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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> |
9195291e | 18 | #include <linux/blkdev.h> |
31e4c28d | 19 | #include "blk-cgroup.h" |
34d0f179 | 20 | #include <linux/genhd.h> |
3e252066 | 21 | |
84c124da DS |
22 | #define MAX_KEY_LEN 100 |
23 | ||
3e252066 VG |
24 | static DEFINE_SPINLOCK(blkio_list_lock); |
25 | static LIST_HEAD(blkio_list); | |
b1c35769 | 26 | |
31e4c28d | 27 | struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; |
9d6a986c VG |
28 | EXPORT_SYMBOL_GPL(blkio_root_cgroup); |
29 | ||
67523c48 BB |
30 | static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, |
31 | struct cgroup *); | |
32 | static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, | |
33 | struct task_struct *, bool); | |
34 | static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *, | |
35 | struct cgroup *, struct task_struct *, bool); | |
36 | static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); | |
37 | static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); | |
38 | ||
39 | struct cgroup_subsys blkio_subsys = { | |
40 | .name = "blkio", | |
41 | .create = blkiocg_create, | |
42 | .can_attach = blkiocg_can_attach, | |
43 | .attach = blkiocg_attach, | |
44 | .destroy = blkiocg_destroy, | |
45 | .populate = blkiocg_populate, | |
46 | #ifdef CONFIG_BLK_CGROUP | |
47 | /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ | |
48 | .subsys_id = blkio_subsys_id, | |
49 | #endif | |
50 | .use_id = 1, | |
51 | .module = THIS_MODULE, | |
52 | }; | |
53 | EXPORT_SYMBOL_GPL(blkio_subsys); | |
54 | ||
34d0f179 GJ |
55 | static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg, |
56 | struct blkio_policy_node *pn) | |
57 | { | |
58 | list_add(&pn->node, &blkcg->policy_list); | |
59 | } | |
60 | ||
61 | /* Must be called with blkcg->lock held */ | |
62 | static inline void blkio_policy_delete_node(struct blkio_policy_node *pn) | |
63 | { | |
64 | list_del(&pn->node); | |
65 | } | |
66 | ||
67 | /* Must be called with blkcg->lock held */ | |
68 | static struct blkio_policy_node * | |
69 | blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev) | |
70 | { | |
71 | struct blkio_policy_node *pn; | |
72 | ||
73 | list_for_each_entry(pn, &blkcg->policy_list, node) { | |
74 | if (pn->dev == dev) | |
75 | return pn; | |
76 | } | |
77 | ||
78 | return NULL; | |
79 | } | |
80 | ||
31e4c28d VG |
81 | struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) |
82 | { | |
83 | return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), | |
84 | struct blkio_cgroup, css); | |
85 | } | |
9d6a986c | 86 | EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); |
31e4c28d | 87 | |
84c124da DS |
88 | void blkio_group_init(struct blkio_group *blkg) |
89 | { | |
90 | spin_lock_init(&blkg->stats_lock); | |
91 | } | |
92 | EXPORT_SYMBOL_GPL(blkio_group_init); | |
93 | ||
9195291e DS |
94 | /* |
95 | * Add to the appropriate stat variable depending on the request type. | |
96 | * This should be called with the blkg->stats_lock held. | |
97 | */ | |
84c124da DS |
98 | static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction, |
99 | bool sync) | |
9195291e | 100 | { |
84c124da DS |
101 | if (direction) |
102 | stat[BLKIO_STAT_WRITE] += add; | |
9195291e | 103 | else |
84c124da DS |
104 | stat[BLKIO_STAT_READ] += add; |
105 | if (sync) | |
106 | stat[BLKIO_STAT_SYNC] += add; | |
9195291e | 107 | else |
84c124da | 108 | stat[BLKIO_STAT_ASYNC] += add; |
9195291e DS |
109 | } |
110 | ||
cdc1184c DS |
111 | /* |
112 | * Decrements the appropriate stat variable if non-zero depending on the | |
113 | * request type. Panics on value being zero. | |
114 | * This should be called with the blkg->stats_lock held. | |
115 | */ | |
116 | static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync) | |
117 | { | |
118 | if (direction) { | |
119 | BUG_ON(stat[BLKIO_STAT_WRITE] == 0); | |
120 | stat[BLKIO_STAT_WRITE]--; | |
121 | } else { | |
122 | BUG_ON(stat[BLKIO_STAT_READ] == 0); | |
123 | stat[BLKIO_STAT_READ]--; | |
124 | } | |
125 | if (sync) { | |
126 | BUG_ON(stat[BLKIO_STAT_SYNC] == 0); | |
127 | stat[BLKIO_STAT_SYNC]--; | |
128 | } else { | |
129 | BUG_ON(stat[BLKIO_STAT_ASYNC] == 0); | |
130 | stat[BLKIO_STAT_ASYNC]--; | |
131 | } | |
132 | } | |
133 | ||
134 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
812df48d DS |
135 | /* This should be called with the blkg->stats_lock held. */ |
136 | static void blkio_set_start_group_wait_time(struct blkio_group *blkg, | |
137 | struct blkio_group *curr_blkg) | |
138 | { | |
139 | if (blkio_blkg_waiting(&blkg->stats)) | |
140 | return; | |
141 | if (blkg == curr_blkg) | |
142 | return; | |
143 | blkg->stats.start_group_wait_time = sched_clock(); | |
144 | blkio_mark_blkg_waiting(&blkg->stats); | |
145 | } | |
146 | ||
147 | /* This should be called with the blkg->stats_lock held. */ | |
148 | static void blkio_update_group_wait_time(struct blkio_group_stats *stats) | |
149 | { | |
150 | unsigned long long now; | |
151 | ||
152 | if (!blkio_blkg_waiting(stats)) | |
153 | return; | |
154 | ||
155 | now = sched_clock(); | |
156 | if (time_after64(now, stats->start_group_wait_time)) | |
157 | stats->group_wait_time += now - stats->start_group_wait_time; | |
158 | blkio_clear_blkg_waiting(stats); | |
159 | } | |
160 | ||
161 | /* This should be called with the blkg->stats_lock held. */ | |
162 | static void blkio_end_empty_time(struct blkio_group_stats *stats) | |
163 | { | |
164 | unsigned long long now; | |
165 | ||
166 | if (!blkio_blkg_empty(stats)) | |
167 | return; | |
168 | ||
169 | now = sched_clock(); | |
170 | if (time_after64(now, stats->start_empty_time)) | |
171 | stats->empty_time += now - stats->start_empty_time; | |
172 | blkio_clear_blkg_empty(stats); | |
173 | } | |
174 | ||
175 | void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) | |
176 | { | |
177 | unsigned long flags; | |
178 | ||
179 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
180 | BUG_ON(blkio_blkg_idling(&blkg->stats)); | |
181 | blkg->stats.start_idle_time = sched_clock(); | |
182 | blkio_mark_blkg_idling(&blkg->stats); | |
183 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
184 | } | |
185 | EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats); | |
186 | ||
187 | void blkiocg_update_idle_time_stats(struct blkio_group *blkg) | |
188 | { | |
189 | unsigned long flags; | |
190 | unsigned long long now; | |
191 | struct blkio_group_stats *stats; | |
192 | ||
193 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
194 | stats = &blkg->stats; | |
195 | if (blkio_blkg_idling(stats)) { | |
196 | now = sched_clock(); | |
197 | if (time_after64(now, stats->start_idle_time)) | |
198 | stats->idle_time += now - stats->start_idle_time; | |
199 | blkio_clear_blkg_idling(stats); | |
200 | } | |
201 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
202 | } | |
203 | EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats); | |
204 | ||
cdc1184c DS |
205 | void blkiocg_update_set_active_queue_stats(struct blkio_group *blkg) |
206 | { | |
207 | unsigned long flags; | |
208 | struct blkio_group_stats *stats; | |
209 | ||
210 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
211 | stats = &blkg->stats; | |
212 | stats->avg_queue_size_sum += | |
213 | stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] + | |
214 | stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]; | |
215 | stats->avg_queue_size_samples++; | |
812df48d | 216 | blkio_update_group_wait_time(stats); |
cdc1184c DS |
217 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
218 | } | |
219 | EXPORT_SYMBOL_GPL(blkiocg_update_set_active_queue_stats); | |
812df48d DS |
220 | #else |
221 | static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg, | |
222 | struct blkio_group *curr_blkg) {} | |
223 | static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {} | |
cdc1184c DS |
224 | #endif |
225 | ||
226 | void blkiocg_update_request_add_stats(struct blkio_group *blkg, | |
227 | struct blkio_group *curr_blkg, bool direction, | |
228 | bool sync) | |
229 | { | |
230 | unsigned long flags; | |
231 | ||
232 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
233 | blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction, | |
234 | sync); | |
812df48d DS |
235 | blkio_end_empty_time(&blkg->stats); |
236 | blkio_set_start_group_wait_time(blkg, curr_blkg); | |
cdc1184c DS |
237 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
238 | } | |
239 | EXPORT_SYMBOL_GPL(blkiocg_update_request_add_stats); | |
240 | ||
241 | void blkiocg_update_request_remove_stats(struct blkio_group *blkg, | |
242 | bool direction, bool sync) | |
243 | { | |
244 | unsigned long flags; | |
245 | ||
246 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
247 | blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], | |
248 | direction, sync); | |
249 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
250 | } | |
251 | EXPORT_SYMBOL_GPL(blkiocg_update_request_remove_stats); | |
252 | ||
303a3acb | 253 | void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time) |
22084190 | 254 | { |
303a3acb DS |
255 | unsigned long flags; |
256 | ||
257 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
258 | blkg->stats.time += time; | |
259 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
22084190 | 260 | } |
303a3acb | 261 | EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); |
22084190 | 262 | |
812df48d DS |
263 | void blkiocg_set_start_empty_time(struct blkio_group *blkg, bool ignore) |
