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debug percpu ref 

Signed-off-by: Wenchao Hao <haowenchao@huawei.com>
This commit is contained in:
Wenchao Hao 2023-04-20 16:58:58 +08:00
parent d88fefbbbb
commit c4dd3f468a
1 changed files with 40 additions and 50 deletions
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90
kobject-example.c
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@ -3,82 +3,72 @@
#include <linux/sysfs.h> #include <linux/sysfs.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/init.h> #include <linux/init.h>
#include <linux/percpu-refcount.h>
static int foo; static struct kobject *example_kobj;
static int baz; static struct percpu_ref global_ref;
static int bar;
static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr, static void global_ref_release(struct percpu_ref *)
{
printk("%s %d\n", __func__, __LINE__);
}
static ssize_t is_percpu_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf) char *buf)
{ {
return sysfs_emit(buf, "%d\n", foo); unsigned long __percpu *percpu_count;
return sysfs_emit(buf, "%d\n", __ref_is_percpu(&global_ref, &percpu_count));
} }
static struct kobj_attribute is_percpu_attribute = __ATTR_RO(is_percpu);
static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr, static ssize_t is_dying_show(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count) char *buf)
{ {
int ret; return sysfs_emit(buf, "%d\n", percpu_ref_is_dying(&global_ref));
ret = kstrtoint(buf, 10, &foo);
if (ret < 0)
return ret;
return count;
} }
static struct kobj_attribute is_dying_attribute = __ATTR_RO(is_dying);
static struct kobj_attribute foo_attribute = static ssize_t is_zero_show(struct kobject *kobj, struct kobj_attribute *attr,
__ATTR(foo, 0664, foo_show, foo_store); char *buf)
static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{ {
int var; return sysfs_emit(buf, "%d\n", percpu_ref_is_zero(&global_ref));
if (strcmp(attr->attr.name, "baz") == 0)
var = baz;
else
var = bar;
return sysfs_emit(buf, "%d\n", var);
} }
static struct kobj_attribute is_zero_attribute = __ATTR_RO(is_zero);
static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr, static ssize_t kill_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count) const char *buf, size_t count)
{ {
int var, ret; percpu_ref_kill(&global_ref);
return count;
ret = kstrtoint(buf, 10, &var);
if (ret < 0)
return ret;
if (strcmp(attr->attr.name, "baz") == 0)
baz = var;
else
bar = var;
return count;
} }
static struct kobj_attribute kill_attribute = __ATTR_WO(kill);
static struct kobj_attribute baz_attribute = static ssize_t resurrect_store(struct kobject *kobj, struct kobj_attribute *attr,
__ATTR(baz, 0664, b_show, b_store); const char *buf, size_t count)
static struct kobj_attribute bar_attribute = {
__ATTR(bar, 0664, b_show, b_store); percpu_ref_resurrect(&global_ref);
return count;
}
static struct kobj_attribute resurrect_attribute = __ATTR_WO(resurrect);
static struct attribute *attrs[] = { static struct attribute *attrs[] = {
&foo_attribute.attr, &is_dying_attribute.attr,
&baz_attribute.attr, &is_zero_attribute.attr,
&bar_attribute.attr, &is_percpu_attribute.attr,
NULL, /* need to NULL terminate the list of attributes */ &kill_attribute.attr,
&resurrect_attribute.attr,
NULL,
}; };
static struct attribute_group attr_group = { static struct attribute_group attr_group = {
.attrs = attrs, .attrs = attrs,
}; };
static struct kobject *example_kobj;
static int __init example_init(void) static int __init example_init(void)
{ {
int retval; int retval;
retval = percpu_ref_init(&global_ref, global_ref_release, PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
example_kobj = kobject_create_and_add("kobject_example", kernel_kobj); example_kobj = kobject_create_and_add("kobject_example", kernel_kobj);
if (!example_kobj) if (!example_kobj)
return -ENOMEM; return -ENOMEM;