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authorDylan Yudaken <dylany@fb.com>2022-06-30 12:12:29 +0300
committerJens Axboe <axboe@kernel.dk>2022-07-25 03:39:17 +0300
commitb3fdea6ecb55c3ceea866ff66486927e51a982b3 (patch)
treea10146a5ecc4c71962b1c50ac9fca6730a3b41be /include/uapi
parentcbd25748545c709d35734deb9220e0af0a69e5d2 (diff)
downloadlinux-b3fdea6ecb55c3ceea866ff66486927e51a982b3.tar.xz
io_uring: multishot recv
Support multishot receive for io_uring. Typical server applications will run a loop where for each recv CQE it requeues another recv/recvmsg. This can be simplified by using the existing multishot functionality combined with io_uring's provided buffers. The API is to add the IORING_RECV_MULTISHOT flag to the SQE. CQEs will then be posted (with IORING_CQE_F_MORE flag set) when data is available and is read. Once an error occurs or the socket ends, the multishot will be removed and a completion without IORING_CQE_F_MORE will be posted. The benefit to this is that the recv is much more performant. * 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 Signed-off-by: Dylan Yudaken <dylany@fb.com> Link: https://lore.kernel.org/r/20220630091231.1456789-11-dylany@fb.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/uapi')
-rw-r--r--include/uapi/linux/io_uring.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index cf95354198a3..499679134961 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -263,8 +263,13 @@ enum io_uring_op {
* or receive and arm poll if that yields an
* -EAGAIN result, arm poll upfront and skip
* the initial transfer attempt.
+ *
+ * IORING_RECV_MULTISHOT Multishot recv. Sets IORING_CQE_F_MORE if
+ * the handler will continue to report
+ * CQEs on behalf of the same SQE.
*/
#define IORING_RECVSEND_POLL_FIRST (1U << 0)
+#define IORING_RECV_MULTISHOT (1U << 1)
/*
* accept flags stored in sqe->ioprio