1 #ifdef CONFIG_SCHED_AUTOGROUP
3 #include <linux/proc_fs.h>
4 #include <linux/seq_file.h>
5 #include <linux/kallsyms.h>
6 #include <linux/utsname.h>
8 unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
9 static struct autogroup autogroup_default;
10 static atomic_t autogroup_seq_nr;
12 static void autogroup_init(struct task_struct *init_task)
14 autogroup_default.tg = &init_task_group;
15 init_task_group.autogroup = &autogroup_default;
16 kref_init(&autogroup_default.kref);
17 init_rwsem(&autogroup_default.lock);
18 init_task->signal->autogroup = &autogroup_default;
21 static inline void autogroup_free(struct task_group *tg)
26 static inline void autogroup_destroy(struct kref *kref)
28 struct autogroup *ag = container_of(kref, struct autogroup, kref);
30 sched_destroy_group(ag->tg);
33 static inline void autogroup_kref_put(struct autogroup *ag)
35 kref_put(&ag->kref, autogroup_destroy);
38 static inline struct autogroup *autogroup_kref_get(struct autogroup *ag)
44 static inline struct autogroup *autogroup_create(void)
46 struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
47 struct task_group *tg;
52 tg = sched_create_group(&init_task_group);
58 init_rwsem(&ag->lock);
59 ag->id = atomic_inc_return(&autogroup_seq_nr);
68 if (printk_ratelimit()) {
69 printk(KERN_WARNING "autogroup_create: %s failure.\n",
70 ag ? "sched_create_group()" : "kmalloc()");
73 return autogroup_kref_get(&autogroup_default);
77 task_wants_autogroup(struct task_struct *p, struct task_group *tg)
79 if (tg != &root_task_group)
82 if (p->sched_class != &fair_sched_class)
86 * We can only assume the task group can't go away on us if
87 * autogroup_move_group() can see us on ->thread_group list.
89 if (p->flags & PF_EXITING)
95 static inline struct task_group *
96 autogroup_task_group(struct task_struct *p, struct task_group *tg)
98 int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
100 if (enabled && task_wants_autogroup(p, tg))
101 return p->signal->autogroup->tg;
107 autogroup_move_group(struct task_struct *p, struct autogroup *ag)
109 struct autogroup *prev;
110 struct task_struct *t;
113 BUG_ON(!lock_task_sighand(p, &flags));
115 prev = p->signal->autogroup;
117 unlock_task_sighand(p, &flags);
121 p->signal->autogroup = autogroup_kref_get(ag);
126 } while_each_thread(p, t);
128 unlock_task_sighand(p, &flags);
129 autogroup_kref_put(prev);
132 /* Allocates GFP_KERNEL, cannot be called under any spinlock */
133 void sched_autogroup_create_attach(struct task_struct *p)
135 struct autogroup *ag = autogroup_create();
137 autogroup_move_group(p, ag);
138 /* drop extra refrence added by autogroup_create() */
139 autogroup_kref_put(ag);
141 EXPORT_SYMBOL(sched_autogroup_create_attach);
143 /* Cannot be called under siglock. Currently has no users */
144 void sched_autogroup_detach(struct task_struct *p)
146 autogroup_move_group(p, &autogroup_default);
148 EXPORT_SYMBOL(sched_autogroup_detach);
150 void sched_autogroup_fork(struct signal_struct *sig)
152 struct task_struct *p = current;
154 spin_lock_irq(&p->sighand->siglock);
155 sig->autogroup = autogroup_kref_get(p->signal->autogroup);
156 spin_unlock_irq(&p->sighand->siglock);
159 void sched_autogroup_exit(struct signal_struct *sig)
161 autogroup_kref_put(sig->autogroup);
164 static int __init setup_autogroup(char *str)
166 sysctl_sched_autogroup_enabled = 0;
171 __setup("noautogroup", setup_autogroup);
173 #ifdef CONFIG_PROC_FS
175 /* Called with siglock held. */
176 int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice)
178 static unsigned long next = INITIAL_JIFFIES;
179 struct autogroup *ag;
182 if (*nice < -20 || *nice > 19)
185 err = security_task_setnice(current, *nice);
189 if (*nice < 0 && !can_nice(current, *nice))
192 /* this is a heavy operation taking global locks.. */
193 if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
196 next = HZ / 10 + jiffies;
197 ag = autogroup_kref_get(p->signal->autogroup);
199 down_write(&ag->lock);
200 err = sched_group_set_shares(ag->tg, prio_to_weight[*nice + 20]);
205 autogroup_kref_put(ag);
210 void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
212 struct autogroup *ag = autogroup_kref_get(p->signal->autogroup);
214 down_read(&ag->lock);
215 seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
218 autogroup_kref_put(ag);
220 #endif /* CONFIG_PROC_FS */
222 #ifdef CONFIG_SCHED_DEBUG
223 static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
225 return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
227 #endif /* CONFIG_SCHED_DEBUG */
229 #endif /* CONFIG_SCHED_AUTOGROUP */