Re: [PATCH v3 1/1] io_uring: introduce non-circular SQ

[Jens Axboe <axboe@kernel.dk>]

On 1/20/26 1:47 PM, Pavel Begunkov wrote:
> Outside of SQPOLL, normally SQ entries are consumed by the time the
> submission syscall returns. For those cases we don't need a circular
> buffer and the head/tail tracking, instead the kernel can assume that
> entries always start from the beginning of the SQ at index 0. This patch
> introduces a setup flag doing exactly that. It's a simpler and helps
> to keeps SQEs hot in cache.
> 
> The feature is optional and enabled by setting IORING_SETUP_SQ_REWIND.
> The flag is rejected if passed together with SQPOLL as it'd require
> waiting for SQ before each submission. It also requires
> IORING_SETUP_NO_SQARRAY, which can be supported but it's unlikely there
> will be users, so leave more space for future optimisations.

Do you have liburing tests and man page updates for this too?

The feature itself looks fine, makes sense to keep reusing SQEs
rather than always going around the wheel.

-- 
Jens Axboe