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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 D7153CA9EBD for ; Fri, 25 Oct 2019 21:25:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A90E121872 for ; Fri, 25 Oct 2019 21:25:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572038733; bh=kEfjHO6oNibA4rpD7BZt5/bc6vP5kbCOVkqfe8i1laE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=xqpTCUB0RQc97dr/Xp4y+j0Le5wg8cXcIhI4kyvEudET6nPF/heOSS22wMoN9NNWK QFNMBc8J0Upvv3Ug+fNqfPM1P56yITABgCphttrL9iISGSWQByWZM+bemO+UgbFHaq fW09YcLvDCBcOIfQOmcVR6zwKPldFUyToJSZygEQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726262AbfJYVZc (ORCPT ); Fri, 25 Oct 2019 17:25:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:58700 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725283AbfJYVZc (ORCPT ); Fri, 25 Oct 2019 17:25:32 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 537C92084C; Fri, 25 Oct 2019 21:25:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572038729; bh=kEfjHO6oNibA4rpD7BZt5/bc6vP5kbCOVkqfe8i1laE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=vBxLZda3SmNmIzubNaJAHWdryG5otSiXjxJo39W1tZUQUwHG1J/Udt9gww0bvwi7G G20Cp/tzU39paZxYD6ka53naYFEFeBbM3G+JOrzkw5m9FeIWxtWzMqHgTncMl0aEhK OsRipbz7jkiF7DWKiv5fEfAk2WRjMnKGDvTKnpeU= Date: Fri, 25 Oct 2019 14:25:28 -0700 From: Andrew Morton To: Qian Cai Cc: Michal Hocko , Mel Gorman , Waiman Long , Johannes Weiner , Roman Gushchin , Vlastimil Babka , Konstantin Khlebnikov , Jann Horn , Song Liu , Greg Kroah-Hartman , Rafael Aquini , linux-mm@kvack.org, LKML , Michal Hocko Subject: Re: [PATCH 2/2] mm, vmstat: reduce zone->lock holding time by /proc/pagetypeinfo Message-Id: <20191025142528.366148a0ffadf80946d62bbb@linux-foundation.org> In-Reply-To: <192965B3-B446-499C-AEE8-DFF087D46B87@lca.pw> References: <192965B3-B446-499C-AEE8-DFF087D46B87@lca.pw> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 25 Oct 2019 07:18:37 -0400 Qian Cai wrote: >  > > > On Oct 25, 2019, at 3:26 AM, Michal Hocko wrote: > > > > Considering the pagetypeinfo is a debugging tool we do not really need > > exact numbers here. The primary reason to look at the outuput is to see > > how pageblocks are spread among different migratetypes and low number of > > pages is much more interesting therefore putting a bound on the number > > of pages on the free_list sounds like a reasonable tradeoff. > > > > The new output will simply tell > > [...] > > Node 6, zone Normal, type Movable >100000 >100000 >100000 >100000 41019 31560 23996 10054 3229 983 648 > > It was mentioned that developers could use this file is to see the movement of those numbers for debugging, so this supposed to introduce regressions as there is no movement anymore for those 100k+ items? There are risks, but we have to do something! I'd be inclined to remove the ">" though - that'll unnecessarily break code which parses this data. otoh, maybe that's a feature: breaking those parsers will alert people to go in and find out what changed.