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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 D5660C2B9F7 for ; Fri, 28 May 2021 14:39:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4FFF613C9 for ; Fri, 28 May 2021 14:39:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236421AbhE1OlS (ORCPT ); Fri, 28 May 2021 10:41:18 -0400 Received: from mga03.intel.com ([134.134.136.65]:19075 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236332AbhE1OlI (ORCPT ); Fri, 28 May 2021 10:41:08 -0400 IronPort-SDR: +tkowm8VDek7IXjxh2N1ESoAaDP/g/gyJtHRZH1pxR0OeccAK0ybnJs2OhdIVmd6h+5grGKzu7 0lYAkJvqnDJQ== X-IronPort-AV: E=McAfee;i="6200,9189,9998"; a="203001921" X-IronPort-AV: E=Sophos;i="5.83,229,1616482800"; d="scan'208";a="203001921" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2021 07:39:32 -0700 IronPort-SDR: 2a6rd7eHfNnn9G08o28SW4+k/wLRHR+FGambmhbJqOqXg0uAiCDbJ2QlFnXrRDPpsID/+yb+X9 g6MrJ2FjD/LA== X-IronPort-AV: E=Sophos;i="5.83,229,1616482800"; d="scan'208";a="481068021" Received: from yihleong-mobl.amr.corp.intel.com (HELO [10.255.228.69]) ([10.255.228.69]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2021 07:39:31 -0700 Subject: Re: [PATCH 0/6 v2] Calculate pcp->high based on zone sizes and active CPUs To: Mel Gorman Cc: Andrew Morton , Hillf Danton , Dave Hansen , Vlastimil Babka , Michal Hocko , LKML , Linux-MM , "Tang, Feng" References: <20210525080119.5455-1-mgorman@techsingularity.net> <7177f59b-dc05-daff-7dc6-5815b539a790@intel.com> <20210528085545.GJ30378@techsingularity.net> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210528085545.GJ30378@techsingularity.net> Content-Type: text/plain; charset=US-ASCII Content-Language: en-US Content-Transfer-Encoding: 7BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/28/21 1:55 AM, Mel Gorman wrote: > - * onlined. > - */ > - nr_local_cpus = max(1U, cpumask_weight(cpumask_of_node(zone_to_nid(zone)))) + cpu_online; > - high = total_pages / nr_local_cpus; > + * onlined. For memory nodes that have no CPUs, split pcp->high across > + * all online CPUs to mitigate the risk that reclaim is triggered > + * prematurely due to pages stored on pcp lists. > + */ > + nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online; > + if (!nr_split_cpus) > + nr_split_cpus = num_online_cpus(); > + high = total_pages / nr_split_cpus; Updated version looks fine to me, thanks! BTW, to do some of this testing, Feng was doing a plain old kernel build. On the one system where this got run, he noted a ~2% regression in build times. Nothing major, but you might want to be on the lookout in case 0day or the other test harnesses find something similar once this series gets to them. Acked-by: Dave Hansen