[PATCH nf-next 01/15] ipvs: add sysctl_run_estimation to support disable estimation

STALE1818d REVIEWED: 2 (2M)

From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2021-10-17 22:15:45
Also in: netfilter-devel
Subsystem: documentation, ipvs, netfilter, networking [general], networking [ipv4/ipv6], the rest · Maintainers: Jonathan Corbet, Simon Horman, Julian Anastasov, Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds

Revision v1 of 38 in this series; 2 review trailers (2 from subsystem maintainers).

Revisions (38)

2013-06-05 v1
2013-08-20 v1
2013-11-04 v1
2014-01-05 v1
2014-03-17 v1
2014-05-29 v1
2014-10-03 v1
2014-11-24 v1
2015-09-22 v1
2016-07-23 v1
2016-07-23 v1
2017-05-01 v1
2017-11-07 v1
2018-01-08 v1
2018-01-19 v1
2018-03-12 v1
2018-05-06 v1
2018-06-02 v1
2019-02-17 v1
2019-03-02 v1
2019-04-15 v1
2019-06-01 v1
2019-07-08 v1
2019-10-26 v1
2020-03-30 v1
2020-03-30 v1
2020-10-12 v1
2020-12-12 v1
2021-02-06 v1
2021-10-17 v1 current
2022-07-20 v1
2023-04-21 v1
2023-04-21 v1
2024-06-27 v1
2024-06-28 v1
2026-06-07 v1
2026-06-14 v1
2026-07-24 v1

From: Dust Li <dust.li@linux.alibaba.com>

estimation_timer will iterate the est_list to do estimation
for each ipvs stats. When there are lots of services, the
list can be very large.
We found that estimation_timer() run for more then 200ms on a
machine with 104 CPU and 50K services.

yunhong-cgl jiang report the same phenomenon before:
https://www.spinics.net/lists/lvs-devel/msg05426.html

In some cases(for example a large K8S cluster with many ipvs services),
ipvs estimation may not be needed. So adding a sysctl blob to allow
users to disable this completely.

Default is: 1 (enable)

Cc: yunhong-cgl jiang <redacted>
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 Documentation/networking/ipvs-sysctl.rst | 11 +++++++++++
 include/net/ip_vs.h                      | 11 +++++++++++
 net/netfilter/ipvs/ip_vs_ctl.c           |  8 ++++++++
 net/netfilter/ipvs/ip_vs_est.c           |  5 +++++
 4 files changed, 35 insertions(+)

diff --git a/Documentation/networking/ipvs-sysctl.rst b/Documentation/networking/ipvs-sysctl.rst
index 2afccc63856e..95ef56d62077 100644
--- a/Documentation/networking/ipvs-sysctl.rst
+++ b/Documentation/networking/ipvs-sysctl.rst

@@ -300,3 +300,14 @@ sync_version - INTEGER
 
 	Kernels with this sync_version entry are able to receive messages
 	of both version 1 and version 2 of the synchronisation protocol.
+
+run_estimation - BOOLEAN
+	0 - disabled
+	not 0 - enabled (default)
+
+	If disabled, the estimation will be stop, and you can't see
+	any update on speed estimation data.
+
+	You can always re-enable estimation by setting this value to 1.
+	But be careful, the first estimation after re-enable is not
+	accurate.

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 7cb5a1aace40..ff1804a0c469 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h

@@ -931,6 +931,7 @@ struct netns_ipvs {
 	int			sysctl_conn_reuse_mode;
 	int			sysctl_schedule_icmp;
 	int			sysctl_ignore_tunneled;
+	int			sysctl_run_estimation;
 
 	/* ip_vs_lblc */
 	int			sysctl_lblc_expiration;

@@ -1071,6 +1072,11 @@ static inline int sysctl_cache_bypass(struct netns_ipvs *ipvs)
 	return ipvs->sysctl_cache_bypass;
 }
 
+static inline int sysctl_run_estimation(struct netns_ipvs *ipvs)
+{
+	return ipvs->sysctl_run_estimation;
+}
+
 #else
 
 static inline int sysctl_sync_threshold(struct netns_ipvs *ipvs)

@@ -1163,6 +1169,11 @@ static inline int sysctl_cache_bypass(struct netns_ipvs *ipvs)
 	return 0;
 }
 
+static inline int sysctl_run_estimation(struct netns_ipvs *ipvs)
+{
+	return 1;
+}
+
 #endif
 
 /* IPVS core functions

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index c25097092a06..cbea5a68afb5 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c

@@ -2017,6 +2017,12 @@ static struct ctl_table vs_vars[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	{
+		.procname	= "run_estimation",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
 #ifdef CONFIG_IP_VS_DEBUG
 	{
 		.procname	= "debug_level",

@@ -4090,6 +4096,8 @@ static int __net_init ip_vs_control_net_init_sysctl(struct netns_ipvs *ipvs)
 	tbl[idx++].data = &ipvs->sysctl_conn_reuse_mode;
 	tbl[idx++].data = &ipvs->sysctl_schedule_icmp;
 	tbl[idx++].data = &ipvs->sysctl_ignore_tunneled;
+	ipvs->sysctl_run_estimation = 1;
+	tbl[idx++].data = &ipvs->sysctl_run_estimation;
 
 	ipvs->sysctl_hdr = register_net_sysctl(net, "net/ipv4/vs", tbl);
 	if (ipvs->sysctl_hdr == NULL) {

diff --git a/net/netfilter/ipvs/ip_vs_est.c b/net/netfilter/ipvs/ip_vs_est.c
index 05b8112ffb37..9a1a7af6a186 100644
--- a/net/netfilter/ipvs/ip_vs_est.c
+++ b/net/netfilter/ipvs/ip_vs_est.c

@@ -100,6 +100,9 @@ static void estimation_timer(struct timer_list *t)
 	u64 rate;
 	struct netns_ipvs *ipvs = from_timer(ipvs, t, est_timer);
 
+	if (!sysctl_run_estimation(ipvs))
+		goto skip;
+
 	spin_lock(&ipvs->est_lock);
 	list_for_each_entry(e, &ipvs->est_list, list) {
 		s = container_of(e, struct ip_vs_stats, est);

@@ -131,6 +134,8 @@ static void estimation_timer(struct timer_list *t)
 		spin_unlock(&s->lock);
 	}
 	spin_unlock(&ipvs->est_lock);
+
+skip:
 	mod_timer(&ipvs->est_timer, jiffies + 2*HZ);
 }

-- 
2.30.2

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