From 079096f103faca2dd87342cca6f23d4b34da8871 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 2 Oct 2015 11:43:32 -0700 Subject: tcp/dccp: install syn_recv requests into ehash table In this patch, we insert request sockets into TCP/DCCP regular ehash table (where ESTABLISHED and TIMEWAIT sockets are) instead of using the per listener hash table. ACK packets find SYN_RECV pseudo sockets without having to find and lock the listener. In nominal conditions, this halves pressure on listener lock. Note that this will allow for SO_REUSEPORT refinements, so that we can select a listener using cpu/numa affinities instead of the prior 'consistent hash', since only SYN packets will apply this selection logic. We will shrink listen_sock in the following patch to ease code review. Signed-off-by: Eric Dumazet Cc: Ying Cai Cc: Willem de Bruijn Signed-off-by: David S. Miller --- net/ipv4/inet_connection_sock.c | 103 ++++++++-------------------------------- 1 file changed, 21 insertions(+), 82 deletions(-) (limited to 'net/ipv4/inet_connection_sock.c') diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index e62f04775c93..80904df02187 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -476,65 +476,12 @@ no_route: } EXPORT_SYMBOL_GPL(inet_csk_route_child_sock); -static inline u32 inet_synq_hash(const __be32 raddr, const __be16 rport, - const u32 rnd, const u32 synq_hsize) -{ - return jhash_2words((__force u32)raddr, (__force u32)rport, rnd) & (synq_hsize - 1); -} - #if IS_ENABLED(CONFIG_IPV6) #define AF_INET_FAMILY(fam) ((fam) == AF_INET) #else #define AF_INET_FAMILY(fam) true #endif -/* Note: this is temporary : - * req sock will no longer be in listener hash table -*/ -struct request_sock *inet_csk_search_req(struct sock *sk, - const __be16 rport, - const __be32 raddr, - const __be32 laddr) -{ - struct inet_connection_sock *icsk = inet_csk(sk); - struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; - struct request_sock *req; - u32 hash = inet_synq_hash(raddr, rport, lopt->hash_rnd, - lopt->nr_table_entries); - - spin_lock(&icsk->icsk_accept_queue.syn_wait_lock); - for (req = lopt->syn_table[hash]; req != NULL; req = req->dl_next) { - const struct inet_request_sock *ireq = inet_rsk(req); - - if (ireq->ir_rmt_port == rport && - ireq->ir_rmt_addr == raddr && - ireq->ir_loc_addr == laddr && - AF_INET_FAMILY(req->rsk_ops->family)) { - atomic_inc(&req->rsk_refcnt); - WARN_ON(req->sk); - break; - } - } - spin_unlock(&icsk->icsk_accept_queue.syn_wait_lock); - - return req; -} -EXPORT_SYMBOL_GPL(inet_csk_search_req); - -void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, - unsigned long timeout) -{ - struct inet_connection_sock *icsk = inet_csk(sk); - struct listen_sock *lopt = icsk->icsk_accept_queue.listen_opt; - const u32 h = inet_synq_hash(inet_rsk(req)->ir_rmt_addr, - inet_rsk(req)->ir_rmt_port, - lopt->hash_rnd, lopt->nr_table_entries); - - reqsk_queue_hash_req(&icsk->icsk_accept_queue, h, req, timeout); - inet_csk_reqsk_queue_added(sk); -} -EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); - /* Only thing we need from tcp.h */ extern int sysctl_tcp_synack_retries; @@ -571,26 +518,20 @@ int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req) } EXPORT_SYMBOL(inet_rtx_syn_ack); -/* return true if req was found in the syn_table[] */ +/* return true if req was found in the ehash table */ static bool reqsk_queue_unlink(struct request_sock_queue *queue, struct request_sock *req) { - struct listen_sock *lopt = queue->listen_opt; - struct request_sock **prev; - bool found = false; + struct inet_hashinfo *hashinfo = req_to_sk(req)->sk_prot->h.hashinfo; + spinlock_t *lock; + bool found; - spin_lock(&queue->syn_wait_lock); + lock = inet_ehash_lockp(hashinfo, req->rsk_hash); - for (prev = &lopt->syn_table[req->rsk_hash]; *prev != NULL; - prev = &(*prev)->dl_next) { - if (*prev == req) { - *prev = req->dl_next; - found = true; - break; - } - } + spin_lock(lock); + found = __sk_nulls_del_node_init_rcu(req_to_sk(req)); + spin_unlock(lock); - spin_unlock(&queue->syn_wait_lock); if (timer_pending(&req->rsk_timer) && del_timer_sync(&req->rsk_timer)) reqsk_put(req); return found; @@ -616,10 +557,8 @@ static void reqsk_timer_handler(unsigned long data) int max_retries, thresh; u8 defer_accept; - if (sk_listener->sk_state != TCP_LISTEN || !lopt) { - reqsk_put(req); - return; - } + if (sk_listener->sk_state != TCP_LISTEN || !lopt) + goto drop; max_retries = icsk->icsk_syn_retries ? : sysctl_tcp_synack_retries; thresh = max_retries; @@ -669,36 +608,36 @@ static void reqsk_timer_handler(unsigned long data) mod_timer_pinned(&req->rsk_timer, jiffies + timeo); return; } +drop: inet_csk_reqsk_queue_drop(sk_listener, req); reqsk_put(req); } -void reqsk_queue_hash_req(struct request_sock_queue *queue, - u32 hash, struct request_sock *req, - unsigned long timeout) +static void reqsk_queue_hash_req(struct request_sock *req, + unsigned long timeout) { - struct listen_sock *lopt = queue->listen_opt; - req->num_retrans = 0; req->num_timeout = 0; req->sk = NULL; setup_timer(&req->rsk_timer, reqsk_timer_handler, (unsigned long)req); mod_timer_pinned(&req->rsk_timer, jiffies + timeout); - req->rsk_hash = hash; + inet_ehash_insert(req_to_sk(req), NULL); /* before letting lookups find us, make sure all req fields * are committed to memory and refcnt initialized. */ smp_wmb(); atomic_set(&req->rsk_refcnt, 2); +} - spin_lock(&queue->syn_wait_lock); - req->dl_next = lopt->syn_table[hash]; - lopt->syn_table[hash] = req; - spin_unlock(&queue->syn_wait_lock); +void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req, + unsigned long timeout) +{ + reqsk_queue_hash_req(req, timeout); + inet_csk_reqsk_queue_added(sk); } -EXPORT_SYMBOL(reqsk_queue_hash_req); +EXPORT_SYMBOL_GPL(inet_csk_reqsk_queue_hash_add); /** * inet_csk_clone_lock - clone an inet socket, and lock its clone -- cgit v1.2.3