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Subject: Re: [PATCH net-next] net: core: Expose number of link up/down
 transitions
To: Florian Fainelli <f.fainelli@gmail.com>, netdev@vger.kernel.org
Cc: edumazet@google.com, andrew@lunn.ch, cphealy@gmail.com,
        David Decotigny <decot@googlers.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>, Jiri Pirko <jiri@resnulli.us>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Nikolay Aleksandrov <nikolay@cumulusnetworks.com>,
        Alexei Starovoitov <ast@fb.com>,
        Roopa Prabhu <roopa@cumulusnetworks.com>,
        Mahesh Bandewar <maheshb@google.com>,
        Vlad Yasevich <vyasevich@gmail.com>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Jonas Bonn <jonas@southpole.se>,
        stephen hemminger <stephen@networkplumber.org>,
        Hans Liljestrand <ishkamiel@gmail.com>,
        "Reshetova, Elena" <elena.reshetova@intel.com>,
        Kirill Tkhai <ktkhai@virtuozzo.com>, Andrey Vagin <avagin@openvz.org>,
        Florian Westphal <fw@strlen.de>, Xin Long <lucien.xin@gmail.com>,
        Matthias Schiffer <mschiffer@universe-factory.net>,
        Jiri Benc <jbenc@redhat.com>, open list <linux-kernel@vger.kernel.org>
References: <20180117230704.21949-1-f.fainelli@gmail.com>
From: David Ahern <dsahern@gmail.com>
Message-ID: <d4770873-9ce0-a102-520d-8e78b5d0b82a@gmail.com>
Date: Wed, 17 Jan 2018 16:28:49 -0800
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On 1/17/18 3:06 PM, Florian Fainelli wrote:
> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
> index 7bf8b85ade16..9f732c3dc2ce 100644
> --- a/net/core/net-sysfs.c
> +++ b/net/core/net-sysfs.c
> @@ -295,10 +295,29 @@ static ssize_t carrier_changes_show(struct device *dev,
>  	struct net_device *netdev = to_net_dev(dev);
>  
>  	return sprintf(buf, fmt_dec,
> -		       atomic_read(&netdev->carrier_changes));
> +		       atomic_read(&netdev->count_link_up) +
> +		       atomic_read(&netdev->count_link_down));
>  }
>  static DEVICE_ATTR_RO(carrier_changes);
>  
> +static ssize_t count_link_up_show(struct device *dev,
> +				  struct device_attribute *attr, char *buf)
> +{
> +	struct net_device *netdev = to_net_dev(dev);
> +
> +	return sprintf(buf, fmt_dec, atomic_read(&netdev->count_link_up));
> +}
> +static DEVICE_ATTR_RO(count_link_up);
> +
> +static ssize_t count_link_down_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	struct net_device *netdev = to_net_dev(dev);
> +
> +	return sprintf(buf, fmt_dec, atomic_read(&netdev->count_link_down));
> +}
> +static DEVICE_ATTR_RO(count_link_down);
> +
>  /* read-write attributes */
>  
>  static int change_mtu(struct net_device *dev, unsigned long new_mtu)
> @@ -547,6 +566,8 @@ static struct attribute *net_class_attrs[] __ro_after_init = {
>  	&dev_attr_phys_port_name.attr,
>  	&dev_attr_phys_switch_id.attr,
>  	&dev_attr_proto_down.attr,
> +	&dev_attr_count_link_up.attr,
> +	&dev_attr_count_link_down.attr,
>  	NULL,
>  };
>  ATTRIBUTE_GROUPS(net_class);

Personally, I do not like adding any more sysfs files. As discussed in
the past sysfs is a huge contributor to the overhead of netdevs.