mutex.h revision 310008008c90fea246efd00cb99ee7ded97c5209
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 kTransactionLogLock, 65 kReferenceQueueSoftReferencesLock, 66 kReferenceQueuePhantomReferencesLock, 67 kReferenceQueueFinalizerReferencesLock, 68 kReferenceQueueWeakReferencesLock, 69 kReferenceQueueClearedReferencesLock, 70 kReferenceProcessorLock, 71 kJitCodeCacheLock, 72 kRosAllocGlobalLock, 73 kRosAllocBracketLock, 74 kRosAllocBulkFreeLock, 75 kAllocSpaceLock, 76 kBumpPointerSpaceBlockLock, 77 kArenaPoolLock, 78 kDexFileMethodInlinerLock, 79 kDexFileToMethodInlinerMapLock, 80 kMarkSweepMarkStackLock, 81 kInternTableLock, 82 kOatFileSecondaryLookupLock, 83 kDefaultMutexLevel, 84 kMarkSweepLargeObjectLock, 85 kPinTableLock, 86 kJdwpObjectRegistryLock, 87 kModifyLdtLock, 88 kAllocatedThreadIdsLock, 89 kMonitorPoolLock, 90 kMethodVerifiersLock, 91 kClassLinkerClassesLock, 92 kBreakpointLock, 93 kMonitorLock, 94 kMonitorListLock, 95 kJniLoadLibraryLock, 96 kThreadListLock, 97 kAllocTrackerLock, 98 kDeoptimizationLock, 99 kProfilerLock, 100 kJdwpShutdownLock, 101 kJdwpEventListLock, 102 kJdwpAttachLock, 103 kJdwpStartLock, 104 kRuntimeShutdownLock, 105 kTraceLock, 106 kHeapBitmapLock, 107 kMutatorLock, 108 kInstrumentEntrypointsLock, 109 kZygoteCreationLock, 110 111 kLockLevelCount // Must come last. 112}; 113std::ostream& operator<<(std::ostream& os, const LockLevel& rhs); 114 115const bool kDebugLocking = kIsDebugBuild; 116 117// Record Log contention information, dumpable via SIGQUIT. 118#ifdef ART_USE_FUTEXES 119// To enable lock contention logging, set this to true. 120const bool kLogLockContentions = false; 121#else 122// Keep this false as lock contention logging is supported only with 123// futex. 124const bool kLogLockContentions = false; 125#endif 126const size_t kContentionLogSize = 4; 127const size_t kContentionLogDataSize = kLogLockContentions ? 1 : 0; 128const size_t kAllMutexDataSize = kLogLockContentions ? 1 : 0; 129 130// Base class for all Mutex implementations 131class BaseMutex { 132 public: 133 const char* GetName() const { 134 return name_; 135 } 136 137 virtual bool IsMutex() const { return false; } 138 virtual bool IsReaderWriterMutex() const { return false; } 139 140 virtual void Dump(std::ostream& os) const = 0; 141 142 static void DumpAll(std::ostream& os); 143 144 protected: 145 friend class ConditionVariable; 146 147 BaseMutex(const char* name, LockLevel level); 148 virtual ~BaseMutex(); 149 void RegisterAsLocked(Thread* self); 150 void RegisterAsUnlocked(Thread* self); 151 void CheckSafeToWait(Thread* self); 152 153 friend class ScopedContentionRecorder; 154 155 void RecordContention(uint64_t blocked_tid, uint64_t owner_tid, uint64_t nano_time_blocked); 156 void DumpContention(std::ostream& os) const; 157 158 const LockLevel level_; // Support for lock hierarchy. 159 const char* const name_; 160 161 // A log entry that records contention but makes no guarantee that either tid will be held live. 162 struct ContentionLogEntry { 163 ContentionLogEntry() : blocked_tid(0), owner_tid(0) {} 164 uint64_t blocked_tid; 165 uint64_t owner_tid; 166 AtomicInteger count; 167 }; 168 struct ContentionLogData { 169 ContentionLogEntry contention_log[kContentionLogSize]; 170 // The next entry in the contention log to be updated. Value ranges from 0 to 171 // kContentionLogSize - 1. 172 AtomicInteger cur_content_log_entry; 173 // Number of times the Mutex has been contended. 