path: root/net/ipv4/ip_tunnel.c
diff options
authorEric Dumazet <edumazet@google.com>2018-03-08 12:51:41 -0800
committerDavid S. Miller <davem@davemloft.net>2018-03-09 11:23:11 -0500
commit79134e6ce2c9d1a00eab4d98cb48f975dd2474cb (patch)
treeb5f8a1d1f2036315e6955d015fd181c538ed8ebf /net/ipv4/ip_tunnel.c
parenttools: tc-testing: Can pause just before post-suite (diff)
net: do not create fallback tunnels for non-default namespaces
fallback tunnels (like tunl0, gre0, gretap0, erspan0, sit0, ip6tnl0, ip6gre0) are automatically created when the corresponding module is loaded. These tunnels are also automatically created when a new network namespace is created, at a great cost. In many cases, netns are used for isolation purposes, and these extra network devices are a waste of resources. We are using thousands of netns per host, and hit the netns creation/delete bottleneck a lot. (Many thanks to Kirill for recent work on this) Add a new sysctl so that we can opt-out from this automatic creation. Note that these tunnels are still created for the initial namespace, to be the least intrusive for typical setups. Tested: lpk43:~# cat add_del_unshare.sh for i in `seq 1 40` do (for j in `seq 1 100` ; do unshare -n /bin/true >/dev/null ; done) & done wait lpk43:~# echo 0 >/proc/sys/net/core/fb_tunnels_only_for_init_net lpk43:~# time ./add_del_unshare.sh real 0m37.521s user 0m0.886s sys 7m7.084s lpk43:~# echo 1 >/proc/sys/net/core/fb_tunnels_only_for_init_net lpk43:~# time ./add_del_unshare.sh real 0m4.761s user 0m0.851s sys 1m8.343s lpk43:~# Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_tunnel.c')
1 files changed, 12 insertions, 8 deletions
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 602597dfc395..5fcb17cb426b 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -347,8 +347,7 @@ static struct ip_tunnel *ip_tunnel_create(struct net *net,
struct net_device *dev;
int t_hlen;
- BUG_ON(!itn->fb_tunnel_dev);
- dev = __ip_tunnel_create(net, itn->fb_tunnel_dev->rtnl_link_ops, parms);
+ dev = __ip_tunnel_create(net, itn->rtnl_link_ops, parms);
if (IS_ERR(dev))
return ERR_CAST(dev);
@@ -822,7 +821,6 @@ int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
struct net *net = t->net;
struct ip_tunnel_net *itn = net_generic(net, t->ip_tnl_net_id);
- BUG_ON(!itn->fb_tunnel_dev);
switch (cmd) {
if (dev == itn->fb_tunnel_dev) {
@@ -847,7 +845,7 @@ int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
p->o_key = 0;
- t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
+ t = ip_tunnel_find(itn, p, itn->type);
if (cmd == SIOCADDTUNNEL) {
if (!t) {
@@ -991,10 +989,15 @@ int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
struct ip_tunnel_parm parms;
unsigned int i;
+ itn->rtnl_link_ops = ops;
for (i = 0; i < IP_TNL_HASH_SIZE; i++)
- if (!ops) {
+ if (!ops || !net_has_fallback_tunnels(net)) {
+ struct ip_tunnel_net *it_init_net;
+ it_init_net = net_generic(&init_net, ip_tnl_net_id);
+ itn->type = it_init_net->type;
itn->fb_tunnel_dev = NULL;
return 0;
@@ -1012,6 +1015,7 @@ int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
itn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
itn->fb_tunnel_dev->mtu = ip_tunnel_bind_dev(itn->fb_tunnel_dev);
ip_tunnel_add(itn, netdev_priv(itn->fb_tunnel_dev));
+ itn->type = itn->fb_tunnel_dev->type;
@@ -1019,10 +1023,10 @@ int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
-static void ip_tunnel_destroy(struct ip_tunnel_net *itn, struct list_head *head,
+static void ip_tunnel_destroy(struct net *net, struct ip_tunnel_net *itn,
+ struct list_head *head,
struct rtnl_link_ops *ops)
- struct net *net = dev_net(itn->fb_tunnel_dev);
struct net_device *dev, *aux;
int h;
@@ -1054,7 +1058,7 @@ void ip_tunnel_delete_nets(struct list_head *net_list, unsigned int id,
list_for_each_entry(net, net_list, exit_list) {
itn = net_generic(net, id);
- ip_tunnel_destroy(itn, &list, ops);
+ ip_tunnel_destroy(net, itn, &list, ops);