[PATCH net-next 2/2] tcp: move tcp_rate_check_app_limited() to tcp.c
From: Eric Dumazet <edumazet@google.com>
Date: 2026-01-21 09:59:29
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
tcp_rate_check_app_limited() is used from tcp_sendmsg_locked() fast path and from other callers. Move it to tcp.c so that it can be inlined in tcp_sendmsg_locked(). Small increase of code, for better TCP performance. $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 1/0 up/down: 87/0 (87) Function old new delta tcp_sendmsg_locked 4217 4304 +87 Total: Before=22566462, After=22566549, chg +0.00% Signed-off-by: Eric Dumazet <edumazet@google.com> --- include/net/tcp.h | 3 +-- net/ipv4/Makefile | 2 +- net/ipv4/tcp.c | 18 ++++++++++++++++++ net/ipv4/tcp_rate.c | 20 -------------------- 4 files changed, 20 insertions(+), 23 deletions(-) delete mode 100644 net/ipv4/tcp_rate.c
diff --git a/include/net/tcp.h b/include/net/tcp.h
index d6a77b59dddeb065d3a2df12543878ccc4704a3f..01c8ba2c42f6e3f5debb4350b2a5970d7328a93d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h@@ -809,6 +809,7 @@ static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) /* tcp.c */ void tcp_get_info(struct sock *, struct tcp_info *); +void tcp_rate_check_app_limited(struct sock *sk); /* Read 'sendfile()'-style from a TCP socket */ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
@@ -1355,8 +1356,6 @@ static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) /* From tcp_cong.c */ void tcp_set_ca_state(struct sock *sk, const u8 ca_state); -/* From tcp_rate.c */ -void tcp_rate_check_app_limited(struct sock *sk); static inline bool tcp_skb_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2) {
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index ec36d2ec059e800ec840e61a9e480e17c4c585ba..18108a6f0499907a675aead180f90a7b8ca2ea6c 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile@@ -9,7 +9,7 @@ obj-y := route.o inetpeer.o protocol.o \ inet_timewait_sock.o inet_connection_sock.o \ tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o \ tcp_minisocks.o tcp_cong.o tcp_metrics.o tcp_fastopen.o \ - tcp_rate.o tcp_recovery.o tcp_ulp.o \ + tcp_recovery.o tcp_ulp.o \ tcp_offload.o tcp_plb.o datagram.o raw.o udp.o udplite.o \ udp_offload.o arp.o icmp.o devinet.o af_inet.o igmp.o \ fib_frontend.o fib_semantics.o fib_trie.o fib_notifier.o \
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index d5319ebe24525ef9c1f0ea0297eb6c70878e0b29..148cdf3cd6233add37ea52e273cb4fb3e75fcbcb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c@@ -1074,6 +1074,24 @@ int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, int *copied, return err; } +/* If a gap is detected between sends, mark the socket application-limited. */ +void tcp_rate_check_app_limited(struct sock *sk) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (/* We have less than one packet to send. */ + tp->write_seq - tp->snd_nxt < tp->mss_cache && + /* Nothing in sending host's qdisc queues or NIC tx queue. */ + sk_wmem_alloc_get(sk) < SKB_TRUESIZE(1) && + /* We are not limited by CWND. */ + tcp_packets_in_flight(tp) < tcp_snd_cwnd(tp) && + /* All lost packets have been retransmitted. */ + tp->lost_out <= tp->retrans_out) + tp->app_limited = + (tp->delivered + tcp_packets_in_flight(tp)) ? : 1; +} +EXPORT_SYMBOL_GPL(tcp_rate_check_app_limited); + int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) { struct net_devmem_dmabuf_binding *binding = NULL;
diff --git a/net/ipv4/tcp_rate.c b/net/ipv4/tcp_rate.c
deleted file mode 100644
index 272806ba3b4e451362af1a9ede01f7ad378865cb..0000000000000000000000000000000000000000
--- a/net/ipv4/tcp_rate.c
+++ /dev/null@@ -1,20 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -#include <net/tcp.h> - -/* If a gap is detected between sends, mark the socket application-limited. */ -void tcp_rate_check_app_limited(struct sock *sk) -{ - struct tcp_sock *tp = tcp_sk(sk); - - if (/* We have less than one packet to send. */ - tp->write_seq - tp->snd_nxt < tp->mss_cache && - /* Nothing in sending host's qdisc queues or NIC tx queue. */ - sk_wmem_alloc_get(sk) < SKB_TRUESIZE(1) && - /* We are not limited by CWND. */ - tcp_packets_in_flight(tp) < tcp_snd_cwnd(tp) && - /* All lost packets have been retransmitted. */ - tp->lost_out <= tp->retrans_out) - tp->app_limited = - (tp->delivered + tcp_packets_in_flight(tp)) ? : 1; -} -EXPORT_SYMBOL_GPL(tcp_rate_check_app_limited);
--
2.52.0.457.g6b5491de43-goog