From 8e74bf7f9c9f0e46066590603c3a7d1e04dbe6c4 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 19 Mar 2019 19:54:08 +0100
Subject: [PATCH] man: document new OOMPolicy= setting

---
 man/systemd-system.conf.xml | 11 +++++++++++
 man/systemd.exec.xml        | 16 +++++++++++-----
 man/systemd.service.xml     | 23 +++++++++++++++++++++++
 3 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/man/systemd-system.conf.xml b/man/systemd-system.conf.xml
index d23b3fb45d..5d1e4d1b97 100644
--- a/man/systemd-system.conf.xml
+++ b/man/systemd-system.conf.xml
@@ -364,6 +364,17 @@
         limits are only defaults for units, they are not applied to PID 1
         itself.</para></listitem>
       </varlistentry>
+
+      <varlistentry>
+        <term><varname>DefaultOOMPolicy=</varname></term>
+
+        <listitem><para>Configure the default policy for reacting to processes being killed by the Linux
+        Out-Of-Memory (OOM) killer. This may be used to pick a global default for the per-unit
+        <varname>OOMPolicy=</varname> setting. See
+        <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+        for details. Note that this default is not used for services that have <varname>Delegate=</varname>
+        turned on.</para></listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 
diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 688147ea32..df1e1e8681 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -651,11 +651,17 @@ CapabilityBoundingSet=~CAP_B CAP_C</programlisting>
       <varlistentry>
         <term><varname>OOMScoreAdjust=</varname></term>
 
-        <listitem><para>Sets the adjustment level for the Out-Of-Memory killer for executed processes. Takes an integer
-        between -1000 (to disable OOM killing for this process) and 1000 (to make killing of this process under memory
-        pressure very likely). See <ulink
-        url="https://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink> for
-        details.</para></listitem>
+        <listitem><para>Sets the adjustment value for the Linux kernel's Out-Of-Memory (OOM) killer score for
+        executed processes. Takes an integer between -1000 (to disable OOM killing of processes of this unit)
+        and 1000 (to make killing of processes of this unit under memory pressure very likely). See <ulink
+        url="https://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink> for details. If
+        not specified defaults to the OOM score adjustment level of the service manager itself, which is
+        normally at 0.</para>
+
+        <para>Use the <varname>OOMPolicy=</varname> setting of service units to configure how the service
+        manager shall react to the kernel OOM killer terminating a process of the service.  See
+        <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+        for details.</para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index 5b88417530..1f40c2ff37 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -963,6 +963,29 @@
         above.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>OOMPolicy=</varname></term>
+
+        <listitem><para>Configure the Out-Of-Memory (OOM) killer policy. On Linux, when memory becomes scarce
+        the kernel might decide to kill a running process in order to free up memory and reduce memory
+        pressure. This setting takes one of <constant>continue</constant>, <constant>stop</constant> or
+        <constant>kill</constant>. If set to <constant>continue</constant> and a process of the service is
+        killed by the kernel's OOM killer this is logged but the service continues running. If set to
+        <constant>stop</constant> the event is logged but the service is terminated cleanly by the service
+        manager. If set to <constant>kill</constant> and one of the service's processes is killed by the OOM
+        killer the kernel is instructed to kill all remaining processes of the service, too. Defaults to the
+        setting <varname>DefaultOOMPolicy=</varname> in
+        <citerefentry><refentrytitle>system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> is
+        set to, except for services where <varname>Delegate=</varname> is turned on, where it defaults to
+        <constant>continue</constant>.</para>
+
+        <para>Use the <varname>OOMScoreAdjust=</varname> setting to configure whether processes of the unit
+        shall be considered preferred or less preferred candidates for process termination by the Linux OOM
+        killer logic. See
+        <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+        details.</para></listitem>
+      </varlistentry>
+
     </variablelist>
 
     <para>Check
-- 
2.25.1