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=-8.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY, 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 206BEECE560 for ; Fri, 14 Sep 2018 20:35:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D889520881 for ; Fri, 14 Sep 2018 20:35:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D889520881 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728257AbeIOBva (ORCPT ); Fri, 14 Sep 2018 21:51:30 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:48975 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727716AbeIOBva (ORCPT ); Fri, 14 Sep 2018 21:51:30 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04427;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0T8i4EXv_1536957308; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0T8i4EXv_1536957308) by smtp.aliyun-inc.com(127.0.0.1); Sat, 15 Sep 2018 04:35:16 +0800 From: Yang Shi To: mhocko@kernel.org, willy@infradead.org, ldufour@linux.vnet.ibm.com, vbabka@suse.cz, kirill@shutemov.name, akpm@linux-foundation.org Cc: dave.hansen@intel.com, oleg@redhat.com, srikar@linux.vnet.ibm.com, yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [RFC v10 PATCH 3/3] mm: unmap VM_PFNMAP mappings with optimized path Date: Sat, 15 Sep 2018 04:34:59 +0800 Message-Id: <1536957299-43536-4-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1536957299-43536-1-git-send-email-yang.shi@linux.alibaba.com> References: <1536957299-43536-1-git-send-email-yang.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When unmapping VM_PFNMAP mappings, vm flags need to be updated. Since the vmas have been detached, so it sounds safe to update vm flags with read mmap_sem. Cc: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Yang Shi --- mm/mmap.c | 9 --------- 1 file changed, 9 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 991e066..04c1d3b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2771,15 +2771,6 @@ static int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, munlock_vma_pages_all(tmp); } - /* - * Unmapping vmas, which have VM_HUGETLB or VM_PFNMAP, - * need get done with write mmap_sem held since they may - * update vm_flags. - */ - if (downgrade && - (tmp->vm_flags & VM_PFNMAP)) - downgrade = false; - tmp = tmp->vm_next; } } -- 1.8.3.1