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 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