4 * Common Block IO controller cgroup interface
6 * Based on ideas and code from CFQ, CFS and BFQ:
7 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
9 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
10 * Paolo Valente <paolo.valente@unimore.it>
12 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
13 * Nauman Rafique <nauman@google.com>
16 #include <linux/cgroup.h>
17 #include <linux/u64_stats_sync.h>
18 #include <linux/seq_file.h>
20 enum blkio_policy_id {
21 BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */
22 BLKIO_POLICY_THROTL, /* Throttling */
27 /* Max limits for throttle policy */
28 #define THROTL_IOPS_MAX UINT_MAX
30 #ifdef CONFIG_BLK_CGROUP
32 /* CFQ specific, out here for blkcg->cfq_weight */
33 #define CFQ_WEIGHT_MIN 10
34 #define CFQ_WEIGHT_MAX 1000
35 #define CFQ_WEIGHT_DEFAULT 500
37 enum blkg_rwstat_type {
44 BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
48 struct cgroup_subsys_state css;
50 struct hlist_head blkg_list;
52 /* for policies to test whether associated blkcg has changed */
55 /* TODO: per-policy storage in blkio_cgroup */
56 unsigned int cfq_weight; /* belongs to cfq */
60 struct u64_stats_sync syncp;
65 struct u64_stats_sync syncp;
66 uint64_t cnt[BLKG_RWSTAT_NR];
69 /* per-blkg per-policy data */
70 struct blkg_policy_data {
71 /* the blkg this per-policy data belongs to */
72 struct blkio_group *blkg;
74 /* pol->pdata_size bytes of private data used by policy impl */
75 char pdata[] __aligned(__alignof__(unsigned long long));
79 /* Pointer to the associated request_queue */
80 struct request_queue *q;
81 struct list_head q_node;
82 struct hlist_node blkcg_node;
83 struct blkio_cgroup *blkcg;
84 /* Store cgroup path */
89 struct blkg_policy_data *pd[BLKIO_NR_POLICIES];
91 struct rcu_head rcu_head;
94 typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
95 typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
96 typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);
98 struct blkio_policy_ops {
99 blkio_init_group_fn *blkio_init_group_fn;
100 blkio_exit_group_fn *blkio_exit_group_fn;
101 blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
104 struct blkio_policy_type {
105 struct list_head list;
106 struct blkio_policy_ops ops;
107 enum blkio_policy_id plid;
108 size_t pdata_size; /* policy specific private data size */
109 struct cftype *cftypes; /* cgroup files for the policy */
112 extern int blkcg_init_queue(struct request_queue *q);
113 extern void blkcg_drain_queue(struct request_queue *q);
114 extern void blkcg_exit_queue(struct request_queue *q);
116 /* Blkio controller policy registration */
117 extern void blkio_policy_register(struct blkio_policy_type *);
118 extern void blkio_policy_unregister(struct blkio_policy_type *);
119 extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
120 extern void update_root_blkg_pd(struct request_queue *q,
121 enum blkio_policy_id plid);
123 void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
124 u64 (*prfill)(struct seq_file *, void *, int),
125 int pol, int data, bool show_total);
126 u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v);
127 u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
128 const struct blkg_rwstat *rwstat);
129 u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off);
130 u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, int off);
132 struct blkg_conf_ctx {
133 struct gendisk *disk;
134 struct blkio_group *blkg;
138 int blkg_conf_prep(struct blkio_cgroup *blkcg, const char *input,
139 struct blkg_conf_ctx *ctx);
140 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
144 * blkg_to_pdata - get policy private data
145 * @blkg: blkg of interest
146 * @pol: policy of interest
148 * Return pointer to private data associated with the @blkg-@pol pair.
150 static inline void *blkg_to_pdata(struct blkio_group *blkg,
151 struct blkio_policy_type *pol)
153 return blkg ? blkg->pd[pol->plid]->pdata : NULL;
157 * pdata_to_blkg - get blkg associated with policy private data
158 * @pdata: policy private data of interest
160 * @pdata is policy private data. Determine the blkg it's associated with.
162 static inline struct blkio_group *pdata_to_blkg(void *pdata)
165 struct blkg_policy_data *pd =
166 container_of(pdata, struct blkg_policy_data, pdata);
172 static inline char *blkg_path(struct blkio_group *blkg)
178 * blkg_get - get a blkg reference
181 * The caller should be holding queue_lock and an existing reference.
