From: Maxim Mikityanskiy <maxtram95@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>,
Eelco Chaudron <echaudro@redhat.com>,
Tariq Toukan <ttoukan.linux@gmail.com>,
Tariq Toukan <tariqt@nvidia.com>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Andy Gospodarek" <andrew.gospodarek@broadcom.com>,
ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net,
hawk@kernel.org, john.fastabend@gmail.com, andrii@kernel.org,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
kpsingh@kernel.org, lorenzo.bianconi@redhat.com,
netdev@vger.kernel.org, bpf@vger.kernel.org,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Andy Gospodarek" <gospo@broadcom.com>,
"Lorenzo Bianconi" <lorenzo@kernel.org>,
gal@nvidia.com, "Saeed Mahameed" <saeedm@nvidia.com>
Subject: Re: [PATCH net-next v2] samples/bpf: fixup some tools to be able to support xdp multibuffer
Date: Tue, 10 Jan 2023 22:59:55 +0200 [thread overview]
Message-ID: <Y73Ry+nNqOkeZtaj@dragonfly.lan> (raw)
In-Reply-To: <20230103172153.58f231ba@kernel.org>
On Tue, Jan 03, 2023 at 05:21:53PM -0800, Jakub Kicinski wrote:
> On Tue, 03 Jan 2023 16:19:49 +0100 Toke Høiland-Jørgensen wrote:
> > Hmm, good question! I don't think we've ever explicitly documented any
> > assumptions one way or the other. My own mental model has certainly
> > always assumed the first frag would continue to be the same size as in
> > non-multi-buf packets.
>
> Interesting! :) My mental model was closer to GRO by frags
> so the linear part would have no data, just headers.
>
> A random datapoint is that bpf_xdp_adjust_head() seems
> to enforce that there is at least ETH_HLEN.
Also bpf_xdp_frags_increase_tail has the following check:
if (!rxq->frag_size || rxq->frag_size > xdp->frame_sz)
return -EOPNOTSUPP;
However, I can't seem to find where the `frag_size > frame_sz` part is
actually used. Maybe this condition can be dropped? Can someone shed
some light?
BTW, Tariq, we seem to have missed setting frag_size to a non-zero
value. Could you check that increasing the tail indeed doesn't work on
fragmented packets on mlx5e? I can send a oneliner to fix that.
next prev parent reply other threads:[~2023-01-10 21:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-21 17:54 [PATCH net-next v2] samples/bpf: fixup some tools to be able to support xdp multibuffer Andy Gospodarek
2022-06-22 2:00 ` patchwork-bot+netdevbpf
2023-01-03 12:55 ` Tariq Toukan
2023-01-03 15:19 ` Toke Høiland-Jørgensen
2023-01-04 1:21 ` Jakub Kicinski
2023-01-04 8:44 ` Lorenzo Bianconi
2023-01-04 12:28 ` Toke Høiland-Jørgensen
2023-01-05 1:17 ` Jakub Kicinski
2023-01-05 7:20 ` Tariq Toukan
2023-01-05 15:43 ` Toke Høiland-Jørgensen
2023-01-05 16:57 ` Andy Gospodarek
2023-01-05 18:16 ` Jakub Kicinski
2023-01-06 13:56 ` Andy Gospodarek
2023-01-08 12:33 ` Tariq Toukan
[not found] ` <8369e348-a8ec-cb10-f91f-4277e5041a27@nvidia.com>
2023-01-08 12:42 ` Tariq Toukan
2023-01-09 13:50 ` Toke Høiland-Jørgensen
2023-01-05 22:07 ` Toke Høiland-Jørgensen
2023-01-06 17:54 ` Toke Høiland-Jørgensen
2023-01-05 16:22 ` Andy Gospodarek
2023-01-10 20:59 ` Maxim Mikityanskiy [this message]
2023-01-13 21:07 ` Tariq Toukan
2023-01-25 12:49 ` Tariq Toukan
2023-01-05 16:18 ` Andy Gospodarek
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