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From:   Eric Dumazet <edumazet@google.com>
Date:   Mon, 9 Oct 2023 09:53:51 +0200
Message-ID: <CANn89iJCTgWTu0mzwj-8_-HiWm4uErY=VASDHoYaod9Nq-ayPA@mail.gmail.com>
Subject: Re: [PATCH net-next v7] net/core: Introduce netdev_core_stats_inc()
To:     Yajun Deng <yajun.deng@linux.dev>
Cc:     rostedt@goodmis.org, mhiramat@kernel.org, dennis@kernel.org,
        tj@kernel.org, cl@linux.com, mark.rutland@arm.com,
        davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Alexander Lobakin <aleksander.lobakin@intel.com>,
        linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org
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On Mon, Oct 9, 2023 at 5:07=E2=80=AFAM Yajun Deng <yajun.deng@linux.dev> wr=
ote:

> '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.