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 B5B0FCA9EBC for ; Thu, 24 Oct 2019 13:39:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 672E521BE5 for ; Thu, 24 Oct 2019 13:39:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 672E521BE5 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 CD3436B0005; Thu, 24 Oct 2019 09:39:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C83AD6B0006; Thu, 24 Oct 2019 09:39:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B73586B0007; Thu, 24 Oct 2019 09:39:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0205.hostedemail.com [216.40.44.205]) by kanga.kvack.org (Postfix) with ESMTP id 90DB66B0005 for ; Thu, 24 Oct 2019 09:39:04 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 0E0A068AB for ; Thu, 24 Oct 2019 13:39:04 +0000 (UTC) X-FDA: 76078784208.02.fish45_31ff6a132c40e X-HE-Tag: fish45_31ff6a132c40e X-Filterd-Recvd-Size: 2507 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf41.hostedemail.com (Postfix) with ESMTP for ; Thu, 24 Oct 2019 13:39:03 +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 D4BAABD14; Thu, 24 Oct 2019 13:39:01 +0000 (UTC) Date: Thu, 24 Oct 2019 15:38:59 +0200 From: Michal Hocko To: Qian Cai Cc: Andrew Morton , Waiman Long , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Roman Gushchin , Vlastimil Babka , Konstantin Khlebnikov , Jann Horn , Song Liu , Greg Kroah-Hartman , Rafael Aquini Subject: Re: [PATCH] mm/vmstat: Reduce zone lock hold time when reading /proc/pagetypeinfo Message-ID: <20191024133859.GX17610@dhcp22.suse.cz> References: <20191024074205.GQ17610@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Content-Transfer-Encoding: quoted-printable 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 Thu 24-10-19 07:11:52, Qian Cai wrote: >=20 >=20 > > On Oct 24, 2019, at 3:42 AM, Michal Hocko wrote: > >=20 > > It's been useful for debugging memory fragmentation problems and we d= o > > not have anything that would provide a similar information. Consideri= ng >=20 > Actually, zoneinfo and buddyinfo are somewhat similar to it. Why > the extra information in pagetypeinfo is still useful in debugging > today=E2=80=99s real-world scenarios? Because the migrate type is the information that helps to understand fragmentation related issues. I am pretty sure Vlastimil would tell you much more. > > that making it root only is trivial and reducing the lock hold times > > likewise I do not really see any strong reason to dump it at this > > moment. >=20 > There is no need to hurry this, and clearly this is rather a good > opportunity to discuss the consolidation of memory fragmentation > debugging to ease the maintenance in long term. Right. I think we should address the issue at hands first and then handle any possible consolidations. --=20 Michal Hocko SUSE Labs