1 /*
   2  * Copyright (c) 2003, 2013, 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.
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  23  */
  24 
  25 #ifndef SHARE_VM_SERVICES_MEMORYUSAGE_HPP
  26 #define SHARE_VM_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 
  47 class MemoryUsage VALUE_OBJ_CLASS_SPEC {
  48 private:
  49   size_t _initSize;
  50   size_t _used;
  51   size_t _committed;
  52   size_t _maxSize;
  53 
  54 public:
  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_VM_SERVICES_MEMORYUSAGE_HPP