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> |
31e4c28d | 19 | #include "blk-cgroup.h" |
3e252066 | 20 | |
84c124da DS |
21 | #define MAX_KEY_LEN 100 |
22 | ||
3e252066 VG |
23 | static DEFINE_SPINLOCK(blkio_list_lock); |
24 | static LIST_HEAD(blkio_list); | |
b1c35769 | 25 | |
31e4c28d | 26 | struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT }; |
9d6a986c VG |
27 | EXPORT_SYMBOL_GPL(blkio_root_cgroup); |
28 | ||
67523c48 BB |
29 | static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *, |
30 | struct cgroup *); | |
31 | static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *, | |
32 | struct task_struct *, bool); | |
33 | static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *, | |
34 | struct cgroup *, struct task_struct *, bool); | |
35 | static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *); | |
36 | static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *); | |
37 | ||
38 | struct cgroup_subsys blkio_subsys = { | |
39 | .name = "blkio", | |
40 | .create = blkiocg_create, | |
41 | .can_attach = blkiocg_can_attach, | |
42 | .attach = blkiocg_attach, | |
43 | .destroy = blkiocg_destroy, | |
44 | .populate = blkiocg_populate, | |
45 | #ifdef CONFIG_BLK_CGROUP | |
46 | /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */ | |
47 | .subsys_id = blkio_subsys_id, | |
48 | #endif | |
49 | .use_id = 1, | |
50 | .module = THIS_MODULE, | |
51 | }; | |
52 | EXPORT_SYMBOL_GPL(blkio_subsys); | |
53 | ||
31e4c28d VG |
54 | struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup) |
55 | { | |
56 | return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id), | |
57 | struct blkio_cgroup, css); | |
58 | } | |
9d6a986c | 59 | EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup); |
31e4c28d | 60 | |
84c124da DS |
61 | void blkio_group_init(struct blkio_group *blkg) |
62 | { | |
63 | spin_lock_init(&blkg->stats_lock); | |
64 | } | |
65 | EXPORT_SYMBOL_GPL(blkio_group_init); | |
66 | ||
9195291e DS |
67 | /* |
68 | * Add to the appropriate stat variable depending on the request type. | |
69 | * This should be called with the blkg->stats_lock held. | |
70 | */ | |
84c124da DS |
71 | static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction, |
72 | bool sync) | |
9195291e | 73 | { |
84c124da DS |
74 | if (direction) |
75 | stat[BLKIO_STAT_WRITE] += add; | |
9195291e | 76 | else |
84c124da DS |
77 | stat[BLKIO_STAT_READ] += add; |
78 | if (sync) | |
79 | stat[BLKIO_STAT_SYNC] += add; | |
9195291e | 80 | else |
84c124da | 81 | stat[BLKIO_STAT_ASYNC] += add; |
9195291e DS |
82 | } |
83 | ||
303a3acb | 84 | void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time) |
22084190 | 85 | { |
303a3acb DS |
86 | unsigned long flags; |
87 | ||
88 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
89 | blkg->stats.time += time; | |
90 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
22084190 | 91 | } |
303a3acb | 92 | EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); |
22084190 | 93 | |
84c124da DS |
94 | void blkiocg_update_dispatch_stats(struct blkio_group *blkg, |
95 | uint64_t bytes, bool direction, bool sync) | |
9195291e DS |
96 | { |
97 | struct blkio_group_stats *stats; | |
98 | unsigned long flags; | |
99 | ||
100 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
101 | stats = &blkg->stats; | |
84c124da DS |
102 | stats->sectors += bytes >> 9; |
103 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction, | |
104 | sync); | |
105 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes, | |
106 | direction, sync); | |
9195291e DS |
