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3dcf60bc | 1 | // SPDX-License-Identifier: GPL-2.0 |
31e4c28d VG |
2 | /* |
3 | * Common Block IO controller cgroup interface | |
4 | * | |
5 | * Based on ideas and code from CFQ, CFS and BFQ: | |
6 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> | |
7 | * | |
8 | * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> | |
9 | * Paolo Valente <paolo.valente@unimore.it> | |
10 | * | |
11 | * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> | |
12 | * Nauman Rafique <nauman@google.com> | |
e48453c3 AA |
13 | * |
14 | * For policy-specific per-blkcg data: | |
15 | * Copyright (C) 2015 Paolo Valente <paolo.valente@unimore.it> | |
16 | * Arianna Avanzini <avanzini.arianna@gmail.com> | |
31e4c28d VG |
17 | */ |
18 | #include <linux/ioprio.h> | |
22084190 | 19 | #include <linux/kdev_t.h> |
9d6a986c | 20 | #include <linux/module.h> |
174cd4b1 | 21 | #include <linux/sched/signal.h> |
accee785 | 22 | #include <linux/err.h> |
9195291e | 23 | #include <linux/blkdev.h> |
52ebea74 | 24 | #include <linux/backing-dev.h> |
5a0e3ad6 | 25 | #include <linux/slab.h> |
34d0f179 | 26 | #include <linux/genhd.h> |
72e06c25 | 27 | #include <linux/delay.h> |
9a9e8a26 | 28 | #include <linux/atomic.h> |
36aa9e5f | 29 | #include <linux/ctype.h> |
eea8f41c | 30 | #include <linux/blk-cgroup.h> |
d09d8df3 | 31 | #include <linux/tracehook.h> |
fd112c74 | 32 | #include <linux/psi.h> |
5efd6113 | 33 | #include "blk.h" |
3e252066 | 34 | |
84c124da DS |
35 | #define MAX_KEY_LEN 100 |
36 | ||
838f13bf TH |
37 | /* |
38 | * blkcg_pol_mutex protects blkcg_policy[] and policy [de]activation. | |
39 | * blkcg_pol_register_mutex nests outside of it and synchronizes entire | |
40 | * policy [un]register operations including cgroup file additions / | |
41 | * removals. Putting cgroup file registration outside blkcg_pol_mutex | |
42 | * allows grabbing it from cgroup callbacks. | |
43 | */ | |
44 | static DEFINE_MUTEX(blkcg_pol_register_mutex); | |
bc0d6501 | 45 | static DEFINE_MUTEX(blkcg_pol_mutex); |
923adde1 | 46 | |
e48453c3 | 47 | struct blkcg blkcg_root; |
3c798398 | 48 | EXPORT_SYMBOL_GPL(blkcg_root); |
9d6a986c | 49 | |
496d5e75 | 50 | struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css; |
9b0eb69b | 51 | EXPORT_SYMBOL_GPL(blkcg_root_css); |
496d5e75 | 52 | |
3c798398 | 53 | static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS]; |
035d10b2 | 54 | |
7876f930 TH |
55 | static LIST_HEAD(all_blkcgs); /* protected by blkcg_pol_mutex */ |
56 | ||
07b0fdec | 57 | bool blkcg_debug_stats = false; |
d3f77dfd | 58 | static struct workqueue_struct *blkcg_punt_bio_wq; |
903d23f0 | 59 | |
a2b1693b | 60 | static bool blkcg_policy_enabled(struct request_queue *q, |
3c798398 | 61 | const struct blkcg_policy *pol) |
a2b1693b TH |
62 | { |
63 | return pol && test_bit(pol->plid, q->blkcg_pols); | |
64 | } | |
65 | ||
0381411e TH |
66 | /** |
67 | * blkg_free - free a blkg | |
68 | * @blkg: blkg to free | |
69 | * | |
70 | * Free @blkg which may be partially allocated. | |
71 | */ | |
3c798398 | 72 | static void blkg_free(struct blkcg_gq *blkg) |
0381411e | 73 | { |
e8989fae | 74 | int i; |
549d3aa8 TH |
75 | |
76 | if (!blkg) | |
77 | return; | |
78 | ||
db613670 | 79 | for (i = 0; i < BLKCG_MAX_POLS; i++) |
001bea73 TH |
80 | if (blkg->pd[i]) |
81 | blkcg_policy[i]->pd_free_fn(blkg->pd[i]); | |
e8989fae | 82 | |
f7331648 | 83 | free_percpu(blkg->iostat_cpu); |
ef069b97 | 84 | percpu_ref_exit(&blkg->refcnt); |
549d3aa8 | 85 | kfree(blkg); |
0381411e TH |
86 | } |
87 | ||
7fcf2b03 DZ |
88 | static void __blkg_release(struct rcu_head *rcu) |
89 | { | |
90 | struct blkcg_gq *blkg = container_of(rcu, struct blkcg_gq, rcu_head); | |
91 | ||
d3f77dfd TH |
92 | WARN_ON(!bio_list_empty(&blkg->async_bios)); |
93 | ||
7fcf2b03 DZ |
94 | /* release the blkcg and parent blkg refs this blkg has been holding */ |
95 | css_put(&blkg->blkcg->css); | |
96 | if (blkg->parent) | |
97 | blkg_put(blkg->parent); | |
7fcf2b03 DZ |
98 | blkg_free(blkg); |
99 | } | |
100 | ||
101 | /* | |
102 | * A group is RCU protected, but having an rcu lock does not mean that one | |
103 | * can access all the fields of blkg and assume these are valid. For | |
104 | * example, don't try to follow throtl_data and request queue links. | |
105 | * | |
106 | * Having a reference to blkg under an rcu allows accesses to only values | |
107 | * local to groups like group stats and group rate limits. | |
108 | */ | |
109 | static void blkg_release(struct percpu_ref *ref) | |
110 | { | |
111 | struct blkcg_gq *blkg = container_of(ref, struct blkcg_gq, refcnt); | |
112 | ||
113 | call_rcu(&blkg->rcu_head, __blkg_release); | |
114 | } | |
115 | ||
d3f77dfd TH |
116 | static void blkg_async_bio_workfn(struct work_struct *work) |
117 | { | |
118 | struct blkcg_gq *blkg = container_of(work, struct blkcg_gq, | |
119 | async_bio_work); | |
120 | struct bio_list bios = BIO_EMPTY_LIST; | |
121 | struct bio *bio; | |
192f1c6b XT |
122 | struct blk_plug plug; |
123 | bool need_plug = false; | |
d3f77dfd TH |
124 | |
125 | /* as long as there are pending bios, @blkg can't go away */ | |
126 | spin_lock_bh(&blkg->async_bio_lock); | |
127 | bio_list_merge(&bios, &blkg->async_bios); | |
128 | bio_list_init(&blkg->async_bios); | |
129 | spin_unlock_bh(&blkg->async_bio_lock); | |
130 | ||
192f1c6b XT |
131 | /* start plug only when bio_list contains at least 2 bios */ |
132 | if (bios.head && bios.head->bi_next) { | |
133 | need_plug = true; | |
134 | blk_start_plug(&plug); | |
135 | } | |
d3f77dfd TH |
136 | while ((bio = bio_list_pop(&bios))) |
137 | submit_bio(bio); | |
192f1c6b XT |
138 | if (need_plug) |
139 | blk_finish_plug(&plug); | |
d3f77dfd TH |
140 | } |
141 | ||
0381411e TH |
142 | /** |
143 | * blkg_alloc - allocate a blkg | |
144 | * @blkcg: block cgroup the new blkg is associated with | |
145 | * @q: request_queue the new blkg is associated with | |
15974993 | 146 | * @gfp_mask: allocation mask to use |
0381411e | 147 | * |
e8989fae | 148 | * Allocate a new blkg assocating @blkcg and @q. |
0381411e | 149 | */ |
15974993 TH |
150 | static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q, |
151 | gfp_t gfp_mask) | |
0381411e | 152 | { |
3c798398 | 153 | struct blkcg_gq *blkg; |
f7331648 | 154 | int i, cpu; |
0381411e TH |
155 | |
156 | /* alloc and init base part */ | |
15974993 | 157 | blkg = kzalloc_node(sizeof(*blkg), gfp_mask, q->node); |
0381411e TH |
158 | if (!blkg) |
159 | return NULL; | |
160 | ||
ef069b97 TH |
161 | if (percpu_ref_init(&blkg->refcnt, blkg_release, 0, gfp_mask)) |
162 | goto err_free; | |
163 | ||
f7331648 TH |
164 | blkg->iostat_cpu = alloc_percpu_gfp(struct blkg_iostat_set, gfp_mask); |
165 | if (!blkg->iostat_cpu) | |
77ea7338 TH |
166 | goto err_free; |
167 | ||
c875f4d0 | 168 | blkg->q = q; |
e8989fae | 169 | INIT_LIST_HEAD(&blkg->q_node); |
d3f77dfd TH |
170 | spin_lock_init(&blkg->async_bio_lock); |
171 | bio_list_init(&blkg->async_bios); | |
172 | INIT_WORK(&blkg->async_bio_work, blkg_async_bio_workfn); | |
0381411e | 173 | blkg->blkcg = blkcg; |
0381411e | 174 | |
f7331648 TH |
175 | u64_stats_init(&blkg->iostat.sync); |
176 | for_each_possible_cpu(cpu) | |
177 | u64_stats_init(&per_cpu_ptr(blkg->iostat_cpu, cpu)->sync); | |
178 | ||
8bd435b3 | 179 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
3c798398 | 180 | struct blkcg_policy *pol = blkcg_policy[i]; |
e8989fae | 181 | struct blkg_policy_data *pd; |
0381411e | 182 | |
a2b1693b | 183 | if (!blkcg_policy_enabled(q, pol)) |
e8989fae TH |
184 | continue; |
185 | ||
186 | /* alloc per-policy data and attach it to blkg */ | |
cf09a8ee | 187 | pd = pol->pd_alloc_fn(gfp_mask, q, blkcg); |
a051661c TH |
188 | if (!pd) |
189 | goto err_free; | |
549d3aa8 | 190 | |
e8989fae TH |
191 | blkg->pd[i] = pd; |
192 | pd->blkg = blkg; | |
b276a876 | 193 | pd->plid = i; |
e8989fae TH |
194 | } |
195 | ||
0381411e | 196 | return blkg; |
a051661c TH |
197 | |
198 | err_free: | |
199 | blkg_free(blkg); | |
200 | return NULL; | |
0381411e TH |
201 | } |
202 | ||
24f29046 TH |
203 | struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg, |
204 | struct request_queue *q, bool update_hint) | |
80fd9979 | 205 | { |
3c798398 | 206 | struct blkcg_gq *blkg; |
80fd9979 | 207 | |
a637120e | 208 | /* |
86cde6b6 TH |
209 | * Hint didn't match. Look up from the radix tree. Note that the |
210 | * hint can only be updated under queue_lock as otherwise @blkg | |
211 | * could have already been removed from blkg_tree. The caller is | |
212 | * responsible for grabbing queue_lock if @update_hint. | |
a637120e TH |
213 | */ |
214 | blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id); | |
86cde6b6 TH |
215 | if (blkg && blkg->q == q) { |
216 | if (update_hint) { | |
0d945c1f | 217 | lockdep_assert_held(&q->queue_lock); |
86cde6b6 TH |
218 | rcu_assign_pointer(blkcg->blkg_hint, blkg); |
219 | } | |
a637120e | 220 | return blkg; |
86cde6b6 | 221 | } |
a637120e | 222 | |
80fd9979 TH |
223 | return NULL; |
224 | } | |
ae118896 | 225 | EXPORT_SYMBOL_GPL(blkg_lookup_slowpath); |
80fd9979 | 226 | |
15974993 | 227 | /* |
d708f0d5 JA |
228 | * If @new_blkg is %NULL, this function tries to allocate a new one as |
229 | * necessary using %GFP_NOWAIT. @new_blkg is always consumed on return. | |
15974993 | 230 | */ |
86cde6b6 | 231 | static struct blkcg_gq *blkg_create(struct blkcg *blkcg, |
d708f0d5 JA |
232 | struct request_queue *q, |
233 | struct blkcg_gq *new_blkg) | |
