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block: Update to io-controller stats
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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>
14 #include <linux/seq_file.h>
15 #include <linux/kdev_t.h>
16 #include <linux/module.h>
17 #include <linux/err.h>
18 #include <linux/blkdev.h>
19 #include "blk-cgroup.h"
20 #include <linux/genhd.h>
21
22 #define MAX_KEY_LEN 100
23
24 static DEFINE_SPINLOCK(blkio_list_lock);
25 static LIST_HEAD(blkio_list);
26
27 struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
28 EXPORT_SYMBOL_GPL(blkio_root_cgroup);
29
30 static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
31 struct cgroup *);
32 static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
33 struct task_struct *, bool);
34 static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,
35 struct cgroup *, struct task_struct *, bool);
36 static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
37 static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
38
39 struct cgroup_subsys blkio_subsys = {
40 .name = "blkio",
41 .create = blkiocg_create,
42 .can_attach = blkiocg_can_attach,
43 .attach = blkiocg_attach,
44 .destroy = blkiocg_destroy,
45 .populate = blkiocg_populate,
46 #ifdef CONFIG_BLK_CGROUP
47 /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
48 .subsys_id = blkio_subsys_id,
49 #endif
50 .use_id = 1,
51 .module = THIS_MODULE,
52 };
53 EXPORT_SYMBOL_GPL(blkio_subsys);
54
55 static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
56 struct blkio_policy_node *pn)
57 {
58 list_add(&pn->node, &blkcg->policy_list);
59 }
60
61 /* Must be called with blkcg->lock held */
62 static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
63 {
64 list_del(&pn->node);
65 }
66
67 /* Must be called with blkcg->lock held */
68 static struct blkio_policy_node *
69 blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev)
70 {
71 struct blkio_policy_node *pn;
72
73 list_for_each_entry(pn, &blkcg->policy_list, node) {
74 if (pn->dev == dev)
75 return pn;
76 }
77
78 return NULL;
79 }
80
81 struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
82 {
83 return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
84 struct blkio_cgroup, css);
85 }
86 EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
87
88 void blkio_group_init(struct blkio_group *blkg)
89 {
90 spin_lock_init(&blkg->stats_lock);
91 }
92 EXPORT_SYMBOL_GPL(blkio_group_init);
93
94 /*
95 * Add to the appropriate stat variable depending on the request type.
96 * This should be called with the blkg->stats_lock held.
97 */
98 static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
99 bool sync)
100 {
101 if (direction)
102 stat[BLKIO_STAT_WRITE] += add;
103 else
104 stat[BLKIO_STAT_READ] += add;
105 if (sync)
106 stat[BLKIO_STAT_SYNC] += add;
107 else
108 stat[BLKIO_STAT_ASYNC] += add;
109 }
110
111 /*
112 * Decrements the appropriate stat variable if non-zero depending on the
113 * request type. Panics on value being zero.
114 * This should be called with the blkg->stats_lock held.
