Commit | Line | Data |
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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> |
72e06c25 | 26 | #include <linux/delay.h> |
9a9e8a26 | 27 | #include <linux/atomic.h> |
36aa9e5f | 28 | #include <linux/ctype.h> |
03248add | 29 | #include <linux/resume_user_mode.h> |
fd112c74 | 30 | #include <linux/psi.h> |
82d981d4 | 31 | #include <linux/part_stat.h> |
5efd6113 | 32 | #include "blk.h" |
672fdcf0 | 33 | #include "blk-cgroup.h" |
556910e3 | 34 | #include "blk-ioprio.h" |
a7b36ee6 | 35 | #include "blk-throttle.h" |
3e252066 | 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 | |
a731763f YK |
60 | #define BLKG_DESTROY_BATCH_SIZE 64 |
61 | ||
bc5fee91 CH |
62 | /** |
63 | * blkcg_css - find the current css | |
64 | * | |
65 | * Find the css associated with either the kthread or the current task. | |
66 | * This may return a dying css, so it is up to the caller to use tryget logic | |
67 | * to confirm it is alive and well. | |
68 | */ | |
69 | static struct cgroup_subsys_state *blkcg_css(void) | |
70 | { | |
71 | struct cgroup_subsys_state *css; | |
72 | ||
73 | css = kthread_blkcg(); | |
74 | if (css) | |
75 | return css; | |
76 | return task_css(current, io_cgrp_id); | |
77 | } | |
78 | ||
a2b1693b | 79 | static bool blkcg_policy_enabled(struct request_queue *q, |
3c798398 | 80 | const struct blkcg_policy *pol) |
a2b1693b TH |
81 | { |
82 | return pol && test_bit(pol->plid, q->blkcg_pols); | |
83 | } | |
84 | ||
d578c770 | 85 | static void blkg_free_workfn(struct work_struct *work) |
0381411e | 86 | { |
d578c770 ML |
87 | struct blkcg_gq *blkg = container_of(work, struct blkcg_gq, |
88 | free_work); | |
e8989fae | 89 | int i; |
549d3aa8 | 90 | |
db613670 | 91 | for (i = 0; i < BLKCG_MAX_POLS; i++) |
001bea73 TH |
92 | if (blkg->pd[i]) |
93 | blkcg_policy[i]->pd_free_fn(blkg->pd[i]); | |
e8989fae | 94 | |
0a9a25ca ML |
95 | if (blkg->q) |
96 | blk_put_queue(blkg->q); | |
f7331648 | 97 | free_percpu(blkg->iostat_cpu); |
ef069b97 | 98 | percpu_ref_exit(&blkg->refcnt); |
549d3aa8 | 99 | kfree(blkg); |
0381411e TH |
100 | } |
101 | ||
d578c770 ML |
102 | /** |
103 | * blkg_free - free a blkg | |
104 | * @blkg: blkg to free | |
105 | * | |
106 | * Free @blkg which may be partially allocated. | |
107 | */ | |
108 | static void blkg_free(struct blkcg_gq *blkg) | |
109 | { | |
110 | if (!blkg) | |
111 | return; | |
112 | ||
113 | /* | |
114 | * Both ->pd_free_fn() and request queue's release handler may | |
115 | * sleep, so free us by scheduling one work func | |
116 | */ | |
117 | INIT_WORK(&blkg->free_work, blkg_free_workfn); | |
118 | schedule_work(&blkg->free_work); | |
119 | } | |
120 | ||
7fcf2b03 DZ |
121 | static void __blkg_release(struct rcu_head *rcu) |
122 | { | |
123 | struct blkcg_gq *blkg = container_of(rcu, struct blkcg_gq, rcu_head); | |
124 | ||
d3f77dfd TH |
125 | WARN_ON(!bio_list_empty(&blkg->async_bios)); |
126 | ||
7fcf2b03 DZ |
127 | /* release the blkcg and parent blkg refs this blkg has been holding */ |
128 | css_put(&blkg->blkcg->css); | |
129 | if (blkg->parent) | |
130 | blkg_put(blkg->parent); | |
7fcf2b03 DZ |
131 | blkg_free(blkg); |
132 | } | |
133 | ||
134 | /* | |
135 | * A group is RCU protected, but having an rcu lock does not mean that one | |
136 | * can access all the fields of blkg and assume these are valid. For | |
137 | * example, don't try to follow throtl_data and request queue links. | |
138 | * | |
139 | * Having a reference to blkg under an rcu allows accesses to only values | |
140 | * local to groups like group stats and group rate limits. | |
141 | */ | |
142 | static void blkg_release(struct percpu_ref *ref) | |
143 | { | |
144 | struct blkcg_gq *blkg = container_of(ref, struct blkcg_gq, refcnt); | |
145 | ||
146 | call_rcu(&blkg->rcu_head, __blkg_release); | |
147 | } | |
148 | ||
d3f77dfd TH |
149 | static void blkg_async_bio_workfn(struct work_struct *work) |
150 | { | |
151 | struct blkcg_gq *blkg = container_of(work, struct blkcg_gq, | |
152 | async_bio_work); | |
153 | struct bio_list bios = BIO_EMPTY_LIST; | |
154 | struct bio *bio; | |
192f1c6b XT |
155 | struct blk_plug plug; |
156 | bool need_plug = false; | |
d3f77dfd TH |
157 | |
158 | /* as long as there are pending bios, @blkg can't go away */ | |
159 | spin_lock_bh(&blkg->async_bio_lock); | |
160 | bio_list_merge(&bios, &blkg->async_bios); | |
161 | bio_list_init(&blkg->async_bios); | |
162 | spin_unlock_bh(&blkg->async_bio_lock); | |
163 | ||
192f1c6b XT |
164 | /* start plug only when bio_list contains at least 2 bios */ |
165 | if (bios.head && bios.head->bi_next) { | |
166 | need_plug = true; | |
167 | blk_start_plug(&plug); | |
168 | } | |
d3f77dfd TH |
169 | while ((bio = bio_list_pop(&bios))) |
170 | submit_bio(bio); | |
192f1c6b XT |
171 | if (need_plug) |
172 | blk_finish_plug(&plug); | |
d3f77dfd TH |
173 | } |
174 | ||
bbb1ebe7 CH |
175 | /** |
176 | * bio_blkcg_css - return the blkcg CSS associated with a bio | |
177 | * @bio: target bio | |
178 | * | |
179 | * This returns the CSS for the blkcg associated with a bio, or %NULL if not | |
180 | * associated. Callers are expected to either handle %NULL or know association | |
181 | * has been done prior to calling this. | |
182 | */ | |
183 | struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio) | |
184 | { | |
185 | if (!bio || !bio->bi_blkg) | |
186 | return NULL; | |
187 | return &bio->bi_blkg->blkcg->css; | |
188 | } | |
189 | EXPORT_SYMBOL_GPL(bio_blkcg_css); | |
190 | ||
397c9f46 CH |
191 | /** |
192 | * blkcg_parent - get the parent of a blkcg | |
193 | * @blkcg: blkcg of interest | |
194 | * | |
195 | * Return the parent blkcg of @blkcg. Can be called anytime. | |
196 | */ | |
197 | static inline struct blkcg *blkcg_parent(struct blkcg *blkcg) | |
198 | { | |
199 | return css_to_blkcg(blkcg->css.parent); | |
200 | } | |
201 | ||
0381411e TH |
202 | /** |
203 | * blkg_alloc - allocate a blkg | |
204 | * @blkcg: block cgroup the new blkg is associated with | |
99e60387 | 205 | * @disk: gendisk the new blkg is associated with |
15974993 | 206 | * @gfp_mask: allocation mask to use |
0381411e | 207 | * |
e8989fae | 208 | * Allocate a new blkg assocating @blkcg and @q. |
0381411e | 209 | */ |
99e60387 | 210 | static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk, |
15974993 | 211 | gfp_t gfp_mask) |
0381411e | 212 | { |
3c798398 | 213 | struct blkcg_gq *blkg; |
f7331648 | 214 | int i, cpu; |
0381411e TH |
215 | |
216 | /* alloc and init base part */ | |
99e60387 | 217 | blkg = kzalloc_node(sizeof(*blkg), gfp_mask, disk->queue->node); |
0381411e TH |
218 | if (!blkg) |
219 | return NULL; | |
220 | ||
ef069b97 TH |
221 | if (percpu_ref_init(&blkg->refcnt, blkg_release, 0, gfp_mask)) |
222 | goto err_free; | |
223 | ||
f7331648 TH |
224 | blkg->iostat_cpu = alloc_percpu_gfp(struct blkg_iostat_set, gfp_mask); |
225 | if (!blkg->iostat_cpu) | |
77ea7338 TH |
226 | goto err_free; |
227 | ||
99e60387 | 228 | if (!blk_get_queue(disk->queue)) |
0a9a25ca ML |
229 | goto err_free; |
230 | ||
99e60387 | 231 | blkg->q = disk->queue; |
e8989fae | 232 | INIT_LIST_HEAD(&blkg->q_node); |
d3f77dfd TH |
233 | spin_lock_init(&blkg->async_bio_lock); |
234 | bio_list_init(&blkg->async_bios); | |
235 | INIT_WORK(&blkg->async_bio_work, blkg_async_bio_workfn); | |
0381411e | 236 | blkg->blkcg = blkcg; |
0381411e | 237 | |
f7331648 TH |
238 | u64_stats_init(&blkg->iostat.sync); |
239 | for_each_possible_cpu(cpu) | |
240 | u64_stats_init(&per_cpu_ptr(blkg->iostat_cpu, cpu)->sync); | |
241 | ||
8bd435b3 | 242 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
3c798398 | 243 | struct blkcg_policy *pol = blkcg_policy[i]; |
e8989fae | 244 | struct blkg_policy_data *pd; |
0381411e | 245 | |
99e60387 | 246 | if (!blkcg_policy_enabled(disk->queue, pol)) |
e8989fae TH |
247 | continue; |
248 | ||
249 | /* alloc per-policy data and attach it to blkg */ | |
99e60387 | 250 | pd = pol->pd_alloc_fn(gfp_mask, disk->queue, blkcg); |
a051661c TH |
251 | if (!pd) |
252 | goto err_free; | |
549d3aa8 | 253 | |
e8989fae TH |
254 | blkg->pd[i] = pd; |
255 | pd->blkg = blkg; | |
b276a876 | 256 | pd->plid = i; |
e8989fae TH |
257 | } |
258 | ||
0381411e | 259 | return blkg; |
a051661c TH |
260 | |
261 | err_free: | |
262 | blkg_free(blkg); | |
263 | return NULL; | |
0381411e TH |
264 | } |
265 | ||
15974993 | 266 | /* |
d708f0d5 JA |
267 | * If @new_blkg is %NULL, this function tries to allocate a new one as |
268 | * necessary using %GFP_NOWAIT. @new_blkg is always consumed on return. | |
15974993 | 269 | */ |
99e60387 | 270 | static struct blkcg_gq *blkg_create(struct blkcg *blkcg, struct gendisk *disk, |
d708f0d5 | 271 | struct blkcg_gq *new_blkg) |
5624a4e4 | 272 | { |
d708f0d5 | 273 | struct blkcg_gq *blkg; |
f427d909 | 274 | int i, ret; |
5624a4e4 | 275 | |
99e60387 | 276 | lockdep_assert_held(&disk->queue->queue_lock); |
cd1604fa | 277 | |
0273ac34 | 278 | /* request_queue is dying, do not create/recreate a blkg */ |
99e60387 | 279 | if (blk_queue_dying(disk->queue)) { |
0273ac34 DZ |
280 | ret = -ENODEV; |
281 | goto err_free_blkg; | |
282 | } | |
283 | ||
7ee9c562 | 284 | /* blkg holds a reference to blkcg */ |
ec903c0c | 285 | if (!css_tryget_online(&blkcg->css)) { |
20386ce0 | 286 | ret = -ENODEV; |
93e6d5d8 | 287 | goto err_free_blkg; |
15974993 | 288 | } |
cd1604fa | 289 | |
d708f0d5 JA |
290 | /* allocate */ |
291 | if (!new_blkg) { | |
99e60387 | 292 | new_blkg = blkg_alloc(blkcg, disk, GFP_NOWAIT | __GFP_NOWARN); |
d708f0d5 JA |
293 | if (unlikely(!new_blkg)) { |
294 | ret = -ENOMEM; | |
8c911f3d | 295 | goto err_put_css; |
15974993 TH |
296 | } |
