Hands-On Concurrency with Rust

Atomics – Safely Reclaiming Memory

In the previous chapter, we discussed the atomic primitives available to the Rust programmer, implementing higher-level synchronization primitives and some data structures built entirely of atomics. A key challenge with atomic-only programming, compared to using higher-level synchronization primitives, is memory reclamation. It is only safe to free memory once. When we build concurrent algorithms only from atomic primitives, it's very challenging to do something only once and keep performance up. That is, safely reclaiming memory requires some form of synchronization. But, as the total number of concurrent actors rise, the cost of synchronization dwarfs the latency or throughput benefits of atomic programming. ...