5624a4e4 | 234 | { |
d708f0d5 | 235 | struct blkcg_gq *blkg; |
f427d909 | 236 | int i, ret; |
5624a4e4 | 237 | |
cd1604fa | 238 | WARN_ON_ONCE(!rcu_read_lock_held()); |
0d945c1f | 239 | lockdep_assert_held(&q->queue_lock); |
cd1604fa | 240 | |
0273ac34 DZ |
241 | /* request_queue is dying, do not create/recreate a blkg */ |
242 | if (blk_queue_dying(q)) { | |
243 | ret = -ENODEV; | |
244 | goto err_free_blkg; | |
245 | } | |
246 | ||
7ee9c562 | 247 | /* blkg holds a reference to blkcg */ |
ec903c0c | 248 | if (!css_tryget_online(&blkcg->css)) { |
20386ce0 | 249 | ret = -ENODEV; |
93e6d5d8 | 250 | goto err_free_blkg; |
15974993 | 251 | } |
cd1604fa | 252 | |
d708f0d5 JA |
253 | /* allocate */ |
254 | if (!new_blkg) { | |
255 | new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN); | |
256 | if (unlikely(!new_blkg)) { | |
257 | ret = -ENOMEM; | |
8c911f3d | 258 | goto err_put_css; |
15974993 TH |
259 | } |
260 | } | |
d708f0d5 | 261 | blkg = new_blkg; |
cd1604fa | 262 | |
db613670 | 263 | /* link parent */ |
3c547865 TH |
264 | if (blkcg_parent(blkcg)) { |
265 | blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false); | |
266 | if (WARN_ON_ONCE(!blkg->parent)) { | |
20386ce0 | 267 | ret = -ENODEV; |
8c911f3d | 268 | goto err_put_css; |
3c547865 TH |
269 | } |
270 | blkg_get(blkg->parent); | |
271 | } | |
272 | ||
db613670 TH |
273 | /* invoke per-policy init */ |
274 | for (i = 0; i < BLKCG_MAX_POLS; i++) { | |
275 | struct blkcg_policy *pol = blkcg_policy[i]; | |
276 | ||
277 | if (blkg->pd[i] && pol->pd_init_fn) | |
a9520cd6 | 278 | pol->pd_init_fn(blkg->pd[i]); |
db613670 TH |
279 | } |
280 | ||
281 | /* insert */ | |
cd1604fa | 282 | spin_lock(&blkcg->lock); |
a637120e TH |
283 | ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg); |
284 | if (likely(!ret)) { | |
285 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); | |
286 | list_add(&blkg->q_node, &q->blkg_list); | |
f427d909 TH |
287 | |
288 | for (i = 0; i < BLKCG_MAX_POLS; i++) { | |
289 | struct blkcg_policy *pol = blkcg_policy[i]; | |
290 | ||
291 | if (blkg->pd[i] && pol->pd_online_fn) | |
a9520cd6 | 292 | pol->pd_online_fn(blkg->pd[i]); |
f427d909 | 293 | } |
a637120e | 294 | } |
f427d909 | 295 | blkg->online = true; |
cd1604fa | 296 | spin_unlock(&blkcg->lock); |
496fb780 | 297 | |
ec13b1d6 | 298 | if (!ret) |
a637120e | 299 | return blkg; |
15974993 | 300 | |
3c547865 TH |
301 | /* @blkg failed fully initialized, use the usual release path */ |
302 | blkg_put(blkg); | |
303 | return ERR_PTR(ret); | |
304 | ||
d708f0d5 | 305 | err_put_css: |
496fb780 | 306 | css_put(&blkcg->css); |
93e6d5d8 | 307 | err_free_blkg: |
d708f0d5 | 308 | blkg_free(new_blkg); |
93e6d5d8 | 309 | return ERR_PTR(ret); |
31e4c28d | 310 | } |
3c96cb32 | 311 | |
86cde6b6 | 312 | /** |
8c546287 | 313 | * blkg_lookup_create - lookup blkg, try to create one if not there |
86cde6b6 TH |
314 | * @blkcg: blkcg of interest |
315 | * @q: request_queue of interest | |
316 | * | |
317 | * Lookup blkg for the @blkcg - @q pair. If it doesn't exist, try to | |
3c547865 TH |
318 | * create one. blkg creation is performed recursively from blkcg_root such |
319 | * that all non-root blkg's have access to the parent blkg. This function | |
8c546287 | 320 | * should be called under RCU read lock and takes @q->queue_lock. |
86cde6b6 | 321 | * |
beea9da0 DZ |
322 | * Returns the blkg or the closest blkg if blkg_create() fails as it walks |
323 | * down from root. | |
86cde6b6 | 324 | */ |
8c546287 CH |
325 | static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, |
326 | struct request_queue *q) | |
3c96cb32 | 327 | { |
86cde6b6 | 328 | struct blkcg_gq *blkg; |
8c546287 | 329 | unsigned long flags; |
86cde6b6 TH |
330 | |
331 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
86cde6b6 | 332 | |
8c546287 | 333 | blkg = blkg_lookup(blkcg, q); |
86cde6b6 TH |
334 | if (blkg) |
335 | return blkg; | |
336 | ||
8c546287 CH |
337 | spin_lock_irqsave(&q->queue_lock, flags); |
338 | blkg = __blkg_lookup(blkcg, q, true); | |
339 | if (blkg) | |
340 | goto found; | |
341 | ||
3c547865 TH |
342 | /* |
343 | * Create blkgs walking down from blkcg_root to @blkcg, so that all | |
beea9da0 DZ |
344 | * non-root blkgs have access to their parents. Returns the closest |
345 | * blkg to the intended blkg should blkg_create() fail. | |
3c547865 TH |
346 | */ |
347 | while (true) { | |
348 | struct blkcg *pos = blkcg; | |
349 | struct blkcg *parent = blkcg_parent(blkcg); | |
beea9da0 DZ |
350 | struct blkcg_gq *ret_blkg = q->root_blkg; |
351 | ||
352 | while (parent) { | |
353 | blkg = __blkg_lookup(parent, q, false); | |
354 | if (blkg) { | |
355 | /* remember closest blkg */ | |
356 | ret_blkg = blkg; | |
357 | break; | |
358 | } | |
3c547865 TH |
359 | pos = parent; |
360 | parent = blkcg_parent(parent); | |
361 | } | |
362 | ||
d708f0d5 | 363 | blkg = blkg_create(pos, q, NULL); |
8c546287 CH |
364 | if (IS_ERR(blkg)) { |
365 | blkg = ret_blkg; | |
366 | break; | |
367 | } | |
beea9da0 | 368 | if (pos == blkcg) |
8c546287 | 369 | break; |
b978962a DZ |
370 | } |
371 | ||
8c546287 CH |
372 | found: |
373 | spin_unlock_irqrestore(&q->queue_lock, flags); | |
b978962a DZ |
374 | return blkg; |
375 | } | |
376 | ||
3c798398 | 377 | static void blkg_destroy(struct blkcg_gq *blkg) |
03aa264a | 378 | { |
3c798398 | 379 | struct blkcg *blkcg = blkg->blkcg; |
6b065462 | 380 | int i; |
03aa264a | 381 | |
0d945c1f | 382 | lockdep_assert_held(&blkg->q->queue_lock); |
9f13ef67 | 383 | lockdep_assert_held(&blkcg->lock); |
03aa264a TH |
384 | |
385 | /* Something wrong if we are trying to remove same group twice */ | |
e8989fae | 386 | WARN_ON_ONCE(list_empty(&blkg->q_node)); |
9f13ef67 | 387 | WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node)); |
a637120e | 388 | |
6b065462 DZF |
389 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
390 | struct blkcg_policy *pol = blkcg_policy[i]; | |
391 | ||
392 | if (blkg->pd[i] && pol->pd_offline_fn) | |
393 | pol->pd_offline_fn(blkg->pd[i]); | |
394 | } | |
395 | ||
f427d909 TH |
396 | blkg->online = false; |
397 | ||
a637120e | 398 | radix_tree_delete(&blkcg->blkg_tree, blkg->q->id); |
e8989fae | 399 | list_del_init(&blkg->q_node); |
9f13ef67 | 400 | hlist_del_init_rcu(&blkg->blkcg_node); |
03aa264a | 401 | |
a637120e TH |
402 | /* |
403 | * Both setting lookup hint to and clearing it from @blkg are done | |
404 | * under queue_lock. If it's not pointing to @blkg now, it never | |
405 | * will. Hint assignment itself can race safely. | |
406 | */ | |
ec6c676a | 407 | if (rcu_access_pointer(blkcg->blkg_hint) == blkg) |
a637120e TH |
408 | rcu_assign_pointer(blkcg->blkg_hint, NULL); |
409 | ||
03aa264a TH |
410 | /* |
411 | * Put the reference taken at the time of creation so that when all | |
412 | * queues are gone, group can be destroyed. | |
413 | */ | |
7fcf2b03 | 414 | percpu_ref_kill(&blkg->refcnt); |
03aa264a TH |
415 | } |
416 | ||
9f13ef67 TH |
417 | /** |
418 | * blkg_destroy_all - destroy all blkgs associated with a request_queue | |
419 | * @q: request_queue of interest | |
9f13ef67 | 420 | * |
3c96cb32 | 421 | * Destroy all blkgs associated with @q. |
9f13ef67 | 422 | */ |
3c96cb32 | 423 | static void blkg_destroy_all(struct request_queue *q) |
72e06c25 | 424 | { |
3c798398 | 425 | struct blkcg_gq *blkg, *n; |
72e06c25 | 426 | |
0d945c1f | 427 | spin_lock_irq(&q->queue_lock); |
9f13ef67 | 428 | list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) { |
3c798398 | 429 | struct blkcg *blkcg = blkg->blkcg; |
72e06c25 | 430 | |
9f13ef67 TH |
431 | spin_lock(&blkcg->lock); |
432 | blkg_destroy(blkg); | |
433 | spin_unlock(&blkcg->lock); | |
72e06c25 | 434 | } |
6fe810bd TH |
435 | |
436 | q->root_blkg = NULL; | |
0d945c1f | 437 | spin_unlock_irq(&q->queue_lock); |
72e06c25 TH |
438 | } |
439 | ||
182446d0 TH |
440 | static int blkcg_reset_stats(struct cgroup_subsys_state *css, |
441 | struct cftype *cftype, u64 val) | |
303a3acb | 442 | { |
182446d0 | 443 | struct blkcg *blkcg = css_to_blkcg(css); |
3c798398 | 444 | struct blkcg_gq *blkg; |
f7331648 | 445 | int i, cpu; |
303a3acb | 446 | |
838f13bf | 447 | mutex_lock(&blkcg_pol_mutex); |
303a3acb | 448 | spin_lock_irq(&blkcg->lock); |
997a026c TH |
449 | |
450 | /* | |
451 | * Note that stat reset is racy - it doesn't synchronize against | |
452 | * stat updates. This is a debug feature which shouldn't exist | |
453 | * anyway. If you get hit by a race, retry. | |
454 | */ | |
b67bfe0d | 455 | hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { |
f7331648 TH |
456 | for_each_possible_cpu(cpu) { |
457 | struct blkg_iostat_set *bis = | |
458 | per_cpu_ptr(blkg->iostat_cpu, cpu); | |
459 | memset(bis, 0, sizeof(*bis)); | |
460 | } | |
461 | memset(&blkg->iostat, 0, sizeof(blkg->iostat)); | |
77ea7338 | 462 | |
8bd435b3 | 463 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
3c798398 | 464 | struct blkcg_policy *pol = blkcg_policy[i]; |
549d3aa8 | 465 | |
a9520cd6 TH |
466 | if (blkg->pd[i] && pol->pd_reset_stats_fn) |
467 | pol->pd_reset_stats_fn(blkg->pd[i]); | |
bc0d6501 | 468 | } |
303a3acb | 469 | } |
f0bdc8cd | 470 | |
303a3acb | 471 | spin_unlock_irq(&blkcg->lock); |
bc0d6501 | 472 | mutex_unlock(&blkcg_pol_mutex); |
303a3acb DS |
473 | return 0; |
474 | } | |
475 | ||
dd165eb3 | 476 | const char *blkg_dev_name(struct blkcg_gq *blkg) |
303a3acb | 477 | { |
d3d32e69 | 478 | /* some drivers (floppy) instantiate a queue w/o disk registered */ |
