Re: Re: [[PATCH v2 for-next]] RDMA/siw: Fix SQ/RQ drain logic

[Leon Romanovsky <leon@kernel.org>]

On Fri, Oct 04, 2019 at 02:09:57PM +0000, Bernard Metzler wrote:
> -----"Leon Romanovsky" <leon@kernel.org> wrote: -----
> <...>
>
> >>   *
> >> @@ -705,6 +746,12 @@ int siw_post_send(struct ib_qp *base_qp, const
> >struct ib_send_wr *wr,
> >>  	unsigned long flags;
> >>  	int rv = 0;
> >>
> >> +	if (wr && !qp->kernel_verbs) {
> >
> >It is not related to this specific patch, but all siw "kernel_verbs"
> >should go, we have standard way to distinguish between kernel and
> >user
> >verbs.
> >
> >Thanks
> >
> Understood. I think we touched on that already.
> rdma core objects have a uobject pointer which
> is valid only if it belongs to a user land
> application. We might better use that. Let me
> see if I can compact QP objects to contain the
> ib_qp. I'd like to avoid following pointers
> potentially causing cache misses on the
> fast path. This is why I still have that
> little boolean within the siw private
> structure.

You have this variable in CQ and SRQ too.

I have serious doubts that this value gives any performance advantages.
In both flows, you will need to fetch ib_qp pointer, so you don't save
here anything by looking on kernel_verbs value.

Thanks

>
> Thanks and best regards,
> Bernard.
>