1 /* 2 * Copyright (C) 2008 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 #ifndef ART_RUNTIME_GC_HEAP_H_ 18 #define ART_RUNTIME_GC_HEAP_H_ 19 20 #include <iosfwd> 21 #include <string> 22 #include <unordered_set> 23 #include <vector> 24 25 #include "allocator_type.h" 26 #include "arch/instruction_set.h" 27 #include "atomic.h" 28 #include "base/time_utils.h" 29 #include "gc/accounting/atomic_stack.h" 30 #include "gc/accounting/card_table.h" 31 #include "gc/accounting/read_barrier_table.h" 32 #include "gc/gc_cause.h" 33 #include "gc/collector/gc_type.h" 34 #include "gc/collector_type.h" 35 #include "gc/space/large_object_space.h" 36 #include "globals.h" 37 #include "object_callbacks.h" 38 #include "offsets.h" 39 #include "process_state.h" 40 #include "safe_map.h" 41 #include "verify_object.h" 42 43 namespace art { 44 45 class ConditionVariable; 46 class Mutex; 47 class StackVisitor; 48 class Thread; 49 class ThreadPool; 50 class TimingLogger; 51 52 namespace mirror { 53 class Class; 54 class Object; 55 } // namespace mirror 56 57 namespace gc { 58 59 class AllocRecordObjectMap; 60 class ReferenceProcessor; 61 class TaskProcessor; 62 63 namespace accounting { 64 class HeapBitmap; 65 class ModUnionTable; 66 class RememberedSet; 67 } // namespace accounting 68 69 namespace collector { 70 class ConcurrentCopying; 71 class GarbageCollector; 72 class MarkCompact; 73 class MarkSweep; 74 class SemiSpace; 75 } // namespace collector 76 77 namespace allocator { 78 class RosAlloc; 79 } // namespace allocator 80 81 namespace space { 82 class AllocSpace; 83 class BumpPointerSpace; 84 class ContinuousMemMapAllocSpace; 85 class DiscontinuousSpace; 86 class DlMallocSpace; 87 class ImageSpace; 88 class LargeObjectSpace; 89 class MallocSpace; 90 class RegionSpace; 91 class RosAllocSpace; 92 class Space; 93 class ZygoteSpace; 94 } // namespace space 95 96 class AgeCardVisitor { 97 public: 98 uint8_t operator()(uint8_t card) const { 99 return (card == accounting::CardTable::kCardDirty) ? card - 1 : 0; 100 } 101 }; 102 103 enum HomogeneousSpaceCompactResult { 104 // Success. 105 kSuccess, 106 // Reject due to disabled moving GC. 107 kErrorReject, 108 // Unsupported due to the current configuration. 109 kErrorUnsupported, 110 // System is shutting down. 111 kErrorVMShuttingDown, 112 }; 113 114 // If true, use rosalloc/RosAllocSpace instead of dlmalloc/DlMallocSpace 115 static constexpr bool kUseRosAlloc = true; 116 117 // If true, use thread-local allocation stack. 118 static constexpr bool kUseThreadLocalAllocationStack = true; 119 120 class Heap { 121 public: 122 // If true, measure the total allocation time. 123 static constexpr size_t kDefaultStartingSize = kPageSize; 124 static constexpr size_t kDefaultInitialSize = 2 * MB; 125 static constexpr size_t kDefaultMaximumSize = 256 * MB; 126 static constexpr size_t kDefaultNonMovingSpaceCapacity = 64 * MB; 127 static constexpr size_t kDefaultMaxFree = 2 * MB; 128 static constexpr size_t kDefaultMinFree = kDefaultMaxFree / 4; 129 static constexpr size_t kDefaultLongPauseLogThreshold = MsToNs(5); 130 static constexpr size_t kDefaultLongGCLogThreshold = MsToNs(100); 131 static constexpr size_t kDefaultTLABSize = 256 * KB; 132 static constexpr double kDefaultTargetUtilization = 0.5; 133 static constexpr double kDefaultHeapGrowthMultiplier = 2.0; 134 // Primitive arrays larger than this size are put in the large object space. 135 static constexpr size_t kDefaultLargeObjectThreshold = 3 * kPageSize; 136 // Whether or not parallel GC is enabled. If not, then we never create the thread pool. 137 static constexpr bool kDefaultEnableParallelGC = false; 138 139 // Whether or not we use the free list large object space. Only use it if USE_ART_LOW_4G_ALLOCATOR 140 // since this means that we have to use the slow msync loop in MemMap::MapAnonymous. 141 static constexpr space::LargeObjectSpaceType kDefaultLargeObjectSpaceType = 142 USE_ART_LOW_4G_ALLOCATOR ? 143 space::LargeObjectSpaceType::kFreeList 144 : space::LargeObjectSpaceType::kMap; 145 146 // Used so that we don't overflow the allocation time atomic integer. 147 static constexpr size_t kTimeAdjust = 1024; 148 149 // How often we allow heap trimming to happen (nanoseconds). 150 static constexpr uint64_t kHeapTrimWait = MsToNs(5000); 151 // How long we wait after a transition request to perform a collector transition (nanoseconds). 152 static constexpr uint64_t kCollectorTransitionWait = MsToNs(5000); 153 154 // Create a heap with the requested sizes. The possible empty 155 // image_file_names names specify Spaces to load based on 156 // ImageWriter output. 157 Heap(size_t initial_size, 158 size_t growth_limit, 159 size_t min_free, 160 size_t max_free, 161 double target_utilization, 162 double foreground_heap_growth_multiplier, 163 size_t capacity, 164 size_t non_moving_space_capacity, 165 const std::string& original_image_file_name, 166 InstructionSet image_instruction_set, 167 CollectorType foreground_collector_type, 168 CollectorType background_collector_type, 169 space::LargeObjectSpaceType large_object_space_type, 170 size_t large_object_threshold, 171 size_t parallel_gc_threads, 172 size_t conc_gc_threads, 173 bool low_memory_mode, 174 size_t long_pause_threshold, 175 size_t long_gc_threshold, 176 bool ignore_max_footprint, 177 bool use_tlab, 178 bool verify_pre_gc_heap, 179 bool verify_pre_sweeping_heap, 180 bool verify_post_gc_heap, 181 bool verify_pre_gc_rosalloc, 182 bool verify_pre_sweeping_rosalloc, 183 bool verify_post_gc_rosalloc, 184 bool gc_stress_mode, 185 bool use_homogeneous_space_compaction, 186 uint64_t min_interval_homogeneous_space_compaction_by_oom); 187 188 ~Heap(); 189 190 // Allocates and initializes storage for an object instance. 191 template <bool kInstrumented, typename PreFenceVisitor> 192 mirror::Object* AllocObject(Thread* self, 193 mirror::Class* klass, 194 size_t num_bytes, 195 const PreFenceVisitor& pre_fence_visitor) 196 SHARED_REQUIRES(Locks::mutator_lock_) 197 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !*backtrace_lock_, 198 !Roles::uninterruptible_) { 199 return AllocObjectWithAllocator<kInstrumented, true>( 200 self, klass, num_bytes, GetCurrentAllocator(), pre_fence_visitor); 201 } 202 203 template <bool kInstrumented, typename PreFenceVisitor> 204 mirror::Object* AllocNonMovableObject(Thread* self, 205 mirror::Class* klass, 206 size_t num_bytes, 207 const PreFenceVisitor& pre_fence_visitor) 208 SHARED_REQUIRES(Locks::mutator_lock_) 209 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !*backtrace_lock_, 210 !Roles::uninterruptible_) { 211 return AllocObjectWithAllocator<kInstrumented, true>( 212 self, klass, num_bytes, GetCurrentNonMovingAllocator(), pre_fence_visitor); 213 } 214 215 template <bool kInstrumented, bool kCheckLargeObject, typename PreFenceVisitor> 216 ALWAYS_INLINE mirror::Object* AllocObjectWithAllocator(Thread* self, 217 mirror::Class* klass, 218 size_t byte_count, 219 AllocatorType allocator, 220 const PreFenceVisitor& pre_fence_visitor) 221 SHARED_REQUIRES(Locks::mutator_lock_) 222 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !