From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: Qdisc->u32_node - licence to kill Date: Wed, 9 Aug 2017 14:48:34 +0200 Message-ID: <20170809124834.GC1867@nanopsycho> References: <20170807164100.GK2085@nanopsycho.orion> <5988A7A2.3090200@gmail.com> <20170807190624.GL2085@nanopsycho.orion> <5988C55B.60204@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Cong Wang , John Fastabend , David Miller , Linux Kernel Network Developers , mlxsw@mellanox.com To: Jamal Hadi Salim Return-path: Received: from mail-wm0-f48.google.com ([74.125.82.48]:34901 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751987AbdHIMsg (ORCPT ); Wed, 9 Aug 2017 08:48:36 -0400 Received: by mail-wm0-f48.google.com with SMTP id m85so30988686wma.0 for ; Wed, 09 Aug 2017 05:48:36 -0700 (PDT) Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Wed, Aug 09, 2017 at 02:40:30PM CEST, jhs@mojatatu.com wrote: >On 17-08-07 07:21 PM, Cong Wang wrote: >> On Mon, Aug 7, 2017 at 12:54 PM, John Fastabend >> wrote: >> > On 08/07/2017 12:06 PM, Jiri Pirko wrote: >> > > Mon, Aug 07, 2017 at 07:47:14PM CEST, john.fastabend@gmail.com wrote: >> > > > On 08/07/2017 09:41 AM, Jiri Pirko wrote: >> > > > > Hi Jamal/Cong/David/all. >> > > > > >= >> > > >> > > Not correct. prio/pref is one level up priority, independent on specific >> > > cls implementation. You can have cls_u32 instance on prio 10 and >> > > cls_flower instance on prio 20. Both work. >> > >> > ah right, lets make sure I got this right then (its been awhile since I've >> > read this code). So the tcf_ctl_tfilter hook walks classifiers, inserting the >> > classifier by prio. Then tcf_classify walks the list of classifiers looking >> > for any matches, specifically any return codes it recognizes or a return code >> > greater than zero. u32 though has this link notion that allows users to jump >> > to other u32 classifiers that are in this list, because it has a global hash >> > table list. So the per prio classifier isolation is not true in u32 case. >> >> u32 filter supports multiple hash tables within a qdisc, struct >> tc_u_common is supposed to link them together. This has to be >> per qdisc because all of these hash tables belong to one qdisc >> and their ID's are unique within the qdisc. >> > >I think historically this used to sit within the u32 code as a >static linked list; i cant recall why it got attached to the >qdisc. >Indeed, the idea is that hash tables can be added independently >without linking and then linked afterwards. They have to be held >somewhere in transient. And they have priorities (at least the >prios are used in the dump) > >> I dislike it too, and I actually tried to improve it in the past, >> unfortunately didn't make any real progress. I think we can >> definitely make it less ugly, but I don't think we can totally >> get rid of it because of the design of u32. >> >> Similar for tp->data. >> > >tp->q maybe harder to deal with. I agree with getting rid of >this dependency. Could this info be stored in the block instead? Yeah, I will have to do that. I just wanted to get rid of it if possible :/ > >cheers, >jamal