From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
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 16:58:16 -0800 [thread overview]
Message-ID: <20080305005816.GG9517@linux.vnet.ibm.com> (raw)
In-Reply-To: <Pine.LNX.4.58.0803041553240.11062@gandalf.stny.rr.com>
On Tue, Mar 04, 2008 at 03:55:42PM -0500, Steven Rostedt wrote:
>
> 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.
So how about if I replace it with comment lines (starting with "#",
not with "comment")?
Thanx, Paul
next prev parent reply other threads:[~2008-03-05 0:58 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
2008-03-05 0:58 ` Paul E. McKenney [this message]
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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