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> |
5a0e3ad6 | 19 | #include <linux/slab.h> |
31e4c28d | 20 | #include "blk-cgroup.h" |
34d0f179 | 21 | #include <linux/genhd.h> |
3e252066 | 22 | |
84c124da DS |
23 | #define MAX_KEY_LEN 100 |
24 | ||
3e252066 VG |
25 | static DEFINE_SPINLOCK(blkio_list_lock); |
26 | static LIST_HEAD(blkio_list); | |
b1c35769 | 27 | |
31e4c28d | 28 | struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; |
9d6a986c VG |
29 | EXPORT_SYMBOL_GPL(blkio_root_cgroup); |
30 | ||
67523c48 BB |
31 | static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, |
32 | struct cgroup *); | |
33 | static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, | |
34 | struct task_struct *, bool); | |
35 | static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *, | |
36 | struct cgroup *, struct task_struct *, bool); | |
37 | static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); | |
38 | static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); | |
39 | ||
40 | struct cgroup_subsys blkio_subsys = { | |
41 | .name = "blkio", | |
42 | .create = blkiocg_create, | |
43 | .can_attach = blkiocg_can_attach, | |
44 | .attach = blkiocg_attach, | |
45 | .destroy = blkiocg_destroy, | |
46 | .populate = blkiocg_populate, | |
47 | #ifdef CONFIG_BLK_CGROUP | |
48 | /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ | |
49 | .subsys_id = blkio_subsys_id, | |
50 | #endif | |
51 | .use_id = 1, | |
52 | .module = THIS_MODULE, | |
53 | }; | |
54 | EXPORT_SYMBOL_GPL(blkio_subsys); | |
55 | ||
34d0f179 GJ |
56 | static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg, |
57 | struct blkio_policy_node *pn) | |
58 | { | |
59 | list_add(&pn->node, &blkcg->policy_list); | |
60 | } | |
61 | ||
62 | /* Must be called with blkcg->lock held */ | |
63 | static inline void blkio_policy_delete_node(struct blkio_policy_node *pn) | |
64 | { | |
65 | list_del(&pn->node); | |
66 | } | |
67 | ||
68 | /* Must be called with blkcg->lock held */ | |
69 | static struct blkio_policy_node * | |
70 | blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev) | |
71 | { | |
72 | struct blkio_policy_node *pn; | |
73 | ||
74 | list_for_each_entry(pn, &blkcg->policy_list, node) { | |
75 | if (pn->dev == dev) | |
76 | return pn; | |
77 | } | |
78 | ||
79 | return NULL; | |
80 | } | |
81 | ||
31e4c28d VG |
82 | struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) |
83 | { | |
84 | return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), | |
85 | struct blkio_cgroup, css); | |
86 | } | |
9d6a986c | 87 | EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); |
31e4c28d | 88 | |
9195291e DS |
89 | /* |
90 | * Add to the appropriate stat variable depending on the request type. | |
91 | * This should be called with the blkg->stats_lock held. | |
92 | */ | |
84c124da DS |
93 | static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction, |
94 | bool sync) | |
9195291e | 95 | { |
84c124da DS |
96 | if (direction) |
97 | stat[BLKIO_STAT_WRITE] += add; | |
9195291e | 98 | else |
84c124da DS |
99 | stat[BLKIO_STAT_READ] += add; |
100 | if (sync) | |
101 | stat[BLKIO_STAT_SYNC] += add; | |
9195291e | 102 | else |
84c124da | 103 | stat[BLKIO_STAT_ASYNC] += add; |
9195291e DS |
104 | } |
105 | ||
cdc1184c DS |
106 | /* |
107 | * Decrements the appropriate stat variable if non-zero depending on the | |
108 | * request type. Panics on value being zero. | |
109 | * This should be called with the blkg->stats_lock held. | |
110 | */ | |
111 | static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync) | |
112 | { | |
113 | if (direction) { | |
114 | BUG_ON(stat[BLKIO_STAT_WRITE] == 0); | |
115 | stat[BLKIO_STAT_WRITE]--; | |
116 | } else { | |
117 | BUG_ON(stat[BLKIO_STAT_READ] == 0); | |
118 | stat[BLKIO_STAT_READ]--; | |
119 | } | |
120 | if (sync) { | |
121 | BUG_ON(stat[BLKIO_STAT_SYNC] == 0); | |
122 | stat[BLKIO_STAT_SYNC]--; | |
123 | } else { | |
124 | BUG_ON(stat[BLKIO_STAT_ASYNC] == 0); | |
125 | stat[BLKIO_STAT_ASYNC]--; | |
126 | } | |
127 | } | |
128 | ||
129 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
812df48d DS |
130 | /* This should be called with the blkg->stats_lock held. */ |
131 | static void blkio_set_start_group_wait_time(struct blkio_group *blkg, | |
132 | struct blkio_group *curr_blkg) | |
133 | { | |
134 | if (blkio_blkg_waiting(&blkg->stats)) | |
135 | return; | |
136 | if (blkg == curr_blkg) | |
137 | return; | |
138 | blkg->stats.start_group_wait_time = sched_clock(); | |
139 | blkio_mark_blkg_waiting(&blkg->stats); | |
140 | } | |
141 | ||
142 | /* This should be called with the blkg->stats_lock held. */ | |
143 | static void blkio_update_group_wait_time(struct blkio_group_stats *stats) | |
