Hi, On 2025-12-17 09:54:32 -0500, Andres Freund wrote: > On 2025-12-17 11:25:50 +0200, Heikki Linnakangas wrote: > > - LWLockWaitListLock() uses pg_atomic_read_u32() after spinning, > > LockBufHdr() retries directly with pg_atomic_fetch_or_u32(). > > I think here LWLockWaitListLock() is likely right - but it seems like a change > to LockBufHdr() that I would probably make in a separate commit?
FWIW, I couldn't come up with a scenario where it makes a performance difference - exclusive content locks just aren't *that* frequent. And because of that the wait list lock doesn't have similar contention as some non-content lwlocks (like XidGenLock). The most extreme workload I could think of was pgbench hammering a single sequence across many sessions. While the exclusive locks show up in wait events, the buffer header spinlock itself doesn't.. So I'm inclined to not change anything about this for now. Greetings, Andres Freund
