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> |
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); | |
0f3942a3 JA |
379 | if (css) { |
380 | blkcg = container_of(css, struct blkio_cgroup, css); | |
381 | spin_lock_irqsave(&blkcg->lock, flags); | |
382 | if (!hlist_unhashed(&blkg->blkcg_node)) { | |
383 | __blkiocg_del_blkio_group(blkg); | |
384 | ret = 0; | |
385 | } | |
386 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
b1c35769 | 387 | } |
0f3942a3 | 388 | |
b1c35769 VG |
389 | rcu_read_unlock(); |
390 | return ret; | |
31e4c28d | 391 | } |
9d6a986c | 392 | EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); |
31e4c28d VG |
393 | |
394 | /* called under rcu_read_lock(). */ | |
395 | struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) | |
396 | { | |
397 | struct blkio_group *blkg; | |
398 | struct hlist_node *n; | |
399 | void *__key; | |
400 | ||
401 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
402 | __key = blkg->key; | |
403 | if (__key == key) | |
404 | return blkg; | |
405 | } | |
406 | ||
407 | return NULL; | |
408 | } | |
9d6a986c | 409 | EXPORT_SYMBOL_GPL(blkiocg_lookup_group); |
31e4c28d VG |
410 | |
411 | #define SHOW_FUNCTION(__VAR) \ | |
412 | static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ | |
413 | struct cftype *cftype) \ | |
414 | { \ | |
415 | struct blkio_cgroup *blkcg; \ | |
416 | \ | |
417 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
418 | return (u64)blkcg->__VAR; \ | |
419 | } | |
420 | ||
421 | SHOW_FUNCTION(weight); | |
422 | #undef SHOW_FUNCTION | |
423 | ||
424 | static int | |
425 | blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) | |
426 | { | |
427 | struct blkio_cgroup *blkcg; | |
f8d461d6 VG |
428 | struct blkio_group *blkg; |
429 | struct hlist_node *n; | |
3e252066 | 430 | struct blkio_policy_type *blkiop; |
34d0f179 | 431 | struct blkio_policy_node *pn; |
31e4c28d VG |
432 | |
433 | if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) | |
434 | return -EINVAL; | |
435 | ||
436 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
bcf4dd43 | 437 | spin_lock(&blkio_list_lock); |
f8d461d6 | 438 | spin_lock_irq(&blkcg->lock); |
31e4c28d | 439 | blkcg->weight = (unsigned int)val; |
34d0f179 | 440 | |
3e252066 | 441 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
34d0f179 GJ |
442 | pn = blkio_policy_search_node(blkcg, blkg->dev); |
443 | ||
444 | if (pn) | |
445 | continue; | |
446 | ||
3e252066 VG |
447 | list_for_each_entry(blkiop, &blkio_list, list) |
448 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
449 | blkcg->weight); | |
3e252066 | 450 | } |
f8d461d6 | 451 | spin_unlock_irq(&blkcg->lock); |
bcf4dd43 | 452 | spin_unlock(&blkio_list_lock); |
31e4c28d VG |
453 | return 0; |
454 | } | |
455 | ||
303a3acb | 456 | static int |
84c124da | 457 | blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) |
303a3acb DS |
458 | { |
459 | struct blkio_cgroup *blkcg; | |
460 | struct blkio_group *blkg; | |
812df48d | 461 | struct blkio_group_stats *stats; |
303a3acb | 462 | struct hlist_node *n; |
cdc1184c DS |
463 | uint64_t queued[BLKIO_STAT_TOTAL]; |
464 | int i; | |
812df48d DS |
465 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
466 | bool idling, waiting, empty; | |
467 | unsigned long long now = sched_clock(); | |
468 | #endif | |
303a3acb DS |
469 | |
