I see the argument about the page size potentially being large relative to the size of a jitted function. But, > modifying a memory mapping is very expensive

I see the argument about the page size potentially being large relative to the size of a jitted function. But, > modifying a memory mapping is very expensive It used to be true that operations on memory mappings were appallingly expensive. However, the advent of virtualization has driven a significant change in performance. IIRC, ARMv8 has a TLB invalidation operation that is per-entry, addressed by the virtual address being invalidated. You don't need to flush the entire TLB cache.