From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH v2] introduce and use relaxed cpumask bitops
Date: Wed, 18 Feb 2015 12:48:45 +0000
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To: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>, George Dunlap <George.Dunlap@eu.citrix.com>, Ian Jackson <Ian.Jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>, Andrew Cooper <andrew.cooper3@citrix.com>, xen-devel <xen-devel@lists.xenproject.org>
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On Wed, 2015-02-11 at 13:42 +0000, Jan Beulich wrote:
> Using atomic (LOCKed on x86) bitops for certain of the operations on
> cpumask_t is overkill when the variables aren't concurrently accessible
> (e.g. local function variables, or due to explicit locking). Introduce
> alternatives using non-atomic bitops and use them where appropriate.
> 
> Note that this
> - adds a volatile qualifier to cpumask_test_and_{clear,set}_cpu()
>   (should have been there from the beginning, like is the case for
>   cpumask_{clear,set}_cpu())
> - replaces several cpumask_clear()+cpumask_set_cpu(, n) pairs by the
>   simpler cpumask_copy(, cpumask_of(n)) (or just cpumask_of(n) if we
>   can do without copying)
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Acked-by: George Dunlap <george.dunlap@eu.citrix.com>

AIUI there is no need for any arm changes (you reuse the existing
__clear_bit etc), so:
Acked-by: Ian Campbell <ian.campbell@citrix.com>

I suppose at some point we might want to switch xen/arch/arm to use the
relaxed ops where appropriate, but no need for you to worry about that.

Ian