ipv6: addrlabel: per netns list

Having a global list of labels do not scale to thousands of
netns in the cloud era. This causes quadratic behavior on
netns creation and deletion.

This is time having a per netns list of ~10 labels.

Tested:

$ time perf record (for f in `seq 1 3000` ; do ip netns add tast$f; done)
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 3.637 MB perf.data (~158898 samples) ]

real    0m20.837s # instead of 0m24.227s
user    0m0.328s
sys     0m20.338s # instead of 0m23.753s

    16.17%       ip  [kernel.kallsyms]  [k] netlink_broadcast_filtered
    12.30%       ip  [kernel.kallsyms]  [k] netlink_has_listeners
     6.76%       ip  [kernel.kallsyms]  [k] _raw_spin_lock_irqsave
     5.78%       ip  [kernel.kallsyms]  [k] memset_erms
     5.77%       ip  [kernel.kallsyms]  [k] kobject_uevent_env
     5.18%       ip  [kernel.kallsyms]  [k] refcount_sub_and_test
     4.96%       ip  [kernel.kallsyms]  [k] _raw_read_lock
     3.82%       ip  [kernel.kallsyms]  [k] refcount_inc_not_zero
     3.33%       ip  [kernel.kallsyms]  [k] _raw_spin_unlock_irqrestore
     2.11%       ip  [kernel.kallsyms]  [k] unmap_page_range
     1.77%       ip  [kernel.kallsyms]  [k] __wake_up
     1.69%       ip  [kernel.kallsyms]  [k] strlen
     1.17%       ip  [kernel.kallsyms]  [k] __wake_up_common
     1.09%       ip  [kernel.kallsyms]  [k] insert_header
     1.04%       ip  [kernel.kallsyms]  [k] page_remove_rmap
     1.01%       ip  [kernel.kallsyms]  [k] consume_skb
     0.98%       ip  [kernel.kallsyms]  [k] netlink_trim
     0.51%       ip  [kernel.kallsyms]  [k] kernfs_link_sibling
     0.51%       ip  [kernel.kallsyms]  [k] filemap_map_pages
     0.46%       ip  [kernel.kallsyms]  [k] memcpy_erms

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 30 insertions, 51 deletions

diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index b055bc79f56d..c6311d7108f6 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -30,7 +30,6 @@
  * Policy Table
  */
 struct ip6addrlbl_entry {
-        possible_net_t lbl_net;
         struct in6_addr prefix;
         int prefixlen;
         int ifindex;
@@ -41,19 +40,6 @@ struct ip6addrlbl_entry {
         struct rcu_head rcu;
 };
 
-static struct ip6addrlbl_table
-{
-        struct hlist_head head;
-        spinlock_t lock;
-        u32 seq;
-} ip6addrlbl_table;
-
-static inline
-struct net *ip6addrlbl_net(const struct ip6addrlbl_entry *lbl)
-{
-        return read_pnet(&lbl->lbl_net);
-}
-
 /*
  * Default policy table (RFC6724 + extensions)
  *
@@ -148,13 +134,10 @@ static inline void ip6addrlbl_put(struct ip6addrlbl_entry *p)
 }
 
 /* Find label */
-static bool __ip6addrlbl_match(struct net *net,
-                               const struct ip6addrlbl_entry *p,
+static bool __ip6addrlbl_match(const struct ip6addrlbl_entry *p,
                                const struct in6_addr *addr,
                                int addrtype, int ifindex)
 {
-        if (!net_eq(ip6addrlbl_net(p), net))
-                return false;
         if (p->ifindex && p->ifindex != ifindex)
                 return false;
         if (p->addrtype && p->addrtype != addrtype)
@@ -169,8 +152,9 @@ static struct ip6addrlbl_entry *__ipv6_addr_label(struct net *net,
                                                   int type, int ifindex)
 {
         struct ip6addrlbl_entry *p;
-        hlist_for_each_entry_rcu(p, &ip6addrlbl_table.head, list) {
-                if (__ip6addrlbl_match(net, p, addr, type, ifindex))
+
+        hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
+                if (__ip6addrlbl_match(p, addr, type, ifindex))
                         return p;
         }
         return NULL;
@@ -196,8 +180,7 @@ u32 ipv6_addr_label(struct net *net,
 }
 
 /* allocate one entry */
-static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
-                                                 const struct in6_addr *prefix,
+static struct ip6addrlbl_entry *ip6addrlbl_alloc(const struct in6_addr *prefix,
                                                  int prefixlen, int ifindex,
                                                  u32 label)
 {
@@ -236,24 +219,23 @@ static struct ip6addrlbl_entry *ip6addrlbl_alloc(struct net *net,
         newp->addrtype = addrtype;
         newp->label = label;
         INIT_HLIST_NODE(&newp->list);
-        write_pnet(&newp->lbl_net, net);
         refcount_set(&newp->refcnt, 1);
         return newp;
 }
 
 /* add a label */
-static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
+static int __ip6addrlbl_add(struct net *net, struct ip6addrlbl_entry *newp,
+                            int replace)
 {
-        struct hlist_node *n;
         struct ip6addrlbl_entry *last = NULL, *p = NULL;
+        struct hlist_node *n;
         int ret = 0;
 
         ADDRLABEL(KERN_DEBUG "%s(newp=%p, replace=%d)\n", __func__, newp,
                   replace);
 