264 | { | |
265 | unsigned long flags; | |
266 | struct blkio_group_stats *stats; | |
267 | ||
268 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
269 | stats = &blkg->stats; | |
270 | ||
271 | if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] || | |
272 | stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) { | |
273 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
274 | return; | |
275 | } | |
276 | ||
277 | /* | |
278 | * If ignore is set, we do not panic on the empty flag being set | |
279 | * already. This is to avoid cases where there are superfluous timeslice | |
280 | * complete events (for eg., forced_dispatch in CFQ) when no IOs are | |
281 | * served which could result in triggering the empty check incorrectly. | |
282 | */ | |
283 | BUG_ON(!ignore && blkio_blkg_empty(stats)); | |
284 | stats->start_empty_time = sched_clock(); | |
285 | blkio_mark_blkg_empty(stats); | |
286 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
287 | } | |
288 | EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time); | |
289 | ||
84c124da DS |
290 | void blkiocg_update_dispatch_stats(struct blkio_group *blkg, |
291 | uint64_t bytes, bool direction, bool sync) | |
9195291e DS |
292 | { |
293 | struct blkio_group_stats *stats; | |
294 | unsigned long flags; | |
295 | ||
296 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
297 | stats = &blkg->stats; | |
84c124da DS |
298 | stats->sectors += bytes >> 9; |
299 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction, | |
300 | sync); | |
301 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes, | |
302 | direction, sync); | |
9195291e DS |
303 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
304 | } | |
84c124da | 305 | EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats); |
9195291e | 306 | |
84c124da DS |
307 | void blkiocg_update_completion_stats(struct blkio_group *blkg, |
308 | uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) | |
9195291e DS |
309 | { |
310 | struct blkio_group_stats *stats; | |
311 | unsigned long flags; | |
312 | unsigned long long now = sched_clock(); | |
313 | ||
314 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
315 | stats = &blkg->stats; | |
84c124da DS |
316 | if (time_after64(now, io_start_time)) |
317 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME], | |
318 | now - io_start_time, direction, sync); | |
319 | if (time_after64(io_start_time, start_time)) | |
320 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME], | |
321 | io_start_time - start_time, direction, sync); | |
9195291e DS |
322 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
323 | } | |
84c124da | 324 | EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); |
9195291e | 325 | |
812d4026 DS |
326 | void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, |
327 | bool sync) | |
328 | { | |
329 | unsigned long flags; | |
330 | ||
331 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
332 | blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction, | |
333 | sync); | |
334 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
335 | } | |
336 | EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); | |
337 | ||
31e4c28d | 338 | void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, |
22084190 | 339 | struct blkio_group *blkg, void *key, dev_t dev) |
31e4c28d VG |
340 | { |
341 | unsigned long flags; | |
342 | ||
343 | spin_lock_irqsave(&blkcg->lock, flags); | |
344 | rcu_assign_pointer(blkg->key, key); | |
b1c35769 | 345 | blkg->blkcg_id = css_id(&blkcg->css); |
31e4c28d VG |
346 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); |
347 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
2868ef7b VG |
348 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
349 | /* Need to take css reference ? */ | |
350 | cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); | |
351 | #endif | |
22084190 | 352 | blkg->dev = dev; |
31e4c28d | 353 | } |
9d6a986c | 354 | EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group); |
31e4c28d | 355 | |
b1c35769 VG |
356 | static void __blkiocg_del_blkio_group(struct blkio_group *blkg) |
357 | { | |
358 | hlist_del_init_rcu(&blkg->blkcg_node); | |
359 | blkg->blkcg_id = 0; | |
360 | } | |
361 | ||
362 | /* | |
363 | * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 | |
364 | * indicating that blk_group was unhashed by the time we got to it. | |
365 | */ | |
31e4c28d VG |
366 | int blkiocg_del_blkio_group(struct blkio_group *blkg) |
367 | { | |
b1c35769 VG |
368 | struct blkio_cgroup *blkcg; |
369 | unsigned long flags; | |
370 | struct cgroup_subsys_state *css; | |
371 | int ret = 1; | |
372 | ||
373 | rcu_read_lock(); | |
374 | css = css_lookup(&blkio_subsys, blkg->blkcg_id); | |
