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 /* Max limits for throttle policy */
21 #define THROTL_IOPS_MAX UINT_MAX
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
28 #ifdef CONFIG_BLK_CGROUP
30 enum blkg_rwstat_type {
37 BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
41 struct cgroup_subsys_state css;
43 struct hlist_head blkg_list;
45 /* for policies to test whether associated blkcg has changed */
48 /* TODO: per-policy storage in blkio_cgroup */
49 unsigned int cfq_weight; /* belongs to cfq */
53 struct u64_stats_sync syncp;
58 struct u64_stats_sync syncp;
59 uint64_t cnt[BLKG_RWSTAT_NR];
62 /* per-blkg per-policy data */
63 struct blkg_policy_data {
64 /* the blkg this per-policy data belongs to */
65 struct blkio_group *blkg;
67 /* pol->pdata_size bytes of private data used by policy impl */
68 char pdata[] __aligned(__alignof__(unsigned long long));
72 /* Pointer to the associated request_queue */
73 struct request_queue *q;
74 struct list_head q_node;
75 struct hlist_node blkcg_node;
76 struct blkio_cgroup *blkcg;
77 /* Store cgroup path */
82 struct blkg_policy_data *pd[BLKCG_MAX_POLS];
84 struct rcu_head rcu_head;
87 typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
88 typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
89 typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);
91 struct blkio_policy_ops {
92 blkio_init_group_fn *blkio_init_group_fn;
93 blkio_exit_group_fn *blkio_exit_group_fn;
94 blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
97 struct blkio_policy_type {
98 struct blkio_policy_ops ops;
100 size_t pdata_size; /* policy specific private data size */
101 struct cftype *cftypes; /* cgroup files for the policy */
104 extern int blkcg_init_queue(struct request_queue *q);
105 extern void blkcg_drain_queue(struct request_queue *q);
106 extern void blkcg_exit_queue(struct request_queue *q);
108 /* Blkio controller policy registration */
109 extern int blkio_policy_register(struct blkio_policy_type *);
110 extern void blkio_policy_unregister(struct blkio_policy_type *);
111 extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
112 extern void update_root_blkg_pd(struct request_queue *q,
113 const struct blkio_policy_type *pol);
115 void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
116 u64 (*prfill)(struct seq_file *, void *, int),
117 const struct blkio_policy_type *pol, int data,
119 u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v);
120 u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
121 const struct blkg_rwstat *rwstat);
122 u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off);
123 u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, int off);
125 struct blkg_conf_ctx {
126 struct gendisk *disk;
127 struct blkio_group *blkg;
131 int blkg_conf_prep(struct blkio_cgroup *blkcg,
132 const struct blkio_policy_type *pol, const char *input,
133 struct blkg_conf_ctx *ctx);
134 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
138 * blkg_to_pdata - get policy private data
139 * @blkg: blkg of interest
140 * @pol: policy of interest
142 * Return pointer to private data associated with the @blkg-@pol pair.
144 static inline void *blkg_to_pdata(struct blkio_group *blkg,
145 struct blkio_policy_type *pol)
147 return blkg ? blkg->pd[pol->plid]->pdata : NULL;
151 * pdata_to_blkg - get blkg associated with policy private data
152 * @pdata: policy private data of interest
154 * @pdata is policy private data. Determine the blkg it's associated with.
156 static inline struct blkio_group *pdata_to_blkg(void *pdata)
159 struct blkg_policy_data *pd =
160 container_of(pdata, struct blkg_policy_data, pdata);
166 static inline char *blkg_path(struct blkio_group *blkg)
172 * blkg_get - get a blkg reference
175 * The caller should be holding queue_lock and an existing reference.
177 static inline void blkg_get(struct blkio_group *blkg)
179 lockdep_assert_held(blkg->q->queue_lock);
180 WARN_ON_ONCE(!blkg->refcnt);
184 void __blkg_release(struct blkio_group *blkg);
187 * blkg_put - put a blkg reference
190 * The caller should be holding queue_lock.
