Line data    Source code

       1             : // Copyright 2012 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_V8THREADS_H_
       6             : #define V8_V8THREADS_H_
       7             : 
       8             : #include <atomic>
       9             : 
      10             : #include "src/isolate.h"
      11             : 
      12             : namespace v8 {
      13             : namespace internal {
      14             : 
      15             : class RootVisitor;
      16             : class ThreadLocalTop;
      17             : 
      18             : class ThreadState {
      19             :  public:
      20             :   // Returns nullptr after the last one.
      21             :   ThreadState* Next();
      22             : 
      23             :   enum List {FREE_LIST, IN_USE_LIST};
      24             : 
      25             :   void LinkInto(List list);
      26             :   void Unlink();
      27             : 
      28             :   // Id of thread.
      29       68770 :   void set_id(ThreadId id) { id_ = id; }
      30             :   ThreadId id() { return id_; }
      31             : 
      32             :   // Should the thread be terminated when it is restored?
      33             :   bool terminate_on_restore() { return terminate_on_restore_; }
      34             :   void set_terminate_on_restore(bool terminate_on_restore) {
      35           0 :     terminate_on_restore_ = terminate_on_restore;
      36             :   }
      37             : 
      38             :   // Get data area for archiving a thread.
      39             :   char* data() { return data_; }
      40             : 
      41             :  private:
      42             :   explicit ThreadState(ThreadManager* thread_manager);
      43             :   ~ThreadState();
      44             : 
      45             :   void AllocateSpace();
      46             : 
      47             :   ThreadId id_;
      48             :   bool terminate_on_restore_;
      49             :   char* data_;
      50             :   ThreadState* next_;
      51             :   ThreadState* previous_;
      52             : 
      53             :   ThreadManager* thread_manager_;
      54             : 
      55             :   friend class ThreadManager;
      56             : };
      57             : 
      58       81461 : class ThreadVisitor {
      59             :  public:
      60             :   // ThreadLocalTop may be only available during this call.
      61             :   virtual void VisitThread(Isolate* isolate, ThreadLocalTop* top) = 0;
      62             : 
      63             :  protected:
      64       81461 :   virtual ~ThreadVisitor() = default;
      65             : };
      66             : 
      67             : class ThreadManager {
      68             :  public:
      69             :   void Lock();
      70             :   void Unlock();
      71             : 
      72             :   void InitThread(const ExecutionAccess&);
      73             :   void ArchiveThread();
      74             :   bool RestoreThread();
      75             :   void FreeThreadResources();
      76             :   bool IsArchived();
      77             : 
      78             :   void Iterate(RootVisitor* v);
      79             :   void IterateArchivedThreads(ThreadVisitor* v);
      80             :   bool IsLockedByCurrentThread() const {
      81             :     return mutex_owner_.load(std::memory_order_relaxed) == ThreadId::Current();
      82             :   }
      83             : 
      84             :   ThreadId CurrentId();
      85             : 
      86             :   void TerminateExecution(ThreadId thread_id);
      87             : 
      88             :   // Iterate over in-use states.
      89             :   ThreadState* FirstThreadStateInUse();
      90             :   ThreadState* GetFreeThreadState();
      91             : 
      92             :  private:
      93             :   explicit ThreadManager(Isolate* isolate);
      94             :   ~ThreadManager();
      95             : 
      96             :   void DeleteThreadStateList(ThreadState* anchor);
      97             : 
      98             :   void EagerlyArchiveThread();
      99             : 
     100             :   base::Mutex mutex_;
     101             :   // {ThreadId} must be trivially copyable to be stored in {std::atomic}.
     102             :   ASSERT_TRIVIALLY_COPYABLE(i::ThreadId);
     103             :   std::atomic<ThreadId> mutex_owner_;
     104             :   ThreadId lazily_archived_thread_;
     105             :   ThreadState* lazily_archived_thread_state_;
     106             : 
     107             :   // In the following two lists there is always at least one object on the list.
     108             :   // The first object is a flying anchor that is only there to simplify linking
     109             :   // and unlinking.
     110             :   // Head of linked list of free states.
     111             :   ThreadState* free_anchor_;
     112             :   // Head of linked list of states in use.
     113             :   ThreadState* in_use_anchor_;
     114             : 
     115             :   Isolate* isolate_;
     116             : 
     117             :   friend class Isolate;
     118             :   friend class ThreadState;
     119             : };
     120             : 
     121             : 
     122             : }  // namespace internal
     123             : }  // namespace v8
     124             : 
     125             : #endif  // V8_V8THREADS_H_