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blkio-throttle: There is no need to convert jiffies to milli seconds
[net-next-2.6.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
303a3acb 374void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
22084190 375{
303a3acb
DS		 376 unsigned long flags;
377
378 spin_lock_irqsave(&blkg->stats_lock, flags);
379 blkg->stats.time += time;
380 spin_unlock_irqrestore(&blkg->stats_lock, flags);
22084190 381}
303a3acb 382EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
22084190 383
84c124da
DS		 384void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
385 uint64_t bytes, bool direction, bool sync)
9195291e
DS		 386{
387 struct blkio_group_stats *stats;
388 unsigned long flags;
389
390 spin_lock_irqsave(&blkg->stats_lock, flags);
391 stats = &blkg->stats;
84c124da
DS		 392 stats->sectors += bytes >> 9;
393 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
394 sync);
395 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
396 direction, sync);
9195291e
DS		 397 spin_unlock_irqrestore(&blkg->stats_lock, flags);
398}
84c124da 399EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
9195291e 400
84c124da
DS		 401void blkiocg_update_completion_stats(struct blkio_group *blkg,
402 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
9195291e
DS		 403{
404 struct blkio_group_stats *stats;
405 unsigned long flags;
406 unsigned long long now = sched_clock();
407
408 spin_lock_irqsave(&blkg->stats_lock, flags);
409 stats = &blkg->stats;
84c124da
DS		 410 if (time_after64(now, io_start_time))
411 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
412 now - io_start_time, direction, sync);
413 if (time_after64(io_start_time, start_time))
414 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
415 io_start_time - start_time, direction, sync);
9195291e
DS		 416 spin_unlock_irqrestore(&blkg->stats_lock, flags);
417}
84c124da 418EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
9195291e 419
812d4026
DS		 420void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
421 bool sync)
422{
423 unsigned long flags;
424
425 spin_lock_irqsave(&blkg->stats_lock, flags);
426 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,
427 sync);
428 spin_unlock_irqrestore(&blkg->stats_lock, flags);
429}
430EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
431
31e4c28d 432void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
062a644d
VG		 433 struct blkio_group *blkg, void *key, dev_t dev,
434 enum blkio_policy_id plid)
31e4c28d
VG		 435{
436 unsigned long flags;
437
438 spin_lock_irqsave(&blkcg->lock, flags);
8d2a91f8 439 spin_lock_init(&blkg->stats_lock);
31e4c28d 440 rcu_assign_pointer(blkg->key, key);
b1c35769 441 blkg->blkcg_id = css_id(&blkcg->css);
31e4c28d 442 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
062a644d 443 blkg->plid = plid;
31e4c28d 444 spin_unlock_irqrestore(&blkcg->lock, flags);
2868ef7b
VG		 445 /* Need to take css reference ? */
446 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
22084190 447 blkg->dev = dev;
31e4c28d 448}
9d6a986c 449EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
31e4c28d 450
b1c35769
VG		 451static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
452{
453 hlist_del_init_rcu(&blkg->blkcg_node);
454 blkg->blkcg_id = 0;
455}
456
457/*
458 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
459 * indicating that blk_group was unhashed by the time we got to it.
460 */
31e4c28d
VG		 461int blkiocg_del_blkio_group(struct blkio_group *blkg)
462{
b1c35769
VG		 463 struct blkio_cgroup *blkcg;
464 unsigned long flags;
465 struct cgroup_subsys_state *css;
466 int ret = 1;
467
468 rcu_read_lock();
469 css = css_lookup(&blkio_subsys, blkg->blkcg_id);
0f3942a3
JA		 470 if (css) {
471 blkcg = container_of(css, struct blkio_cgroup, css);
472 spin_lock_irqsave(&blkcg->lock, flags);
473 if (!hlist_unhashed(&blkg->blkcg_node)) {
474 __blkiocg_del_blkio_group(blkg);
475 ret = 0;
476 }
477 spin_unlock_irqrestore(&blkcg->lock, flags);
b1c35769 478 }
0f3942a3 479
b1c35769
VG		 480 rcu_read_unlock();
481 return ret;
31e4c28d 482}
9d6a986c 483EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
31e4c28d
VG		 484
485/* called under rcu_read_lock(). */
486struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
487{
488 struct blkio_group *blkg;
489 struct hlist_node *n;
490 void *__key;
491
492 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
493 __key = blkg->key;
494 if (__key == key)
495 return blkg;
496 }
497
498 return NULL;
499}
9d6a986c 500EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
31e4c28d 501
303a3acb 502static int
84c124da 503blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
303a3acb
DS		 504{
505 struct blkio_cgroup *blkcg;
506 struct blkio_group *blkg;
812df48d 507 struct blkio_group_stats *stats;
303a3acb 508 struct hlist_node *n;
