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Date: Sun, 27 Jan 2008 15:48:53 -0800
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>, linux-kernel@vger.kernel.org
Subject: Re: preemptible RCU bug (was Re: [git pull] scheduler changes for v2.6.25)
Message-ID: <20080127234853.GA10148@linux.vnet.ibm.com>
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References: <20080125203740.GA31784@elte.hu> <479B87B9.8080005@s5r6.in-berlin.de> <20080127110559.GB28315@linux.vnet.ibm.com> <20080127122602.GA17293@elte.hu>
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On Sun, Jan 27, 2008 at 01:26:02PM +0100, Ingo Molnar wrote:
> 
> * Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> 
> > > Sorry, no help available for this option yet.
> > 
> > Good catch!!!
> > 
> > This patch supplies help text for the "RCU implementation type" kernel 
> > configuration choice.
> 
> thanks applied to sched.git. (see the patch below - the config option is 
> in init/Kconfig in mainline, not in kernel/Kconfig.preempt)

Ah missed that -- thank you for retargeting the patch.

							Thanx, Paul

> 	Ingo
> 
> ------------->
> Subject: RCU: add help text for "RCU implementation type"
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> 
> This patch supplies help text for the "RCU implementation type"
> kernel configuration choice.
> 
> Reported-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
> 
>  init/Kconfig |    8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> Index: linux/init/Kconfig
> ===================================================================
> --- linux.orig/init/Kconfig
> +++ linux/init/Kconfig
> @@ -779,6 +779,14 @@ config PREEMPT_NOTIFIERS
>  choice
>  	prompt "RCU implementation type:"
>  	default CLASSIC_RCU
> +	help
> +	  This allows you to choose either the classic RCU implementation
> +	  that is designed for best read-side performance on non-realtime
> +	  systems, or the preemptible RCU implementation for best latency
> +	  on realtime systems.  Note that some kernel preemption modes
> +	  will restrict your choice.
> +
> +	  Select the default if you are unsure.
> 
>  config CLASSIC_RCU
>  	bool "Classic RCU"