183 static inline void blkg_get(struct blkio_group *blkg)
185 lockdep_assert_held(blkg->q->queue_lock);
186 WARN_ON_ONCE(!blkg->refcnt);
190 void __blkg_release(struct blkio_group *blkg);
193 * blkg_put - put a blkg reference
196 * The caller should be holding queue_lock.
198 static inline void blkg_put(struct blkio_group *blkg)
200 lockdep_assert_held(blkg->q->queue_lock);
201 WARN_ON_ONCE(blkg->refcnt <= 0);
203 __blkg_release(blkg);
207 * blkg_stat_add - add a value to a blkg_stat
208 * @stat: target blkg_stat
211 * Add @val to @stat. The caller is responsible for synchronizing calls to
214 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
216 u64_stats_update_begin(&stat->syncp);
218 u64_stats_update_end(&stat->syncp);
222 * blkg_stat_read - read the current value of a blkg_stat
223 * @stat: blkg_stat to read
225 * Read the current value of @stat. This function can be called without
226 * synchroniztion and takes care of u64 atomicity.
228 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
234 start = u64_stats_fetch_begin(&stat->syncp);
236 } while (u64_stats_fetch_retry(&stat->syncp, start));
242 * blkg_stat_reset - reset a blkg_stat
243 * @stat: blkg_stat to reset
245 static inline void blkg_stat_reset(struct blkg_stat *stat)
251 * blkg_rwstat_add - add a value to a blkg_rwstat
252 * @rwstat: target blkg_rwstat
253 * @rw: mask of REQ_{WRITE|SYNC}
256 * Add @val to @rwstat. The counters are chosen according to @rw. The
257 * caller is responsible for synchronizing calls to this function.
259 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
260 int rw, uint64_t val)
262 u64_stats_update_begin(&rwstat->syncp);
265 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
267 rwstat->cnt[BLKG_RWSTAT_READ] += val;
269 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
271 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
273 u64_stats_update_end(&rwstat->syncp);
277 * blkg_rwstat_read - read the current values of a blkg_rwstat
278 * @rwstat: blkg_rwstat to read
280 * Read the current snapshot of @rwstat and return it as the return value.
281 * This function can be called without synchronization and takes care of
284 static struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
287 struct blkg_rwstat tmp;
290 start = u64_stats_fetch_begin(&rwstat->syncp);
292 } while (u64_stats_fetch_retry(&rwstat->syncp, start));
298 * blkg_rwstat_sum - read the total count of a blkg_rwstat
299 * @rwstat: blkg_rwstat to read
301 * Return the total count of @rwstat regardless of the IO direction. This
302 * function can be called without synchronization and takes care of u64
305 static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
307 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
309 return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
313 * blkg_rwstat_reset - reset a blkg_rwstat
314 * @rwstat: blkg_rwstat to reset
316 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
318 memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
326 struct blkio_policy_type {
329 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
330 static inline void blkcg_drain_queue(struct request_queue *q) { }
331 static inline void blkcg_exit_queue(struct request_queue *q) { }
332 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
333 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
334 static inline void blkg_destroy_all(struct request_queue *q,
335 bool destory_root) { }
336 static inline void update_root_blkg_pd(struct request_queue *q,
337 enum blkio_policy_id plid) { }
339 static inline void *blkg_to_pdata(struct blkio_group *blkg,
340 struct blkio_policy_type *pol) { return NULL; }
341 static inline struct blkio_group *pdata_to_blkg(void *pdata,
342 struct blkio_policy_type *pol) { return NULL; }
343 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
344 static inline void blkg_get(struct blkio_group *blkg) { }
345 static inline void blkg_put(struct blkio_group *blkg) { }
349 #ifdef CONFIG_BLK_CGROUP
350 extern struct blkio_cgroup blkio_root_cgroup;
351 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
352 extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
353 extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
354 struct request_queue *q);
355 struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
356 struct request_queue *q,
360 static inline struct blkio_cgroup *
361 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
362 static inline struct blkio_cgroup *
363 bio_blkio_cgroup(struct bio *bio) { return NULL; }
365 static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
366 void *key) { return NULL; }
368 #endif /* _BLK_CGROUP_H */