On Thu, Jan 23, 2025 at 10:06 AM Bernd Schubert <bernd.schubert@xxxxxxxxxxx> wrote: > > > > On 1/23/25 18:48, Joanne Koong wrote: > > On Thu, Jan 23, 2025 at 9:19 AM Bernd Schubert > > <bernd.schubert@xxxxxxxxxxx> wrote: > >> > >> Hi Joanne, > >> > >>>>> Thanks, applied and pushed with some cleanups including Luis's clamp idea. > >>>> > >>>> Hi Miklos, > >>>> > >>>> I don't think the timeouts do work with io-uring yet, I'm not sure > >>>> yet if I have time to work on that today or tomorrow (on something > >>>> else right now, I can try, but no promises). > >>> > >>> Hi Bernd, > >>> > >>> What are your thoughts on what is missing on the io-uring side for > >>> timeouts? If a request times out, it will abort the connection and > >>> AFAICT, the abort logic should already be fine for io-uring, as users > >>> can currently abort the connection through the sysfs interface and > >>> there's no internal difference in aborting through sysfs vs timeouts. > >>> > >> > >> in fuse_check_timeout() it iterates over each fud and then fpq. > >> In dev_uring.c fpq is is per queue but unrelated to fud. In current > >> fuse-io-uring fud is not cloned anymore - using fud won't work. > >> And Requests are also not queued at all on the other list > >> fuse_check_timeout() is currently checking. > > > > In the io-uring case, there still can be fuds and their associated > > fpqs given that /dev/fuse can be used still, no? So wouldn't the > > io-uring case still need this logic in fuse_check_timeout() for > > checking requests going through /dev/fuse? > > Yes, these need to be additionally checked. > > > > >> > >> Also, with a ring per core, maybe better to use > >> a per queue check that is core bound? I.e. zero locking overhead? > > > > How do you envision a queue check that bypasses grabbing the > > queue->lock? The timeout handler could be triggered on any core, so > > I'm not seeing how it could be core bound. > > I don't want to bypass it, but maybe each queue could have its own > workq and timeout checker? And then use queue_delayed_work_on()? > > > > > >> And I think we can also avoid iterating over hash lists (queue->fpq), > >> but can use the 'ent_in_userspace' list. > >> > >> We need to iterate over these other entry queues anyway: > >> > >> ent_w_req_queue > >> fuse_req_bg_queue > >> ent_commit_queue > >> > > > > Why do we need to iterate through the ent lists (ent_w_req_queue and > > ent_commit_queue)? AFAICT, in io-uring a request is either on the > > fuse_req_queue/fuse_req_bg_queue or on the fpq->processing list. Even > > when an entry has been queued to ent_w_req_queue or ent_commit_queue, > > the request itself is still queued on > > fuse_req_queue/fuse_req_bg_queue/fpq->processing. I'm not sure I > > understand why we still need to look at the ent lists? > > Yeah you are right, we could avoid ent_w_req_queue and ent_commit_queue > if we use fpq->processing, but processing consists of 256 lists - > overhead is much smaller by using the entry lists? > > > > > >> > >> And we also need to iterate over > >> > >> fuse_req_queue > >> fuse_req_bg_queue > > > > Why do we need to iterate through fuse_req_queue and > > fuse_req_bg_queue? fuse_uring_request_expired() checks the head of > > fuse_req_queue and fuse_req_bg_queue and given that requests are added > > to fuse_req_queue/fuse_req_bg_queue sequentially (eg added to the tail > > of these lists), why isn't this enough? > > I admit I'm a bit lost with that question. Aren't you pointing out > the same lists as I do? > Oh, I thought your comment was saying that we need to "iterate" over it (eg go through every request on the lists)? It currently already checks the fuse_req_queue and fuse_req_bg_queue lists (in fuse_uring_request_expired() which gets invoked in the fuse_check_timeout() timeout handler). Maybe the fuse_uring_request_expired() addition got missed - I tried to call this out in the cover letter changelog, as I had to rebase this patchset on top of the io-uring patches, so I added this function in to make it work for io-uring. I believe this suffices for now for the io uring case (with future optimizations that can be added)? Thanks, Joanne > > > > > > If it's helpful, I can resubmit this patch series so that the io-uring > > changes are isolated to its own patch (eg have patch 1 and 2 from the > > original series and then have patch 3 be the io-uring changes). > > Sounds good to me. > > > Thanks, > Bernd
