[Lxc-users] Bad checksums and lost packets with macvlan on dummy
Eric Dumazet
eric.dumazet at gmail.com
Sun Feb 27 19:50:36 UTC 2011
Le dimanche 27 février 2011 à 16:14 +0100, Daniel Lezcano a écrit :
> On 02/23/2011 06:13 PM, Andrian Nord wrote:
> > On Mon, Feb 21, 2011 at 05:07:31PM +0100, Daniel Lezcano wrote:
> >> I Cc'ed the netdev mailing list and Patrick in case my analysis is wrong
> >> or incomplete.
> > I'm confirming, that this happens only when macvlan's are onto dummy net
> > device. In case of some physical interface under macvlan there is no lost
> > packages and no broken checksums.
>
> I did some tests with a 2.6.35 kernel version and it seems the checksum
> errors do not appear.
> I noticed there are some changes in the dummy setup function:
>
> dev->features |= NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_TSO;
> dev->features |= NETIF_F_NO_CSUM | NETIF_F_HIGHDMA | NETIF_F_LLTX;
>
>
> May be that was introduced by commit:
>
> commit 6d81f41c58c69ddde497e9e640ba5805aa26e78c
> Author: Eric Dumazet <eric.dumazet at gmail.com>
> Date: Mon Sep 27 20:50:33 2010 +0000
>
> dummy: percpu stats and lockless xmit
>
> Converts dummy network device driver to :
>
> - percpu stats
>
> - 64bit stats
>
> - lockless xmit (NETIF_F_LLTX)
>
> - performance features added (NETIF_F_SG | NETIF_F_FRAGLIST |
> NETIF_F_TSO | NETIF_F_NO_CSUM | NETIF_F_HIGHDMA)
>
> Signed-off-by: Eric Dumazet <eric.dumazet at gmail.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
>
>
> Eric,
>
> Andrian is observing, with a couple of macvlan (in bridge mode) on top
> of a dummy interface, a lot of checksums error and packets drop.
> Each macvlan is in a different network namespace and the dummy interface
> is in the init_net.
>
> Any ideas ?
Not sure I understand... I thought dummy was dropping all frames
anyway ?
static netdev_tx_t dummy_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats);
u64_stats_update_begin(&dstats->syncp);
dstats->tx_packets++;
dstats->tx_bytes += skb->len;
u64_stats_update_end(&dstats->syncp);
dev_kfree_skb(skb);
return NETDEV_TX_OK;
}
Maybe you could describe the setup ?
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