I've been thinking of doing a similar hack. However what I would do is put
some files under /proc/sys to specify the UID number that differentiates system
processes from user processes (it's UID 100 on my systems but other people will
have different numbers) and to specify the number of processes for users (it
would be a PITA if you hard-coded this into the kernel and then installed a
program which couldn't run properly without the number being increased).
Another thing I've been thinking about is the possibility of adding more
classes of users. EG Staff could be allowed to run more processes than average
users, but we still need some limits (can't give them no limits as we do with
system UIDs).
What do you think?
Russell Coker