From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Jiri Olsa <olsajiri@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Ingo Molnar <mingo@redhat.com>, bpf <bpf@vger.kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [RFC] ftrace: Add support to keep some functions out of ftrace
Date: Mon, 15 Aug 2022 17:48:44 +0200 [thread overview]
Message-ID: <Yvpq3JDk8fTgdMv8@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <CAADnVQJuDS22o7fi9wPZx9siAWgu1grQXXB02KfasxZ-RPdRSw@mail.gmail.com>
On Mon, Aug 15, 2022 at 08:35:53AM -0700, Alexei Starovoitov wrote:
> On Mon, Aug 15, 2022 at 8:28 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Mon, Aug 15, 2022 at 08:17:42AM -0700, Alexei Starovoitov wrote:
> > > It's hiding a fake function from ftrace, since it's not a function
> > > and ftrace infra shouldn't show it tracing logs.
> > > In other words it's a _notrace_ function with nop5.
> >
> > Then make it a notrace function with a nop5 in it. That isn't hard.
>
> That's exactly what we're trying to do.
All the while claiming ftrace is broken while it is not.
> Jiri's patch is one way to achieve that.
Fairly horrible way.
> What is your suggestion?
Mailed it already.
> Move it from C to asm ?
Would be much better than proposed IMO.
> Make it naked function with explicit inline asm?
Can be made to work but is iffy because the compiler can do horrible
things with placing the asm().
next prev parent reply other threads:[~2022-08-15 15:49 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220722110811.124515-1-jolsa@kernel.org>
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[not found] ` <CAADnVQ+hLnyztCi9aqpptjQk-P+ByAkyj2pjbdD45dsXwpZ0bw@mail.gmail.com>
[not found] ` <20220722120854.3cc6ec4b@gandalf.local.home>
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[not found] ` <YtxqjxJVbw3RD4jt@krava>
[not found] ` <YvbDlwJCTDWQ9uJj@krava>
2022-08-13 19:02 ` [RFC] ftrace: Add support to keep some functions out of ftrace Steven Rostedt
2022-08-14 11:32 ` Steven Rostedt
2022-08-14 15:22 ` Jiri Olsa
2022-08-15 2:07 ` Chen Zhongjin
2022-08-15 8:04 ` Jiri Olsa
2022-08-15 11:01 ` Björn Töpel
2022-08-15 11:29 ` Jiri Olsa
2022-08-15 12:19 ` Björn Töpel
2022-08-15 12:30 ` Björn Töpel
2022-08-15 8:03 ` Peter Zijlstra
2022-08-15 9:44 ` Jiri Olsa
2022-08-15 12:37 ` Peter Zijlstra
2022-08-15 14:25 ` Alexei Starovoitov
2022-08-15 14:33 ` Peter Zijlstra
2022-08-15 14:45 ` Alexei Starovoitov
2022-08-15 15:02 ` Peter Zijlstra
2022-08-15 15:17 ` Alexei Starovoitov
2022-08-15 15:28 ` Peter Zijlstra
2022-08-15 15:35 ` Alexei Starovoitov
2022-08-15 15:44 ` Steven Rostedt
2022-08-15 15:53 ` Alexei Starovoitov
2022-08-15 16:13 ` Steven Rostedt
2022-08-15 15:48 ` Peter Zijlstra [this message]
2022-08-16 6:56 ` Jiri Olsa
2022-08-17 9:29 ` Jiri Olsa
2022-08-17 16:57 ` Alexei Starovoitov
2022-08-17 19:39 ` Jiri Olsa
2022-08-15 15:41 ` Peter Zijlstra
2022-08-15 15:49 ` Alexei Starovoitov
2022-08-15 16:08 ` Steven Rostedt
2022-08-18 20:27 ` Jiri Olsa
2022-08-18 20:50 ` Steven Rostedt
2022-08-18 21:00 ` Alexei Starovoitov
2022-08-18 21:05 ` Steven Rostedt
2022-08-18 21:32 ` Jiri Olsa
2022-08-19 11:45 ` Jiri Olsa
2022-08-23 17:23 ` Alexei Starovoitov
2022-08-26 8:00 ` Jiri Olsa
2022-08-18 21:14 ` Jiri Olsa
2022-08-15 15:32 ` Steven Rostedt
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