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31e4c28d VG |
1 | #ifndef _BLK_CGROUP_H |
2 | #define _BLK_CGROUP_H | |
3 | /* | |
4 | * Common Block IO controller cgroup interface | |
5 | * | |
6 | * Based on ideas and code from CFQ, CFS and BFQ: | |
7 | * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> | |
8 | * | |
9 | * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it> | |
10 | * Paolo Valente <paolo.valente@unimore.it> | |
11 | * | |
12 | * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com> | |
13 | * Nauman Rafique <nauman@google.com> | |
14 | */ | |
15 | ||
16 | #include <linux/cgroup.h> | |
575969a0 | 17 | #include <linux/u64_stats_sync.h> |
829fdb50 | 18 | #include <linux/seq_file.h> |
31e4c28d | 19 | |
9355aede VG |
20 | /* Max limits for throttle policy */ |
21 | #define THROTL_IOPS_MAX UINT_MAX | |
22 | ||
3381cb8d TH |
23 | /* CFQ specific, out here for blkcg->cfq_weight */ |
24 | #define CFQ_WEIGHT_MIN 10 | |
25 | #define CFQ_WEIGHT_MAX 1000 | |
26 | #define CFQ_WEIGHT_DEFAULT 500 | |
27 | ||
f48ec1d7 TH |
28 | #ifdef CONFIG_BLK_CGROUP |
29 | ||
edcb0722 TH |
30 | enum blkg_rwstat_type { |
31 | BLKG_RWSTAT_READ, | |
32 | BLKG_RWSTAT_WRITE, | |
33 | BLKG_RWSTAT_SYNC, | |
34 | BLKG_RWSTAT_ASYNC, | |
35 | ||
36 | BLKG_RWSTAT_NR, | |
37 | BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR, | |
303a3acb DS |
38 | }; |
39 | ||
3c798398 | 40 | struct blkcg { |
36558c8a TH |
41 | struct cgroup_subsys_state css; |
42 | spinlock_t lock; | |
43 | struct hlist_head blkg_list; | |
9a9e8a26 TH |
44 | |
45 | /* for policies to test whether associated blkcg has changed */ | |
36558c8a | 46 | uint64_t id; |
3381cb8d | 47 | |
3c798398 | 48 | /* TODO: per-policy storage in blkcg */ |
36558c8a | 49 | unsigned int cfq_weight; /* belongs to cfq */ |
31e4c28d VG |
50 | }; |
51 | ||
edcb0722 TH |
52 | struct blkg_stat { |
53 | struct u64_stats_sync syncp; | |
54 | uint64_t cnt; | |
55 | }; | |
56 | ||
57 | struct blkg_rwstat { | |
58 | struct u64_stats_sync syncp; | |
59 | uint64_t cnt[BLKG_RWSTAT_NR]; | |
60 | }; | |
61 | ||
f95a04af TH |
62 | /* |
63 | * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a | |
64 | * request_queue (q). This is used by blkcg policies which need to track | |
65 | * information per blkcg - q pair. | |
66 | * | |
67 | * There can be multiple active blkcg policies and each has its private | |
68 | * data on each blkg, the size of which is determined by | |
69 | * blkcg_policy->pd_size. blkcg core allocates and frees such areas | |
70 | * together with blkg and invokes pd_init/exit_fn() methods. | |
71 | * | |
72 | * Such private data must embed struct blkg_policy_data (pd) at the | |
73 | * beginning and pd_size can't be smaller than pd. | |
74 | */ | |
0381411e TH |
75 | struct blkg_policy_data { |
76 | /* the blkg this per-policy data belongs to */ | |
3c798398 | 77 | struct blkcg_gq *blkg; |
0381411e | 78 | |
a2b1693b | 79 | /* used during policy activation */ |
36558c8a | 80 | struct list_head alloc_node; |
0381411e TH |
81 | }; |
82 | ||
3c798398 TH |
83 | /* association between a blk cgroup and a request queue */ |
84 | struct blkcg_gq { | |
c875f4d0 | 85 | /* Pointer to the associated request_queue */ |
36558c8a TH |
86 | struct request_queue *q; |
87 | struct list_head q_node; | |
88 | struct hlist_node blkcg_node; | |
3c798398 | 89 | struct blkcg *blkcg; |
1adaf3dd | 90 | /* reference count */ |
36558c8a | 91 | int refcnt; |
22084190 | 92 | |
36558c8a | 93 | struct blkg_policy_data *pd[BLKCG_MAX_POLS]; |
1adaf3dd | 94 | |
36558c8a | 95 | struct rcu_head rcu_head; |
31e4c28d VG |
96 | }; |
97 | ||
3c798398 TH |
98 | typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg); |