*backtrace_lock_, 223 !Roles::uninterruptible_); 224 225 AllocatorType GetCurrentAllocator() const { 226 return current_allocator_; 227 } 228 229 AllocatorType GetCurrentNonMovingAllocator() const { 230 return current_non_moving_allocator_; 231 } 232 233 // Visit all of the live objects in the heap. 234 void VisitObjects(ObjectCallback callback, void* arg) 235 SHARED_REQUIRES(Locks::mutator_lock_) 236 REQUIRES(!Locks::heap_bitmap_lock_, !*gc_complete_lock_); 237 void VisitObjectsPaused(ObjectCallback callback, void* arg) 238 REQUIRES(Locks::mutator_lock_, !Locks::heap_bitmap_lock_, !*gc_complete_lock_); 239 240 void CheckPreconditionsForAllocObject(mirror::Class* c, size_t byte_count) 241 SHARED_REQUIRES(Locks::mutator_lock_); 242 243 void RegisterNativeAllocation(JNIEnv* env, size_t bytes) 244 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !native_histogram_lock_); 245 void RegisterNativeFree(JNIEnv* env, size_t bytes) 246 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !native_histogram_lock_); 247 248 // Change the allocator, updates entrypoints. 249 void ChangeAllocator(AllocatorType allocator) 250 REQUIRES(Locks::mutator_lock_, !Locks::runtime_shutdown_lock_); 251 252 // Transition the garbage collector during runtime, may copy objects from one space to another. 253 void TransitionCollector(CollectorType collector_type) REQUIRES(!*gc_complete_lock_); 254 255 // Change the collector to be one of the possible options (MS, CMS, SS). 256 void ChangeCollector(CollectorType collector_type) 257 REQUIRES(Locks::mutator_lock_); 258 259 // The given reference is believed to be to an object in the Java heap, check the soundness of it. 260 // TODO: NO_THREAD_SAFETY_ANALYSIS since we call this everywhere and it is impossible to find a 261 // proper lock ordering for it. 262 void VerifyObjectBody(mirror::Object* o) NO_THREAD_SAFETY_ANALYSIS; 263 264 // Check sanity of all live references. 265 void VerifyHeap() REQUIRES(!Locks::heap_bitmap_lock_); 266 // Returns how many failures occured. 267 size_t VerifyHeapReferences(bool verify_referents = true) 268 REQUIRES(Locks::mutator_lock_, !*gc_complete_lock_); 269 bool VerifyMissingCardMarks() 270 REQUIRES(Locks::heap_bitmap_lock_, Locks::mutator_lock_); 271 272 // A weaker test than IsLiveObject or VerifyObject that doesn't require the heap lock, 273 // and doesn't abort on error, allowing the caller to report more 274 // meaningful diagnostics. 275 bool IsValidObjectAddress(const mirror::Object* obj) const SHARED_REQUIRES(Locks::mutator_lock_); 276 277 // Faster alternative to IsHeapAddress since finding if an object is in the large object space is 278 // very slow. 279 bool IsNonDiscontinuousSpaceHeapAddress(const mirror::Object* obj) const 280 SHARED_REQUIRES(Locks::mutator_lock_); 281 282 // Returns true if 'obj' is a live heap object, false otherwise (including for invalid addresses). 283 // Requires the heap lock to be held. 284 bool IsLiveObjectLocked(mirror::Object* obj, 285 bool search_allocation_stack = true, 286 bool search_live_stack = true, 287 bool sorted = false) 288 SHARED_REQUIRES(Locks::heap_bitmap_lock_, Locks::mutator_lock_); 289 290 // Returns true if there is any chance that the object (obj) will move. 291 bool IsMovableObject(const mirror::Object* obj) const SHARED_REQUIRES(Locks::mutator_lock_); 292 293 // Enables us to compacting GC until objects are released. 294 void IncrementDisableMovingGC(Thread* self) REQUIRES(!*gc_complete_lock_); 295 void DecrementDisableMovingGC(Thread* self) REQUIRES(!*gc_complete_lock_); 296 297 // Temporarily disable thread flip for JNI critical calls. 298 void IncrementDisableThreadFlip(Thread* self) REQUIRES(!*thread_flip_lock_); 299 void DecrementDisableThreadFlip(Thread* self) REQUIRES(!*thread_flip_lock_); 300 void ThreadFlipBegin(Thread* self) REQUIRES(!*thread_flip_lock_); 301 void ThreadFlipEnd(Thread* self) REQUIRES(!*thread_flip_lock_); 302 303 // Clear all of the mark bits, doesn't clear bitmaps which have the same live bits as mark bits. 304 // Mutator lock is required for GetContinuousSpaces. 305 void ClearMarkedObjects() 306 REQUIRES(Locks::heap_bitmap_lock_) 307 SHARED_REQUIRES(Locks::mutator_lock_); 308 309 // Initiates an explicit garbage collection. 310 void CollectGarbage(bool clear_soft_references) 311 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_); 312 313 // Does a concurrent GC, should only be called by the GC daemon thread 314 // through runtime. 315 void ConcurrentGC(Thread* self, bool force_full) 316 REQUIRES(!Locks::runtime_shutdown_lock_, !*gc_complete_lock_, !*pending_task_lock_); 317 318 // Implements VMDebug.countInstancesOfClass and JDWP VM_InstanceCount. 319 // The boolean decides whether to use IsAssignableFrom or == when comparing classes. 320 void CountInstances(const std::vector<mirror::Class*>& classes, 321 bool use_is_assignable_from, 322 uint64_t* counts) 323 REQUIRES(!Locks::heap_bitmap_lock_, !*gc_complete_lock_) 324 SHARED_REQUIRES(Locks::mutator_lock_); 325 // Implements JDWP RT_Instances. 326 void GetInstances(mirror::Class* c, int32_t max_count, std::vector<mirror::Object*>& instances) 327 REQUIRES(!Locks::heap_bitmap_lock_, !*gc_complete_lock_) 328 SHARED_REQUIRES(Locks::mutator_lock_); 329 // Implements JDWP OR_ReferringObjects. 330 void GetReferringObjects(mirror::Object* o, 331 int32_t max_count, 332 std::vector<mirror::Object*>& referring_objects) 333 REQUIRES(!Locks::heap_bitmap_lock_, !*gc_complete_lock_) 334 SHARED_REQUIRES(Locks::mutator_lock_); 335 336 // Removes the growth limit on the alloc space so it may grow to its maximum capacity. Used to 337 // implement dalvik.system.VMRuntime.clearGrowthLimit. 338 void ClearGrowthLimit(); 339 340 // Make the current growth limit the new maximum capacity, unmaps pages at the end of spaces 341 // which will never be used. Used to implement dalvik.system.VMRuntime.clampGrowthLimit. 342 void ClampGrowthLimit() REQUIRES(!Locks::heap_bitmap_lock_); 343 344 // Target ideal heap utilization ratio, implements 345 // dalvik.system.VMRuntime.getTargetHeapUtilization. 346 double GetTargetHeapUtilization() const { 347 return target_utilization_; 348 } 349 350 // Data structure memory usage tracking. 351 void RegisterGCAllocation(size_t bytes); 352 void RegisterGCDeAllocation(size_t bytes); 353 354 // Set the heap's private space pointers to be the same as the space based on it's type. Public 355 // due to usage by tests. 356 void SetSpaceAsDefault(space::ContinuousSpace* continuous_space) 357 REQUIRES(!Locks::heap_bitmap_lock_); 358 void AddSpace(space::Space* space) 359 REQUIRES(!Locks::heap_bitmap_lock_) 360 REQUIRES(Locks::mutator_lock_); 361 void RemoveSpace(space::Space* space) 362 REQUIRES(!Locks::heap_bitmap_lock_) 363 REQUIRES(Locks::mutator_lock_); 364 365 // Set target ideal heap utilization ratio, implements 366 // dalvik.system.VMRuntime.setTargetHeapUtilization. 