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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 9B039C63777 for ; Thu, 26 Nov 2020 06:39:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F333E20DD4 for ; Thu, 26 Nov 2020 06:39:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F333E20DD4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0EC906B006E; Thu, 26 Nov 2020 01:39:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F3FA26B0070; Thu, 26 Nov 2020 01:39:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E084B6B0071; Thu, 26 Nov 2020 01:39:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0032.hostedemail.com [216.40.44.32]) by kanga.kvack.org (Postfix) with ESMTP id C53536B006E for ; Thu, 26 Nov 2020 01:39:14 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 8DDE73631 for ; Thu, 26 Nov 2020 06:39:14 +0000 (UTC) X-FDA: 77525617428.16.value95_3805d362737d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 6F384100E690B for ; Thu, 26 Nov 2020 06:39:14 +0000 (UTC) X-HE-Tag: value95_3805d362737d X-Filterd-Recvd-Size: 2416 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Thu, 26 Nov 2020 06:39:12 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R761e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04423;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0UGZY9rf_1606372743; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UGZY9rf_1606372743) by smtp.aliyun-inc.com(127.0.0.1); Thu, 26 Nov 2020 14:39:03 +0800 Subject: Re: [PATCH next] mm/swap.c: reduce lock contention in lru_cache_add To: Yu Zhao Cc: Konstantin Khlebnikov , Andrew Morton , Hugh Dickins , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1605860847-47445-1-git-send-email-alex.shi@linux.alibaba.com> <20201126045234.GA1014081@google.com> From: Alex Shi Message-ID: Date: Thu, 26 Nov 2020 14:39:03 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201126045234.GA1014081@google.com> Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: =D4=DA 2020/11/26 =CF=C2=CE=E712:52, Yu Zhao =D0=B4=B5=C0: >> */ >> void __pagevec_lru_add(struct pagevec *pvec) >> { >> - int i; >> - struct lruvec *lruvec =3D NULL; >> + int i, nr_lruvec; >> unsigned long flags =3D 0; >> + struct page *page; >> + struct lruvecs lruvecs; >> =20 >> - for (i =3D 0; i < pagevec_count(pvec); i++) { >> - struct page *page =3D pvec->pages[i]; >> + nr_lruvec =3D sort_page_lruvec(&lruvecs, pvec); > Simply looping pvec multiple times (15 at most) for different lruvecs > would be better because 1) it requires no extra data structures and > therefore has better cache locality (theoretically faster) 2) it only > loops once when !CONFIG_MEMCG and !CONFIG_NUMA and therefore has no > impact on Android and Chrome OS. >=20 With multiple memcgs, it do help a lot, I had gotten 30% grain on readtwi= ce case. but yes, w/o MEMCG and NUMA, it's good to keep old behavior. So=20 would you like has a proposal for this? Thanks Alex