cdc1184c
DS		 509 uint64_t queued[BLKIO_STAT_TOTAL];
510 int i;
812df48d
DS		 511#ifdef CONFIG_DEBUG_BLK_CGROUP
512 bool idling, waiting, empty;
513 unsigned long long now = sched_clock();
514#endif
303a3acb
DS		 515
516 blkcg = cgroup_to_blkio_cgroup(cgroup);
517 spin_lock_irq(&blkcg->lock);
518 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
519 spin_lock(&blkg->stats_lock);
812df48d
DS		 520 stats = &blkg->stats;
521#ifdef CONFIG_DEBUG_BLK_CGROUP
522 idling = blkio_blkg_idling(stats);
523 waiting = blkio_blkg_waiting(stats);
524 empty = blkio_blkg_empty(stats);
525#endif
cdc1184c 526 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
812df48d
DS		 527 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
528 memset(stats, 0, sizeof(struct blkio_group_stats));
cdc1184c 529 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
812df48d
DS		 530 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
531#ifdef CONFIG_DEBUG_BLK_CGROUP
532 if (idling) {
533 blkio_mark_blkg_idling(stats);
534 stats->start_idle_time = now;
535 }
536 if (waiting) {
537 blkio_mark_blkg_waiting(stats);
538 stats->start_group_wait_time = now;
539 }
540 if (empty) {
541 blkio_mark_blkg_empty(stats);
542 stats->start_empty_time = now;
543 }
544#endif
303a3acb
DS		 545 spin_unlock(&blkg->stats_lock);
546 }
547 spin_unlock_irq(&blkcg->lock);
548 return 0;
549}
550
84c124da
DS		 551static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
552 int chars_left, bool diskname_only)
303a3acb 553{
84c124da 554 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
303a3acb
DS		 555 chars_left -= strlen(str);
556 if (chars_left <= 0) {
557 printk(KERN_WARNING
558 "Possibly incorrect cgroup stat display format");
559 return;
560 }
84c124da
DS		 561 if (diskname_only)
562 return;
303a3acb 563 switch (type) {
84c124da 564 case BLKIO_STAT_READ:
303a3acb
DS		 565 strlcat(str, " Read", chars_left);
566 break;
84c124da 567 case BLKIO_STAT_WRITE:
303a3acb
DS		 568 strlcat(str, " Write", chars_left);
569 break;
84c124da 570 case BLKIO_STAT_SYNC:
303a3acb
DS		 571 strlcat(str, " Sync", chars_left);
572 break;
84c124da 573 case BLKIO_STAT_ASYNC:
303a3acb
DS		 574 strlcat(str, " Async", chars_left);
575 break;
84c124da 576 case BLKIO_STAT_TOTAL:
303a3acb
DS		 577 strlcat(str, " Total", chars_left);
578 break;
579 default:
580 strlcat(str, " Invalid", chars_left);
581 }
582}
583
84c124da
DS		 584static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
585 struct cgroup_map_cb *cb, dev_t dev)
586{
587 blkio_get_key_name(0, dev, str, chars_left, true);
588 cb->fill(cb, str, val);
589 return val;
590}
303a3acb 591
84c124da
DS		 592/* This should be called with blkg->stats_lock held */
593static uint64_t blkio_get_stat(struct blkio_group *blkg,
594 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
303a3acb
DS		 595{
596 uint64_t disk_total;
597 char key_str[MAX_KEY_LEN];
84c124da
DS		 598 enum stat_sub_type sub_type;
599
600 if (type == BLKIO_STAT_TIME)
601 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
602 blkg->stats.time, cb, dev);
603 if (type == BLKIO_STAT_SECTORS)
604 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
605 blkg->stats.sectors, cb, dev);
606#ifdef CONFIG_DEBUG_BLK_CGROUP
cdc1184c
DS		 607 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
608 uint64_t sum = blkg->stats.avg_queue_size_sum;
609 uint64_t samples = blkg->stats.avg_queue_size_samples;
610 if (samples)
611 do_div(sum, samples);
612 else
613 sum = 0;
614 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
615 }
812df48d
DS		 616 if (type == BLKIO_STAT_GROUP_WAIT_TIME)
617 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
618 blkg->stats.group_wait_time, cb, dev);
619 if (type == BLKIO_STAT_IDLE_TIME)
620 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
621 blkg->stats.idle_time, cb, dev);
622 if (type == BLKIO_STAT_EMPTY_TIME)
623 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
624 blkg->stats.empty_time, cb, dev);
84c124da
DS		 625 if (type == BLKIO_STAT_DEQUEUE)
626 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
627 blkg->stats.dequeue, cb, dev);
628#endif
303a3acb 629
84c124da
DS		 630 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
631 sub_type++) {
632 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
633 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
303a3acb 634 }
84c124da
DS		 635 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
636 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
637 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
303a3acb
DS		 638 cb->fill(cb, key_str, disk_total);
639 return disk_total;
640}
641
34d0f179
GJ		 642static 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
654static int blkio_policy_parse_and_set(char *buf,
062a644d 655 struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
34d0f179
GJ		 656{
