From: Jakub Kicinski <kuba@kernel.org>
To: Larysa Zaremba <larysa.zaremba@intel.com>
Cc: bpf@vger.kernel.org, "Claudiu Manoil" <claudiu.manoil@nxp.com>,
"Vladimir Oltean" <vladimir.oltean@nxp.com>,
"Wei Fang" <wei.fang@nxp.com>,
"Clark Wang" <xiaoning.wang@nxp.com>,
"Andrew Lunn" <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Paolo Abeni" <pabeni@redhat.com>,
"Tony Nguyen" <anthony.l.nguyen@intel.com>,
"Przemek Kitszel" <przemyslaw.kitszel@intel.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"John Fastabend" <john.fastabend@gmail.com>,
"Stanislav Fomichev" <sdf@fomichev.me>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <martin.lau@linux.dev>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Song Liu" <song@kernel.org>,
"Yonghong Song" <yonghong.song@linux.dev>,
"KP Singh" <kpsingh@kernel.org>, "Hao Luo" <haoluo@google.com>,
"Jiri Olsa" <jolsa@kernel.org>, "Simon Horman" <horms@kernel.org>,
"Shuah Khan" <shuah@kernel.org>,
"Alexander Lobakin" <aleksander.lobakin@intel.com>,
"Maciej Fijalkowski" <maciej.fijalkowski@intel.com>,
"Bastien Curutchet (eBPF Foundation)"
<bastien.curutchet@bootlin.com>,
"Tushar Vyavahare" <tushar.vyavahare@intel.com>,
"Jason Xing" <kernelxing@tencent.com>,
"Ricardo B. Marlière" <rbm@suse.com>,
"Eelco Chaudron" <echaudro@redhat.com>,
"Lorenzo Bianconi" <lorenzo@kernel.org>,
"Toke Hoiland-Jorgensen" <toke@redhat.com>,
imx@lists.linux.dev, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
linux-kselftest@vger.kernel.org,
"Aleksandr Loktionov" <aleksandr.loktionov@intel.com>
Subject: Re: [PATCH bpf 0/6] Address XDP frags having negative tailroom
Date: Wed, 4 Feb 2026 17:26:28 -0800 [thread overview]
Message-ID: <20260204172628.165ac4c8@kernel.org> (raw)
In-Reply-To: <20260203105417.2302672-1-larysa.zaremba@intel.com>
On Tue, 3 Feb 2026 11:53:28 +0100 Larysa Zaremba wrote:
> Many ethernet drivers report xdp Rx queue frag size as being the same as
> DMA write size. However, the only user of this field, namely
> bpf_xdp_frags_increase_tail(), clearly expects a truesize.
truesize may not be the most fortunate term.
truesize is how much memory we charge to the skb (for memory management)
which may relate to frag size in strange ways for strange HW :S
I don't have a great term, but I have a feeling truesize already
confuses driver developers.
Note two our xdp.py tests covers tail adjust, I wonder if it would have
caught this for you. Looking at Intel's results the XDP tests don't run
due to missing BTF. Could you work with Adrian to address that?
prev parent reply other threads:[~2026-02-05 1:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-03 10:53 [PATCH bpf 0/6] Address XDP frags having negative tailroom Larysa Zaremba
2026-02-03 10:53 ` [PATCH bpf 1/6] xdp: produce a warning when calculated tailroom is negative Larysa Zaremba
2026-02-03 12:26 ` Toke Høiland-Jørgensen
2026-02-03 12:31 ` Larysa Zaremba
2026-02-03 12:38 ` Toke Høiland-Jørgensen
2026-02-03 12:54 ` Larysa Zaremba
2026-02-03 13:37 ` Toke Høiland-Jørgensen
2026-02-04 22:52 ` Martin KaFai Lau
2026-02-03 10:53 ` [PATCH bpf 2/6] ice: fix rxq info registering in mbuf packets Larysa Zaremba
2026-02-03 10:53 ` [PATCH bpf 3/6] ice: change XDP RxQ frag_size from DMA write length to truesize Larysa Zaremba
2026-02-03 10:53 ` [PATCH bpf 4/6] i40e: use truesize as XDP RxQ info frag_size Larysa Zaremba
2026-02-03 10:53 ` [PATCH bpf 5/6] idpf: " Larysa Zaremba
2026-02-03 10:53 ` [PATCH bpf 6/6] net: enetc: " Larysa Zaremba
2026-02-05 0:59 ` Vladimir Oltean
2026-02-05 1:34 ` Jakub Kicinski
2026-02-05 12:29 ` Vladimir Oltean
2026-02-05 12:41 ` Larysa Zaremba
2026-02-05 12:46 ` Vladimir Oltean
2026-02-05 13:23 ` Larysa Zaremba
2026-02-05 13:40 ` Vladimir Oltean
2026-02-06 1:54 ` Jakub Kicinski
2026-02-06 8:36 ` Larysa Zaremba
2026-02-07 2:57 ` Jakub Kicinski
2026-02-09 9:46 ` Larysa Zaremba
2026-02-08 12:59 ` Vladimir Oltean
2026-02-10 17:27 ` Dragos Tatulea
2026-02-04 22:57 ` [PATCH bpf 0/6] Address XDP frags having negative tailroom Martin KaFai Lau
2026-02-05 1:23 ` Jakub Kicinski
2026-02-05 1:26 ` Jakub Kicinski [this message]
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