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 58 private: 59 explicit ThreadState(ThreadManager* thread_manager); 60 61 void AllocateSpace(); 62 63 ThreadId id_; 64 bool terminate_on_restore_; 65 char* data_; 66 ThreadState* next_; 67 ThreadState* previous_; 68 69 ThreadManager* thread_manager_; 70 71 friend class ThreadManager; 72 }; 73 74 75 // Defined in isolate.h. 76 class ThreadLocalTop; 77 78 79 class ThreadVisitor { 80 public: 81 // ThreadLocalTop may be only available during this call. 82 virtual void VisitThread(Isolate* isolate, ThreadLocalTop* top) = 0; 83 84 protected: ~ThreadVisitor()85 virtual ~ThreadVisitor() {} 86 }; 87 88 89 class ThreadManager { 90 public: 91 void Lock(); 92 void Unlock(); 93 94 void ArchiveThread(); 95 bool RestoreThread(); 96 void FreeThreadResources(); 97 bool IsArchived(); 98 99 void Iterate(ObjectVisitor* v); 100 void IterateArchivedThreads(ThreadVisitor* v); IsLockedByCurrentThread()101 bool IsLockedByCurrentThread() { 102 return mutex_owner_.Equals(ThreadId::Current()); 103 } 104 105 ThreadId CurrentId(); 106 107 void TerminateExecution(ThreadId thread_id); 108 109 // Iterate over in-use states. 110 ThreadState* FirstThreadStateInUse(); 111 ThreadState* GetFreeThreadState(); 112 113 private: 114 ThreadManager(); 115 ~ThreadManager(); 116 117 void EagerlyArchiveThread(); 118 119 Mutex* mutex_; 120 ThreadId mutex_owner_; 121 ThreadId lazily_archived_thread_; 122 ThreadState* lazily_archived_thread_state_; 123 124 // In the following two lists there is always at least one object on the list. 125 // The first object is a flying anchor that is only there to simplify linking 126 // and unlinking. 127 // Head of linked list of free states. 128 ThreadState* free_anchor_; 129 // Head of linked list of states in use. 130 ThreadState* in_use_anchor_; 131 132 Isolate* isolate_; 133 134 friend class Isolate; 135 friend class ThreadState; 136 }; 137 138 139 // The ContextSwitcher thread is used to schedule regular preemptions to 140 // multiple running V8 threads. Generally it is necessary to call 141 // StartPreemption if there is more than one thread running. If not, a single 142 // JavaScript can take full control of V8 and not allow other threads to run. 143 class ContextSwitcher: public Thread { 144 public: 145 // Set the preemption interval for the ContextSwitcher thread. 146 static void StartPreemption(int every_n_ms); 147 148 // Stop sending preemption requests to threads. 149 static void StopPreemption(); 150 151 // Preempted thread needs to call back to the ContextSwitcher to acknowledge 152 // the handling of a preemption request. 153 static void PreemptionReceived(); 154 155 private: 156 ContextSwitcher(Isolate* isolate, int every_n_ms); 157 isolate()158 Isolate* isolate() const { return isolate_; } 159 160 void Run(); 161 162 bool keep_going_; 163 int sleep_ms_; 164 Isolate* isolate_; 165 }; 166 167 } } // namespace v8::internal 168 169 #endif // V8_V8THREADS_H_ 170