man: update docs for MemoryZSwapMax=

diff --git a/man/systemd.resource-control.xml b/man/systemd.resource-control.xml
index b2b15d8e53cc910db11da74b82424fc491a50db1..fe875a81c3dde3eb042e233512f4e48ad0fefa41 100644 (file)
--- a/man/systemd.resource-control.xml
+++ b/man/systemd.resource-control.xml
@@ -325,15 +325,32 @@
 
       <varlistentry>
         <term><varname>MemorySwapMax=<replaceable>bytes</replaceable></varname></term>
-        <term><varname>MemoryZSwapMax=<replaceable>bytes</replaceable></varname></term>
 
         <listitem>
-          <para>Specify the absolute limit on (z)swap usage of the executed processes in this unit.</para>
+          <para>Specify the absolute limit on swap usage of the executed processes in this unit.</para>
 
           <para>Takes a swap size in bytes. If the value is suffixed with K, M, G or T, the specified swap size is
           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. These settings control the
-          <literal>memory.(z)swap.max</literal> control group attributes. For details about these control group attributes,
+          <literal>memory.swap.max</literal> control group attribute. For details about this control group attribute,
+          see <ulink url="https://docs.kernel.org/admin-guide/cgroup-v2.html#memory-interface-files">Memory Interface Files</ulink>.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><varname>MemoryZSwapMax=<replaceable>bytes</replaceable></varname></term>
+
+        <listitem>
+          <para>Specify the absolute limit on zswap usage of the processes in this unit. Zswap is a lightweight compressed
+          cache for swap pages. It takes pages that are in the process of being swapped out and attempts to compress them into a
+          dynamically allocated RAM-based memory pool. If the limit specified is hit, no entries from this unit will be
+          stored in the pool until existing entries are faulted back or written out to disk. See the kernel's
+          <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/mm/zswap.html">Zswap</ulink> documentation for more details.</para>
+
+          <para>Takes a size in bytes. If the value is suffixed with K, M, G or T, the specified size is
+          parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the base 1024), respectively. If assigned the
+          special value <literal>infinity</literal>, no limit is applied. These settings control the
+          <literal>memory.zswap.max</literal> control group attribute. For details about this control group attribute,
           see <ulink url="https://docs.kernel.org/admin-guide/cgroup-v2.html#memory-interface-files">Memory Interface Files</ulink>.</para>
         </listitem>
       </varlistentry>