1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   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.
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   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  *
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  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 triggers the parallel G1CMConcurrentMarkingTasks
  31 // as well as handling various marking cleanup.
  32 
  33 class G1ConcurrentMark;
  34 class G1Policy;
  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   double _vtime_mark_accum;
  42 
  43   G1ConcurrentMark*                _cm;
  44 
  45   enum State {
  46     Idle,
  47     Started,
  48     InProgress
  49   };
  50 
  51   volatile State _state;
  52 
  53   void sleepBeforeNextCycle();
  54   void delay_to_keep_mmu(G1Policy* g1_policy, bool remark);
  55 
  56   void run_service();
  57   void stop_service();
  58 
  59  public:
  60   // Constructor
  61   ConcurrentMarkThread(G1ConcurrentMark* cm);
  62 
  63   // Total virtual time so far for this thread and concurrent marking tasks.
  64   double vtime_accum();
  65   // Marking virtual time so far this thread and concurrent marking tasks.
  66   double vtime_mark_accum();
  67 
  68   G1ConcurrentMark* cm()   { return _cm; }
  69 
  70   void set_idle()          { assert(_state != Started, "must not be starting a new cycle"); _state = Idle; }
  71   bool idle()              { return _state == Idle; }
  72   void set_started()       { assert(_state == Idle, "cycle in progress"); _state = Started; }
  73   bool started()           { return _state == Started; }
  74   void set_in_progress()   { assert(_state == Started, "must be starting a cycle"); _state = InProgress; }
  75   bool in_progress()       { return _state == InProgress; }
  76 
  77   // Returns true from the moment a marking cycle is
  78   // initiated (during the initial-mark pause when started() is set)
  79   // to the moment when the cycle completes (just after the next
  80   // marking bitmap has been cleared and in_progress() is
  81   // cleared). While during_cycle() is true we will not start another cycle
  82   // so that cycles do not overlap. We cannot use just in_progress()
  83   // as the CM thread might take some time to wake up before noticing
  84   // that started() is set and set in_progress().
  85   bool during_cycle()      { return !idle(); }
  86 };
  87 
  88 #endif // SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP