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=-2.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 5C57CECDFC0 for ; Tue, 11 Sep 2018 20:58:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC48F206B7 for ; Tue, 11 Sep 2018 20:58:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC48F206B7 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 S1728046AbeILB7y (ORCPT ); Tue, 11 Sep 2018 21:59:54 -0400 Received: from out30-133.freemail.mail.aliyun.com ([115.124.30.133]:43576 "EHLO out30-133.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726850AbeILB7x (ORCPT ); Tue, 11 Sep 2018 21:59:53 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01451;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0T8Sg6Yy_1536699501; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0T8Sg6Yy_1536699501) by smtp.aliyun-inc.com(127.0.0.1); Wed, 12 Sep 2018 04:58:30 +0800 From: Yang Shi To: mhocko@kernel.org, willy@infradead.org, ldufour@linux.vnet.ibm.com, vbabka@suse.cz, akpm@linux-foundation.org, dave.hansen@intel.com, oleg@redhat.com, srikar@linux.vnet.ibm.com Cc: yang.shi@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [RFC v9 PATCH 3/4] mm: unmap VM_HUGETLB mappings with optimized path Date: Wed, 12 Sep 2018 04:58:12 +0800 Message-Id: <1536699493-69195-4-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1536699493-69195-1-git-send-email-yang.shi@linux.alibaba.com> References: <1536699493-69195-1-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_HUGETLB 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 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 937d2f2..086f8b5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2812,12 +2812,12 @@ static int do_munmap_zap_rlock(struct mm_struct *mm, unsigned long start, } /* - * Unmapping vmas, which have VM_HUGETLB or VM_PFNMAP + * Unmapping vmas, which have VM_PFNMAP * need get done with write mmap_sem held since they may update * vm_flags. Deal with such mappings with regular do_munmap() call. */ for (vma = start_vma; vma && vma->vm_start < end; vma = vma->vm_next) { - if (vma->vm_flags & (VM_HUGETLB | VM_PFNMAP)) + if (vma->vm_flags & VM_PFNMAP) goto regular_path; } -- 1.8.3.1