On Wed, Jun 27, 2018 at 4:20 AM, Jesper Dangaard Brouer
<bro...@redhat.com> wrote:
> On Tue, 26 Jun 2018 17:09:01 -0700
> Song Liu <liu.song....@gmail.com> wrote:
>
>> On Mon, Jun 25, 2018 at 7:27 AM, Jesper Dangaard Brouer
>> <bro...@redhat.com> wrote:
>> > XDP_TX requires also changing the MAC-addrs, else some hardware
>> > may drop the TX packet before reaching the wire. This was
>> > observed with driver mlx5.
>> >
>> > If xdp_rxq_info select --action XDP_TX the swapmac functionality
>> > is activated. It is also possible to manually enable via cmdline
>> > option --swapmac. This is practical if wanting to measure the
>> > overhead of writing/updating payload for other action types.
>> >
>> > Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
>> > Signed-off-by: Toke Høiland-Jørgensen <t...@toke.dk>
>> > ---
> [...]
>> >
>> > diff --git a/samples/bpf/xdp_rxq_info_kern.c
>> > b/samples/bpf/xdp_rxq_info_kern.c
>> > index 61af6210df2f..222a83eed1cb 100644
>> > --- a/samples/bpf/xdp_rxq_info_kern.c
>> > +++ b/samples/bpf/xdp_rxq_info_kern.c
>> > @@ -21,6 +21,7 @@ struct config {
>> > enum cfg_options_flags {
>> > NO_TOUCH = 0x0U,
>> > READ_MEM = 0x1U,
>> > + SWAP_MAC = 0x2U,
>> > };
> [...]
>> > @@ -98,7 +116,7 @@ int xdp_prognum0(struct xdp_md *ctx)
>> > rxq_rec->issue++;
>> >
>> > /* Default: Don't touch packet data, only count packets */
>> > - if (unlikely(config->options & READ_MEM)) {
>> > + if (unlikely(config->options & (READ_MEM|SWAP_MAC))) {
>> > struct ethhdr *eth = data;
>> >
>> > if (eth + 1 > data_end)
> [...]
>
>> > diff --git a/samples/bpf/xdp_rxq_info_user.c
>> > b/samples/bpf/xdp_rxq_info_user.c
>> > index 435485d4f49e..248a7eab9531 100644
> [...]
>> > @@ -119,6 +121,8 @@ static char* options2str(enum cfg_options_flags flag)
>> > {
>> > if (flag == NO_TOUCH)
>> > return "no_touch";
>> > + if (flag & SWAP_MAC)
>> > + return "swapmac";
>> > if (flag & READ_MEM)
>> > return "read";
>>
>> I guess SWAP_MAC also reads the memory, so it "includes" READ_MEM?
>
> True (see _kern side)
>
>> It is OK for now. We may need to refactor this part when adding other
>> flags in the future.
>
> Sure, do remember that this is only a 'sample' program.
Agreed.
Acked-by: Song Liu <songliubrav...@fb.com>
