1 /*
   2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINETHREAD_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINETHREAD_HPP
  27 
  28 #include "gc_implementation/shared/concurrentGCThread.hpp"
  29 
  30 // Forward Decl.
  31 class ConcurrentG1Refine;
  32 
  33 // The G1 Concurrent Refinement Thread (could be several in the future).
  34 
  35 class ConcurrentG1RefineThread: public ConcurrentGCThread {
  36   friend class VMStructs;
  37   friend class G1CollectedHeap;
  38 
  39   double _vtime_start;  // Initial virtual time.
  40   double _vtime_accum;  // Initial virtual time.
  41   int _worker_id;
  42   int _worker_id_offset;
  43 
  44   // The refinement threads collection is linked list. A predecessor can activate a successor
  45   // when the number of the rset update buffer crosses a certain threshold. A successor
  46   // would self-deactivate when the number of the buffers falls below the threshold.
  47   bool _active;
  48   ConcurrentG1RefineThread* _next;
  49   Monitor* _monitor;
  50   ConcurrentG1Refine* _cg1r;
  51 
  52   int _thread_threshold_step;
  53   // This thread activation threshold
  54   int _threshold;
  55   // This thread deactivation threshold
  56   int _deactivation_threshold;
  57 
  58   void sample_young_list_rs_lengths();
  59   void run_young_rs_sampling();
  60   void wait_for_completed_buffers();
  61 
  62   void set_active(bool x) { _active = x; }
  63   bool is_active();
  64   void activate();
  65   void deactivate();
  66 
  67   // For use by G1CollectedHeap, which is a friend.
  68   static SuspendibleThreadSet* sts() { return &_sts; }
  69 
  70 public:
  71   virtual void run();
  72   // Constructor
  73   ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread* next,
  74                            int worker_id_offset, int worker_id);
  75 
  76   void initialize();
  77 
  78   // Printing
  79   void print() const;
  80   void print_on(outputStream* st) const;
  81 
  82   // Total virtual time so far.
  83   double vtime_accum() { return _vtime_accum; }
  84 
  85   ConcurrentG1Refine* cg1r() { return _cg1r;     }
  86 
  87   // Yield for GC
  88   void yield();
  89   // shutdown
  90   void stop();
  91 };
  92 
  93 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINETHREAD_HPP