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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 E3603C4360F for ; Thu, 7 Mar 2019 17:46:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF56E20851 for ; Thu, 7 Mar 2019 17:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726307AbfCGRqF (ORCPT ); Thu, 7 Mar 2019 12:46:05 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:52252 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726766AbfCGRqB (ORCPT ); Thu, 7 Mar 2019 12:46:01 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id DE70F1479C61D; Thu, 7 Mar 2019 09:46:00 -0800 (PST) Date: Thu, 07 Mar 2019 09:46:00 -0800 (PST) Message-Id: <20190307.094600.334828809875646248.davem@davemloft.net> To: arnd@arndb.de Cc: f.fainelli@gmail.com, jakub.kicinski@netronome.com, jiri@mellanox.com, wang6495@umn.edu, mkubecek@suse.cz, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [v2] ethtool: reduce stack usage with clang From: David Miller In-Reply-To: <20190307160017.3120362-1-arnd@arndb.de> References: <20190307160017.3120362-1-arnd@arndb.de> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 07 Mar 2019 09:46:01 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Arnd Bergmann Date: Thu, 7 Mar 2019 16:58:35 +0100 > clang inlines the dev_ethtool() more aggressively than gcc does, leading > to a larger amount of used stack space: > > net/core/ethtool.c:2536:24: error: stack frame size of 1216 bytes in function 'dev_ethtool' [-Werror,-Wframe-larger-than=] > > Marking the sub-functions that require the most stack space as > noinline_for_stack gives us reasonable behavior on all compilers. > > Signed-off-by: Arnd Bergmann > --- > v2: don't annotate dev_ethtool itself, as pointed out by Michal Kubecek I'll apply this, but as Michal said this is just papering over the problem, the aggregate stack allocation is still the same and very large.