Commit ebc0ffae authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c2952c31
......@@ -31,6 +31,8 @@ struct fib_lookup_arg {
void *lookup_ptr;
void *result;
struct fib_rule *rule;
int flags;
#define FIB_LOOKUP_NOREF 1
};
struct fib_rules_ops {
......
......@@ -86,6 +86,7 @@ struct fib_info {
#ifdef CONFIG_IP_ROUTE_MULTIPATH
int fib_power;
#endif
struct rcu_head rcu;
struct fib_nh fib_nh[0];
#define fib_dev fib_nh[0].nh_dev
};
......@@ -148,7 +149,7 @@ struct fib_table {
};
extern int fib_table_lookup(struct fib_table *tb, const struct flowi *flp,
struct fib_result *res);
struct fib_result *res, int fib_flags);
extern int fib_table_insert(struct fib_table *, struct fib_config *);
extern int fib_table_delete(struct fib_table *, struct fib_config *);
extern int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
......@@ -185,11 +186,11 @@ static inline int fib_lookup(struct net *net, const struct flowi *flp,
struct fib_table *table;
table = fib_get_table(net, RT_TABLE_LOCAL);
if (!fib_table_lookup(table, flp, res))
if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
return 0;
table = fib_get_table(net, RT_TABLE_MAIN);
if (!fib_table_lookup(table, flp, res))
if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
return 0;
return -ENETUNREACH;
}
......@@ -254,16 +255,6 @@ static inline void fib_info_put(struct fib_info *fi)
free_fib_info(fi);
}
static inline void fib_res_put(struct fib_result *res)
{
if (res->fi)
fib_info_put(res->fi);
#ifdef CONFIG_IP_MULTIPLE_TABLES
if (res->r)
fib_rule_put(res->r);
#endif
}
#ifdef CONFIG_PROC_FS
extern int __net_init fib_proc_init(struct net *net);
extern void __net_exit fib_proc_exit(struct net *net);
......
......@@ -225,7 +225,8 @@ int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl,
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;
}
......
......@@ -168,8 +168,11 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
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 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
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 @@ static inline unsigned __inet_dev_addr_type(struct net *net,
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 @@ EXPORT_SYMBOL(inet_dev_addr_type);
* - 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 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
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 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
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 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
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 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
#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 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
*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 @@ int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
*itag = 0;
return 0;
e_inval_res:
fib_res_put(&res);
e_inval:
return -EINVAL;
e_rpf:
......@@ -873,15 +871,16 @@ static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
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();
}
}
......
......@@ -244,7 +244,8 @@ fn_new_zone(struct fn_hash *table, int z)
}
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 @@ int fib_table_lookup(struct fib_table *tb,
err = fib_semantic_match(&f->fn_alias,
flp, res,
fz->fz_order);
fz->fz_order, fib_flags);
if (err <= 0)
goto out;
}
......
......@@ -22,7 +22,7 @@ struct fib_alias {
/* 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);
......
......@@ -57,6 +57,7 @@ int fib_lookup(struct net *net, struct flowi *flp, struct fib_result *res)
{
struct fib_lookup_arg arg = {
.result = res,
.flags = FIB_LOOKUP_NOREF,
};
int err;
......@@ -94,7 +95,7 @@ static int fib4_rule_action(struct fib_rule *rule, struct flowi *flp,
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:
......
......@@ -148,6 +148,13 @@ static const struct
/* 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 @@ void free_fib_info(struct fib_info *fi)
} 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 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
nh->nh_scope = RT_SCOPE_LINK;
return 0;
}
rcu_read_lock();
{
struct flowi fl = {
.nl_u = {
......@@ -568,8 +576,10 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
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 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
goto out;
err = 0;
out:
fib_res_put(&res);
rcu_read_unlock();
return err;
} else {
struct in_device *in_dev;
......@@ -879,7 +889,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
/* 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 @@ int fib_semantic_match(struct list_head *head, const struct flowi *flp,
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;
}
......
......@@ -1342,7 +1342,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
/* 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 @@ static int check_leaf(struct trie *t, struct leaf *l,
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 @@ static int check_leaf(struct trie *t, struct leaf *l,
}
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 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi *flp,
/* 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 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi *flp,
}
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;
......
......@@ -1773,12 +1773,15 @@ void ip_rt_get_source(u8 *addr, struct rtable *rt)
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 @@ static int ip_mkroute_input(struct sk_buff *skb,
* 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 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
/*
* 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 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
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 @@ out: return err;
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 @@ out: return err;
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 @@ int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
}
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 @@ static int __mkroute_output(struct rtable **result,
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 @@ static int __mkroute_output(struct rtable **result,
* 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 @@ static int __mkroute_output(struct rtable **result,
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 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
struct fib_result res;
unsigned int flags = 0;
struct net_device *dev_out = NULL;
int free_res = 0;
int err;
......@@ -2636,15 +2630,12 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
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 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
make_route:
err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
if (free_res)
fib_res_put(&res);
out: return err;
}
......
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