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