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 BA733C77B72 for ; Fri, 14 Apr 2023 21:20:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229935AbjDNVUd (ORCPT ); Fri, 14 Apr 2023 17:20:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229704AbjDNVUc (ORCPT ); Fri, 14 Apr 2023 17:20:32 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5ECF194; Fri, 14 Apr 2023 14:20:31 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 66C6264A4A; Fri, 14 Apr 2023 21:20:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75EAEC433D2; Fri, 14 Apr 2023 21:20:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1681507230; bh=Nt5sAYDkqVFKgXOKuvGH+lBuk6l7+Tpahfx8XzQQnSg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nu67awMtPYdY1ih14Ofn1O9ZMWxIjP6jko3fZ1XP2mRJqN+3HX0qPFhKYXt9TyMJm b3QOxB55iFkR2l3rpftyTNBwFWFYJ6Cw0k9EIqNKUpJIXRx61zPoo5F+ub7YYlU13L huJV2f0QpTD13Y4ZrC2VFY+3k6Ozw/lEYEVhIycc= Date: Fri, 14 Apr 2023 14:20:29 -0700 From: Andrew Morton To: Eric Dumazet Cc: Yixin Shen , leon@kernel.org, davem@davemloft.net, linux-kernel@vger.kernel.org, ncardwell@google.com, netdev@vger.kernel.org, rdunlap@infradead.org Subject: Re: [PATCH net-next] lib/win_minmax: export symbol of minmax_running_min Message-Id: <20230414142029.6da5c1bfbf1da82cd0f1c085@linux-foundation.org> In-Reply-To: References: <20230413171918.GX17993@unreal> <20230414022736.63374-1-bobankhshen@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 14 Apr 2023 16:17:40 +0200 Eric Dumazet wrote: > On Fri, Apr 14, 2023 at 4:27 AM Yixin Shen wrote: > > > > > Please provide in-tree kernel user for that EXPORT_SYMBOL. > > > > It is hard to provide such an in-tree kernel user. We are trying to > > implement newer congestion control algorithms as dynamically loaded modules. > > For example, Copa(NSDI'18) which is adopted by Facebook needs to maintain > > such windowed min filters. Althought it is true that we can just > > copy-and-paste the code inside lib/win_minmax, it it more convenient to > > give the same status of minmax_running_min as minmax_running_max. > > It is confusing that only minmax_running_max is exported. > > This is needed by net/ipv4/tcp_bbr.c , which can be a module. > > > If this patch is rejected because the changes are too significant, > > Well, this path would soon be reverted by people using bots/tools to > detect unused functions, > or unused EXPORT symbols. > > So there is no point accepting it, before you submit the CC in the > official linux tree. It seems pretty darn screwy that we export minmax_running_max() but not minmax_running_min(). I'd be OK taking the patch just so we aren't pretty darn screwy. But it would be perfectly OK to include that one-liner within the patchset which adds a minmax_running_min() user.