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[mirror_ubuntu-zesty-kernel.git] / block / blk-cgroup.c
CommitLineData
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		 25static DEFINE_SPINLOCK(blkio_list_lock);
26static LIST_HEAD(blkio_list);
b1c35769 27
31e4c28d 28struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
9d6a986c
VG		 29EXPORT_SYMBOL_GPL(blkio_root_cgroup);
30
67523c48
BB		 31static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
32 struct cgroup *);
33static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
34 struct task_struct *, bool);
35static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
36 struct cgroup *, struct task_struct *, bool);
37static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
38static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
39
062a644d
VG		 40/* for encoding cft->private value on file */
41#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
42/* What policy owns the file, proportional or throttle */
43#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
44#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
45
67523c48
BB		 46struct cgroup_subsys blkio_subsys = {
47 .name = "blkio",
48 .create = blkiocg_create,
49 .can_attach = blkiocg_can_attach,
50 .attach = blkiocg_attach,
51 .destroy = blkiocg_destroy,
52 .populate = blkiocg_populate,
53#ifdef CONFIG_BLK_CGROUP
54 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
55 .subsys_id = blkio_subsys_id,
56#endif
57 .use_id = 1,
58 .module = THIS_MODULE,
59};
60EXPORT_SYMBOL_GPL(blkio_subsys);
61
34d0f179
GJ		 62static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
63 struct blkio_policy_node *pn)
64{
65 list_add(&pn->node, &blkcg->policy_list);
66}
67
062a644d
VG		 68static inline bool cftype_blkg_same_policy(struct cftype *cft,
69 struct blkio_group *blkg)
70{
71 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
72
73 if (blkg->plid == plid)
74 return 1;
75
76 return 0;
77}
78
79/* Determines if policy node matches cgroup file being accessed */
80static inline bool pn_matches_cftype(struct cftype *cft,
81 struct blkio_policy_node *pn)
82{
83 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
84 int fileid = BLKIOFILE_ATTR(cft->private);
85
86 return (plid == pn->plid && fileid == pn->fileid);
87}
88
34d0f179
GJ		 89/* Must be called with blkcg->lock held */
90static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
91{
92 list_del(&pn->node);
93}
94
95/* Must be called with blkcg->lock held */
96static struct blkio_policy_node *
062a644d
VG		 97blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
98 enum blkio_policy_id plid, int fileid)
34d0f179
GJ		 99{
100 struct blkio_policy_node *pn;
101
102 list_for_each_entry(pn, &blkcg->policy_list, node) {
062a644d 103 if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
34d0f179
GJ		 104 return pn;
105 }
106
107 return NULL;
108}
109
31e4c28d
VG		 110struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
111{
112 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
113 struct blkio_cgroup, css);
114}
9d6a986c 115EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
31e4c28d 116
062a644d
VG		 117static inline void
118blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
119{
120 struct blkio_policy_type *blkiop;
121
122 list_for_each_entry(blkiop, &blkio_list, list) {
123 /* If this policy does not own the blkg, do not send updates */
124 if (blkiop->plid != blkg->plid)
125 continue;
126 if (blkiop->ops.blkio_update_group_weight_fn)
fe071437
VG		 127 blkiop->ops.blkio_update_group_weight_fn(blkg->key,
128 blkg, weight);
062a644d
VG		 129 }
130}
131
4c9eefa1
VG		 132static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
133 int fileid)
134{
135 struct blkio_policy_type *blkiop;
136
137 list_for_each_entry(blkiop, &blkio_list, list) {
138
139 /* If this policy does not own the blkg, do not send updates */
140 if (blkiop->plid != blkg->plid)
141 continue;
142
143 if (fileid == BLKIO_THROTL_read_bps_device
144 && blkiop->ops.blkio_update_group_read_bps_fn)
fe071437
VG		 145 blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
146 blkg, bps);
4c9eefa1
VG		 147
148 if (fileid == BLKIO_THROTL_write_bps_device
149 && blkiop->ops.blkio_update_group_write_bps_fn)
fe071437
VG		 150 blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
151 blkg, bps);
4c9eefa1
VG		 152 }
153}
154
7702e8f4
VG		 155static inline void blkio_update_group_iops(struct blkio_group *blkg,
156 unsigned int iops, int fileid)
157{
158 struct blkio_policy_type *blkiop;
159
160 list_for_each_entry(blkiop, &blkio_list, list) {
161
162 /* If this policy does not own the blkg, do not send updates */
163 if (blkiop->plid != blkg->plid)
164 continue;
165
166 if (fileid == BLKIO_THROTL_read_iops_device
167 && blkiop->ops.blkio_update_group_read_iops_fn)
fe071437
VG		 168 blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
169 blkg, iops);
7702e8f4
VG		 170
171 if (fileid == BLKIO_THROTL_write_iops_device
172 && blkiop->ops.blkio_update_group_write_iops_fn)
fe071437
VG		 173 blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
174 blkg,iops);
7702e8f4
VG		 175 }
176}
177
9195291e
DS		 178/*
179 * Add to the appropriate stat variable depending on the request type.
180 * This should be called with the blkg->stats_lock held.
181 */
84c124da
DS		 182static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
183 bool sync)
9195291e 184{
84c124da
DS		 185 if (direction)
186 stat[BLKIO_STAT_WRITE] += add;
9195291e 187 else
84c124da
DS		 188 stat[BLKIO_STAT_READ] += add;
189 if (sync)
190 stat[BLKIO_STAT_SYNC] += add;
9195291e 191 else
84c124da 192 stat[BLKIO_STAT_ASYNC] += add;
9195291e
DS		 193}
194
cdc1184c
DS		 195/*
196 * Decrements the appropriate stat variable if non-zero depending on the
197 * request type. Panics on value being zero.
198 * This should be called with the blkg->stats_lock held.
