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tcp: fill shinfo->gso_size at last moment

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In commit cd7d8498c9 ("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>
This commit is contained in:
Eric Dumazet 2015-06-11 09:15:18 -07:00 • committed by David S. Miller
parent 5bbb432c89
commit f69ad292cf
3 changed files with 16 additions and 17 deletions
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13
include/net/tcp.h
View file

@ -730,11 +730,14 @@ struct tcp_skb_cb {
/* 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 @@ static inline void tcp_skb_pcount_add(struct sk_buff *skb, int segs)
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 */