<refsect1>
<title>Unified and Legacy Control Group Hierarchies</title>
- <para>The unified control group hierarchy is the new version of kernel control group interface, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>. Depending on the resource type,
- there are differences in resource control capabilities. Also, because of interface changes, some resource types
- have separate set of options on the unified hierarchy.</para>
+ <para>The unified control group hierarchy is the new version of kernel control group interface, see
+ <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.
+ Depending on the resource type, there are differences in resource control capabilities. Also, because of
+ interface changes, some resource types have separate set of options on the unified hierarchy.</para>
<para>
<variablelist>
application.</para>
<para>Legacy control group hierarchy (see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>), also called cgroup-v1,
- doesn't allow safe delegation of controllers to unprivileged processes. If the system uses the legacy control group
- hierarchy, resource control is disabled for systemd user instance, see
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
- </para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/">Control Groups version 1</ulink>),
+ also called cgroup-v1, doesn't allow safe delegation of controllers to unprivileged processes. If the
+ system uses the legacy control group hierarchy, resource control is disabled for the systemd user
+ instance, see
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
is used on the system. These options take an integer value and control the <literal>cpu.weight</literal>
control group attribute. The allowed range is 1 to 10000. Defaults to 100. For details about this control
group attribute, see <ulink
- url="https://www.kernel.org/doc/
Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink> and <ulink
- url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.
+ url="https://www.kernel.org/doc/
html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink> and <ulink
+ url="https://www.kernel.org/doc/html/latest/scheduler/sched-design-CFS.html">CFS Scheduler</ulink>.
The available CPU time is split up among all units within one slice relative to their CPU time weight.</para>
<para>While <varname>StartupCPUWeight=</varname> only applies to the startup phase of the system,
available on one CPU. Use values > 100% for allotting CPU time on more than one CPU. This controls the
<literal>cpu.max</literal> attribute on the unified control group hierarchy and
<literal>cpu.cfs_quota_us</literal> on legacy. For details about these control group attributes, see <ulink
- url="https://www.kernel.org/doc/
Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink> and <ulink
+ url="https://www.kernel.org/doc/
html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink> and <ulink
url="https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt">sched-bwc.txt</ulink>.</para>
<para>Example: <varname>CPUQuota=20%</varname> ensures that the executed processes will never get more than
<para>This controls the second field of <literal>cpu.max</literal> attribute on the unified control group hierarchy
and <literal>cpu.cfs_period_us</literal> on legacy. For details about these control group attributes, see
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink> and
- <ulink url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para>
+ <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink> and
+ <ulink url="https://www.kernel.org/doc/html/latest/scheduler/sched-design-CFS.html">CFS Scheduler</ulink>.</para>
<para>Example: <varname>CPUQuotaPeriodSec=10ms</varname> to request that the CPU quota is measured in periods of 10ms.</para>
</listitem>
useful in order to always inherit all of the protection afforded by ancestors.
This controls the <literal>memory.min</literal> control group attribute. For details about this
control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>This setting is supported only if the unified control group hierarchy is used and disables
<varname>MemoryLimit=</varname>.</para>
useful in order to always inherit all of the protection afforded by ancestors.
This controls the <literal>memory.low</literal> control group attribute. For details about this
control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>This setting is supported only if the unified control group hierarchy is used and disables
<varname>MemoryLimit=</varname>.</para>
system. If assigned the
special value <literal>infinity</literal>, no memory throttling is applied. This controls the
<literal>memory.high</literal> control group attribute. For details about this control group attribute, see
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>This setting is supported only if the unified control group hierarchy is used and disables
<varname>MemoryLimit=</varname>.</para>
percentage value may be specified, which is taken relative to the installed physical memory on the system. If
assigned the special value <literal>infinity</literal>, no memory limit is applied. This controls the
<literal>memory.max</literal> control group attribute. For details about this control group attribute, see
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>This setting replaces <varname>MemoryLimit=</varname>.</para>
</listitem>
parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. If assigned the
special value <literal>infinity</literal>, no swap limit is applied. This controls the
<literal>memory.swap.max</literal> control group attribute. For details about this control group attribute,
- see <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ see <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>This setting is supported only if the unified control group hierarchy is used and disables
<varname>MemoryLimit=</varname>.</para>
of tasks or a percentage value that is taken relative to the configured maximum number of tasks on the
system. If assigned the special value <literal>infinity</literal>, no tasks limit is applied. This controls
the <literal>pids.max</literal> control group attribute. For details about this control group attribute, see
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/pids.txt">pids.txt</ulink>.</para>
+ <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/pids.html">Process Number Controller</ulink>.
