mutex.h revision 37f3c968ecd04e77802fe17bb82dabc07de21ca1
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 kRosAllocGlobalLock, 64 kRosAllocBracketLock, 65 kRosAllocBulkFreeLock, 66 kAllocSpaceLock, 67 kReferenceProcessorLock, 68 kDexFileMethodInlinerLock, 69 kDexFileToMethodInlinerMapLock, 70 kMarkSweepMarkStackLock, 71 kTransactionLogLock, 72 kInternTableLock, 73 kDefaultMutexLevel, 74 kMarkSweepLargeObjectLock, 75 kPinTableLock, 76 kLoadLibraryLock, 77 kJdwpObjectRegistryLock, 78 kModifyLdtLock, 79 kAllocatedThreadIdsLock, 80 kMonitorPoolLock, 81 kClassLinkerClassesLock, 82 kBreakpointLock, 83 kMonitorLock, 84 kMonitorListLock, 85 kThreadListLock, 86 kBreakpointInvokeLock, 87 kDeoptimizationLock, 88 kTraceLock, 89 kProfilerLock, 90 kJdwpEventListLock, 91 kJdwpAttachLock, 92 kJdwpStartLock, 93 kRuntimeShutdownLock, 94 kHeapBitmapLock, 95 kMutatorLock, 96 kZygoteCreationLock, 97 98 kLockLevelCount // Must come last. 99}; 100std::ostream& operator<<(std::ostream& os, const LockLevel& rhs); 101 102const bool kDebugLocking = kIsDebugBuild; 103 104// Record Log contention information, dumpable via SIGQUIT. 105#ifdef ART_USE_FUTEXES 106// To enable lock contention logging, set this to true. 107const bool kLogLockContentions = false; 108#else 109// Keep this false as lock contention logging is supported only with 110// futex. 111const bool kLogLockContentions = false; 112#endif 113const size_t kContentionLogSize = 4; 114const size_t kContentionLogDataSize = kLogLockContentions ? 1 : 0; 115const size_t kAllMutexDataSize = kLogLockContentions ? 1 : 0; 116 117// Base class for all Mutex implementations 118class BaseMutex { 119 public: 120 const char* GetName() const { 121 return name_; 122 } 123 124 virtual bool IsMutex() const { return false; } 125 virtual bool IsReaderWriterMutex() const { return false; } 126 127 virtual void Dump(std::ostream& os) const = 0; 128 129 static void DumpAll(std::ostream& os); 130 131 protected: 132 friend class ConditionVariable; 133 134 BaseMutex(const char* name, LockLevel level); 135 virtual ~BaseMutex(); 136 void RegisterAsLocked(Thread* self); 137 void RegisterAsUnlocked(Thread* self); 138 void CheckSafeToWait(Thread* self); 139 140 friend class ScopedContentionRecorder; 141 142 void RecordContention(uint64_t blocked_tid, uint64_t owner_tid, uint64_t nano_time_blocked); 143 void DumpContention(std::ostream& os) const; 144 145 const LockLevel level_; // Support for lock hierarchy. 146 const char* const name_; 147 148 // A log entry that records contention but makes no guarantee that either tid will be held live. 149 struct ContentionLogEntry { 150 ContentionLogEntry() : blocked_tid(0), owner_tid(0) {} 151 uint64_t blocked_tid; 152 uint64_t owner_tid; 153 AtomicInteger count; 154 }; 155 struct ContentionLogData { 156 ContentionLogEntry contention_log[kContentionLogSize]; 157 // The next entry in the contention log to be updated. Value ranges from 0 to 158 // kContentionLogSize - 1. 159 AtomicInteger cur_content_log_entry; 160 // Number of times the Mutex has been contended. 161 AtomicInteger contention_count; 162 // Sum of time waited by all contenders in ns. 163 Atomic<uint64_t> wait_time; 164 void AddToWaitTime(uint64_t value); 165 ContentionLogData() : wait_time(0) {} 166 }; 167 ContentionLogData contention_log_data_[kContentionLogDataSize]; 168 169 public: 170 bool HasEverContended() const { 171 if (kLogLockContentions) { 172 return contention_log_data_->contention_count.LoadSequentiallyConsistent() > 0; 173 } 174 return false; 175 } 176}; 177 178// A Mutex is used to achieve mutual exclusion between threads. A Mutex can be used to gain 179// exclusive access to what it guards. A Mutex can be in one of two states: 180// - Free - not owned by any thread, 181// - Exclusive - owned by a single thread. 