mutex.h revision 2435a43f6c851c23922d8508fb17c6079248201c
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#ifndef ART_RUNTIME_BASE_MUTEX_H_ 18#define ART_RUNTIME_BASE_MUTEX_H_ 19 20#include <pthread.h> 21#include <stdint.h> 22 23#include <iosfwd> 24#include <string> 25 26#include "atomic.h" 27#include "base/logging.h" 28#include "base/macros.h" 29#include "globals.h" 30 31#if defined(__APPLE__) 32#define ART_USE_FUTEXES 0 33#else 34#define ART_USE_FUTEXES 1 35#endif 36 37// Currently Darwin doesn't support locks with timeouts. 38#if !defined(__APPLE__) 39#define HAVE_TIMED_RWLOCK 1 40#else 41#define HAVE_TIMED_RWLOCK 0 42#endif 43 44namespace art { 45 46class LOCKABLE ReaderWriterMutex; 47class ScopedContentionRecorder; 48class Thread; 49 50// LockLevel is used to impose a lock hierarchy [1] where acquisition of a Mutex at a higher or 51// equal level to a lock a thread holds is invalid. The lock hierarchy achieves a cycle free 52// partial ordering and thereby cause deadlock situations to fail checks. 53// 54// [1] http://www.drdobbs.com/parallel/use-lock-hierarchies-to-avoid-deadlock/204801163 55enum LockLevel { 56 kLoggingLock = 0, 57 kMemMapsLock, 58 kSwapMutexesLock, 59 kUnexpectedSignalLock, 60 kThreadSuspendCountLock, 61 kAbortLock, 62 kJdwpSocketLock, 63 kRegionSpaceRegionLock, 64 kReferenceQueueSoftReferencesLock, 65 kReferenceQueuePhantomReferencesLock, 66 kReferenceQueueFinalizerReferencesLock, 67 kReferenceQueueWeakReferencesLock, 68 kReferenceQueueClearedReferencesLock, 69 kReferenceProcessorLock, 70 kJitCodeCacheLock, 71 kRosAllocGlobalLock, 72 kRosAllocBracketLock, 73 kRosAllocBulkFreeLock, 74 kAllocSpaceLock, 75 kBumpPointerSpaceBlockLock, 76 kDexFileMethodInlinerLock, 77 kDexFileToMethodInlinerMapLock, 78 kMarkSweepMarkStackLock, 79 kTransactionLogLock, 80 kInternTableLock, 81 kOatFileSecondaryLookupLock, 82 kDefaultMutexLevel, 83 kMarkSweepLargeObjectLock, 84 kPinTableLock, 85 kJdwpObjectRegistryLock, 86 kModifyLdtLock, 87 kAllocatedThreadIdsLock, 88 kMonitorPoolLock, 89 kMethodVerifiersLock, 90 kClassLinkerClassesLock, 91 kBreakpointLock, 92 kMonitorLock, 93 kMonitorListLock, 94 kJniLoadLibraryLock, 95 kThreadListLock, 96 kBreakpointInvokeLock, 97 kAllocTrackerLock, 98 kDeoptimizationLock, 99 kProfilerLock, 100 kJdwpEventListLock, 101 kJdwpAttachLock, 102 kJdwpStartLock, 103 kRuntimeShutdownLock, 104 kTraceLock, 105 kHeapBitmapLock, 106 kMutatorLock, 107 kInstrumentEntrypointsLock, 108 kZygoteCreationLock, 109 110 kLockLevelCount // Must come last. 111}; 112std::ostream& operator<<(std::ostream& os, const LockLevel& rhs); 113 114const bool kDebugLocking = kIsDebugBuild; 115 116// Record Log contention information, dumpable via SIGQUIT. 117#ifdef ART_USE_FUTEXES 118// To enable lock contention logging, set this to true. 119const bool kLogLockContentions = false; 120#else 121// Keep this false as lock contention logging is supported only with 122// futex. 123const bool kLogLockContentions = false; 124#endif 125const size_t kContentionLogSize = 4; 126const size_t kContentionLogDataSize = kLogLockContentions ? 1 : 0; 127const size_t kAllMutexDataSize = kLogLockContentions ? 1 : 0; 128 129// Base class for all Mutex implementations 130class BaseMutex { 131 public: 132 const char* GetName() const { 133 return name_; 134 } 135 136 virtual bool IsMutex() const { return false; } 137 virtual bool IsReaderWriterMutex() const { return false; } 138 139 virtual void Dump(std::ostream& os) const = 0; 140 141 static void DumpAll(std::ostream& os); 142 143 protected: 144 friend class ConditionVariable; 145 146 BaseMutex(const char* name, LockLevel level); 147 virtual ~BaseMutex(); 148 void RegisterAsLocked(Thread* self); 149 void RegisterAsUnlocked(Thread* self); 150 void CheckSafeToWait(Thread* self); 151 152 friend class ScopedContentionRecorder; 153 154 void RecordContention(uint64_t blocked_tid, uint64_t owner_tid, uint64_t nano_time_blocked); 155 void DumpContention(std::ostream& os) const; 156 157 const LockLevel level_; // Support for lock hierarchy. 