/* * 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_THREAD_LIST_H_ #define ART_RUNTIME_THREAD_LIST_H_ #include "barrier.h" #include "base/histogram.h" #include "base/mutex.h" #include "base/value_object.h" #include "jni.h" #include "reflective_handle_scope.h" #include "suspend_reason.h" #include #include #include namespace art { namespace gc { namespace collector { class GarbageCollector; } // namespace collector class GcPauseListener; } // namespace gc class Closure; class IsMarkedVisitor; class RootVisitor; class Thread; class TimingLogger; enum VisitRootFlags : uint8_t; class ThreadList { public: static constexpr uint32_t kMaxThreadId = 0xFFFF; static constexpr uint32_t kInvalidThreadId = 0; static constexpr uint32_t kMainThreadId = 1; static constexpr uint64_t kDefaultThreadSuspendTimeout = kIsDebugBuild ? 50'000'000'000ull : 10'000'000'000ull; explicit ThreadList(uint64_t thread_suspend_timeout_ns); ~ThreadList(); void ShutDown(); void DumpForSigQuit(std::ostream& os) REQUIRES(!Locks::thread_list_lock_, !Locks::mutator_lock_); // For thread suspend timeout dumps. void Dump(std::ostream& os, bool dump_native_stack = true) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); pid_t GetLockOwner(); // For SignalCatcher. // Thread suspension support. void ResumeAll() REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_) UNLOCK_FUNCTION(Locks::mutator_lock_); bool Resume(Thread* thread, SuspendReason reason = SuspendReason::kInternal) REQUIRES(!Locks::thread_suspend_count_lock_) WARN_UNUSED; // Suspends all threads and gets exclusive access to the mutator lock. // If long_suspend is true, then other threads who try to suspend will never timeout. // long_suspend is currenly used for hprof since large heaps take a long time. void SuspendAll(const char* cause, bool long_suspend = false) EXCLUSIVE_LOCK_FUNCTION(Locks::mutator_lock_) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_, !Locks::mutator_lock_); // Suspend a thread using a peer, typically used by the debugger. Returns the thread on success, // else null. The peer is used to identify the thread to avoid races with the thread terminating. // If the thread should be suspended then value of request_suspension should be true otherwise // the routine will wait for a previous suspend request. If the suspension times out then *timeout // is set to true. Thread* SuspendThreadByPeer(jobject peer, bool request_suspension, SuspendReason reason, bool* timed_out) REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); // Suspend a thread using its thread id, typically used by lock/monitor inflation. Returns the // thread on success else null. The thread id is used to identify the thread to avoid races with // the thread terminating. Note that as thread ids are recycled this may not suspend the expected // thread, that may be terminating. If the suspension times out then *timeout is set to true. Thread* SuspendThreadByThreadId(uint32_t thread_id, SuspendReason reason, bool* timed_out) REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); // Find an existing thread (or self) by its thread id (not tid). Thread* FindThreadByThreadId(uint32_t thread_id) REQUIRES(Locks::thread_list_lock_); // Find an existing thread (or self) by its tid (not thread id). Thread* FindThreadByTid(int tid) REQUIRES(Locks::thread_list_lock_); // Does the thread list still contain the given thread, or one at the same address? // Used by Monitor to provide (mostly accurate) debugging information. bool Contains(Thread* thread) REQUIRES(Locks::thread_list_lock_); // Run a checkpoint on all threads. Return the total number of threads for which the checkpoint // function has been or will be called. // Running threads are not suspended but run the checkpoint inside of the suspend check. The // return value includes already suspended threads for b/24191051. Runs or requests the // callback, if non-null, inside the thread_list_lock critical section after determining the // runnable/suspended states of the threads. Does not wait for completion of the callbacks in // running threads. size_t RunCheckpoint(Closure* checkpoint_function, Closure* callback = nullptr) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); // Run an empty checkpoint on threads. Wait until threads pass the next suspend point or are // suspended. This is used to ensure that the threads finish or aren't in the middle of an // in-flight mutator heap access (eg. a read barrier.) Runnable threads will respond by // decrementing the empty checkpoint barrier count. This works even