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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 062A7C33CB3 for ; Thu, 16 Jan 2020 23:37:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A0B9E2073A for ; Thu, 16 Jan 2020 23:37:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="XiJli2Fd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A0B9E2073A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 190498E0094; Thu, 16 Jan 2020 18:37:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 140858E0089; Thu, 16 Jan 2020 18:37:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 05E438E0094; Thu, 16 Jan 2020 18:37:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0136.hostedemail.com [216.40.44.136]) by kanga.kvack.org (Postfix) with ESMTP id DFA9A8E0089 for ; Thu, 16 Jan 2020 18:37:37 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 74CAE2494 for ; Thu, 16 Jan 2020 23:37:37 +0000 (UTC) X-FDA: 76385111754.13.river64_7cb5cd7e92c03 X-HE-Tag: river64_7cb5cd7e92c03 X-Filterd-Recvd-Size: 3016 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Thu, 16 Jan 2020 23:37:36 +0000 (UTC) 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: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.006936, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 16 Jan 2020 07:26:23 -0500 Qian Cai wrote: >=20 >=20 > > On Jan 14, 2020, at 9:33 PM, Alex Shi wr= ote: > >=20 > > =EF=BB=BF > >=20 > >> =E5=9C=A8 2020/1/14 =E4=B8=8B=E5=8D=889:46, Qian Cai =E5=86=99=E9=81= =93: > >>=20 > >>=20 > >>>> On Jan 14, 2020, at 7:55 AM, Alex Shi = wrote: > >>>=20 > >>> This macro are never used in git history. So better to remove. > >>=20 > >> When removing unused thingy, it is important to figure out which com= mit introduced it in the first place and Cc the relevant people in that c= ommit. > >>=20 > >=20 > > Thanks fore reminder, Qian! > >=20 > > This macro was introduced in 1da177e4c3f4 Linux-2.6.12-rc2, no author= or commiter could be found. >=20 > Looks a bit deeper for this, and I am not sure if it is necessary to re= move it especially this does not cause any complication warning noise, be= cause the macro looks like a part of API design to have a pair of both re= ad and write version, even though only the write version is used at the m= oment. >=20 > In theory, there could be users for the read version in the future, an= d 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.