158 const char* const name_; 159 160 // A log entry that records contention but makes no guarantee that either tid will be held live. 161 struct ContentionLogEntry { 162 ContentionLogEntry() : blocked_tid(0), owner_tid(0) {} 163 uint64_t blocked_tid; 164 uint64_t owner_tid; 165 AtomicInteger count; 166 }; 167 struct ContentionLogData { 168 ContentionLogEntry contention_log[kContentionLogSize]; 169 // The next entry in the contention log to be updated. Value ranges from 0 to 170 // kContentionLogSize - 1. 171 AtomicInteger cur_content_log_entry; 172 // Number of times the Mutex has been contended. 173 AtomicInteger contention_count; 174 // Sum of time waited by all contenders in ns. 175 Atomic<uint64_t> wait_time; 176 void AddToWaitTime(uint64_t value); 177 ContentionLogData() : wait_time(0) {} 178 }; 179 ContentionLogData contention_log_data_[kContentionLogDataSize]; 180 181 public: 182 bool HasEverContended() const { 183 if (kLogLockContentions) { 184 return contention_log_data_->contention_count.LoadSequentiallyConsistent() > 0; 185 } 186 return false; 187 } 188}; 189 190// A Mutex is used to achieve mutual exclusion between threads. A Mutex can be used to gain 191// exclusive access to what it guards. A Mutex can be in one of two states: 192// - Free - not owned by any thread, 193// - Exclusive - owned by a single thread. 194// 195// The effect of locking and unlocking operations on the state is: 196// State | ExclusiveLock | ExclusiveUnlock 197// ------------------------------------------- 198// Free | Exclusive | error 199// Exclusive | Block* | Free 200// * Mutex is not reentrant and so an attempt to ExclusiveLock on the same thread will result in 201// an error. Being non-reentrant simplifies Waiting on ConditionVariables. 202std::ostream& operator<<(std::ostream& os, const Mutex& mu); 203class LOCKABLE Mutex : public BaseMutex { 204 public: 205 explicit Mutex(const char* name, LockLevel level = kDefaultMutexLevel, bool recursive = false); 206 ~Mutex(); 207 208 virtual bool IsMutex() const { return true; } 209 210 // Block until mutex is free then acquire exclusive access. 211 void ExclusiveLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION(); 212 void Lock(Thread* self) EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(self); } 213 214 // Returns true if acquires exclusive access, false otherwise. 215 bool ExclusiveTryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true); 216 bool TryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true) { return ExclusiveTryLock(self); } 217 218 // Release exclusive access. 219 void ExclusiveUnlock(Thread* self) UNLOCK_FUNCTION(); 220 void Unlock(Thread* self) UNLOCK_FUNCTION() { ExclusiveUnlock(self); } 221 222 // Is the current thread the exclusive holder of the Mutex. 223 bool IsExclusiveHeld(const Thread* self) const; 224 225 // Assert that the Mutex is exclusively held by the current thread. 226 void AssertExclusiveHeld(const Thread* self) { 227 if (kDebugLocking && (gAborting == 0)) { 228 CHECK(IsExclusiveHeld(self)) << *this; 229 } 230 } 231 void AssertHeld(const Thread* self) { AssertExclusiveHeld(self); } 232 233 // Assert that the Mutex is not held by the current thread. 