470 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
471 | spin_lock_irq(&blkcg->lock); | |
472 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
473 | spin_lock(&blkg->stats_lock); | |
812df48d DS |
474 | stats = &blkg->stats; |
475 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
476 | idling = blkio_blkg_idling(stats); | |
477 | waiting = blkio_blkg_waiting(stats); | |
478 | empty = blkio_blkg_empty(stats); | |
479 | #endif | |
cdc1184c | 480 | for (i = 0; i < BLKIO_STAT_TOTAL; i++) |
812df48d DS |
481 | queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i]; |
482 | memset(stats, 0, sizeof(struct blkio_group_stats)); | |
cdc1184c | 483 | for (i = 0; i < BLKIO_STAT_TOTAL; i++) |
812df48d DS |
484 | stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i]; |
485 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
486 | if (idling) { | |
487 | blkio_mark_blkg_idling(stats); | |
488 | stats->start_idle_time = now; | |
489 | } | |
490 | if (waiting) { | |
491 | blkio_mark_blkg_waiting(stats); | |
492 | stats->start_group_wait_time = now; | |
493 | } | |
494 | if (empty) { | |
495 | blkio_mark_blkg_empty(stats); | |
496 | stats->start_empty_time = now; | |
497 | } | |
498 | #endif | |
303a3acb DS |
499 | spin_unlock(&blkg->stats_lock); |
500 | } | |
501 | spin_unlock_irq(&blkcg->lock); | |
502 | return 0; | |
503 | } | |
504 | ||
84c124da DS |
505 | static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, |
506 | int chars_left, bool diskname_only) | |
303a3acb | 507 | { |
84c124da | 508 | snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); |
303a3acb DS |
509 | chars_left -= strlen(str); |
510 | if (chars_left <= 0) { | |
511 | printk(KERN_WARNING | |
512 | "Possibly incorrect cgroup stat display format"); | |
513 | return; | |
514 | } | |
84c124da DS |
515 | if (diskname_only) |
516 | return; | |
303a3acb | 517 | switch (type) { |
84c124da | 518 | case BLKIO_STAT_READ: |
303a3acb DS |
519 | strlcat(str, " Read", chars_left); |
520 | break; | |
84c124da | 521 | case BLKIO_STAT_WRITE: |
303a3acb DS |
522 | strlcat(str, " Write", chars_left); |
523 | break; | |
84c124da | 524 | case BLKIO_STAT_SYNC: |
303a3acb DS |
525 | strlcat(str, " Sync", chars_left); |
526 | break; | |
84c124da | 527 | case BLKIO_STAT_ASYNC: |
303a3acb DS |
528 | strlcat(str, " Async", chars_left); |
529 | break; | |
84c124da | 530 | case BLKIO_STAT_TOTAL: |
303a3acb DS |
531 | strlcat(str, " Total", chars_left); |
532 | break; | |
533 | default: | |
534 | strlcat(str, " Invalid", chars_left); | |
535 | } | |
536 | } | |
537 | ||
84c124da DS |
538 | static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, |
539 | struct cgroup_map_cb *cb, dev_t dev) | |
540 | { | |
541 | blkio_get_key_name(0, dev, str, chars_left, true); | |
542 | cb->fill(cb, str, val); | |
543 | return val; | |
544 | } | |
303a3acb | 545 | |
84c124da DS |
546 | /* This should be called with blkg->stats_lock held */ |
547 | static uint64_t blkio_get_stat(struct blkio_group *blkg, | |
548 | struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) | |
303a3acb DS |
549 | { |
550 | uint64_t disk_total; | |
551 | char key_str[MAX_KEY_LEN]; | |
84c124da DS |
552 | enum stat_sub_type sub_type; |
553 | ||
554 | if (type == BLKIO_STAT_TIME) | |
555 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
556 | blkg->stats.time, cb, dev); | |
