Re: [PATCH net-next v2 1/8] net: gro: decouple GRO from the NAPI layer

From: Jakub Kicinski
Date: Mon Jan 13 2025 - 16:02:48 EST


On Mon, 13 Jan 2025 14:50:02 +0100 Alexander Lobakin wrote:
> From: Paolo Abeni <pabeni@xxxxxxxxxx>
> Date: Thu, 9 Jan 2025 15:24:16 +0100
>
> > On 1/7/25 4:29 PM, Alexander Lobakin wrote:
> >> @@ -623,21 +622,21 @@ static gro_result_t napi_skb_finish(struct napi_struct *napi,
> >> return ret;
> >> }
> >>
> >> -gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
> >> +gro_result_t gro_receive_skb(struct gro_node *gro, struct sk_buff *skb)
> >> {
> >> gro_result_t ret;
> >>
> >> - skb_mark_napi_id(skb, napi);
> >> + __skb_mark_napi_id(skb, gro->napi_id);
> >
> > Is this the only place where gro->napi_id is needed? If so, what about
> > moving skb_mark_napi_id() in napi_gro_receive() and remove such field?
>
> Yes, only here. I thought of this, too. But this will increase the
> object code of each napi_gro_receive() caller as it's now inline. So I
> stopped on this one.
> What do you think?

What if we make napi_gro_receive() a real function (not inline)
and tail call gro_receive_skb()? Is the compiler not clever
enough too optimize that?

Very nice work in general, the napi_id is gro sticks out..