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Date: Tue, 19 Dec 2023 17:17:19 -0800
From: "Paul E. McKenney" <paulmck@kernel.org>
To: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: RCU <rcu@vger.kernel.org>, Neeraj upadhyay <Neeraj.Upadhyay@amd.com>,
	Boqun Feng <boqun.feng@gmail.com>, Hillf Danton <hdanton@sina.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>,
	Frederic Weisbecker <frederic@kernel.org>
Subject: Re: [PATCH v3 3/7] doc: Add rcutree.rcu_normal_wake_from_gp to
 kernel-parameters.txt
Message-ID: <1aa6e7a4-57de-480f-bc1c-5a1b28dd666b@paulmck-laptop>
Reply-To: paulmck@kernel.org
References: <20231128080033.288050-1-urezki@gmail.com>
 <20231128080033.288050-4-urezki@gmail.com>
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On Tue, Nov 28, 2023 at 09:00:29AM +0100, Uladzislau Rezki (Sony) wrote:
> This commit adds rcutree.rcu_normal_wake_from_gp description
> to the kernel-parameters.txt file.
> 
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

Very good, but could you please fold this into the first patch, which
is the one that adds this kernel parameter?

							Thanx, Paul

> ---
>  Documentation/admin-guide/kernel-parameters.txt | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 0a1731a0f0ef..65bfbfb09522 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4944,6 +4944,20 @@
>  			this kernel boot parameter, forcibly setting it
>  			to zero.
>  
> +	rcutree.rcu_normal_wake_from_gp= [KNL]
> +			Reduces a latency of synchronize_rcu() call. This approach
> +			maintains its own track of synchronize_rcu() callers, so it
> +			does not interact with regular callbacks because it does not
> +			use a call_rcu[_hurry]() path. Please note, this is for a
> +			normal grace period.
> +
> +			How to enable it:
> +
> +			echo 1 > /sys/module/rcutree/parameters/rcu_normal_wake_from_gp
> +			or pass a boot parameter "rcutree.rcu_normal_wake_from_gp=1"
> +
> +			Default is 0.
> +
>  	rcuscale.gp_async= [KNL]
>  			Measure performance of asynchronous
>  			grace-period primitives such as call_rcu().
> -- 
> 2.39.2
>