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118 lines
4.9 KiB
XML
118 lines
4.9 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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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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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd-readahead" conditional='ENABLE_READAHEAD'>
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<refentryinfo>
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<title>sd-readahead</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd-readahead</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd-readahead</refname>
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<refpurpose>Reference implementation of APIs for
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controlling boot-time read-ahead</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include "sd-readahead.h"</funcsynopsisinfo>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><filename>sd-readahead.c</filename> and
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<filename>sd-readahead.h</filename> provide a
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reference implementation for APIs for controlling boot-time
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read-ahead, as implemented by the read-ahead subsystem
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of the
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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init system.</para>
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<para>See
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<citerefentry><refentrytitle>sd_readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for more information about the function
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implemented.</para>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>This interface is provided by the reference
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implementation of APIs for controlling boot-time
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read-ahead and distributed with the systemd
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package. The algorithms it implements are simple, and
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can easily be reimplemented in daemons if it is
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important to support this interface without using the
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reference implementation. See the respective function
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man pages for details.</para>
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<para>In addition, for details about the algorithms,
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check the liberally licensed reference implementation
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sources:
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<ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/readahead/sd-readahead.c"/>
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and <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-readahead.h"/></para>
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<para>These APIs are implemented in the reference
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implementation's drop-in
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<filename>sd-readahead.c</filename> and
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<filename>sd-readahead.h</filename> files. It is
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recommended that applications consuming these APIs copy
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the implementation into their source tree, either
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verbatim or in excerpts. These interfaces are
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currently not available in a dynamic library.</para>
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<para>The functions provided by this interface become
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NOPs when -DDISABLE_SYSTEMD is set during
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compilation. In addition, if
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<filename>sd-readhead.c</filename> is compiled on
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non-Linux systems it becomes NOPs.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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