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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 B73CAC433E0 for ; Wed, 8 Jul 2020 09:51:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A007D20739 for ; Wed, 8 Jul 2020 09:51:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728537AbgGHJvB (ORCPT ); Wed, 8 Jul 2020 05:51:01 -0400 Received: from out4436.biz.mail.alibaba.com ([47.88.44.36]:15557 "EHLO out4436.biz.mail.alibaba.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728520AbgGHJvA (ORCPT ); Wed, 8 Jul 2020 05:51:00 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04427;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=15;SR=0;TI=SMTPD_---0U26MSrC_1594201844; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U26MSrC_1594201844) by smtp.aliyun-inc.com(127.0.0.1); Wed, 08 Jul 2020 17:50:44 +0800 From: Wei Yang To: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, vbabka@suse.cz, yang.shi@linux.alibaba.com, thomas_os@shipmail.org, anshuman.khandual@arm.com, sean.j.christopherson@intel.com, richard.weiyang@linux.alibaba.com, peterx@redhat.com, aneesh.kumar@linux.ibm.com, willy@infradead.org, thellstrom@vmware.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, digetx@gmail.com Subject: [Patch v4 2/4] mm/mremap: calculate extent in one place Date: Wed, 8 Jul 2020 17:50:26 +0800 Message-Id: <20200708095028.41706-3-richard.weiyang@linux.alibaba.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) In-Reply-To: <20200708095028.41706-1-richard.weiyang@linux.alibaba.com> References: <20200708095028.41706-1-richard.weiyang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Page tables is moved on the base of PMD. This requires both source and destination range should meet the requirement. Current code works well since move_huge_pmd() and move_normal_pmd() would check old_addr and new_addr again. And then return to move_ptes() if the either of them is not aligned. In stead of calculating the extent separately, it is better to calculate in one place, so we know it is not necessary to try move pmd. By doing so, the logic seems a little clear. Signed-off-by: Wei Yang Tested-by: Dmitry Osipenko Acked-by: Kirill A. Shutemov --- mm/mremap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index de27b12c8a5a..a30b3e86cc99 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -258,6 +258,9 @@ unsigned long move_page_tables(struct vm_area_struct *vma, extent = next - old_addr; if (extent > old_end - old_addr) extent = old_end - old_addr; + next = (new_addr + PMD_SIZE) & PMD_MASK; + if (extent > next - new_addr) + extent = next - new_addr; old_pmd = get_old_pmd(vma->vm_mm, old_addr); if (!old_pmd) continue; @@ -301,9 +304,6 @@ unsigned long move_page_tables(struct vm_area_struct *vma, if (pte_alloc(new_vma->vm_mm, new_pmd)) break; - next = (new_addr + PMD_SIZE) & PMD_MASK; - if (extent > next - new_addr) - extent = next - new_addr; move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma, new_pmd, new_addr, need_rmap_locks); } -- 2.20.1 (Apple Git-117)