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<?xml version="1.0"?> |
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|
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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|
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<refentry id="get_memory_stats"> |
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|
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<refentryinfo> |
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<date>$Date: 2003/10/02 16:20:23 $</date> |
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<releaseinfo>$Id: get_memory_stats.xml,v 1.1 2003/10/02 16:20:23 tdb Exp $</releaseinfo> |
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</refentryinfo> |
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|
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<refmeta> |
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<refentrytitle>get_memory_stats</refentrytitle> |
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<manvolnum>3</manvolnum> |
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<refmiscinfo>i-scream</refmiscinfo> |
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</refmeta> |
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|
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<refnamediv> |
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<refname>get_memory_stats</refname> |
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<refname>get_swap_stats</refname> |
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<refpurpose>get VM statistics</refpurpose> |
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</refnamediv> |
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|
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<refsynopsisdiv> |
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<funcsynopsis> |
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<funcsynopsisinfo>#include <statgrab.h></funcsynopsisinfo> |
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<funcprototype> |
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<funcdef>mem_stat_t *<function>get_memory_stats</function></funcdef> |
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<void/> |
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</funcprototype> |
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<funcprototype> |
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<funcdef>swap_stat_t *<function>get_swap_stats</function></funcdef> |
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<void/> |
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</funcprototype> |
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</funcsynopsis> |
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</refsynopsisdiv> |
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|
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<refsect1> |
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<title>Description</title> |
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<para> |
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Memory statistics are accessed through the |
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<function>get_memory_stats</function> function. It returns a |
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pointer to a static <structname>mem_stat_t</structname>. |
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</para> |
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<para> |
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The <function>get_swap_stats</function> returns returns swap |
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statistics. It returns a pointer to a static |
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<structname>swap_stat_t</structname>. |
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</para> |
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<para> |
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On the FreeBSD operating system elevated privileges are required |
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to access the swap statistics. Making the program setgid kmem |
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should be sufficient. Programs running as root will not have this |
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problem. |
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</para> |
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</refsect1> |
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|
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<refsect1> |
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<title>Return Values</title> |
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|
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<para> |
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The VM system calls can return a pointer to either a |
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<structname>mem_stat_t</structname> or a |
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<structname>swap_stat_t</structname>. |
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</para> |
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|
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<programlisting> |
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typedef struct{ |
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long long total; |
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long long free; |
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long long used; |
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long long cache; |
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}mem_stat_t; |
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</programlisting> |
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|
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<variablelist> |
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<varlistentry> |
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<term> |
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<structfield>total</structfield> |
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</term> |
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<listitem> |
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<para> |
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The total amount of memory in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term> |
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<structfield>free</structfield> |
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</term> |
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<listitem> |
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<para> |
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The total free memory in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term> |
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<structfield>used</structfield> |
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</term> |
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<listitem> |
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<para> |
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The total used memory in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term> |
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<structfield>cache</structfield> |
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</term> |
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<listitem> |
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<para> |
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The amount of cache used in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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</variablelist> |
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|
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<programlisting> |
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typedef struct{ |
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long long total; |
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long long used; |
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long long free; |
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}swap_stat_t; |
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</programlisting> |
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|
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<variablelist> |
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<varlistentry> |
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<term> |
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<structfield>total</structfield> |
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</term> |
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<listitem> |
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<para> |
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The total swap space in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term> |
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<structfield>used</structfield> |
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</term> |
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<listitem> |
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<para> |
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The used swap in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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<varlistentry> |
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<term> |
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<structfield>free</structfield> |
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</term> |
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<listitem> |
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<para> |
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The free swap in bytes. |
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</para> |
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</listitem> |
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</varlistentry> |
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</variablelist> |
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</refsect1> |
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|
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<refsect1> |
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<title>Todo</title> |
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<para> |
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Add a function to hold open the file descriptor to the kernel |
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memory structures. Doing this would allow the elevated privileges |
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to be dropped early on. |
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</para> |
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</refsect1> |
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|
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<refsect1> |
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<title>See Also</title> |
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|
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<simplelist type="inline"> |
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<member> |
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<citerefentry> |
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<refentrytitle>statgrab</refentrytitle> |
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<manvolnum>3</manvolnum> |
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</citerefentry> |
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</member> |
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</simplelist> |
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</refsect1> |
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|
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<refsect1> |
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<title>Website</title> |
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|
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<simplelist type="vert"> |
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<member> |
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<ulink url="http://www.i-scream.org">http://www.i-scream.org</ulink> |
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</member> |
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</simplelist> |
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</refsect1> |
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|
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</refentry> |
