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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 2D9A3C4360F for ; Tue, 2 Apr 2019 10:40:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E84F5208E4 for ; Tue, 2 Apr 2019 10:40:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729580AbfDBKkW (ORCPT ); Tue, 2 Apr 2019 06:40:22 -0400 Received: from terminus.zytor.com ([198.137.202.136]:39691 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729030AbfDBKkW (ORCPT ); Tue, 2 Apr 2019 06:40:22 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x32Ae6A31349978 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 2 Apr 2019 03:40:06 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x32Ae6ia1349974; Tue, 2 Apr 2019 03:40:06 -0700 Date: Tue, 2 Apr 2019 03:40:06 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Josh Poimboeuf Message-ID: Cc: aarcange@redhat.com, hpa@zytor.com, tglx@linutronix.de, jpoimboe@redhat.com, mingo@kernel.org, jikos@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, longman@redhat.com Reply-To: jikos@kernel.org, peterz@infradead.org, mingo@kernel.org, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, longman@redhat.com, aarcange@redhat.com, tglx@linutronix.de, hpa@zytor.com In-Reply-To: <469c2b98055f2c41e75748e06447d592a64080c9.1553635520.git.jpoimboe@redhat.com> References: <469c2b98055f2c41e75748e06447d592a64080c9.1553635520.git.jpoimboe@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:smp/hotplug] cpu/hotplug: Create SMT sysfs interface for all arches Git-Commit-ID: de7b77e5bb9451417ca57f1b6501da654587c048 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: de7b77e5bb9451417ca57f1b6501da654587c048 Gitweb: https://git.kernel.org/tip/de7b77e5bb9451417ca57f1b6501da654587c048 Author: Josh Poimboeuf AuthorDate: Wed, 27 Mar 2019 07:00:29 -0500 Committer: Thomas Gleixner CommitDate: Tue, 2 Apr 2019 12:36:56 +0200 cpu/hotplug: Create SMT sysfs interface for all arches Make the /sys/devices/system/cpu/smt/* files available on all arches, so user space has a consistent way to detect whether SMT is enabled. The 'control' file now shows 'notimplemented' for architectures which don't yet have CONFIG_HOTPLUG_SMT. [ tglx: Make notimplemented a real state ] Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Cc: Andrea Arcangeli Cc: Waiman Long Cc: Peter Zijlstra Cc: Jiri Kosina Link: https://lkml.kernel.org/r/469c2b98055f2c41e75748e06447d592a64080c9.1553635520.git.jpoimboe@redhat.com --- Documentation/ABI/testing/sysfs-devices-system-cpu | 10 ++-- include/linux/cpu.h | 3 +- kernel/cpu.c | 64 +++++++++++++--------- 3 files changed, 47 insertions(+), 30 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 9605dbd4b5b5..5eea46fefcb2 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -511,10 +511,12 @@ Description: Control Symetric Multi Threading (SMT) control: Read/write interface to control SMT. Possible values: - "on" SMT is enabled - "off" SMT is disabled - "forceoff" SMT is force disabled. Cannot be changed. - "notsupported" SMT is not supported by the CPU + "on" SMT is enabled + "off" SMT is disabled + "forceoff" SMT is force disabled. Cannot be changed. + "notsupported" SMT is not supported by the CPU + "notimplemented" SMT runtime toggling is not + implemented for the architecture If control status is "forceoff" or "notsupported" writes are rejected. diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 5041357d0297..ae99dde02320 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -175,6 +175,7 @@ enum cpuhp_smt_control { CPU_SMT_DISABLED, CPU_SMT_FORCE_DISABLED, CPU_SMT_NOT_SUPPORTED, + CPU_SMT_NOT_IMPLEMENTED, }; #if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT) @@ -182,7 +183,7 @@ extern enum cpuhp_smt_control cpu_smt_control; extern void cpu_smt_disable(bool force); extern void cpu_smt_check_topology(void); #else -# define cpu_smt_control (CPU_SMT_ENABLED) +# define cpu_smt_control (CPU_SMT_NOT_IMPLEMENTED) static inline void cpu_smt_disable(bool force) { } static inline void cpu_smt_check_topology(void) { } #endif diff --git a/kernel/cpu.c b/kernel/cpu.c index 6754f3ecfd94..b8bf3f93e39b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -2033,19 +2033,6 @@ static const struct attribute_group cpuhp_cpu_root_attr_group = { #ifdef CONFIG_HOTPLUG_SMT -static const char *smt_states[] = { - [CPU_SMT_ENABLED] = "on", - [CPU_SMT_DISABLED] = "off", - [CPU_SMT_FORCE_DISABLED] = "forceoff", - [CPU_SMT_NOT_SUPPORTED] = "notsupported", -}; - -static ssize_t -show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) -{ - return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); -} - static void cpuhp_offline_cpu_device(unsigned int cpu) { struct device *dev = get_cpu_device(cpu); @@ -2116,9 +2103,10 @@ static int cpuhp_smt_enable(void) return ret; } + static ssize_t -store_smt_control(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) +__store_smt_control(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) { int ctrlval, ret; @@ -2156,14 +2144,44 @@ store_smt_control(struct device *dev, struct device_attribute *attr, unlock_device_hotplug(); return ret ? ret : count; } + +#else /* !CONFIG_HOTPLUG_SMT */ +static ssize_t +__store_smt_control(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + return -ENODEV; +} +#endif /* CONFIG_HOTPLUG_SMT */ + +static const char *smt_states[] = { + [CPU_SMT_ENABLED] = "on", + [CPU_SMT_DISABLED] = "off", + [CPU_SMT_FORCE_DISABLED] = "forceoff", + [CPU_SMT_NOT_SUPPORTED] = "notsupported", + [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", +}; + +static ssize_t +show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) +{ + const char *state = smt_states[cpu_smt_control]; + + return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); +} + +static ssize_t +store_smt_control(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + return __store_smt_control(dev, attr, buf, count); +} static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); static ssize_t show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) { - bool active = topology_max_smt_threads() > 1; - - return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); + return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); } static DEVICE_ATTR(active, 0444, show_smt_active, NULL); @@ -2179,21 +2197,17 @@ static const struct attribute_group cpuhp_smt_attr_group = { NULL }; -static int __init cpu_smt_state_init(void) +static int __init cpu_smt_sysfs_init(void) { return sysfs_create_group(&cpu_subsys.dev_root->kobj, &cpuhp_smt_attr_group); } -#else -static inline int cpu_smt_state_init(void) { return 0; } -#endif - static int __init cpuhp_sysfs_init(void) { int cpu, ret; - ret = cpu_smt_state_init(); + ret = cpu_smt_sysfs_init(); if (ret) return ret; @@ -2214,7 +2228,7 @@ static int __init cpuhp_sysfs_init(void) return 0; } device_initcall(cpuhp_sysfs_init); -#endif +#endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ /* * cpu_bit_bitmap[] is a special, "compressed" data structure that