In this case, the behavior is an implementation detail, not particularly defined nor explained anywhere. The mutex is an off-the-shelf parking_lot::RWMutex, from the parking_lot crate. It has eventual fairness, which means that readers will eventually acquire the lock, even during high write-throughput scenarios. They will be randomly delayed, though, up to 0.5ms. The parking_lot crate is a Rust port of WebKit’s original WTF::Lock — this 2024 changeset shows how eventual fairness was implemented there. You should read it, it has very good performance insights on mutex contention. Think of it as a palate cleanser from this blog post. Now back to the hash table & the lock.
in ways to not have too many CAs
，更多细节参见新收录的资料
}The same function using ? is shorter but loses the contextual error messages:，详情可参考新收录的资料
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