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=-2.5 required=3.0 tests=MAILING_LIST_MULTI, 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 9B3D9C3A5A6 for ; Wed, 28 Aug 2019 14:09:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 540322189D for ; Wed, 28 Aug 2019 14:09:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 540322189D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DF7DE6B0008; Wed, 28 Aug 2019 10:09:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D814D6B000C; Wed, 28 Aug 2019 10:09:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C97F46B000D; Wed, 28 Aug 2019 10:09:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0228.hostedemail.com [216.40.44.228]) by kanga.kvack.org (Postfix) with ESMTP id A2C6B6B0008 for ; Wed, 28 Aug 2019 10:09:41 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 25E2582437C9 for ; Wed, 28 Aug 2019 14:09:41 +0000 (UTC) X-FDA: 75872019762.06.wrist99_376a17d0c2604 X-HE-Tag: wrist99_376a17d0c2604 X-Filterd-Recvd-Size: 2325 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Wed, 28 Aug 2019 14:09:40 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 50EFEAE92; Wed, 28 Aug 2019 14:09:39 +0000 (UTC) Date: Wed, 28 Aug 2019 16:09:38 +0200 From: Michal Hocko To: Waiman Long 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" , Toshiki Fukasawa Subject: Re: [PATCH v2] fs/proc/page: Skip uninitialized page when iterating page structures Message-ID: <20190828140938.GL28313@dhcp22.suse.cz> References: <20190826124336.8742-1-longman@redhat.com> <20190827142238.GB10223@dhcp22.suse.cz> <20190828080006.GG7386@dhcp22.suse.cz> <8363a4ba-e26f-f88c-21fc-5dd1fe64f646@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8363a4ba-e26f-f88c-21fc-5dd1fe64f646@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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 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. -- Michal Hocko SUSE Labs