From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756588Ab3JGSk3 (ORCPT ); Mon, 7 Oct 2013 14:40:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59240 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751466Ab3JGSk0 (ORCPT ); Mon, 7 Oct 2013 14:40:26 -0400 Message-ID: <5252FFFD.4070002@redhat.com> Date: Mon, 07 Oct 2013 14:39:57 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Mel Gorman CC: Peter Zijlstra , Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 22/63] sched: Favour moving tasks towards the preferred node References: <1381141781-10992-1-git-send-email-mgorman@suse.de> <1381141781-10992-23-git-send-email-mgorman@suse.de> In-Reply-To: <1381141781-10992-23-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/07/2013 06:29 AM, Mel Gorman wrote: > This patch favours moving tasks towards NUMA node that recorded a higher > number of NUMA faults during active load balancing. Ideally this is > self-reinforcing as the longer the task runs on that node, the more faults > it should incur causing task_numa_placement to keep the task running on that > node. In reality a big weakness is that the nodes CPUs can be overloaded > and it would be more efficient to queue tasks on an idle node and migrate > to the new node. This would require additional smarts in the balancer so > for now the balancer will simply prefer to place the task on the preferred > node for a PTE scans which is controlled by the numa_balancing_settle_count > sysctl. Once the settle_count number of scans has complete the schedule > is free to place the task on an alternative node if the load is imbalanced. > > [srikar@linux.vnet.ibm.com: Fixed statistics] > [peterz@infradead.org: Tunable and use higher faults instead of preferred] > Signed-off-by: Peter Zijlstra > Signed-off-by: Mel Gorman Acked-by: Rik van Riel -- All rights reversed