From patchwork Mon Oct 24 08:34:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baolin Wang X-Patchwork-Id: 13016850 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C547DECDFA1 for ; Mon, 24 Oct 2022 08:34:37 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4BE218E0005; Mon, 24 Oct 2022 04:34:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 46EBE8E0002; Mon, 24 Oct 2022 04:34:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 384768E0005; Mon, 24 Oct 2022 04:34:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 2B5C28E0002 for ; Mon, 24 Oct 2022 04:34:37 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id E859340454 for ; Mon, 24 Oct 2022 08:34:36 +0000 (UTC) X-FDA: 80055181752.03.8C67C7F Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) by imf13.hostedemail.com (Postfix) with ESMTP id 1DCE320011 for ; Mon, 24 Oct 2022 08:34:34 +0000 (UTC) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R571e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0VSvcrBd_1666600470; Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VSvcrBd_1666600470) by smtp.aliyun-inc.com; Mon, 24 Oct 2022 16:34:31 +0800 From: Baolin Wang To: akpm@linux-foundation.org Cc: david@redhat.com, ying.huang@intel.com, ziy@nvidia.com, shy828301@gmail.com, apopple@nvidia.com, baolin.wang@linux.alibaba.com, jingshan@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/2] mm: migrate: Fix return value if all subpages of THPs are migrated successfully Date: Mon, 24 Oct 2022 16:34:21 +0800 Message-Id: X-Mailer: git-send-email 1.8.3.1 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666600476; a=rsa-sha256; cv=none; b=JJV6hhXmIYZ8UG9LMMUtIQZ51LtILrU9+L6VVpaZLObsUaKrBOnHl9DQ7vLxoj8PnnzZ08 7I8e/3ho2FDWXrUC13PNnxYtFKp7+8ZSnietIn2Zu2fROZtlnxp1FEGfimJuBtNM3/KuZt KAmJPaE3fYvOUMYZBK/e0UKQHTMl6W4= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf13.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.131 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666600476; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=KeC00WeoYZ/ViJPn20UQg+IEpDwRzEZ+DxYoDOeVhEM=; b=mf7dsP4fkYLuoHZuPxn6XJO3/vGPyNo/Ldy2Ou09r3qIYLN1CJLklTr5IBkhZaaWX5FtxN xOZIQ+4NYPIDYtXDcSNRepIa9iLGOXOlBQXMXLHSoKVuIP/zVtONt0vIAkOmRI9/cJhv00 Or44INcr7F0AuDq7c3HeGv+A7lnoKjs= Authentication-Results: imf13.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=alibaba.com; spf=pass (imf13.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.131 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: rm4ibh8kh7pp9igxh73socfei9cs3iay X-Rspamd-Queue-Id: 1DCE320011 X-HE-Tag: 1666600474-482681 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: During THP migration, if THPs are not migrated but they are split and all subpages are migrated successfully, migrate_pages() will still return the number of THP pages that were not migrated. This will confuse the callers of migrate_pages(). For example, the longterm pinning will failed though all pages are migrated successfully. Thus we should return 0 to indicate that all pages are migrated in this case Fixes: b5bade978e9b ("mm: migrate: fix the return value of migrate_pages()") Signed-off-by: Baolin Wang Reviewed-by: Alistair Popple Cc: Reviewed-by: Yang Shi --- Changes from v2: - Add Fixes tag suggested by Yang Shi and Huang, Ying. - Drop 'nr_thp_split' validation suggested by Alistair. - Add reviewed tag from Alistair. - Update the commit message suggested by Andrew. Changes from v1: - Fix the return value of migrate_pages() instead of fixing the callers' validation. --- mm/migrate.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 8e5eb6e..2eb16f8 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1582,6 +1582,13 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ list_splice(&ret_pages, from); + /* + * Return 0 in case all subpages of fail-to-migrate THPs are + * migrated successfully. + */ + if (list_empty(from)) + rc = 0; + count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); count_vm_events(PGMIGRATE_FAIL, nr_failed_pages); count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded);