Re: [PATCH] io_uring:IORING_SETUP_SQPOLL don't need to enter io_cqring_wait

[Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>]

hi,

> From: Liming Wu <19092205@suning.com>
> 
> When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, app don't
> need to enter io_cqring_wait too. If I misunderstand, please give
> me some advise.
> 
> Signed-off-by Liming Wu <19092205@suning.com>
> ---
>   io_uring.c | 11 ++++++-----
>   1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/io_uring.c b/io_uring.c
> index b12d33b..36e884f 100644
> --- a/io_uring.c
> +++ b/io_uring.c
> @@ -7418,11 +7418,12 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
>   		 * polling again, they can rely on io_sq_thread to do polling
>   		 * work, which can reduce cpu usage and uring_lock contention.
>   		 */
> -		if (ctx->flags & IORING_SETUP_IOPOLL &&
> -		    !(ctx->flags & IORING_SETUP_SQPOLL)) {
> -			ret = io_iopoll_check(ctx, &nr_events, min_complete);
> -		} else {
> -			ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
> +		if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
> +		    if (ctx->flags & IORING_SETUP_IOPOLL) {
> +		    	ret = io_iopoll_check(ctx, &nr_events, min_complete);
> +		    } else {
> +		    	ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
> +		    }
>   		}Indeed I had checked your patch yesterday, and also did not understand why you have
above modifications. For your codes, if IORING_SETUP_SQPOLL is enabed, we'll do
nothing for IORING_ENTER_GETEVENTS, I think it's not correct.

In patch's commit message, I think you should explain more why you make such
changes, what's the benefit? You can have a look at my previous patch:
     io_uring: io_uring_enter(2) don't poll while SETUP_IOPOLL|SETUP_SQPOLL enabled

Finally, seems like that your patch did't pass checkpatch.pl, you should checkpatch
before sending patches:)

Regards,
Xiaoguang Wang

>   	}
>   
>