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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 020B6C433EF for ; Sun, 3 Jul 2022 15:07:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232373AbiGCPHv (ORCPT ); Sun, 3 Jul 2022 11:07:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231145AbiGCPHu (ORCPT ); Sun, 3 Jul 2022 11:07:50 -0400 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C4205F67 for ; Sun, 3 Jul 2022 08:07:48 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R371e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0VIBrIff_1656860863; Received: from 30.0.187.160(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0VIBrIff_1656860863) by smtp.aliyun-inc.com; Sun, 03 Jul 2022 23:07:44 +0800 Message-ID: <68a5286b-7ff3-2c4e-1ab2-305e7860a2f3@linux.alibaba.com> Date: Sun, 3 Jul 2022 23:07:47 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [RFC PATCH v3 2/3] mm: Add PUD level pagetable account To: Matthew Wilcox Cc: Mike Rapoport , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <6a6a768634b9ce8537154264e35e6a66a79b6ca8.1656586863.git.baolin.wang@linux.alibaba.com> <1234a28a-dca0-5836-9066-4ab2d4fbcc95@linux.alibaba.com> <17df0d3c-caaf-ee34-f702-1d4e7674887f@linux.alibaba.com> From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/3/2022 10:52 PM, Matthew Wilcox wrote: > On Sun, Jul 03, 2022 at 10:06:32PM +0800, Baolin Wang wrote: >> So for kernel pte page table allocation, I need another similar helpers like >> below. However they do the samething with >> pgtable_pud_page_ctor/pgtable_pud_page_dtor, so I am not sure this is good >> for adding these duplicate code. > > Why do we want to account kernel PTE page tables in NR_PAGETABLE? > I think that's confusing. Why this will confuse you? I think it is inconsistent that kernel PTE page tables are not accounted, because we will account PMD/PUD level page tables no matter they are userspace pagetable pages or kernel pagetable pages. Moreover the the vmalloc()/vmap() can consume some kernel pagetable pages, which should be accounted.