Commit | Line | Data |
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31e4c28d VG |
1 | /* |
2 | * Common Block IO controller cgroup interface | |
3 | * | |
4 | * Based on ideas and code from CFQ, CFS and BFQ: | |
5 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> | |
6 | * | |
7 | * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> | |
8 | * Paolo Valente <paolo.valente@unimore.it> | |
9 | * | |
10 | * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> | |
11 | * Nauman Rafique <nauman@google.com> | |
12 | */ | |
13 | #include <linux/ioprio.h> | |
22084190 VG |
14 | #include <linux/seq_file.h> |
15 | #include <linux/kdev_t.h> | |
9d6a986c | 16 | #include <linux/module.h> |
accee785 | 17 | #include <linux/err.h> |
31e4c28d | 18 | #include "blk-cgroup.h" |
3e252066 VG |
19 | |
20 | static DEFINE_SPINLOCK(blkio_list_lock); | |
21 | static LIST_HEAD(blkio_list); | |
b1c35769 | 22 | |
31e4c28d | 23 | struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; |
9d6a986c VG |
24 | EXPORT_SYMBOL_GPL(blkio_root_cgroup); |
25 | ||
67523c48 BB |
26 | static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, |
27 | struct cgroup *); | |
28 | static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, | |
29 | struct task_struct *, bool); | |
30 | static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *, | |
31 | struct cgroup *, struct task_struct *, bool); | |
32 | static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); | |
33 | static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); | |
34 | ||
35 | struct cgroup_subsys blkio_subsys = { | |
36 | .name = "blkio", | |
37 | .create = blkiocg_create, | |
38 | .can_attach = blkiocg_can_attach, | |
39 | .attach = blkiocg_attach, | |
40 | .destroy = blkiocg_destroy, | |
41 | .populate = blkiocg_populate, | |
42 | #ifdef CONFIG_BLK_CGROUP | |
43 | /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ | |
44 | .subsys_id = blkio_subsys_id, | |
45 | #endif | |
46 | .use_id = 1, | |
47 | .module = THIS_MODULE, | |
48 | }; | |
49 | EXPORT_SYMBOL_GPL(blkio_subsys); | |
50 | ||
31e4c28d VG |
51 | struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) |
52 | { | |
53 | return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), | |
54 | struct blkio_cgroup, css); | |
55 | } | |
9d6a986c | 56 | EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); |
31e4c28d | 57 | |
22084190 VG |
58 | void blkiocg_update_blkio_group_stats(struct blkio_group *blkg, |
59 | unsigned long time, unsigned long sectors) | |
60 | { | |
61 | blkg->time += time; | |
62 | blkg->sectors += sectors; | |
63 | } | |
9d6a986c | 64 | EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_stats); |
22084190 | 65 | |
31e4c28d | 66 | void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, |
22084190 | 67 | struct blkio_group *blkg, void *key, dev_t dev) |
31e4c28d VG |
68 | { |
69 | unsigned long flags; | |
70 | ||
71 | spin_lock_irqsave(&blkcg->lock, flags); | |
72 | rcu_assign_pointer(blkg->key, key); | |
b1c35769 | 73 | blkg->blkcg_id = css_id(&blkcg->css); |
31e4c28d VG |
74 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); |
75 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
2868ef7b VG |
76 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
77 | /* Need to take css reference ? */ | |
78 | cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); | |
79 | #endif | |
22084190 | 80 | blkg->dev = dev; |
31e4c28d | 81 | } |
9d6a986c | 82 | EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group); |
31e4c28d | 83 | |
b1c35769 VG |
84 | static void __blkiocg_del_blkio_group(struct blkio_group *blkg) |
85 | { | |
86 | hlist_del_init_rcu(&blkg->blkcg_node); | |
87 | blkg->blkcg_id = 0; | |
88 | } | |
89 | ||
90 | /* | |
91 | * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 | |
92 | * indicating that blk_group was unhashed by the time we got to it. | |
93 | */ | |
31e4c28d VG |
94 | int blkiocg_del_blkio_group(struct blkio_group *blkg) |
95 | { | |
b1c35769 VG |
96 | struct blkio_cgroup *blkcg; |
97 | unsigned long flags; | |
98 | struct cgroup_subsys_state *css; | |
99 | int ret = 1; | |
100 | ||
101 | rcu_read_lock(); | |
102 | css = css_lookup(&blkio_subsys, blkg->blkcg_id); | |
103 | if (!css) | |
104 | goto out; | |
105 | ||
106 | blkcg = container_of(css, struct blkio_cgroup, css); | |
107 | spin_lock_irqsave(&blkcg->lock, flags); | |
108 | if (!hlist_unhashed(&blkg->blkcg_node)) { | |
109 | __blkiocg_del_blkio_group(blkg); | |
110 | ret = 0; | |
111 | } | |
112 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
113 | out: | |
114 | rcu_read_unlock(); | |
115 | return ret; | |
31e4c28d | 116 | } |
9d6a986c | 117 | EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); |
31e4c28d VG |
118 | |
119 | /* called under rcu_read_lock(). */ | |
120 | struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) | |
121 | { | |
122 | struct blkio_group *blkg; | |
123 | struct hlist_node *n; | |
124 | void *__key; | |
125 | ||
126 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
127 | __key = blkg->key; | |
128 | if (__key == key) | |
129 | return blkg; | |
130 | } | |
131 | ||
132 | return NULL; | |
133 | } | |
9d6a986c | 134 | EXPORT_SYMBOL_GPL(blkiocg_lookup_group); |
31e4c28d VG |
135 | |
136 | #define SHOW_FUNCTION(__VAR) \ | |
137 | static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ | |
138 | struct cftype *cftype) \ | |
139 | { \ | |
140 | struct blkio_cgroup *blkcg; \ | |
141 | \ | |
142 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
143 | return (u64)blkcg->__VAR; \ | |
144 | } | |
145 | ||
146 | SHOW_FUNCTION(weight); | |
147 | #undef SHOW_FUNCTION | |
148 | ||
149 | static int | |
150 | blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) | |
151 | { | |
152 | struct blkio_cgroup *blkcg; | |
f8d461d6 VG |
153 | struct blkio_group *blkg; |
154 | struct hlist_node *n; | |
3e252066 | 155 | struct blkio_policy_type *blkiop; |
31e4c28d VG |
156 | |
157 | if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) | |
158 | return -EINVAL; | |
159 | ||
160 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
bcf4dd43 | 161 | spin_lock(&blkio_list_lock); |
f8d461d6 | 162 | spin_lock_irq(&blkcg->lock); |
31e4c28d | 163 | blkcg->weight = (unsigned int)val; |
3e252066 | 164 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
3e252066 VG |
165 | list_for_each_entry(blkiop, &blkio_list, list) |
166 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
167 | blkcg->weight); | |
3e252066 | 168 | } |
f8d461d6 | 169 | spin_unlock_irq(&blkcg->lock); |
bcf4dd43 | 170 | spin_unlock(&blkio_list_lock); |
31e4c28d VG |
171 | return 0; |
172 | } | |
173 | ||
22084190 VG |
174 | #define SHOW_FUNCTION_PER_GROUP(__VAR) \ |
175 | static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ | |
176 | struct cftype *cftype, struct seq_file *m) \ | |
177 | { \ | |
178 | struct blkio_cgroup *blkcg; \ | |
179 | struct blkio_group *blkg; \ | |
180 | struct hlist_node *n; \ | |
181 | \ | |
182 | if (!cgroup_lock_live_group(cgroup)) \ | |
183 | return -ENODEV; \ | |
184 | \ | |
185 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
186 | rcu_read_lock(); \ | |
187 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ | |
188 | if (blkg->dev) \ | |
189 | seq_printf(m, "%u:%u %lu\n", MAJOR(blkg->dev), \ | |
190 | MINOR(blkg->dev), blkg->__VAR); \ | |
191 | } \ | |
192 | rcu_read_unlock(); \ | |
193 | cgroup_unlock(); \ | |
194 | return 0; \ | |
195 | } | |
196 | ||
197 | SHOW_FUNCTION_PER_GROUP(time); | |
198 | SHOW_FUNCTION_PER_GROUP(sectors); | |
199 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
200 | SHOW_FUNCTION_PER_GROUP(dequeue); | |
201 | #endif | |
202 | #undef SHOW_FUNCTION_PER_GROUP | |
203 | ||
204 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
205 | void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg, | |
206 | unsigned long dequeue) | |
207 | { | |
208 | blkg->dequeue += dequeue; | |
209 | } | |
9d6a986c | 210 | EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_dequeue_stats); |
22084190 VG |
211 | #endif |
212 | ||
31e4c28d VG |
213 | struct cftype blkio_files[] = { |
214 | { | |
215 | .name = "weight", | |
216 | .read_u64 = blkiocg_weight_read, | |
217 | .write_u64 = blkiocg_weight_write, | |
218 | }, | |
22084190 VG |
219 | { |
220 | .name = "time", | |
221 | .read_seq_string = blkiocg_time_read, | |
222 | }, | |
223 | { | |
224 | .name = "sectors", | |
225 | .read_seq_string = blkiocg_sectors_read, | |
226 | }, | |
227 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
228 | { | |
229 | .name = "dequeue", | |
230 | .read_seq_string = blkiocg_dequeue_read, | |
231 | }, | |
232 | #endif | |
31e4c28d VG |
233 | }; |
234 | ||
235 | static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
236 | { | |
237 | return cgroup_add_files(cgroup, subsys, blkio_files, | |
238 | ARRAY_SIZE(blkio_files)); | |
239 | } | |
240 | ||
241 | static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
242 | { | |
243 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
b1c35769 VG |
244 | unsigned long flags; |
245 | struct blkio_group *blkg; | |
246 | void *key; | |
3e252066 | 247 | struct blkio_policy_type *blkiop; |
b1c35769 VG |
248 | |
249 | rcu_read_lock(); | |
250 | remove_entry: | |
251 | spin_lock_irqsave(&blkcg->lock, flags); | |
252 | ||
253 | if (hlist_empty(&blkcg->blkg_list)) { | |
254 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
255 | goto done; | |
256 | } | |
257 | ||
258 | blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, | |
259 | blkcg_node); | |
260 | key = rcu_dereference(blkg->key); | |
261 | __blkiocg_del_blkio_group(blkg); | |
31e4c28d | 262 | |
b1c35769 VG |
263 | spin_unlock_irqrestore(&blkcg->lock, flags); |
264 | ||
265 | /* | |
266 | * This blkio_group is being unlinked as associated cgroup is going | |
267 | * away. Let all the IO controlling policies know about this event. | |
268 | * | |
269 | * Currently this is static call to one io controlling policy. Once | |
270 | * we have more policies in place, we need some dynamic registration | |
271 | * of callback function. | |
272 | */ | |
3e252066 VG |
273 | spin_lock(&blkio_list_lock); |
274 | list_for_each_entry(blkiop, &blkio_list, list) | |
275 | blkiop->ops.blkio_unlink_group_fn(key, blkg); | |
276 | spin_unlock(&blkio_list_lock); | |
b1c35769 VG |
277 | goto remove_entry; |
278 | done: | |
31e4c28d | 279 | free_css_id(&blkio_subsys, &blkcg->css); |
b1c35769 | 280 | rcu_read_unlock(); |
67523c48 BB |
281 | if (blkcg != &blkio_root_cgroup) |
282 | kfree(blkcg); | |
31e4c28d VG |
283 | } |
284 | ||
285 | static struct cgroup_subsys_state * | |
286 | blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
287 | { | |
288 | struct blkio_cgroup *blkcg, *parent_blkcg; | |
289 | ||
290 | if (!cgroup->parent) { | |
291 | blkcg = &blkio_root_cgroup; | |
292 | goto done; | |
293 | } | |
294 | ||
295 | /* Currently we do not support hierarchy deeper than two level (0,1) */ | |
296 | parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); | |
297 | if (css_depth(&parent_blkcg->css) > 0) | |
298 | return ERR_PTR(-EINVAL); | |
299 | ||
300 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
301 | if (!blkcg) | |
302 | return ERR_PTR(-ENOMEM); | |
303 | ||
304 | blkcg->weight = BLKIO_WEIGHT_DEFAULT; | |
305 | done: | |
306 | spin_lock_init(&blkcg->lock); | |
307 | INIT_HLIST_HEAD(&blkcg->blkg_list); | |
308 | ||
309 | return &blkcg->css; | |
310 | } | |
311 | ||
312 | /* | |
313 | * We cannot support shared io contexts, as we have no mean to support | |
314 | * two tasks with the same ioc in two different groups without major rework | |
315 | * of the main cic data structures. For now we allow a task to change | |
316 | * its cgroup only if it's the only owner of its ioc. | |
317 | */ | |
318 | static int blkiocg_can_attach(struct cgroup_subsys *subsys, | |
319 | struct cgroup *cgroup, struct task_struct *tsk, | |
320 | bool threadgroup) | |
321 | { | |
322 | struct io_context *ioc; | |
323 | int ret = 0; | |
324 | ||
325 | /* task_lock() is needed to avoid races with exit_io_context() */ | |
326 | task_lock(tsk); | |
327 | ioc = tsk->io_context; | |
328 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) | |
329 | ret = -EINVAL; | |
330 | task_unlock(tsk); | |
331 | ||
332 | return ret; | |
333 | } | |
334 | ||
335 | static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, | |
336 | struct cgroup *prev, struct task_struct *tsk, | |
337 | bool threadgroup) | |
338 | { | |
339 | struct io_context *ioc; | |
340 | ||
341 | task_lock(tsk); | |
342 | ioc = tsk->io_context; | |
343 | if (ioc) | |
344 | ioc->cgroup_changed = 1; | |
345 | task_unlock(tsk); | |
346 | } | |
347 | ||
3e252066 VG |
348 | void blkio_policy_register(struct blkio_policy_type *blkiop) |
349 | { | |
350 | spin_lock(&blkio_list_lock); | |
351 | list_add_tail(&blkiop->list, &blkio_list); | |
352 | spin_unlock(&blkio_list_lock); | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(blkio_policy_register); | |
355 | ||
356 | void blkio_policy_unregister(struct blkio_policy_type *blkiop) | |
357 | { | |
358 | spin_lock(&blkio_list_lock); | |
359 | list_del_init(&blkiop->list); | |
360 | spin_unlock(&blkio_list_lock); | |
361 | } | |
362 | EXPORT_SYMBOL_GPL(blkio_policy_unregister); | |
67523c48 BB |
363 | |
364 | static int __init init_cgroup_blkio(void) | |
365 | { | |
366 | return cgroup_load_subsys(&blkio_subsys); | |
367 | } | |
368 | ||
369 | static void __exit exit_cgroup_blkio(void) | |
370 | { | |
371 | cgroup_unload_subsys(&blkio_subsys); | |
372 | } | |
373 | ||
374 | module_init(init_cgroup_blkio); | |
375 | module_exit(exit_cgroup_blkio); | |
376 | MODULE_LICENSE("GPL"); |