On 4/8/17 9:36 PM, Vlad Yasevich wrote: > On 04/07/2017 05:25 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. > Actually, I have plans for the CHANGE_MTU event. The last message is not an > event. If you > remove the event, it is much harder to track mtu changes.
it is a set of redundant messages. Roopa suggested using a bitmask for the events changed by do_setlink which gets added to the last message seen above. In doing so you only generate 1 message. The above causes libnl (for example): - message 1: delete dummy1 from its cache and re-create it - message 2: delete dummy1 from its cache and re-create it - message 3: delete dummy1 from its cache and re-create it All you need is a single message at the end with an attribute that says "MTU changed"
