From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta0.migadu.com (out-176.mta0.migadu.com [91.218.175.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A945126C05 for ; Wed, 12 Feb 2025 23:50:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739404208; cv=none; b=kssIRIjOyX236RxvryQV/zw/ahJu8U52Rcwe80zyz1bO3RaB/B87sfm06XT5HK3evsW6JvgZnTfZSto0q3JnPz0c+XtRr6tdyKVqhS0efL9lTPQbYyI41ieLYXoBa6qflSZexeK3KNzxCyrxYGdBiV26tsUcFD8gj84LsOL5/7I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739404208; c=relaxed/simple; bh=peYx2iUmtjMumKtOMWeAdImuFFqD3MNQvxjR6krGFc4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sbluGwoomqRAb3oIqWEY+k03+wFAweSNgXK/8vJUkbJgi7bdg6NO4J6++vo0F29ijO2Xwe7FPCAc6gazr/ZhFSKhTnItxogRvt52LKlsKoA4ZMJvoeZuBPXV1OVEB7UkngXO1Cpvpor/wsaKMu1eSkHBmeI+Q0J2XiMv8T5sw8Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=IaZYZg/j; arc=none smtp.client-ip=91.218.175.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="IaZYZg/j" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1739404194; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TE3FTTNYmqhgXuLyPN3E/uy2Ry2GyYmbl0qHeeKrB7Y=; b=IaZYZg/jAxPXGKpYIljJL6Ihc48B5SyBLHO/oELrGPRbJ0ENmJRtXc3OQuYX9BtrErePFF dM5T7ljr/P9IuYNkek/U74ttnfDF9z6a1bEc59XhjiAlvyewf91m6GacOcrR6Yjvw/j1+E kVwVv3l3O7fZJbK/Z7snARfYVGN3BTc= Date: Wed, 12 Feb 2025 15:49:45 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v10 11/12] bpf: support selective sampling for bpf timestamping To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemdebruijn.kernel@gmail.com, willemb@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, shuah@kernel.org, ykolal@fb.com, bpf@vger.kernel.org, netdev@vger.kernel.org References: <20250212061855.71154-1-kerneljasonxing@gmail.com> <20250212061855.71154-12-kerneljasonxing@gmail.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20250212061855.71154-12-kerneljasonxing@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2/11/25 10:18 PM, Jason Xing wrote: > Add the bpf_sock_ops_enable_tx_tstamp kfunc to allow BPF programs to > selectively enable TX timestamping on a skb during tcp_sendmsg(). > > For example, BPF program will limit tracking X numbers of packets > and then will stop there instead of tracing all the sendmsgs of > matched flow all along. It would be helpful for users who cannot > afford to calculate latencies from every sendmsg call probably > due to the performance or storage space consideration. > > Signed-off-by: Jason Xing > --- > kernel/bpf/btf.c | 1 + > net/core/filter.c | 32 +++++++++++++++++++++++++++++++- > 2 files changed, 32 insertions(+), 1 deletion(-) > > diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c > index 9433b6467bbe..740210f883dc 100644 > --- a/kernel/bpf/btf.c > +++ b/kernel/bpf/btf.c > @@ -8522,6 +8522,7 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type) > case BPF_PROG_TYPE_CGROUP_SOCK_ADDR: > case BPF_PROG_TYPE_CGROUP_SOCKOPT: > case BPF_PROG_TYPE_CGROUP_SYSCTL: > + case BPF_PROG_TYPE_SOCK_OPS: > return BTF_KFUNC_HOOK_CGROUP; > case BPF_PROG_TYPE_SCHED_ACT: > return BTF_KFUNC_HOOK_SCHED_ACT; > diff --git a/net/core/filter.c b/net/core/filter.c > index 7f56d0bbeb00..36793c68b125 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -12102,6 +12102,26 @@ __bpf_kfunc int bpf_sk_assign_tcp_reqsk(struct __sk_buff *s, struct sock *sk, > #endif > } > > +__bpf_kfunc int bpf_sock_ops_enable_tx_tstamp(struct bpf_sock_ops_kern *skops, > + u64 flags) > +{ > + struct sk_buff *skb; > + struct sock *sk; > + > + if (skops->op != BPF_SOCK_OPS_TS_SND_CB) > + return -EOPNOTSUPP; It still needs to test the "flags" such that it can be used in the future.... if (flags) return -EINVAL; > + > + skb = skops->skb; > + sk = skops->sk; > + skb_shinfo(skb)->tx_flags |= SKBTX_BPF; > + if (sk_is_tcp(sk)) { Unnecessary check like this will only confuse reader. Remove it and revisit when UDP will be supported. > + TCP_SKB_CB(skb)->txstamp_ack |= TSTAMP_ACK_BPF; > + skb_shinfo(skb)->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1; > + } > + > + return 0; > +} > + > __bpf_kfunc_end_defs(); > > int bpf_dynptr_from_skb_rdonly(struct __sk_buff *skb, u64 flags, > @@ -12135,6 +12155,10 @@ BTF_KFUNCS_START(bpf_kfunc_check_set_tcp_reqsk) > BTF_ID_FLAGS(func, bpf_sk_assign_tcp_reqsk, KF_TRUSTED_ARGS) > BTF_KFUNCS_END(bpf_kfunc_check_set_tcp_reqsk) > > +BTF_KFUNCS_START(bpf_kfunc_check_set_sock_ops) > +BTF_ID_FLAGS(func, bpf_sock_ops_enable_tx_tstamp, KF_TRUSTED_ARGS) > +BTF_KFUNCS_END(bpf_kfunc_check_set_sock_ops) > + > static const struct btf_kfunc_id_set bpf_kfunc_set_skb = { > .owner = THIS_MODULE, > .set = &bpf_kfunc_check_set_skb, > @@ -12155,6 +12179,11 @@ static const struct btf_kfunc_id_set bpf_kfunc_set_tcp_reqsk = { > .set = &bpf_kfunc_check_set_tcp_reqsk, > }; > > +static const struct btf_kfunc_id_set bpf_kfunc_set_sock_ops = { > + .owner = THIS_MODULE, > + .set = &bpf_kfunc_check_set_sock_ops, > +}; > + > static int __init bpf_kfunc_init(void) > { > int ret; > @@ -12173,7 +12202,8 @@ static int __init bpf_kfunc_init(void) > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_XDP, &bpf_kfunc_set_xdp); > ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, > &bpf_kfunc_set_sock_addr); > - return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_kfunc_set_tcp_reqsk); > + ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_kfunc_set_tcp_reqsk); > + return ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SOCK_OPS, &bpf_kfunc_set_sock_ops); > } > late_initcall(bpf_kfunc_init); >