net: listening_hash get a spinlock per bucket
This patch prepares RCU migration of listening_hash table for TCP/DCCP protocols. listening_hash table being small (32 slots per protocol), we add a spinlock for each slot, instead of a single rwlock for whole table. This should reduce hold time of readers, and writers concurrency. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
David S. Miller
parent
d8b83c57a7
commit
5caea4ea70
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@ -99,6 +99,11 @@ struct inet_bind_hashbucket {
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struct hlist_head chain;
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};
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struct inet_listen_hashbucket {
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spinlock_t lock;
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struct hlist_head head;
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};
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/* This is for listening sockets, thus all sockets which possess wildcards. */
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#define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */
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@ -123,22 +128,21 @@ struct inet_hashinfo {
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unsigned int bhash_size;
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/* Note : 4 bytes padding on 64 bit arches */
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/* All sockets in TCP_LISTEN state will be in here. This is the only
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* table where wildcard'd TCP sockets can exist. Hash function here
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* is just local port number.
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*/
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struct hlist_head listening_hash[INET_LHTABLE_SIZE];
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struct kmem_cache *bind_bucket_cachep;
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/* All the above members are written once at bootup and
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* never written again _or_ are predominantly read-access.
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*
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* Now align to a new cache line as all the following members
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* are often dirty.
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* might be often dirty.
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*/
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rwlock_t lhash_lock ____cacheline_aligned;
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atomic_t lhash_users;
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wait_queue_head_t lhash_wait;
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struct kmem_cache *bind_bucket_cachep;
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/* All sockets in TCP_LISTEN state will be in here. This is the only
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* table where wildcard'd TCP sockets can exist. Hash function here
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* is just local port number.
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*/
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struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE]
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____cacheline_aligned_in_smp;
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};
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static inline struct inet_ehash_bucket *inet_ehash_bucket(
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@ -236,26 +240,7 @@ extern void __inet_inherit_port(struct sock *sk, struct sock *child);
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extern void inet_put_port(struct sock *sk);
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extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);
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/*
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* - We may sleep inside this lock.
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* - If sleeping is not required (or called from BH),
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* use plain read_(un)lock(&inet_hashinfo.lhash_lock).
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*/
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static inline void inet_listen_lock(struct inet_hashinfo *hashinfo)
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{
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/* read_lock synchronizes to candidates to writers */
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read_lock(&hashinfo->lhash_lock);
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atomic_inc(&hashinfo->lhash_users);
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read_unlock(&hashinfo->lhash_lock);
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}
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static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
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{
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if (atomic_dec_and_test(&hashinfo->lhash_users))
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wake_up(&hashinfo->lhash_wait);
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}
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void inet_hashinfo_init(struct inet_hashinfo *h);
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extern void __inet_hash_nolisten(struct sock *sk);
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extern void inet_hash(struct sock *sk);
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@ -44,12 +44,7 @@ atomic_t dccp_orphan_count = ATOMIC_INIT(0);
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EXPORT_SYMBOL_GPL(dccp_orphan_count);
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struct inet_hashinfo __cacheline_aligned dccp_hashinfo = {
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.lhash_lock = RW_LOCK_UNLOCKED,
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.lhash_users = ATOMIC_INIT(0),
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.lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(dccp_hashinfo.lhash_wait),
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};
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struct inet_hashinfo dccp_hashinfo;
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EXPORT_SYMBOL_GPL(dccp_hashinfo);
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/* the maximum queue length for tx in packets. 0 is no limit */
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@ -1030,6 +1025,7 @@ static int __init dccp_init(void)
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BUILD_BUG_ON(sizeof(struct dccp_skb_cb) >
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FIELD_SIZEOF(struct sk_buff, cb));
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inet_hashinfo_init(&dccp_hashinfo);
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dccp_hashinfo.bind_bucket_cachep =
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kmem_cache_create("dccp_bind_bucket",
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sizeof(struct inet_bind_bucket), 0,
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@ -718,13 +718,15 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
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if (!(r->idiag_states & (TCPF_LISTEN | TCPF_SYN_RECV)))
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goto skip_listen_ht;
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inet_listen_lock(hashinfo);
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for (i = s_i; i < INET_LHTABLE_SIZE; i++) {
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struct sock *sk;