557 | if (type == BLKIO_STAT_SECTORS) | |
558 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
559 | blkg->stats.sectors, cb, dev); | |
560 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
cdc1184c DS |
561 | if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { |
562 | uint64_t sum = blkg->stats.avg_queue_size_sum; | |
563 | uint64_t samples = blkg->stats.avg_queue_size_samples; | |
564 | if (samples) | |
565 | do_div(sum, samples); | |
566 | else | |
567 | sum = 0; | |
568 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev); | |
569 | } | |
812df48d DS |
570 | if (type == BLKIO_STAT_GROUP_WAIT_TIME) |
571 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
572 | blkg->stats.group_wait_time, cb, dev); | |
573 | if (type == BLKIO_STAT_IDLE_TIME) | |
574 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
575 | blkg->stats.idle_time, cb, dev); | |
576 | if (type == BLKIO_STAT_EMPTY_TIME) | |
577 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
578 | blkg->stats.empty_time, cb, dev); | |
84c124da DS |
579 | if (type == BLKIO_STAT_DEQUEUE) |
580 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
581 | blkg->stats.dequeue, cb, dev); | |
582 | #endif | |
303a3acb | 583 | |
84c124da DS |
584 | for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; |
585 | sub_type++) { | |
586 | blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); | |
587 | cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); | |
303a3acb | 588 | } |
84c124da DS |
589 | disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + |
590 | blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; | |
591 | blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); | |
303a3acb DS |
592 | cb->fill(cb, key_str, disk_total); |
593 | return disk_total; | |
594 | } | |
595 | ||
84c124da | 596 | #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \ |
22084190 | 597 | static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ |
303a3acb | 598 | struct cftype *cftype, struct cgroup_map_cb *cb) \ |
22084190 VG |
599 | { \ |
600 | struct blkio_cgroup *blkcg; \ | |
601 | struct blkio_group *blkg; \ | |
602 | struct hlist_node *n; \ | |
303a3acb | 603 | uint64_t cgroup_total = 0; \ |
22084190 VG |
604 | \ |
605 | if (!cgroup_lock_live_group(cgroup)) \ | |
606 | return -ENODEV; \ | |
607 | \ | |
608 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
609 | rcu_read_lock(); \ | |
610 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ | |
303a3acb DS |
611 | if (blkg->dev) { \ |
612 | spin_lock_irq(&blkg->stats_lock); \ | |
84c124da DS |
613 | cgroup_total += blkio_get_stat(blkg, cb, \ |
614 | blkg->dev, type); \ | |
303a3acb DS |
615 | spin_unlock_irq(&blkg->stats_lock); \ |
616 | } \ | |
22084190 | 617 | } \ |
303a3acb DS |
618 | if (show_total) \ |
619 | cb->fill(cb, "Total", cgroup_total); \ | |
22084190 VG |
620 | rcu_read_unlock(); \ |
621 | cgroup_unlock(); \ | |
622 | return 0; \ | |
623 | } | |
624 | ||
84c124da DS |
625 | SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0); |
626 | SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0); | |
627 | SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1); | |
628 | SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1); | |
629 | SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1); | |
630 | SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1); | |