367 void SetTargetHeapUtilization(float target); 368 369 // For the alloc space, sets the maximum number of bytes that the heap is allowed to allocate 370 // from the system. Doesn't allow the space to exceed its growth limit. 371 void SetIdealFootprint(size_t max_allowed_footprint); 372 373 // Blocks the caller until the garbage collector becomes idle and returns the type of GC we 374 // waited for. 375 collector::GcType WaitForGcToComplete(GcCause cause, Thread* self) REQUIRES(!*gc_complete_lock_); 376 377 // Update the heap's process state to a new value, may cause compaction to occur. 378 void UpdateProcessState(ProcessState old_process_state, ProcessState new_process_state) 379 REQUIRES(!*pending_task_lock_, !*gc_complete_lock_); 380 381 bool HaveContinuousSpaces() const NO_THREAD_SAFETY_ANALYSIS { 382 // No lock since vector empty is thread safe. 383 return !continuous_spaces_.empty(); 384 } 385 386 const std::vector<space::ContinuousSpace*>& GetContinuousSpaces() const 387 SHARED_REQUIRES(Locks::mutator_lock_) { 388 return continuous_spaces_; 389 } 390 391 const std::vector<space::DiscontinuousSpace*>& GetDiscontinuousSpaces() const { 392 return discontinuous_spaces_; 393 } 394 395 const collector::Iteration* GetCurrentGcIteration() const { 396 return ¤t_gc_iteration_; 397 } 398 collector::Iteration* GetCurrentGcIteration() { 399 return ¤t_gc_iteration_; 400 } 401 402 // Enable verification of object references when the runtime is sufficiently initialized. 403 void EnableObjectValidation() { 404 verify_object_mode_ = kVerifyObjectSupport; 405 if (verify_object_mode_ > kVerifyObjectModeDisabled) { 406 VerifyHeap(); 407 } 408 } 409 410 // Disable object reference verification for image writing. 411 void DisableObjectValidation() { 412 verify_object_mode_ = kVerifyObjectModeDisabled; 413 } 414 415 // Other checks may be performed if we know the heap should be in a sane state. 416 bool IsObjectValidationEnabled() const { 417 return verify_object_mode_ > kVerifyObjectModeDisabled; 418 } 419 420 // Returns true if low memory mode is enabled. 421 bool IsLowMemoryMode() const { 422 return low_memory_mode_; 423 } 424 425 // Returns the heap growth multiplier, this affects how much we grow the heap after a GC. 426 // Scales heap growth, min free, and max free. 427 double HeapGrowthMultiplier() const; 428 429 // Freed bytes can be negative in cases where we copy objects from a compacted space to a 430 // free-list backed space. 431 void RecordFree(uint64_t freed_objects, int64_t freed_bytes); 432 433 // Record the bytes freed by thread-local buffer revoke. 434 void RecordFreeRevoke(); 435 436 // Must be called if a field of an Object in the heap changes, and before any GC safe-point. 437 // The call is not needed if null is stored in the field. 438 ALWAYS_INLINE void WriteBarrierField(const mirror::Object* dst, 439 MemberOffset offset ATTRIBUTE_UNUSED, 440 const mirror::Object* new_value ATTRIBUTE_UNUSED) { 441 card_table_->MarkCard(dst); 442 } 443 444 // Write barrier for array operations that update many field positions 445 ALWAYS_INLINE void WriteBarrierArray(const mirror::Object* dst, 446 int start_offset ATTRIBUTE_UNUSED, 447 // TODO: element_count or byte_count? 448 size_t length ATTRIBUTE_UNUSED) { 449 card_table_->MarkCard(dst); 450 } 451 452 ALWAYS_INLINE void WriteBarrierEveryFieldOf(const mirror::Object* obj) { 453 card_table_->MarkCard(obj); 454 } 455 456 accounting::CardTable* GetCardTable() const { 457 return card_table_.get(); 458 } 459 460 accounting::ReadBarrierTable* GetReadBarrierTable() const { 461 return rb_table_.get(); 462 } 463 464 void AddFinalizerReference(Thread* self, mirror::Object** object); 465 466 // Returns the number of bytes currently allocated. 467 size_t GetBytesAllocated() const { 468 return num_bytes_allocated_.LoadSequentiallyConsistent(); 469 } 470 471 // Returns the number of objects currently allocated. 472 size_t GetObjectsAllocated() const 473 REQUIRES(!Locks::heap_bitmap_lock_); 474 475 // Returns the total number of objects allocated since the heap was created. 476 uint64_t GetObjectsAllocatedEver() const; 477 478 // Returns the total number of bytes allocated since the heap was created. 479 uint64_t GetBytesAllocatedEver() const; 480 481 // Returns the total number of objects freed since the heap was created. 482 uint64_t GetObjectsFreedEver() const { 483 return total_objects_freed_ever_; 484 } 485 486 // Returns the total number of bytes freed since the heap was created. 487 uint64_t GetBytesFreedEver() const { 488 return total_bytes_freed_ever_; 489 } 490 491 // Implements java.lang.Runtime.maxMemory, returning the maximum amount of memory a program can 492 // consume. For a regular VM this would relate to the -Xmx option and would return -1 if no Xmx 493 // were specified. Android apps start with a growth limit (small heap size) which is 494 // cleared/extended for large apps. 495 size_t GetMaxMemory() const { 496 // There is some race conditions in the allocation code that can cause bytes allocated to 497 // become larger than growth_limit_ in rare cases. 498 return std::max(GetBytesAllocated(), growth_limit_); 499 } 500 501 // Implements java.lang.Runtime.totalMemory, returning approximate amount of memory currently 502 // consumed by an application. 503 size_t GetTotalMemory() const; 504 505 // Returns approximately how much free memory we have until the next GC happens. 506 size_t GetFreeMemoryUntilGC() const { 507 return max_allowed_footprint_ - GetBytesAllocated(); 508 } 509 510 // Returns approximately how much free memory we have until the next OOME happens. 511 size_t GetFreeMemoryUntilOOME() const { 512 return growth_limit_ - GetBytesAllocated(); 513 } 514 515 // Returns how much free memory we have until we need to grow the heap to perform an allocation. 516 // Similar to GetFreeMemoryUntilGC. Implements java.lang.Runtime.freeMemory. 517 size_t GetFreeMemory() const { 518 size_t byte_allocated = num_bytes_allocated_.LoadSequentiallyConsistent(); 519 size_t total_memory = GetTotalMemory(); 520 // Make sure we don't get a negative number. 521 return total_memory - std::min(total_memory, byte_allocated); 522 } 523 524 // get the space that corresponds to an object's address. Current implementation searches all 525 // spaces in turn. If fail_ok is false then failing to find a space will cause an abort. 526 // TODO: consider using faster data structure like binary tree. 527 space::ContinuousSpace* FindContinuousSpaceFromObject(const mirror::Object*, bool fail_ok) const 528 SHARED_REQUIRES(Locks::mutator_lock_); 529 space::DiscontinuousSpace* FindDiscontinuousSpaceFromObject(const mirror::Object*, 530 bool fail_ok) const 531 SHARED_REQUIRES(Locks::mutator_lock_); 532 space::Space* FindSpaceFromObject(const mirror::Object*, bool fail_ok) const 533 SHARED_REQUIRES(Locks::mutator_lock_); 534 535 void DumpForSigQuit(std::ostream& os) REQUIRES(!*gc_complete_lock_, !native_histogram_lock_); 536 537 // Do a pending collector transition. 538 void DoPendingCollectorTransition() REQUIRES(!*gc_complete_lock_); 539 540 // Deflate monitors, ... and trim the spaces. 541 void Trim(Thread* self) REQUIRES(!