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struct hlist_node *node;
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struct inet_listen_hashbucket *ilb;
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num = 0;
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sk_for_each(sk, node, &hashinfo->listening_hash[i]) {
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ilb = &hashinfo->listening_hash[i];
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spin_lock_bh(&ilb->lock);
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sk_for_each(sk, node, &ilb->head) {
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struct inet_sock *inet = inet_sk(sk);
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if (num < s_num) {
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@ -742,7 +744,7 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
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goto syn_recv;
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if (inet_csk_diag_dump(sk, skb, cb) < 0) {
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inet_listen_unlock(hashinfo);
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spin_unlock_bh(&ilb->lock);
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goto done;
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}
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@ -751,7 +753,7 @@ syn_recv:
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goto next_listen;
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if (inet_diag_dump_reqs(skb, sk, cb) < 0) {
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inet_listen_unlock(hashinfo);
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spin_unlock_bh(&ilb->lock);
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goto done;
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}
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@ -760,12 +762,12 @@ next_listen:
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cb->args[4] = 0;
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++num;
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}
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spin_unlock_bh(&ilb->lock);
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s_num = 0;
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cb->args[3] = 0;
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cb->args[4] = 0;
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}
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inet_listen_unlock(hashinfo);
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skip_listen_ht:
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cb->args[0] = 1;
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s_i = num = s_num = 0;
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@ -110,35 +110,6 @@ void __inet_inherit_port(struct sock *sk, struct sock *child)
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EXPORT_SYMBOL_GPL(__inet_inherit_port);
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/*
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* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
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* Look, when several writers sleep and reader wakes them up, all but one
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* immediately hit write lock and grab all the cpus. Exclusive sleep solves
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* this, _but_ remember, it adds useless work on UP machines (wake up each
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* exclusive lock release). It should be ifdefed really.
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*/
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void inet_listen_wlock(struct inet_hashinfo *hashinfo)
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__acquires(hashinfo->lhash_lock)
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{
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write_lock(&hashinfo->lhash_lock);
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if (atomic_read(&hashinfo->lhash_users)) {
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DEFINE_WAIT(wait);
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for (;;) {
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prepare_to_wait_exclusive(&hashinfo->lhash_wait,
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&wait, TASK_UNINTERRUPTIBLE);
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if (!atomic_read(&hashinfo->lhash_users))
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break;
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write_unlock_bh(&hashinfo->lhash_lock);
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schedule();
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write_lock_bh(&hashinfo->lhash_lock);
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}
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finish_wait(&hashinfo->lhash_wait, &wait);
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}
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}
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/*
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* Don't inline this cruft. Here are some nice properties to exploit here. The
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* BSD API does not allow a listening sock to specify the remote port nor the
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@ -191,25 +162,25 @@ struct sock *__inet_lookup_listener(struct net *net,
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const int dif)
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{
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struct sock *sk = NULL;
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const struct hlist_head *head;
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struct inet_listen_hashbucket *ilb;
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read_lock(&hashinfo->lhash_lock);
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head = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
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if (!hlist_empty(head)) {
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const struct inet_sock *inet = inet_sk((sk = __sk_head(head)));
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ilb = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
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spin_lock(&ilb->lock);
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if (!hlist_empty(&ilb->head)) {
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const struct inet_sock *inet = inet_sk((sk = __sk_head(&ilb->head)));
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if (inet->num == hnum && !sk->sk_node.next &&
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(!inet->rcv_saddr || inet->rcv_saddr == daddr) &&
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(sk->sk_family == PF_INET || !ipv6_only_sock(sk)) &&
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!sk->sk_bound_dev_if && net_eq(sock_net(sk), net))
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goto sherry_cache;
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sk = inet_lookup_listener_slow(net, head, daddr, hnum, dif);
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sk = inet_lookup_listener_slow(net, &ilb->head, daddr, hnum, dif);
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}
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if (sk) {
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sherry_cache:
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sock_hold(sk);
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}
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read_unlock(&hashinfo->lhash_lock);
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spin_unlock(&ilb->lock);
