1 /*
   2  * Copyright (c) 2001, 2019, 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.
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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  *
  15  * You should have received a copy of the GNU General Public License version
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  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_GC_G1_G1CONCURRENTMARKTHREAD_HPP
  26 #define SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP
  27 
  28 #include "gc/shared/concurrentGCPhaseManager.hpp"
  29 #include "gc/shared/concurrentGCThread.hpp"
  30 
  31 class G1ConcurrentMark;
  32 class G1Policy;
  33 
  34 // The concurrent mark thread triggers the various steps of the concurrent marking
  35 // cycle, including various marking cleanup.
  36 class G1ConcurrentMarkThread: 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   // WhiteBox testing support.
  54   ConcurrentGCPhaseManager::Stack _phase_manager_stack;
  55 
  56   void sleep_before_next_cycle();
  57   // Delay marking to meet MMU.
  58   void delay_to_keep_mmu(G1Policy* g1_policy, bool remark);
  59   double mmu_sleep_time(G1Policy* g1_policy, bool remark);
  60 
  61   void run_service();
  62   void stop_service();
  63 
  64  public:
  65   // Constructor
  66   G1ConcurrentMarkThread(G1ConcurrentMark* cm);
  67 
  68   // Total virtual time so far for this thread and concurrent marking tasks.
  69   double vtime_accum();
  70   // Marking virtual time so far this thread and concurrent marking tasks.
  71   double vtime_mark_accum();
  72 
  73   G1ConcurrentMark* cm()   { return _cm; }
  74 
  75   void set_idle()          { assert(_state != Started, "must not be starting a new cycle"); _state = Idle; }
  76   bool idle()              { return _state == Idle; }
  77   void set_started()       { assert(_state == Idle, "cycle in progress"); _state = Started; }
  78   bool started()           { return _state == Started; }
  79   void set_in_progress()   { assert(_state == Started, "must be starting a cycle"); _state = InProgress; }
  80   bool in_progress()       { return _state == InProgress; }
  81 
  82   // Returns true from the moment a marking cycle is
  83   // initiated (during the initial-mark pause when started() is set)
  84   // to the moment when the cycle completes (just after the next
  85   // marking bitmap has been cleared and in_progress() is
  86   // cleared). While during_cycle() is true we will not start another cycle
  87   // so that cycles do not overlap. We cannot use just in_progress()
  88   // as the CM thread might take some time to wake up before noticing
  89   // that started() is set and set in_progress().
  90   bool during_cycle()      { return !idle(); }
  91 
  92   // WhiteBox testing support.
  93   bool request_concurrent_phase(const char* phase);
  94 
  95   ConcurrentGCPhaseManager::Stack* phase_manager_stack() {
  96     return &_phase_manager_stack;
  97   }
  98 };
  99 
 100 #endif // SHARE_GC_G1_G1CONCURRENTMARKTHREAD_HPP