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 // 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. set_id(int id)50 void set_id(int id) { id_ = id; } id()51 int id() { return id_; } 52 53 // Should the thread be terminated when it is restored? terminate_on_restore()54 bool terminate_on_restore() { return terminate_on_restore_; } set_terminate_on_restore(bool 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. data()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 82 class ThreadManager : public AllStatic { 83 public: 84 static void Lock(); 85 static void Unlock(); 86 87 static void ArchiveThread(); 88 static bool RestoreThread(); 89 static bool IsArchived(); 90 91 static void Iterate(ObjectVisitor* v); 92 static void MarkCompactPrologue(bool is_compacting); 93 static void MarkCompactEpilogue(bool is_compacting); IsLockedByCurrentThread()94 static bool IsLockedByCurrentThread() { return mutex_owner_.IsSelf(); } 95 96 static int CurrentId(); 97 static void AssignId(); 98 static bool HasId(); 99 100 static void TerminateExecution(int thread_id); 101 102 static const int kInvalidId = -1; 103 private: 104 static void EagerlyArchiveThread(); 105 106 static int last_id_; // V8 threads are identified through an integer. 107 static Mutex* mutex_; 108 static ThreadHandle mutex_owner_; 109 static ThreadHandle lazily_archived_thread_; 110 static ThreadState* lazily_archived_thread_state_; 111 }; 112 113 114 // The ContextSwitcher thread is used to schedule regular preemptions to 115 // multiple running V8 threads. Generally it is necessary to call 116 // StartPreemption if there is more than one thread running. If not, a single 117 // JavaScript can take full control of V8 and not allow other threads to run. 118 class ContextSwitcher: public Thread { 119 public: 120 // Set the preemption interval for the ContextSwitcher thread. 121 static void StartPreemption(int every_n_ms); 122 123 // Stop sending preemption requests to threads. 124 static void StopPreemption(); 125 126 // Preempted thread needs to call back to the ContextSwitcher to acknowledge 127 // the handling of a preemption request. 128 static void PreemptionReceived(); 129 130 private: 131 explicit ContextSwitcher(int every_n_ms); 132 133 void Run(); 134 135 bool keep_going_; 136 int sleep_ms_; 137 138 static ContextSwitcher* singleton_; 139 }; 140 141 } } // namespace v8::internal 142 143 #endif // V8_V8THREADS_H_ 144