1 files changed, 22 insertions, 5 deletions
diff --git a/doc/manual/command-ref/conf-file.xml b/doc/manual/command-ref/conf-file.xml
index fb7bdf573397..d2c9145e0505 100644
--- a/doc/manual/command-ref/conf-file.xml
+++ b/doc/manual/command-ref/conf-file.xml
@@ -268,7 +268,12 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
     to mount a path in a different location in the sandbox; for
     instance, <literal>/bin=/nix-bin</literal> will mount the path
     <literal>/nix-bin</literal> as <literal>/bin</literal> inside the
-    sandbox.</para>
+    sandbox. If <replaceable>source</replaceable> is followed by
+    <literal>?</literal>, then it is not an error if
+    <replaceable>source</replaceable> does not exist; for example,
+    <literal>/dev/nvidiactl?</literal> specifies that
+    <filename>/dev/nvidiactl</filename> will only be mounted in the
+    sandbox if it exists in the host filesystem.</para>
 
     <para>Depending on how Nix was built, the default value for this option
     may be empty or provide <filename>/bin/sh</filename> as a
@@ -408,10 +413,9 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
 
   <varlistentry><term><literal>binary-caches-parallel-connections</literal></term>
 
-    <listitem><para>The maximum number of parallel HTTP connections
-    used by the binary cache substituter to get NAR info files.  This
-    number should be high to minimise latency.  It defaults to
-    25.</para></listitem>
+    <listitem><para>The maximum number of parallel TCP connections
+    used to fetch files from binary caches and by other downloads. It
+    defaults to 25. 0 means no limit.</para></listitem>
 
   </varlistentry>
 
@@ -603,6 +607,19 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
   </varlistentry>
 
 
+  <varlistentry xml:id="conf-sandbox-dev-shm-size"><term><literal>sandbox-dev-shm-size</literal></term>
+
+    <listitem><para>This option determines the maximum size of the
+    <literal>tmpfs</literal> filesystem mounted on
+    <filename>/dev/shm</filename> in Linux sandboxes. For the format,
+    see the description of the <option>size</option> option of
+    <literal>tmpfs</literal> in
+    <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>. The
+    default is <literal>50%</literal>.</para></listitem>
+
+  </varlistentry>
+
+
 </variablelist>
 
 </para>