thread_list.h revision 77be6635f9b07a8a794924c5fb9b071949776a6d 
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_THREAD_LIST_H_
18#define ART_RUNTIME_THREAD_LIST_H_
19
20#include "base/histogram.h"
21#include "base/mutex.h"
22#include "gc_root.h"
23#include "jni.h"
24#include "object_callbacks.h"
25
26#include <bitset>
27#include <list>
28
29namespace art {
30namespace gc {
31  namespace collector {
32    class GarbageCollector;
33  }  // namespac collector
34}  // namespace gc
35class Closure;
36class Thread;
37class TimingLogger;
38
39class ThreadList {
40 public:
41  static const uint32_t kMaxThreadId = 0xFFFF;
42  static const uint32_t kInvalidThreadId = 0;
43  static const uint32_t kMainThreadId = 1;
44
45  explicit ThreadList();
46  ~ThreadList();
47
48  void DumpForSigQuit(std::ostream& os)
49      LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::mutator_lock_);
50  // For thread suspend timeout dumps.
51  void Dump(std::ostream& os)
52      LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::thread_suspend_count_lock_);
53  pid_t GetLockOwner();  // For SignalCatcher.
54
55  // Thread suspension support.
56  void ResumeAll()
57      UNLOCK_FUNCTION(Locks::mutator_lock_)
58      LOCKS_EXCLUDED(Locks::thread_list_lock_,
59                     Locks::thread_suspend_count_lock_);
60  void Resume(Thread* thread, bool for_debugger = false)
61      LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_);
62
63  // Suspends all threads and gets exclusive access to the mutator_lock_.
64  // If long suspend is true, then other people who try to suspend will never timeout. Long suspend
65  // is currenly used for hprof since large heaps take a long time.
66  void SuspendAll(const char* cause, bool long_suspend = false)
67      EXCLUSIVE_LOCK_FUNCTION(Locks::mutator_lock_)
68      LOCKS_EXCLUDED(Locks::thread_list_lock_,
69                     Locks::thread_suspend_count_lock_);
70
71
72  // Suspend a thread using a peer, typically used by the debugger. Returns the thread on success,
73  // else null. The peer is used to identify the thread to avoid races with the thread terminating.
74  // If the thread should be suspended then value of request_suspension should be true otherwise
75  // the routine will wait for a previous suspend request. If the suspension times out then *timeout
76  // is set to true.
77  Thread* SuspendThreadByPeer(jobject peer, bool request_suspension, bool debug_suspension,
78                              bool* timed_out)
79      LOCKS_EXCLUDED(Locks::mutator_lock_,
80                     Locks::thread_list_lock_,
81                     Locks::thread_suspend_count_lock_);
82
83  // Suspend a thread using its thread id, typically used by lock/monitor inflation. Returns the
84  // thread on success else null. The thread id is used to identify the thread to avoid races with
85  // the thread terminating. Note that as thread ids are recycled this may not suspend the expected
86  // thread, that may be terminating. If the suspension times out then *timeout is set to true.
87  Thread* SuspendThreadByThreadId(uint32_t thread_id, bool debug_suspension, bool* timed_out)
88      LOCKS_EXCLUDED(Locks::mutator_lock_,
89                     Locks::thread_list_lock_,
90                     Locks::thread_suspend_count_lock_);
91
92  // Find an already suspended thread (or self) by its id.
93  Thread* FindThreadByThreadId(uint32_t thin_lock_id);
94
95  // Run a checkpoint on threads, running threads are not suspended but run the checkpoint inside
96  // of the suspend check. Returns how many checkpoints we should expect to run.
97  size_t RunCheckpoint(Closure* checkpoint_function)
98      LOCKS_EXCLUDED(Locks::thread_list_lock_,
99                     Locks::thread_suspend_count_lock_);
100
101  size_t RunCheckpointOnRunnableThreads(Closure* checkpoint_function)
102  LOCKS_EXCLUDED(Locks::thread_list_lock_,
103                 Locks::thread_suspend_count_lock_);
104
105  // Flip thread roots from from-space refs to to-space refs. Used by
106  // the concurrent copying collector.