-        hlist_for_each_entry_safe(p, n, &ip6addrlbl_table.head, list) {
+        hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
                 if (p->prefixlen == newp->prefixlen &&
-                    net_eq(ip6addrlbl_net(p), ip6addrlbl_net(newp)) &&
                     p->ifindex == newp->ifindex &&
                     ipv6_addr_equal(&p->prefix, &newp->prefix)) {
                         if (!replace) {
@@ -273,10 +255,10 @@ static int __ip6addrlbl_add(struct ip6addrlbl_entry *newp, int replace)
         if (last)
                 hlist_add_behind_rcu(&newp->list, &last->list);
         else
-                hlist_add_head_rcu(&newp->list, &ip6addrlbl_table.head);
+                hlist_add_head_rcu(&newp->list, &net->ipv6.ip6addrlbl_table.head);
 out:
         if (!ret)
-                ip6addrlbl_table.seq++;
+                net->ipv6.ip6addrlbl_table.seq++;
         return ret;
 }
 
@@ -292,12 +274,12 @@ static int ip6addrlbl_add(struct net *net,
                   __func__, prefix, prefixlen, ifindex, (unsigned int)label,
                   replace);
 
-        newp = ip6addrlbl_alloc(net, prefix, prefixlen, ifindex, label);
+        newp = ip6addrlbl_alloc(prefix, prefixlen, ifindex, label);
         if (IS_ERR(newp))
                 return PTR_ERR(newp);
-        spin_lock(&ip6addrlbl_table.lock);
-        ret = __ip6addrlbl_add(newp, replace);
-        spin_unlock(&ip6addrlbl_table.lock);
+        spin_lock(&net->ipv6.ip6addrlbl_table.lock);
+        ret = __ip6addrlbl_add(net, newp, replace);
+        spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
         if (ret)
                 ip6addrlbl_free(newp);
         return ret;
@@ -315,9 +297,8 @@ static int __ip6addrlbl_del(struct net *net,
         ADDRLABEL(KERN_DEBUG "%s(prefix=%pI6, prefixlen=%d, ifindex=%d)\n",
                   __func__, prefix, prefixlen, ifindex);
 
-        hlist_for_each_entry_safe(p, n, &ip6addrlbl_table.head, list) {
+        hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
                 if (p->prefixlen == prefixlen &&
-                    net_eq(ip6addrlbl_net(p), net) &&
                     p->ifindex == ifindex &&
                     ipv6_addr_equal(&p->prefix, prefix)) {
                         hlist_del_rcu(&p->list);
@@ -340,9 +321,9 @@ static int ip6addrlbl_del(struct net *net,
                   __func__, prefix, prefixlen, ifindex);
 
         ipv6_addr_prefix(&prefix_buf, prefix, prefixlen);
-        spin_lock(&ip6addrlbl_table.lock);
+        spin_lock(&net->ipv6.ip6addrlbl_table.lock);
         ret = __ip6addrlbl_del(net, &prefix_buf, prefixlen, ifindex);
-        spin_unlock(&ip6addrlbl_table.lock);
+        spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
         return ret;
 }
 
@@ -354,6 +335,9 @@ static int __net_init ip6addrlbl_net_init(struct net *net)
 
         ADDRLABEL(KERN_DEBUG "%s\n", __func__);
 
+        spin_lock_init(&net->ipv6.ip6addrlbl_table.lock);
+        INIT_HLIST_HEAD(&net->ipv6.ip6addrlbl_table.head);
+
         for (i = 0; i < ARRAY_SIZE(ip6addrlbl_init_table); i++) {
                 int ret = ip6addrlbl_add(net,
                                          ip6addrlbl_init_table[i].prefix,
@@ -373,14 +357,12 @@ static void __net_exit ip6addrlbl_net_exit(struct net *net)
         struct hlist_node *n;
 
         /* Remove all labels belonging to the exiting net */
-        spin_lock(&ip6addrlbl_table.lock);
-        hlist_for_each_entry_safe(p, n, &ip6addrlbl_table.head, list) {
-                if (net_eq(ip6addrlbl_net(p), net)) {
-                        hlist_del_rcu(&p->list);
-                        ip6addrlbl_put(p);
-                }
+        spin_lock(&net->ipv6.ip6addrlbl_table.lock);
+        hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
+                hlist_del_rcu(&p->list);
+                ip6addrlbl_put(p);
         }
-        spin_unlock(&ip6addrlbl_table.lock);
+        spin_unlock(&net->ipv6.ip6addrlbl_table.lock);
 }
 
 static struct pernet_operations ipv6_addr_label_ops = {
@@ -390,8 +372,6 @@ static struct pernet_operations ipv6_addr_label_ops = {
 
 int __init ipv6_addr_label_init(void)
 {
-        spin_lock_init(&ip6addrlbl_table.lock);
-
         return register_pernet_subsys(&ipv6_addr_label_ops);
 }
 
@@ -510,11 +490,10 @@ static int ip6addrlbl_dump(struct sk_buff *skb, struct netlink_callback *cb)
         int err;
 
         rcu_read_lock();
-        hlist_for_each_entry_rcu(p, &ip6addrlbl_table.head, list) {
-                if (idx >= s_idx &&
-                    net_eq(ip6addrlbl_net(p), net)) {
+        hlist_for_each_entry_rcu(p, &net->ipv6.ip6addrlbl_table.head, list) {
+                if (idx >= s_idx) {
                         err = ip6addrlbl_fill(skb, p,
-                                              ip6addrlbl_table.seq,
+                                              net->ipv6.ip6addrlbl_table.seq,
                                               NETLINK_CB(cb->skb).portid,
                                               cb->nlh->nlmsg_seq,
                                               RTM_NEWADDRLABEL,
@@ -571,7 +550,7 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
         p = __ipv6_addr_label(net, addr, ipv6_addr_type(addr), ifal->ifal_index);
         if (p && !ip6addrlbl_hold(p))
                 p = NULL;
-        lseq = ip6addrlbl_table.seq;
+        lseq = net->ipv6.ip6addrlbl_table.seq;
         rcu_read_unlock();
 
         if (!p) {