fib: RCU conversion of fib_lookup()
fib_lookup() converted to be called in RCU protected context, no
reference taken and released on a contended cache line (fib_clntref)
fib_table_lookup() and fib_semantic_match() get an additional parameter.
struct fib_info gets an rcu_head field, and is freed after an rcu grace
period.
Stress test :
(Sending 160.000.000 UDP frames on same neighbour,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_HASH) (about same results for FIB_TRIE)
Before patch :
real 1m31.199s
user 0m13.761s
sys 23m24.780s
After patch:
real 1m5.375s
user 0m14.997s
sys 15m50.115s
Before patch Profile :
13044.00 15.4% __ip_route_output_key vmlinux
8438.00 10.0% dst_destroy vmlinux
5983.00 7.1% fib_semantic_match vmlinux
5410.00 6.4% fib_rules_lookup vmlinux
4803.00 5.7% neigh_lookup vmlinux
4420.00 5.2% _raw_spin_lock vmlinux
3883.00 4.6% rt_set_nexthop vmlinux
3261.00 3.9% _raw_read_lock vmlinux
2794.00 3.3% fib_table_lookup vmlinux
2374.00 2.8% neigh_resolve_output vmlinux
2153.00 2.5% dst_alloc vmlinux
1502.00 1.8% _raw_read_lock_bh vmlinux
1484.00 1.8% kmem_cache_alloc vmlinux
1407.00 1.7% eth_header vmlinux
1406.00 1.7% ipv4_dst_destroy vmlinux
1298.00 1.5% __copy_from_user_ll vmlinux
1174.00 1.4% dev_queue_xmit vmlinux
1000.00 1.2% ip_output vmlinux
After patch Profile :
13712.00 15.8% dst_destroy vmlinux
8548.00 9.9% __ip_route_output_key vmlinux
7017.00 8.1% neigh_lookup vmlinux
4554.00 5.3% fib_semantic_match vmlinux
4067.00 4.7% _raw_read_lock vmlinux
3491.00 4.0% dst_alloc vmlinux
3186.00 3.7% neigh_resolve_output vmlinux
3103.00 3.6% fib_table_lookup vmlinux
2098.00 2.4% _raw_read_lock_bh vmlinux
2081.00 2.4% kmem_cache_alloc vmlinux
2013.00 2.3% _raw_spin_lock vmlinux
1763.00 2.0% __copy_from_user_ll vmlinux
1763.00 2.0% ip_output vmlinux
1761.00 2.0% ipv4_dst_destroy vmlinux
1631.00 1.9% eth_header vmlinux
1440.00 1.7% _raw_read_unlock_bh vmlinux
Reference results, if IP route cache is enabled :
real 0m29.718s
user 0m10.845s
sys 7m37.341s
25213.00 29.5% __ip_route_output_key vmlinux
9011.00 10.5% dst_release vmlinux
4817.00 5.6% ip_push_pending_frames vmlinux
4232.00 5.0% ip_finish_output vmlinux
3940.00 4.6% udp_sendmsg vmlinux
3730.00 4.4% __copy_from_user_ll vmlinux
3716.00 4.4% ip_route_output_flow vmlinux
2451.00 2.9% __xfrm_lookup vmlinux
2221.00 2.6% ip_append_data vmlinux
1718.00 2.0% _raw_spin_lock_bh vmlinux
1655.00 1.9% __alloc_skb vmlinux
1572.00 1.8% sock_wfree vmlinux
1345.00 1.6% kfree vmlinux
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index cfb7d25..21698f8 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -225,7 +225,8 @@
err = ops->action(rule, fl, flags, arg);
if (err != -EAGAIN) {
- if (likely(atomic_inc_not_zero(&rule->refcnt))) {
+ if ((arg->flags & FIB_LOOKUP_NOREF) ||
+ likely(atomic_inc_not_zero(&rule->refcnt))) {
arg->rule = rule;
goto out;
}
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index b05c23b..919f2ad 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -168,8 +168,11 @@
struct fib_result res = { 0 };
struct net_device *dev = NULL;
- if (fib_lookup(net, &fl, &res))
+ rcu_read_lock();
+ if (fib_lookup(net, &fl, &res)) {
+ rcu_read_unlock();
return NULL;
+ }
if (res.type != RTN_LOCAL)
goto out;
dev = FIB_RES_DEV(res);
@@ -177,7 +180,7 @@
if (dev && devref)
dev_hold(dev);
out:
- fib_res_put(&res);
+ rcu_read_unlock();
return dev;
}
EXPORT_SYMBOL(__ip_dev_find);
@@ -207,11 +210,12 @@
local_table = fib_get_table(net, RT_TABLE_LOCAL);
if (local_table) {
ret = RTN_UNICAST;
- if (!fib_table_lookup(local_table, &fl, &res)) {
+ rcu_read_lock();
+ if (!fib_table_lookup(local_table, &fl, &res, FIB_LOOKUP_NOREF)) {
if (!dev || dev == res.fi->fib_dev)
ret = res.type;
- fib_res_put(&res);
}
+ rcu_read_unlock();
}
return ret;
}
@@ -235,6 +239,7 @@
* - figure out what "logical" interface this packet arrived
* and calculate "specific destination" address.
