Re: [PATCH v4 bpf-next 04/10] bpf: tcp: Guard fast-path bpf_tcp_ops_call() under per-socket flag.
flat view
From: Stanislav Fomichev <hidden>
Date: 2026-10-06 22:07:07
Also in:
bpf
On 10/06, Kuniyuki Iwashima wrote:
bpf_tcp_ops.{parse_hdr,hdr_opt_len} are called for every
incoming / outgoing skb.
bpf_tcp_ops.rtt is called once per RTT, which is every
incoming skb in ping-pong workloads like tcp_rr.
Even attaching NULL callbacks in the fast path hurts performance.
Let's guard them (and write_hdr_opt) with the new per-socket flags.
__bpf_tcp_ops_call() and bpf_tcp_ops_call_flag() are added to check
cgroup_bpf_enabled(CGROUP_TCP_SOCK_OPS) first and avoid accessing
tp->bpf_tcp_ops_flags when no bpf_tcp_ops is attached.
Note that bpf_tcp_ops_hdr_opt_len() has 3 callers and previously
checked the static key both in tcp_established_options() and inside
bpf_tcp_ops_call(). Now the static key is checked once at the
beginning of bpf_tcp_ops_hdr_opt_len(), and the redundant check in
tcp_established_options() is removed.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>Acked-by: Stanislav Fomichev <sdf@fomichev.me>