diff options
author | Eric Dumazet <edumazet@google.com> | 2016-04-01 08:52:13 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2016-04-04 22:11:19 -0400 |
commit | ca065d0cf80fa547724440a8bf37f1e674d917c0 (patch) | |
tree | 6384df2fda5ff249da39464de7e7b9a079a794e6 /net/ipv6 | |
parent | a4298e4522d687a79af8f8fbb7eca68399ab2d81 (diff) |
udp: no longer use SLAB_DESTROY_BY_RCU
Tom Herbert would like not touching UDP socket refcnt for encapsulated
traffic. For this to happen, we need to use normal RCU rules, with a grace
period before freeing a socket. UDP sockets are not short lived in the
high usage case, so the added cost of call_rcu() should not be a concern.
This actually removes a lot of complexity in UDP stack.
Multicast receives no longer need to hold a bucket spinlock.
Note that ip early demux still needs to take a reference on the socket.
Same remark for functions used by xt_socket and xt_PROXY netfilter modules,
but this might be changed later.
Performance for a single UDP socket receiving flood traffic from
many RX queues/cpus.
Simple udp_rx using simple recvfrom() loop :
438 kpps instead of 374 kpps : 17 % increase of the peak rate.
v2: Addressed Willem de Bruijn feedback in multicast handling
- keep early demux break in __udp4_lib_demux_lookup()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Willem de Bruijn <willemb@google.com>
Tested-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r-- | net/ipv6/udp.c | 196 |
1 files changed, 64 insertions, 132 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index b772a7641fbd..78a7dfd12707 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -213,37 +213,28 @@ static struct sock *udp6_lib_lookup2(struct net *net, struct sk_buff *skb) { struct sock *sk, *result; - struct hlist_nulls_node *node; int score, badness, matches = 0, reuseport = 0; - bool select_ok = true; u32 hash = 0; -begin: result = NULL; badness = -1; - udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) { + udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) { score = compute_score2(sk, net, saddr, sport, daddr, hnum, dif); if (score > badness) { - result = sk; - badness = score; reuseport = sk->sk_reuseport; if (reuseport) { hash = udp6_ehashfn(net, daddr, hnum, saddr, sport); - if (select_ok) { - struct sock *sk2; - sk2 = reuseport_select_sock(sk, hash, skb, + result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); - if (sk2) { - result = sk2; - select_ok = false; - goto found; - } - } + if (result) + return result; matches = 1; } + result = sk; + badness = score; } else if (score == badness && reuseport) { matches++; if (reciprocal_scale(hash, matches) == 0) @@ -251,27 +242,10 @@ begin: hash = next_pseudo_random32(hash); } } - /* - * if the nulls value we got at the end of this lookup is - * not the expected one, we must restart lookup. - * We probably met an item that was moved to another chain. - */ - if (get_nulls_value(node) != slot2) - goto begin; - - if (result) { -found: - if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2))) - result = NULL; - else if (unlikely(compute_score2(result, net, saddr, sport, - daddr, hnum, dif) < badness)) { - sock_put(result); - goto begin; - } - } return result; } +/* rcu_read_lock() must be held */ struct sock *__udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport, const struct in6_addr *daddr, __be16 dport, @@ -279,15 +253,12 @@ struct sock *__udp6_lib_lookup(struct net *net, struct sk_buff *skb) { struct sock *sk, *result; - struct hlist_nulls_node *node; unsigned short hnum = ntohs(dport); unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask); struct udp_hslot *hslot2, *hslot = &udptable->hash[slot]; int score, badness, matches = 0, reuseport = 0; - bool select_ok = true; u32 hash = 0; - rcu_read_lock(); if (hslot->count > 10) { hash2 = udp6_portaddr_hash(net, daddr, hnum); slot2 = hash2 & udptable->mask; @@ -309,34 +280,26 @@ struct sock *__udp6_lib_lookup(struct net *net, &in6addr_any, hnum, dif, hslot2, slot2, skb); } - rcu_read_unlock(); return result; } begin: result = NULL; badness = -1; - sk_nulls_for_each_rcu(sk, node, &hslot->head) { + sk_for_each_rcu(sk, &hslot->head) { score = compute_score(sk, net, hnum, saddr, sport, daddr, dport, dif); if (score > badness) { - result = sk; - badness = score; reuseport = sk->sk_reuseport; if (reuseport) { hash = udp6_ehashfn(net, daddr, hnum, saddr, sport); - if (select_ok) { - struct sock *sk2; - - sk2 = reuseport_select_sock(sk, hash, skb, + result = reuseport_select_sock(sk, hash, skb, sizeof(struct udphdr)); - if (sk2) { - result = sk2; - select_ok = false; - goto found; - } - } + if (result) + return result; matches = 1; } + result = sk; + badness = score; } else if (score == badness && reuseport) { matches++; if (reciprocal_scale(hash, matches) == 0) @@ -344,25 +307,6 @@ begin: hash = next_pseudo_random32(hash); } } - /* - * if the nulls value we got at the end of this lookup is - * not the expected one, we must restart lookup. - * We probably met an item that was moved to another chain. - */ - if (get_nulls_value(node) != slot) - goto begin; - - if (result) { -found: - if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2))) - result = NULL; - else if (unlikely(compute_score(result, net, hnum, saddr, sport, - daddr, dport, dif) < badness)) { - sock_put(result); - goto