* - check, that packet arrived from expected physical interface.
+ * called with rcu_read_lock()
*/
int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
struct net_device *dev, __be32 *spec_dst,
@@ -259,7 +264,6 @@
struct net *net;
no_addr = rpf = accept_local = 0;
- rcu_read_lock();
in_dev = __in_dev_get_rcu(dev);
if (in_dev) {
no_addr = in_dev->ifa_list == NULL;
@@ -268,7 +272,6 @@
if (mark && !IN_DEV_SRC_VMARK(in_dev))
fl.mark = 0;
}
- rcu_read_unlock();
if (in_dev == NULL)
goto e_inval;
@@ -278,7 +281,7 @@
goto last_resort;
if (res.type != RTN_UNICAST) {
if (res.type != RTN_LOCAL || !accept_local)
- goto e_inval_res;
+ goto e_inval;
}
*spec_dst = FIB_RES_PREFSRC(res);
fib_combine_itag(itag, &res);
@@ -299,10 +302,8 @@
#endif
if (dev_match) {
ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
- fib_res_put(&res);
return ret;
}
- fib_res_put(&res);
if (no_addr)
goto last_resort;
if (rpf == 1)
@@ -315,7 +316,6 @@
*spec_dst = FIB_RES_PREFSRC(res);
ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
}
- fib_res_put(&res);
}
return ret;
@@ -326,8 +326,6 @@
*itag = 0;
return 0;
-e_inval_res:
- fib_res_put(&res);
e_inval:
return -EINVAL;
e_rpf:
@@ -873,15 +871,16 @@
local_bh_disable();
frn->tb_id = tb->tb_id;
- frn->err = fib_table_lookup(tb, &fl, &res);
+ rcu_read_lock();
+ frn->err = fib_table_lookup(tb, &fl, &res, FIB_LOOKUP_NOREF);
if (!frn->err) {
frn->prefixlen = res.prefixlen;
frn->nh_sel = res.nh_sel;
frn->type = res.type;
frn->scope = res.scope;
- fib_res_put(&res);
}
+ rcu_read_unlock();
local_bh_enable();
}
}
diff --git a/net/ipv4/fib_hash.c b/net/ipv4/fib_hash.c
index 4ed7e0d..83cca68 100644
--- a/net/ipv4/fib_hash.c
+++ b/net/ipv4/fib_hash.c
@@ -244,7 +244,8 @@
}
int fib_table_lookup(struct fib_table *tb,
- const struct flowi *flp, struct fib_result *res)
+ const struct flowi *flp, struct fib_result *res,
+ int fib_flags)
{
int err;
struct fn_zone *fz;
@@ -264,7 +265,7 @@
err = fib_semantic_match(&f->fn_alias,
flp, res,
- fz->fz_order);
+ fz->fz_order, fib_flags);
if (err <= 0)
goto out;
}
diff --git a/net/ipv4/fib_lookup.h b/net/ipv4/fib_lookup.h
index 637b133..b9c9a9f 100644
--- a/net/ipv4/fib_lookup.h
+++ b/net/ipv4/fib_lookup.h
@@ -22,7 +22,7 @@
/* Exported by fib_semantics.c */
extern int fib_semantic_match(struct list_head *head,
const struct flowi *flp,
- struct fib_result *res, int prefixlen);
+ struct fib_result *res, int prefixlen, int fib_flags);
extern void fib_release_info(struct fib_info *);
extern struct fib_info *fib_create_info(struct fib_config *cfg);
extern int fib_nh_match(struct fib_config *cfg, struct fib_info *fi);
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index 3230052..7981a24 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -57,6 +57,7 @@
{
struct fib_lookup_arg arg = {
.result = res,
+ .flags = FIB_LOOKUP_NOREF,
};
int err;
@@ -94,7 +95,7 @@
if (!tbl)
goto errout;
- err = fib_table_lookup(tbl, flp, (struct fib_result *) arg->result);
+ err = fib_table_lookup(tbl, flp, (struct fib_result *) arg->result, arg->flags);
if (err > 0)
err = -EAGAIN;
errout:
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index ba52f39..0f80dfc 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -148,6 +148,13 @@
/* Release a nexthop info record */
+static void free_fib_info_rcu(struct rcu_head *head)
+{
