc_plan_) { 2581 // Attempt to run the collector, if we succeed, we are done. 2582 if (gc_type > next_gc_type_ && 2583 CollectGarbageInternal(gc_type, kGcCauseBackground, false) != collector::kGcTypeNone) { 2584 break; 2585 } 2586 } 2587 } 2588 } 2589} 2590 2591void Heap::RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) { 2592 Thread* self = Thread::Current(); 2593 { 2594 MutexLock mu(self, *heap_trim_request_lock_); 2595 if (desired_collector_type_ == desired_collector_type) { 2596 return; 2597 } 2598 heap_transition_target_time_ = std::max(heap_transition_target_time_, NanoTime() + delta_time); 2599 desired_collector_type_ = desired_collector_type; 2600 } 2601 SignalHeapTrimDaemon(self); 2602} 2603 2604void Heap::RequestHeapTrim() { 2605 // GC completed and now we must decide whether to request a heap trim (advising pages back to the 2606 // kernel) or not. Issuing a request will also cause trimming of the libc heap. As a trim scans 2607 // a space it will hold its lock and can become a cause of jank. 2608 // Note, the large object space self trims and the Zygote space was trimmed and unchanging since 2609 // forking. 2610 2611 // We don't have a good measure of how worthwhile a trim might be. We can't use the live bitmap 2612 // because that only marks object heads, so a large array looks like lots of empty space. We 2613 // don't just call dlmalloc all the time, because the cost of an _attempted_ trim is proportional 2614 // to utilization (which is probably inversely proportional to how much benefit we can expect). 2615 // We could try mincore(2) but that's only a measure of how many pages we haven't given away, 2616 // not how much use we're making of those pages. 2617 2618 Thread* self = Thread::Current(); 2619 Runtime* runtime = Runtime::Current(); 2620 if (runtime == nullptr || !runtime->IsFinishedStarting() || runtime->IsShuttingDown(self)) { 2621 // Heap trimming isn't supported without a Java runtime or Daemons (such as at dex2oat time) 2622 // Also: we do not wish to start a heap trim if the runtime is shutting down (a racy check 2623 // as we don't hold the lock while requesting the trim). 2624 return; 2625 } 2626 2627 // Request a heap trim only if we do not currently care about pause times. 2628 if (!CareAboutPauseTimes()) { 2629 { 2630 MutexLock mu(self, *heap_trim_request_lock_); 2631 if (last_trim_time_ + kHeapTrimWait >= NanoTime()) { 2632 // We have done a heap trim in the last kHeapTrimWait nanosecs, don't request another one 2633 // just yet. 2634 return; 2635 } 2636 heap_trim_request_pending_ = true; 2637 } 2638 // Notify the daemon thread which will actually do the heap trim. 2639 SignalHeapTrimDaemon(self); 2640 } 2641} 2642 2643void Heap::SignalHeapTrimDaemon(Thread* self) { 2644 JNIEnv* env = self->GetJniEnv(); 2645 DCHECK(WellKnownClasses::java_lang_Daemons != nullptr); 2646 DCHECK(WellKnownClasses::java_lang_Daemons_requestHeapTrim != nullptr); 2647 env->CallStaticVoidMethod(WellKnownClasses::java_lang_Daemons, 2648 WellKnownClasses::java_lang_Daemons_requestHeapTrim); 2649 CHECK(!env->ExceptionCheck()); 2650} 2651 2652void Heap::RevokeThreadLocalBuffers(Thread* thread) { 2653 if (rosalloc_space_ != nullptr) { 2654 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2655 } 2656 if (bump_pointer_space_ != nullptr) { 2657 bump_pointer_space_->RevokeThreadLocalBuffers(thread); 2658 } 2659} 2660 2661void Heap::RevokeRosAllocThreadLocalBuffers(Thread* thread) { 2662 if (rosalloc_space_ != nullptr) { 2663 rosalloc_space_->RevokeThreadLocalBuffers(thread); 2664 } 2665} 2666 2667void Heap::RevokeAllThreadLocalBuffers() { 2668 if (rosalloc_space_ != nullptr) { 2669 rosalloc_space_->RevokeAllThreadLocalBuffers(); 2670 } 2671 if (bump_pointer_space_ != nullptr) { 2672 bump_pointer_space_->RevokeAllThreadLocalBuffers(); 2673 } 2674} 2675 2676bool Heap::IsGCRequestPending() const { 2677 return concurrent_start_bytes_ != std::numeric_limits<size_t>::max(); 2678} 2679 2680void Heap::RunFinalization(JNIEnv* env) { 2681 // Can't do this in WellKnownClasses::Init since System is not properly set up at that point. 