begin; - } - } - rcu_read_unlock(); return result; } EXPORT_SYMBOL_GPL(__udp6_lib_lookup); @@ -382,12 +326,24 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb, udptable, skb); } +/* Must be called under rcu_read_lock(). + * Does increment socket refcount. + */ +#if IS_ENABLED(CONFIG_NETFILTER_XT_MATCH_SOCKET) || \ + IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TPROXY) struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport, const struct in6_addr *daddr, __be16 dport, int dif) { - return __udp6_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table, NULL); + struct sock *sk; + + sk = __udp6_lib_lookup(net, saddr, sport, daddr, dport, + dif, &udp_table, NULL); + if (sk && !atomic_inc_not_zero(&sk->sk_refcnt)) + sk = NULL; + return sk; } EXPORT_SYMBOL_GPL(udp6_lib_lookup); +#endif /* * This should be easy, if there is something there we @@ -585,7 +541,7 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt, sk->sk_err = err; sk->sk_error_report(sk); out: - sock_put(sk); + return; } static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) @@ -747,33 +703,6 @@ static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk, return true; } -static void flush_stack(struct sock **stack, unsigned int count, - struct sk_buff *skb, unsigned int final) -{ - struct sk_buff *skb1 = NULL; - struct sock *sk; - unsigned int i; - - for (i = 0; i < count; i++) { - sk = stack[i]; - if (likely(!skb1)) - skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC); - if (!skb1) { - atomic_inc(&sk->sk_drops); - UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS, - IS_UDPLITE(sk)); - UDP6_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, - IS_UDPLITE(sk)); - } - - if (skb1 && udpv6_queue_rcv_skb(sk, skb1) <= 0) - skb1 = NULL; - sock_put(sk); - } - if (unlikely(skb1)) - kfree_skb(skb1); -} - static void udp6_csum_zero_error(struct sk_buff *skb) { /* RFC 2460 section 8.1 says that we SHOULD log @@ -792,15 +721,15 @@ static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb, const struct in6_addr *saddr, const struct in6_addr *daddr, struct udp_table *udptable, int proto) { - struct sock *sk, *stack[256 / sizeof(struct sock *)]; + struct sock *sk, *first = NULL; const struct udphdr *uh = udp_hdr(skb); - struct hlist_nulls_node *node; unsigned short hnum = ntohs(uh->dest); struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum); - int dif = inet6_iif(skb); - unsigned int count = 0, offset = offsetof(typeof(*sk), sk_nulls_node); + unsigned int offset = offsetof(typeof(*sk), sk_node); unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10); - bool inner_flushed = false; + int dif = inet6_iif(skb); + struct hlist_node *node; + struct sk_buff *nskb; if (use_hash2) { hash2_any = udp6_portaddr_hash(net, &in6addr_any, hnum) & @@ -811,27 +740,32 @@ start_lookup: offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node); } - spin_lock(&hslot->lock); - sk_nulls_for_each_entry_offset(sk, node, &hslot->head, offset) { - if (__udp_v6_is_mcast_sock(net, sk, - uh->dest, daddr, - uh->source, saddr, - dif, hnum) && - /* If zero checksum and no_check is not on for - * the socket then skip it. - */ - (uh->check || udp_sk(sk)->no_check6_rx)) { - if (unlikely(count == ARRAY_SIZE(stack))) { - flush_stack(stack, count, skb, ~0); - inner_flushed = true; - count = 0; - } - stack[count++] = sk; - sock_hold(sk); + sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) { + if (!__udp_v6_is_mcast_sock(net, sk, uh->dest, daddr, + uh->source, saddr, dif, hnum)) + continue; + /* If zero checksum and no_check is not on for + * the socket then skip it. + */ + if (!uh->check && !udp_sk(sk)->no_check6_rx) + continue; + if (!first) { + first = sk; + continue; + } + nskb = skb_clone(skb, GFP_ATOMIC); + if (unlikely(!nskb)) { + atomic_inc(&sk->sk_drops); + UDP6_INC_STATS_BH(net, UDP_MIB_RCVBUFERRORS, + IS_UDPLITE(sk)); + UDP6_INC_STATS_BH(net, UDP_MIB_INERRORS, + IS_UDPLITE(sk)); + continue; } - } - spin_unlock(&hslot->lock); + if (udpv6_queue_rcv_skb(sk, nskb) > 0) + consume_skb(nskb); + } /* Also lookup *:port if we are using hash2 and haven't done so yet. */ if (use_hash2 && hash2 != hash2_any) { @@ -839,13 +773,13 @@ start_lookup: goto start_lookup; } - if (count) { - flush_stack(stack, count, skb, count - 1); + if (first) { + if (udpv6_queue_rcv_skb(first, skb) > 0) + consume_skb(skb); } else { - if (!inner_flushed) - UDP6_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI, - proto == IPPROTO_UDPLITE); - consume_skb(skb); + kfree_skb(skb); + UDP6_INC_STATS_BH(net, UDP_MIB_IGNOREDMULTI, + proto == IPPROTO_UDPLITE); } return 0; } @@ -853,10 +787,10 @@ start_lookup: int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, int proto) { + const struct in6_addr *saddr, *daddr; struct net *net = dev_net(skb->dev); - struct sock *sk; struct udphdr *uh; - const struct in6_addr *saddr, *daddr; + struct sock *sk; u32 ulen = 0; if (!pskb_may_pull(skb, sizeof(struct udphdr))) @@ -910,7 +844,6 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, int ret; if (!uh->check && !udp_sk(sk)->no_check6_rx) { - sock_put(sk); udp6_csum_zero_error(skb); goto csum_error; } @@ -920,7 +853,6 @@ int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable, ip6_compute_pseudo); ret = udpv6_queue_rcv_skb(sk, skb); - sock_put(sk); /* a return value > 0 means to resubmit the input */ if (ret > 0) |