1 /*
   2  * Copyright (c) 2001, 2016, 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 triggers the parallel G1CMConcurrentMarkingTasks
  31 // as well as handling various marking cleanup.
  32 
  33 class G1ConcurrentMark;
  34 class G1CollectorPolicy;
  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   G1ConcurrentMark*                _cm;
  49 
  50   enum State {
  51     Idle,
  52     Started,
  53     InProgress
  54   };
  55 
  56   volatile State _state;
  57 
  58   void sleepBeforeNextCycle();
  59   void delay_to_keep_mmu(G1CollectorPolicy* g1_policy, bool remark);
  60 
  61   void run_service();
  62   void stop_service();
  63 
  64   static SurrogateLockerThread*         _slt;
  65 
  66  public:
  67   // Constructor
  68   ConcurrentMarkThread(G1ConcurrentMark* cm);
  69 
  70   static void makeSurrogateLockerThread(TRAPS);
  71   static SurrogateLockerThread* slt() { return _slt; }
  72 
  73   // Total virtual time so far for this thread and concurrent marking tasks.
  74   double vtime_accum();
  75   // Marking virtual time so far this thread and concurrent marking tasks.
  76   double vtime_mark_accum();
  77 
  78   G1ConcurrentMark* cm()   { return _cm; }
  79 
  80   void set_idle()          { assert(_state != Started, "must not be starting a new cycle"); _state = Idle; }
  81   bool idle()              { return _state == Idle; }
  82   void set_started()       { assert(_state == Idle, "cycle in progress"); _state = Started; }
  83   bool started()           { return _state == Started; }
  84   void set_in_progress()   { assert(_state == Started, "must be starting a cycle"); _state = InProgress; }
  85   bool in_progress()       { return _state == InProgress; }
  86 
  87   // Returns true from the moment a marking cycle is
  88   // initiated (during the initial-mark pause when started() is set)
  89   // to the moment when the cycle completes (just after the next
  90   // marking bitmap has been cleared and in_progress() is
  91   // cleared). While during_cycle() is true we will not start another cycle
  92   // so that cycles do not overlap. We cannot use just in_progress()
  93   // as the CM thread might take some time to wake up before noticing
  94   // that started() is set and set in_progress().
  95   bool during_cycle()      { return !idle(); }
  96 
  97   // shutdown
  98   void stop();
  99 };
 100 
 101 #endif // SHARE_VM_GC_G1_CONCURRENTMARKTHREAD_HPP