Date: Tue, 15 Jun 2010 18:16:59 -0700 (PDT)
Message-Id: <20100615.181659.58428840.davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: alexander.h.duyck@intel.com, jeffrey.t.kirsher@intel.com, mingo@redhat.com,
       tglx@linutronix.de, hpa@zytor.com, x86@kernel.org,
       linux-kernel@vger.kernel.org, netdev@vger.kernel.org, gospo@redhat.com
Subject: Re: [PATCH net-next-2.6] net: NET_SKB_PAD should depend on
 L1_CACHE_BYTES
From: David Miller <davem@davemloft.net>
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	<20100610.222006.242136751.davem@davemloft.net>
	<1276520234.2478.82.camel@edumazet-laptop>
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 14 Jun 2010 14:57:14 +0200

> [PATCH net-next-2.6] net: NET_SKB_PAD should depend on L1_CACHE_BYTES
> 
> In old kernels, NET_SKB_PAD was defined to 16.
> 
> Then commit d6301d3dd1c2 (net: Increase default NET_SKB_PAD to 32), and
> commit 18e8c134f4e9 (net: Increase NET_SKB_PAD to 64 bytes) increased it
> to 64.
> 
> While first patch was governed by network stack needs, second was more
> driven by performance issues on current hardware. Real intent was to
> align data on a cache line boundary.
> 
> So use max(32, L1_CACHE_BYTES) instead of 64, to be more generic.
> 
> Remove microblaze and powerpc own NET_SKB_PAD definitions.
> 
> Thanks to Alexander Duyck and David Miller for their comments.
> 
> Suggested-by: David Miller <davem@davemloft.net>
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied, thanks Eric.
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