I didn't turn linum
on globally.
Instead I turn linum
on for the major mode in which I want it. For example:
(add-hook 'clojure-mode-hook '(lambda () (linum-on)))
or simply:
(add-hook 'clojure-mode-hook 'linum-mode)
Related here:
Turning on linum-mode when in python/c mode
and here: