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
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_G1_CONCURRENTG1REFINE_HPP
  26 #define SHARE_VM_GC_G1_CONCURRENTG1REFINE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 
  31 // Forward decl
  32 class CardTableEntryClosure;
  33 class ConcurrentG1RefineThread;
  34 class G1YoungRemSetSamplingThread;
  35 class outputStream;
  36 class ThreadClosure;
  37 
  38 class ConcurrentG1Refine: public CHeapObj<mtGC> {
  39   G1YoungRemSetSamplingThread* _sample_thread;
  40 
  41   ConcurrentG1RefineThread** _threads;
  42   uint _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   size_t _green_zone;
  61   size_t _yellow_zone;
  62   size_t _red_zone;
  63   size_t _min_yellow_zone_size;
  64 
  65   ConcurrentG1Refine(size_t green_zone,
  66                      size_t yellow_zone,
  67                      size_t red_zone,
  68                      size_t min_yellow_zone_size);
  69 
  70   // Update green/yellow/red zone values based on how well goals are being met.
  71   void update_zones(double update_rs_time,
  72                     size_t update_rs_processed_buffers,
  73                     double goal_ms);
  74 
  75   // Update thread thresholds to account for updated zone values.
  76   void update_thread_thresholds();
  77 
  78  public:
  79   ~ConcurrentG1Refine();
  80 
  81   // Returns ConcurrentG1Refine instance if succeeded to create/initialize ConcurrentG1Refine and ConcurrentG1RefineThread.
  82   // Otherwise, returns NULL with error code.
  83   static ConcurrentG1Refine* create(jint* ecode);
  84 
  85   void stop();
  86 
  87   void adjust(double update_rs_time, size_t update_rs_processed_buffers, double goal_ms);
  88 
  89   // Iterate over all concurrent refinement threads
  90   void threads_do(ThreadClosure *tc);
  91 
  92   // Iterate over all worker refinement threads
  93   void worker_threads_do(ThreadClosure * tc);
  94 
  95   // The RS sampling thread has nothing to do with refinement, but is here for now.
  96   G1YoungRemSetSamplingThread * sampling_thread() const { return _sample_thread; }
  97 
  98   static uint thread_num();
  99 
 100   void print_worker_threads_on(outputStream* st) const;
 101 
 102   size_t green_zone() const      { return _green_zone;  }
 103   size_t yellow_zone() const     { return _yellow_zone; }
 104   size_t red_zone() const        { return _red_zone;    }
 105 };
 106 
 107 #endif // SHARE_VM_GC_G1_CONCURRENTG1REFINE_HPP