diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 59a05b9b2d..7300f3a749 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -609,7 +609,7 @@ typedef enum {
      */
     VIR_DOMAIN_MEMORY_STAT_USABLE          = 8,
 
-    /* Timestamp of the last update of statistics */
+    /* Timestamp of the last update of statistics, in seconds. */
     VIR_DOMAIN_MEMORY_STAT_LAST_UPDATE     = 9,
 
     /*
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 9a2390563a..2b45ff1553 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -821,6 +821,7 @@ B<Explanation of fields>:
   rss               - Resident Set Size of the running domain's process (in kB)
   usable            - The amount of memory which can be reclaimed by balloon
 without causing host swapping (in KB)
+  last-update       - Timestamp of the last update of statistics (in seconds)
 
 For QEMU/KVM with a memory balloon, setting the optional I<--period> to a
 value larger than 0 in seconds will allow the balloon driver to return