diff options
| author |   Eric Dumazet <edumazet@google.com> | 2018-11-11 06:41:30 -0800 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-11-11 13:54:53 -0800 |
| commit | f1c6ea3827b5e5ec62e297bcf4ccfd065326e8f7 (patch) | |
| tree | 69036d0cdbfb568233a8838bc1ff9f9b29ab624b /net | |
| parent | tcp: do not try to defer skbs with eor mark (MSG_EOR) (diff) | |
| download | linux-dev-f1c6ea3827b5e5ec62e297bcf4ccfd065326e8f7.tar.xz linux-dev-f1c6ea3827b5e5ec62e297bcf4ccfd065326e8f7.zip | |
tcp: refine tcp_tso_should_defer() after EDT adoption
tcp_tso_should_defer() last step tries to check if the probable
next ACK packet is coming in less than half rtt.
Problem is that the head->tstamp might be in the future,
so we need to use signed arithmetics to avoid overflows.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_output.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 35feadf48030..78a56cef7e39 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1907,10 +1907,11 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb, bool *is_cwnd_limited, u32 max_segs) { const struct inet_connection_sock *icsk = inet_csk(sk); - u32 age, send_win, cong_win, limit, in_flight; + u32 send_win, cong_win, limit, in_flight; struct tcp_sock *tp = tcp_sk(sk); struct sk_buff *head; int win_divisor; + s64 delta; if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) goto send_now; @@ -1972,9 +1973,9 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb, head = tcp_rtx_queue_head(sk); if (!head) goto send_now; - age = tcp_stamp_us_delta(tp->tcp_mstamp, tcp_skb_timestamp_us(head)); + delta = tp->tcp_clock_cache - head->tstamp; /* If next ACK is likely to come too late (half srtt), do not defer */ - if (age < (tp->srtt_us >> 4)) + if ((s64)(delta - (u64)NSEC_PER_USEC * (tp->srtt_us >> 4)) < 0) goto send_now; /* Ok, it looks like it is advisable to defer. */ |