Is there a more efficient way for doing this?
for item in item_list: e, new = Entry.objects.get_or_create( field1 = item.field1, field2 = item.field2, )
You can't do decent bulk insertions with get_or_create (or even create), and there's no API for doing this easily.
If your table is simple enough that creating rows with raw SQL isn't too much of a pain, it's not too hard; something like:
INSERT INTO site_entry (field1, field2) ( SELECT i.field1, i.field2 FROM (VALUES %s) AS i(field1, field2) LEFT JOIN site_entry as existing ON (existing.field1 = i.field1 AND existing.field2 = i.field2) WHERE existing.id IS NULL )
where %s is a string like
("field1, field2"), ("field3, field4"), ("field5, field6") that you'll have to create and escape properly yourself.