From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: skbuff data pointer alignment requirement Date: Sat, 22 Dec 2007 12:00:57 +0100 Message-ID: <476CEE69.20902@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Keyur Chudgar Return-path: Received: from ug-out-1314.google.com ([66.249.92.168]:42439 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780AbXLVK7G (ORCPT ); Sat, 22 Dec 2007 05:59:06 -0500 Received: by ug-out-1314.google.com with SMTP id z38so768483ugc.16 for ; Sat, 22 Dec 2007 02:59:04 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Keyur Chudgar wrote, On 12/21/2007 02:12 AM: ... > If some hardware requirements, for example is, they need to have 256 > bytes aligned address for them to do the DMA, no matter what the > packet size is. In this kind of cases, can you guide me what should I > do? Is there any way already in Linux I can do this? ... > In the above specified situation, I can define SKB_ADDR_MIN_ALIGN = > 256 in my Makefile or I don't define it at all if I am okay with > default alignment size. Do you mean hardware requirements of an architecture or a specific driver? So, if you have more than one network card, is it needed by all of them, while other (not network) drivers are happy with default allocations? Regards, Jarek P.