By default limits are taken from the /etc/security/limits.conf config file. Then individual *.conf files from the /etc/security/limits.d/ directory are read. The files are parsed one after another in the order of "C" locale. The effect of the individual files is the same as if all the files were concatenated together in the order of parsing. If a config file is explicitly specified with a module option then the files in the above directory are not parsed.
The module must not be called by a multithreaded application.
If Linux PAM is compiled with audit support the module will report when it denies access based on limit of maximum number of concurrent login sessions.
Only the session module type is provided.
For the services you need resources limits (login for example) put a the following line in /etc/pam.d/login as the last line for that service (usually after the pam_unix session line):
#%PAM-1.0 # # Resource limits imposed on login sessions via pam_limits # session required pam_limits.so
Replace "login" for each service you are using this module.
limits.conf(5), pam.d(5), pam(7).
pam_limits was initially written by Cristian Gafton <email@example.com>