man/sd-readahead.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
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   8   Copyright 2010 Lennart Poettering
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  23
  24 <refentry id="sd-readahead" conditional='ENABLE_READAHEAD'>
  25
  26         <refentryinfo>
  27                 <title>sd-readahead</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>sd-readahead</refentrytitle>
  42                 <manvolnum>3</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>sd-readahead</refname>
  47                 <refpurpose>Reference implementation of APIs for
  48                 controlling boot-time read-ahead</refpurpose>
  49         </refnamediv>
  50
  51         <refsynopsisdiv>
  52                 <funcsynopsis>
  53                         <funcsynopsisinfo>#include "sd-readahead.h"</funcsynopsisinfo>
  54                 </funcsynopsis>
  55         </refsynopsisdiv>
  56
  57         <refsect1>
  58                 <title>Description</title>
  59
  60                 <para><filename>sd-readahead.c</filename> and
  61                 <filename>sd-readahead.h</filename> provide a
  62                 reference implementation for APIs for controlling boot-time
  63                 read-ahead, as implemented by the read-ahead subsystem
  64                 of the
  65                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  66                 init system.</para>
  67
  68                 <para>See
  69                 <citerefentry><refentrytitle>sd_readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  70                 for more information about the function
  71                 implemented.</para>
  72         </refsect1>
  73
  74         <refsect1>
  75                 <title>Notes</title>
  76
  77                 <para>This interface is provided by the reference
  78                 implementation of APIs for controlling boot-time
  79                 read-ahead and distributed with the systemd
  80                 package. The algorithms it implements are simple, and
  81                 can easily be reimplemented in daemons if it is
  82                 important to support this interface without using the
  83                 reference implementation. See the respective function
  84                 man pages for details.</para>
  85
  86                 <para>In addition, for details about the algorithms,
  87                 check the liberally licensed reference implementation
  88                 sources:
  89                 <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/readahead/sd-readahead.c"/>
  90                 and <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-readahead.h"/></para>
  91
  92                 <para>These APIs are implemented in the reference
  93                 implementation's drop-in
  94                 <filename>sd-readahead.c</filename> and
  95                 <filename>sd-readahead.h</filename> files. It is
  96                 recommended that applications consuming these APIs copy
  97                 the implementation into their source tree, either
  98                 verbatim or in excerpts. These interfaces are
  99                 currently not available in a dynamic library.</para>
 100
 101                 <para>The functions provided by this interface become
 102                 NOPs when -DDISABLE_SYSTEMD is set during
 103                 compilation. In addition, if
 104                 <filename>sd-readhead.c</filename> is compiled on
 105                 non-Linux systems it becomes NOPs.</para>
 106         </refsect1>
 107
 108         <refsect1>
 109                 <title>See Also</title>
 110                 <para>
 111                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 112                         <citerefentry><refentrytitle>sd_readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 113                         <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 114                 </para>
 115         </refsect1>
 116
 117 </refentry>