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From: Martin KaFai Lau <martin.lau@linux.dev>
To: Kuniyuki Iwashima <kuniyu@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	 Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	 Eduard Zingerman <eddyz87@gmail.com>,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	 Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	 Stanislav Fomichev <sdf@fomichev.me>,
	Eric Dumazet <edumazet@google.com>,
	 Neal Cardwell <ncardwell@google.com>,
	Willem de Bruijn <willemb@google.com>,
	 Tenzin Ukyab <ukyab@berkeley.edu>,
	Kuniyuki Iwashima <kuni1840@gmail.com>,
	bpf@vger.kernel.org,  netdev@vger.kernel.org
Subject: Re: [PATCH v3 bpf-next 11/11] selftest: bpf: Add test for BPF_SOCK_OPS_RCVQ_CB.
Date: Tue, 26 May 2026 14:01:32 -0700	[thread overview]
Message-ID: <202652620533.bfqf.martin.lau@linux.dev> (raw)
In-Reply-To: <20260523083001.2911931-12-kuniyu@google.com>

On Sat, May 23, 2026 at 08:29:40AM +0000, Kuniyuki Iwashima wrote:
> +static void tcp_do_autolowat(struct bpf_sock_ops *skops,
> +			     struct tcp_autolowat_cb *cb,
> +			     struct tcp_sock *tp)
> +{
> +	struct bpf_sock_ops_kern *skops_kern;
> +	struct tcp_skb_cb *tcb;
> +	struct sk_buff *skb;
> +	u32 seq, end_seq;
> +	int ret = 0, i;
> +
> +	skops_kern = bpf_cast_to_kern_ctx(skops);
> +	skb = skops_kern->skb;
> +
> +	if (!skb)
> +		goto update;
> +
> +	tcb = bpf_core_cast(skb->cb, struct tcp_skb_cb);
> +	seq = tcb->seq;
> +	end_seq = tcb->end_seq - !!(tcb->tcp_flags & TCPHDR_FIN);
> +
> +	LOG("Start parsing skb: seq: %u, end_seq: %u, len: %u, "
> +	    "rpc_desc_seq: %u, rpc_end_seq: %u, rpc_buff_len: %u",
> +	    SEQ(seq), SEQ(end_seq), end_seq - seq,
> +	    CB_SEQ(rpc_desc_seq), CB_SEQ(rpc_end_seq), cb->rpc_desc_buff_len);
> +
> +	if (cb->rpc_desc_buff_len != RPC_DESC_SIZE) {
> +		ret = tcp_parse_descriptor(skops, cb, seq, end_seq);
> +		if (ret)
> +			goto update;
> +	}
> +
> +	i = 0;
> +
> +	while (1) {

A nit. It may be useful to take a look at progs/arena_htab.c or
rbtree_search.c on the 'for (i = zero; i < xyz && can_loop; i++)' usage.

#> ./veristat tcp_autolowat.bpf.o
Processing 'tcp_autolowat.bpf.o'...
File                 Program                   Verdict  Duration (us)  Insns  States  Program size  Jited size
-------------------  ------------------------  -------  -------------  -----  ------  ------------  ----------
tcp_autolowat.bpf.o  tcp_autolowat             success         245961  12624     338           141         939

The "Insns" could likely be reduced to ~1000s level.

      parent reply	other threads:[~2026-05-26 21:02 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-23  8:29 [PATCH v3 bpf-next 00/11] bpf: Add SOCK_OPS hooks for TCP AutoLOWAT Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 01/11] selftest: bpf: Use BPF_SOCK_OPS_ALL_CB_FLAGS + 1 for bad_cb_test_rv Kuniyuki Iwashima
2026-05-23  9:06   ` bot+bpf-ci
2026-05-23  8:29 ` [PATCH v3 bpf-next 02/11] bpf: tcp: Introduce BPF_SOCK_OPS_RCVQ_CB Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 03/11] bpf: tcp: Support bpf_skb_load_bytes() for BPF_SOCK_OPS_RCVQ_CB Kuniyuki Iwashima
2026-05-26 20:34   ` Martin KaFai Lau
2026-05-26 21:21     ` Kuniyuki Iwashima
2026-05-26 22:18       ` Martin KaFai Lau
2026-05-23  8:29 ` [PATCH v3 bpf-next 04/11] tcp: Split out __tcp_set_rcvlowat() Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 05/11] bpf: tcp: Add kfunc to adjust sk->sk_rcvlowat Kuniyuki Iwashima
2026-05-23  9:06   ` bot+bpf-ci
2026-05-23  8:29 ` [PATCH v3 bpf-next 06/11] bpf: tcp: Make BPF_SOCK_OPS_RCVQ_CB and SOCKMAP mutually exclusive Kuniyuki Iwashima
2026-05-23  9:20   ` bot+bpf-ci
2026-05-24  3:37     ` Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 07/11] bpf: mptcp: Don't support BPF_SOCK_OPS_RCVQ_CB Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 08/11] bpf: tcp: Reject BPF_SOCK_OPS_RCVQ_CB if receive queue is not empty Kuniyuki Iwashima
2026-05-23  9:20   ` bot+bpf-ci
2026-05-23  8:29 ` [PATCH v3 bpf-next 09/11] bpf: tcp: Factorise bpf_skops_established() Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 10/11] bpf: tcp: Add SOCK_OPS rcvlowat hook Kuniyuki Iwashima
2026-05-26 20:47   ` Martin KaFai Lau
2026-05-26 21:07     ` Kuniyuki Iwashima
2026-05-26 21:37       ` Amery Hung
2026-05-26 21:51         ` Kuniyuki Iwashima
2026-05-23  8:29 ` [PATCH v3 bpf-next 11/11] selftest: bpf: Add test for BPF_SOCK_OPS_RCVQ_CB Kuniyuki Iwashima
2026-05-23  9:20   ` bot+bpf-ci
2026-05-24  4:03     ` Kuniyuki Iwashima
2026-05-26 21:01   ` Martin KaFai Lau [this message]

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