| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef ART_RUNTIME_BASE_MUTEX_H_ |
| #define ART_RUNTIME_BASE_MUTEX_H_ |
| |
| #include <pthread.h> |
| #include <stdint.h> |
| |
| #include <iosfwd> |
| #include <string> |
| |
| #include "atomic.h" |
| #include "base/logging.h" |
| #include "base/macros.h" |
| #include "globals.h" |
| |
| #if defined(__APPLE__) |
| #define ART_USE_FUTEXES 0 |
| #else |
| #define ART_USE_FUTEXES 1 |
| #endif |
| |
| // Currently Darwin doesn't support locks with timeouts. |
| #if !defined(__APPLE__) |
| #define HAVE_TIMED_RWLOCK 1 |
| #else |
| #define HAVE_TIMED_RWLOCK 0 |
| #endif |
| |
| namespace art { |
| |
| class SHARED_LOCKABLE ReaderWriterMutex; |
| class SHARED_LOCKABLE MutatorMutex; |
| class ScopedContentionRecorder; |
| class Thread; |
| |
| // LockLevel is used to impose a lock hierarchy [1] where acquisition of a Mutex at a higher or |
| // equal level to a lock a thread holds is invalid. The lock hierarchy achieves a cycle free |
| // partial ordering and thereby cause deadlock situations to fail checks. |
| // |
| // [1] http://www.drdobbs.com/parallel/use-lock-hierarchies-to-avoid-deadlock/204801163 |
| enum LockLevel { |
| kLoggingLock = 0, |
| kMemMapsLock, |
| kSwapMutexesLock, |
| kUnexpectedSignalLock, |
| kThreadSuspendCountLock, |
| kAbortLock, |
| kJdwpSocketLock, |
| kRegionSpaceRegionLock, |
| kRosAllocGlobalLock, |
| kRosAllocBracketLock, |
| kRosAllocBulkFreeLock, |
| kMarkSweepMarkStackLock, |
| kTransactionLogLock, |
| kJniWeakGlobalsLock, |
| kJniGlobalsLock, |
| kReferenceQueueSoftReferencesLock, |
| kReferenceQueuePhantomReferencesLock, |
| kReferenceQueueFinalizerReferencesLock, |
| kReferenceQueueWeakReferencesLock, |
| kReferenceQueueClearedReferencesLock, |
| kReferenceProcessorLock, |
| kJitDebugInterfaceLock, |
| kAllocSpaceLock, |
| kBumpPointerSpaceBlockLock, |
| kArenaPoolLock, |
| kInternTableLock, |
| kOatFileSecondaryLookupLock, |
| kHostDlOpenHandlesLock, |
| kVerifierDepsLock, |
| kOatFileManagerLock, |
| kTracingUniqueMethodsLock, |
| kTracingStreamingLock, |
| kDeoptimizedMethodsLock, |
| kClassLoaderClassesLock, |
| kDefaultMutexLevel, |
| kDexLock, |
| kMarkSweepLargeObjectLock, |
| kJdwpObjectRegistryLock, |
| kModifyLdtLock, |
| kAllocatedThreadIdsLock, |
| kMonitorPoolLock, |
| kClassLinkerClassesLock, // TODO rename. |
| kJitCodeCacheLock, |
| kBreakpointLock, |
| kMonitorLock, |
| kMonitorListLock, |
| kJniLoadLibraryLock, |
| kThreadListLock, |
| kAllocTrackerLock, |
| kDeoptimizationLock, |
| kProfilerLock, |
| kJdwpShutdownLock, |
| kJdwpEventListLock, |
| kJdwpAttachLock, |
| kJdwpStartLock, |
| kRuntimeShutdownLock, |
| kTraceLock, |
| kHeapBitmapLock, |
| kMutatorLock, |
| kInstrumentEntrypointsLock, |
| kZygoteCreationLock, |
| |
| kLockLevelCount // Must come last. |
| }; |
| std::ostream& operator<<(std::ostream& os, const LockLevel& rhs); |
| |
| const bool kDebugLocking = kIsDebugBuild; |
| |
| // Record Log contention information, dumpable via SIGQUIT. |
| #ifdef ART_USE_FUTEXES |
| // To enable lock contention logging, set this to true. |
| const bool kLogLockContentions = false; |
| #else |
| // Keep this false as lock contention logging is supported only with |
| // futex. |
| const bool kLogLockContentions = false; |
| #endif |
| const size_t kContentionLogSize = 4; |
| const size_t kContentionLogDataSize = kLogLockContentions ? 1 : 0; |
| const size_t kAllMutexDataSize = kLogLockContentions ? 1 : 0; |
| |
| // Base class for all Mutex implementations |
| class BaseMutex { |
| public: |
