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From: Steven Rostedt <rostedt@goodmis.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
	ego@in.ibm.com, Ingo Molnar <mingo@elte.hu>,
	Dipankar Sarma <dipankar@in.ibm.com>, Ted Tso <tytso@us.ibm.com>,
	dvhltc@us.ibm.com, Oleg Nesterov <oleg@tv-sign.ru>,
	Andrew Morton <akpm@linux-foundation.org>,
	bunk@kernel.org, Josh Triplett <josh@freedesktop.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	zippel@linux-m68k.org
Subject: Re: [PATCH] move PREEMPT_RCU config option back under PREEMPT
Date: Tue, 4 Mar 2008 15:55:42 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.58.0803041553240.11062@gandalf.stny.rr.com> (raw)
In-Reply-To: <20080304202207.GA10926@linux.vnet.ibm.com>


On Tue, 4 Mar 2008, Paul E. McKenney wrote:
>
> The original preemptible-RCU patch put the choice between classic and
> preemptible RCU into kernel/Kconfig.preempt, which resulted in build
> failures on machines not supporting CONFIG_PREEMPT.  This choice was
> therefore moved to init/Kconfig, which worked, but placed the choice
> between classic and preemptible RCU at the top level, a very obtuse choice
> indeed.  This patch changes from the Kconfig "choice" mechanism to a pair
> of booleans, only one of which (CONFIG_PREEMPT_RCU) is user-visible,
> and is located in kernel/Kconfig.preempt, where one would expect it
> to be.  The other (CONFIG_CLASSIC_RCU) is in init/Kconfig so that it
> is available to all architectures, hopefully avoiding build breakage.
> Thanks to Roman Zippel for suggesting this approach.
>
> I have tested this, but sadly do not have access to a machine that does
> not support CONFIG_PREEMPT.  However, I did edit my config in an attempt
> to simulate this situation.

One minor comment, but otherwise:

Acked-by: Steven Rostedt <srostedt@redhat.com>

>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>


>  config CLASSIC_RCU
> -	bool "Classic RCU"
> +	def_bool !PREEMPT_RCU
>  	help
>  	  This option selects the classic RCU implementation that is
>  	  designed for best read-side performance on non-realtime
> -	  systems.
> -
> -	  Say Y if you are unsure.
> -

You can get rid of the "help" part since it isn't visible to users.

-- Steve


  reply	other threads:[~2008-03-04 20:56 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-13 17:03 [RFC PATCH 0/6] RCU: Preemptible-RCU Gautham R Shenoy
2007-12-13 17:14 ` [RFC PATCH 1/6] Preempt-RCU: Use softirq instead of tasklets for RCU Gautham R Shenoy
2007-12-13 17:15 ` [RFC PATCH 2/6] Preempt-RCU: Reorganize RCU code into rcuclassic.c and rcupdate.c Gautham R Shenoy
2007-12-14 14:51   ` Johannes Weiner
2007-12-14 16:12     ` Paul E. McKenney
2007-12-13 17:16 ` [RFC PATCH 3/6] Preempt-RCU: Fix rcu_barrier for preemptive environment Gautham R Shenoy
2007-12-13 17:16 ` [RFC PATCH 4/6] Preempt-RCU: Implementation Gautham R Shenoy
2008-02-29  4:34   ` Roman Zippel
2008-02-29  4:53     ` Paul E. McKenney
2008-02-29 12:38       ` Roman Zippel
2008-02-29 13:55         ` Steven Rostedt
2008-03-01 19:39         ` Paul E. McKenney
2008-03-01 21:07           ` Steven Rostedt
2008-03-02  3:09             ` Roman Zippel
2008-03-02  3:06           ` Roman Zippel
2008-03-03 18:55             ` Paul E. McKenney
2008-03-04 20:22               ` [PATCH] move PREEMPT_RCU config option back under PREEMPT Paul E. McKenney
2008-03-04 20:55                 ` Steven Rostedt [this message]
2008-03-05  0:58                   ` Paul E. McKenney
2008-03-05  2:06                     ` Roman Zippel
2008-03-05 19:00                       ` Paul E. McKenney
2008-03-04 20:49               ` [RFC PATCH 4/6] Preempt-RCU: Implementation Roman Zippel
2008-02-29 13:53     ` Steven Rostedt
2008-02-29 14:31       ` Roman Zippel
2007-12-13 17:17 ` [RFC PATCH 5/6] Preempt-RCU: CPU Hotplug handling Gautham R Shenoy
2007-12-13 17:18 ` [RFC PATCH 6/6] Preempt-RCU: Update RCU Documentation Gautham R Shenoy
2007-12-13 20:42   ` Ingo Molnar
2007-12-13 21:06     ` Gautham R Shenoy
2007-12-13 17:36 ` [RFC PATCH 0/6] RCU: Preemptible-RCU Steven Rostedt
2007-12-13 20:42   ` Ingo Molnar
2007-12-13 20:56     ` Steven Rostedt
2007-12-13 21:09   ` Gautham R Shenoy
2007-12-13 20:38 ` Ingo Molnar
2007-12-13 23:41   ` Paul E. McKenney

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