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From:   Jason Xing <kerneljasonxing@gmail.com>
Date:   Tue, 14 Mar 2023 09:54:33 +0800
Message-ID: <CAL+tcoCbvGd_3Mn82vjyy4AXcJntZG2rL1bnJP81H0T+=j2+7w@mail.gmail.com>
Subject: Re: [PATCH net-next] net-sysfs: display two backlog queue len separately
To:     Eric Dumazet <edumazet@google.com>
Cc:     davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jason Xing <kernelxing@tencent.com>
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On Tue, Mar 14, 2023 at 1:34=E2=80=AFAM Eric Dumazet <edumazet@google.com> =
wrote:
>
> On Mon, Mar 13, 2023 at 10:16=E2=80=AFAM Jason Xing <kerneljasonxing@gmai=
l.com> wrote:
>
> >
> > Thanks for the guidance. Scaling is a good way to go really. But I
> > just would like to separate these two kinds of limits to watch them
> > closely. More often we cannot decide to adjust accurately which one
> > should be adjusted. Time squeeze may not be clear and we cannot
> > randomly write a larger number into both proc files which may do harm
> > to some external customers unless we can show some proof to them.
> >
> > Maybe I got something wrong. If adding some tracepoints for those
> > limits in softnet_data is not elegant, please enlighten me :)
> >
>
[...]
> I dunno, but it really looks like you are re-discovering things that
> we dealt with about 10 years ago.
>
> I wonder why new ways of tracing stuff are needed nowadays, while ~10
> years ago nothing
> officially put and maintained forever in the kernel was needed.

Well, that's not my original intention. All I want to do is show more
important members in softnet_data to help users know more about this
part and decide which one to tune.

I think what you said (which is "You can not pretend the sum is zero,
some user space tools out there
would be fooled.") is quite right, I can keep this
softnet_backlog_len() untouched as the old days.

Thanks,
Jason