199 */
200static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
201{
202 if (direction) {
203 BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
204 stat[BLKIO_STAT_WRITE]--;
205 } else {
206 BUG_ON(stat[BLKIO_STAT_READ] == 0);
207 stat[BLKIO_STAT_READ]--;
208 }
209 if (sync) {
210 BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
211 stat[BLKIO_STAT_SYNC]--;
212 } else {
213 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
214 stat[BLKIO_STAT_ASYNC]--;
215 }
216}
217
218#ifdef CONFIG_DEBUG_BLK_CGROUP
812df48d
DS		 219/* This should be called with the blkg->stats_lock held. */
220static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
221 struct blkio_group *curr_blkg)
222{
223 if (blkio_blkg_waiting(&blkg->stats))
224 return;
225 if (blkg == curr_blkg)
226 return;
227 blkg->stats.start_group_wait_time = sched_clock();
228 blkio_mark_blkg_waiting(&blkg->stats);
229}
230
231/* This should be called with the blkg->stats_lock held. */
232static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
233{
234 unsigned long long now;
235
236 if (!blkio_blkg_waiting(stats))
237 return;
238
239 now = sched_clock();
240 if (time_after64(now, stats->start_group_wait_time))
241 stats->group_wait_time += now - stats->start_group_wait_time;
242 blkio_clear_blkg_waiting(stats);
243}
244
245/* This should be called with the blkg->stats_lock held. */
246static void blkio_end_empty_time(struct blkio_group_stats *stats)
247{
248 unsigned long long now;
249
250 if (!blkio_blkg_empty(stats))
251 return;
252
253 now = sched_clock();
254 if (time_after64(now, stats->start_empty_time))
255 stats->empty_time += now - stats->start_empty_time;
256 blkio_clear_blkg_empty(stats);
257}
258
259void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
260{
261 unsigned long flags;
262
263 spin_lock_irqsave(&blkg->stats_lock, flags);
264 BUG_ON(blkio_blkg_idling(&blkg->stats));
265 blkg->stats.start_idle_time = sched_clock();
266 blkio_mark_blkg_idling(&blkg->stats);
267 spin_unlock_irqrestore(&blkg->stats_lock, flags);
268}
269EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
270
271void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
272{
273 unsigned long flags;
274 unsigned long long now;
275 struct blkio_group_stats *stats;
276
277 spin_lock_irqsave(&blkg->stats_lock, flags);
278 stats = &blkg->stats;
279 if (blkio_blkg_idling(stats)) {
280 now = sched_clock();
281 if (time_after64(now, stats->start_idle_time))
282 stats->idle_time += now - stats->start_idle_time;
283 blkio_clear_blkg_idling(stats);
284 }
285 spin_unlock_irqrestore(&blkg->stats_lock, flags);
286}
287EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
288
a11cdaa7 289void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
cdc1184c
DS		 290{
291 unsigned long flags;
292 struct blkio_group_stats *stats;
293
294 spin_lock_irqsave(&blkg->stats_lock, flags);
295 stats = &blkg->stats;
296 stats->avg_queue_size_sum +=
297 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
298 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
299 stats->avg_queue_size_samples++;
812df48d 300 blkio_update_group_wait_time(stats);
cdc1184c
DS		 301 spin_unlock_irqrestore(&blkg->stats_lock, flags);
302}
a11cdaa7
DS		 303EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
304
e5ff082e 305void blkiocg_set_start_empty_time(struct blkio_group *blkg)
28baf442
DS		 306{
307 unsigned long flags;
308 struct blkio_group_stats *stats;
309
310 spin_lock_irqsave(&blkg->stats_lock, flags);
311 stats = &blkg->stats;
312
313 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
314 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
315 spin_unlock_irqrestore(&blkg->stats_lock, flags);
316 return;
317 }
318
319 /*
e5ff082e
VG		 320 * group is already marked empty. This can happen if cfqq got new
321 * request in parent group and moved to this group while being added
322 * to service tree. Just ignore the event and move on.
28baf442 323 */
e5ff082e
VG		 324 if(blkio_blkg_empty(stats)) {
325 spin_unlock_irqrestore(&blkg->stats_lock, flags);
326 return;
327 }
328
28baf442
DS		 329 stats->start_empty_time = sched_clock();
330 blkio_mark_blkg_empty(stats);
331 spin_unlock_irqrestore(&blkg->stats_lock, flags);
332}
333EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
334
a11cdaa7
DS		 335void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
336 unsigned long dequeue)
337{
338 blkg->stats.dequeue += dequeue;
339}
340EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
812df48d
DS		 341#else
342static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
343 struct blkio_group *curr_blkg) {}
344static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
cdc1184c
DS		 345#endif
346
a11cdaa7 347void blkiocg_update_io_add_stats(struct blkio_group *blkg,
cdc1184c
DS		 348 struct blkio_group *curr_blkg, bool direction,
349 bool sync)
350{
351 unsigned long flags;
352
353 spin_lock_irqsave(&blkg->stats_lock, flags);
354 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
355 sync);
812df48d
DS		 356 blkio_end_empty_time(&blkg->stats);
357 blkio_set_start_group_wait_time(blkg, curr_blkg);
cdc1184c
DS		 358 spin_unlock_irqrestore(&blkg->stats_lock, flags);
359}
a11cdaa7 360EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
cdc1184c 361
a11cdaa7 362void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
cdc1184c
DS		 363 bool direction, bool sync)
364{
365 unsigned long flags;
366
367 spin_lock_irqsave(&blkg->stats_lock, flags);
368 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
369 direction, sync);
370 spin_unlock_irqrestore(&blkg->stats_lock, flags);
371}
a11cdaa7 372EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
cdc1184c 373
167400d3
JT		 374void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time,
375 unsigned long unaccounted_time)
22084190 376{
303a3acb
DS		 377 unsigned long flags;
378
379 spin_lock_irqsave(&blkg->stats_lock, flags);
380 blkg->stats.time += time;
167400d3 381 blkg->stats.unaccounted_time += unaccounted_time;
303a3acb 382 spin_unlock_irqrestore(&blkg->stats_lock, flags);
22084190 383}
303a3acb 384EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
22084190 385
84c124da
DS		 386void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
387 uint64_t bytes, bool direction, bool sync)
9195291e
DS		 388{
389 struct blkio_group_stats *stats;
390 unsigned long flags;
391
392 spin_lock_irqsave(&blkg->stats_lock, flags);
393 stats = &blkg->stats;
84c124da
DS		 394 stats->sectors += bytes >> 9;
395 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
396 sync);
397 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
398 direction, sync);
9195291e
DS		 399 spin_unlock_irqrestore(&blkg->stats_lock, flags);
400}
84c124da 401EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
9195291e 402
84c124da
DS		 403void blkiocg_update_completion_stats(struct blkio_group *blkg,
404 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
9195291e
DS		 405{
406 struct blkio_group_stats *stats;
407 unsigned long flags;
408 unsigned long long now = sched_clock();
409
410 spin_lock_irqsave(&blkg->stats_lock, flags);
411 stats = &blkg->stats;
84c124da
DS		 412 if (time_after64(now, io_start_time))
413 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
414 now - io_start_time, direction, sync);
415 if (time_after64(io_start_time, start_time))
416 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
417 io_start_time - start_time, direction, sync);
9195291e
DS		 418 spin_unlock_irqrestore(&blkg->stats_lock, flags);
419}
84c124da 420EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
9195291e 421
812d4026
DS		 422void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
423 bool sync)
424{
425 unsigned long flags;
426
427 spin_lock_irqsave(&blkg->stats_lock, flags);
428 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,
429 sync);
430 spin_unlock_irqrestore(&blkg->stats_lock, flags);
431}
432EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
433
31e4c28d 434void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
062a644d
VG		 435 struct blkio_group *blkg, void *key, dev_t dev,
436 enum blkio_policy_id plid)
31e4c28d
VG		 437{
438 unsigned long flags;
439
440 spin_lock_irqsave(&blkcg->lock, flags);
8d2a91f8 441 spin_lock_init(&blkg->stats_lock);
31e4c28d 442 rcu_assign_pointer(blkg->key, key);
b1c35769 443 blkg->blkcg_id = css_id(&blkcg->css);
31e4c28d 444 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
062a644d 445 blkg->plid = plid;
31e4c28d 446 spin_unlock_irqrestore(&blkcg->lock, flags);
2868ef7b
VG		 447 /* Need to take css reference ? */
448 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
22084190 449 blkg->dev = dev;
31e4c28d 450}
9d6a986c 451EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
31e4c28d 452
b1c35769
VG		 453static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
454{
455 hlist_del_init_rcu(&blkg->blkcg_node);
456 blkg->blkcg_id = 0;
457}
458
459/*
460 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
461 * indicating that blk_group was unhashed by the time we got to it.