375 | if (!css) | |
376 | goto out; | |
377 | ||
378 | blkcg = container_of(css, struct blkio_cgroup, css); | |
379 | spin_lock_irqsave(&blkcg->lock, flags); | |
380 | if (!hlist_unhashed(&blkg->blkcg_node)) { | |
381 | __blkiocg_del_blkio_group(blkg); | |
382 | ret = 0; | |
383 | } | |
384 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
385 | out: | |
386 | rcu_read_unlock(); | |
387 | return ret; | |
31e4c28d | 388 | } |
9d6a986c | 389 | EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); |
31e4c28d VG |
390 | |
391 | /* called under rcu_read_lock(). */ | |
392 | struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) | |
393 | { | |
394 | struct blkio_group *blkg; | |
395 | struct hlist_node *n; | |
396 | void *__key; | |
397 | ||
398 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
399 | __key = blkg->key; | |
400 | if (__key == key) | |
401 | return blkg; | |
402 | } | |
403 | ||
404 | return NULL; | |
405 | } | |
9d6a986c | 406 | EXPORT_SYMBOL_GPL(blkiocg_lookup_group); |
31e4c28d VG |
407 | |
408 | #define SHOW_FUNCTION(__VAR) \ | |
409 | static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ | |
410 | struct cftype *cftype) \ | |
411 | { \ | |
412 | struct blkio_cgroup *blkcg; \ | |
413 | \ | |
414 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
415 | return (u64)blkcg->__VAR; \ | |
416 | } | |
417 | ||
418 | SHOW_FUNCTION(weight); | |
419 | #undef SHOW_FUNCTION | |
420 | ||
421 | static int | |
422 | blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) | |
423 | { | |
424 | struct blkio_cgroup *blkcg; | |
f8d461d6 VG |
425 | struct blkio_group *blkg; |
426 | struct hlist_node *n; | |
3e252066 | 427 | struct blkio_policy_type *blkiop; |
34d0f179 | 428 | struct blkio_policy_node *pn; |
31e4c28d VG |
429 | |
430 | if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) | |
431 | return -EINVAL; | |
432 | ||
433 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
bcf4dd43 | 434 | spin_lock(&blkio_list_lock); |
f8d461d6 | 435 | spin_lock_irq(&blkcg->lock); |
31e4c28d | 436 | blkcg->weight = (unsigned int)val; |
34d0f179 | 437 | |
3e252066 | 438 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
34d0f179 GJ |
439 | pn = blkio_policy_search_node(blkcg, blkg->dev); |
440 | ||
441 | if (pn) | |
442 | continue; | |
443 | ||
3e252066 VG |
444 | list_for_each_entry(blkiop, &blkio_list, list) |
445 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
446 | blkcg->weight); | |
3e252066 | 447 | } |
f8d461d6 | 448 | spin_unlock_irq(&blkcg->lock); |
bcf4dd43 | 449 | spin_unlock(&blkio_list_lock); |
31e4c28d VG |
450 | return 0; |
451 | } | |
452 | ||
303a3acb | 453 | static int |
84c124da | 454 | blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) |
303a3acb DS |
455 | { |
456 | struct blkio_cgroup *blkcg; | |
457 | struct blkio_group *blkg; | |
812df48d | 458 | struct blkio_group_stats *stats; |
303a3acb | 459 | struct hlist_node *n; |
cdc1184c DS |
460 | uint64_t queued[BLKIO_STAT_TOTAL]; |
461 | int i; | |
812df48d DS |
462 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
463 | bool idling, waiting, empty; | |
464 | unsigned long long now = sched_clock(); | |
465 | #endif | |
303a3acb DS |
466 | |
467 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
468 | spin_lock_irq(&blkcg->lock); | |
469 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
470 | spin_lock(&blkg->stats_lock); | |
812df48d DS |
471 | stats = &blkg->stats; |
472 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
473 | idling = blkio_blkg_idling(stats); | |
474 | waiting = blkio_blkg_waiting(stats); | |
475 | empty = blkio_blkg_empty(stats); | |
476 | #endif | |
cdc1184c | 477 | for (i = 0; i < BLKIO_STAT_TOTAL; i++) |
812df48d DS |
478 | queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i]; |
479 | memset(stats, 0, sizeof(struct blkio_group_stats)); | |
cdc1184c | 480 | for (i = 0; i < BLKIO_STAT_TOTAL; i++) |
812df48d DS |
481 | stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i]; |
482 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
483 | if (idling) { | |
484 | blkio_mark_blkg_idling(stats); | |
485 | stats->start_idle_time = now; | |
486 | } | |
487 | if (waiting) { | |
488 | blkio_mark_blkg_waiting(stats); | |
489 | stats->start_group_wait_time = now; | |
490 | } | |
491 | if (empty) { | |
492 | blkio_mark_blkg_empty(stats); | |
493 | stats->start_empty_time = now; | |
494 | } | |
495 | #endif | |
303a3acb DS |
496 | spin_unlock(&blkg->stats_lock); |
497 | } | |
498 | spin_unlock_irq(&blkcg->lock); | |
499 | return 0; | |
500 | } | |
501 | ||
84c124da DS |
502 | static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, |
503 | int chars_left, bool diskname_only) | |
303a3acb | 504 | { |
