man: add a note about session autogrouping

When cpu controller is disabled, thing would often still behave as if
it was. And since the cpu controller can be enabled "magically" e.g. by
starting user@1000, add a note for users to be careful. Autogrouping
is described well in the man page, incl. how to enable or disable it,
so it should be enough to refer to that.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2023-03-07 16:08:16 +01:00
parent 396d298d6b
commit dca031d229

View file

@ -225,6 +225,13 @@ CPUWeight=20 DisableControllers=cpu / \
<varname>CPUWeight=</varname> applies to normal runtime of the system, and if the former is not set also to
the startup and shutdown phases. Using <varname>StartupCPUWeight=</varname> allows prioritizing specific services at
boot-up and shutdown differently than during normal runtime.</para>
<para>In addition to the resource allocation performed by the <option>cpu</option> controller, the
kernel may automatically divide resources based on session-id grouping, see "The autogroup feature"
in <citerefentry
project='man-pages'><refentrytitle>sched</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
The effect of this feature is similar to the <option>cpu</option> controller with no explicit
configuration, so users should be careful to not mistake one for the other.</para>
</listitem>
</varlistentry>