462 */
31e4c28d
VG		 463int blkiocg_del_blkio_group(struct blkio_group *blkg)
464{
b1c35769
VG		 465 struct blkio_cgroup *blkcg;
466 unsigned long flags;
467 struct cgroup_subsys_state *css;
468 int ret = 1;
469
470 rcu_read_lock();
471 css = css_lookup(&blkio_subsys, blkg->blkcg_id);
0f3942a3
JA		 472 if (css) {
473 blkcg = container_of(css, struct blkio_cgroup, css);
474 spin_lock_irqsave(&blkcg->lock, flags);
475 if (!hlist_unhashed(&blkg->blkcg_node)) {
476 __blkiocg_del_blkio_group(blkg);
477 ret = 0;
478 }
479 spin_unlock_irqrestore(&blkcg->lock, flags);
b1c35769 480 }
0f3942a3 481
b1c35769
VG		 482 rcu_read_unlock();
483 return ret;
31e4c28d 484}
9d6a986c 485EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
31e4c28d
VG		 486
487/* called under rcu_read_lock(). */
488struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
489{
490 struct blkio_group *blkg;
491 struct hlist_node *n;
492 void *__key;
493
494 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
495 __key = blkg->key;
496 if (__key == key)
497 return blkg;
498 }
499
500 return NULL;
501}
9d6a986c 502EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
31e4c28d 503
303a3acb 504static int
84c124da 505blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
303a3acb
DS		 506{
507 struct blkio_cgroup *blkcg;
508 struct blkio_group *blkg;
812df48d 509 struct blkio_group_stats *stats;
303a3acb 510 struct hlist_node *n;
cdc1184c
DS		 511 uint64_t queued[BLKIO_STAT_TOTAL];
512 int i;
812df48d
DS		 513#ifdef CONFIG_DEBUG_BLK_CGROUP
514 bool idling, waiting, empty;
515 unsigned long long now = sched_clock();
516#endif
303a3acb
DS		 517
518 blkcg = cgroup_to_blkio_cgroup(cgroup);
519 spin_lock_irq(&blkcg->lock);
520 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
521 spin_lock(&blkg->stats_lock);
812df48d
DS		 522 stats = &blkg->stats;
523#ifdef CONFIG_DEBUG_BLK_CGROUP
524 idling = blkio_blkg_idling(stats);
525 waiting = blkio_blkg_waiting(stats);
526 empty = blkio_blkg_empty(stats);
527#endif
cdc1184c 528 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
812df48d
DS		 529 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
530 memset(stats, 0, sizeof(struct blkio_group_stats));
cdc1184c 531 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
812df48d
DS		 532 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
533#ifdef CONFIG_DEBUG_BLK_CGROUP
534 if (idling) {
535 blkio_mark_blkg_idling(stats);
536 stats->start_idle_time = now;
537 }
538 if (waiting) {
539 blkio_mark_blkg_waiting(stats);
540 stats->start_group_wait_time = now;
541 }
542 if (empty) {
543 blkio_mark_blkg_empty(stats);
544 stats->start_empty_time = now;
545 }
546#endif
303a3acb
DS		 547 spin_unlock(&blkg->stats_lock);
548 }
549 spin_unlock_irq(&blkcg->lock);
550 return 0;
551}
552
84c124da
DS		 553static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
554 int chars_left, bool diskname_only)
303a3acb 555{
84c124da 556 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
303a3acb
DS		 557 chars_left -= strlen(str);
558 if (chars_left <= 0) {
559 printk(KERN_WARNING
560 "Possibly incorrect cgroup stat display format");
561 return;
562 }
84c124da
DS		 563 if (diskname_only)
564 return;
303a3acb 565 switch (type) {
84c124da 566 case BLKIO_STAT_READ:
303a3acb
DS		 567 strlcat(str, " Read", chars_left);
568 break;
84c124da 569 case BLKIO_STAT_WRITE:
303a3acb
DS		 570 strlcat(str, " Write", chars_left);
571 break;
84c124da 572 case BLKIO_STAT_SYNC:
303a3acb
DS		 573 strlcat(str, " Sync", chars_left);
574 break;
84c124da 575 case BLKIO_STAT_ASYNC:
303a3acb
DS		 576 strlcat(str, " Async", chars_left);
577 break;
84c124da 578 case BLKIO_STAT_TOTAL:
303a3acb
DS		 579 strlcat(str, " Total", chars_left);
580 break;
581 default:
582 strlcat(str, " Invalid", chars_left);
583 }
584}
585
84c124da
DS		 586static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
587 struct cgroup_map_cb *cb, dev_t dev)
588{
589 blkio_get_key_name(0, dev, str, chars_left, true);
590 cb->fill(cb, str, val);
591 return val;
592}
303a3acb 593
84c124da
DS		 594/* This should be called with blkg->stats_lock held */
595static uint64_t blkio_get_stat(struct blkio_group *blkg,
596 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
303a3acb
DS		 597{
598 uint64_t disk_total;
599 char key_str[MAX_KEY_LEN];
84c124da
DS		 600 enum stat_sub_type sub_type;
601
602 if (type == BLKIO_STAT_TIME)
603 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
604 blkg->stats.time, cb, dev);
605 if (type == BLKIO_STAT_SECTORS)
606 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
607 blkg->stats.sectors, cb, dev);
9026e521 608#ifdef CONFIG_DEBUG_BLK_CGROUP
167400d3
JT		 609 if (type == BLKIO_STAT_UNACCOUNTED_TIME)
610 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
611 blkg->stats.unaccounted_time, cb, dev);
cdc1184c
DS		 612 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
613 uint64_t sum = blkg->stats.avg_queue_size_sum;
614 uint64_t samples = blkg->stats.avg_queue_size_samples;
615 if (samples)
616 do_div(sum, samples);
617 else
618 sum = 0;
619 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
620 }
812df48d
DS		 621 if (type == BLKIO_STAT_GROUP_WAIT_TIME)
622 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
623 blkg->stats.group_wait_time, cb, dev);
624 if (type == BLKIO_STAT_IDLE_TIME)
625 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
626 blkg->stats.idle_time, cb, dev);
627 if (type == BLKIO_STAT_EMPTY_TIME)
628 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
629 blkg->stats.empty_time, cb, dev);
84c124da
DS		 630 if (type == BLKIO_STAT_DEQUEUE)
631 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
632 blkg->stats.dequeue, cb, dev);
633#endif
303a3acb 634
84c124da
DS		 635 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
636 sub_type++) {
