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Message-ID: <20210819001936.GA5594@linux.alibaba.com>
Date: Thu, 19 Aug 2021 08:19:36 +0800
From: "dust.li" <dust.li@...ux.alibaba.com>
To: Julian Anastasov <ja@....bg>
Cc: Simon Horman <horms@...ge.net.au>,
Wensong Zhang <wensong@...ux-vs.org>,
lvs-devel@...r.kernel.org, netdev@...r.kernel.org,
yunhong-cgl jiang <xintian1976@...il.com>
Subject: Re: [PATCH] net: ipvs: add sysctl_run_estimation to support disable
estimation
On Wed, Aug 18, 2021 at 08:52:11PM +0300, Julian Anastasov wrote:
>
> Hello,
>
>On Wed, 18 Aug 2021, Dust Li wrote:
>
>> fix #31562403
>>
>> estimation_timer will iterater the est_list to do estimation
>> for each ipvs stats. When there are lots of services, the
>> list can be very large.
>> We observiced 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)
>
> I guess, this patch should target net-next tree.
Yes. I will change the patch and send a v2 with net-next prefix.
>
>> Signed-off-by: Dust Li <dust.li@...ux.alibaba.com>
>> ---
>> Documentation/networking/ipvs-sysctl.rst | 17 ++++++
>> include/net/ip_vs.h | 3 +
>> net/netfilter/ipvs/ip_vs_est.c | 73 ++++++++++++++++++++++++
>> 3 files changed, 93 insertions(+)
>>
>> diff --git a/Documentation/networking/ipvs-sysctl.rst b/Documentation/networking/ipvs-sysctl.rst
>> index 2afccc63856e..e20f7a27fc85 100644
>> --- a/Documentation/networking/ipvs-sysctl.rst
>> +++ b/Documentation/networking/ipvs-sysctl.rst
>> @@ -300,3 +300,20 @@ 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.
>> +
>> + For example
>> + 'Conns/s Pkts/s Pkts/s Bytes/s Bytes/s'
>> + those data in /proc/net/ip_vs_stats will always be zero.
>> + Note, this only affect the speed estimation, the total data
>> + will still be updated.
>> +
>> + You can always re-enable estimation by setting this value to 1.
>> + But be carefull, the first estimation after re-enable is not
>> + accurate.
>> diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
>> index d609e957a3ec..6cbb3a08b176 100644
>> --- a/include/net/ip_vs.h
>> +++ b/include/net/ip_vs.h
>> @@ -941,6 +941,9 @@ struct netns_ipvs {
>> struct ctl_table_header *lblcr_ctl_header;
>> struct ctl_table *lblcr_ctl_table;
>> /* ip_vs_est */
>> + int sysctl_run_estimation;
>
> We should keep such sysctl vars in a CONFIG_SYSCTL block
>and we have corresponding inline functions for the two
>cases depending on CONFIG_SYSCTL. Still, many of the sysctl_*
>fields are not moved into such ifdef.
>
> But you can get sysctl_pmtu_disc as example:
>
># grep -r sysctl_pmtu_disc include/net/ip_vs.h net/netfilter/ipvs/
>
> Add the var in ip_vs_ctl.c as the other vars
>and implement it just like sysctl_pmtu_disc.
>
>> + struct ctl_table_header *est_ctl_header;
>> + struct ctl_table *est_ctl_table;
>
> As result, we will not need specific ctl table
OK, will do, thanks for the advice.
>
>> struct list_head est_list; /* estimator list */
>> spinlock_t est_lock;
>> struct timer_list est_timer; /* Estimation timer */
>> diff --git a/net/netfilter/ipvs/ip_vs_est.c b/net/netfilter/ipvs/ip_vs_est.c
>> index 05b8112ffb37..6709796b8621 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 (!ipvs->sysctl_run_estimation)
>> + goto skip;
>
> Some day this var will not be present if !CONFIG_SYSCTL,
>so we should call the new inline function:
>
> if (!sysctl_run_estimation(ipvs))
> goto skip;
Yeah, this is better, will do.