234 void AssertNotHeldExclusive(const Thread* self) { 235 if (kDebugLocking && (gAborting == 0)) { 236 CHECK(!IsExclusiveHeld(self)) << *this; 237 } 238 } 239 void AssertNotHeld(const Thread* self) { AssertNotHeldExclusive(self); } 240 241 // Id associated with exclusive owner. No memory ordering semantics if called from a thread other 242 // than the owner. 243 uint64_t GetExclusiveOwnerTid() const; 244 245 // Returns how many times this Mutex has been locked, it is better to use AssertHeld/NotHeld. 246 unsigned int GetDepth() const { 247 return recursion_count_; 248 } 249 250 virtual void Dump(std::ostream& os) const; 251 252 private: 253#if ART_USE_FUTEXES 254 // 0 is unheld, 1 is held. 255 AtomicInteger state_; 256 // Exclusive owner. 257 volatile uint64_t exclusive_owner_; 258 // Number of waiting contenders. 259 AtomicInteger num_contenders_; 260#else 261 pthread_mutex_t mutex_; 262 volatile uint64_t exclusive_owner_; // Guarded by mutex_. 263#endif 264 const bool recursive_; // Can the lock be recursively held? 265 unsigned int recursion_count_; 266 friend class ConditionVariable; 267 DISALLOW_COPY_AND_ASSIGN(Mutex); 268}; 269 270// A ReaderWriterMutex is used to achieve mutual exclusion between threads, similar to a Mutex. 271// Unlike a Mutex a ReaderWriterMutex can be used to gain exclusive (writer) or shared (reader) 272// access to what it guards. A flaw in relation to a Mutex is that it cannot be used with a 273// condition variable. A ReaderWriterMutex can be in one of three states: 274// - Free - not owned by any thread, 275// - Exclusive - owned by a single thread, 276// - Shared(n) - shared amongst n threads. 277// 278// The effect of locking and unlocking operations on the state is: 279// 280// State | ExclusiveLock | ExclusiveUnlock | SharedLock | SharedUnlock 281// ---------------------------------------------------------------------------- 282// Free | Exclusive | error | SharedLock(1) | error 283// Exclusive | Block | Free | Block | error 284// Shared(n) | Block | error | SharedLock(n+1)* | Shared(n-1) or Free 285// * for large values of n the SharedLock may block. 286std::ostream& operator<<(std::ostream& os, const ReaderWriterMutex& mu); 287class LOCKABLE ReaderWriterMutex : public BaseMutex { 288 public: 289 explicit ReaderWriterMutex(const char* name, LockLevel level = kDefaultMutexLevel); 290 ~ReaderWriterMutex(); 291 292 virtual bool IsReaderWriterMutex() const { return true; } 293 294 // Block until ReaderWriterMutex is free then acquire exclusive access. 295 void ExclusiveLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION(); 296 void WriterLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(self); } 297 298 // Release exclusive access. 299 void ExclusiveUnlock(Thread* self) UNLOCK_FUNCTION(); 300 void WriterUnlock(Thread* self) UNLOCK_FUNCTION() { ExclusiveUnlock(self); } 301 302 // Block until ReaderWriterMutex is free and acquire exclusive access. Returns true on success 303 // or false if timeout is reached. 304#if HAVE_TIMED_RWLOCK 305 bool ExclusiveLockWithTimeout(Thread* self, int64_t ms, int32_t ns) 306 EXCLUSIVE_TRYLOCK_FUNCTION(true); 307#endif 308 309 // Block until ReaderWriterMutex is shared or free then acquire a share on the access. 310 void SharedLock(Thread* self) SHARED_LOCK_FUNCTION() ALWAYS_INLINE; 311 void ReaderLock(Thread* self) SHARED_LOCK_FUNCTION() { SharedLock(self); } 312 313 // Try to acquire share of ReaderWriterMutex. 314 bool SharedTryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true); 315 316 // Release a share of the access. 317 void SharedUnlock(Thread* self) UNLOCK_FUNCTION() ALWAYS_INLINE; 318 void ReaderUnlock(Thread* self) UNLOCK_FUNCTION() { SharedUnlock(self); } 319 320 // Is the current thread the exclusive holder of the ReaderWriterMutex. 