On 11/21/24 9:18 AM, Pavel Begunkov wrote: > On 11/21/24 15:22, Jens Axboe wrote: >> On 11/21/24 8:15 AM, Jens Axboe wrote: >>> I'd rather entertain NOT using llists for this in the first place, as it >>> gets rid of the reversing which is the main cost here. That won't change >>> the need for a retry list necessarily, as I think we'd be better off >>> with a lockless retry list still. But at least it'd get rid of the >>> reversing. Let me see if I can dig out that patch... Totally orthogonal >>> to this topic, obviously. >> >> It's here: >> >> https://lore.kernel.org/io-uring/20240326184615.458820-3-axboe@xxxxxxxxx/ >> >> I did improve it further but never posted it again, fwiw. > > io_req_local_work_add() needs a smp_mb() after unlock, see comments, > release/unlock doesn't do it. Yep, current version I have adds a smp_mb__after_unlock_lock() for that. Will do some quick testing, but then also try the double cmpxchg on top of that if supported. -- Jens Axboe
