netdev - Re: [PATCH bpf-next v2 00/16] Decouple skb metadata tracking from MAC header offset

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Message-ID: <87ikd4v2c3.fsf@cloudflare.com>
Date: Wed, 14 Jan 2026 12:52:12 +0100
From: Jakub Sitnicki <jakub@...udflare.com>
To: bpf@...r.kernel.org
Cc: netdev@...r.kernel.org,  "David S. Miller" <davem@...emloft.net>,  Eric
 Dumazet <edumazet@...gle.com>,  Jakub Kicinski <kuba@...nel.org>,  Paolo
 Abeni <pabeni@...hat.com>,  Alexei Starovoitov <ast@...nel.org>,  Daniel
 Borkmann <daniel@...earbox.net>,  Jesper Dangaard Brouer
 <hawk@...nel.org>,  John Fastabend <john.fastabend@...il.com>,  Stanislav
 Fomichev <sdf@...ichev.me>,  Simon Horman <horms@...nel.org>,  Andrii
 Nakryiko <andrii@...nel.org>,  Martin KaFai Lau <martin.lau@...ux.dev>,
  Eduard Zingerman <eddyz87@...il.com>,  Song Liu <song@...nel.org>,
  Yonghong Song <yonghong.song@...ux.dev>,  KP Singh <kpsingh@...nel.org>,
  Hao Luo <haoluo@...gle.com>,  Jiri Olsa <jolsa@...nel.org>,
  kernel-team@...udflare.com
Subject: Re: [PATCH bpf-next v2 00/16] Decouple skb metadata tracking from
 MAC header offset

On Mon, Jan 05, 2026 at 01:14 PM +01, Jakub Sitnicki wrote:
> This series continues the effort to provide reliable access to xdp/skb
> metadata from BPF context on the receive path.

FYI, I'm dropping the effort to make xdp/skb metadata survive L2
encap/decap, following the discussion here and in [1].

Instead, I'll work on an skb local storage backed by an skb extension,
similar to what we have for cgroups/sockets/etc.

This approach avoids patching skb_push/pull call sites and implicit
allocations on hot paths.

I'm happy to split out BPF_EMIT_CALL support for prologue/epilogue if
it's considered useful on its own.

[1] https://lore.kernel.org/r/20260110-skb-meta-fixup-skb_metadata_set-calls-v1-0-1047878ed1b0@cloudflare.com

Thanks,
-jkbs