297 | } | |
d708f0d5 | 298 | blkg = new_blkg; |
cd1604fa | 299 | |
db613670 | 300 | /* link parent */ |
3c547865 | 301 | if (blkcg_parent(blkcg)) { |
99e60387 | 302 | blkg->parent = blkg_lookup(blkcg_parent(blkcg), disk->queue); |
3c547865 | 303 | if (WARN_ON_ONCE(!blkg->parent)) { |
20386ce0 | 304 | ret = -ENODEV; |
8c911f3d | 305 | goto err_put_css; |
3c547865 TH |
306 | } |
307 | blkg_get(blkg->parent); | |
308 | } | |
309 | ||
db613670 TH |
310 | /* invoke per-policy init */ |
311 | for (i = 0; i < BLKCG_MAX_POLS; i++) { | |
312 | struct blkcg_policy *pol = blkcg_policy[i]; | |
313 | ||
314 | if (blkg->pd[i] && pol->pd_init_fn) | |
a9520cd6 | 315 | pol->pd_init_fn(blkg->pd[i]); |
db613670 TH |
316 | } |
317 | ||
318 | /* insert */ | |
cd1604fa | 319 | spin_lock(&blkcg->lock); |
99e60387 | 320 | ret = radix_tree_insert(&blkcg->blkg_tree, disk->queue->id, blkg); |
a637120e TH |
321 | if (likely(!ret)) { |
322 | hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list); | |
99e60387 | 323 | list_add(&blkg->q_node, &disk->queue->blkg_list); |
f427d909 TH |
324 | |
325 | for (i = 0; i < BLKCG_MAX_POLS; i++) { | |
326 | struct blkcg_policy *pol = blkcg_policy[i]; | |
327 | ||
328 | if (blkg->pd[i] && pol->pd_online_fn) | |
a9520cd6 | 329 | pol->pd_online_fn(blkg->pd[i]); |
f427d909 | 330 | } |
a637120e | 331 | } |
f427d909 | 332 | blkg->online = true; |
cd1604fa | 333 | spin_unlock(&blkcg->lock); |
496fb780 | 334 | |
ec13b1d6 | 335 | if (!ret) |
a637120e | 336 | return blkg; |
15974993 | 337 | |
3c547865 TH |
338 | /* @blkg failed fully initialized, use the usual release path */ |
339 | blkg_put(blkg); | |
340 | return ERR_PTR(ret); | |
341 | ||
d708f0d5 | 342 | err_put_css: |
496fb780 | 343 | css_put(&blkcg->css); |
93e6d5d8 | 344 | err_free_blkg: |
d708f0d5 | 345 | blkg_free(new_blkg); |
93e6d5d8 | 346 | return ERR_PTR(ret); |
31e4c28d | 347 | } |
3c96cb32 | 348 | |
86cde6b6 | 349 | /** |
8c546287 | 350 | * blkg_lookup_create - lookup blkg, try to create one if not there |
86cde6b6 | 351 | * @blkcg: blkcg of interest |
99e60387 | 352 | * @disk: gendisk of interest |
86cde6b6 | 353 | * |
99e60387 | 354 | * Lookup blkg for the @blkcg - @disk pair. If it doesn't exist, try to |
3c547865 TH |
355 | * create one. blkg creation is performed recursively from blkcg_root such |
356 | * that all non-root blkg's have access to the parent blkg. This function | |
99e60387 | 357 | * should be called under RCU read lock and takes @disk->queue->queue_lock. |
86cde6b6 | 358 | * |
beea9da0 DZ |
359 | * Returns the blkg or the closest blkg if blkg_create() fails as it walks |
360 | * down from root. | |
86cde6b6 | 361 | */ |
8c546287 | 362 | static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, |
99e60387 | 363 | struct gendisk *disk) |
3c96cb32 | 364 | { |
99e60387 | 365 | struct request_queue *q = disk->queue; |
86cde6b6 | 366 | struct blkcg_gq *blkg; |
8c546287 | 367 | unsigned long flags; |
86cde6b6 TH |
368 | |
369 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
86cde6b6 | 370 | |
8c546287 | 371 | blkg = blkg_lookup(blkcg, q); |
86cde6b6 TH |
372 | if (blkg) |
373 | return blkg; | |
374 | ||
8c546287 | 375 | spin_lock_irqsave(&q->queue_lock, flags); |
4a69f325 CH |
376 | blkg = blkg_lookup(blkcg, q); |
377 | if (blkg) { | |
5765033c CH |
378 | if (blkcg != &blkcg_root && |
379 | blkg != rcu_dereference(blkcg->blkg_hint)) | |
380 | rcu_assign_pointer(blkcg->blkg_hint, blkg); | |
8c546287 | 381 | goto found; |
4a69f325 | 382 | } |
8c546287 | 383 | |
3c547865 TH |
384 | /* |
385 | * Create blkgs walking down from blkcg_root to @blkcg, so that all | |
beea9da0 DZ |
386 | * non-root blkgs have access to their parents. Returns the closest |
387 | * blkg to the intended blkg should blkg_create() fail. | |
3c547865 TH |
388 | */ |
389 | while (true) { | |
390 | struct blkcg *pos = blkcg; | |
391 | struct blkcg *parent = blkcg_parent(blkcg); | |
beea9da0 DZ |
392 | struct blkcg_gq *ret_blkg = q->root_blkg; |
393 | ||
394 | while (parent) { | |
79fcc5be | 395 | blkg = blkg_lookup(parent, q); |
beea9da0 DZ |
396 | if (blkg) { |
397 | /* remember closest blkg */ | |
398 | ret_blkg = blkg; | |
399 | break; | |
400 | } | |
3c547865 TH |
401 | pos = parent; |
402 | parent = blkcg_parent(parent); | |
403 | } | |
404 | ||
99e60387 | 405 | blkg = blkg_create(pos, disk, NULL); |
8c546287 CH |
406 | if (IS_ERR(blkg)) { |
407 | blkg = ret_blkg; | |
408 | break; | |
409 | } | |
beea9da0 | 410 | if (pos == blkcg) |
8c546287 | 411 | break; |
b978962a DZ |
412 | } |
413 | ||
8c546287 CH |
414 | found: |
415 | spin_unlock_irqrestore(&q->queue_lock, flags); | |
b978962a DZ |
416 | return blkg; |
417 | } | |
418 | ||
3c798398 | 419 | static void blkg_destroy(struct blkcg_gq *blkg) |
03aa264a | 420 | { |
3c798398 | 421 | struct blkcg *blkcg = blkg->blkcg; |
6b065462 | 422 | int i; |
03aa264a | 423 | |
0d945c1f | 424 | lockdep_assert_held(&blkg->q->queue_lock); |
9f13ef67 | 425 | lockdep_assert_held(&blkcg->lock); |
03aa264a TH |
426 | |
427 | /* Something wrong if we are trying to remove same group twice */ | |
e8989fae | 428 | WARN_ON_ONCE(list_empty(&blkg->q_node)); |
9f13ef67 | 429 | WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node)); |
a637120e | 430 | |
6b065462 DZF |
431 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
432 | struct blkcg_policy *pol = blkcg_policy[i]; | |
433 | ||
434 | if (blkg->pd[i] && pol->pd_offline_fn) | |
435 | pol->pd_offline_fn(blkg->pd[i]); | |
436 | } | |
437 | ||
f427d909 TH |
438 | blkg->online = false; |
439 | ||
a637120e | 440 | radix_tree_delete(&blkcg->blkg_tree, blkg->q->id); |
e8989fae | 441 | list_del_init(&blkg->q_node); |
9f13ef67 | 442 | hlist_del_init_rcu(&blkg->blkcg_node); |
03aa264a | 443 | |
a637120e TH |
444 | /* |
445 | * Both setting lookup hint to and clearing it from @blkg are done | |
446 | * under queue_lock. If it's not pointing to @blkg now, it never | |
447 | * will. Hint assignment itself can race safely. | |
448 | */ | |
ec6c676a | 449 | if (rcu_access_pointer(blkcg->blkg_hint) == blkg) |
a637120e TH |
450 | rcu_assign_pointer(blkcg->blkg_hint, NULL); |
451 | ||
03aa264a TH |
452 | /* |
453 | * Put the reference taken at the time of creation so that when all | |
454 | * queues are gone, group can be destroyed. | |
455 | */ | |
7fcf2b03 | 456 | percpu_ref_kill(&blkg->refcnt); |
03aa264a TH |
457 | } |
458 | ||
00ad6991 | 459 | static void blkg_destroy_all(struct gendisk *disk) |
72e06c25 | 460 | { |
00ad6991 | 461 | struct request_queue *q = disk->queue; |
3c798398 | 462 | struct blkcg_gq *blkg, *n; |
a731763f | 463 | int count = BLKG_DESTROY_BATCH_SIZE; |
72e06c25 | 464 | |
a731763f | 465 | restart: |
0d945c1f | 466 | spin_lock_irq(&q->queue_lock); |
9f13ef67 | 467 | list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) { |
3c798398 | 468 | struct blkcg *blkcg = blkg->blkcg; |
72e06c25 | 469 | |
9f13ef67 TH |
470 | spin_lock(&blkcg->lock); |
471 | blkg_destroy(blkg); | |
472 | spin_unlock(&blkcg->lock); | |
a731763f YK |
473 | |
474 | /* | |
475 | * in order to avoid holding the spin lock for too long, release | |
476 | * it when a batch of blkgs are destroyed. | |
477 | */ | |
478 | if (!(--count)) { | |
479 | count = BLKG_DESTROY_BATCH_SIZE; | |
480 | spin_unlock_irq(&q->queue_lock); | |
481 | cond_resched(); | |
482 | goto restart; | |
483 | } | |
72e06c25 | 484 | } |
6fe810bd TH |
485 | |
486 | q->root_blkg = NULL; | |
0d945c1f | 487 | spin_unlock_irq(&q->queue_lock); |
72e06c25 TH |
488 | } |
489 | ||
182446d0 TH |
490 | static int blkcg_reset_stats(struct cgroup_subsys_state *css, |
491 | struct cftype *cftype, u64 val) | |
303a3acb | 492 | { |
182446d0 | 493 | struct blkcg *blkcg = css_to_blkcg(css); |
3c798398 | 494 | struct blkcg_gq *blkg; |
f7331648 | 495 | int i, cpu; |
303a3acb | 496 | |
838f13bf | 497 | mutex_lock(&blkcg_pol_mutex); |
303a3acb | 498 | spin_lock_irq(&blkcg->lock); |
997a026c TH |
499 | |
500 | /* | |
501 | * Note that stat reset is racy - it doesn't synchronize against | |
502 | * stat updates. This is a debug feature which shouldn't exist | |
503 | * anyway. If you get hit by a race, retry. | |
504 | */ | |
b67bfe0d | 505 | hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { |
f7331648 TH |
506 | for_each_possible_cpu(cpu) { |
507 | struct blkg_iostat_set *bis = | |
508 | per_cpu_ptr(blkg->iostat_cpu, cpu); | |
509 | memset(bis, 0, sizeof(*bis)); | |
510 | } | |
511 | memset(&blkg->iostat, 0, sizeof(blkg->iostat)); | |
77ea7338 | 512 | |
8bd435b3 | 513 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
3c798398 | 514 | struct blkcg_policy *pol = blkcg_policy[i]; |
549d3aa8 | 515 | |
a9520cd6 TH |
516 | if (blkg->pd[i] && pol->pd_reset_stats_fn) |
517 | pol->pd_reset_stats_fn(blkg->pd[i]); | |
bc0d6501 | 518 | } |
303a3acb | 519 | } |
f0bdc8cd | 520 | |
303a3acb | 521 | spin_unlock_irq(&blkcg->lock); |
bc0d6501 | 522 | mutex_unlock(&blkcg_pol_mutex); |
303a3acb DS |
523 | return 0; |
524 | } | |
525 | ||
dd165eb3 | 526 | const char *blkg_dev_name(struct blkcg_gq *blkg) |
303a3acb | 527 | { |
d152c682 | 528 | if (!blkg->q->disk || !blkg->q->disk->bdi->dev) |
edb0872f | 529 | return NULL; |
d152c682 | 530 | return bdi_dev_name(blkg->q->disk->bdi); |
303a3acb DS |
531 | } |
532 | ||
d3d32e69 TH |
533 | /** |
534 | * blkcg_print_blkgs - helper for printing per-blkg data | |
535 | * @sf: seq_file to print to | |
536 | * @blkcg: blkcg of interest | |
537 | * @prfill: fill function to print out a blkg | |
538 | * @pol: policy in question | |
539 | * @data: data to be passed to @prfill | |
540 | * @show_total: to print out sum of prfill return values or not | |