174 AtomicInteger contention_count; 175 // Sum of time waited by all contenders in ns. 176 Atomic<uint64_t> wait_time; 177 void AddToWaitTime(uint64_t value); 178 ContentionLogData() : wait_time(0) {} 179 }; 180 ContentionLogData contention_log_data_[kContentionLogDataSize]; 181 182 public: 183 bool HasEverContended() const { 184 if (kLogLockContentions) { 185 return contention_log_data_->contention_count.LoadSequentiallyConsistent() > 0; 186 } 187 return false; 188 } 189}; 190 191// A Mutex is used to achieve mutual exclusion between threads. A Mutex can be used to gain 192// exclusive access to what it guards. A Mutex can be in one of two states: 193// - Free - not owned by any thread, 194// - Exclusive - owned by a single thread. 195// 196// The effect of locking and unlocking operations on the state is: 197// State | ExclusiveLock | ExclusiveUnlock 198// ------------------------------------------- 199// Free | Exclusive | error 200// Exclusive | Block* | Free 201// * Mutex is not reentrant and so an attempt to ExclusiveLock on the same thread will result in 202// an error. Being non-reentrant simplifies Waiting on ConditionVariables. 203std::ostream& operator<<(std::ostream& os, const Mutex& mu); 204class LOCKABLE Mutex : public BaseMutex { 205 public: 206 explicit Mutex(const char* name, LockLevel level = kDefaultMutexLevel, bool recursive = false); 207 ~Mutex(); 208 209 virtual bool IsMutex() const { return true; } 210 211 // Block until mutex is free then acquire exclusive access. 212 void ExclusiveLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION(); 213 void Lock(Thread* self) EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(self); } 214 215 // Returns true if acquires exclusive access, false otherwise. 216 bool ExclusiveTryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true); 217 bool TryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true) { return ExclusiveTryLock(self); } 218 219 // Release exclusive access. 220 void ExclusiveUnlock(Thread* self) UNLOCK_FUNCTION(); 221 void Unlock(Thread* self) UNLOCK_FUNCTION() { ExclusiveUnlock(self); } 222 223 // Is the current thread the exclusive holder of the Mutex. 224 bool IsExclusiveHeld(const Thread* self) const; 225 226 // Assert that the Mutex is exclusively held by the current thread. 227 void AssertExclusiveHeld(const Thread* self) { 228 if (kDebugLocking && (gAborting == 0)) { 229 CHECK(IsExclusiveHeld(self)) << *this; 230 } 231 } 232 void AssertHeld(const Thread* self) { AssertExclusiveHeld(self); } 233 234 // Assert that the Mutex is not held by the current thread. 235 void AssertNotHeldExclusive(const Thread* self) { 236 if (kDebugLocking && (gAborting == 0)) { 237 CHECK(!IsExclusiveHeld(self)) << *this; 238 } 239 } 240 void AssertNotHeld(const Thread* self) { AssertNotHeldExclusive(self); } 241 242 // Id associated with exclusive owner. No memory ordering semantics if called from a thread other 243 // than the owner. 244 uint64_t GetExclusiveOwnerTid() const; 245 246 // Returns how many times this Mutex has been locked, it is better to use AssertHeld/NotHeld. 247 unsigned int GetDepth() const { 248 return recursion_count_; 249 } 250 251 virtual void Dump(std::ostream& os) const; 252 253 private: 254#if ART_USE_FUTEXES 255 // 0 is unheld, 1 is held. 256 AtomicInteger state_; 257 // Exclusive owner. 258 volatile uint64_t exclusive_owner_; 259 // Number of waiting contenders. 260 AtomicInteger num_contenders_; 261#else 262 pthread_mutex_t mutex_; 263 volatile uint64_t exclusive_owner_; // Guarded by mutex_. 