*gc_complete_lock_); 542 543 void RevokeThreadLocalBuffers(Thread* thread); 544 void RevokeRosAllocThreadLocalBuffers(Thread* thread); 545 void RevokeAllThreadLocalBuffers(); 546 void AssertThreadLocalBuffersAreRevoked(Thread* thread); 547 void AssertAllBumpPointerSpaceThreadLocalBuffersAreRevoked(); 548 void RosAllocVerification(TimingLogger* timings, const char* name) 549 REQUIRES(Locks::mutator_lock_); 550 551 accounting::HeapBitmap* GetLiveBitmap() SHARED_REQUIRES(Locks::heap_bitmap_lock_) { 552 return live_bitmap_.get(); 553 } 554 555 accounting::HeapBitmap* GetMarkBitmap() SHARED_REQUIRES(Locks::heap_bitmap_lock_) { 556 return mark_bitmap_.get(); 557 } 558 559 accounting::ObjectStack* GetLiveStack() SHARED_REQUIRES(Locks::heap_bitmap_lock_) { 560 return live_stack_.get(); 561 } 562 563 void PreZygoteFork() NO_THREAD_SAFETY_ANALYSIS; 564 565 // Mark and empty stack. 566 void FlushAllocStack() 567 SHARED_REQUIRES(Locks::mutator_lock_) 568 REQUIRES(Locks::heap_bitmap_lock_); 569 570 // Revoke all the thread-local allocation stacks. 571 void RevokeAllThreadLocalAllocationStacks(Thread* self) 572 REQUIRES(Locks::mutator_lock_, !Locks::runtime_shutdown_lock_, !Locks::thread_list_lock_); 573 574 // Mark all the objects in the allocation stack in the specified bitmap. 575 // TODO: Refactor? 576 void MarkAllocStack(accounting::SpaceBitmap<kObjectAlignment>* bitmap1, 577 accounting::SpaceBitmap<kObjectAlignment>* bitmap2, 578 accounting::SpaceBitmap<kLargeObjectAlignment>* large_objects, 579 accounting::ObjectStack* stack) 580 SHARED_REQUIRES(Locks::mutator_lock_) 581 REQUIRES(Locks::heap_bitmap_lock_); 582 583 // Mark the specified allocation stack as live. 584 void MarkAllocStackAsLive(accounting::ObjectStack* stack) 585 SHARED_REQUIRES(Locks::mutator_lock_) 586 REQUIRES(Locks::heap_bitmap_lock_); 587 588 // Unbind any bound bitmaps. 589 void UnBindBitmaps() 590 REQUIRES(Locks::heap_bitmap_lock_) 591 SHARED_REQUIRES(Locks::mutator_lock_); 592 593 // Returns the boot image spaces. There may be multiple boot image spaces. 594 const std::vector<space::ImageSpace*>& GetBootImageSpaces() const { 595 return boot_image_spaces_; 596 } 597 598 bool ObjectIsInBootImageSpace(mirror::Object* obj) const 599 SHARED_REQUIRES(Locks::mutator_lock_); 600 601 bool IsInBootImageOatFile(const void* p) const 602 SHARED_REQUIRES(Locks::mutator_lock_); 603 604 void GetBootImagesSize(uint32_t* boot_image_begin, 605 uint32_t* boot_image_end, 606 uint32_t* boot_oat_begin, 607 uint32_t* boot_oat_end); 608 609 // Permenantly disable moving garbage collection. 610 void DisableMovingGc() REQUIRES(!*gc_complete_lock_); 611 612 space::DlMallocSpace* GetDlMallocSpace() const { 613 return dlmalloc_space_; 614 } 615 616 space::RosAllocSpace* GetRosAllocSpace() const { 617 return rosalloc_space_; 618 } 619 620 // Return the corresponding rosalloc space. 621 space::RosAllocSpace* GetRosAllocSpace(gc::allocator::RosAlloc* rosalloc) const 622 SHARED_REQUIRES(Locks::mutator_lock_); 623 624 space::MallocSpace* GetNonMovingSpace() const { 625 return non_moving_space_; 626 } 627 628 space::LargeObjectSpace* GetLargeObjectsSpace() const { 629 return large_object_space_; 630 } 631 632 // Returns the free list space that may contain movable objects (the 633 // one that's not the non-moving space), either rosalloc_space_ or 634 // dlmalloc_space_. 635 space::MallocSpace* GetPrimaryFreeListSpace() { 636 if (kUseRosAlloc) { 637 DCHECK(rosalloc_space_ != nullptr); 638 // reinterpret_cast is necessary as the space class hierarchy 639 // isn't known (#included) yet here. 640 return reinterpret_cast<space::MallocSpace*>(rosalloc_space_); 641 } else { 642 DCHECK(dlmalloc_space_ != nullptr); 643 return reinterpret_cast<space::MallocSpace*>(dlmalloc_space_); 644 } 645 } 646 647 void DumpSpaces(std::ostream& stream) const SHARED_REQUIRES(Locks::mutator_lock_); 648 std::string DumpSpaces() const SHARED_REQUIRES(Locks::mutator_lock_); 649 650 // Dump object should only be used by the signal handler. 651 void DumpObject(std::ostream& stream, mirror::Object* obj) NO_THREAD_SAFETY_ANALYSIS; 652 // Safe version of pretty type of which check to make sure objects are heap addresses. 653 std::string SafeGetClassDescriptor(mirror::Class* klass) NO_THREAD_SAFETY_ANALYSIS; 654 std::string SafePrettyTypeOf(mirror::Object* obj) NO_THREAD_SAFETY_ANALYSIS; 655 656 // GC performance measuring 657 void DumpGcPerformanceInfo(std::ostream& os) 658 REQUIRES(!*gc_complete_lock_, !native_histogram_lock_); 659 void ResetGcPerformanceInfo() REQUIRES(!*gc_complete_lock_); 660 661 // Thread pool. 662 void CreateThreadPool(); 663 void DeleteThreadPool(); 664 ThreadPool* GetThreadPool() { 665 return thread_pool_.get(); 666 } 667 size_t GetParallelGCThreadCount() const { 668 return parallel_gc_threads_; 669 } 670 size_t GetConcGCThreadCount() const { 671 return conc_gc_threads_; 672 } 673 accounting::ModUnionTable* FindModUnionTableFromSpace(space::Space* space); 674 void AddModUnionTable(accounting::ModUnionTable* mod_union_table); 675 676 accounting::RememberedSet* FindRememberedSetFromSpace(space::Space* space); 677 void AddRememberedSet(accounting::RememberedSet* remembered_set); 678 // Also deletes the remebered set. 679 void RemoveRememberedSet(space::Space* space); 680 681 bool IsCompilingBoot() const; 682 bool HasBootImageSpace() const { 683 return !boot_image_spaces_.empty(); 684 } 685 686 ReferenceProcessor* GetReferenceProcessor() { 687 return reference_processor_.get(); 688 } 689 TaskProcessor* GetTaskProcessor() { 690 return task_processor_.get(); 691 } 692 693 bool HasZygoteSpace() const { 694 return zygote_space_ != nullptr; 695 } 696 697 collector::ConcurrentCopying* ConcurrentCopyingCollector() { 698 return concurrent_copying_collector_; 699 } 700 701 CollectorType CurrentCollectorType() { 702 return collector_type_; 703 } 704 705 bool IsGcConcurrentAndMoving() const { 706 if (IsGcConcurrent() && IsMovingGc(collector_type_)) { 707 // Assume no transition when a concurrent moving collector is used. 708 DCHECK_EQ(collector_type_, foreground_collector_type_); 709 DCHECK_EQ(foreground_collector_type_, background_collector_type_) 710 << "Assume no transition such that collector_type_ won't change"; 711 return true; 712 } 713 return false; 714 } 715 716 bool IsMovingGCDisabled(Thread* self) REQUIRES(!*gc_complete_lock_) { 717 MutexLock mu(self, *gc_complete_lock_); 718 return disable_moving_gc_count_ > 0; 719 } 720 721 // Request an asynchronous trim. 722 void RequestTrim(Thread* self) REQUIRES(!*pending_task_lock_); 723 724 // Request asynchronous GC. 725 void RequestConcurrentGC(Thread* self, bool force_full) REQUIRES(!*pending_task_lock_); 726 727 // Whether or not we may use a garbage collector, used so that we only create collectors we need. 728 bool MayUseCollector(CollectorType type) const; 729 730 // Used by tests to reduce timinig-dependent flakiness in OOME behavior. 731 void SetMinIntervalHomogeneousSpaceCompactionByOom(uint64_t interval) { 732 min_interval_homogeneous_space_compaction_by_oom_ = interval; 733 } 734 735 // Helpers for android.os.Debug.getRuntimeStat(). 