Re: [PATCH v1 net-next 1/5] drop_monitor: import netnamespace framework

On Wed, Jul 12, 2017 at 6:37 AM, Neil Horman [off-list ref] wrote:

On Wed, Jul 12, 2017 at 06:40:49PM +0800, martinbj2008@gmail.com wrote:

quoted

The dropwatch is a very useful tool to diagnose network problem,
which give us greate help.
Dropwatch could not work under container(net namespace).
It is a pitty, so let it support net ns.

Sorry, Im having a hard time wrapping my head around this.  Why exactly is it
that dropwatch won't work in a namespaced environment?  IIRC, the kfree
tracepoints are namespace agnostic, and so running dropwatch anywhere should
result in seeing drops in all namespaces.  I grant that perhaps it would be nice
to filter on a namespace, but it should all 'just work' for some definition of
the term, no?

Agreed.

And I doubt Martin's implementation which uses skb->sk to retrieve net
works for RX packets, since skb->sk is set very late (except with early demux)
on RX side but we can drop them at anytime...