Home | History | Annotate | Download | only in src 
      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.
     46   void set_id(ThreadId id) { id_ = id; }
     47   ThreadId id() { return id_; }
     48 
     49   // Should the thread be terminated when it is restored?
     50   bool terminate_on_restore() { return 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.
     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:
     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);
    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