321 bool IsExclusiveHeld(const Thread* self) const; 322 323 // Assert the current thread has exclusive access to the ReaderWriterMutex. 324 void AssertExclusiveHeld(const Thread* self) { 325 if (kDebugLocking && (gAborting == 0)) { 326 CHECK(IsExclusiveHeld(self)) << *this; 327 } 328 } 329 void AssertWriterHeld(const Thread* self) { AssertExclusiveHeld(self); } 330 331 // Assert the current thread doesn't have exclusive access to the ReaderWriterMutex. 332 void AssertNotExclusiveHeld(const Thread* self) { 333 if (kDebugLocking && (gAborting == 0)) { 334 CHECK(!IsExclusiveHeld(self)) << *this; 335 } 336 } 337 void AssertNotWriterHeld(const Thread* self) { AssertNotExclusiveHeld(self); } 338 339 // Is the current thread a shared holder of the ReaderWriterMutex. 340 bool IsSharedHeld(const Thread* self) const; 341 342 // Assert the current thread has shared access to the ReaderWriterMutex. 343 void AssertSharedHeld(const Thread* self) { 344 if (kDebugLocking && (gAborting == 0)) { 345 // TODO: we can only assert this well when self != NULL. 346 CHECK(IsSharedHeld(self) || self == NULL) << *this; 347 } 348 } 349 void AssertReaderHeld(const Thread* self) { AssertSharedHeld(self); } 350 351 // Assert the current thread doesn't hold this ReaderWriterMutex either in shared or exclusive 352 // mode. 353 void AssertNotHeld(const Thread* self) { 354 if (kDebugLocking && (gAborting == 0)) { 355 CHECK(!IsSharedHeld(self)) << *this; 356 } 357 } 358 359 // Id associated with exclusive owner. No memory ordering semantics if called from a thread other 360 // than the owner. 361 uint64_t GetExclusiveOwnerTid() const; 362 363 virtual void Dump(std::ostream& os) const; 364 365 private: 366#if ART_USE_FUTEXES 367 // Out-of-inline path for handling contention for a SharedLock. 368 void HandleSharedLockContention(Thread* self, int32_t cur_state); 369 370 // -1 implies held exclusive, +ve shared held by state_ many owners. 371 AtomicInteger state_; 372 // Exclusive owner. Modification guarded by this mutex. 373 volatile uint64_t exclusive_owner_; 374 // Number of contenders waiting for a reader share. 375 AtomicInteger num_pending_readers_; 376 // Number of contenders waiting to be the writer. 377 AtomicInteger num_pending_writers_; 378#else 379 pthread_rwlock_t rwlock_; 380 volatile uint64_t exclusive_owner_; // Guarded by rwlock_. 381#endif 382 DISALLOW_COPY_AND_ASSIGN(ReaderWriterMutex); 383}; 384 385// ConditionVariables allow threads to queue and sleep. Threads may then be resumed individually 386// (Signal) or all at once (Broadcast). 387class ConditionVariable { 388 public: 389 explicit ConditionVariable(const char* name, Mutex& mutex); 390 ~ConditionVariable(); 391 392 void Broadcast(Thread* self); 393 void Signal(Thread* self); 394 // TODO: No thread safety analysis on Wait and TimedWait as they call mutex operations via their 395 // pointer copy, thereby defeating annotalysis. 396 void Wait(Thread* self) NO_THREAD_SAFETY_ANALYSIS; 397 bool TimedWait(Thread* self, int64_t ms, int32_t ns) NO_THREAD_SAFETY_ANALYSIS; 398 // Variant of Wait that should be used with caution. Doesn't validate that no mutexes are held 399 // when waiting. 400 // TODO: remove this. 401 void WaitHoldingLocks(Thread* self) NO_THREAD_SAFETY_ANALYSIS; 402 403 private: 404 const char* const name_; 405 // The Mutex being used by waiters. It is an error to mix condition variables between different 406 // Mutexes. 