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authorAndy Grover <andy.grover@oracle.com>2010-03-11 16:50:04 +0300
committerDavid S. Miller <davem@davemloft.net>2010-03-17 07:16:59 +0300
commitb98ba52f96e7cdb4dbe2b06bced83d95d94c9d02 (patch)
tree72e22772c6326ff554bd030bda35abcb1526249e /net/rds/af_rds.c
parent550a8002e4340eaf3bc333e33b59427e9c20272d (diff)
downloadlinux-b98ba52f96e7cdb4dbe2b06bced83d95d94c9d02.tar.xz
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/rds/af_rds.c')
-rw-r--r--net/rds/af_rds.c7
1 files changed, 6 insertions, 1 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;
}