src/share/vm/gc/shared/workgroup.hpp

rev 11036 : 6858051: Create GC worker threads dynamically
Reviewed-by:

*** 110,132 ****
--- 110,139 ----
    AbstractGangWorker** _workers;
    // The count of the number of workers in the gang.
    uint _total_workers;
    // The currently active workers in this gang.
    uint _active_workers;
+   // The count of created workers in the gang.
+   uint _created_workers;
    // Printing support.
    const char* _name;
  
   private:
    // Initialize only instance data.
    const bool _are_GC_task_threads;
    const bool _are_ConcurrentGC_threads;
  
+   void set_thread(uint worker_id, AbstractGangWorker* worker) {
+     _workers[worker_id] = worker;
+   }
+ 
   public:
    AbstractWorkGang(const char* name, uint workers, bool are_GC_task_threads, bool are_ConcurrentGC_threads) :
        _name(name),
        _total_workers(workers),
        _active_workers(UseDynamicNumberOfGCThreads ? 1U : workers),
+       _created_workers(0),
        _are_GC_task_threads(are_GC_task_threads),
        _are_ConcurrentGC_threads(are_ConcurrentGC_threads)
    { }
  
    // Initialize workers in the gang.  Return true if initialization succeeded.
*** 135,167 ****
    bool are_GC_task_threads()      const { return _are_GC_task_threads; }
    bool are_ConcurrentGC_threads() const { return _are_ConcurrentGC_threads; }
  
    uint total_workers() const { return _total_workers; }
  
    virtual uint active_workers() const {
      assert(_active_workers <= _total_workers,
             "_active_workers: %u > _total_workers: %u", _active_workers, _total_workers);
      assert(UseDynamicNumberOfGCThreads || _active_workers == _total_workers,
             "Unless dynamic should use total workers");
      return _active_workers;
    }
    void set_active_workers(uint v) {
      assert(v <= _total_workers,
             "Trying to set more workers active than there are");
      _active_workers = MIN2(v, _total_workers);
      assert(v != 0, "Trying to set active workers to 0");
-     _active_workers = MAX2(1U, _active_workers);
      assert(UseDynamicNumberOfGCThreads || _active_workers == _total_workers,
             "Unless dynamic should use total workers");
      log_info(gc, task)("GC Workers: using %d out of %d", _active_workers, _total_workers);
    }
  
    // Return the Ith worker.
    AbstractGangWorker* worker(uint i) const;
  
    void threads_do(ThreadClosure* tc) const;
  
    // Debugging.
    const char* name() const { return _name; }
  
    // Printing
    void print_worker_threads_on(outputStream *st) const;
--- 142,185 ----
    bool are_GC_task_threads()      const { return _are_GC_task_threads; }
    bool are_ConcurrentGC_threads() const { return _are_ConcurrentGC_threads; }
  
    uint total_workers() const { return _total_workers; }
  
+   uint created_workers() const {
+     return _created_workers;
+   }
+ 
    virtual uint active_workers() const {
      assert(_active_workers <= _total_workers,
             "_active_workers: %u > _total_workers: %u", _active_workers, _total_workers);
      assert(UseDynamicNumberOfGCThreads || _active_workers == _total_workers,
             "Unless dynamic should use total workers");
      return _active_workers;
    }
+ 
    void set_active_workers(uint v) {
      assert(v <= _total_workers,
             "Trying to set more workers active than there are");
      _active_workers = MIN2(v, _total_workers);
+     add_workers(false /* exit_on_failure */);
      assert(v != 0, "Trying to set active workers to 0");
      assert(UseDynamicNumberOfGCThreads || _active_workers == _total_workers,
             "Unless dynamic should use total workers");
      log_info(gc, task)("GC Workers: using %d out of %d", _active_workers, _total_workers);
    }
  
+   // Add GC workers as needed.
+   bool add_workers(bool initializing);
+ 
    // Return the Ith worker.
    AbstractGangWorker* worker(uint i) const;
  
    void threads_do(ThreadClosure* tc) const;
  
+   // Create a GC worker and install it into the work gang.
+   virtual AbstractGangWorker* install_worker(uint which);
+ 
    // Debugging.
    const char* name() const { return _name; }
  
    // Printing
    void print_worker_threads_on(outputStream *st) const;