812d4026 | 631 | SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1); |
cdc1184c | 632 | SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1); |
22084190 | 633 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
84c124da | 634 | SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0); |
cdc1184c | 635 | SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0); |
812df48d DS |
636 | SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0); |
637 | SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0); | |
638 | SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0); | |
22084190 VG |
639 | #endif |
640 | #undef SHOW_FUNCTION_PER_GROUP | |
641 | ||
34d0f179 GJ |
642 | static int blkio_check_dev_num(dev_t dev) |
643 | { | |
644 | int part = 0; | |
645 | struct gendisk *disk; | |
646 | ||
647 | disk = get_gendisk(dev, &part); | |
648 | if (!disk || part) | |
649 | return -ENODEV; | |
650 | ||
651 | return 0; | |
652 | } | |
653 | ||
654 | static int blkio_policy_parse_and_set(char *buf, | |
655 | struct blkio_policy_node *newpn) | |
656 | { | |
657 | char *s[4], *p, *major_s = NULL, *minor_s = NULL; | |
658 | int ret; | |
659 | unsigned long major, minor, temp; | |
660 | int i = 0; | |
661 | dev_t dev; | |
662 | ||
663 | memset(s, 0, sizeof(s)); | |
664 | ||
665 | while ((p = strsep(&buf, " ")) != NULL) { | |
666 | if (!*p) | |
667 | continue; | |
668 | ||
669 | s[i++] = p; | |
670 | ||
671 | /* Prevent from inputing too many things */ | |
672 | if (i == 3) | |
673 | break; | |
674 | } | |
675 | ||
676 | if (i != 2) | |
677 | return -EINVAL; | |
678 | ||
679 | p = strsep(&s[0], ":"); | |
680 | if (p != NULL) | |
681 | major_s = p; | |
682 | else | |
683 | return -EINVAL; | |
684 | ||
685 | minor_s = s[0]; | |
686 | if (!minor_s) | |
687 | return -EINVAL; | |
688 | ||
689 | ret = strict_strtoul(major_s, 10, &major); | |
690 | if (ret) | |
691 | return -EINVAL; | |
692 | ||
693 | ret = strict_strtoul(minor_s, 10, &minor); | |
694 | if (ret) | |
695 | return -EINVAL; | |
696 | ||
697 | dev = MKDEV(major, minor); | |
698 | ||
699 | ret = blkio_check_dev_num(dev); | |
700 | if (ret) | |
701 | return ret; | |
702 | ||
703 | newpn->dev = dev; | |
704 | ||
705 | if (s[1] == NULL) | |
706 | return -EINVAL; | |
707 | ||
708 | ret = strict_strtoul(s[1], 10, &temp); | |
709 | if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) || | |
710 | temp > BLKIO_WEIGHT_MAX) | |
711 | return -EINVAL; | |
712 | ||
713 | newpn->weight = temp; | |
714 | ||
715 | return 0; | |
716 | } | |
717 | ||
718 | unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg, | |
719 | dev_t dev) | |
720 | { | |
721 | struct blkio_policy_node *pn; | |
722 | ||
723 | pn = blkio_policy_search_node(blkcg, dev); | |
724 | if (pn) | |
725 | return pn->weight; | |
726 | else | |
727 | return blkcg->weight; | |
728 | } | |
729 | EXPORT_SYMBOL_GPL(blkcg_get_weight); | |
730 | ||
731 | ||
732 | static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft, | |
733 | const char *buffer) | |
734 | { | |
735 | int ret = 0; | |
736 | char *buf; | |
737 | struct blkio_policy_node *newpn, *pn; | |
738 | struct blkio_cgroup *blkcg; | |
739 | struct blkio_group *blkg; | |
740 | int keep_newpn = 0; | |
741 | struct hlist_node *n; | |
742 | struct blkio_policy_type *blkiop; | |
743 | ||
744 | buf = kstrdup(buffer, GFP_KERNEL); | |
