Reference counting has much to recommend it as an approach for atomic memory reclamation. The programming model of reference counting is straightforward to understand and memory is reclaimed as soon as it's possible to be safely reclaimed. Programming reference-counted implementations without the use of Arc<T> remains difficult, owing to the lack of double-word compare and swap in Rust. Consider a Treiber stack in which the reference counter is internal to stack nodes. The head of the stack might be snapshotted, then freed by some other thread, and the subsequent read to the reference counter will be forced through an invalid pointer.
The following reference-counted Treiber stack is flawed:
use std::sync::atomic::{fence, AtomicPtr, ...