99 | typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg); | |
100 | typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg); | |
3e252066 | 101 | |
3c798398 | 102 | struct blkcg_policy { |
36558c8a TH |
103 | int plid; |
104 | /* policy specific private data size */ | |
f95a04af | 105 | size_t pd_size; |
36558c8a TH |
106 | /* cgroup files for the policy */ |
107 | struct cftype *cftypes; | |
f9fcc2d3 TH |
108 | |
109 | /* operations */ | |
110 | blkcg_pol_init_pd_fn *pd_init_fn; | |
111 | blkcg_pol_exit_pd_fn *pd_exit_fn; | |
112 | blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; | |
3e252066 VG |
113 | }; |
114 | ||
3c798398 | 115 | extern struct blkcg blkcg_root; |
36558c8a | 116 | |
3c798398 TH |
117 | struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup); |
118 | struct blkcg *bio_blkcg(struct bio *bio); | |
119 | struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q); | |
120 | struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, | |
121 | struct request_queue *q); | |
36558c8a TH |
122 | int blkcg_init_queue(struct request_queue *q); |
123 | void blkcg_drain_queue(struct request_queue *q); | |
124 | void blkcg_exit_queue(struct request_queue *q); | |
5efd6113 | 125 | |
3e252066 | 126 | /* Blkio controller policy registration */ |
3c798398 TH |
127 | int blkcg_policy_register(struct blkcg_policy *pol); |
128 | void blkcg_policy_unregister(struct blkcg_policy *pol); | |
36558c8a | 129 | int blkcg_activate_policy(struct request_queue *q, |
3c798398 | 130 | const struct blkcg_policy *pol); |
36558c8a | 131 | void blkcg_deactivate_policy(struct request_queue *q, |
3c798398 | 132 | const struct blkcg_policy *pol); |
3e252066 | 133 | |
3c798398 | 134 | void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, |
f95a04af TH |
135 | u64 (*prfill)(struct seq_file *, |
136 | struct blkg_policy_data *, int), | |
3c798398 | 137 | const struct blkcg_policy *pol, int data, |
ec399347 | 138 | bool show_total); |
f95a04af TH |
139 | u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v); |
140 | u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, | |
829fdb50 | 141 | const struct blkg_rwstat *rwstat); |
f95a04af TH |
142 | u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off); |
143 | u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, | |
144 | int off); | |
829fdb50 TH |
145 | |
146 | struct blkg_conf_ctx { | |
36558c8a | 147 | struct gendisk *disk; |
3c798398 | 148 | struct blkcg_gq *blkg; |
36558c8a | 149 | u64 v; |
829fdb50 TH |
150 | }; |
151 | ||
3c798398 TH |
152 | int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, |
153 | const char *input, struct blkg_conf_ctx *ctx); | |
829fdb50 TH |
154 | void blkg_conf_finish(struct blkg_conf_ctx *ctx); |
155 | ||
156 | ||
0381411e TH |
157 | /** |
158 | * blkg_to_pdata - get policy private data | |
159 | * @blkg: blkg of interest | |
160 | * @pol: policy of interest | |
161 | * | |
162 | * Return pointer to private data associated with the @blkg-@pol pair. | |
163 | */ | |
f95a04af TH |
164 | static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, |
165 | struct blkcg_policy *pol) | |
0381411e | 166 | { |
f95a04af | 167 | return blkg ? blkg->pd[pol->plid] : NULL; |
0381411e TH |
168 | } |
169 | ||
170 | /** | |
171 | * pdata_to_blkg - get blkg associated with policy private data | |
f95a04af | 172 | * @pd: policy private data of interest |
0381411e | 173 | * |
f95a04af | 174 | * @pd is policy private data. Determine the blkg it's associated with. |
0381411e | 175 | */ |
f95a04af | 176 | static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) |
0381411e | 177 | { |
f95a04af | 178 | return pd ? pd->blkg : NULL; |
