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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D792CA5538 for ; Wed, 13 Sep 2023 09:52:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239588AbjIMJwU (ORCPT ); Wed, 13 Sep 2023 05:52:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239486AbjIMJwI (ORCPT ); Wed, 13 Sep 2023 05:52:08 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6272019BE for ; Wed, 13 Sep 2023 02:52:04 -0700 (PDT) Received: from dggpemm100001.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Rlwcy4tMkzMlLX; Wed, 13 Sep 2023 17:48:34 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by dggpemm100001.china.huawei.com (7.185.36.93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Wed, 13 Sep 2023 17:52:01 +0800 From: Kefeng Wang To: Andrew Morton CC: , , , , , Zi Yan , Mike Kravetz , , Kefeng Wang Subject: [PATCH v3 7/8] mm: migrate: remove PageHead() check for HugeTLB in add_page_for_migration() Date: Wed, 13 Sep 2023 17:51:30 +0800 Message-ID: <20230913095131.2426871-8-wangkefeng.wang@huawei.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20230913095131.2426871-1-wangkefeng.wang@huawei.com> References: <20230913095131.2426871-1-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm100001.china.huawei.com (7.185.36.93) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is some different between hugeTLB and THP behave when passed the address of a tail page, for THP, it will migrate the entire THP page, but for HugeTLB, it will return -EACCES, or -ENOENT before commit e66f17ff7177 ("mm/hugetlb: take page table lock in follow_huge_pmd()"), -EACCES The page is mapped by multiple processes and can be moved only if MPOL_MF_MOVE_ALL is specified. -ENOENT The page is not present. But when check manual[1], both of the two errnos are not suitable, it is better to keep the same behave between hugetlb and THP when passed the address of a tail page, so let's just remove the PageHead() check for HugeTLB. [1] https://man7.org/linux/man-pages/man2/move_pages.2.html Suggested-by: Mike Kravetz Acked-by: Zi Yan Signed-off-by: Kefeng Wang --- mm/migrate.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index cf5c9254fdad..7b07c97f5a6f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2093,10 +2093,8 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, goto out_putfolio; if (folio_test_hugetlb(folio)) { - if (PageHead(page)) { - isolated = isolate_hugetlb(folio, pagelist); - err = isolated ? 1 : -EBUSY; - } + isolated = isolate_hugetlb(folio, pagelist); + err = isolated ? 1 : -EBUSY; } else { isolated = folio_isolate_lru(folio); if (!isolated) { -- 2.27.0