657 char *s[4], *p, *major_s = NULL, *minor_s = NULL;
658 int ret;
7702e8f4 659 unsigned long major, minor, temp, iops;
34d0f179
GJ		 660 int i = 0;
661 dev_t dev;
4c9eefa1 662 u64 bps;
34d0f179
GJ		 663
664 memset(s, 0, sizeof(s));
665
666 while ((p = strsep(&buf, " ")) != NULL) {
667 if (!*p)
668 continue;
669
670 s[i++] = p;
671
672 /* Prevent from inputing too many things */
673 if (i == 3)
674 break;
675 }
676
677 if (i != 2)
678 return -EINVAL;
679
680 p = strsep(&s[0], ":");
681 if (p != NULL)
682 major_s = p;
683 else
684 return -EINVAL;
685
686 minor_s = s[0];
687 if (!minor_s)
688 return -EINVAL;
689
690 ret = strict_strtoul(major_s, 10, &major);
691 if (ret)
692 return -EINVAL;
693
694 ret = strict_strtoul(minor_s, 10, &minor);
695 if (ret)
696 return -EINVAL;
697
698 dev = MKDEV(major, minor);
699
700 ret = blkio_check_dev_num(dev);
701 if (ret)
702 return ret;
703
704 newpn->dev = dev;
705
706 if (s[1] == NULL)
707 return -EINVAL;
708
062a644d
VG		 709 switch (plid) {
710 case BLKIO_POLICY_PROP:
711 ret = strict_strtoul(s[1], 10, &temp);
712 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
713 temp > BLKIO_WEIGHT_MAX)
714 return -EINVAL;
34d0f179 715
062a644d
VG		 716 newpn->plid = plid;
717 newpn->fileid = fileid;
4c9eefa1
VG		 718 newpn->val.weight = temp;
719 break;
720 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 721 switch(fileid) {
722 case BLKIO_THROTL_read_bps_device:
723 case BLKIO_THROTL_write_bps_device:
724 ret = strict_strtoull(s[1], 10, &bps);
725 if (ret)
726 return -EINVAL;
4c9eefa1 727
7702e8f4
VG		 728 newpn->plid = plid;
729 newpn->fileid = fileid;
730 newpn->val.bps = bps;
731 break;
732 case BLKIO_THROTL_read_iops_device:
733 case BLKIO_THROTL_write_iops_device:
734 ret = strict_strtoul(s[1], 10, &iops);
735 if (ret)
736 return -EINVAL;
737
738 newpn->plid = plid;
739 newpn->fileid = fileid;
740 newpn->val.iops = iops;
741 break;
742 }
062a644d
VG		 743 break;
744 default:
745 BUG();
746 }
34d0f179
GJ		 747
748 return 0;
749}
750
751unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
752 dev_t dev)
753{
754 struct blkio_policy_node *pn;
755
062a644d
VG		 756 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
757 BLKIO_PROP_weight_device);
34d0f179 758 if (pn)
4c9eefa1 759 return pn->val.weight;
34d0f179
GJ		 760 else
761 return blkcg->weight;
762}
763EXPORT_SYMBOL_GPL(blkcg_get_weight);
764
4c9eefa1
VG		 765uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
766{
767 struct blkio_policy_node *pn;
768
769 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
770 BLKIO_THROTL_read_bps_device);
771 if (pn)
772 return pn->val.bps;
773 else
774 return -1;
775}
776
777uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
778{
779 struct blkio_policy_node *pn;
780 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
781 BLKIO_THROTL_write_bps_device);
782 if (pn)
783 return pn->val.bps;
784 else
785 return -1;
786}
787
7702e8f4
VG		 788unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
789{
790 struct blkio_policy_node *pn;
791
792 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
793 BLKIO_THROTL_read_iops_device);
794 if (pn)
795 return pn->val.iops;
796 else
797 return -1;
798}
799
800unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
801{
802 struct blkio_policy_node *pn;
803 pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
804 BLKIO_THROTL_write_iops_device);
805 if (pn)
806 return pn->val.iops;
807 else
808 return -1;
809}
810
062a644d
VG		 811/* Checks whether user asked for deleting a policy rule */
812static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
813{
814 switch(pn->plid) {
815 case BLKIO_POLICY_PROP:
4c9eefa1
VG		 816 if (pn->val.weight == 0)
817 return 1;
818 break;
819 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 820 switch(pn->fileid) {
821 case BLKIO_THROTL_read_bps_device:
822 case BLKIO_THROTL_write_bps_device:
823 if (pn->val.bps == 0)
824 return 1;
825 break;
826 case BLKIO_THROTL_read_iops_device:
827 case BLKIO_THROTL_write_iops_device:
828 if (pn->val.iops == 0)
829 return 1;
830 }
062a644d
VG		 831 break;
832 default:
833 BUG();
834 }
835
836 return 0;
837}
838
839static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
840 struct blkio_policy_node *newpn)
841{
842 switch(oldpn->plid) {
843 case BLKIO_POLICY_PROP:
4c9eefa1
VG		 844 oldpn->val.weight = newpn->val.weight;
845 break;
846 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 847 switch(newpn->fileid) {
848 case BLKIO_THROTL_read_bps_device:
849 case BLKIO_THROTL_write_bps_device:
850 oldpn->val.bps = newpn->val.bps;
851 break;
852 case BLKIO_THROTL_read_iops_device:
853 case BLKIO_THROTL_write_iops_device:
854 oldpn->val.iops = newpn->val.iops;
855 }
062a644d
VG		 856 break;
857 default:
858 BUG();
859 }
860}
861
862/*
863 * Some rules/values in blkg have changed. Propogate those to respective
864 * policies.
