From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [ofa-general] Re: [PATCH 2/3][NET_BATCH] net core use batching Date: Fri, 12 Oct 2007 20:29:49 +0200 Message-ID: <20071012182949.GB12933@one.firstfloor.org> References: <20071010003716.GB552@one.firstfloor.org> <36D9DB17C6DE9E40B059440DB8D95F5203887DD1@orsmsx418.amr.corp.intel.com> <20071012100500.02255243@freepuppy.rosehill> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Brandeburg, Jesse" , Andi Kleen , David Miller , hadi@cyberus.ca, jeff@garzik.org, johnpol@2ka.mipt.ru, herbert@gondor.apana.org.au, gaagaan@gmail.com, Robert.Olsson@data.slu.se, netdev@vger.kernel.org, rdreier@cisco.com, "Waskiewicz Jr, Peter P" , mcarlson@broadcom.com, jagana@us.ibm.com, general@lists.openfabrics.org, mchan@broadcom.com, tgraf@suug.ch, randy.dunlap@oracle.com, sri@us.ibm.com, kaber@trash.net To: Stephen Hemminger Return-path: Received: from one.firstfloor.org ([213.235.205.2]:41268 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754851AbXJLS3v (ORCPT ); Fri, 12 Oct 2007 14:29:51 -0400 Content-Disposition: inline In-Reply-To: <20071012100500.02255243@freepuppy.rosehill> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org > Use RCU? or write a generic version and get it reviewed. You really > want someone with knowledge of all the possible barrier impacts to > review it. I guess he was thinking of using cmpxchg; but we don't support this in portable code. RCU is not really suitable for this because it assume writing is relatively rare which is definitely not the case for a qdisc. Also general list management with RCU is quite expensive anyways -- it would require a full copy (that is the 'C' in RCU which Linux generally doesn't use at all) -Andi