| const char* GetName() const { |
| return name_; |
| } |
| |
| virtual bool IsMutex() const { return false; } |
| virtual bool IsReaderWriterMutex() const { return false; } |
| virtual bool IsMutatorMutex() const { return false; } |
| |
| virtual void Dump(std::ostream& os) const = 0; |
| |
| static void DumpAll(std::ostream& os); |
| |
| protected: |
| friend class ConditionVariable; |
| |
| BaseMutex(const char* name, LockLevel level); |
| virtual ~BaseMutex(); |
| void RegisterAsLocked(Thread* self); |
| void RegisterAsUnlocked(Thread* self); |
| void CheckSafeToWait(Thread* self); |
| |
| friend class ScopedContentionRecorder; |
| |
| void RecordContention(uint64_t blocked_tid, uint64_t owner_tid, uint64_t nano_time_blocked); |
| void DumpContention(std::ostream& os) const; |
| |
| const LockLevel level_; // Support for lock hierarchy. |
| const char* const name_; |
| |
| // A log entry that records contention but makes no guarantee that either tid will be held live. |
| struct ContentionLogEntry { |
| ContentionLogEntry() : blocked_tid(0), owner_tid(0) {} |
| uint64_t blocked_tid; |
| uint64_t owner_tid; |
| AtomicInteger count; |
| }; |
| struct ContentionLogData { |
| ContentionLogEntry contention_log[kContentionLogSize]; |
| // The next entry in the contention log to be updated. Value ranges from 0 to |
| // kContentionLogSize - 1. |
| AtomicInteger cur_content_log_entry; |
| // Number of times the Mutex has been contended. |
| AtomicInteger contention_count; |
| // Sum of time waited by all contenders in ns. |
| Atomic<uint64_t> wait_time; |
| void AddToWaitTime(uint64_t value); |
| ContentionLogData() : wait_time(0) {} |
| }; |
| ContentionLogData contention_log_data_[kContentionLogDataSize]; |
| |
| public: |
| bool HasEverContended() const { |
| if (kLogLockContentions) { |
| return contention_log_data_->contention_count.LoadSequentiallyConsistent() > 0; |
| } |
| return false; |
| } |
| }; |
| |
| // A Mutex is used to achieve mutual exclusion between threads. A Mutex can be used to gain |
| // exclusive access to what it guards. A Mutex can be in one of two states: |
| // - Free - not owned by any thread, |
| // - Exclusive - owned by a single thread. |
| // |
| // The effect of locking and unlocking operations on the state is: |
| // State | ExclusiveLock | ExclusiveUnlock |
| // ------------------------------------------- |
| // Free | Exclusive | error |
| // Exclusive | Block* | Free |
| // * Mutex is not reentrant and so an attempt to ExclusiveLock on the same thread will result in |
| // an error. Being non-reentrant simplifies Waiting on ConditionVariables. |
| std::ostream& operator<<(std::ostream& os, const Mutex& mu); |
| class LOCKABLE Mutex : public BaseMutex { |
| public: |
| explicit Mutex(const char* name, LockLevel level = kDefaultMutexLevel, bool recursive = false); |
| ~Mutex(); |
| |
| virtual bool IsMutex() const { return true; } |
| |
| // Block until mutex is free then acquire exclusive access. |
| void ExclusiveLock(Thread* self) ACQUIRE(); |
| void Lock(Thread* self) ACQUIRE() { ExclusiveLock(self); } |
| |
| // Returns true if acquires exclusive access, false otherwise. |
| bool ExclusiveTryLock(Thread* self) TRY_ACQUIRE(true); |
| bool TryLock(Thread* self) TRY_ACQUIRE(true) { return ExclusiveTryLock(self); } |
| |
| // Release exclusive access. |
| void ExclusiveUnlock(Thread* self) RELEASE(); |
| void Unlock(Thread* self) RELEASE() { ExclusiveUnlock(self); } |
| |
| // Is the current thread the exclusive holder of the Mutex. |