736 uint64_t GetGcCount() const; 737 uint64_t GetGcTime() const; 738 uint64_t GetBlockingGcCount() const; 739 uint64_t GetBlockingGcTime() const; 740 void DumpGcCountRateHistogram(std::ostream& os) const REQUIRES(!*gc_complete_lock_); 741 void DumpBlockingGcCountRateHistogram(std::ostream& os) const REQUIRES(!*gc_complete_lock_); 742 743 // Allocation tracking support 744 // Callers to this function use double-checked locking to ensure safety on allocation_records_ 745 bool IsAllocTrackingEnabled() const { 746 return alloc_tracking_enabled_.LoadRelaxed(); 747 } 748 749 void SetAllocTrackingEnabled(bool enabled) REQUIRES(Locks::alloc_tracker_lock_) { 750 alloc_tracking_enabled_.StoreRelaxed(enabled); 751 } 752 753 AllocRecordObjectMap* GetAllocationRecords() const 754 REQUIRES(Locks::alloc_tracker_lock_) { 755 return allocation_records_.get(); 756 } 757 758 void SetAllocationRecords(AllocRecordObjectMap* records) 759 REQUIRES(Locks::alloc_tracker_lock_); 760 761 void VisitAllocationRecords(RootVisitor* visitor) const 762 SHARED_REQUIRES(Locks::mutator_lock_) 763 REQUIRES(!Locks::alloc_tracker_lock_); 764 765 void SweepAllocationRecords(IsMarkedVisitor* visitor) const 766 SHARED_REQUIRES(Locks::mutator_lock_) 767 REQUIRES(!Locks::alloc_tracker_lock_); 768 769 void DisallowNewAllocationRecords() const 770 SHARED_REQUIRES(Locks::mutator_lock_) 771 REQUIRES(!Locks::alloc_tracker_lock_); 772 773 void AllowNewAllocationRecords() const 774 SHARED_REQUIRES(Locks::mutator_lock_) 775 REQUIRES(!Locks::alloc_tracker_lock_); 776 777 void BroadcastForNewAllocationRecords() const 778 SHARED_REQUIRES(Locks::mutator_lock_) 779 REQUIRES(!Locks::alloc_tracker_lock_); 780 781 void DisableGCForShutdown() REQUIRES(!*gc_complete_lock_); 782 783 // Create a new alloc space and compact default alloc space to it. 784 HomogeneousSpaceCompactResult PerformHomogeneousSpaceCompact() REQUIRES(!*gc_complete_lock_); 785 bool SupportHomogeneousSpaceCompactAndCollectorTransitions() const; 786 787 private: 788 class ConcurrentGCTask; 789 class CollectorTransitionTask; 790 class HeapTrimTask; 791 792 // Compact source space to target space. Returns the collector used. 793 collector::GarbageCollector* Compact(space::ContinuousMemMapAllocSpace* target_space, 794 space::ContinuousMemMapAllocSpace* source_space, 795 GcCause gc_cause) 796 REQUIRES(Locks::mutator_lock_); 797 798 void LogGC(GcCause gc_cause, collector::GarbageCollector* collector); 799 void StartGC(Thread* self, GcCause cause, CollectorType collector_type) 800 REQUIRES(!*gc_complete_lock_); 801 void FinishGC(Thread* self, collector::GcType gc_type) REQUIRES(!*gc_complete_lock_); 802 803 // Create a mem map with a preferred base address. 804 static MemMap* MapAnonymousPreferredAddress(const char* name, uint8_t* request_begin, 805 size_t capacity, std::string* out_error_str); 806 807 bool SupportHSpaceCompaction() const { 808 // Returns true if we can do hspace compaction 809 return main_space_backup_ != nullptr; 810 } 811 812 static ALWAYS_INLINE bool AllocatorHasAllocationStack(AllocatorType allocator_type) { 813 return 814 allocator_type != kAllocatorTypeBumpPointer && 815 allocator_type != kAllocatorTypeTLAB && 816 allocator_type != kAllocatorTypeRegion && 817 allocator_type != kAllocatorTypeRegionTLAB; 818 } 819 static ALWAYS_INLINE bool AllocatorMayHaveConcurrentGC(AllocatorType allocator_type) { 820 return 821 allocator_type != kAllocatorTypeBumpPointer && 822 allocator_type != kAllocatorTypeTLAB; 823 } 824 static bool IsMovingGc(CollectorType collector_type) { 825 return 826 collector_type == kCollectorTypeSS || 827 collector_type == kCollectorTypeGSS || 828 collector_type == kCollectorTypeCC || 829 collector_type == kCollectorTypeMC || 830 collector_type == kCollectorTypeHomogeneousSpaceCompact; 831 } 832 bool ShouldAllocLargeObject(mirror::Class* c, size_t byte_count) const 833 SHARED_REQUIRES(Locks::mutator_lock_); 834 ALWAYS_INLINE void CheckConcurrentGC(Thread* self, 835 size_t new_num_bytes_allocated, 836 mirror::Object** obj) 837 SHARED_REQUIRES(Locks::mutator_lock_) 838 REQUIRES(!*pending_task_lock_, !*gc_complete_lock_); 839 840 accounting::ObjectStack* GetMarkStack() { 841 return mark_stack_.get(); 842 } 843 844 // We don't force this to be inlined since it is a slow path. 845 template <bool kInstrumented, typename PreFenceVisitor> 846 mirror::Object* AllocLargeObject(Thread* self, 847 mirror::Class** klass, 848 size_t byte_count, 849 const PreFenceVisitor& pre_fence_visitor) 850 SHARED_REQUIRES(Locks::mutator_lock_) 851 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !*backtrace_lock_); 852 853 // Handles Allocate()'s slow allocation path with GC involved after 854 // an initial allocation attempt failed. 855 mirror::Object* AllocateInternalWithGc(Thread* self, 856 AllocatorType allocator, 857 bool instrumented, 858 size_t num_bytes, 859 size_t* bytes_allocated, 860 size_t* usable_size, 861 size_t* bytes_tl_bulk_allocated, 862 mirror::Class** klass) 863 REQUIRES(!Locks::thread_suspend_count_lock_, !*gc_complete_lock_, !*pending_task_lock_) 864 SHARED_REQUIRES(Locks::mutator_lock_); 865 866 // Allocate into a specific space. 867 mirror::Object* AllocateInto(Thread* self, 868 space::AllocSpace* space, 869 mirror::Class* c, 870 size_t bytes) 871 SHARED_REQUIRES(Locks::mutator_lock_); 872 873 // Need to do this with mutators paused so that somebody doesn't accidentally allocate into the 874 // wrong space. 875 void SwapSemiSpaces() REQUIRES(Locks::mutator_lock_); 876 877 // Try to allocate a number of bytes, this function never does any GCs. Needs to be inlined so 878 // that the switch statement is constant optimized in the entrypoints. 879 template <const bool kInstrumented, const bool kGrow> 880 ALWAYS_INLINE mirror::Object* TryToAllocate(Thread* self, 881 AllocatorType allocator_type, 882 size_t alloc_size, 883 size_t* bytes_allocated, 884 size_t* usable_size, 885 size_t* bytes_tl_bulk_allocated) 886 SHARED_REQUIRES(Locks::mutator_lock_); 887 888 void ThrowOutOfMemoryError(Thread* self, size_t byte_count, AllocatorType allocator_type) 889 SHARED_REQUIRES(Locks::mutator_lock_); 890 891 template <bool kGrow> 892 ALWAYS_INLINE bool IsOutOfMemoryOnAllocation(AllocatorType allocator_type, size_t alloc_size); 893 894 // Returns true if the address passed in is within the address range of a continuous space. 895 bool IsValidContinuousSpaceObjectAddress(const mirror::Object* obj) const 896 SHARED_REQUIRES(Locks::mutator_lock_); 897 898 // Run the finalizers. If timeout is non zero, then we use the VMRuntime version. 899 void RunFinalization(JNIEnv* env, uint64_t timeout); 900 901 // Blocks the caller until the garbage collector becomes idle and returns the type of GC we 902 // waited for. 903 collector::GcType WaitForGcToCompleteLocked(GcCause cause, Thread* self) 904 REQUIRES(gc_complete_lock_); 905 906 void RequestCollectorTransition(CollectorType desired_collector_type, uint64_t delta_time) 907 REQUIRES(!