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authorEric Dumazet <edumazet@google.com>2015-06-11 09:15:18 -0700
committerDavid S. Miller <davem@davemloft.net>2015-06-11 16:33:11 -0700
commitf69ad292cfd13aa7ee00847320c6bb9ba2154e87 (patch)
tree7158b39eda3c315797407b0d558f7d301196499e /net
parent5bbb432c896d23ce8f41f38e88dbd38982df99f9 (diff)
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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c8
-rw-r--r--net/ipv4/tcp_output.c12
2 files changed, 8 insertions, 12 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)
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;
}
}

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