diff options
| author | Andy Grover <andy.grover@oracle.com> | 2010-03-11 13:50:04 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-03-16 21:16:59 -0700 |
| commit | b98ba52f96e7cdb4dbe2b06bced83d95d94c9d02 (patch) | |
| tree | 72e22772c6326ff554bd030bda35abcb1526249e /net | |
| parent | 550a8002e4340eaf3bc333e33b59427e9c20272d (diff) | |
| download | lwn-b98ba52f96e7cdb4dbe2b06bced83d95d94c9d02.tar.gz lwn-b98ba52f96e7cdb4dbe2b06bced83d95d94c9d02.zip | |
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 <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/rds/af_rds.c | 7 | ||||
| -rw-r--r-- | net/rds/rds.h | 2 | ||||
| -rw-r--r-- | net/rds/send.c | 4 |
3 files changed, 11 insertions, 2 deletions
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; } diff --git a/net/rds/rds.h b/net/rds/rds.h index 85d6f897ecc7..4bec6e2ed495 100644 --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -388,6 +388,8 @@ struct rds_sock { /* flag indicating we were congested or not */ int rs_congested; + /* seen congestion (ENOBUFS) when sending? */ + int rs_seen_congestion; /* rs_lock protects all these adjacent members before the newline */ spinlock_t rs_lock; diff --git a/net/rds/send.c b/net/rds/send.c index 192a480076d0..51e2def50b12 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -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); ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs); - if (ret) + if (ret) { + rs->rs_seen_congestion = 1; goto out; + } while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port, dport, &queued)) { |