/*
* 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/time_utils.h"
#include "base/value_object.h"
#include "gc_root.h"
#include "jni.h"
#include "object_callbacks.h"
#include <bitset>
#include <list>
#include <vector>
namespace art {
namespace gc {
namespace collector {
class GarbageCollector;
} // namespac collector
} // namespace gc
class Closure;
class Thread;
class TimingLogger;
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 = MsToNs(kIsDebugBuild ? 50000 : 10000);
explicit ThreadList(uint64_t thread_suspend_timeout_ns);
~ThreadList();
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_);
void Resume(Thread* thread, bool for_debugger = false)
REQUIRES(!Locks::thread_suspend_count_lock_);
// 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, bool debug_suspension,
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, bool debug_suspension, 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_);
// Run a checkpoint on threads, running threads are not suspended but run the checkpoint inside
// of the suspend check. Returns how many checkpoints that are expected to run, including for
// already suspended threads for b/24191051. Run the callback, if non-null, inside the
// thread_list_lock critical section after determining the runnable/suspended states of the
// 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_);
size_t RunCheckpointOnRunnableThreads(Closure* checkpoint_function)
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)
REQUIRES(!Locks::mutator_lock_,
!Locks::thread_list_lock_,
!Locks::thread_suspend_count_lock_);
// Suspends all threads
void SuspendAllForDebugger()
REQUIRES(!Locks::mutator_lock_,
!Locks::thread_list_lock_,
!Locks::thread_suspend_count_lock_);
void SuspendSelfForDebugger()
REQUIRES(!Locks::thread_suspend_count_lock_);
// Resume all threads
void ResumeAllForDebugger()
REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_);
void UndoDebuggerSuspensions()
REQUIRES(!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_);
// 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_);
// Return a copy of the thread list.
std::list<Thread*> 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();
}
private:
uint32_t AllocThreadId(Thread* self);
void ReleaseThreadId(Thread* self, uint32_t id) REQUIRES(!Locks::allocated_thread_ids_lock_);
bool Contains(Thread* thread) REQUIRES(Locks::thread_list_lock_);
bool Contains(pid_t tid) REQUIRES(Locks::thread_list_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 WaitForOtherNonDaemonThreadsToExit()
REQUIRES(!Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_);
void SuspendAllInternal(Thread* self,
Thread* ignore1,
Thread* ignore2 = nullptr,
bool debug_suspend = false)
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<kMaxThreadId> allocated_ids_ GUARDED_BY(Locks::allocated_thread_ids_lock_);
// The actual list of all threads.
std::list<Thread*> 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_);
int debug_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<uint64_t> suspend_all_historam_ GUARDED_BY(Locks::mutator_lock_);
// Whether or not the current thread suspension is long.
bool long_suspend_;
// Thread suspension timeout in nanoseconds.
const uint64_t thread_suspend_timeout_ns_;
std::unique_ptr<Barrier> empty_checkpoint_barrier_;
friend class Thread;
DISALLOW_COPY_AND_ASSIGN(ThreadList);
};
// Helper for suspending all threads and
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_