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Message-ID: <4A399D52.9040801@kernel.org>
Date: Thu, 18 Jun 2009 10:50:10 +0900
From: Tejun Heo <tj@kernel.org>
MIME-Version: 1.0
Subject: Re: [this_cpu_xx V2 02/19] Introduce this_cpu_ptr() and generic this_cpu_*
 operations
References: <20090617203337.399182817@gentwo.org> <20090617203443.173725344@gentwo.org>
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To: cl@linux-foundation.org
Cc: akpm@linux-foundation.org, linux-mm@kvack.org, David Howells <dhowells@redhat.com>, Ingo Molnar <mingo@elte.hu>, Rusty Russell <rusty@rustcorp.com.au>, Eric Dumazet <dada1@cosmosbay.com>, davem@davemloft.net
List-ID: <linux-mm.kvack.org>

cl@linux-foundation.org wrote:
> this_cpu_ptr
> ------------
> 
> this_cpu_ptr(xx) = per_cpu_ptr(xx, smp_processor_id).
> 
> The problem with per_cpu_ptr(x, smp_processor_id) is that it requires
> an array lookup to find the offset for the cpu. Processors typically
> have the offset for the current cpu area in some kind of (arch dependent)
> efficiently accessible register or memory location.
...
> cc: David Howells <dhowells@redhat.com>
> cc: Tejun Heo <tj@kernel.org>
> cc: Ingo Molnar <mingo@elte.hu>
> cc: Rusty Russell <rusty@rustcorp.com.au>
> cc: Eric Dumazet <dada1@cosmosbay.com>
> Signed-off-by: Christoph Lameter <cl@linux-foundation.org>

Acked-by: Tejun Heo <tj@kernel.org>

-- 
tejun

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