I think it was more the extra layers of indirection added to function environment\effectively global variable access added in 5.2 .
The removal of scanning for changed userdata finalizer meta method in 5.2 is just a commonsense fix for bad design that made GC atomic phase run time, thats not incremental scale up with the number of GC userdata objects alive no matter if they have a finalizer or not.
The removal of scanning for changed userdata finalizer meta method in 5.2 is just a commonsense fix for bad design that made GC atomic phase run time, thats not incremental scale up with the number of GC userdata objects alive no matter if they have a finalizer or not.