| bool IsExclusiveHeld(const Thread* self) const; |
| |
| // Assert that the Mutex is exclusively held by the current thread. |
| void AssertExclusiveHeld(const Thread* self) ASSERT_CAPABILITY(this) { |
| if (kDebugLocking && (gAborting == 0)) { |
| CHECK(IsExclusiveHeld(self)) << *this; |
| } |
| } |
| void AssertHeld(const Thread* self) ASSERT_CAPABILITY(this) { AssertExclusiveHeld(self); } |
| |
| // Assert that the Mutex is not held by the current thread. |
| void AssertNotHeldExclusive(const Thread* self) ASSERT_CAPABILITY(!*this) { |
| if (kDebugLocking && (gAborting == 0)) { |
| CHECK(!IsExclusiveHeld(self)) << *this; |
| } |
| } |
| void AssertNotHeld(const Thread* self) ASSERT_CAPABILITY(!*this) { |
| AssertNotHeldExclusive(self); |
| } |
| |
| // Id associated with exclusive owner. No memory ordering semantics if called from a thread other |
| // than the owner. |
| uint64_t GetExclusiveOwnerTid() const; |
| |
| // Returns how many times this Mutex has been locked, it is better to use AssertHeld/NotHeld. |
| unsigned int GetDepth() const { |
| return recursion_count_; |
| } |
| |
| virtual void Dump(std::ostream& os) const; |
| |
| // For negative capabilities in clang annotations. |
| const Mutex& operator!() const { return *this; } |
| |
| private: |
| #if ART_USE_FUTEXES |
| // 0 is unheld, 1 is held. |
| AtomicInteger state_; |
| // Exclusive owner. |
| volatile uint64_t exclusive_owner_; |
| // Number of waiting contenders. |
| AtomicInteger num_contenders_; |
| #else |
| pthread_mutex_t mutex_; |
| volatile uint64_t exclusive_owner_; // Guarded by mutex_. |
| #endif |
| const bool recursive_; // Can the lock be recursively held? |
| unsigned int recursion_count_; |
| friend class ConditionVariable; |
| DISALLOW_COPY_AND_ASSIGN(Mutex); |
| }; |
| |
| // A ReaderWriterMutex is used to achieve mutual exclusion between threads, similar to a Mutex. |
| // Unlike a Mutex a ReaderWriterMutex can be used to gain exclusive (writer) or shared (reader) |
| // access to what it guards. A flaw in relation to a Mutex is that it cannot be used with a |
| // condition variable. A ReaderWriterMutex can be in one of three states: |
| // - Free - not owned by any thread, |
| // - Exclusive - owned by a single thread, |
| // - Shared(n) - shared amongst n threads. |
| // |
| // The effect of locking and unlocking operations on the state is: |
| // |
| // State | ExclusiveLock | ExclusiveUnlock | SharedLock | SharedUnlock |
| // ---------------------------------------------------------------------------- |
| // Free | Exclusive | error | SharedLock(1) | error |
| // Exclusive | Block | Free | Block | error |
| // Shared(n) | Block | error | SharedLock(n+1)* | Shared(n-1) or Free |
| // * for large values of n the SharedLock may block. |
| std::ostream& operator<<(std::ostream& os, const ReaderWriterMutex& mu); |
| class SHARED_LOCKABLE ReaderWriterMutex : public BaseMutex { |
| public: |
| explicit ReaderWriterMutex(const char* name, LockLevel level = kDefaultMutexLevel); |
| ~ReaderWriterMutex(); |
| |
| virtual bool IsReaderWriterMutex() const { return true; } |
| |
| // Block until ReaderWriterMutex is free then acquire exclusive access. |
| void ExclusiveLock(Thread* self) ACQUIRE(); |
| void WriterLock(Thread* self) ACQUIRE() { ExclusiveLock(self); } |
| |
| // Release exclusive access. |
| void ExclusiveUnlock(Thread* self) RELEASE(); |
| void WriterUnlock(Thread* self) RELEASE() { ExclusiveUnlock(self); } |
| |
| // Block until ReaderWriterMutex is free and acquire exclusive access. Returns true on success |
