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Commit b98ba52f authored by Andy Grover's avatar Andy Grover Committed by David S. Miller
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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: default avatarAndy Grover <andy.grover@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 550a8002

net/rds/af_rds.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -159,6 +159,7 @@ static unsigned int rds_poll(struct file *file, struct socket *sock, 




	poll_wait(file, sk->sk_sleep, wait);

	poll_wait(file, sk->sk_sleep, wait);





	if (rs->rs_seen_congestion)

		poll_wait(file, &rds_poll_waitq, wait);

		poll_wait(file, &rds_poll_waitq, wait);





	read_lock_irqsave(&rs->rs_recv_lock, flags);

	read_lock_irqsave(&rs->rs_recv_lock, flags);
@@ -181,6 +182,10 @@ static unsigned int rds_poll(struct file *file, struct socket *sock, 
		mask |= (POLLOUT | POLLWRNORM);

		mask |= (POLLOUT | POLLWRNORM);

	read_unlock_irqrestore(&rs->rs_recv_lock, flags);

	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;

	return mask;

}

}

net/rds/rds.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -388,6 +388,8 @@ struct rds_sock { 




	/* flag indicating we were congested or not */

	/* flag indicating we were congested or not */

	int			rs_congested;

	int			rs_congested;

	/* seen congestion (ENOBUFS) when sending? */

	int			rs_seen_congestion;





	/* rs_lock protects all these adjacent members before the newline */

	/* rs_lock protects all these adjacent members before the newline */

	spinlock_t		rs_lock;

	spinlock_t		rs_lock;

net/rds/send.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -894,8 +894,10 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, 
		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);

		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);





	ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);

	ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);

	if (ret)

	if (ret) {

		rs->rs_seen_congestion = 1;

		goto out;

		goto out;

	}





	while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,

	while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,

				  dport, &queued)) {

				  dport, &queued)) {