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=-5.5 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 90B98C433DF for ; Sat, 18 Jul 2020 14:03:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 58DD020684 for ; Sat, 18 Jul 2020 14:03:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 58DD020684 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 C84DF6B000A; Sat, 18 Jul 2020 10:03:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C0E536B000C; Sat, 18 Jul 2020 10:03:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD6B66B000D; Sat, 18 Jul 2020 10:03:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0227.hostedemail.com [216.40.44.227]) by kanga.kvack.org (Postfix) with ESMTP id 9329B6B000A for ; Sat, 18 Jul 2020 10:03:38 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1AF4318248DF1 for ; Sat, 18 Jul 2020 14:03:38 +0000 (UTC) X-FDA: 77051364516.17.pigs66_410aae626f14 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id DDBDE18249770 for ; Sat, 18 Jul 2020 14:01:54 +0000 (UTC) X-HE-Tag: pigs66_410aae626f14 X-Filterd-Recvd-Size: 4740 Received: from out30-54.freemail.mail.aliyun.com (out30-54.freemail.mail.aliyun.com [115.124.30.54]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Sat, 18 Jul 2020 14:01:53 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01422;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=20;SR=0;TI=SMTPD_---0U33ffAT_1595080903; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U33ffAT_1595080903) by smtp.aliyun-inc.com(127.0.0.1); Sat, 18 Jul 2020 22:01:44 +0800 Subject: Re: [PATCH v16 19/22] mm/lru: introduce the relock_page_lruvec function To: Alexander Duyck Cc: Andrew Morton , Mel Gorman , Tejun Heo , Hugh Dickins , Konstantin Khlebnikov , Daniel Jordan , Yang Shi , Matthew Wilcox , Johannes Weiner , kbuild test robot , linux-mm , LKML , cgroups@vger.kernel.org, Shakeel Butt , Joonsoo Kim , Wei Yang , "Kirill A. Shutemov" , Thomas Gleixner , Andrey Ryabinin References: <1594429136-20002-1-git-send-email-alex.shi@linux.alibaba.com> <1594429136-20002-20-git-send-email-alex.shi@linux.alibaba.com> From: Alex Shi Message-ID: <640e4081-3db3-c941-4b02-8a9aef26e7ba@linux.alibaba.com> Date: Sat, 18 Jul 2020 22:01:40 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 X-Rspamd-Queue-Id: DDBDE18249770 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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: =E5=9C=A8 2020/7/18 =E4=B8=8A=E5=8D=886:03, Alexander Duyck =E5=86=99=E9=81= =93: >> index 129c532357a4..9fb906fbaed5 100644 >> --- a/mm/swap.c >> +++ b/mm/swap.c >> @@ -209,19 +209,12 @@ static void pagevec_lru_move_fn(struct pagevec *= pvec, >> >> for (i =3D 0; i < pagevec_count(pvec); i++) { >> struct page *page =3D pvec->pages[i]; >> - struct lruvec *new_lruvec; >> - >> - new_lruvec =3D mem_cgroup_page_lruvec(page, page_pgdat= (page)); >> - if (lruvec !=3D new_lruvec) { >> - if (lruvec) >> - unlock_page_lruvec_irqrestore(lruvec, = flags); >> - lruvec =3D lock_page_lruvec_irqsave(page, &fla= gs); >> - } >> >> /* block memcg migration during page moving between lr= u */ >> if (!TestClearPageLRU(page)) >> continue; >> >> + lruvec =3D relock_page_lruvec_irqsave(page, lruvec, &f= lags); >> (*move_fn)(page, lruvec); >> >> SetPageLRU(page); > So looking at this I realize that patch 18 probably should have > ordered this the same way with the TestClearPageLRU happening before > you fetched the new_lruvec. Otherwise I think you are potentially > exposed to the original issue you were fixing the the previous patch > that added the call to TestClearPageLRU. Good catch. It's better to be aligned in next version. Thanks! >=20 >> @@ -866,17 +859,12 @@ void release_pages(struct page **pages, int nr) >> } >> >> if (PageLRU(page)) { >> - struct lruvec *new_lruvec; >> - >> - new_lruvec =3D mem_cgroup_page_lruvec(page, >> - page_pgdat(pag= e)); >> - if (new_lruvec !=3D lruvec) { >> - if (lruvec) >> - unlock_page_lruvec_irqrestore(= lruvec, >> - = flags); >> + struct lruvec *pre_lruvec =3D lruvec; >> + >> + lruvec =3D relock_page_lruvec_irqsave(page, lr= uvec, >> + = &flags); >> + if (pre_lruvec !=3D lruvec) > So this doesn't really read right. I suppose "pre_lruvec" should > probably be "prev_lruvec" since I assume you mean "previous" not > "before". yes, it's previous, I will rename it. Thanks Alex >=20