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1 /* |
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2 * Copyright (c) 2019, SAP SE. All rights reserved. |
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3 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. |
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4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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5 * |
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6 * This code is free software; you can redistribute it and/or modify it |
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7 * under the terms of the GNU General Public License version 2 only, as |
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8 * published by the Free Software Foundation. |
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9 * |
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10 * This code is distributed in the hope that it will be useful, but WITHOUT |
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11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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13 * version 2 for more details (a copy is included in the LICENSE file that |
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14 * accompanied this code). |
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15 * |
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16 * You should have received a copy of the GNU General Public License version |
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17 * 2 along with this work; if not, write to the Free Software Foundation, |
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18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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19 * |
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20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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21 * or visit www.oracle.com if you need additional information or have any |
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22 * questions. |
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23 * |
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24 */ |
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25 |
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26 #ifndef SHARE_MEMORY_METASPACE_COUNTER_HPP |
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27 #define SHARE_MEMORY_METASPACE_COUNTER_HPP |
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28 |
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29 #include "metaprogramming/isSigned.hpp" |
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30 #include "runtime/atomic.hpp" |
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31 #include "utilities/debug.hpp" |
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32 #include "utilities/globalDefinitions.hpp" |
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33 |
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34 |
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35 namespace metaspace { |
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36 |
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37 // A very simple helper class which counts something, offers decrement/increment |
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38 // methods and checks for overflow/underflow on increment/decrement. |
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39 // |
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40 // (since we seem to do that alot....) |
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41 |
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42 template <class T> |
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43 class AbstractCounter { |
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44 |
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45 T _c; |
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46 |
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47 // Only allow unsigned values for now |
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48 STATIC_ASSERT(IsSigned<T>::value == false); |
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49 |
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50 public: |
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51 |
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52 AbstractCounter() : _c(0) {} |
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53 |
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54 T get() const { return _c; } |
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55 |
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56 void increment() { assert(_c + 1 > _c, "overflow"); _c ++; } |
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57 void increment_by(T v) { assert(_c + v >= _c, "overflow"); _c += v; } |
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58 void decrement() { assert(_c - 1 < _c, "underflow"); _c --; } |
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59 void decrement_by(T v) { assert(_c - v <= _c, "underflow"); _c -= v; } |
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60 |
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61 void reset() { _c = 0; } |
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62 |
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63 #ifdef ASSERT |
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64 void check(T expected) const { |
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65 assert(_c == expected, "Counter mismatch: %d, expected: %d.", |
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66 (int)_c, (int)expected); |
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67 } |
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68 #endif |
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69 |
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70 }; |
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71 |
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72 typedef AbstractCounter<size_t> SizeCounter; |
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73 typedef AbstractCounter<unsigned> IntCounter; |
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74 |
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75 |
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76 template <class T> |
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77 class AbstractAtomicCounter { |
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78 |
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79 volatile T _c; |
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80 |
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81 // Only allow unsigned values for now |
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82 STATIC_ASSERT(IsSigned<T>::value == false); |
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83 |
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84 public: |
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85 |
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86 AbstractAtomicCounter() : _c(0) {} |
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87 |
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88 T get() const { return _c; } |
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89 |
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90 void increment() { assert(_c + 1 > _c, "overflow"); Atomic::inc(&_c); } |
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91 void increment_by(T v) { assert(_c + v >= _c, "overflow"); Atomic::add(v, &_c); } |
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92 void decrement() { assert(_c - 1 < _c, "underflow"); Atomic::dec(&_c); } |
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93 void decrement_by(T v) { assert(_c - v <= _c, "underflow"); Atomic::sub(v, &_c); } |
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94 |
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95 #ifdef ASSERT |
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96 void check(T expected) const { |
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97 assert(_c == expected, "Counter mismatch: %d, expected: %d.", |
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98 (int)_c, (int)expected); |
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99 } |
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100 #endif |
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101 |
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102 }; |
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103 |
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104 typedef AbstractAtomicCounter<size_t> SizeAtomicCounter; |
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105 |
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106 |
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107 |
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108 } // namespace metaspace |
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109 |
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110 #endif // SHARE_MEMORY_METASPACE_WORDSIZECOUNTER_HPP |
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111 |