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Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull CPU hotplug updates from Ingo Molnar:
 "Two changes in this cycle:

   - 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.

   - Sparse annotation fix"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smpboot: Place the __percpu annotation correctly
  cpu/hotplug: Create SMT sysfs interface for all arches
This commit is contained in:
Linus Torvalds
2019-05-06 14:44:49 -07:00
parent e00d413575 d4645d30b5
commit 5a2bf1abbf
4 changed files with 48 additions and 31 deletions
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64
kernel/cpu.c
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@@ -2041,19 +2041,6 @@ 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);
@@ -2124,9 +2111,10 @@ 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;
@@ -2164,14 +2152,44 @@ 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);
@@ -2187,21 +2205,17 @@ 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;
@@ -2222,7 +2236,7 @@ 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