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authorEric Dumazet <edumazet@google.com>2015-03-22 10:22:18 -0700
committerDavid S. Miller <davem@davemloft.net>2015-03-23 16:52:25 -0400
commit2b41fab70fc001d2acd89c0477d32feb8265bb32 (patch)
tree1597c834b5bc63933f5d3d1d62612319280e3fd0
parentMerge branch 'gigaset_modem_response' (diff)
downloadlinux-dev-2b41fab70fc001d2acd89c0477d32feb8265bb32.tar.xz
linux-dev-2b41fab70fc001d2acd89c0477d32feb8265bb32.zip
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>
-rw-r--r--net/ipv4/inet_connection_sock.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 844808d9337b..7d011e825c48 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -571,8 +571,9 @@ static void reqsk_timer_handler(unsigned long data)
struct inet_connection_sock *icsk = inet_csk(sk_listener);
struct request_sock_queue *queue = &icsk->icsk_accept_queue;
struct listen_sock *lopt = queue->listen_opt;
- int expire = 0, resend = 0;
+ int qlen, expire = 0, resend = 0;
int max_retries, thresh;
+ u8 defer_accept;
if (sk_listener->sk_state != TCP_LISTEN || !lopt) {
reqsk_put(req);
@@ -598,19 +599,21 @@ static void reqsk_timer_handler(unsigned long data)
* embrions; and abort old ones without pity, if old
* 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;
while (thresh > 2) {
- if (listen_sock_qlen(lopt) < young)
+ if (qlen < young)
break;
thresh--;
young <<= 1;
}
}
- if (queue->rskq_defer_accept)
- max_retries = queue->rskq_defer_accept;
- syn_ack_recalc(req, thresh, max_retries, queue->rskq_defer_accept,
+ defer_accept = READ_ONCE(queue->rskq_defer_accept);
+ if (defer_accept)
+ max_retries = defer_accept;
+ syn_ack_recalc(req, thresh, max_retries, defer_accept,
&expire, &resend);
req->rsk_ops->syn_ack_timeout(sk_listener, req);
if (!expire &&