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 <edumazet@google.com>
Cc: Ying Cai <ycai@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index e62f047..80904df 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -476,65 +476,12 @@
}
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 @@
}
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 @@
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 @@
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);
}
-EXPORT_SYMBOL(reqsk_queue_hash_req);
+
+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_GPL(inet_csk_reqsk_queue_hash_add);
/**
* inet_csk_clone_lock - clone an inet socket, and lock its clone