C - Design your own free( ) function

Question

Today, I appeared for an interview and the interviewer asked me this,

1. Tell me the steps how will you design your own f

Answer 1

Memory usage patterns could be a factor. A default implementation of free can't assume anything about how often you allocate/deallocate and what sizes you allocate when you do.

For example, if you frequently allocate and deallocate objects that are of similar size, you could gain speed, memory efficiency, and reduced fragmentation by using a memory pool.

EDIT: as sharptooth noted, only makes sense to design free and malloc together. So the first thing would be to figure out how malloc is implemented.