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Date: Fri, 25 Jul 2008 17:30:57 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Mike Travis <travis@sgi.com>
CC: Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Hugh Dickins <hugh@veritas.com>, Jack Steiner <steiner@sgi.com>,
       "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/4] x86_64: Optimize percpu accesses
References: <20080725211117.586723000@polaris-admin.engr.sgi.com> <488A613E.50305@goop.org> <488A6F5F.5000105@sgi.com>
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Mike Travis wrote:
> Yes, you're right, I wrote that quickly without really reading it back.
> My point is that now that x86_read_percpu() and x86_write_percpu() do
> evaluate to a single instruction (by definition atomic), then it doesn't
> need to be surrounded by the preempt_disable()/preempt_enable() calls.
>   

Yep, correct.

> It appears as if I'm implying that's the case for get/put_cpu_var().
>   

Right.

    J