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 150FFC433EF for ; Fri, 21 Jan 2022 08:34:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 97F5C6B007E; Fri, 21 Jan 2022 03:34:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 92ED56B0080; Fri, 21 Jan 2022 03:34:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 844996B0081; Fri, 21 Jan 2022 03:34:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0090.hostedemail.com [216.40.44.90]) by kanga.kvack.org (Postfix) with ESMTP id 714DC6B007E for ; Fri, 21 Jan 2022 03:34:24 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 2EBEE8B30B for ; Fri, 21 Jan 2022 08:34:24 +0000 (UTC) X-FDA: 79053632448.28.EC4C33B Received: from heian.cn.fujitsu.com (mail.cn.fujitsu.com [183.91.158.132]) by imf20.hostedemail.com (Postfix) with ESMTP id 38E0F1C0005 for ; Fri, 21 Jan 2022 08:34:22 +0000 (UTC) IronPort-Data: =?us-ascii?q?A9a23=3ATGEFKqh5CkSoF7MEZqgz4YuZX161CxEKZh0ujC4?= =?us-ascii?q?5NGQNrF6WrkUAy2YXUD+ObvyMZzCmLot/bojn9h8Av8XTnIJkHgtqqnw8FHgiR?= =?us-ascii?q?ejtX4rAdhiqV8+xwmwvdGo+toNGLICowPkcFhcwnT/wdOixxZVA/fvQHOCkUbS?= =?us-ascii?q?dYnkZqTJME0/NtzoywobVvaY42bBVMyvV0T/Di5W31G2NglaYAUpIg063ky6Di?= =?us-ascii?q?dyp0N8uUvPSUtgQ1LPWvyF94JvyvshdJVOgKmVfNrbSq+ouUNiEEm3lExcFUrt?= =?us-ascii?q?Jk57wdAsEX7zTIROTzHFRXsBOgDAb/mprjPl9b6FaNC+7iB3Q9zx14M9QvJqrW?= =?us-ascii?q?EEnOLbQsOoAURhECDw4NqpDkFPCCSHl6ZLNlhKaKhMAxN0rVinaJ7Yw9u9pAG1?= =?us-ascii?q?m++YfLTcXZBGfwemxxdqTSuJsrsUlItPiMI4Wtjdn1z6xJfovR9bBBbrL4dtZ1?= =?us-ascii?q?TIrrsFIAfvaIcEebFJHYBbfZBtAElQaEpQzmKGvnHaXWzlZrk+F4K8yy2vNxQd?= =?us-ascii?q?ylr/3P7L9fMKGRMBQtkKZvX7duWD4BAwKctCS11Kt8Huqi6nEnT7TX5gbH7m1s?= =?us-ascii?q?PVthTW7wm0VFQ1TW0C3rOe0jmagVN9FbU8Z4Cwjqe417kPDZt38WQCo5X2JpBg?= =?us-ascii?q?RX/JOHOAgrgKA0KzZ50CeHGdsZjpAbsE28d84XhQ02VKT2dDkHzpitPuSU331y?= =?us-ascii?q?1s+hVteIgBMdSlbO3BCFlBDvrHeTEgIpkqnZr5e/GSd17UZwQ3N/g0=3D?= IronPort-HdrOrdr: =?us-ascii?q?A9a23=3AmS58S6/PRHT7JJgFU+puk+C9I+orL9Y04lQ7?= =?us-ascii?q?vn2ZKCY0TiX2ra2TdZggvyMc6wxxZJhDo7+90cC7KBu2yXcc2/hzAV7IZmXbUQ?= =?us-ascii?q?WTQr1f0Q=3D=3D?= X-IronPort-AV: E=Sophos;i="5.88,304,1635177600"; d="scan'208";a="120661741" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 21 Jan 2022 16:34:20 +0800 Received: from G08CNEXMBPEKD05.g08.fujitsu.local (unknown [10.167.33.204]) by cn.fujitsu.com (Postfix) with ESMTP id 10D3A4D15A58; Fri, 21 Jan 2022 16:34:19 +0800 (CST) Received: from G08CNEXCHPEKD09.g08.fujitsu.local (10.167.33.85) by G08CNEXMBPEKD05.g08.fujitsu.local (10.167.33.204) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Fri, 21 Jan 2022 16:34:19 +0800 Received: from [192.168.22.28] (10.167.225.141) by G08CNEXCHPEKD09.g08.fujitsu.local (10.167.33.209) with Microsoft SMTP Server id 15.0.1497.23 via Frontend Transport; Fri, 21 Jan 2022 16:34:16 +0800 Message-ID: Date: Fri, 21 Jan 2022 16:34:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v9 10/10] fsdax: set a CoW flag when associate reflink mappings To: Christoph Hellwig CC: , , , , , , , , References: <20211226143439.3985960-1-ruansy.fnst@fujitsu.com> <20211226143439.3985960-11-ruansy.fnst@fujitsu.com> <70a24c20-d7ee-064c-e863-9f012422a2f5@fujitsu.com> From: Shiyang Ruan In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed X-yoursite-MailScanner-ID: 10D3A4D15A58.A4165 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: ruansy.fnst@fujitsu.com X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 38E0F1C0005 X-Stat-Signature: 3iki6kf6c6j3963hmno8g5qaykz3xgsn Authentication-Results: imf20.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=fujitsu.com (policy=none); spf=none (imf20.hostedemail.com: domain of ruansy.fnst@fujitsu.com has no SPF policy when checking 183.91.158.132) smtp.mailfrom=ruansy.fnst@fujitsu.com X-HE-Tag: 1642754062-645746 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000348, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: =E5=9C=A8 2022/1/21 15:16, Christoph Hellwig =E5=86=99=E9=81=93: > On Fri, Jan 21, 2022 at 10:33:58AM +0800, Shiyang Ruan wrote: >>> >>> But different question, how does this not conflict with: >>> >>> #define PAGE_MAPPING_ANON 0x1 >>> >>> in page-flags.h? >> >> Now we are treating dax pages, so I think its flags should be differen= t from >> normal page. In another word, PAGE_MAPPING_ANON is a flag of rmap mec= hanism >> for normal page, it doesn't work for dax page. And now, we have dax r= map >> for dax page. So, I think this two kinds of flags are supposed to be = used >> in different mechanisms and won't conflect. >=20 > It just needs someone to use folio_test_anon in a place where a DAX > folio can be passed. This probably should not happen, but we need to > clearly document that. >=20 >>> Either way I think this flag should move to page-flags.h and be >>> integrated with the PAGE_MAPPING_FLAGS infrastucture. >> >> And that's why I keep them in this dax.c file. >=20 > But that does not integrate it with the infrastructure. For people > to debug things it needs to be next to PAGE_MAPPING_ANON and have > documentation explaining why they are exclusive. Ok, understood. -- Thanks, Ruan.