On Thu, 9 Aug 2018 19:27:55 +0800 Jisheng Zhang wrote:
> Hi,
>
> On Thu, 9 Aug 2018 12:40:41 +0800 Jisheng Zhang wrote:
>
> > + more people
> >
> > On Wed, 8 Aug 2018 17:27:05 +0200 Marek Behún wrote:
> >
> > > For some reason on Armada 3720 boards (EspressoBin and Turris Mox) the
> > > networking driver behaves weirdly when using napi_gro_receive.
> > >
> > > For example downloading a big file from a local network (low ping) is
> > > fast, but when downloading from a remote server (higher ping), the
> > > download speed is at first high but drops rapidly to almost nothing or
> > > absolutely nothing.
> >
> > We also met this issue on some berlin platforms. I tried to fix the bug,
> > but no clue so far.
> >
> > >
> > > This is fixed when using netif_receive_skb instead of napi_gro_receive.
> > >
> >
> > This is a workaround. The good news is this workaround also fixes the issue
> > we saw on berlin.
> >
> > >
> > > Signed-off-by: Marek Behun <[email protected]>
> > > Cc: Russell King - ARM Linux <[email protected]>
> > > Cc: [email protected]
> > >
> > > diff --git a/drivers/net/ethernet/marvell/mvneta.c
> > > b/drivers/net/ethernet/marvell/mvneta.c
> > > index 0ad2f3f7da85..27f3017d94c5 100644
> > > --- a/drivers/net/ethernet/marvell/mvneta.c
> > > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > > @@ -1959,7 +1959,10 @@ static int mvneta_rx_swbm(struct mvneta_port *pp,
> > > int rx_todo,
> > >
> > > skb->protocol = eth_type_trans(skb, dev);
> > > mvneta_rx_csum(pp, rx_status, skb);
> > > - napi_gro_receive(&port->napi, skb);
> > > + if (pp->neta_armada3700)
> > > + netif_receive_skb(skb);
> > > + else
> > > + napi_gro_receive(&port->napi, skb);
>
> I think I found the root cause, if neta_armada3700 is true, the port got from
> this_cpu_ptr(pp->ports) is invalid, this is bug... I'll cook a patch for this
correct it as:
the port's(port is got from this_cpu_ptr(pp->ports) napi is invalid.
Patch is sent out. Could you please try?
Per my test, it solves the issue we saw on berlin.
>
> Thanks
>
> > >
> > > rcvd_pkts++;
> > > rcvd_bytes += rx_bytes;
> > > @@ -2001,7 +2004,10 @@ static int mvneta_rx_swbm(struct mvneta_port *pp,
> > > int rx_todo,
> > >
> > > mvneta_rx_csum(pp, rx_status, skb);
> > >
> > > - napi_gro_receive(&port->napi, skb);
> > > + if (pp->neta_armada3700)
> > > + netif_receive_skb(skb);
> > > + else
> > > + napi_gro_receive(&port->napi, skb);
> > > }
> > >
> > > if (rcvd_pkts) {
> >
>
