blob: 1610b22edf0992da4cdeb1657688527d5867e76c [file] [log] [blame]
Vivek Goyal31e4c282009-12-03 12:59:42 -05001#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>
Vivek Goyal575969a2011-05-19 15:38:29 -040017#include <linux/u64_stats_sync.h>
Tejun Heo829fdb52012-04-01 14:38:43 -070018#include <linux/seq_file.h>
Tejun Heoa6371202012-04-19 16:29:24 -070019#include <linux/radix-tree.h>
Tejun Heoa0516612012-06-26 15:05:44 -070020#include <linux/blkdev.h>
Vivek Goyal31e4c282009-12-03 12:59:42 -050021
Vivek Goyal9355aed2010-10-01 21:16:41 +020022/* Max limits for throttle policy */
23#define THROTL_IOPS_MAX UINT_MAX
24
Tejun Heo3381cb82012-04-01 14:38:44 -070025/* CFQ specific, out here for blkcg->cfq_weight */
26#define CFQ_WEIGHT_MIN 10
27#define CFQ_WEIGHT_MAX 1000
28#define CFQ_WEIGHT_DEFAULT 500
29
Tejun Heof48ec1d2012-04-13 13:11:25 -070030#ifdef CONFIG_BLK_CGROUP
31
Tejun Heoedcb0722012-04-01 14:38:42 -070032enum blkg_rwstat_type {
33 BLKG_RWSTAT_READ,
34 BLKG_RWSTAT_WRITE,
35 BLKG_RWSTAT_SYNC,
36 BLKG_RWSTAT_ASYNC,
37
38 BLKG_RWSTAT_NR,
39 BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
Divyesh Shah303a3ac2010-04-01 15:01:24 -070040};
41
Tejun Heoa6371202012-04-19 16:29:24 -070042struct blkcg_gq;
43
Tejun Heo3c798392012-04-16 13:57:25 -070044struct blkcg {
Tejun Heo36558c82012-04-16 13:57:24 -070045 struct cgroup_subsys_state css;
46 spinlock_t lock;
Tejun Heoa6371202012-04-19 16:29:24 -070047
48 struct radix_tree_root blkg_tree;
49 struct blkcg_gq *blkg_hint;
Tejun Heo36558c82012-04-16 13:57:24 -070050 struct hlist_head blkg_list;
Tejun Heo9a9e8a22012-03-19 15:10:56 -070051
52 /* for policies to test whether associated blkcg has changed */
Tejun Heo36558c82012-04-16 13:57:24 -070053 uint64_t id;
Tejun Heo3381cb82012-04-01 14:38:44 -070054
Tejun Heo3c798392012-04-16 13:57:25 -070055 /* TODO: per-policy storage in blkcg */
Tejun Heo36558c82012-04-16 13:57:24 -070056 unsigned int cfq_weight; /* belongs to cfq */
Tejun Heoe71357e2013-01-09 08:05:10 -080057 unsigned int cfq_leaf_weight;
Vivek Goyal31e4c282009-12-03 12:59:42 -050058};
59
Tejun Heoedcb0722012-04-01 14:38:42 -070060struct blkg_stat {
61 struct u64_stats_sync syncp;
62 uint64_t cnt;
63};
64
65struct blkg_rwstat {
66 struct u64_stats_sync syncp;
67 uint64_t cnt[BLKG_RWSTAT_NR];
68};
69
Tejun Heof95a04a2012-04-16 13:57:26 -070070/*
71 * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
72 * request_queue (q). This is used by blkcg policies which need to track
73 * information per blkcg - q pair.
74 *
75 * There can be multiple active blkcg policies and each has its private
76 * data on each blkg, the size of which is determined by
77 * blkcg_policy->pd_size. blkcg core allocates and frees such areas
78 * together with blkg and invokes pd_init/exit_fn() methods.
79 *
80 * Such private data must embed struct blkg_policy_data (pd) at the
81 * beginning and pd_size can't be smaller than pd.
