From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Lorenzo Bianconi <lorenzo@kernel.org>,
bpf@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net,
kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net,
alexander.duyck@gmail.com, saeed@kernel.org
Subject: Re: [PATCH v3 bpf-next 2/2] net: xdp: introduce xdp_prepare_buff utility routine
Date: Wed, 16 Dec 2020 16:01:26 +0100 [thread overview]
Message-ID: <20201216150126.GD2036@lore-desk> (raw)
In-Reply-To: <20201216095240.43867406@carbon>
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> On Tue, 15 Dec 2020 14:47:10 +0100
> Lorenzo Bianconi <lorenzo.bianconi@redhat.com> wrote:
>
> > [...]
> > > > xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
> > > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> > > > index 4dbbbd49c389..fcd1ca3343fb 100644
> > > > --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> > > > +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> > > > @@ -2393,12 +2393,12 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
> > > >
> > > > /* retrieve a buffer from the ring */
> > > > if (!skb) {
> > > > - xdp.data = page_address(rx_buffer->page) +
> > > > - rx_buffer->page_offset;
> > > > - xdp.data_meta = xdp.data;
> > > > - xdp.data_hard_start = xdp.data -
> > > > - i40e_rx_offset(rx_ring);
> > > > - xdp.data_end = xdp.data + size;
> > > > + unsigned int offset = i40e_rx_offset(rx_ring);
> > >
> > > I now see that we could call the i40e_rx_offset() once per napi, so can
> > > you pull this variable out and have it initialized a single time? Applies
> > > to other intel drivers as well.
> >
> > ack, fine. I will fix in v4.
>
> Be careful with the Intel drivers. They have two modes (at compile
> time) depending on PAGE_SIZE in system. In one of the modes (default
> one) you can place init of xdp.frame_sz outside the NAPI loop and init a
> single time. In the other mode you cannot, and it becomes dynamic per
> packet. Intel review this carefully, please!
ack. Actully I kept the xdp.frame_sz configuration in the NAPI loop but
an Intel review will be nice.
Regards,
Lorenzo
>
> --
> Best regards,
> Jesper Dangaard Brouer
> MSc.CS, Principal Kernel Engineer at Red Hat
> LinkedIn: http://www.linkedin.com/in/brouer
>
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next prev parent reply other threads:[~2020-12-16 15:03 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-12 17:41 [PATCH v3 bpf-next 0/2] introduce xdp_init_buff/xdp_prepare_buff Lorenzo Bianconi
2020-12-12 17:41 ` [PATCH v3 bpf-next 1/2] net: xdp: introduce xdp_init_buff utility routine Lorenzo Bianconi
2020-12-16 8:35 ` Jesper Dangaard Brouer
2020-12-16 14:56 ` Lorenzo Bianconi
2020-12-12 17:41 ` [PATCH v3 bpf-next 2/2] net: xdp: introduce xdp_prepare_buff " Lorenzo Bianconi
2020-12-15 12:36 ` Maciej Fijalkowski
2020-12-15 13:47 ` Lorenzo Bianconi
2020-12-15 14:51 ` Daniel Borkmann
2020-12-15 15:06 ` Lorenzo Bianconi
2020-12-15 15:13 ` Maciej Fijalkowski
2020-12-15 20:36 ` Lorenzo Bianconi
2020-12-16 8:30 ` Jesper Dangaard Brouer
2020-12-16 8:52 ` Jesper Dangaard Brouer
2020-12-16 15:01 ` Lorenzo Bianconi [this message]
2020-12-17 18:16 ` Saeed Mahameed
2020-12-17 18:28 ` Maciej Fijalkowski
2020-12-17 20:31 ` Saeed Mahameed
2020-12-14 15:32 ` [PATCH v3 bpf-next 0/2] introduce xdp_init_buff/xdp_prepare_buff Martin Habets
2020-12-14 17:53 ` Camelia Alexandra Groza
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