After the patch
'ipv6: Only create RTF_CACHE routes after encountering pmtu exception',
we need to compensate the performance hit (bouncing dst->__refcnt).
Signed-off-by: Martin KaFai Lau <ka...@fb.com>
Reviewed-by: Hannes Frederic Sowa <han...@stressinduktion.org>
Cc: Steffen Klassert <steffen.klass...@secunet.com>
---
include/net/ip6_fib.h | 8 +++
include/net/ip6_route.h | 2 +-
include/uapi/linux/ipv6_route.h | 1 +
net/ipv6/ip6_fib.c | 25 ++++++-
net/ipv6/ip6_tunnel.c | 2 +-
net/ipv6/route.c | 150 +++++++++++++++++++++++++++++++++++-----
net/ipv6/tcp_ipv6.c | 3 +-
net/ipv6/xfrm6_policy.c | 6 +-
net/netfilter/ipvs/ip_vs_xmit.c | 2 +-
net/sctp/ipv6.c | 2 +-
10 files changed, 171 insertions(+), 30 deletions(-)
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index e000180..4b1fc9b 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -121,6 +121,7 @@ struct rt6_info {
struct rt6key rt6i_prefsrc;
struct inet6_dev *rt6i_idev;
+ struct rt6_info __rcu * __percpu *rt6i_pcpu;
u32 rt6i_metric;
u32 rt6i_pmtu;
@@ -159,6 +160,13 @@ static inline void rt6_update_expires(struct rt6_info
*rt0, int timeout)
rt0->rt6i_flags |= RTF_EXPIRES;
}
+static inline u32 rt6_get_cookie(const struct rt6_info *rt)
+{
+ if (rt->rt6i_flags & RTF_PCPU)
+ rt = (struct rt6_info *)(rt->dst.from);
+ return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+}
+
static inline void ip6_rt_put(struct rt6_info *rt)
{
/* dst_release() accepts a NULL parameter.
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 0e4d170..397dd3a 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -145,7 +145,7 @@ static inline void __ip6_dst_store(struct sock *sk, struct
dst_entry *dst,
#ifdef CONFIG_IPV6_SUBTREES
np->saddr_cache = saddr;
#endif
- np->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+ np->dst_cookie = rt6_get_cookie(rt);
}
static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
diff --git a/include/uapi/linux/ipv6_route.h b/include/uapi/linux/ipv6_route.h
index 2be7bd1..f6598d1 100644
--- a/include/uapi/linux/ipv6_route.h
+++ b/include/uapi/linux/ipv6_route.h
@@ -34,6 +34,7 @@
#define RTF_PREF(pref) ((pref) << 27)
#define RTF_PREF_MASK 0x18000000
+#define RTF_PCPU 0x40000000
#define RTF_LOCAL 0x80000000
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 96dbfff..bf12be7 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -154,10 +154,33 @@ static void node_free(struct fib6_node *fn)
kmem_cache_free(fib6_node_kmem, fn);
}
+static void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
+{
+ int cpu;
+
+ if (!non_pcpu_rt->rt6i_pcpu)
+ return;
+
+ for_each_possible_cpu(cpu) {
+ struct rt6_info **ppcpu_rt;
+ struct rt6_info *pcpu_rt;
+
+ ppcpu_rt = per_cpu_ptr(non_pcpu_rt->rt6i_pcpu, cpu);
+ pcpu_rt = rcu_dereference_protected(*ppcpu_rt,
+ lockdep_is_held(&non_pcpu_rt->rt6i_table->tb6_lock));
+ if (pcpu_rt) {
+ dst_free(&pcpu_rt->dst);
+ *ppcpu_rt = NULL;
+ }
+ }
+}
+
static void rt6_release(struct rt6_info *rt)
{
- if (atomic_dec_and_test(&rt->rt6i_ref))
+ if (atomic_dec_and_test(&rt->rt6i_ref)) {
+ rt6_free_pcpu(rt);
dst_free(&rt->dst);
+ }
}
static void fib6_link_table(struct net *net, struct fib6_table *tb)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 5cafd92..2e67b66 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -151,7 +151,7 @@ EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
{
struct rt6_info *rt = (struct rt6_info *) dst;
- t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+ t->dst_cookie = rt6_get_cookie(rt);
dst_release(t->dst_cache);
t->dst_cache = dst;
}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index cb3c585..29227a0 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -108,11 +108,18 @@ static struct rt6_info *rt6_get_route_info(struct net
*net,
const struct in6_addr *gwaddr, int
ifindex);
#endif
+static u32 *rt6_pcpu_cow_metrics(struct rt6_info *rt)
+{
+ return dst_metrics_write_ptr(rt->dst.from);
+}
+
static u32 *ipv6_cow_metrics(struct dst_entry *dst, unsigned long old)
{
struct rt6_info *rt = (struct rt6_info *)dst;
- if (rt->rt6i_flags & RTF_CACHE)
+ if (rt->rt6i_flags & RTF_PCPU)
+ return rt6_pcpu_cow_metrics(rt);
+ else if (rt->rt6i_flags & RTF_CACHE)
return NULL;
else
return dst_cow_metrics_generic(dst, old);
@@ -252,10 +259,10 @@ static const struct rt6_info ip6_blk_hole_entry_template
= {
#endif
/* allocate dst with ip6_dst_ops */
-static inline struct rt6_info *ip6_dst_alloc(struct net *net,
- struct net_device *dev,
- int flags,
- struct fib6_table *table)
+static struct rt6_info *__ip6_dst_alloc(struct net *net,
+ struct net_device *dev,
+ int flags,
+ struct fib6_table *table)
{
struct rt6_info *rt = dst_alloc(&net->ipv6.ip6_dst_ops, dev,
0, DST_OBSOLETE_FORCE_CHK, flags);
@@ -269,6 +276,34 @@ static inline struct rt6_info *ip6_dst_alloc(struct net
*net,
return rt;
}
+static struct rt6_info *ip6_dst_alloc(struct net *net,
+ struct net_device *dev,
+ int flags,
+ struct fib6_table *table)
+{
+ struct rt6_info *rt = __ip6_dst_alloc(net, dev, flags, table);
+
+ if (rt) {
+ rt->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, GFP_ATOMIC);
+ if (rt->rt6i_pcpu) {
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct rt6_info **p;
+
+ p = per_cpu_ptr(rt->rt6i_pcpu, cpu);
+ /* no one shares rt */
+ *p = NULL;
+ }
+ } else {
+ dst_destroy((struct dst_entry *)rt);
+ return NULL;
+ }
+ }
+
+ return rt;
+}
+
static void ip6_dst_destroy(struct dst_entry *dst)
{
struct rt6_info *rt = (struct rt6_info *)dst;
@@ -277,6 +312,9 @@ static void ip6_dst_destroy(struct dst_entry *dst)
dst_destroy_metrics_generic(dst);
+ if (rt->rt6i_pcpu)
+ free_percpu(rt->rt6i_pcpu);
+
if (idev) {
rt->rt6i_idev = NULL;
in6_dev_put(idev);
@@ -870,11 +908,69 @@ static struct rt6_info *ip6_pmtu_rt_cache_alloc(struct
rt6_info *ort,
return rt;
}
+static struct rt6_info *ip6_rt_pcpu_alloc(struct rt6_info *rt)
+{
+ struct rt6_info *pcpu_rt;
+
+ pcpu_rt = __ip6_dst_alloc(dev_net(rt->dst.dev),
+ rt->dst.dev, rt->dst.flags,
+ rt->rt6i_table);
+
+ if (!pcpu_rt)
+ return NULL;
+ ip6_rt_copy_init(pcpu_rt, rt, NULL);
+ pcpu_rt->rt6i_protocol = rt->rt6i_protocol;
+ pcpu_rt->rt6i_flags |= RTF_PCPU;
+ return pcpu_rt;
+}
+
+static struct rt6_info *rt6_get_pcpu_route(struct rt6_info *rt)
+{
+ struct rt6_info *pcpu_rt, *orig, *prev, **p;
+ struct net *net = dev_net(rt->dst.dev);
+
+ if (rt == net->ipv6.ip6_null_entry || rt->rt6i_flags & RTF_CACHE)
+ goto done;
+
+ rcu_read_lock();
+ p = raw_cpu_ptr(rt->rt6i_pcpu);
+ orig = rcu_dereference_check(*p,
+
lockdep_is_held(&rt->rt6i_table->tb6_lock));
+ if (orig) {
+ rt6_dst_from_metrics_check(orig);
+ dst_hold(&orig->dst);
+ rcu_read_unlock();
+ return orig;
+ }
+ rcu_read_unlock();
+
+ pcpu_rt = ip6_rt_pcpu_alloc(rt);
+ if (!pcpu_rt) {
+ rt = net->ipv6.ip6_null_entry;
+ goto done;
+ }
+ dst_hold(&pcpu_rt->dst);
+
+ prev = cmpxchg(p, orig, pcpu_rt);
+ if (prev == orig) {
+ if (orig)
+ call_rcu(&orig->dst.rcu_head, dst_rcu_free);
+ } else {
+ pcpu_rt->dst.flags |= DST_NOCACHE;
+ }
+ return pcpu_rt;
+
+done:
+ rt6_dst_from_metrics_check(rt);
+ dst_hold(&rt->dst);
+ return rt;
+}
+
static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table
*table, int oif,
struct flowi6 *fl6, int flags)
{
struct fib6_node *fn, *saved_fn;
- struct rt6_info *rt;
+ struct rt6_info *rt, *pcpu_rt;
int strict = 0;
strict |= flags & RT6_LOOKUP_F_IFACE;
@@ -902,14 +998,13 @@ redo_rt6_select:
}
}
- dst_hold(&rt->dst);
+ pcpu_rt = rt6_get_pcpu_route(rt);
read_unlock_bh(&table->tb6_lock);
- rt6_dst_from_metrics_check(rt);
rt->dst.lastuse = jiffies;
rt->dst.__use++;
- return rt;
+ return pcpu_rt;
}
static struct rt6_info *ip6_pol_route_input(struct net *net, struct fib6_table
*table,
@@ -1020,6 +1115,26 @@ static void rt6_dst_from_metrics_check(struct rt6_info
*rt)
dst_init_metrics(&rt->dst, dst_metrics_ptr(rt->dst.from), true);
}
+static struct dst_entry *rt6_check(struct rt6_info *rt, u32 cookie)
+{
+ if (!rt->rt6i_node || rt->rt6i_node->fn_sernum != cookie)
+ return NULL;
+
+ if (rt6_check_expired(rt))
+ return NULL;
+
+ return &rt->dst;
+}
+
+static struct dst_entry *rt6_pcpu_check(struct rt6_info *rt, u32 cookie)
+{
+ if (rt->dst.obsolete == DST_OBSOLETE_FORCE_CHK &&
+ rt6_check((struct rt6_info *)(rt->dst.from), cookie))
+ return &rt->dst;
+ else
+ return NULL;
+}
+
static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
{
struct rt6_info *rt;
@@ -1030,15 +1145,12 @@ static struct dst_entry *ip6_dst_check(struct dst_entry
*dst, u32 cookie)
* DST_OBSOLETE_FORCE_CHK which forces validation calls down
* into this function always.
