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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 285D5C433ED for ; Fri, 23 Apr 2021 10:26:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 902726141C for ; Fri, 23 Apr 2021 10:26:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 902726141C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E01B98E000C; Fri, 23 Apr 2021 06:26:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DAF1E8E0009; Fri, 23 Apr 2021 06:26:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C2C0A8E000C; Fri, 23 Apr 2021 06:26:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0099.hostedemail.com [216.40.44.99]) by kanga.kvack.org (Postfix) with ESMTP id 934798E0009 for ; Fri, 23 Apr 2021 06:26:53 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 5C4D2362D for ; Fri, 23 Apr 2021 10:26:53 +0000 (UTC) X-FDA: 78063253506.23.09922C2 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) by imf22.hostedemail.com (Postfix) with ESMTP id 7FAF1C0007F4 for ; Fri, 23 Apr 2021 10:26:46 +0000 (UTC) Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4FRVkT5xwtzPt7K; Fri, 23 Apr 2021 18:23:45 +0800 (CST) Received: from [10.136.110.154] (10.136.110.154) by smtp.huawei.com (10.3.19.205) with Microsoft SMTP Server (TLS) id 14.3.498.0; Fri, 23 Apr 2021 18:26:47 +0800 Subject: Re: [RFC] Reclaiming PG_private To: Matthew Wilcox , , CC: References: <20210422154705.GO3596236@casper.infradead.org> From: Chao Yu Message-ID: <0367408f-f9c7-a232-7339-51b27fb133ef@huawei.com> Date: Fri, 23 Apr 2021 18:26:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20210422154705.GO3596236@casper.infradead.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.136.110.154] X-CFilter-Loop: Reflected X-Stat-Signature: 39ob7dnunfbte1oudbbxu3bneqpa7rxe X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7FAF1C0007F4 Received-SPF: none (huawei.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=szxga05-in.huawei.com; client-ip=45.249.212.191 X-HE-DKIM-Result: none/none X-HE-Tag: 1619173606-733168 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 2021/4/22 23:47, Matthew Wilcox wrote: > So ... what's going on with f2fs? Does it need to distinguish between > a page which has f2fs_set_page_private(page, 0) called on it, and a page > which has had f2fs_clear_page_private() called on it? Yes, its intention here is just using Pageprivate to indicate there is some reference counts related to a dirty page, so value in page.private is meaningless. I guess we can avoid f2fs_set_page_private(page, 0) usage, instead, try to use SetPagePrivate() and assign page.private with non-zero value at the time. Thanks,