Although there is a kfree_skb_reason() helper function that can be used to find the reason why this skb is dropped, 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 ip is increasing. Introduce netdev_core_stats_inc() for trace. Also, move dev_core_stats() and netdev_core_stats_alloc() to dev.c, as they are not called externally. Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Suggested-by: Alexander Lobakin <aleksander.lobakin@intel.com> --- v4: Introduce netdev_core_stats_inc() instead of export dev_core_stats_*_inc() v3: __cold should be added to the netdev_core_stats_alloc(). v2: use __cold instead of inline in dev_core_stats(). v1: https://lore.kernel.org/netdev/20230911082016.3694700-1-yajun.deng@linux.dev/ --- include/linux/netdevice.h | 21 ++++----------------- net/core/dev.c | 26 ++++++++++++++++++++++++-- 2 files changed, 28 insertions(+), 19 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index XXXXXXX..XXXXXXX 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -XXX,XX +XXX,XX @@ 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); -} +void netdev_core_stats_inc(struct net_device *dev, u32 offset); #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); \ + netdev_core_stats_inc(dev, \ + offsetof(struct net_device_core_stats, 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) +#undef DEV_CORE_STATS_INC static __always_inline int ____dev_forward_skb(struct net_device *dev, struct sk_buff *skb, diff --git a/net/core/dev.c b/net/core/dev.c index XXXXXXX..XXXXXXX 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -XXX,XX +XXX,XX @@ 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 __cold struct net_device_core_stats __percpu *netdev_core_stats_alloc( + struct net_device *dev) { struct net_device_core_stats __percpu *p; @@ -XXX,XX +XXX,XX @@ 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 *netdev_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); +} + +void netdev_core_stats_inc(struct net_device *dev, u32 offset) +{ + struct net_device_core_stats __percpu *p; + + p = netdev_core_stats(dev); + if (p) + this_cpu_inc(*(unsigned long *)((void *)p + offset)); +} +EXPORT_SYMBOL_GPL(netdev_core_stats_inc); /** * dev_get_stats - get network device statistics -- 2.25.1 Although there is a kfree_skb_reason() helper function that can be used to find the reason why this skb is dropped, 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 ip is increasing. Introduce netdev_core_stats_inc() for trace. Also, move dev_core_stats() and netdev_core_stats_alloc() to dev.c, as they are not called externally. Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Suggested-by: Alexander Lobakin <aleksander.lobakin@intel.com> --- v5: Access the per cpu pointer before reach the relevant offset. v4: Introduce netdev_core_stats_inc() instead of export dev_core_stats_*_inc() v3: __cold should be added to the netdev_core_stats_alloc(). v2: use __cold instead of inline in dev_core_stats(). v1: https://lore.kernel.org/netdev/20230911082016.3694700-1-yajun.deng@linux.dev/ --- include/linux/netdevice.h | 21 ++++----------------- net/core/dev.c | 26 ++++++++++++++++++++++++-- 2 files changed, 28 insertions(+), 19 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index XXXXXXX..XXXXXXX 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -XXX,XX +XXX,XX @@ 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); -} +void netdev_core_stats_inc(struct net_device *dev, u32 offset); #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); \ + netdev_core_stats_inc(dev, \ + offsetof(struct net_device_core_stats, 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) +#undef DEV_CORE_STATS_INC static __always_inline int ____dev_forward_skb(struct net_device *dev, struct sk_buff *skb, diff --git a/net/core/dev.c b/net/core/dev.c index XXXXXXX..XXXXXXX 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -XXX,XX +XXX,XX @@ 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 __cold struct net_device_core_stats __percpu *netdev_core_stats_alloc( + struct net_device *dev) { struct net_device_core_stats __percpu *p; @@ -XXX,XX +XXX,XX @@ 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 *netdev_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); +} + +void netdev_core_stats_inc(struct net_device *dev, u32 offset) +{ + struct net_device_core_stats __percpu *p; + + p = netdev_core_stats(dev); + if (p) + (*(unsigned long *)((void *)this_cpu_ptr(p) + offset))++; +} +EXPORT_SYMBOL_GPL(netdev_core_stats_inc); /** * dev_get_stats - get network device statistics -- 2.25.1