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 /* cft->private [un]packing for stat printing */
38 #define BLKCG_STAT_PRIV(pol, off) (((unsigned)(pol) << 16) | (off))
39 #define BLKCG_STAT_POL(prv) ((unsigned)(prv) >> 16)
40 #define BLKCG_STAT_OFF(prv) ((unsigned)(prv) & 0xffff)
42 enum blkg_rwstat_type
{
49 BLKG_RWSTAT_TOTAL
= BLKG_RWSTAT_NR
,
53 struct cgroup_subsys_state css
;
55 struct hlist_head blkg_list
;
57 /* for policies to test whether associated blkcg has changed */
60 /* TODO: per-policy storage in blkio_cgroup */
61 unsigned int cfq_weight
; /* belongs to cfq */
65 struct u64_stats_sync syncp
;
70 struct u64_stats_sync syncp
;
71 uint64_t cnt
[BLKG_RWSTAT_NR
];
74 /* per-blkg per-policy data */
75 struct blkg_policy_data
{
76 /* the blkg this per-policy data belongs to */
77 struct blkio_group
*blkg
;
79 /* pol->pdata_size bytes of private data used by policy impl */
80 char pdata
[] __aligned(__alignof__(unsigned long long));
84 /* Pointer to the associated request_queue */
85 struct request_queue
*q
;
86 struct list_head q_node
;
87 struct hlist_node blkcg_node
;
88 struct blkio_cgroup
*blkcg
;
89 /* Store cgroup path */
94 struct blkg_policy_data
*pd
[BLKIO_NR_POLICIES
];
96 struct rcu_head rcu_head
;
99 typedef void (blkio_init_group_fn
)(struct blkio_group
*blkg
);
100 typedef void (blkio_exit_group_fn
)(struct blkio_group
*blkg
);
101 typedef void (blkio_reset_group_stats_fn
)(struct blkio_group
*blkg
);
103 struct blkio_policy_ops
{
104 blkio_init_group_fn
*blkio_init_group_fn
;
105 blkio_exit_group_fn
*blkio_exit_group_fn
;
106 blkio_reset_group_stats_fn
*blkio_reset_group_stats_fn
;
109 struct blkio_policy_type
{
110 struct list_head list
;
111 struct blkio_policy_ops ops
;
112 enum blkio_policy_id plid
;
113 size_t pdata_size
; /* policy specific private data size */
114 struct cftype
*cftypes
; /* cgroup files for the policy */
117 extern int blkcg_init_queue(struct request_queue
*q
);
118 extern void blkcg_drain_queue(struct request_queue
*q
);
119 extern void blkcg_exit_queue(struct request_queue
*q
);
121 /* Blkio controller policy registration */
122 extern void blkio_policy_register(struct blkio_policy_type
*);
123 extern void blkio_policy_unregister(struct blkio_policy_type
*);
124 extern void blkg_destroy_all(struct request_queue
*q
, bool destroy_root
);
125 extern void update_root_blkg_pd(struct request_queue
*q
,
126 enum blkio_policy_id plid
);
128 void blkcg_print_blkgs(struct seq_file
*sf
, struct blkio_cgroup
*blkcg
,
129 u64 (*prfill
)(struct seq_file
*, struct blkg_policy_data
*, int),
130 int pol
, int data
, bool show_total
);
131 u64
__blkg_prfill_u64(struct seq_file
*sf
, struct blkg_policy_data
*pd
, u64 v
);
132 u64
__blkg_prfill_rwstat(struct seq_file
*sf
, struct blkg_policy_data
*pd
,
133 const struct blkg_rwstat
*rwstat
);
134 int blkcg_print_stat(struct cgroup
*cgrp
, struct cftype
*cft
,
135 struct seq_file
*sf
);
136 int blkcg_print_rwstat(struct cgroup
*cgrp
, struct cftype
*cft
,
137 struct seq_file
*sf
);
139 struct blkg_conf_ctx
{
140 struct gendisk
*disk
;
141 struct blkio_group
*blkg
;
145 int blkg_conf_prep(struct blkio_cgroup
*blkcg
, const char *input
,
146 struct blkg_conf_ctx
*ctx
);
147 void blkg_conf_finish(struct blkg_conf_ctx
*ctx
);
151 * blkg_to_pdata - get policy private data
152 * @blkg: blkg of interest
153 * @pol: policy of interest
155 * Return pointer to private data associated with the @blkg-@pol pair.
157 static inline void *blkg_to_pdata(struct blkio_group
*blkg
,
158 struct blkio_policy_type
*pol
)
160 return blkg
? blkg
->pd
[pol
->plid
]->pdata
: NULL
;
164 * pdata_to_blkg - get blkg associated with policy private data
165 * @pdata: policy private data of interest
167 * @pdata is policy private data. Determine the blkg it's associated with.
169 static inline struct blkio_group
*pdata_to_blkg(void *pdata
)
172 struct blkg_policy_data
*pd
=
173 container_of(pdata
, struct blkg_policy_data
, pdata
);
179 static inline char *blkg_path(struct blkio_group
*blkg
)
185 * blkg_get - get a blkg reference
188 * The caller should be holding queue_lock and an existing reference.
190 static inline void blkg_get(struct blkio_group
*blkg
)
192 lockdep_assert_held(blkg
->q
->queue_lock
);
193 WARN_ON_ONCE(!blkg
->refcnt
);
197 void __blkg_release(struct blkio_group
*blkg
);
200 * blkg_put - put a blkg reference
203 * The caller should be holding queue_lock.