745 | if (!buf) | |
746 | return -ENOMEM; | |
747 | ||
748 | newpn = kzalloc(sizeof(*newpn), GFP_KERNEL); | |
749 | if (!newpn) { | |
750 | ret = -ENOMEM; | |
751 | goto free_buf; | |
752 | } | |
753 | ||
754 | ret = blkio_policy_parse_and_set(buf, newpn); | |
755 | if (ret) | |
756 | goto free_newpn; | |
757 | ||
758 | blkcg = cgroup_to_blkio_cgroup(cgrp); | |
759 | ||
760 | spin_lock_irq(&blkcg->lock); | |
761 | ||
762 | pn = blkio_policy_search_node(blkcg, newpn->dev); | |
763 | if (!pn) { | |
764 | if (newpn->weight != 0) { | |
765 | blkio_policy_insert_node(blkcg, newpn); | |
766 | keep_newpn = 1; | |
767 | } | |
768 | spin_unlock_irq(&blkcg->lock); | |
769 | goto update_io_group; | |
770 | } | |
771 | ||
772 | if (newpn->weight == 0) { | |
773 | /* weight == 0 means deleteing a specific weight */ | |
774 | blkio_policy_delete_node(pn); | |
775 | spin_unlock_irq(&blkcg->lock); | |
776 | goto update_io_group; | |
777 | } | |
778 | spin_unlock_irq(&blkcg->lock); | |
779 | ||
780 | pn->weight = newpn->weight; | |
781 | ||
782 | update_io_group: | |
783 | /* update weight for each cfqg */ | |
784 | spin_lock(&blkio_list_lock); | |
785 | spin_lock_irq(&blkcg->lock); | |
786 | ||
787 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
788 | if (newpn->dev == blkg->dev) { | |
789 | list_for_each_entry(blkiop, &blkio_list, list) | |
790 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
791 | newpn->weight ? | |
792 | newpn->weight : | |
793 | blkcg->weight); | |
794 | } | |
795 | } | |
796 | ||
797 | spin_unlock_irq(&blkcg->lock); | |
798 | spin_unlock(&blkio_list_lock); | |
799 | ||
800 | free_newpn: | |
801 | if (!keep_newpn) | |
802 | kfree(newpn); | |
803 | free_buf: | |
804 | kfree(buf); | |
805 | return ret; | |
806 | } | |
807 | ||
808 | static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft, | |
809 | struct seq_file *m) | |
810 | { | |
811 | struct blkio_cgroup *blkcg; | |
812 | struct blkio_policy_node *pn; | |
813 | ||
814 | seq_printf(m, "dev\tweight\n"); | |
815 | ||
816 | blkcg = cgroup_to_blkio_cgroup(cgrp); | |
0f3942a3 JA |
817 | if (!list_empty(&blkcg->policy_list)) { |
818 | spin_lock_irq(&blkcg->lock); | |
819 | list_for_each_entry(pn, &blkcg->policy_list, node) { | |
820 | seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev), | |
821 | MINOR(pn->dev), pn->weight); | |
822 | } | |
823 | spin_unlock_irq(&blkcg->lock); | |
34d0f179 | 824 | } |
34d0f179 | 825 | |
34d0f179 GJ |
826 | return 0; |
827 | } | |
828 | ||
31e4c28d | 829 | struct cftype blkio_files[] = { |
34d0f179 GJ |
830 | { |
831 | .name = "weight_device", | |
832 | .read_seq_string = blkiocg_weight_device_read, | |
833 | .write_string = blkiocg_weight_device_write, | |
834 | .max_write_len = 256, | |
835 | }, | |
31e4c28d VG |
836 | { |
837 | .name = "weight", | |
838 | .read_u64 = blkiocg_weight_read, | |
839 | .write_u64 = blkiocg_weight_write, | |
840 | }, | |
22084190 VG |
841 | { |
842 | .name = "time", | |
303a3acb | 843 | .read_map = blkiocg_time_read, |
22084190 VG |
844 | }, |
845 | { | |
846 | .name = "sectors", | |
303a3acb | 847 | .read_map = blkiocg_sectors_read, |
303a3acb DS |
848 | }, |
849 | { | |
850 | .name = "io_service_bytes", | |
851 | .read_map = blkiocg_io_service_bytes_read, | |
303a3acb DS |
852 | }, |
853 | { | |
854 | .name = "io_serviced", | |
855 | .read_map = blkiocg_io_serviced_read, | |
