From 8110c1a6212e430a84edd2b83fe9043def8b743e Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 28 Dec 2019 15:39:54 -0700 Subject: io_uring: add support for IORING_SETUP_CLAMP Some applications like to start small in terms of ring size, and then ramp up as needed. This is a bit tricky to do currently, since we don't advertise the max ring size. This adds IORING_SETUP_CLAMP. If set, and the values for SQ or CQ ring size exceed what we support, then clamp them at the max values instead of returning -EINVAL. Since we return the chosen ring sizes after setup, no further changes are needed on the application side. io_uring already changes the ring sizes if the application doesn't ask for power-of-two sizes, for example. Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 8ad3cece5440..29fae13395a8 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -61,6 +61,7 @@ struct io_uring_sqe { #define IORING_SETUP_SQPOLL (1U << 1) /* SQ poll thread */ #define IORING_SETUP_SQ_AFF (1U << 2) /* sq_thread_cpu is valid */ #define IORING_SETUP_CQSIZE (1U << 3) /* app defines CQ size */ +#define IORING_SETUP_CLAMP (1U << 4) /* clamp SQ/CQ ring sizes */ enum { IORING_OP_NOP, -- cgit v1.2.3