144 | { | |
145 | unsigned long long now; | |
146 | ||
147 | if (!blkio_blkg_waiting(stats)) | |
148 | return; | |
149 | ||
150 | now = sched_clock(); | |
151 | if (time_after64(now, stats->start_group_wait_time)) | |
152 | stats->group_wait_time += now - stats->start_group_wait_time; | |
153 | blkio_clear_blkg_waiting(stats); | |
154 | } | |
155 | ||
156 | /* This should be called with the blkg->stats_lock held. */ | |
157 | static void blkio_end_empty_time(struct blkio_group_stats *stats) | |
158 | { | |
159 | unsigned long long now; | |
160 | ||
161 | if (!blkio_blkg_empty(stats)) | |
162 | return; | |
163 | ||
164 | now = sched_clock(); | |
165 | if (time_after64(now, stats->start_empty_time)) | |
166 | stats->empty_time += now - stats->start_empty_time; | |
167 | blkio_clear_blkg_empty(stats); | |
168 | } | |
169 | ||
170 | void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) | |
171 | { | |
172 | unsigned long flags; | |
173 | ||
174 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
175 | BUG_ON(blkio_blkg_idling(&blkg->stats)); | |
176 | blkg->stats.start_idle_time = sched_clock(); | |
177 | blkio_mark_blkg_idling(&blkg->stats); | |
178 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
179 | } | |
180 | EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats); | |
181 | ||
182 | void blkiocg_update_idle_time_stats(struct blkio_group *blkg) | |
183 | { | |
184 | unsigned long flags; | |
185 | unsigned long long now; | |
186 | struct blkio_group_stats *stats; | |
187 | ||
188 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
189 | stats = &blkg->stats; | |
190 | if (blkio_blkg_idling(stats)) { | |
191 | now = sched_clock(); | |
192 | if (time_after64(now, stats->start_idle_time)) | |
193 | stats->idle_time += now - stats->start_idle_time; | |
194 | blkio_clear_blkg_idling(stats); | |
195 | } | |
196 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
197 | } | |
198 | EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats); | |
199 | ||
a11cdaa7 | 200 | void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg) |
cdc1184c DS |
201 | { |
202 | unsigned long flags; | |
203 | struct blkio_group_stats *stats; | |
204 | ||
205 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
206 | stats = &blkg->stats; | |
207 | stats->avg_queue_size_sum += | |
208 | stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] + | |
209 | stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]; | |
210 | stats->avg_queue_size_samples++; | |
812df48d | 211 | blkio_update_group_wait_time(stats); |
cdc1184c DS |
212 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
213 | } | |
a11cdaa7 DS |
214 | EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats); |
215 | ||
e5ff082e | 216 | void blkiocg_set_start_empty_time(struct blkio_group *blkg) |
28baf442 DS |
217 | { |
218 | unsigned long flags; | |
219 | struct blkio_group_stats *stats; | |
220 | ||
221 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
222 | stats = &blkg->stats; | |
223 | ||
224 | if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] || | |
225 | stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) { | |
226 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
227 | return; | |
228 | } | |
229 | ||
230 | /* | |
e5ff082e VG |
231 | * group is already marked empty. This can happen if cfqq got new |
232 | * request in parent group and moved to this group while being added | |
233 | * to service tree. Just ignore the event and move on. | |
28baf442 | 234 | */ |
e5ff082e VG |
235 | if(blkio_blkg_empty(stats)) { |
236 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
237 | return; | |
238 | } | |
239 | ||
28baf442 DS |
240 | stats->start_empty_time = sched_clock(); |
241 | blkio_mark_blkg_empty(stats); | |
242 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
243 | } | |
244 | EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time); | |
245 | ||
a11cdaa7 DS |
246 | void blkiocg_update_dequeue_stats(struct blkio_group *blkg, |
247 | unsigned long dequeue) | |
248 | { | |
249 | blkg->stats.dequeue += dequeue; | |
250 | } | |
251 | EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); | |
812df48d DS |
252 | #else |
253 | static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg, | |
254 | struct blkio_group *curr_blkg) {} | |
255 | static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {} | |
cdc1184c DS |
256 | #endif |
257 | ||
a11cdaa7 | 258 | void blkiocg_update_io_add_stats(struct blkio_group *blkg, |
cdc1184c DS |
259 | struct blkio_group *curr_blkg, bool direction, |
260 | bool sync) | |
261 | { | |
262 | unsigned long flags; | |
263 | ||
264 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
