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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 18D96C64E8A for ; Wed, 2 Dec 2020 11:41:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A378D20709 for ; Wed, 2 Dec 2020 11:41:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729735AbgLBLlj (ORCPT ); Wed, 2 Dec 2020 06:41:39 -0500 Received: from mx2.suse.de ([195.135.220.15]:60034 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726254AbgLBLlj (ORCPT ); Wed, 2 Dec 2020 06:41:39 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 75D70AB7F; Wed, 2 Dec 2020 11:40:57 +0000 (UTC) Date: Wed, 2 Dec 2020 11:40:54 +0000 From: Mel Gorman To: Huang Ying Cc: Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Ingo Molnar , Rik van Riel , Johannes Weiner , "Matthew Wilcox (Oracle)" , Dave Hansen , Andi Kleen , Michal Hocko , David Rientjes , linux-api@vger.kernel.org Subject: Re: [PATCH -V6 RESEND 1/3] numa balancing: Migrate on fault among multiple bound nodes Message-ID: <20201202114054.GV3306@suse.de> References: <20201202084234.15797-1-ying.huang@intel.com> <20201202084234.15797-2-ying.huang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20201202084234.15797-2-ying.huang@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 02, 2020 at 04:42:32PM +0800, Huang Ying wrote: > Now, NUMA balancing can only optimize the page placement among the > NUMA nodes if the default memory policy is used. Because the memory > policy specified explicitly should take precedence. But this seems > too strict in some situations. For example, on a system with 4 NUMA > nodes, if the memory of an application is bound to the node 0 and 1, > NUMA balancing can potentially migrate the pages between the node 0 > and 1 to reduce cross-node accessing without breaking the explicit > memory binding policy. > Ok, I think this part is ok and while the test case is somewhat superficial, it at least demonstrated that the NUMA balancing overhead did not offset any potential benefit Acked-by: Mel Gorman -- Mel Gorman SUSE Labs