Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
-<refentry id="sd_notify">
+<refentry id="sd_readahead" conditional='ENABLE_READAHEAD'>
<refentryinfo>
<title>sd_readahead</title>
<refnamediv>
<refname>sd_readahead</refname>
- <refpurpose>Control ongoing disk read-ahead operations</refpurpose>
+ <refpurpose>Control ongoing disk boot-time read-ahead operations</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
- <funcsynopsisinfo>#include "sd-daemon.h"</funcsynopsisinfo>
+ <funcsynopsisinfo>#include "sd-readahead.h"</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_readahead</function></funcdef>
<title>Description</title>
<para><function>sd_readahead()</function> may be
called by programs involved with early boot-up to
- control ongoing disk read-ahead operations. It may be
+ control ongoing boot-time disk read-ahead operations. It may be
used to terminate read-ahead operations in case an
uncommon disk access pattern is to be expected and
hence read-ahead replay or collection is unlikely to
<title>Notes</title>
<para>This function is provided by the reference
- implementation of APIs for new-style daemons and
- distributed with the systemd package. The algorithm
- it implements is simple, and can easily be
- reimplemented in daemons if it is important to support
- this interface without using the reference
- implementation.</para>
+ implementation of APIs for controlling boot-time
+ read-ahead and distributed with the systemd
+ package. The algorithm it implements is simple, and
+ can easily be reimplemented in daemons if it is
+ important to support this interface without using the
+ reference implementation.</para>
<para>Internally, this function creates a file in
- <filename>/dev/.systemd/readahead/</filename> which is
+ <filename>/run/systemd/readahead/</filename> which is
then used as flag file to notify the read-ahead
subsystem.</para>
<para>For details about the algorithm check the
liberally licensed reference implementation sources:
- <ulink url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.c"/>
- resp. <ulink
- url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.h"/></para>
+ <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/readahead/sd-readahead.c"/>
+ and <ulink
+ url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-readahead.h"/></para>
<para><function>sd_readahead()</function> is
implemented in the reference implementation's drop-in
- <filename>sd-daemon.c</filename> and
- <filename>sd-daemon.h</filename> files. It is
+ <filename>sd-readahead.c</filename> and
+ <filename>sd-readahead.h</filename> files. It is
recommended that applications consuming this API copy
the implementation into their source tree. For more
- details about the reference implementation see
- <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry></para>
+ details about the reference implementation, see
+ <citerefentry><refentrytitle>sd-readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry></para>
- <para>If -DDISABLE_SYSTEMD is set during compilation
+ <para>If -DDISABLE_SYSTEMD is set during compilation,
this function will always return 0 and otherwise
become a NOP.</para>
</refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd-readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>