I have a HashMap that’s concurrently read by many threads and needs to be occasionally replaced in-place with a new instance.

I know I can use RwLock<HashMap> and replace the hash map after obtaining a write lock but I’m worried about performance because I need it to be highly optimized for reads and using RwLock will surely somewhat degrade the performance.

What is the proper way to do this? Maybe using ArcSwap? Also, would using ArcSwap + DashMap instead ArcSwap + HashMap be better (I suspect not because I believe DashMap uses RwLock internally)?