From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f41.google.com (mail-wg0-f41.google.com [74.125.82.41]) by kanga.kvack.org (Postfix) with ESMTP id 179626B0031 for ; Tue, 28 Jan 2014 04:58:32 -0500 (EST) Received: by mail-wg0-f41.google.com with SMTP id n12so5660079wgh.0 for ; Tue, 28 Jan 2014 01:58:32 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id yx1si4368540wjc.16.2014.01.28.01.58.31 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 28 Jan 2014 01:58:31 -0800 (PST) Date: Tue, 28 Jan 2014 09:58:28 +0000 From: Mel Gorman Subject: Re: [PATCH 5/9] numa,sched,mm: use active_nodes nodemask to limit numa migrations Message-ID: <20140128095828.GR4963@suse.de> References: <1390860228-21539-1-git-send-email-riel@redhat.com> <1390860228-21539-6-git-send-email-riel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1390860228-21539-6-git-send-email-riel@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: riel@redhat.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, peterz@infradead.org, mingo@redhat.com, chegu_vinod@hp.com On Mon, Jan 27, 2014 at 05:03:44PM -0500, riel@redhat.com wrote: > From: Rik van Riel > > Use the active_nodes nodemask to make smarter decisions on NUMA migrations. > > In order to maximize performance of workloads that do not fit in one NUMA > node, we want to satisfy the following criteria: > 1) keep private memory local to each thread > 2) avoid excessive NUMA migration of pages > 3) distribute shared memory across the active nodes, to > maximize memory bandwidth available to the workload > > This patch accomplishes that by implementing the following policy for > NUMA migrations: > 1) always migrate on a private fault > 2) never migrate to a node that is not in the set of active nodes > for the numa_group > 3) always migrate from a node outside of the set of active nodes, > to a node that is in that set > 4) within the set of active nodes in the numa_group, only migrate > from a node with more NUMA page faults, to a node with fewer > NUMA page faults, with a 25% margin to avoid ping-ponging > > This results in most pages of a workload ending up on the actively > used nodes, with reduced ping-ponging of pages between those nodes. > > Cc: Peter Zijlstra > Cc: Mel Gorman > Cc: Ingo Molnar > Cc: Chegu Vinod > Signed-off-by: Rik van Riel Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org