The entire nursery semispace is typically in L1.

L1 is only going to be about 64k per core (eg, Kaby Lake). That'll have your stack, your working set, and a tiny bit of your nursery in it... as long as you don't get associativity problems.

If you read a bunch of data before making an object, I could see you easily evicting your nursery from L1 into L2, but then you only have about 4x as much space.