Messages in this thread | | | Subject | Re: [PATCH net-next v5] net/core: Introduce netdev_core_stats_inc() for trace | From | Paolo Abeni <> | Date | Thu, 28 Sep 2023 10:23:50 +0200 |
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On Tue, 2023-09-19 at 21:55 +0800, Yajun Deng wrote: > 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 db3d8429d50d..4c258d44c7d2 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -4001,32 +4001,19 @@ 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 606a366cc209..4bc0161bc0d6 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -10497,7 +10497,8 @@ 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; > > @@ -10510,7 +10511,28 @@ 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)
I'm sorry for the delayed feedback - conference and traveling in the way.
It looks like the 'inline' keyword above is a left-over of a previous revision? The compiler should generate the same code even without it, right? If so, it should be better drop it.
Cheers,
Paolo
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