*pending_task_lock_); 908 909 void RequestConcurrentGCAndSaveObject(Thread* self, bool force_full, mirror::Object** obj) 910 SHARED_REQUIRES(Locks::mutator_lock_) 911 REQUIRES(!*pending_task_lock_); 912 bool IsGCRequestPending() const; 913 914 // Sometimes CollectGarbageInternal decides to run a different Gc than you requested. Returns 915 // which type of Gc was actually ran. 916 collector::GcType CollectGarbageInternal(collector::GcType gc_plan, 917 GcCause gc_cause, 918 bool clear_soft_references) 919 REQUIRES(!*gc_complete_lock_, !Locks::heap_bitmap_lock_, !Locks::thread_suspend_count_lock_, 920 !*pending_task_lock_); 921 922 void PreGcVerification(collector::GarbageCollector* gc) 923 REQUIRES(!Locks::mutator_lock_, !*gc_complete_lock_); 924 void PreGcVerificationPaused(collector::GarbageCollector* gc) 925 REQUIRES(Locks::mutator_lock_, !*gc_complete_lock_); 926 void PrePauseRosAllocVerification(collector::GarbageCollector* gc) 927 REQUIRES(Locks::mutator_lock_); 928 void PreSweepingGcVerification(collector::GarbageCollector* gc) 929 REQUIRES(Locks::mutator_lock_, !Locks::heap_bitmap_lock_, !*gc_complete_lock_); 930 void PostGcVerification(collector::GarbageCollector* gc) 931 REQUIRES(!Locks::mutator_lock_, !*gc_complete_lock_); 932 void PostGcVerificationPaused(collector::GarbageCollector* gc) 933 REQUIRES(Locks::mutator_lock_, !*gc_complete_lock_); 934 935 // Update the watermark for the native allocated bytes based on the current number of native 936 // bytes allocated and the target utilization ratio. 937 void UpdateMaxNativeFootprint(); 938 939 // Find a collector based on GC type. 940 collector::GarbageCollector* FindCollectorByGcType(collector::GcType gc_type); 941 942 // Create the main free list malloc space, either a RosAlloc space or DlMalloc space. 943 void CreateMainMallocSpace(MemMap* mem_map, 944 size_t initial_size, 945 size_t growth_limit, 946 size_t capacity); 947 948 // Create a malloc space based on a mem map. Does not set the space as default. 949 space::MallocSpace* CreateMallocSpaceFromMemMap(MemMap* mem_map, 950 size_t initial_size, 951 size_t growth_limit, 952 size_t capacity, 953 const char* name, 954 bool can_move_objects); 955 956 // Given the current contents of the alloc space, increase the allowed heap footprint to match 957 // the target utilization ratio. This should only be called immediately after a full garbage 958 // collection. bytes_allocated_before_gc is used to measure bytes / second for the period which 959 // the GC was run. 960 void GrowForUtilization(collector::GarbageCollector* collector_ran, 961 uint64_t bytes_allocated_before_gc = 0); 962 963 size_t GetPercentFree(); 964 965 static void VerificationCallback(mirror::Object* obj, void* arg) 966 SHARED_REQUIRES(Locks::heap_bitmap_lock_); 967 968 // Swap the allocation stack with the live stack. 969 void SwapStacks() SHARED_REQUIRES(Locks::mutator_lock_); 970 971 // Clear cards and update the mod union table. When process_alloc_space_cards is true, 972 // if clear_alloc_space_cards is true, then we clear cards instead of ageing them. We do 973 // not process the alloc space if process_alloc_space_cards is false. 974 void ProcessCards(TimingLogger* timings, 975 bool use_rem_sets, 976 bool process_alloc_space_cards, 977 bool clear_alloc_space_cards) 978 SHARED_REQUIRES(Locks::mutator_lock_); 979 980 // Push an object onto the allocation stack. 981 void PushOnAllocationStack(Thread* self, mirror::Object** obj) 982 SHARED_REQUIRES(Locks::mutator_lock_) 983 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_); 984 void PushOnAllocationStackWithInternalGC(Thread* self, mirror::Object** obj) 985 SHARED_REQUIRES(Locks::mutator_lock_) 986 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_); 987 void PushOnThreadLocalAllocationStackWithInternalGC(Thread* thread, mirror::Object** obj) 988 SHARED_REQUIRES(Locks::mutator_lock_) 989 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_); 990 991 void ClearConcurrentGCRequest(); 992 void ClearPendingTrim(Thread* self) REQUIRES(!*pending_task_lock_); 993 void ClearPendingCollectorTransition(Thread* self) REQUIRES(!*pending_task_lock_); 994 995 // What kind of concurrency behavior is the runtime after? Currently true for concurrent mark 996 // sweep GC, false for other GC types. 997 bool IsGcConcurrent() const ALWAYS_INLINE { 998 return collector_type_ == kCollectorTypeCMS || collector_type_ == kCollectorTypeCC; 999 } 1000 1001 // Trim the managed and native spaces by releasing unused memory back to the OS. 1002 void TrimSpaces(Thread* self) REQUIRES(!*gc_complete_lock_); 1003 1004 // Trim 0 pages at the end of reference tables. 1005 void TrimIndirectReferenceTables(Thread* self); 1006 1007 void VisitObjectsInternal(ObjectCallback callback, void* arg) 1008 SHARED_REQUIRES(Locks::mutator_lock_) 1009 REQUIRES(!Locks::heap_bitmap_lock_, !*gc_complete_lock_); 1010 void VisitObjectsInternalRegionSpace(ObjectCallback callback, void* arg) 1011 REQUIRES(Locks::mutator_lock_, !Locks::heap_bitmap_lock_, !*gc_complete_lock_); 1012 1013 void UpdateGcCountRateHistograms() REQUIRES(gc_complete_lock_); 1014 1015 // GC stress mode attempts to do one GC per unique backtrace. 1016 void CheckGcStressMode(Thread* self, mirror::Object** obj) 1017 SHARED_REQUIRES(Locks::mutator_lock_) 1018 REQUIRES(!*gc_complete_lock_, !*pending_task_lock_, !*backtrace_lock_); 1019 1020 // All-known continuous spaces, where objects lie within fixed bounds. 1021 std::vector<space::ContinuousSpace*> continuous_spaces_ GUARDED_BY(Locks::mutator_lock_); 1022 1023 // All-known discontinuous spaces, where objects may be placed throughout virtual memory. 1024 std::vector<space::DiscontinuousSpace*> discontinuous_spaces_ GUARDED_BY(Locks::mutator_lock_); 1025 1026 // All-known alloc spaces, where objects may be or have been allocated. 1027 std::vector<space::AllocSpace*> alloc_spaces_; 1028 1029 // A space where non-movable objects are allocated, when compaction is enabled it contains 1030 // Classes, ArtMethods, ArtFields, and non moving objects. 1031 space::MallocSpace* non_moving_space_; 1032 1033 // Space which we use for the kAllocatorTypeROSAlloc. 1034 space::RosAllocSpace* rosalloc_space_; 1035 1036 // Space which we use for the kAllocatorTypeDlMalloc. 1037 space::DlMallocSpace* dlmalloc_space_; 1038 1039 // The main space is the space which the GC copies to and from on process state updates. This 1040 // space is typically either the dlmalloc_space_ or the rosalloc_space_. 1041 space::MallocSpace* main_space_; 1042 1043 // The large object space we are currently allocating into. 1044 space::LargeObjectSpace* large_object_space_; 1045 1046 // The card table, dirtied by the write barrier. 1047 std::unique_ptr<accounting::CardTable> card_table_; 1048 1049 std::unique_ptr<accounting::ReadBarrierTable> rb_table_; 1050 1051 // A mod-union table remembers all of the references from the it's space to other spaces. 1052 AllocationTrackingSafeMap<space::Space*, accounting::ModUnionTable*, kAllocatorTagHeap> 1053 mod_union_tables_; 1054 1055 // A remembered set remembers all of the references from the it's space to the target space. 