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From: Huang Ying <ying.huang@intel.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Tejun Heo <tj@kernel.org>,
	Christoph Lameter <cl@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: What is the difference between percpu_xxx and this_cpu_xxx?
Date: Tue, 13 Sep 2011 14:14:06 +0800	[thread overview]
Message-ID: <4E6EF4AE.4030503@intel.com> (raw)
In-Reply-To: <1315894267.2556.21.camel@edumazet-laptop>

Hi, Eric,

On 09/13/2011 02:11 PM, Eric Dumazet wrote:
> Le mardi 13 septembre 2011 à 12:28 +0800, Huang Ying a écrit :
>> Hi,
>>
>> If my understanding was correct, from the kernel source code, it appears
>> that percpu_xxx and this_cpu_xxx have the same semantics and
>> implementation in effect, haven’t them?
>>
>> If so, why do we need two API for the same thing?
> 
> History mostly, and transition.
> 
> percpu_inc() was an x86 only thing
> 
> __get_cpu_var(var)++ -> percpu_inc(var) -> this_cpu_inc(var)

Thanks for clarification.  Is there someone working on the transition?
Is that possible to translate most percpu_xxx to this_cpu_xxx blindly?

Best Regards,
Huang Ying

  reply	other threads:[~2011-09-13  6:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-13  4:28 What is the difference between percpu_xxx and this_cpu_xxx? Huang Ying
2011-09-13  6:11 ` Eric Dumazet
2011-09-13  6:14   ` Huang Ying [this message]
2011-09-13  7:40     ` Tejun Heo

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