rev 59304 : [mq]: 8245087-kim-sjohanss-review

   1 /*
   2  * Copyright (c) 2016, 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.
   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_GC_G1_G1HEAPSIZINGPOLICY_HPP
  26 #define SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 class G1Analytics;
  31 class G1CollectedHeap;
  32 
  33 class G1HeapSizingPolicy: public CHeapObj<mtGC> {
  34   // MinOverThresholdForGrowth must be less than the number of recorded
  35   // pause times in G1Analytics, representing the minimum number of pause
  36   // time ratios that exceed GCTimeRatio before a heap expansion will be triggered.
  37   const static uint MinOverThresholdForGrowth = 4;
  38 
  39   const G1CollectedHeap* _g1h;
  40   const G1Analytics* _analytics;
  41 
  42   const uint _num_prev_pauses_for_heuristics;
  43   // Ratio check data for determining if heap growth is necessary.
  44   uint _ratio_over_threshold_count;
  45   double _ratio_over_threshold_sum;
  46   uint _pauses_since_start;
  47 



  48 
  49 protected:
  50   G1HeapSizingPolicy(const G1CollectedHeap* g1h, const G1Analytics* analytics);
  51 public:
  52 
  53   // If an expansion would be appropriate, because recent GC overhead had
  54   // exceeded the desired limit, return an amount to expand by.
  55   virtual size_t expansion_amount();
  56 
  57   // Clear ratio tracking data used by expansion_amount().
  58   void clear_ratio_check_data();
  59 
  60   static G1HeapSizingPolicy* create(const G1CollectedHeap* g1h, const G1Analytics* analytics);
  61 };
  62 
  63 #endif // SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP
--- EOF ---