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 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 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 10 // disclaimer in the documentation and/or other materials provided 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 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 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 31 namespace v8 { 32 namespace internal { 33 34 35 class ThreadState { 36 public: 37 // Returns NULL after the last one. 38 ThreadState* Next(); 39 40 enum List {FREE_LIST, IN_USE_LIST}; 41 42 void LinkInto(List list); 43 void Unlink(); 44 45 // Id of thread. set_id(ThreadId id)46 void set_id(ThreadId id) { id_ = id; } id()47 ThreadId id() { return id_; } 48 49 // Should the thread be terminated when it is restored? terminate_on_restore()50 bool terminate_on_restore() { return terminate_on_restore_; } set_terminate_on_restore(bool terminate_on_restore)51 void set_terminate_on_restore(bool terminate_on_restore) { 52 terminate_on_restore_ = terminate_on_restore; 53 } 54 55 // Get data area for archiving a thread. data()56 char* data() { return data_; } 57 private: 58 explicit ThreadState(ThreadManager* thread_manager); 59 60 void AllocateSpace(); 61 62 ThreadId id_; 63 bool terminate_on_restore_; 64 char* data_; 65 ThreadState* next_; 66 ThreadState* previous_; 67 68 ThreadManager* thread_manager_; 69 70 friend class ThreadManager; 71 }; 72 73 74 // Defined in top.h 75 class ThreadLocalTop; 76 77 78 class ThreadVisitor { 79 public: 80 // ThreadLocalTop may be only available during this call. 81 virtual void VisitThread(Isolate* isolate, ThreadLocalTop* top) = 0; 82 83 protected: ~ThreadVisitor()84 virtual ~ThreadVisitor() {} 85 }; 86 87 88 class ThreadManager { 89 public: 90 void Lock(); 91 void Unlock(); 92 93 void ArchiveThread(); 94 bool RestoreThread(); 95 void FreeThreadResources(); 96 bool IsArchived(); 97 98 void Iterate(ObjectVisitor* v); 99 void IterateArchivedThreads(ThreadVisitor* v); IsLockedByCurrentThread()100 bool IsLockedByCurrentThread() { 101 return mutex_owner_.Equals(ThreadId::Current()); 102 } 103 104 ThreadId CurrentId(); 105 106 void TerminateExecution(ThreadId thread_id); 107 108 // Iterate over in-use states. 109 ThreadState* FirstThreadStateInUse(); 110 ThreadState* GetFreeThreadState(); 111 112 private: 113 ThreadManager(); 114 ~ThreadManager(); 115 116 void EagerlyArchiveThread(); 117 118 Mutex* mutex_; 119 ThreadId mutex_owner_; 120 ThreadId lazily_archived_thread_; 121 ThreadState* lazily_archived_thread_state_; 122 123 // In the following two lists there is always at least one object on the list. 124 // The first object is a flying anchor that is only there to simplify linking 125 // and unlinking. 126 // Head of linked list of free states. 127 ThreadState* free_anchor_; 128 // Head of linked list of states in use. 129 ThreadState* in_use_anchor_; 130 131 Isolate* isolate_; 132 133 friend class Isolate; 134 friend class ThreadState; 135 }; 136 137 138 // The ContextSwitcher thread is used to schedule regular preemptions to 139 // multiple running V8 threads. Generally it is necessary to call 140 // StartPreemption if there is more than one thread running. If not, a single 141 // JavaScript can take full control of V8 and not allow other threads to run. 142 class ContextSwitcher: public Thread { 143 public: 144 // Set the preemption interval for the ContextSwitcher thread. 145 static void StartPreemption(int every_n_ms); 146 147 // Stop sending preemption requests to threads. 148 static void StopPreemption(); 149 150 // Preempted thread needs to call back to the ContextSwitcher to acknowledge 151 // the handling of a preemption request. 152 static void PreemptionReceived(); 153 154 private: 155 explicit ContextSwitcher(Isolate* isolate, int every_n_ms); 156 157 void Run(); 158 159 bool keep_going_; 160 int sleep_ms_; 161 }; 162 163 } } // namespace v8::internal 164 165 #endif // V8_V8THREADS_H_ 166