From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423499AbcFMNUf (ORCPT ); Mon, 13 Jun 2016 09:20:35 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48195 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1423115AbcFMNUe (ORCPT ); Mon, 13 Jun 2016 09:20:34 -0400 X-IBM-Helo: d06dlp03.portsmouth.uk.ibm.com X-IBM-MailFrom: schwidefsky@de.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org Date: Mon, 13 Jun 2016 15:19:42 +0200 From: Martin Schwidefsky To: Peter Zijlstra Cc: Heiko Carstens , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] s390/topology: add drawer scheduling domain level In-Reply-To: <20160613130647.GZ30909@twins.programming.kicks-ass.net> References: <1465376956-100711-1-git-send-email-heiko.carstens@de.ibm.com> <1465376956-100711-3-git-send-email-heiko.carstens@de.ibm.com> <20160613110621.GV30909@twins.programming.kicks-ass.net> <20160613112230.GA3808@osiris> <20160613130647.GZ30909@twins.programming.kicks-ass.net> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16061313-0020-0000-0000-0000020B5B4B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16061313-0021-0000-0000-00003C72EFE9 Message-Id: <20160613151942.02028e15@mschwide> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-06-13_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1606130151 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Jun 2016 15:06:47 +0200 Peter Zijlstra wrote: > On Mon, Jun 13, 2016 at 01:22:30PM +0200, Heiko Carstens wrote: > > Yes, and actually we are all virt/LPAR always, so this is unfortunately not > > very easy to do. And yes, I do agree that for the 1:1 case it most likely > > would make sense, however we don't have any run-time guarantee to stay 1:1. > > One option would be to make it a boot option; such that the > administrator has to set it. At that point, if the admin creates > multiple LPARs its on him. Unfortunately not good enough. The LPAR code tries to optimize the layout at the time a partition is activated. The landscape of already running partitions can change at this point. To get around this you would have to activate *all* partitions first and then start the operating systems in a second step. And then there is concurrent repair which will move things around if a piece of memory goes bad. This happens rarely though. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.