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authorSoheil Hassas Yeganeh <soheil@google.com>2016-04-27 23:39:01 -0400
committerDavid S. Miller <davem@davemloft.net>2016-04-28 16:06:10 -0400
commit0a2cf20c3fb62ad4717276b5303bf831f7b29d54 (patch)
tree8ac718cd55a6ec72241c647e38856d904797a078 /net/ipv4/tcp.c
parent863c1fd9814618eefba02218f8fadf8a430c2a17 (diff)
downloadlinux-0a2cf20c3fb62ad4717276b5303bf831f7b29d54.tar.gz
linux-0a2cf20c3fb62ad4717276b5303bf831f7b29d54.tar.xz
tcp: remove SKBTX_ACK_TSTAMP since it is redundant
The SKBTX_ACK_TSTAMP flag is set in skb_shinfo->tx_flags when the timestamp of the TCP acknowledgement should be reported on error queue. Since accessing skb_shinfo is likely to incur a cache-line miss at the time of receiving the ack, the txstamp_ack bit was added in tcp_skb_cb, which is set iff the SKBTX_ACK_TSTAMP flag is set for an skb. This makes SKBTX_ACK_TSTAMP flag redundant. Remove the SKBTX_ACK_TSTAMP and instead use the txstamp_ack bit everywhere. Note that this frees one bit in shinfo->tx_flags. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Suggested-by: Willem de Bruijn <willemb@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
-rw-r--r--net/ipv4/tcp.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 53890a730ff4..91993782a947 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -435,9 +435,10 @@ static void tcp_tx_timestamp(struct sock *sk, u16 tsflags, struct sk_buff *skb)
struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
- if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
+ if (tsflags & SOF_TIMESTAMPING_TX_ACK)
+ tcb->txstamp_ack = 1;
+ if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
- tcb->txstamp_ack = !!(shinfo->tx_flags & SKBTX_ACK_TSTAMP);
}
}