dc3b17cc | 479 | if (blkg->q->backing_dev_info->dev) |
d51cfc53 | 480 | return bdi_dev_name(blkg->q->backing_dev_info); |
d3d32e69 | 481 | return NULL; |
303a3acb DS |
482 | } |
483 | ||
d3d32e69 TH |
484 | /** |
485 | * blkcg_print_blkgs - helper for printing per-blkg data | |
486 | * @sf: seq_file to print to | |
487 | * @blkcg: blkcg of interest | |
488 | * @prfill: fill function to print out a blkg | |
489 | * @pol: policy in question | |
490 | * @data: data to be passed to @prfill | |
491 | * @show_total: to print out sum of prfill return values or not | |
492 | * | |
493 | * This function invokes @prfill on each blkg of @blkcg if pd for the | |
494 | * policy specified by @pol exists. @prfill is invoked with @sf, the | |
810ecfa7 TH |
495 | * policy data and @data and the matching queue lock held. If @show_total |
496 | * is %true, the sum of the return values from @prfill is printed with | |
497 | * "Total" label at the end. | |
d3d32e69 TH |
498 | * |
499 | * This is to be used to construct print functions for | |
500 | * cftype->read_seq_string method. | |
501 | */ | |
3c798398 | 502 | void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, |
f95a04af TH |
503 | u64 (*prfill)(struct seq_file *, |
504 | struct blkg_policy_data *, int), | |
3c798398 | 505 | const struct blkcg_policy *pol, int data, |
ec399347 | 506 | bool show_total) |
5624a4e4 | 507 | { |
3c798398 | 508 | struct blkcg_gq *blkg; |
d3d32e69 | 509 | u64 total = 0; |
5624a4e4 | 510 | |
810ecfa7 | 511 | rcu_read_lock(); |
ee89f812 | 512 | hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { |
0d945c1f | 513 | spin_lock_irq(&blkg->q->queue_lock); |
a2b1693b | 514 | if (blkcg_policy_enabled(blkg->q, pol)) |
f95a04af | 515 | total += prfill(sf, blkg->pd[pol->plid], data); |
0d945c1f | 516 | spin_unlock_irq(&blkg->q->queue_lock); |
810ecfa7 TH |
517 | } |
518 | rcu_read_unlock(); | |
d3d32e69 TH |
519 | |
520 | if (show_total) | |
521 | seq_printf(sf, "Total %llu\n", (unsigned long long)total); | |
522 | } | |
829fdb50 | 523 | EXPORT_SYMBOL_GPL(blkcg_print_blkgs); |
d3d32e69 TH |
524 | |
525 | /** | |
526 | * __blkg_prfill_u64 - prfill helper for a single u64 value | |
527 | * @sf: seq_file to print to | |
f95a04af | 528 | * @pd: policy private data of interest |
d3d32e69 TH |
529 | * @v: value to print |
530 | * | |
f95a04af | 531 | * Print @v to @sf for the device assocaited with @pd. |
d3d32e69 | 532 | */ |
f95a04af | 533 | u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v) |
d3d32e69 | 534 | { |
f95a04af | 535 | const char *dname = blkg_dev_name(pd->blkg); |
d3d32e69 TH |
536 | |
537 | if (!dname) | |
538 | return 0; | |
539 | ||
540 | seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v); | |
541 | return v; | |
542 | } | |
829fdb50 | 543 | EXPORT_SYMBOL_GPL(__blkg_prfill_u64); |
d3d32e69 | 544 | |
457e490f TE |
545 | /* Performs queue bypass and policy enabled checks then looks up blkg. */ |
546 | static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg, | |
547 | const struct blkcg_policy *pol, | |
548 | struct request_queue *q) | |
549 | { | |
550 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
0d945c1f | 551 | lockdep_assert_held(&q->queue_lock); |
457e490f TE |
552 | |
553 | if (!blkcg_policy_enabled(q, pol)) | |
554 | return ERR_PTR(-EOPNOTSUPP); | |
457e490f TE |
555 | return __blkg_lookup(blkcg, q, true /* update_hint */); |
556 | } | |
557 | ||
015d254c TH |
558 | /** |
559 | * blkg_conf_prep - parse and prepare for per-blkg config update | |
560 | * @inputp: input string pointer | |
561 | * | |
562 | * Parse the device node prefix part, MAJ:MIN, of per-blkg config update | |
563 | * from @input and get and return the matching gendisk. *@inputp is | |
564 | * updated to point past the device node prefix. Returns an ERR_PTR() | |
565 | * value on error. | |
566 | * | |
567 | * Use this function iff blkg_conf_prep() can't be used for some reason. | |
568 | */ | |
569 | struct gendisk *blkcg_conf_get_disk(char **inputp) | |
570 | { | |
571 | char *input = *inputp; | |
572 | unsigned int major, minor; | |
573 | struct gendisk *disk; | |
574 | int key_len, part; | |
575 | ||
576 | if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2) | |
577 | return ERR_PTR(-EINVAL); | |
578 | ||
579 | input += key_len; | |
580 | if (!isspace(*input)) | |
581 | return ERR_PTR(-EINVAL); | |
582 | input = skip_spaces(input); | |
583 | ||
584 | disk = get_gendisk(MKDEV(major, minor), &part); | |
585 | if (!disk) | |
586 | return ERR_PTR(-ENODEV); | |
587 | if (part) { | |
588 | put_disk_and_module(disk); | |
589 | return ERR_PTR(-ENODEV); | |
590 | } | |
591 | ||
592 | *inputp = input; | |
593 | return disk; | |
594 | } | |
595 | ||
3a8b31d3 TH |
596 | /** |
597 | * blkg_conf_prep - parse and prepare for per-blkg config update | |
598 | * @blkcg: target block cgroup | |
da8b0662 | 599 | * @pol: target policy |
3a8b31d3 TH |
600 | * @input: input string |
601 | * @ctx: blkg_conf_ctx to be filled | |
602 | * | |
603 | * Parse per-blkg config update from @input and initialize @ctx with the | |
36aa9e5f TH |
604 | * result. @ctx->blkg points to the blkg to be updated and @ctx->body the |
605 | * part of @input following MAJ:MIN. This function returns with RCU read | |
606 | * lock and queue lock held and must be paired with blkg_conf_finish(). | |
3a8b31d3 | 607 | */ |
3c798398 | 608 | int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, |
36aa9e5f | 609 | char *input, struct blkg_conf_ctx *ctx) |
0d945c1f | 610 | __acquires(rcu) __acquires(&disk->queue->queue_lock) |
34d0f179 | 611 | { |
3a8b31d3 | 612 | struct gendisk *disk; |
457e490f | 613 | struct request_queue *q; |
3c798398 | 614 | struct blkcg_gq *blkg; |
015d254c | 615 | int ret; |
36aa9e5f | 616 | |
015d254c TH |
617 | disk = blkcg_conf_get_disk(&input); |
618 | if (IS_ERR(disk)) | |
619 | return PTR_ERR(disk); | |
e56da7e2 | 620 | |
457e490f | 621 | q = disk->queue; |
da8b0662 | 622 | |
457e490f | 623 | rcu_read_lock(); |
0d945c1f | 624 | spin_lock_irq(&q->queue_lock); |
e56da7e2 | 625 | |
457e490f | 626 | blkg = blkg_lookup_check(blkcg, pol, q); |
4bfd482e TH |
627 | if (IS_ERR(blkg)) { |
628 | ret = PTR_ERR(blkg); | |
457e490f TE |
629 | goto fail_unlock; |
630 | } | |
631 | ||
632 | if (blkg) | |
633 | goto success; | |
634 | ||
635 | /* | |
636 | * Create blkgs walking down from blkcg_root to @blkcg, so that all | |
637 | * non-root blkgs have access to their parents. | |
638 | */ | |
639 | while (true) { | |
640 | struct blkcg *pos = blkcg; | |
641 | struct blkcg *parent; | |
642 | struct blkcg_gq *new_blkg; | |
643 | ||
644 | parent = blkcg_parent(blkcg); | |
645 | while (parent && !__blkg_lookup(parent, q, false)) { | |
646 | pos = parent; | |
647 | parent = blkcg_parent(parent); | |
648 | } | |
649 | ||
650 | /* Drop locks to do new blkg allocation with GFP_KERNEL. */ | |
0d945c1f | 651 | spin_unlock_irq(&q->queue_lock); |
3a8b31d3 | 652 | rcu_read_unlock(); |
457e490f TE |
653 | |
654 | new_blkg = blkg_alloc(pos, q, GFP_KERNEL); | |
655 | if (unlikely(!new_blkg)) { | |
656 | ret = -ENOMEM; | |
657 | goto fail; | |
7702e8f4 | 658 | } |
3a8b31d3 | 659 | |
f255c19b GKB |
660 | if (radix_tree_preload(GFP_KERNEL)) { |
661 | blkg_free(new_blkg); | |
662 | ret = -ENOMEM; | |
663 | goto fail; | |
664 | } | |
665 | ||
457e490f | 666 | rcu_read_lock(); |
0d945c1f | 667 | spin_lock_irq(&q->queue_lock); |
457e490f TE |
668 | |
669 | blkg = blkg_lookup_check(pos, pol, q); | |
670 | if (IS_ERR(blkg)) { | |
671 | ret = PTR_ERR(blkg); | |
52abfcbd | 672 | blkg_free(new_blkg); |
f255c19b | 673 | goto fail_preloaded; |
457e490f TE |
674 | } |
675 | ||
676 | if (blkg) { | |
677 | blkg_free(new_blkg); | |
678 | } else { | |
679 | blkg = blkg_create(pos, q, new_blkg); | |
98d669b4 | 680 | if (IS_ERR(blkg)) { |
457e490f | 681 | ret = PTR_ERR(blkg); |
f255c19b | 682 | goto fail_preloaded; |
457e490f TE |
683 | } |
684 | } | |
685 | ||
f255c19b GKB |
686 | radix_tree_preload_end(); |
687 | ||
457e490f TE |
688 | if (pos == blkcg) |
689 | goto success; | |
690 | } | |
691 | success: | |
3a8b31d3 TH |
692 | ctx->disk = disk; |
693 | ctx->blkg = blkg; | |
015d254c | 694 | ctx->body = input; |
726fa694 | 695 | return 0; |
457e490f | 696 | |
f255c19b GKB |
697 | fail_preloaded: |
698 | radix_tree_preload_end(); | |
457e490f | 699 | fail_unlock: |
0d945c1f | 700 | spin_unlock_irq(&q->queue_lock); |
457e490f TE |
701 | rcu_read_unlock(); |
702 | fail: | |
9df6c299 | 703 | put_disk_and_module(disk); |
457e490f TE |
704 | /* |
705 | * If queue was bypassing, we should retry. Do so after a | |
706 | * short msleep(). It isn't strictly necessary but queue | |
707 | * can be bypassing for some time and it's always nice to | |
708 | * avoid busy looping. | |
709 | */ | |
710 | if (ret == -EBUSY) { | |
711 | msleep(10); | |
712 | ret = restart_syscall(); | |
713 | } | |
714 | return ret; | |
34d0f179 | 715 | } |
89f3b6d6 | 716 | EXPORT_SYMBOL_GPL(blkg_conf_prep); |
34d0f179 | 717 | |
3a8b31d3 TH |
718 | /** |
719 | * blkg_conf_finish - finish up per-blkg config update | |
720 | * @ctx: blkg_conf_ctx intiailized by blkg_conf_prep() | |
721 | * | |
722 | * Finish up after per-blkg config update. This function must be paired | |
723 | * with blkg_conf_prep(). | |
724 | */ | |
829fdb50 | 725 | void blkg_conf_finish(struct blkg_conf_ctx *ctx) |
0d945c1f | 726 | __releases(&ctx->disk->queue->queue_lock) __releases(rcu) |
34d0f179 | 727 | { |
0d945c1f | 728 | spin_unlock_irq(&ctx->disk->queue->queue_lock); |
