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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 14263C433DB for ; Mon, 4 Jan 2021 07:01:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8E27E2087E for ; Mon, 4 Jan 2021 07:01:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E27E2087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bytedance.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B81C46B00A0; Mon, 4 Jan 2021 02:01:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B318D8D0002; Mon, 4 Jan 2021 02:01:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A210B8D0001; Mon, 4 Jan 2021 02:01:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0027.hostedemail.com [216.40.44.27]) by kanga.kvack.org (Postfix) with ESMTP id 88C426B00A0 for ; Mon, 4 Jan 2021 02:01:15 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 41314824805A for ; Mon, 4 Jan 2021 07:01:15 +0000 (UTC) X-FDA: 77667196110.01.jail32_060edac274ce Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id 24BF41004764C for ; Mon, 4 Jan 2021 07:01:15 +0000 (UTC) X-HE-Tag: jail32_060edac274ce X-Filterd-Recvd-Size: 3737 Received: from mail-pj1-f42.google.com (mail-pj1-f42.google.com [209.85.216.42]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Mon, 4 Jan 2021 07:01:14 +0000 (UTC) Received: by mail-pj1-f42.google.com with SMTP id iq13so9461282pjb.3 for ; Sun, 03 Jan 2021 23:01:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=KfWnBt9oMWkYekWPdC8T/NbKzeZ/tVaqKYGZLAFF0lk=; b=XnrcvtLGW3NnmKsqgZ99vjzAVDjrRuk7oMv+sz+YCA19t+irHF982MYUr3KSKp3/Cd KgZnj0IAKDQnVPHC2tiQHJGHTadqblujYH4Q5KMhq6meBiKVCfod9fKE/j2BaXZ9Vaj0 r0/lFIln/I+0uRa2SUhr2oN692OsEe3ElgM6thaJQGJk8SjC44XCHr1lWbCi0P1mOLm+ bdjP74QFrbcxTJoA60I4BaMYZBs7y83siX8r/7OO5XMEdUmFm6WmaYx7T9gr793fV3aO wZFKORYiFB5oGansXHiLmsourUDqryOD3eeB4ZFszlN3U1lzBwnNSs8aWmr/VCPCrDin DNSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=KfWnBt9oMWkYekWPdC8T/NbKzeZ/tVaqKYGZLAFF0lk=; b=lxA1YbEttcVKEDWADzwzU8WGpG+4bPVmgtySltQN5q02kMFWrq3yH4hm7XPuRkCg6A 5PgsxrcAQmI/0jXz+MmfTlTEPRufeNiw/bjHiDs0iLxsLCfaTCYkIAVSx8JNsowSLF8v nBw/Dy7vaPK0wR4oZA1muaEobN09pUD/+n+IrjT7gxFPFCjl5BK9lD80OvaoNdxiVqkH GCcSjwu+g5Y66VDZn/L3WtH961Ltk+j4HWi12AEkKO/9UHo6VKmQAd7X9qE/fiZ1oXW4 jm8ThQm7IBLUhflb77CMOeg65511Gla0dUcL1RKmQg/35+rODiVEgoNj2CqtaIc8tr/B 2scg== X-Gm-Message-State: AOAM533MlKQAcLBQqodHCZU+t+CJuQsUxLlB2jKrZse4kJiJdDoS/KAk W0W53WmEDaT0gBZ64NpvEaE/6w== X-Google-Smtp-Source: ABdhPJwefBRpU311LeHDKfh1oqafHOF8ar7PhHcu5bep1BOfGProsLsWyVlvDYGkE6kgdWnVTM/1jA== X-Received: by 2002:a17:90b:2317:: with SMTP id mt23mr28669952pjb.2.1609743673362; Sun, 03 Jan 2021 23:01:13 -0800 (PST) Received: from localhost.localdomain ([240e:b1:e401:3::6]) by smtp.gmail.com with ESMTPSA id v1sm36306648pga.63.2021.01.03.23.00.41 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 03 Jan 2021 23:01:12 -0800 (PST) From: Muchun Song To: mike.kravetz@oracle.com, akpm@linux-foundation.org Cc: hillf.zj@alibaba-inc.com, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, yongjun_wei@trendmicro.com.cn, mhocko@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song Subject: [PATCH 1/6] mm: migrate: do not migrate HugeTLB page whose refcount is one Date: Mon, 4 Jan 2021 14:58:38 +0800 Message-Id: <20210104065843.5658-1-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) MIME-Version: 1.0 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: 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; } =20 + if (page_count(hpage) =3D=3D 1) { + /* page was freed from under us. So we are done. */ + putback_active_hugepage(hpage); + return MIGRATEPAGE_SUCCESS; + } + new_hpage =3D get_new_page(hpage, private); if (!new_hpage) return -ENOMEM; --=20 2.11.0