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return sk;
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}
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EXPORT_SYMBOL_GPL(__inet_lookup_listener);
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@ -389,8 +360,7 @@ EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
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static void __inet_hash(struct sock *sk)
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{
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struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
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struct hlist_head *list;
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rwlock_t *lock;
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struct inet_listen_hashbucket *ilb;
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if (sk->sk_state != TCP_LISTEN) {
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__inet_hash_nolisten(sk);
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@ -398,14 +368,12 @@ static void __inet_hash(struct sock *sk)
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}
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WARN_ON(!sk_unhashed(sk));
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list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
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lock = &hashinfo->lhash_lock;
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ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
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inet_listen_wlock(hashinfo);
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__sk_add_node(sk, list);
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spin_lock(&ilb->lock);
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__sk_add_node(sk, &ilb->head);
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sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
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write_unlock(lock);
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wake_up(&hashinfo->lhash_wait);
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spin_unlock(&ilb->lock);
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}
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void inet_hash(struct sock *sk)
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@ -420,29 +388,27 @@ EXPORT_SYMBOL_GPL(inet_hash);
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void inet_unhash(struct sock *sk)
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{
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rwlock_t *lock;
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struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
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if (sk_unhashed(sk))
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goto out;
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return;
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if (sk->sk_state == TCP_LISTEN) {
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local_bh_disable();
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inet_listen_wlock(hashinfo);
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lock = &hashinfo->lhash_lock;
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struct inet_listen_hashbucket *ilb;
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ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
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spin_lock_bh(&ilb->lock);
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if (__sk_del_node_init(sk))
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sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
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spin_unlock_bh(&ilb->lock);
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} else {
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lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
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rwlock_t *lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
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write_lock_bh(lock);
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if (__sk_nulls_del_node_init_rcu(sk))
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sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
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write_unlock_bh(lock);
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}
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write_unlock_bh(lock);
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out:
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if (sk->sk_state == TCP_LISTEN)
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wake_up(&hashinfo->lhash_wait);
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}
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EXPORT_SYMBOL_GPL(inet_unhash);
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@ -556,3 +522,13 @@ int inet_hash_connect(struct inet_timewait_death_row *death_row,
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}
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EXPORT_SYMBOL_GPL(inet_hash_connect);
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void inet_hashinfo_init(struct inet_hashinfo *h)
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{
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int i;
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for (i = 0; i < INET_LHTABLE_SIZE; i++)
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spin_lock_init(&h->listening_hash[i].lock);
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}
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EXPORT_SYMBOL_GPL(inet_hashinfo_init);
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@ -97,11 +97,7 @@ struct tcp_md5sig_key *tcp_v4_md5_do_lookup(struct sock *sk, __be32 addr)
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}
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#endif
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struct inet_hashinfo __cacheline_aligned tcp_hashinfo = {
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.lhash_lock = __RW_LOCK_UNLOCKED(tcp_hashinfo.lhash_lock),
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.lhash_users = ATOMIC_INIT(0),
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.lhash_wait = __WAIT_QUEUE_HEAD_INITIALIZER(tcp_hashinfo.lhash_wait),
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};
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struct inet_hashinfo tcp_hashinfo;
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static inline __u32 tcp_v4_init_sequence(struct sk_buff *skb)
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{
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@ -1874,15 +1870,18 @@ static void *listening_get_next(struct seq_file *seq, void *cur)
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struct inet_connection_sock *icsk;
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struct hlist_node *node;
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struct sock *sk = cur;
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struct inet_listen_hashbucket *ilb;
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struct tcp_iter_state *st = seq->private;
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struct net *net = seq_file_net(seq);
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if (!sk) {
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st->bucket = 0;
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sk = sk_head(&tcp_hashinfo.listening_hash[0]);
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ilb = &tcp_hashinfo.listening_hash[0];
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spin_lock_bh(&ilb->lock);
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sk = sk_head(&ilb->head);
