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>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index d128885..787f57f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -402,8 +402,6 @@
*/
static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags)
{
- struct skb_shared_info *shinfo = skb_shinfo(skb);
-
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum = 0;
@@ -411,7 +409,6 @@
TCP_SKB_CB(skb)->sacked = 0;
tcp_skb_pcount_set(skb, 1);
- shinfo->gso_size = 0;
TCP_SKB_CB(skb)->seq = seq;
if (flags & (TCPHDR_SYN | TCPHDR_FIN))
@@ -1028,8 +1025,9 @@
tcp_skb_pcount(skb));
tp->segs_out += tcp_skb_pcount(skb);
- /* OK, its time to fill skb_shinfo(skb)->gso_segs */
+ /* OK, its time to fill skb_shinfo(skb)->gso_{segs|size} */
skb_shinfo(skb)->gso_segs = tcp_skb_pcount(skb);
+ skb_shinfo(skb)->gso_size = tcp_skb_mss(skb);
/* Our usage of tstamp should remain private */
skb->tstamp.tv64 = 0;
@@ -1068,8 +1066,6 @@
/* Initialize TSO segments for a packet. */
static void tcp_set_skb_tso_segs(struct sk_buff *skb, unsigned int mss_now)
{
- struct skb_shared_info *shinfo = skb_shinfo(skb);
-
/* Make sure we own this skb before messing gso_size/gso_segs */
WARN_ON_ONCE(skb_cloned(skb));
@@ -1078,10 +1074,10 @@
* non-TSO case.
*/
tcp_skb_pcount_set(skb, 1);
- shinfo->gso_size = 0;
+ TCP_SKB_CB(skb)->tcp_gso_size = 0;
} else {
tcp_skb_pcount_set(skb, DIV_ROUND_UP(skb->len, mss_now));
- shinfo->gso_size = mss_now;
+ TCP_SKB_CB(skb)->tcp_gso_size = mss_now;
}
}