541 | * | |
542 | * This function invokes @prfill on each blkg of @blkcg if pd for the | |
543 | * policy specified by @pol exists. @prfill is invoked with @sf, the | |
810ecfa7 TH |
544 | * policy data and @data and the matching queue lock held. If @show_total |
545 | * is %true, the sum of the return values from @prfill is printed with | |
546 | * "Total" label at the end. | |
d3d32e69 TH |
547 | * |
548 | * This is to be used to construct print functions for | |
549 | * cftype->read_seq_string method. | |
550 | */ | |
3c798398 | 551 | void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, |
f95a04af TH |
552 | u64 (*prfill)(struct seq_file *, |
553 | struct blkg_policy_data *, int), | |
3c798398 | 554 | const struct blkcg_policy *pol, int data, |
ec399347 | 555 | bool show_total) |
5624a4e4 | 556 | { |
3c798398 | 557 | struct blkcg_gq *blkg; |
d3d32e69 | 558 | u64 total = 0; |
5624a4e4 | 559 | |
810ecfa7 | 560 | rcu_read_lock(); |
ee89f812 | 561 | hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { |
0d945c1f | 562 | spin_lock_irq(&blkg->q->queue_lock); |
a2b1693b | 563 | if (blkcg_policy_enabled(blkg->q, pol)) |
f95a04af | 564 | total += prfill(sf, blkg->pd[pol->plid], data); |
0d945c1f | 565 | spin_unlock_irq(&blkg->q->queue_lock); |
810ecfa7 TH |
566 | } |
567 | rcu_read_unlock(); | |
d3d32e69 TH |
568 | |
569 | if (show_total) | |
570 | seq_printf(sf, "Total %llu\n", (unsigned long long)total); | |
571 | } | |
829fdb50 | 572 | EXPORT_SYMBOL_GPL(blkcg_print_blkgs); |
d3d32e69 TH |
573 | |
574 | /** | |
575 | * __blkg_prfill_u64 - prfill helper for a single u64 value | |
576 | * @sf: seq_file to print to | |
f95a04af | 577 | * @pd: policy private data of interest |
d3d32e69 TH |
578 | * @v: value to print |
579 | * | |
f95a04af | 580 | * Print @v to @sf for the device assocaited with @pd. |
d3d32e69 | 581 | */ |
f95a04af | 582 | u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v) |
d3d32e69 | 583 | { |
f95a04af | 584 | const char *dname = blkg_dev_name(pd->blkg); |
d3d32e69 TH |
585 | |
586 | if (!dname) | |
587 | return 0; | |
588 | ||
589 | seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v); | |
590 | return v; | |
591 | } | |
829fdb50 | 592 | EXPORT_SYMBOL_GPL(__blkg_prfill_u64); |
d3d32e69 | 593 | |
015d254c | 594 | /** |
22ae8ce8 | 595 | * blkcg_conf_open_bdev - parse and open bdev for per-blkg config update |
015d254c TH |
596 | * @inputp: input string pointer |
597 | * | |
598 | * Parse the device node prefix part, MAJ:MIN, of per-blkg config update | |
22ae8ce8 | 599 | * from @input and get and return the matching bdev. *@inputp is |
015d254c TH |
600 | * updated to point past the device node prefix. Returns an ERR_PTR() |
601 | * value on error. | |
602 | * | |
603 | * Use this function iff blkg_conf_prep() can't be used for some reason. | |
604 | */ | |
22ae8ce8 | 605 | struct block_device *blkcg_conf_open_bdev(char **inputp) |
015d254c TH |
606 | { |
607 | char *input = *inputp; | |
608 | unsigned int major, minor; | |
22ae8ce8 CH |
609 | struct block_device *bdev; |
610 | int key_len; | |
015d254c TH |
611 | |
612 | if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2) | |
613 | return ERR_PTR(-EINVAL); | |
614 | ||
615 | input += key_len; | |
616 | if (!isspace(*input)) | |
617 | return ERR_PTR(-EINVAL); | |
618 | input = skip_spaces(input); | |
619 | ||
22ae8ce8 CH |
620 | bdev = blkdev_get_no_open(MKDEV(major, minor)); |
621 | if (!bdev) | |
015d254c | 622 | return ERR_PTR(-ENODEV); |
22ae8ce8 CH |
623 | if (bdev_is_partition(bdev)) { |
624 | blkdev_put_no_open(bdev); | |
015d254c TH |
625 | return ERR_PTR(-ENODEV); |
626 | } | |
627 | ||
628 | *inputp = input; | |
22ae8ce8 | 629 | return bdev; |
015d254c TH |
630 | } |
631 | ||
3a8b31d3 TH |
632 | /** |
633 | * blkg_conf_prep - parse and prepare for per-blkg config update | |
634 | * @blkcg: target block cgroup | |
da8b0662 | 635 | * @pol: target policy |
3a8b31d3 TH |
636 | * @input: input string |
637 | * @ctx: blkg_conf_ctx to be filled | |
638 | * | |
639 | * Parse per-blkg config update from @input and initialize @ctx with the | |
36aa9e5f TH |
640 | * result. @ctx->blkg points to the blkg to be updated and @ctx->body the |
641 | * part of @input following MAJ:MIN. This function returns with RCU read | |
642 | * lock and queue lock held and must be paired with blkg_conf_finish(). | |
3a8b31d3 | 643 | */ |
3c798398 | 644 | int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, |
36aa9e5f | 645 | char *input, struct blkg_conf_ctx *ctx) |
ed6cddef | 646 | __acquires(rcu) __acquires(&bdev->bd_queue->queue_lock) |
34d0f179 | 647 | { |
22ae8ce8 | 648 | struct block_device *bdev; |
99e60387 | 649 | struct gendisk *disk; |
457e490f | 650 | struct request_queue *q; |
3c798398 | 651 | struct blkcg_gq *blkg; |
015d254c | 652 | int ret; |
36aa9e5f | 653 | |
22ae8ce8 CH |
654 | bdev = blkcg_conf_open_bdev(&input); |
655 | if (IS_ERR(bdev)) | |
656 | return PTR_ERR(bdev); | |
99e60387 CH |
657 | disk = bdev->bd_disk; |
658 | q = disk->queue; | |
da8b0662 | 659 | |
0c9d338c YK |
660 | /* |
661 | * blkcg_deactivate_policy() requires queue to be frozen, we can grab | |
662 | * q_usage_counter to prevent concurrent with blkcg_deactivate_policy(). | |
663 | */ | |
664 | ret = blk_queue_enter(q, 0); | |
665 | if (ret) | |
15c30104 | 666 | goto fail; |
0c9d338c | 667 | |
457e490f | 668 | rcu_read_lock(); |
0d945c1f | 669 | spin_lock_irq(&q->queue_lock); |
e56da7e2 | 670 | |
f753526e CH |
671 | if (!blkcg_policy_enabled(q, pol)) { |
672 | ret = -EOPNOTSUPP; | |
457e490f TE |
673 | goto fail_unlock; |
674 | } | |
675 | ||
f753526e | 676 | blkg = blkg_lookup(blkcg, q); |
5765033c | 677 | if (blkg) |
457e490f TE |
678 | goto success; |
679 | ||
680 | /* | |
681 | * Create blkgs walking down from blkcg_root to @blkcg, so that all | |
682 | * non-root blkgs have access to their parents. | |
683 | */ | |
684 | while (true) { | |
685 | struct blkcg *pos = blkcg; | |
686 | struct blkcg *parent; | |
687 | struct blkcg_gq *new_blkg; | |
688 | ||
689 | parent = blkcg_parent(blkcg); | |
79fcc5be | 690 | while (parent && !blkg_lookup(parent, q)) { |
457e490f TE |
691 | pos = parent; |
692 | parent = blkcg_parent(parent); | |
693 | } | |
694 | ||
695 | /* Drop locks to do new blkg allocation with GFP_KERNEL. */ | |
0d945c1f | 696 | spin_unlock_irq(&q->queue_lock); |
3a8b31d3 | 697 | rcu_read_unlock(); |
457e490f | 698 | |
99e60387 | 699 | new_blkg = blkg_alloc(pos, disk, GFP_KERNEL); |
457e490f TE |
700 | if (unlikely(!new_blkg)) { |
701 | ret = -ENOMEM; | |
15c30104 | 702 | goto fail_exit_queue; |
7702e8f4 | 703 | } |
3a8b31d3 | 704 | |
f255c19b GKB |
705 | if (radix_tree_preload(GFP_KERNEL)) { |
706 | blkg_free(new_blkg); | |
707 | ret = -ENOMEM; | |
15c30104 | 708 | goto fail_exit_queue; |
f255c19b GKB |
709 | } |
710 | ||
457e490f | 711 | rcu_read_lock(); |
0d945c1f | 712 | spin_lock_irq(&q->queue_lock); |
457e490f | 713 | |
f753526e | 714 | if (!blkcg_policy_enabled(q, pol)) { |
52abfcbd | 715 | blkg_free(new_blkg); |
f753526e | 716 | ret = -EOPNOTSUPP; |
f255c19b | 717 | goto fail_preloaded; |
457e490f TE |
718 | } |
719 | ||
f753526e | 720 | blkg = blkg_lookup(pos, q); |
457e490f TE |
721 | if (blkg) { |
722 | blkg_free(new_blkg); | |
723 | } else { | |
99e60387 | 724 | blkg = blkg_create(pos, disk, new_blkg); |
98d669b4 | 725 | if (IS_ERR(blkg)) { |
457e490f | 726 | ret = PTR_ERR(blkg); |
f255c19b | 727 | goto fail_preloaded; |
457e490f TE |
728 | } |
729 | } | |
730 | ||
f255c19b GKB |
731 | radix_tree_preload_end(); |
732 | ||
457e490f TE |
733 | if (pos == blkcg) |
734 | goto success; | |
735 | } | |
736 | success: | |
0c9d338c | 737 | blk_queue_exit(q); |
22ae8ce8 | 738 | ctx->bdev = bdev; |
3a8b31d3 | 739 | ctx->blkg = blkg; |
015d254c | 740 | ctx->body = input; |
726fa694 | 741 | return 0; |
457e490f | 742 | |
f255c19b GKB |
743 | fail_preloaded: |
744 | radix_tree_preload_end(); | |
457e490f | 745 | fail_unlock: |
0d945c1f | 746 | spin_unlock_irq(&q->queue_lock); |
457e490f | 747 | rcu_read_unlock(); |
15c30104 YK |
748 | fail_exit_queue: |
749 | blk_queue_exit(q); | |
457e490f | 750 | fail: |
22ae8ce8 | 751 | blkdev_put_no_open(bdev); |
457e490f TE |
752 | /* |
753 | * If queue was bypassing, we should retry. Do so after a | |
754 | * short msleep(). It isn't strictly necessary but queue | |
755 | * can be bypassing for some time and it's always nice to | |
756 | * avoid busy looping. | |
757 | */ | |
758 | if (ret == -EBUSY) { | |
759 | msleep(10); | |
760 | ret = restart_syscall(); | |
761 | } | |
762 | return ret; | |
34d0f179 | 763 | } |
89f3b6d6 | 764 | EXPORT_SYMBOL_GPL(blkg_conf_prep); |
34d0f179 | 765 | |
3a8b31d3 TH |
766 | /** |
767 | * blkg_conf_finish - finish up per-blkg config update | |
768 | * @ctx: blkg_conf_ctx intiailized by blkg_conf_prep() | |
769 | * | |
770 | * Finish up after per-blkg config update. This function must be paired | |
771 | * with blkg_conf_prep(). | |
772 | */ | |
829fdb50 | 773 | void blkg_conf_finish(struct blkg_conf_ctx *ctx) |
ed6cddef | 774 | __releases(&ctx->bdev->bd_queue->queue_lock) __releases(rcu) |
34d0f179 | 775 | { |
ed6cddef | 776 | spin_unlock_irq(&bdev_get_queue(ctx->bdev)->queue_lock); |
3a8b31d3 | 777 | rcu_read_unlock(); |
22ae8ce8 | 778 | blkdev_put_no_open(ctx->bdev); |
34d0f179 | 779 | } |
89f3b6d6 | 780 | EXPORT_SYMBOL_GPL(blkg_conf_finish); |
34d0f179 | 781 | |
cd1fc4b9 BB |
782 | static void blkg_iostat_set(struct blkg_iostat *dst, struct blkg_iostat *src) |
783 | { | |
784 | int i; | |
785 | ||
786 | for (i = 0; i < BLKG_IOSTAT_NR; i++) { | |
787 | dst->bytes[i] = src->bytes[i]; | |
788 | dst->ios[i] = src->ios[i]; | |