637 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
638 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
303a3acb 639 }
84c124da
DS		 640 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
641 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
642 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
303a3acb
DS		 643 cb->fill(cb, key_str, disk_total);
644 return disk_total;
645}
646
34d0f179
GJ		 647static int blkio_check_dev_num(dev_t dev)
648{
649 int part = 0;
650 struct gendisk *disk;
651
652 disk = get_gendisk(dev, &part);
653 if (!disk || part)
654 return -ENODEV;
655
656 return 0;
657}
658
659static int blkio_policy_parse_and_set(char *buf,
062a644d 660 struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
34d0f179
GJ		 661{
662 char *s[4], *p, *major_s = NULL, *minor_s = NULL;
663 int ret;
664 unsigned long major, minor, temp;
665 int i = 0;
666 dev_t dev;
9355aede 667 u64 bps, iops;
34d0f179
GJ		 668
669 memset(s, 0, sizeof(s));
670
671 while ((p = strsep(&buf, " ")) != NULL) {
672 if (!*p)
673 continue;
674
675 s[i++] = p;
676
677 /* Prevent from inputing too many things */
678 if (i == 3)
679 break;
680 }
681
682 if (i != 2)
683 return -EINVAL;
684
685 p = strsep(&s[0], ":");
686 if (p != NULL)
687 major_s = p;
688 else
689 return -EINVAL;
690
691 minor_s = s[0];
692 if (!minor_s)
693 return -EINVAL;
694
695 ret = strict_strtoul(major_s, 10, &major);
696 if (ret)
697 return -EINVAL;
698
699 ret = strict_strtoul(minor_s, 10, &minor);
700 if (ret)
701 return -EINVAL;
702
703 dev = MKDEV(major, minor);
704
705 ret = blkio_check_dev_num(dev);
706 if (ret)
707 return ret;
708
709 newpn->dev = dev;
710
711 if (s[1] == NULL)
712 return -EINVAL;
713
062a644d
VG		 714 switch (plid) {
715 case BLKIO_POLICY_PROP:
716 ret = strict_strtoul(s[1], 10, &temp);
717 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
718 temp > BLKIO_WEIGHT_MAX)
719 return -EINVAL;
34d0f179 720
062a644d
VG		 721 newpn->plid = plid;
722 newpn->fileid = fileid;
4c9eefa1
VG		 723 newpn->val.weight = temp;
724 break;
725 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 726 switch(fileid) {
727 case BLKIO_THROTL_read_bps_device:
728 case BLKIO_THROTL_write_bps_device:
729 ret = strict_strtoull(s[1], 10, &bps);
730 if (ret)
731 return -EINVAL;
4c9eefa1 732
7702e8f4
VG		 733 newpn->plid = plid;
734 newpn->fileid = fileid;
735 newpn->val.bps = bps;
736 break;
737 case BLKIO_THROTL_read_iops_device:
738 case BLKIO_THROTL_write_iops_device:
9355aede 739 ret = strict_strtoull(s[1], 10, &iops);
7702e8f4
VG		 740 if (ret)
741 return -EINVAL;
742
9355aede
VG		 743 if (iops > THROTL_IOPS_MAX)
744 return -EINVAL;
745
7702e8f4
VG		 746 newpn->plid = plid;
747 newpn->fileid = fileid;
9355aede 748 newpn->val.iops = (unsigned int)iops;
7702e8f4
VG		 749 break;
750 }
062a644d
VG		 751 break;
752 default:
753 BUG();
754 }
34d0f179
GJ		 755
756 return 0;
757}
758
759unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
760 dev_t dev)
761{
762 struct blkio_policy_node *pn;
763
062a644d
VG		 764 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
765 BLKIO_PROP_weight_device);
34d0f179 766 if (pn)
4c9eefa1 767 return pn->val.weight;
34d0f179
GJ		 768 else
769 return blkcg->weight;
770}
771EXPORT_SYMBOL_GPL(blkcg_get_weight);
772
4c9eefa1
VG		 773uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
774{
775 struct blkio_policy_node *pn;
776
777 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
778 BLKIO_THROTL_read_bps_device);
779 if (pn)
780 return pn->val.bps;
781 else
782 return -1;
783}
784
785uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
786{
787 struct blkio_policy_node *pn;
788 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
789 BLKIO_THROTL_write_bps_device);
790 if (pn)
791 return pn->val.bps;
792 else
793 return -1;
794}
795
7702e8f4
VG		 796unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
797{
798 struct blkio_policy_node *pn;
799
800 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
801 BLKIO_THROTL_read_iops_device);
802 if (pn)
803 return pn->val.iops;
804 else
805 return -1;
806}
807
808unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
809{
810 struct blkio_policy_node *pn;
811 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
812 BLKIO_THROTL_write_iops_device);
813 if (pn)
814 return pn->val.iops;
815 else
816 return -1;
817}
818
062a644d
VG		 819/* Checks whether user asked for deleting a policy rule */
820static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
821{
822 switch(pn->plid) {
823 case BLKIO_POLICY_PROP:
4c9eefa1
VG		 824 if (pn->val.weight == 0)
825 return 1;
826 break;
827 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 828 switch(pn->fileid) {
829 case BLKIO_THROTL_read_bps_device:
830 case BLKIO_THROTL_write_bps_device:
831 if (pn->val.bps == 0)
832 return 1;
833 break;
834 case BLKIO_THROTL_read_iops_device:
835 case BLKIO_THROTL_write_iops_device:
836 if (pn->val.iops == 0)
837 return 1;
838 }
062a644d
VG		 839 break;
840 default:
841 BUG();
842 }
843
844 return 0;
845}
846
847static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
848 struct blkio_policy_node *newpn)
849{
850 switch(oldpn->plid) {
851 case BLKIO_POLICY_PROP:
4c9eefa1
VG		 852 oldpn->val.weight = newpn->val.weight;
853 break;
854 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 855 switch(newpn->fileid) {
856 case BLKIO_THROTL_read_bps_device:
857 case BLKIO_THROTL_write_bps_device:
858 oldpn->val.bps = newpn->val.bps;
859 break;
860 case BLKIO_THROTL_read_iops_device:
861 case BLKIO_THROTL_write_iops_device:
862 oldpn->val.iops = newpn->val.iops;
863 }
062a644d
VG		 864 break;
865 default:
866 BUG();
867 }
868}
869
870/*
25985edc 871 * Some rules/values in blkg have changed. Propagate those to respective
062a644d
VG		 872 * policies.
