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From: Pavel Machek <pavel@ucw.cz>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Valdis.Kletnieks@vt.edu,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: RCU Kconfig help text
Date: Sun, 6 Sep 2009 22:07:01 +0200	[thread overview]
Message-ID: <20090906200700.GA12714@elf.ucw.cz> (raw)
In-Reply-To: <20090906063927.GG7181@linux.vnet.ibm.com>

> > > > This leaves somebody who has a laptop wondering which choice is best for
> > > > a system with only one or two cores that has CONFIG_PREEMPT defined. One
> > > > choice says it scales down nicely, the other explicitly has a 'depends on
> > > > PREEMPT' attached to it...
> > > > 
> > > > (Yes, I realize in practice, the RCU sections on a laptop are probably usually
> > > > so short they don't matter in practice.  I finally concluded TREE_PREEMPT was
> > > > apparently a rename of CONFIG_PREEMPT_RCU and went with that since that was
> > > > working for me before...)
> > > 
> > > Good point -- I will add the "It also scales down nicely to smaller
> > > systems" to TREE_PREEMPT_RCU.
> > > 
> > > For -really- small systems, TINY_RCU will hopefully be there at some
> > > point, but it can only handle single-CPU systems.
> > 
> > If so, call it 'UP_RCU' or 'UNIPROCESSOR_RCU'?
> 
> "UP_RCU".  Cute!!!  ;-)
> 
> My hope is to drive the RCU selection directly from CONFIG_SMP and
> CONFIG_PREEMPT, so that the choice of RCU would be implicit (aside from
> things like tracing and fanout).
> 
> Seem reasonable, or would you expect anyone to want to hand-select
> the RCU implementation?

Seems reasonable.

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

      reply	other threads:[~2009-09-06 20:07 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-05 13:27 RCU Kconfig help text Valdis.Kletnieks
2009-09-05 20:01 ` Paul E. McKenney
2009-09-06  6:24   ` Pavel Machek
2009-09-06  6:39     ` Paul E. McKenney
2009-09-06 20:07       ` Pavel Machek [this message]

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