107 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
108 | } | |
84c124da | 109 | EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats); |
9195291e | 110 | |
84c124da DS |
111 | void blkiocg_update_completion_stats(struct blkio_group *blkg, |
112 | uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) | |
9195291e DS |
113 | { |
114 | struct blkio_group_stats *stats; | |
115 | unsigned long flags; | |
116 | unsigned long long now = sched_clock(); | |
117 | ||
118 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
119 | stats = &blkg->stats; | |
84c124da DS |
120 | if (time_after64(now, io_start_time)) |
121 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME], | |
122 | now - io_start_time, direction, sync); | |
123 | if (time_after64(io_start_time, start_time)) | |
124 | blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME], | |
125 | io_start_time - start_time, direction, sync); | |
9195291e DS |
126 | spin_unlock_irqrestore(&blkg->stats_lock, flags); |
127 | } | |
84c124da | 128 | EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); |
9195291e | 129 | |
812d4026 DS |
130 | void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, |
131 | bool sync) | |
132 | { | |
133 | unsigned long flags; | |
134 | ||
135 | spin_lock_irqsave(&blkg->stats_lock, flags); | |
136 | blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction, | |
137 | sync); | |
138 | spin_unlock_irqrestore(&blkg->stats_lock, flags); | |
139 | } | |
140 | EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); | |
141 | ||
31e4c28d | 142 | void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, |
22084190 | 143 | struct blkio_group *blkg, void *key, dev_t dev) |
31e4c28d VG |
144 | { |
145 | unsigned long flags; | |
146 | ||
147 | spin_lock_irqsave(&blkcg->lock, flags); | |
148 | rcu_assign_pointer(blkg->key, key); | |
b1c35769 | 149 | blkg->blkcg_id = css_id(&blkcg->css); |
31e4c28d VG |
150 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); |
151 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
2868ef7b VG |
152 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
153 | /* Need to take css reference ? */ | |
154 | cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path)); | |
155 | #endif | |
22084190 | 156 | blkg->dev = dev; |
31e4c28d | 157 | } |
9d6a986c | 158 | EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group); |
31e4c28d | 159 | |
b1c35769 VG |
160 | static void __blkiocg_del_blkio_group(struct blkio_group *blkg) |
161 | { | |
162 | hlist_del_init_rcu(&blkg->blkcg_node); | |
163 | blkg->blkcg_id = 0; | |
164 | } | |
165 | ||
166 | /* | |
167 | * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1 | |
168 | * indicating that blk_group was unhashed by the time we got to it. | |
169 | */ | |
31e4c28d VG |
170 | int blkiocg_del_blkio_group(struct blkio_group *blkg) |
171 | { | |
b1c35769 VG |
172 | struct blkio_cgroup *blkcg; |
173 | unsigned long flags; | |
174 | struct cgroup_subsys_state *css; | |
175 | int ret = 1; | |
176 | ||
177 | rcu_read_lock(); | |
178 | css = css_lookup(&blkio_subsys, blkg->blkcg_id); | |
179 | if (!css) | |
180 | goto out; | |
181 | ||
182 | blkcg = container_of(css, struct blkio_cgroup, css); | |
183 | spin_lock_irqsave(&blkcg->lock, flags); | |
184 | if (!hlist_unhashed(&blkg->blkcg_node)) { | |
185 | __blkiocg_del_blkio_group(blkg); | |
186 | ret = 0; | |
187 | } | |
188 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
189 | out: | |
190 | rcu_read_unlock(); | |
191 | return ret; | |
31e4c28d | 192 | } |
9d6a986c | 193 | EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group); |
