linux/net/netfilter/ipvs
Julian Anastasov f0a5e4d7a5 ipvs: allow connection reuse for unconfirmed conntrack
YangYuxi is reporting that connection reuse
is causing one-second delay when SYN hits
existing connection in TIME_WAIT state.
Such delay was added to give time to expire
both the IPVS connection and the corresponding
conntrack. This was considered a rare case
at that time but it is causing problem for
some environments such as Kubernetes.

As nf_conntrack_tcp_packet() can decide to
release the conntrack in TIME_WAIT state and
to replace it with a fresh NEW conntrack, we
can use this to allow rescheduling just by
tuning our check: if the conntrack is
confirmed we can not schedule it to different
real server and the one-second delay still
applies but if new conntrack was created,
we are free to select new real server without
any delays.

YangYuxi lists some of the problem reports:

- One second connection delay in masquerading mode:
https://marc.info/?t=151683118100004&r=1&w=2

- IPVS low throughput #70747
https://github.com/kubernetes/kubernetes/issues/70747

- Apache Bench can fill up ipvs service proxy in seconds #544
https://github.com/cloudnativelabs/kube-router/issues/544

- Additional 1s latency in `host -> service IP -> pod`
https://github.com/kubernetes/kubernetes/issues/90854

Fixes: f719e3754e ("ipvs: drop first packet to redirect conntrack")
Co-developed-by: YangYuxi <yx.atom1@gmail.com>
Signed-off-by: YangYuxi <yx.atom1@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2020-07-04 01:18:37 +02:00
..
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile netfilter: ipvs: Add configurations of Maglev hashing 2018-04-09 10:11:18 +03:00
ip_vs_app.c ipvs: don't ignore errors in case refcounting ip_vs module fails 2019-10-24 11:53:19 +02:00
ip_vs_conn.c ipvs: avoid expiring many connections from timer 2020-07-01 10:18:20 +02:00
ip_vs_core.c ipvs: allow connection reuse for unconfirmed conntrack 2020-07-04 01:18:37 +02:00
ip_vs_ctl.c ipvs: avoid expiring many connections from timer 2020-07-01 10:18:20 +02:00
ip_vs_dh.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_est.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_fo.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_ftp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-07 11:00:14 -07:00
ip_vs_lblc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_lblcr.c net: delete "register" keyword 2019-08-08 18:03:42 -07:00
ip_vs_lc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_mh.c netfilter: remove unnecessary spaces 2019-08-13 12:08:48 +02:00
ip_vs_nfct.c netfilter: nf_conntrack_sip: fix expectation clash 2019-07-16 13:16:59 +02:00
ip_vs_nq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_ovf.c net: Fix various misspellings of "connect" 2019-10-28 13:41:59 -07:00
ip_vs_pe.c ipvs: don't ignore errors in case refcounting ip_vs module fails 2019-10-24 11:53:19 +02:00
ip_vs_pe_sip.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
ip_vs_proto.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_proto_ah_esp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
ip_vs_proto_sctp.c netfilter: ipvs: prefer skb_ensure_writable 2019-05-31 18:02:44 +02:00
ip_vs_proto_tcp.c netfilter: remove unnecessary spaces 2019-08-13 12:08:48 +02:00
ip_vs_proto_udp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-07 11:00:14 -07:00
ip_vs_rr.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_sched.c ipvs: don't ignore errors in case refcounting ip_vs module fails 2019-10-24 11:53:19 +02:00
ip_vs_sed.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_sh.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_sync.c ipvs: fix spelling mistake "to" -> "too" 2020-01-24 08:12:06 +01:00
ip_vs_wlc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_wrr.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
ip_vs_xmit.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2019-12-24 22:28:54 -08:00