From f69ad292cfd13aa7ee00847320c6bb9ba2154e87 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 11 Jun 2015 09:15:18 -0700 Subject: 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 Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'net/ipv4/tcp_output.c') diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index d12888581337..787f57ff87c4 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -402,8 +402,6 @@ static void tcp_ecn_send(struct sock *sk, struct sk_buff *skb, */ 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 @@ static void tcp_init_nondata_skb(struct sk_buff *skb, u32 seq, u8 flags) 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 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it, 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 @@ static void tcp_queue_skb(struct sock *sk, struct sk_buff *skb) /* 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 @@ static void tcp_set_skb_tso_segs(struct sk_buff *skb, unsigned int mss_now) * 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; } } -- cgit v1.2.3