+ </para>
- <para>The
- system default for this setting may be controlled with
+ <para>The system default for this setting may be controlled with
<varname>DefaultTasksMax=</varname> in
<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
</listitem>
hierarchy is used on the system. Takes a single weight value (between 1 and 10000) to set the default block
I/O weight. This controls the <literal>io.weight</literal> control group attribute, which defaults to
100. For details about this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>. The available I/O
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>. The available I/O
bandwidth is split up among all units within one slice relative to their block I/O weight.</para>
<para>While <varname>StartupIOWeight=</varname> only applies
device of the file system of the file is determined. This controls the <literal>io.weight</literal> control
group attribute, which defaults to 100. Use this option multiple times to set weights for multiple devices.
For details about this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>This setting replaces <varname>BlockIODeviceWeight=</varname> and disables settings prefixed with
<varname>BlockIO</varname> or <varname>StartupBlockIO</varname>.</para>
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 5M"). This controls the <literal>io.max</literal> control
group attributes. Use this option multiple times to set bandwidth limits for multiple devices. For details
about this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.
</para>
<para>These settings replace <varname>BlockIOReadBandwidth=</varname> and
"/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 1K"). This controls the <literal>io.max</literal> control
group attributes. Use this option multiple times to set IOPS limits for multiple devices. For details about
this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.
</para>
<para>These settings are supported only if the unified control group hierarchy is used and disable settings
system of the file is determined. This controls the <literal>io.latency</literal> control group
attribute. Use this option multiple times to set latency target for multiple devices. For details about this
control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v2.txt">cgroup-v2.txt</ulink>.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.</para>
<para>Implies <literal>IOAccounting=yes</literal>.</para>
(<emphasis>m</emphasis>knod), respectively. On cgroup-v1 this controls the
<literal>devices.allow</literal> control group attribute. For details about this control group
attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v1/devices.txt">devices.txt</ulink>. On
- cgroup-v2 this functionality is implemented using eBPF filtering.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/devices.html">Device Whitelist Controller</ulink>.
+ In the unified cgroup hierarchy this functionality is implemented using eBPF filtering.</para>
<para>The device node specifier is either a path to a device node in the file system, starting with
<filename>/dev/</filename>, or a string starting with either <literal>char-</literal> or
<para>Assign the specified CPU time share weight to the processes executed. These options take an integer
value and control the <literal>cpu.shares</literal> control group attribute. The allowed range is 2 to
262144. Defaults to 1024. For details about this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.
+ url="https://www.kernel.org/doc/html/latest/scheduler/sched-design-CFS.html">CFS Scheduler</ulink>.
The available CPU time is split up among all units within one slice relative to their CPU time share
weight.</para>
<literal>infinity</literal>, no memory limit is applied. This controls the
<literal>memory.limit_in_bytes</literal> control group attribute. For details about this control group
attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt">memory.txt</ulink>.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/memory.html">Memory Resource Controller</ulink>.</para>
<para>Implies <literal>MemoryAccounting=yes</literal>.</para>
group hierarchy is used on the system. Takes a single weight value (between 10 and 1000) to set the default
block I/O weight. This controls the <literal>blkio.weight</literal> control group attribute, which defaults to
500. For details about this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/blkio-controller.html">Block IO Controller</ulink>.
The available I/O bandwidth is split up among all units within one slice relative to their block I/O
weight.</para>
file system of the file is determined. This controls the <literal>blkio.weight_device</literal> control group
attribute, which defaults to 1000. Use this option multiple times to set weights for multiple devices. For
details about this control group attribute, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.</para>
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/blkio-controller.html">Block IO Controller</ulink>.</para>
<para>Implies
<literal>BlockIOAccounting=yes</literal>.</para>
<literal>blkio.throttle.read_bps_device</literal> and <literal>blkio.throttle.write_bps_device</literal>
control group attributes. Use this option multiple times to set bandwidth limits for multiple devices. For
details about these control group attributes, see <ulink
- url="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.
+ url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/blkio-controller.html">Block IO Controller</ulink>.
</para>
<para>Implies
<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
The documentation for control groups and specific controllers in the Linux kernel:
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>,
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/cpuacct.txt">cpuacct.txt</ulink>,
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt">memory.txt</ulink>,
- <ulink url="https://www.kernel.org/doc/Documentation/cgroup-v1/blkio-controller.txt">blkio-controller.txt</ulink>.
- <ulink url="https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt">sched-bwc.txt</ulink>.
+ <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html">Control Groups v2</ulink>.
</para>
</refsect1>
</refentry>
projects / thirdparty / systemd.git / commitdiff
