netdev - Re: [PATCH] net: add net namespace inode for all net

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Date:   Wed, 10 Mar 2021 17:33:29 +0800
From:   Tony Lu <tonylu@...ux.alibaba.com>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     davem@...emloft.net, rostedt@...dmis.org, mingo@...hat.com,
        Lorenz Bauer <lmb@...udflare.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: add net namespace inode for all net_dev events

On Tue, Mar 09, 2021 at 09:12:45PM +0100, Eric Dumazet wrote:
> 
> 
> On 3/9/21 5:43 AM, Tony Lu wrote:
> > There are lots of net namespaces on the host runs containers like k8s.
> > It is very common to see the same interface names among different net
> > namespaces, such as eth0. It is not possible to distinguish them without
> > net namespace inode.
> > 
> > This adds net namespace inode for all net_dev events, help us
> > distinguish between different net devices.
> > 
> > Output:
> >   <idle>-0       [006] ..s.   133.306989: net_dev_xmit: net_inum=4026531992 dev=eth0 skbaddr=0000000011a87c68 len=54 rc=0
> > 
> > Signed-off-by: Tony Lu <tonylu@...ux.alibaba.com>
> > ---
> >
> 
> There was a proposal from Lorenz to use netns cookies (SO_NETNS_COOKIE) instead.
> 
> They have a guarantee of being not reused.
> 
> After 3d368ab87cf6681f9 ("net: initialize net->net_cookie at netns setup")
> net->net_cookie is directly available.

It looks better to identify ns with net_cookie rather than inode, and
get the value with NS_GET_COOKIE. I will switch net_inum to net_cookie
in the next patch.


Cheers,
Tony Lu

>