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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 AF53DC31E57 for ; Mon, 17 Jun 2019 13:07:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A4EE2089E for ; Mon, 17 Jun 2019 13:07:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727834AbfFQNHO (ORCPT ); Mon, 17 Jun 2019 09:07:14 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:52012 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725983AbfFQNHO (ORCPT ); Mon, 17 Jun 2019 09:07:14 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5HD09mS077636; Mon, 17 Jun 2019 09:06:56 -0400 Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 2t69mpcmxg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 17 Jun 2019 09:06:56 -0400 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.0.27/8.16.0.27) with SMTP id x5HD2nlr017232; Mon, 17 Jun 2019 13:06:56 GMT Received: from b01cxnp22034.gho.pok.ibm.com (b01cxnp22034.gho.pok.ibm.com [9.57.198.24]) by ppma01wdc.us.ibm.com with ESMTP id 2t4ra6ddyn-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 17 Jun 2019 13:06:56 +0000 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5HD6sxS18284920 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 17 Jun 2019 13:06:54 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0E70BB2066; Mon, 17 Jun 2019 13:06:54 +0000 (GMT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E1D6EB205F; Mon, 17 Jun 2019 13:06:53 +0000 (GMT) Received: from paulmck-ThinkPad-W541 (unknown [9.85.132.58]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 17 Jun 2019 13:06:53 +0000 (GMT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id 5A87016C17E5; Mon, 17 Jun 2019 06:06:57 -0700 (PDT) Date: Mon, 17 Jun 2019 06:06:57 -0700 From: "Paul E. McKenney" To: Mark Rutland Cc: linux@arm.linux.org.uk, dietmar.eggemann@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH arm] Use common outgoing-CPU-notification code Message-ID: <20190617130657.GL26519@linux.ibm.com> Reply-To: paulmck@linux.ibm.com References: <20190611192410.GA27930@linux.ibm.com> <20190617115809.GA3767@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190617115809.GA3767@lakrids.cambridge.arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-17_06:,, 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=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906170119 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 17, 2019 at 12:58:19PM +0100, Mark Rutland wrote: > On Tue, Jun 11, 2019 at 12:24:10PM -0700, Paul E. McKenney wrote: > > This commit removes the open-coded CPU-offline notification with new > > common code. In particular, this change avoids calling scheduler code > > using RCU from an offline CPU that RCU is ignoring. This is a minimal > > change. A more intrusive change might invoke the cpu_check_up_prepare() > > and cpu_set_state_online() functions at CPU-online time, which would > > allow onlining throw an error if the CPU did not go offline properly. > > > > Signed-off-by: Paul E. McKenney > > Cc: linux-arm-kernel@lists.infradead.org > > Cc: Russell King > > Cc: Mark Rutland > > Tested-by: Dietmar Eggemann > > FWIW: > > Acked-by: Mark Rutland > > On the assumption that Russell is ok with this, I think this should be > dropped into the ARM patch system [1]. > > Paul, are you familiar with that, or would you prefer that someone else > submits the patch there? I can do so if you'd like. I never have used this system, so please do drop it in there! Let me know when you have done so, and I will then drop it from -rcu. Thanx, Paul > Thanks, > Mark. > > [1] https://www.armlinux.org.uk/developer/patches/info.php > > > > > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > > index ebc53804d57b..8687d619260f 100644 > > --- a/arch/arm/kernel/smp.c > > +++ b/arch/arm/kernel/smp.c > > @@ -267,15 +267,13 @@ int __cpu_disable(void) > > return 0; > > } > > > > -static DECLARE_COMPLETION(cpu_died); > > - > > /* > > * called on the thread which is asking for a CPU to be shutdown - > > * waits until shutdown has completed, or it is timed out. > > */ > > void __cpu_die(unsigned int cpu) > > { > > - if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { > > + if (!cpu_wait_death(cpu, 5)) { > > pr_err("CPU%u: cpu didn't die\n", cpu); > > return; > > } > > @@ -322,7 +320,7 @@ void arch_cpu_idle_dead(void) > > * this returns, power and/or clocks can be removed at any point > > * from this CPU and its cache by platform_cpu_kill(). > > */ > > - complete(&cpu_died); > > + (void)cpu_report_death(); > > > > /* > > * Ensure that the cache lines associated with that completion are > > >