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From:   Chris Packham <Chris.Packham@alliedtelesis.co.nz>
To:     Brodie Greenfield <Brodie.Greenfield@alliedtelesis.co.nz>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "stephen@networkplumber.org" <stephen@networkplumber.org>,
        "kuznet@ms2.inr.ac.ru" <kuznet@ms2.inr.ac.ru>,
        "yoshfuji@linux-ipv6.org" <yoshfuji@linux-ipv6.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Luuk Paulussen" <Luuk.Paulussen@alliedtelesis.co.nz>
Subject: Re: [PATCH 2/2] ip6mr: Make cache queue length configurable
Thread-Topic: [PATCH 2/2] ip6mr: Make cache queue length configurable
Thread-Index: AQHU1FoDNb1gh95Ta0OWaTZ7nknt0w==
Date:   Wed, 6 Mar 2019 20:25:02 +0000
Message-ID: <f78eb1a745a74b81a10db4cc5ce3fb87@svr-chch-ex1.atlnz.lc>
References: <20190306201956.30248-1-brodie.greenfield@alliedtelesis.co.nz>
 <20190306201956.30248-3-brodie.greenfield@alliedtelesis.co.nz>
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On 7/03/19 9:20 AM, Brodie Greenfield wrote:=0A=
> We want to be able to keep more spaces available in our queue for=0A=
> processing incoming IPv6 multicast traffic (adding (S,G) entries) - this=
=0A=
> lets us learn more groups faster, rather than dropping them at this stage=
.=0A=
> =0A=
> Signed-off-by: Brodie Greenfield <brodie.greenfield@alliedtelesis.co.nz>=
=0A=
> ---=0A=
>   Documentation/networking/ip-sysctl.txt | 8 ++++++++=0A=
>   include/net/netns/ipv6.h               | 1 +=0A=
>   net/ipv6/af_inet6.c                    | 1 +=0A=
>   net/ipv6/ip6mr.c                       | 4 +++-=0A=
>   net/ipv6/sysctl_net_ipv6.c             | 7 +++++++=0A=
>   5 files changed, 20 insertions(+), 1 deletion(-)=0A=
> =0A=
> diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/netwo=
rking/ip-sysctl.txt=0A=
> index 02f77e932adf..68eada3ca915 100644=0A=
> --- a/Documentation/networking/ip-sysctl.txt=0A=
> +++ b/Documentation/networking/ip-sysctl.txt=0A=
> @@ -1481,6 +1481,14 @@ skip_notify_on_dev_down - BOOLEAN=0A=
>   	on userspace caches to track link events and evict routes.=0A=
>   	Default: false (generate message)=0A=
>   =0A=
> +ip_mr_cache_queue_length - INTEGER=0A=
=0A=
Should be "ip6_mr_cache_queue_length" for this patch.=0A=
=0A=
> +	Limit the number of multicast packets we can have in the queue to be=0A=
> +	resolved.=0A=
> +	Bear in mind that when an unresolved multicast packet is received,=0A=
> +	there is an O(n) traversal of the queue. This should be considered=0A=
> +	if increasing.=0A=
> +	Default: 10=0A=
> +=0A=
>   IPv6 Fragmentation:=0A=
>   =0A=
>   ip6frag_high_thresh - INTEGER=0A=
> diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h=0A=
> index ef1ed529f33c..84b58424c799 100644=0A=
> --- a/include/net/netns/ipv6.h=0A=
> +++ b/include/net/netns/ipv6.h=0A=
> @@ -46,6 +46,7 @@ struct netns_sysctl_ipv6 {=0A=
>   	int max_hbh_opts_len;=0A=
>   	int seg6_flowlabel;=0A=
>   	bool skip_notify_on_dev_down;=0A=
> +	unsigned int ip6_mr_cache_queue_length;=0A=
>   };=0A=
>   =0A=
>   struct netns_ipv6 {=0A=
> diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c=0A=
> index d99753b5e39b..6551bb63e5a2 100644=0A=
> --- a/net/ipv6/af_inet6.c=0A=
> +++ b/net/ipv6/af_inet6.c=0A=
> @@ -856,6 +856,7 @@ static int __net_init inet6_net_init(struct net *net)=
=0A=
>   	net->ipv6.sysctl.max_hbh_opts_cnt =3D IP6_DEFAULT_MAX_HBH_OPTS_CNT;=0A=
>   	net->ipv6.sysctl.max_dst_opts_len =3D IP6_DEFAULT_MAX_DST_OPTS_LEN;=0A=
>   	net->ipv6.sysctl.max_hbh_opts_len =3D IP6_DEFAULT_MAX_HBH_OPTS_LEN;=0A=
> +	net->ipv6.sysctl.ip6_mr_cache_queue_length =3D 10;=0A=
>   	atomic_set(&net->ipv6.fib6_sernum, 1);=0A=
>   =0A=
>   	err =3D ipv6_init_mibs(net);=0A=
> diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c=0A=
> index cc01aa3f2b5e..bb445871437e 100644=0A=
> --- a/net/ipv6/ip6mr.c=0A=
> +++ b/net/ipv6/ip6mr.c=0A=
> @@ -1135,6 +1135,7 @@ static int ip6mr_cache_report(struct mr_table *mrt,=
 struct sk_buff *pkt,=0A=
>   static int ip6mr_cache_unresolved(struct mr_table *mrt, mifi_t mifi,=0A=
>   				  struct sk_buff *skb, struct net_device *dev)=0A=
>   {=0A=
> +	struct net *net =3D dev_net(dev);=0A=
>   	struct mfc6_cache *c;=0A=
>   	bool found =3D false;=0A=
>   	int err;=0A=
> @@ -1153,7 +1154,8 @@ static int ip6mr_cache_unresolved(struct mr_table *=
mrt, mifi_t mifi,=0A=
>   		 *	Create a new entry if allowable=0A=
>   		 */=0A=
>   =0A=
> -		if (atomic_read(&mrt->cache_resolve_queue_len) >=3D 10 ||=0A=
> +		if (atomic_read(&mrt->cache_resolve_queue_len) >=3D=0A=
> +		    net->ipv6.sysctl.ip6_mr_cache_queue_length ||=0A=
>   		    (c =3D ip6mr_cache_alloc_unres()) =3D=3D NULL) {=0A=
>   			spin_unlock_bh(&mfc_unres_lock);=0A=
>   =0A=
> diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c=0A=
> index e15cd37024fd..a27299d4cc34 100644=0A=
> --- a/net/ipv6/sysctl_net_ipv6.c=0A=
> +++ b/net/ipv6/sysctl_net_ipv6.c=0A=
> @@ -159,6 +159,13 @@ static struct ctl_table ipv6_table_template[] =3D {=
=0A=
>   		.mode		=3D 0644,=0A=
>   		.proc_handler	=3D proc_dointvec=0A=
>   	},=0A=
> +	{=0A=
> +		.procname	=3D "ip6_mr_cache_queue_length",=0A=
> +		.data		=3D &init_net.ipv6.sysctl.ip6_mr_cache_queue_length,=0A=
> +		.maxlen		=3D sizeof(int),=0A=
> +		.mode		=3D 0644,=0A=
> +		.proc_handler	=3D proc_dointvec=0A=
> +	},=0A=
>   	{ }=0A=
>   };=0A=
>   =0A=
> =0A=
=0A=