84c124da | 505 | snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); |
303a3acb DS |
506 | chars_left -= strlen(str); |
507 | if (chars_left <= 0) { | |
508 | printk(KERN_WARNING | |
509 | "Possibly incorrect cgroup stat display format"); | |
510 | return; | |
511 | } | |
84c124da DS |
512 | if (diskname_only) |
513 | return; | |
303a3acb | 514 | switch (type) { |
84c124da | 515 | case BLKIO_STAT_READ: |
303a3acb DS |
516 | strlcat(str, " Read", chars_left); |
517 | break; | |
84c124da | 518 | case BLKIO_STAT_WRITE: |
303a3acb DS |
519 | strlcat(str, " Write", chars_left); |
520 | break; | |
84c124da | 521 | case BLKIO_STAT_SYNC: |
303a3acb DS |
522 | strlcat(str, " Sync", chars_left); |
523 | break; | |
84c124da | 524 | case BLKIO_STAT_ASYNC: |
303a3acb DS |
525 | strlcat(str, " Async", chars_left); |
526 | break; | |
84c124da | 527 | case BLKIO_STAT_TOTAL: |
303a3acb DS |
528 | strlcat(str, " Total", chars_left); |
529 | break; | |
530 | default: | |
531 | strlcat(str, " Invalid", chars_left); | |
532 | } | |
533 | } | |
534 | ||
84c124da DS |
535 | static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, |
536 | struct cgroup_map_cb *cb, dev_t dev) | |
537 | { | |
538 | blkio_get_key_name(0, dev, str, chars_left, true); | |
539 | cb->fill(cb, str, val); | |
540 | return val; | |
541 | } | |
303a3acb | 542 | |
84c124da DS |
543 | /* This should be called with blkg->stats_lock held */ |
544 | static uint64_t blkio_get_stat(struct blkio_group *blkg, | |
545 | struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) | |
303a3acb DS |
546 | { |
547 | uint64_t disk_total; | |
548 | char key_str[MAX_KEY_LEN]; | |
84c124da DS |
549 | enum stat_sub_type sub_type; |
550 | ||
551 | if (type == BLKIO_STAT_TIME) | |
552 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
553 | blkg->stats.time, cb, dev); | |
554 | if (type == BLKIO_STAT_SECTORS) | |
555 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
556 | blkg->stats.sectors, cb, dev); | |
557 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
cdc1184c DS |
558 | if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { |
559 | uint64_t sum = blkg->stats.avg_queue_size_sum; | |
560 | uint64_t samples = blkg->stats.avg_queue_size_samples; | |
561 | if (samples) | |
562 | do_div(sum, samples); | |
563 | else | |
564 | sum = 0; | |
565 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev); | |
566 | } | |
812df48d DS |
567 | if (type == BLKIO_STAT_GROUP_WAIT_TIME) |
568 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
569 | blkg->stats.group_wait_time, cb, dev); | |
570 | if (type == BLKIO_STAT_IDLE_TIME) | |
571 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
572 | blkg->stats.idle_time, cb, dev); | |
573 | if (type == BLKIO_STAT_EMPTY_TIME) | |
574 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
575 | blkg->stats.empty_time, cb, dev); | |
84c124da DS |
576 | if (type == BLKIO_STAT_DEQUEUE) |
577 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
578 | blkg->stats.dequeue, cb, dev); | |
579 | #endif | |
303a3acb | 580 | |
84c124da DS |
581 | for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; |
582 | sub_type++) { | |
583 | blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); | |
584 | cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); | |
303a3acb | 585 | } |
84c124da DS |
586 | disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + |
587 | blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; | |
588 | blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); | |
303a3acb DS |
589 | cb->fill(cb, key_str, disk_total); |
590 | return disk_total; | |
591 | } | |
592 | ||
84c124da | 593 | #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \ |
22084190 | 594 | static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ |
303a3acb | 595 | struct cftype *cftype, struct cgroup_map_cb *cb) \ |
22084190 VG |
596 | { \ |
597 | struct blkio_cgroup *blkcg; \ | |
598 | struct blkio_group *blkg; \ | |
599 | struct hlist_node *n; \ | |
303a3acb | 600 | uint64_t cgroup_total = 0; \ |
22084190 VG |
601 | \ |
602 | if (!cgroup_lock_live_group(cgroup)) \ | |
603 | return -ENODEV; \ | |
604 | \ | |
605 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
606 | rcu_read_lock(); \ | |
607 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ | |
303a3acb DS |
608 | if (blkg->dev) { \ |
609 | spin_lock_irq(&blkg->stats_lock); \ | |
84c124da DS |
610 | cgroup_total += blkio_get_stat(blkg, cb, \ |
611 | blkg->dev, type); \ | |
303a3acb DS |
612 | spin_unlock_irq(&blkg->stats_lock); \ |
613 | } \ | |
22084190 | 614 | } \ |
303a3acb DS |
615 | if (show_total) \ |
616 | cb->fill(cb, "Total", cgroup_total); \ | |
22084190 VG |
617 | rcu_read_unlock(); \ |
618 | cgroup_unlock(); \ | |
