I think you may want to look at:
^if its not there, do a 'kpsewhich texmf.cnf' to find it.
On my box:
%%% This file is automatically generated by update-texmf
% Please do not edit this file directly. If you want to change or add
% anything please take a look at the files in /etc/texmf/texmf.d, and
% invoke update-texmf.
looks like what you;re looking for since there's a bunch of different memory settings.
sorry about that, didn't notice the 'web2c' part. I don't have lots of time, but you should find enough info by googling the error.