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 8AF5CC433DF for ; Tue, 13 Oct 2020 01:47:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B905B2087E for ; Tue, 13 Oct 2020 01:47:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B905B2087E Authentication-Results: mail.kernel.org; dmarc=none (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 3978D940007; Mon, 12 Oct 2020 21:47:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 31DCD900002; Mon, 12 Oct 2020 21:47:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1E5E0940007; Mon, 12 Oct 2020 21:47:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id E5D22900002 for ; Mon, 12 Oct 2020 21:47:02 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 883731EF1 for ; Tue, 13 Oct 2020 01:47:02 +0000 (UTC) X-FDA: 77365213884.07.eye22_2e00bab271ff Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id 70E5D1803F9A4 for ; Tue, 13 Oct 2020 01:47:02 +0000 (UTC) X-HE-Tag: eye22_2e00bab271ff X-Filterd-Recvd-Size: 2766 Received: from huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Oct 2020 01:47:01 +0000 (UTC) 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: quoted-printable MIME-Version: 1.0 X-CFilter-Loop: Reflected 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: Matthew Wilcox wrote: > On Mon, Oct 12, 2020 at 02:00:17PM +0000, linmiaohe wrote: >> Hi all: >>=20 >> Many thanks for brilliant z3fold code. I am reading it and have some qu= estions 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, sh= ould we SetPagePrivate for it? > >No. SetPagePrivate and page->private are related in interesting and compl= icated ways. I'm working on some documentation for it at the moment, but t= he 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()=20 >> when zhdr->refcount does not reach 0 since we remove it from unbuddied l= ist 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! ;)