1 /*
   2  * Copyright (c) 2001, 2017, 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_G1CONCURRENTREFINE_HPP
  26 #define SHARE_VM_GC_G1_G1CONCURRENTREFINE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "utilities/globalDefinitions.hpp"
  30 
  31 // Forward decl
  32 class CardTableEntryClosure;
  33 class G1ConcurrentRefineThread;
  34 class outputStream;
  35 class ThreadClosure;
  36 
  37 class G1ConcurrentRefine : public CHeapObj<mtGC> {
  38   G1ConcurrentRefineThread** _threads;
  39   uint _n_worker_threads;
  40  /*
  41   * The value of the update buffer queue length falls into one of 3 zones:
  42   * green, yellow, red. If the value is in [0, green) nothing is
  43   * done, the buffers are left unprocessed to enable the caching effect of the
  44   * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement
  45   * threads are gradually activated. In [yellow, red) all threads are
  46   * running. If the length becomes red (max queue length) the mutators start
  47   * processing the buffers.
  48   *
  49   * There are some interesting cases (when G1UseAdaptiveConcRefinement
  50   * is turned off):
  51   * 1) green = yellow = red = 0. In this case the mutator will process all
  52   *    buffers. Except for those that are created by the deferred updates
  53   *    machinery during a collection.
  54   * 2) green = 0. Means no caching. Can be a good way to minimize the
  55   *    amount of time spent updating rsets during a collection.
  56   */
  57   size_t _green_zone;
  58   size_t _yellow_zone;
  59   size_t _red_zone;
  60   size_t _min_yellow_zone_size;
  61 
  62   G1ConcurrentRefine(size_t green_zone,
  63                      size_t yellow_zone,
  64                      size_t red_zone,
  65                      size_t min_yellow_zone_size);
  66 
  67   // Update green/yellow/red zone values based on how well goals are being met.
  68   void update_zones(double update_rs_time,
  69                     size_t update_rs_processed_buffers,
  70                     double goal_ms);
  71 
  72   // Update thread thresholds to account for updated zone values.
  73   void update_thread_thresholds();
  74 
  75  public:
  76   ~G1ConcurrentRefine();
  77 
  78   // Returns a G1ConcurrentRefine instance if succeeded to create/initialize G1ConcurrentRefine and G1ConcurrentRefineThreads.
  79   // Otherwise, returns NULL with error code.
  80   static G1ConcurrentRefine* create(jint* ecode);
  81 
  82   void stop();
  83 
  84   void adjust(double update_rs_time, size_t update_rs_processed_buffers, double goal_ms);
  85 
  86   // Iterate over all concurrent refinement threads applying the given closure.
  87   void threads_do(ThreadClosure *tc);
  88 
  89   static uint thread_num();
  90 
  91   void print_threads_on(outputStream* st) const;
  92 
  93   size_t green_zone() const      { return _green_zone;  }
  94   size_t yellow_zone() const     { return _yellow_zone; }
  95   size_t red_zone() const        { return _red_zone;    }
  96 };
  97 
  98 #endif // SHARE_VM_GC_G1_G1CONCURRENTREFINE_HPP