1056 AllocationTrackingSafeMap<space::Space*, accounting::RememberedSet*, kAllocatorTagHeap> 1057 remembered_sets_; 1058 1059 // The current collector type. 1060 CollectorType collector_type_; 1061 // Which collector we use when the app is in the foreground. 1062 CollectorType foreground_collector_type_; 1063 // Which collector we will use when the app is notified of a transition to background. 1064 CollectorType background_collector_type_; 1065 // Desired collector type, heap trimming daemon transitions the heap if it is != collector_type_. 1066 CollectorType desired_collector_type_; 1067 1068 // Lock which guards pending tasks. 1069 Mutex* pending_task_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER; 1070 1071 // How many GC threads we may use for paused parts of garbage collection. 1072 const size_t parallel_gc_threads_; 1073 1074 // How many GC threads we may use for unpaused parts of garbage collection. 1075 const size_t conc_gc_threads_; 1076 1077 // Boolean for if we are in low memory mode. 1078 const bool low_memory_mode_; 1079 1080 // If we get a pause longer than long pause log threshold, then we print out the GC after it 1081 // finishes. 1082 const size_t long_pause_log_threshold_; 1083 1084 // If we get a GC longer than long GC log threshold, then we print out the GC after it finishes. 1085 const size_t long_gc_log_threshold_; 1086 1087 // If we ignore the max footprint it lets the heap grow until it hits the heap capacity, this is 1088 // useful for benchmarking since it reduces time spent in GC to a low %. 1089 const bool ignore_max_footprint_; 1090 1091 // Lock which guards zygote space creation. 1092 Mutex zygote_creation_lock_; 1093 1094 // Non-null iff we have a zygote space. Doesn't contain the large objects allocated before 1095 // zygote space creation. 1096 space::ZygoteSpace* zygote_space_; 1097 1098 // Minimum allocation size of large object. 1099 size_t large_object_threshold_; 1100 1101 // Guards access to the state of GC, associated conditional variable is used to signal when a GC 1102 // completes. 1103 Mutex* gc_complete_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER; 1104 std::unique_ptr<ConditionVariable> gc_complete_cond_ GUARDED_BY(gc_complete_lock_); 1105 1106 // Used to synchronize between JNI critical calls and the thread flip of the CC collector. 1107 Mutex* thread_flip_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER; 1108 std::unique_ptr<ConditionVariable> thread_flip_cond_ GUARDED_BY(thread_flip_lock_); 1109 // This counter keeps track of how many threads are currently in a JNI critical section. This is 1110 // incremented once per thread even with nested enters. 1111 size_t disable_thread_flip_count_ GUARDED_BY(thread_flip_lock_); 1112 bool thread_flip_running_ GUARDED_BY(thread_flip_lock_); 1113 1114 // Reference processor; 1115 std::unique_ptr<ReferenceProcessor> reference_processor_; 1116 1117 // Task processor, proxies heap trim requests to the daemon threads. 1118 std::unique_ptr<TaskProcessor> task_processor_; 1119 1120 // True while the garbage collector is running. 1121 volatile CollectorType collector_type_running_ GUARDED_BY(gc_complete_lock_); 1122 1123 // Last Gc type we ran. Used by WaitForConcurrentGc to know which Gc was waited on. 1124 volatile collector::GcType last_gc_type_ GUARDED_BY(gc_complete_lock_); 1125 collector::GcType next_gc_type_; 1126 1127 // Maximum size that the heap can reach. 1128 size_t capacity_; 1129 1130 // The size the heap is limited to. This is initially smaller than capacity, but for largeHeap 1131 // programs it is "cleared" making it the same as capacity. 1132 size_t growth_limit_; 1133 1134 // When the number of bytes allocated exceeds the footprint TryAllocate returns null indicating 1135 // a GC should be triggered. 1136 size_t max_allowed_footprint_; 1137 1138 // The watermark at which a concurrent GC is requested by registerNativeAllocation. 1139 size_t native_footprint_gc_watermark_; 1140 1141 // Whether or not we need to run finalizers in the next native allocation. 1142 bool native_need_to_run_finalization_; 1143 1144 // When num_bytes_allocated_ exceeds this amount then a concurrent GC should be requested so that 1145 // it completes ahead of an allocation failing. 1146 size_t concurrent_start_bytes_; 1147 1148 // Since the heap was created, how many bytes have been freed. 1149 uint64_t total_bytes_freed_ever_; 1150 1151 // Since the heap was created, how many objects have been freed. 1152 uint64_t total_objects_freed_ever_; 1153 1154 // Number of bytes allocated. Adjusted after each allocation and free. 1155 Atomic<size_t> num_bytes_allocated_; 1156 1157 // Bytes which are allocated and managed by native code but still need to be accounted for. 1158 Atomic<size_t> native_bytes_allocated_; 1159 1160 // Native allocation stats. 1161 Mutex native_histogram_lock_; 1162 Histogram<uint64_t> native_allocation_histogram_; 1163 Histogram<uint64_t> native_free_histogram_; 1164 1165 // Number of bytes freed by thread local buffer revokes. This will 1166 // cancel out the ahead-of-time bulk counting of bytes allocated in 1167 // rosalloc thread-local buffers. It is temporarily accumulated 1168 // here to be subtracted from num_bytes_allocated_ later at the next 1169 // GC. 1170 Atomic<size_t> num_bytes_freed_revoke_; 1171 1172 // Info related to the current or previous GC iteration. 1173 collector::Iteration current_gc_iteration_; 1174 1175 // Heap verification flags. 1176 const bool verify_missing_card_marks_; 1177 const bool verify_system_weaks_; 1178 const bool verify_pre_gc_heap_; 1179 const bool verify_pre_sweeping_heap_; 1180 const bool verify_post_gc_heap_; 1181 const bool verify_mod_union_table_; 1182 bool verify_pre_gc_rosalloc_; 1183 bool verify_pre_sweeping_rosalloc_; 1184 bool verify_post_gc_rosalloc_; 1185 const bool gc_stress_mode_; 1186 1187 // RAII that temporarily disables the rosalloc verification during 1188 // the zygote fork. 1189 class ScopedDisableRosAllocVerification { 1190 private: 1191 Heap* const heap_; 1192 const bool orig_verify_pre_gc_; 1193 const bool orig_verify_pre_sweeping_; 1194 const bool orig_verify_post_gc_; 1195 1196 public: 1197 explicit ScopedDisableRosAllocVerification(Heap* heap) 1198 : heap_(heap), 1199 orig_verify_pre_gc_(heap_->verify_pre_gc_rosalloc_), 1200 orig_verify_pre_sweeping_(heap_->verify_pre_sweeping_rosalloc_), 1201 orig_verify_post_gc_(heap_->verify_post_gc_rosalloc_) { 1202 heap_->verify_pre_gc_rosalloc_ = false; 1203 heap_->verify_pre_sweeping_rosalloc_ = false; 1204 heap_->verify_post_gc_rosalloc_ = false; 1205 } 1206 ~ScopedDisableRosAllocVerification() { 1207 heap_->verify_pre_gc_rosalloc_ = orig_verify_pre_gc_; 1208 heap_->verify_pre_sweeping_rosalloc_ = orig_verify_pre_sweeping_; 1209 heap_->verify_post_gc_rosalloc_ = orig_verify_post_gc_; 1210 } 1211 }; 1212 1213 // Parallel GC data structures. 