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/mutex.h"
21 #include "gc_root.h"
22 #include "jni.h"
23 #include "object_callbacks.h"
24 
25 #include <bitset>
26 #include <list>
27 
28 namespace art {
29 class Closure;
30 class Thread;
31 class TimingLogger;
32 
33 class ThreadList {
34  public:
35   static const uint32_t kMaxThreadId = 0xFFFF;
36   static const uint32_t kInvalidThreadId = 0;
37   static const uint32_t kMainThreadId = 1;
38 
39   explicit ThreadList();
40   ~ThreadList();
41 
42   void DumpForSigQuit(std::ostream& os)
43       LOCKS_EXCLUDED(Locks::thread_list_lock_)
44       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
45   void DumpLocked(std::ostream& os)  // For thread suspend timeout dumps.
46       EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_)
47       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
48   pid_t GetLockOwner();  // For SignalCatcher.
49 
50   // Thread suspension support.
51   void ResumeAll()
52       UNLOCK_FUNCTION(Locks::mutator_lock_)
53       LOCKS_EXCLUDED(Locks::thread_list_lock_,
54                      Locks::thread_suspend_count_lock_);
55   void Resume(Thread* thread, bool for_debugger = false)
56       LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_);
57 
58   // Suspends all threads and gets exclusive access to the mutator_lock_.
59   void SuspendAll()
60       EXCLUSIVE_LOCK_FUNCTION(Locks::mutator_lock_)
61       LOCKS_EXCLUDED(Locks::thread_list_lock_,
62                      Locks::thread_suspend_count_lock_);
63 
64 
65   // Suspend a thread using a peer, typically used by the debugger. Returns the thread on success,
66   // else NULL. The peer is used to identify the thread to avoid races with the thread terminating.
67   // If the thread should be suspended then value of request_suspension should be true otherwise
68   // the routine will wait for a previous suspend request. If the suspension times out then *timeout
69   // is set to true.
70   Thread* SuspendThreadByPeer(jobject peer, bool request_suspension, bool debug_suspension,
71                               bool* timed_out)
72       EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_suspend_thread_lock_)
73       LOCKS_EXCLUDED(Locks::mutator_lock_,
74                      Locks::thread_list_lock_,
75                      Locks::thread_suspend_count_lock_);
76 
77   // Suspend a thread using its thread id, typically used by lock/monitor inflation. Returns the
78   // thread on success else NULL. The thread id is used to identify the thread to avoid races with
79   // the thread terminating. Note that as thread ids are recycled this may not suspend the expected
80   // thread, that may be terminating. If the suspension times out then *timeout is set to true.
81   Thread* SuspendThreadByThreadId(uint32_t thread_id, bool debug_suspension, bool* timed_out)
82       EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_suspend_thread_lock_)
83       LOCKS_EXCLUDED(Locks::mutator_lock_,
84                      Locks::thread_list_lock_,
85                      Locks::thread_suspend_count_lock_);
86 
87   // Find an already suspended thread (or self) by its id.
88   Thread* FindThreadByThreadId(uint32_t thin_lock_id);
89 
90   // Run a checkpoint on threads, running threads are not suspended but run the checkpoint inside
91   // of the suspend check. Returns how many checkpoints we should expect to run.
92   size_t RunCheckpoint(Closure* checkpoint_function)
93       LOCKS_EXCLUDED(Locks::thread_list_lock_,
94                      Locks::thread_suspend_count_lock_);
95 
96   size_t RunCheckpointOnRunnableThreads(Closure* checkpoint_function)
97       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::thread_suspend_count_lock_);
98 
99   // Suspends all threads
100   void SuspendAllForDebugger()
101       LOCKS_EXCLUDED(Locks::mutator_lock_,
102                      Locks::thread_list_lock_,
103                      Locks::thread_suspend_count_lock_);
104 
105   void SuspendSelfForDebugger()
106       LOCKS_EXCLUDED(Locks::thread_suspend_count_lock_);
107 
108   // Resume all threads
109   void ResumeAllForDebugger()
110       LOCKS_EXCLUDED(Locks::thread_list_lock_,
111                      Locks::thread_suspend_count_lock_);
112 
113   void UndoDebuggerSuspensions()
114       LOCKS_EXCLUDED(Locks::thread_list_lock_,
115                      Locks::thread_suspend_count_lock_);
116 
117   // Iterates over all the threads.
118   void ForEach(void (*callback)(Thread*, void*), void* context)
119       EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_);
120 
121   // Add/remove current thread from list.
122   void Register(Thread* self)
123       EXCLUSIVE_LOCKS_REQUIRED(Locks::runtime_shutdown_lock_)
124       LOCKS_EXCLUDED(Locks::mutator_lock_, Locks::thread_list_lock_);
125   void Unregister(Thread* self) LOCKS_EXCLUDED(Locks::mutator_lock_, Locks::thread_list_lock_);
126 
127   void VisitRoots(RootCallback* callback, void* arg) const
128       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
129 
130   // Return a copy of the thread list.
GetList()131   std::list<Thread*> GetList() EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_) {
132     return list_;
133   }
134 
135   void DumpNativeStacks(std::ostream& os)
136       LOCKS_EXCLUDED(Locks::thread_list_lock_);
137 
138  private:
139   uint32_t AllocThreadId(Thread* self);
140   void ReleaseThreadId(Thread* self, uint32_t id) LOCKS_EXCLUDED(Locks::allocated_thread_ids_lock_);
141 
142   bool Contains(Thread* thread) EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_);
143   bool Contains(pid_t tid) EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_list_lock_);
144 
145   void DumpUnattachedThreads(std::ostream& os)
146       LOCKS_EXCLUDED(Locks::thread_list_lock_);
147 
148   void SuspendAllDaemonThreads()
149       LOCKS_EXCLUDED(Locks::thread_list_lock_,
150                      Locks::thread_suspend_count_lock_);
151   void WaitForOtherNonDaemonThreadsToExit()
152       LOCKS_EXCLUDED(Locks::thread_list_lock_,
153                      Locks::thread_suspend_count_lock_);
154 
155   void AssertThreadsAreSuspended(Thread* self, Thread* ignore1, Thread* ignore2 = NULL)
156       LOCKS_EXCLUDED(Locks::thread_list_lock_,
157                      Locks::thread_suspend_count_lock_);
158 
159   std::bitset<kMaxThreadId> allocated_ids_ GUARDED_BY(Locks::allocated_thread_ids_lock_);
160 
161   // The actual list of all threads.
162   std::list<Thread*> list_ GUARDED_BY(Locks::thread_list_lock_);
163 
164   // Ongoing suspend all requests, used to ensure threads added to list_ respect SuspendAll.
165   int suspend_all_count_ GUARDED_BY(Locks::thread_suspend_count_lock_);
166   int debug_suspend_all_count_ GUARDED_BY(Locks::thread_suspend_count_lock_);
167 
168   // Signaled when threads terminate. Used to determine when all non-daemons have terminated.
169   ConditionVariable thread_exit_cond_ GUARDED_BY(Locks::thread_list_lock_);
170 
171   friend class Thread;
172 
173   DISALLOW_COPY_AND_ASSIGN(ThreadList);
174 };
175 
176 }  // namespace art
177 
178 #endif  // ART_RUNTIME_THREAD_LIST_H_
179