On 4/7/2024 3:00 AM, Pavel Begunkov wrote: > On 3/22/24 18:50, Kanchan Joshi wrote: >> This patchset is aimed at getting the feedback on a new io_uring >> interface that userspace can use to exchange meta buffer along with >> read/write. >> >> Two new opcodes for that: IORING_OP_READ_META and IORING_OP_WRITE_META. >> The leftover space in the SQE is used to send meta buffer pointer >> and its length. Patch #2 for this. > > I do remember there were back and forth design discussions about that > back when some other guy attempted to implement it, but have you tried > to do it not as a separate opcode? Did not try that in the first cut, thinking it would help in not touching the hot (non-meta) io path. But open to this. > It reads like all read/write opcodes might benefit from it, and it'd > be unfortunate to then be adding IORING_OP_READ_META_FIXED and > multiplicatively all other variants. Right, that's a good point.