264#endif 265 const bool recursive_; // Can the lock be recursively held? 266 unsigned int recursion_count_; 267 friend class ConditionVariable; 268 DISALLOW_COPY_AND_ASSIGN(Mutex); 269}; 270 271// A ReaderWriterMutex is used to achieve mutual exclusion between threads, similar to a Mutex. 272// Unlike a Mutex a ReaderWriterMutex can be used to gain exclusive (writer) or shared (reader) 273// access to what it guards. A flaw in relation to a Mutex is that it cannot be used with a 274// condition variable. A ReaderWriterMutex can be in one of three states: 275// - Free - not owned by any thread, 276// - Exclusive - owned by a single thread, 277// - Shared(n) - shared amongst n threads. 278// 279// The effect of locking and unlocking operations on the state is: 280// 281// State | ExclusiveLock | ExclusiveUnlock | SharedLock | SharedUnlock 282// ---------------------------------------------------------------------------- 283// Free | Exclusive | error | SharedLock(1) | error 284// Exclusive | Block | Free | Block | error 285// Shared(n) | Block | error | SharedLock(n+1)* | Shared(n-1) or Free 286// * for large values of n the SharedLock may block. 287std::ostream& operator<<(std::ostream& os, const ReaderWriterMutex& mu); 288class LOCKABLE ReaderWriterMutex : public BaseMutex { 289 public: 290 explicit ReaderWriterMutex(const char* name, LockLevel level = kDefaultMutexLevel); 291 ~ReaderWriterMutex(); 292 293 virtual bool IsReaderWriterMutex() const { return true; } 294 295 // Block until ReaderWriterMutex is free then acquire exclusive access. 296 void ExclusiveLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION(); 297 void WriterLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(self); } 298 299 // Release exclusive access. 300 void ExclusiveUnlock(Thread* self) UNLOCK_FUNCTION(); 301 void WriterUnlock(Thread* self) UNLOCK_FUNCTION() { ExclusiveUnlock(self); } 302 303 // Block until ReaderWriterMutex is free and acquire exclusive access. Returns true on success 304 // or false if timeout is reached. 305#if HAVE_TIMED_RWLOCK 306 bool ExclusiveLockWithTimeout(Thread* self, int64_t ms, int32_t ns) 307 EXCLUSIVE_TRYLOCK_FUNCTION(true); 308#endif 309 310 // Block until ReaderWriterMutex is shared or free then acquire a share on the access. 311 void SharedLock(Thread* self) SHARED_LOCK_FUNCTION() ALWAYS_INLINE; 312 void ReaderLock(Thread* self) SHARED_LOCK_FUNCTION() { SharedLock(self); } 313 314 // Try to acquire share of ReaderWriterMutex. 315 bool SharedTryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true); 316 317 // Release a share of the access. 318 void SharedUnlock(Thread* self) UNLOCK_FUNCTION() ALWAYS_INLINE; 319 void ReaderUnlock(Thread* self) UNLOCK_FUNCTION() { SharedUnlock(self); } 320 321 // Is the current thread the exclusive holder of the ReaderWriterMutex. 322 bool IsExclusiveHeld(const Thread* self) const; 323 324 // Assert the current thread has exclusive access to the ReaderWriterMutex. 325 void AssertExclusiveHeld(const Thread* self) { 326 if (kDebugLocking && (gAborting == 0)) { 327 CHECK(IsExclusiveHeld(self)) << *this; 328 } 329 } 330 void AssertWriterHeld(const Thread* self) { AssertExclusiveHeld(self); } 331 332 // Assert the current thread doesn't have exclusive access to the ReaderWriterMutex. 