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From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Jakub Sitnicki" <jakub@cloudflare.com>, <netdev@vger.kernel.org>,
	"Alexei Starovoitov" <ast@kernel.org>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Kuniyuki Iwashima" <kuniyu@google.com>,
	"Paolo Abeni" <pabeni@redhat.com>,
	"Stanislav Fomichev" <sdf@fomichev.me>
Cc: <bpf@vger.kernel.org>, <kernel-team@cloudflare.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Eduard Zingerman" <eddyz87@gmail.com>,
	"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
	"Martin KaFai Lau" <martin.lau@linux.dev>,
	"Song Liu" <song@kernel.org>,
	"Yonghong Song" <yonghong.song@linux.dev>,
	"Jiri Olsa" <jolsa@kernel.org>,
	"Emil Tsalapatis" <emil@etsalapatis.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Simon Horman" <horms@kernel.org>,
	"Jesper Dangaard Brouer" <hawk@kernel.org>,
	"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
	"Florian Westphal" <fw@strlen.de>,
	"Jack Wang" <163wangjack@gmail.com>
Subject: Re: [PATCH net-next v2 00/14] skb extension for BPF metadata
Date: Thu, 10 Sep 2026 08:56:37 -0700	[thread overview]
Message-ID: <DLBRCN9O0MAE.9NCB79Y636SS@gmail.com> (raw)
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. 
Then use bpf_rhashtable, populate when necessary, set bit,
attach to that new tracepoint and delete from rhash where key==skb.
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.

  parent reply	other threads:[~2026-09-10 15:56 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-10 14:02 [PATCH net-next v2 00/14] skb extension for BPF metadata Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 01/14] bpf: Introduce per-packet metadata storage for BPF programs Jakub Sitnicki
2026-09-11 10:19   ` Jiayuan Chen
2026-09-10 14:02 ` [PATCH net-next v2 02/14] bpf: Allow access to bpf_sock_ops_kern->skb Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 03/14] bpf: Make BPF skb extension survive packet scrubbing Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 04/14] selftests/bpf: Add tests for bpf_dynptr_from_skb_ext Jakub Sitnicki
2026-09-11 15:09   ` sashiko-bot
2026-09-10 14:02 ` [PATCH net-next v2 05/14] selftests/bpf: Test skb_ext on cloned skbs Jakub Sitnicki
2026-09-11 15:09   ` sashiko-bot
2026-09-10 14:02 ` [PATCH net-next v2 06/14] selftests/bpf: Test skb_ext survival across veth and GRE Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 07/14] selftests/bpf: Test skb_ext read from cgroup_skb and sk_filter hooks Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 08/14] selftests/bpf: Test skb_ext read from sock_ops and LSM hooks Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 09/14] selftests/bpf: Test skb_ext read from kfree_skb tracepoint Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 10/14] selftests/bpf: Test skb_ext read from netfilter hook Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 11/14] selftests/bpf: Test skb_ext from LWT in, out, and xmit hooks Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 12/14] selftests/bpf: Test skb_ext read from seg6local End.BPF hook Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 13/14] selftests/bpf: Test skb_ext read from sk_skb stream verdict hook Jakub Sitnicki
2026-09-10 14:02 ` [PATCH net-next v2 14/14] selftests/bpf: Use non-trivial test payload in xdp_context tests Jakub Sitnicki
2026-09-10 15:56 ` Alexei Starovoitov [this message]
2026-09-11 11:33   ` [PATCH net-next v2 00/14] skb extension for BPF metadata Jakub Sitnicki
2026-09-12  3:32     ` Alexei Starovoitov

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