From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965513AbeEIQeO (ORCPT ); Wed, 9 May 2018 12:34:14 -0400 Received: from outbound-smtp02.blacknight.com ([81.17.249.8]:40197 "EHLO outbound-smtp02.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935232AbeEIQeM (ORCPT ); Wed, 9 May 2018 12:34:12 -0400 Date: Wed, 9 May 2018 17:34:10 +0100 From: Mel Gorman To: Srikar Dronamraju Cc: torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, hpa@zytor.com, efault@gmx.de, linux-kernel@vger.kernel.org, matt@codeblueprint.co.uk, peterz@infradead.org, ggherdovich@suse.cz, linux-tip-commits@vger.kernel.org, mpe@ellerman.id.au Subject: Re: [tip:sched/core] sched/numa: Delay retrying placement for automatic NUMA balance after wake_affine() Message-ID: <20180509163410.trju4eyrtslb3sk5@techsingularity.net> References: <20180213133730.24064-7-mgorman@techsingularity.net> <20180507110607.GA3828@linux.vnet.ibm.com> <20180509084148.qzpsetz74pkg7g33@techsingularity.net> <20180509105814.GA41120@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20180509105814.GA41120@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 Wed, May 09, 2018 at 03:58:14AM -0700, Srikar Dronamraju wrote: > In the other scenario, where wake_affine set p->numa_migrate_preferred to a > bigger value, the task calls numa_migrate_preferred(), > numa_migrate_preferred could be before p->numa_migrate_preferred. In > such a case, we should have stopped the task from migration. > However we overwrite p->numa_migrate_preferred and do the > task_numa_migrate(). Somehow this doesn't seem to achieve what the > commit intended. > > Or did I misunderstand? > Nope, the logic is broken. While it can be "fixed", the end result adds complexity for very little gain. I believe the right path for the moment is a revert and retry at a future date. Thanks. -- Mel Gorman SUSE Labs