Merge branch 'tcp-move-few-fields-for-data-locality'

Eric Dumazet says:

====================
tcp: move few fields for data locality

After recent additions (PSP and AccECN) I wanted to make another
round on fields locations to increase data locality.

This series manages to shrink TCP and TCPv6 objects by 128 bytes,
but more importantly should reduce number of touched cache lines
in TCP fast paths.

There is more to come.

v2: removed tcp CACHELINE_ASSERT_GROUP_SIZE after a kernel build bot
reported an error.
====================

Link: https://patch.msgid.link/20250919204856.2977245-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 3ca5ed02de6d..20b8c6e21fef 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -215,6 +215,9 @@ struct tcp_sock {
 	u16	gso_segs;	/* Max number of segs per GSO packet	*/
 	/* from STCP, retrans queue hinting */
 	struct sk_buff *retransmit_skb_hint;
+#if defined(CONFIG_TLS_DEVICE)
+	void (*tcp_clean_acked)(struct sock *sk, u32 acked_seq);
+#endif
 	__cacheline_group_end(tcp_sock_read_tx);
 
 	/* TXRX read-mostly hotpath cache lines */
@@ -232,13 +235,13 @@ 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 */
 	__cacheline_group_begin(tcp_sock_read_rx);
 	u32	copied_seq;	/* Head of yet unread data */
-	u32	rcv_tstamp;	/* timestamp of last received ACK (for keepalives) */
 	u32	snd_wl1;	/* Sequence for window update		*/
 	u32	tlp_high_seq;	/* snd_nxt at the time of TLP */
 	u32	rttvar_us;	/* smoothed mdev_max			*/
@@ -246,14 +249,10 @@ struct tcp_sock {
 	u16	advmss;		/* Advertised MSS			*/
 	u16	urg_data;	/* Saved octet of OOB data and control flags */
 	u32	lost;		/* Total data packets lost incl. rexmits */
+	u32	snd_ssthresh;	/* Slow start size threshold		*/
 	struct  minmax rtt_min;
 	/* OOO segments go in this rbtree. Socket lock must be held. */
 	struct rb_root	out_of_order_queue;
-#if defined(CONFIG_TLS_DEVICE)
-	void (*tcp_clean_acked)(struct sock *sk, u32 acked_seq);
-#endif
-	u32	snd_ssthresh;	/* Slow start size threshold		*/
-	u8	recvmsg_inq : 1;/* Indicate # of bytes in queue upon recvmsg */
 	__cacheline_group_end(tcp_sock_read_rx);
 
 	/* TX read-write hotpath cache lines */
@@ -319,6 +318,7 @@ struct tcp_sock {
 					*/
 	u32	app_limited;	/* limited until "delivered" reaches this val */
 	u32	rcv_wnd;	/* Current receiver window		*/
+	u32	rcv_tstamp;	/* timestamp of last received ACK (for keepalives) */
 /*
  *      Options received (usually on last packet, some only on SYN packets).
  */
@@ -448,6 +448,9 @@ struct tcp_sock {
 				 * the first SYN. */
 	u32	undo_marker;	/* snd_una upon a new recovery episode. */
 	int	undo_retrans;	/* number of undoable retransmissions. */
+	u32	mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
+			   * while socket was owned by user.
+			   */
 	u64	bytes_retrans;	/* RFC4898 tcpEStatsPerfOctetsRetrans
 				 * Total data bytes retransmitted
 				 */
@@ -494,9 +497,6 @@ struct tcp_sock {
 		u32		  probe_seq_end;
 	} mtu_probe;
 	u32     plb_rehash;     /* PLB-triggered rehash attempts */
-	u32	mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG
-			   * while socket was owned by user.
-			   */
 #if IS_ENABLED(CONFIG_MPTCP)
 	bool	is_mptcp;
 #endif