1 /*
   2  * Copyright (c) 2001, 2013, 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
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP
  27 
  28 #include "gc_implementation/g1/g1HotCardCache.hpp"
  29 #include "memory/allocation.hpp"
  30 #include "runtime/thread.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 
  33 // Forward decl
  34 class ConcurrentG1RefineThread;
  35 class G1CollectedHeap;
  36 class G1HotCardCache;
  37 class G1RemSet;
  38 
  39 class ConcurrentG1Refine: public CHeapObj<mtGC> {
  40   ConcurrentG1RefineThread** _threads;
  41   int _n_threads;
  42   int _n_worker_threads;
  43  /*
  44   * The value of the update buffer queue length falls into one of 3 zones:
  45   * green, yellow, red. If the value is in [0, green) nothing is
  46   * done, the buffers are left unprocessed to enable the caching effect of the
  47   * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement
  48   * threads are gradually activated. In [yellow, red) all threads are
  49   * running. If the length becomes red (max queue length) the mutators start
  50   * processing the buffers.
  51   *
  52   * There are some interesting cases (when G1UseAdaptiveConcRefinement
  53   * is turned off):
  54   * 1) green = yellow = red = 0. In this case the mutator will process all
  55   *    buffers. Except for those that are created by the deferred updates
  56   *    machinery during a collection.
  57   * 2) green = 0. Means no caching. Can be a good way to minimize the
  58   *    amount of time spent updating rsets during a collection.
  59   */
  60   int _green_zone;
  61   int _yellow_zone;
  62   int _red_zone;
  63 
  64   int _thread_threshold_step;
  65 
  66   // We delay the refinement of 'hot' cards using the hot card cache.
  67   G1HotCardCache _hot_card_cache;
  68 
  69   // Reset the threshold step value based of the current zone boundaries.
  70   void reset_threshold_step();
  71 
  72  public:
  73   ConcurrentG1Refine(G1CollectedHeap* g1h);
  74   ~ConcurrentG1Refine();
  75 
  76   void init(); // Accomplish some initialization that has to wait.
  77   void stop();
  78 
  79   void reinitialize_threads();
  80 
  81   // Iterate over the conc refine threads
  82   void threads_do(ThreadClosure *tc);
  83 
  84   static int thread_num();
  85 
  86   void print_worker_threads_on(outputStream* st) const;
  87 
  88   void set_green_zone(int x)  { _green_zone = x;  }
  89   void set_yellow_zone(int x) { _yellow_zone = x; }
  90   void set_red_zone(int x)    { _red_zone = x;    }
  91 
  92   int green_zone() const      { return _green_zone;  }
  93   int yellow_zone() const     { return _yellow_zone; }
  94   int red_zone() const        { return _red_zone;    }
  95 
  96   int total_thread_num() const  { return _n_threads;        }
  97   int worker_thread_num() const { return _n_worker_threads; }
  98 
  99   int thread_threshold_step() const { return _thread_threshold_step; }
 100 
 101   G1HotCardCache* hot_card_cache() { return &_hot_card_cache; }
 102 };
 103 
 104 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP