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5091faa4 MG |
1 | #ifdef CONFIG_SCHED_AUTOGROUP |
2 | ||
3 | #include <linux/proc_fs.h> | |
4 | #include <linux/seq_file.h> | |
5 | #include <linux/kallsyms.h> | |
6 | #include <linux/utsname.h> | |
7 | ||
8 | unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1; | |
9 | static struct autogroup autogroup_default; | |
10 | static atomic_t autogroup_seq_nr; | |
11 | ||
12 | static void autogroup_init(struct task_struct *init_task) | |
13 | { | |
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; | |
19 | } | |
20 | ||
21 | static inline void autogroup_free(struct task_group *tg) | |
22 | { | |
23 | kfree(tg->autogroup); | |
24 | } | |
25 | ||
26 | static inline void autogroup_destroy(struct kref *kref) | |
27 | { | |
28 | struct autogroup *ag = container_of(kref, struct autogroup, kref); | |
29 | ||
30 | sched_destroy_group(ag->tg); | |
31 | } | |
32 | ||
33 | static inline void autogroup_kref_put(struct autogroup *ag) | |
34 | { | |
35 | kref_put(&ag->kref, autogroup_destroy); | |
36 | } | |
37 | ||
38 | static inline struct autogroup *autogroup_kref_get(struct autogroup *ag) | |
39 | { | |
40 | kref_get(&ag->kref); | |
41 | return ag; | |
42 | } | |
43 | ||
4f821987 MG |
44 | static inline struct autogroup *autogroup_task_get(struct task_struct *p) |
45 | { | |
46 | struct autogroup *ag; | |
47 | unsigned long flags; | |
48 | ||
49 | if (!lock_task_sighand(p, &flags)) | |
50 | return autogroup_kref_get(&autogroup_default); | |
51 | ||
52 | ag = autogroup_kref_get(p->signal->autogroup); | |
53 | unlock_task_sighand(p, &flags); | |
54 | ||
55 | return ag; | |
56 | } | |
57 | ||
5091faa4 MG |
58 | static inline struct autogroup *autogroup_create(void) |
59 | { | |
60 | struct autogroup *ag = kzalloc(sizeof(*ag), GFP_KERNEL); | |
61 | struct task_group *tg; | |
62 | ||
63 | if (!ag) | |
64 | goto out_fail; | |
65 | ||
66 | tg = sched_create_group(&init_task_group); | |
67 | ||
68 | if (IS_ERR(tg)) | |
69 | goto out_free; | |
70 | ||
71 | kref_init(&ag->kref); | |
72 | init_rwsem(&ag->lock); | |
73 | ag->id = atomic_inc_return(&autogroup_seq_nr); | |
74 | ag->tg = tg; | |
75 | tg->autogroup = ag; | |
76 | ||
77 | return ag; | |
78 | ||
79 | out_free: | |
80 | kfree(ag); | |
81 | out_fail: | |
82 | if (printk_ratelimit()) { | |
83 | printk(KERN_WARNING "autogroup_create: %s failure.\n", | |
84 | ag ? "sched_create_group()" : "kmalloc()"); | |
85 | } | |
86 | ||
87 | return autogroup_kref_get(&autogroup_default); | |
88 | } | |
89 | ||
90 | static inline bool | |
91 | task_wants_autogroup(struct task_struct *p, struct task_group *tg) | |
92 | { | |
93 | if (tg != &root_task_group) | |
94 | return false; | |
95 | ||
96 | if (p->sched_class != &fair_sched_class) | |
97 | return false; | |
98 | ||
99 | /* | |
100 | * We can only assume the task group can't go away on us if | |
101 | * autogroup_move_group() can see us on ->thread_group list. | |
102 | */ | |
103 | if (p->flags & PF_EXITING) | |
104 | return false; | |
105 | ||
106 | return true; | |
107 | } | |
108 | ||
109 | static inline struct task_group * | |
110 | autogroup_task_group(struct task_struct *p, struct task_group *tg) | |
111 | { | |
112 | int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled); | |
113 | ||
114 | if (enabled && task_wants_autogroup(p, tg)) | |
115 | return p->signal->autogroup->tg; | |
116 | ||
117 | return tg; | |
118 | } | |
119 | ||
120 | static void | |
121 | autogroup_move_group(struct task_struct *p, struct autogroup *ag) | |
122 | { | |
123 | struct autogroup *prev; | |