407 Mutex& guard_; 408#if ART_USE_FUTEXES 409 // A counter that is modified by signals and broadcasts. This ensures that when a waiter gives up 410 // their Mutex and another thread takes it and signals, the waiting thread observes that sequence_ 411 // changed and doesn't enter the wait. Modified while holding guard_, but is read by futex wait 412 // without guard_ held. 413 AtomicInteger sequence_; 414 // Number of threads that have come into to wait, not the length of the waiters on the futex as 415 // waiters may have been requeued onto guard_. Guarded by guard_. 416 volatile int32_t num_waiters_; 417#else 418 pthread_cond_t cond_; 419#endif 420 DISALLOW_COPY_AND_ASSIGN(ConditionVariable); 421}; 422 423// Scoped locker/unlocker for a regular Mutex that acquires mu upon construction and releases it 424// upon destruction. 425class SCOPED_LOCKABLE MutexLock { 426 public: 427 explicit MutexLock(Thread* self, Mutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : self_(self), mu_(mu) { 428 mu_.ExclusiveLock(self_); 429 } 430 431 ~MutexLock() UNLOCK_FUNCTION() { 432 mu_.ExclusiveUnlock(self_); 433 } 434 435 private: 436 Thread* const self_; 437 Mutex& mu_; 438 DISALLOW_COPY_AND_ASSIGN(MutexLock); 439}; 440// Catch bug where variable name is omitted. "MutexLock (lock);" instead of "MutexLock mu(lock)". 441#define MutexLock(x) static_assert(0, "MutexLock declaration missing variable name") 442 443// Scoped locker/unlocker for a ReaderWriterMutex that acquires read access to mu upon 444// construction and releases it upon destruction. 445class SCOPED_LOCKABLE ReaderMutexLock { 446 public: 447 explicit ReaderMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : 448 self_(self), mu_(mu) { 449 mu_.SharedLock(self_); 450 } 451 452 ~ReaderMutexLock() UNLOCK_FUNCTION() { 453 mu_.SharedUnlock(self_); 454 } 455 456 private: 457 Thread* const self_; 458 ReaderWriterMutex& mu_; 459 DISALLOW_COPY_AND_ASSIGN(ReaderMutexLock); 460}; 461// Catch bug where variable name is omitted. "ReaderMutexLock (lock);" instead of 462// "ReaderMutexLock mu(lock)". 463#define ReaderMutexLock(x) static_assert(0, "ReaderMutexLock declaration missing variable name") 464 465// Scoped locker/unlocker for a ReaderWriterMutex that acquires write access to mu upon 466// construction and releases it upon destruction. 467class SCOPED_LOCKABLE WriterMutexLock { 468 public: 469 explicit WriterMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : 470 self_(self), mu_(mu) { 471 mu_.ExclusiveLock(self_); 472 } 473 474 ~WriterMutexLock() UNLOCK_FUNCTION() { 475 mu_.ExclusiveUnlock(self_); 476 } 477 478 private: 479 Thread* const self_; 480 ReaderWriterMutex& mu_; 481 DISALLOW_COPY_AND_ASSIGN(WriterMutexLock); 482}; 483// Catch bug where variable name is omitted. "WriterMutexLock (lock);" instead of 484// "WriterMutexLock mu(lock)". 485#define WriterMutexLock(x) static_assert(0, "WriterMutexLock declaration missing variable name") 486 487// Global mutexes corresponding to the levels above. 488class Locks { 489 public: 490 static void Init(); 491 static void InitConditions() NO_THREAD_SAFETY_ANALYSIS; // Condition variables. 492 // Guards allocation entrypoint instrumenting. 493 static Mutex* instrument_entrypoints_lock_; 494 495 // The mutator_lock_ is used to allow mutators to execute in a shared (reader) mode or to block 496 // mutators by having an exclusive (writer) owner. In normal execution each mutator thread holds 497 // a share on the mutator_lock_. The garbage collector may also execute with shared access but 498 // at times requires exclusive access to the heap (not to be confused with the heap meta-data 499 // guarded by the heap_lock_ below). When the garbage collector requires exclusive access it asks 500 // the mutators to suspend themselves which also involves usage of the thread_suspend_count_lock_ 501 // to cover weaknesses in using ReaderWriterMutexes with ConditionVariables. We use a condition 502 // variable to wait upon in the suspension logic as releasing and then re-acquiring a share on 503 // the mutator lock doesn't necessarily allow the exclusive user (e.g the garbage collector) 504 // chance to acquire the lock. 505 // 506 // Thread suspension: 507 // Shared users | Exclusive user 508 // (holding mutator lock and in kRunnable state) | .. running .. 