From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: Who's allowed to set a skb destructor? Date: Thu, 5 Jul 2007 15:00:12 +0200 Message-ID: <20070705130012.GB4759@ff.dom.local> References: <20070705122849.GA4759@ff.dom.local> <20070705122847.GA13368@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , Brice Goglin , netdev@vger.kernel.org, Divy Le Ray To: Evgeniy Polyakov Return-path: Received: from mx12.go2.pl ([193.17.41.142]:37217 "EHLO poczta.o2.pl" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755092AbXGEMvo (ORCPT ); Thu, 5 Jul 2007 08:51:44 -0400 Content-Disposition: inline In-Reply-To: <20070705122847.GA13368@2ka.mipt.ru> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Jul 05, 2007 at 04:28:47PM +0400, Evgeniy Polyakov wrote: > Hi, Jarek. > > On Thu, Jul 05, 2007 at 02:28:50PM +0200, Jarek Poplawski (jarkao2@o2.pl) 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? > > There should not be any additional allocations, since they are very > slow, that part of mbuf is really horrible for performance - openbsd > hackers removed additional allocation of mbuf tag in PF code during the > last hackathon, which doubled its performance, that is why skb has only > one control structure and data area, which incorporates additional > control information, thus there is no need for multiple destructors. Of course, my knowledge of this is far not enough, and maybe I got this reversed, but from Andi's words I've understood that linux prefers another (mixed) approach, so I've thought such list should be a consequence... Thanks, Jarek P.