On Mon, 18 Nov 2019 14:55:23 -0800, Luigi Rizzo wrote:
> Drivers use different fields to report the number of channels, so take
> the maximum of all fields (rx, tx, other, combined) when determining the
> size of the xsk map. The current code used only 'combined' which was set
> to 0 in some drivers e.g. mlx4.
>
> Tested: compiled and run xdpsock -q 3 -r -S on mlx4
> Signed-off-by: Luigi Rizzo <lrizzo@xxxxxxxxxx>
thanks, this seems mostly correct
> diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
> index 74d84f36a5b24..8e12269428d08 100644
> --- a/tools/lib/bpf/xsk.c
> +++ b/tools/lib/bpf/xsk.c
> @@ -412,6 +412,11 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk)
> return 0;
> }
>
> +static inline int max_i(int a, int b)
> +{
> + return a > b ? a : b;
> +}
There's already a max in tools/lib/bpf/libbpf_internal.h, could you
possible just use that?
> static int xsk_get_max_queues(struct xsk_socket *xsk)
> {
> struct ethtool_channels channels = { .cmd = ETHTOOL_GCHANNELS };
> @@ -431,13 +436,18 @@ static int xsk_get_max_queues(struct xsk_socket *xsk)
> goto out;
> }
>
> - if (err || channels.max_combined == 0)
> + if (err) {
> /* If the device says it has no channels, then all traffic
> * is sent to a single stream, so max queues = 1.
> */
> ret = 1;
> - else
> - ret = channels.max_combined;
> + } else {
> + /* Take the max of rx, tx, other, combined. Drivers return
> + * the number of channels in different ways.
> + */
> + ret = max_i(max_i(channels.max_rx, channels.max_tx),
> + max_i(channels.max_other, channels.max_combined));
The continuation line should be aligned to the opening bracket.
I don't think we need to care about other, other is for non-traffic
interrupts.
> + }
>
> out:
> close(fd);