333 void AssertNotExclusiveHeld(const Thread* self) { 334 if (kDebugLocking && (gAborting == 0)) { 335 CHECK(!IsExclusiveHeld(self)) << *this; 336 } 337 } 338 void AssertNotWriterHeld(const Thread* self) { AssertNotExclusiveHeld(self); } 339 340 // Is the current thread a shared holder of the ReaderWriterMutex. 341 bool IsSharedHeld(const Thread* self) const; 342 343 // Assert the current thread has shared access to the ReaderWriterMutex. 344 void AssertSharedHeld(const Thread* self) { 345 if (kDebugLocking && (gAborting == 0)) { 346 // TODO: we can only assert this well when self != null. 347 CHECK(IsSharedHeld(self) || self == nullptr) << *this; 348 } 349 } 350 void AssertReaderHeld(const Thread* self) { AssertSharedHeld(self); } 351 352 // Assert the current thread doesn't hold this ReaderWriterMutex either in shared or exclusive 353 // mode. 354 void AssertNotHeld(const Thread* self) { 355 if (kDebugLocking && (gAborting == 0)) { 356 CHECK(!IsSharedHeld(self)) << *this; 357 } 358 } 359 360 // Id associated with exclusive owner. No memory ordering semantics if called from a thread other 361 // than the owner. 362 uint64_t GetExclusiveOwnerTid() const; 363 364 virtual void Dump(std::ostream& os) const; 365 366 private: 367#if ART_USE_FUTEXES 368 // Out-of-inline path for handling contention for a SharedLock. 369 void HandleSharedLockContention(Thread* self, int32_t cur_state); 370 371 // -1 implies held exclusive, +ve shared held by state_ many owners. 372 AtomicInteger state_; 373 // Exclusive owner. Modification guarded by this mutex. 374 volatile uint64_t exclusive_owner_; 375 // Number of contenders waiting for a reader share. 376 AtomicInteger num_pending_readers_; 377 // Number of contenders waiting to be the writer. 378 AtomicInteger num_pending_writers_; 379#else 380 pthread_rwlock_t rwlock_; 381 volatile uint64_t exclusive_owner_; // Guarded by rwlock_. 382#endif 383 DISALLOW_COPY_AND_ASSIGN(ReaderWriterMutex); 384}; 385 386// ConditionVariables allow threads to queue and sleep. Threads may then be resumed individually 387// (Signal) or all at once (Broadcast). 388class ConditionVariable { 389 public: 390 explicit ConditionVariable(const char* name, Mutex& mutex); 391 ~ConditionVariable(); 392 393 void Broadcast(Thread* self); 394 void Signal(Thread* self); 395 // TODO: No thread safety analysis on Wait and TimedWait as they call mutex operations via their 396 // pointer copy, thereby defeating annotalysis. 397 void Wait(Thread* self) NO_THREAD_SAFETY_ANALYSIS; 398 bool TimedWait(Thread* self, int64_t ms, int32_t ns) NO_THREAD_SAFETY_ANALYSIS; 399 // Variant of Wait that should be used with caution. Doesn't validate that no mutexes are held 400 // when waiting. 401 // TODO: remove this. 402 void WaitHoldingLocks(Thread* self) NO_THREAD_SAFETY_ANALYSIS; 403 404 private: 405 const char* const name_; 406 // The Mutex being used by waiters. It is an error to mix condition variables between different 407 // Mutexes. 408 Mutex& guard_; 409#if ART_USE_FUTEXES 410 // A counter that is modified by signals and broadcasts. This ensures that when a waiter gives up 411 // their Mutex and another thread takes it and signals, the waiting thread observes that sequence_ 412 // changed and doesn't enter the wait. Modified while holding guard_, but is read by futex wait 413 // without guard_ held. 414 AtomicInteger sequence_; 415 // Number of threads that have come into to wait, not the length of the waiters on the futex as 416 // waiters may have been requeued onto guard_. Guarded by guard_. 