265 | blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction, | |
266 | sync); | |
812df48d DS |
267 | blkio_end_empty_time(&blkg->stats); |
268 | blkio_set_start_group_wait_time(blkg, curr_blkg); | |
cdc1184c DS |
269 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
270 | } | |
a11cdaa7 | 271 | EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats); |
cdc1184c | 272 | |
a11cdaa7 | 273 | void blkiocg_update_io_remove_stats(struct blkio_group *blkg, |
cdc1184c DS |
274 | bool direction, bool sync) |
275 | { | |
276 | unsigned long flags; | |
277 | ||
278 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
279 | blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], | |
280 | direction, sync); | |
281 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
282 | } | |
a11cdaa7 | 283 | EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats); |
cdc1184c | 284 | |
303a3acb | 285 | void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time) |
22084190 | 286 | { |
303a3acb DS |
287 | unsigned long flags; |
288 | ||
289 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
290 | blkg->stats.time += time; | |
291 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
22084190 | 292 | } |
303a3acb | 293 | EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); |
22084190 | 294 | |
84c124da DS |
295 | void blkiocg_update_dispatch_stats(struct blkio_group *blkg, |
296 | uint64_t bytes, bool direction, bool sync) | |
9195291e DS |
297 | { |
298 | struct blkio_group_stats *stats; | |
299 | unsigned long flags; | |
300 | ||
301 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
302 | stats = &blkg->stats; | |
84c124da DS |
303 | stats->sectors += bytes >> 9; |
304 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction, | |
305 | sync); | |
306 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes, | |
307 | direction, sync); | |
9195291e DS |
308 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
309 | } | |
84c124da | 310 | EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats); |
9195291e | 311 | |
84c124da DS |
312 | void blkiocg_update_completion_stats(struct blkio_group *blkg, |
313 | uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) | |
9195291e DS |
314 | { |
315 | struct blkio_group_stats *stats; | |
316 | unsigned long flags; | |
317 | unsigned long long now = sched_clock(); | |
318 | ||
319 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
320 | stats = &blkg->stats; | |
84c124da DS |
321 | if (time_after64(now, io_start_time)) |
322 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME], | |
323 | now - io_start_time, direction, sync); | |
324 | if (time_after64(io_start_time, start_time)) | |
325 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME], | |
326 | io_start_time - start_time, direction, sync); | |
9195291e DS |
327 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
328 | } | |
84c124da | 329 | EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); |
9195291e | 330 | |
812d4026 DS |
331 | void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, |
332 | bool sync) | |
333 | { | |
334 | unsigned long flags; | |
335 | ||
336 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
337 | blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction, | |
338 | sync); | |
339 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
340 | } | |
341 | EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); | |
342 | ||
31e4c28d | 343 | void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, |
22084190 | 344 | struct blkio_group *blkg, void *key, dev_t dev) |
31e4c28d VG |
345 | { |
346 | unsigned long flags; | |
347 | ||
348 | spin_lock_irqsave(&blkcg->lock, flags); | |
8d2a91f8 | 349 | spin_lock_init(&blkg->stats_lock); |
31e4c28d | 350 | rcu_assign_pointer(blkg->key, key); |
b1c35769 | 351 | blkg->blkcg_id = css_id(&blkcg->css); |
31e4c28d VG |
352 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); |
353 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
2868ef7b VG |
354 | /* Need to take css reference ? */ |
355 | cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); | |
22084190 | 356 | blkg->dev = dev; |
31e4c28d | 357 | } |
9d6a986c | 358 | EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group); |
31e4c28d | 359 | |
b1c35769 VG |
360 | static void __blkiocg_del_blkio_group(struct blkio_group *blkg) |
361 | { | |
362 | hlist_del_init_rcu(&blkg->blkcg_node); | |
363 | blkg->blkcg_id = 0; | |
364 | } | |
365 | ||
366 | /* | |
367 | * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 | |
368 | * indicating that blk_group was unhashed by the time we got to it. | |
369 | */ | |
31e4c28d VG |
370 | int blkiocg_del_blkio_group(struct blkio_group *blkg) |
371 | { | |