789 | } | |
790 | } | |
791 | ||
792 | static void blkg_iostat_add(struct blkg_iostat *dst, struct blkg_iostat *src) | |
793 | { | |
794 | int i; | |
795 | ||
796 | for (i = 0; i < BLKG_IOSTAT_NR; i++) { | |
797 | dst->bytes[i] += src->bytes[i]; | |
798 | dst->ios[i] += src->ios[i]; | |
799 | } | |
800 | } | |
801 | ||
802 | static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src) | |
803 | { | |
804 | int i; | |
805 | ||
806 | for (i = 0; i < BLKG_IOSTAT_NR; i++) { | |
807 | dst->bytes[i] -= src->bytes[i]; | |
808 | dst->ios[i] -= src->ios[i]; | |
809 | } | |
810 | } | |
811 | ||
362b8c16 JY |
812 | static void blkcg_iostat_update(struct blkcg_gq *blkg, struct blkg_iostat *cur, |
813 | struct blkg_iostat *last) | |
814 | { | |
815 | struct blkg_iostat delta; | |
816 | unsigned long flags; | |
817 | ||
818 | /* propagate percpu delta to global */ | |
819 | flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync); | |
820 | blkg_iostat_set(&delta, cur); | |
821 | blkg_iostat_sub(&delta, last); | |
822 | blkg_iostat_add(&blkg->iostat.cur, &delta); | |
823 | blkg_iostat_add(last, &delta); | |
824 | u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags); | |
825 | } | |
826 | ||
cd1fc4b9 BB |
827 | static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu) |
828 | { | |
829 | struct blkcg *blkcg = css_to_blkcg(css); | |
830 | struct blkcg_gq *blkg; | |
831 | ||
dc26532a JW |
832 | /* Root-level stats are sourced from system-wide IO stats */ |
833 | if (!cgroup_parent(css->cgroup)) | |
834 | return; | |
835 | ||
cd1fc4b9 BB |
836 | rcu_read_lock(); |
837 | ||
838 | hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { | |
839 | struct blkcg_gq *parent = blkg->parent; | |
840 | struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu); | |
362b8c16 | 841 | struct blkg_iostat cur; |
cd1fc4b9 BB |
842 | unsigned int seq; |
843 | ||
844 | /* fetch the current per-cpu values */ | |
845 | do { | |
846 | seq = u64_stats_fetch_begin(&bisc->sync); | |
847 | blkg_iostat_set(&cur, &bisc->cur); | |
848 | } while (u64_stats_fetch_retry(&bisc->sync, seq)); | |
849 | ||
362b8c16 | 850 | blkcg_iostat_update(blkg, &cur, &bisc->last); |
cd1fc4b9 | 851 | |
dc26532a | 852 | /* propagate global delta to parent (unless that's root) */ |
362b8c16 JY |
853 | if (parent && parent->parent) |
854 | blkcg_iostat_update(parent, &blkg->iostat.cur, | |
855 | &blkg->iostat.last); | |
cd1fc4b9 BB |
856 | } |
857 | ||
858 | rcu_read_unlock(); | |
859 | } | |
860 | ||
ef45fe47 | 861 | /* |
dc26532a JW |
862 | * We source root cgroup stats from the system-wide stats to avoid |
863 | * tracking the same information twice and incurring overhead when no | |
864 | * cgroups are defined. For that reason, cgroup_rstat_flush in | |
865 | * blkcg_print_stat does not actually fill out the iostat in the root | |
866 | * cgroup's blkcg_gq. | |
ef45fe47 BB |
867 | * |
868 | * However, we would like to re-use the printing code between the root and | |
869 | * non-root cgroups to the extent possible. For that reason, we simulate | |
870 | * flushing the root cgroup's stats by explicitly filling in the iostat | |
871 | * with disk level statistics. | |
872 | */ | |
873 | static void blkcg_fill_root_iostats(void) | |
874 | { | |
875 | struct class_dev_iter iter; | |
876 | struct device *dev; | |
877 | ||
878 | class_dev_iter_init(&iter, &block_class, NULL, &disk_type); | |
879 | while ((dev = class_dev_iter_next(&iter))) { | |
0d02129e | 880 | struct block_device *bdev = dev_to_bdev(dev); |
928f6f00 | 881 | struct blkcg_gq *blkg = bdev->bd_disk->queue->root_blkg; |
ef45fe47 BB |
882 | struct blkg_iostat tmp; |
883 | int cpu; | |
f122d103 | 884 | unsigned long flags; |
ef45fe47 BB |
885 | |
886 | memset(&tmp, 0, sizeof(tmp)); | |
887 | for_each_possible_cpu(cpu) { | |
888 | struct disk_stats *cpu_dkstats; | |
889 | ||
0d02129e | 890 | cpu_dkstats = per_cpu_ptr(bdev->bd_stats, cpu); |
ef45fe47 BB |
891 | tmp.ios[BLKG_IOSTAT_READ] += |
892 | cpu_dkstats->ios[STAT_READ]; | |
893 | tmp.ios[BLKG_IOSTAT_WRITE] += | |
894 | cpu_dkstats->ios[STAT_WRITE]; | |
895 | tmp.ios[BLKG_IOSTAT_DISCARD] += | |
896 | cpu_dkstats->ios[STAT_DISCARD]; | |
897 | // convert sectors to bytes | |
898 | tmp.bytes[BLKG_IOSTAT_READ] += | |
899 | cpu_dkstats->sectors[STAT_READ] << 9; | |
900 | tmp.bytes[BLKG_IOSTAT_WRITE] += | |
901 | cpu_dkstats->sectors[STAT_WRITE] << 9; | |
902 | tmp.bytes[BLKG_IOSTAT_DISCARD] += | |
903 | cpu_dkstats->sectors[STAT_DISCARD] << 9; | |
ef45fe47 | 904 | } |
f122d103 CZ |
905 | |
906 | flags = u64_stats_update_begin_irqsave(&blkg->iostat.sync); | |
907 | blkg_iostat_set(&blkg->iostat.cur, &tmp); | |
908 | u64_stats_update_end_irqrestore(&blkg->iostat.sync, flags); | |
ef45fe47 BB |
909 | } |
910 | } | |
911 | ||
49cb5168 | 912 | static void blkcg_print_one_stat(struct blkcg_gq *blkg, struct seq_file *s) |
2ee867dc | 913 | { |
49cb5168 CH |
914 | struct blkg_iostat_set *bis = &blkg->iostat; |
915 | u64 rbytes, wbytes, rios, wios, dbytes, dios; | |
49cb5168 CH |
916 | const char *dname; |
917 | unsigned seq; | |
49cb5168 | 918 | int i; |
ef45fe47 | 919 | |
49cb5168 CH |
920 | if (!blkg->online) |
921 | return; | |
2ee867dc | 922 | |
49cb5168 CH |
923 | dname = blkg_dev_name(blkg); |
924 | if (!dname) | |
925 | return; | |
2ee867dc | 926 | |
252c651a | 927 | seq_printf(s, "%s ", dname); |
b0814361 | 928 | |
49cb5168 CH |
929 | do { |
930 | seq = u64_stats_fetch_begin(&bis->sync); | |
b0814361 | 931 | |
49cb5168 CH |
932 | rbytes = bis->cur.bytes[BLKG_IOSTAT_READ]; |
933 | wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE]; | |
934 | dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD]; | |
935 | rios = bis->cur.ios[BLKG_IOSTAT_READ]; | |
936 | wios = bis->cur.ios[BLKG_IOSTAT_WRITE]; | |
937 | dios = bis->cur.ios[BLKG_IOSTAT_DISCARD]; | |
938 | } while (u64_stats_fetch_retry(&bis->sync, seq)); | |
2ee867dc | 939 | |
49cb5168 | 940 | if (rbytes || wbytes || rios || wios) { |
252c651a | 941 | seq_printf(s, "rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu", |
49cb5168 CH |
942 | rbytes, wbytes, rios, wios, |
943 | dbytes, dios); | |
944 | } | |
903d23f0 | 945 | |
49cb5168 | 946 | if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) { |
252c651a | 947 | seq_printf(s, " use_delay=%d delay_nsec=%llu", |
49cb5168 CH |
948 | atomic_read(&blkg->use_delay), |
949 | atomic64_read(&blkg->delay_nsec)); | |
950 | } | |
2ee867dc | 951 | |
49cb5168 CH |
952 | for (i = 0; i < BLKCG_MAX_POLS; i++) { |
953 | struct blkcg_policy *pol = blkcg_policy[i]; | |
2ee867dc | 954 | |
49cb5168 CH |
955 | if (!blkg->pd[i] || !pol->pd_stat_fn) |
956 | continue; | |
903d23f0 | 957 | |
3607849d | 958 | pol->pd_stat_fn(blkg->pd[i], s); |
49cb5168 | 959 | } |
d09d8df3 | 960 | |
3607849d | 961 | seq_puts(s, "\n"); |
49cb5168 | 962 | } |
903d23f0 | 963 | |
49cb5168 CH |
964 | static int blkcg_print_stat(struct seq_file *sf, void *v) |
965 | { | |
966 | struct blkcg *blkcg = css_to_blkcg(seq_css(sf)); | |
967 | struct blkcg_gq *blkg; | |
903d23f0 | 968 | |
49cb5168 CH |
969 | if (!seq_css(sf)->parent) |
970 | blkcg_fill_root_iostats(); | |
971 | else | |
972 | cgroup_rstat_flush(blkcg->css.cgroup); | |
07b0fdec | 973 | |
49cb5168 CH |
974 | rcu_read_lock(); |
975 | hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) { | |
976 | spin_lock_irq(&blkg->q->queue_lock); | |
977 | blkcg_print_one_stat(blkg, sf); | |
b0814361 | 978 | spin_unlock_irq(&blkg->q->queue_lock); |
2ee867dc | 979 | } |
2ee867dc TH |
980 | rcu_read_unlock(); |
981 | return 0; | |
982 | } | |
983 | ||
e1f3b941 | 984 | static struct cftype blkcg_files[] = { |
2ee867dc TH |
985 | { |
986 | .name = "stat", | |
987 | .seq_show = blkcg_print_stat, | |
988 | }, | |
989 | { } /* terminate */ | |
990 | }; | |
991 | ||
e1f3b941 | 992 | static struct cftype blkcg_legacy_files[] = { |
84c124da DS |
993 | { |
994 | .name = "reset_stats", | |
3c798398 | 995 | .write_u64 = blkcg_reset_stats, |
22084190 | 996 | }, |
4baf6e33 | 997 | { } /* terminate */ |
31e4c28d VG |
998 | }; |
999 | ||
dec223c9 CH |
1000 | #ifdef CONFIG_CGROUP_WRITEBACK |
1001 | struct list_head *blkcg_get_cgwb_list(struct cgroup_subsys_state *css) | |
1002 | { | |
1003 | return &css_to_blkcg(css)->cgwb_list; | |
1004 | } | |
1005 | #endif | |
1006 | ||
59b57717 DZF |
1007 | /* |
1008 | * blkcg destruction is a three-stage process. | |
1009 | * | |
1010 | * 1. Destruction starts. The blkcg_css_offline() callback is invoked | |
1011 | * which offlines writeback. Here we tie the next stage of blkg destruction | |
1012 | * to the completion of writeback associated with the blkcg. This lets us | |
1013 | * avoid punting potentially large amounts of outstanding writeback to root | |
1014 | * while maintaining any ongoing policies. The next stage is triggered when | |
1015 | * the nr_cgwbs count goes to zero. | |
1016 | * | |
1017 | * 2. When the nr_cgwbs count goes to zero, blkcg_destroy_blkgs() is called | |
1018 | * and handles the destruction of blkgs. Here the css reference held by | |
1019 | * the blkg is put back eventually allowing blkcg_css_free() to be called. | |
1020 | * This work may occur in cgwb_release_workfn() on the cgwb_release | |
1021 | * workqueue. Any submitted ios that fail to get the blkg ref will be | |
1022 | * punted to the root_blkg. | |
1023 | * | |
1024 | * 3. Once the blkcg ref count goes to zero, blkcg_css_free() is called. | |
1025 | * This finally frees the blkcg. | |
1026 | */ | |
1027 | ||
59b57717 DZF |
1028 | /** |
1029 | * blkcg_destroy_blkgs - responsible for shooting down blkgs | |
1030 | * @blkcg: blkcg of interest | |
1031 | * | |
