diff --git a/man/udev.conf.xml b/man/udev.conf.xml
index 0f51a1aaef..f4d573ddc6 100644
--- a/man/udev.conf.xml
+++ b/man/udev.conf.xml
@@ -53,7 +53,8 @@
         <term><varname>children_max=</varname></term>
 
         <listitem>
-          <para>An integer. The maximum number of events executed in parallel.</para>
+          <para>An integer. The maximum number of events executed in parallel. When unspecified or 0 is
+          specified, the maximum is determined based on the system resources.</para>
 
           <para>This is the same as the <option>--children-max=</option> option.</para>
         </listitem>
diff --git a/man/udevadm.xml b/man/udevadm.xml
index 900bdac4b3..1c339a6b6d 100644
--- a/man/udevadm.xml
+++ b/man/udevadm.xml
@@ -607,8 +607,8 @@
           <term><option>-m</option></term>
           <term><option>--children-max=</option><replaceable>value</replaceable></term>
           <listitem>
-            <para>Set the maximum number of events, systemd-udevd will handle at the
-            same time.</para>
+            <para>Set the maximum number of events, systemd-udevd will handle at the same time. When 0 is
+            specified, then the maximum is determined based on the system resources.</para>
           </listitem>
         </varlistentry>
         <varlistentry>