when the weak ref access is // disabled. Only one concurrent use is currently supported. void RunEmptyCheckpoint() REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); // Flip thread roots from from-space refs to to-space refs. Used by // the concurrent copying collector. size_t FlipThreadRoots(Closure* thread_flip_visitor, Closure* flip_callback, gc::collector::GarbageCollector* collector, gc::GcPauseListener* pause_listener) REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); // Iterates over all the threads. void ForEach(void (*callback)(Thread*, void*), void* context) REQUIRES(Locks::thread_list_lock_); template void ForEach(CallBack cb) REQUIRES(Locks::thread_list_lock_) { ForEach([](Thread* t, void* ctx) REQUIRES(Locks::thread_list_lock_) { (*reinterpret_cast(ctx))(t); }, &cb); } // Add/remove current thread from list. void Register(Thread* self) REQUIRES(Locks::runtime_shutdown_lock_) REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); void Unregister(Thread* self) REQUIRES(!Locks::mutator_lock_, !Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); void VisitRoots(RootVisitor* visitor, VisitRootFlags flags) const REQUIRES_SHARED(Locks::mutator_lock_); void VisitRootsForSuspendedThreads(RootVisitor* visitor) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_) REQUIRES_SHARED(Locks::mutator_lock_); void VisitReflectiveTargets(ReflectiveValueVisitor* visitor) const REQUIRES(Locks::mutator_lock_); // Return a copy of the thread list. std::list GetList() REQUIRES(Locks::thread_list_lock_) { return list_; } void DumpNativeStacks(std::ostream& os) REQUIRES(!Locks::thread_list_lock_); Barrier* EmptyCheckpointBarrier() { return empty_checkpoint_barrier_.get(); } void SweepInterpreterCaches(IsMarkedVisitor* visitor) const REQUIRES(!Locks::thread_list_lock_) REQUIRES_SHARED(Locks::mutator_lock_); void WaitForOtherNonDaemonThreadsToExit(bool check_no_birth = true) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_, !Locks::mutator_lock_); private: uint32_t AllocThreadId(Thread* self); void ReleaseThreadId(Thread* self, uint32_t id) REQUIRES(!Locks::allocated_thread_ids_lock_); size_t RunCheckpoint(Closure* checkpoint_function, bool includeSuspended) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); void DumpUnattachedThreads(std::ostream& os, bool dump_native_stack) REQUIRES(!Locks::thread_list_lock_); void SuspendAllDaemonThreadsForShutdown() REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); void SuspendAllInternal(Thread* self, Thread* ignore1, Thread* ignore2 = nullptr, SuspendReason reason = SuspendReason::kInternal) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); void AssertThreadsAreSuspended(Thread* self, Thread* ignore1, Thread* ignore2 = nullptr) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_); std::bitset allocated_ids_ GUARDED_BY(Locks::allocated_thread_ids_lock_); // The actual list of all threads. std::list list_ GUARDED_BY(Locks::thread_list_lock_); // Ongoing suspend all requests, used to ensure threads added to list_ respect SuspendAll. int suspend_all_count_ GUARDED_BY(Locks::thread_suspend_count_lock_); // Number of threads unregistering, ~ThreadList blocks until this hits 0. int unregistering_count_ GUARDED_BY(Locks::thread_list_lock_); // Thread suspend time histogram. Only modified when all the threads are suspended, so guarding // by mutator lock ensures no thread can read when another thread is modifying it. Histogram suspend_all_historam_ GUARDED_BY(Locks::mutator_lock_); // Whether or not the current thread suspension is long. bool long_suspend_; // Whether the shutdown function has been called. This is checked in the destructor. It is an // error to destroy a ThreadList instance without first calling ShutDown(). bool shut_down_; // Thread suspension timeout in nanoseconds. const uint64_t thread_suspend_timeout_ns_; std::unique_ptr empty_checkpoint_barrier_; friend class Thread; DISALLOW_COPY_AND_ASSIGN(ThreadList); }; // Helper for suspending all threads and getting exclusive access to the mutator lock. class ScopedSuspendAll : public ValueObject { public: explicit ScopedSuspendAll(const char* cause, bool long_suspend = false) EXCLUSIVE_LOCK_FUNCTION(Locks::mutator_lock_) REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_, !Locks::mutator_lock_); // No REQUIRES(mutator_lock_) since the unlock function already asserts this. ~ScopedSuspendAll() REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_) UNLOCK_FUNCTION(Locks::mutator_lock_); }; } // namespace art #endif // ART_RUNTIME_THREAD_LIST_H_