Date: Tue, 13 Nov 2012 11:48:39 +0100
From: Steffen Klassert <steffen.klassert@secunet.com>
To: Shan Wei <shanwei88@gmail.com>
Cc: Christoph Lameter <cl@linux.com>, David Miller <davem@davemloft.net>,
        NetDev <netdev@vger.kernel.org>,
        Herbert Xu <herbert@gondor.hengli.com.au>,
        Kernel-Maillist <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 3/9] net: xfrm: use __this_cpu_read per-cpu helper
Message-ID: <20121113104839.GJ22290@secunet.com>
References: <50A1A7C9.3060703@gmail.com>
 <20121113072101.GG22290@secunet.com>
 <50A213DF.1040103@gmail.com>
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On Tue, Nov 13, 2012 at 05:33:19PM +0800, Shan Wei wrote:
> Steffen Klassert said, at 2012/11/13 15:21:
> > 
> > This should just fetch the tfm pointer, so why exactly __this_cpu_read
> > is better than __this_cpu_ptr? Please keep in mind that performance is
> > not the most important thing here. It's much more important that it
> > works in any case.
>  
> [0/9] describes why we should submit this series patches.
> you are not included in original mail.
> 
> this_cpu_ptr relocates and address. this_cpu_read() relocates the address
> and performs the fetch. If you want to operate on rda(defined as per_cpu) 
> then you can only use this_cpu_ptr. this_cpu_read() saves you more instructions
> since it can do the relocation and the fetch in one instruction.
> 

Ok, so please add a commit message to describe your changes.

Thanks.
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