On Mon, 2022-12-05 at 04:53 -0700, Jens Axboe wrote:
> On 12/4/22 7:44?PM, Pavel Begunkov wrote:
> > We want to limit post_aux_cqe() to the task context when -
> > >task_complete
> > is set, and so we can't just deliver a IORING_OP_MSG_RING CQE to
> > another
> > thread. Instead of trying to invent a new delayed CQE posting
> > mechanism
> > push them into the overflow list.
>
> This is really the only one out of the series that I'm not a big fan
> of.
> If we always rely on overflow for msg_ring, then that basically
> removes
> it from being usable in a higher performance setting.
>
> The natural way to do this would be to post the cqe via task_work for
> the target, ring, but we also don't any storage available for that.
> Might still be better to alloc something ala
>
> struct tw_cqe_post {
> struct task_work work;
> s32 res;
> u32 flags;
> u64 user_data;
> }
>
> and post it with that?
>
It might work to post the whole request to the target, post the cqe,
and then return the request back to the originating ring via tw for the
msg_ring CQE and cleanup.