417 volatile int32_t num_waiters_; 418#else 419 pthread_cond_t cond_; 420#endif 421 DISALLOW_COPY_AND_ASSIGN(ConditionVariable); 422}; 423 424// Scoped locker/unlocker for a regular Mutex that acquires mu upon construction and releases it 425// upon destruction. 426class SCOPED_LOCKABLE MutexLock { 427 public: 428 explicit MutexLock(Thread* self, Mutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : self_(self), mu_(mu) { 429 mu_.ExclusiveLock(self_); 430 } 431 432 ~MutexLock() UNLOCK_FUNCTION() { 433 mu_.ExclusiveUnlock(self_); 434 } 435 436 private: 437 Thread* const self_; 438 Mutex& mu_; 439 DISALLOW_COPY_AND_ASSIGN(MutexLock); 440}; 441// Catch bug where variable name is omitted. "MutexLock (lock);" instead of "MutexLock mu(lock)". 442#define MutexLock(x) static_assert(0, "MutexLock declaration missing variable name") 443 444// Scoped locker/unlocker for a ReaderWriterMutex that acquires read access to mu upon 445// construction and releases it upon destruction. 446class SCOPED_LOCKABLE ReaderMutexLock { 447 public: 448 explicit ReaderMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : 449 self_(self), mu_(mu) { 450 mu_.SharedLock(self_); 451 } 452 453 ~ReaderMutexLock() UNLOCK_FUNCTION() { 454 mu_.SharedUnlock(self_); 455 } 456 457 private: 458 Thread* const self_; 459 ReaderWriterMutex& mu_; 460 DISALLOW_COPY_AND_ASSIGN(ReaderMutexLock); 461}; 462// Catch bug where variable name is omitted. "ReaderMutexLock (lock);" instead of 463// "ReaderMutexLock mu(lock)". 464#define ReaderMutexLock(x) static_assert(0, "ReaderMutexLock declaration missing variable name") 465 466// Scoped locker/unlocker for a ReaderWriterMutex that acquires write access to mu upon 467// construction and releases it upon destruction. 468class SCOPED_LOCKABLE WriterMutexLock { 469 public: 470 explicit WriterMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : 471 self_(self), mu_(mu) { 472 mu_.ExclusiveLock(self_); 473 } 474 475 ~WriterMutexLock() UNLOCK_FUNCTION() { 476 mu_.ExclusiveUnlock(self_); 477 } 478 479 private: 480 Thread* const self_; 481 ReaderWriterMutex& mu_; 482 DISALLOW_COPY_AND_ASSIGN(WriterMutexLock); 483}; 484// Catch bug where variable name is omitted. "WriterMutexLock (lock);" instead of 485// "WriterMutexLock mu(lock)". 486#define WriterMutexLock(x) static_assert(0, "WriterMutexLock declaration missing variable name") 487 488// Global mutexes corresponding to the levels above. 489class Locks { 490 public: 491 static void Init(); 492 static void InitConditions() NO_THREAD_SAFETY_ANALYSIS; // Condition variables. 493 // Guards allocation entrypoint instrumenting. 494 static Mutex* instrument_entrypoints_lock_; 495 496 // The mutator_lock_ is used to allow mutators to execute in a shared (reader) mode or to block 497 // mutators by having an exclusive (writer) owner. In normal execution each mutator thread holds 498 // a share on the mutator_lock_. The garbage collector may also execute with shared access but 499 // at times requires exclusive access to the heap (not to be confused with the heap meta-data 500 // guarded by the heap_lock_ below). When the garbage collector requires exclusive access it asks 501 // the mutators to suspend themselves which also involves usage of the thread_suspend_count_lock_ 502 // to cover weaknesses in using ReaderWriterMutexes with ConditionVariables. We use a condition 503 // variable to wait upon in the suspension logic as releasing and then re-acquiring a share on 504 // the mutator lock doesn't necessarily allow the exclusive user (e.g the garbage collector) 505 // chance to acquire the lock. 506 // 507 // Thread suspension: 508 // Shared users | Exclusive user 509 // (holding mutator lock and in kRunnable state) | .. running .. 