509 // .. running .. | Request thread suspension by: 510 // .. running .. | - acquiring thread_suspend_count_lock_ 511 // .. running .. | - incrementing Thread::suspend_count_ on 512 // .. running .. | all mutator threads 513 // .. running .. | - releasing thread_suspend_count_lock_ 514 // .. running .. | Block trying to acquire exclusive mutator lock 515 // Poll Thread::suspend_count_ and enter full | .. blocked .. 516 // suspend code. | .. blocked .. 517 // Change state to kSuspended | .. blocked .. 518 // x: Release share on mutator_lock_ | Carry out exclusive access 519 // Acquire thread_suspend_count_lock_ | .. exclusive .. 520 // while Thread::suspend_count_ > 0 | .. exclusive .. 521 // - wait on Thread::resume_cond_ | .. exclusive .. 522 // (releases thread_suspend_count_lock_) | .. exclusive .. 523 // .. waiting .. | Release mutator_lock_ 524 // .. waiting .. | Request thread resumption by: 525 // .. waiting .. | - acquiring thread_suspend_count_lock_ 526 // .. waiting .. | - decrementing Thread::suspend_count_ on 527 // .. waiting .. | all mutator threads 528 // .. waiting .. | - notifying on Thread::resume_cond_ 529 // - re-acquire thread_suspend_count_lock_ | - releasing thread_suspend_count_lock_ 530 // Release thread_suspend_count_lock_ | .. running .. 531 // Acquire share on mutator_lock_ | .. running .. 532 // - This could block but the thread still | .. running .. 533 // has a state of kSuspended and so this | .. running .. 534 // isn't an issue. | .. running .. 535 // Acquire thread_suspend_count_lock_ | .. running .. 536 // - we poll here as we're transitioning into | .. running .. 537 // kRunnable and an individual thread suspend | .. running .. 538 // request (e.g for debugging) won't try | .. running .. 539 // to acquire the mutator lock (which would | .. running .. 540 // block as we hold the mutator lock). This | .. running .. 541 // poll ensures that if the suspender thought | .. running .. 542 // we were suspended by incrementing our | .. running .. 543 // Thread::suspend_count_ and then reading | .. running .. 544 // our state we go back to waiting on | .. running .. 545 // Thread::resume_cond_. | .. running .. 546 // can_go_runnable = Thread::suspend_count_ == 0 | .. running .. 547 // Release thread_suspend_count_lock_ | .. running .. 548 // if can_go_runnable | .. running .. 549 // Change state to kRunnable | .. running .. 550 // else | .. running .. 551 // Goto x | .. running .. 552 // .. running .. | .. running .. 553 static ReaderWriterMutex* mutator_lock_ ACQUIRED_AFTER(instrument_entrypoints_lock_); 554 555 // Allow reader-writer mutual exclusion on the mark and live bitmaps of the heap. 556 static ReaderWriterMutex* heap_bitmap_lock_ ACQUIRED_AFTER(mutator_lock_); 557 558 // Guards shutdown of the runtime. 559 static Mutex* runtime_shutdown_lock_ ACQUIRED_AFTER(heap_bitmap_lock_); 560 561 // Guards background profiler global state. 562 static Mutex* profiler_lock_ ACQUIRED_AFTER(runtime_shutdown_lock_); 563 564 // Guards trace (ie traceview) requests. 565 static Mutex* trace_lock_ ACQUIRED_AFTER(profiler_lock_); 566 567 // Guards debugger recent allocation records. 