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| author | Soheil Hassas Yeganeh <soheil@google.com> | 2016-04-27 23:39:01 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-04-28 16:06:10 -0400 |
| commit | 0a2cf20c3fb62ad4717276b5303bf831f7b29d54 (patch) | |
| tree | 8ac718cd55a6ec72241c647e38856d904797a078 /net/ipv4 | |
| parent | 863c1fd9814618eefba02218f8fadf8a430c2a17 (diff) | |
| download | linux-0a2cf20c3fb62ad4717276b5303bf831f7b29d54.tar.gz linux-0a2cf20c3fb62ad4717276b5303bf831f7b29d54.tar.bz2 linux-0a2cf20c3fb62ad4717276b5303bf831f7b29d54.zip | |
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')
| -rw-r--r-- | net/ipv4/tcp.c | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 3 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 17 |
3 files changed, 15 insertions, 10 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); } } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 0d5239c283cb..70c370b93762 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3087,8 +3087,7 @@ static void tcp_ack_tstamp(struct sock *sk, struct sk_buff *skb, return; shinfo = skb_shinfo(skb); - if ((shinfo->tx_flags & SKBTX_ACK_TSTAMP) && - !before(shinfo->tskey, prior_snd_una) && + if (!before(shinfo->tskey, prior_snd_una) && before(shinfo->tskey, tcp_sk(sk)->snd_una)) __skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK); } diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index b1b2045ac3a9..b3a31b4df57c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1111,11 +1111,17 @@ static void tcp_adjust_pcount(struct sock *sk, const struct sk_buff *skb, int de tcp_verify_left_out(tp); } +static bool tcp_has_tx_tstamp(const struct sk_buff *skb) +{ + return TCP_SKB_CB(skb)->txstamp_ack || + (skb_shinfo(skb)->tx_flags & SKBTX_ANY_TSTAMP); +} + static void tcp_fragment_tstamp(struct sk_buff *skb, struct sk_buff *skb2) { struct skb_shared_info *shinfo = skb_shinfo(skb); - if (unlikely(shinfo->tx_flags & SKBTX_ANY_TSTAMP) && + if (unlikely(tcp_has_tx_tstamp(skb)) && !before(shinfo->tskey, TCP_SKB_CB(skb2)->seq)) { struct skb_shared_info *shinfo2 = skb_shinfo(skb2); u8 tsflags = shinfo->tx_flags & SKBTX_ANY_TSTAMP; @@ -2446,13 +2452,12 @@ u32 __tcp_select_window(struct sock *sk) void tcp_skb_collapse_tstamp(struct sk_buff *skb, const struct sk_buff *next_skb) { - const struct skb_shared_info *next_shinfo = skb_shinfo(next_skb); - u8 tsflags = next_shinfo->tx_flags & SKBTX_ANY_TSTAMP; - - if (unlikely(tsflags)) { + if (unlikely(tcp_has_tx_tstamp(next_skb))) { + const struct skb_shared_info *next_shinfo = + skb_shinfo(next_skb); struct skb_shared_info *shinfo = skb_shinfo(skb); - shinfo->tx_flags |= tsflags; + shinfo->tx_flags |= next_shinfo->tx_flags & SKBTX_ANY_TSTAMP; shinfo->tskey = next_shinfo->tskey; TCP_SKB_CB(skb)->txstamp_ack |= TCP_SKB_CB(next_skb)->txstamp_ack; |