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Thu, 10 Sep 2026 08:56:38 -0700 (PDT) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 10 Sep 2026 08:56:37 -0700 Message-Id: To: "Jakub Sitnicki" , , "Alexei Starovoitov" , "Jakub Kicinski" , "Kuniyuki Iwashima" , "Paolo Abeni" , "Stanislav Fomichev" Cc: , , "Daniel Borkmann" , "John Fastabend" , "Andrii Nakryiko" , "Eduard Zingerman" , "Kumar Kartikeya Dwivedi" , "Martin KaFai Lau" , "Song Liu" , "Yonghong Song" , "Jiri Olsa" , "Emil Tsalapatis" , "David S. Miller" , "Eric Dumazet" , "Simon Horman" , "Jesper Dangaard Brouer" , "Willem de Bruijn" , "Florian Westphal" , "Jack Wang" <163wangjack@gmail.com> Subject: Re: [PATCH net-next v2 00/14] skb extension for BPF metadata From: "Alexei Starovoitov" X-Mailer: aerc References: <20260910-bpf-meta-inside-skb-ext-v2-0-0b21e42180b0@cloudflare.com> In-Reply-To: <20260910-bpf-meta-inside-skb-ext-v2-0-0b21e42180b0@cloudflare.com> On Thu Sep 10, 2026 at 7:02 AM PDT, Jakub Sitnicki wrote: > > That said, as things stand we have already established in v1 [3] that for > our existing use case - attaching metadata to <1% of skbs - the so you'll be using this bpf_skb_ext only on <1% of skb-s ? How about we add a bit in skb 'special_cleanup' or something. If set it will trigger a new tracepoint during kfree_skb/consume_skb.=20 Then use bpf_rhashtable, populate when necessary, set bit, attach to that new tracepoint and delete from rhash where key=3D=3Dskb. bpf_rhash is specifically optimized for 8-byte keys. I suspect it would be faster than this approach. Overall this approach is fine from bpf perspective, but if it can be done with 1 bit + tracepoint approach that would be better.