1032 | * blkgs should be removed while holding both q and blkcg locks. As blkcg lock | |
1033 | * is nested inside q lock, this function performs reverse double lock dancing. | |
1034 | * Destroying the blkgs releases the reference held on the blkcg's css allowing | |
1035 | * blkcg_css_free to eventually be called. | |
1036 | * | |
1037 | * This is the blkcg counterpart of ioc_release_fn(). | |
1038 | */ | |
397c9f46 | 1039 | static void blkcg_destroy_blkgs(struct blkcg *blkcg) |
59b57717 | 1040 | { |
6c635cae BW |
1041 | might_sleep(); |
1042 | ||
9f13ef67 | 1043 | spin_lock_irq(&blkcg->lock); |
7ee9c562 | 1044 | |
4c699480 JQ |
1045 | while (!hlist_empty(&blkcg->blkg_list)) { |
1046 | struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first, | |
6b065462 | 1047 | struct blkcg_gq, blkcg_node); |
4c699480 JQ |
1048 | struct request_queue *q = blkg->q; |
1049 | ||
6c635cae BW |
1050 | if (need_resched() || !spin_trylock(&q->queue_lock)) { |
1051 | /* | |
1052 | * Given that the system can accumulate a huge number | |
1053 | * of blkgs in pathological cases, check to see if we | |
1054 | * need to rescheduling to avoid softlockup. | |
1055 | */ | |
4c699480 | 1056 | spin_unlock_irq(&blkcg->lock); |
6c635cae | 1057 | cond_resched(); |
4c699480 | 1058 | spin_lock_irq(&blkcg->lock); |
6c635cae | 1059 | continue; |
4c699480 | 1060 | } |
6c635cae BW |
1061 | |
1062 | blkg_destroy(blkg); | |
1063 | spin_unlock(&q->queue_lock); | |
4c699480 | 1064 | } |
6b065462 | 1065 | |
4c699480 JQ |
1066 | spin_unlock_irq(&blkcg->lock); |
1067 | } | |
1068 | ||
397c9f46 CH |
1069 | /** |
1070 | * blkcg_pin_online - pin online state | |
1071 | * @blkcg_css: blkcg of interest | |
1072 | * | |
1073 | * While pinned, a blkcg is kept online. This is primarily used to | |
1074 | * impedance-match blkg and cgwb lifetimes so that blkg doesn't go offline | |
1075 | * while an associated cgwb is still active. | |
1076 | */ | |
1077 | void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css) | |
1078 | { | |
1079 | refcount_inc(&css_to_blkcg(blkcg_css)->online_pin); | |
1080 | } | |
1081 | ||
1082 | /** | |
1083 | * blkcg_unpin_online - unpin online state | |
1084 | * @blkcg_css: blkcg of interest | |
1085 | * | |
1086 | * This is primarily used to impedance-match blkg and cgwb lifetimes so | |
1087 | * that blkg doesn't go offline while an associated cgwb is still active. | |
1088 | * When this count goes to zero, all active cgwbs have finished so the | |
1089 | * blkcg can continue destruction by calling blkcg_destroy_blkgs(). | |
1090 | */ | |
1091 | void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css) | |
1092 | { | |
1093 | struct blkcg *blkcg = css_to_blkcg(blkcg_css); | |
1094 | ||
1095 | do { | |
1096 | if (!refcount_dec_and_test(&blkcg->online_pin)) | |
1097 | break; | |
1098 | blkcg_destroy_blkgs(blkcg); | |
1099 | blkcg = blkcg_parent(blkcg); | |
1100 | } while (blkcg); | |
1101 | } | |
1102 | ||
1103 | /** | |
1104 | * blkcg_css_offline - cgroup css_offline callback | |
1105 | * @css: css of interest | |
1106 | * | |
1107 | * This function is called when @css is about to go away. Here the cgwbs are | |
1108 | * offlined first and only once writeback associated with the blkcg has | |
1109 | * finished do we start step 2 (see above). | |
1110 | */ | |
1111 | static void blkcg_css_offline(struct cgroup_subsys_state *css) | |
1112 | { | |
1113 | /* this prevents anyone from attaching or migrating to this blkcg */ | |
dec223c9 | 1114 | wb_blkcg_offline(css); |
397c9f46 CH |
1115 | |
1116 | /* put the base online pin allowing step 2 to be triggered */ | |
1117 | blkcg_unpin_online(css); | |
1118 | } | |
1119 | ||
eb95419b | 1120 | static void blkcg_css_free(struct cgroup_subsys_state *css) |
7ee9c562 | 1121 | { |
eb95419b | 1122 | struct blkcg *blkcg = css_to_blkcg(css); |
bc915e61 | 1123 | int i; |
7ee9c562 | 1124 | |
7876f930 | 1125 | mutex_lock(&blkcg_pol_mutex); |
e4a9bde9 | 1126 | |
7876f930 | 1127 | list_del(&blkcg->all_blkcgs_node); |
7876f930 | 1128 | |
bc915e61 | 1129 | for (i = 0; i < BLKCG_MAX_POLS; i++) |
e4a9bde9 TH |
1130 | if (blkcg->cpd[i]) |
1131 | blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); | |
1132 | ||
1133 | mutex_unlock(&blkcg_pol_mutex); | |
1134 | ||
bc915e61 | 1135 | kfree(blkcg); |
31e4c28d VG |
1136 | } |
1137 | ||
eb95419b TH |
1138 | static struct cgroup_subsys_state * |
1139 | blkcg_css_alloc(struct cgroup_subsys_state *parent_css) | |
31e4c28d | 1140 | { |
3c798398 | 1141 | struct blkcg *blkcg; |
e48453c3 AA |
1142 | struct cgroup_subsys_state *ret; |
1143 | int i; | |
31e4c28d | 1144 | |
7876f930 TH |
1145 | mutex_lock(&blkcg_pol_mutex); |
1146 | ||
eb95419b | 1147 | if (!parent_css) { |
3c798398 | 1148 | blkcg = &blkcg_root; |
bc915e61 TH |
1149 | } else { |
1150 | blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); | |
1151 | if (!blkcg) { | |
1152 | ret = ERR_PTR(-ENOMEM); | |
4c18c9e9 | 1153 | goto unlock; |
bc915e61 | 1154 | } |
e48453c3 AA |
1155 | } |
1156 | ||
1157 | for (i = 0; i < BLKCG_MAX_POLS ; i++) { | |
1158 | struct blkcg_policy *pol = blkcg_policy[i]; | |
1159 | struct blkcg_policy_data *cpd; | |
1160 | ||
1161 | /* | |
1162 | * If the policy hasn't been attached yet, wait for it | |
1163 | * to be attached before doing anything else. Otherwise, | |
1164 | * check if the policy requires any specific per-cgroup | |
1165 | * data: if it does, allocate and initialize it. | |
1166 | */ | |
e4a9bde9 | 1167 | if (!pol || !pol->cpd_alloc_fn) |
e48453c3 AA |
1168 | continue; |
1169 | ||
e4a9bde9 | 1170 | cpd = pol->cpd_alloc_fn(GFP_KERNEL); |
e48453c3 AA |
1171 | if (!cpd) { |
1172 | ret = ERR_PTR(-ENOMEM); | |
1173 | goto free_pd_blkcg; | |
1174 | } | |
81437648 TH |
1175 | blkcg->cpd[i] = cpd; |
1176 | cpd->blkcg = blkcg; | |
e48453c3 | 1177 | cpd->plid = i; |
e4a9bde9 TH |
1178 | if (pol->cpd_init_fn) |
1179 | pol->cpd_init_fn(cpd); | |
e48453c3 | 1180 | } |
31e4c28d | 1181 | |
31e4c28d | 1182 | spin_lock_init(&blkcg->lock); |
d866dbf6 | 1183 | refcount_set(&blkcg->online_pin, 1); |
e00f4f4d | 1184 | INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN); |
31e4c28d | 1185 | INIT_HLIST_HEAD(&blkcg->blkg_list); |
52ebea74 TH |
1186 | #ifdef CONFIG_CGROUP_WRITEBACK |
1187 | INIT_LIST_HEAD(&blkcg->cgwb_list); | |
1188 | #endif | |
7876f930 TH |
1189 | list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs); |
1190 | ||
1191 | mutex_unlock(&blkcg_pol_mutex); | |
31e4c28d | 1192 | return &blkcg->css; |
e48453c3 AA |
1193 | |
1194 | free_pd_blkcg: | |
1195 | for (i--; i >= 0; i--) | |
e4a9bde9 TH |
1196 | if (blkcg->cpd[i]) |
1197 | blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); | |
4c18c9e9 | 1198 | |
1199 | if (blkcg != &blkcg_root) | |
1200 | kfree(blkcg); | |
1201 | unlock: | |
7876f930 | 1202 | mutex_unlock(&blkcg_pol_mutex); |
e48453c3 | 1203 | return ret; |
31e4c28d VG |
1204 | } |
1205 | ||
4308a434 TH |
1206 | static int blkcg_css_online(struct cgroup_subsys_state *css) |
1207 | { | |
397c9f46 | 1208 | struct blkcg *parent = blkcg_parent(css_to_blkcg(css)); |
4308a434 TH |
1209 | |
1210 | /* | |
1211 | * blkcg_pin_online() is used to delay blkcg offline so that blkgs | |
1212 | * don't go offline while cgwbs are still active on them. Pin the | |
1213 | * parent so that offline always happens towards the root. | |
1214 | */ | |
1215 | if (parent) | |
397c9f46 | 1216 | blkcg_pin_online(css); |
4308a434 TH |
1217 | return 0; |
1218 | } | |
1219 | ||
9823538f | 1220 | int blkcg_init_disk(struct gendisk *disk) |
5efd6113 | 1221 | { |
9823538f | 1222 | struct request_queue *q = disk->queue; |
d708f0d5 JA |
1223 | struct blkcg_gq *new_blkg, *blkg; |
1224 | bool preloaded; | |
ec13b1d6 TH |
1225 | int ret; |
1226 | ||
472e4314 ML |
1227 | INIT_LIST_HEAD(&q->blkg_list); |
1228 | ||
99e60387 | 1229 | new_blkg = blkg_alloc(&blkcg_root, disk, GFP_KERNEL); |
d708f0d5 JA |
1230 | if (!new_blkg) |
1231 | return -ENOMEM; | |
1232 | ||
1233 | preloaded = !radix_tree_preload(GFP_KERNEL); | |
1234 | ||
bea54883 | 1235 | /* Make sure the root blkg exists. */ |
77c570a1 | 1236 | /* spin_lock_irq can serve as RCU read-side critical section. */ |
0d945c1f | 1237 | spin_lock_irq(&q->queue_lock); |
99e60387 | 1238 | blkg = blkg_create(&blkcg_root, disk, new_blkg); |
901932a3 JB |
1239 | if (IS_ERR(blkg)) |
1240 | goto err_unlock; | |
1241 | q->root_blkg = blkg; | |
0d945c1f | 1242 | spin_unlock_irq(&q->queue_lock); |
ec13b1d6 | 1243 | |
d708f0d5 JA |
1244 | if (preloaded) |
1245 | radix_tree_preload_end(); | |
1246 | ||
b0dde3f5 | 1247 | ret = blk_ioprio_init(disk); |
556910e3 BVA |
1248 | if (ret) |
1249 | goto err_destroy_all; | |
1250 | ||
e13793ba | 1251 | ret = blk_throtl_init(disk); |
19688d7f | 1252 | if (ret) |
33dc6279 | 1253 | goto err_ioprio_exit; |
19688d7f | 1254 | |
16fac1b5 | 1255 | ret = blk_iolatency_init(disk); |
33dc6279 CH |
1256 | if (ret) |
1257 | goto err_throtl_exit; | |
6f5ddde4 | 1258 | |
04be60b5 | 1259 | return 0; |
901932a3 | 1260 | |
33dc6279 | 1261 | err_throtl_exit: |
e13793ba | 1262 | blk_throtl_exit(disk); |
33dc6279 | 1263 | err_ioprio_exit: |
b0dde3f5 | 1264 | blk_ioprio_exit(disk); |
04be60b5 | 1265 | err_destroy_all: |
00ad6991 | 1266 | blkg_destroy_all(disk); |
04be60b5 | 1267 | return ret; |
901932a3 | 1268 | err_unlock: |
0d945c1f | 1269 | spin_unlock_irq(&q->queue_lock); |
901932a3 JB |
1270 | if (preloaded) |
1271 | radix_tree_preload_end(); | |
1272 | return PTR_ERR(blkg); | |
5efd6113 TH |
1273 | } |
1274 | ||
9823538f | 1275 | void blkcg_exit_disk(struct gendisk *disk) |
5efd6113 | 1276 | { |
00ad6991 | 1277 | blkg_destroy_all(disk); |
