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From: Marco Elver <elver@google.com>
Date: Wed, 10 Apr 2024 15:59:07 +0200
Message-ID: <CANpmjNNFcHp0n5J5XWMb=3cpa+FT5V1xeev5dFZCC7SknPBkOA@mail.gmail.com>
Subject: Re: [PATCH] tracing: Add new_exec tracepoint
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>, Eric Biederman <ebiederm@xmission.com>, 
	Kees Cook <keescook@chromium.org>, Alexander Viro <viro@zeniv.linux.org.uk>, 
	Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>, 
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, linux-mm@kvack.org, 
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-trace-kernel@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>
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On Wed, 10 Apr 2024 at 15:56, Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> On Mon,  8 Apr 2024 11:01:54 +0200
> Marco Elver <elver@google.com> wrote:
>
> > Add "new_exec" tracepoint, which is run right after the point of no
> > return but before the current task assumes its new exec identity.
> >
> > Unlike the tracepoint "sched_process_exec", the "new_exec" tracepoint
> > runs before flushing the old exec, i.e. while the task still has the
> > original state (such as original MM), but when the new exec either
> > succeeds or crashes (but never returns to the original exec).
> >
> > Being able to trace this event can be helpful in a number of use cases:
> >
> >   * allowing tracing eBPF programs access to the original MM on exec,
> >     before current->mm is replaced;
> >   * counting exec in the original task (via perf event);
> >   * profiling flush time ("new_exec" to "sched_process_exec").
> >
> > Example of tracing output ("new_exec" and "sched_process_exec"):
>
> nit: "new_exec" name a bit stands out compared to other events, and hard to
> expect it comes before or after "sched_process_exec". Since "begin_new_exec"
> is internal implementation name, IMHO, it should not exposed to user.
> What do you think about calling this "sched_prepare_exec" ?

I like it, I'll rename it to sched_prepare_exec.

Thanks!