Hi, On 2020-06-14 18:55:27 -0700, Noah Misch wrote: > Does something guarantee the write will be globally-visible by the time the > first concurrent accessor shows up?
The function comments say: * * Has to be done before any concurrent usage.. * * No barrier semantics. > (If not, one could (a) do an unlocked ptr->value=0, then the atomic > write, or (b) revert and improve the suppression.) I don't doubt it's > fine for the ways PostgreSQL uses atomics today, which generally > initialize an atomic before the concurrent-accessor processes even > exist. I think it's unlikely that there are cases where you could safely initialize the atomic without needing some form of synchronization before it can be used. If a barrier were needed, what'd guarantee the concurrent access happened after the initialization in the first place? Greetings, Andres Freund