31e4c28d VG |
194 | |
195 | /* called under rcu_read_lock(). */ | |
196 | struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) | |
197 | { | |
198 | struct blkio_group *blkg; | |
199 | struct hlist_node *n; | |
200 | void *__key; | |
201 | ||
202 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
203 | __key = blkg->key; | |
204 | if (__key == key) | |
205 | return blkg; | |
206 | } | |
207 | ||
208 | return NULL; | |
209 | } | |
9d6a986c | 210 | EXPORT_SYMBOL_GPL(blkiocg_lookup_group); |
31e4c28d VG |
211 | |
212 | #define SHOW_FUNCTION(__VAR) \ | |
213 | static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \ | |
214 | struct cftype *cftype) \ | |
215 | { \ | |
216 | struct blkio_cgroup *blkcg; \ | |
217 | \ | |
218 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
219 | return (u64)blkcg->__VAR; \ | |
220 | } | |
221 | ||
222 | SHOW_FUNCTION(weight); | |
223 | #undef SHOW_FUNCTION | |
224 | ||
225 | static int | |
226 | blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) | |
227 | { | |
228 | struct blkio_cgroup *blkcg; | |
f8d461d6 VG |
229 | struct blkio_group *blkg; |
230 | struct hlist_node *n; | |
3e252066 | 231 | struct blkio_policy_type *blkiop; |
31e4c28d VG |
232 | |
233 | if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX) | |
234 | return -EINVAL; | |
235 | ||
236 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
bcf4dd43 | 237 | spin_lock(&blkio_list_lock); |
f8d461d6 | 238 | spin_lock_irq(&blkcg->lock); |
31e4c28d | 239 | blkcg->weight = (unsigned int)val; |
3e252066 | 240 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { |
3e252066 VG |
241 | list_for_each_entry(blkiop, &blkio_list, list) |
242 | blkiop->ops.blkio_update_group_weight_fn(blkg, | |
243 | blkcg->weight); | |
3e252066 | 244 | } |
f8d461d6 | 245 | spin_unlock_irq(&blkcg->lock); |
bcf4dd43 | 246 | spin_unlock(&blkio_list_lock); |
31e4c28d VG |
247 | return 0; |
248 | } | |
249 | ||
303a3acb | 250 | static int |
84c124da | 251 | blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val) |
303a3acb DS |
252 | { |
253 | struct blkio_cgroup *blkcg; | |
254 | struct blkio_group *blkg; | |
255 | struct hlist_node *n; | |
256 | struct blkio_group_stats *stats; | |
257 | ||
258 | blkcg = cgroup_to_blkio_cgroup(cgroup); | |
259 | spin_lock_irq(&blkcg->lock); | |
260 | hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) { | |
261 | spin_lock(&blkg->stats_lock); | |
262 | stats = &blkg->stats; | |
263 | memset(stats, 0, sizeof(struct blkio_group_stats)); | |
264 | spin_unlock(&blkg->stats_lock); | |
265 | } | |
266 | spin_unlock_irq(&blkcg->lock); | |
267 | return 0; | |
268 | } | |
269 | ||
84c124da DS |
270 | static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str, |
271 | int chars_left, bool diskname_only) | |
303a3acb | 272 | { |
84c124da | 273 | snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev)); |
303a3acb DS |
274 | chars_left -= strlen(str); |
275 | if (chars_left <= 0) { | |
276 | printk(KERN_WARNING | |
277 | "Possibly incorrect cgroup stat display format"); | |
278 | return; | |
279 | } | |
84c124da DS |
280 | if (diskname_only) |
281 | return; | |
303a3acb | 282 | switch (type) { |
84c124da | 283 | case BLKIO_STAT_READ: |
303a3acb DS |
284 | strlcat(str, " Read", chars_left); |
285 | break; | |
84c124da | 286 | case BLKIO_STAT_WRITE: |
303a3acb DS |
287 | strlcat(str, " Write", chars_left); |
288 | break; | |
84c124da | 289 | case BLKIO_STAT_SYNC: |
303a3acb DS |
290 | strlcat(str, " Sync", chars_left); |
291 | break; | |
