diff options
| author | David S. Miller <davem@davemloft.net> | 2024-04-25 08:52:12 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2024-04-25 08:52:12 +0100 |
| commit | caf93883f623ebd29989e3c35423f386ea4a41bb (patch) | |
| tree | 3e523116c5e7de8d0a426fa022f7a4c13966e453 /net/ipv4/tcp_output.c | |
| parent | d806871612712f1d08eb7ce81efd4ca81ca5bca1 (diff) | |
| parent | 2bf90a57f0e682872c5cfb66ffa45e432bb9c7ae (diff) | |
Merge branch 'tcp-trace-next'
Philo Lu says:
====================
tcp: update TCPCB_EVER_RETRANS after trace_tcp_retransmit_skb()
Move TCPCB_EVER_RETRANS updating after the trace_tcp_retransmit_skb()
in __tcp_retransmit_skb(), and then we are aware of whether the skb has
ever been retransmitted in this tracepoint. This can be used, e.g., to get
retransmission efficiency by counting skbs w/ and w/o TCPCB_EVER_RETRANS
(through bpf tracing programs).
For this purpose, TCPCB_EVER_RETRANS is also needed to be exposed to bpf.
Previously, the flags are defined as macros in struct tcp_skb_cb. I moved them
out into a new enum, and then they can be accessed with vmlinux.h.
We have discussed to achieve this with BPF_SOCK_OPS in [0], and using
tracepoint is thought to be a better solution.
[0]
https://lore.kernel.org/all/20240417124622.35333-1-lulie@linux.alibaba.com/
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 99a1d88f7f47..ce59e4499b66 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3418,11 +3418,6 @@ start: err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC); } - /* To avoid taking spuriously low RTT samples based on a timestamp - * for a transmit that never happened, always mark EVER_RETRANS - */ - TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS; - if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RETRANS_CB_FLAG)) tcp_call_bpf_3arg(sk, BPF_SOCK_OPS_RETRANS_CB, TCP_SKB_CB(skb)->seq, segs, err); @@ -3432,6 +3427,12 @@ start: } else if (err != -EBUSY) { NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL, segs); } + + /* To avoid taking spuriously low RTT samples based on a timestamp + * for a transmit that never happened, always mark EVER_RETRANS + */ + TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS; + return err; } |