| // or false if timeout is reached. |
| #if HAVE_TIMED_RWLOCK |
| bool ExclusiveLockWithTimeout(Thread* self, int64_t ms, int32_t ns) |
| EXCLUSIVE_TRYLOCK_FUNCTION(true); |
| #endif |
| |
| // Block until ReaderWriterMutex is shared or free then acquire a share on the access. |
| void SharedLock(Thread* self) ACQUIRE_SHARED() ALWAYS_INLINE; |
| void ReaderLock(Thread* self) ACQUIRE_SHARED() { SharedLock(self); } |
| |
| // Try to acquire share of ReaderWriterMutex. |
| bool SharedTryLock(Thread* self) SHARED_TRYLOCK_FUNCTION(true); |
| |
| // Release a share of the access. |
| void SharedUnlock(Thread* self) RELEASE_SHARED() ALWAYS_INLINE; |
| void ReaderUnlock(Thread* self) RELEASE_SHARED() { SharedUnlock(self); } |
| |
| // Is the current thread the exclusive holder of the ReaderWriterMutex. |
| bool IsExclusiveHeld(const Thread* self) const; |
| |
| // Assert the current thread has exclusive access to the ReaderWriterMutex. |
| void AssertExclusiveHeld(const Thread* self) ASSERT_CAPABILITY(this) { |
| if (kDebugLocking && (gAborting == 0)) { |
| CHECK(IsExclusiveHeld(self)) << *this; |
| } |
| } |
| void AssertWriterHeld(const Thread* self) ASSERT_CAPABILITY(this) { AssertExclusiveHeld(self); } |
| |
| // Assert the current thread doesn't have exclusive access to the ReaderWriterMutex. |
| void AssertNotExclusiveHeld(const Thread* self) ASSERT_CAPABILITY(!this) { |
| if (kDebugLocking && (gAborting == 0)) { |
| CHECK(!IsExclusiveHeld(self)) << *this; |
| } |
| } |
| void AssertNotWriterHeld(const Thread* self) ASSERT_CAPABILITY(!this) { |
| AssertNotExclusiveHeld(self); |
| } |
| |
| // Is the current thread a shared holder of the ReaderWriterMutex. |
| bool IsSharedHeld(const Thread* self) const; |
| |
| // Assert the current thread has shared access to the ReaderWriterMutex. |
| void AssertSharedHeld(const Thread* self) ASSERT_SHARED_CAPABILITY(this) { |
| if (kDebugLocking && (gAborting == 0)) { |
| // TODO: we can only assert this well when self != null. |
| CHECK(IsSharedHeld(self) || self == nullptr) << *this; |
| } |
| } |
| void AssertReaderHeld(const Thread* self) ASSERT_SHARED_CAPABILITY(this) { |
| AssertSharedHeld(self); |
| } |
| |
| // Assert the current thread doesn't hold this ReaderWriterMutex either in shared or exclusive |
| // mode. |
| void AssertNotHeld(const Thread* self) ASSERT_SHARED_CAPABILITY(!this) { |
| if (kDebugLocking && (gAborting == 0)) { |
| CHECK(!IsSharedHeld(self)) << *this; |
| } |
| } |
| |
| // Id associated with exclusive owner. No memory ordering semantics if called from a thread other |
| // than the owner. |
| uint64_t GetExclusiveOwnerTid() const; |
| |
| virtual void Dump(std::ostream& os) const; |
| |
| // For negative capabilities in clang annotations. |
| const ReaderWriterMutex& operator!() const { return *this; } |
| |
| private: |
| #if ART_USE_FUTEXES |
| // Out-of-inline path for handling contention for a SharedLock. |
| void HandleSharedLockContention(Thread* self, int32_t cur_state); |
| |
| // -1 implies held exclusive, +ve shared held by state_ many owners. |
| AtomicInteger state_; |
| // Exclusive owner. Modification guarded by this mutex. |
| volatile uint64_t exclusive_owner_; |
| // Number of contenders waiting for a reader share. |
| AtomicInteger num_pending_readers_; |
| // Number of contenders waiting to be the writer. |
| AtomicInteger num_pending_writers_; |
| #else |
| pthread_rwlock_t rwlock_; |
| volatile uint64_t exclusive_owner_; // Guarded by rwlock_. |
| #endif |
| DISALLOW_COPY_AND_ASSIGN(ReaderWriterMutex); |