619 | return 0; \ | |
620 | } | |
621 | ||
84c124da DS |
622 | SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0); |
623 | SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0); | |
624 | SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1); | |
625 | SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1); | |
626 | SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1); | |
627 | SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1); | |
812d4026 | 628 | SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1); |
cdc1184c | 629 | SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1); |
22084190 | 630 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
84c124da | 631 | SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0); |
cdc1184c | 632 | SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0); |
812df48d DS |
633 | SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0); |
634 | SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0); | |
635 | SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0); | |
22084190 VG |
636 | #endif |
637 | #undef SHOW_FUNCTION_PER_GROUP | |
638 | ||
639 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
9195291e | 640 | void blkiocg_update_dequeue_stats(struct blkio_group *blkg, |
22084190 VG |
641 | unsigned long dequeue) |
642 | { | |
303a3acb | 643 | blkg->stats.dequeue += dequeue; |
22084190 | 644 | } |
9195291e | 645 | EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); |
22084190 VG |
646 | #endif |
647 | ||
34d0f179 GJ |
648 | static int blkio_check_dev_num(dev_t dev) |
649 | { | |
650 | int part = 0; | |
651 | struct gendisk *disk; | |
652 | ||
653 | disk = get_gendisk(dev, &part); | |
654 | if (!disk || part) | |
655 | return -ENODEV; | |
656 | ||
657 | return 0; | |
658 | } | |
659 | ||
660 | static int blkio_policy_parse_and_set(char *buf, | |
661 | struct blkio_policy_node *newpn) | |
662 | { | |
663 | char *s[4], *p, *major_s = NULL, *minor_s = NULL; | |
664 | int ret; | |
665 | unsigned long major, minor, temp; | |
666 | int i = 0; | |
667 | dev_t dev; | |
668 | ||
669 | memset(s, 0, sizeof(s)); | |
670 | ||
671 | while ((p = strsep(&buf, " ")) != NULL) { | |
672 | if (!*p) | |
673 | continue; | |
674 | ||
675 | s[i++] = p; | |
676 | ||
677 | /* Prevent from inputing too many things */ | |
678 | if (i == 3) | |
679 | break; | |
680 | } | |
681 | ||
682 | if (i != 2) | |
683 | return -EINVAL; | |
684 | ||
685 | p = strsep(&s[0], ":"); | |
686 | if (p != NULL) | |
687 | major_s = p; | |
688 | else | |
689 | return -EINVAL; | |
690 | ||
691 | minor_s = s[0]; | |
692 | if (!minor_s) | |
693 | return -EINVAL; | |
694 | ||
695 | ret = strict_strtoul(major_s, 10, &major); | |
696 | if (ret) | |
697 | return -EINVAL; | |
698 | ||
699 | ret = strict_strtoul(minor_s, 10, &minor); | |
700 | if (ret) | |
701 | return -EINVAL; | |
702 | ||
703 | dev = MKDEV(major, minor); | |
704 | ||
705 | ret = blkio_check_dev_num(dev); | |
706 | if (ret) | |
707 | return ret; | |
708 | ||
709 | newpn->dev = dev; | |
710 | ||
711 | if (s[1] == NULL) | |
712 | return -EINVAL; | |
713 | ||
714 | ret = strict_strtoul(s[1], 10, &temp); | |
715 | if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) || | |
716 | temp > BLKIO_WEIGHT_MAX) | |
717 | return -EINVAL; | |
718 | ||
719 | newpn->weight = temp; | |
720 | ||
721 | return 0; | |
722 | } | |
723 | ||
724 | unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg, | |
725 | dev_t dev) | |
726 | { | |
727 | struct blkio_policy_node *pn; | |
728 | ||
729 | pn = blkio_policy_search_node(blkcg, dev); | |
730 | if (pn) | |
731 | return pn->weight; | |
732 | else | |
733 | return blkcg->weight; | |
734 | } | |
735 | EXPORT_SYMBOL_GPL(blkcg_get_weight); | |
736 | ||
737 | ||
738 | static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft, | |
739 | const char *buffer) | |
740 | { | |
741 | int ret = 0; | |
742 | char *buf; | |
743 | struct blkio_policy_node *newpn, *pn; | |
744 | struct blkio_cgroup *blkcg; | |
745 | struct blkio_group *blkg; | |
746 | int keep_newpn = 0; | |
747 | struct hlist_node *n; | |
748 | struct blkio_policy_type *blkiop; | |
749 | ||
750 | buf = kstrdup(buffer, GFP_KERNEL); | |
751 | if (!buf) | |
752 | return -ENOMEM; | |
753 | ||
754 | newpn = kzalloc(sizeof(*newpn), GFP_KERNEL); | |
755 | if (!newpn) { | |
756 | ret = -ENOMEM; | |
757 | goto free_buf; | |
758 | } | |
759 | ||
760 | ret = blkio_policy_parse_and_set(buf, newpn); | |
761 | if (ret) | |
762 | goto free_newpn; | |
763 | ||
764 | blkcg = cgroup_to_blkio_cgroup(cgrp); | |
765 | ||
766 | spin_lock_irq(&blkcg->lock); | |
767 | ||
768 | pn = blkio_policy_search_node(blkcg, newpn->dev); | |
769 | if (!pn) { | |
770 | if (newpn->weight != 0) { | |
