On 04/08/2017 02:18 PM, Roopa Prabhu wrote: > On 4/8/17, 11:13 AM, David Ahern wrote: >> On 4/8/17 2:06 PM, Roopa Prabhu wrote: >>> On 4/7/17, 2:25 PM, David Ahern wrote: >>>> Changing MTU on a link currently causes 3 messages to be sent to userspace: >>>> >>>> [LINK]11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1490 qdisc noqueue >>>> state UNKNOWN group default event PRE_CHANGE_MTU >>>> link/ether f2:52:5c:6d:21:f3 brd ff:ff:ff:ff:ff:ff >>>> >>>> [LINK]11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue >>>> state UNKNOWN group default event CHANGE_MTU >>>> link/ether f2:52:5c:6d:21:f3 brd ff:ff:ff:ff:ff:ff >>>> >>>> [LINK]11: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue >>>> state UNKNOWN group default >>>> link/ether f2:52:5c:6d:21:f3 brd ff:ff:ff:ff:ff:ff >>>> >>>> Remove the PRE_CHANGE_MTU and CHANGE_MTU messages. >>>> >>>> >>> This change is good... multiple notifications for the same event does not >>> help in large scale links setups. However, this >>> reverts what vlad was trying to do with his patchset. Vlad's patch-set >>> relies on the rtnl notifications generated from >>> notifiers (rtnetlink_event) to add specific event (IFLA_EVENT) in >>> notifications. >>> >>> The third notification in your example above is the correct one and is an >>> aggregate notification for a set of changes, but >>> it cannot really fill in all types of events in the single IFLA_EVENT >>> attribute as it stands today. IFLA_EVENT should be >>> a bitmask to include all events in this case (i had indicated this in vlads >>> first version). >>> >> Agreed. I think it would be best to revert def12888c161 before the UAPI >> goes out. >> >> The change can instead add the IFLA_EVENT as a bitmask mentioned here to >> note the changes in a setlink. On top of that, remove the notifications >> for the events I mentioned in this set to reduce the overhead on userspace. > > ack >
OK, so this will work for the events that are generated as a result of device state change (like mtu, address, and others). However, the original event data may be needed for other events that may be of use to userspace like NETDEV_NOTIFY_PEERS and NETDEV_RESEND_IGMP (possibly others...) -vlad
