From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F281BC3815B for ; Mon, 20 Apr 2020 13:58:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2C6D20724 for ; Mon, 20 Apr 2020 13:58:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727817AbgDTN6F (ORCPT ); Mon, 20 Apr 2020 09:58:05 -0400 Received: from Chamillionaire.breakpoint.cc ([193.142.43.52]:33092 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726608AbgDTN6F (ORCPT ); Mon, 20 Apr 2020 09:58:05 -0400 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1jQWvq-0002GP-MT; Mon, 20 Apr 2020 15:57:54 +0200 Date: Mon, 20 Apr 2020 15:57:54 +0200 From: Florian Westphal To: Jiri Pirko Cc: Pablo Neira Ayuso , Edward Cree , netfilter-devel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: Re: [PATCH net] net: flow_offload: skip hw stats check for FLOW_ACTION_HW_STATS_DISABLED Message-ID: <20200420135754.GD32392@breakpoint.cc> References: <20200419115338.659487-1-pablo@netfilter.org> <20200420080200.GA6581@nanopsycho.orion> <20200420090505.pr6wsunozfh7afaj@salvia> <20200420091302.GB6581@nanopsycho.orion> <20200420100341.6qehcgz66wq4ysax@salvia> <20200420115210.GE6581@nanopsycho.orion> <3980eea4-18d8-5e62-2d6d-fce0a7e7ed4c@solarflare.com> <20200420123915.nrqancwjb7226l7e@salvia> <20200420134826.GH6581@nanopsycho.orion> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200420134826.GH6581@nanopsycho.orion> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jiri Pirko wrote: > Mon, Apr 20, 2020 at 02:39:15PM CEST, pablo@netfilter.org wrote: > >On Mon, Apr 20, 2020 at 01:28:22PM +0100, Edward Cree wrote: > >> On 20/04/2020 12:52, Jiri Pirko wrote: > >> > However for TC, when user specifies "HW_STATS_DISABLED", the driver > >> > should not do stats. > >> > >> What should a driver do if the user specifies DISABLED, but the stats > >>  are still needed for internal bookkeeping (e.g. to prod an ARP entry > >>  that's in use for encapsulation offload, so that it doesn't get > >>  expired out of the cache)?  Enable the stats on the HW anyway but > >>  not report them to FLOW_CLS_STATS?  Or return an error? > > > >My interpretation is that HW_STATS_DISABLED means that the front-end > >does not care / does not need counters. The driver can still allocate > > That is wrong interpretation. If user does not care, he specifies "ANY". > That is the default. > > When he says "DISABLED" he means disabled. Not "I don't care". Under what circumstances would the user care about this? Rejecting such config seems to be just to annoy user? I mean, the user is forced to use SW datapath just because HW can't turn off stats?! Same for a config change, why do i need to change my rules to say 'enable stats' even though I don't need them in first place? Unlike the inverse (want feature X but HW can't support it), it makes no sense to me to reject with an error here: stats-off is just a hint that can be safely ignored.