Commit f1e30061 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp/dccp: remove icsk->icsk_ack.timeout 



icsk->icsk_ack.timeout can be replaced by icsk->csk_delack_timer.expires

This saves 8 bytes in TCP/DCCP sockets and helps for better cache locality.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250324203607.703850-3-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a7c428ee

Documentation/networking/net_cachelines/inet_connection_sock.rst

+0 −1
Original line number Diff line number Diff line
@@ -38,7 +38,6 @@ struct icsk_ack_u8 quick read_write w 
struct icsk_ack_u8                  pingpong

struct icsk_ack_u8                  retry                  write_mostly        read_write          inet_csk_clear_xmit_timer,tcp_rearm_rto,tcp_event_new_data_sent,tcp_write_xmit,__tcp_send_ack,tcp_send_ack,

struct icsk_ack_u8                  ato                    read_mostly         write_mostly        tcp_dec_quickack_mode,tcp_event_ack_sent,__tcp_transmit_skb,__tcp_send_ack,tcp_send_ack

struct icsk_ack_unsigned_long       timeout                read_write          read_write          inet_csk_reset_xmit_timer,tcp_connect

struct icsk_ack_u32                 lrcvtime               read_write                              tcp_finish_connect,tcp_connect,tcp_event_data_sent,__tcp_transmit_skb

struct icsk_ack_u16                 rcv_mss                write_mostly        read_mostly         __tcp_select_window,__tcp_cleanup_rbuf,tcp_initialize_rcv_mss,tcp_connect_init

struct icsk_mtup_int                search_high            read_write                              tcp_mtup_init,tcp_sync_mss,tcp_connect_init,tcp_mtu_check_reprobe,tcp_write_xmit

include/net/inet_connection_sock.h

+8 −4
Original line number Diff line number Diff line
@@ -113,7 +113,6 @@ struct inet_connection_sock { 
				  lrcv_flowlabel:20, /* last received ipv6 flowlabel	   */

				  dst_quick_ack:1, /* cache dst RTAX_QUICKACK		   */

				  unused:3;

		unsigned long	  timeout;	 /* Currently scheduled timeout		   */

		__u32		  lrcvtime;	 /* timestamp of last received data packet */

		__u16		  last_seg_size; /* Size of last incoming segment	   */

		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */
@@ -191,6 +190,12 @@ icsk_timeout(const struct inet_connection_sock *icsk) 
	return READ_ONCE(icsk->icsk_retransmit_timer.expires);

}



static inline unsigned long

icsk_delack_timeout(const struct inet_connection_sock *icsk)

{

	return READ_ONCE(icsk->icsk_delack_timer.expires);

}



static inline void inet_csk_clear_xmit_timer(struct sock *sk, const int what)

{

	struct inet_connection_sock *icsk = inet_csk(sk);
@@ -226,16 +231,15 @@ static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what, 
		when = max_when;

	}



	when += jiffies;

	if (what == ICSK_TIME_RETRANS || what == ICSK_TIME_PROBE0 ||

	    what == ICSK_TIME_LOSS_PROBE || what == ICSK_TIME_REO_TIMEOUT) {

		smp_store_release(&icsk->icsk_pending, what);

		when += jiffies;

		sk_reset_timer(sk, &icsk->icsk_retransmit_timer, when);

	} else if (what == ICSK_TIME_DACK) {

		smp_store_release(&icsk->icsk_ack.pending,

				  icsk->icsk_ack.pending | ICSK_ACK_TIMER);

		icsk->icsk_ack.timeout = jiffies + when;

		sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);

		sk_reset_timer(sk, &icsk->icsk_delack_timer, when);

	} else {

		pr_debug("inet_csk BUG: unknown timer value\n");

	}

net/dccp/output.c

+2 −3
Original line number Diff line number Diff line
@@ -627,11 +627,10 @@ void dccp_send_delayed_ack(struct sock *sk) 
			return;

		}



		if (!time_before(timeout, icsk->icsk_ack.timeout))

			timeout = icsk->icsk_ack.timeout;

		if (!time_before(timeout, icsk_delack_timeout(icsk)))

			timeout = icsk_delack_timeout(icsk);

	}

	icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;

	icsk->icsk_ack.timeout = timeout;

	sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);

}

#endif

net/dccp/timer.c

+2 −2
Original line number Diff line number Diff line
@@ -185,9 +185,9 @@ static void dccp_delack_timer(struct timer_list *t) 
	if (sk->sk_state == DCCP_CLOSED ||

	    !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))

		goto out;

	if (time_after(icsk->icsk_ack.timeout, jiffies)) {

	if (time_after(icsk_delack_timeout(icsk), jiffies)) {

		sk_reset_timer(sk, &icsk->icsk_delack_timer,

			       icsk->icsk_ack.timeout);

			       icsk_delack_timeout(icsk));

		goto out;

	}

net/ipv4/tcp_output.c

+3 −4
Original line number Diff line number Diff line
@@ -4225,17 +4225,16 @@ void tcp_send_delayed_ack(struct sock *sk) 
	/* Use new timeout only if there wasn't a older one earlier. */

	if (icsk->icsk_ack.pending & ICSK_ACK_TIMER) {

		/* If delack timer is about to expire, send ACK now. */

		if (time_before_eq(icsk->icsk_ack.timeout, jiffies + (ato >> 2))) {

		if (time_before_eq(icsk_delack_timeout(icsk), jiffies + (ato >> 2))) {

			tcp_send_ack(sk);

			return;

		}



		if (!time_before(timeout, icsk->icsk_ack.timeout))

			timeout = icsk->icsk_ack.timeout;

		if (!time_before(timeout, icsk_delack_timeout(icsk)))

			timeout = icsk_delack_timeout(icsk);

	}

	smp_store_release(&icsk->icsk_ack.pending,

			  icsk->icsk_ack.pending | ICSK_ACK_SCHED | ICSK_ACK_TIMER);

	icsk->icsk_ack.timeout = timeout;

	sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);

}