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Date: Wed, 28 Feb 2018 11:19:56 -0800
From: Stephen Hemminger <stephen@...workplumber.org>
To: Tonghao Zhang <xiangxia.m.yue@...il.com>
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH] tcp: Support tcp socket allocated counter in namespace.
On Mon, 12 Feb 2018 18:44:00 -0800
Tonghao Zhang <xiangxia.m.yue@...il.com> wrote:
> Sometimes, we want to know how many tcp sockets are in use
> different _net_ namespaces. It's a key resource metric. With
> this patch, we can get it via /proc/net/sockstat.
>
> The 'alloc' show in /proc/net/sockstat is the total tcp
> sockets in the kernel. This patch moves it to namespace,
> via adding a counter because the previous counter is used
> in proto(e.g tcp, udp and sctp) memory management.
>
> Signed-off-by: Tonghao Zhang <xiangxia.m.yue@...il.com>
> ---
> include/net/netns/ipv4.h | 3 +++
> include/net/tcp.h | 2 ++
> net/ipv4/proc.c | 2 +-
> net/ipv4/tcp.c | 2 ++
> net/ipv4/tcp_ipv4.c | 34 ++++++++++++++++++++++++++++++++++
> net/ipv4/tcp_minisocks.c | 3 +++
> 6 files changed, 45 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
> index 44668c2..85e91bd 100644
> --- a/include/net/netns/ipv4.h
> +++ b/include/net/netns/ipv4.h
> @@ -68,6 +68,9 @@ struct netns_ipv4 {
>
> struct inet_peer_base *peers;
> struct sock * __percpu *tcp_sk;
> +#ifdef CONFIG_PROC_FS
> + int __percpu *tcp_sock_allocated;
> +#endif
> struct netns_frags frags;
> #ifdef CONFIG_NETFILTER
> struct xt_table *iptable_filter;
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 093e967..4b24b6e 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -1780,6 +1780,8 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
> int tcp_gro_complete(struct sk_buff *skb);
>
> void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr);
> +void tcp_sock_allocated_add(struct net *net, int val);
> +int tcp_sock_allocated_get(struct net *net);
>
> static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)
> {
> diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
> index dc5edc8..8a147f7 100644
> --- a/net/ipv4/proc.c
> +++ b/net/ipv4/proc.c
> @@ -58,7 +58,7 @@ static int sockstat_seq_show(struct seq_file *seq, void *v)
> int orphans, sockets;
>
> orphans = percpu_counter_sum_positive(&tcp_orphan_count);
> - sockets = proto_sockets_allocated_sum_positive(&tcp_prot);
> + sockets = tcp_sock_allocated_get(net);
>
> socket_seq_show(seq);
> seq_printf(seq, "TCP: inuse %d orphan %d tw %d alloc %d mem %ld\n",
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 874c931..77fe4a5 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -453,6 +453,8 @@ void tcp_init_sock(struct sock *sk)
> sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
>
> sk_sockets_allocated_inc(sk);
> + if (likely(sk->sk_net_refcnt))
> + tcp_sock_allocated_add(sock_net(sk), 1);
> }
> EXPORT_SYMBOL(tcp_init_sock);
>
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index 95738aa..a7bd0c4 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -1928,6 +1928,8 @@ void tcp_v4_destroy_sock(struct sock *sk)
> tcp_saved_syn_free(tp);
>
> sk_sockets_allocated_dec(sk);
> + if (likely(sk->sk_net_refcnt))
> + tcp_sock_allocated_add(sock_net(sk), -1);
> }
> EXPORT_SYMBOL(tcp_v4_destroy_sock);
>
> @@ -2446,6 +2448,28 @@ struct proto tcp_prot = {
> };
> EXPORT_SYMBOL(tcp_prot);
>
> +void tcp_sock_allocated_add(struct net *net, int val)
> +{
> +#ifdef CONFIG_PROC_FS
> + this_cpu_add(*net->ipv4.tcp_sock_allocated, val);
> +#endif
> +}
> +EXPORT_SYMBOL(tcp_sock_allocated_add);
> +
> +int tcp_sock_allocated_get(struct net *net)
> +{
> +#ifdef CONFIG_PROC_FS
> + int cpu, res = 0;
> +
> + for_each_possible_cpu(cpu)
> + res += *per_cpu_ptr(net->ipv4.tcp_sock_allocated, cpu);
> + return res;
> +#else
> + return 0;
> +#endif
> +}
> +EXPORT_SYMBOL(tcp_sock_allocated_get);
> +
> static void __net_exit tcp_sk_exit(struct net *net)
> {
> int cpu;
> @@ -2455,6 +2479,10 @@ static void __net_exit tcp_sk_exit(struct net *net)
> for_each_possible_cpu(cpu)
> inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu));
> free_percpu(net->ipv4.tcp_sk);
> +
> +#ifdef CONFIG_PROC_FS
> + free_percpu(net->ipv4.tcp_sock_allocated);
> +#endif
> }
>
> static int __net_init tcp_sk_init(struct net *net)
> @@ -2465,6 +2493,12 @@ static int __net_init tcp_sk_init(struct net *net)
> if (!net->ipv4.tcp_sk)
> return -ENOMEM;
>
> +#ifdef CONFIG_PROC_FS
> + net->ipv4.tcp_sock_allocated = alloc_percpu(int);
> + if (!net->ipv4.tcp_sock_allocated)
> + goto fail;
> +#endif
> +
> for_each_possible_cpu(cpu) {
> struct sock *sk;
>
> diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
> index a8384b0c..573fe43 100644
> --- a/net/ipv4/tcp_minisocks.c
> +++ b/net/ipv4/tcp_minisocks.c
> @@ -559,6 +559,9 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
> newtp->rack.reo_wnd_persist = 0;
> newtp->rack.dsack_seen = 0;
>
> + if (likely(newsk->sk_net_refcnt))
> + tcp_sock_allocated_add(sock_net(newsk), 1);
> +
> __TCP_INC_STATS(sock_net(sk), TCP_MIB_PASSIVEOPENS);
> }
> return newsk;
This makes sense to me only if you get rid of the old tcp_sockets_allocated and
the proto field entry for .sockets_allocated. In that case you are replacing a global
counter with a per-namespace counter and the impact should be minimal.
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