0381411e TH |
179 | } |
180 | ||
54e7ed12 TH |
181 | /** |
182 | * blkg_path - format cgroup path of blkg | |
183 | * @blkg: blkg of interest | |
184 | * @buf: target buffer | |
185 | * @buflen: target buffer length | |
186 | * | |
187 | * Format the path of the cgroup of @blkg into @buf. | |
188 | */ | |
3c798398 | 189 | static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) |
afc24d49 | 190 | { |
54e7ed12 TH |
191 | int ret; |
192 | ||
193 | rcu_read_lock(); | |
194 | ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); | |
195 | rcu_read_unlock(); | |
196 | if (ret) | |
197 | strncpy(buf, "<unavailable>", buflen); | |
198 | return ret; | |
afc24d49 VG |
199 | } |
200 | ||
1adaf3dd TH |
201 | /** |
202 | * blkg_get - get a blkg reference | |
203 | * @blkg: blkg to get | |
204 | * | |
205 | * The caller should be holding queue_lock and an existing reference. | |
206 | */ | |
3c798398 | 207 | static inline void blkg_get(struct blkcg_gq *blkg) |
1adaf3dd TH |
208 | { |
209 | lockdep_assert_held(blkg->q->queue_lock); | |
210 | WARN_ON_ONCE(!blkg->refcnt); | |
211 | blkg->refcnt++; | |
212 | } | |
213 | ||
3c798398 | 214 | void __blkg_release(struct blkcg_gq *blkg); |
1adaf3dd TH |
215 | |
216 | /** | |
217 | * blkg_put - put a blkg reference | |
218 | * @blkg: blkg to put | |
219 | * | |
220 | * The caller should be holding queue_lock. | |
221 | */ | |
3c798398 | 222 | static inline void blkg_put(struct blkcg_gq *blkg) |
1adaf3dd TH |
223 | { |
224 | lockdep_assert_held(blkg->q->queue_lock); | |
225 | WARN_ON_ONCE(blkg->refcnt <= 0); | |
226 | if (!--blkg->refcnt) | |
227 | __blkg_release(blkg); | |
228 | } | |
229 | ||
edcb0722 TH |
230 | /** |
231 | * blkg_stat_add - add a value to a blkg_stat | |
232 | * @stat: target blkg_stat | |
233 | * @val: value to add | |
234 | * | |
235 | * Add @val to @stat. The caller is responsible for synchronizing calls to | |
236 | * this function. | |
237 | */ | |
238 | static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val) | |
239 | { | |
240 | u64_stats_update_begin(&stat->syncp); | |
241 | stat->cnt += val; | |
242 | u64_stats_update_end(&stat->syncp); | |
243 | } | |
244 | ||
245 | /** | |
246 | * blkg_stat_read - read the current value of a blkg_stat | |
247 | * @stat: blkg_stat to read | |
248 | * | |
249 | * Read the current value of @stat. This function can be called without | |
250 | * synchroniztion and takes care of u64 atomicity. | |
251 | */ | |
252 | static inline uint64_t blkg_stat_read(struct blkg_stat *stat) | |
253 | { | |
254 | unsigned int start; | |
255 | uint64_t v; | |
256 | ||
257 | do { | |
258 | start = u64_stats_fetch_begin(&stat->syncp); | |
259 | v = stat->cnt; | |
260 | } while (u64_stats_fetch_retry(&stat->syncp, start)); | |
261 | ||
262 | return v; | |
263 | } | |
264 | ||
265 | /** | |
266 | * blkg_stat_reset - reset a blkg_stat | |
267 | * @stat: blkg_stat to reset | |
268 | */ | |
269 | static inline void blkg_stat_reset(struct blkg_stat *stat) | |
270 | { | |
271 | stat->cnt = 0; | |
272 | } | |
273 | ||
274 | /** | |
275 | * blkg_rwstat_add - add a value to a blkg_rwstat | |
276 | * @rwstat: target blkg_rwstat | |
277 | * @rw: mask of REQ_{WRITE|SYNC} | |
278 | * @val: value to add | |
279 | * | |
280 | * Add @val to @rwstat. The counters are chosen according to @rw. The | |
281 | * caller is responsible for synchronizing calls to this function. | |
282 | */ | |
283 | static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat, | |
284 | int rw, uint64_t val) | |
285 | { | |
286 | u64_stats_update_begin(&rwstat->syncp); | |
287 | ||
288 | if (rw & REQ_WRITE) | |
289 | rwstat->cnt[BLKG_RWSTAT_WRITE] += val; | |
