If you are not able to login into your plesk control panel, please refer the below,
If you are getting the below error message, it means you are using more memory than alloted to you,
[emerg] (22)Invalid argument: could not call shmget
In such a case you need to increase the value of shmall in /etc/sysctl.conf file. Edit the file and increase the value as kern.sysv.shmall=shmmax/4096
If you need the changes to get reflected soon, please execute the following command :-
You need to reset the psa service, in this way you can access your Plesk control panel.