865 */
866static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
867 struct blkio_group *blkg, struct blkio_policy_node *pn)
868{
7702e8f4 869 unsigned int weight, iops;
4c9eefa1 870 u64 bps;
062a644d
VG		 871
872 switch(pn->plid) {
873 case BLKIO_POLICY_PROP:
4c9eefa1 874 weight = pn->val.weight ? pn->val.weight :
062a644d
VG		 875 blkcg->weight;
876 blkio_update_group_weight(blkg, weight);
877 break;
4c9eefa1
VG		 878 case BLKIO_POLICY_THROTL:
879 switch(pn->fileid) {
880 case BLKIO_THROTL_read_bps_device:
881 case BLKIO_THROTL_write_bps_device:
882 bps = pn->val.bps ? pn->val.bps : (-1);
883 blkio_update_group_bps(blkg, bps, pn->fileid);
884 break;
7702e8f4
VG		 885 case BLKIO_THROTL_read_iops_device:
886 case BLKIO_THROTL_write_iops_device:
887 iops = pn->val.iops ? pn->val.iops : (-1);
888 blkio_update_group_iops(blkg, iops, pn->fileid);
889 break;
4c9eefa1
VG		 890 }
891 break;
062a644d
VG		 892 default:
893 BUG();
894 }
895}
896
897/*
898 * A policy node rule has been updated. Propogate this update to all the
899 * block groups which might be affected by this update.
900 */
901static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
902 struct blkio_policy_node *pn)
903{
904 struct blkio_group *blkg;
905 struct hlist_node *n;
906
907 spin_lock(&blkio_list_lock);
908 spin_lock_irq(&blkcg->lock);
34d0f179 909
062a644d
VG		 910 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
911 if (pn->dev != blkg->dev || pn->plid != blkg->plid)
912 continue;
913 blkio_update_blkg_policy(blkcg, blkg, pn);
914 }
915
916 spin_unlock_irq(&blkcg->lock);
917 spin_unlock(&blkio_list_lock);
918}
919
920static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
921 const char *buffer)
34d0f179
GJ		 922{
923 int ret = 0;
924 char *buf;
925 struct blkio_policy_node *newpn, *pn;
926 struct blkio_cgroup *blkcg;
34d0f179 927 int keep_newpn = 0;
062a644d
VG		 928 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
929 int fileid = BLKIOFILE_ATTR(cft->private);
34d0f179
GJ		 930
931 buf = kstrdup(buffer, GFP_KERNEL);
932 if (!buf)
933 return -ENOMEM;
934
935 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
936 if (!newpn) {
937 ret = -ENOMEM;
938 goto free_buf;
939 }
940
062a644d 941 ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
34d0f179
GJ		 942 if (ret)
943 goto free_newpn;
944
945 blkcg = cgroup_to_blkio_cgroup(cgrp);
946
947 spin_lock_irq(&blkcg->lock);
948
062a644d 949 pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
34d0f179 950 if (!pn) {
062a644d 951 if (!blkio_delete_rule_command(newpn)) {
34d0f179
GJ		 952 blkio_policy_insert_node(blkcg, newpn);
953 keep_newpn = 1;
954 }
955 spin_unlock_irq(&blkcg->lock);
956 goto update_io_group;
957 }
958
062a644d 959 if (blkio_delete_rule_command(newpn)) {
34d0f179
GJ		 960 blkio_policy_delete_node(pn);
961 spin_unlock_irq(&blkcg->lock);
962 goto update_io_group;
963 }
964 spin_unlock_irq(&blkcg->lock);
965
062a644d 966 blkio_update_policy_rule(pn, newpn);
34d0f179
GJ		 967
968update_io_group:
062a644d 969 blkio_update_policy_node_blkg(blkcg, newpn);
34d0f179
GJ		 970
971free_newpn:
972 if (!keep_newpn)
973 kfree(newpn);
974free_buf:
975 kfree(buf);
976 return ret;
977}
978
062a644d
VG		 979static void
980blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
981{
982 switch(pn->plid) {
983 case BLKIO_POLICY_PROP:
984 if (pn->fileid == BLKIO_PROP_weight_device)
985 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
4c9eefa1
VG		 986 MINOR(pn->dev), pn->val.weight);
987 break;
988 case BLKIO_POLICY_THROTL:
7702e8f4
VG		 989 switch(pn->fileid) {
990 case BLKIO_THROTL_read_bps_device:
991 case BLKIO_THROTL_write_bps_device:
4c9eefa1
VG		 992 seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
993 MINOR(pn->dev), pn->val.bps);
7702e8f4
VG		 994 break;
995 case BLKIO_THROTL_read_iops_device:
996 case BLKIO_THROTL_write_iops_device:
997 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
998 MINOR(pn->dev), pn->val.iops);
999 break;
1000 }
062a644d
VG		 1001 break;
1002 default:
1003 BUG();
1004 }
1005}
1006
1007/* cgroup files which read their data from policy nodes end up here */
