Date: Wed, 6 Jun 2012 17:59:10 +0800
From: Zhao Chenhui <chenhui.zhao@freescale.com>
To: Scott Wood <scottwood@freescale.com>
CC: <linuxppc-dev@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>,
        <galak@kernel.crashing.org>, <leoli@freescale.com>
Subject: Re: [PATCH v5 2/5] powerpc/85xx: add HOTPLUG_CPU support
Message-ID: <20120606095910.GB23505@localhost.localdomain>
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On Tue, Jun 05, 2012 at 11:15:52AM -0500, Scott Wood wrote:
> On 06/05/2012 06:18 AM, Zhao Chenhui wrote:
> > On Mon, Jun 04, 2012 at 11:32:47AM -0500, Scott Wood wrote:
> >> On 06/04/2012 06:04 AM, Zhao Chenhui wrote:
> >>> On Fri, Jun 01, 2012 at 04:27:27PM -0500, Scott Wood wrote:
> >>>> On 05/11/2012 06:53 AM, Zhao Chenhui wrote:
> >>>>> -#ifdef CONFIG_KEXEC
> >>>>> +#if defined(CONFIG_KEXEC) || defined(CONFIG_HOTPLUG_CPU)
> >>>>
> >>>> Let's not grow lists like this.  Is there any harm in building it
> >>>> unconditionally?
> >>>>
> >>>> -Scott
> >>>
> >>> We need this ifdef. We only set give_timebase/take_timebase
> >>> when CONFIG_KEXEC or CONFIG_HOTPLUG_CPU is defined.
> >>
> >> If we really need this to be a compile-time decision, make a new symbol
> >> for it, but I really think this should be decided at runtime.  Just
> >> because we have kexec or hotplug support enabled doesn't mean that's
> >> actually what we're doing at the moment.
> >>
> >> -Scott
> > 
> > If user does not enable kexec or hotplug, these codes are redundant.
> > So use CONFIG_KEXEC and CONFIG_HOTPLUG_CPU to gard them.
> 
> My point is that these lists tend to grow and be a maintenance pain.
> For small things it's often better to not worry about saving a few
> bytes.  For larger things that need to be conditional, define a new
> symbol rather than growing ORed lists like this.
> 
> -Scott

I agree with you in principle. But there are only two config options
in this patch, and it is unlikely to grow. 

-Chenhui

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