> -----Original Message-----
> From: Tom Herbert [mailto:[email protected]]
> Sent: Monday, September 12, 2016 4:23 PM
> To: Liang, Kan <[email protected]>
> Cc: David S. Miller <[email protected]>; LKML <linux-
> [email protected]>; Linux Kernel Network Developers
> <[email protected]>; Kirsher, Jeffrey T <[email protected]>;
> Ingo Molnar <[email protected]>; [email protected]; Alexey Kuznetsov
> <[email protected]>; James Morris <[email protected]>; Hideaki
> YOSHIFUJI <[email protected]>; Patrick McHardy <[email protected]>;
> [email protected]; Kees Cook <[email protected]>;
> [email protected]; [email protected]; John Stultz
> <[email protected]>; Alexander Duyck <[email protected]>; Ben
> Hutchings <[email protected]>; David Decotigny <[email protected]>;
> Florian Westphal <[email protected]>; Alexander Duyck
> <[email protected]>; Daniel Borkmann <[email protected]>;
> [email protected]; Cong Wang <[email protected]>; Hannes
> Frederic Sowa <[email protected]>; Stephen Hemminger
> <[email protected]>; Alexei Starovoitov
> <[email protected]>; Brandeburg, Jesse
> <[email protected]>; Andi Kleen <[email protected]>
> Subject: Re: [RFC V3 PATCH 18/26] net/netpolicy: set tx queues according to
> policy
> 
> On Mon, Sep 12, 2016 at 7:55 AM,  <[email protected]> wrote:
> > From: Kan Liang <[email protected]>
> >
> > When the device tries to transmit a packet, netdev_pick_tx is called
> > to find the available tx queues. If the net policy is applied, it
> > picks up the assigned tx queue from net policy subsystem, and redirect
> > the traffic to the assigned queue.
> >
> > Signed-off-by: Kan Liang <[email protected]>
> > ---
> >  include/net/sock.h |  9 +++++++++
> >  net/core/dev.c     | 20 ++++++++++++++++++--
> >  2 files changed, 27 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/net/sock.h b/include/net/sock.h index
> > e1e9e3d..ca97f35 100644
> > --- a/include/net/sock.h
> > +++ b/include/net/sock.h
> > @@ -2280,4 +2280,13 @@ extern int sysctl_optmem_max;  extern __u32
> > sysctl_wmem_default;  extern __u32 sysctl_rmem_default;
> >
> > +/* Return netpolicy instance information from socket. */ static
> > +inline struct netpolicy_instance *netpolicy_find_instance(struct sock
> > +*sk) { #ifdef CONFIG_NETPOLICY
> > +       if (is_net_policy_valid(sk->sk_netpolicy.policy))
> > +               return &sk->sk_netpolicy; #endif
> > +       return NULL;
> > +}
> >  #endif /* _SOCK_H */
> > diff --git a/net/core/dev.c b/net/core/dev.c index 34b5322..b9a8044
> > 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -3266,6 +3266,7 @@ struct netdev_queue *netdev_pick_tx(struct
> net_device *dev,
> >                                     struct sk_buff *skb,
> >                                     void *accel_priv)  {
> > +       struct sock *sk = skb->sk;
> >         int queue_index = 0;
> >
> >  #ifdef CONFIG_XPS
> > @@ -3280,8 +3281,23 @@ struct netdev_queue *netdev_pick_tx(struct
> net_device *dev,
> >                 if (ops->ndo_select_queue)
> >                         queue_index = ops->ndo_select_queue(dev, skb, 
> > accel_priv,
> >                                                             
> > __netdev_pick_tx);
> > -               else
> > -                       queue_index = __netdev_pick_tx(dev, skb);
> > +               else {
> > +#ifdef CONFIG_NETPOLICY
> > +                       struct netpolicy_instance *instance;
> > +
> > +                       queue_index = -1;
> > +                       if (dev->netpolicy && sk) {
> > +                               instance = netpolicy_find_instance(sk);
> > +                               if (instance) {
> > +                                       if (!instance->dev)
> > +                                               instance->dev = dev;
> > +                                       queue_index = 
> > netpolicy_pick_queue(instance, false);
> > +                               }
> > +                       }
> > +                       if (queue_index < 0) #endif
> 
> I doubt this produces the intended effect. Several drivers use
> ndo_select_queue (such as mlx4) where there might do something special
> for a few packets but end up called the default handler which
> __netdev_pick_tx for most packets. So in such cases the netpolicy path would
> be routinely bypassed. Maybe this code should be in __netdev_pick_tx.

I will move the code to __netdev_pick_tx in next version.

Thanks,
Kan

> 
> Tom
> 
> > +                               queue_index = __netdev_pick_tx(dev, skb);
> > +               }
> >
> >                 if (!accel_priv)
> >                         queue_index = netdev_cap_txqueue(dev,
> > queue_index);
> > --
> > 2.5.5
> >

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