| }; |
| |
| // MutatorMutex is a special kind of ReaderWriterMutex created specifically for the |
| // Locks::mutator_lock_ mutex. The behaviour is identical to the ReaderWriterMutex except that |
| // thread state changes also play a part in lock ownership. The mutator_lock_ will not be truly |
| // held by any mutator threads. However, a thread in the kRunnable state is considered to have |
| // shared ownership of the mutator lock and therefore transitions in and out of the kRunnable |
| // state have associated implications on lock ownership. Extra methods to handle the state |
| // transitions have been added to the interface but are only accessible to the methods dealing |
| // with state transitions. The thread state and flags attributes are used to ensure thread state |
| // transitions are consistent with the permitted behaviour of the mutex. |
| // |
| // *) The most important consequence of this behaviour is that all threads must be in one of the |
| // suspended states before exclusive ownership of the mutator mutex is sought. |
| // |
| std::ostream& operator<<(std::ostream& os, const MutatorMutex& mu); |
| class SHARED_LOCKABLE MutatorMutex : public ReaderWriterMutex { |
| public: |
| explicit MutatorMutex(const char* name, LockLevel level = kDefaultMutexLevel) |
| : ReaderWriterMutex(name, level) {} |
| ~MutatorMutex() {} |
| |
| virtual bool IsMutatorMutex() const { return true; } |
| |
| // For negative capabilities in clang annotations. |
| const MutatorMutex& operator!() const { return *this; } |
| |
| private: |
| friend class Thread; |
| void TransitionFromRunnableToSuspended(Thread* self) UNLOCK_FUNCTION() ALWAYS_INLINE; |
| void TransitionFromSuspendedToRunnable(Thread* self) SHARED_LOCK_FUNCTION() ALWAYS_INLINE; |
| |
| DISALLOW_COPY_AND_ASSIGN(MutatorMutex); |
| }; |
| |
| // ConditionVariables allow threads to queue and sleep. Threads may then be resumed individually |
| // (Signal) or all at once (Broadcast). |
| class ConditionVariable { |
| public: |
| ConditionVariable(const char* name, Mutex& mutex); |
| ~ConditionVariable(); |
| |
| void Broadcast(Thread* self); |
| void Signal(Thread* self); |
| // TODO: No thread safety analysis on Wait and TimedWait as they call mutex operations via their |
| // pointer copy, thereby defeating annotalysis. |
| void Wait(Thread* self) NO_THREAD_SAFETY_ANALYSIS; |
| bool TimedWait(Thread* self, int64_t ms, int32_t ns) NO_THREAD_SAFETY_ANALYSIS; |
| // Variant of Wait that should be used with caution. Doesn't validate that no mutexes are held |
| // when waiting. |
| // TODO: remove this. |
| void WaitHoldingLocks(Thread* self) NO_THREAD_SAFETY_ANALYSIS; |
| |
| private: |
| const char* const name_; |
| // The Mutex being used by waiters. It is an error to mix condition variables between different |
| // Mutexes. |
| Mutex& guard_; |
| #if ART_USE_FUTEXES |
| // A counter that is modified by signals and broadcasts. This ensures that when a waiter gives up |
| // their Mutex and another thread takes it and signals, the waiting thread observes that sequence_ |
| // changed and doesn't enter the wait. Modified while holding guard_, but is read by futex wait |
| // without guard_ held. |
| AtomicInteger sequence_; |
| // Number of threads that have come into to wait, not the length of the waiters on the futex as |
| // waiters may have been requeued onto guard_. Guarded by guard_. |
| volatile int32_t num_waiters_; |
| #else |
| pthread_cond_t cond_; |
| #endif |
| DISALLOW_COPY_AND_ASSIGN(ConditionVariable); |