192 static inline void blkg_put(struct blkio_group *blkg)
194 lockdep_assert_held(blkg->q->queue_lock);
195 WARN_ON_ONCE(blkg->refcnt <= 0);
197 __blkg_release(blkg);
201 * blkg_stat_add - add a value to a blkg_stat
202 * @stat: target blkg_stat
205 * Add @val to @stat. The caller is responsible for synchronizing calls to
208 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
210 u64_stats_update_begin(&stat->syncp);
212 u64_stats_update_end(&stat->syncp);
216 * blkg_stat_read - read the current value of a blkg_stat
217 * @stat: blkg_stat to read
219 * Read the current value of @stat. This function can be called without
220 * synchroniztion and takes care of u64 atomicity.
222 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
228 start = u64_stats_fetch_begin(&stat->syncp);
230 } while (u64_stats_fetch_retry(&stat->syncp, start));
236 * blkg_stat_reset - reset a blkg_stat
237 * @stat: blkg_stat to reset
239 static inline void blkg_stat_reset(struct blkg_stat *stat)
245 * blkg_rwstat_add - add a value to a blkg_rwstat
246 * @rwstat: target blkg_rwstat
247 * @rw: mask of REQ_{WRITE|SYNC}
250 * Add @val to @rwstat. The counters are chosen according to @rw. The
251 * caller is responsible for synchronizing calls to this function.
253 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
254 int rw, uint64_t val)
256 u64_stats_update_begin(&rwstat->syncp);
259 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
261 rwstat->cnt[BLKG_RWSTAT_READ] += val;
263 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
265 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
267 u64_stats_update_end(&rwstat->syncp);
271 * blkg_rwstat_read - read the current values of a blkg_rwstat
272 * @rwstat: blkg_rwstat to read
274 * Read the current snapshot of @rwstat and return it as the return value.
275 * This function can be called without synchronization and takes care of
278 static struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
281 struct blkg_rwstat tmp;
284 start = u64_stats_fetch_begin(&rwstat->syncp);
286 } while (u64_stats_fetch_retry(&rwstat->syncp, start));
292 * blkg_rwstat_sum - read the total count of a blkg_rwstat
293 * @rwstat: blkg_rwstat to read
295 * Return the total count of @rwstat regardless of the IO direction. This
296 * function can be called without synchronization and takes care of u64
299 static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
301 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
303 return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
307 * blkg_rwstat_reset - reset a blkg_rwstat
308 * @rwstat: blkg_rwstat to reset
310 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
312 memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
320 struct blkio_policy_type {
323 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
324 static inline void blkcg_drain_queue(struct request_queue *q) { }
325 static inline void blkcg_exit_queue(struct request_queue *q) { }
326 static inline int blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; }
327 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
328 static inline void blkg_destroy_all(struct request_queue *q,
329 bool destory_root) { }
330 static inline void update_root_blkg_pd(struct request_queue *q,
331 const struct blkio_policy_type *pol) { }
333 static inline void *blkg_to_pdata(struct blkio_group *blkg,
334 struct blkio_policy_type *pol) { return NULL; }
335 static inline struct blkio_group *pdata_to_blkg(void *pdata,
336 struct blkio_policy_type *pol) { return NULL; }
337 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
338 static inline void blkg_get(struct blkio_group *blkg) { }
339 static inline void blkg_put(struct blkio_group *blkg) { }
343 #ifdef CONFIG_BLK_CGROUP
344 extern struct blkio_cgroup blkio_root_cgroup;
345 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
346 extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
347 extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
348 struct request_queue *q);
349 struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
350 struct request_queue *q,
354 static inline struct blkio_cgroup *
355 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
356 static inline struct blkio_cgroup *
357 bio_blkio_cgroup(struct bio *bio) { return NULL; }
359 static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
360 void *key) { return NULL; }
362 #endif /* _BLK_CGROUP_H */