From patchwork Wed Jan 31 16:50:53 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Russell King (Oracle)" X-Patchwork-Id: 13539746 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0679B12C55A; Wed, 31 Jan 2024 16:56:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706720179; cv=none; b=HrXEo5bYsIjtPK7XL65dlP9HALb1/rDNYDsLHZdZ3r3WzCkz1ixUh9USilrXmOOuiL3+bS4E8CIUn9cni9S7iS1+oFpmNewIlJS+ENxNDJk1IqH0rp9y1nQpSRx6+sZeNIszcpbt/0XFcscoHgCMtKa+VoEV8ddwDQSQ6ZFAbW8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706720179; c=relaxed/simple; bh=EkVr8qkWgomRYpricd0zPmrR7pe29SgULm4sDGCbpQI=; h=In-Reply-To:References:From:To:Cc:Subject:MIME-Version: Content-Disposition:Content-Type:Message-Id:Date; b=GYtmFH4T037kcBqQJyUbFO26bxgccvubj7lhMcNeOHErPtxzXLw3aEIl7fvddEz+1xtm2vE2x+KrJA0RpfYzLXma90qRmaes/It1QY6RkTopCks0gr2v4SGTfB7HRJZgDJRH43m7PUMW1iSpSg56wG5B98EAyCQq2YkjXBigM9U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=1PtJggS5; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="1PtJggS5" 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=oPnhCwiKg9San/i05zV4ZOuN3WuOL1Uu7mhLCP64Beg=; b=1PtJggS59E8nf2Oup93oE/RTBA fNHpjJuukMuha+sNR7njHZomuyBzSzKwQnCbHdjp9pbY5a8v6hN+eVN4rIwfuIAAORdkLuKdkOAuD ERk+pMkhl5SuQqvlKstr/1XGTKUMDKLM+6zF2me6UftWm/dKNoXW0P1nQ+yyP9w7y8sC+t/d220Ow +mqd+JfKEKNPjEk8J8LdS+oDg82vrcUOxVTZio+4DFCv0LEEKeVRkv3Iv8e5bB6my+RMzPykq9RQa SMImavUzV2y1R1efsvLCJoTR3QoKzpsvUfcMD5AX/d+ApSjBnfVNQp9kDhCtwvrRtCdkbSkzQFW66 r8Rw/qRA==; Received: from e0022681537dd.dyn.armlinux.org.uk ([fd8f:7570:feb6:1:222:68ff:fe15:37dd]:38552 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 1rVDnb-0003Wp-09; Wed, 31 Jan 2024 16:50:55 +0000 Received: from rmk by rmk-PC.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1rVDnZ-0027Zl-Kr; Wed, 31 Jan 2024 16:50:53 +0000 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, acpica-devel@lists.linuxfoundation.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 , Jonathan Cameron , "Rafael J. Wysocki" Subject: [PATCH RFC v4 15/15] cpumask: Add enabled cpumask for present CPUs that can be brought online Precedence: bulk X-Mailing-List: linux-parisc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Message-Id: Sender: Russell King Date: Wed, 31 Jan 2024 16:50:53 +0000 From: James Morse The 'offline' file in sysfs shows all offline CPUs, including those that aren't present. User-space is expected to remove not-present CPUs from this list to learn which CPUs could be brought online. CPUs can be present but not-enabled. These CPUs can't be brought online until the firmware policy changes, which comes with an ACPI notification that will register the CPUs. With only the offline and present files, user-space is unable to determine which CPUs it can try to bring online. Add a new CPU mask that shows this based on all the registered CPUs. Signed-off-by: James Morse Tested-by: Miguel Luis Tested-by: Vishnu Pajjuri Tested-by: Jianyong Wu Acked-by: Thomas Gleixner Signed-off-by: Russell King (Oracle) --- Changes since RFCv3 (smaller series); * Added Documentation/ABI/testing/sysfs-devices-system-cpu entry --- .../ABI/testing/sysfs-devices-system-cpu | 6 +++++ drivers/base/cpu.c | 10 ++++++++ include/linux/cpumask.h | 25 +++++++++++++++++++ kernel/cpu.c | 3 +++ 4 files changed, 44 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index a1db6db47505..59482c10e0ad 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -693,3 +693,9 @@ Contact: Linux kernel mailing list (RO) indicates whether or not the kernel directly supports modifying the crash elfcorehdr for CPU hot un/plug and/or on/offline changes. + +What: /sys/devices/system/cpu/enabled +Date: Nov 2022 +Contact: Linux kernel mailing list +Description: + (RO) the list of CPUs that can be brought online. diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 13d052bf13f4..a6e96a0a92b7 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -95,6 +95,7 @@ void unregister_cpu(struct cpu *cpu) { int logical_cpu = cpu->dev.id; + set_cpu_enabled(logical_cpu, false); unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); device_unregister(&cpu->dev); @@ -273,6 +274,13 @@ static ssize_t print_cpus_offline(struct device *dev, } static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); +static ssize_t print_cpus_enabled(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(cpu_enabled_mask)); +} +static