cgroup: Add ManagedOOMMemoryPressureDurationSec= override setting for units

This will allow units (scopes/slices/services) to override the default
systemd-oomd setting DefaultMemoryPressureDurationSec=.

The semantics of ManagedOOMMemoryPressureDurationSec= are:
- If >= 1 second, overrides DefaultMemoryPressureDurationSec= from oomd.conf
- If is empty, uses DefaultMemoryPressureDurationSec= from oomd.conf
- Ignored if ManagedOOMMemoryPressure= is not "kill"
- Disallowed if < 1 second

Note the corresponding dbus property is DefaultMemoryPressureDurationUSec
which is in microseconds. This is consistent with other time-based
dbus properties.

1 files changed, 21 insertions, 2 deletions

diff --git a/man/systemd.resource-control.xml b/man/systemd.resource-control.xml
index 2ffc279a35..1f16052a33 100644
--- a/man/systemd.resource-control.xml
+++ b/man/systemd.resource-control.xml
@@ -1535,10 +1535,10 @@ DeviceAllow=/dev/loop-control
         <listitem>
           <para>Overrides the default memory pressure limit set by
           <citerefentry><refentrytitle>oomd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
-          this unit (cgroup). Takes a percentage value between 0% and 100%, inclusive. This property is
-          ignored unless <varname>ManagedOOMMemoryPressure=</varname><option>kill</option>. Defaults to 0%,
+          the cgroup of this unit. Takes a percentage value between 0% and 100%, inclusive. Defaults to 0%,
           which means to use the default set by
           <citerefentry><refentrytitle>oomd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+          This property is ignored unless <varname>ManagedOOMMemoryPressure=</varname><option>kill</option>.
           </para>
 
           <xi:include href="version-info.xml" xpointer="v247"/>
@@ -1546,6 +1546,25 @@ DeviceAllow=/dev/loop-control
       </varlistentry>
 
       <varlistentry>
+        <term><varname>ManagedOOMMemoryPressureDurationSec=</varname></term>
+
+        <listitem>
+          <para>Overrides the default memory pressure duration set by
+          <citerefentry><refentrytitle>oomd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+          the cgroup of this unit. The specified value supports a time unit such as <literal>ms</literal> or
+          <literal>μs</literal>, see
+          <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+          for details on the permitted syntax. Must be set to either empty or a value of at least 1s. Defaults
+          to empty, which means to use the default set by
+          <citerefentry><refentrytitle>oomd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+          This property is ignored unless <varname>ManagedOOMMemoryPressure=</varname><option>kill</option>.
+          </para>
+
+          <xi:include href="version-info.xml" xpointer="v257"/>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><varname>ManagedOOMPreference=none|avoid|omit</varname></term>
 
         <listitem>