303a3acb DS |
856 | }, |
857 | { | |
858 | .name = "io_service_time", | |
859 | .read_map = blkiocg_io_service_time_read, | |
303a3acb DS |
860 | }, |
861 | { | |
862 | .name = "io_wait_time", | |
863 | .read_map = blkiocg_io_wait_time_read, | |
84c124da | 864 | }, |
812d4026 DS |
865 | { |
866 | .name = "io_merged", | |
867 | .read_map = blkiocg_io_merged_read, | |
868 | }, | |
cdc1184c DS |
869 | { |
870 | .name = "io_queued", | |
871 | .read_map = blkiocg_io_queued_read, | |
872 | }, | |
84c124da DS |
873 | { |
874 | .name = "reset_stats", | |
875 | .write_u64 = blkiocg_reset_stats, | |
22084190 VG |
876 | }, |
877 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
cdc1184c DS |
878 | { |
879 | .name = "avg_queue_size", | |
880 | .read_map = blkiocg_avg_queue_size_read, | |
881 | }, | |
812df48d DS |
882 | { |
883 | .name = "group_wait_time", | |
884 | .read_map = blkiocg_group_wait_time_read, | |
885 | }, | |
886 | { | |
887 | .name = "idle_time", | |
888 | .read_map = blkiocg_idle_time_read, | |
889 | }, | |
890 | { | |
891 | .name = "empty_time", | |
892 | .read_map = blkiocg_empty_time_read, | |
893 | }, | |
cdc1184c | 894 | { |
22084190 | 895 | .name = "dequeue", |
303a3acb | 896 | .read_map = blkiocg_dequeue_read, |
cdc1184c | 897 | }, |
22084190 | 898 | #endif |
31e4c28d VG |
899 | }; |
900 | ||
901 | static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
902 | { | |
903 | return cgroup_add_files(cgroup, subsys, blkio_files, | |
904 | ARRAY_SIZE(blkio_files)); | |
905 | } | |
906 | ||
907 | static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
908 | { | |
909 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
b1c35769 VG |
910 | unsigned long flags; |
911 | struct blkio_group *blkg; | |
912 | void *key; | |
3e252066 | 913 | struct blkio_policy_type *blkiop; |
34d0f179 | 914 | struct blkio_policy_node *pn, *pntmp; |
b1c35769 VG |
915 | |
916 | rcu_read_lock(); | |
0f3942a3 JA |
917 | do { |
918 | spin_lock_irqsave(&blkcg->lock, flags); | |
b1c35769 | 919 | |
0f3942a3 JA |
920 | if (hlist_empty(&blkcg->blkg_list)) { |
921 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
922 | break; | |
923 | } | |
b1c35769 | 924 | |
0f3942a3 JA |
925 | blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, |
926 | blkcg_node); | |
927 | key = rcu_dereference(blkg->key); | |
928 | __blkiocg_del_blkio_group(blkg); | |
31e4c28d | 929 | |
0f3942a3 | 930 | spin_unlock_irqrestore(&blkcg->lock, flags); |
b1c35769 | 931 | |
0f3942a3 JA |
932 | /* |
933 | * This blkio_group is being unlinked as associated cgroup is | |
934 | * going away. Let all the IO controlling policies know about | |
935 | * this event. Currently this is static call to one io | |
936 | * controlling policy. Once we have more policies in place, we | |
937 | * need some dynamic registration of callback function. | |
938 | */ | |
939 | spin_lock(&blkio_list_lock); | |
940 | list_for_each_entry(blkiop, &blkio_list, list) | |
941 | blkiop->ops.blkio_unlink_group_fn(key, blkg); | |
942 | spin_unlock(&blkio_list_lock); | |
943 | } while (1); | |
34d0f179 | 944 | |
34d0f179 GJ |
945 | list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) { |
946 | blkio_policy_delete_node(pn); | |
947 | kfree(pn); | |
948 | } | |
0f3942a3 | 949 | |
31e4c28d | 950 | free_css_id(&blkio_subsys, &blkcg->css); |
