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 7F85AEE4996 for ; Mon, 21 Aug 2023 14:41:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236038AbjHUOl3 (ORCPT ); Mon, 21 Aug 2023 10:41:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45432 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232388AbjHUOl2 (ORCPT ); Mon, 21 Aug 2023 10:41:28 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAE40E8 for ; Mon, 21 Aug 2023 07:41:24 -0700 (PDT) Received: from dggpemm100001.china.huawei.com (unknown [172.30.72.54]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4RTw7v1BZ2zLp2r; Mon, 21 Aug 2023 22:38:19 +0800 (CST) Received: from [10.174.177.243] (10.174.177.243) 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; Mon, 21 Aug 2023 22:41:21 +0800 Message-ID: Date: Mon, 21 Aug 2023 22:41:21 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/8] mm: migrate: remove PageTransHuge check in numamigrate_isolate_page() Content-Language: en-US From: Kefeng Wang To: Matthew Wilcox CC: Andrew Morton , , , , , Zi Yan , Mike Kravetz , References: <20230821115624.158759-1-wangkefeng.wang@huawei.com> <20230821115624.158759-2-wangkefeng.wang@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) 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 On 2023/8/21 20:52, Kefeng Wang wrote: > > > On 2023/8/21 20:38, Matthew Wilcox wrote: >> On Mon, Aug 21, 2023 at 07:56:17PM +0800, Kefeng Wang wrote: >>> Since we begin to convert the numa migration code to use folio, which >>> could let us to handle arbitrary sizes of folio, so drop assert that >>> we only support PageTransHuge page(PMD size) when order > 0. >> >> Have you looked at the implementation of PageTransHuge()?  Your >> description doesn't match what the code does. > > oops, not only PMD size... Please ignore about reply, sorry，I misread， PageTransHuge return true for head page, and BUG_ON for tail page, and compound_order(page) will return 0 for tail page, so when begin to convert page to folio, we could drop this line since it is not useful check for folio. > >> >>> Suggested-by: Matthew Wilcox (Oracle) >>> Signed-off-by: Kefeng Wang >>> --- >>>   mm/migrate.c | 2 -- >>>   1 file changed, 2 deletions(-) >>> >>> diff --git a/mm/migrate.c b/mm/migrate.c >>> index b7fa020003f3..646d8ee7f102 100644 >>> --- a/mm/migrate.c >>> +++ b/mm/migrate.c >>> @@ -2483,8 +2483,6 @@ static int numamigrate_isolate_page(pg_data_t >>> *pgdat, struct page *page) >>>       int nr_pages = thp_nr_pages(page); >>>       int order = compound_order(page); >>> -    VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); >>> - >>>       /* Do not migrate THP mapped by multiple processes */ >>>       if (PageTransHuge(page) && total_mapcount(page) > 1) >>>           return 0; >>> -- >>> 2.41.0 >>> >>> >>