Subject: Re: [PATCH net-next V2 1/3] tun: abstract flow steering logic

From: "Michael S. Tsirkin" <[email-masked]>
Date: Thu, 2 Nov 2017 05:45:15 +0200

On Thu, Nov 02, 2017 at 11:43:48AM +0800, Jason Wang wrote:
> 
> 
> On 2017年11月02日 09:11, Willem de Bruijn wrote:
> > On Tue, Oct 31, 2017 at 7:32 PM, Jason Wang <[email-masked]> wrote:
> > > tun now use flow caches based automatic queue steering method. This
> > > may not suffice all user cases. To extend it to be able to use more
> > > flow steering policy, this patch abstracts flow steering logic into
> > > tun_steering_ops, then we can declare and use different methods in
> > > the future.
> > > Signed-off-by: Jason Wang <[email-masked]>
> > > ---
> > >   drivers/net/tun.c | 85 +++++++++++++++++++++++++++++++++++++++++--------------
> > >   1 file changed, 63 insertions(+), 22 deletions(-)
> > > 
> > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> > > index ea29da9..bff6259 100644
> > The previous RFC enabled support for multiple pluggable steering
> > policies. But as all can be implemented in BPF and we only plan to
> > support an eBPF policy besides the legacy one, this patch is no longer
> > needed. We can save a few indirect function calls.
> 
> But we should at least support two kinds of steering policy, so this is
> still needed?
> 
> And I'm not quite sure we can implement all kinds of policies through BPF
> e.g RSS or we may want to offload the queue selection to underlayer switch
> or nic .
> 
> Thanks

I think a simple if condition is preferable for now, too. Let's wait
until we get some 3/4 of these.

-- 
MST