Date: Sat, 28 Jan 2006 16:55:49 -0800
From: Andrew Morton <akpm@osdl.org>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: dada1@cosmosbay.com, kiran@scalex86.org, davem@davemloft.net,
       linux-kernel@vger.kernel.org, shai@scalex86.org, netdev@vger.kernel.org,
       pravins@calsoftinc.com
Subject: Re: [patch 3/4] net: Percpufy frequently used variables --
 proto.sockets_allocated
Message-Id: <20060128165549.262f2b90.akpm@osdl.org>
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Benjamin LaHaise <bcrl@kvack.org> wrote:
>
> On Sat, Jan 28, 2006 at 01:28:20AM +0100, Eric Dumazet wrote:
> > We might use atomic_long_t only (and no spinlocks)
> > Something like this ?
> 
> Erk, complex and slow...  Try using local_t instead, which is substantially 
> cheaper on the P4 as it doesn't use the lock prefix and act as a memory 
> barrier.  See asm/local.h.
> 

local_t isn't much use until we get rid of asm-generic/local.h.  Bloaty,
racy with nested interrupts.

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