+ struct fib_info *fi = container_of(head, struct fib_info, rcu);
+
+ kfree(fi);
+}
+
void free_fib_info(struct fib_info *fi)
{
if (fi->fib_dead == 0) {
@@ -161,7 +168,7 @@
} endfor_nexthops(fi);
fib_info_cnt--;
release_net(fi->fib_net);
- kfree(fi);
+ call_rcu(&fi->rcu, free_fib_info_rcu);
}
void fib_release_info(struct fib_info *fi)
@@ -553,6 +560,7 @@
nh->nh_scope = RT_SCOPE_LINK;
return 0;
}
+ rcu_read_lock();
{
struct flowi fl = {
.nl_u = {
@@ -568,8 +576,10 @@
if (fl.fl4_scope < RT_SCOPE_LINK)
fl.fl4_scope = RT_SCOPE_LINK;
err = fib_lookup(net, &fl, &res);
- if (err)
+ if (err) {
+ rcu_read_unlock();
return err;
+ }
}
err = -EINVAL;
if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
@@ -585,7 +595,7 @@
goto out;
err = 0;
out:
- fib_res_put(&res);
+ rcu_read_unlock();
return err;
} else {
struct in_device *in_dev;
@@ -879,7 +889,7 @@
/* Note! fib_semantic_match intentionally uses RCU list functions. */
int fib_semantic_match(struct list_head *head, const struct flowi *flp,
- struct fib_result *res, int prefixlen)
+ struct fib_result *res, int prefixlen, int fib_flags)
{
struct fib_alias *fa;
int nh_sel = 0;
@@ -943,7 +953,8 @@
res->type = fa->fa_type;
res->scope = fa->fa_scope;
res->fi = fa->fa_info;
- atomic_inc(&res->fi->fib_clntref);
+ if (!(fib_flags & FIB_LOOKUP_NOREF))
+ atomic_inc(&res->fi->fib_clntref);
return 0;
}
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index a96e5ec..271c89b 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1342,7 +1342,7 @@
/* should be called with rcu_read_lock */
static int check_leaf(struct trie *t, struct leaf *l,
t_key key, const struct flowi *flp,
- struct fib_result *res)
+ struct fib_result *res, int fib_flags)
{
struct leaf_info *li;
struct hlist_head *hhead = &l->list;
@@ -1356,7 +1356,7 @@
if (l->key != (key & ntohl(mask)))
continue;
- err = fib_semantic_match(&li->falh, flp, res, plen);
+ err = fib_semantic_match(&li->falh, flp, res, plen, fib_flags);
#ifdef CONFIG_IP_FIB_TRIE_STATS
if (err <= 0)
@@ -1372,7 +1372,7 @@
}
int fib_table_lookup(struct fib_table *tb, const struct flowi *flp,
- struct fib_result *res)
+ struct fib_result *res, int fib_flags)
{
struct trie *t = (struct trie *) tb->tb_data;
int ret;
@@ -1399,7 +1399,7 @@
/* Just a leaf? */
if (IS_LEAF(n)) {
- ret = check_leaf(t, (struct leaf *)n, key, flp, res);
+ ret = check_leaf(t, (struct leaf *)n, key, flp, res, fib_flags);
goto found;
}
@@ -1424,7 +1424,7 @@
}
if (IS_LEAF(n)) {
- ret = check_leaf(t, (struct leaf *)n, key, flp, res);
+ ret = check_leaf(t, (struct leaf *)n, key, flp, res, fib_flags);
if (ret > 0)
goto backtrace;
goto found;
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 04e0df8..7864d0c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1773,12 +1773,15 @@
if (rt->fl.iif == 0)
src = rt->rt_src;
- else if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0) {
- src = FIB_RES_PREFSRC(res);
- fib_res_put(&res);
- } else
- src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
+ else {
+ rcu_read_lock();
+ if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0)
+ src = FIB_RES_PREFSRC(res);
+ else
+ src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
RT_SCOPE_UNIVERSE);
+ rcu_read_unlock();
+ }
memcpy(addr, &src, 4);
}
@@ -2081,6 +2084,7 @@
* Such approach solves two big problems:
* 1. Not simplex devices are handled properly.
