From patchwork Tue Oct 24 15:17:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Russell King (Oracle)" X-Patchwork-Id: 13434828 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 7AEAEC25B48 for ; Tue, 24 Oct 2023 15:19:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343713AbjJXPT2 (ORCPT ); Tue, 24 Oct 2023 11:19:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343740AbjJXPSz (ORCPT ); Tue, 24 Oct 2023 11:18:55 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0AB5C19A5; Tue, 24 Oct 2023 08:17:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Date:Sender:Message-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References: In-Reply-To:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=XGhpKk09pdERl3TLuSkcjp8wddtxgCnM/F8wNa+d4Ds=; b=BaRzQs9RvF3vLCxNwFRxtjE6ks wG2NaWwkOXyUT2VHE/A3pWr8BxpYPLcrVCvY7kZ8127m2eL2srXo4sXT7vfm30D5MBa/Bw1gIh1hD v9aK0QW1Gfhj89CyI+h0062CIXcrogZdeY5hrauhc8Ep5dLRrMsSDBLjZwqa9uOI00kgtTDaXWyJ/ Cs/eEoRzj/niuEj9vq34jJwjfsrdLFMkKMbHbKWilyR5CO6KkvKlUabW/kgmZff9YrW8EeJJWVAMX HxcW7NNOFovYMbqcpXDvqlfORQ00w00zpq6D/oEnhIchOBNNPRAw5GSIm3ujZTIICK23YJBZ3lrLZ pW687WYA==; Received: from e0022681537dd.dyn.armlinux.org.uk ([fd8f:7570:feb6:1:222:68ff:fe15:37dd]:33446 helo=rmk-PC.armlinux.org.uk) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1qvJ9z-0004Ql-0y; Tue, 24 Oct 2023 16:17:35 +0100 Received: from rmk by rmk-PC.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1qvJA0-00AqQU-Or; Tue, 24 Oct 2023 16:17:36 +0100 In-Reply-To: References: From: Russell King (Oracle) To: linux-pm@vger.kernel.org, loongarch@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev, x86@kernel.org, linux-csky@vger.kernel.org, linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org Cc: Salil Mehta , Jean-Philippe Brucker , jianyong.wu@arm.com, justin.he@arm.com, James Morse , Sudeep Holla , Greg Kroah-Hartman , "Rafael J. Wysocki" Subject: [PATCH 17/39] arch_topology: Make register_cpu_capacity_sysctl() tolerant to late CPUs MIME-Version: 1.0 Content-Disposition: inline Message-Id: Sender: Russell King Date: Tue, 24 Oct 2023 16:17:36 +0100 Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org From: James Morse register_cpu_capacity_sysctl() adds a property to sysfs that describes the CPUs capacity. This is done from a subsys_initcall() that assumes all possible CPUs are registered. With CPU hotplug, possible CPUs aren't registered until they become present, (or for arm64 enabled). This leads to messages during boot: | register_cpu_capacity_sysctl: too early to get CPU1 device! and once these CPUs are added to the system, the file is missing. Move this to a cpuhp callback, so that the file is created once CPUs are brought online. This covers CPUs that are added late by mechanisms like hotplug. One observable difference is the file is now missing for offline CPUs. Signed-off-by: James Morse --- If the offline CPUs thing is a problem for the tools that consume this value, we'd need to move cpu_capacity to be part of cpu.c's common_cpu_attr_groups. --- drivers/base/arch_topology.c | 38 ++++++++++++++++++++++++------------ 1 file changed, 26 insertions(+), 12 deletions(-) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index b741b5ba82bd..9ccb7daee78e 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -220,20 +220,34 @@ static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn); static DEVICE_ATTR_RO(cpu_capacity); -static int register_cpu_capacity_sysctl(void) +static int cpu_capacity_sysctl_add(unsigned int cpu) { - int i; - struct device *cpu; + struct device *cpu_dev = get_cpu_device(cpu); - for_each_possible_cpu(i) { - cpu = get_cpu_device(i); - if (!cpu) { - pr_err("%s: too early to get CPU%d device!\n", - __func__, i); - continue; - } - device_create_file(cpu, &dev_attr_cpu_capacity); - } + if (!cpu_dev) + return -ENOENT; + + device_create_file(cpu_dev, &dev_attr_cpu_capacity); + + return 0; +} + +static int cpu_capacity_sysctl_remove(unsigned int cpu) +{ + struct device *cpu_dev = get_cpu_device(cpu); + + if (!cpu_dev) + return -ENOENT; + + device_remove_file(cpu_dev, &dev_attr_cpu_capacity); + + return 0; +} + +static int register_cpu_capacity_sysctl(void) +{ + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "topology/cpu-capacity", + cpu_capacity_sysctl_add, cpu_capacity_sysctl_remove); return 0; }