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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 4E95FC3A5A1 for ; Wed, 28 Aug 2019 14:09:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 215AE23407 for ; Wed, 28 Aug 2019 14:09:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567001382; bh=NbxD37/YZywxtJEqp4Mp+jtxWAYcea3eBo2cQaaKeG8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qANatjNz3HwNsOkaFvCZyAeVBworM9vMHPZxXTuYmyMdlmM+CJqAkvx+c1UQEVvNM x2OYjjw7hzQ8OvZzj+/HSQf8y5jDArWBuCO1cJO/VmDfdrp4DbC3dfUqA6BVemLqTU CiFZc92SJcTDeiHuxJXTt/gPMe4hMylKUBFAKBug= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726719AbfH1OJl (ORCPT ); Wed, 28 Aug 2019 10:09:41 -0400 Received: from mx2.suse.de ([195.135.220.15]:42882 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726515AbfH1OJk (ORCPT ); Wed, 28 Aug 2019 10:09:40 -0400 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) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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