1008static void blkio_read_policy_node_files(struct cftype *cft,
1009 struct blkio_cgroup *blkcg, struct seq_file *m)
34d0f179 1010{
34d0f179
GJ		 1011 struct blkio_policy_node *pn;
1012
0f3942a3
JA		 1013 if (!list_empty(&blkcg->policy_list)) {
1014 spin_lock_irq(&blkcg->lock);
1015 list_for_each_entry(pn, &blkcg->policy_list, node) {
062a644d
VG		 1016 if (!pn_matches_cftype(cft, pn))
1017 continue;
1018 blkio_print_policy_node(m, pn);
0f3942a3
JA		 1019 }
1020 spin_unlock_irq(&blkcg->lock);
34d0f179 1021 }
062a644d
VG		 1022}
1023
1024static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
1025 struct seq_file *m)
1026{
1027 struct blkio_cgroup *blkcg;
1028 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1029 int name = BLKIOFILE_ATTR(cft->private);
1030
1031 blkcg = cgroup_to_blkio_cgroup(cgrp);
1032
1033 switch(plid) {
1034 case BLKIO_POLICY_PROP:
1035 switch(name) {
1036 case BLKIO_PROP_weight_device:
1037 blkio_read_policy_node_files(cft, blkcg, m);
1038 return 0;
1039 default:
1040 BUG();
1041 }
1042 break;
4c9eefa1
VG		 1043 case BLKIO_POLICY_THROTL:
1044 switch(name){
1045 case BLKIO_THROTL_read_bps_device:
1046 case BLKIO_THROTL_write_bps_device:
7702e8f4
VG		 1047 case BLKIO_THROTL_read_iops_device:
1048 case BLKIO_THROTL_write_iops_device:
4c9eefa1
VG		 1049 blkio_read_policy_node_files(cft, blkcg, m);
1050 return 0;
1051 default:
1052 BUG();
1053 }
1054 break;
062a644d
VG		 1055 default:
1056 BUG();
1057 }
1058
1059 return 0;
1060}
1061
1062static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
1063 struct cftype *cft, struct cgroup_map_cb *cb, enum stat_type type,
1064 bool show_total)
1065{
1066 struct blkio_group *blkg;
1067 struct hlist_node *n;
1068 uint64_t cgroup_total = 0;
1069
1070 rcu_read_lock();
1071 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
1072 if (blkg->dev) {
1073 if (!cftype_blkg_same_policy(cft, blkg))
1074 continue;
1075 spin_lock_irq(&blkg->stats_lock);
1076 cgroup_total += blkio_get_stat(blkg, cb, blkg->dev,
1077 type);
1078 spin_unlock_irq(&blkg->stats_lock);
1079 }
1080 }
1081 if (show_total)
1082 cb->fill(cb, "Total", cgroup_total);
1083 rcu_read_unlock();
1084 return 0;
1085}
1086
1087/* All map kind of cgroup file get serviced by this function */
1088static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
1089 struct cgroup_map_cb *cb)
1090{
1091 struct blkio_cgroup *blkcg;
1092 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1093 int name = BLKIOFILE_ATTR(cft->private);
1094
1095 blkcg = cgroup_to_blkio_cgroup(cgrp);
1096
1097 switch(plid) {
1098 case BLKIO_POLICY_PROP:
1099 switch(name) {
1100 case BLKIO_PROP_time:
1101 return blkio_read_blkg_stats(blkcg, cft, cb,
1102 BLKIO_STAT_TIME, 0);
1103 case BLKIO_PROP_sectors:
1104 return blkio_read_blkg_stats(blkcg, cft, cb,
1105 BLKIO_STAT_SECTORS, 0);
1106 case BLKIO_PROP_io_service_bytes:
1107 return blkio_read_blkg_stats(blkcg, cft, cb,
1108 BLKIO_STAT_SERVICE_BYTES, 1);
1109 case BLKIO_PROP_io_serviced:
1110 return blkio_read_blkg_stats(blkcg, cft, cb,
1111 BLKIO_STAT_SERVICED, 1);
1112 case BLKIO_PROP_io_service_time:
1113 return blkio_read_blkg_stats(blkcg, cft, cb,
1114 BLKIO_STAT_SERVICE_TIME, 1);
1115 case BLKIO_PROP_io_wait_time:
1116 return blkio_read_blkg_stats(blkcg, cft, cb,
1117 BLKIO_STAT_WAIT_TIME, 1);
1118 case BLKIO_PROP_io_merged:
1119 return blkio_read_blkg_stats(blkcg, cft, cb,
1120 BLKIO_STAT_MERGED, 1);
1121 case BLKIO_PROP_io_queued:
1122 return blkio_read_blkg_stats(blkcg, cft, cb,
1123 BLKIO_STAT_QUEUED, 1);
1124#ifdef CONFIG_DEBUG_BLK_CGROUP
1125 case BLKIO_PROP_dequeue:
1126 return blkio_read_blkg_stats(blkcg, cft, cb,
1127 BLKIO_STAT_DEQUEUE, 0);
1128 case BLKIO_PROP_avg_queue_size:
1129 return blkio_read_blkg_stats(blkcg, cft, cb,
1130 BLKIO_STAT_AVG_QUEUE_SIZE, 0);
1131 case BLKIO_PROP_group_wait_time:
1132 return blkio_read_blkg_stats(blkcg, cft, cb,
1133 BLKIO_STAT_GROUP_WAIT_TIME, 0);
1134 case BLKIO_PROP_idle_time:
1135 return blkio_read_blkg_stats(blkcg, cft, cb,
1136 BLKIO_STAT_IDLE_TIME, 0);
1137 case BLKIO_PROP_empty_time:
1138 return blkio_read_blkg_stats(blkcg, cft, cb,
1139 BLKIO_STAT_EMPTY_TIME, 0);
1140#endif
1141 default:
1142 BUG();
1143 }
