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 57191CA9EAF for ; Thu, 24 Oct 2019 13:39:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2716F20679 for ; Thu, 24 Oct 2019 13:39:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571924345; bh=vua3rl+jfj3mQkdazyKiysuDEtf/LrM/PTTNpTWXmpw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=TNtQfajBQQUS/NhlmOLrNCNG1/nmfEFh0OwTL2okkAVgkXsjZYhnb5LSy+RKwDZKg oTsdIX0Fzc9auwdwYfR9pRdionYGXzc59rkPC21bUGALRKAxSdOzTdcHTA9uQr1sW/ s8e34EHWmnDUAsQYfLmBvpRPCxCxRp4FNwK2xGFQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393633AbfJXNjE (ORCPT ); Thu, 24 Oct 2019 09:39:04 -0400 Received: from mx2.suse.de ([195.135.220.15]:46778 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1733296AbfJXNjD (ORCPT ); Thu, 24 Oct 2019 09:39:03 -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 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 Content-Transfer-Encoding: 8bit In-Reply-To: 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 Thu 24-10-19 07:11:52, Qian Cai wrote: > > > > On Oct 24, 2019, at 3:42 AM, Michal Hocko wrote: > > > > It's been useful for debugging memory fragmentation problems and we do > > not have anything that would provide a similar information. Considering > > Actually, zoneinfo and buddyinfo are somewhat similar to it. Why > the extra information in pagetypeinfo is still useful in debugging > today’s 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. > > 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. -- Michal Hocko SUSE Labs