From 98f8cdce1db580b99fce823a48eea2cb2bdb261e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 26 Feb 2016 18:43:31 +0000 Subject: [PATCH] cpu/hotplug: Add sysfs state interface Add a sysfs interface so we can actually see in which state the cpus are in. Signed-off-by: Thomas Gleixner Cc: linux-arch@vger.kernel.org Cc: Rik van Riel Cc: Rafael Wysocki Cc: "Srivatsa S. Bhat" Cc: Peter Zijlstra Cc: Arjan van de Ven Cc: Sebastian Siewior Cc: Rusty Russell Cc: Steven Rostedt Cc: Oleg Nesterov Cc: Tejun Heo Cc: Andrew Morton Cc: Paul McKenney Cc: Linus Torvalds Cc: Paul Turner Link: http://lkml.kernel.org/r/20160226182340.942257522@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/cpu.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) diff --git a/kernel/cpu.c b/kernel/cpu.c index a00f8f67e4ad..1979b8927b86 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -56,6 +56,7 @@ struct cpuhp_step { bool skip_onerr; }; +static DEFINE_MUTEX(cpuhp_state_mutex); static struct cpuhp_step cpuhp_bp_states[]; static struct cpuhp_step cpuhp_ap_states[]; @@ -955,6 +956,105 @@ static struct cpuhp_step cpuhp_ap_states[] = { }, }; +static bool cpuhp_is_ap_state(enum cpuhp_state state) +{ + return (state > CPUHP_AP_OFFLINE && state < CPUHP_AP_ONLINE); +} + +static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) +{ + struct cpuhp_step *sp; + + sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; + return sp + state; +} + +#if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) +static ssize_t show_cpuhp_state(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); + + return sprintf(buf, "%d\n", st->state); +} +static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); + +static ssize_t show_cpuhp_target(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); + + return sprintf(buf, "%d\n", st->target); +} +static DEVICE_ATTR(target, 0444, show_cpuhp_target, NULL); + +static struct attribute *cpuhp_cpu_attrs[] = { + &dev_attr_state.attr, + &dev_attr_target.attr, + NULL +}; + +static struct attribute_group cpuhp_cpu_attr_group = { + .attrs = cpuhp_cpu_attrs, + .name = "hotplug", + NULL +}; + +static ssize_t show_cpuhp_states(struct device *dev, + struct device_attribute *attr, char *buf) +{ + ssize_t cur, res = 0; + int i; + + mutex_lock(&cpuhp_state_mutex); + for (i = 0; i <= CPUHP_ONLINE; i++) { + struct cpuhp_step *sp = cpuhp_get_step(i); + + if (sp->name) { + cur = sprintf(buf, "%3d: %s\n", i, sp->name); + buf += cur; + res += cur; + } + } + mutex_unlock(&cpuhp_state_mutex); + return res; +} +static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); + +static struct attribute *cpuhp_cpu_root_attrs[] = { + &dev_attr_states.attr, + NULL +}; + +static struct attribute_group cpuhp_cpu_root_attr_group = { + .attrs = cpuhp_cpu_root_attrs, + .name = "hotplug", + NULL +}; + +static int __init cpuhp_sysfs_init(void) +{ + int cpu, ret; + + ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, + &cpuhp_cpu_root_attr_group); + if (ret) + return ret; + + for_each_possible_cpu(cpu) { + struct device *dev = get_cpu_device(cpu); + + if (!dev) + continue; + ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); + if (ret) + return ret; + } + return 0; +} +device_initcall(cpuhp_sysfs_init); +#endif + /* * cpu_bit_bitmap[] is a special, "compressed" data structure that * represents all NR_CPUS bits binary values of 1<