From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752708AbeFDMSL (ORCPT ); Mon, 4 Jun 2018 08:18:11 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:58858 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751933AbeFDMSJ (ORCPT ); Mon, 4 Jun 2018 08:18:09 -0400 Date: Mon, 4 Jun 2018 14:18:00 +0200 From: Peter Zijlstra To: Srikar Dronamraju Cc: Ingo Molnar , LKML , Mel Gorman , Rik van Riel , Thomas Gleixner Subject: Re: [PATCH 04/19] sched/numa: Set preferred_node based on best_cpu Message-ID: <20180604121800.GR12217@hirez.programming.kicks-ass.net> References: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com> <1528106428-19992-5-git-send-email-srikar@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1528106428-19992-5-git-send-email-srikar@linux.vnet.ibm.com> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 04, 2018 at 03:30:13PM +0530, Srikar Dronamraju wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index ea32a66..94091e6 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1725,8 +1725,9 @@ static int task_numa_migrate(struct task_struct *p) > * Tasks that are "trapped" in such domains cannot be migrated > * elsewhere, so there is no point in (re)trying. > */ > - if (unlikely(!sd)) { > - p->numa_preferred_nid = task_node(p); > + if (unlikely(!sd) && p->numa_preferred_nid != task_node(p)) { > + /* Set the new preferred node */ > + sched_setnuma(p, task_node(p)); > return -EINVAL; > } > That looks dodgy.. this would allow things to continue with !sd.