Re: [PATCH 3/3] net: core: add IFLA_STATS64 support

[Eric Dumazet <eric.dumazet@gmail.com>]

Le jeudi 11 mars 2010 à 20:57 +0100, Jan Engelhardt a écrit :
> `ip -s link` shows interface counters truncated to 32 bit. This is
> because interface statistics are transported only in 32-bit quantity
> to userspace. This commit adds a new IFLA_STATS64 attribute that
> exports them in full 64 bit.
> 
> References: http://lkml.indiana.edu/hypermail/linux/kernel/0307.3/0215.html

oh oh, back to  2003 :)

> Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
> ---
>  
>  static inline int rtnl_vfinfo_size(const struct net_device *dev)
>  {
> @@ -698,6 +730,14 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
>  	stats = dev_get_stats(dev);

OK, stats is up2date with device stats

>  	copy_rtnl_link_stats(nla_data(attr), stats);
>  
> +	attr = nla_reserve(skb, IFLA_STATS64,
> +			sizeof(struct rtnl_link_stats64));
> +	if (attr == NULL)
> +		goto nla_put_failure;
> +
> +	stats = dev_get_stats(dev);

Why calling dev_get_stats(dev) a second time ?
Its can be pretty expensive on some devices.

> +	copy_rtnl_link_stats64(nla_data(attr), stats);
> +
>  	if (dev->netdev_ops->ndo_get_vf_config && dev->dev.parent) {
>  		int i;
>  		struct ifla_vf_info ivi;
> --