84c124da | 292 | case BLKIO_STAT_ASYNC: |
303a3acb DS |
293 | strlcat(str, " Async", chars_left); |
294 | break; | |
84c124da | 295 | case BLKIO_STAT_TOTAL: |
303a3acb DS |
296 | strlcat(str, " Total", chars_left); |
297 | break; | |
298 | default: | |
299 | strlcat(str, " Invalid", chars_left); | |
300 | } | |
301 | } | |
302 | ||
84c124da DS |
303 | static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val, |
304 | struct cgroup_map_cb *cb, dev_t dev) | |
305 | { | |
306 | blkio_get_key_name(0, dev, str, chars_left, true); | |
307 | cb->fill(cb, str, val); | |
308 | return val; | |
309 | } | |
303a3acb | 310 | |
84c124da DS |
311 | /* This should be called with blkg->stats_lock held */ |
312 | static uint64_t blkio_get_stat(struct blkio_group *blkg, | |
313 | struct cgroup_map_cb *cb, dev_t dev, enum stat_type type) | |
303a3acb DS |
314 | { |
315 | uint64_t disk_total; | |
316 | char key_str[MAX_KEY_LEN]; | |
84c124da DS |
317 | enum stat_sub_type sub_type; |
318 | ||
319 | if (type == BLKIO_STAT_TIME) | |
320 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
321 | blkg->stats.time, cb, dev); | |
322 | if (type == BLKIO_STAT_SECTORS) | |
323 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
324 | blkg->stats.sectors, cb, dev); | |
325 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
326 | if (type == BLKIO_STAT_DEQUEUE) | |
327 | return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, | |
328 | blkg->stats.dequeue, cb, dev); | |
329 | #endif | |
303a3acb | 330 | |
84c124da DS |
331 | for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL; |
332 | sub_type++) { | |
333 | blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false); | |
334 | cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]); | |
303a3acb | 335 | } |
84c124da DS |
336 | disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] + |
337 | blkg->stats.stat_arr[type][BLKIO_STAT_WRITE]; | |
338 | blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false); | |
303a3acb DS |
339 | cb->fill(cb, key_str, disk_total); |
340 | return disk_total; | |
341 | } | |
342 | ||
84c124da | 343 | #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \ |
22084190 | 344 | static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \ |
303a3acb | 345 | struct cftype *cftype, struct cgroup_map_cb *cb) \ |
22084190 VG |
346 | { \ |
347 | struct blkio_cgroup *blkcg; \ | |
348 | struct blkio_group *blkg; \ | |
349 | struct hlist_node *n; \ | |
303a3acb | 350 | uint64_t cgroup_total = 0; \ |
22084190 VG |
351 | \ |
352 | if (!cgroup_lock_live_group(cgroup)) \ | |
353 | return -ENODEV; \ | |
354 | \ | |
355 | blkcg = cgroup_to_blkio_cgroup(cgroup); \ | |
356 | rcu_read_lock(); \ | |
357 | hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\ | |
303a3acb DS |
358 | if (blkg->dev) { \ |
359 | spin_lock_irq(&blkg->stats_lock); \ | |
84c124da DS |
360 | cgroup_total += blkio_get_stat(blkg, cb, \ |
361 | blkg->dev, type); \ | |
303a3acb DS |
362 | spin_unlock_irq(&blkg->stats_lock); \ |
363 | } \ | |
22084190 | 364 | } \ |
303a3acb DS |
365 | if (show_total) \ |
366 | cb->fill(cb, "Total", cgroup_total); \ | |
22084190 VG |
367 | rcu_read_unlock(); \ |
368 | cgroup_unlock(); \ | |
369 | return 0; \ | |
370 | } | |
371 | ||
84c124da DS |
372 | SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0); |
373 | SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0); | |
374 | SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1); | |
375 | SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1); | |
376 | SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1); | |
