On Mon, Sep 11, 2023 at 10:20 AM Yajun Deng <[email protected]> wrote:
>
> Although there is a kfree_skb_reason() helper function that can be used
> to find the reason for dropped packets, but most callers didn't increase
> one of rx_dropped, tx_dropped, rx_nohandler and rx_otherhost_dropped.
>
> For the users, people are more concerned about why the dropped in ifconfig
> is increasing. So we can export dev_core_stats_rx_dropped_inc sets,
> which users would trace them know why rx_dropped is increasing.
>
> Export dev_core_stats_{rx_dropped, tx_dropped, rx_nohandler,
> rx_otherhost_dropped}_inc for trace. Also, move dev_core_stats()
> and netdev_core_stats_alloc() in dev.c, because they are not called
> externally.
>
> Signed-off-by: Yajun Deng <[email protected]>
Okay, but it seems you forgot to say which tree was targeted by this patch.
Documentation/process/maintainer-netdev.rst
I would guess net-next, but patch authors are supposed to be explicit.
> ---
> include/linux/netdevice.h | 32 +++++---------------------------
> net/core/dev.c | 30 ++++++++++++++++++++++++++++--
> 2 files changed, 33 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 0896aaa91dd7..879b01c85ba4 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -3954,6 +3954,11 @@ int dev_forward_skb_nomtu(struct net_device *dev, struct sk_buff *skb);
> bool is_skb_forwardable(const struct net_device *dev,
> const struct sk_buff *skb);
>
> +void dev_core_stats_rx_dropped_inc(struct net_device *dev);
> +void dev_core_stats_tx_dropped_inc(struct net_device *dev);
> +void dev_core_stats_rx_nohandler_inc(struct net_device *dev);
> +void dev_core_stats_rx_otherhost_dropped_inc(struct net_device *dev);
> +
> static __always_inline bool __is_skb_forwardable(const struct net_device *dev,
> const struct sk_buff *skb,
> const bool check_mtu)
> @@ -3980,33 +3985,6 @@ static __always_inline bool __is_skb_forwardable(const struct net_device *dev,
> return false;
> }
>
> -struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device *dev);
> -
> -static inline struct net_device_core_stats __percpu *dev_core_stats(struct net_device *dev)
> -{
> - /* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */
> - struct net_device_core_stats __percpu *p = READ_ONCE(dev->core_stats);
> -
> - if (likely(p))
> - return p;
> -
> - return netdev_core_stats_alloc(dev);
> -}
> -
> -#define DEV_CORE_STATS_INC(FIELD) \
> -static inline void dev_core_stats_##FIELD##_inc(struct net_device *dev) \
> -{ \
> - struct net_device_core_stats __percpu *p; \
> - \
> - p = dev_core_stats(dev); \
> - if (p) \
> - this_cpu_inc(p->FIELD); \
> -}
> -DEV_CORE_STATS_INC(rx_dropped)
> -DEV_CORE_STATS_INC(tx_dropped)
> -DEV_CORE_STATS_INC(rx_nohandler)
> -DEV_CORE_STATS_INC(rx_otherhost_dropped)
> -
> static __always_inline int ____dev_forward_skb(struct net_device *dev,
> struct sk_buff *skb,
> const bool check_mtu)
> diff --git a/net/core/dev.c b/net/core/dev.c
> index ccff2b6ef958..32ba730405b4 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -10475,7 +10475,7 @@ void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
> }
> EXPORT_SYMBOL(netdev_stats_to_stats64);
>
> -struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device *dev)
> +static struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device *dev)
> {
> struct net_device_core_stats __percpu *p;
>
> @@ -10488,7 +10488,33 @@ struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device
> /* This READ_ONCE() pairs with the cmpxchg() above */
> return READ_ONCE(dev->core_stats);
> }
> -EXPORT_SYMBOL(netdev_core_stats_alloc);
> +
> +static inline struct net_device_core_stats __percpu *dev_core_stats(struct net_device *dev)
Please remove this inline attritbute. Consider using __cold instead.
> +{
> + /* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */
> + struct net_device_core_stats __percpu *p = READ_ONCE(dev->core_stats);
> +
> + if (likely(p))
> + return p;
> +
> + return netdev_core_stats_alloc(dev);
> +}
> +
> +#define DEV_CORE_STATS_INC(FIELD) \
> +void dev_core_stats_##FIELD##_inc(struct net_device *dev) \
> +{ \
> + struct net_device_core_stats __percpu *p; \
> + \
> + p = dev_core_stats(dev); \
> + if (p) \
> + this_cpu_inc(p->FIELD); \
> +} \
> +EXPORT_SYMBOL(dev_core_stats_##FIELD##_inc)
> +
> +DEV_CORE_STATS_INC(rx_dropped);
> +DEV_CORE_STATS_INC(tx_dropped);
> +DEV_CORE_STATS_INC(rx_nohandler);
> +DEV_CORE_STATS_INC(rx_otherhost_dropped);
#undef DEV_CORE_STATS_INC
>
> /**
> * dev_get_stats - get network device statistics
> --
> 2.25.1
>