e13793ba | 1278 | blk_throtl_exit(disk); |
5efd6113 TH |
1279 | } |
1280 | ||
69d7fde5 TH |
1281 | static void blkcg_bind(struct cgroup_subsys_state *root_css) |
1282 | { | |
1283 | int i; | |
1284 | ||
1285 | mutex_lock(&blkcg_pol_mutex); | |
1286 | ||
1287 | for (i = 0; i < BLKCG_MAX_POLS; i++) { | |
1288 | struct blkcg_policy *pol = blkcg_policy[i]; | |
1289 | struct blkcg *blkcg; | |
1290 | ||
1291 | if (!pol || !pol->cpd_bind_fn) | |
1292 | continue; | |
1293 | ||
1294 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) | |
1295 | if (blkcg->cpd[pol->plid]) | |
1296 | pol->cpd_bind_fn(blkcg->cpd[pol->plid]); | |
1297 | } | |
1298 | mutex_unlock(&blkcg_pol_mutex); | |
1299 | } | |
1300 | ||
d09d8df3 JB |
1301 | static void blkcg_exit(struct task_struct *tsk) |
1302 | { | |
1303 | if (tsk->throttle_queue) | |
1304 | blk_put_queue(tsk->throttle_queue); | |
1305 | tsk->throttle_queue = NULL; | |
1306 | } | |
1307 | ||
c165b3e3 | 1308 | struct cgroup_subsys io_cgrp_subsys = { |
92fb9748 | 1309 | .css_alloc = blkcg_css_alloc, |
4308a434 | 1310 | .css_online = blkcg_css_online, |
92fb9748 TH |
1311 | .css_offline = blkcg_css_offline, |
1312 | .css_free = blkcg_css_free, | |
f7331648 | 1313 | .css_rstat_flush = blkcg_rstat_flush, |
69d7fde5 | 1314 | .bind = blkcg_bind, |
2ee867dc | 1315 | .dfl_cftypes = blkcg_files, |
880f50e2 | 1316 | .legacy_cftypes = blkcg_legacy_files, |
c165b3e3 | 1317 | .legacy_name = "blkio", |
d09d8df3 | 1318 | .exit = blkcg_exit, |
1ced953b TH |
1319 | #ifdef CONFIG_MEMCG |
1320 | /* | |
1321 | * This ensures that, if available, memcg is automatically enabled | |
1322 | * together on the default hierarchy so that the owner cgroup can | |
1323 | * be retrieved from writeback pages. | |
1324 | */ | |
1325 | .depends_on = 1 << memory_cgrp_id, | |
1326 | #endif | |
676f7c8f | 1327 | }; |
c165b3e3 | 1328 | EXPORT_SYMBOL_GPL(io_cgrp_subsys); |
676f7c8f | 1329 | |
a2b1693b TH |
1330 | /** |
1331 | * blkcg_activate_policy - activate a blkcg policy on a request_queue | |
1332 | * @q: request_queue of interest | |
1333 | * @pol: blkcg policy to activate | |
1334 | * | |
1335 | * Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through | |
1336 | * bypass mode to populate its blkgs with policy_data for @pol. | |
1337 | * | |
1338 | * Activation happens with @q bypassed, so nobody would be accessing blkgs | |
1339 | * from IO path. Update of each blkg is protected by both queue and blkcg | |
1340 | * locks so that holding either lock and testing blkcg_policy_enabled() is | |
1341 | * always enough for dereferencing policy data. | |
1342 | * | |
1343 | * The caller is responsible for synchronizing [de]activations and policy | |
1344 | * [un]registerations. Returns 0 on success, -errno on failure. | |
1345 | */ | |
1346 | int blkcg_activate_policy(struct request_queue *q, | |
3c798398 | 1347 | const struct blkcg_policy *pol) |
a2b1693b | 1348 | { |
4c55f4f9 | 1349 | struct blkg_policy_data *pd_prealloc = NULL; |
9d179b86 | 1350 | struct blkcg_gq *blkg, *pinned_blkg = NULL; |
4c55f4f9 | 1351 | int ret; |
a2b1693b TH |
1352 | |
1353 | if (blkcg_policy_enabled(q, pol)) | |
1354 | return 0; | |
1355 | ||
344e9ffc | 1356 | if (queue_is_mq(q)) |
bd166ef1 | 1357 | blk_mq_freeze_queue(q); |
9d179b86 | 1358 | retry: |
0d945c1f | 1359 | spin_lock_irq(&q->queue_lock); |
a2b1693b | 1360 | |
9d179b86 | 1361 | /* blkg_list is pushed at the head, reverse walk to allocate parents first */ |
71c81407 | 1362 | list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) { |
4c55f4f9 TH |
1363 | struct blkg_policy_data *pd; |
1364 | ||
1365 | if (blkg->pd[pol->plid]) | |
1366 | continue; | |
a2b1693b | 1367 | |
9d179b86 TH |
1368 | /* If prealloc matches, use it; otherwise try GFP_NOWAIT */ |
1369 | if (blkg == pinned_blkg) { | |
1370 | pd = pd_prealloc; | |
1371 | pd_prealloc = NULL; | |
1372 | } else { | |
1373 | pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q, | |
1374 | blkg->blkcg); | |
1375 | } | |
1376 | ||
4c55f4f9 | 1377 | if (!pd) { |
9d179b86 TH |
1378 | /* |
1379 | * GFP_NOWAIT failed. Free the existing one and | |
1380 | * prealloc for @blkg w/ GFP_KERNEL. | |
1381 | */ | |
1382 | if (pinned_blkg) | |
1383 | blkg_put(pinned_blkg); | |
1384 | blkg_get(blkg); | |
1385 | pinned_blkg = blkg; | |
1386 | ||
0d945c1f | 1387 | spin_unlock_irq(&q->queue_lock); |
9d179b86 TH |
1388 | |
1389 | if (pd_prealloc) | |
1390 | pol->pd_free_fn(pd_prealloc); | |
1391 | pd_prealloc = pol->pd_alloc_fn(GFP_KERNEL, q, | |
1392 | blkg->blkcg); | |
1393 | if (pd_prealloc) | |
1394 | goto retry; | |
1395 | else | |
1396 | goto enomem; | |
4c55f4f9 | 1397 | } |
a2b1693b TH |
1398 | |
1399 | blkg->pd[pol->plid] = pd; | |
1400 | pd->blkg = blkg; | |
b276a876 | 1401 | pd->plid = pol->plid; |
a2b1693b TH |
1402 | } |
1403 | ||
9d179b86 TH |
1404 | /* all allocated, init in the same order */ |
1405 | if (pol->pd_init_fn) | |
1406 | list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) | |
1407 | pol->pd_init_fn(blkg->pd[pol->plid]); | |
1408 | ||
a2b1693b TH |
1409 | __set_bit(pol->plid, q->blkcg_pols); |
1410 | ret = 0; | |
4c55f4f9 | 1411 | |
0d945c1f | 1412 | spin_unlock_irq(&q->queue_lock); |
9d179b86 | 1413 | out: |
344e9ffc | 1414 | if (queue_is_mq(q)) |
bd166ef1 | 1415 | blk_mq_unfreeze_queue(q); |
9d179b86 TH |
1416 | if (pinned_blkg) |
1417 | blkg_put(pinned_blkg); | |
001bea73 TH |
1418 | if (pd_prealloc) |
1419 | pol->pd_free_fn(pd_prealloc); | |
a2b1693b | 1420 | return ret; |
9d179b86 TH |
1421 | |
1422 | enomem: | |
1423 | /* alloc failed, nothing's initialized yet, free everything */ | |
1424 | spin_lock_irq(&q->queue_lock); | |
1425 | list_for_each_entry(blkg, &q->blkg_list, q_node) { | |
858560b2 LJ |
1426 | struct blkcg *blkcg = blkg->blkcg; |
1427 | ||
1428 | spin_lock(&blkcg->lock); | |
9d179b86 TH |
1429 | if (blkg->pd[pol->plid]) { |
1430 | pol->pd_free_fn(blkg->pd[pol->plid]); | |
1431 | blkg->pd[pol->plid] = NULL; | |
1432 | } | |
858560b2 | 1433 | spin_unlock(&blkcg->lock); |
9d179b86 TH |
1434 | } |
1435 | spin_unlock_irq(&q->queue_lock); | |
1436 | ret = -ENOMEM; | |
1437 | goto out; | |
a2b1693b TH |
1438 | } |
1439 | EXPORT_SYMBOL_GPL(blkcg_activate_policy); | |
1440 | ||
1441 | /** | |
1442 | * blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue | |
1443 | * @q: request_queue of interest | |
1444 | * @pol: blkcg policy to deactivate | |
1445 | * | |
1446 | * Deactivate @pol on @q. Follows the same synchronization rules as | |
1447 | * blkcg_activate_policy(). | |
1448 | */ | |
1449 | void blkcg_deactivate_policy(struct request_queue *q, | |
3c798398 | 1450 | const struct blkcg_policy *pol) |
a2b1693b | 1451 | { |
3c798398 | 1452 | struct blkcg_gq *blkg; |
a2b1693b TH |
1453 | |
1454 | if (!blkcg_policy_enabled(q, pol)) | |
1455 | return; | |
1456 | ||
344e9ffc | 1457 | if (queue_is_mq(q)) |
bd166ef1 | 1458 | blk_mq_freeze_queue(q); |
bd166ef1 | 1459 | |
0d945c1f | 1460 | spin_lock_irq(&q->queue_lock); |
a2b1693b TH |
1461 | |
1462 | __clear_bit(pol->plid, q->blkcg_pols); | |
1463 | ||
1464 | list_for_each_entry(blkg, &q->blkg_list, q_node) { | |
858560b2 LJ |
1465 | struct blkcg *blkcg = blkg->blkcg; |
1466 | ||
1467 | spin_lock(&blkcg->lock); | |
001bea73 | 1468 | if (blkg->pd[pol->plid]) { |
6b065462 | 1469 | if (pol->pd_offline_fn) |
a9520cd6 | 1470 | pol->pd_offline_fn(blkg->pd[pol->plid]); |
001bea73 TH |
1471 | pol->pd_free_fn(blkg->pd[pol->plid]); |
1472 | blkg->pd[pol->plid] = NULL; | |
1473 | } | |
858560b2 | 1474 | spin_unlock(&blkcg->lock); |
a2b1693b TH |
1475 | } |
1476 | ||
0d945c1f | 1477 | spin_unlock_irq(&q->queue_lock); |
bd166ef1 | 1478 | |
344e9ffc | 1479 | if (queue_is_mq(q)) |
bd166ef1 | 1480 | blk_mq_unfreeze_queue(q); |
a2b1693b TH |
1481 | } |
1482 | EXPORT_SYMBOL_GPL(blkcg_deactivate_policy); | |
1483 | ||
e55cf798 JY |
1484 | static void blkcg_free_all_cpd(struct blkcg_policy *pol) |
1485 | { | |
1486 | struct blkcg *blkcg; | |
1487 | ||
1488 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { | |
1489 | if (blkcg->cpd[pol->plid]) { | |
1490 | pol->cpd_free_fn(blkcg->cpd[pol->plid]); | |
1491 | blkcg->cpd[pol->plid] = NULL; | |
1492 | } | |
1493 | } | |
1494 | } | |
1495 | ||
8bd435b3 | 1496 | /** |
3c798398 TH |
1497 | * blkcg_policy_register - register a blkcg policy |
1498 | * @pol: blkcg policy to register | |
8bd435b3 | 1499 | * |
3c798398 TH |
1500 | * Register @pol with blkcg core. Might sleep and @pol may be modified on |
1501 | * successful registration. Returns 0 on success and -errno on failure. | |
8bd435b3 | 1502 | */ |
d5bf0291 | 1503 | int blkcg_policy_register(struct blkcg_policy *pol) |
3e252066 | 1504 | { |
06b285bd | 1505 | struct blkcg *blkcg; |
8bd435b3 | 1506 | int i, ret; |
e8989fae | 1507 | |
838f13bf | 1508 | mutex_lock(&blkcg_pol_register_mutex); |
bc0d6501 TH |
1509 | mutex_lock(&blkcg_pol_mutex); |
1510 | ||
8bd435b3 TH |
1511 | /* find an empty slot */ |
1512 | ret = -ENOSPC; | |
1513 | for (i = 0; i < BLKCG_MAX_POLS; i++) | |
3c798398 | 1514 | if (!blkcg_policy[i]) |
8bd435b3 | 1515 | break; |
01c5f85a JA |
1516 | if (i >= BLKCG_MAX_POLS) { |
1517 | pr_warn("blkcg_policy_register: BLKCG_MAX_POLS too small\n"); | |
838f13bf | 1518 | goto err_unlock; |
01c5f85a | 1519 | } |
035d10b2 | 1520 | |
e8401073 | 1521 | /* Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs */ |
1522 | if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) || | |
1523 | (!pol->pd_alloc_fn ^ !pol->pd_free_fn)) | |
1524 | goto err_unlock; | |
1525 | ||
06b285bd | 1526 | /* register @pol */ |
3c798398 | 1527 | pol->plid = i; |
06b285bd TH |
1528 | blkcg_policy[pol->plid] = pol; |
1529 | ||