b1c35769 VG |
372 | struct blkio_cgroup *blkcg; |
373 | unsigned long flags; | |
374 | struct cgroup_subsys_state *css; | |
375 | int ret = 1; | |
376 | ||
377 | rcu_read_lock(); | |
378 | css = css_lookup(&blkio_subsys, blkg->blkcg_id); | |
379 | if (!css) | |
380 | goto out; | |
381 | ||
382 | blkcg = container_of(css, struct blkio_cgroup, css); | |
383 | spin_lock_irqsave(&blkcg->lock, flags); | |
384 | if (!hlist_unhashed(&blkg->blkcg_node)) { | |
385 | __blkiocg_del_blkio_group(blkg); | |
386 | ret = 0; | |
387 | } | |
388 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
389 | out: | |
390 | rcu_read_unlock(); | |
391 | return ret; | |
31e4c28d | 392 | } |
9d6a986c | 393 | EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); |
31e4c28d VG |
394 | |
395 | /* called under rcu_read_lock(). */ | |
396 | struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) | |
397 | { | |
398 | struct blkio_group *blkg; | |
399 | struct hlist_node *n; | |
400 | void *__key; | |
401 | ||
402 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
403 | __key = blkg->key; | |
404 | if (__key == key) | |
405 | return blkg; | |
406 | } | |
407 | ||
408 | return NULL; | |
409 | } | |
9d6a986c | 410 | EXPORT_SYMBOL_GPL(blkiocg_lookup_group); |
31e4c28d VG |
411 | |
412 | #define SHOW_FUNCTION(__VAR) \ | |
413 | static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ | |
414 | struct cftype *cftype) \ | |
415 | { \ | |
416 | struct blkio_cgroup *blkcg; \ | |
417 | \ | |
418 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
419 | return (u64)blkcg->__VAR; \ | |
420 | } | |
421 | ||
422 | SHOW_FUNCTION(weight); | |
423 | #undef SHOW_FUNCTION | |
424 | ||
425 | static int | |
426 | blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) | |
427 | { | |
428 | struct blkio_cgroup *blkcg; | |
f8d461d6 VG |
429 | struct blkio_group *blkg; |
430 | struct hlist_node *n; | |
3e252066 | 431 | struct blkio_policy_type *blkiop; |
34d0f179 | 432 | struct blkio_policy_node *pn; |
31e4c28d VG |
433 | |
434 | if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) | |
435 | return -EINVAL; | |
436 | ||
437 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
bcf4dd43 | 438 | spin_lock(&blkio_list_lock); |
f8d461d6 | 439 | spin_lock_irq(&blkcg->lock); |
31e4c28d | 440 | blkcg->weight = (unsigned int)val; |
34d0f179 | 441 | |
3e252066 | 442 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
34d0f179 GJ |
443 | pn = blkio_policy_search_node(blkcg, blkg->dev); |
444 | ||
445 | if (pn) | |
446 | continue; | |
447 | ||
3e252066 VG |
448 | list_for_each_entry(blkiop, &blkio_list, list) |
449 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
450 | blkcg->weight); | |
3e252066 | 451 | } |
f8d461d6 | 452 | spin_unlock_irq(&blkcg->lock); |
bcf4dd43 | 453 | spin_unlock(&blkio_list_lock); |
31e4c28d VG |
454 | return 0; |
455 | } | |
456 | ||
303a3acb | 457 | static int |
84c124da | 458 | blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) |
303a3acb DS |
459 | { |
460 | struct blkio_cgroup *blkcg; | |
461 | struct blkio_group *blkg; | |
812df48d | 462 | struct blkio_group_stats *stats; |
303a3acb | 463 | struct hlist_node *n; |
cdc1184c DS |
464 | uint64_t queued[BLKIO_STAT_TOTAL]; |
465 | int i; | |
812df48d DS |
466 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
467 | bool idling, waiting, empty; | |
468 | unsigned long long now = sched_clock(); | |
469 | #endif | |
303a3acb DS |
470 | |
471 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
472 | spin_lock_irq(&blkcg->lock); | |
473 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
474 | spin_lock(&blkg->stats_lock); | |
812df48d DS |
475 | stats = &blkg->stats; |
476 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
477 | idling = blkio_blkg_idling(stats); | |
478 | waiting = blkio_blkg_waiting(stats); | |
479 | empty = blkio_blkg_empty(stats); | |
480 | #endif | |
cdc1184c | 481 | for (i = 0; i < BLKIO_STAT_TOTAL; i++) |
812df48d DS |
482 | queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i]; |
483 | memset(stats, 0, sizeof(struct blkio_group_stats)); | |
cdc1184c | 484 | for (i = 0; i < BLKIO_STAT_TOTAL; i++) |
812df48d DS |
485 | stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i]; |
486 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
487 | if (idling) { | |
488 | blkio_mark_blkg_idling(stats); | |
489 | stats->start_idle_time = now; | |
490 | } | |
491 | if (waiting) { | |
492 | blkio_mark_blkg_waiting(stats); | |
493 | stats->start_group_wait_time = now; | |
494 | } | |
495 | if (empty) { | |
496 | blkio_mark_blkg_empty(stats); | |
497 | stats->start_empty_time = now; | |
498 | } | |
499 | #endif | |
303a3acb DS |
500 | spin_unlock(&blkg->stats_lock); |
