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/include/net/tcp.h b/include/net/tcp.h
index 978cebe..950cfec 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -730,11 +730,14 @@
/* Note : tcp_tw_isn is used in input path only
* (isn chosen by tcp_timewait_state_process())
*
- * tcp_gso_segs is used in write queue only,
- * cf tcp_skb_pcount()
+ * tcp_gso_segs/size are used in write queue only,
+ * cf tcp_skb_pcount()/tcp_skb_mss()
*/
__u32 tcp_tw_isn;
- __u32 tcp_gso_segs;
+ struct {
+ u16 tcp_gso_segs;
+ u16 tcp_gso_size;
+ };
};
__u8 tcp_flags; /* TCP header flags. (tcp[13]) */
@@ -790,10 +793,10 @@
TCP_SKB_CB(skb)->tcp_gso_segs += segs;
}
-/* This is valid iff tcp_skb_pcount() > 1. */
+/* This is valid iff skb is in write queue and tcp_skb_pcount() > 1. */
static inline int tcp_skb_mss(const struct sk_buff *skb)
{
- return skb_shinfo(skb)->gso_size;
+ return TCP_SKB_CB(skb)->tcp_gso_size;
}
/* Events passed to congestion control interface */