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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C3D3C77B78 for ; Sat, 15 Apr 2023 08:31:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229786AbjDOIb3 (ORCPT ); Sat, 15 Apr 2023 04:31:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229574AbjDOIb1 (ORCPT ); Sat, 15 Apr 2023 04:31:27 -0400 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C6BC11FE7 for ; Sat, 15 Apr 2023 01:31:23 -0700 (PDT) Date: Sat, 15 Apr 2023 10:31:19 +0200 From: Pablo Neira Ayuso To: Jakub Kicinski Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, fw@strlen.de Subject: Re: [PATCH net-next 4/5] net: skbuff: push nf_trace down the bitfield Message-ID: References: <20230414160105.172125-1-kuba@kernel.org> <20230414160105.172125-5-kuba@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230414160105.172125-5-kuba@kernel.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Apr 14, 2023 at 09:01:04AM -0700, Jakub Kicinski wrote: > nf_trace is a debug feature, AFAIU, and yet it sits oddly > high in the sk_buff bitfield. Move it down, pushing up > dst_pending_confirm and inner_protocol_type. > > Next change will make nf_trace optional (under Kconfig) > and all optional fields should be placed after 2b fields > to avoid 2b fields straddling bytes. > > dst_pending_confirm is L3, so it makes sense next to ignore_df. > inner_protocol_type goes up just to keep the balance. Well, yes, this is indeed a debug feature. But if only one single container enables debugging, this cache line will be visited very often. The debugging infrastructure is guarded under a static_key, which is global.