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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADD95C433EF for ; Thu, 10 Mar 2022 00:40:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3B9B68D0003; Wed, 9 Mar 2022 19:40:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3419B8D0001; Wed, 9 Mar 2022 19:40:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BBF38D0003; Wed, 9 Mar 2022 19:40:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0150.hostedemail.com [216.40.44.150]) by kanga.kvack.org (Postfix) with ESMTP id 0B81C8D0001 for ; Wed, 9 Mar 2022 19:40:39 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id CDD259F851 for ; Thu, 10 Mar 2022 00:40:37 +0000 (UTC) X-FDA: 79226620914.18.95F7316 Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) by imf27.hostedemail.com (Postfix) with ESMTP id 55A6240017 for ; Thu, 10 Mar 2022 00:40:37 +0000 (UTC) Received: by mail-pj1-f53.google.com with SMTP id k5-20020a17090a3cc500b001befa0d3102so5117044pjd.1 for ; Wed, 09 Mar 2022 16:40:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RzBwZmXuL2mtDGId2fRGQ9cdH48yHESLY1EUls+Y0mA=; b=3fblK4Lx9eyAfaGQJ50OJygXLr3+yngV/09AYMG9DMOQXco1UvGBl0AA0tGjTcpBuL qHt6ZCzQlf8sISB0V93pZihkUafr9czsnHqjVeIJB64e7Odk4gEDbBLGV7HMcnb4CNqe 2ZNlLK9eCP8cYoVJIeqOzgqErWYFpZzaGGpTl6YSYDkjL3SmiSahCh+xtHEDjO0njdJK 1yi1kqR3uM1lGNvzVBUU6G3FKCEUFo9CWrmmN/lwTOnG6fRdAzpVscQ6LsXIDFtDZ9nk 89nyYEbe1yTf8OUZXOg10LSsxznBJiSXMT/KFTyNyCSDq5UlCiSA4eUHry3XcY/oaIw4 Fcdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RzBwZmXuL2mtDGId2fRGQ9cdH48yHESLY1EUls+Y0mA=; b=ef9q1K2xTDJxnDfXk0wJyIXDKEPNHX+gcIsFjl2V5yn+N+E9btkQOeYQBS+2T4OY8N UCFudfWjGPDFchWb3GHipU0narRnrMMiA3vssSnd3JkxfiCuYcyw4DU2NDRQZzC/lISE 18APXS9VCRnMj8EzAEA7u2V7+mEKbmBDZH7xmuyqalvGe+jHGNJ02fDXDlcuVYTPcM1U 3vvEs2ZzlGR3cpeqhI8byI2mIMG60LAODb+9Tr92GFuBU6+92G/hlFZC+y21kB/klsW/ VBZ7nAfJIq9NNwHKxLebeFD6nYw+FRztWXvaW5b2HG/EEf6B88PGU7gsrg8SMsjagqwr Jx9A== X-Gm-Message-State: AOAM530FcS74q3Bdkc+jxWEupPEHQ0NX94xEWrQ0Cwx674WcK46mvO8P AnU2ElW0jgcg9Qr5chHby9BZ9RZ4TS+slHdtmYNZTA== X-Google-Smtp-Source: ABdhPJwFz17SQgb4pCOtnBdy5++/qwKC6LSIgtrRreuv2Nn2kEZn09A8yZqo+ZyLEO0m2rhpRcsK1XX++GWIEmAQt2U= X-Received: by 2002:a17:90a:990c:b0:1bc:3c9f:2abe with SMTP id b12-20020a17090a990c00b001bc3c9f2abemr2235610pjp.220.1646872836330; Wed, 09 Mar 2022 16:40:36 -0800 (PST) MIME-Version: 1.0 References: <20220302082718.32268-1-songmuchun@bytedance.com> <20220302082718.32268-4-songmuchun@bytedance.com> In-Reply-To: From: Dan Williams Date: Wed, 9 Mar 2022 16:40:25 -0800 Message-ID: Subject: Re: [PATCH v4 3/6] mm: rmap: introduce pfn_mkclean_range() to cleans PTEs To: Muchun Song Cc: Matthew Wilcox , Jan Kara , Al Viro , Andrew Morton , Alistair Popple , Yang Shi , Ralph Campbell , Hugh Dickins , xiyuyang19@fudan.edu.cn, "Kirill A. Shutemov" , Ross Zwisler , Christoph Hellwig , linux-fsdevel , Linux NVDIMM , Linux Kernel Mailing List , Linux MM , duanxiongchun@bytedance.com, Muchun Song Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 55A6240017 X-Stat-Signature: uns331sps3hy563ery7ipry1uz68t8mg Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=intel-com.20210112.gappssmtp.com header.s=20210112 header.b=3fblK4Lx; spf=none (imf27.hostedemail.com: domain of dan.j.williams@intel.com has no SPF policy when checking 209.85.216.53) smtp.mailfrom=dan.j.williams@intel.com; dmarc=fail reason="No valid SPF, DKIM not aligned (relaxed)" header.from=intel.com (policy=none) X-HE-Tag: 1646872837-144109 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: On Wed, Mar 9, 2022 at 4:26 PM Dan Williams wrote: > > On Wed, Mar 2, 2022 at 12:29 AM Muchun Song wrote: > > > > The page_mkclean_one() is supposed to be used with the pfn that has a > > associated struct page, but not all the pfns (e.g. DAX) have a struct > > page. Introduce a new function pfn_mkclean_range() to cleans the PTEs > > (including PMDs) mapped with range of pfns which has no struct page > > associated with them. This helper will be used by DAX device in the > > next patch to make pfns clean. > > This seems unfortunate given the desire to kill off > CONFIG_FS_DAX_LIMITED which is the only way to get DAX without 'struct > page'. > > I would special case these helpers behind CONFIG_FS_DAX_LIMITED such > that they can be deleted when that support is finally removed. ...unless this support is to be used for other PFN_MAP scenarios where a 'struct page' is not available? If so then the "(e.g. DAX)" should be clarified to those other cases.