3a8b31d3 | 729 | rcu_read_unlock(); |
9df6c299 | 730 | put_disk_and_module(ctx->disk); |
34d0f179 | 731 | } |
89f3b6d6 | 732 | EXPORT_SYMBOL_GPL(blkg_conf_finish); |
34d0f179 | 733 | |
cd1fc4b9 BB |
734 | static void blkg_iostat_set(struct blkg_iostat *dst, struct blkg_iostat *src) |
735 | { | |
736 | int i; | |
737 | ||
738 | for (i = 0; i < BLKG_IOSTAT_NR; i++) { | |
739 | dst->bytes[i] = src->bytes[i]; | |
740 | dst->ios[i] = src->ios[i]; | |
741 | } | |
742 | } | |
743 | ||
744 | static void blkg_iostat_add(struct blkg_iostat *dst, struct blkg_iostat *src) | |
745 | { | |
746 | int i; | |
747 | ||
748 | for (i = 0; i < BLKG_IOSTAT_NR; i++) { | |
749 | dst->bytes[i] += src->bytes[i]; | |
750 | dst->ios[i] += src->ios[i]; | |
751 | } | |
752 | } | |
753 | ||
754 | static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src) | |
755 | { | |
756 | int i; | |
757 | ||
758 | for (i = 0; i < BLKG_IOSTAT_NR; i++) { | |
759 | dst->bytes[i] -= src->bytes[i]; | |
760 | dst->ios[i] -= src->ios[i]; | |
761 | } | |
762 | } | |
763 | ||
764 | static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu) | |
765 | { | |
766 | struct blkcg *blkcg = css_to_blkcg(css); | |
767 | struct blkcg_gq *blkg; | |
768 | ||
769 | rcu_read_lock(); | |
770 | ||
771 | hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { | |
772 | struct blkcg_gq *parent = blkg->parent; | |
773 | struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu); | |
774 | struct blkg_iostat cur, delta; | |
775 | unsigned int seq; | |
776 | ||
777 | /* fetch the current per-cpu values */ | |
778 | do { | |
779 | seq = u64_stats_fetch_begin(&bisc->sync); | |
780 | blkg_iostat_set(&cur, &bisc->cur); | |
781 | } while (u64_stats_fetch_retry(&bisc->sync, seq)); | |
782 | ||
783 | /* propagate percpu delta to global */ | |
784 | u64_stats_update_begin(&blkg->iostat.sync); | |
785 | blkg_iostat_set(&delta, &cur); | |
786 | blkg_iostat_sub(&delta, &bisc->last); | |
787 | blkg_iostat_add(&blkg->iostat.cur, &delta); | |
788 | blkg_iostat_add(&bisc->last, &delta); | |
789 | u64_stats_update_end(&blkg->iostat.sync); | |
790 | ||
791 | /* propagate global delta to parent */ | |
792 | if (parent) { | |
793 | u64_stats_update_begin(&parent->iostat.sync); | |
794 | blkg_iostat_set(&delta, &blkg->iostat.cur); | |
795 | blkg_iostat_sub(&delta, &blkg->iostat.last); | |
796 | blkg_iostat_add(&parent->iostat.cur, &delta); | |
797 | blkg_iostat_add(&blkg->iostat.last, &delta); | |
798 | u64_stats_update_end(&parent->iostat.sync); | |
799 | } | |
800 | } | |
801 | ||
802 | rcu_read_unlock(); | |
803 | } | |
804 | ||
ef45fe47 BB |
805 | /* |
806 | * The rstat algorithms intentionally don't handle the root cgroup to avoid | |
807 | * incurring overhead when no cgroups are defined. For that reason, | |
808 | * cgroup_rstat_flush in blkcg_print_stat does not actually fill out the | |
809 | * iostat in the root cgroup's blkcg_gq. | |
810 | * | |
811 | * However, we would like to re-use the printing code between the root and | |
812 | * non-root cgroups to the extent possible. For that reason, we simulate | |
813 | * flushing the root cgroup's stats by explicitly filling in the iostat | |
814 | * with disk level statistics. | |
815 | */ | |
816 | static void blkcg_fill_root_iostats(void) | |
817 | { | |
818 | struct class_dev_iter iter; | |
819 | struct device *dev; | |
820 | ||
821 | class_dev_iter_init(&iter, &block_class, NULL, &disk_type); | |
822 | while ((dev = class_dev_iter_next(&iter))) { | |
823 | struct gendisk *disk = dev_to_disk(dev); | |
824 | struct hd_struct *part = disk_get_part(disk, 0); | |
825 | struct blkcg_gq *blkg = blk_queue_root_blkg(disk->queue); | |
826 | struct blkg_iostat tmp; | |
827 | int cpu; | |
828 | ||
829 | memset(&tmp, 0, sizeof(tmp)); | |
830 | for_each_possible_cpu(cpu) { | |
831 | struct disk_stats *cpu_dkstats; | |
832 | ||
833 | cpu_dkstats = per_cpu_ptr(part->dkstats, cpu); | |
834 | tmp.ios[BLKG_IOSTAT_READ] += | |
835 | cpu_dkstats->ios[STAT_READ]; | |
836 | tmp.ios[BLKG_IOSTAT_WRITE] += | |
837 | cpu_dkstats->ios[STAT_WRITE]; | |
838 | tmp.ios[BLKG_IOSTAT_DISCARD] += | |
839 | cpu_dkstats->ios[STAT_DISCARD]; | |
840 | // convert sectors to bytes | |
841 | tmp.bytes[BLKG_IOSTAT_READ] += | |
842 | cpu_dkstats->sectors[STAT_READ] << 9; | |
843 | tmp.bytes[BLKG_IOSTAT_WRITE] += | |
844 | cpu_dkstats->sectors[STAT_WRITE] << 9; | |
845 | tmp.bytes[BLKG_IOSTAT_DISCARD] += | |
846 | cpu_dkstats->sectors[STAT_DISCARD] << 9; | |
847 | ||
848 | u64_stats_update_begin(&blkg->iostat.sync); | |
849 | blkg_iostat_set(&blkg->iostat.cur, &tmp); | |
850 | u64_stats_update_end(&blkg->iostat.sync); | |
851 | } | |
852 | } | |
853 | } | |
854 | ||
2ee867dc TH |
855 | static int blkcg_print_stat(struct seq_file *sf, void *v) |
856 | { | |
857 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
858 | struct blkcg_gq *blkg; | |
859 | ||
ef45fe47 BB |
860 | if (!seq_css(sf)->parent) |
861 | blkcg_fill_root_iostats(); | |
862 | else | |
863 | cgroup_rstat_flush(blkcg->css.cgroup); | |
864 | ||
2ee867dc TH |
865 | rcu_read_lock(); |
866 | ||
867 | hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { | |
f7331648 | 868 | struct blkg_iostat_set *bis = &blkg->iostat; |
2ee867dc | 869 | const char *dname; |
903d23f0 | 870 | char *buf; |
636620b6 | 871 | u64 rbytes, wbytes, rios, wios, dbytes, dios; |
903d23f0 JB |
872 | size_t size = seq_get_buf(sf, &buf), off = 0; |
873 | int i; | |
874 | bool has_stats = false; | |
f7331648 | 875 | unsigned seq; |
2ee867dc | 876 | |
b0814361 TH |
877 | spin_lock_irq(&blkg->q->queue_lock); |
878 | ||
879 | if (!blkg->online) | |
880 | goto skip; | |
881 | ||
2ee867dc TH |
882 | dname = blkg_dev_name(blkg); |
883 | if (!dname) | |
b0814361 | 884 | goto skip; |
2ee867dc | 885 | |
903d23f0 JB |
886 | /* |
887 | * Hooray string manipulation, count is the size written NOT | |
888 | * INCLUDING THE \0, so size is now count+1 less than what we | |
889 | * had before, but we want to start writing the next bit from | |
890 | * the \0 so we only add count to buf. | |
891 | */ | |
892 | off += scnprintf(buf+off, size-off, "%s ", dname); | |
893 | ||
f7331648 TH |
894 | do { |
895 | seq = u64_stats_fetch_begin(&bis->sync); | |
2ee867dc | 896 | |
f7331648 TH |
897 | rbytes = bis->cur.bytes[BLKG_IOSTAT_READ]; |
898 | wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE]; | |
899 | dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD]; | |
900 | rios = bis->cur.ios[BLKG_IOSTAT_READ]; | |
901 | wios = bis->cur.ios[BLKG_IOSTAT_WRITE]; | |
902 | dios = bis->cur.ios[BLKG_IOSTAT_DISCARD]; | |
903 | } while (u64_stats_fetch_retry(&bis->sync, seq)); | |
2ee867dc | 904 | |
903d23f0 JB |
905 | if (rbytes || wbytes || rios || wios) { |
906 | has_stats = true; | |
907 | off += scnprintf(buf+off, size-off, | |
636620b6 TH |
908 | "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu", |
909 | rbytes, wbytes, rios, wios, | |
910 | dbytes, dios); | |
903d23f0 JB |
911 | } |
912 | ||
07b0fdec | 913 | if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) { |
d09d8df3 JB |
914 | has_stats = true; |
915 | off += scnprintf(buf+off, size-off, | |
916 | " use_delay=%d delay_nsec=%llu", | |
917 | atomic_read(&blkg->use_delay), | |
918 | (unsigned long long)atomic64_read(&blkg->delay_nsec)); | |
919 | } | |
920 | ||
903d23f0 JB |
921 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
922 | struct blkcg_policy *pol = blkcg_policy[i]; | |
923 | size_t written; | |
924 | ||
925 | if (!blkg->pd[i] || !pol->pd_stat_fn) | |
926 | continue; | |
927 | ||
928 | written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off); | |
929 | if (written) | |
930 | has_stats = true; | |
931 | off += written; | |
932 | } | |
07b0fdec | 933 | |
903d23f0 | 934 | if (has_stats) { |
f539da82 TH |
935 | if (off < size - 1) { |
936 | off += scnprintf(buf+off, size-off, "\n"); | |
937 | seq_commit(sf, off); | |
938 | } else { | |
939 | seq_commit(sf, -1); | |
940 | } | |
903d23f0 | 941 | } |
b0814361 TH |
942 | skip: |
943 | spin_unlock_irq(&blkg->q->queue_lock); | |
2ee867dc TH |
944 | } |
945 | ||
946 | rcu_read_unlock(); | |
947 | return 0; | |
948 | } | |
949 | ||
e1f3b941 | 950 | static struct cftype blkcg_files[] = { |
2ee867dc TH |
951 | { |
952 | .name = "stat", | |
953 | .seq_show = blkcg_print_stat, | |
954 | }, | |
955 | { } /* terminate */ | |
956 | }; | |
957 | ||
e1f3b941 | 958 | static struct cftype blkcg_legacy_files[] = { |
84c124da DS |
959 | { |
960 | .name = "reset_stats", | |
3c798398 | 961 | .write_u64 = blkcg_reset_stats, |
22084190 | 962 | }, |
4baf6e33 | 963 | { } /* terminate */ |
31e4c28d VG |
964 | }; |
965 | ||
59b57717 DZF |
966 | /* |
967 | * blkcg destruction is a three-stage process. | |
968 | * | |
969 | * 1. Destruction starts. The blkcg_css_offline() callback is invoked | |
970 | * which offlines writeback. Here we tie the next stage of blkg destruction | |
971 | * to the completion of writeback associated with the blkcg. This lets us | |
972 | * avoid punting potentially large amounts of outstanding writeback to root | |
973 | * while maintaining any ongoing policies. The next stage is triggered when | |
974 | * the nr_cgwbs count goes to zero. | |
975 | * | |
976 | * 2. When the nr_cgwbs count goes to zero, blkcg_destroy_blkgs() is called | |
977 | * and handles the destruction of blkgs. Here the css reference held by | |
978 | * the blkg is put back eventually allowing blkcg_css_free() to be called. | |