115 */
116 static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
117 {
118 if (direction) {
119 BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
120 stat[BLKIO_STAT_WRITE]--;
121 } else {
122 BUG_ON(stat[BLKIO_STAT_READ] == 0);
123 stat[BLKIO_STAT_READ]--;
124 }
125 if (sync) {
126 BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
127 stat[BLKIO_STAT_SYNC]--;
128 } else {
129 BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
130 stat[BLKIO_STAT_ASYNC]--;
131 }
132 }
133
134 #ifdef CONFIG_DEBUG_BLK_CGROUP
135 /* This should be called with the blkg->stats_lock held. */
136 static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
137 struct blkio_group *curr_blkg)
138 {
139 if (blkio_blkg_waiting(&blkg->stats))
140 return;
141 if (blkg == curr_blkg)
142 return;
143 blkg->stats.start_group_wait_time = sched_clock();
144 blkio_mark_blkg_waiting(&blkg->stats);
145 }
146
147 /* This should be called with the blkg->stats_lock held. */
148 static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
149 {
150 unsigned long long now;
151
152 if (!blkio_blkg_waiting(stats))
153 return;
154
155 now = sched_clock();
156 if (time_after64(now, stats->start_group_wait_time))
157 stats->group_wait_time += now - stats->start_group_wait_time;
158 blkio_clear_blkg_waiting(stats);
159 }
160
161 /* This should be called with the blkg->stats_lock held. */
162 static void blkio_end_empty_time(struct blkio_group_stats *stats)
163 {
164 unsigned long long now;
165
166 if (!blkio_blkg_empty(stats))
167 return;
168
169 now = sched_clock();
170 if (time_after64(now, stats->start_empty_time))
171 stats->empty_time += now - stats->start_empty_time;
172 blkio_clear_blkg_empty(stats);
173 }
174
175 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
176 {
177 unsigned long flags;
178
179 spin_lock_irqsave(&blkg->stats_lock, flags);
180 BUG_ON(blkio_blkg_idling(&blkg->stats));
181 blkg->stats.start_idle_time = sched_clock();
182 blkio_mark_blkg_idling(&blkg->stats);
183 spin_unlock_irqrestore(&blkg->stats_lock, flags);
184 }
185 EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
186
187 void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
188 {
189 unsigned long flags;
190 unsigned long long now;
191 struct blkio_group_stats *stats;
192
193 spin_lock_irqsave(&blkg->stats_lock, flags);
194 stats = &blkg->stats;
195 if (blkio_blkg_idling(stats)) {
196 now = sched_clock();
197 if (time_after64(now, stats->start_idle_time))
198 stats->idle_time += now - stats->start_idle_time;
199 blkio_clear_blkg_idling(stats);
200 }
201 spin_unlock_irqrestore(&blkg->stats_lock, flags);
202 }
203 EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
204
205 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
206 {
207 unsigned long flags;
208 struct blkio_group_stats *stats;
209
210 spin_lock_irqsave(&blkg->stats_lock, flags);
211 stats = &blkg->stats;
212 stats->avg_queue_size_sum +=
213 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
214 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
215 stats->avg_queue_size_samples++;
216 blkio_update_group_wait_time(stats);
217 spin_unlock_irqrestore(&blkg->stats_lock, flags);
218 }
219 EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
220
221 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
222 unsigned long dequeue)
223 {
224 blkg->stats.dequeue += dequeue;
225 }
226 EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
227 #else
228 static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
229 struct blkio_group *curr_blkg) {}
230 static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
231 #endif
232
233 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
234 struct blkio_group *curr_blkg, bool direction,
235 bool sync)
236 {
237 unsigned long flags;
238
239 spin_lock_irqsave(&blkg->stats_lock, flags);
240 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
241 sync);
242 blkio_end_empty_time(&blkg->stats);
243 blkio_set_start_group_wait_time(blkg, curr_blkg);
244 spin_unlock_irqrestore(&blkg->stats_lock, flags);
245 }
246 EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
247
248 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
249 bool direction, bool sync)
250 {
251 unsigned long flags;
252
253 spin_lock_irqsave(&blkg->stats_lock, flags);
254 blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
255 direction, sync);
256 spin_unlock_irqrestore(&blkg->stats_lock, flags);
257 }
258 EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
259
260 void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
261 {
262 unsigned long flags;
263
264 spin_lock_irqsave(&blkg->stats_lock, flags);
265 blkg->stats.time += time;
266 spin_unlock_irqrestore(&blkg->stats_lock, flags);
267 }
268 EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
269
270 void blkiocg_set_start_empty_time(struct blkio_group *blkg, bool ignore)
271 {
272 unsigned long flags;
273 struct blkio_group_stats *stats;
274
275 spin_lock_irqsave(&blkg->stats_lock, flags);
276 stats = &blkg->stats;
277
278 if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
279 stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
280 spin_unlock_irqrestore(&blkg->stats_lock, flags);
281 return;
282 }
283
284 /*
285 * If ignore is set, we do not panic on the empty flag being set
286 * already. This is to avoid cases where there are superfluous timeslice
287 * complete events (for eg., forced_dispatch in CFQ) when no IOs are
288 * served which could result in triggering the empty check incorrectly.