568 static Mutex* alloc_tracker_lock_ ACQUIRED_AFTER(trace_lock_); 569 570 // Guards updates to instrumentation to ensure mutual exclusion of 571 // events like deoptimization requests. 572 // TODO: improve name, perhaps instrumentation_update_lock_. 573 static Mutex* deoptimization_lock_ ACQUIRED_AFTER(alloc_tracker_lock_); 574 575 // The thread_list_lock_ guards ThreadList::list_. It is also commonly held to stop threads 576 // attaching and detaching. 577 static Mutex* thread_list_lock_ ACQUIRED_AFTER(deoptimization_lock_); 578 579 // Signaled when threads terminate. Used to determine when all non-daemons have terminated. 580 static ConditionVariable* thread_exit_cond_ GUARDED_BY(Locks::thread_list_lock_); 581 582 // Guards maintaining loading library data structures. 583 static Mutex* jni_libraries_lock_ ACQUIRED_AFTER(thread_list_lock_); 584 585 // Guards breakpoints. 586 static ReaderWriterMutex* breakpoint_lock_ ACQUIRED_AFTER(jni_libraries_lock_); 587 588 // Guards lists of classes within the class linker. 589 static ReaderWriterMutex* classlinker_classes_lock_ ACQUIRED_AFTER(breakpoint_lock_); 590 591 static Mutex* method_verifiers_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); 592 593 // When declaring any Mutex add DEFAULT_MUTEX_ACQUIRED_AFTER to use annotalysis to check the code 594 // doesn't try to hold a higher level Mutex. 595 #define DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_AFTER(Locks::method_verifiers_lock_) 596 597 static Mutex* allocated_monitor_ids_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); 598 599 // Guard the allocation/deallocation of thread ids. 600 static Mutex* allocated_thread_ids_lock_ ACQUIRED_AFTER(allocated_monitor_ids_lock_); 601 602 // Guards modification of the LDT on x86. 603 static Mutex* modify_ldt_lock_ ACQUIRED_AFTER(allocated_thread_ids_lock_); 604 605 // Guards intern table. 606 static Mutex* intern_table_lock_ ACQUIRED_AFTER(modify_ldt_lock_); 607 608 // Guards reference processor. 609 static Mutex* reference_processor_lock_ ACQUIRED_AFTER(intern_table_lock_); 610 611 // Guards cleared references queue. 612 static Mutex* reference_queue_cleared_references_lock_ ACQUIRED_AFTER(reference_processor_lock_); 613 614 // Guards weak references queue. 615 static Mutex* reference_queue_weak_references_lock_ ACQUIRED_AFTER(reference_queue_cleared_references_lock_); 616 617 // Guards finalizer references queue. 618 static Mutex* reference_queue_finalizer_references_lock_ ACQUIRED_AFTER(reference_queue_weak_references_lock_); 619 620 // Guards phantom references queue. 621 static Mutex* reference_queue_phantom_references_lock_ ACQUIRED_AFTER(reference_queue_finalizer_references_lock_); 622 623 // Guards soft references queue. 624 static Mutex* reference_queue_soft_references_lock_ ACQUIRED_AFTER(reference_queue_phantom_references_lock_); 625 626 // Have an exclusive aborting thread. 627 static Mutex* abort_lock_ ACQUIRED_AFTER(reference_queue_soft_references_lock_); 628 629 // Allow mutual exclusion when manipulating Thread::suspend_count_. 630 // TODO: Does the trade-off of a per-thread lock make sense? 631 static Mutex* thread_suspend_count_lock_ ACQUIRED_AFTER(abort_lock_); 632 633 // One unexpected signal at a time lock. 634 static Mutex* unexpected_signal_lock_ ACQUIRED_AFTER(thread_suspend_count_lock_); 635 636 // Guards the maps in mem_map. 637 static Mutex* mem_maps_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); 638 639 // Have an exclusive logging thread. 640 static Mutex* logging_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); 641}; 642 643} // namespace art 644 645#endif // ART_RUNTIME_BASE_MUTEX_H_ 646