<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>
<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"/>
+ <ulink url="http://cgit.freedesktop.org/systemd/tree/src/sd-readahead.c"/>
resp. <ulink
- url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.h"/></para>
+ url="http://cgit.freedesktop.org/systemd/tree/src/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
- 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>
-
- <para>If -DDISABLE_SYSTEMD is set during compilation
- this function will always return 0 and otherwise
- become a NOP.</para>
+ implemented in the reference implementation's
+ <filename>sd-readahead.c</filename> and
+ <filename>sd-readahead.h</filename> files. These
+ interfaces are available as shared library, which can
+ be compiled and linked to with the
+ <literal>libsystemd-daemon</literal>
+ <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ file. Alternatively, applications consuming this API
+ may copy the implementation into their source
+ tree. For more details about the reference
+ implementation see
+ <citerefentry><refentrytitle>sd-readahead</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+
+ <para>If the reference implementation is used as
+ drop-in files and -DDISABLE_SYSTEMD is set during
+ compilation this function will always return 0 and
+ otherwise become a NOP.</para>
</refsect1>
<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>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>
</para>
</refsect1>