289 */
290 BUG_ON(!ignore && blkio_blkg_empty(stats));
291 stats->start_empty_time = sched_clock();
292 blkio_mark_blkg_empty(stats);
293 spin_unlock_irqrestore(&blkg->stats_lock, flags);
294 }
295 EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
296
297 void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
298 uint64_t bytes, bool direction, bool sync)
299 {
300 struct blkio_group_stats *stats;
301 unsigned long flags;
302
303 spin_lock_irqsave(&blkg->stats_lock, flags);
304 stats = &blkg->stats;
305 stats->sectors += bytes >> 9;
306 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
307 sync);
308 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
309 direction, sync);
310 spin_unlock_irqrestore(&blkg->stats_lock, flags);
311 }
312 EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
313
314 void blkiocg_update_completion_stats(struct blkio_group *blkg,
315 uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
316 {
317 struct blkio_group_stats *stats;
318 unsigned long flags;
319 unsigned long long now = sched_clock();
320
321 spin_lock_irqsave(&blkg->stats_lock, flags);
322 stats = &blkg->stats;
323 if (time_after64(now, io_start_time))
324 blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
325 now - io_start_time, direction, sync);
326 if (time_after64(io_start_time, start_time))
327 blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
328 io_start_time - start_time, direction, sync);
329 spin_unlock_irqrestore(&blkg->stats_lock, flags);
330 }
331 EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
332
333 void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
334 bool sync)
335 {
336 unsigned long flags;
337
338 spin_lock_irqsave(&blkg->stats_lock, flags);
339 blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,
340 sync);
341 spin_unlock_irqrestore(&blkg->stats_lock, flags);
342 }
343 EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
344
345 void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
346 struct blkio_group *blkg, void *key, dev_t dev)
347 {
348 unsigned long flags;
349
350 spin_lock_irqsave(&blkcg->lock, flags);
351 rcu_assign_pointer(blkg->key, key);
352 blkg->blkcg_id = css_id(&blkcg->css);
353 hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
354 spin_unlock_irqrestore(&blkcg->lock, flags);
355 #ifdef CONFIG_DEBUG_BLK_CGROUP
356 /* Need to take css reference ? */
357 cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
358 #endif
359 blkg->dev = dev;
360 }
361 EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
362
363 static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
364 {
365 hlist_del_init_rcu(&blkg->blkcg_node);
366 blkg->blkcg_id = 0;
367 }
368
369 /*
370 * returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
371 * indicating that blk_group was unhashed by the time we got to it.
