| Message ID | 1461620690-1081063-3-git-send-email-kafai@fb.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, 2016-04-25 at 14:44 -0700, Martin KaFai Lau wrote: > This patch: > 1. Prevent next_skb from coalescing to the prev_skb if > TCP_SKB_CB(prev_skb)->eor is set > 2. Update the TCP_SKB_CB(prev_skb)->eor if coalescing is > allowed Acked-by: Eric Dumazet <edumazet@google.com>
On Mon, Apr 25, 2016 at 5:44 PM, Martin KaFai Lau <kafai@fb.com> wrote: > This patch: > 1. Prevent next_skb from coalescing to the prev_skb if > TCP_SKB_CB(prev_skb)->eor is set > 2. Update the TCP_SKB_CB(prev_skb)->eor if coalescing is > allowed > > Packetdrill script for testing: > ~~~~~~ > +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` > +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` > +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 > +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 > +0 bind(3, ..., ...) = 0 > +0 listen(3, 1) = 0 > > 0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> > 0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> > 0.200 < . 1:1(0) ack 1 win 257 > 0.200 accept(3, ..., ...) = 4 > +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 > > 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 > 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 > 0.200 write(4, ..., 11680) = 11680 > > 0.200 > P. 1:731(730) ack 1 > 0.200 > P. 731:1461(730) ack 1 > 0.200 > . 1461:8761(7300) ack 1 > 0.200 > P. 8761:13141(4380) ack 1 > > 0.300 < . 1:1(0) ack 1 win 257 <sack 1461:13141,nop,nop> > 0.300 > P. 1:731(730) ack 1 > 0.300 > P. 731:1461(730) ack 1 > 0.400 < . 1:1(0) ack 13141 win 257 > > 0.400 close(4) = 0 > 0.400 > F. 13141:13141(0) ack 1 > 0.500 < F. 1:1(0) ack 13142 win 257 > 0.500 > . 13142:13142(0) ack 2 > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > Cc: Eric Dumazet <edumazet@google.com> > Cc: Neal Cardwell <ncardwell@google.com> > Cc: Soheil Hassas Yeganeh <soheil@google.com> > Cc: Willem de Bruijn <willemb@google.com> > Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> > --- > net/ipv4/tcp_input.c | 4 ++++ > net/ipv4/tcp_output.c | 4 ++++ > 2 files changed, 8 insertions(+) > > diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c > index dcad8f9..65fb708 100644 > --- a/net/ipv4/tcp_input.c > +++ b/net/ipv4/tcp_input.c > @@ -1303,6 +1303,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, > } > > TCP_SKB_CB(prev)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags; > + TCP_SKB_CB(prev)->eor = TCP_SKB_CB(skb)->eor; > if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) > TCP_SKB_CB(prev)->end_seq++; > > @@ -1368,6 +1369,9 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, > if ((TCP_SKB_CB(prev)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) > goto fallback; > > + if (!tcp_skb_can_collapse_to(prev)) > + goto fallback; > + > in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && > !before(end_seq, TCP_SKB_CB(skb)->end_seq); > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > index 9d3b4b3..fa4d17f 100644 > --- a/net/ipv4/tcp_output.c > +++ b/net/ipv4/tcp_output.c > @@ -2494,6 +2494,7 @@ static void tcp_collapse_retrans(struct sock *sk, struct sk_buff *skb) > * packet counting does not break. > */ > TCP_SKB_CB(skb)->sacked |= TCP_SKB_CB(next_skb)->sacked & TCPCB_EVER_RETRANS; > + TCP_SKB_CB(skb)->eor = TCP_SKB_CB(next_skb)->eor; > > /* changed transmit queue under us so clear hints */ > tcp_clear_retrans_hints_partial(tp); > @@ -2545,6 +2546,9 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *to, > if (!tcp_can_collapse(sk, skb)) > break; > > + if (!tcp_skb_can_collapse_to(to)) > + break; > + > space -= skb->len; > > if (first) { > -- > 2.5.1 >
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index dcad8f9..65fb708 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1303,6 +1303,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb, } TCP_SKB_CB(prev)->tcp_flags |= TCP_SKB_CB(skb)->tcp_flags; + TCP_SKB_CB(prev)->eor = TCP_SKB_CB(skb)->eor; if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) TCP_SKB_CB(prev)->end_seq++; @@ -1368,6 +1369,9 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb, if ((TCP_SKB_CB(prev)->sacked & TCPCB_TAGBITS) != TCPCB_SACKED_ACKED) goto fallback; + if (!tcp_skb_can_collapse_to(prev)) + goto fallback; + in_sack = !after(start_seq, TCP_SKB_CB(skb)->seq) && !before(end_seq, TCP_SKB_CB(skb)->end_seq); diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 9d3b4b3..fa4d17f 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2494,6 +2494,7 @@ static void tcp_collapse_retrans(struct sock *sk, struct sk_buff *skb) * packet counting does not break. */ TCP_SKB_CB(skb)->sacked |= TCP_SKB_CB(next_skb)->sacked & TCPCB_EVER_RETRANS; + TCP_SKB_CB(skb)->eor = TCP_SKB_CB(next_skb)->eor; /* changed transmit queue under us so clear hints */ tcp_clear_retrans_hints_partial(tp); @@ -2545,6 +2546,9 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *to, if (!tcp_can_collapse(sk, skb)) break; + if (!tcp_skb_can_collapse_to(to)) + break; + space -= skb->len; if (first) {
This patch: 1. Prevent next_skb from coalescing to the prev_skb if TCP_SKB_CB(prev_skb)->eor is set 2. Update the TCP_SKB_CB(prev_skb)->eor if coalescing is allowed Packetdrill script for testing: ~~~~~~ +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> 0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> 0.200 < . 1:1(0) ack 1 win 257 0.200 accept(3, ..., ...) = 4 +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 write(4, ..., 11680) = 11680 0.200 > P. 1:731(730) ack 1 0.200 > P. 731:1461(730) ack 1 0.200 > . 1461:8761(7300) ack 1 0.200 > P. 8761:13141(4380) ack 1 0.300 < . 1:1(0) ack 1 win 257 <sack 1461:13141,nop,nop> 0.300 > P. 1:731(730) ack 1 0.300 > P. 731:1461(730) ack 1 0.400 < . 1:1(0) ack 13141 win 257 0.400 close(4) = 0 0.400 > F. 13141:13141(0) ack 1 0.500 < F. 1:1(0) ack 13142 win 257 0.500 > . 13142:13142(0) ack 2 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Yuchung Cheng <ycheng@google.com> --- net/ipv4/tcp_input.c | 4 ++++ net/ipv4/tcp_output.c | 4 ++++ 2 files changed, 8 insertions(+)