PetroStreet

Talking about corrosion control through cathodic protection system, does this qualify to be a preventive control or a mitigative control when we categorize this as a barrier and safety critical system, Swiss cheese model?

It has to be a protection barrier associated with process containment barrier.

Referring to IOGP 544 publication, cathodic protection itself is required to be a preventive barrier.
Through an example, as in attached snip, you can see the affect here stands within preventive.