372 */
373 int blkiocg_del_blkio_group(struct blkio_group *blkg)
374 {
375 struct blkio_cgroup *blkcg;
376 unsigned long flags;
377 struct cgroup_subsys_state *css;
378 int ret = 1;
379
380 rcu_read_lock();
381 css = css_lookup(&blkio_subsys, blkg->blkcg_id);
382 if (!css)
383 goto out;
384
385 blkcg = container_of(css, struct blkio_cgroup, css);
386 spin_lock_irqsave(&blkcg->lock, flags);
387 if (!hlist_unhashed(&blkg->blkcg_node)) {
388 __blkiocg_del_blkio_group(blkg);
389 ret = 0;
390 }
391 spin_unlock_irqrestore(&blkcg->lock, flags);
392 out:
393 rcu_read_unlock();
394 return ret;
395 }
396 EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
397
398 /* called under rcu_read_lock(). */
399 struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
400 {
401 struct blkio_group *blkg;
402 struct hlist_node *n;
403 void *__key;
404
405 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
406 __key = blkg->key;
407 if (__key == key)
408 return blkg;
409 }
410
411 return NULL;
412 }
413 EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
414
415 #define SHOW_FUNCTION(__VAR) \
416 static u64 blkiocg_##__VAR##_read(struct cgroup *cgroup, \
417 struct cftype *cftype) \
418 { \
419 struct blkio_cgroup *blkcg; \
420 \
421 blkcg = cgroup_to_blkio_cgroup(cgroup); \
422 return (u64)blkcg->__VAR; \
423 }
424
425 SHOW_FUNCTION(weight);
426 #undef SHOW_FUNCTION
427
428 static int
429 blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
430 {
431 struct blkio_cgroup *blkcg;
432 struct blkio_group *blkg;
433 struct hlist_node *n;
434 struct blkio_policy_type *blkiop;
435 struct blkio_policy_node *pn;
436
437 if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
438 return -EINVAL;
439
440 blkcg = cgroup_to_blkio_cgroup(cgroup);
441 spin_lock(&blkio_list_lock);
442 spin_lock_irq(&blkcg->lock);
443 blkcg->weight = (unsigned int)val;
444
445 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
446 pn = blkio_policy_search_node(blkcg, blkg->dev);
447
448 if (pn)
449 continue;
450
451 list_for_each_entry(blkiop, &blkio_list, list)
452 blkiop->ops.blkio_update_group_weight_fn(blkg,
453 blkcg->weight);
454 }
455 spin_unlock_irq(&blkcg->lock);
456 spin_unlock(&blkio_list_lock);
457 return 0;
458 }
459
460 static int
461 blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
462 {
463 struct blkio_cgroup *blkcg;
464 struct blkio_group *blkg;
465 struct blkio_group_stats *stats;
466 struct hlist_node *n;
467 uint64_t queued[BLKIO_STAT_TOTAL];
468 int i;
469 #ifdef CONFIG_DEBUG_BLK_CGROUP
470 bool idling, waiting, empty;
471 unsigned long long now = sched_clock();
472 #endif
473
474 blkcg = cgroup_to_blkio_cgroup(cgroup);
475 spin_lock_irq(&blkcg->lock);
476 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
477 spin_lock(&blkg->stats_lock);
478 stats = &blkg->stats;
479 #ifdef CONFIG_DEBUG_BLK_CGROUP
480 idling = blkio_blkg_idling(stats);
481 waiting = blkio_blkg_waiting(stats);
482 empty = blkio_blkg_empty(stats);
483 #endif
484 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
485 queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
486 memset(stats, 0, sizeof(struct blkio_group_stats));
487 for (i = 0; i < BLKIO_STAT_TOTAL; i++)
488 stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
489 #ifdef CONFIG_DEBUG_BLK_CGROUP
490 if (idling) {
491 blkio_mark_blkg_idling(stats);
492 stats->start_idle_time = now;
493 }
494 if (waiting) {
495 blkio_mark_blkg_waiting(stats);
496 stats->start_group_wait_time = now;
497 }
498 if (empty) {
499 blkio_mark_blkg_empty(stats);
500 stats->start_empty_time = now;
501 }
502 #endif
503 spin_unlock(&blkg->stats_lock);
504 }
505 spin_unlock_irq(&blkcg->lock);
506 return 0;
507 }
508
509 static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
510 int chars_left, bool diskname_only)
511 {
512 snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
513 chars_left -= strlen(str);