b1c35769 | 951 | rcu_read_unlock(); |
67523c48 BB |
952 | if (blkcg != &blkio_root_cgroup) |
953 | kfree(blkcg); | |
31e4c28d VG |
954 | } |
955 | ||
956 | static struct cgroup_subsys_state * | |
957 | blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
958 | { | |
0341509f LZ |
959 | struct blkio_cgroup *blkcg; |
960 | struct cgroup *parent = cgroup->parent; | |
31e4c28d | 961 | |
0341509f | 962 | if (!parent) { |
31e4c28d VG |
963 | blkcg = &blkio_root_cgroup; |
964 | goto done; | |
965 | } | |
966 | ||
967 | /* Currently we do not support hierarchy deeper than two level (0,1) */ | |
0341509f | 968 | if (parent != cgroup->top_cgroup) |
31e4c28d VG |
969 | return ERR_PTR(-EINVAL); |
970 | ||
971 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
972 | if (!blkcg) | |
973 | return ERR_PTR(-ENOMEM); | |
974 | ||
975 | blkcg->weight = BLKIO_WEIGHT_DEFAULT; | |
976 | done: | |
977 | spin_lock_init(&blkcg->lock); | |
978 | INIT_HLIST_HEAD(&blkcg->blkg_list); | |
979 | ||
34d0f179 | 980 | INIT_LIST_HEAD(&blkcg->policy_list); |
31e4c28d VG |
981 | return &blkcg->css; |
982 | } | |
983 | ||
984 | /* | |
985 | * We cannot support shared io contexts, as we have no mean to support | |
986 | * two tasks with the same ioc in two different groups without major rework | |
987 | * of the main cic data structures. For now we allow a task to change | |
988 | * its cgroup only if it's the only owner of its ioc. | |
989 | */ | |
990 | static int blkiocg_can_attach(struct cgroup_subsys *subsys, | |
991 | struct cgroup *cgroup, struct task_struct *tsk, | |
992 | bool threadgroup) | |
993 | { | |
994 | struct io_context *ioc; | |
995 | int ret = 0; | |
996 | ||
997 | /* task_lock() is needed to avoid races with exit_io_context() */ | |
998 | task_lock(tsk); | |
999 | ioc = tsk->io_context; | |
1000 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) | |
1001 | ret = -EINVAL; | |
1002 | task_unlock(tsk); | |
1003 | ||
1004 | return ret; | |
1005 | } | |
1006 | ||
1007 | static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, | |
1008 | struct cgroup *prev, struct task_struct *tsk, | |
1009 | bool threadgroup) | |
1010 | { | |
1011 | struct io_context *ioc; | |
1012 | ||
1013 | task_lock(tsk); | |
1014 | ioc = tsk->io_context; | |
1015 | if (ioc) | |
1016 | ioc->cgroup_changed = 1; | |
1017 | task_unlock(tsk); | |
1018 | } | |
1019 | ||
3e252066 VG |
1020 | void blkio_policy_register(struct blkio_policy_type *blkiop) |
1021 | { | |
1022 | spin_lock(&blkio_list_lock); | |
1023 | list_add_tail(&blkiop->list, &blkio_list); | |
1024 | spin_unlock(&blkio_list_lock); | |
1025 | } | |
1026 | EXPORT_SYMBOL_GPL(blkio_policy_register); | |
1027 | ||
1028 | void blkio_policy_unregister(struct blkio_policy_type *blkiop) | |
1029 | { | |
1030 | spin_lock(&blkio_list_lock); | |
1031 | list_del_init(&blkiop->list); | |
1032 | spin_unlock(&blkio_list_lock); | |
1033 | } | |
1034 | EXPORT_SYMBOL_GPL(blkio_policy_unregister); | |
67523c48 BB |
1035 | |
1036 | static int __init init_cgroup_blkio(void) | |
1037 | { | |
1038 | return cgroup_load_subsys(&blkio_subsys); | |
1039 | } | |
1040 | ||
1041 | static void __exit exit_cgroup_blkio(void) | |
1042 | { | |
1043 | cgroup_unload_subsys(&blkio_subsys); | |
1044 | } | |
1045 | ||
1046 | module_init(init_cgroup_blkio); | |
1047 | module_exit(exit_cgroup_blkio); | |
1048 | MODULE_LICENSE("GPL"); |