On 14/05/2020 19:18, Pavel Begunkov wrote: > On 14/05/2020 18:53, Jens Axboe wrote: >> On 5/14/20 9:37 AM, Pavel Begunkov wrote: >> Hmm yes good point, it should work pretty easily, barring the use cases >> that do IRQ complete. But that was also a special case with the other >> cache. >> >>> BTW, there will be a lot of problems to make either work properly with >>> IORING_FEAT_SUBMIT_STABLE. >> >> How so? Once the request is setup, any state should be retained there. > > If a late alloc fails (e.g. in __io_queue_sqe()), you'd need to file a CQE with > an error. If there is no place in CQ, to postpone the completion it'd require an > allocated req. Of course it can be dropped, but I'd prefer to have strict > guarantees. I know how to do it right for my version. Is it still just for fun thing, or you think it'll be useful for real I/O? > > That's the same reason, I have a patch stashed, that grabs links from SQ > atomically (i.e. take all SQEs of a link or none). > -- Pavel Begunkov
