linux-kernel - Re: [PATCH net-next v7] net/core: Introduce netdev_core_stats

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Message-ID: <508b33f7-3dc0-4536-21f6-4a5e7ade2b5c@linux.dev>
Date:   Mon, 9 Oct 2023 16:13:54 +0800
From:   Yajun Deng <yajun.deng@...ux.dev>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     rostedt@...dmis.org, mhiramat@...nel.org, dennis@...nel.org,
        tj@...nel.org, cl@...ux.com, mark.rutland@....com,
        davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Alexander Lobakin <aleksander.lobakin@...el.com>,
        linux-trace-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH net-next v7] net/core: Introduce netdev_core_stats_inc()


On 2023/10/9 15:53, Eric Dumazet wrote:
> On Mon, Oct 9, 2023 at 5:07 AM Yajun Deng <yajun.deng@...ux.dev> wrote:
>
>> 'this_cpu_read + this_cpu_write' and 'pr_info + this_cpu_inc' will make
>> the trace work well.
>>
>> They all have 'pop' instructions in them. This may be the key to making
>> the trace work well.
>>
>> Hi all,
>>
>> I need your help on percpu and ftrace.
>>
> I do not think you made sure netdev_core_stats_inc() was never inlined.
>
> Adding more code in it is simply changing how the compiler decides to
> inline or not.


Yes, you are right. It needs to add the 'noinline' prefix. The 
disassembly code will have 'pop'

instruction.

Thanks.