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. 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() to dev.c, as they are not called
externally.
Signed-off-by: Yajun Deng <[email protected]>
---
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/[email protected]/
---
include/linux/netdevice.h | 32 +++++---------------------------
net/core/dev.c | 32 ++++++++++++++++++++++++++++++--
2 files changed, 35 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..98592e4c1df0 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 __cold struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device *dev)
{
struct net_device_core_stats __percpu *p;
@@ -10488,7 +10488,35 @@ 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)
+{
+ /* 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
From: Yajun Deng <[email protected]>
Date: Thu, 14 Sep 2023 10:37:18 +0800
> 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. 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() to dev.c, as they are not called
> externally.
I'd like to hear some arguments against having them static inlines + one
external that I proposed earlier.
>
> Signed-off-by: Yajun Deng <[email protected]>
> ---
> 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/[email protected]/
...as it's not at least mentioned here in the changelog.
[...]
> diff --git a/net/core/dev.c b/net/core/dev.c
> index ccff2b6ef958..98592e4c1df0 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 __cold struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device *dev)
This is way over 79/80 chars, break the line before "netdev_".
> {
> struct net_device_core_stats __percpu *p;
>
> @@ -10488,7 +10488,35 @@ 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)
Same for the line length.
Also notice that now some of the functions you touch have "dev_" prefix,
others have "netdev_", I'd probably take a look into unifying this.
(note for the maintainers that it would be probably better to leave
explicit "inline" here, but no bloat-o-meter was provided by the
author, so I can't say anything for sure)
> +{
> + /* 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);
> +}
[...]
Thanks,
Olek
On 2023/9/14 23:22, Alexander Lobakin wrote:
> From: Yajun Deng <[email protected]>
> Date: Thu, 14 Sep 2023 10:37:18 +0800
>
>> 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. 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() to dev.c, as they are not called
>> externally.
> I'd like to hear some arguments against having them static inlines + one
> external that I proposed earlier.
I'd like to hear suggestions from the maintainers. If the maintainers
have no objections, I'd like to
use your approach.
>> Signed-off-by: Yajun Deng <[email protected]>
>> ---
>> 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/[email protected]/
> ...as it's not at least mentioned here in the changelog.
>
> [...]
>
>> diff --git a/net/core/dev.c b/net/core/dev.c
>> index ccff2b6ef958..98592e4c1df0 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 __cold struct net_device_core_stats __percpu *netdev_core_stats_alloc(struct net_device *dev)
> This is way over 79/80 chars, break the line before "netdev_".
Okay.
>
>> {
>> struct net_device_core_stats __percpu *p;
>>
>> @@ -10488,7 +10488,35 @@ 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)
> Same for the line length.
> Also notice that now some of the functions you touch have "dev_" prefix,
> others have "netdev_", I'd probably take a look into unifying this.
Okay, I'll unify with the "netdev_" prefix.
> (note for the maintainers that it would be probably better to leave
> explicit "inline" here, but no bloat-o-meter was provided by the
> author, so I can't say anything for sure)
>
>> +{
>> + /* 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);
>> +}
> [...]
>
> Thanks,
> Olek