979 | * This work may occur in cgwb_release_workfn() on the cgwb_release | |
980 | * workqueue. Any submitted ios that fail to get the blkg ref will be | |
981 | * punted to the root_blkg. | |
982 | * | |
983 | * 3. Once the blkcg ref count goes to zero, blkcg_css_free() is called. | |
984 | * This finally frees the blkcg. | |
985 | */ | |
986 | ||
9f13ef67 | 987 | /** |
92fb9748 | 988 | * blkcg_css_offline - cgroup css_offline callback |
eb95419b | 989 | * @css: css of interest |
9f13ef67 | 990 | * |
59b57717 DZF |
991 | * This function is called when @css is about to go away. Here the cgwbs are |
992 | * offlined first and only once writeback associated with the blkcg has | |
993 | * finished do we start step 2 (see above). | |
9f13ef67 | 994 | */ |
eb95419b | 995 | static void blkcg_css_offline(struct cgroup_subsys_state *css) |
31e4c28d | 996 | { |
eb95419b | 997 | struct blkcg *blkcg = css_to_blkcg(css); |
b1c35769 | 998 | |
59b57717 DZF |
999 | /* this prevents anyone from attaching or migrating to this blkcg */ |
1000 | wb_blkcg_offline(blkcg); | |
1001 | ||
d866dbf6 TH |
1002 | /* put the base online pin allowing step 2 to be triggered */ |
1003 | blkcg_unpin_online(blkcg); | |
59b57717 DZF |
1004 | } |
1005 | ||
1006 | /** | |
1007 | * blkcg_destroy_blkgs - responsible for shooting down blkgs | |
1008 | * @blkcg: blkcg of interest | |
1009 | * | |
1010 | * blkgs should be removed while holding both q and blkcg locks. As blkcg lock | |
1011 | * is nested inside q lock, this function performs reverse double lock dancing. | |
1012 | * Destroying the blkgs releases the reference held on the blkcg's css allowing | |
1013 | * blkcg_css_free to eventually be called. | |
1014 | * | |
1015 | * This is the blkcg counterpart of ioc_release_fn(). | |
1016 | */ | |
1017 | void blkcg_destroy_blkgs(struct blkcg *blkcg) | |
1018 | { | |
9f13ef67 | 1019 | spin_lock_irq(&blkcg->lock); |
7ee9c562 | 1020 | |
4c699480 JQ |
1021 | while (!hlist_empty(&blkcg->blkg_list)) { |
1022 | struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first, | |
6b065462 | 1023 | struct blkcg_gq, blkcg_node); |
4c699480 JQ |
1024 | struct request_queue *q = blkg->q; |
1025 | ||
0d945c1f | 1026 | if (spin_trylock(&q->queue_lock)) { |
4c699480 | 1027 | blkg_destroy(blkg); |
0d945c1f | 1028 | spin_unlock(&q->queue_lock); |
4c699480 JQ |
1029 | } else { |
1030 | spin_unlock_irq(&blkcg->lock); | |
1031 | cpu_relax(); | |
1032 | spin_lock_irq(&blkcg->lock); | |
1033 | } | |
1034 | } | |
6b065462 | 1035 | |
4c699480 JQ |
1036 | spin_unlock_irq(&blkcg->lock); |
1037 | } | |
1038 | ||
eb95419b | 1039 | static void blkcg_css_free(struct cgroup_subsys_state *css) |
7ee9c562 | 1040 | { |
eb95419b | 1041 | struct blkcg *blkcg = css_to_blkcg(css); |
bc915e61 | 1042 | int i; |
7ee9c562 | 1043 | |
7876f930 | 1044 | mutex_lock(&blkcg_pol_mutex); |
e4a9bde9 | 1045 | |
7876f930 | 1046 | list_del(&blkcg->all_blkcgs_node); |
7876f930 | 1047 | |
bc915e61 | 1048 | for (i = 0; i < BLKCG_MAX_POLS; i++) |
e4a9bde9 TH |
1049 | if (blkcg->cpd[i]) |
1050 | blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); | |
1051 | ||
1052 | mutex_unlock(&blkcg_pol_mutex); | |
1053 | ||
bc915e61 | 1054 | kfree(blkcg); |
31e4c28d VG |
1055 | } |
1056 | ||
eb95419b TH |
1057 | static struct cgroup_subsys_state * |
1058 | blkcg_css_alloc(struct cgroup_subsys_state *parent_css) | |
31e4c28d | 1059 | { |
3c798398 | 1060 | struct blkcg *blkcg; |
e48453c3 AA |
1061 | struct cgroup_subsys_state *ret; |
1062 | int i; | |
31e4c28d | 1063 | |
7876f930 TH |
1064 | mutex_lock(&blkcg_pol_mutex); |
1065 | ||
eb95419b | 1066 | if (!parent_css) { |
3c798398 | 1067 | blkcg = &blkcg_root; |
bc915e61 TH |
1068 | } else { |
1069 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
1070 | if (!blkcg) { | |
1071 | ret = ERR_PTR(-ENOMEM); | |
4c18c9e9 | 1072 | goto unlock; |
bc915e61 | 1073 | } |
e48453c3 AA |
1074 | } |
1075 | ||
1076 | for (i = 0; i < BLKCG_MAX_POLS ; i++) { | |
1077 | struct blkcg_policy *pol = blkcg_policy[i]; | |
1078 | struct blkcg_policy_data *cpd; | |
1079 | ||
1080 | /* | |
1081 | * If the policy hasn't been attached yet, wait for it | |
1082 | * to be attached before doing anything else. Otherwise, | |
1083 | * check if the policy requires any specific per-cgroup | |
1084 | * data: if it does, allocate and initialize it. | |
1085 | */ | |
e4a9bde9 | 1086 | if (!pol || !pol->cpd_alloc_fn) |
e48453c3 AA |
1087 | continue; |
1088 | ||
e4a9bde9 | 1089 | cpd = pol->cpd_alloc_fn(GFP_KERNEL); |
e48453c3 AA |
1090 | if (!cpd) { |
1091 | ret = ERR_PTR(-ENOMEM); | |
1092 | goto free_pd_blkcg; | |
1093 | } | |
81437648 TH |
1094 | blkcg->cpd[i] = cpd; |
1095 | cpd->blkcg = blkcg; | |
e48453c3 | 1096 | cpd->plid = i; |
e4a9bde9 TH |
1097 | if (pol->cpd_init_fn) |
1098 | pol->cpd_init_fn(cpd); | |
e48453c3 | 1099 | } |
31e4c28d | 1100 | |
31e4c28d | 1101 | spin_lock_init(&blkcg->lock); |
d866dbf6 | 1102 | refcount_set(&blkcg->online_pin, 1); |
e00f4f4d | 1103 | INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN); |
31e4c28d | 1104 | INIT_HLIST_HEAD(&blkcg->blkg_list); |
52ebea74 TH |
1105 | #ifdef CONFIG_CGROUP_WRITEBACK |
1106 | INIT_LIST_HEAD(&blkcg->cgwb_list); | |
1107 | #endif | |
7876f930 TH |
1108 | list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs); |
1109 | ||
1110 | mutex_unlock(&blkcg_pol_mutex); | |
31e4c28d | 1111 | return &blkcg->css; |
e48453c3 AA |
1112 | |
1113 | free_pd_blkcg: | |
1114 | for (i--; i >= 0; i--) | |
e4a9bde9 TH |
1115 | if (blkcg->cpd[i]) |
1116 | blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); | |
4c18c9e9 | 1117 | |
1118 | if (blkcg != &blkcg_root) | |
1119 | kfree(blkcg); | |
1120 | unlock: | |
7876f930 | 1121 | mutex_unlock(&blkcg_pol_mutex); |
e48453c3 | 1122 | return ret; |
31e4c28d VG |
1123 | } |
1124 | ||
4308a434 TH |
1125 | static int blkcg_css_online(struct cgroup_subsys_state *css) |
1126 | { | |
1127 | struct blkcg *blkcg = css_to_blkcg(css); | |
1128 | struct blkcg *parent = blkcg_parent(blkcg); | |
1129 | ||
1130 | /* | |
1131 | * blkcg_pin_online() is used to delay blkcg offline so that blkgs | |
1132 | * don't go offline while cgwbs are still active on them. Pin the | |
1133 | * parent so that offline always happens towards the root. | |
1134 | */ | |
1135 | if (parent) | |
1136 | blkcg_pin_online(parent); | |
1137 | return 0; | |
1138 | } | |
1139 | ||
5efd6113 TH |
1140 | /** |
1141 | * blkcg_init_queue - initialize blkcg part of request queue | |
1142 | * @q: request_queue to initialize | |
1143 | * | |
c62b37d9 | 1144 | * Called from blk_alloc_queue(). Responsible for initializing blkcg |
5efd6113 TH |
1145 | * part of new request_queue @q. |
1146 | * | |
1147 | * RETURNS: | |
1148 | * 0 on success, -errno on failure. | |
1149 | */ | |
1150 | int blkcg_init_queue(struct request_queue *q) | |
1151 | { | |
d708f0d5 JA |
1152 | struct blkcg_gq *new_blkg, *blkg; |
1153 | bool preloaded; | |
ec13b1d6 TH |
1154 | int ret; |
1155 | ||
d708f0d5 JA |
1156 | new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL); |
1157 | if (!new_blkg) | |
1158 | return -ENOMEM; | |
1159 | ||
1160 | preloaded = !radix_tree_preload(GFP_KERNEL); | |
1161 | ||
bea54883 | 1162 | /* Make sure the root blkg exists. */ |
ec13b1d6 | 1163 | rcu_read_lock(); |
0d945c1f | 1164 | spin_lock_irq(&q->queue_lock); |
d708f0d5 | 1165 | blkg = blkg_create(&blkcg_root, q, new_blkg); |
901932a3 JB |
1166 | if (IS_ERR(blkg)) |
1167 | goto err_unlock; | |
1168 | q->root_blkg = blkg; | |
0d945c1f | 1169 | spin_unlock_irq(&q->queue_lock); |
ec13b1d6 TH |
1170 | rcu_read_unlock(); |
1171 | ||
d708f0d5 JA |
1172 | if (preloaded) |
1173 | radix_tree_preload_end(); | |
1174 | ||
27029b4b | 1175 | ret = blk_throtl_init(q); |
04be60b5 CH |
1176 | if (ret) |
1177 | goto err_destroy_all; | |
d7067512 | 1178 | |
27029b4b YY |
1179 | ret = blk_iolatency_init(q); |
1180 | if (ret) { | |
1181 | blk_throtl_exit(q); | |
04be60b5 | 1182 | goto err_destroy_all; |
27029b4b | 1183 | } |
04be60b5 | 1184 | return 0; |
901932a3 | 1185 | |
04be60b5 | 1186 | err_destroy_all: |
04be60b5 | 1187 | blkg_destroy_all(q); |
04be60b5 | 1188 | return ret; |
901932a3 | 1189 | err_unlock: |
0d945c1f | 1190 | spin_unlock_irq(&q->queue_lock); |
901932a3 JB |
1191 | rcu_read_unlock(); |
1192 | if (preloaded) | |
1193 | radix_tree_preload_end(); | |
1194 | return PTR_ERR(blkg); | |
5efd6113 TH |
1195 | } |
1196 | ||
5efd6113 TH |
1197 | /** |
1198 | * blkcg_exit_queue - exit and release blkcg part of request_queue | |
1199 | * @q: request_queue being released | |
1200 | * | |
7585d508 | 1201 | * Called from blk_exit_queue(). Responsible for exiting blkcg part. |
5efd6113 TH |
1202 | */ |
1203 | void blkcg_exit_queue(struct request_queue *q) | |
1204 | { | |
3c96cb32 | 1205 | blkg_destroy_all(q); |
5efd6113 TH |
1206 | blk_throtl_exit(q); |
1207 | } | |
1208 | ||
31e4c28d VG |
1209 | /* |
1210 | * We cannot support shared io contexts, as we have no mean to support | |
1211 | * two tasks with the same ioc in two different groups without major rework | |
1212 | * of the main cic data structures. For now we allow a task to change | |
1213 | * its cgroup only if it's the only owner of its ioc. | |
1214 | */ | |
1f7dd3e5 | 1215 | static int blkcg_can_attach(struct cgroup_taskset *tset) |
31e4c28d | 1216 | { |
bb9d97b6 | 1217 | struct task_struct *task; |
1f7dd3e5 | 1218 | struct cgroup_subsys_state *dst_css; |
31e4c28d VG |
1219 | struct io_context *ioc; |
1220 | int ret = 0; | |
