1 /*
   2  * Copyright (c) 2001, 2015, 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
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  24 
  25 #ifndef SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP
  26 #define SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP
  27 
  28 #include "gc/shared/concurrentGCThread.hpp"
  29 
  30 // The Concurrent Mark GC Thread (could be several in the future).
  31 // This is copied from the Concurrent Mark Sweep GC Thread
  32 // Still under construction.
  33 
  34 class ConcurrentMark;
  35 
  36 class ConcurrentMarkThread: public ConcurrentGCThread {
  37   friend class VMStructs;
  38 
  39   double _vtime_start;  // Initial virtual time.
  40   double _vtime_accum;  // Accumulated virtual time.
  41 
  42   double _vtime_mark_accum;
  43 
  44  public:
  45   virtual void run();
  46 
  47  private:
  48   ConcurrentMark*                  _cm;
  49   volatile bool                    _started;
  50   volatile bool                    _in_progress;
  51 
  52   void sleepBeforeNextCycle();
  53 
  54   static SurrogateLockerThread*         _slt;
  55 
  56  public:
  57   // Constructor
  58   ConcurrentMarkThread(ConcurrentMark* cm);
  59 
  60   static void makeSurrogateLockerThread(TRAPS);
  61   static SurrogateLockerThread* slt() { return _slt; }
  62 
  63   // Total virtual time so far.
  64   double vtime_accum();
  65   // Marking virtual time so far
  66   double vtime_mark_accum();
  67 
  68   ConcurrentMark* cm()     { return _cm; }
  69 
  70   void set_started()       { assert(!_in_progress, "cycle in progress"); _started = true;  }
  71   void clear_started()     { assert(_in_progress, "must be starting a cycle"); _started = false; }
  72   bool started()           { return _started;  }
  73 
  74   void set_in_progress()   { assert(_started, "must be starting a cycle"); _in_progress = true;  }
  75   void clear_in_progress() { assert(!_started, "must not be starting a new cycle"); _in_progress = false; }
  76   bool in_progress()       { return _in_progress;  }
  77 
  78   // This flag returns true from the moment a marking cycle is
  79   // initiated (during the initial-mark pause when started() is set)
  80   // to the moment when the cycle completes (just after the next
  81   // marking bitmap has been cleared and in_progress() is
  82   // cleared). While this flag is true we will not start another cycle
  83   // so that cycles do not overlap. We cannot use just in_progress()
  84   // as the CM thread might take some time to wake up before noticing
  85   // that started() is set and set in_progress().
  86   bool during_cycle()      { return started() || in_progress(); }
  87 
  88   // shutdown
  89   void stop();
  90 };
  91 
  92 #endif // SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP