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=-16.8 required=3.0 tests=BAYES_00, 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 14027C433B4 for ; Tue, 11 May 2021 13:49:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9EE9861363 for ; Tue, 11 May 2021 13:49:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9EE9861363 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7D8A26B0075; Tue, 11 May 2021 09:49:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 78B116B0078; Tue, 11 May 2021 09:49:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5DB8B8D0001; Tue, 11 May 2021 09:49:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id 3B1E66B0075 for ; Tue, 11 May 2021 09:49:21 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id F35CC9885 for ; Tue, 11 May 2021 13:49:20 +0000 (UTC) X-FDA: 78129082122.31.AF29BE6 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by imf20.hostedemail.com (Postfix) with ESMTP id 2A264D5 for ; Tue, 11 May 2021 13:49:20 +0000 (UTC) Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4FffMR285FzPwhY; Tue, 11 May 2021 21:45:55 +0800 (CST) Received: from huawei.com (10.175.104.170) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.498.0; Tue, 11 May 2021 21:49:06 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , , , , Subject: [PATCH v3 5/5] mm/huge_memory.c: don't discard hugepage if other processes are mapping it Date: Tue, 11 May 2021 21:48:57 +0800 Message-ID: <20210511134857.1581273-6-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210511134857.1581273-1-linmiaohe@huawei.com> References: <20210511134857.1581273-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.104.170] X-CFilter-Loop: Reflected Authentication-Results: imf20.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf20.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.191 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-Stat-Signature: micwoxxiwop1ptnqf4673re5mmo4ccrh X-Rspamd-Queue-Id: 2A264D5 X-Rspamd-Server: rspam02 Received-SPF: none (huawei.com>: No applicable sender policy available) receiver=imf20; identity=mailfrom; envelope-from=""; helo=szxga05-in.huawei.com; client-ip=45.249.212.191 X-HE-DKIM-Result: none/none X-HE-Tag: 1620740960-744982 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 other processes are mapping any other subpages of the hugepage, i.e. i= n pte-mapped thp case, page_mapcount() will return 1 incorrectly. Then we would discard the page while other processes are still mapping it. Fix it by using total_mapcount() which can tell whether other processes are stil= l mapping it. Fixes: b8d3c4c3009d ("mm/huge_memory.c: don't split THP page when MADV_FR= EE syscall is called") Reviewed-by: Yang Shi Signed-off-by: Miaohe Lin --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b8e67332806f..24647fe076b8 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1610,7 +1610,7 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, = struct vm_area_struct *vma, * If other processes are mapping this page, we couldn't discard * the page unless they all do MADV_FREE so let's skip the page. */ - if (page_mapcount(page) !=3D 1) + if (total_mapcount(page) !=3D 1) goto out; =20 if (!trylock_page(page)) --=20 2.23.0