*/
- if (!rt->rt6i_node || (rt->rt6i_node->fn_sernum != cookie))
- return NULL;
-
- if (rt6_check_expired(rt))
- return NULL;
-
rt6_dst_from_metrics_check(rt);
- return dst;
+ if (rt->rt6i_flags & RTF_PCPU)
+ return rt6_pcpu_check(rt, cookie);
+ else
+ return rt6_check(rt, cookie);
}
static struct dst_entry *ip6_negative_advice(struct dst_entry *dst)
@@ -1943,11 +2055,11 @@ static struct rt6_info *ip6_rt_cache_alloc(struct
rt6_info *ort,
{
struct rt6_info *rt;
- if (ort->rt6i_flags & RTF_CACHE)
+ if (ort->rt6i_flags & (RTF_PCPU | RTF_CACHE))
ort = (struct rt6_info *)ort->dst.from;
- rt = ip6_dst_alloc(dev_net(ort->dst.dev), ort->dst.dev,
- 0, ort->rt6i_table);
+ rt = __ip6_dst_alloc(dev_net(ort->dst.dev), ort->dst.dev,
+ 0, ort->rt6i_table);
if (!rt)
return NULL;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 042a645..b416305 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -99,8 +99,7 @@ static void inet6_sk_rx_dst_set(struct sock *sk, const struct
sk_buff *skb)
dst_hold(dst);
sk->sk_rx_dst = dst;
inet_sk(sk)->rx_dst_ifindex = skb->skb_iif;
- if (rt->rt6i_node)
- inet6_sk(sk)->rx_dst_cookie = rt->rt6i_node->fn_sernum;
+ inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
}
}
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 6ae256b..ed0583c 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -76,8 +76,7 @@ static int xfrm6_init_path(struct xfrm_dst *path, struct
dst_entry *dst,
{
if (dst->ops->family == AF_INET6) {
struct rt6_info *rt = (struct rt6_info *)dst;
- if (rt->rt6i_node)
- path->path_cookie = rt->rt6i_node->fn_sernum;
+ path->path_cookie = rt6_get_cookie(rt);
}
path->u.rt6.rt6i_nfheader_len = nfheader_len;
@@ -105,8 +104,7 @@ static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct
net_device *dev,
RTF_LOCAL);
xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
xdst->u.rt6.rt6i_node = rt->rt6i_node;
- if (rt->rt6i_node)
- xdst->route_cookie = rt->rt6i_node->fn_sernum;
+ xdst->route_cookie = rt6_get_cookie(rt);
xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
xdst->u.rt6.rt6i_src = rt->rt6i_src;
diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 38f8627..5eff9f6 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -435,7 +435,7 @@ __ip_vs_get_out_rt_v6(int skb_af, struct sk_buff *skb,
struct ip_vs_dest *dest,
goto err_unreach;
}
rt = (struct rt6_info *) dst;
- cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+ cookie = rt6_get_cookie(rt);
__ip_vs_dst_set(dest, dest_dst, &rt->dst, cookie);
spin_unlock_bh(&dest->dst_lock);
IP_VS_DBG(10, "new dst %pI6, src %pI6, refcnt=%d\n",
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 9fa13f6..d012834 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -331,7 +331,7 @@ out:
rt = (struct rt6_info *)dst;
t->dst = dst;
- t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
+ t->dst_cookie = rt6_get_cookie(rt);
pr_debug("rt6_dst:%pI6/%d rt6_src:%pI6\n",
&rt->rt6i_dst.addr, rt->rt6i_dst.plen,
&fl6->saddr);
--
1.8.1
--
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