501 | } | |
502 | spin_unlock_irq(&blkcg->lock); | |
503 | return 0; | |
504 | } | |
505 | ||
84c124da DS |
506 | static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, |
507 | int chars_left, bool diskname_only) | |
303a3acb | 508 | { |
84c124da | 509 | snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); |
303a3acb DS |
510 | chars_left -= strlen(str); |
511 | if (chars_left <= 0) { | |
512 | printk(KERN_WARNING | |
513 | "Possibly incorrect cgroup stat display format"); | |
514 | return; | |
515 | } | |
84c124da DS |
516 | if (diskname_only) |
517 | return; | |
303a3acb | 518 | switch (type) { |
84c124da | 519 | case BLKIO_STAT_READ: |
303a3acb DS |
520 | strlcat(str, " Read", chars_left); |
521 | break; | |
84c124da | 522 | case BLKIO_STAT_WRITE: |
303a3acb DS |
523 | strlcat(str, " Write", chars_left); |
524 | break; | |
84c124da | 525 | case BLKIO_STAT_SYNC: |
303a3acb DS |
526 | strlcat(str, " Sync", chars_left); |
527 | break; | |
84c124da | 528 | case BLKIO_STAT_ASYNC: |
303a3acb DS |
529 | strlcat(str, " Async", chars_left); |
530 | break; | |
84c124da | 531 | case BLKIO_STAT_TOTAL: |
303a3acb DS |
532 | strlcat(str, " Total", chars_left); |
533 | break; | |
534 | default: | |
535 | strlcat(str, " Invalid", chars_left); | |
536 | } | |
537 | } | |
538 | ||
84c124da DS |
539 | static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, |
540 | struct cgroup_map_cb *cb, dev_t dev) | |
541 | { | |
542 | blkio_get_key_name(0, dev, str, chars_left, true); | |
543 | cb->fill(cb, str, val); | |
544 | return val; | |
545 | } | |
303a3acb | 546 | |
84c124da DS |
547 | /* This should be called with blkg->stats_lock held */ |
548 | static uint64_t blkio_get_stat(struct blkio_group *blkg, | |
549 | struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) | |
303a3acb DS |
550 | { |
551 | uint64_t disk_total; | |
552 | char key_str[MAX_KEY_LEN]; | |
84c124da DS |
553 | enum stat_sub_type sub_type; |
554 | ||
555 | if (type == BLKIO_STAT_TIME) | |
556 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
557 | blkg->stats.time, cb, dev); | |
558 | if (type == BLKIO_STAT_SECTORS) | |
559 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
560 | blkg->stats.sectors, cb, dev); | |
561 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
cdc1184c DS |
562 | if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { |
563 | uint64_t sum = blkg->stats.avg_queue_size_sum; | |
564 | uint64_t samples = blkg->stats.avg_queue_size_samples; | |
565 | if (samples) | |
566 | do_div(sum, samples); | |
567 | else | |
568 | sum = 0; | |
569 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev); | |
570 | } | |
812df48d DS |
571 | if (type == BLKIO_STAT_GROUP_WAIT_TIME) |
572 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
573 | blkg->stats.group_wait_time, cb, dev); | |
574 | if (type == BLKIO_STAT_IDLE_TIME) | |
575 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
576 | blkg->stats.idle_time, cb, dev); | |
577 | if (type == BLKIO_STAT_EMPTY_TIME) | |
578 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
579 | blkg->stats.empty_time, cb, dev); | |
84c124da DS |
580 | if (type == BLKIO_STAT_DEQUEUE) |
581 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
582 | blkg->stats.dequeue, cb, dev); | |
583 | #endif | |
303a3acb | 584 | |
84c124da DS |
585 | for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; |
586 | sub_type++) { | |
587 | blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); | |
588 | cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); | |
303a3acb | 589 | } |
84c124da DS |
590 | disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + |
591 | blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; | |
592 | blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); | |
303a3acb DS |
593 | cb->fill(cb, key_str, disk_total); |
594 | return disk_total; | |
595 | } | |
596 | ||
84c124da | 597 | #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \ |
22084190 | 598 | static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ |
303a3acb | 599 | struct cftype *cftype, struct cgroup_map_cb *cb) \ |
22084190 VG |
600 | { \ |
601 | struct blkio_cgroup *blkcg; \ | |
602 | struct blkio_group *blkg; \ | |
603 | struct hlist_node *n; \ | |
303a3acb | 604 | uint64_t cgroup_total = 0; \ |
22084190 VG |
605 | \ |
606 | if (!cgroup_lock_live_group(cgroup)) \ | |
607 | return -ENODEV; \ | |
608 | \ | |
609 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
610 | rcu_read_lock(); \ | |
611 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ | |
303a3acb DS |
612 | if (blkg->dev) { \ |
613 | spin_lock_irq(&blkg->stats_lock); \ | |
84c124da DS |
614 | cgroup_total += blkio_get_stat(blkg, cb, \ |
