Hi, rds_tcp_dev_event() is the last user of NETDEV_UNREGISTER_FINAL stage. If we rework it, we'll be able to kill the stage, and this will decrease the number of rtnl_lock() we take during generic net device unregistration. This is very hot path for namespaces. 467fa15356acf by Sowmini Varadhan added NETDEV_UNREGISTER_FINAL dependence with the commentary: /* rds-tcp registers as a pernet subys, so the ->exit will only * get invoked after network acitivity has quiesced. We need to * clean up all sockets to quiesce network activity, and use * the unregistration of the per-net loopback device as a trigger * to start that cleanup. */ It seems all the protocols pernet subsystems meet this situation, but they solve it in generic way. What does rds so specific have? This commit makes event handler to iterate rds_tcp_conn_list and kill them. If we change the stage to NETDEV_UNREGISTER, what will change? Can unregistered loopback device on dead net add new items to rds_tcp_conn_list? How it's possible? What the problem is to move rds_tcp_kill_sock() into pernet subsys exit? Kirill --- net/rds/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/rds/tcp.c b/net/rds/tcp.c index eb04e7fa2467..4c6db9cb6261 100644 --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -567,7 +567,7 @@ static int rds_tcp_dev_event(struct notifier_block *this, * the unregistration of the per-net loopback device as a trigger * to start that cleanup. */ - if (event == NETDEV_UNREGISTER_FINAL && + if (event == NETDEV_UNREGISTER && dev->ifindex == LOOPBACK_IFINDEX) rds_tcp_kill_sock(dev_net(dev)); -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
