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=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D99CEC71156 for ; Thu, 3 Dec 2020 10:27:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8928121D91 for ; Thu, 3 Dec 2020 10:27:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388434AbgLCK07 (ORCPT ); Thu, 3 Dec 2020 05:26:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730279AbgLCK06 (ORCPT ); Thu, 3 Dec 2020 05:26:58 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51BCCC061A4D; Thu, 3 Dec 2020 02:26:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=XCWg7Tb5mZvG/2h9CQXFxMTAJ32rXCudkFDrtro7Gcc=; b=X4Zcth9JiusNnNnWu7clwftyDq K8OL3GQ2KYXRgp+9HQySN/sgRAPUMbF0WtNs/OOtYPr9Qty0LJ2jg5YVe4MkzOQECLOilt529ucBq yEX1qDpFCsYEAbsGf6LnwTPTAK1B1jxTvvpZjxjEyh+V0isms7IbTIpycgadu4TGpssSLt8UeLXQh AQEsJGDUy/Y4qM64Z+fVepduWehHYj6pGfPVDnwh4DmIVDfiGgRx8zjiaGNoIkMoz+fb+/hr+4X1T uAPx4fchwaaWS/WiU4zCCcs7EYFI+g3658KtLnOuKBL82Pw8yvEHn6/Gk373iNYiJQelAdEjj7cuy T+Zd7McA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kklo8-0007qk-6I; Thu, 03 Dec 2020 10:25:52 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id B1B67302753; Thu, 3 Dec 2020 11:25:50 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 9308A201BAA75; Thu, 3 Dec 2020 11:25:50 +0100 (CET) Date: Thu, 3 Dec 2020 11:25:50 +0100 From: Peter Zijlstra To: Mel Gorman Cc: Huang Ying , 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: <20201203102550.GK2414@hirez.programming.kicks-ass.net> References: <20201202084234.15797-1-ying.huang@intel.com> <20201202084234.15797-2-ying.huang@intel.com> <20201202114054.GV3306@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201202114054.GV3306@suse.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 02, 2020 at 11:40:54AM +0000, Mel Gorman wrote: > 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 Who do we expect to merge this, me through tip/sched/core or akpm ?