2682 if (WellKnownClasses::java_lang_System_runFinalization == nullptr) { 2683 CHECK(WellKnownClasses::java_lang_System != nullptr); 2684 WellKnownClasses::java_lang_System_runFinalization = 2685 CacheMethod(env, WellKnownClasses::java_lang_System, true, "runFinalization", "()V"); 2686 CHECK(WellKnownClasses::java_lang_System_runFinalization != nullptr); 2687 } 2688 env->CallStaticVoidMethod(WellKnownClasses::java_lang_System, 2689 WellKnownClasses::java_lang_System_runFinalization); 2690} 2691 2692void Heap::RegisterNativeAllocation(JNIEnv* env, int bytes) { 2693 Thread* self = ThreadForEnv(env); 2694 if (native_need_to_run_finalization_) { 2695 RunFinalization(env); 2696 UpdateMaxNativeFootprint(); 2697 native_need_to_run_finalization_ = false; 2698 } 2699 // Total number of native bytes allocated. 2700 native_bytes_allocated_.FetchAndAdd(bytes); 2701 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_gc_watermark_) { 2702 collector::GcType gc_type = have_zygote_space_ ? collector::kGcTypePartial : 2703 collector::kGcTypeFull; 2704 2705 // The second watermark is higher than the gc watermark. If you hit this it means you are 2706 // allocating native objects faster than the GC can keep up with. 2707 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2708 if (WaitForGcToComplete(self) != collector::kGcTypeNone) { 2709 // Just finished a GC, attempt to run finalizers. 2710 RunFinalization(env); 2711 CHECK(!env->ExceptionCheck()); 2712 } 2713 // If we still are over the watermark, attempt a GC for alloc and run finalizers. 2714 if (static_cast<size_t>(native_bytes_allocated_) > native_footprint_limit_) { 2715 CollectGarbageInternal(gc_type, kGcCauseForNativeAlloc, false); 2716 RunFinalization(env); 2717 native_need_to_run_finalization_ = false; 2718 CHECK(!env->ExceptionCheck()); 2719 } 2720 // We have just run finalizers, update the native watermark since it is very likely that 2721 // finalizers released native managed allocations. 2722 UpdateMaxNativeFootprint(); 2723 } else if (!IsGCRequestPending()) { 2724 if (IsGcConcurrent()) { 2725 RequestConcurrentGC(self); 2726 } else { 2727 CollectGarbageInternal(gc_type, kGcCauseForAlloc, false); 2728 } 2729 } 2730 } 2731} 2732 2733void Heap::RegisterNativeFree(JNIEnv* env, int bytes) { 2734 int expected_size, new_size; 2735 do { 2736 expected_size = native_bytes_allocated_.Load(); 2737 new_size = expected_size - bytes; 2738 if (UNLIKELY(new_size < 0)) { 2739 ScopedObjectAccess soa(env); 2740 env->ThrowNew(WellKnownClasses::java_lang_RuntimeException, 2741 StringPrintf("Attempted to free %d native bytes with only %d native bytes " 2742 "registered as allocated", bytes, expected_size).c_str()); 2743 break; 2744 } 2745 } while (!native_bytes_allocated_.CompareAndSwap(expected_size, new_size)); 2746} 2747 2748size_t Heap::GetTotalMemory() const { 2749 size_t ret = 0; 2750 for (const auto& space : continuous_spaces_) { 2751 // Currently don't include the image space. 2752 if (!space->IsImageSpace()) { 2753 ret += space->Size(); 2754 } 2755 } 2756 for (const auto& space : discontinuous_spaces_) { 2757 if (space->IsLargeObjectSpace()) { 2758 ret += space->AsLargeObjectSpace()->GetBytesAllocated(); 2759 } 2760 } 2761 return ret; 2762} 2763 2764void Heap::AddModUnionTable(accounting::ModUnionTable* mod_union_table) { 2765 DCHECK(mod_union_table != nullptr); 2766 mod_union_tables_.Put(mod_union_table->GetSpace(), mod_union_table); 2767} 2768 2769void Heap::CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) { 2770 CHECK(c == NULL || (c->IsClassClass() && byte_count >= sizeof(mirror::Class)) || 2771 (c->IsVariableSize() || c->GetObjectSize() == byte_count) || 2772 strlen(ClassHelper(c).GetDescriptor()) == 0); 2773 CHECK_GE(byte_count, sizeof(mirror::Object)); 2774} 2775 2776void Heap::AddRememberedSet(accounting::RememberedSet* remembered_set) { 2777 CHECK(remembered_set != nullptr); 2778 space::Space* space = remembered_set->GetSpace(); 2779 CHECK(space != nullptr); 2780 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2781 remembered_sets_.Put(space, remembered_set); 2782 CHECK(remembered_sets_.find(space) != remembered_sets_.end()); 2783} 2784 2785void Heap::RemoveRememberedSet(space::Space* space) { 2786 CHECK(space != nullptr); 2787 auto it = remembered_sets_.find(space); 2788 CHECK(it != remembered_sets_.end()); 2789 remembered_sets_.erase(it); 2790 CHECK(remembered_sets_.find(space) == remembered_sets_.end()); 2791} 2792 2793} // namespace gc 2794} // namespace art 2795