| }; |
| |
| // Scoped locker/unlocker for a regular Mutex that acquires mu upon construction and releases it |
| // upon destruction. |
| class SCOPED_CAPABILITY MutexLock { |
| public: |
| MutexLock(Thread* self, Mutex& mu) ACQUIRE(mu) : self_(self), mu_(mu) { |
| mu_.ExclusiveLock(self_); |
| } |
| |
| ~MutexLock() RELEASE() { |
| mu_.ExclusiveUnlock(self_); |
| } |
| |
| private: |
| Thread* const self_; |
| Mutex& mu_; |
| DISALLOW_COPY_AND_ASSIGN(MutexLock); |
| }; |
| // Catch bug where variable name is omitted. "MutexLock (lock);" instead of "MutexLock mu(lock)". |
| #define MutexLock(x) static_assert(0, "MutexLock declaration missing variable name") |
| |
| // Scoped locker/unlocker for a ReaderWriterMutex that acquires read access to mu upon |
| // construction and releases it upon destruction. |
| class SCOPED_CAPABILITY ReaderMutexLock { |
| public: |
| ReaderMutexLock(Thread* self, ReaderWriterMutex& mu) ACQUIRE(mu) : |
| self_(self), mu_(mu) { |
| mu_.SharedLock(self_); |
| } |
| |
| ~ReaderMutexLock() RELEASE() { |
| mu_.SharedUnlock(self_); |
| } |
| |
| private: |
| Thread* const self_; |
| ReaderWriterMutex& mu_; |
| DISALLOW_COPY_AND_ASSIGN(ReaderMutexLock); |
| }; |
| // Catch bug where variable name is omitted. "ReaderMutexLock (lock);" instead of |
| // "ReaderMutexLock mu(lock)". |
| #define ReaderMutexLock(x) static_assert(0, "ReaderMutexLock declaration missing variable name") |
| |
| // Scoped locker/unlocker for a ReaderWriterMutex that acquires write access to mu upon |
| // construction and releases it upon destruction. |
| class SCOPED_CAPABILITY WriterMutexLock { |
| public: |
| WriterMutexLock(Thread* self, ReaderWriterMutex& mu) EXCLUSIVE_LOCK_FUNCTION(mu) : |
| self_(self), mu_(mu) { |
| mu_.ExclusiveLock(self_); |
| } |
| |
| ~WriterMutexLock() UNLOCK_FUNCTION() { |
| mu_.ExclusiveUnlock(self_); |
| } |
| |
| private: |
| Thread* const self_; |
| ReaderWriterMutex& mu_; |
| DISALLOW_COPY_AND_ASSIGN(WriterMutexLock); |
| }; |
| // Catch bug where variable name is omitted. "WriterMutexLock (lock);" instead of |
| // "WriterMutexLock mu(lock)". |
| #define WriterMutexLock(x) static_assert(0, "WriterMutexLock declaration missing variable name") |
| |
| // For StartNoThreadSuspension and EndNoThreadSuspension. |
| class CAPABILITY("role") Role { |
| public: |
| void Acquire() ACQUIRE() {} |
| void Release() RELEASE() {} |
| const Role& operator!() const { return *this; } |
| }; |
| |
| class Uninterruptible : public Role { |
| }; |
| |
| // Global mutexes corresponding to the levels above. |
| class Locks { |
| public: |
| static void Init(); |
| static void InitConditions() NO_THREAD_SAFETY_ANALYSIS; // Condition variables. |
| |
| // Destroying various lock types can emit errors that vary depending upon |
| // whether the client (art::Runtime) is currently active. Allow the client |
| // to set a callback that is used to check when it is acceptable to call |
| // Abort. The default behavior is that the client *is not* able to call |
| // Abort if no callback is established. |
| using ClientCallback = bool(); |
| static void SetClientCallback(ClientCallback* is_safe_to_call_abort_cb) NO_THREAD_SAFETY_ANALYSIS; |
| // Checks for whether it is safe to call Abort() without using locks. |
| static bool IsSafeToCallAbortRacy() NO_THREAD_SAFETY_ANALYSIS; |
| |
| |
| // Guards allocation entrypoint instrumenting. |
| static Mutex* instrument_entrypoints_lock_; |
| |
| // A barrier is used to synchronize the GC/Debugger thread with mutator threads. When GC/Debugger |
