tcp: fill shinfo->gso_size at last moment

In commit cd7d8498c9a5 ("tcp: change tcp_skb_pcount() location") we stored
gso_segs in a temporary cache hot location.

This patch does the same for gso_size.

This allows to save 2 cache line misses in tcp xmit path for
the last packet that is considered but not sent because of
various conditions (cwnd, tso defer, receiver window, TSQ...)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 4 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 70a6fa8ecbd3..684f095d196e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1316,12 +1316,12 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
          * code can come after this skb later on it's better to keep
          * setting gso_size to something.
          */
-        if (!skb_shinfo(prev)->gso_size)
-                skb_shinfo(prev)->gso_size = mss;
+        if (!TCP_SKB_CB(prev)->tcp_gso_size)
+                TCP_SKB_CB(prev)->tcp_gso_size = mss;
 
         /* CHECKME: To clear or not to clear? Mimics normal skb currently */
         if (tcp_skb_pcount(skb) <= 1)
-                skb_shinfo(skb)->gso_size = 0;
+                TCP_SKB_CB(skb)->tcp_gso_size = 0;
 
         /* Difference in this won't matter, both ACKed by the same cumul. ACK */
         TCP_SKB_CB(prev)->sacked |= (TCP_SKB_CB(skb)->sacked & TCPCB_EVER_RETRANS);
@@ -2248,7 +2248,7 @@ static void tcp_mark_head_lost(struct sock *sk, int packets, int mark_head)
                             (oldcnt >= packets))
                                 break;
 
-                        mss = skb_shinfo(skb)->gso_size;
+                        mss = tcp_skb_mss(skb);
                         err = tcp_fragment(sk, skb, (packets - oldcnt) * mss,
                                            mss, GFP_ATOMIC);
                         if (err < 0)