1 /*
   2  * Copyright (c) 2003, 2005, 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
   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 // A memory usage contains the following attributes about memory usage:
  26 //  initSize - represents the initial amount of memory (in bytes) that
  27 //     the Java virtual machine requests from the operating system
  28 //     for memory management.  The Java virtual machine may request
  29 //     additional memory from the operating system later when appropriate.
  30 //     Its value may be undefined.
  31 //  used      - represents the amount of memory currently used (in bytes).
  32 //  committed - represents the amount of memory (in bytes) that is
  33 //     guaranteed to be available for use by the Java virtual machine.
  34 //     The amount of committed memory may change over time (increase
  35 //     or decrease).  It is guaranteed to be greater than or equal
  36 //     to initSize.
  37 //  maxSize   - represents the maximum amount of memory (in bytes)
  38 //     that can be used for memory management. The maximum amount of
  39 //     memory for memory management could be less than the amount of
  40 //     committed memory.  Its value may be undefined.
  41 
  42 class MemoryUsage VALUE_OBJ_CLASS_SPEC {
  43 private:
  44   size_t _initSize;
  45   size_t _used;
  46   size_t _committed;
  47   size_t _maxSize;
  48 
  49 public:
  50   // Constructors
  51   MemoryUsage(size_t i, size_t u, size_t c, size_t m) :
  52     _initSize(i), _used(u), _committed(c), _maxSize(m) {};
  53   MemoryUsage() :
  54     _initSize(0), _used(0), _committed(0), _maxSize(0) {};
  55 
  56   size_t init_size() const { return _initSize; }
  57   size_t used()      const { return _used; }
  58   size_t committed() const { return _committed; }
  59   size_t max_size()  const { return _maxSize; }
  60 
  61   inline static jlong convert_to_jlong(size_t val) {
  62     // In the 64-bit vm, a size_t can overflow a jlong (which is signed).
  63     jlong ret;
  64     if (val == (size_t)-1) {
  65       ret = -1L;
  66     } else {
  67       NOT_LP64(ret = val;)
  68       LP64_ONLY(ret = MIN2(val, (size_t)max_jlong);)
  69     }
  70     return ret;
  71   }
  72 
  73   jlong init_size_as_jlong() const { return convert_to_jlong(_initSize); }
  74   jlong used_as_jlong()      const { return convert_to_jlong(_used); }
  75   jlong committed_as_jlong() const { return convert_to_jlong(_committed); }
  76   jlong max_size_as_jlong()  const { return convert_to_jlong(_maxSize); }
  77 };