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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 AA792C433DB for ; Tue, 5 Jan 2021 18:05:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3F6B922CF7 for ; Tue, 5 Jan 2021 18:05:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F6B922CF7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BB7E58D008C; Tue, 5 Jan 2021 13:04:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B66158D006E; Tue, 5 Jan 2021 13:04:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A54758D008C; Tue, 5 Jan 2021 13:04:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0226.hostedemail.com [216.40.44.226]) by kanga.kvack.org (Postfix) with ESMTP id 8974D8D006E for ; Tue, 5 Jan 2021 13:04:59 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 521711EF3 for ; Tue, 5 Jan 2021 18:04:59 +0000 (UTC) X-FDA: 77672497518.29.dolls26_3217b4e274da Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 2C55218086CA8 for ; Tue, 5 Jan 2021 18:04:59 +0000 (UTC) X-HE-Tag: dolls26_3217b4e274da X-Filterd-Recvd-Size: 3872 Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Tue, 5 Jan 2021 18:04:58 +0000 (UTC) Received: by mail-ed1-f44.google.com with SMTP id cw27so1562840edb.5 for ; Tue, 05 Jan 2021 10:04:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=8XDnRNruv1BMN32pgPpm0wYF2+zLKqENUZJC1YcQG8E=; b=UMmnZ7onPSCcBs/9pq3qdK0GKHAyO+Sslt6oiVhPTtbpSmnsvh1uwAkd81ohspRKrY E8nBzprH+kCMQarh7Tk+smtUsZqJ7rYkpmN8hUsfwnnrCY+h8WJeJy+q/9S4EMo/nItA 5tB0f+6sktCE1+N6Akse8qaRQdyf4URe+uoB/Dmei6HSX+ofZYR7079IE4KC3C/dzk0p /ZGLCNmL0ooYEWw8OaC72La+EMudidWjXATKfOi94Txolpr4bSJksHv7RxJ8IVpzPUs4 EU6MYyqU+SDuCnUlnsYKF9ADMAGbqv4MEbcdZVvOsvCaRIOpllpV3cXE1OlTc6S2xpu/ 0XOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=8XDnRNruv1BMN32pgPpm0wYF2+zLKqENUZJC1YcQG8E=; b=HktCXInQfic/bkXwUNHM5vanL0jx1oE0eYdUZ7b5fRxa+r1YfrAadq2zIGXzwWDijQ M+iK47o6rc13UP6fRs6iQKaPnprgEYDkixkpSfYcZaaJhXB8GKYpH98eEha2npyVnkwI 5347MSyfbTbtzZdseTYLWMNv8t6gKZDqGeGczehnP180eK8A3YPdDslN3MtiVvDqYLoW 6uFhebXLx4QG6VYUe1mDCAVCfBPSvaIUJ4E83opliBUk6c3a8SLTYqFZZICFHf9ZqSPK ERAEzjEv9/TLwSbjsq9M5ceoU44vdgBn9qUHhRkHW7EQQ4t+7gEFc5/fJUmxfbiwBSw/ COvA== X-Gm-Message-State: AOAM532DYduucuKuJavWlY6UAvh07EvdrqXT2uj4pnrYyUNPpSdXQ36P JjkLKJmFb4h+N0ejrqRaqSiXSWkHek0uYgFyIV4= X-Google-Smtp-Source: ABdhPJx+L930FDjLcQS1ibgZAJNKrpVQt6flaJ6sFWwBPA8TLp5Vkh+bzsAAQzJrLnTl5xc+J4b460PrAVLDVpN7nEw= X-Received: by 2002:a05:6402:746:: with SMTP id p6mr950652edy.313.1609869897809; Tue, 05 Jan 2021 10:04:57 -0800 (PST) MIME-Version: 1.0 References: <20210104065843.5658-1-songmuchun@bytedance.com> In-Reply-To: <20210104065843.5658-1-songmuchun@bytedance.com> From: Yang Shi Date: Tue, 5 Jan 2021 10:04:44 -0800 Message-ID: Subject: Re: [PATCH 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one To: Muchun Song Cc: Mike Kravetz , Andrew Morton , hillf.zj@alibaba-inc.com, Naoya Horiguchi , ak@linux.intel.com, yongjun_wei@trendmicro.com.cn, mhocko@suse.cz, Linux MM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" 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 Sun, Jan 3, 2021 at 11:01 PM Muchun Song wrote: > > If the refcount is one when it is migrated, it means that the page > was freed from under us. So we are done and do not need to migrate. > > Signed-off-by: Muchun Song > --- > mm/migrate.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/migrate.c b/mm/migrate.c > index 4385f2fb5d18..a6631c4eb6a6 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1279,6 +1279,12 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, > return -ENOSYS; > } > > + if (page_count(hpage) == 1) { > + /* page was freed from under us. So we are done. */ > + putback_active_hugepage(hpage); > + return MIGRATEPAGE_SUCCESS; > + } > + Acked-by: Yang Shi > new_hpage = get_new_page(hpage, private); > if (!new_hpage) > return -ENOMEM; > -- > 2.11.0 > >