873 */
874static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
875 struct blkio_group *blkg, struct blkio_policy_node *pn)
876{
7702e8f4 877 unsigned int weight, iops;
4c9eefa1 878 u64 bps;
062a644d
VG		 879
880 switch(pn->plid) {
881 case BLKIO_POLICY_PROP:
4c9eefa1 882 weight = pn->val.weight ? pn->val.weight :
062a644d
VG		 883 blkcg->weight;
884 blkio_update_group_weight(blkg, weight);
885 break;
4c9eefa1
VG		 886 case BLKIO_POLICY_THROTL:
887 switch(pn->fileid) {
888 case BLKIO_THROTL_read_bps_device:
889 case BLKIO_THROTL_write_bps_device:
890 bps = pn->val.bps ? pn->val.bps : (-1);
891 blkio_update_group_bps(blkg, bps, pn->fileid);
892 break;
7702e8f4
VG		 893 case BLKIO_THROTL_read_iops_device:
894 case BLKIO_THROTL_write_iops_device:
895 iops = pn->val.iops ? pn->val.iops : (-1);
896 blkio_update_group_iops(blkg, iops, pn->fileid);
897 break;
4c9eefa1
VG		 898 }
899 break;
062a644d
VG		 900 default:
901 BUG();
902 }
903}
904
905/*
25985edc 906 * A policy node rule has been updated. Propagate this update to all the
062a644d
VG		 907 * block groups which might be affected by this update.
908 */
909static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
910 struct blkio_policy_node *pn)
911{
912 struct blkio_group *blkg;
913 struct hlist_node *n;
914
915 spin_lock(&blkio_list_lock);
916 spin_lock_irq(&blkcg->lock);
34d0f179 917
062a644d
VG		 918 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
919 if (pn->dev != blkg->dev || pn->plid != blkg->plid)
920 continue;
921 blkio_update_blkg_policy(blkcg, blkg, pn);
922 }
923
924 spin_unlock_irq(&blkcg->lock);
925 spin_unlock(&blkio_list_lock);
926}
34d0f179 927
062a644d
VG		 928static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
929 const char *buffer)
34d0f179
GJ		 930{
931 int ret = 0;
932 char *buf;
933 struct blkio_policy_node *newpn, *pn;
934 struct blkio_cgroup *blkcg;
34d0f179 935 int keep_newpn = 0;
062a644d
VG		 936 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
937 int fileid = BLKIOFILE_ATTR(cft->private);
34d0f179
GJ		 938
939 buf = kstrdup(buffer, GFP_KERNEL);
940 if (!buf)
941 return -ENOMEM;
942
943 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
944 if (!newpn) {
945 ret = -ENOMEM;
946 goto free_buf;
947 }
948
062a644d 949 ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
34d0f179
GJ		 950 if (ret)
951 goto free_newpn;
952
953 blkcg = cgroup_to_blkio_cgroup(cgrp);
954
955 spin_lock_irq(&blkcg->lock);
956
062a644d 957 pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
34d0f179 958 if (!pn) {
062a644d 959 if (!blkio_delete_rule_command(newpn)) {
34d0f179
GJ		 960 blkio_policy_insert_node(blkcg, newpn);
961 keep_newpn = 1;
962 }
963 spin_unlock_irq(&blkcg->lock);
964 goto update_io_group;
965 }
966
062a644d 967 if (blkio_delete_rule_command(newpn)) {
34d0f179
GJ		 968 blkio_policy_delete_node(pn);
969 spin_unlock_irq(&blkcg->lock);
970 goto update_io_group;
971 }
972 spin_unlock_irq(&blkcg->lock);
973
062a644d 974 blkio_update_policy_rule(pn, newpn);
34d0f179
GJ		 975
976update_io_group:
062a644d 977 blkio_update_policy_node_blkg(blkcg, newpn);
34d0f179
GJ		 978
979free_newpn:
980 if (!keep_newpn)
981 kfree(newpn);
982free_buf:
983 kfree(buf);
984 return ret;
985}
986
062a644d
VG		 987static void
988blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
34d0f179 989{
062a644d
VG		 990 switch(pn->plid) {
991 case BLKIO_POLICY_PROP:
992 if (pn->fileid == BLKIO_PROP_weight_device)
993 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
4c9eefa1
VG		 994 MINOR(pn->dev), pn->val.weight);
995 break;
996 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 997 switch(pn->fileid) {
998 case BLKIO_THROTL_read_bps_device:
999 case BLKIO_THROTL_write_bps_device:
4c9eefa1
VG		 1000 seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
1001 MINOR(pn->dev), pn->val.bps);
7702e8f4
VG		 1002 break;
1003 case BLKIO_THROTL_read_iops_device:
1004 case BLKIO_THROTL_write_iops_device:
1005 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
1006 MINOR(pn->dev), pn->val.iops);
1007 break;
1008 }
062a644d
VG		 1009 break;
1010 default:
1011 BUG();
1012 }
1013}
34d0f179 1014
062a644d
VG		 1015/* cgroup files which read their data from policy nodes end up here */
1016static void blkio_read_policy_node_files(struct cftype *cft,
1017 struct blkio_cgroup *blkcg, struct seq_file *m)
34d0f179 1018{
34d0f179 1019 struct blkio_policy_node *pn;
34d0f179 1020
0f3942a3
JA		 1021 if (!list_empty(&blkcg->policy_list)) {
1022 spin_lock_irq(&blkcg->lock);
1023 list_for_each_entry(pn, &blkcg->policy_list, node) {
062a644d
VG		 1024 if (!pn_matches_cftype(cft, pn))
1025 continue;
1026 blkio_print_policy_node(m, pn);
0f3942a3
JA		 1027 }
1028 spin_unlock_irq(&blkcg->lock);
34d0f179 1029 }
062a644d
VG		 1030}
1031
1032static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
1033 struct seq_file *m)
1034{
1035 struct blkio_cgroup *blkcg;
1036 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1037 int name = BLKIOFILE_ATTR(cft->private);
1038
1039 blkcg = cgroup_to_blkio_cgroup(cgrp);
1040
1041 switch(plid) {