510 // .. running .. | Request thread suspension by: 511 // .. running .. | - acquiring thread_suspend_count_lock_ 512 // .. running .. | - incrementing Thread::suspend_count_ on 513 // .. running .. | all mutator threads 514 // .. running .. | - releasing thread_suspend_count_lock_ 515 // .. running .. | Block trying to acquire exclusive mutator lock 516 // Poll Thread::suspend_count_ and enter full | .. blocked .. 517 // suspend code. | .. blocked .. 518 // Change state to kSuspended | .. blocked .. 519 // x: Release share on mutator_lock_ | Carry out exclusive access 520 // Acquire thread_suspend_count_lock_ | .. exclusive .. 521 // while Thread::suspend_count_ > 0 | .. exclusive .. 522 // - wait on Thread::resume_cond_ | .. exclusive .. 523 // (releases thread_suspend_count_lock_) | .. exclusive .. 524 // .. waiting .. | Release mutator_lock_ 525 // .. waiting .. | Request thread resumption by: 526 // .. waiting .. | - acquiring thread_suspend_count_lock_ 527 // .. waiting .. | - decrementing Thread::suspend_count_ on 528 // .. waiting .. | all mutator threads 529 // .. waiting .. | - notifying on Thread::resume_cond_ 530 // - re-acquire thread_suspend_count_lock_ | - releasing thread_suspend_count_lock_ 531 // Release thread_suspend_count_lock_ | .. running .. 532 // Acquire share on mutator_lock_ | .. running .. 533 // - This could block but the thread still | .. running .. 534 // has a state of kSuspended and so this | .. running .. 535 // isn't an issue. | .. running .. 536 // Acquire thread_suspend_count_lock_ | .. running .. 537 // - we poll here as we're transitioning into | .. running .. 538 // kRunnable and an individual thread suspend | .. running .. 539 // request (e.g for debugging) won't try | .. running .. 540 // to acquire the mutator lock (which would | .. running .. 541 // block as we hold the mutator lock). This | .. running .. 542 // poll ensures that if the suspender thought | .. running .. 543 // we were suspended by incrementing our | .. running .. 544 // Thread::suspend_count_ and then reading | .. running .. 545 // our state we go back to waiting on | .. running .. 546 // Thread::resume_cond_. | .. running .. 547 // can_go_runnable = Thread::suspend_count_ == 0 | .. running .. 548 // Release thread_suspend_count_lock_ | .. running .. 549 // if can_go_runnable | .. running .. 550 // Change state to kRunnable | .. running .. 551 // else | .. running .. 552 // Goto x | .. running .. 553 // .. running .. | .. running .. 554 static ReaderWriterMutex* mutator_lock_ ACQUIRED_AFTER(instrument_entrypoints_lock_); 555 556 // Allow reader-writer mutual exclusion on the mark and live bitmaps of the heap. 557 static ReaderWriterMutex* heap_bitmap_lock_ ACQUIRED_AFTER(mutator_lock_); 558 559 // Guards shutdown of the runtime. 560 static Mutex* runtime_shutdown_lock_ ACQUIRED_AFTER(heap_bitmap_lock_); 561 562 // Guards background profiler global state. 563 static Mutex* profiler_lock_ ACQUIRED_AFTER(runtime_shutdown_lock_); 564 565 // Guards trace (ie traceview) requests. 566 static Mutex* trace_lock_ ACQUIRED_AFTER(profiler_lock_); 567 568 // Guards debugger recent allocation records. 569 static Mutex* alloc_tracker_lock_ ACQUIRED_AFTER(trace_lock_); 570 571 // Guards updates to instrumentation to ensure mutual exclusion of 572 // events like deoptimization requests. 