771 | blkio_policy_insert_node(blkcg, newpn); | |
772 | keep_newpn = 1; | |
773 | } | |
774 | spin_unlock_irq(&blkcg->lock); | |
775 | goto update_io_group; | |
776 | } | |
777 | ||
778 | if (newpn->weight == 0) { | |
779 | /* weight == 0 means deleteing a specific weight */ | |
780 | blkio_policy_delete_node(pn); | |
781 | spin_unlock_irq(&blkcg->lock); | |
782 | goto update_io_group; | |
783 | } | |
784 | spin_unlock_irq(&blkcg->lock); | |
785 | ||
786 | pn->weight = newpn->weight; | |
787 | ||
788 | update_io_group: | |
789 | /* update weight for each cfqg */ | |
790 | spin_lock(&blkio_list_lock); | |
791 | spin_lock_irq(&blkcg->lock); | |
792 | ||
793 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
794 | if (newpn->dev == blkg->dev) { | |
795 | list_for_each_entry(blkiop, &blkio_list, list) | |
796 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
797 | newpn->weight ? | |
798 | newpn->weight : | |
799 | blkcg->weight); | |
800 | } | |
801 | } | |
802 | ||
803 | spin_unlock_irq(&blkcg->lock); | |
804 | spin_unlock(&blkio_list_lock); | |
805 | ||
806 | free_newpn: | |
807 | if (!keep_newpn) | |
808 | kfree(newpn); | |
809 | free_buf: | |
810 | kfree(buf); | |
811 | return ret; | |
812 | } | |
813 | ||
814 | static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft, | |
815 | struct seq_file *m) | |
816 | { | |
817 | struct blkio_cgroup *blkcg; | |
818 | struct blkio_policy_node *pn; | |
819 | ||
820 | seq_printf(m, "dev\tweight\n"); | |
821 | ||
822 | blkcg = cgroup_to_blkio_cgroup(cgrp); | |
823 | if (list_empty(&blkcg->policy_list)) | |
824 | goto out; | |
825 | ||
826 | spin_lock_irq(&blkcg->lock); | |
827 | list_for_each_entry(pn, &blkcg->policy_list, node) { | |
828 | seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), | |
829 | MINOR(pn->dev), pn->weight); | |
830 | } | |
831 | spin_unlock_irq(&blkcg->lock); | |
832 | ||
833 | out: | |
834 | return 0; | |
835 | } | |
836 | ||
31e4c28d | 837 | struct cftype blkio_files[] = { |
34d0f179 GJ |
838 | { |
839 | .name = "weight_device", | |
840 | .read_seq_string = blkiocg_weight_device_read, | |
841 | .write_string = blkiocg_weight_device_write, | |
842 | .max_write_len = 256, | |
843 | }, | |
31e4c28d VG |
844 | { |
845 | .name = "weight", | |
846 | .read_u64 = blkiocg_weight_read, | |
847 | .write_u64 = blkiocg_weight_write, | |
848 | }, | |
22084190 VG |
849 | { |
850 | .name = "time", | |
303a3acb | 851 | .read_map = blkiocg_time_read, |
22084190 VG |
852 | }, |
853 | { | |
854 | .name = "sectors", | |
303a3acb | 855 | .read_map = blkiocg_sectors_read, |
303a3acb DS |
856 | }, |
857 | { | |
858 | .name = "io_service_bytes", | |
859 | .read_map = blkiocg_io_service_bytes_read, | |
303a3acb DS |
860 | }, |
861 | { | |
862 | .name = "io_serviced", | |
863 | .read_map = blkiocg_io_serviced_read, | |
303a3acb DS |
864 | }, |
865 | { | |
866 | .name = "io_service_time", | |
867 | .read_map = blkiocg_io_service_time_read, | |
303a3acb DS |
868 | }, |
869 | { | |
870 | .name = "io_wait_time", | |
871 | .read_map = blkiocg_io_wait_time_read, | |
84c124da | 872 | }, |
812d4026 DS |
873 | { |
874 | .name = "io_merged", | |
875 | .read_map = blkiocg_io_merged_read, | |
876 | }, | |
cdc1184c DS |
877 | { |
878 | .name = "io_queued", | |
879 | .read_map = blkiocg_io_queued_read, | |
880 | }, | |
84c124da DS |
881 | { |
882 | .name = "reset_stats", | |
883 | .write_u64 = blkiocg_reset_stats, | |
22084190 VG |
884 | }, |
885 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
cdc1184c DS |
886 | { |
887 | .name = "avg_queue_size", | |
888 | .read_map = blkiocg_avg_queue_size_read, | |
889 | }, | |
812df48d DS |
890 | { |
891 | .name = "group_wait_time", | |
892 | .read_map = blkiocg_group_wait_time_read, | |
893 | }, | |
894 | { | |
895 | .name = "idle_time", | |
896 | .read_map = blkiocg_idle_time_read, | |
897 | }, | |
898 | { | |
899 | .name = "empty_time", | |
900 | .read_map = blkiocg_empty_time_read, | |
901 | }, | |
cdc1184c | 902 | { |
22084190 | 903 | .name = "dequeue", |
303a3acb | 904 | .read_map = blkiocg_dequeue_read, |
cdc1184c | 905 | }, |
22084190 | 906 | #endif |
31e4c28d VG |
907 | }; |
908 | ||
909 | static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
910 | { | |
911 | return cgroup_add_files(cgroup, subsys, blkio_files, | |
912 | ARRAY_SIZE(blkio_files)); | |
913 | } | |
914 | ||
915 | static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
916 | { | |
917 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
b1c35769 VG |
918 | unsigned long flags; |
919 | struct blkio_group *blkg; | |
920 | void *key; | |
3e252066 | 921 | struct blkio_policy_type *blkiop; |
34d0f179 | 922 | struct blkio_policy_node *pn, *pntmp; |
b1c35769 VG |
923 | |
924 | rcu_read_lock(); | |