377 | SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1); | |
812d4026 | 378 | SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1); |
22084190 | 379 | #ifdef CONFIG_DEBUG_BLK_CGROUP |
84c124da | 380 | SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0); |
22084190 VG |
381 | #endif |
382 | #undef SHOW_FUNCTION_PER_GROUP | |
383 | ||
384 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
9195291e | 385 | void blkiocg_update_dequeue_stats(struct blkio_group *blkg, |
22084190 VG |
386 | unsigned long dequeue) |
387 | { | |
303a3acb | 388 | blkg->stats.dequeue += dequeue; |
22084190 | 389 | } |
9195291e | 390 | EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats); |
22084190 VG |
391 | #endif |
392 | ||
31e4c28d VG |
393 | struct cftype blkio_files[] = { |
394 | { | |
395 | .name = "weight", | |
396 | .read_u64 = blkiocg_weight_read, | |
397 | .write_u64 = blkiocg_weight_write, | |
398 | }, | |
22084190 VG |
399 | { |
400 | .name = "time", | |
303a3acb | 401 | .read_map = blkiocg_time_read, |
22084190 VG |
402 | }, |
403 | { | |
404 | .name = "sectors", | |
303a3acb | 405 | .read_map = blkiocg_sectors_read, |
303a3acb DS |
406 | }, |
407 | { | |
408 | .name = "io_service_bytes", | |
409 | .read_map = blkiocg_io_service_bytes_read, | |
303a3acb DS |
410 | }, |
411 | { | |
412 | .name = "io_serviced", | |
413 | .read_map = blkiocg_io_serviced_read, | |
303a3acb DS |
414 | }, |
415 | { | |
416 | .name = "io_service_time", | |
417 | .read_map = blkiocg_io_service_time_read, | |
303a3acb DS |
418 | }, |
419 | { | |
420 | .name = "io_wait_time", | |
421 | .read_map = blkiocg_io_wait_time_read, | |
84c124da | 422 | }, |
812d4026 DS |
423 | { |
424 | .name = "io_merged", | |
425 | .read_map = blkiocg_io_merged_read, | |
426 | }, | |
84c124da DS |
427 | { |
428 | .name = "reset_stats", | |
429 | .write_u64 = blkiocg_reset_stats, | |
22084190 VG |
430 | }, |
431 | #ifdef CONFIG_DEBUG_BLK_CGROUP | |
432 | { | |
433 | .name = "dequeue", | |
303a3acb | 434 | .read_map = blkiocg_dequeue_read, |
22084190 VG |
435 | }, |
436 | #endif | |
31e4c28d VG |
437 | }; |
438 | ||
439 | static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
440 | { | |
441 | return cgroup_add_files(cgroup, subsys, blkio_files, | |
442 | ARRAY_SIZE(blkio_files)); | |
443 | } | |
444 | ||
445 | static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
446 | { | |
447 | struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); | |
b1c35769 VG |
448 | unsigned long flags; |
449 | struct blkio_group *blkg; | |
450 | void *key; | |
3e252066 | 451 | struct blkio_policy_type *blkiop; |
b1c35769 VG |
452 | |
453 | rcu_read_lock(); | |
454 | remove_entry: | |
455 | spin_lock_irqsave(&blkcg->lock, flags); | |
456 | ||
457 | if (hlist_empty(&blkcg->blkg_list)) { | |
458 | spin_unlock_irqrestore(&blkcg->lock, flags); | |
459 | goto done; | |
460 | } | |
461 | ||
462 | blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group, | |
463 | blkcg_node); | |
464 | key = rcu_dereference(blkg->key); | |
465 | __blkiocg_del_blkio_group(blkg); | |
31e4c28d | 466 | |
b1c35769 VG |
467 | spin_unlock_irqrestore(&blkcg->lock, flags); |
468 | ||
469 | /* | |
470 | * This blkio_group is being unlinked as associated cgroup is going | |
471 | * away. Let all the IO controlling policies know about this event. | |
472 | * | |
473 | * Currently this is static call to one io controlling policy. Once | |
474 | * we have more policies in place, we need some dynamic registration | |
475 | * of callback function. | |
476 | */ | |