1221 | ||
1222 | /* task_lock() is needed to avoid races with exit_io_context() */ | |
1f7dd3e5 | 1223 | cgroup_taskset_for_each(task, dst_css, tset) { |
bb9d97b6 TH |
1224 | task_lock(task); |
1225 | ioc = task->io_context; | |
1226 | if (ioc && atomic_read(&ioc->nr_tasks) > 1) | |
1227 | ret = -EINVAL; | |
1228 | task_unlock(task); | |
1229 | if (ret) | |
1230 | break; | |
1231 | } | |
31e4c28d VG |
1232 | return ret; |
1233 | } | |
1234 | ||
69d7fde5 TH |
1235 | static void blkcg_bind(struct cgroup_subsys_state *root_css) |
1236 | { | |
1237 | int i; | |
1238 | ||
1239 | mutex_lock(&blkcg_pol_mutex); | |
1240 | ||
1241 | for (i = 0; i < BLKCG_MAX_POLS; i++) { | |
1242 | struct blkcg_policy *pol = blkcg_policy[i]; | |
1243 | struct blkcg *blkcg; | |
1244 | ||
1245 | if (!pol || !pol->cpd_bind_fn) | |
1246 | continue; | |
1247 | ||
1248 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) | |
1249 | if (blkcg->cpd[pol->plid]) | |
1250 | pol->cpd_bind_fn(blkcg->cpd[pol->plid]); | |
1251 | } | |
1252 | mutex_unlock(&blkcg_pol_mutex); | |
1253 | } | |
1254 | ||
d09d8df3 JB |
1255 | static void blkcg_exit(struct task_struct *tsk) |
1256 | { | |
1257 | if (tsk->throttle_queue) | |
1258 | blk_put_queue(tsk->throttle_queue); | |
1259 | tsk->throttle_queue = NULL; | |
1260 | } | |
1261 | ||
c165b3e3 | 1262 | struct cgroup_subsys io_cgrp_subsys = { |
92fb9748 | 1263 | .css_alloc = blkcg_css_alloc, |
4308a434 | 1264 | .css_online = blkcg_css_online, |
92fb9748 TH |
1265 | .css_offline = blkcg_css_offline, |
1266 | .css_free = blkcg_css_free, | |
3c798398 | 1267 | .can_attach = blkcg_can_attach, |
f7331648 | 1268 | .css_rstat_flush = blkcg_rstat_flush, |
69d7fde5 | 1269 | .bind = blkcg_bind, |
2ee867dc | 1270 | .dfl_cftypes = blkcg_files, |
880f50e2 | 1271 | .legacy_cftypes = blkcg_legacy_files, |
c165b3e3 | 1272 | .legacy_name = "blkio", |
d09d8df3 | 1273 | .exit = blkcg_exit, |
1ced953b TH |
1274 | #ifdef CONFIG_MEMCG |
1275 | /* | |
1276 | * This ensures that, if available, memcg is automatically enabled | |
1277 | * together on the default hierarchy so that the owner cgroup can | |
1278 | * be retrieved from writeback pages. | |
1279 | */ | |
1280 | .depends_on = 1 << memory_cgrp_id, | |
1281 | #endif | |
676f7c8f | 1282 | }; |
c165b3e3 | 1283 | EXPORT_SYMBOL_GPL(io_cgrp_subsys); |
676f7c8f | 1284 | |
a2b1693b TH |
1285 | /** |
1286 | * blkcg_activate_policy - activate a blkcg policy on a request_queue | |
1287 | * @q: request_queue of interest | |
1288 | * @pol: blkcg policy to activate | |
1289 | * | |
1290 | * Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through | |
1291 | * bypass mode to populate its blkgs with policy_data for @pol. | |
1292 | * | |
1293 | * Activation happens with @q bypassed, so nobody would be accessing blkgs | |
1294 | * from IO path. Update of each blkg is protected by both queue and blkcg | |
1295 | * locks so that holding either lock and testing blkcg_policy_enabled() is | |
1296 | * always enough for dereferencing policy data. | |
1297 | * | |
1298 | * The caller is responsible for synchronizing [de]activations and policy | |
1299 | * [un]registerations. Returns 0 on success, -errno on failure. | |
1300 | */ | |
1301 | int blkcg_activate_policy(struct request_queue *q, | |
3c798398 | 1302 | const struct blkcg_policy *pol) |
a2b1693b | 1303 | { |
4c55f4f9 | 1304 | struct blkg_policy_data *pd_prealloc = NULL; |
9d179b86 | 1305 | struct blkcg_gq *blkg, *pinned_blkg = NULL; |
4c55f4f9 | 1306 | int ret; |
a2b1693b TH |
1307 | |
1308 | if (blkcg_policy_enabled(q, pol)) | |
1309 | return 0; | |
1310 | ||
344e9ffc | 1311 | if (queue_is_mq(q)) |
bd166ef1 | 1312 | blk_mq_freeze_queue(q); |
9d179b86 | 1313 | retry: |
0d945c1f | 1314 | spin_lock_irq(&q->queue_lock); |
a2b1693b | 1315 | |
9d179b86 | 1316 | /* blkg_list is pushed at the head, reverse walk to allocate parents first */ |
71c81407 | 1317 | list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) { |
4c55f4f9 TH |
1318 | struct blkg_policy_data *pd; |
1319 | ||
1320 | if (blkg->pd[pol->plid]) | |
1321 | continue; | |
a2b1693b | 1322 | |
9d179b86 TH |
1323 | /* If prealloc matches, use it; otherwise try GFP_NOWAIT */ |
1324 | if (blkg == pinned_blkg) { | |
1325 | pd = pd_prealloc; | |
1326 | pd_prealloc = NULL; | |
1327 | } else { | |
1328 | pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q, | |
1329 | blkg->blkcg); | |
1330 | } | |
1331 | ||
4c55f4f9 | 1332 | if (!pd) { |
9d179b86 TH |
1333 | /* |
1334 | * GFP_NOWAIT failed. Free the existing one and | |
1335 | * prealloc for @blkg w/ GFP_KERNEL. | |
1336 | */ | |
1337 | if (pinned_blkg) | |
1338 | blkg_put(pinned_blkg); | |
1339 | blkg_get(blkg); | |
1340 | pinned_blkg = blkg; | |
1341 | ||
0d945c1f | 1342 | spin_unlock_irq(&q->queue_lock); |
9d179b86 TH |
1343 | |
1344 | if (pd_prealloc) | |
1345 | pol->pd_free_fn(pd_prealloc); | |
1346 | pd_prealloc = pol->pd_alloc_fn(GFP_KERNEL, q, | |
1347 | blkg->blkcg); | |
1348 | if (pd_prealloc) | |
1349 | goto retry; | |
1350 | else | |
1351 | goto enomem; | |
4c55f4f9 | 1352 | } |
a2b1693b TH |
1353 | |
1354 | blkg->pd[pol->plid] = pd; | |
1355 | pd->blkg = blkg; | |
b276a876 | 1356 | pd->plid = pol->plid; |
a2b1693b TH |
1357 | } |
1358 | ||
9d179b86 TH |
1359 | /* all allocated, init in the same order */ |
1360 | if (pol->pd_init_fn) | |
1361 | list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) | |
1362 | pol->pd_init_fn(blkg->pd[pol->plid]); | |
1363 | ||
a2b1693b TH |
1364 | __set_bit(pol->plid, q->blkcg_pols); |
1365 | ret = 0; | |
4c55f4f9 | 1366 | |
0d945c1f | 1367 | spin_unlock_irq(&q->queue_lock); |
9d179b86 | 1368 | out: |
344e9ffc | 1369 | if (queue_is_mq(q)) |
bd166ef1 | 1370 | blk_mq_unfreeze_queue(q); |
9d179b86 TH |
1371 | if (pinned_blkg) |
1372 | blkg_put(pinned_blkg); | |
001bea73 TH |
1373 | if (pd_prealloc) |
1374 | pol->pd_free_fn(pd_prealloc); | |
a2b1693b | 1375 | return ret; |
9d179b86 TH |
1376 | |
1377 | enomem: | |
1378 | /* alloc failed, nothing's initialized yet, free everything */ | |
1379 | spin_lock_irq(&q->queue_lock); | |
1380 | list_for_each_entry(blkg, &q->blkg_list, q_node) { | |
1381 | if (blkg->pd[pol->plid]) { | |
1382 | pol->pd_free_fn(blkg->pd[pol->plid]); | |
1383 | blkg->pd[pol->plid] = NULL; | |
1384 | } | |
1385 | } | |
1386 | spin_unlock_irq(&q->queue_lock); | |
1387 | ret = -ENOMEM; | |
1388 | goto out; | |
a2b1693b TH |
1389 | } |
1390 | EXPORT_SYMBOL_GPL(blkcg_activate_policy); | |
1391 | ||
1392 | /** | |
1393 | * blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue | |
1394 | * @q: request_queue of interest | |
1395 | * @pol: blkcg policy to deactivate | |
1396 | * | |
1397 | * Deactivate @pol on @q. Follows the same synchronization rules as | |
1398 | * blkcg_activate_policy(). | |
1399 | */ | |
1400 | void blkcg_deactivate_policy(struct request_queue *q, | |
3c798398 | 1401 | const struct blkcg_policy *pol) |
a2b1693b | 1402 | { |
3c798398 | 1403 | struct blkcg_gq *blkg; |
a2b1693b TH |
1404 | |
1405 | if (!blkcg_policy_enabled(q, pol)) | |
1406 | return; | |
1407 | ||
344e9ffc | 1408 | if (queue_is_mq(q)) |
bd166ef1 | 1409 | blk_mq_freeze_queue(q); |
bd166ef1 | 1410 | |
0d945c1f | 1411 | spin_lock_irq(&q->queue_lock); |
a2b1693b TH |
1412 | |
1413 | __clear_bit(pol->plid, q->blkcg_pols); | |
1414 | ||
1415 | list_for_each_entry(blkg, &q->blkg_list, q_node) { | |
001bea73 | 1416 | if (blkg->pd[pol->plid]) { |
6b065462 | 1417 | if (pol->pd_offline_fn) |
a9520cd6 | 1418 | pol->pd_offline_fn(blkg->pd[pol->plid]); |
001bea73 TH |
1419 | pol->pd_free_fn(blkg->pd[pol->plid]); |
1420 | blkg->pd[pol->plid] = NULL; | |
1421 | } | |
a2b1693b TH |
1422 | } |
1423 | ||
0d945c1f | 1424 | spin_unlock_irq(&q->queue_lock); |
bd166ef1 | 1425 | |
344e9ffc | 1426 | if (queue_is_mq(q)) |
bd166ef1 | 1427 | blk_mq_unfreeze_queue(q); |
a2b1693b TH |
1428 | } |
1429 | EXPORT_SYMBOL_GPL(blkcg_deactivate_policy); | |
1430 | ||
8bd435b3 | 1431 | /** |
3c798398 TH |
1432 | * blkcg_policy_register - register a blkcg policy |
1433 | * @pol: blkcg policy to register | |
8bd435b3 | 1434 | * |
3c798398 TH |
1435 | * Register @pol with blkcg core. Might sleep and @pol may be modified on |
1436 | * successful registration. Returns 0 on success and -errno on failure. | |
8bd435b3 | 1437 | */ |
d5bf0291 | 1438 | int blkcg_policy_register(struct blkcg_policy *pol) |
3e252066 | 1439 | { |
06b285bd | 1440 | struct blkcg *blkcg; |
8bd435b3 | 1441 | int i, ret; |
e8989fae | 1442 | |
838f13bf | 1443 | mutex_lock(&blkcg_pol_register_mutex); |
bc0d6501 TH |
1444 | mutex_lock(&blkcg_pol_mutex); |
1445 | ||
8bd435b3 TH |
1446 | /* find an empty slot */ |
1447 | ret = -ENOSPC; | |
1448 | for (i = 0; i < BLKCG_MAX_POLS; i++) | |
3c798398 | 1449 | if (!blkcg_policy[i]) |
8bd435b3 | 1450 | break; |
01c5f85a JA |
1451 | if (i >= BLKCG_MAX_POLS) { |
1452 | pr_warn("blkcg_policy_register: BLKCG_MAX_POLS too small\n"); | |
838f13bf | 1453 | goto err_unlock; |
01c5f85a | 1454 | } |
035d10b2 | 1455 | |
e8401073 | 1456 | /* Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs */ |
1457 | if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) || | |
1458 | (!pol->pd_alloc_fn ^ !pol->pd_free_fn)) | |
1459 | goto err_unlock; | |
1460 | ||
06b285bd | 1461 | /* register @pol */ |
3c798398 | 1462 | pol->plid = i; |
06b285bd TH |
1463 | blkcg_policy[pol->plid] = pol; |
1464 | ||
1465 | /* allocate and install cpd's */ | |
e4a9bde9 | 1466 | if (pol->cpd_alloc_fn) { |
06b285bd TH |