514 if (chars_left <= 0) {
515 printk(KERN_WARNING
516 "Possibly incorrect cgroup stat display format");
517 return;
518 }
519 if (diskname_only)
520 return;
521 switch (type) {
522 case BLKIO_STAT_READ:
523 strlcat(str, " Read", chars_left);
524 break;
525 case BLKIO_STAT_WRITE:
526 strlcat(str, " Write", chars_left);
527 break;
528 case BLKIO_STAT_SYNC:
529 strlcat(str, " Sync", chars_left);
530 break;
531 case BLKIO_STAT_ASYNC:
532 strlcat(str, " Async", chars_left);
533 break;
534 case BLKIO_STAT_TOTAL:
535 strlcat(str, " Total", chars_left);
536 break;
537 default:
538 strlcat(str, " Invalid", chars_left);
539 }
540 }
541
542 static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
543 struct cgroup_map_cb *cb, dev_t dev)
544 {
545 blkio_get_key_name(0, dev, str, chars_left, true);
546 cb->fill(cb, str, val);
547 return val;
548 }
549
550 /* This should be called with blkg->stats_lock held */
551 static uint64_t blkio_get_stat(struct blkio_group *blkg,
552 struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
553 {
554 uint64_t disk_total;
555 char key_str[MAX_KEY_LEN];
556 enum stat_sub_type sub_type;
557
558 if (type == BLKIO_STAT_TIME)
559 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
560 blkg->stats.time, cb, dev);
561 if (type == BLKIO_STAT_SECTORS)
562 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
563 blkg->stats.sectors, cb, dev);
564 #ifdef CONFIG_DEBUG_BLK_CGROUP
565 if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
566 uint64_t sum = blkg->stats.avg_queue_size_sum;
567 uint64_t samples = blkg->stats.avg_queue_size_samples;
568 if (samples)
569 do_div(sum, samples);
570 else
571 sum = 0;
572 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
573 }
574 if (type == BLKIO_STAT_GROUP_WAIT_TIME)
575 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
576 blkg->stats.group_wait_time, cb, dev);
577 if (type == BLKIO_STAT_IDLE_TIME)
578 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
579 blkg->stats.idle_time, cb, dev);
580 if (type == BLKIO_STAT_EMPTY_TIME)
581 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
582 blkg->stats.empty_time, cb, dev);
583 if (type == BLKIO_STAT_DEQUEUE)
584 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
585 blkg->stats.dequeue, cb, dev);
586 #endif
587
588 for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
589 sub_type++) {
590 blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
591 cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
592 }
593 disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
594 blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
595 blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
596 cb->fill(cb, key_str, disk_total);
597 return disk_total;
598 }
599
600 #define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \
601 static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \
602 struct cftype *cftype, struct cgroup_map_cb *cb) \
603 { \
604 struct blkio_cgroup *blkcg; \
605 struct blkio_group *blkg; \
606 struct hlist_node *n; \
607 uint64_t cgroup_total = 0; \
608 \
609 if (!cgroup_lock_live_group(cgroup)) \
610 return -ENODEV; \
611 \
612 blkcg = cgroup_to_blkio_cgroup(cgroup); \
613 rcu_read_lock(); \
614 hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\
615 if (blkg->dev) { \
616 spin_lock_irq(&blkg->stats_lock); \
617 cgroup_total += blkio_get_stat(blkg, cb, \
618 blkg->dev, type); \
619 spin_unlock_irq(&blkg->stats_lock); \
620 } \
621 } \
622 if (show_total) \
623 cb->fill(cb, "Total", cgroup_total); \
624 rcu_read_unlock(); \
625 cgroup_unlock(); \
626 return 0; \
627 }
628
629 SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0);
630 SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0);
631 SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1);
632 SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1);
