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Date:   Wed, 13 Sep 2023 10:20:32 +0800
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Subject: Re: [PATCH] net/core: Export dev_core_stats_rx_dropped_inc sets
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To:     Eric Dumazet <edumazet@google.com>,
        Alexander Lobakin <aleksander.lobakin@intel.com>
Cc:     davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
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From:   Yajun Deng <yajun.deng@linux.dev>
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On 2023/9/13 02:05, Eric Dumazet wrote:
> On Tue, Sep 12, 2023 at 8:03 PM Eric Dumazet <edumazet@google.com> wrote:
>
>> Sure, this was what was suggested (perhaps not _very_ precisely, but
>> the general idea was pretty clear).
>> v2 seems ok, right ?
>>
>> It seems we are all on the same page.
>>
>> +static __cold 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)
> Oh well, I just read the patch, and it seems wrong indeed.
>
> netdev_core_stats_alloc() is the one that can be cold.

Okay, I would add __cold to netdev_core_stats_alloc() in v3.

Olek suggest that define a new dev_core_stats_inc() function.

I hope to see the suggestion in another reply.