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,URIBL_BLOCKED,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 4D9E7C433F4 for ; Fri, 31 Aug 2018 11:54:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE60120839 for ; Fri, 31 Aug 2018 11:54:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE60120839 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 S1727675AbeHaQBH (ORCPT ); Fri, 31 Aug 2018 12:01:07 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39624 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727486AbeHaQBG (ORCPT ); Fri, 31 Aug 2018 12:01:06 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w7VBnLYF106339 for ; Fri, 31 Aug 2018 07:53:58 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2m73s73qmj-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 31 Aug 2018 07:53:57 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 31 Aug 2018 12:53:56 +0100 Received: from b06cxnps4074.portsmouth.uk.ibm.com (9.149.109.196) by e06smtp07.uk.ibm.com (192.168.101.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 31 Aug 2018 12:53:53 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w7VBrqZU35193028 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 31 Aug 2018 11:53:53 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2A72D52052; Fri, 31 Aug 2018 14:53:48 +0100 (BST) Received: from linux.vnet.ibm.com (unknown [9.40.192.68]) by d06av21.portsmouth.uk.ibm.com (Postfix) with SMTP id 6AD1E5204F; Fri, 31 Aug 2018 14:53:46 +0100 (BST) Date: Fri, 31 Aug 2018 04:53:50 -0700 From: Srikar Dronamraju To: Peter Zijlstra Cc: Ingo Molnar , LKML , Mel Gorman , Rik van Riel , Thomas Gleixner , Michael Ellerman , Heiko Carstens , Suravee Suthikulpanit , linuxppc-dev , Benjamin Herrenschmidt Subject: Re: [PATCH 2/2] sched/topology: Expose numa_mask set/clear functions to arch Reply-To: Srikar Dronamraju References: <20180808081942.GA37418@linux.vnet.ibm.com> <1533920419-17410-1-git-send-email-srikar@linux.vnet.ibm.com> <1533920419-17410-2-git-send-email-srikar@linux.vnet.ibm.com> <20180829080219.GN24124@hirez.programming.kicks-ass.net> <20180831102724.GB8437@linux.vnet.ibm.com> <20180831111253.GJ24124@hirez.programming.kicks-ass.net> <20180831112639.GA24142@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20180831112639.GA24142@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.24 (2015-08-30) X-TM-AS-GCONF: 00 x-cbid: 18083111-0028-0000-0000-000002F24A83 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18083111-0029-0000-0000-000023ABB0E1 Message-Id: <20180831115350.GC8437@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-08-31_05:,, 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=8.0.1-1807170000 definitions=main-1808310124 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Peter Zijlstra [2018-08-31 13:26:39]: > On Fri, Aug 31, 2018 at 01:12:53PM +0200, Peter Zijlstra wrote: > > NAK, not until you've fixed every cpu_to_node() user in the kernel to > > deal with that mask changing. > > Also, what happens if userspace reads that information; uses libnuma and > then you go and shift the world underneath their feet? > > > This is absolutely insane. > The topology events are suppose to be very rare. >From whatever small experiments I have done till now, unless tasks are bound to both cpu and memory, they seem to be coping well with topology updates. I know things weren't optimal after a topology change but they worked. Now after 051f3ca02e46 "Introduce NUMA identity node sched domain", systems stall. I am only exploring at ways to keep them working as much as they were before that commit. -- Thanks and Regards Srikar Dronamraju