[PATCH net-next 01/20] tcp: minor optimization in tcp_add_backlog()
From: Eric Dumazet <hidden>
Date: 2021-11-16 00:28:26
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
From: Eric Dumazet <edumazet@google.com> If packet is going to be coalesced, sk_sndbuf/sk_rcvbuf values are not used. Defer their access to the point we need them. Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/ipv4/tcp_ipv4.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 13d868c43284584ee0c58ddfd411bb52c8b0c830..82a9e1b75405f1488d6bc5d56c11f9bc597ddb07 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c@@ -1800,8 +1800,7 @@ int tcp_v4_early_demux(struct sk_buff *skb) bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) { - u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf); - u32 tail_gso_size, tail_gso_segs; + u32 limit, tail_gso_size, tail_gso_segs; struct skb_shared_info *shinfo; const struct tcphdr *th; struct tcphdr *thtail;
@@ -1909,7 +1908,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) * to reduce memory overhead, so add a little headroom here. * Few sockets backlog are possibly concurrently non empty. */ - limit += 64*1024; + limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf) + 64*1024; if (unlikely(sk_add_backlog(sk, skb, limit))) { bh_unlock_sock(sk);
--
2.34.0.rc1.387.gb447b232ab-goog