573 // TODO: improve name, perhaps instrumentation_update_lock_. 574 static Mutex* deoptimization_lock_ ACQUIRED_AFTER(alloc_tracker_lock_); 575 576 // The thread_list_lock_ guards ThreadList::list_. It is also commonly held to stop threads 577 // attaching and detaching. 578 static Mutex* thread_list_lock_ ACQUIRED_AFTER(deoptimization_lock_); 579 580 // Signaled when threads terminate. Used to determine when all non-daemons have terminated. 581 static ConditionVariable* thread_exit_cond_ GUARDED_BY(Locks::thread_list_lock_); 582 583 // Guards maintaining loading library data structures. 584 static Mutex* jni_libraries_lock_ ACQUIRED_AFTER(thread_list_lock_); 585 586 // Guards breakpoints. 587 static ReaderWriterMutex* breakpoint_lock_ ACQUIRED_AFTER(jni_libraries_lock_); 588 589 // Guards lists of classes within the class linker. 590 static ReaderWriterMutex* classlinker_classes_lock_ ACQUIRED_AFTER(breakpoint_lock_); 591 592 // When declaring any Mutex add DEFAULT_MUTEX_ACQUIRED_AFTER to use annotalysis to check the code 593 // doesn't try to hold a higher level Mutex. 594 #define DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_AFTER(Locks::classlinker_classes_lock_) 595 596 static Mutex* allocated_monitor_ids_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); 597 598 // Guard the allocation/deallocation of thread ids. 599 static Mutex* allocated_thread_ids_lock_ ACQUIRED_AFTER(allocated_monitor_ids_lock_); 600 601 // Guards modification of the LDT on x86. 602 static Mutex* modify_ldt_lock_ ACQUIRED_AFTER(allocated_thread_ids_lock_); 603 604 // Guards intern table. 605 static Mutex* intern_table_lock_ ACQUIRED_AFTER(modify_ldt_lock_); 606 607 // Guards reference processor. 608 static Mutex* reference_processor_lock_ ACQUIRED_AFTER(intern_table_lock_); 609 610 // Guards cleared references queue. 611 static Mutex* reference_queue_cleared_references_lock_ ACQUIRED_AFTER(reference_processor_lock_); 612 613 // Guards weak references queue. 614 static Mutex* reference_queue_weak_references_lock_ ACQUIRED_AFTER(reference_queue_cleared_references_lock_); 615 616 // Guards finalizer references queue. 617 static Mutex* reference_queue_finalizer_references_lock_ ACQUIRED_AFTER(reference_queue_weak_references_lock_); 618 619 // Guards phantom references queue. 620 static Mutex* reference_queue_phantom_references_lock_ ACQUIRED_AFTER(reference_queue_finalizer_references_lock_); 621 622 // Guards soft references queue. 623 static Mutex* reference_queue_soft_references_lock_ ACQUIRED_AFTER(reference_queue_phantom_references_lock_); 624 625 // Have an exclusive aborting thread. 626 static Mutex* abort_lock_ ACQUIRED_AFTER(reference_queue_soft_references_lock_); 627 628 // Allow mutual exclusion when manipulating Thread::suspend_count_. 629 // TODO: Does the trade-off of a per-thread lock make sense? 630 static Mutex* thread_suspend_count_lock_ ACQUIRED_AFTER(abort_lock_); 631 632 // One unexpected signal at a time lock. 633 static Mutex* unexpected_signal_lock_ ACQUIRED_AFTER(thread_suspend_count_lock_); 634 635 // Guards the maps in mem_map. 636 static Mutex* mem_maps_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); 637 638 // Have an exclusive logging thread. 639 static Mutex* logging_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); 640}; 641 642} // namespace art 643 644#endif // ART_RUNTIME_BASE_MUTEX_H_ 645