diff -up Linux-PAM-1.1.6/modules/pam_limits/limits.conf.limits Linux-PAM-1.1.6/modules/pam_limits/limits.conf
--- Linux-PAM-1.1.6/modules/pam_limits/limits.conf.limits	2012-08-15 13:08:43.000000000 +0200
+++ Linux-PAM-1.1.6/modules/pam_limits/limits.conf	2013-03-14 16:43:37.615087671 +0100
@@ -1,5 +1,16 @@
 # /etc/security/limits.conf
 #
+#This file sets the resource limits for the users logged in via PAM.
+#It does not affect resource limits of the system services.
+#
+#Also note that configuration files in /etc/security/limits.d directory,
+#which are read in alphabetical order, override the settings in this
+#file in case the domain is the same or more specific.
+#That means for example that setting a limit for wildcard domain here
+#can be overriden with a wildcard setting in a config file in the
+#subdirectory, but a user specific setting here can be overriden only
+#with a user specific setting in the subdirectory.
+#
 #Each line describes a limit for a user in the form:
 #
 #<domain>        <type>  <item>  <value>