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 7987DEDE9A8 for ; Thu, 14 Sep 2023 11:47:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234334AbjINLrc (ORCPT ); Thu, 14 Sep 2023 07:47:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236561AbjINLrc (ORCPT ); Thu, 14 Sep 2023 07:47:32 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E137BB; Thu, 14 Sep 2023 04:47:27 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rmb6D5jBWz67cSL; Thu, 14 Sep 2023 19:42:44 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Thu, 14 Sep 2023 12:47:25 +0100 Date: Thu, 14 Sep 2023 12:47:24 +0100 From: Jonathan Cameron To: James Morse CC: , , , , , , , , , Salil Mehta , Russell King , Jean-Philippe Brucker , , Subject: Re: [RFC PATCH v2 09/35] LoongArch: Switch over to GENERIC_CPU_DEVICES Message-ID: <20230914124724.000027f3@Huawei.com> In-Reply-To: <20230913163823.7880-10-james.morse@arm.com> References: <20230913163823.7880-1-james.morse@arm.com> <20230913163823.7880-10-james.morse@arm.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100006.china.huawei.com (7.191.160.224) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Wed, 13 Sep 2023 16:37:57 +0000 James Morse wrote: > Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be > overridden by the arch code, switch over to this to allow common code > to choose when the register_cpu() call is made. > > This allows topology_init() to be removed. > > This is an intermediate step to the logic being moved to drivers/acpi, > where GENERIC_CPU_DEVICES will do the work when booting with acpi=off. > > Signed-off-by: James Morse > --- > arch/loongarch/Kconfig | 1 + > arch/loongarch/kernel/topology.c | 29 ++--------------------------- > 2 files changed, 3 insertions(+), 27 deletions(-) > > diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig > index 2bddd202470e..5bed51adc68c 100644 > --- a/arch/loongarch/Kconfig > +++ b/arch/loongarch/Kconfig > @@ -72,6 +72,7 @@ config LOONGARCH > select GENERIC_CLOCKEVENTS > select GENERIC_CMOS_UPDATE > select GENERIC_CPU_AUTOPROBE > + select GENERIC_CPU_DEVICES > select GENERIC_ENTRY > select GENERIC_GETTIMEOFDAY > select GENERIC_IOREMAP if !ARCH_IOREMAP > diff --git a/arch/loongarch/kernel/topology.c b/arch/loongarch/kernel/topology.c > index caa7cd859078..8e4441c1ff39 100644 > --- a/arch/loongarch/kernel/topology.c > +++ b/arch/loongarch/kernel/topology.c > @@ -7,20 +7,13 @@ > #include > #include > > -static DEFINE_PER_CPU(struct cpu, cpu_devices); > - > #ifdef CONFIG_HOTPLUG_CPU > int arch_register_cpu(int cpu) > { > - int ret; > struct cpu *c = &per_cpu(cpu_devices, cpu); > > - c->hotpluggable = 1; This is a bit subtle. Can loongarch hotplug a CPU that is also io_master(cpu)? I have no idea if there is a subtle difference between. 1) CPUs present at boot where if they are an io_master they are not allowed to be hot removed. 2) CPUs that turn up (hotplugged) later which are an io_master and by original code can be removed. My guess is that no io_master CPU can be hotplugged in making this irrelevant and your code correct as the =1 is just a micro optimizatoin. If we can confirm that, a one line addition to the patch description would be great. Otherwise LGTM > - ret = register_cpu(c, cpu); > - if (ret < 0) > - pr_warn("register_cpu %d failed (%d)\n", cpu, ret); > - > - return ret; > + c->hotpluggable = !io_master(cpu); > + return register_cpu(c, cpu); > } > EXPORT_SYMBOL(arch_register_cpu); > > @@ -33,21 +26,3 @@ void arch_unregister_cpu(int cpu) > } > EXPORT_SYMBOL(arch_unregister_cpu); > #endif > - > -static int __init topology_init(void) > -{ > - int i, ret; > - > - for_each_present_cpu(i) { > - struct cpu *c = &per_cpu(cpu_devices, i); > - > - c->hotpluggable = !io_master(i); > - ret = register_cpu(c, i); > - if (ret < 0) > - pr_warn("topology_init: register_cpu %d failed (%d)\n", i, ret); > - } > - > - return 0; > -} > - > -subsys_initcall(topology_init);