615 | blkg->dev, type); \ | |
303a3acb DS |
616 | spin_unlock_irq(&blkg->stats_lock); \ |
617 | } \ | |
22084190 | 618 | } \ |
303a3acb DS |
619 | if (show_total) \ |
620 | cb->fill(cb, "Total", cgroup_total); \ | |
22084190 VG |
621 | rcu_read_unlock(); \ |
622 | cgroup_unlock(); \ | |
623 | return 0; \ | |
624 | } | |
625 | ||
84c124da DS |
626 | SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0); |
627 | SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0); | |
628 | SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1); | |
629 | SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1); | |
630 | SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1); | |
631 | SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1); | |
812d4026 | 632 | SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1); |
cdc1184c | 633 | SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1); |
22084190 | 634 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
84c124da | 635 | SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0); |
cdc1184c | 636 | SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0); |
812df48d DS |
637 | SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0); |
638 | SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0); | |
639 | SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0); | |
22084190 VG |
640 | #endif |
641 | #undef SHOW_FUNCTION_PER_GROUP | |
642 | ||
34d0f179 GJ |
643 | static int blkio_check_dev_num(dev_t dev) |
644 | { | |
645 | int part = 0; | |
646 | struct gendisk *disk; | |
647 | ||
648 | disk = get_gendisk(dev, &part); | |
649 | if (!disk || part) | |
650 | return -ENODEV; | |
651 | ||
652 | return 0; | |
653 | } | |
654 | ||
655 | static int blkio_policy_parse_and_set(char *buf, | |
656 | struct blkio_policy_node *newpn) | |
657 | { | |
658 | char *s[4], *p, *major_s = NULL, *minor_s = NULL; | |
659 | int ret; | |
660 | unsigned long major, minor, temp; | |
661 | int i = 0; | |
662 | dev_t dev; | |
663 | ||
664 | memset(s, 0, sizeof(s)); | |
665 | ||
666 | while ((p = strsep(&buf, " ")) != NULL) { | |
667 | if (!*p) | |
668 | continue; | |
669 | ||
670 | s[i++] = p; | |
671 | ||
672 | /* Prevent from inputing too many things */ | |
673 | if (i == 3) | |
674 | break; | |
675 | } | |
676 | ||
677 | if (i != 2) | |
678 | return -EINVAL; | |
679 | ||
680 | p = strsep(&s[0], ":"); | |
681 | if (p != NULL) | |
682 | major_s = p; | |
683 | else | |
684 | return -EINVAL; | |
685 | ||
686 | minor_s = s[0]; | |
687 | if (!minor_s) | |
688 | return -EINVAL; | |
689 | ||
690 | ret = strict_strtoul(major_s, 10, &major); | |
691 | if (ret) | |
692 | return -EINVAL; | |
693 | ||
694 | ret = strict_strtoul(minor_s, 10, &minor); | |
695 | if (ret) | |
696 | return -EINVAL; | |
697 | ||
698 | dev = MKDEV(major, minor); | |
699 | ||
700 | ret = blkio_check_dev_num(dev); | |
701 | if (ret) | |
702 | return ret; | |
703 | ||
704 | newpn->dev = dev; | |
705 | ||
706 | if (s[1] == NULL) | |
707 | return -EINVAL; | |
708 | ||
709 | ret = strict_strtoul(s[1], 10, &temp); | |
710 | if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) || | |
711 | temp > BLKIO_WEIGHT_MAX) | |
712 | return -EINVAL; | |
713 | ||
714 | newpn->weight = temp; | |
715 | ||
716 | return 0; | |
717 | } | |
718 | ||
719 | unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg, | |
720 | dev_t dev) | |
721 | { | |
722 | struct blkio_policy_node *pn; | |
723 | ||
724 | pn = blkio_policy_search_node(blkcg, dev); | |
725 | if (pn) | |
726 | return pn->weight; | |
727 | else | |
728 | return blkcg->weight; | |
729 | } | |
730 | EXPORT_SYMBOL_GPL(blkcg_get_weight); | |
731 | ||
732 | ||
733 | static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft, | |
734 | const char *buffer) | |
735 | { | |
736 | int ret = 0; | |
737 | char *buf; | |
738 | struct blkio_policy_node *newpn, *pn; | |
739 | struct blkio_cgroup *blkcg; | |
740 | struct blkio_group *blkg; | |
741 | int keep_newpn = 0; | |
742 | struct hlist_node *n; | |
743 | struct blkio_policy_type *blkiop; | |
744 | ||
745 | buf = kstrdup(buffer, GFP_KERNEL); | |
746 | if (!buf) | |
747 | return -ENOMEM; | |
748 | ||
749 | newpn = kzalloc(sizeof(*newpn), GFP_KERNEL); | |
750 | if (!newpn) { | |
751 | ret = -ENOMEM; | |
752 | goto free_buf; | |
753 | } | |
754 | ||
755 | ret = blkio_policy_parse_and_set(buf, newpn); | |
756 | if (ret) | |
757 | goto free_newpn; | |
758 | ||
759 | blkcg = cgroup_to_blkio_cgroup(cgrp); | |
760 | ||
761 | spin_lock_irq(&blkcg->lock); | |
762 | ||
763 | pn = blkio_policy_search_node(blkcg, newpn->dev); | |
764 | if (!pn) { | |
765 | if (newpn->weight != 0) { | |
766 | blkio_policy_insert_node(blkcg, newpn); | |
767 | keep_newpn = 1; | |
