On 3/14/16, 12:56 PM, David Miller wrote: > From: Jiri Pirko <j...@resnulli.us> > Date: Mon, 14 Mar 2016 20:04:35 +0100 > >> I believe that using *any* structs to send over netlink is a mistake. >> Netlink is capable to transfer everything using attrs. Easy to compose, >> easy to parse. easy to extend. Couple of more bytes in the message? So what? >> For newly introduced things, I suggest to do this properly. > It is not so straight-forward. > > What to put into the header is a tradeoff. > > The most basic use cases should be as efficient as possible, and if we > can put reasonable knobs into the base commend header we should do that > as avoiding attribute processing makes things faster. yes, i have recently realized this after looking at all other message types and the userspace part of it. It does make the default message much simpler. > > And I think in this case it is reasonable to put the mask in there. > > The only problem I see with this series is the naming of the netlink > command (it isn't a "new" operation, and the "del" is unused). I just replied to the other responses on this: I did declare all three because rtnetlink_rcv_msg seems to expect the get message at a particular offset (when it derives kind from nlmsg_type). But, i can fix it accordingly. > > Maybe the suggestion to use just "GET" as the name is ok. I am thinking RTM_NEWSTATS is ok here. Because from userspace you are looking at message per interface as a separate stats object. It also adheres to existing convention.
Besides, jamals original request/suggestion also had periodic stats notification to user-space..., in which case it would be more appropriate to use RTM_NEWSTATS (if we implement it in the future ofcourse). And from userspace perspective, dumps and notifications should come in with the same msg type. userspace sees it as a stats message and does not care if it came as part of a dump or a notification. also, user space netlink caches expect this (i work with libnl a lot and it is based on this assumption). so, RTM_NEWSTATS seems more appropriate here. But, if you have stronger reasons for RTM_GETSTATS, sure, pls let me know. Thanks, Roopa
