-----"Leon Romanovsky" <leon@xxxxxxxxxx> wrote: -----
>To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx>
>From: "Leon Romanovsky" <leon@xxxxxxxxxx>
>Date: 10/05/2019 10:26AM
>Cc: linux-rdma@xxxxxxxxxxxxxxx, bharat@xxxxxxxxxxx, jgg@xxxxxxxx,
>nirranjan@xxxxxxxxxxx, krishna2@xxxxxxxxxxx, bvanassche@xxxxxxx
>Subject: [EXTERNAL] Re: Re: [[PATCH v2 for-next]] RDMA/siw: Fix SQ/RQ
>drain logic
>
>On Fri, Oct 04, 2019 at 02:09:57PM +0000, Bernard Metzler wrote:
>> -----"Leon Romanovsky" <leon@xxxxxxxxxx> 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.
>
Yes, I see you are right for both CQ and SRQ.
For the CQ, we have a nested structure where
siw_cq contains ib_cq. So it is not far away.
For SRQ it is the same.
For QP's we have a split between siw_qp and ib_qp.
I will look into how to get that one solved.
I will prepare an extra patch for that whole
kernel_verbs thing, but let's not have it gating
acceptance of this unrelated patch.
Thanks very much,
Bernard.
