Commit 969904dc authored Sep 19, 2025 by Eric Dumazet Committed by Jakub Kicinski Sep 22, 2025

tcp: move recvmsg_inq to tcp_sock_read_txrx



Fill a hole in tcp_sock_read_txrx, instead of possibly wasting
a cache line.

Note that tcp_recvmsg_locked() is also reading tp->repair,
so this removes one cache line miss in tcp recvmsg().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250919204856.2977245-6-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>

parent 1b44d700

Documentation/networking/net_cachelines/tcp_sock.rst

+1 −1

Original line number	Diff line number	Diff line
		@@ -57,7 +57,7 @@ u8:1 is_sack_reneg read_m
		u8:2 fastopen_client_fail
		u8:4 nonagle read_write tcp_skb_entail,tcp_push_pending_frames
		u8:1 thin_lto
		u8:1 recvmsg_inq
		u8:1 recvmsg_inq read_mostly tcp_recvmsg
		u8:1 repair read_mostly tcp_write_xmit
		u8:1 frto
		u8 repair_queue

include/linux/tcp.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -232,7 +232,8 @@ struct tcp_sock {
		repair : 1,
		tcp_usec_ts : 1, /* TSval values in usec */
		is_sack_reneg:1, /* in recovery from loss with SACK reneg? */
		is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */
		is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */
		recvmsg_inq : 1;/* Indicate # of bytes in queue upon recvmsg */
		__cacheline_group_end(tcp_sock_read_txrx);

		/* RX read-mostly hotpath cache lines */
		@@ -252,7 +253,6 @@ struct tcp_sock {
		#if defined(CONFIG_TLS_DEVICE)
		void (tcp_clean_acked)(struct sock sk, u32 acked_seq);
		#endif
		u8 recvmsg_inq : 1;/* Indicate # of bytes in queue upon recvmsg */
		__cacheline_group_end(tcp_sock_read_rx);

		/* TX read-write hotpath cache lines */