| /* |
| * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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| */ |
| |
| #ifndef SHARE_GC_G1_G1YOUNGGENSIZER_HPP |
| #define SHARE_GC_G1_G1YOUNGGENSIZER_HPP |
| |
| #include "utilities/globalDefinitions.hpp" |
| |
| // There are three command line options related to the young gen size: |
| // NewSize, MaxNewSize and NewRatio (There is also -Xmn, but that is |
| // just a short form for NewSize==MaxNewSize). G1 will use its internal |
| // heuristics to calculate the actual young gen size, so these options |
| // basically only limit the range within which G1 can pick a young gen |
| // size. Also, these are general options taking byte sizes. G1 will |
| // internally work with a number of regions instead. So, some rounding |
| // will occur. |
| // |
| // If nothing related to the the young gen size is set on the command |
| // line we should allow the young gen to be between G1NewSizePercent |
| // and G1MaxNewSizePercent of the heap size. This means that every time |
| // the heap size changes, the limits for the young gen size will be |
| // recalculated. |
| // |
| // If only -XX:NewSize is set we should use the specified value as the |
| // minimum size for young gen. Still using G1MaxNewSizePercent of the |
| // heap as maximum. |
| // |
| // If only -XX:MaxNewSize is set we should use the specified value as the |
| // maximum size for young gen. Still using G1NewSizePercent of the heap |
| // as minimum. |
| // |
| // If -XX:NewSize and -XX:MaxNewSize are both specified we use these values. |
| // No updates when the heap size changes. There is a special case when |
| // NewSize==MaxNewSize. This is interpreted as "fixed" and will use a |
| // different heuristic for calculating the collection set when we do mixed |
| // collection. |
| // |
| // If only -XX:NewRatio is set we should use the specified ratio of the heap |
| // as both min and max. This will be interpreted as "fixed" just like the |
| // NewSize==MaxNewSize case above. But we will update the min and max |
| // every time the heap size changes. |
| // |
| // NewSize and MaxNewSize override NewRatio. So, NewRatio is ignored if it is |
| // combined with either NewSize or MaxNewSize. (A warning message is printed.) |
| class G1YoungGenSizer : public CHeapObj<mtGC> { |
| private: |
| enum SizerKind { |
| SizerDefaults, |
| SizerNewSizeOnly, |
| SizerMaxNewSizeOnly, |
| SizerMaxAndNewSize, |
| SizerNewRatio |
| }; |
| SizerKind _sizer_kind; |
| |
| // False when using a fixed young generation size due to command-line options, |
| // true otherwise. |
| bool _use_adaptive_sizing; |
| |
| uint calculate_default_min_length(uint new_number_of_heap_regions); |
| uint calculate_default_max_length(uint new_number_of_heap_regions); |
| |
| // Update the given values for minimum and maximum young gen length in regions |
| // given the number of heap regions depending on the kind of sizing algorithm. |
| void recalculate_min_max_young_length(uint number_of_heap_regions, uint* min_young_length, uint* max_young_length); |
| |
| protected: |
| uint _min_desired_young_length; |
| uint _max_desired_young_length; |
| |
| public: |
| G1YoungGenSizer(); |
| // Calculate the maximum length of the young gen given the number of regions |
| // depending on the sizing algorithm. |
| virtual void adjust_max_new_size(uint number_of_heap_regions); |
| |
| virtual void heap_size_changed(uint new_number_of_heap_regions); |
| uint min_desired_young_length() const { |
| return _min_desired_young_length; |
| } |
| uint max_desired_young_length() const { |
| return _max_desired_young_length; |
| } |
| |
| bool use_adaptive_young_list_length() const { |
| return _use_adaptive_sizing; |
| } |
| |
| static G1YoungGenSizer* create_gen_sizer(); |
| }; |
| |
| #endif // SHARE_GC_G1_G1YOUNGGENSIZER_HPP |