From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751803AbeFEI6n (ORCPT ); Tue, 5 Jun 2018 04:58:43 -0400 Received: from outbound-smtp27.blacknight.com ([81.17.249.195]:36170 "EHLO outbound-smtp27.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591AbeFEI6m (ORCPT ); Tue, 5 Jun 2018 04:58:42 -0400 Date: Tue, 5 Jun 2018 09:58:40 +0100 From: Mel Gorman To: Srikar Dronamraju Cc: Ingo Molnar , Peter Zijlstra , LKML , Rik van Riel , Thomas Gleixner Subject: Re: [PATCH 09/19] sched/numa: Modify migrate_swap to accept additional params Message-ID: <20180605085840.5film7evducjmirf@techsingularity.net> References: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com> <1528106428-19992-10-git-send-email-srikar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1528106428-19992-10-git-send-email-srikar@linux.vnet.ibm.com> User-Agent: NeoMutt/20170912 (1.9.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 04, 2018 at 03:30:18PM +0530, Srikar Dronamraju wrote: > There are checks in migrate_swap_stop that check if the task/cpu > combination is as per migrate_swap_arg before migrating. > > However atleast one of the two tasks to be swapped by migrate_swap could > have migrated to a completely different cpu before updating the > migrate_swap_arg. The new cpu where the task is currently running could > be a different node too. If the task has migrated, numa balancer might > end up placing a task in a wrong node. Instead of achieving node > consolidation, it may end up spreading the load across nodes. > > To avoid that pass the cpus as additional parameters. > > While here, place migrate_swap under CONFIG_NUMA_BALANCING. > > Signed-off-by: Srikar Dronamraju Acked-by: Mel Gorman -- Mel Gorman SUSE Labs