Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20190903154340.860299-1-rkrcmar@redhat.com> <20190903154340.860299-3-rkrcmar@redhat.com>
 <a2924d91-df68-42de-0709-af53649346d5@arm.com> <20190904042310.GA159235@google.com>
 <20190904104332.ogsjtbtuadhsglxh@e107158-lin.cambridge.arm.com> <20190904130628.GE144846@google.com>
In-Reply-To: <20190904130628.GE144846@google.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Wed, 4 Sep 2019 08:25:27 -0700
Message-ID: <CAADnVQJzgTRWUAaH+L6qwJvHk0vsLPX3eWdZNUr5X77TuEgvPw@mail.gmail.com>
Subject: Re: [PATCH 2/2] sched/debug: add sched_update_nr_running tracepoint
To:     Joel Fernandes <joel@joelfernandes.org>
Cc:     Qais Yousef <qais.yousef@arm.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        =?UTF-8?Q?Jirka_Hladk=C3=BD?= <jhladky@redhat.com>,
        =?UTF-8?B?SmnFmcOtIFZvesOhcg==?= <jvozar@redhat.com>,
        X86 ML <x86@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Sep 4, 2019 at 6:10 AM Joel Fernandes <joel@joelfernandes.org> wrote:
>
> I wonder if this distinction of "tracepoint" being non-ABI can be documented
> somewhere. I would be happy to do that if there is a place for the same. I
> really want some general "policy" in the kernel on where we draw a line in
> the sand with respect to tracepoints and ABI :).

It's been discussed millions times. tracepoints are not abi.
Example: android folks started abusing tracepoints inside bpf core
and we _deleted_ them.
Same thing can be done with _any_ tracepoint.
Do not abuse them and stop the fud about abi.