1144 break;
4c9eefa1
VG		 1145 case BLKIO_POLICY_THROTL:
1146 switch(name){
1147 case BLKIO_THROTL_io_service_bytes:
1148 return blkio_read_blkg_stats(blkcg, cft, cb,
1149 BLKIO_STAT_SERVICE_BYTES, 1);
1150 case BLKIO_THROTL_io_serviced:
1151 return blkio_read_blkg_stats(blkcg, cft, cb,
1152 BLKIO_STAT_SERVICED, 1);
1153 default:
1154 BUG();
1155 }
1156 break;
062a644d
VG		 1157 default:
1158 BUG();
1159 }
1160
1161 return 0;
1162}
1163
1164static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
1165{
1166 struct blkio_group *blkg;
1167 struct hlist_node *n;
1168 struct blkio_policy_node *pn;
1169
1170 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
1171 return -EINVAL;
1172
1173 spin_lock(&blkio_list_lock);
1174 spin_lock_irq(&blkcg->lock);
1175 blkcg->weight = (unsigned int)val;
1176
1177 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
1178 pn = blkio_policy_search_node(blkcg, blkg->dev,
1179 BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
1180 if (pn)
1181 continue;
1182
1183 blkio_update_group_weight(blkg, blkcg->weight);
1184 }
1185 spin_unlock_irq(&blkcg->lock);
1186 spin_unlock(&blkio_list_lock);
1187 return 0;
1188}
1189
1190static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
1191 struct blkio_cgroup *blkcg;
1192 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1193 int name = BLKIOFILE_ATTR(cft->private);
1194
1195 blkcg = cgroup_to_blkio_cgroup(cgrp);
1196
1197 switch(plid) {
1198 case BLKIO_POLICY_PROP:
1199 switch(name) {
1200 case BLKIO_PROP_weight:
1201 return (u64)blkcg->weight;
1202 }
1203 break;
1204 default:
1205 BUG();
1206 }
1207 return 0;
1208}
1209
1210static int
1211blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
1212{
1213 struct blkio_cgroup *blkcg;
1214 enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
1215 int name = BLKIOFILE_ATTR(cft->private);
1216
1217 blkcg = cgroup_to_blkio_cgroup(cgrp);
1218
1219 switch(plid) {
1220 case BLKIO_POLICY_PROP:
1221 switch(name) {
1222 case BLKIO_PROP_weight:
1223 return blkio_weight_write(blkcg, val);
1224 }
1225 break;
1226 default:
1227 BUG();
1228 }
34d0f179 1229
34d0f179
GJ		 1230 return 0;
1231}
1232
31e4c28d 1233struct cftype blkio_files[] = {
34d0f179
GJ		 1234 {
1235 .name = "weight_device",
062a644d
VG		 1236 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1237 BLKIO_PROP_weight_device),
1238 .read_seq_string = blkiocg_file_read,
1239 .write_string = blkiocg_file_write,
34d0f179
GJ		 1240 .max_write_len = 256,
1241 },
31e4c28d
VG		 1242 {
1243 .name = "weight",
062a644d
VG		 1244 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1245 BLKIO_PROP_weight),
1246 .read_u64 = blkiocg_file_read_u64,
1247 .write_u64 = blkiocg_file_write_u64,
31e4c28d 1248 },
22084190
VG		 1249 {
1250 .name = "time",
062a644d
VG		 1251 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1252 BLKIO_PROP_time),
1253 .read_map = blkiocg_file_read_map,
22084190
VG		 1254 },
1255 {
1256 .name = "sectors",
062a644d
VG		 1257 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1258 BLKIO_PROP_sectors),
1259 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1260 },
1261 {
1262 .name = "io_service_bytes",
062a644d
VG		 1263 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1264 BLKIO_PROP_io_service_bytes),
1265 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1266 },
1267 {
1268 .name = "io_serviced",
062a644d
VG		 1269 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1270 BLKIO_PROP_io_serviced),
1271 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1272 },
1273 {
1274 .name = "io_service_time",
062a644d
VG		 1275 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1276 BLKIO_PROP_io_service_time),
1277 .read_map = blkiocg_file_read_map,
303a3acb
DS		 1278 },
1279 {
1280 .name = "io_wait_time",
062a644d
VG		 1281 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1282 BLKIO_PROP_io_wait_time),
1283 .read_map = blkiocg_file_read_map,
84c124da 1284 },
812d4026
DS		 1285 {
1286 .name = "io_merged",
062a644d
VG		 1287 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1288 BLKIO_PROP_io_merged),
1289 .read_map = blkiocg_file_read_map,
812d4026 1290 },
