From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: Who's allowed to set a skb destructor? Date: Thu, 5 Jul 2007 15:06:40 +0200 Message-ID: <20070705130640.GA24731@one.firstfloor.org> References: <20070705122849.GA4759@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , Brice Goglin , netdev@vger.kernel.org, Evgeniy Polyakov , Divy Le Ray To: Jarek Poplawski Return-path: Received: from one.firstfloor.org ([213.235.205.2]:46186 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757782AbXGENGo (ORCPT ); Thu, 5 Jul 2007 09:06:44 -0400 Content-Disposition: inline In-Reply-To: <20070705122849.GA4759@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Jul 05, 2007 at 02:28:50PM +0200, Jarek Poplawski wrote: > I wonder if it's very unsound to think about a one way list > of destructors. Of course, not owners could only clean their > private allocations. Woudn't this save some skb clonning, > copying or adding new fields for private infos? skb cloning isn't very expensive when you need it. And they got a little private area you can use for your own stuff while you have it queued (skb->cb) As a historical note one of the big changes during the Linux 2.0 and 2.1 TCP rewrite was that TCP was changed to always clone for the retransmit queue. This cleaned up the code greatly and fixed many problems. Cloning was also especially optimized for this. When TCP which is about one of the most performance critical protocols around can afford it likely other code can too. -Andi