182// 183// The effect of locking and unlocking operations on the state is: 184// State | ExclusiveLock | ExclusiveUnlock 185// ------------------------------------------- 186// Free | Exclusive | error 187// Exclusive | Block* | Free 188// * Mutex is not reentrant and so an attempt to ExclusiveLock on the same thread will result in 189// an error. Being non-reentrant simplifies Waiting on ConditionVariables. 190std::ostream& operator<<(std::ostream& os, const Mutex& mu); 191class LOCKABLE Mutex : public BaseMutex { 192 public: 193 explicit Mutex(const char* name, LockLevel level = kDefaultMutexLevel, bool recursive = false); 194 ~Mutex(); 195 196 virtual bool IsMutex() const { return true; } 197 198 // Block until mutex is free then acquire exclusive access. 199 void ExclusiveLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION(); 200 void Lock(Thread* self) EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(self); } 201 202 // Returns true if acquires exclusive access, false otherwise. 203 bool ExclusiveTryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true); 204 bool TryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true) { return ExclusiveTryLock(self); } 205 206 // Release exclusive access. 207 void ExclusiveUnlock(Thread* self) UNLOCK_FUNCTION(); 208 void Unlock(Thread* self) UNLOCK_FUNCTION() { ExclusiveUnlock(self); } 209 210 // Is the current thread the exclusive holder of the Mutex. 211 bool IsExclusiveHeld(const Thread* self) const; 212 213 // Assert that the Mutex is exclusively held by the current thread. 214 void AssertExclusiveHeld(const Thread* self) { 215 if (kDebugLocking && (gAborting == 0)) { 216 CHECK(IsExclusiveHeld(self)) << *this; 217 } 218 } 219 void AssertHeld(const Thread* self) { AssertExclusiveHeld(self); } 220 221 // Assert that the Mutex is not held by the current thread. 222 void AssertNotHeldExclusive(const Thread* self) { 223 if (kDebugLocking && (gAborting == 0)) { 224 CHECK(!IsExclusiveHeld(self)) << *this; 225 } 226 } 227 void AssertNotHeld(const Thread* self) { AssertNotHeldExclusive(self); } 228 229 // Id associated with exclusive owner. No memory ordering semantics if called from a thread other 230 // than the owner. 231 uint64_t GetExclusiveOwnerTid() const; 232 233 // Returns how many times this Mutex has been locked, it is better to use AssertHeld/NotHeld. 234 unsigned int GetDepth() const { 235 return recursion_count_; 236 } 237 238 virtual void Dump(std::ostream& os) const; 239 240 private: 241#if ART_USE_FUTEXES 242 // 0 is unheld, 1 is held. 243 AtomicInteger state_; 244 // Exclusive owner. 245 volatile uint64_t exclusive_owner_; 246 // Number of waiting contenders. 247 AtomicInteger num_contenders_; 248#else 249 pthread_mutex_t mutex_; 250 volatile uint64_t exclusive_owner_; // Guarded by mutex_. 251#endif 252 const bool recursive_; // Can the lock be recursively held? 253 unsigned int recursion_count_; 254 friend class ConditionVariable; 255 DISALLOW_COPY_AND_ASSIGN(Mutex); 256}; 257 258// A ReaderWriterMutex is used to achieve mutual exclusion between threads, similar to a Mutex. 259// Unlike a Mutex a ReaderWriterMutex can be used to gain exclusive (writer) or shared (reader) 260// access to what it guards. A flaw in relation to a Mutex is that it cannot be used with a 261// condition variable. A ReaderWriterMutex can be in one of three states: 262// - Free - not owned by any thread, 263// - Exclusive - owned by a single thread, 264// - Shared(n) - shared amongst n threads. 