768 | } | |
769 | spin_unlock_irq(&blkcg->lock); | |
770 | goto update_io_group; | |
771 | } | |
772 | ||
773 | if (newpn->weight == 0) { | |
774 | /* weight == 0 means deleteing a specific weight */ | |
775 | blkio_policy_delete_node(pn); | |
776 | spin_unlock_irq(&blkcg->lock); | |
777 | goto update_io_group; | |
778 | } | |
779 | spin_unlock_irq(&blkcg->lock); | |
780 | ||
781 | pn->weight = newpn->weight; | |
782 | ||
783 | update_io_group: | |
784 | /* update weight for each cfqg */ | |
785 | spin_lock(&blkio_list_lock); | |
786 | spin_lock_irq(&blkcg->lock); | |
787 | ||
788 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
789 | if (newpn->dev == blkg->dev) { | |
790 | list_for_each_entry(blkiop, &blkio_list, list) | |
791 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
792 | newpn->weight ? | |
793 | newpn->weight : | |
794 | blkcg->weight); | |
795 | } | |
796 | } | |
797 | ||
798 | spin_unlock_irq(&blkcg->lock); | |
799 | spin_unlock(&blkio_list_lock); | |
800 | ||
801 | free_newpn: | |
802 | if (!keep_newpn) | |
803 | kfree(newpn); | |
804 | free_buf: | |
805 | kfree(buf); | |
806 | return ret; | |
807 | } | |
808 | ||
809 | static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft, | |
810 | struct seq_file *m) | |
811 | { | |
812 | struct blkio_cgroup *blkcg; | |
813 | struct blkio_policy_node *pn; | |
814 | ||
815 | seq_printf(m, "dev\tweight\n"); | |
816 | ||
817 | blkcg = cgroup_to_blkio_cgroup(cgrp); | |
818 | if (list_empty(&blkcg->policy_list)) | |
819 | goto out; | |
820 | ||
821 | spin_lock_irq(&blkcg->lock); | |
822 | list_for_each_entry(pn, &blkcg->policy_list, node) { | |
823 | seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), | |
824 | MINOR(pn->dev), pn->weight); | |
825 | } | |
826 | spin_unlock_irq(&blkcg->lock); | |
827 | ||
828 | out: | |
829 | return 0; | |
830 | } | |
831 | ||
31e4c28d | 832 | struct cftype blkio_files[] = { |
34d0f179 GJ |
833 | { |
834 | .name = "weight_device", | |
835 | .read_seq_string = blkiocg_weight_device_read, | |
836 | .write_string = blkiocg_weight_device_write, | |
837 | .max_write_len = 256, | |
838 | }, | |
31e4c28d VG |
839 | { |
840 | .name = "weight", | |
841 | .read_u64 = blkiocg_weight_read, | |
842 | .write_u64 = blkiocg_weight_write, | |
843 | }, | |
22084190 VG |
844 | { |
845 | .name = "time", | |
303a3acb | 846 | .read_map = blkiocg_time_read, |
22084190 VG |
847 | }, |
848 | { | |
849 | .name = "sectors", | |
303a3acb | 850 | .read_map = blkiocg_sectors_read, |
303a3acb DS |
851 | }, |
852 | { | |
853 | .name = "io_service_bytes", | |
854 | .read_map = blkiocg_io_service_bytes_read, | |
303a3acb DS |
855 | }, |
856 | { | |
857 | .name = "io_serviced", | |
858 | .read_map = blkiocg_io_serviced_read, | |
303a3acb DS |
859 | }, |
860 | { | |
861 | .name = "io_service_time", | |
862 | .read_map = blkiocg_io_service_time_read, | |
303a3acb DS |
863 | }, |
864 | { | |
865 | .name = "io_wait_time", | |
866 | .read_map = blkiocg_io_wait_time_read, | |
84c124da | 867 | }, |
812d4026 DS |
868 | { |
869 | .name = "io_merged", | |
870 | .read_map = blkiocg_io_merged_read, | |
871 | }, | |
cdc1184c DS |
872 | { |
873 | .name = "io_queued", | |
874 | .read_map = blkiocg_io_queued_read, | |
875 | }, | |
84c124da DS |
876 | { |
877 | .name = "reset_stats", | |
878 | .write_u64 = blkiocg_reset_stats, | |
22084190 VG |
879 | }, |
880 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
cdc1184c DS |
881 | { |
882 | .name = "avg_queue_size", | |
883 | .read_map = blkiocg_avg_queue_size_read, | |
884 | }, | |
812df48d DS |
885 | { |
886 | .name = "group_wait_time", | |
887 | .read_map = blkiocg_group_wait_time_read, | |
888 | }, | |
889 | { | |
890 | .name = "idle_time", | |
891 | .read_map = blkiocg_idle_time_read, | |
892 | }, | |
893 | { | |
894 | .name = "empty_time", | |
895 | .read_map = blkiocg_empty_time_read, | |
896 | }, | |
cdc1184c | 897 | { |
22084190 | 898 | .name = "dequeue", |
303a3acb | 899 | .read_map = blkiocg_dequeue_read, |
cdc1184c | 900 | }, |
22084190 | 901 | #endif |
31e4c28d VG |
902 | }; |
903 | ||
904 | static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
905 | { | |
906 | return cgroup_add_files(cgroup, subsys, blkio_files, | |
907 | ARRAY_SIZE(blkio_files)); | |
908 | } | |
909 | ||
910 | static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
911 | { | |
912 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
b1c35769 VG |
913 | unsigned long flags; |
914 | struct blkio_group *blkg; | |
915 | void *key; | |
3e252066 | 916 | struct blkio_policy_type *blkiop; |
34d0f179 | 917 | struct blkio_policy_node *pn, *pntmp; |
b1c35769 VG |
918 | |
919 | rcu_read_lock(); | |
920 | remove_entry: | |