| // thread wants to suspend all mutator threads, it needs to wait for all mutator threads to pass |
| // a barrier. Threads that are already suspended will get their barrier passed by the GC/Debugger |
| // thread; threads in the runnable state will pass the barrier when they transit to the suspended |
| // state. GC/Debugger thread will be woken up when all mutator threads are suspended. |
| // |
| // Thread suspension: |
| // mutator thread | GC/Debugger |
| // .. running .. | .. running .. |
| // .. running .. | Request thread suspension by: |
| // .. running .. | - acquiring thread_suspend_count_lock_ |
| // .. running .. | - incrementing Thread::suspend_count_ on |
| // .. running .. | all mutator threads |
| // .. running .. | - releasing thread_suspend_count_lock_ |
| // .. running .. | Block wait for all threads to pass a barrier |
| // Poll Thread::suspend_count_ and enter full | .. blocked .. |
| // suspend code. | .. blocked .. |
| // Change state to kSuspended (pass the barrier) | Wake up when all threads pass the barrier |
| // x: Acquire thread_suspend_count_lock_ | .. running .. |
| // while Thread::suspend_count_ > 0 | .. running .. |
| // - wait on Thread::resume_cond_ | .. running .. |
| // (releases thread_suspend_count_lock_) | .. running .. |
| // .. waiting .. | Request thread resumption by: |
| // .. waiting .. | - acquiring thread_suspend_count_lock_ |
| // .. waiting .. | - decrementing Thread::suspend_count_ on |
| // .. waiting .. | all mutator threads |
| // .. waiting .. | - notifying on Thread::resume_cond_ |
| // - re-acquire thread_suspend_count_lock_ | - releasing thread_suspend_count_lock_ |
| // Release thread_suspend_count_lock_ | .. running .. |
| // Change to kRunnable | .. running .. |
| // - this uses a CAS operation to ensure the | .. running .. |
| // suspend request flag isn't raised as the | .. running .. |
| // state is changed | .. running .. |
| // - if the CAS operation fails then goto x | .. running .. |
| // .. running .. | .. running .. |
| static MutatorMutex* mutator_lock_ ACQUIRED_AFTER(instrument_entrypoints_lock_); |
| |
| // Allow reader-writer mutual exclusion on the mark and live bitmaps of the heap. |
| static ReaderWriterMutex* heap_bitmap_lock_ ACQUIRED_AFTER(mutator_lock_); |
| |
| // Guards shutdown of the runtime. |
| static Mutex* runtime_shutdown_lock_ ACQUIRED_AFTER(heap_bitmap_lock_); |
| |
| // Guards background profiler global state. |
| static Mutex* profiler_lock_ ACQUIRED_AFTER(runtime_shutdown_lock_); |
| |
| // Guards trace (ie traceview) requests. |
| static Mutex* trace_lock_ ACQUIRED_AFTER(profiler_lock_); |
| |
| // Guards debugger recent allocation records. |
| static Mutex* alloc_tracker_lock_ ACQUIRED_AFTER(trace_lock_); |
| |
| // Guards updates to instrumentation to ensure mutual exclusion of |
| // events like deoptimization requests. |
| // TODO: improve name, perhaps instrumentation_update_lock_. |
| static Mutex* deoptimization_lock_ ACQUIRED_AFTER(alloc_tracker_lock_); |
| |
| // The thread_list_lock_ guards ThreadList::list_. It is also commonly held to stop threads |
| // attaching and detaching. |
| static Mutex* thread_list_lock_ ACQUIRED_AFTER(deoptimization_lock_); |
| |
| // Signaled when threads terminate. Used to determine when all non-daemons have terminated. |
| static ConditionVariable* thread_exit_cond_ GUARDED_BY(Locks::thread_list_lock_); |
| |
| // Guards maintaining loading library data structures. |
| static Mutex* jni_libraries_lock_ ACQUIRED_AFTER(thread_list_lock_); |
| |
