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From: Steven Rostedt <rostedt@goodmis.org>
To: patrick wang <patrick.wang.shcn@gmail.com>
Cc: paulmck@kernel.org, frederic@kernel.org,
	quic_neeraju@quicinc.com, josh@joshtriplett.org,
	mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
	joel@joelfernandes.org, rcu@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] rcu: ftrace: avoid tracing a few functions executed in multi_cpu_stop()
Date: Fri, 22 Apr 2022 11:52:34 -0400	[thread overview]
Message-ID: <20220422115234.613436e4@gandalf.local.home> (raw)
In-Reply-To: <CAGcnep9Ez-S962vukR_a=otzcSxDRo5HUW2vG_YCBanCfURGXw@mail.gmail.com>

On Fri, 22 Apr 2022 18:45:46 +0800
patrick wang <patrick.wang.shcn@gmail.com> wrote:

> Yes, and not just RISC-V. It's arch-independent. It's the internal change of
> stop machine implementation.
> 
> ----------------------------------------------------------------
> Former stop machine wait loop:
> do {
>     cpu_relax(); => macro
>     ...
> } while (curstate != STOPMACHINE_EXIT);
> -----------------------------------------------------------------
> Current stop machine wait loop:
> do {
>     stop_machine_yield(cpumask); => function (notraced)
>     ...
>     touch_nmi_watchdog(); => function (notraced, inside calls also notraced)
>     ...
>     rcu_momentary_dyntick_idle(); => function (notraced, inside calls traced)
> } while (curstate != MULTI_STOP_EXIT);
> ------------------------------------------------------------------

That makes much more sense. Can you add that to the change log.

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

  reply	other threads:[~2022-04-22 15:52 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-18  4:37 [PATCH] rcu: ftrace: avoid tracing a few functions executed in multi_cpu_stop() Patrick Wang
2022-04-18 16:28 ` Paul E. McKenney
2022-04-18 18:34 ` Steven Rostedt
2022-04-19  4:06   ` patrick wang
2022-04-20 10:34     ` patrick wang
2022-04-20 15:44       ` Steven Rostedt
2022-04-20 16:26         ` Steven Rostedt
2022-04-21 11:36           ` patrick wang
2022-04-21 12:50             ` Steven Rostedt
2022-04-22 10:45               ` patrick wang
2022-04-22 15:52                 ` Steven Rostedt [this message]
2022-04-23  9:43                   ` patrick wang

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