Commit 5247dbf1 authored by Yajun Deng's avatar Yajun Deng Committed by David S. Miller
Browse files

net/core: Introduce netdev_core_stats_inc() 



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 the caller of
dev_core_stats_*_inc().

Also, add __code to netdev_core_stats_alloc(), as it's called with small
probability. And add noinline make sure netdev_core_stats_inc was never
inlined.

Signed-off-by: default avatarYajun Deng <yajun.deng@linux.dev>
Suggested-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0c2d3ff8

include/linux/netdevice.h

+4 −17
Original line number Diff line number Diff line
@@ -4002,32 +4002,19 @@ 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,

net/core/dev.c

+19 −2
Original line number Diff line number Diff line
@@ -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 +10511,23 @@ 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);



noinline void netdev_core_stats_inc(struct net_device *dev, u32 offset)

{

	/* This READ_ONCE() pairs with the write in netdev_core_stats_alloc() */

	struct net_device_core_stats __percpu *p = READ_ONCE(dev->core_stats);

	unsigned long __percpu *field;



	if (unlikely(!p)) {

		p = netdev_core_stats_alloc(dev);

		if (!p)

			return;

	}



	field = (__force unsigned long __percpu *)((__force void *)p + offset);

	this_cpu_inc(*field);

}

EXPORT_SYMBOL_GPL(netdev_core_stats_inc);



/**

 *	dev_get_stats	- get network device statistics