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 B7FA3CA5537 for ; Wed, 13 Sep 2023 09:52:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239484AbjIMJwM (ORCPT ); Wed, 13 Sep 2023 05:52:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239482AbjIMJwG (ORCPT ); Wed, 13 Sep 2023 05:52:06 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AB7819A9 for ; Wed, 13 Sep 2023 02:52:00 -0700 (PDT) Received: from dggpemm100001.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Rlwcb4nlyzNnRl; Wed, 13 Sep 2023 17:48:15 +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 17:51:58 +0800 From: Kefeng Wang To: Andrew Morton CC: , , , , , Zi Yan , Mike Kravetz , , Kefeng Wang Subject: [PATCH v3 1/8] mm: migrate: remove PageTransHuge check in numamigrate_isolate_page() Date: Wed, 13 Sep 2023 17:51:24 +0800 Message-ID: <20230913095131.2426871-2-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 The assert VM_BUG_ON_PAGE(order && !PageTransHuge(page), page) is not very useful, 1) for a tail/base page, order = 0, for a head page, the order > 0 && PageTransHuge() is true 2) there is a PageCompound() check and only base page is handled in do_numa_page(), and do_huge_pmd_numa_page() only handle PMD-mapped THP 3) even though the page is a tail page, isolate_lru_page() will post a warning, and fail to isolate the page 4) if large folio/pte-mapped THP migration supported in the future, we could migrate the entire folio if numa fault on a tail page so just remove the check. 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; -- 2.27.0