DEVICE_ATTR(enabled, 0444, print_cpus_enabled, NULL); + static ssize_t print_cpus_isolated(struct device *dev, struct device_attribute *attr, char *buf) { @@ -413,6 +421,7 @@ int register_cpu(struct cpu *cpu, int num) register_cpu_under_node(num, cpu_to_node(num)); dev_pm_qos_expose_latency_limit(&cpu->dev, PM_QOS_RESUME_LATENCY_NO_CONSTRAINT); + set_cpu_enabled(num, true); return 0; } @@ -494,6 +503,7 @@ static struct attribute *cpu_root_attrs[] = { &cpu_attrs[2].attr.attr, &dev_attr_kernel_max.attr, &dev_attr_offline.attr, + &dev_attr_enabled.attr, &dev_attr_isolated.attr, #ifdef CONFIG_NO_HZ_FULL &dev_attr_nohz_full.attr, diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index cfb545841a2c..cc72a0887f04 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -92,6 +92,7 @@ static inline void set_nr_cpu_ids(unsigned int nr) * * cpu_possible_mask- has bit 'cpu' set iff cpu is populatable * cpu_present_mask - has bit 'cpu' set iff cpu is populated + * cpu_enabled_mask - has bit 'cpu' set iff cpu can be brought online * cpu_online_mask - has bit 'cpu' set iff cpu available to scheduler * cpu_active_mask - has bit 'cpu' set iff cpu available to migration * @@ -124,11 +125,13 @@ static inline void set_nr_cpu_ids(unsigned int nr) extern struct cpumask __cpu_possible_mask; extern struct cpumask __cpu_online_mask; +extern struct cpumask __cpu_enabled_mask; extern struct cpumask __cpu_present_mask; extern struct cpumask __cpu_active_mask; extern struct cpumask __cpu_dying_mask; #define cpu_possible_mask ((const struct cpumask *)&__cpu_possible_mask) #define cpu_online_mask ((const struct cpumask *)&__cpu_online_mask) +#define cpu_enabled_mask ((const struct cpumask *)&__cpu_enabled_mask) #define cpu_present_mask ((const struct cpumask *)&__cpu_present_mask) #define cpu_active_mask ((const struct cpumask *)&__cpu_active_mask) #define cpu_dying_mask ((const struct cpumask *)&__cpu_dying_mask) @@ -993,6 +996,7 @@ extern const DECLARE_BITMAP(cpu_all_bits, NR_CPUS); #else #define for_each_possible_cpu(cpu) for_each_cpu((cpu), cpu_possible_mask) #define for_each_online_cpu(cpu) for_each_cpu((cpu), cpu_online_mask) +#define for_each_enabled_cpu(cpu) for_each_cpu((cpu), cpu_enabled_mask) #define for_each_present_cpu(cpu) for_each_cpu((cpu), cpu_present_mask) #endif @@ -1015,6 +1019,15 @@ set_cpu_possible(unsigned int cpu, bool possible) cpumask_clear_cpu(cpu, &__cpu_possible_mask); } +static inline void +set_cpu_enabled(unsigned int cpu, bool can_be_onlined) +{ + if (can_be_onlined) + cpumask_set_cpu(cpu, &__cpu_enabled_mask); + else + cpumask_clear_cpu(cpu, &__cpu_enabled_mask); +} + static inline void set_cpu_present(unsigned int cpu, bool present) { @@ -1096,6 +1109,7 @@ static __always_inline unsigned int num_online_cpus(void) return raw_atomic_read(&__num_online_cpus); } #define num_possible_cpus() cpumask_weight(cpu_possible_mask) +#define num_enabled_cpus() cpumask_weight(cpu_enabled_mask) #define num_present_cpus() cpumask_weight(cpu_present_mask) #define num_active_cpus() cpumask_weight(cpu_active_mask) @@ -1104,6 +1118,11 @@ static inline bool cpu_online(unsigned int cpu) return cpumask_test_cpu(cpu, cpu_online_mask); } +static inline bool cpu_enabled(unsigned int cpu) +{ + return cpumask_test_cpu(cpu, cpu_enabled_mask); +} + static inline bool cpu_possible(unsigned int cpu) { return cpumask_test_cpu(cpu, cpu_possible_mask); @@ -1128,6 +1147,7 @@ static inline bool cpu_dying(unsigned int cpu) #define num_online_cpus() 1U #define num_possible_cpus() 1U +#define num_enabled_cpus() 1U #define num_present_cpus() 1U #define num_active_cpus() 1U @@ -1141,6 +1161,11 @@ static inline bool cpu_possible(unsigned int cpu) return cpu == 0; } +static inline bool cpu_enabled(unsigned int cpu) +{ + return cpu == 0; +} + static inline bool cpu_present(unsigned int cpu) { return cpu == 0; diff --git a/kernel/cpu.c b/kernel/cpu.c index e6ec3ba4950b..23b5568fb378 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -3117,6 +3117,9 @@ EXPORT_SYMBOL(__cpu_possible_mask); struct cpumask __cpu_online_mask __read_mostly; EXPORT_SYMBOL(__cpu_online_mask); +struct cpumask __cpu_enabled_mask __read_mostly; +EXPORT_SYMBOL(__cpu_enabled_mask); + struct cpumask __cpu_present_mask __read_mostly; EXPORT_SYMBOL(__cpu_present_mask);