Re: [PATCH v2 net-next 01/26] rtnetlink: introduce generic XDP statistics

[David Ahern]

On 11/23/21 9:39 AM, Alexander Lobakin wrote:
> +static bool rtnl_get_xdp_stats_xdpxsk(struct sk_buff *skb, u32 ch,
> +				      const void *attr_data)
> +{
> +	const struct ifla_xdp_stats *xstats = attr_data;
> +
> +	xstats += ch;
> +
> +	if (nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_PACKETS, xstats->packets,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_BYTES, xstats->bytes,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_ERRORS, xstats->errors,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_ABORTED, xstats->aborted,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_DROP, xstats->drop,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_INVALID, xstats->invalid,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_PASS, xstats->pass,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_REDIRECT, xstats->redirect,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_REDIRECT_ERRORS,
> +			      xstats->redirect_errors,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_TX, xstats->tx,
> +			      IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_TX_ERRORS,
> +			      xstats->tx_errors, IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_XMIT_PACKETS,
> +			      xstats->xmit_packets, IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_XMIT_BYTES,
> +			      xstats->xmit_bytes, IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_XMIT_ERRORS,
> +			      xstats->xmit_errors, IFLA_XDP_XSTATS_UNSPEC) ||
> +	    nla_put_u64_64bit(skb, IFLA_XDP_XSTATS_XMIT_FULL,
> +			      xstats->xmit_full, IFLA_XDP_XSTATS_UNSPEC))
> +		return false;
> +
> +	return true;
> +}
> +

Another thought on this patch: with individual attributes you could save
some overhead by not sending 0 counters to userspace. e.g., define a
helper that does:

static inline int nla_put_u64_if_set(struct sk_buff *skb, int attrtype,
                                     u64 value, int padattr)
{
	if (value)
		return nla_put_u64_64bit(skb, attrtype, value, padattr);

	return 0;
}