Commit a18056a6 authored by Eric Dumazet's avatar Eric Dumazet Committed by Paolo Abeni
Browse files

tcp: move sk_forced_mem_schedule() to tcp.c 



TCP fast path can (auto)inline this helper, instead
of (auto)inling it from tcp_send_fin().

No change of overall code size, but tcp_sendmsg() is faster.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/0 grow/shrink: 1/1 up/down: 141/-140 (1)
Function                                     old     new   delta
tcp_stream_alloc_skb                         216     357    +141
tcp_send_fin                                 688     548    -140
Total: Before=22236729, After=22236730, chg +0.00%

BTW, we might change tcp_send_fin() to use tcp_stream_alloc_skb().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarNeal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20260123111605.4089200-1-edumazet@google.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 4778a04c

net/ipv4/tcp.c

+27 −0
Original line number Diff line number Diff line
@@ -915,6 +915,33 @@ ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos, 
}

EXPORT_IPV6_MOD(tcp_splice_read);



/* We allow to exceed memory limits for FIN packets to expedite

 * connection tear down and (memory) recovery.

 * Otherwise tcp_send_fin() could be tempted to either delay FIN

 * or even be forced to close flow without any FIN.

 * In general, we want to allow one skb per socket to avoid hangs

 * with edge trigger epoll()

 */

void sk_forced_mem_schedule(struct sock *sk, int size)

{

	int delta, amt;



	delta = size - sk->sk_forward_alloc;

	if (delta <= 0)

		return;



	amt = sk_mem_pages(delta);

	sk_forward_alloc_add(sk, amt << PAGE_SHIFT);



	if (mem_cgroup_sk_enabled(sk))

		mem_cgroup_sk_charge(sk, amt, gfp_memcg_charge() | __GFP_NOFAIL);



	if (sk->sk_bypass_prot_mem)

		return;



	sk_memory_allocated_add(sk, amt);

}



struct sk_buff *tcp_stream_alloc_skb(struct sock *sk, gfp_t gfp,

				     bool force_schedule)

{

net/ipv4/tcp_output.c

+0 −27
Original line number Diff line number Diff line
@@ -3767,33 +3767,6 @@ void tcp_xmit_retransmit_queue(struct sock *sk) 
				     inet_csk(sk)->icsk_rto, true);

}



/* We allow to exceed memory limits for FIN packets to expedite

 * connection tear down and (memory) recovery.

 * Otherwise tcp_send_fin() could be tempted to either delay FIN

 * or even be forced to close flow without any FIN.

 * In general, we want to allow one skb per socket to avoid hangs

 * with edge trigger epoll()

 */

void sk_forced_mem_schedule(struct sock *sk, int size)

{

	int delta, amt;



	delta = size - sk->sk_forward_alloc;

	if (delta <= 0)

		return;



	amt = sk_mem_pages(delta);

	sk_forward_alloc_add(sk, amt << PAGE_SHIFT);



	if (mem_cgroup_sk_enabled(sk))

		mem_cgroup_sk_charge(sk, amt, gfp_memcg_charge() | __GFP_NOFAIL);



	if (sk->sk_bypass_prot_mem)

		return;



	sk_memory_allocated_add(sk, amt);

}



/* Send a FIN. The caller locks the socket for us.

 * We should try to send a FIN packet really hard, but eventually give up.

 */