633 SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1);
634 SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1);
635 SHOW_FUNCTION_PER_GROUP(io_merged, BLKIO_STAT_MERGED, 1);
636 SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1);
637 #ifdef CONFIG_DEBUG_BLK_CGROUP
638 SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0);
639 SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0);
640 SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0);
641 SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0);
642 SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0);
643 #endif
644 #undef SHOW_FUNCTION_PER_GROUP
645
646 static int blkio_check_dev_num(dev_t dev)
647 {
648 int part = 0;
649 struct gendisk *disk;
650
651 disk = get_gendisk(dev, &part);
652 if (!disk || part)
653 return -ENODEV;
654
655 return 0;
656 }
657
658 static int blkio_policy_parse_and_set(char *buf,
659 struct blkio_policy_node *newpn)
660 {
661 char *s[4], *p, *major_s = NULL, *minor_s = NULL;
662 int ret;
663 unsigned long major, minor, temp;
664 int i = 0;
665 dev_t dev;
666
667 memset(s, 0, sizeof(s));
668
669 while ((p = strsep(&buf, " ")) != NULL) {
670 if (!*p)
671 continue;
672
673 s[i++] = p;
674
675 /* Prevent from inputing too many things */
676 if (i == 3)
677 break;
678 }
679
680 if (i != 2)
681 return -EINVAL;
682
683 p = strsep(&s[0], ":");
684 if (p != NULL)
685 major_s = p;
686 else
687 return -EINVAL;
688
689 minor_s = s[0];
690 if (!minor_s)
691 return -EINVAL;
692
693 ret = strict_strtoul(major_s, 10, &major);
694 if (ret)
695 return -EINVAL;
696
697 ret = strict_strtoul(minor_s, 10, &minor);
698 if (ret)
699 return -EINVAL;
700
701 dev = MKDEV(major, minor);
702
703 ret = blkio_check_dev_num(dev);
704 if (ret)
705 return ret;
706
707 newpn->dev = dev;
708
709 if (s[1] == NULL)
710 return -EINVAL;
711
712 ret = strict_strtoul(s[1], 10, &temp);
713 if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||
714 temp > BLKIO_WEIGHT_MAX)
715 return -EINVAL;
716
717 newpn->weight = temp;
718
719 return 0;
720 }
721
722 unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
723 dev_t dev)
724 {
725 struct blkio_policy_node *pn;
726
727 pn = blkio_policy_search_node(blkcg, dev);
728 if (pn)
729 return pn->weight;
730 else
731 return blkcg->weight;
732 }
733 EXPORT_SYMBOL_GPL(blkcg_get_weight);
734
735
736 static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,
737 const char *buffer)
738 {
739 int ret = 0;
740 char *buf;
741 struct blkio_policy_node *newpn, *pn;
742 struct blkio_cgroup *blkcg;
743 struct blkio_group *blkg;
744 int keep_newpn = 0;
745 struct hlist_node *n;
746 struct blkio_policy_type *blkiop;
747
748 buf = kstrdup(buffer, GFP_KERNEL);
749 if (!buf)
750 return -ENOMEM;
751
752 newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
753 if (!newpn) {
754 ret = -ENOMEM;
755 goto free_buf;
756 }
757
758 ret = blkio_policy_parse_and_set(buf, newpn);
759 if (ret)
760 goto free_newpn;
761
762 blkcg = cgroup_to_blkio_cgroup(cgrp);
763
764 spin_lock_irq(&blkcg->lock);
765
766 pn = blkio_policy_search_node(blkcg, newpn->dev);
767 if (!pn) {
768 if (newpn->weight != 0) {
769 blkio_policy_insert_node(blkcg, newpn);
770 keep_newpn = 1;
771 }
772 spin_unlock_irq(&blkcg->lock);
773 goto update_io_group;
774 }
775
776 if (newpn->weight == 0) {
777 /* weight == 0 means deleteing a specific weight */
778 blkio_policy_delete_node(pn);
779 spin_unlock_irq(&blkcg->lock);
780 goto update_io_group;
781 }
782 spin_unlock_irq(&blkcg->lock);
783
784 pn->weight = newpn->weight;
785
786 update_io_group:
787 /* update weight for each cfqg */
788 spin_lock(&blkio_list_lock);
789 spin_lock_irq(&blkcg->lock);
790
791 hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
792 if (newpn->dev == blkg->dev) {
793 list_for_each_entry(blkiop, &blkio_list, list)
794 blkiop->ops.blkio_update_group_weight_fn(blkg,
795 newpn->weight ?