* 2. IP spoofing attempts are filtered with 100% of guarantee.
+ * called with rcu_read_lock()
*/
static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2102,7 +2106,6 @@
unsigned hash;
__be32 spec_dst;
int err = -EINVAL;
- int free_res = 0;
struct net * net = dev_net(dev);
/* IP on this device is disabled. */
@@ -2134,12 +2137,12 @@
/*
* Now we are ready to route packet.
*/
- if ((err = fib_lookup(net, &fl, &res)) != 0) {
+ err = fib_lookup(net, &fl, &res);
+ if (err != 0) {
if (!IN_DEV_FORWARD(in_dev))
goto e_hostunreach;
goto no_route;
}
- free_res = 1;
RT_CACHE_STAT_INC(in_slow_tot);
@@ -2148,8 +2151,8 @@
if (res.type == RTN_LOCAL) {
err = fib_validate_source(saddr, daddr, tos,
- net->loopback_dev->ifindex,
- dev, &spec_dst, &itag, skb->mark);
+ net->loopback_dev->ifindex,
+ dev, &spec_dst, &itag, skb->mark);
if (err < 0)
goto martian_source_keep_err;
if (err)
@@ -2164,9 +2167,6 @@
goto martian_destination;
err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
-done:
- if (free_res)
- fib_res_put(&res);
out: return err;
brd_input:
@@ -2226,7 +2226,7 @@
rth->rt_type = res.type;
hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net));
err = rt_intern_hash(hash, rth, NULL, skb, fl.iif);
- goto done;
+ goto out;
no_route:
RT_CACHE_STAT_INC(in_no_route);
@@ -2249,21 +2249,21 @@
e_hostunreach:
err = -EHOSTUNREACH;
- goto done;
+ goto out;
e_inval:
err = -EINVAL;
- goto done;
+ goto out;
e_nobufs:
err = -ENOBUFS;
- goto done;
+ goto out;
martian_source:
err = -EINVAL;
martian_source_keep_err:
ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
- goto done;
+ goto out;
}
int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2349,6 +2349,7 @@
}
EXPORT_SYMBOL(ip_route_input_common);
+/* called with rcu_read_lock() */
static int __mkroute_output(struct rtable **result,
struct fib_result *res,
const struct flowi *fl,
@@ -2373,18 +2374,13 @@
if (dev_out->flags & IFF_LOOPBACK)
flags |= RTCF_LOCAL;
- rcu_read_lock();
in_dev = __in_dev_get_rcu(dev_out);
- if (!in_dev) {
- rcu_read_unlock();
+ if (!in_dev)
return -EINVAL;
- }
+
if (res->type == RTN_BROADCAST) {
flags |= RTCF_BROADCAST | RTCF_LOCAL;
- if (res->fi) {
- fib_info_put(res->fi);
- res->fi = NULL;
- }
+ res->fi = NULL;
} else if (res->type == RTN_MULTICAST) {
flags |= RTCF_MULTICAST | RTCF_LOCAL;
if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
@@ -2394,10 +2390,8 @@
* default one, but do not gateway in this case.
* Yes, it is hack.
*/
- if (res->fi && res->prefixlen < 4) {
- fib_info_put(res->fi);
+ if (res->fi && res->prefixlen < 4)
res->fi = NULL;
- }
}
@@ -2467,6 +2461,7 @@
return 0;
}
+/* called with rcu_read_lock() */
static int ip_mkroute_output(struct rtable **rp,
struct fib_result *res,
const struct flowi *fl,
@@ -2509,7 +2504,6 @@
struct fib_result res;
unsigned int flags = 0;
struct net_device *dev_out = NULL;
- int free_res = 0;
int err;
@@ -2636,15 +2630,12 @@
err = -ENETUNREACH;
goto out;
}
- free_res = 1;
if (res.type == RTN_LOCAL) {
if (!fl.fl4_src)
fl.fl4_src = fl.fl4_dst;
dev_out = net->loopback_dev;
fl.oif = dev_out->ifindex;
- if (res.fi)
- fib_info_put(res.fi);
res.fi = NULL;
flags |= RTCF_LOCAL;
goto make_route;
@@ -2668,8 +2659,6 @@
make_route:
err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
- if (free_res)
- fib_res_put(&res);
out: return err;
}