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goto get_sk;
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}
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ilb = &tcp_hashinfo.listening_hash[st->bucket];
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++st->num;
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if (st->state == TCP_SEQ_STATE_OPENREQ) {
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@ -1932,8 +1931,11 @@ start_req:
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}
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read_unlock_bh(&icsk->icsk_accept_queue.syn_wait_lock);
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}
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spin_unlock_bh(&ilb->lock);
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if (++st->bucket < INET_LHTABLE_SIZE) {
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sk = sk_head(&tcp_hashinfo.listening_hash[st->bucket]);
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ilb = &tcp_hashinfo.listening_hash[st->bucket];
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spin_lock_bh(&ilb->lock);
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sk = sk_head(&ilb->head);
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goto get_sk;
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}
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cur = NULL;
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@ -2066,12 +2068,10 @@ static void *tcp_get_idx(struct seq_file *seq, loff_t pos)
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void *rc;
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struct tcp_iter_state *st = seq->private;
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inet_listen_lock(&tcp_hashinfo);
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st->state = TCP_SEQ_STATE_LISTENING;
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rc = listening_get_idx(seq, &pos);
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if (!rc) {
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inet_listen_unlock(&tcp_hashinfo);
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st->state = TCP_SEQ_STATE_ESTABLISHED;
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rc = established_get_idx(seq, pos);
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}
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@ -2103,7 +2103,6 @@ static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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case TCP_SEQ_STATE_LISTENING:
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rc = listening_get_next(seq, v);
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if (!rc) {
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inet_listen_unlock(&tcp_hashinfo);
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st->state = TCP_SEQ_STATE_ESTABLISHED;
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rc = established_get_first(seq);
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}
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@ -2130,7 +2129,7 @@ static void tcp_seq_stop(struct seq_file *seq, void *v)
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}
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case TCP_SEQ_STATE_LISTENING:
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if (v != SEQ_START_TOKEN)
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inet_listen_unlock(&tcp_hashinfo);
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spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock);
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break;
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case TCP_SEQ_STATE_TIME_WAIT:
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case TCP_SEQ_STATE_ESTABLISHED:
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@ -2405,6 +2404,7 @@ static struct pernet_operations __net_initdata tcp_sk_ops = {
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void __init tcp_v4_init(void)
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{
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inet_hashinfo_init(&tcp_hashinfo);
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if (register_pernet_device(&tcp_sk_ops))
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panic("Failed to create the TCP control socket.\n");
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}
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@ -25,30 +25,30 @@
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void __inet6_hash(struct sock *sk)
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{
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struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
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rwlock_t *lock;
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WARN_ON(!sk_unhashed(sk));
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if (sk->sk_state == TCP_LISTEN) {
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struct hlist_head *list;
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struct inet_listen_hashbucket *ilb;
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list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
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lock = &hashinfo->lhash_lock;
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inet_listen_wlock(hashinfo);
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__sk_add_node(sk, list);
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ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
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spin_lock(&ilb->lock);
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__sk_add_node(sk, &ilb->head);
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spin_unlock(&ilb->lock);
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} else {
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unsigned int hash;
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struct hlist_nulls_head *list;
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rwlock_t *lock;
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sk->sk_hash = hash = inet6_sk_ehashfn(sk);
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list = &inet_ehash_bucket(hashinfo, hash)->chain;
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lock = inet_ehash_lockp(hashinfo, hash);
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write_lock(lock);
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__sk_nulls_add_node_rcu(sk, list);
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write_unlock(lock);
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}
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sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
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write_unlock(lock);
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}
|
||||
EXPORT_SYMBOL(__inet6_hash);
|
||||
|
||||
|
|
@ -126,10 +126,11 @@ struct sock *inet6_lookup_listener(struct net *net,
|
|||
const struct hlist_node *node;
|
||||
struct sock *result = NULL;
|
||||
int score, hiscore = 0;
|
||||
struct inet_listen_hashbucket *ilb;
|
||||
|
||||
read_lock(&hashinfo->lhash_lock);
|
||||
sk_for_each(sk, node,
|
||||
&hashinfo->listening_hash[inet_lhashfn(net, hnum)]) {
|
||||
ilb = &hashinfo->listening_hash[inet_lhashfn(net, hnum)];
|
||||
spin_lock(&ilb->lock);
|
||||
sk_for_each(sk, node, &ilb->head) {
|
||||
if (net_eq(sock_net(sk), net) && inet_sk(sk)->num == hnum &&
|
||||
sk->sk_family == PF_INET6) {
|
||||
const struct ipv6_pinfo *np = inet6_sk(sk);
|
||||
|
|
@ -157,7 +158,7 @@ struct sock *inet6_lookup_listener(struct net *net,
|
|||
}
|
||||
if (result)
|
||||
sock_hold(result);
|
||||
read_unlock(&hashinfo->lhash_lock);
|
||||
spin_unlock(&ilb->lock);
|
||||
return result;
|
||||
}
|
||||
|
||||
|
|
|
|||
Reference in New Issue