1/*
2 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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,
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23 */
24
25#ifndef SHARE_SERVICES_MEMORYUSAGE_HPP
26#define SHARE_SERVICES_MEMORYUSAGE_HPP
27
28#include "utilities/globalDefinitions.hpp"
29
30// A memory usage contains the following attributes about memory usage:
31// initSize - represents the initial amount of memory (in bytes) that
32// the Java virtual machine requests from the operating system
33// for memory management. The Java virtual machine may request
34// additional memory from the operating system later when appropriate.
35// Its value may be undefined.
36// used - represents the amount of memory currently used (in bytes).
37// committed - represents the amount of memory (in bytes) that is
38// guaranteed to be available for use by the Java virtual machine.
39// The amount of committed memory may change over time (increase
40// or decrease). It is guaranteed to be greater than or equal
41// to initSize.
42// maxSize - represents the maximum amount of memory (in bytes)
43// that can be used for memory management. The maximum amount of
44// memory for memory management could be less than the amount of
45// committed memory. Its value may be undefined.
46
47class MemoryUsage {
48private:
49 size_t _initSize;
50 size_t _used;
51 size_t _committed;
52 size_t _maxSize;
53
54public:
55 // Constructors
56 MemoryUsage(size_t i, size_t u, size_t c, size_t m) :
57 _initSize(i), _used(u), _committed(c), _maxSize(m) {};
58 MemoryUsage() :
59 _initSize(0), _used(0), _committed(0), _maxSize(0) {};
60
61 size_t init_size() const { return _initSize; }
62 size_t used() const { return _used; }
63 size_t committed() const { return _committed; }
64 size_t max_size() const { return _maxSize; }
65
66 static size_t undefined_size() { return (size_t) -1; }
67
68 inline static jlong convert_to_jlong(size_t val) {
69 // In the 64-bit vm, a size_t can overflow a jlong (which is signed).
70 jlong ret;
71 if (val == undefined_size()) {
72 ret = -1L;
73 } else {
74 NOT_LP64(ret = val;)
75 LP64_ONLY(ret = MIN2(val, (size_t)max_jlong);)
76 }
77 return ret;
78 }
79
80 jlong init_size_as_jlong() const { return convert_to_jlong(_initSize); }
81 jlong used_as_jlong() const { return convert_to_jlong(_used); }
82 jlong committed_as_jlong() const { return convert_to_jlong(_committed); }
83 jlong max_size_as_jlong() const { return convert_to_jlong(_maxSize); }
84};
85
86#endif // SHARE_SERVICES_MEMORYUSAGE_HPP
87