cdc1184c
DS		 1291 {
1292 .name = "io_queued",
062a644d
VG		 1293 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1294 BLKIO_PROP_io_queued),
1295 .read_map = blkiocg_file_read_map,
cdc1184c 1296 },
84c124da
DS		 1297 {
1298 .name = "reset_stats",
1299 .write_u64 = blkiocg_reset_stats,
22084190 1300 },
13f98250
VG		 1301#ifdef CONFIG_BLK_DEV_THROTTLING
1302 {
1303 .name = "throttle.read_bps_device",
1304 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1305 BLKIO_THROTL_read_bps_device),
1306 .read_seq_string = blkiocg_file_read,
1307 .write_string = blkiocg_file_write,
1308 .max_write_len = 256,
1309 },
1310
1311 {
1312 .name = "throttle.write_bps_device",
1313 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1314 BLKIO_THROTL_write_bps_device),
1315 .read_seq_string = blkiocg_file_read,
1316 .write_string = blkiocg_file_write,
1317 .max_write_len = 256,
1318 },
1319
1320 {
1321 .name = "throttle.read_iops_device",
1322 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1323 BLKIO_THROTL_read_iops_device),
1324 .read_seq_string = blkiocg_file_read,
1325 .write_string = blkiocg_file_write,
1326 .max_write_len = 256,
1327 },
1328
1329 {
1330 .name = "throttle.write_iops_device",
1331 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1332 BLKIO_THROTL_write_iops_device),
1333 .read_seq_string = blkiocg_file_read,
1334 .write_string = blkiocg_file_write,
1335 .max_write_len = 256,
1336 },
1337 {
1338 .name = "throttle.io_service_bytes",
1339 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1340 BLKIO_THROTL_io_service_bytes),
1341 .read_map = blkiocg_file_read_map,
1342 },
1343 {
1344 .name = "throttle.io_serviced",
1345 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
1346 BLKIO_THROTL_io_serviced),
1347 .read_map = blkiocg_file_read_map,
1348 },
1349#endif /* CONFIG_BLK_DEV_THROTTLING */
1350
22084190 1351#ifdef CONFIG_DEBUG_BLK_CGROUP
cdc1184c
DS		 1352 {
1353 .name = "avg_queue_size",
062a644d
VG		 1354 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1355 BLKIO_PROP_avg_queue_size),
1356 .read_map = blkiocg_file_read_map,
cdc1184c 1357 },
812df48d
DS		 1358 {
1359 .name = "group_wait_time",
062a644d
VG		 1360 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1361 BLKIO_PROP_group_wait_time),
1362 .read_map = blkiocg_file_read_map,
812df48d
DS		 1363 },
1364 {
1365 .name = "idle_time",
062a644d
VG		 1366 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1367 BLKIO_PROP_idle_time),
1368 .read_map = blkiocg_file_read_map,
812df48d
DS		 1369 },
1370 {
1371 .name = "empty_time",
062a644d
VG		 1372 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1373 BLKIO_PROP_empty_time),
1374 .read_map = blkiocg_file_read_map,
812df48d 1375 },
cdc1184c 1376 {
22084190 1377 .name = "dequeue",
062a644d
VG		 1378 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
1379 BLKIO_PROP_dequeue),
1380 .read_map = blkiocg_file_read_map,
cdc1184c 1381 },
22084190 1382#endif
31e4c28d
VG		 1383};
1384
1385static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1386{
1387 return cgroup_add_files(cgroup, subsys, blkio_files,
1388 ARRAY_SIZE(blkio_files));
1389}
1390
1391static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1392{
1393 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
b1c35769
VG		 1394 unsigned long flags;
1395 struct blkio_group *blkg;
1396 void *key;
3e252066 1397 struct blkio_policy_type *blkiop;
34d0f179 1398 struct blkio_policy_node *pn, *pntmp;
b1c35769
VG		 1399
1400 rcu_read_lock();
0f3942a3
JA		 1401 do {
1402 spin_lock_irqsave(&blkcg->lock, flags);
b1c35769 1403
0f3942a3
JA		 1404 if (hlist_empty(&blkcg->blkg_list)) {
1405 spin_unlock_irqrestore(&blkcg->lock, flags);
1406 break;
1407 }
b1c35769 1408
0f3942a3
JA		 1409 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
1410 blkcg_node);
1411 key = rcu_dereference(blkg->key);
1412 __blkiocg_del_blkio_group(blkg);
31e4c28d 1413
0f3942a3 1414 spin_unlock_irqrestore(&blkcg->lock, flags);
b1c35769 1415
0f3942a3
JA		 1416 /*
1417 * This blkio_group is being unlinked as associated cgroup is
1418 * going away. Let all the IO controlling policies know about
61014e96 1419 * this event.
