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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 1DA39C8303D for ; Tue, 13 Oct 2020 02:42:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDEEE2072C for ; Tue, 13 Oct 2020 02:42:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728399AbgJMBrA convert rfc822-to-8bit (ORCPT ); Mon, 12 Oct 2020 21:47:00 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:3633 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728368AbgJMBrA (ORCPT ); Mon, 12 Oct 2020 21:47:00 -0400 Received: from dggeme701-chm.china.huawei.com (unknown [172.30.72.54]) by Forcepoint Email with ESMTP id 52428B01F422E592A767; Tue, 13 Oct 2020 09:46:58 +0800 (CST) Received: from dggeme753-chm.china.huawei.com (10.3.19.99) by dggeme701-chm.china.huawei.com (10.1.199.97) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1913.5; Tue, 13 Oct 2020 09:46:57 +0800 Received: from dggeme753-chm.china.huawei.com ([10.7.64.70]) by dggeme753-chm.china.huawei.com ([10.7.64.70]) with mapi id 15.01.1913.007; Tue, 13 Oct 2020 09:46:57 +0800 From: linmiaohe To: Matthew Wilcox CC: "akpm@linux-foundation.org" , Vitaly Wool , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [Question Resend] About z3fold page migration Thread-Topic: [Question Resend] About z3fold page migration Thread-Index: AdahATPxqN5axJg6RU2xJ1rzRUeAVQ== Date: Tue, 13 Oct 2020 01:46:57 +0000 Message-ID: <5558810ec33b4b8e92145f66a4922be8@huawei.com> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.174.179.54] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Matthew Wilcox wrote: > On Mon, Oct 12, 2020 at 02:00:17PM +0000, linmiaohe wrote: >> Hi all: >> >> Many thanks for brilliant z3fold code. I am reading it and have some questions about it. It's very nice of you if you can explain it for me. >> 1.page->private is used in z3fold but PagePrivate flag is never set, should we SetPagePrivate for it? > >No. SetPagePrivate and page->private are related in interesting and complicated ways. I'm working on some documentation for it at the moment, but the short answer is: no. I can't wait to read your document. PagePrivate confuses me now. > >> 2.Since PagePrivate flag is never set, why we ClearPagePrivate in free_z3fold_page and z3fold_page_migrate? > >That's probably a bug. > > >> 3.Should we add page to the unbuddied list in z3fold_page_putback() >> when zhdr->refcount does not reach 0 since we remove it from unbuddied list in z3fold_page_isolate? Or When we will add page to the unbuddied list after z3fold_page_putback? > >This one I do not know the answer to. > Many thanks for your reply. Enjoy your day! ;)