1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
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  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).
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  24 
  25 #ifndef SHARE_GC_G1_G1CONCURRENTREFINETHREAD_HPP
  26 #define SHARE_GC_G1_G1CONCURRENTREFINETHREAD_HPP
  27 
  28 #include "gc/shared/concurrentGCThread.hpp"
  29 #include "utilities/ticks.hpp"
  30 
  31 // Forward Decl.
  32 class G1ConcurrentRefine;
  33 
  34 // One or more G1 Concurrent Refinement Threads may be active if concurrent
  35 // refinement is in progress.
  36 class G1ConcurrentRefineThread: public ConcurrentGCThread {
  37   friend class VMStructs;
  38   friend class G1CollectedHeap;
  39 
  40   double _vtime_start;  // Initial virtual time.
  41   double _vtime_accum;  // Accumulated virtual time.
  42 
  43   Tickspan _total_refinement_time;
  44   size_t _total_refined_cards;
  45 
  46   uint _worker_id;
  47 
  48   // _notifier and _should_notify form a single-reader / multi-writer
  49   // notification mechanism.  The owning concurrent refinement thread is the
  50   // single reader. The writers are (other) threads that call activate() on
  51   // the thread.  The i-th concurrent refinement thread is responsible for
  52   // activating thread i+1 if the number of buffers in the queue exceeds a
  53   // threshold for that i+1th thread.  The 0th (primary) thread is activated
  54   // by threads that add cards to the dirty card queue set when the primary
  55   // thread's threshold is exceeded.  activate() is also used to wake up the
  56   // threads during termination, so even the non-primary thread case is
  57   // multi-writer.
  58   Semaphore* _notifier;
  59   volatile bool _should_notify;
  60 
  61   // Called when no refinement work found for this thread.
  62   // Returns true if should deactivate.
  63   bool maybe_deactivate(bool more_work);
  64 
  65   G1ConcurrentRefine* _cr;
  66 
  67   void wait_for_completed_buffers();
  68 
  69   virtual void run_service();
  70   virtual void stop_service();
  71 
  72 public:
  73   G1ConcurrentRefineThread(G1ConcurrentRefine* cg1r, uint worker_id);
  74 
  75   // Activate this thread.
  76   void activate();
  77 
  78   Tickspan total_refinement_time() const { return _total_refinement_time; }
  79   size_t total_refined_cards() const { return _total_refined_cards; }
  80 
  81   // Total virtual time so far.
  82   double vtime_accum() { return _vtime_accum; }
  83 };
  84 
  85 #endif // SHARE_GC_G1_G1CONCURRENTREFINETHREAD_HPP