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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2771FC4332F for ; Thu, 20 Oct 2022 07:28:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229823AbiJTH2C (ORCPT ); Thu, 20 Oct 2022 03:28:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229779AbiJTH2A (ORCPT ); Thu, 20 Oct 2022 03:28:00 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC39A15F31A; Thu, 20 Oct 2022 00:27:56 -0700 (PDT) Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 29K786ch019627; Thu, 20 Oct 2022 07:27:45 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=date : from : to : cc : subject : message-id : references : content-type : in-reply-to : mime-version; s=pp1; bh=76b4s0g5OpacSJJ4kiOMB0gSt2osK1uQ3hQIT2NW/Qo=; b=j8g5aG+RbzO63TiNeR/RVqUmuH/vqhChPQlKgX5UrlHjz6btxG3hlH4c2mYCH73/GjAl k0ILVYVQCs04GybWxEIVQZPs7Unfe34U3YbWRrcvrSaFp9+lkEiWnkIZ7G0JtOLLfiRk 4KB+8SfQocGmcYG+meF3108NlU+E8uXJRP5YNR4YNPRhSKQupdfVqSz6ccQCV7PU8uqM jlCNp58sqSeZ3ZMiclW4yFISAVLjMvRg+Fl+UTWcJ3soIUfZ+geOQ9VrddklEmdIHEfQ jQ/4D7sL8W37So67L2d3Woco19GSP8Ui/r4eNE5v/jUO8uWHpu8/ZfJADLxADYy7sM6Z yA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3kaxvfvujn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Oct 2022 07:27:45 +0000 Received: from m0098404.ppops.net (m0098404.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 29K78C39020549; Thu, 20 Oct 2022 07:27:44 GMT Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3kaxvfvuhj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Oct 2022 07:27:44 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 29K7KKpe027799; Thu, 20 Oct 2022 07:27:42 GMT Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by ppma06ams.nl.ibm.com with ESMTP id 3kajmrs5n4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 20 Oct 2022 07:27:41 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 29K7RcMm1049278 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Oct 2022 07:27:38 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9BDA752051; Thu, 20 Oct 2022 07:27:38 +0000 (GMT) Received: from osiris (unknown [9.152.212.239]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTPS id 2C9975204E; Thu, 20 Oct 2022 07:27:38 +0000 (GMT) Date: Thu, 20 Oct 2022 09:27:37 +0200 From: Heiko Carstens To: Heiko Carstens Cc: Christian Borntraeger , "Paul E. McKenney" , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, Neeraj Upadhyay , Frederic Weisbecker , Boqun Feng , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Thomas Gleixner , John Ogness , Petr Mladek , linux-s390@vger.kernel.org Subject: Re: [PATCH v3 rcu 08/11] arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option Message-ID: References: <20221019225838.GA2500612@paulmck-ThinkPad-P17-Gen-1> <20221019225846.2501109-8-paulmck@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: UDKphAujlv8J1PZYU3H9b4TpBSZgSete X-Proofpoint-GUID: -GAMInkg2xOXh_cknrok7edWDN-txW4l X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-20_02,2022-10-19_04,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 mlxlogscore=708 priorityscore=1501 lowpriorityscore=0 suspectscore=0 bulkscore=0 spamscore=0 impostorscore=0 mlxscore=0 phishscore=0 clxscore=1015 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210200041 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 20, 2022 at 09:23:49AM +0200, Heiko Carstens wrote: > On Thu, Oct 20, 2022 at 07:16:44AM +0200, Christian Borntraeger wrote: > > Am 20.10.22 um 00:58 schrieb Paul E. McKenney: > > > The s390 architecture uses either a cmpxchg loop (old systems) > > > or the laa add-to-memory instruction (new systems) to implement > > > this_cpu_add(), both of which are NMI safe. This means that the old > > > and more-efficient srcu_read_lock() may be used in NMI context, without > > > the need for srcu_read_lock_nmisafe(). Therefore, add the new Kconfig > > > option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/arm64/Kconfig, which will > > s390 ? Ah, this typo is what Christian pointed out; missed that. > > > cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current > > > srcu_read_lock() behavior. > > > > > > Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/ > > > > > > Suggested-by: Neeraj Upadhyay > > > Suggested-by: Frederic Weisbecker > > > Suggested-by: Boqun Feng > > > Signed-off-by: Paul E. McKenney > ... > > > --- > > > arch/s390/Kconfig | 1 + > > > 1 file changed, 1 insertion(+) > > Not sure what Christian was trying to say with his empty reply :) > In any case: > Acked-by: Heiko Carstens