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 __init autogroup_init(struct task_struct *init_task)
14 autogroup_default.tg = &root_task_group;
15 kref_init(&autogroup_default.kref);
16 init_rwsem(&autogroup_default.lock);
17 init_task->signal->autogroup = &autogroup_default;
20 static inline void autogroup_free(struct task_group *tg)
25 static inline void autogroup_destroy(struct kref *kref)
27 struct autogroup *ag = container_of(kref, struct autogroup, kref);
29 #ifdef CONFIG_RT_GROUP_SCHED
30 /* We've redirected RT tasks to the root task group... */
34 sched_destroy_group(ag->tg);
37 static inline void autogroup_kref_put(struct autogroup *ag)
39 kref_put(&ag->kref, autogroup_destroy);
42 static inline struct autogroup *autogroup_kref_get(struct autogroup *ag)
48 static inline struct autogroup *autogroup_task_get(struct task_struct *p)
53 if (!lock_task_sighand(p, &flags))
54 return autogroup_kref_get(&autogroup_default);
56 ag = autogroup_kref_get(p->signal->autogroup);
57 unlock_task_sighand(p, &flags);
62 #ifdef CONFIG_RT_GROUP_SCHED
63 static void free_rt_sched_group(struct task_group *tg);
66 static inline struct autogroup *autogroup_create(void)
68 struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL);
69 struct task_group *tg;
74 tg = sched_create_group(&root_task_group);
80 init_rwsem(&ag->lock);
81 ag->id = atomic_inc_return(&autogroup_seq_nr);
83 #ifdef CONFIG_RT_GROUP_SCHED
85 * Autogroup RT tasks are redirected to the root task group
86 * so we don't have to move tasks around upon policy change,
87 * or flail around trying to allocate bandwidth on the fly.
88 * A bandwidth exception in __sched_setscheduler() allows
89 * the policy change to proceed.
91 free_rt_sched_group(tg);
92 tg->rt_se = root_task_group.rt_se;
93 tg->rt_rq = root_task_group.rt_rq;
102 if (printk_ratelimit()) {
103 printk(KERN_WARNING "autogroup_create: %s failure.\n",
104 ag ? "sched_create_group()" : "kmalloc()");
107 return autogroup_kref_get(&autogroup_default);
111 task_wants_autogroup(struct task_struct *p, struct task_group *tg)
113 if (tg != &root_task_group)
117 * We can only assume the task group can't go away on us if
118 * autogroup_move_group() can see us on ->thread_group list.
120 if (p->flags & PF_EXITING)
126 static inline bool task_group_is_autogroup(struct task_group *tg)
128 return !!tg->autogroup;
131 static inline struct task_group *
132 autogroup_task_group(struct task_struct *p, struct task_group *tg)
134 int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
136 if (enabled && task_wants_autogroup(p, tg))
137 return p->signal->autogroup->tg;
143 autogroup_move_group(struct task_struct *p, struct autogroup *ag)
145 struct autogroup *prev;
146 struct task_struct *t;
149 BUG_ON(!lock_task_sighand(p, &flags));
151 prev = p->signal->autogroup;
153 unlock_task_sighand(p, &flags);
157 p->signal->autogroup = autogroup_kref_get(ag);
162 } while_each_thread(p, t);
164 unlock_task_sighand(p, &flags);
165 autogroup_kref_put(prev);
168 /* Allocates GFP_KERNEL, cannot be called under any spinlock */
169 void sched_autogroup_create_attach(struct task_struct *p)
171 struct autogroup *ag = autogroup_create();
173 autogroup_move_group(p, ag);
174 /* drop extra reference added by autogroup_create() */
175 autogroup_kref_put(ag);
177 EXPORT_SYMBOL(sched_autogroup_create_attach);
179 /* Cannot be called under siglock. Currently has no users */
180 void sched_autogroup_detach(struct task_struct *p)
182 autogroup_move_group(p, &autogroup_default);
184 EXPORT_SYMBOL(sched_autogroup_detach);
186 void sched_autogroup_fork(struct signal_struct *sig)
188 sig->autogroup = autogroup_task_get(current);
191 void sched_autogroup_exit(struct signal_struct *sig)
193 autogroup_kref_put(sig->autogroup);
196 static int __init setup_autogroup(char *str)
198 sysctl_sched_autogroup_enabled = 0;
203 __setup("noautogroup", setup_autogroup);
205 #ifdef CONFIG_PROC_FS
207 int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice)
209 static unsigned long next = INITIAL_JIFFIES;
210 struct autogroup *ag;
213 if (*nice < -20 || *nice > 19)
216 err = security_task_setnice(current, *nice);
220 if (*nice < 0 && !can_nice(current, *nice))
223 /* this is a heavy operation taking global locks.. */
224 if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))
227 next = HZ / 10 + jiffies;
228 ag = autogroup_task_get(p);
230 down_write(&ag->lock);
231 err = sched_group_set_shares(ag->tg, prio_to_weight[*nice + 20]);
236 autogroup_kref_put(ag);
241 void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
243 struct autogroup *ag = autogroup_task_get(p);
245 if (!task_group_is_autogroup(ag->tg))
248 down_read(&ag->lock);
249 seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
253 autogroup_kref_put(ag);
255 #endif /* CONFIG_PROC_FS */
257 #ifdef CONFIG_SCHED_DEBUG
258 static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
260 if (!task_group_is_autogroup(tg))
263 return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
265 #endif /* CONFIG_SCHED_DEBUG */
267 #endif /* CONFIG_SCHED_AUTOGROUP */