290 | else | |
291 | rwstat->cnt[BLKG_RWSTAT_READ] += val; | |
292 | if (rw & REQ_SYNC) | |
293 | rwstat->cnt[BLKG_RWSTAT_SYNC] += val; | |
294 | else | |
295 | rwstat->cnt[BLKG_RWSTAT_ASYNC] += val; | |
296 | ||
297 | u64_stats_update_end(&rwstat->syncp); | |
298 | } | |
299 | ||
300 | /** | |
301 | * blkg_rwstat_read - read the current values of a blkg_rwstat | |
302 | * @rwstat: blkg_rwstat to read | |
303 | * | |
304 | * Read the current snapshot of @rwstat and return it as the return value. | |
305 | * This function can be called without synchronization and takes care of | |
306 | * u64 atomicity. | |
307 | */ | |
c94bed89 | 308 | static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat) |
edcb0722 TH |
309 | { |
310 | unsigned int start; | |
311 | struct blkg_rwstat tmp; | |
312 | ||
313 | do { | |
314 | start = u64_stats_fetch_begin(&rwstat->syncp); | |
315 | tmp = *rwstat; | |
316 | } while (u64_stats_fetch_retry(&rwstat->syncp, start)); | |
317 | ||
318 | return tmp; | |
319 | } | |
320 | ||
321 | /** | |
322 | * blkg_rwstat_sum - read the total count of a blkg_rwstat | |
323 | * @rwstat: blkg_rwstat to read | |
324 | * | |
325 | * Return the total count of @rwstat regardless of the IO direction. This | |
326 | * function can be called without synchronization and takes care of u64 | |
327 | * atomicity. | |
328 | */ | |
329 | static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat) | |
330 | { | |
331 | struct blkg_rwstat tmp = blkg_rwstat_read(rwstat); | |
332 | ||
333 | return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]; | |
334 | } | |
335 | ||
336 | /** | |
337 | * blkg_rwstat_reset - reset a blkg_rwstat | |
338 | * @rwstat: blkg_rwstat to reset | |
339 | */ | |
340 | static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat) | |
341 | { | |
342 | memset(rwstat->cnt, 0, sizeof(rwstat->cnt)); | |
343 | } | |
344 | ||
36558c8a TH |
345 | #else /* CONFIG_BLK_CGROUP */ |
346 | ||
347 | struct cgroup; | |
2f5ea477 | 348 | |
f95a04af TH |
349 | struct blkg_policy_data { |
350 | }; | |
351 | ||
3c798398 | 352 | struct blkcg_gq { |
2f5ea477 JA |
353 | }; |
354 | ||
3c798398 | 355 | struct blkcg_policy { |
3e252066 VG |
356 | }; |
357 | ||
3c798398 TH |
358 | static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; } |
359 | static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; } | |
360 | static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } | |
5efd6113 TH |
361 | static inline int blkcg_init_queue(struct request_queue *q) { return 0; } |
362 | static inline void blkcg_drain_queue(struct request_queue *q) { } | |
363 | static inline void blkcg_exit_queue(struct request_queue *q) { } | |
3c798398 TH |
364 | static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; } |
365 | static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { } | |
a2b1693b | 366 | static inline int blkcg_activate_policy(struct request_queue *q, |
3c798398 | 367 | const struct blkcg_policy *pol) { return 0; } |
a2b1693b | 368 | static inline void blkcg_deactivate_policy(struct request_queue *q, |
3c798398 TH |
369 | const struct blkcg_policy *pol) { } |
370 | ||
f95a04af TH |
371 | static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, |
372 | struct blkcg_policy *pol) { return NULL; } | |
373 | static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; } | |
3c798398 TH |
374 | static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; } |
375 | static inline void blkg_get(struct blkcg_gq *blkg) { } | |
376 | static inline void blkg_put(struct blkcg_gq *blkg) { } | |
afc24d49 | 377 | |
36558c8a TH |
378 | #endif /* CONFIG_BLK_CGROUP */ |
379 | #endif /* _BLK_CGROUP_H */ |