1530 | /* allocate and install cpd's */ | |
e4a9bde9 | 1531 | if (pol->cpd_alloc_fn) { |
06b285bd TH |
1532 | list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) { |
1533 | struct blkcg_policy_data *cpd; | |
1534 | ||
e4a9bde9 | 1535 | cpd = pol->cpd_alloc_fn(GFP_KERNEL); |
bbb427e3 | 1536 | if (!cpd) |
06b285bd | 1537 | goto err_free_cpds; |
06b285bd | 1538 | |
81437648 TH |
1539 | blkcg->cpd[pol->plid] = cpd; |
1540 | cpd->blkcg = blkcg; | |
06b285bd | 1541 | cpd->plid = pol->plid; |
86a5bba5 TH |
1542 | if (pol->cpd_init_fn) |
1543 | pol->cpd_init_fn(cpd); | |
06b285bd TH |
1544 | } |
1545 | } | |
1546 | ||
838f13bf | 1547 | mutex_unlock(&blkcg_pol_mutex); |
8bd435b3 | 1548 | |
8bd435b3 | 1549 | /* everything is in place, add intf files for the new policy */ |
2ee867dc TH |
1550 | if (pol->dfl_cftypes) |
1551 | WARN_ON(cgroup_add_dfl_cftypes(&io_cgrp_subsys, | |
1552 | pol->dfl_cftypes)); | |
880f50e2 | 1553 | if (pol->legacy_cftypes) |
c165b3e3 | 1554 | WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys, |
880f50e2 | 1555 | pol->legacy_cftypes)); |
838f13bf TH |
1556 | mutex_unlock(&blkcg_pol_register_mutex); |
1557 | return 0; | |
1558 | ||
06b285bd | 1559 | err_free_cpds: |
e55cf798 JY |
1560 | if (pol->cpd_free_fn) |
1561 | blkcg_free_all_cpd(pol); | |
1562 | ||
06b285bd | 1563 | blkcg_policy[pol->plid] = NULL; |
838f13bf | 1564 | err_unlock: |
bc0d6501 | 1565 | mutex_unlock(&blkcg_pol_mutex); |
838f13bf | 1566 | mutex_unlock(&blkcg_pol_register_mutex); |
8bd435b3 | 1567 | return ret; |
3e252066 | 1568 | } |
3c798398 | 1569 | EXPORT_SYMBOL_GPL(blkcg_policy_register); |
3e252066 | 1570 | |
8bd435b3 | 1571 | /** |
3c798398 TH |
1572 | * blkcg_policy_unregister - unregister a blkcg policy |
1573 | * @pol: blkcg policy to unregister | |
8bd435b3 | 1574 | * |
3c798398 | 1575 | * Undo blkcg_policy_register(@pol). Might sleep. |
8bd435b3 | 1576 | */ |
3c798398 | 1577 | void blkcg_policy_unregister(struct blkcg_policy *pol) |
3e252066 | 1578 | { |
838f13bf | 1579 | mutex_lock(&blkcg_pol_register_mutex); |
bc0d6501 | 1580 | |
3c798398 | 1581 | if (WARN_ON(blkcg_policy[pol->plid] != pol)) |
8bd435b3 TH |
1582 | goto out_unlock; |
1583 | ||
1584 | /* kill the intf files first */ | |
2ee867dc TH |
1585 | if (pol->dfl_cftypes) |
1586 | cgroup_rm_cftypes(pol->dfl_cftypes); | |
880f50e2 TH |
1587 | if (pol->legacy_cftypes) |
1588 | cgroup_rm_cftypes(pol->legacy_cftypes); | |
44ea53de | 1589 | |
06b285bd | 1590 | /* remove cpds and unregister */ |
838f13bf | 1591 | mutex_lock(&blkcg_pol_mutex); |
06b285bd | 1592 | |
e55cf798 JY |
1593 | if (pol->cpd_free_fn) |
1594 | blkcg_free_all_cpd(pol); | |
1595 | ||
3c798398 | 1596 | blkcg_policy[pol->plid] = NULL; |
06b285bd | 1597 | |
bc0d6501 | 1598 | mutex_unlock(&blkcg_pol_mutex); |
838f13bf TH |
1599 | out_unlock: |
1600 | mutex_unlock(&blkcg_pol_register_mutex); | |
3e252066 | 1601 | } |
3c798398 | 1602 | EXPORT_SYMBOL_GPL(blkcg_policy_unregister); |
903d23f0 | 1603 | |
d3f77dfd TH |
1604 | bool __blkcg_punt_bio_submit(struct bio *bio) |
1605 | { | |
1606 | struct blkcg_gq *blkg = bio->bi_blkg; | |
1607 | ||
1608 | /* consume the flag first */ | |
1609 | bio->bi_opf &= ~REQ_CGROUP_PUNT; | |
1610 | ||
1611 | /* never bounce for the root cgroup */ | |
1612 | if (!blkg->parent) | |
1613 | return false; | |
1614 | ||
1615 | spin_lock_bh(&blkg->async_bio_lock); | |
1616 | bio_list_add(&blkg->async_bios, bio); | |
1617 | spin_unlock_bh(&blkg->async_bio_lock); | |
1618 | ||
1619 | queue_work(blkcg_punt_bio_wq, &blkg->async_bio_work); | |
1620 | return true; | |
1621 | } | |
1622 | ||
d09d8df3 JB |
1623 | /* |
1624 | * Scale the accumulated delay based on how long it has been since we updated | |
1625 | * the delay. We only call this when we are adding delay, in case it's been a | |
1626 | * while since we added delay, and when we are checking to see if we need to | |
1627 | * delay a task, to account for any delays that may have occurred. | |
1628 | */ | |
1629 | static void blkcg_scale_delay(struct blkcg_gq *blkg, u64 now) | |
1630 | { | |
1631 | u64 old = atomic64_read(&blkg->delay_start); | |
1632 | ||
54c52e10 TH |
1633 | /* negative use_delay means no scaling, see blkcg_set_delay() */ |
1634 | if (atomic_read(&blkg->use_delay) < 0) | |
1635 | return; | |
1636 | ||
d09d8df3 JB |
1637 | /* |
1638 | * We only want to scale down every second. The idea here is that we | |
1639 | * want to delay people for min(delay_nsec, NSEC_PER_SEC) in a certain | |
1640 | * time window. We only want to throttle tasks for recent delay that | |
1641 | * has occurred, in 1 second time windows since that's the maximum | |
1642 | * things can be throttled. We save the current delay window in | |
1643 | * blkg->last_delay so we know what amount is still left to be charged | |
1644 | * to the blkg from this point onward. blkg->last_use keeps track of | |
1645 | * the use_delay counter. The idea is if we're unthrottling the blkg we | |
1646 | * are ok with whatever is happening now, and we can take away more of | |
1647 | * the accumulated delay as we've already throttled enough that | |
1648 | * everybody is happy with their IO latencies. | |
1649 | */ | |
1650 | if (time_before64(old + NSEC_PER_SEC, now) && | |
96388f57 | 1651 | atomic64_try_cmpxchg(&blkg->delay_start, &old, now)) { |
d09d8df3 JB |
1652 | u64 cur = atomic64_read(&blkg->delay_nsec); |
1653 | u64 sub = min_t(u64, blkg->last_delay, now - old); | |
1654 | int cur_use = atomic_read(&blkg->use_delay); | |
1655 | ||
1656 | /* | |
1657 | * We've been unthrottled, subtract a larger chunk of our | |
1658 | * accumulated delay. | |
1659 | */ | |
1660 | if (cur_use < blkg->last_use) | |
1661 | sub = max_t(u64, sub, blkg->last_delay >> 1); | |
1662 | ||
1663 | /* | |
1664 | * This shouldn't happen, but handle it anyway. Our delay_nsec | |
1665 | * should only ever be growing except here where we subtract out | |
1666 | * min(last_delay, 1 second), but lord knows bugs happen and I'd | |
1667 | * rather not end up with negative numbers. | |
1668 | */ | |
1669 | if (unlikely(cur < sub)) { | |
1670 | atomic64_set(&blkg->delay_nsec, 0); | |
1671 | blkg->last_delay = 0; | |
1672 | } else { | |
1673 | atomic64_sub(sub, &blkg->delay_nsec); | |
1674 | blkg->last_delay = cur - sub; | |
1675 | } | |
1676 | blkg->last_use = cur_use; | |
1677 | } | |
1678 | } | |
1679 | ||
1680 | /* | |
1681 | * This is called when we want to actually walk up the hierarchy and check to | |
1682 | * see if we need to throttle, and then actually throttle if there is some | |
1683 | * accumulated delay. This should only be called upon return to user space so | |
1684 | * we're not holding some lock that would induce a priority inversion. | |
1685 | */ | |
1686 | static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay) | |
1687 | { | |
fd112c74 | 1688 | unsigned long pflags; |
5160a5a5 | 1689 | bool clamp; |
d09d8df3 JB |
1690 | u64 now = ktime_to_ns(ktime_get()); |
1691 | u64 exp; | |
1692 | u64 delay_nsec = 0; | |
1693 | int tok; | |
1694 | ||
1695 | while (blkg->parent) { | |
5160a5a5 TH |
1696 | int use_delay = atomic_read(&blkg->use_delay); |
1697 | ||
1698 | if (use_delay) { | |
1699 | u64 this_delay; | |
1700 | ||
d09d8df3 | 1701 | blkcg_scale_delay(blkg, now); |
5160a5a5 TH |
1702 | this_delay = atomic64_read(&blkg->delay_nsec); |
1703 | if (this_delay > delay_nsec) { | |
1704 | delay_nsec = this_delay; | |
1705 | clamp = use_delay > 0; | |
1706 | } | |
d09d8df3 JB |
1707 | } |
1708 | blkg = blkg->parent; | |
1709 | } | |
1710 | ||
1711 | if (!delay_nsec) | |
1712 | return; | |
1713 | ||
1714 | /* | |
1715 | * Let's not sleep for all eternity if we've amassed a huge delay. | |
1716 | * Swapping or metadata IO can accumulate 10's of seconds worth of | |
1717 | * delay, and we want userspace to be able to do _something_ so cap the | |
5160a5a5 TH |
1718 | * delays at 0.25s. If there's 10's of seconds worth of delay then the |
1719 | * tasks will be delayed for 0.25 second for every syscall. If | |
1720 | * blkcg_set_delay() was used as indicated by negative use_delay, the | |
1721 | * caller is responsible for regulating the range. | |
d09d8df3 | 1722 | */ |
5160a5a5 TH |
1723 | if (clamp) |
1724 | delay_nsec = min_t(u64, delay_nsec, 250 * NSEC_PER_MSEC); | |
d09d8df3 | 1725 | |
fd112c74 JB |
1726 | if (use_memdelay) |
1727 | psi_memstall_enter(&pflags); | |
d09d8df3 JB |
1728 | |
1729 | exp = ktime_add_ns(now, delay_nsec); | |
1730 | tok = io_schedule_prepare(); | |
1731 | do { | |
1732 | __set_current_state(TASK_KILLABLE); | |
1733 | if (!schedule_hrtimeout(&exp, HRTIMER_MODE_ABS)) | |
1734 | break; | |
1735 | } while (!fatal_signal_pending(current)); | |
1736 | io_schedule_finish(tok); | |
fd112c74 JB |
1737 | |
1738 | if (use_memdelay) | |
1739 | psi_memstall_leave(&pflags); | |
d09d8df3 JB |
1740 | } |
1741 | ||
1742 | /** | |
1743 | * blkcg_maybe_throttle_current - throttle the current task if it has been marked | |
1744 | * | |
1745 | * This is only called if we've been marked with set_notify_resume(). Obviously | |
1746 | * we can be set_notify_resume() for reasons other than blkcg throttling, so we | |
1747 | * check to see if current->throttle_queue is set and if not this doesn't do | |
1748 | * anything. This should only ever be called by the resume code, it's not meant | |
1749 | * to be called by people willy-nilly as it will actually do the work to | |
1750 | * throttle the task if it is setup for throttling. | |
1751 | */ | |
1752 | void blkcg_maybe_throttle_current(void) | |
1753 | { | |
1754 | struct request_queue *q = current->throttle_queue; | |
d09d8df3 JB |
1755 | struct blkcg *blkcg; |
