rds: Use RCU for the bind lookup searches

The RDS bind lookups are somewhat expensive in terms of CPU
time and locking overhead.  This commit changes them into a
faster RCU based hash tree instead of the rbtrees they were using
before.

On large NUMA systems it is a significant improvement.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index ef09340cf7a..f16d2a92cb8 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -72,7 +72,15 @@ static int rds_release(struct socket *sock)
          * with the socket. */
         rds_clear_recv_queue(rs);
         rds_cong_remove_socket(rs);
+
+        /*
+         * the binding lookup hash uses rcu, we need to
+         * make sure we sychronize_rcu before we free our
+         * entry
+         */
         rds_remove_bound(rs);
+        synchronize_rcu();
+
         rds_send_drop_to(rs, NULL);
         rds_rdma_drop_keys(rs);
         rds_notify_queue_get(rs, NULL);