205 static inline void blkg_put(struct blkio_group
*blkg
)
207 lockdep_assert_held(blkg
->q
->queue_lock
);
208 WARN_ON_ONCE(blkg
->refcnt
<= 0);
210 __blkg_release(blkg
);
214 * blkg_stat_add - add a value to a blkg_stat
215 * @stat: target blkg_stat
218 * Add @val to @stat. The caller is responsible for synchronizing calls to
221 static inline void blkg_stat_add(struct blkg_stat
*stat
, uint64_t val
)
223 u64_stats_update_begin(&stat
->syncp
);
225 u64_stats_update_end(&stat
->syncp
);
229 * blkg_stat_read - read the current value of a blkg_stat
230 * @stat: blkg_stat to read
232 * Read the current value of @stat. This function can be called without
233 * synchroniztion and takes care of u64 atomicity.
235 static inline uint64_t blkg_stat_read(struct blkg_stat
*stat
)
241 start
= u64_stats_fetch_begin(&stat
->syncp
);
243 } while (u64_stats_fetch_retry(&stat
->syncp
, start
));
249 * blkg_stat_reset - reset a blkg_stat
250 * @stat: blkg_stat to reset
252 static inline void blkg_stat_reset(struct blkg_stat
*stat
)
258 * blkg_rwstat_add - add a value to a blkg_rwstat
259 * @rwstat: target blkg_rwstat
260 * @rw: mask of REQ_{WRITE|SYNC}
263 * Add @val to @rwstat. The counters are chosen according to @rw. The
264 * caller is responsible for synchronizing calls to this function.
266 static inline void blkg_rwstat_add(struct blkg_rwstat
*rwstat
,
267 int rw
, uint64_t val
)
269 u64_stats_update_begin(&rwstat
->syncp
);
272 rwstat
->cnt
[BLKG_RWSTAT_WRITE
] += val
;
274 rwstat
->cnt
[BLKG_RWSTAT_READ
] += val
;
276 rwstat
->cnt
[BLKG_RWSTAT_SYNC
] += val
;
278 rwstat
->cnt
[BLKG_RWSTAT_ASYNC
] += val
;
280 u64_stats_update_end(&rwstat
->syncp
);
284 * blkg_rwstat_read - read the current values of a blkg_rwstat
285 * @rwstat: blkg_rwstat to read
287 * Read the current snapshot of @rwstat and return it as the return value.
288 * This function can be called without synchronization and takes care of
291 static struct blkg_rwstat
blkg_rwstat_read(struct blkg_rwstat
*rwstat
)
294 struct blkg_rwstat tmp
;
297 start
= u64_stats_fetch_begin(&rwstat
->syncp
);
299 } while (u64_stats_fetch_retry(&rwstat
->syncp
, start
));
305 * blkg_rwstat_sum - read the total count of a blkg_rwstat
306 * @rwstat: blkg_rwstat to read
308 * Return the total count of @rwstat regardless of the IO direction. This
309 * function can be called without synchronization and takes care of u64
312 static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat
*rwstat
)
314 struct blkg_rwstat tmp
= blkg_rwstat_read(rwstat
);
316 return tmp
.cnt
[BLKG_RWSTAT_READ
] + tmp
.cnt
[BLKG_RWSTAT_WRITE
];
320 * blkg_rwstat_reset - reset a blkg_rwstat
321 * @rwstat: blkg_rwstat to reset
323 static inline void blkg_rwstat_reset(struct blkg_rwstat
*rwstat
)
325 memset(rwstat
->cnt
, 0, sizeof(rwstat
->cnt
));
333 struct blkio_policy_type
{
336 static inline int blkcg_init_queue(struct request_queue
*q
) { return 0; }
337 static inline void blkcg_drain_queue(struct request_queue
*q
) { }
338 static inline void blkcg_exit_queue(struct request_queue
*q
) { }
339 static inline void blkio_policy_register(struct blkio_policy_type
*blkiop
) { }
340 static inline void blkio_policy_unregister(struct blkio_policy_type
*blkiop
) { }
341 static inline void blkg_destroy_all(struct request_queue
*q
,
342 bool destory_root
) { }
343 static inline void update_root_blkg_pd(struct request_queue
*q
,
344 enum blkio_policy_id plid
) { }
346 static inline void *blkg_to_pdata(struct blkio_group
*blkg
,
347 struct blkio_policy_type
*pol
) { return NULL
; }
348 static inline struct blkio_group
*pdata_to_blkg(void *pdata
,
349 struct blkio_policy_type
*pol
) { return NULL
; }
350 static inline char *blkg_path(struct blkio_group
*blkg
) { return NULL
; }
351 static inline void blkg_get(struct blkio_group
*blkg
) { }
352 static inline void blkg_put(struct blkio_group
*blkg
) { }
356 #ifdef CONFIG_BLK_CGROUP
357 extern struct blkio_cgroup blkio_root_cgroup
;
358 extern struct blkio_cgroup
*cgroup_to_blkio_cgroup(struct cgroup
*cgroup
);
359 extern struct blkio_cgroup
*bio_blkio_cgroup(struct bio
*bio
);
360 extern struct blkio_group
*blkg_lookup(struct blkio_cgroup
*blkcg
,
361 struct request_queue
*q
);
362 struct blkio_group
*blkg_lookup_create(struct blkio_cgroup
*blkcg
,
363 struct request_queue
*q
,
367 static inline struct blkio_cgroup
*
368 cgroup_to_blkio_cgroup(struct cgroup
*cgroup
) { return NULL
; }
369 static inline struct blkio_cgroup
*
370 bio_blkio_cgroup(struct bio
*bio
) { return NULL
; }
372 static inline struct blkio_group
*blkg_lookup(struct blkio_cgroup
*blkcg
,
373 void *key
) { return NULL
; }
375 #endif /* _BLK_CGROUP_H */