Constantine's rule that peasants must do the same job as their father

Can you clarify this reference. Are you referring to the tie of coloni to their latifundia?

create feudalism?

Please define what you mean by feudalism? Peasants in western Europe from late antiquity through high middle ages are various referred to as colonus and servus (and other things besides) and often interchangeably, such that the distinction between free peasantry, unfree peasantry, and slave are often difficult to discern.

As a feudal means of economic production this was fairly unchanging (the role of centralized taxation in the Roman economy not being material difference to how surplus was extracted from agricultural labourers) from antiquity through the central middle ages. Constantine's legislation really made the tie of agricultural labourer to the latifundia more formal, but not a unique establishment in custom or law by that point; one could say that properly happened under Diocletian.

If you are referring to 'feudal' as medieval dichotomies between public and private governance, or social relations among nobility or private militarization (fiefs, vassals, knighthood), then really Constantine's rule had nothing to do with it.

Check your use of feudal here in the first few paragraphs to clarify your meaning.