| // Guards breakpoints. |
| static ReaderWriterMutex* breakpoint_lock_ ACQUIRED_AFTER(jni_libraries_lock_); |
| |
| // Guards lists of classes within the class linker. |
| static ReaderWriterMutex* classlinker_classes_lock_ ACQUIRED_AFTER(breakpoint_lock_); |
| |
| // When declaring any Mutex add DEFAULT_MUTEX_ACQUIRED_AFTER to use annotalysis to check the code |
| // doesn't try to hold a higher level Mutex. |
| #define DEFAULT_MUTEX_ACQUIRED_AFTER ACQUIRED_AFTER(Locks::classlinker_classes_lock_) |
| |
| static Mutex* allocated_monitor_ids_lock_ ACQUIRED_AFTER(classlinker_classes_lock_); |
| |
| // Guard the allocation/deallocation of thread ids. |
| static Mutex* allocated_thread_ids_lock_ ACQUIRED_AFTER(allocated_monitor_ids_lock_); |
| |
| // Guards modification of the LDT on x86. |
| static Mutex* modify_ldt_lock_ ACQUIRED_AFTER(allocated_thread_ids_lock_); |
| |
| // Guards opened oat files in OatFileManager. |
| static ReaderWriterMutex* oat_file_manager_lock_ ACQUIRED_AFTER(modify_ldt_lock_); |
| |
| // Guards extra string entries for VerifierDeps. |
| static ReaderWriterMutex* verifier_deps_lock_ ACQUIRED_AFTER(oat_file_manager_lock_); |
| |
| // Guards dlopen_handles_ in DlOpenOatFile. |
| static Mutex* host_dlopen_handles_lock_ ACQUIRED_AFTER(verifier_deps_lock_); |
| |
| // Guards intern table. |
| static Mutex* intern_table_lock_ ACQUIRED_AFTER(host_dlopen_handles_lock_); |
| |
| // Guards reference processor. |
| static Mutex* reference_processor_lock_ ACQUIRED_AFTER(intern_table_lock_); |
| |
| // Guards cleared references queue. |
| static Mutex* reference_queue_cleared_references_lock_ ACQUIRED_AFTER(reference_processor_lock_); |
| |
| // Guards weak references queue. |
| static Mutex* reference_queue_weak_references_lock_ ACQUIRED_AFTER(reference_queue_cleared_references_lock_); |
| |
| // Guards finalizer references queue. |
| static Mutex* reference_queue_finalizer_references_lock_ ACQUIRED_AFTER(reference_queue_weak_references_lock_); |
| |
| // Guards phantom references queue. |
| static Mutex* reference_queue_phantom_references_lock_ ACQUIRED_AFTER(reference_queue_finalizer_references_lock_); |
| |
| // Guards soft references queue. |
| static Mutex* reference_queue_soft_references_lock_ ACQUIRED_AFTER(reference_queue_phantom_references_lock_); |
| |
| // Guard accesses to the JNI Global Reference table. |
| static ReaderWriterMutex* jni_globals_lock_ ACQUIRED_AFTER(reference_queue_soft_references_lock_); |
| |
| // Guard accesses to the JNI Weak Global Reference table. |
| static Mutex* jni_weak_globals_lock_ ACQUIRED_AFTER(jni_globals_lock_); |
| |
| // Have an exclusive aborting thread. |
| static Mutex* abort_lock_ ACQUIRED_AFTER(jni_weak_globals_lock_); |
| |
| // Allow mutual exclusion when manipulating Thread::suspend_count_. |
| // TODO: Does the trade-off of a per-thread lock make sense? |
| static Mutex* thread_suspend_count_lock_ ACQUIRED_AFTER(abort_lock_); |
| |
| // One unexpected signal at a time lock. |
| static Mutex* unexpected_signal_lock_ ACQUIRED_AFTER(thread_suspend_count_lock_); |
| |
| // Guards the maps in mem_map. |
| static Mutex* mem_maps_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); |
| |
| // Have an exclusive logging thread. |
| static Mutex* logging_lock_ ACQUIRED_AFTER(unexpected_signal_lock_); |
| }; |
| |
| class Roles { |
| public: |
| // Uninterruptible means that the thread may not become suspended. |
| static Uninterruptible uninterruptible_; |
| }; |
| |
| } // namespace art |
| |
| #endif // ART_RUNTIME_BASE_MUTEX_H_ |