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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBE0EC433F5 for ; Mon, 7 Mar 2022 07:02:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5969D8D0003; Mon, 7 Mar 2022 02:02:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 51F098D0001; Mon, 7 Mar 2022 02:02:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E7178D0003; Mon, 7 Mar 2022 02:02:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0095.hostedemail.com [216.40.44.95]) by kanga.kvack.org (Postfix) with ESMTP id 30AE08D0001 for ; Mon, 7 Mar 2022 02:02:55 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id EB07D182C9D89 for ; Mon, 7 Mar 2022 07:02:54 +0000 (UTC) X-FDA: 79216697868.25.E70410A Received: from mail-yw1-f175.google.com (mail-yw1-f175.google.com [209.85.128.175]) by imf04.hostedemail.com (Postfix) with ESMTP id BB36040009 for ; Mon, 7 Mar 2022 07:02:53 +0000 (UTC) Received: by mail-yw1-f175.google.com with SMTP id 00721157ae682-2dc28791ecbso138931417b3.4 for ; Sun, 06 Mar 2022 23:02:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=geOY0BIdj9dQeQr7DqDH3p1hC5fsVdyguZbly+zPwEA=; b=eoKBFkv0FaSw/htLzF49O05SJL61SrM2q6muI4X/eTCvVopJwjVnZy/U6ieybXM2yS cgAubMZzSziznc4i6TrZSbZq1vhhRi6NyTLgn3s7NGmMRDqE5jyuYrxleF1bz2UuxhTA zxwnLHHecgF/150OvTd6MONyyWMGYOJEw8wnXC/daertskkGHEqorUfOlHxri3ZQhmkI bc2oDsJpzKVkBRkJU1YBKjncfbAcEKguvIUs6mnQNUWSUzRQySaOy64Mx7JGC0egtyQ7 Rg13CPlGODHwEJQJWa61iHITNjjMtMWPbXbNCHj1B3HLezJlqw1HDGPhn9yjMGaGQ/OV AHmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=geOY0BIdj9dQeQr7DqDH3p1hC5fsVdyguZbly+zPwEA=; b=LCt77r4RICCMeYlVdKUpfbSb/R+S4bPg3y22KKfjblnAMeyyBQibIqWTQF/Cf55QTq Cbuc9n6mp1TgWpVJHMEK4UdWmVk4sMGHgJNQwj3RfufCB0mD6KOmzb4NuGJ0YzUYfUrs NG4RrCk/Et+q6YhvVbspju62NdyZLYfaLYSHw/hyJXV+lCMNdxt8qbpUuymhd8mjeWNs vH+brllD2bJBq7h48iqSY7flYA/OXFHLgXfVVOxGz3cYMMeppXfuaQGwTDhpPYWqaRpg iCgOuI2PU9gOBUv6rkNi77oKDPKT6ZA0/6+8HSf9tjVo2ObycqUzi637NCCwcaOusAbj dOMA== X-Gm-Message-State: AOAM531AOgUPb04/7amMwPsximK5D7ZvX9PAciQLYSo/oM/LOu3VHfUo RPSOdHDQ7AkeMSooSjQOhPSqwPdyM8gC+WHqIIpU+Q== X-Google-Smtp-Source: ABdhPJyY0qfIRpVo0WQFwnKf7xkXXwTlFOCupODWGFK0/ryR8UoK13fwckAiCay7cW3UMCqPiVTVg510FSrE7UVS4f4= X-Received: by 2002:a0d:cec2:0:b0:2dc:a4d3:4528 with SMTP id q185-20020a0dcec2000000b002dca4d34528mr5361083ywd.35.1646636572768; Sun, 06 Mar 2022 23:02:52 -0800 (PST) MIME-Version: 1.0 References: <20220304093409.25829-1-linmiaohe@huawei.com> <20220304093409.25829-16-linmiaohe@huawei.com> <875yoq5od4.fsf@yhuang6-desk2.ccr.corp.intel.com> In-Reply-To: <875yoq5od4.fsf@yhuang6-desk2.ccr.corp.intel.com> From: Muchun Song Date: Mon, 7 Mar 2022 15:01:12 +0800 Message-ID: Subject: Re: [PATCH 15/16] mm/migration: fix possible do_pages_stat_array racing with memory offline To: "Huang, Ying" Cc: Miaohe Lin , Andrew Morton , Mike Kravetz , Yang Shi , Matthew Wilcox , Zi Yan , Minchan Kim , Alistair Popple , ave.hansen@linux.intel.com, o451686892@gmail.com, Mina Almasry , John Hubbard , Ralph Campbell , Peter Xu , =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= , Michal Hocko , riel@redhat.com, Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: BB36040009 X-Stat-Signature: xrebzcpcawr6zc8dircfp175tpkubfwp X-Rspam-User: Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=eoKBFkv0; spf=pass (imf04.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.128.175 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-Rspamd-Server: rspam07 X-HE-Tag: 1646636573-76744 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: On Mon, Mar 7, 2022 at 1:22 PM Huang, Ying wrote: > > Miaohe Lin writes: > > > When follow_page peeks a page, the page could be reclaimed under heavy > > memory pressure > > I don't think that memory pressure and reclaiming will be an issue. I think he means a page first to be reclaimed then to be offline could encounter this issue and reclaiming is a precondition. Thanks. > > > and thus be offlined while it's still being used by the > > do_pages_stat_array(). > > "offline" seems a possible problem.