[dpdk-dev] [PATCH] net/ixgbe: fix reconfiguration of rx queues

[Chas Williams]

On Mon, Jan 29, 2018 at 11:25 AM, Ananyev, Konstantin <
konstantin.ananyev at intel.com> wrote:

>
> > -----Original Message-----
> > From: Chas Williams [mailto:3chas3 at gmail.com]
> > Sent: Monday, January 29, 2018 3:21 PM
> > To: dev at dpdk.org
> > Cc: Lu, Wenzhuo <wenzhuo.lu at intel.com>; Ananyev, Konstantin <
> konstantin.ananyev at intel.com>; Charles (Chas) Williams
> > <chas3 at att.com>
> > Subject: [PATCH] net/ixgbe: fix reconfiguration of rx queues
> >
> > From: "Charles (Chas) Williams" <chas3 at att.com>
> >
> > .dev_configure() may be called again after RX queues have been setup.
> > This has the effect of clearing whatever setting the RX queues made for
> > rx_bulk_alloc_allowed or rx_vec_allowed.  Only reset this configuration
> > is there aren't any currently allocated queues.
> >
> > Fixes: 01fa1d6215fa ("ixgbe: unify Rx setup")
> >
> > Signed-off-by: Chas Williams <chas3 at att.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_ethdev.c | 18 ++++++++++++++++--
> >  1 file changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c b/drivers/net/ixgbe/ixgbe_
> ethdev.c
> > index 37eb668..b39249a 100644
> > --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> > +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> > @@ -2348,6 +2348,7 @@ ixgbe_dev_configure(struct rte_eth_dev *dev)
> >       struct ixgbe_adapter *adapter =
> >               (struct ixgbe_adapter *)dev->data->dev_private;
> >       int ret;
> > +     uint16_t i;
> >
> >       PMD_INIT_FUNC_TRACE();
> >       /* multipe queue mode checking */
> > @@ -2363,11 +2364,17 @@ ixgbe_dev_configure(struct rte_eth_dev *dev)
> >
> >       /*
> >        * Initialize to TRUE. If any of Rx queues doesn't meet the bulk
> > -      * allocation or vector Rx preconditions we will reset it.
> > +      * allocation or vector Rx preconditions we will reset it. We
> > +      * can only do this is there aren't any existing RX queues.
> >        */
> > +     for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > +             if (dev->data->rx_queues[i])
> > +                     goto out;
> > +     }
>
> I don't see why this is needed.
> It surely should be possible to reconfigure device with different
> number of queues.
> Konstantin
>

Yes, you can add new queues but you shouldn't reset the bulk and vec
settings
that have already been chosen by the previously allocated queues.  If those
queues
set rx_bulk_alloc_allowed to be false, then this is going to cause an issue
with queue
release later on.   This breaks:

rte_eth_dev_configure(..., 1, 1, ...);
rx_queue_setup(1)
   [rx_queue_setup decides that it can't support rx_bulk_alloc_allowed]
..

Later, you want to add some more queues,  you call

eth_eth_dev_configure(..., 2, 2, ...);
rx_queue_setup(2)
  [rx_queue_setup hopefully makes the same choice as rxqid = 1?]
...

Is one supposed to release all queues before calling
rte_eth_dev_configure()? If
that is true, it seems like the change_mtu examples I see are possibly
wrong.  As
suggested in kenrel_nic_interface.rst:


        ret = rte_eth_dev_configure(port_id, 1, 1, &conf);
        if (ret < 0) {
            RTE_LOG(ERR, APP, "Fail to reconfigure port %d\n", port_id);
            return ret;
        }

        /* Restart specific port */

        ret = rte_eth_dev_start(port_id);
        if (ret < 0) {
             RTE_LOG(ERR, APP, "Fail to restart port %d\n", port_id);
            return ret;
        }

This is will obviously reset the rx_bulk_alloc_allowed and not reallocated
the RX queues.


>
> >       adapter->rx_bulk_alloc_allowed = true;
> >       adapter->rx_vec_allowed = true;
> >
> > +out:
> >       return 0;
> >  }
> >
> > @@ -4959,6 +4966,7 @@ ixgbevf_dev_configure(struct rte_eth_dev *dev)
> >       struct rte_eth_conf *conf = &dev->data->dev_conf;
> >       struct ixgbe_adapter *adapter =
> >                       (struct ixgbe_adapter *)dev->data->dev_private;
> > +     uint16_t i;
> >
> >       PMD_INIT_LOG(DEBUG, "Configured Virtual Function port id: %d",
> >                    dev->data->port_id);
> > @@ -4981,11 +4989,17 @@ ixgbevf_dev_configure(struct rte_eth_dev *dev)
> >
> >       /*
> >        * Initialize to TRUE. If any of Rx queues doesn't meet the bulk
> > -      * allocation or vector Rx preconditions we will reset it.
> > +      * allocation or vector Rx preconditions we will reset it. We
> > +      * can only do this is there aren't any existing RX queues.
> >        */
> > +     for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > +             if (dev->data->rx_queues[i])
> > +                     goto out;
> > +     }
> >       adapter->rx_bulk_alloc_allowed = true;
> >       adapter->rx_vec_allowed = true;
> >
> > +out:
> >       return 0;
> >  }
> >
> > --
> > 2.9.5
>
>