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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>
130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
/*
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* kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
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* are not related to any other subsystem
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*
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* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
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*
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* This file is release under the GPLv2
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*
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*/
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#include <linux/kobject.h>
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#include <linux/string.h>
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#include <linux/sysfs.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kexec.h>
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#include <linux/sched.h>
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#define KERNEL_ATTR_RO(_name) \
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static struct subsys_attribute _name##_attr = __ATTR_RO(_name)
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#define KERNEL_ATTR_RW(_name) \
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static struct subsys_attribute _name##_attr = \
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__ATTR(_name, 0644, _name##_show, _name##_store)
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#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
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/* current uevent sequence number */
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static ssize_t uevent_seqnum_show(struct kset *kset, char *page)
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{
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return sprintf(page, "%llu\n", (unsigned long long)uevent_seqnum);
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}
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KERNEL_ATTR_RO(uevent_seqnum);
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/* uevent helper program, used during early boo */
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static ssize_t uevent_helper_show(struct kset *kset, char *page)
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{
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return sprintf(page, "%s\n", uevent_helper);
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}
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static ssize_t uevent_helper_store(struct kset *kset, const char *page, size_t count)
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{
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if (count+1 > UEVENT_HELPER_PATH_LEN)
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return -ENOENT;
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memcpy(uevent_helper, page, count);
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uevent_helper[count] = '\0';
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if (count && uevent_helper[count-1] == '\n')
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uevent_helper[count-1] = '\0';
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return count;
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}
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KERNEL_ATTR_RW(uevent_helper);
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#endif
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#ifdef CONFIG_KEXEC
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static ssize_t kexec_loaded_show(struct kset *kset, char *page)
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{
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return sprintf(page, "%d\n", !!kexec_image);
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}
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KERNEL_ATTR_RO(kexec_loaded);
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static ssize_t kexec_crash_loaded_show(struct kset *kset, char *page)
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{
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return sprintf(page, "%d\n", !!kexec_crash_image);
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}
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KERNEL_ATTR_RO(kexec_crash_loaded);
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#endif /* CONFIG_KEXEC */
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/*
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* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
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*/
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extern const void __start_notes __attribute__((weak));
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extern const void __stop_notes __attribute__((weak));
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#define notes_size (&__stop_notes - &__start_notes)
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static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
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char *buf, loff_t off, size_t count)
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{
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memcpy(buf, &__start_notes + off, count);
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return count;
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}
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static struct bin_attribute notes_attr = {
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.attr = {
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.name = "notes",
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.mode = S_IRUGO,
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},
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.read = ¬es_read,
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};
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decl_subsys(kernel, NULL, NULL);
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EXPORT_SYMBOL_GPL(kernel_subsys);
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static struct attribute * kernel_attrs[] = {
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#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
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&uevent_seqnum_attr.attr,
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&uevent_helper_attr.attr,
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#endif
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#ifdef CONFIG_KEXEC
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&kexec_loaded_attr.attr,
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&kexec_crash_loaded_attr.attr,
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#endif
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NULL
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};
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static struct attribute_group kernel_attr_group = {
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.attrs = kernel_attrs,
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};
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static int __init ksysfs_init(void)
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{
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int error = subsystem_register(&kernel_subsys);
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if (!error)
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error = sysfs_create_group(&kernel_subsys.kobj,
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&kernel_attr_group);
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if (!error && notes_size > 0) {
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notes_attr.size = notes_size;
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error = sysfs_create_bin_file(&kernel_subsys.kobj,
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¬es_attr);
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}
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/*
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* Create "/sys/kernel/uids" directory and corresponding root user's
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* directory under it.
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*/
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if (!error)
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error = uids_kobject_init();
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return error;
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}
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core_initcall(ksysfs_init);
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