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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 43867C33CAF for ; Thu, 16 Jan 2020 23:37:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07C7620661 for ; Thu, 16 Jan 2020 23:37:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579217864; bh=LNLkwqumuCRsUZzAEzSEPyLEs54KO1X1kXB8A1qAvQw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=VwOo6o4045RdE0+tcXPGl6aYRZ2yIC5sYCIVNUvP/k6pbgocNWbhrGBUMKioNPPYS ItMSOnVOLDRIHvjqTf0eoHjp2Ybm7LNVsxvyWTwW4ylKnep1bREccG6wOOpfNAw6px S+zCF4ZWEXhRsd3e0U/1P/71umL7kSUB1NTZ2bws= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391411AbgAPXhn (ORCPT ); Thu, 16 Jan 2020 18:37:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:50024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390085AbgAPXhg (ORCPT ); Thu, 16 Jan 2020 18:37:36 -0500 Received: from X1 (nat-ab2241.sltdut.senawave.net [162.218.216.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DC8AE2072B; Thu, 16 Jan 2020 23:37:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579217856; bh=LNLkwqumuCRsUZzAEzSEPyLEs54KO1X1kXB8A1qAvQw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XiJli2FduQhRgI8pXXx0H4Mh715uj9Rkkyyx6+ApiYXPlAB0n5ofBPOz8OI2HhrBN ZQONr0gbIy//k0a+OQVnS0X+Gz8xKuwbw1lhBCN1S0fr8Xf/c2jLKvab/e1zcdVUTT Eue2nsmA6xgn/tTSsHwXAQlqm2NaXo/VvouCw96Q= Date: Thu, 16 Jan 2020 15:37:35 -0800 From: Andrew Morton To: Qian Cai Cc: Alex Shi , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmscan: remove prefetch_prev_lru_page Message-Id: <20200116153735.3090629f3b40bd850c66bd18@linux-foundation.org> In-Reply-To: References: <739f4470-8dfe-bb2f-8100-2134f48868b6@linux.alibaba.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 16 Jan 2020 07:26:23 -0500 Qian Cai wrote: > > > > On Jan 14, 2020, at 9:33 PM, Alex Shi wrote: > > > >  > > > >> 在 2020/1/14 下午9:46, Qian Cai 写道: > >> > >> > >>>> On Jan 14, 2020, at 7:55 AM, Alex Shi wrote: > >>> > >>> This macro are never used in git history. So better to remove. > >> > >> When removing unused thingy, it is important to figure out which commit introduced it in the first place and Cc the relevant people in that commit. > >> > > > > Thanks fore reminder, Qian! > > > > This macro was introduced in 1da177e4c3f4 Linux-2.6.12-rc2, no author or commiter could be found. > > Looks a bit deeper for this, and I am not sure if it is necessary to remove it especially this does not cause any complication warning noise, because the macro looks like a part of API design to have a pair of both read and write version, even though only the write version is used at the moment. > > In theory, there could be users for the read version in the future, and then it needs to be added back. Sure. A problem with leaving it in place is that this leads people to assume it is tested, which it presumably is not. I don't think there's any particular downside either way, really. But it's presently cruft so I'm inclined to remove it. If someone has a need then they can add it back (presumbly reimplement it, actually) and test it then.