1214 std::unique_ptr<ThreadPool> thread_pool_; 1215 1216 // Estimated allocation rate (bytes / second). Computed between the time of the last GC cycle 1217 // and the start of the current one. 1218 uint64_t allocation_rate_; 1219 1220 // For a GC cycle, a bitmap that is set corresponding to the 1221 std::unique_ptr<accounting::HeapBitmap> live_bitmap_ GUARDED_BY(Locks::heap_bitmap_lock_); 1222 std::unique_ptr<accounting::HeapBitmap> mark_bitmap_ GUARDED_BY(Locks::heap_bitmap_lock_); 1223 1224 // Mark stack that we reuse to avoid re-allocating the mark stack. 1225 std::unique_ptr<accounting::ObjectStack> mark_stack_; 1226 1227 // Allocation stack, new allocations go here so that we can do sticky mark bits. This enables us 1228 // to use the live bitmap as the old mark bitmap. 1229 const size_t max_allocation_stack_size_; 1230 std::unique_ptr<accounting::ObjectStack> allocation_stack_; 1231 1232 // Second allocation stack so that we can process allocation with the heap unlocked. 1233 std::unique_ptr<accounting::ObjectStack> live_stack_; 1234 1235 // Allocator type. 1236 AllocatorType current_allocator_; 1237 const AllocatorType current_non_moving_allocator_; 1238 1239 // Which GCs we run in order when we an allocation fails. 1240 std::vector<collector::GcType> gc_plan_; 1241 1242 // Bump pointer spaces. 1243 space::BumpPointerSpace* bump_pointer_space_; 1244 // Temp space is the space which the semispace collector copies to. 1245 space::BumpPointerSpace* temp_space_; 1246 1247 space::RegionSpace* region_space_; 1248 1249 // Minimum free guarantees that you always have at least min_free_ free bytes after growing for 1250 // utilization, regardless of target utilization ratio. 1251 size_t min_free_; 1252 1253 // The ideal maximum free size, when we grow the heap for utilization. 1254 size_t max_free_; 1255 1256 // Target ideal heap utilization ratio 1257 double target_utilization_; 1258 1259 // How much more we grow the heap when we are a foreground app instead of background. 1260 double foreground_heap_growth_multiplier_; 1261 1262 // Total time which mutators are paused or waiting for GC to complete. 1263 uint64_t total_wait_time_; 1264 1265 // The current state of heap verification, may be enabled or disabled. 1266 VerifyObjectMode verify_object_mode_; 1267 1268 // Compacting GC disable count, prevents compacting GC from running iff > 0. 1269 size_t disable_moving_gc_count_ GUARDED_BY(gc_complete_lock_); 1270 1271 std::vector<collector::GarbageCollector*> garbage_collectors_; 1272 collector::SemiSpace* semi_space_collector_; 1273 collector::MarkCompact* mark_compact_collector_; 1274 collector::ConcurrentCopying* concurrent_copying_collector_; 1275 1276 const bool is_running_on_memory_tool_; 1277 const bool use_tlab_; 1278 1279 // Pointer to the space which becomes the new main space when we do homogeneous space compaction. 1280 // Use unique_ptr since the space is only added during the homogeneous compaction phase. 1281 std::unique_ptr<space::MallocSpace> main_space_backup_; 1282 1283 // Minimal interval allowed between two homogeneous space compactions caused by OOM. 1284 uint64_t min_interval_homogeneous_space_compaction_by_oom_; 1285 1286 // Times of the last homogeneous space compaction caused by OOM. 1287 uint64_t last_time_homogeneous_space_compaction_by_oom_; 1288 1289 // Saved OOMs by homogeneous space compaction. 1290 Atomic<size_t> count_delayed_oom_; 1291 1292 // Count for requested homogeneous space compaction. 1293 Atomic<size_t> count_requested_homogeneous_space_compaction_; 1294 1295 // Count for ignored homogeneous space compaction. 1296 Atomic<size_t> count_ignored_homogeneous_space_compaction_; 1297 1298 // Count for performed homogeneous space compaction. 1299 Atomic<size_t> count_performed_homogeneous_space_compaction_; 1300 1301 // Whether or not a concurrent GC is pending. 1302 Atomic<bool> concurrent_gc_pending_; 1303 1304 // Active tasks which we can modify (change target time, desired collector type, etc..). 1305 CollectorTransitionTask* pending_collector_transition_ GUARDED_BY(pending_task_lock_); 1306 HeapTrimTask* pending_heap_trim_ GUARDED_BY(pending_task_lock_); 1307 1308 // Whether or not we use homogeneous space compaction to avoid OOM errors. 1309 bool use_homogeneous_space_compaction_for_oom_; 1310 1311 // True if the currently running collection has made some thread wait. 1312 bool running_collection_is_blocking_ GUARDED_BY(gc_complete_lock_); 1313 // The number of blocking GC runs. 1314 uint64_t blocking_gc_count_; 1315 // The total duration of blocking GC runs. 1316 uint64_t blocking_gc_time_; 1317 // The duration of the window for the GC count rate histograms. 1318 static constexpr uint64_t kGcCountRateHistogramWindowDuration = MsToNs(10 * 1000); // 10s. 1319 // The last time when the GC count rate histograms were updated. 1320 // This is rounded by kGcCountRateHistogramWindowDuration (a multiple of 10s). 1321 uint64_t last_update_time_gc_count_rate_histograms_; 1322 // The running count of GC runs in the last window. 1323 uint64_t gc_count_last_window_; 1324 // The running count of blocking GC runs in the last window. 1325 uint64_t blocking_gc_count_last_window_; 1326 // The maximum number of buckets in the GC count rate histograms. 1327 static constexpr size_t kGcCountRateMaxBucketCount = 200; 1328 // The histogram of the number of GC invocations per window duration. 1329 Histogram<uint64_t> gc_count_rate_histogram_ GUARDED_BY(gc_complete_lock_); 1330 // The histogram of the number of blocking GC invocations per window duration. 1331 Histogram<uint64_t> blocking_gc_count_rate_histogram_ GUARDED_BY(gc_complete_lock_); 1332 1333 // Allocation tracking support 1334 Atomic<bool> alloc_tracking_enabled_; 1335 std::unique_ptr<AllocRecordObjectMap> allocation_records_; 1336 1337 // GC stress related data structures. 1338 Mutex* backtrace_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER; 1339 // Debugging variables, seen backtraces vs unique backtraces. 1340 Atomic<uint64_t> seen_backtrace_count_; 1341 Atomic<uint64_t> unique_backtrace_count_; 1342 // Stack trace hashes that we already saw, 1343 std::unordered_set<uint64_t> seen_backtraces_ GUARDED_BY(backtrace_lock_); 1344 1345 // We disable GC when we are shutting down the runtime in case there are daemon threads still 1346 // allocating. 1347 bool gc_disabled_for_shutdown_ GUARDED_BY(gc_complete_lock_); 1348 1349 // Boot image spaces. 1350 std::vector<space::ImageSpace*> boot_image_spaces_; 1351 1352 friend class CollectorTransitionTask; 1353 friend class collector::GarbageCollector; 1354 friend class collector::MarkCompact; 1355 friend class collector::ConcurrentCopying; 1356 friend class collector::MarkSweep; 1357 friend class collector::SemiSpace; 1358 friend class ReferenceQueue; 1359 friend class ScopedGCCriticalSection; 1360 friend class VerifyReferenceCardVisitor; 1361 friend class VerifyReferenceVisitor; 1362 friend class VerifyObjectVisitor; 1363 1364 DISALLOW_IMPLICIT_CONSTRUCTORS(Heap); 1365 }; 1366 1367 } // namespace gc 1368 } // namespace art 1369 1370 #endif // ART_RUNTIME_GC_HEAP_H_ 1371
