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From: "Paul E. McKenney" <paulmck@kernel.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Josh Triplett <josh@joshtriplett.org>
Subject: Re: [RFC PATCH 12/12] rcu: Nocb (de)activate through sysfs
Date: Mon, 21 Sep 2020 17:26:29 -0700	[thread overview]
Message-ID: <20200922002629.GS29330@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20200921124351.24035-13-frederic@kernel.org>

On Mon, Sep 21, 2020 at 02:43:51PM +0200, Frederic Weisbecker wrote:
> Not for merge.
> 
> Make nocb toggable for a given CPU using:
> 	/sys/devices/system/cpu/cpu*/hotplug/nocb
> 
> This is only intended for those who want to test this patchset. The real
> interfaces will be cpuset/isolation and rcutorture.

Excellent choice for testing in the near term!

How does rcutorture fare with this series if an additional kthread toggles
offloading on and off continually?

All questions and concerns aside, excellent progress and nice work!!!

							Thanx, Paul

> Not-Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> Cc: Paul E. McKenney <paulmck@kernel.org>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Lai Jiangshan <jiangshanlai@gmail.com>
> Cc: Joel Fernandes <joel@joelfernandes.org>
> ---
>  kernel/cpu.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 6ff2578ecf17..a36634113b8e 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -2224,10 +2224,33 @@ static ssize_t show_cpuhp_fail(struct device *dev,
>  
>  static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail);
>  
> +static ssize_t write_nocb(struct device *dev,
> +			  struct device_attribute *attr,
> +			  const char *buf, size_t count)
> +{
> +	int val, ret;
> +
> +	ret = kstrtoint(buf, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val == 0)
> +		rcu_nocb_cpu_deoffload(dev->id);
> +	else if (val == 1)
> +		rcu_nocb_cpu_offload(dev->id);
> +	else
> +		return -EINVAL;
> +
> +	return count;
> +}
> +
> +static DEVICE_ATTR(nocb, 0644, NULL, write_nocb);
> +
>  static struct attribute *cpuhp_cpu_attrs[] = {
>  	&dev_attr_state.attr,
>  	&dev_attr_target.attr,
>  	&dev_attr_fail.attr,
> +	&dev_attr_nocb.attr,
>  	NULL
>  };
>  
> -- 
> 2.28.0
> 

  reply	other threads:[~2020-09-22  0:26 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-21 12:43 [RFC PATCH 00/12] rcu/nocb: De-offload and re-offload support v2 Frederic Weisbecker
2020-09-21 12:43 ` [RFC PATCH 01/12] rcu: Implement rcu_segcblist_is_offloaded() config dependent Frederic Weisbecker
2020-09-22  0:27   ` Paul E. McKenney
2020-09-22 21:43     ` Frederic Weisbecker
2020-09-22 23:11       ` Paul E. McKenney
2020-09-23 15:25         ` Frederic Weisbecker
2020-09-21 12:43 ` [RFC PATCH 02/12] rcu: Turn enabled/offload states into a common flag Frederic Weisbecker
2020-09-21 12:43 ` [RFC PATCH 03/12] rcu: Provide basic callback offloading state machine bits Frederic Weisbecker
2020-09-21 23:50   ` Paul E. McKenney
2020-09-21 12:43 ` [RFC PATCH 04/12] rcu: De-offloading CB kthread Frederic Weisbecker
2020-09-22  0:07   ` Paul E. McKenney
2020-09-21 12:43 ` [RFC PATCH 05/12] rcu: De-offloading GP kthread Frederic Weisbecker
2020-09-22  0:10   ` Paul E. McKenney
2020-09-23 15:31     ` Frederic Weisbecker
2020-09-23 15:48       ` Paul E. McKenney
2020-09-21 12:43 ` [RFC PATCH 06/12] rcu: Re-offload support Frederic Weisbecker
2020-09-21 12:43 ` [RFC PATCH 07/12] rcu: Shutdown nocb timer on de-offloading Frederic Weisbecker
2020-09-22  0:17   ` Paul E. McKenney
2020-09-23 15:29     ` Frederic Weisbecker
2020-09-23 15:47       ` Paul E. McKenney
2020-09-21 12:43 ` [RFC PATCH 08/12] rcu: Flush bypass before setting SEGCBLIST_SOFTIRQ_ONLY Frederic Weisbecker
2020-09-21 12:43 ` [RFC PATCH 09/12] rcu: Set SEGCBLIST_SOFTIRQ_ONLY at the very last stage of de-offloading Frederic Weisbecker
2020-09-21 12:43 ` [RFC PATCH 10/12] rcu: Process batch locally as long as offloading isn't complete Frederic Weisbecker
2020-09-22  0:22   ` Paul E. McKenney
2020-09-21 12:43 ` [RFC PATCH 11/12] rcu: Locally accelerate callbacks " Frederic Weisbecker
2020-09-22  0:24   ` Paul E. McKenney
2020-09-21 12:43 ` [RFC PATCH 12/12] rcu: Nocb (de)activate through sysfs Frederic Weisbecker
2020-09-22  0:26   ` Paul E. McKenney [this message]
2020-09-23 15:27     ` Frederic Weisbecker
2020-09-23 15:47       ` Paul E. McKenney
2020-09-23 19:00         ` Frederic Weisbecker
2020-09-24  0:38           ` Paul E. McKenney

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