[net-next,v4] net/core: Introduce netdev_core_stats_inc() for trace
Commit Message
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(-)
Comments
On Mon, 2023-09-18 at 10:40 +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>
> ---
> 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 0896aaa91dd7..cddd4873b5b0 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -3980,32 +3980,19 @@ 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 ccff2b6ef958..f4cccdf05450 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -10475,7 +10475,8 @@ 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;
>
> @@ -10488,7 +10489,28 @@ 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)
> +{
> + /* 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));
The above is causing a lot of compile warning, as it's discarding the
(required) __percpu annotation.
You need to first access the per cpu pointer and then reach for the
relevant offset.
Cheers,
Paolo
On 2023/9/19 17:10, Paolo Abeni wrote:
> On Mon, 2023-09-18 at 10:40 +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>
>> ---
>> 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 0896aaa91dd7..cddd4873b5b0 100644
>> --- a/include/linux/netdevice.h
>> +++ b/include/linux/netdevice.h
>> @@ -3980,32 +3980,19 @@ 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 ccff2b6ef958..f4cccdf05450 100644
>> --- a/net/core/dev.c
>> +++ b/net/core/dev.c
>> @@ -10475,7 +10475,8 @@ 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;
>>
>> @@ -10488,7 +10489,28 @@ 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)
>> +{
>> + /* 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));
> The above is causing a lot of compile warning, as it's discarding the
> (required) __percpu annotation.
>
> You need to first access the per cpu pointer and then reach for the
> relevant offset.
Indeed, thanks.
>
> Cheers,
>
> Paolo
>
@@ -3980,32 +3980,19 @@ 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,
@@ -10475,7 +10475,8 @@ 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;
@@ -10488,7 +10489,28 @@ 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)
+{
+ /* 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