0f3942a3
JA		 1420 */
1421 spin_lock(&blkio_list_lock);
61014e96
VG		 1422 list_for_each_entry(blkiop, &blkio_list, list) {
1423 if (blkiop->plid != blkg->plid)
1424 continue;
0f3942a3 1425 blkiop->ops.blkio_unlink_group_fn(key, blkg);
61014e96 1426 }
0f3942a3
JA		 1427 spin_unlock(&blkio_list_lock);
1428 } while (1);
34d0f179 1429
34d0f179
GJ		 1430 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
1431 blkio_policy_delete_node(pn);
1432 kfree(pn);
1433 }
0f3942a3 1434
31e4c28d 1435 free_css_id(&blkio_subsys, &blkcg->css);
b1c35769 1436 rcu_read_unlock();
67523c48
BB		 1437 if (blkcg != &blkio_root_cgroup)
1438 kfree(blkcg);
31e4c28d
VG		 1439}
1440
1441static struct cgroup_subsys_state *
1442blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
1443{
0341509f
LZ		 1444 struct blkio_cgroup *blkcg;
1445 struct cgroup *parent = cgroup->parent;
31e4c28d 1446
0341509f 1447 if (!parent) {
31e4c28d
VG		 1448 blkcg = &blkio_root_cgroup;
1449 goto done;
1450 }
1451
1452 /* Currently we do not support hierarchy deeper than two level (0,1) */
0341509f 1453 if (parent != cgroup->top_cgroup)
31e4c28d
VG		 1454 return ERR_PTR(-EINVAL);
1455
1456 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
1457 if (!blkcg)
1458 return ERR_PTR(-ENOMEM);
1459
1460 blkcg->weight = BLKIO_WEIGHT_DEFAULT;
1461done:
1462 spin_lock_init(&blkcg->lock);
1463 INIT_HLIST_HEAD(&blkcg->blkg_list);
1464
34d0f179 1465 INIT_LIST_HEAD(&blkcg->policy_list);
31e4c28d
VG		 1466 return &blkcg->css;
1467}
1468
1469/*
1470 * We cannot support shared io contexts, as we have no mean to support
1471 * two tasks with the same ioc in two different groups without major rework
1472 * of the main cic data structures. For now we allow a task to change
1473 * its cgroup only if it's the only owner of its ioc.
1474 */
1475static int blkiocg_can_attach(struct cgroup_subsys *subsys,
1476 struct cgroup *cgroup, struct task_struct *tsk,
1477 bool threadgroup)
1478{
1479 struct io_context *ioc;
1480 int ret = 0;
1481
1482 /* task_lock() is needed to avoid races with exit_io_context() */
1483 task_lock(tsk);
1484 ioc = tsk->io_context;
1485 if (ioc && atomic_read(&ioc->nr_tasks) > 1)
1486 ret = -EINVAL;
1487 task_unlock(tsk);
1488
1489 return ret;
1490}
1491
1492static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup,
1493 struct cgroup *prev, struct task_struct *tsk,
1494 bool threadgroup)
1495{
1496 struct io_context *ioc;
1497
1498 task_lock(tsk);
1499 ioc = tsk->io_context;
1500 if (ioc)
1501 ioc->cgroup_changed = 1;
1502 task_unlock(tsk);
1503}
1504
3e252066
VG		 1505void blkio_policy_register(struct blkio_policy_type *blkiop)
1506{
1507 spin_lock(&blkio_list_lock);
1508 list_add_tail(&blkiop->list, &blkio_list);
1509 spin_unlock(&blkio_list_lock);
1510}
1511EXPORT_SYMBOL_GPL(blkio_policy_register);
1512
1513void blkio_policy_unregister(struct blkio_policy_type *blkiop)
1514{
1515 spin_lock(&blkio_list_lock);
1516 list_del_init(&blkiop->list);
1517 spin_unlock(&blkio_list_lock);
1518}
1519EXPORT_SYMBOL_GPL(blkio_policy_unregister);
67523c48
BB		 1520
1521static int __init init_cgroup_blkio(void)
1522{
1523 return cgroup_load_subsys(&blkio_subsys);
1524}
1525
1526static void __exit exit_cgroup_blkio(void)
1527{
1528 cgroup_unload_subsys(&blkio_subsys);
1529}
1530
1531module_init(init_cgroup_blkio);
1532module_exit(exit_cgroup_blkio);
1533MODULE_LICENSE("GPL");
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