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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 899E9C47082 for ; Wed, 26 May 2021 18:33:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5E0FE613E6 for ; Wed, 26 May 2021 18:33:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233227AbhEZSfE (ORCPT ); Wed, 26 May 2021 14:35:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:35752 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231189AbhEZSfC (ORCPT ); Wed, 26 May 2021 14:35:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4BBB3613BA; Wed, 26 May 2021 18:33:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622054011; bh=UK6wHJT4nW2m0M9S/InYlvnZnFEuXBK89A6fNGZIpBI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CCJ1YLsPawytssAl3Q5VhnAbUbV9uJbXaOEroICNKtpEqilp2LOzT8jY560tju94R DQU45Dah+XuW+9EZFeurk4JodvknKjTf6qW2qUC2bVjcbqs8cQxJD1XeHPmnEgcEm+ bSjM9DvjlTOafCHnThTpl/qWxsYSsZrcJGppItleu76zMj83WA6t/xpQqcG8cmSJP/ 29ikFBkdGV5zyzLHlXwe43xnkpO5Pyz1UMAXSH8K5grA+10HE7AHuVNaIyPnBFBJpb xUUk7iq4Df8ZMQmvvYz5u0IYxZM7Ur6N00fNjpnXL8/DpfXG+ZtjrYnJqE58+8ndem XGDWL7CFiLTkg== Date: Wed, 26 May 2021 19:33:23 +0100 From: Will Deacon To: Yury Norov Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Alexander Lobakin , Alexey Klimov , Andy Shevchenko , Anton Ivanov , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christian Borntraeger , Dan Williams , "H. Peter Anvin" , Heiko Carstens , Ingo Molnar , Jacob Keller , Jarkko Sakkinen , Jeff Dike , Kees Cook , Mark Brown , Matti Vaittinen , Nick Terrell , Palmer Dabbelt , Rasmus Villemoes , Richard Weinberger , Thomas Bogendoerfer , Thomas Gleixner , Vasily Gorbik , Vijayanand Jitta , Vineet Gupta , Yogesh Lal Subject: Re: [PATCH] all: remove GENERIC_FIND_FIRST_BIT Message-ID: <20210526183322.GB20055@willie-the-truck> References: <20210510233421.18684-1-yury.norov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210510233421.18684-1-yury.norov@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Mon, May 10, 2021 at 04:34:21PM -0700, Yury Norov wrote: > In the 5.12 cycle we enabled the GENERIC_FIND_FIRST_BIT config option > for ARM64 and MIPS. It increased performance and shrunk .text size; and > so far I didn't receive any negative feedback on the change. > > https://lore.kernel.org/linux-arch/20210225135700.1381396-1-yury.norov@gmail.com/ > > I think it's time to make all architectures use find_{first,last}_bit() > unconditionally and remove the corresponding config option. > > This patch doesn't introduce functional changes for arc, arm64, mips, > s390 and x86 because they already enable GENERIC_FIND_FIRST_BIT. There > will be no changes for arm because it implements find_{first,last}_bit > in arch code. For other architectures I expect improvement both in > performance and .text size. > > It would be great if people with an access to real hardware would share > the output of bloat-o-meter and lib/find_bit_benchmark. > > Signed-off-by: Yury Norov > --- > arch/arc/Kconfig | 1 - > arch/arm64/Kconfig | 1 - > arch/mips/Kconfig | 1 - > arch/s390/Kconfig | 1 - > arch/x86/Kconfig | 1 - > arch/x86/um/Kconfig | 1 - > include/asm-generic/bitops/find.h | 12 ------------ > lib/Kconfig | 3 --- > 8 files changed, 21 deletions(-) Acked-by: Will Deacon Will