921 | spin_lock_irqsave(&blkcg->lock, flags); | |
922 | ||
923 | if (hlist_empty(&blkcg->blkg_list)) { | |
924 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
925 | goto done; | |
926 | } | |
927 | ||
928 | blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, | |
929 | blkcg_node); | |
930 | key = rcu_dereference(blkg->key); | |
931 | __blkiocg_del_blkio_group(blkg); | |
31e4c28d | 932 | |
b1c35769 VG |
933 | spin_unlock_irqrestore(&blkcg->lock, flags); |
934 | ||
935 | /* | |
936 | * This blkio_group is being unlinked as associated cgroup is going | |
937 | * away. Let all the IO controlling policies know about this event. | |
938 | * | |
939 | * Currently this is static call to one io controlling policy. Once | |
940 | * we have more policies in place, we need some dynamic registration | |
941 | * of callback function. | |
942 | */ | |
3e252066 VG |
943 | spin_lock(&blkio_list_lock); |
944 | list_for_each_entry(blkiop, &blkio_list, list) | |
945 | blkiop->ops.blkio_unlink_group_fn(key, blkg); | |
946 | spin_unlock(&blkio_list_lock); | |
b1c35769 | 947 | goto remove_entry; |
34d0f179 | 948 | |
b1c35769 | 949 | done: |
34d0f179 GJ |
950 | list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) { |
951 | blkio_policy_delete_node(pn); | |
952 | kfree(pn); | |
953 | } | |
31e4c28d | 954 | free_css_id(&blkio_subsys, &blkcg->css); |
b1c35769 | 955 | rcu_read_unlock(); |
67523c48 BB |
956 | if (blkcg != &blkio_root_cgroup) |
957 | kfree(blkcg); | |
31e4c28d VG |
958 | } |
959 | ||
960 | static struct cgroup_subsys_state * | |
961 | blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
962 | { | |
963 | struct blkio_cgroup *blkcg, *parent_blkcg; | |
964 | ||
965 | if (!cgroup->parent) { | |
966 | blkcg = &blkio_root_cgroup; | |
967 | goto done; | |
968 | } | |
969 | ||
970 | /* Currently we do not support hierarchy deeper than two level (0,1) */ | |
971 | parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); | |
972 | if (css_depth(&parent_blkcg->css) > 0) | |
973 | return ERR_PTR(-EINVAL); | |
974 | ||
975 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
976 | if (!blkcg) | |
977 | return ERR_PTR(-ENOMEM); | |
978 | ||
979 | blkcg->weight = BLKIO_WEIGHT_DEFAULT; | |
980 | done: | |
981 | spin_lock_init(&blkcg->lock); | |
982 | INIT_HLIST_HEAD(&blkcg->blkg_list); | |
983 | ||
34d0f179 | 984 | INIT_LIST_HEAD(&blkcg->policy_list); |
31e4c28d VG |
985 | return &blkcg->css; |
986 | } | |
987 | ||
988 | /* | |
989 | * We cannot support shared io contexts, as we have no mean to support | |
990 | * two tasks with the same ioc in two different groups without major rework | |
991 | * of the main cic data structures. For now we allow a task to change | |
992 | * its cgroup only if it's the only owner of its ioc. | |
993 | */ | |
994 | static int blkiocg_can_attach(struct cgroup_subsys *subsys, | |
995 | struct cgroup *cgroup, struct task_struct *tsk, | |
996 | bool threadgroup) | |
997 | { | |
998 | struct io_context *ioc; | |
999 | int ret = 0; | |
1000 | ||
1001 | /* task_lock() is needed to avoid races with exit_io_context() */ | |
1002 | task_lock(tsk); | |
1003 | ioc = tsk->io_context; | |
1004 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) | |
1005 | ret = -EINVAL; | |
1006 | task_unlock(tsk); | |
1007 | ||
1008 | return ret; | |
1009 | } | |
1010 | ||
1011 | static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, | |
1012 | struct cgroup *prev, struct task_struct *tsk, | |
1013 | bool threadgroup) | |
1014 | { | |
1015 | struct io_context *ioc; | |
1016 | ||
1017 | task_lock(tsk); | |
1018 | ioc = tsk->io_context; | |
1019 | if (ioc) | |
1020 | ioc->cgroup_changed = 1; | |
1021 | task_unlock(tsk); | |
1022 | } | |
1023 | ||
3e252066 VG |
1024 | void blkio_policy_register(struct blkio_policy_type *blkiop) |
1025 | { | |
1026 | spin_lock(&blkio_list_lock); | |
1027 | list_add_tail(&blkiop->list, &blkio_list); | |
1028 | spin_unlock(&blkio_list_lock); | |
1029 | } | |
1030 | EXPORT_SYMBOL_GPL(blkio_policy_register); | |
1031 | ||
1032 | void blkio_policy_unregister(struct blkio_policy_type *blkiop) | |
1033 | { | |
1034 | spin_lock(&blkio_list_lock); | |
1035 | list_del_init(&blkiop->list); | |
1036 | spin_unlock(&blkio_list_lock); | |
1037 | } | |
1038 | EXPORT_SYMBOL_GPL(blkio_policy_unregister); | |
67523c48 BB |
1039 | |
1040 | static int __init init_cgroup_blkio(void) | |
1041 | { | |
1042 | return cgroup_load_subsys(&blkio_subsys); | |
1043 | } | |
1044 | ||
1045 | static void __exit exit_cgroup_blkio(void) | |
1046 | { | |
1047 | cgroup_unload_subsys(&blkio_subsys); | |
1048 | } | |
1049 | ||
1050 | module_init(init_cgroup_blkio); | |
1051 | module_exit(exit_cgroup_blkio); | |
1052 | MODULE_LICENSE("GPL"); |