5cb350baf5
Add tunables in sysfs to modify a user's cpu share. A directory is created in sysfs for each new user in the system. /sys/kernel/uids/<uid>/cpu_share Reading this file returns the cpu shares granted for the user. Writing into this file modifies the cpu share for the user. Only an administrator is allowed to modify a user's cpu share. Ex: # cd /sys/kernel/uids/ # cat 512/cpu_share 1024 # echo 2048 > 512/cpu_share # cat 512/cpu_share 2048 # Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
131 lines
3.2 KiB
C
131 lines
3.2 KiB
C
/*
|
|
* kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
|
|
* are not related to any other subsystem
|
|
*
|
|
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
|
|
*
|
|
* This file is release under the GPLv2
|
|
*
|
|
*/
|
|
|
|
#include <linux/kobject.h>
|
|
#include <linux/string.h>
|
|
#include <linux/sysfs.h>
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kexec.h>
|
|
#include <linux/sched.h>
|
|
|
|
#define KERNEL_ATTR_RO(_name) \
|
|
static struct subsys_attribute _name##_attr = __ATTR_RO(_name)
|
|
|
|
#define KERNEL_ATTR_RW(_name) \
|
|
static struct subsys_attribute _name##_attr = \
|
|
__ATTR(_name, 0644, _name##_show, _name##_store)
|
|
|
|
#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
|
|
/* current uevent sequence number */
|
|
static ssize_t uevent_seqnum_show(struct kset *kset, char *page)
|
|
{
|
|
return sprintf(page, "%llu\n", (unsigned long long)uevent_seqnum);
|
|
}
|
|
KERNEL_ATTR_RO(uevent_seqnum);
|
|
|
|
/* uevent helper program, used during early boo */
|
|
static ssize_t uevent_helper_show(struct kset *kset, char *page)
|
|
{
|
|
return sprintf(page, "%s\n", uevent_helper);
|
|
}
|
|
static ssize_t uevent_helper_store(struct kset *kset, const char *page, size_t count)
|
|
{
|
|
if (count+1 > UEVENT_HELPER_PATH_LEN)
|
|
return -ENOENT;
|
|
memcpy(uevent_helper, page, count);
|
|
uevent_helper[count] = '\0';
|
|
if (count && uevent_helper[count-1] == '\n')
|
|
uevent_helper[count-1] = '\0';
|
|
return count;
|
|
}
|
|
KERNEL_ATTR_RW(uevent_helper);
|
|
#endif
|
|
|
|
#ifdef CONFIG_KEXEC
|
|
static ssize_t kexec_loaded_show(struct kset *kset, char *page)
|
|
{
|
|
return sprintf(page, "%d\n", !!kexec_image);
|
|
}
|
|
KERNEL_ATTR_RO(kexec_loaded);
|
|
|
|
static ssize_t kexec_crash_loaded_show(struct kset *kset, char *page)
|
|
{
|
|
return sprintf(page, "%d\n", !!kexec_crash_image);
|
|
}
|
|
KERNEL_ATTR_RO(kexec_crash_loaded);
|
|
#endif /* CONFIG_KEXEC */
|
|
|
|
/*
|
|
* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
|
|
*/
|
|
extern const void __start_notes __attribute__((weak));
|
|
extern const void __stop_notes __attribute__((weak));
|
|
#define notes_size (&__stop_notes - &__start_notes)
|
|
|
|
static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
|
|
char *buf, loff_t off, size_t count)
|
|
{
|
|
memcpy(buf, &__start_notes + off, count);
|
|
return count;
|
|
}
|
|
|
|
static struct bin_attribute notes_attr = {
|
|
.attr = {
|
|
.name = "notes",
|
|
.mode = S_IRUGO,
|
|
},
|
|
.read = ¬es_read,
|
|
};
|
|
|
|
decl_subsys(kernel, NULL, NULL);
|
|
EXPORT_SYMBOL_GPL(kernel_subsys);
|
|
|
|
static struct attribute * kernel_attrs[] = {
|
|
#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
|
|
&uevent_seqnum_attr.attr,
|
|
&uevent_helper_attr.attr,
|
|
#endif
|
|
#ifdef CONFIG_KEXEC
|
|
&kexec_loaded_attr.attr,
|
|
&kexec_crash_loaded_attr.attr,
|
|
#endif
|
|
NULL
|
|
};
|
|
|
|
static struct attribute_group kernel_attr_group = {
|
|
.attrs = kernel_attrs,
|
|
};
|
|
|
|
static int __init ksysfs_init(void)
|
|
{
|
|
int error = subsystem_register(&kernel_subsys);
|
|
if (!error)
|
|
error = sysfs_create_group(&kernel_subsys.kobj,
|
|
&kernel_attr_group);
|
|
|
|
if (!error && notes_size > 0) {
|
|
notes_attr.size = notes_size;
|
|
error = sysfs_create_bin_file(&kernel_subsys.kobj,
|
|
¬es_attr);
|
|
}
|
|
|
|
/*
|
|
* Create "/sys/kernel/uids" directory and corresponding root user's
|
|
* directory under it.
|
|
*/
|
|
if (!error)
|
|
error = uids_kobject_init();
|
|
|
|
return error;
|
|
}
|
|
|
|
core_initcall(ksysfs_init);
|