>
>> +
>> 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);
>> }
>>
>> @@ -184,10 +189,77 @@ void ip_vs_read_estimator(struct ip_vs_kstats *dst, struct ip_vs_stats *stats)
>> dst->outbps = (e->outbps + 0xF) >> 5;
>> }
>>
>> +#ifdef CONFIG_SYSCTL
>> +/* IPVS ESTIMATION sysctl table */
>> +static struct ctl_table vs_vars_table[] = {
>> + {
>> + .procname = "run_estimation",
>> + .data = NULL,
>> + .maxlen = sizeof(int),
>> + .mode = 0644,
>> + .proc_handler = proc_dointvec,
>> + },
>> + { }
>> +};
>> +
>> +static int ip_vs_est_sysctl_init(struct netns_ipvs *ipvs)
>> +{
>> + struct net *net = ipvs->net;
>> +
>> + if (!net_eq(net, &init_net)) {
>> + ipvs->est_ctl_table = kmemdup(vs_vars_table,
>> + sizeof(vs_vars_table),
>> + GFP_KERNEL);
>> + if (!ipvs->est_ctl_table)
>> + return -ENOMEM;
>> +
>> + /* Don't export sysctls to unprivileged users */
>> + if (net->user_ns != &init_user_ns)
>> + ipvs->est_ctl_table[0].procname = NULL;
>> +
>> + } else {
>> + ipvs->est_ctl_table = vs_vars_table;
>> + }
>> +
>> + ipvs->sysctl_run_estimation = 1;
>> + ipvs->est_ctl_table[0].data = &ipvs->sysctl_run_estimation;
>> +
>> + ipvs->est_ctl_header =
>> + register_net_sysctl(net, "net/ipv4/vs", ipvs->est_ctl_table);
>> + if (!ipvs->est_ctl_header) {
>> + if (!net_eq(net, &init_net))
>> + kfree(ipvs->est_ctl_table);
>> + return -ENOMEM;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void ip_vs_est_sysctl_cleanup(struct netns_ipvs *ipvs)
>> +{
>> + unregister_net_sysctl_table(ipvs->est_ctl_header);
>> +
>> + if (!net_eq(ipvs->net, &init_net))
>> + kfree(ipvs->est_ctl_table);
>> +}
>> +
>> +#else
>> +
>> +static int ip_vs_est_sysctl_init(struct netns_ipvs *ipvs)
>> +{
>> + ipvs->sysctl_run_estimation = 1;
>> + return 0;
>> +}
>> +
>> +static void ip_vs_est_sysctl_cleanup(struct netns_ipvs *ipvs) { }
>> +
>> +#endif
>
> Drop this ctl table. Just reset sysctl_run_estimation in
>ip_vs_control_net_init_sysctl().
Will do.
>
>> +
>> int __net_init ip_vs_estimator_net_init(struct netns_ipvs *ipvs)
>> {
>> INIT_LIST_HEAD(&ipvs->est_list);
>> spin_lock_init(&ipvs->est_lock);
>> + ip_vs_est_sysctl_init(ipvs);
>> timer_setup(&ipvs->est_timer, estimation_timer, 0);
>> mod_timer(&ipvs->est_timer, jiffies + 2 * HZ);
>> return 0;
>> @@ -196,4 +268,5 @@ int __net_init ip_vs_estimator_net_init(struct netns_ipvs *ipvs)
>> void __net_exit ip_vs_estimator_net_cleanup(struct netns_ipvs *ipvs)
>> {
>> del_timer_sync(&ipvs->est_timer);
>> + ip_vs_est_sysctl_cleanup(ipvs);
>> }
>> --
>> 2.19.1.3.ge56e4f7
>
>Regards
>
>--
>Julian Anastasov <ja@....bg>
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