netdev - Re: [PATCH] tcp: tcp_drop adds `SNMP` and `reason` parameter for tracing

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Message-ID: <20210920132440.7a2febce@oasis.local.home>
Date:   Mon, 20 Sep 2021 13:24:40 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Cong Wang <xiyou.wangcong@...il.com>
Cc:     Zhongya Yan <yan2228598786@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Brendan Gregg <brendan.d.gregg@...il.com>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        David Miller <davem@...emloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        David Ahern <dsahern@...nel.org>, Yonghong Song <yhs@...com>,
        Zhongya Yan <2228598786@...com>
Subject: Re: [PATCH] tcp: tcp_drop adds `SNMP` and `reason` parameter for
 tracing

On Mon, 20 Sep 2021 10:20:33 -0700
Cong Wang <xiyou.wangcong@...il.com> wrote:

> > The strings were requested by the networking maintainers.
> >
> >   https://lore.kernel.org/all/CANn89iJO8jzjFWvJ610TPmKDE8WKi8ojTr_HWXLz5g=4pdQHEA@mail.gmail.com/  
> 
> I think you misunderstand my point. Eric's point is hex address
> vs. string, which I never disagree. With SNMP enum, user-space
> can easily interpret it to string too, so at the end you still get strings
> but not from kernel. This would at least save a handful of strings
> from vmlinux, especially if we expand it beyond TCP.

If an enum is saved in the ring buffer, it is also trivial to have it
show a string in the buffer, as there's a way to map enums to strings
on output as well. Which I discussed in that same thread.

-- Steve