796 newpn->weight :
797 blkcg->weight);
798 }
799 }
800
801 spin_unlock_irq(&blkcg->lock);
802 spin_unlock(&blkio_list_lock);
803
804 free_newpn:
805 if (!keep_newpn)
806 kfree(newpn);
807 free_buf:
808 kfree(buf);
809 return ret;
810 }
811
812 static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,
813 struct seq_file *m)
814 {
815 struct blkio_cgroup *blkcg;
816 struct blkio_policy_node *pn;
817
818 seq_printf(m, "dev\tweight\n");
819
820 blkcg = cgroup_to_blkio_cgroup(cgrp);
821 if (list_empty(&blkcg->policy_list))
822 goto out;
823
824 spin_lock_irq(&blkcg->lock);
825 list_for_each_entry(pn, &blkcg->policy_list, node) {
826 seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
827 MINOR(pn->dev), pn->weight);
828 }
829 spin_unlock_irq(&blkcg->lock);
830
831 out:
832 return 0;
833 }
834
835 struct cftype blkio_files[] = {
836 {
837 .name = "weight_device",
838 .read_seq_string = blkiocg_weight_device_read,
839 .write_string = blkiocg_weight_device_write,
840 .max_write_len = 256,
841 },
842 {
843 .name = "weight",
844 .read_u64 = blkiocg_weight_read,
845 .write_u64 = blkiocg_weight_write,
846 },
847 {
848 .name = "time",
849 .read_map = blkiocg_time_read,
850 },
851 {
852 .name = "sectors",
853 .read_map = blkiocg_sectors_read,
854 },
855 {
856 .name = "io_service_bytes",
857 .read_map = blkiocg_io_service_bytes_read,
858 },
859 {
860 .name = "io_serviced",
861 .read_map = blkiocg_io_serviced_read,
862 },
863 {
864 .name = "io_service_time",
865 .read_map = blkiocg_io_service_time_read,
866 },
867 {
868 .name = "io_wait_time",
869 .read_map = blkiocg_io_wait_time_read,
870 },
871 {
872 .name = "io_merged",
873 .read_map = blkiocg_io_merged_read,
874 },
875 {
876 .name = "io_queued",
877 .read_map = blkiocg_io_queued_read,
878 },
879 {
880 .name = "reset_stats",
881 .write_u64 = blkiocg_reset_stats,
882 },
883 #ifdef CONFIG_DEBUG_BLK_CGROUP
884 {
885 .name = "avg_queue_size",
886 .read_map = blkiocg_avg_queue_size_read,
887 },
888 {
889 .name = "group_wait_time",
890 .read_map = blkiocg_group_wait_time_read,
891 },
892 {
893 .name = "idle_time",
894 .read_map = blkiocg_idle_time_read,
895 },
896 {
897 .name = "empty_time",
898 .read_map = blkiocg_empty_time_read,
899 },
900 {
901 .name = "dequeue",
902 .read_map = blkiocg_dequeue_read,
903 },
904 #endif
905 };
906
907 static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
908 {
909 return cgroup_add_files(cgroup, subsys, blkio_files,
910 ARRAY_SIZE(blkio_files));
911 }
912
913 static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
914 {
915 struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
916 unsigned long flags;
917 struct blkio_group *blkg;
918 void *key;
919 struct blkio_policy_type *blkiop;
920 struct blkio_policy_node *pn, *pntmp;
921
922 rcu_read_lock();
923 remove_entry:
924 spin_lock_irqsave(&blkcg->lock, flags);
925
926 if (hlist_empty(&blkcg->blkg_list)) {
927 spin_unlock_irqrestore(&blkcg->lock, flags);
928 goto done;
929 }
930
931 blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
932 blkcg_node);
933 key = rcu_dereference(blkg->key);
934 __blkiocg_del_blkio_group(blkg);
935
936 spin_unlock_irqrestore(&blkcg->lock, flags);
937
938 /*
939 * This blkio_group is being unlinked as associated cgroup is going
940 * away. Let all the IO controlling policies know about this event.