925 | remove_entry: | |
926 | spin_lock_irqsave(&blkcg->lock, flags); | |
927 | ||
928 | if (hlist_empty(&blkcg->blkg_list)) { | |
929 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
930 | goto done; | |
931 | } | |
932 | ||
933 | blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, | |
934 | blkcg_node); | |
935 | key = rcu_dereference(blkg->key); | |
936 | __blkiocg_del_blkio_group(blkg); | |
31e4c28d | 937 | |
b1c35769 VG |
938 | spin_unlock_irqrestore(&blkcg->lock, flags); |
939 | ||
940 | /* | |
941 | * This blkio_group is being unlinked as associated cgroup is going | |
942 | * away. Let all the IO controlling policies know about this event. | |
943 | * | |
944 | * Currently this is static call to one io controlling policy. Once | |
945 | * we have more policies in place, we need some dynamic registration | |
946 | * of callback function. | |
947 | */ | |
3e252066 VG |
948 | spin_lock(&blkio_list_lock); |
949 | list_for_each_entry(blkiop, &blkio_list, list) | |
950 | blkiop->ops.blkio_unlink_group_fn(key, blkg); | |
951 | spin_unlock(&blkio_list_lock); | |
b1c35769 | 952 | goto remove_entry; |
34d0f179 | 953 | |
b1c35769 | 954 | done: |
34d0f179 GJ |
955 | list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) { |
956 | blkio_policy_delete_node(pn); | |
957 | kfree(pn); | |
958 | } | |
31e4c28d | 959 | free_css_id(&blkio_subsys, &blkcg->css); |
b1c35769 | 960 | rcu_read_unlock(); |
67523c48 BB |
961 | if (blkcg != &blkio_root_cgroup) |
962 | kfree(blkcg); | |
31e4c28d VG |
963 | } |
964 | ||
965 | static struct cgroup_subsys_state * | |
966 | blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
967 | { | |
968 | struct blkio_cgroup *blkcg, *parent_blkcg; | |
969 | ||
970 | if (!cgroup->parent) { | |
971 | blkcg = &blkio_root_cgroup; | |
972 | goto done; | |
973 | } | |
974 | ||
975 | /* Currently we do not support hierarchy deeper than two level (0,1) */ | |
976 | parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); | |
977 | if (css_depth(&parent_blkcg->css) > 0) | |
978 | return ERR_PTR(-EINVAL); | |
979 | ||
980 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
981 | if (!blkcg) | |
982 | return ERR_PTR(-ENOMEM); | |
983 | ||
984 | blkcg->weight = BLKIO_WEIGHT_DEFAULT; | |
985 | done: | |
986 | spin_lock_init(&blkcg->lock); | |
987 | INIT_HLIST_HEAD(&blkcg->blkg_list); | |
988 | ||
34d0f179 | 989 | INIT_LIST_HEAD(&blkcg->policy_list); |
31e4c28d VG |
990 | return &blkcg->css; |
991 | } | |
992 | ||
993 | /* | |
994 | * We cannot support shared io contexts, as we have no mean to support | |
995 | * two tasks with the same ioc in two different groups without major rework | |
996 | * of the main cic data structures. For now we allow a task to change | |
997 | * its cgroup only if it's the only owner of its ioc. | |
998 | */ | |
999 | static int blkiocg_can_attach(struct cgroup_subsys *subsys, | |
1000 | struct cgroup *cgroup, struct task_struct *tsk, | |
1001 | bool threadgroup) | |
1002 | { | |
1003 | struct io_context *ioc; | |
1004 | int ret = 0; | |
1005 | ||
1006 | /* task_lock() is needed to avoid races with exit_io_context() */ | |
1007 | task_lock(tsk); | |
1008 | ioc = tsk->io_context; | |
1009 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) | |
1010 | ret = -EINVAL; | |
1011 | task_unlock(tsk); | |
1012 | ||
1013 | return ret; | |
1014 | } | |
1015 | ||
1016 | static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, | |
1017 | struct cgroup *prev, struct task_struct *tsk, | |
1018 | bool threadgroup) | |
1019 | { | |
1020 | struct io_context *ioc; | |
1021 | ||
1022 | task_lock(tsk); | |
1023 | ioc = tsk->io_context; | |
1024 | if (ioc) | |
1025 | ioc->cgroup_changed = 1; | |
1026 | task_unlock(tsk); | |
1027 | } | |
1028 | ||
3e252066 VG |
1029 | void blkio_policy_register(struct blkio_policy_type *blkiop) |
1030 | { | |
1031 | spin_lock(&blkio_list_lock); | |
1032 | list_add_tail(&blkiop->list, &blkio_list); | |
1033 | spin_unlock(&blkio_list_lock); | |
1034 | } | |
1035 | EXPORT_SYMBOL_GPL(blkio_policy_register); | |
1036 | ||
1037 | void blkio_policy_unregister(struct blkio_policy_type *blkiop) | |
1038 | { | |
1039 | spin_lock(&blkio_list_lock); | |
1040 | list_del_init(&blkiop->list); | |
1041 | spin_unlock(&blkio_list_lock); | |
1042 | } | |
1043 | EXPORT_SYMBOL_GPL(blkio_policy_unregister); | |
67523c48 BB |
1044 | |
1045 | static int __init init_cgroup_blkio(void) | |
1046 | { | |
1047 | return cgroup_load_subsys(&blkio_subsys); | |
1048 | } | |
1049 | ||
1050 | static void __exit exit_cgroup_blkio(void) | |
1051 | { | |
1052 | cgroup_unload_subsys(&blkio_subsys); | |
1053 | } | |
1054 | ||
1055 | module_init(init_cgroup_blkio); | |
1056 | module_exit(exit_cgroup_blkio); | |
1057 | MODULE_LICENSE("GPL"); |