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 719FCC433DF for ; Sat, 18 Jul 2020 14:02:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54B1F20684 for ; Sat, 18 Jul 2020 14:02:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727032AbgGROBy (ORCPT ); Sat, 18 Jul 2020 10:01:54 -0400 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:54981 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726611AbgGROBx (ORCPT ); Sat, 18 Jul 2020 10:01:53 -0400 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 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2020/7/18 上午6:03, Alexander Duyck 写道: >> 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 = 0; i < pagevec_count(pvec); i++) { >> struct page *page = pvec->pages[i]; >> - struct lruvec *new_lruvec; >> - >> - new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page)); >> - if (lruvec != new_lruvec) { >> - if (lruvec) >> - unlock_page_lruvec_irqrestore(lruvec, flags); >> - lruvec = lock_page_lruvec_irqsave(page, &flags); >> - } >> >> /* block memcg migration during page moving between lru */ >> if (!TestClearPageLRU(page)) >> continue; >> >> + lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags); >> (*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! > >> @@ -866,17 +859,12 @@ void release_pages(struct page **pages, int nr) >> } >> >> if (PageLRU(page)) { >> - struct lruvec *new_lruvec; >> - >> - new_lruvec = mem_cgroup_page_lruvec(page, >> - page_pgdat(page)); >> - if (new_lruvec != lruvec) { >> - if (lruvec) >> - unlock_page_lruvec_irqrestore(lruvec, >> - flags); >> + struct lruvec *pre_lruvec = lruvec; >> + >> + lruvec = relock_page_lruvec_irqsave(page, lruvec, >> + &flags); >> + if (pre_lruvec != 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 >