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Date: Wed, 5 Jun 2024 15:07:49 +0100
From: Mark Rutland <mark.rutland@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Florent Revest <revest@chromium.org>,
	Martin KaFai Lau <martin.lau@linux.dev>, bpf <bpf@vger.kernel.org>,
	Sven Schnelle <svens@linux.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alan Maguire <alan.maguire@oracle.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>, Guo Ren <guoren@kernel.org>
Subject: Re: [PATCH v3 00/27] function_graph: Allow multiple users for
 function graph tracing
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References: <20240603190704.663840775@goodmis.org>
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On Mon, Jun 03, 2024 at 03:07:04PM -0400, Steven Rostedt wrote:
> This is a continuation of the function graph multi user code.
> I wrote a proof of concept back in 2019 of this code[1] and
> Masami started cleaning it up. I started from Masami's work v10
> that can be found here:
> 
>  https://lore.kernel.org/linux-trace-kernel/171509088006.162236.7227326999861366050.stgit@devnote2/
> 
> This is *only* the code that allows multiple users of function
> graph tracing. This is not the fprobe work that Masami is working
> to add on top of it. As Masami took my proof of concept, there
> was still several things I disliked about that code. Instead of
> having Masami clean it up even more, I decided to take over on just
> my code and change it up a bit.

FWIW, this is useful to me as-is for testing stacktracing.

Before this series I had some horrid hacks to manipulate the global
filters, and after this series I just need to manipulate the filters in
fgraph_ops::ops, which is *much* nicer.

I've pushed out my WIP to:

  https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=stacktrace/tests

... which is all to say, this is useful and I've given this some testing
beyond the usual ftrace tests.

Mark.