linux-kernel - Re: [PATCH] stop_machine: Mark functions as notrace

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Message-ID: <20201021101522.3d1f3865@gandalf.local.home>
Date:   Wed, 21 Oct 2020 10:15:22 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Zong Li <zong.li@...ive.com>
Cc:     paulmck@...nel.org, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
        joel@...lfernandes.org, vincent.whitchurch@...s.com,
        tglx@...utronix.de, paul.walmsley@...ive.com,
        palmerdabbelt@...gle.com, guoren@...nel.org, atishp@...shpatra.org,
        mhiramat@...nel.org, greentime.hu@...ive.com,
        colin.king@...onical.com, rcu@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH] stop_machine: Mark functions as notrace

On Wed, 21 Oct 2020 10:12:16 -0400
Steven Rostedt <rostedt@...dmis.org> wrote:

> > Fixes: 4ecf0a43e729 ("processor: get rid of cpu_relax_yield")
> > Fixes: 366237e7b083 ("stop_machine: Provide RCU quiescent state in
> > multi_cpu_stop()")  
> 
> I really do not like to add "notrace" to core functions because a single
> architecture has issues with it. Why does RISCV have problems with these
> functions but no other architecture does?
> 
> NACK from me until it is shown that these are issues for a broader set of
> architectures.

After looking at the two above fixes, I take back my NACK ;-)

One of them duplicates an already notraced function, so that looks fine.
The other makes a static function global, which could cause issues as well.

After further review:

Acked-by: Steven Rostedt (VMware) <rostedt@...dmis.org>

-- Steve