265// 266// The effect of locking and unlocking operations on the state is: 267// 268// State | ExclusiveLock | ExclusiveUnlock | SharedLock | SharedUnlock 269// ---------------------------------------------------------------------------- 270// Free | Exclusive | error | SharedLock(1) | error 271// Exclusive | Block | Free | Block | error 272// Shared(n) | Block | error | SharedLock(n+1)* | Shared(n-1) or Free 273// * for large values of n the SharedLock may block. 274std::ostream& operator<<(std::ostream& os, const ReaderWriterMutex& mu); 275class LOCKABLE ReaderWriterMutex : public BaseMutex { 276 public: 277 explicit ReaderWriterMutex(const char* name, LockLevel level = kDefaultMutexLevel); 278 ~ReaderWriterMutex(); 279 280 virtual bool IsReaderWriterMutex() const { return true; } 281 282 // Block until ReaderWriterMutex is free then acquire exclusive access. 283 void ExclusiveLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION(); 284 void WriterLock(Thread* self) EXCLUSIVE_LOCK_FUNCTION() { ExclusiveLock(self); } 285 286 // Release exclusive access. 287 void ExclusiveUnlock(Thread* self) UNLOCK_FUNCTION(); 288 void WriterUnlock(Thread* self) UNLOCK_FUNCTION() { ExclusiveUnlock(self); } 289 290 // Block until ReaderWriterMutex is free and acquire exclusive access. Returns true on success 291 // or false if timeout is reached. 292#if HAVE_TIMED_RWLOCK 293 bool ExclusiveLockWithTimeout(Thread* self, int64_t ms, int32_t ns) 294 EXCLUSIVE_TRYLOCK_FUNCTION(true); 295#endif 296 297 // Block until ReaderWriterMutex is shared or free then acquire a share on the access. 298 void SharedLock(Thread* self) SHARED_LOCK_FUNCTION() ALWAYS_INLINE; 299 void ReaderLock(Thread* self) SHARED_LOCK_FUNCTION() { SharedLock(self); } 300 301 // Try to acquire share of ReaderWriterMutex. 302 bool SharedTryLock(Thread* self) EXCLUSIVE_TRYLOCK_FUNCTION(true); 303 304 // Release a share of the access. 305 void SharedUnlock(Thread* self) UNLOCK_FUNCTION() ALWAYS_INLINE; 306 void ReaderUnlock(Thread* self) UNLOCK_FUNCTION() { SharedUnlock(self); } 307 308 // Is the current thread the exclusive holder of the ReaderWriterMutex. 309 bool IsExclusiveHeld(const Thread* self) const; 310 311 // Assert the current thread has exclusive access to the ReaderWriterMutex. 312 void AssertExclusiveHeld(const Thread* self) { 313 if (kDebugLocking && (gAborting == 0)) { 314 CHECK(IsExclusiveHeld(self)) << *this; 315 } 316 } 317 void AssertWriterHeld(const Thread* self) { AssertExclusiveHeld(self); } 318 319 // Assert the current thread doesn't have exclusive access to the ReaderWriterMutex. 320 void AssertNotExclusiveHeld(const Thread* self) { 321 if (kDebugLocking && (gAborting == 0)) { 322 CHECK(!IsExclusiveHeld(self)) << *this; 323 } 324 } 325 void AssertNotWriterHeld(const Thread* self) { AssertNotExclusiveHeld(self); } 326 327 // Is the current thread a shared holder of the ReaderWriterMutex. 328 bool IsSharedHeld(const Thread* self) const; 329 330 // Assert the current thread has shared access to the ReaderWriterMutex. 331 void AssertSharedHeld(const Thread* self) { 332 if (kDebugLocking && (gAborting == 0)) { 333 // TODO: we can only assert this well when self != NULL. 334 CHECK(IsSharedHeld(self) || self == NULL) << *this; 335 } 336 } 337 void AssertReaderHeld(const Thread* self) { AssertSharedHeld(self); } 338 339 // Assert the current thread doesn't hold this ReaderWriterMutex either in shared or exclusive 340 // mode. 341 void AssertNotHeld(const Thread* self) { 342 if (kDebugLocking && (gAborting == 0)) { 343 CHECK(!IsSharedHeld(self)) << *this; 344 } 345 } 346 347 // Id associated with exclusive owner. No memory ordering semantics if called from a thread other 348 // than the owner. 