Date: Fri, 13 Jun 2014 14:24:17 -0400
From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@gentwo.org>
Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 02/12] percpu: introduce arch_raw_cpu_ptr()
Message-ID: <20140613182417.GA3723@htj.dyndns.org>
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On Fri, Jun 13, 2014 at 12:10:36PM -0500, Christoph Lameter wrote:
> On Thu, 12 Jun 2014, Tejun Heo wrote:
> 
> > Currently, archs can override raw_cpu_ptr() directly; however, we
> > wanna build a layer of indirection in the generic part of percpu so
> > that we can implement generic features there without affecting archs.
> 
> Not sure why one would do this. We already have this_cpu_ptr() (arch
> independant) and the lower level raw_cpu_ptr() which can be modified by
> the arch code.

So that there's separate between generic part of definition and
arch-specific part.  This allows the generic portion of definition to
be handled in the generic code.  e.g. arch no longer has to worry
about verifying arguments or having a data dependency barrier.  It
just has to worry about the core implementation.  The generic layer
can handle the boilerplates.

Thanks.

-- 
tejun
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