1467 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { |
1468 | struct blkcg_policy_data *cpd; | |
1469 | ||
e4a9bde9 | 1470 | cpd = pol->cpd_alloc_fn(GFP_KERNEL); |
bbb427e3 | 1471 | if (!cpd) |
06b285bd | 1472 | goto err_free_cpds; |
06b285bd | 1473 | |
81437648 TH |
1474 | blkcg->cpd[pol->plid] = cpd; |
1475 | cpd->blkcg = blkcg; | |
06b285bd | 1476 | cpd->plid = pol->plid; |
86a5bba5 TH |
1477 | if (pol->cpd_init_fn) |
1478 | pol->cpd_init_fn(cpd); | |
06b285bd TH |
1479 | } |
1480 | } | |
1481 | ||
838f13bf | 1482 | mutex_unlock(&blkcg_pol_mutex); |
8bd435b3 | 1483 | |
8bd435b3 | 1484 | /* everything is in place, add intf files for the new policy */ |
2ee867dc TH |
1485 | if (pol->dfl_cftypes) |
1486 | WARN_ON(cgroup_add_dfl_cftypes(&io_cgrp_subsys, | |
1487 | pol->dfl_cftypes)); | |
880f50e2 | 1488 | if (pol->legacy_cftypes) |
c165b3e3 | 1489 | WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys, |
880f50e2 | 1490 | pol->legacy_cftypes)); |
838f13bf TH |
1491 | mutex_unlock(&blkcg_pol_register_mutex); |
1492 | return 0; | |
1493 | ||
06b285bd | 1494 | err_free_cpds: |
58a9edce | 1495 | if (pol->cpd_free_fn) { |
06b285bd | 1496 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { |
e4a9bde9 TH |
1497 | if (blkcg->cpd[pol->plid]) { |
1498 | pol->cpd_free_fn(blkcg->cpd[pol->plid]); | |
1499 | blkcg->cpd[pol->plid] = NULL; | |
1500 | } | |
06b285bd TH |
1501 | } |
1502 | } | |
1503 | blkcg_policy[pol->plid] = NULL; | |
838f13bf | 1504 | err_unlock: |
bc0d6501 | 1505 | mutex_unlock(&blkcg_pol_mutex); |
838f13bf | 1506 | mutex_unlock(&blkcg_pol_register_mutex); |
8bd435b3 | 1507 | return ret; |
3e252066 | 1508 | } |
3c798398 | 1509 | EXPORT_SYMBOL_GPL(blkcg_policy_register); |
3e252066 | 1510 | |
8bd435b3 | 1511 | /** |
3c798398 TH |
1512 | * blkcg_policy_unregister - unregister a blkcg policy |
1513 | * @pol: blkcg policy to unregister | |
8bd435b3 | 1514 | * |
3c798398 | 1515 | * Undo blkcg_policy_register(@pol). Might sleep. |
8bd435b3 | 1516 | */ |
3c798398 | 1517 | void blkcg_policy_unregister(struct blkcg_policy *pol) |
3e252066 | 1518 | { |
06b285bd TH |
1519 | struct blkcg *blkcg; |
1520 | ||
838f13bf | 1521 | mutex_lock(&blkcg_pol_register_mutex); |
bc0d6501 | 1522 | |
3c798398 | 1523 | if (WARN_ON(blkcg_policy[pol->plid] != pol)) |
8bd435b3 TH |
1524 | goto out_unlock; |
1525 | ||
1526 | /* kill the intf files first */ | |
2ee867dc TH |
1527 | if (pol->dfl_cftypes) |
1528 | cgroup_rm_cftypes(pol->dfl_cftypes); | |
880f50e2 TH |
1529 | if (pol->legacy_cftypes) |
1530 | cgroup_rm_cftypes(pol->legacy_cftypes); | |
44ea53de | 1531 | |
06b285bd | 1532 | /* remove cpds and unregister */ |
838f13bf | 1533 | mutex_lock(&blkcg_pol_mutex); |
06b285bd | 1534 | |
58a9edce | 1535 | if (pol->cpd_free_fn) { |
06b285bd | 1536 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { |
e4a9bde9 TH |
1537 | if (blkcg->cpd[pol->plid]) { |
1538 | pol->cpd_free_fn(blkcg->cpd[pol->plid]); | |
1539 | blkcg->cpd[pol->plid] = NULL; | |
1540 | } | |
06b285bd TH |
1541 | } |
1542 | } | |
3c798398 | 1543 | blkcg_policy[pol->plid] = NULL; |
06b285bd | 1544 | |
bc0d6501 | 1545 | mutex_unlock(&blkcg_pol_mutex); |
838f13bf TH |
1546 | out_unlock: |
1547 | mutex_unlock(&blkcg_pol_register_mutex); | |
3e252066 | 1548 | } |
3c798398 | 1549 | EXPORT_SYMBOL_GPL(blkcg_policy_unregister); |
903d23f0 | 1550 | |
d3f77dfd TH |
1551 | bool __blkcg_punt_bio_submit(struct bio *bio) |
1552 | { | |
1553 | struct blkcg_gq *blkg = bio->bi_blkg; | |
1554 | ||
1555 | /* consume the flag first */ | |
1556 | bio->bi_opf &= ~REQ_CGROUP_PUNT; | |
1557 | ||
1558 | /* never bounce for the root cgroup */ | |
1559 | if (!blkg->parent) | |
1560 | return false; | |
1561 | ||
1562 | spin_lock_bh(&blkg->async_bio_lock); | |
1563 | bio_list_add(&blkg->async_bios, bio); | |
1564 | spin_unlock_bh(&blkg->async_bio_lock); | |
1565 | ||
1566 | queue_work(blkcg_punt_bio_wq, &blkg->async_bio_work); | |
1567 | return true; | |
1568 | } | |
1569 | ||
d09d8df3 JB |
1570 | /* |
1571 | * Scale the accumulated delay based on how long it has been since we updated | |
1572 | * the delay. We only call this when we are adding delay, in case it's been a | |
1573 | * while since we added delay, and when we are checking to see if we need to | |
1574 | * delay a task, to account for any delays that may have occurred. | |
1575 | */ | |
1576 | static void blkcg_scale_delay(struct blkcg_gq *blkg, u64 now) | |
1577 | { | |
1578 | u64 old = atomic64_read(&blkg->delay_start); | |
1579 | ||
54c52e10 TH |
1580 | /* negative use_delay means no scaling, see blkcg_set_delay() */ |
1581 | if (atomic_read(&blkg->use_delay) < 0) | |
1582 | return; | |
1583 | ||
d09d8df3 JB |
1584 | /* |
1585 | * We only want to scale down every second. The idea here is that we | |
1586 | * want to delay people for min(delay_nsec, NSEC_PER_SEC) in a certain | |
1587 | * time window. We only want to throttle tasks for recent delay that | |
1588 | * has occurred, in 1 second time windows since that's the maximum | |
1589 | * things can be throttled. We save the current delay window in | |
1590 | * blkg->last_delay so we know what amount is still left to be charged | |
1591 | * to the blkg from this point onward. blkg->last_use keeps track of | |
1592 | * the use_delay counter. The idea is if we're unthrottling the blkg we | |
1593 | * are ok with whatever is happening now, and we can take away more of | |
1594 | * the accumulated delay as we've already throttled enough that | |
1595 | * everybody is happy with their IO latencies. | |
1596 | */ | |
1597 | if (time_before64(old + NSEC_PER_SEC, now) && | |
1598 | atomic64_cmpxchg(&blkg->delay_start, old, now) == old) { | |
1599 | u64 cur = atomic64_read(&blkg->delay_nsec); | |
1600 | u64 sub = min_t(u64, blkg->last_delay, now - old); | |
1601 | int cur_use = atomic_read(&blkg->use_delay); | |
1602 | ||
1603 | /* | |
1604 | * We've been unthrottled, subtract a larger chunk of our | |
1605 | * accumulated delay. | |
1606 | */ | |
1607 | if (cur_use < blkg->last_use) | |
1608 | sub = max_t(u64, sub, blkg->last_delay >> 1); | |
1609 | ||
1610 | /* | |
1611 | * This shouldn't happen, but handle it anyway. Our delay_nsec | |
1612 | * should only ever be growing except here where we subtract out | |
1613 | * min(last_delay, 1 second), but lord knows bugs happen and I'd | |
1614 | * rather not end up with negative numbers. | |
1615 | */ | |
1616 | if (unlikely(cur < sub)) { | |
1617 | atomic64_set(&blkg->delay_nsec, 0); | |
1618 | blkg->last_delay = 0; | |
1619 | } else { | |
1620 | atomic64_sub(sub, &blkg->delay_nsec); | |
1621 | blkg->last_delay = cur - sub; | |
1622 | } | |
1623 | blkg->last_use = cur_use; | |
1624 | } | |
1625 | } | |
1626 | ||
1627 | /* | |
1628 | * This is called when we want to actually walk up the hierarchy and check to | |
1629 | * see if we need to throttle, and then actually throttle if there is some | |
1630 | * accumulated delay. This should only be called upon return to user space so | |
1631 | * we're not holding some lock that would induce a priority inversion. | |
1632 | */ | |
1633 | static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay) | |
1634 | { | |
fd112c74 | 1635 | unsigned long pflags; |
5160a5a5 | 1636 | bool clamp; |
d09d8df3 JB |
1637 | u64 now = ktime_to_ns(ktime_get()); |
1638 | u64 exp; | |
1639 | u64 delay_nsec = 0; | |
1640 | int tok; | |
1641 | ||
1642 | while (blkg->parent) { | |
5160a5a5 TH |
1643 | int use_delay = atomic_read(&blkg->use_delay); |
1644 | ||
1645 | if (use_delay) { | |
1646 | u64 this_delay; | |
1647 | ||
d09d8df3 | 1648 | blkcg_scale_delay(blkg, now); |
5160a5a5 TH |
1649 | this_delay = atomic64_read(&blkg->delay_nsec); |
1650 | if (this_delay > delay_nsec) { | |
1651 | delay_nsec = this_delay; | |
1652 | clamp = use_delay > 0; | |
1653 | } | |
d09d8df3 JB |
1654 | } |
1655 | blkg = blkg->parent; | |
1656 | } | |
1657 | ||
1658 | if (!delay_nsec) | |
1659 | return; | |
1660 | ||
1661 | /* | |
1662 | * Let's not sleep for all eternity if we've amassed a huge delay. | |
1663 | * Swapping or metadata IO can accumulate 10's of seconds worth of | |
1664 | * delay, and we want userspace to be able to do _something_ so cap the | |
5160a5a5 TH |
1665 | * delays at 0.25s. If there's 10's of seconds worth of delay then the |
1666 | * tasks will be delayed for 0.25 second for every syscall. If | |
1667 | * blkcg_set_delay() was used as indicated by negative use_delay, the | |
1668 | * caller is responsible for regulating the range. | |
d09d8df3 | 1669 | */ |
5160a5a5 TH |
1670 | if (clamp) |
1671 | delay_nsec = min_t(u64, delay_nsec, 250 * NSEC_PER_MSEC); | |
d09d8df3 | 1672 | |
fd112c74 JB |
1673 | if (use_memdelay) |
1674 | psi_memstall_enter(&pflags); | |
d09d8df3 JB |
1675 | |
1676 | exp = ktime_add_ns(now, delay_nsec); | |
1677 | tok = io_schedule_prepare(); | |
1678 | do { | |
1679 | __set_current_state(TASK_KILLABLE); | |
1680 | if (!schedule_hrtimeout(&exp, HRTIMER_MODE_ABS)) | |
1681 | break; | |
1682 | } while (!fatal_signal_pending(current)); | |
1683 | io_schedule_finish(tok); | |
fd112c74 JB |
1684 | |
1685 | if (use_memdelay) | |
1686 | psi_memstall_leave(&pflags); | |
d09d8df3 JB |
1687 | } |
1688 | ||
1689 | /** | |
1690 | * blkcg_maybe_throttle_current - throttle the current task if it has been marked | |
1691 | * | |
1692 | * This is only called if we've been marked with set_notify_resume(). Obviously | |
1693 | * we can be set_notify_resume() for reasons other than blkcg throttling, so we | |