349 uint64_t GetExclusiveOwnerTid() const; 350 351 virtual void Dump(std::ostream& os) const; 352 353 private: 354#if ART_USE_FUTEXES 355 // -1 implies held exclusive, +ve shared held by state_ many owners. 356 AtomicInteger state_; 357 // Exclusive owner. Modification guarded by this mutex. 358 volatile uint64_t exclusive_owner_; 359 // Number of contenders waiting for a reader share. 360 AtomicInteger num_pending_readers_; 361 // Number of contenders waiting to be the writer. 362 AtomicInteger num_pending_writers_; 363#else 364 pthread_rwlock_t rwlock_; 365 volatile uint64_t exclusive_owner_; // Guarded by rwlock_. 366#endif 367 DISALLOW_COPY_AND_ASSIGN(ReaderWriterMutex); 368}; 369 370// ConditionVariables allow threads to queue and sleep. Threads may then be resumed individually 371// (Signal) or all at once (Broadcast). 372class ConditionVariable { 373 public: 374 explicit ConditionVariable(const char* name, Mutex& mutex); 375 ~ConditionVariable(); 376 377 void Broadcast(Thread* self); 378 void Signal(Thread* self); 379 // TODO: No thread safety analysis on Wait and TimedWait as they call mutex operations via their 380 // pointer copy, thereby defeating annotalysis. 381 void Wait(Thread* self) NO_THREAD_SAFETY_ANALYSIS; 382 void TimedWait(Thread* self, int64_t ms, int32_t ns) NO_THREAD_SAFETY_ANALYSIS; 383 // Variant of Wait that should be used with caution. Doesn't validate that no mutexes are held 384 // when waiting. 385 // TODO: remove this. 386 void WaitHoldingLocks(Thread* self) NO_THREAD_SAFETY_ANALYSIS; 387 388 private: 389 const char* const name_; 390 // The Mutex being used by waiters. It is an error to mix condition variables between different 391 // Mutexes. 392 Mutex& guard_; 393#if ART_USE_FUTEXES 394 // A counter that is modified by signals and broadcasts. This ensures that when a waiter gives up 395 // their Mutex and another thread takes it and signals, the waiting thread observes that sequence_ 396 // changed and doesn't enter the wait. Modified while holding guard_, but is read by futex wait 397 // without guard_ held. 398 AtomicInteger sequence_; 399 // Number of threads that have come into to wait, not the length of the waiters on the futex as 400 // waiters may have been requeued onto guard_. Guarded by guard_. 401 volatile int32_t num_waiters_; 402#else 403 pthread_cond_t cond_; 404#endif 405 DISALLOW_COPY_AND_ASSIGN(ConditionVariable); 406}; 407 408// Scoped locker/unlocker for a regular Mutex that acquires mu upon construction and releases it 409// upon destruction. 410class SCOPED_LOCKABLE MutexLock { 411 public: 412 explicit MutexLock(Thread* self, Mutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : self_(self), mu_(mu) { 413 mu_.ExclusiveLock(self_); 414 } 415 416 ~MutexLock() UNLOCK_FUNCTION() { 417 mu_.ExclusiveUnlock(self_); 418 } 419 420 private: 421 Thread* const self_; 422 Mutex& mu_; 423 DISALLOW_COPY_AND_ASSIGN(MutexLock); 424}; 425// Catch bug where variable name is omitted. "MutexLock (lock);" instead of "MutexLock mu(lock)". 426#define MutexLock(x) COMPILE_ASSERT(0, mutex_lock_declaration_missing_variable_name) 427 428// Scoped locker/unlocker for a ReaderWriterMutex that acquires read access to mu upon 429// construction and releases it upon destruction. 430class SCOPED_LOCKABLE ReaderMutexLock { 431 public: 432 explicit ReaderMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : 433 self_(self), mu_(mu) { 434 mu_.SharedLock(self_); 435 } 436 437 ~ReaderMutexLock() UNLOCK_FUNCTION() { 438 mu_.SharedUnlock(self_); 439 } 440 441 private: 442 Thread* const self_; 443 ReaderWriterMutex& mu_; 444 DISALLOW_COPY_AND_ASSIGN(ReaderMutexLock); 445}; 446// Catch bug where variable name is omitted. "ReaderMutexLock (lock);" instead of 447// "ReaderMutexLock mu(lock)". 