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boundary="----oW8IgUNFNIFSxD7XOdDcjcvigBkmAw5-sdGI5qmS7_HEDRAp=_ff6c_" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230210180226epcas5p1bd2e1150de067f8af61de2bbf571594d References: <20230210180033.321377-1-joshi.k@samsung.com> <39a543d7-658c-0309-7a68-f07ffe850d0e@kernel.dk> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org ------oW8IgUNFNIFSxD7XOdDcjcvigBkmAw5-sdGI5qmS7_HEDRAp=_ff6c_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline On Wed, Apr 12, 2023 at 10:33:40AM +0800, Ming Lei wrote: >On Wed, Apr 12, 2023 at 04:18:16AM +0530, Kanchan Joshi wrote: >> > > 4. Direct NVMe queues - will there be interest in having io_uring >> > > managed NVMe queues? Sort of a new ring, for which I/O is destaged from >> > > io_uring SQE to NVMe SQE without having to go through intermediate >> > > constructs (i.e., bio/request). Hopefully,that can further amp up the >> > > efficiency of IO. >> > >> > This is interesting, and I've pondered something like that before too. I >> > think it's worth investigating and hacking up a prototype. I recently >> > had one user of IOPOLL assume that setting up a ring with IOPOLL would >> > automatically create a polled queue on the driver side and that is what >> > would be used for IO. And while that's not how it currently works, it >> > definitely does make sense and we could make some things faster like >> > that. It would also potentially easier enable cancelation referenced in >> > #1 above, if it's restricted to the queue(s) that the ring "owns". >> >> So I am looking at prototyping it, exclusively for the polled-io case. >> And for that, is there already a way to ensure that there are no >> concurrent submissions to this ring (set with IORING_SETUP_IOPOLL >> flag)? >> That will be the case generally (and submissions happen under >> uring_lock mutex), but submission may still get punted to io-wq >> worker(s) which do not take that mutex. >> So the original task and worker may get into doing concurrent submissions. > >It seems one defect for uring command support, since io_ring_ctx and >io_ring_submit_lock() can't be exported for driver. Sorry, did not follow the defect part. io-wq not acquring uring_lock in case of uring-cmd - is a defect? The same happens for direct block-io too. Or do you mean anything else here? ------oW8IgUNFNIFSxD7XOdDcjcvigBkmAw5-sdGI5qmS7_HEDRAp=_ff6c_ Content-Type: text/plain; charset="utf-8" ------oW8IgUNFNIFSxD7XOdDcjcvigBkmAw5-sdGI5qmS7_HEDRAp=_ff6c_--