941 *
942 * Currently this is static call to one io controlling policy. Once
943 * we have more policies in place, we need some dynamic registration
944 * of callback function.
945 */
946 spin_lock(&blkio_list_lock);
947 list_for_each_entry(blkiop, &blkio_list, list)
948 blkiop->ops.blkio_unlink_group_fn(key, blkg);
949 spin_unlock(&blkio_list_lock);
950 goto remove_entry;
951
952 done:
953 list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
954 blkio_policy_delete_node(pn);
955 kfree(pn);
956 }
957 free_css_id(&blkio_subsys, &blkcg->css);
958 rcu_read_unlock();
959 if (blkcg != &blkio_root_cgroup)
960 kfree(blkcg);
961 }
962
963 static struct cgroup_subsys_state *
964 blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
965 {
966 struct blkio_cgroup *blkcg, *parent_blkcg;
967
968 if (!cgroup->parent) {
969 blkcg = &blkio_root_cgroup;
970 goto done;
971 }
972
973 /* Currently we do not support hierarchy deeper than two level (0,1) */
974 parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent);
975 if (css_depth(&parent_blkcg->css) > 0)
976 return ERR_PTR(-EINVAL);
977
978 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
979 if (!blkcg)
980 return ERR_PTR(-ENOMEM);
981
982 blkcg->weight = BLKIO_WEIGHT_DEFAULT;
983 done:
984 spin_lock_init(&blkcg->lock);
985 INIT_HLIST_HEAD(&blkcg->blkg_list);
986
987 INIT_LIST_HEAD(&blkcg->policy_list);
988 return &blkcg->css;
989 }
990
991 /*
992 * We cannot support shared io contexts, as we have no mean to support
993 * two tasks with the same ioc in two different groups without major rework
994 * of the main cic data structures. For now we allow a task to change
995 * its cgroup only if it's the only owner of its ioc.
996 */
997 static int blkiocg_can_attach(struct cgroup_subsys *subsys,
998 struct cgroup *cgroup, struct task_struct *tsk,
999 bool threadgroup)
1000 {
1001 struct io_context *ioc;
1002 int ret = 0;
1003
1004 /* task_lock() is needed to avoid races with exit_io_context() */
1005 task_lock(tsk);
1006 ioc = tsk->io_context;
1007 if (ioc && atomic_read(&ioc->nr_tasks) > 1)
1008 ret = -EINVAL;
1009 task_unlock(tsk);
1010
1011 return ret;
1012 }
1013
1014 static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup,
1015 struct cgroup *prev, struct task_struct *tsk,
1016 bool threadgroup)
1017 {
1018 struct io_context *ioc;
1019
1020 task_lock(tsk);
1021 ioc = tsk->io_context;
1022 if (ioc)
1023 ioc->cgroup_changed = 1;
1024 task_unlock(tsk);
1025 }
1026
1027 void blkio_policy_register(struct blkio_policy_type *blkiop)
1028 {
1029 spin_lock(&blkio_list_lock);
1030 list_add_tail(&blkiop->list, &blkio_list);
1031 spin_unlock(&blkio_list_lock);
1032 }
1033 EXPORT_SYMBOL_GPL(blkio_policy_register);
1034
1035 void blkio_policy_unregister(struct blkio_policy_type *blkiop)
1036 {
1037 spin_lock(&blkio_list_lock);
1038 list_del_init(&blkiop->list);
1039 spin_unlock(&blkio_list_lock);
1040 }
1041 EXPORT_SYMBOL_GPL(blkio_policy_unregister);
1042
1043 static int __init init_cgroup_blkio(void)
1044 {
1045 return cgroup_load_subsys(&blkio_subsys);
1046 }
1047
1048 static void __exit exit_cgroup_blkio(void)
1049 {
1050 cgroup_unload_subsys(&blkio_subsys);
1051 }
1052
1053 module_init(init_cgroup_blkio);
1054 module_exit(exit_cgroup_blkio);
1055 MODULE_LICENSE("GPL");
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