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inet: cache listen_sock_qlen() and read rskq_defer_accept once 

Cache listen_sock_qlen() to limit false sharing, and read
rskq_defer_accept once as it might change under us.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-03-22 10:22:18 -07:00 committed by David S. Miller
parent c9231f8247
commit 2b41fab70f
1 changed files with 9 additions and 6 deletions
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15
net/ipv4/inet_connection_sock.c
View File

@ -571,8 +571,9 @@ static void reqsk_timer_handler(unsigned long data)
struct inet_connection_sock *icsk = inet_csk(sk_listener); struct inet_connection_sock *icsk = inet_csk(sk_listener);
struct request_sock_queue *queue = &icsk->icsk_accept_queue; struct request_sock_queue *queue = &icsk->icsk_accept_queue;
struct listen_sock *lopt = queue->listen_opt; struct listen_sock *lopt = queue->listen_opt;
int expire = 0, resend = 0; int qlen, expire = 0, resend = 0;
int max_retries, thresh; int max_retries, thresh;
u8 defer_accept;
if (sk_listener->sk_state != TCP_LISTEN || !lopt) { if (sk_listener->sk_state != TCP_LISTEN || !lopt) {
reqsk_put(req); reqsk_put(req);
@ -598,19 +599,21 @@ static void reqsk_timer_handler(unsigned long data)
* embrions; and abort old ones without pity, if old * embrions; and abort old ones without pity, if old
* ones are about to clog our table. * ones are about to clog our table.
*/ */
if (listen_sock_qlen(lopt) >> (lopt->max_qlen_log - 1)) { qlen = listen_sock_qlen(lopt);
if (qlen >> (lopt->max_qlen_log - 1)) {
int young = listen_sock_young(lopt) << 1; int young = listen_sock_young(lopt) << 1;
while (thresh > 2) { while (thresh > 2) {
if (listen_sock_qlen(lopt) < young) if (qlen < young)
break; break;
thresh--; thresh--;
young <<= 1; young <<= 1;
} }
} }
if (queue->rskq_defer_accept) defer_accept = READ_ONCE(queue->rskq_defer_accept);
max_retries = queue->rskq_defer_accept; if (defer_accept)
syn_ack_recalc(req, thresh, max_retries, queue->rskq_defer_accept, max_retries = defer_accept;
syn_ack_recalc(req, thresh, max_retries, defer_accept,
&expire, &resend); &expire, &resend);
req->rsk_ops->syn_ack_timeout(sk_listener, req); req->rsk_ops->syn_ack_timeout(sk_listener, req);
if (!expire && if (!expire &&