107  size_t FlipThreadRoots(Closure* thread_flip_visitor, Closure* flip_callback,
108                         gc::collector::GarbageCollector* collector)
109      LOCKS_EXCLUDED(Locks::mutator_lock_,
110                     Locks::thread_list_lock_,
111                     Locks::thread_suspend_count_lock_);
112
113  // Suspends all threads
114  void SuspendAllForDebugger()
115      LOCKS_EXCLUDED(Locks::mutator_lock_,
116                     Locks::thread_list_lock_,
117                     Locks::thread_suspend_count_lock_);
118
119  void SuspendSelfForDebugger()
120      LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_);
121
122  // Resume all threads
123  void ResumeAllForDebugger()
124      LOCKS_EXCLUDED(Locks::thread_list_lock_,
125                     Locks::thread_suspend_count_lock_);
126
127  void UndoDebuggerSuspensions()
128      LOCKS_EXCLUDED(Locks::thread_list_lock_,
129                     Locks::thread_suspend_count_lock_);
130
131  // Iterates over all the threads.
132  void ForEach(void (*callback)(Thread*, void*), void* context)
133      EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_);
134
135  // Add/remove current thread from list.
136  void Register(Thread* self)
137      EXCLUSIVE_LOCKS_REQUIRED(Locks::runtime_shutdown_lock_)
138      LOCKS_EXCLUDED(Locks::mutator_lock_, Locks::thread_list_lock_);
139  void Unregister(Thread* self) LOCKS_EXCLUDED(Locks::mutator_lock_, Locks::thread_list_lock_);
140
141  void VisitRoots(RootVisitor* visitor) const
142      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
143
144  // Return a copy of the thread list.
145  std::list<Thread*> GetList() EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_) {
146    return list_;
147  }
148
149  void DumpNativeStacks(std::ostream& os)
150      LOCKS_EXCLUDED(Locks::thread_list_lock_);
151
152 private:
153  uint32_t AllocThreadId(Thread* self);
154  void ReleaseThreadId(Thread* self, uint32_t id) LOCKS_EXCLUDED(Locks::allocated_thread_ids_lock_);
155
156  bool Contains(Thread* thread) EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_);
157  bool Contains(pid_t tid) EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_);
158
159  void DumpUnattachedThreads(std::ostream& os)
160      LOCKS_EXCLUDED(Locks::thread_list_lock_);
161
162  void SuspendAllDaemonThreads()
163      LOCKS_EXCLUDED(Locks::thread_list_lock_,
164                     Locks::thread_suspend_count_lock_);
165  void WaitForOtherNonDaemonThreadsToExit()
166      LOCKS_EXCLUDED(Locks::thread_list_lock_,
167                     Locks::thread_suspend_count_lock_);
168
169  void AssertThreadsAreSuspended(Thread* self, Thread* ignore1, Thread* ignore2 = nullptr)
170      LOCKS_EXCLUDED(Locks::thread_list_lock_,
171                     Locks::thread_suspend_count_lock_);
172
173  std::bitset<kMaxThreadId> allocated_ids_ GUARDED_BY(Locks::allocated_thread_ids_lock_);
174
175  // The actual list of all threads.
176  std::list<Thread*> list_ GUARDED_BY(Locks::thread_list_lock_);
177
178  // Ongoing suspend all requests, used to ensure threads added to list_ respect SuspendAll.
179  int suspend_all_count_ GUARDED_BY(Locks::thread_suspend_count_lock_);
180  int debug_suspend_all_count_ GUARDED_BY(Locks::thread_suspend_count_lock_);
181
182  // Number of threads unregistering, ~ThreadList blocks until this hits 0.
183  int unregistering_count_ GUARDED_BY(Locks::thread_list_lock_);
184
185  // Thread suspend time histogram. Only modified when all the threads are suspended, so guarding
186  // by mutator lock ensures no thread can read when another thread is modifying it.
187  Histogram<uint64_t> suspend_all_historam_ GUARDED_BY(Locks::mutator_lock_);
188
189  // Whether or not the current thread suspension is long.
190  bool long_suspend_;
191
192  friend class Thread;
193
194  DISALLOW_COPY_AND_ASSIGN(ThreadList);
195};
196
197}  // namespace art
198
199#endif  // ART_RUNTIME_THREAD_LIST_H_
200