Re: [PATCH net-next] fq_codel: report congestion notification at enqueue time

David Miller
2012-06-29T08:04:29Z

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 29 Jun 2012 07:50:08 +0200

> Hmm, problem is the sender thinks the packet was queued for
> transmission.
>
> ret = macvlan_queue_xmit(skb, dev);
> if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
> struct macvlan_pcpu_stats *pcpu_stats;
>
> pcpu_stats = this_cpu_ptr(vlan->pcpu_stats);
> u64_stats_update_begin(&pcpu_stats->syncp);
> pcpu_stats->tx_packets++;
> pcpu_stats->tx_bytes += len;
> u64_stats_update_end(&pcpu_stats->syncp);
> } else {
> this_cpu_inc(vlan->pcpu_stats->tx_dropped);
> }

Ok, that is the meaning this has taken on. Same test exists in
vlan_dev.c and this test used to be present also in the ipip.h macros
some time ago.

Nobody really does anything special with this value, except to
translate it to a zero 0 when propagating back to sockets.

The only thing it guards is the selection of which statistic to
increment.

For all practical purposes it is treated as NET_XMIT_SUCCESS except in
one location, pktgen, where it causes the errors counter to increment.

Looking this over, I'd say we should just get rid of it.