From b98ba52f96e7cdb4dbe2b06bced83d95d94c9d02 Mon Sep 17 00:00:00 2001 From: Andy Grover Date: Thu, 11 Mar 2010 13:50:04 +0000 Subject: RDS: only put sockets that have seen congestion on the poll_waitq rds_poll_waitq's listeners will be awoken if we receive a congestion notification. Bad performance may result because *all* polled sockets contend for this single lock. However, it should not be necessary to wake pollers when a congestion update arrives if they have never experienced congestion, and not putting these on the waitq will hopefully greatly reduce contention. Signed-off-by: Andy Grover Signed-off-by: David S. Miller --- net/rds/af_rds.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'net/rds/af_rds.c') diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c index 853c52be781f..937ecda4abe7 100644 --- a/net/rds/af_rds.c +++ b/net/rds/af_rds.c @@ -159,7 +159,8 @@ static unsigned int rds_poll(struct file *file, struct socket *sock, poll_wait(file, sk->sk_sleep, wait); - poll_wait(file, &rds_poll_waitq, wait); + if (rs->rs_seen_congestion) + poll_wait(file, &rds_poll_waitq, wait); read_lock_irqsave(&rs->rs_recv_lock, flags); if (!rs->rs_cong_monitor) { @@ -181,6 +182,10 @@ static unsigned int rds_poll(struct file *file, struct socket *sock, mask |= (POLLOUT | POLLWRNORM); read_unlock_irqrestore(&rs->rs_recv_lock, flags); + /* clear state any time we wake a seen-congested socket */ + if (mask) + rs->rs_seen_congestion = 0; + return mask; } -- cgit v1.2.3-59-g8ed1b