From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5E51C3279B for ; Wed, 4 Jul 2018 11:19:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 53BD024496 for ; Wed, 4 Jul 2018 11:19:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 53BD024496 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753743AbeGDLTc (ORCPT ); Wed, 4 Jul 2018 07:19:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41834 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753600AbeGDLTb (ORCPT ); Wed, 4 Jul 2018 07:19:31 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w64BJTNc132683 for ; Wed, 4 Jul 2018 07:19:30 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2k0vm59nus-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 04 Jul 2018 07:19:30 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 4 Jul 2018 12:19:15 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w64BJEuJ27852846 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 4 Jul 2018 11:19:15 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0C3CCA4055; Wed, 4 Jul 2018 14:19:40 +0100 (BST) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EB3AEA4051; Wed, 4 Jul 2018 14:19:38 +0100 (BST) Received: from linux.vnet.ibm.com (unknown [9.40.192.68]) by d06av23.portsmouth.uk.ibm.com (Postfix) with SMTP; Wed, 4 Jul 2018 14:19:38 +0100 (BST) Date: Wed, 4 Jul 2018 04:19:13 -0700 From: Srikar Dronamraju To: Mel Gorman Cc: Ingo Molnar , Peter Zijlstra , LKML , Rik van Riel , Thomas Gleixner Subject: Re: [PATCH v2 18/19] sched/numa: Reset scan rate whenever task moves across nodes Reply-To: Srikar Dronamraju References: <1529514181-9842-1-git-send-email-srikar@linux.vnet.ibm.com> <1529514181-9842-19-git-send-email-srikar@linux.vnet.ibm.com> <20180621100505.a6gzpn7r6yj2gkgd@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20180621100505.a6gzpn7r6yj2gkgd@techsingularity.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 18070411-4275-0000-0000-000002951102 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18070411-4276-0000-0000-0000379C94CA Message-Id: <20180704111913.GB21902@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-07-04_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807040131 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > We talked about this before but I would at least suggest that you not > reset the scan if moving to the preferred node or if the node movement > has nothing to do with the preferred nid. e.g. > I understand your concern and okay to drop this patch for now. I will try to rework and come back later. > /* > * Ignore if the migration is not changing node, if it is migrating to > * the preferred node or moving between two nodes that are not preferred > */ > > if (p->numa_faults) { > int src_nid = cpu_to_node(task_cpu(p)); > int dst_nid = cpu_to_node(new_cpu); > > if (src_nid == dst_nid || dst_nid == p->numa_preferred_nid || > (p->numa_preferred_nid != -1 && src_nid != p->numa_preferred_nid)) With out this change/patch, we used to reduce our scan rate whenever numa balancer moved a task to a preferred node. This was made to verify that the task movement was correct. The check ( dst_nid == p->numa_preferred_nid) will negate that verification. I thought the whole point of reducing the scan period was to correct if we choose a wrong node. > return; > > p->numa_scan_period = task_scan_start(p); > > Note too that the next scan can be an arbitrary amount of time in the > future. Consider as an alternative to schedule an immediate scan instead > of adjusting the rate with > > p->mm->numa_next_scan = jiffies; > I will try to work along these lines. Though the scan happens immediately the task placement will not happen immediately so I am not sure if it would help much. > That might be less harmful in terms of overhead while still collecting > some data in the short-term. > -- Thanks and Regards Srikar