diff --git a/man/oomctl.xml b/man/oomctl.xml
new file mode 100644
index 0000000000..10633b92fc
--- /dev/null
+++ b/man/oomctl.xml
@@ -0,0 +1,86 @@
+
+
+
+
+
+
+
+ oomctl
+ systemd
+
+
+
+ oomctl
+ 1
+
+
+
+ oomctl
+ Analyze the state stored in systemd-oomd
+
+
+
+
+ oomctl
+ OPTIONS
+ COMMAND
+
+
+
+
+ Description
+
+ oomctl may be used to get information about the various contexts read in by
+ the systemd1 userspace
+ out-of-memory (OOM) killer,
+ systemd-oomd8.
+
+
+
+
+ Commands
+
+ The following commands are understood:
+
+
+
+ dump
+
+ Show the current state of the cgroup(s) and system context(s) stored by
+ systemd-oomd.
+
+
+
+
+
+
+
+ Options
+
+ The following options are understood:
+
+
+
+
+
+
+
+
+
+ Exit status
+
+ On success, 0 is returned, a non-zero failure code otherwise.
+
+
+
+ See Also
+
+ systemd1,
+ systemd-oomd.service8,
+ oomd.conf5
+
+
+
+
diff --git a/man/oomd.conf.xml b/man/oomd.conf.xml
new file mode 100644
index 0000000000..e6be947c5b
--- /dev/null
+++ b/man/oomd.conf.xml
@@ -0,0 +1,88 @@
+
+
+
+
+
+
+ oomd.conf
+ systemd
+
+
+
+ oomd.conf
+ 5
+
+
+
+ oomd.conf
+ oomd.conf.d
+ Global systemd-oomd configuration files
+
+
+
+ /etc/systemd/oomd.conf
+ /etc/systemd/oomd.conf.d/*.conf
+ /usr/lib/systemd/oomd.conf.d/*.conf
+
+
+
+ Description
+
+ These files configure the various parameters of the
+ systemd1 userspace
+ out-of-memory (OOM) killer,
+ systemd-oomd.service8.
+ See systemd.syntax7
+ for a general description of the syntax.
+
+
+
+
+
+
+ [OOM] Section Options
+
+ The following options are available in the [OOM] section:
+
+
+
+ SwapUsedLimitPercent=
+
+ Sets the limit for swap usage on the system before systemd-oomd will
+ take action. If the percentage of swap used on the system is more than what is defined here,
+ systemd-oomd will act on eligible descendant cgroups, starting from the ones with the
+ highest swap usage to the lowest swap usage. Which cgroups are monitored and what
+ action gets taken depends on what the unit has configured for ManagedOOMSwap=.
+ Takes a percentage value between 0% and 100%, inclusive. Defaults to 90%.
+
+
+
+ DefaultMemoryPressureLimitPercent=
+
+ Sets the limit for memory pressure on the unit's cgroup before systemd-oomd
+ will take action. A unit can override this value with ManagedOOMMemoryPressureLimitPercent=.
+ The memory pressure for this property represents the fraction of time in a 10 second window in which all tasks
+ in the cgroup were delayed. For each monitored cgroup, if the memory pressure on that cgroup exceeds the
+ limit set for more than 30 seconds, systemd-oomd will act on eligible descendant cgroups,
+ starting from the ones with the most reclaim activity to the least reclaim activity. Which cgroups are
+ monitored and what action gets taken depends on what the unit has configured for
+ ManagedOOMMemoryPressure=. Takes a percentage value between 0% and 100%, inclusive.
+ Defaults to 60%.
+
+
+
+
+
+
+ See Also
+
+ systemd1,
+ systemd.resource-control5,
+ systemd-oomd.service8,
+ oomctl1
+
+
+
+
diff --git a/man/rules/meson.build b/man/rules/meson.build
index 00cd57420e..806561a412 100644
--- a/man/rules/meson.build
+++ b/man/rules/meson.build
@@ -45,6 +45,8 @@ manpages = [
['nss-mymachines', '8', ['libnss_mymachines.so.2'], 'ENABLE_NSS_MYMACHINES'],
['nss-resolve', '8', ['libnss_resolve.so.2'], 'ENABLE_NSS_RESOLVE'],
['nss-systemd', '8', ['libnss_systemd.so.2'], 'ENABLE_NSS_SYSTEMD'],
+ ['oomctl', '1', [], 'ENABLE_OOMD'],
+ ['oomd.conf', '5', ['oomd.conf.d'], 'ENABLE_OOMD'],
['org.freedesktop.LogControl1', '5', [], ''],
['org.freedesktop.home1', '5', [], 'ENABLE_HOMED'],
['org.freedesktop.hostname1', '5', [], 'ENABLE_HOSTNAMED'],
@@ -907,6 +909,7 @@ manpages = [
['systemd-networkd.service', '8', ['systemd-networkd'], 'ENABLE_NETWORKD'],
['systemd-notify', '1', [], ''],
['systemd-nspawn', '1', [], ''],
+ ['systemd-oomd.service', '8', ['systemd-oomd'], 'ENABLE_OOMD'],
['systemd-path', '1', [], ''],
['systemd-portabled.service', '8', ['systemd-portabled'], 'ENABLE_PORTABLED'],
['systemd-pstore.service', '8', ['systemd-pstore'], 'ENABLE_PSTORE'],
diff --git a/man/systemd-oomd.service.xml b/man/systemd-oomd.service.xml
new file mode 100644
index 0000000000..9d72373d1e
--- /dev/null
+++ b/man/systemd-oomd.service.xml
@@ -0,0 +1,98 @@
+
+
+
+
+
+
+
+ systemd-oomd.service
+ systemd
+
+
+
+ systemd-oomd.service
+ 8
+
+
+
+ systemd-oomd.service
+ systemd-oomd
+ A userspace out-of-memory (OOM) killer
+
+
+
+ systemd-oomd.service
+ /usr/lib/systemd/systemd-oomd
+
+
+
+ Description
+
+ systemd-oomd is a system service that uses cgroups-v2 and pressure stall information (PSI)
+ to monitor and take action on processes before an OOM occurs in kernel space.
