From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751511AbcGPKfh (ORCPT ); Sat, 16 Jul 2016 06:35:37 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:34930 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751424AbcGPKff (ORCPT ); Sat, 16 Jul 2016 06:35:35 -0400 X-IBM-Helo: d06dlp03.portsmouth.uk.ibm.com X-IBM-MailFrom: sebott@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org;linux-s390@vger.kernel.org Date: Sat, 16 Jul 2016 12:35:26 +0200 (CEST) From: Sebastian Ott X-X-Sender: sebott@schleppi To: Bhaktipriya Shridhar cc: Peter Oberparleiter , Martin Schwidefsky , Heiko Carstens , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo Subject: Re: [PATCH] s390/cio/chp : Remove deprecated create_singlethread_workqueue In-Reply-To: <20160716084834.GA7728@Karyakshetra> References: <20160716084834.GA7728@Karyakshetra> User-Agent: Alpine 2.20 (LFD 67 2015-01-07) Organization: =?ISO-8859-15?Q?=22IBM_Deutschland_Research_&_Development_GmbH_=2F_Vorsitzende_des_Aufsichtsrats=3A_Martina_Koederitz_Gesch=E4ftsf=FChrung=3A_Dirk_Wittkopp_Sitz_der_Gesellschaft=3A_B=F6blingen_=2F_Registergericht?= =?ISO-8859-15?Q?=3A_Amtsgericht_Stuttgart=2C_HRB_243294=22?= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16071610-0024-0000-0000-000001F2D391 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16071610-0025-0000-0000-00001FA29243 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-07-16_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=3 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1607160130 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 16 Jul 2016, Bhaktipriya Shridhar wrote: > The workqueue "chp_wq" is involved in performing pending > configure tasks for channel paths. > > It has a single work item(&cfg_work) and hence doesn't require > ordering. Also, it is not being used on a memory reclaim path. > Hence, the singlethreaded workqueue has been replaced with the use of > system_wq. > > System workqueues have been able to handle high level of concurrency > for a long time now and hence it's not required to have a singlethreaded > workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue > created with create_singlethread_workqueue(), system_wq allows multiple > work items to overlap executions even on the same CPU; however, a > per-cpu workqueue doesn't have any CPU locality or global ordering > guarantee unless the target CPU is explicitly specified and thus the > increase of local concurrency shouldn't make any difference. > > Signed-off-by: Bhaktipriya Shridhar Applied, thanks! Sebastian