1756 | struct blkcg_gq *blkg; | |
1757 | bool use_memdelay = current->use_memdelay; | |
1758 | ||
1759 | if (!q) | |
1760 | return; | |
1761 | ||
1762 | current->throttle_queue = NULL; | |
1763 | current->use_memdelay = false; | |
1764 | ||
1765 | rcu_read_lock(); | |
82778259 | 1766 | blkcg = css_to_blkcg(blkcg_css()); |
d09d8df3 JB |
1767 | if (!blkcg) |
1768 | goto out; | |
1769 | blkg = blkg_lookup(blkcg, q); | |
1770 | if (!blkg) | |
1771 | goto out; | |
7754f669 | 1772 | if (!blkg_tryget(blkg)) |
d09d8df3 JB |
1773 | goto out; |
1774 | rcu_read_unlock(); | |
d09d8df3 JB |
1775 | |
1776 | blkcg_maybe_throttle_blkg(blkg, use_memdelay); | |
1777 | blkg_put(blkg); | |
cc7ecc25 | 1778 | blk_put_queue(q); |
d09d8df3 JB |
1779 | return; |
1780 | out: | |
1781 | rcu_read_unlock(); | |
1782 | blk_put_queue(q); | |
1783 | } | |
d09d8df3 JB |
1784 | |
1785 | /** | |
1786 | * blkcg_schedule_throttle - this task needs to check for throttling | |
de185b56 | 1787 | * @gendisk: disk to throttle |
537d71b3 | 1788 | * @use_memdelay: do we charge this to memory delay for PSI |
d09d8df3 JB |
1789 | * |
1790 | * This is called by the IO controller when we know there's delay accumulated | |
1791 | * for the blkg for this task. We do not pass the blkg because there are places | |
1792 | * we call this that may not have that information, the swapping code for | |
de185b56 | 1793 | * instance will only have a block_device at that point. This set's the |
d09d8df3 JB |
1794 | * notify_resume for the task to check and see if it requires throttling before |
1795 | * returning to user space. | |
1796 | * | |
1797 | * We will only schedule once per syscall. You can call this over and over | |
1798 | * again and it will only do the check once upon return to user space, and only | |
1799 | * throttle once. If the task needs to be throttled again it'll need to be | |
1800 | * re-set at the next time we see the task. | |
1801 | */ | |
de185b56 | 1802 | void blkcg_schedule_throttle(struct gendisk *disk, bool use_memdelay) |
d09d8df3 | 1803 | { |
de185b56 CH |
1804 | struct request_queue *q = disk->queue; |
1805 | ||
d09d8df3 JB |
1806 | if (unlikely(current->flags & PF_KTHREAD)) |
1807 | return; | |
1808 | ||
49d1822b CX |
1809 | if (current->throttle_queue != q) { |
1810 | if (!blk_get_queue(q)) | |
1811 | return; | |
1812 | ||
1813 | if (current->throttle_queue) | |
1814 | blk_put_queue(current->throttle_queue); | |
1815 | current->throttle_queue = q; | |
1816 | } | |
d09d8df3 | 1817 | |
d09d8df3 JB |
1818 | if (use_memdelay) |
1819 | current->use_memdelay = use_memdelay; | |
1820 | set_notify_resume(current); | |
1821 | } | |
d09d8df3 JB |
1822 | |
1823 | /** | |
1824 | * blkcg_add_delay - add delay to this blkg | |
537d71b3 BVA |
1825 | * @blkg: blkg of interest |
1826 | * @now: the current time in nanoseconds | |
1827 | * @delta: how many nanoseconds of delay to add | |
d09d8df3 JB |
1828 | * |
1829 | * Charge @delta to the blkg's current delay accumulation. This is used to | |
1830 | * throttle tasks if an IO controller thinks we need more throttling. | |
1831 | */ | |
1832 | void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta) | |
1833 | { | |
54c52e10 TH |
1834 | if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0)) |
1835 | return; | |
d09d8df3 JB |
1836 | blkcg_scale_delay(blkg, now); |
1837 | atomic64_add(delta, &blkg->delay_nsec); | |
1838 | } | |
d09d8df3 | 1839 | |
28fc591f CH |
1840 | /** |
1841 | * blkg_tryget_closest - try and get a blkg ref on the closet blkg | |
13c7863d CH |
1842 | * @bio: target bio |
1843 | * @css: target css | |
28fc591f | 1844 | * |
13c7863d CH |
1845 | * As the failure mode here is to walk up the blkg tree, this ensure that the |
1846 | * blkg->parent pointers are always valid. This returns the blkg that it ended | |
1847 | * up taking a reference on or %NULL if no reference was taken. | |
28fc591f | 1848 | */ |
13c7863d CH |
1849 | static inline struct blkcg_gq *blkg_tryget_closest(struct bio *bio, |
1850 | struct cgroup_subsys_state *css) | |
28fc591f | 1851 | { |
13c7863d | 1852 | struct blkcg_gq *blkg, *ret_blkg = NULL; |
28fc591f | 1853 | |
13c7863d | 1854 | rcu_read_lock(); |
99e60387 | 1855 | blkg = blkg_lookup_create(css_to_blkcg(css), bio->bi_bdev->bd_disk); |
28fc591f CH |
1856 | while (blkg) { |
1857 | if (blkg_tryget(blkg)) { | |
1858 | ret_blkg = blkg; | |
1859 | break; | |
1860 | } | |
1861 | blkg = blkg->parent; | |
1862 | } | |
13c7863d | 1863 | rcu_read_unlock(); |
28fc591f CH |
1864 | |
1865 | return ret_blkg; | |
1866 | } | |
1867 | ||
1868 | /** | |
1869 | * bio_associate_blkg_from_css - associate a bio with a specified css | |
1870 | * @bio: target bio | |
1871 | * @css: target css | |
1872 | * | |
1873 | * Associate @bio with the blkg found by combining the css's blkg and the | |
1874 | * request_queue of the @bio. An association failure is handled by walking up | |
1875 | * the blkg tree. Therefore, the blkg associated can be anything between @blkg | |
1876 | * and q->root_blkg. This situation only happens when a cgroup is dying and | |
1877 | * then the remaining bios will spill to the closest alive blkg. | |
1878 | * | |
1879 | * A reference will be taken on the blkg and will be released when @bio is | |
1880 | * freed. | |
1881 | */ | |
1882 | void bio_associate_blkg_from_css(struct bio *bio, | |
1883 | struct cgroup_subsys_state *css) | |
1884 | { | |
28fc591f CH |
1885 | if (bio->bi_blkg) |
1886 | blkg_put(bio->bi_blkg); | |
1887 | ||
a5b97526 | 1888 | if (css && css->parent) { |
13c7863d | 1889 | bio->bi_blkg = blkg_tryget_closest(bio, css); |
a5b97526 | 1890 | } else { |
ed6cddef PB |
1891 | blkg_get(bdev_get_queue(bio->bi_bdev)->root_blkg); |
1892 | bio->bi_blkg = bdev_get_queue(bio->bi_bdev)->root_blkg; | |
a5b97526 | 1893 | } |
28fc591f CH |
1894 | } |
1895 | EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css); | |
1896 | ||
1897 | /** | |
1898 | * bio_associate_blkg - associate a bio with a blkg | |
1899 | * @bio: target bio | |
1900 | * | |
1901 | * Associate @bio with the blkg found from the bio's css and request_queue. | |
1902 | * If one is not found, bio_lookup_blkg() creates the blkg. If a blkg is | |
1903 | * already associated, the css is reused and association redone as the | |
1904 | * request_queue may have changed. | |
1905 | */ | |
1906 | void bio_associate_blkg(struct bio *bio) | |
1907 | { | |
1908 | struct cgroup_subsys_state *css; | |
1909 | ||
1910 | rcu_read_lock(); | |
1911 | ||
1912 | if (bio->bi_blkg) | |
bbb1ebe7 | 1913 | css = bio_blkcg_css(bio); |
28fc591f CH |
1914 | else |
1915 | css = blkcg_css(); | |
1916 | ||
1917 | bio_associate_blkg_from_css(bio, css); | |
1918 | ||
1919 | rcu_read_unlock(); | |
1920 | } | |
1921 | EXPORT_SYMBOL_GPL(bio_associate_blkg); | |
1922 | ||
1923 | /** | |
1924 | * bio_clone_blkg_association - clone blkg association from src to dst bio | |
1925 | * @dst: destination bio | |
1926 | * @src: source bio | |
1927 | */ | |
1928 | void bio_clone_blkg_association(struct bio *dst, struct bio *src) | |
1929 | { | |
22b106e5 JK |
1930 | if (src->bi_blkg) |
1931 | bio_associate_blkg_from_css(dst, bio_blkcg_css(src)); | |
28fc591f CH |
1932 | } |
1933 | EXPORT_SYMBOL_GPL(bio_clone_blkg_association); | |
1934 | ||
db18a53e CH |
1935 | static int blk_cgroup_io_type(struct bio *bio) |
1936 | { | |
1937 | if (op_is_discard(bio->bi_opf)) | |
1938 | return BLKG_IOSTAT_DISCARD; | |
1939 | if (op_is_write(bio->bi_opf)) | |
1940 | return BLKG_IOSTAT_WRITE; | |
1941 | return BLKG_IOSTAT_READ; | |
1942 | } | |
1943 | ||
1944 | void blk_cgroup_bio_start(struct bio *bio) | |
1945 | { | |
1946 | int rwd = blk_cgroup_io_type(bio), cpu; | |
1947 | struct blkg_iostat_set *bis; | |
3c08b093 | 1948 | unsigned long flags; |
db18a53e CH |
1949 | |
1950 | cpu = get_cpu(); | |
1951 | bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu); | |
3c08b093 | 1952 | flags = u64_stats_update_begin_irqsave(&bis->sync); |
db18a53e CH |
1953 | |
1954 | /* | |
1955 | * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split | |
1956 | * bio and we would have already accounted for the size of the bio. | |
1957 | */ | |
1958 | if (!bio_flagged(bio, BIO_CGROUP_ACCT)) { | |
1959 | bio_set_flag(bio, BIO_CGROUP_ACCT); | |
0b8cc25d | 1960 | bis->cur.bytes[rwd] += bio->bi_iter.bi_size; |
db18a53e CH |
1961 | } |
1962 | bis->cur.ios[rwd]++; | |
1963 | ||
3c08b093 | 1964 | u64_stats_update_end_irqrestore(&bis->sync, flags); |
db18a53e CH |
1965 | if (cgroup_subsys_on_dfl(io_cgrp_subsys)) |
1966 | cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu); | |
1967 | put_cpu(); | |
1968 | } | |
1969 | ||
216889aa CH |
1970 | bool blk_cgroup_congested(void) |
1971 | { | |
1972 | struct cgroup_subsys_state *css; | |
1973 | bool ret = false; | |
1974 | ||
1975 | rcu_read_lock(); | |
d200ca14 | 1976 | for (css = blkcg_css(); css; css = css->parent) { |
216889aa CH |
1977 | if (atomic_read(&css->cgroup->congestion_count)) { |
1978 | ret = true; | |
1979 | break; | |
1980 | } | |
216889aa CH |
1981 | } |
1982 | rcu_read_unlock(); | |
1983 | return ret; | |
1984 | } | |
1985 | ||
d3f77dfd TH |
1986 | static int __init blkcg_init(void) |
1987 | { | |
1988 | blkcg_punt_bio_wq = alloc_workqueue("blkcg_punt_bio", | |
1989 | WQ_MEM_RECLAIM | WQ_FREEZABLE | | |
1990 | WQ_UNBOUND | WQ_SYSFS, 0); | |
1991 | if (!blkcg_punt_bio_wq) | |
1992 | return -ENOMEM; | |
1993 | return 0; | |
1994 | } | |
1995 | subsys_initcall(blkcg_init); | |
1996 | ||
903d23f0 JB |
1997 | module_param(blkcg_debug_stats, bool, 0644); |
1998 | MODULE_PARM_DESC(blkcg_debug_stats, "True if you want debug stats, false if not"); |