Subject: Re: Q: netdev: generate kobject uevent on network events.

From: Dan Williams <[email-masked]>
Date: Wed, 09 Dec 2009 11:21:26 -0800

On Wed, 2009-12-09 at 19:46 +0100, Kay Sievers wrote:
> On Wed, Dec 9, 2009 at 18:02, Johannes Stezenbach <[email-masked]> wrote:
> > about a year ago you posted a patch which allows to manage
> > network hotplug via udev (or busybox mdev), which is useful
> > for low-end embedded platforms that don't want to run ifplugd.
> >
> > http://article.gmane.org/gmane.linux.hotplug.devel/13386
> >
> > The patch still works with 2.6.32.  Can it get merged or
> > were there any issues with it?  It seems the discussion
> > just stopped and the patch was forgotten...
> 
> Can't, in some setups, these events happen at a rather high frequency?
> I heard of people running many hundreds of ppp interfaces on a single
> box acting as a DSL concentrator. They state to already have trouble
> handling the amount of uevents generated on such boxes just for the
> "add/remove" events of all the interfaces if something goes wrong with
> the network. If we add more for state transitions, such events would
> probably need to be rate-limited. In general, uevents/udev are not
> really suitable for high-frequency events, and if such behavior can be
> expected, we might better stick with the current netlink interface.

And then lets direct energy towards making the netlink interface simpler
for app writers.  Either by fixing up libnl to be dead-simple to use, or
some other mechanism.  Let's fix the *actual* problem (netlink is hard
to use from shell scripts) instead of creating more interfaces that work
around it.  Or maybe shellscripts are simply the wrong tool for this
job?

Dan