Merge branch 'netns-speedup-dismantle'

Eric Dumazet says:

====================
netns: speedup netns dismantles

netns are dismantled by a single thread, from cleanup_net()

On hosts with many TCP sockets, and/or many cpus, this thread
is spending too many cpu cycles, and can not keep up with some
workloads.

- Removing 3*num_possible_cpus() sockets per netns, for icmp and tcp protocols.
- Iterating over all TCP sockets to remove stale timewait sockets.

This patch series removes ~50% of cleanup_net() cpu costs on
hosts with 256 cpus. It also reduces per netns memory footprint.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 52 deletions

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 96c5cc0f30ce..e6b978ea0e87 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -69,17 +69,7 @@
 
 #include <linux/uaccess.h>
 
-/*
- *	The ICMP socket(s). This is the most convenient way to flow control
- *	our ICMP output as well as maintain a clean interface throughout
- *	all layers. All Socketless IP sends will soon be gone.
- *
- *	On SMP we have one ICMP socket per-cpu.
- */
-static struct sock *icmpv6_sk(struct net *net)
-{
-	return this_cpu_read(*net->ipv6.icmp_sk);
-}
+static DEFINE_PER_CPU(struct sock *, ipv6_icmp_sk);
 
 static int icmpv6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		       u8 type, u8 code, int offset, __be32 info)
@@ -110,11 +100,11 @@ static const struct inet6_protocol icmpv6_protocol = {
 };
 
 /* Called with BH disabled */
-static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
+static struct sock *icmpv6_xmit_lock(struct net *net)
 {
 	struct sock *sk;
 
-	sk = icmpv6_sk(net);
+	sk = this_cpu_read(ipv6_icmp_sk);
 	if (unlikely(!spin_trylock(&sk->sk_lock.slock))) {
 		/* This can happen if the output path (f.e. SIT or
 		 * ip6ip6 tunnel) signals dst_link_failure() for an
@@ -122,11 +112,13 @@ static __inline__ struct sock *icmpv6_xmit_lock(struct net *net)
 		 */
 		return NULL;
 	}
+	sock_net_set(sk, net);
 	return sk;
 }
 
-static __inline__ void icmpv6_xmit_unlock(struct sock *sk)
+static void icmpv6_xmit_unlock(struct sock *sk)
 {
+	sock_net_set(sk, &init_net);
 	spin_unlock(&sk->sk_lock.slock);
 }
 
@@ -1034,59 +1026,27 @@ void icmpv6_flow_init(struct sock *sk, struct flowi6 *fl6,
 	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
 }
 
-static void __net_exit icmpv6_sk_exit(struct net *net)
-{
-	int i;
-
-	for_each_possible_cpu(i)
-		inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv6.icmp_sk, i));
-	free_percpu(net->ipv6.icmp_sk);
-}
-
-static int __net_init icmpv6_sk_init(struct net *net)
+int __init icmpv6_init(void)
 {
 	struct sock *sk;
 	int err, i;
 
-	net->ipv6.icmp_sk = alloc_percpu(struct sock *);
-	if (!net->ipv6.icmp_sk)
-		return -ENOMEM;
-
 	for_each_possible_cpu(i) {
 		err = inet_ctl_sock_create(&sk, PF_INET6,
-					   SOCK_RAW, IPPROTO_ICMPV6, net);
+					   SOCK_RAW, IPPROTO_ICMPV6, &init_net);
 		if (err < 0) {
 			pr_err("Failed to initialize the ICMP6 control socket (err %d)\n",
 			       err);
-			goto fail;
+			return err;
 		}
 
-		*per_cpu_ptr(net->ipv6.icmp_sk, i) = sk;
+		per_cpu(ipv6_icmp_sk, i) = sk;
 
 		/* Enough space for 2 64K ICMP packets, including
 		 * sk_buff struct overhead.
 		 */
 		sk->sk_sndbuf = 2 * SKB_TRUESIZE(64 * 1024);
 	}
-	return 0;
-
- fail:
-	icmpv6_sk_exit(net);
-	return err;
-}
-
-static struct pernet_operations icmpv6_sk_ops = {
-	.init = icmpv6_sk_init,
-	.exit = icmpv6_sk_exit,
-};
-
-int __init icmpv6_init(void)
-{
-	int err;
-
-	err = register_pernet_subsys(&icmpv6_sk_ops);
-	if (err < 0)
-		return err;
 
 	err = -EAGAIN;
 	if (inet6_add_protocol(&icmpv6_protocol, IPPROTO_ICMPV6) < 0)
@@ -1101,14 +1061,12 @@ sender_reg_err:
 	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 fail:
 	pr_err("Failed to register ICMP6 protocol\n");
-	unregister_pernet_subsys(&icmpv6_sk_ops);
 	return err;
 }
 
 void icmpv6_cleanup(void)
 {
 	inet6_unregister_icmp_sender(icmp6_send);
-	unregister_pernet_subsys(&icmpv6_sk_ops);
 	inet6_del_protocol(&icmpv6_protocol, IPPROTO_ICMPV6);
 }