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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 4EA66C3A5A1 for ; Thu, 29 Aug 2019 03:25:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2814922CED for ; Thu, 29 Aug 2019 03:25:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726620AbfH2DZL convert rfc822-to-8bit (ORCPT ); Wed, 28 Aug 2019 23:25:11 -0400 Received: from tyo162.gate.nec.co.jp ([114.179.232.162]:39604 "EHLO tyo162.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725844AbfH2DZK (ORCPT ); Wed, 28 Aug 2019 23:25:10 -0400 Received: from mailgate02.nec.co.jp ([114.179.233.122]) by tyo162.gate.nec.co.jp (8.15.1/8.15.1) with ESMTPS id x7T3Or8A010001 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 29 Aug 2019 12:24:53 +0900 Received: from mailsv02.nec.co.jp (mailgate-v.nec.co.jp [10.204.236.94]) by mailgate02.nec.co.jp (8.15.1/8.15.1) with ESMTP id x7T3Or60018255; Thu, 29 Aug 2019 12:24:53 +0900 Received: from mail03.kamome.nec.co.jp (mail03.kamome.nec.co.jp [10.25.43.7]) by mailsv02.nec.co.jp (8.15.1/8.15.1) with ESMTP id x7T3Or8q018852; Thu, 29 Aug 2019 12:24:53 +0900 Received: from bpxc99gp.gisp.nec.co.jp ([10.38.151.152] [10.38.151.152]) by mail03.kamome.nec.co.jp with ESMTP id BT-MMP-545660; Thu, 29 Aug 2019 10:47:15 +0900 Received: from BPXM20GP.gisp.nec.co.jp ([10.38.151.212]) by BPXC24GP.gisp.nec.co.jp ([10.38.151.152]) with mapi id 14.03.0439.000; Thu, 29 Aug 2019 10:47:14 +0900 From: Toshiki Fukasawa To: Waiman Long , Michal Hocko CC: Dan Williams , Alexey Dobriyan , Andrew Morton , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , Stephen Rothwell , "Michael S. Tsirkin" , Junichi Nomura , Toshiki Fukasawa Subject: Re: [PATCH v2] fs/proc/page: Skip uninitialized page when iterating page structures Thread-Topic: [PATCH v2] fs/proc/page: Skip uninitialized page when iterating page structures Thread-Index: AQHVXab+AB6W4hF4zE+DO3WxOpzL56cQAkYAgAACh4CAAMCOgA== Date: Thu, 29 Aug 2019 01:47:13 +0000 Message-ID: <9a1395bc-d568-c4d7-2dde-7dde7b48ac0b@vx.jp.nec.com> References: <20190826124336.8742-1-longman@redhat.com> <20190827142238.GB10223@dhcp22.suse.cz> <20190828080006.GG7386@dhcp22.suse.cz> <8363a4ba-e26f-f88c-21fc-5dd1fe64f646@redhat.com> <20190828140938.GL28313@dhcp22.suse.cz> <4367f507-97ba-a74e-6bf5-811cdd6ecdf9@redhat.com> In-Reply-To: <4367f507-97ba-a74e-6bf5-811cdd6ecdf9@redhat.com> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.34.125.135] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <43FF7CD7AC5C9E4DA042E82DA36846D9@gisp.nec.co.jp> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/08/28 23:18, Waiman Long wrote: > On 8/28/19 10:09 AM, Michal Hocko wrote: >> On Wed 28-08-19 09:46:21, Waiman Long wrote: >>> On 8/28/19 4:00 AM, Michal Hocko wrote: >>>> On Tue 27-08-19 16:22:38, Michal Hocko wrote: >>>>> Dan, isn't this something we have discussed recently? >>>> This was http://lkml.kernel.org/r/20190725023100.31141-3-t-fukasawa@vx.jp.nec.com >>>> and talked about /proc/kpageflags but this is essentially the same thing >>>> AFAIU. I hope we get a consistent solution for both issues. >>>> >>> Yes, it is the same problem. The uninitialized page structure problem >>> affects all the 3 /proc/kpage{cgroup,count,flags) files. >>> >>> Toshiki's patch seems to fix it just for /proc/kpageflags, though. >> Yup. I was arguing that whacking a mole kinda fix is far from good. Dan >> had some arguments on why initializing those struct pages is a problem. >> The discussion had a half open end though. I hoped that Dan would try >> out the initialization side but I migh have misunderstood. > > If the page structures of the reserved PFNs are always initialized, that > will fix the problem too. I am not familiar with the zone device code. > So I didn't attempt to do that. > > Cheers, > Longman > > I also think that the struct pages should be initialized. I'm preparing to post the patch. Toshiki Fukasawa