1042 case BLKIO_POLICY_PROP:
1043 switch(name) {
1044 case BLKIO_PROP_weight_device:
1045 blkio_read_policy_node_files(cft, blkcg, m);
1046 return 0;
1047 default:
1048 BUG();
1049 }
1050 break;
4c9eefa1
VG		 1051 case BLKIO_POLICY_THROTL:
1052 switch(name){
1053 case BLKIO_THROTL_read_bps_device:
1054 case BLKIO_THROTL_write_bps_device:
7702e8f4
VG		 1055 case BLKIO_THROTL_read_iops_device:
1056 case BLKIO_THROTL_write_iops_device:
4c9eefa1
VG		 1057 blkio_read_policy_node_files(cft, blkcg, m);
1058 return 0;
1059 default:
1060 BUG();
1061 }
1062 break;
062a644d
VG		 1063 default:
1064 BUG();
1065 }
1066
1067 return 0;
1068}
1069
1070static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
1071 struct cftype *cft, struct cgroup_map_cb *cb, enum stat_type type,
1072 bool show_total)
1073{
1074 struct blkio_group *blkg;
1075 struct hlist_node *n;
1076 uint64_t cgroup_total = 0;
1077
1078 rcu_read_lock();
1079 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
1080 if (blkg->dev) {
1081 if (!cftype_blkg_same_policy(cft, blkg))
1082 continue;
1083 spin_lock_irq(&blkg->stats_lock);
1084 cgroup_total += blkio_get_stat(blkg, cb, blkg->dev,
1085 type);
1086 spin_unlock_irq(&blkg->stats_lock);
1087 }
1088 }
1089 if (show_total)
1090 cb->fill(cb, "Total", cgroup_total);
1091 rcu_read_unlock();
1092 return 0;
1093}
1094
1095/* All map kind of cgroup file get serviced by this function */
1096static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
1097 struct cgroup_map_cb *cb)
1098{
1099 struct blkio_cgroup *blkcg;
1100 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1101 int name = BLKIOFILE_ATTR(cft->private);
1102
1103 blkcg = cgroup_to_blkio_cgroup(cgrp);
1104
1105 switch(plid) {
1106 case BLKIO_POLICY_PROP:
1107 switch(name) {
1108 case BLKIO_PROP_time:
1109 return blkio_read_blkg_stats(blkcg, cft, cb,
1110 BLKIO_STAT_TIME, 0);
1111 case BLKIO_PROP_sectors:
1112 return blkio_read_blkg_stats(blkcg, cft, cb,
1113 BLKIO_STAT_SECTORS, 0);
1114 case BLKIO_PROP_io_service_bytes:
1115 return blkio_read_blkg_stats(blkcg, cft, cb,
1116 BLKIO_STAT_SERVICE_BYTES, 1);
1117 case BLKIO_PROP_io_serviced:
1118 return blkio_read_blkg_stats(blkcg, cft, cb,
1119 BLKIO_STAT_SERVICED, 1);
1120 case BLKIO_PROP_io_service_time:
1121 return blkio_read_blkg_stats(blkcg, cft, cb,
1122 BLKIO_STAT_SERVICE_TIME, 1);
1123 case BLKIO_PROP_io_wait_time:
1124 return blkio_read_blkg_stats(blkcg, cft, cb,
1125 BLKIO_STAT_WAIT_TIME, 1);
1126 case BLKIO_PROP_io_merged:
1127 return blkio_read_blkg_stats(blkcg, cft, cb,
1128 BLKIO_STAT_MERGED, 1);
1129 case BLKIO_PROP_io_queued:
1130 return blkio_read_blkg_stats(blkcg, cft, cb,
1131 BLKIO_STAT_QUEUED, 1);
1132#ifdef CONFIG_DEBUG_BLK_CGROUP
9026e521
JT		 1133 case BLKIO_PROP_unaccounted_time:
1134 return blkio_read_blkg_stats(blkcg, cft, cb,
1135 BLKIO_STAT_UNACCOUNTED_TIME, 0);
062a644d
VG		 1136 case BLKIO_PROP_dequeue:
1137 return blkio_read_blkg_stats(blkcg, cft, cb,
1138 BLKIO_STAT_DEQUEUE, 0);
1139 case BLKIO_PROP_avg_queue_size:
1140 return blkio_read_blkg_stats(blkcg, cft, cb,
1141 BLKIO_STAT_AVG_QUEUE_SIZE, 0);
1142 case BLKIO_PROP_group_wait_time:
1143 return blkio_read_blkg_stats(blkcg, cft, cb,
1144 BLKIO_STAT_GROUP_WAIT_TIME, 0);
1145 case BLKIO_PROP_idle_time:
1146 return blkio_read_blkg_stats(blkcg, cft, cb,
1147 BLKIO_STAT_IDLE_TIME, 0);
1148 case BLKIO_PROP_empty_time:
1149 return blkio_read_blkg_stats(blkcg, cft, cb,
1150 BLKIO_STAT_EMPTY_TIME, 0);
1151#endif
1152 default:
1153 BUG();
1154 }
1155 break;
4c9eefa1
VG		 1156 case BLKIO_POLICY_THROTL:
1157 switch(name){
1158 case BLKIO_THROTL_io_service_bytes:
1159 return blkio_read_blkg_stats(blkcg, cft, cb,
1160 BLKIO_STAT_SERVICE_BYTES, 1);
1161 case BLKIO_THROTL_io_serviced:
1162 return blkio_read_blkg_stats(blkcg, cft, cb,
1163 BLKIO_STAT_SERVICED, 1);
1164 default:
1165 BUG();
1166 }
1167 break;
062a644d
VG		 1168 default:
1169 BUG();
1170 }
1171
1172 return 0;
1173}
1174
1175static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
1176{
1177 struct blkio_group *blkg;
1178 struct hlist_node *n;
1179 struct blkio_policy_node *pn;
1180
1181 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
1182 return -EINVAL;
1183
1184 spin_lock(&blkio_list_lock);
1185 spin_lock_irq(&blkcg->lock);
1186 blkcg->weight = (unsigned int)val;
1187
1188 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
1189 pn = blkio_policy_search_node(blkcg, blkg->dev,
1190 BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
1191 if (pn)
1192 continue;
1193
1194 blkio_update_group_weight(blkg, blkcg->weight);
1195 }
1196 spin_unlock_irq(&blkcg->lock);
1197 spin_unlock(&blkio_list_lock);
1198 return 0;
1199}
1200
1201static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
1202 struct blkio_cgroup *blkcg;
1203 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1204 int name = BLKIOFILE_ATTR(cft->private);
1205
1206 blkcg = cgroup_to_blkio_cgroup(cgrp);
1207
1208 switch(plid) {
1209 case BLKIO_POLICY_PROP:
1210 switch(name) {
1211 case BLKIO_PROP_weight:
1212 return (u64)blkcg->weight;
1213 }
1214 break;
1215 default:
1216 BUG();