+
+ You can enable monitoring and actions on units by setting ManagedOOMSwap= and/or
+ ManagedOOMMemoryPressure= to the appropriate value. systemd-oomd will
+ periodically poll enabled units' cgroup data to detect when corrective action needs to occur. When an action needs
+ to happen, it will only be performed on the descendant cgroups of the enabled units. More precisely, only cgroups with
+ memory.oom.group set to 1 and leaf cgroup nodes are eligible candidates.
+ Action will be taken recursively on all of the processes under the chosen candidate.
+
+ See
+ oomd.conf5
+ for more information about the configuration of this service.
+
+
+
+ Setup Information
+
+ The system must be running systemd with a full unified cgroup hierarchy for the expected cgroups-v2 features.
+ Furthermore, resource accounting must be turned on for all units monitored by systemd-oomd.
+ The easiest way to turn on resource accounting is by ensuring the values for DefaultCPUAccounting,
+ DefaultIOAccounting, DefaultMemoryAccounting, and
+ DefaultTasksAccounting are set to true in
+ systemd-system.conf5.
+
+ You will need a kernel compiled with PSI support. This is available in Linux 4.20 and above.
+
+ The system must also have swap enabled for systemd-oomd to function correctly. With swap
+ enabled, the system spends enough time swapping pages to let systemd-oomd react.
+ Without swap, the system enters a livelocked state much more quickly and may prevent systemd-oomd
+ from responding in a reasonable amount of time. See
+ "In defence of swap: common misconceptions"
+ for more details on swap.
+
+ Be aware that if you intend to enable monitoring and actions on user.slice,
+ user-$UID.slice, or their ancestor cgroups, it is highly recommended that your programs be
+ managed by the systemd user manager to prevent running too many processes under the same session scope (and thus
+ avoid a situation where memory intensive tasks trigger systemd-oomd to kill everything under the
+ cgroup). If you're using a desktop environment like GNOME, it already spawns many session components with the
+ systemd user manager.
+
+
+
+ Usage Recommendations
+
+ ManagedOOMSwap= works with the system-wide swap values, so setting it on the root slice
+ -.slice, and allowing all descendant cgroups to be eligible candidates may make the most
+ sense.
+
+ ManagedOOMMemoryPressure= tends to work better on the cgroups below the root slice
+ -.slice. For units which tend to have processes that are less latency sensitive (e.g.
+ system.slice), a higher limit like the default of 60% may be acceptable, as those processes
+ can usually ride out slowdowns caused by lack of memory without serious consequences. However, something like
+ user@$UID.service may prefer a much lower value like 40%.
+
+
+
+ See Also
+
+ systemd1,
+ systemd-system.conf5,
+ systemd.resource-control5,
+ oomd.conf5,
+ oomctl1
+
+
+
diff --git a/man/systemd.resource-control.xml b/man/systemd.resource-control.xml
index d72f9048e7..b40fa86145 100644
--- a/man/systemd.resource-control.xml
+++ b/man/systemd.resource-control.xml
@@ -869,6 +869,49 @@ DeviceAllow=/dev/loop-control
+
+
+ ManagedOOMSwap=auto|kill
+ ManagedOOMMemoryPressure=auto|kill
+
+
+ Specifies how
+ systemd-oomd.service8
+ will act on this unit's cgroups. Defaults to .
+
+ When set to , systemd-oomd will actively monitor this unit's
+ cgroup metrics to decide whether it needs to act. If the cgroup passes the limits set by
+ oomd.conf5 or its
+ overrides, systemd-oomd will send a SIGKILL to all of the processes
+ under the chosen candidate cgroup. Note that only descendant cgroups can be eligible candidates for killing;
+ the unit that set its property to is not a candidate (unless one of its ancestors set
+ their property to ). You can find more details on candidates and kill behavior at
+ systemd-oomd.service8
+ and oomd.conf5. Setting
+ either of these properties to will also automatically acquire
+ After= and Wants= dependencies on
+ systemd-oomd.service unless DefaultDependencies=no.
+
+
+ When set to , systemd-oomd will not actively use this cgroup's
+ data for monitoring and detection. However, if an ancestor cgroup has one of these properties set to
+ , a unit with can still be an eligible candidate for
+ systemd-oomd to act on.
+
+
+
+
+ ManagedOOMMemoryPressureLimitPercent=
+
+
+ Overrides the default memory pressure limit set by
+ oomd.conf5 for this unit
+ (cgroup). Takes a percentage value between 0% and 100%, inclusive. This property is ignored unless
+ ManagedOOMMemoryPressure=. Defaults to 0%, which means use the
+ default set by oomd.conf5.
+
+
+
@@ -1030,6 +1073,7 @@ DeviceAllow=/dev/loop-control
systemd.exec5,
systemd.directives7,
systemd.special7,
+ systemd-oomd.service8,
The documentation for control groups and specific controllers in the Linux kernel:
Control Groups v2.