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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 3CE8CC11F69 for ; Thu, 1 Jul 2021 01:48:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E5B9D61090 for ; Thu, 1 Jul 2021 01:47:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5B9D61090 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6E0AD8D01E3; Wed, 30 Jun 2021 21:47:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 690528D01D0; Wed, 30 Jun 2021 21:47:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 531258D01E3; Wed, 30 Jun 2021 21:47:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0134.hostedemail.com [216.40.44.134]) by kanga.kvack.org (Postfix) with ESMTP id 28DC38D01D0 for ; Wed, 30 Jun 2021 21:47:59 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 056FF25F5A for ; Thu, 1 Jul 2021 01:47:59 +0000 (UTC) X-FDA: 78312333078.31.736F9FC Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf30.hostedemail.com (Postfix) with ESMTP id AD3AFE003050 for ; Thu, 1 Jul 2021 01:47:58 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 5ED9061468; Thu, 1 Jul 2021 01:47:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1625104078; bh=CWbtpEeKSCBvywFsbct1J9BSrRL6Ri6SyG74X8TBURA=; h=Date:From:To:Subject:In-Reply-To:From; b=Zsf4cdI376IqMUe4nNxrjAyWoDIu3BwiRBNCkl+8f9addegcFSAQAacClf3l4Tjrv oeTS6qWA3rfRcd9YQx9D3AsbbrBLKNnn44aIBgP1kGSvoLcLbY+1bh3Ak0Aic7ytww iP4c327T11qq3v4N1yZ4j1h1dqjgncBAQ1lpAIQs= Date: Wed, 30 Jun 2021 18:47:57 -0700 From: Andrew Morton To: adobriyan@gmail.com, akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, anshuman.khandual@arm.com, david@redhat.com, hannes@cmpxchg.org, hughd@google.com, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, linux-mm@kvack.org, mike.kravetz@oracle.com, minchan@kernel.org, mm-commits@vger.kernel.org, rcampbell@nvidia.com, riel@surriel.com, shy828301@gmail.com, songliubraving@fb.com, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, ziy@nvidia.com Subject: [patch 016/192] mm/huge_memory.c: don't discard hugepage if other processes are mapping it Message-ID: <20210701014757.SdeAPP5pY%akpm@linux-foundation.org> In-Reply-To: <20210630184624.9ca1937310b0dd5ce66b30e7@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=Zsf4cdI3; spf=pass (imf30.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Stat-Signature: 8hpd67d9hhf3djouu6jkptg4omif15yk X-Rspamd-Queue-Id: AD3AFE003050 X-Rspamd-Server: rspam06 X-HE-Tag: 1625104078-978107 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: From: Miaohe Lin Subject: mm/huge_memory.c: don't discard hugepage if other processes are mapping it If other processes are mapping any other subpages of the hugepage, i.e. in 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 still mapping it. Link: https://lkml.kernel.org/r/20210511134857.1581273-6-linmiaohe@huawei.com Fixes: b8d3c4c3009d ("mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called") Reviewed-by: Yang Shi Signed-off-by: Miaohe Lin Cc: Alexey Dobriyan Cc: "Aneesh Kumar K . V" Cc: Anshuman Khandual Cc: David Hildenbrand Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kirill A. Shutemov Cc: Matthew Wilcox Cc: Minchan Kim Cc: Ralph Campbell Cc: Rik van Riel Cc: Song Liu Cc: William Kucharski Cc: Zi Yan Cc: Mike Kravetz Signed-off-by: Andrew Morton --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/huge_memory.c~mm-huge_memoryc-dont-discard-hugepage-if-other-processes-are-mapping-it +++ a/mm/huge_memory.c @@ -1613,7 +1613,7 @@ bool madvise_free_huge_pmd(struct mmu_ga * 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) != 1) + if (total_mapcount(page) != 1) goto out; if (!trylock_page(page)) _