1217 }
1218 return 0;
1219}
1220
1221static int
1222blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
1223{
1224 struct blkio_cgroup *blkcg;
1225 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1226 int name = BLKIOFILE_ATTR(cft->private);
1227
1228 blkcg = cgroup_to_blkio_cgroup(cgrp);
1229
1230 switch(plid) {
1231 case BLKIO_POLICY_PROP:
1232 switch(name) {
1233 case BLKIO_PROP_weight:
1234 return blkio_weight_write(blkcg, val);
1235 }
1236 break;
1237 default:
1238 BUG();
1239 }
34d0f179 1240
34d0f179
GJ		 1241 return 0;
1242}
1243
31e4c28d 1244struct cftype blkio_files[] = {
34d0f179
GJ		 1245 {
1246 .name = "weight_device",
062a644d
VG		 1247 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1248 BLKIO_PROP_weight_device),
1249 .read_seq_string = blkiocg_file_read,
1250 .write_string = blkiocg_file_write,
34d0f179
GJ		 1251 .max_write_len = 256,
1252 },
31e4c28d
VG		 1253 {
1254 .name = "weight",
062a644d
VG		 1255 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1256 BLKIO_PROP_weight),
1257 .read_u64 = blkiocg_file_read_u64,
1258 .write_u64 = blkiocg_file_write_u64,
31e4c28d 1259 },
22084190
VG		 1260 {
1261 .name = "time",
062a644d
VG		 1262 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1263 BLKIO_PROP_time),
1264 .read_map = blkiocg_file_read_map,
22084190
VG		 1265 },
1266 {
1267 .name = "sectors",
062a644d
VG		 1268 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1269 BLKIO_PROP_sectors),
1270 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1271 },
1272 {
1273 .name = "io_service_bytes",
062a644d
VG		 1274 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1275 BLKIO_PROP_io_service_bytes),
1276 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1277 },
1278 {
1279 .name = "io_serviced",
062a644d
VG		 1280 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1281 BLKIO_PROP_io_serviced),
1282 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1283 },
1284 {
1285 .name = "io_service_time",
062a644d
VG		 1286 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1287 BLKIO_PROP_io_service_time),
1288 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1289 },
1290 {
1291 .name = "io_wait_time",
062a644d
VG		 1292 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1293 BLKIO_PROP_io_wait_time),
1294 .read_map = blkiocg_file_read_map,
84c124da 1295 },
812d4026
DS		 1296 {
1297 .name = "io_merged",
062a644d
VG		 1298 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1299 BLKIO_PROP_io_merged),
1300 .read_map = blkiocg_file_read_map,
812d4026 1301 },
cdc1184c
DS		 1302 {
1303 .name = "io_queued",
062a644d
VG		 1304 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1305 BLKIO_PROP_io_queued),
1306 .read_map = blkiocg_file_read_map,
cdc1184c 1307 },
84c124da
DS		 1308 {
1309 .name = "reset_stats",
1310 .write_u64 = blkiocg_reset_stats,
22084190 1311 },
13f98250
VG		 1312#ifdef CONFIG_BLK_DEV_THROTTLING
1313 {
1314 .name = "throttle.read_bps_device",
1315 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1316 BLKIO_THROTL_read_bps_device),
1317 .read_seq_string = blkiocg_file_read,
1318 .write_string = blkiocg_file_write,
1319 .max_write_len = 256,
1320 },
1321
1322 {
1323 .name = "throttle.write_bps_device",
1324 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1325 BLKIO_THROTL_write_bps_device),
1326 .read_seq_string = blkiocg_file_read,
1327 .write_string = blkiocg_file_write,
1328 .max_write_len = 256,
1329 },
1330
1331 {
1332 .name = "throttle.read_iops_device",
1333 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1334 BLKIO_THROTL_read_iops_device),
1335 .read_seq_string = blkiocg_file_read,
1336 .write_string = blkiocg_file_write,
1337 .max_write_len = 256,
1338 },
1339
1340 {
1341 .name = "throttle.write_iops_device",
1342 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1343 BLKIO_THROTL_write_iops_device),
1344 .read_seq_string = blkiocg_file_read,
1345 .write_string = blkiocg_file_write,
1346 .max_write_len = 256,
1347 },
1348 {
1349 .name = "throttle.io_service_bytes",
1350 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1351 BLKIO_THROTL_io_service_bytes),
1352 .read_map = blkiocg_file_read_map,
1353 },
1354 {
1355 .name = "throttle.io_serviced",
1356 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1357 BLKIO_THROTL_io_serviced),
1358 .read_map = blkiocg_file_read_map,
1359 },
1360#endif /* CONFIG_BLK_DEV_THROTTLING */
1361
22084190 1362#ifdef CONFIG_DEBUG_BLK_CGROUP
cdc1184c
DS		 1363 {
1364 .name = "avg_queue_size",
062a644d
VG		 1365 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1366 BLKIO_PROP_avg_queue_size),
1367 .read_map = blkiocg_file_read_map,
cdc1184c 1368 },
812df48d
DS		 1369 {
1370 .name = "group_wait_time",
062a644d
VG		 1371 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1372 BLKIO_PROP_group_wait_time),
1373 .read_map = blkiocg_file_read_map,
812df48d
DS		 1374 },
1375 {
1376 .name = "idle_time",
062a644d
VG		 1377 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1378 BLKIO_PROP_idle_time),
1379 .read_map = blkiocg_file_read_map,
812df48d
DS		 1380 },
1381 {
1382 .name = "empty_time",
062a644d
VG		 1383 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1384 BLKIO_PROP_empty_time),
1385 .read_map = blkiocg_file_read_map,
812df48d 1386 },
cdc1184c 1387 {
22084190 1388 .name = "dequeue",
062a644d
VG		 1389 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1390 BLKIO_PROP_dequeue),
1391 .read_map = blkiocg_file_read_map,
cdc1184c 1392 },
9026e521
JT		 1393 {
1394 .name = "unaccounted_time",
1395 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1396 BLKIO_PROP_unaccounted_time),
1397 .read_map = blkiocg_file_read_map,
1398 },
22084190 1399#endif
31e4c28d
VG		 1400};
1401
1402static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1403{
1404 return cgroup_add_files(cgroup, subsys, blkio_files,
1405 ARRAY_SIZE(blkio_files));
1406}
1407
1408static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1409{
1410 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
b1c35769
VG		 1411 unsigned long flags;
1412 struct blkio_group *blkg;
1413 void *key;
3e252066 1414 struct blkio_policy_type *blkiop;
34d0f179 1415 struct blkio_policy_node *pn, *pntmp;
b1c35769
VG		 1416
1417 rcu_read_lock();
0f3942a3
JA		 1418 do {
1419 spin_lock_irqsave(&blkcg->lock, flags);
b1c35769 1420
0f3942a3
JA		 1421 if (hlist_empty(&blkcg->blkg_list)) {
1422 spin_unlock_irqrestore(&blkcg->lock, flags);
1423 break;
1424 }
b1c35769 1425
0f3942a3
JA		 1426 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
1427 blkcg_node);
1428 key = rcu_dereference(blkg->key);
1429 __blkiocg_del_blkio_group(blkg);
31e4c28d 1430
0f3942a3 1431 spin_unlock_irqrestore(&blkcg->lock, flags);
b1c35769 1432
0f3942a3
JA		 1433 /*
1434 * This blkio_group is being unlinked as associated cgroup is
1435 * going away. Let all the IO controlling policies know about
61014e96 1436 * this event.
0f3942a3
JA		 1437 */
1438 spin_lock(&blkio_list_lock);
61014e96
VG		 1439 list_for_each_entry(blkiop, &blkio_list, list) {
1440 if (blkiop->plid != blkg->plid)
1441 continue;
0f3942a3 1442 blkiop->ops.blkio_unlink_group_fn(key, blkg);
61014e96 1443 }
0f3942a3
JA		 1444 spin_unlock(&blkio_list_lock);
1445 } while (1);
34d0f179 1446
34d0f179
GJ		 1447 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
1448 blkio_policy_delete_node(pn);
1449 kfree(pn);
1450 }
0f3942a3 1451
31e4c28d 1452 free_css_id(&blkio_subsys, &blkcg->css);
b1c35769 1453 rcu_read_unlock();
67523c48
BB		 1454 if (blkcg != &blkio_root_cgroup)
1455 kfree(blkcg);
31e4c28d
VG		 1456}
1457
1458static struct cgroup_subsys_state *
1459blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1460{
0341509f
LZ		 1461 struct blkio_cgroup *blkcg;
1462 struct cgroup *parent = cgroup->parent;
31e4c28d 1463
0341509f 1464 if (!parent) {
31e4c28d
VG		 1465 blkcg = &blkio_root_cgroup;
1466 goto done;
1467 }
1468
31e4c28d
VG		 1469 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
1470 if (!blkcg)
1471 return ERR_PTR(-ENOMEM);
1472
1473 blkcg->weight = BLKIO_WEIGHT_DEFAULT;
1474done:
1475 spin_lock_init(&blkcg->lock);
1476 INIT_HLIST_HEAD(&blkcg->blkg_list);
1477
34d0f179 1478 INIT_LIST_HEAD(&blkcg->policy_list);
31e4c28d
VG		 1479 return &blkcg->css;
1480}
1481
1482/*
1483 * We cannot support shared io contexts, as we have no mean to support
1484 * two tasks with the same ioc in two different groups without major rework
1485 * of the main cic data structures. For now we allow a task to change
1486 * its cgroup only if it's the only owner of its ioc.
1487 */
1488static int blkiocg_can_attach(struct cgroup_subsys *subsys,
1489 struct cgroup *cgroup, struct task_struct *tsk,
1490 bool threadgroup)
1491{
1492 struct io_context *ioc;
1493 int ret = 0;
1494
1495 /* task_lock() is needed to avoid races with exit_io_context() */
1496 task_lock(tsk);
1497 ioc = tsk->io_context;
1498 if (ioc && atomic_read(&ioc->nr_tasks) > 1)
1499 ret = -EINVAL;
1500 task_unlock(tsk);
1501
1502 return ret;
1503}
1504
1505static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup,
1506 struct cgroup *prev, struct task_struct *tsk,
1507 bool threadgroup)
1508{
1509 struct io_context *ioc;
1510
1511 task_lock(tsk);
1512 ioc = tsk->io_context;
1513 if (ioc)
1514 ioc->cgroup_changed = 1;
1515 task_unlock(tsk);
1516}
1517
3e252066
VG		 1518void blkio_policy_register(struct blkio_policy_type *blkiop)
1519{
1520 spin_lock(&blkio_list_lock);
1521 list_add_tail(&blkiop->list, &blkio_list);
1522 spin_unlock(&blkio_list_lock);
1523}
1524EXPORT_SYMBOL_GPL(blkio_policy_register);
1525
1526void blkio_policy_unregister(struct blkio_policy_type *blkiop)
1527{
1528 spin_lock(&blkio_list_lock);
1529 list_del_init(&blkiop->list);
1530 spin_unlock(&blkio_list_lock);
1531}
1532EXPORT_SYMBOL_GPL(blkio_policy_unregister);
67523c48
BB		 1533
1534static int __init init_cgroup_blkio(void)
1535{
1536 return cgroup_load_subsys(&blkio_subsys);
1537}
1538
1539static void __exit exit_cgroup_blkio(void)
1540{
1541 cgroup_unload_subsys(&blkio_subsys);
1542}
1543
1544module_init(init_cgroup_blkio);
1545module_exit(exit_cgroup_blkio);
1546MODULE_LICENSE("GPL");
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