http://www.islayinfo.com/islay_place_names.html gives:
'Kilmeny (G) church of, possibly, mother of Columba. Kil-MEN-ee'
Islay is in Scotland, and I'd always assumed (from the poem) that it was an Irish name, but clearly not! As for who St Columba's mother was, and what her name was, I just don't know.
Hope it helps ...