448#define ReaderMutexLock(x) COMPILE_ASSERT(0, reader_mutex_lock_declaration_missing_variable_name) 449 450// Scoped locker/unlocker for a ReaderWriterMutex that acquires write access to mu upon 451// construction and releases it upon destruction. 452class SCOPED_LOCKABLE WriterMutexLock { 453 public: 454 explicit WriterMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : 455 self_(self), mu_(mu) { 456 mu_.ExclusiveLock(self_); 457 } 458 459 ~WriterMutexLock() UNLOCK_FUNCTION() { 460 mu_.ExclusiveUnlock(self_); 461 } 462 463 private: 464 Thread* const self_; 465 ReaderWriterMutex& mu_; 466 DISALLOW_COPY_AND_ASSIGN(WriterMutexLock); 467}; 468// Catch bug where variable name is omitted. "WriterMutexLock (lock);" instead of 469// "WriterMutexLock mu(lock)". 470#define WriterMutexLock(x) COMPILE_ASSERT(0, writer_mutex_lock_declaration_missing_variable_name) 471 472// Global mutexes corresponding to the levels above. 473class Locks { 474 public: 475 static void Init(); 476 477 // The mutator_lock_ is used to allow mutators to execute in a shared (reader) mode or to block 478 // mutators by having an exclusive (writer) owner. In normal execution each mutator thread holds 479 // a share on the mutator_lock_. The garbage collector may also execute with shared access but 480 // at times requires exclusive access to the heap (not to be confused with the heap meta-data 481 // guarded by the heap_lock_ below). When the garbage collector requires exclusive access it asks 482 // the mutators to suspend themselves which also involves usage of the thread_suspend_count_lock_ 483 // to cover weaknesses in using ReaderWriterMutexes with ConditionVariables. We use a condition 484 // variable to wait upon in the suspension logic as releasing and then re-acquiring a share on 485 // the mutator lock doesn't necessarily allow the exclusive user (e.g the garbage collector) 486 // chance to acquire the lock. 487 // 488 // Thread suspension: 489 // Shared users | Exclusive user 490 // (holding mutator lock and in kRunnable state) | .. running .. 491 // .. running .. | Request thread suspension by: 492 // .. running .. | - acquiring thread_suspend_count_lock_ 493 // .. running .. | - incrementing Thread::suspend_count_ on 494 // .. running .. | all mutator threads 495 // .. running .. | - releasing thread_suspend_count_lock_ 496 // .. running .. | Block trying to acquire exclusive mutator lock 497 // Poll Thread::suspend_count_ and enter full | .. blocked .. 498 // suspend code. | .. blocked .. 499 // Change state to kSuspended | .. blocked .. 500 // x: Release share on mutator_lock_ | Carry out exclusive access 501 // Acquire thread_suspend_count_lock_ | .. exclusive .. 502 // while Thread::suspend_count_ > 0 | .. exclusive .. 503 // - wait on Thread::resume_cond_ | .. exclusive .. 504 // (releases thread_suspend_count_lock_) | .. exclusive .. 505 // .. waiting .. | Release mutator_lock_ 506 // .. waiting .. | Request thread resumption by: 507 // .. waiting .. | - acquiring thread_suspend_count_lock_ 508 // .. waiting .. | - decrementing Thread::suspend_count_ on 509 // .. waiting .. | all mutator threads 510 // .. waiting .. | - notifying on Thread::resume_cond_ 511 // - re-acquire thread_suspend_count_lock_ | - releasing thread_suspend_count_lock_ 512 // Release thread_suspend_count_lock_ | .. running .. 513 // Acquire share on mutator_lock_ | .. running .. 514 // - This could block but the thread still | .. running .. 515 // has a state of kSuspended and so this | .. running .. 516 // isn't an issue. | .. running .. 517 // Acquire thread_suspend_count_lock_ | .. running .. 518 // - we poll here as we're transitioning into | .. running .. 519 // kRunnable and an individual thread suspend | .. running .. 520 // request (e.g for debugging) won't try | .. running .. 521 // to acquire the mutator lock (which would | .. running .. 522 // block as we hold the mutator lock). This | .. running .. 523 // poll ensures that if the suspender thought | .. running .. 524 // we were suspended by incrementing our | .. running .. 525 // Thread::suspend_count_ and then reading | .. running .. 526 // our state we go back to waiting on | .. running .. 527 // Thread::resume_cond_. | .. running .. 528 // can_go_runnable = Thread::suspend_count_ == 0 | .. running .. 529 // Release thread_suspend_count_lock_ | .. running .. 530 // if can_go_runnable | .. running .. 531 // Change state to kRunnable | .. running .. 532 // else | .. running .. 533 // Goto x | .. running .. 534 // .. running .. | .. running .. 535 static ReaderWriterMutex* mutator_lock_; 536 537 // Allow reader-writer mutual exclusion on the mark and live bitmaps of the heap. 538 static ReaderWriterMutex* heap_bitmap_lock_ ACQUIRED_AFTER(mutator_lock_); 539 540 // Guards shutdown of the runtime. 541 static Mutex* runtime_shutdown_lock_ ACQUIRED_AFTER(heap_bitmap_lock_); 542 543 // Guards background profiler global state. 544 static Mutex* profiler_lock_ ACQUIRED_AFTER(runtime_shutdown_lock_); 545 546 // Guards trace (ie traceview) requests. 547 static Mutex* trace_lock_ ACQUIRED_AFTER(profiler_lock_); 548 549 // The thread_list_lock_ guards ThreadList::list_. It is also commonly held to stop threads 550 // attaching and detaching. 551 static Mutex* thread_list_lock_ ACQUIRED_AFTER(trace_lock_); 552 553 // Guards breakpoints. 554 static Mutex* breakpoint_lock_ ACQUIRED_AFTER(thread_list_lock_); 555 556 // Guards lists of classes within the class linker. 557 static ReaderWriterMutex* classlinker_classes_lock_ ACQUIRED_AFTER(breakpoint_lock_); 558 559 // When declaring any Mutex add DEFAULT_MUTEX_ACQUIRED_AFTER to use annotalysis to check the code 560 // doesn't try to hold a higher level Mutex. 561 #define DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_AFTER(Locks::classlinker_classes_lock_) 562 563 static Mutex* allocated_monitor_ids_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); 564 565 // Guard the allocation/deallocation of thread ids. 566 static Mutex* allocated_thread_ids_lock_ ACQUIRED_AFTER(allocated_monitor_ids_lock_); 567 568 // Guards modification of the LDT on x86. 569 static Mutex* modify_ldt_lock_ ACQUIRED_AFTER(allocated_thread_ids_lock_); 570 571 // Guards intern table. 572 static Mutex* intern_table_lock_ ACQUIRED_AFTER(modify_ldt_lock_); 573 574 // Have an exclusive aborting thread. 575 static Mutex* abort_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); 576 577 // Allow mutual exclusion when manipulating Thread::suspend_count_. 578 // TODO: Does the trade-off of a per-thread lock make sense? 579 static Mutex* thread_suspend_count_lock_ ACQUIRED_AFTER(abort_lock_); 580 581 // One unexpected signal at a time lock. 582 static Mutex* unexpected_signal_lock_ ACQUIRED_AFTER(thread_suspend_count_lock_); 583 584 // Guards the maps in mem_map. 585 static Mutex* mem_maps_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); 586 587 // Have an exclusive logging thread. 588 static Mutex* logging_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); 589}; 590 591} // namespace art 592 593#endif // ART_RUNTIME_BASE_MUTEX_H_ 594