124 | struct task_struct *t; | |
125 | unsigned long flags; | |
126 | ||
127 | BUG_ON(!lock_task_sighand(p, &flags)); | |
128 | ||
129 | prev = p->signal->autogroup; | |
130 | if (prev == ag) { | |
131 | unlock_task_sighand(p, &flags); | |
132 | return; | |
133 | } | |
134 | ||
135 | p->signal->autogroup = autogroup_kref_get(ag); | |
136 | ||
137 | t = p; | |
138 | do { | |
139 | sched_move_task(t); | |
140 | } while_each_thread(p, t); | |
141 | ||
142 | unlock_task_sighand(p, &flags); | |
143 | autogroup_kref_put(prev); | |
144 | } | |
145 | ||
146 | /* Allocates GFP_KERNEL, cannot be called under any spinlock */ | |
147 | void sched_autogroup_create_attach(struct task_struct *p) | |
148 | { | |
149 | struct autogroup *ag = autogroup_create(); | |
150 | ||
151 | autogroup_move_group(p, ag); | |
152 | /* drop extra refrence added by autogroup_create() */ | |
153 | autogroup_kref_put(ag); | |
154 | } | |
155 | EXPORT_SYMBOL(sched_autogroup_create_attach); | |
156 | ||
157 | /* Cannot be called under siglock. Currently has no users */ | |
158 | void sched_autogroup_detach(struct task_struct *p) | |
159 | { | |
160 | autogroup_move_group(p, &autogroup_default); | |
161 | } | |
162 | EXPORT_SYMBOL(sched_autogroup_detach); | |
163 | ||
164 | void sched_autogroup_fork(struct signal_struct *sig) | |
165 | { | |
4f821987 | 166 | sig->autogroup = autogroup_task_get(current); |
5091faa4 MG |
167 | } |
168 | ||
169 | void sched_autogroup_exit(struct signal_struct *sig) | |
170 | { | |
171 | autogroup_kref_put(sig->autogroup); | |
172 | } | |
173 | ||
174 | static int __init setup_autogroup(char *str) | |
175 | { | |
176 | sysctl_sched_autogroup_enabled = 0; | |
177 | ||
178 | return 1; | |
179 | } | |
180 | ||
181 | __setup("noautogroup", setup_autogroup); | |
182 | ||
183 | #ifdef CONFIG_PROC_FS | |
184 | ||
5091faa4 MG |
185 | int proc_sched_autogroup_set_nice(struct task_struct *p, int *nice) |
186 | { | |
187 | static unsigned long next = INITIAL_JIFFIES; | |
188 | struct autogroup *ag; | |
189 | int err; | |
190 | ||
191 | if (*nice < -20 || *nice > 19) | |
192 | return -EINVAL; | |
193 | ||
194 | err = security_task_setnice(current, *nice); | |
195 | if (err) | |
196 | return err; | |
197 | ||
198 | if (*nice < 0 && !can_nice(current, *nice)) | |
199 | return -EPERM; | |
200 | ||
201 | /* this is a heavy operation taking global locks.. */ | |
202 | if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next)) | |
203 | return -EAGAIN; | |
204 | ||
205 | next = HZ / 10 + jiffies; | |
4f821987 | 206 | ag = autogroup_task_get(p); |
5091faa4 MG |
207 | |
208 | down_write(&ag->lock); | |
209 | err = sched_group_set_shares(ag->tg, prio_to_weight[*nice + 20]); | |
210 | if (!err) | |
211 | ag->nice = *nice; | |
212 | up_write(&ag->lock); | |
213 | ||
214 | autogroup_kref_put(ag); | |
215 | ||
216 | return err; | |
217 | } | |
218 | ||
219 | void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m) | |
220 | { | |
4f821987 | 221 | struct autogroup *ag = autogroup_task_get(p); |
5091faa4 MG |
222 | |
223 | down_read(&ag->lock); | |
224 | seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice); | |
225 | up_read(&ag->lock); | |
226 | ||
227 | autogroup_kref_put(ag); | |
228 | } | |
229 | #endif /* CONFIG_PROC_FS */ | |
230 | ||
231 | #ifdef CONFIG_SCHED_DEBUG | |
232 | static inline int autogroup_path(struct task_group *tg, char *buf, int buflen) | |
233 | { | |
234 | return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id); | |
235 | } | |
236 | #endif /* CONFIG_SCHED_DEBUG */ | |
237 | ||
238 | #endif /* CONFIG_SCHED_AUTOGROUP */ |