This series adds support for multishot recv/recvmsg to io_uring. The idea is that generally socket applications will be continually enqueuing a new recv() when the previous one completes. This can be improved on by allowing the application to queue a multishot receive, which will post completions as and when data is available. It uses the provided buffers feature to receive new data into a pool provided by the application. This is more performant in a few ways: * Subsequent receives are queued up straight away without requiring the application to finish a processing loop. * If there are more data in the socket (sat the provided buffer size is smaller than the socket buffer) then the data is immediately returned, improving batching. * Poll is only armed once and reused, saving CPU cycles Running a small network benchmark [1] shows improved QPS of ~6-8% over a range of loads. [1]: https://github.com/DylanZA/netbench/tree/multishot_recv Dylan Yudaken (8): io_uring: allow 0 length for buffer select io_uring: restore bgid in io_put_kbuf io_uring: allow iov_len = 0 for recvmsg and buffer select io_uring: recycle buffers on error io_uring: clean up io_poll_check_events return values io_uring: add IOU_STOP_MULTISHOT return code io_uring: add IORING_RECV_MULTISHOT flag io_uring: multishot recv include/uapi/linux/io_uring.h | 5 ++ io_uring/io_uring.h | 7 ++ io_uring/kbuf.c | 4 +- io_uring/kbuf.h | 8 ++- io_uring/net.c | 119 ++++++++++++++++++++++++++++------ io_uring/poll.c | 30 ++++++--- 6 files changed, 140 insertions(+), 33 deletions(-) base-commit: 755441b9029317d981269da0256e0a7e5a7fe2cc -- 2.30.2
