v8threads.h revision a7e24c173cf37484693b9abb38e494fa7bd7baeb 
1// Copyright 2008 the V8 project authors. All rights reserved.
2// Redistribution and use in source and binary forms, with or without
3// modification, are permitted provided that the following conditions are
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5//
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7//       notice, this list of conditions and the following disclaimer.
8//     * Redistributions in binary form must reproduce the above
9//       copyright notice, this list of conditions and the following
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11//       with the distribution.
12//     * Neither the name of Google Inc. nor the names of its
13//       contributors may be used to endorse or promote products derived
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15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#ifndef V8_V8THREADS_H_
29#define V8_V8THREADS_H_
30
31namespace v8 {
32namespace internal {
33
34
35class ThreadState {
36 public:
37  // Iterate over in-use states.
38  static ThreadState* FirstInUse();
39  // Returns NULL after the last one.
40  ThreadState* Next();
41
42  enum List {FREE_LIST, IN_USE_LIST};
43
44  void LinkInto(List list);
45  void Unlink();
46
47  static ThreadState* GetFree();
48
49  // Id of thread.
50  void set_id(int id) { id_ = id; }
51  int id() { return id_; }
52
53  // Should the thread be terminated when it is restored?
54  bool terminate_on_restore() { return terminate_on_restore_; }
55  void set_terminate_on_restore(bool terminate_on_restore) {
56    terminate_on_restore_ = terminate_on_restore;
57  }
58
59  // Get data area for archiving a thread.
60  char* data() { return data_; }
61 private:
62  ThreadState();
63
64  void AllocateSpace();
65
66  int id_;
67  bool terminate_on_restore_;
68  char* data_;
69  ThreadState* next_;
70  ThreadState* previous_;
71
72  // In the following two lists there is always at least one object on the list.
73  // The first object is a flying anchor that is only there to simplify linking
74  // and unlinking.
75  // Head of linked list of free states.
76  static ThreadState* free_anchor_;
77  // Head of linked list of states in use.
78  static ThreadState* in_use_anchor_;
79};
80
81
82class ThreadManager : public AllStatic {
83 public:
84  static void Lock();
85  static void Unlock();
86
87  static void ArchiveThread();
88  static bool RestoreThread();
89  static void FreeThreadResources();
90  static bool IsArchived();
91
92  static void Iterate(ObjectVisitor* v);
93  static void MarkCompactPrologue(bool is_compacting);
94  static void MarkCompactEpilogue(bool is_compacting);
95  static bool IsLockedByCurrentThread() { return mutex_owner_.IsSelf(); }
96
97  static int CurrentId();
98  static void AssignId();
99  static bool HasId();
100
101  static void TerminateExecution(int thread_id);
102
103  static const int kInvalidId = -1;
104 private:
105  static void EagerlyArchiveThread();
106
107  static int last_id_;  // V8 threads are identified through an integer.
108  static Mutex* mutex_;
109  static ThreadHandle mutex_owner_;
110  static ThreadHandle lazily_archived_thread_;
111  static ThreadState* lazily_archived_thread_state_;
112};
113
114
115// The ContextSwitcher thread is used to schedule regular preemptions to
116// multiple running V8 threads. Generally it is necessary to call
117// StartPreemption if there is more than one thread running. If not, a single
118// JavaScript can take full control of V8 and not allow other threads to run.
119class ContextSwitcher: public Thread {
120 public:
121  // Set the preemption interval for the ContextSwitcher thread.
122  static void StartPreemption(int every_n_ms);
123
124  // Stop sending preemption requests to threads.
125  static void StopPreemption();
126
127  // Preempted thread needs to call back to the ContextSwitcher to acknowledge
128  // the handling of a preemption request.
129  static void PreemptionReceived();
130
131 private:
132  explicit ContextSwitcher(int every_n_ms);
133
134  void Run();
135
136  bool keep_going_;
137  int sleep_ms_;
138
139  static ContextSwitcher* singleton_;
140};
141
142} }  // namespace v8::internal
143
144#endif  // V8_V8THREADS_H_
145