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| author | Lawrence Brakmo <brakmo@fb.com> | 2016-09-27 19:03:37 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-28 07:52:34 -0400 |
| commit | 3acf3ec3f4b0fd4263989f2e4227bbd1c42b5fe1 (patch) | |
| tree | cdc67656dc5d6ea9bc76ed3e2cd80b3614065d8d /net/ipv4 | |
| parent | fa5effe7664b1606dfd639dff58686f6dbb119d7 (diff) | |
| download | linux-3acf3ec3f4b0fd4263989f2e4227bbd1c42b5fe1.tar.gz linux-3acf3ec3f4b0fd4263989f2e4227bbd1c42b5fe1.tar.bz2 linux-3acf3ec3f4b0fd4263989f2e4227bbd1c42b5fe1.zip | |
tcp: Change txhash on every SYN and RTO retransmit
The current code changes txhash (flowlables) on every retransmitted
SYN/ACK, but only after the 2nd retransmitted SYN and only after
tcp_retries1 RTO retransmits.
With this patch:
1) txhash is changed with every SYN retransmits
2) txhash is changed with every RTO.
The result is that we can start re-routing around failed (or very
congested paths) as soon as possible. Otherwise application health
checks may fail and the connection may be terminated before we start
to change txhash.
v4: Removed sysctl, txhash is changed for all RTOs
v3: Removed text saying default value of sysctl is 0 (it is 100)
v2: Added sysctl documentation and cleaned code
Tested with packetdrill tests
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_timer.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index f712b411f6ed..3ea1cf804748 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -192,6 +192,8 @@ static int tcp_write_timeout(struct sock *sk) if (tp->syn_data && icsk->icsk_retransmits == 1) NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENACTIVEFAIL); + } else if (!tp->syn_data && !tp->syn_fastopen) { + sk_rethink_txhash(sk); } retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; syn_set = true; @@ -213,6 +215,8 @@ static int tcp_write_timeout(struct sock *sk) tcp_mtu_probing(icsk, sk); dst_negative_advice(sk); + } else { + sk_rethink_txhash(sk); } retry_until = net->ipv4.sysctl_tcp_retries2; |