1694 | * check to see if current->throttle_queue is set and if not this doesn't do | |
1695 | * anything. This should only ever be called by the resume code, it's not meant | |
1696 | * to be called by people willy-nilly as it will actually do the work to | |
1697 | * throttle the task if it is setup for throttling. | |
1698 | */ | |
1699 | void blkcg_maybe_throttle_current(void) | |
1700 | { | |
1701 | struct request_queue *q = current->throttle_queue; | |
1702 | struct cgroup_subsys_state *css; | |
1703 | struct blkcg *blkcg; | |
1704 | struct blkcg_gq *blkg; | |
1705 | bool use_memdelay = current->use_memdelay; | |
1706 | ||
1707 | if (!q) | |
1708 | return; | |
1709 | ||
1710 | current->throttle_queue = NULL; | |
1711 | current->use_memdelay = false; | |
1712 | ||
1713 | rcu_read_lock(); | |
1714 | css = kthread_blkcg(); | |
1715 | if (css) | |
1716 | blkcg = css_to_blkcg(css); | |
1717 | else | |
1718 | blkcg = css_to_blkcg(task_css(current, io_cgrp_id)); | |
1719 | ||
1720 | if (!blkcg) | |
1721 | goto out; | |
1722 | blkg = blkg_lookup(blkcg, q); | |
1723 | if (!blkg) | |
1724 | goto out; | |
7754f669 | 1725 | if (!blkg_tryget(blkg)) |
d09d8df3 JB |
1726 | goto out; |
1727 | rcu_read_unlock(); | |
d09d8df3 JB |
1728 | |
1729 | blkcg_maybe_throttle_blkg(blkg, use_memdelay); | |
1730 | blkg_put(blkg); | |
cc7ecc25 | 1731 | blk_put_queue(q); |
d09d8df3 JB |
1732 | return; |
1733 | out: | |
1734 | rcu_read_unlock(); | |
1735 | blk_put_queue(q); | |
1736 | } | |
d09d8df3 JB |
1737 | |
1738 | /** | |
1739 | * blkcg_schedule_throttle - this task needs to check for throttling | |
537d71b3 BVA |
1740 | * @q: the request queue IO was submitted on |
1741 | * @use_memdelay: do we charge this to memory delay for PSI | |
d09d8df3 JB |
1742 | * |
1743 | * This is called by the IO controller when we know there's delay accumulated | |
1744 | * for the blkg for this task. We do not pass the blkg because there are places | |
1745 | * we call this that may not have that information, the swapping code for | |
1746 | * instance will only have a request_queue at that point. This set's the | |
1747 | * notify_resume for the task to check and see if it requires throttling before | |
1748 | * returning to user space. | |
1749 | * | |
1750 | * We will only schedule once per syscall. You can call this over and over | |
1751 | * again and it will only do the check once upon return to user space, and only | |
1752 | * throttle once. If the task needs to be throttled again it'll need to be | |
1753 | * re-set at the next time we see the task. | |
1754 | */ | |
1755 | void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) | |
1756 | { | |
1757 | if (unlikely(current->flags & PF_KTHREAD)) | |
1758 | return; | |
1759 | ||
1760 | if (!blk_get_queue(q)) | |
1761 | return; | |
1762 | ||
1763 | if (current->throttle_queue) | |
1764 | blk_put_queue(current->throttle_queue); | |
1765 | current->throttle_queue = q; | |
1766 | if (use_memdelay) | |
1767 | current->use_memdelay = use_memdelay; | |
1768 | set_notify_resume(current); | |
1769 | } | |
d09d8df3 JB |
1770 | |
1771 | /** | |
1772 | * blkcg_add_delay - add delay to this blkg | |
537d71b3 BVA |
1773 | * @blkg: blkg of interest |
1774 | * @now: the current time in nanoseconds | |
1775 | * @delta: how many nanoseconds of delay to add | |
d09d8df3 JB |
1776 | * |
1777 | * Charge @delta to the blkg's current delay accumulation. This is used to | |
1778 | * throttle tasks if an IO controller thinks we need more throttling. | |
1779 | */ | |
1780 | void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta) | |
1781 | { | |
54c52e10 TH |
1782 | if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0)) |
1783 | return; | |
d09d8df3 JB |
1784 | blkcg_scale_delay(blkg, now); |
1785 | atomic64_add(delta, &blkg->delay_nsec); | |
1786 | } | |
d09d8df3 | 1787 | |
28fc591f CH |
1788 | /** |
1789 | * blkg_tryget_closest - try and get a blkg ref on the closet blkg | |
13c7863d CH |
1790 | * @bio: target bio |
1791 | * @css: target css | |
28fc591f | 1792 | * |
13c7863d CH |
1793 | * As the failure mode here is to walk up the blkg tree, this ensure that the |
1794 | * blkg->parent pointers are always valid. This returns the blkg that it ended | |
1795 | * up taking a reference on or %NULL if no reference was taken. | |
28fc591f | 1796 | */ |
13c7863d CH |
1797 | static inline struct blkcg_gq *blkg_tryget_closest(struct bio *bio, |
1798 | struct cgroup_subsys_state *css) | |
28fc591f | 1799 | { |
13c7863d | 1800 | struct blkcg_gq *blkg, *ret_blkg = NULL; |
28fc591f | 1801 | |
13c7863d CH |
1802 | rcu_read_lock(); |
1803 | blkg = blkg_lookup_create(css_to_blkcg(css), bio->bi_disk->queue); | |
28fc591f CH |
1804 | while (blkg) { |
1805 | if (blkg_tryget(blkg)) { | |
1806 | ret_blkg = blkg; | |
1807 | break; | |
1808 | } | |
1809 | blkg = blkg->parent; | |
1810 | } | |
13c7863d | 1811 | rcu_read_unlock(); |
28fc591f CH |
1812 | |
1813 | return ret_blkg; | |
1814 | } | |
1815 | ||
1816 | /** | |
1817 | * bio_associate_blkg_from_css - associate a bio with a specified css | |
1818 | * @bio: target bio | |
1819 | * @css: target css | |
1820 | * | |
1821 | * Associate @bio with the blkg found by combining the css's blkg and the | |
1822 | * request_queue of the @bio. An association failure is handled by walking up | |
1823 | * the blkg tree. Therefore, the blkg associated can be anything between @blkg | |
1824 | * and q->root_blkg. This situation only happens when a cgroup is dying and | |
1825 | * then the remaining bios will spill to the closest alive blkg. | |
1826 | * | |
1827 | * A reference will be taken on the blkg and will be released when @bio is | |
1828 | * freed. | |
1829 | */ | |
1830 | void bio_associate_blkg_from_css(struct bio *bio, | |
1831 | struct cgroup_subsys_state *css) | |
1832 | { | |
28fc591f CH |
1833 | if (bio->bi_blkg) |
1834 | blkg_put(bio->bi_blkg); | |
1835 | ||
a5b97526 | 1836 | if (css && css->parent) { |
13c7863d | 1837 | bio->bi_blkg = blkg_tryget_closest(bio, css); |
a5b97526 | 1838 | } else { |
13c7863d CH |
1839 | blkg_get(bio->bi_disk->queue->root_blkg); |
1840 | bio->bi_blkg = bio->bi_disk->queue->root_blkg; | |
a5b97526 | 1841 | } |
28fc591f CH |
1842 | } |
1843 | EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); | |
1844 | ||
1845 | /** | |
1846 | * bio_associate_blkg - associate a bio with a blkg | |
1847 | * @bio: target bio | |
1848 | * | |
1849 | * Associate @bio with the blkg found from the bio's css and request_queue. | |
1850 | * If one is not found, bio_lookup_blkg() creates the blkg. If a blkg is | |
1851 | * already associated, the css is reused and association redone as the | |
1852 | * request_queue may have changed. | |
1853 | */ | |
1854 | void bio_associate_blkg(struct bio *bio) | |
1855 | { | |
1856 | struct cgroup_subsys_state *css; | |
1857 | ||
1858 | rcu_read_lock(); | |
1859 | ||
1860 | if (bio->bi_blkg) | |
1861 | css = &bio_blkcg(bio)->css; | |
1862 | else | |
1863 | css = blkcg_css(); | |
1864 | ||
1865 | bio_associate_blkg_from_css(bio, css); | |
1866 | ||
1867 | rcu_read_unlock(); | |
1868 | } | |
1869 | EXPORT_SYMBOL_GPL(bio_associate_blkg); | |
1870 | ||
1871 | /** | |
1872 | * bio_clone_blkg_association - clone blkg association from src to dst bio | |
1873 | * @dst: destination bio | |
1874 | * @src: source bio | |
1875 | */ | |
1876 | void bio_clone_blkg_association(struct bio *dst, struct bio *src) | |
1877 | { | |
1878 | if (src->bi_blkg) { | |
1879 | if (dst->bi_blkg) | |
1880 | blkg_put(dst->bi_blkg); | |
1881 | blkg_get(src->bi_blkg); | |
1882 | dst->bi_blkg = src->bi_blkg; | |
1883 | } | |
1884 | } | |
1885 | EXPORT_SYMBOL_GPL(bio_clone_blkg_association); | |
1886 | ||
db18a53e CH |
1887 | static int blk_cgroup_io_type(struct bio *bio) |
1888 | { | |
1889 | if (op_is_discard(bio->bi_opf)) | |
1890 | return BLKG_IOSTAT_DISCARD; | |
1891 | if (op_is_write(bio->bi_opf)) | |
1892 | return BLKG_IOSTAT_WRITE; | |
1893 | return BLKG_IOSTAT_READ; | |
1894 | } | |
1895 | ||
1896 | void blk_cgroup_bio_start(struct bio *bio) | |
1897 | { | |
1898 | int rwd = blk_cgroup_io_type(bio), cpu; | |
1899 | struct blkg_iostat_set *bis; | |
1900 | ||
1901 | cpu = get_cpu(); | |
1902 | bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); | |
1903 | u64_stats_update_begin(&bis->sync); | |
1904 | ||
1905 | /* | |
1906 | * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split | |
1907 | * bio and we would have already accounted for the size of the bio. | |
1908 | */ | |
1909 | if (!bio_flagged(bio, BIO_CGROUP_ACCT)) { | |
1910 | bio_set_flag(bio, BIO_CGROUP_ACCT); | |
0b8cc25d | 1911 | bis->cur.bytes[rwd] += bio->bi_iter.bi_size; |
db18a53e CH |
1912 | } |
1913 | bis->cur.ios[rwd]++; | |
1914 | ||
1915 | u64_stats_update_end(&bis->sync); | |
1916 | if (cgroup_subsys_on_dfl(io_cgrp_subsys)) | |
1917 | cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); | |
1918 | put_cpu(); | |
1919 | } | |
1920 | ||
d3f77dfd TH |
1921 | static int __init blkcg_init(void) |
1922 | { | |
1923 | blkcg_punt_bio_wq = alloc_workqueue("blkcg_punt_bio", | |
1924 | WQ_MEM_RECLAIM | WQ_FREEZABLE | | |
1925 | WQ_UNBOUND | WQ_SYSFS, 0); | |
1926 | if (!blkcg_punt_bio_wq) | |
1927 | return -ENOMEM; | |
1928 | return 0; | |
1929 | } | |
1930 | subsys_initcall(blkcg_init); | |
1931 | ||
903d23f0 JB |
1932 | module_param(blkcg_debug_stats, bool, 0644); |
1933 | MODULE_PARM_DESC(blkcg_debug_stats, "True if you want debug stats, false if not"); |