3e252066 VG |
477 | spin_lock(&blkio_list_lock); |
478 | list_for_each_entry(blkiop, &blkio_list, list) | |
479 | blkiop->ops.blkio_unlink_group_fn(key, blkg); | |
480 | spin_unlock(&blkio_list_lock); | |
b1c35769 VG |
481 | goto remove_entry; |
482 | done: | |
31e4c28d | 483 | free_css_id(&blkio_subsys, &blkcg->css); |
b1c35769 | 484 | rcu_read_unlock(); |
67523c48 BB |
485 | if (blkcg != &blkio_root_cgroup) |
486 | kfree(blkcg); | |
31e4c28d VG |
487 | } |
488 | ||
489 | static struct cgroup_subsys_state * | |
490 | blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup) | |
491 | { | |
492 | struct blkio_cgroup *blkcg, *parent_blkcg; | |
493 | ||
494 | if (!cgroup->parent) { | |
495 | blkcg = &blkio_root_cgroup; | |
496 | goto done; | |
497 | } | |
498 | ||
499 | /* Currently we do not support hierarchy deeper than two level (0,1) */ | |
500 | parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent); | |
501 | if (css_depth(&parent_blkcg->css) > 0) | |
502 | return ERR_PTR(-EINVAL); | |
503 | ||
504 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
505 | if (!blkcg) | |
506 | return ERR_PTR(-ENOMEM); | |
507 | ||
508 | blkcg->weight = BLKIO_WEIGHT_DEFAULT; | |
509 | done: | |
510 | spin_lock_init(&blkcg->lock); | |
511 | INIT_HLIST_HEAD(&blkcg->blkg_list); | |
512 | ||
513 | return &blkcg->css; | |
514 | } | |
515 | ||
516 | /* | |
517 | * We cannot support shared io contexts, as we have no mean to support | |
518 | * two tasks with the same ioc in two different groups without major rework | |
519 | * of the main cic data structures. For now we allow a task to change | |
520 | * its cgroup only if it's the only owner of its ioc. | |
521 | */ | |
522 | static int blkiocg_can_attach(struct cgroup_subsys *subsys, | |
523 | struct cgroup *cgroup, struct task_struct *tsk, | |
524 | bool threadgroup) | |
525 | { | |
526 | struct io_context *ioc; | |
527 | int ret = 0; | |
528 | ||
529 | /* task_lock() is needed to avoid races with exit_io_context() */ | |
530 | task_lock(tsk); | |
531 | ioc = tsk->io_context; | |
532 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) | |
533 | ret = -EINVAL; | |
534 | task_unlock(tsk); | |
535 | ||
536 | return ret; | |
537 | } | |
538 | ||
539 | static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, | |
540 | struct cgroup *prev, struct task_struct *tsk, | |
541 | bool threadgroup) | |
542 | { | |
543 | struct io_context *ioc; | |
544 | ||
545 | task_lock(tsk); | |
546 | ioc = tsk->io_context; | |
547 | if (ioc) | |
548 | ioc->cgroup_changed = 1; | |
549 | task_unlock(tsk); | |
550 | } | |
551 | ||
3e252066 VG |
552 | void blkio_policy_register(struct blkio_policy_type *blkiop) |
553 | { | |
554 | spin_lock(&blkio_list_lock); | |
555 | list_add_tail(&blkiop->list, &blkio_list); | |
556 | spin_unlock(&blkio_list_lock); | |
557 | } | |
558 | EXPORT_SYMBOL_GPL(blkio_policy_register); | |
559 | ||
560 | void blkio_policy_unregister(struct blkio_policy_type *blkiop) | |
561 | { | |
562 | spin_lock(&blkio_list_lock); | |
563 | list_del_init(&blkiop->list); | |
564 | spin_unlock(&blkio_list_lock); | |
565 | } | |
566 | EXPORT_SYMBOL_GPL(blkio_policy_unregister); | |
67523c48 BB |
567 | |
568 | static int __init init_cgroup_blkio(void) | |
569 | { | |
570 | return cgroup_load_subsys(&blkio_subsys); | |
571 | } | |
572 | ||
573 | static void __exit exit_cgroup_blkio(void) | |
574 | { | |
575 | cgroup_unload_subsys(&blkio_subsys); | |
576 | } | |
577 | ||
578 | module_init(init_cgroup_blkio); | |
579 | module_exit(exit_cgroup_blkio); | |
580 | MODULE_LICENSE("GPL"); |