82 */
Tejun Heo03814112012-03-05 13:15:14 -080083struct blkg_policy_data {
Tejun Heob276a872013-01-09 08:05:12 -080084 /* the blkg and policy id this per-policy data belongs to */
Tejun Heo3c798392012-04-16 13:57:25 -070085 struct blkcg_gq *blkg;
Tejun Heob276a872013-01-09 08:05:12 -080086 int plid;
Tejun Heo03814112012-03-05 13:15:14 -080087
Tejun Heoa2b16932012-04-13 13:11:33 -070088 /* used during policy activation */
Tejun Heo36558c82012-04-16 13:57:24 -070089 struct list_head alloc_node;
Tejun Heo03814112012-03-05 13:15:14 -080090};
91
Tejun Heo3c798392012-04-16 13:57:25 -070092/* association between a blk cgroup and a request queue */
93struct blkcg_gq {
Tejun Heoc875f4d2012-03-05 13:15:22 -080094 /* Pointer to the associated request_queue */
Tejun Heo36558c82012-04-16 13:57:24 -070095 struct request_queue *q;
96 struct list_head q_node;
97 struct hlist_node blkcg_node;
Tejun Heo3c798392012-04-16 13:57:25 -070098 struct blkcg *blkcg;
Tejun Heo3c547862013-01-09 08:05:10 -080099
100 /* all non-root blkcg_gq's are guaranteed to have access to parent */
101 struct blkcg_gq *parent;
102
Tejun Heoa0516612012-06-26 15:05:44 -0700103 /* request allocation list for this blkcg-q pair */
104 struct request_list rl;
Tejun Heo3c547862013-01-09 08:05:10 -0800105
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800106 /* reference count */
Tejun Heo36558c82012-04-16 13:57:24 -0700107 int refcnt;
Vivek Goyal22084192009-12-03 12:59:49 -0500108
Tejun Heof427d902013-01-09 08:05:12 -0800109 /* is this blkg online? protected by both blkcg and q locks */
110 bool online;
111
Tejun Heo36558c82012-04-16 13:57:24 -0700112 struct blkg_policy_data *pd[BLKCG_MAX_POLS];
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800113
Tejun Heo36558c82012-04-16 13:57:24 -0700114 struct rcu_head rcu_head;
Vivek Goyal31e4c282009-12-03 12:59:42 -0500115};
116
Tejun Heo3c798392012-04-16 13:57:25 -0700117typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
Tejun Heof427d902013-01-09 08:05:12 -0800118typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
119typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
Tejun Heo3c798392012-04-16 13:57:25 -0700120typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
121typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
Vivek Goyal3e252062009-12-04 10:36:42 -0500122
Tejun Heo3c798392012-04-16 13:57:25 -0700123struct blkcg_policy {
Tejun Heo36558c82012-04-16 13:57:24 -0700124 int plid;
125 /* policy specific private data size */
Tejun Heof95a04a2012-04-16 13:57:26 -0700126 size_t pd_size;
Tejun Heo36558c82012-04-16 13:57:24 -0700127 /* cgroup files for the policy */
128 struct cftype *cftypes;
Tejun Heof9fcc2d2012-04-16 13:57:27 -0700129
130 /* operations */
131 blkcg_pol_init_pd_fn *pd_init_fn;
Tejun Heof427d902013-01-09 08:05:12 -0800132 blkcg_pol_online_pd_fn *pd_online_fn;
133 blkcg_pol_offline_pd_fn *pd_offline_fn;
Tejun Heof9fcc2d2012-04-16 13:57:27 -0700134 blkcg_pol_exit_pd_fn *pd_exit_fn;
135 blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
Vivek Goyal3e252062009-12-04 10:36:42 -0500136};
137
Tejun Heo3c798392012-04-16 13:57:25 -0700138extern struct blkcg blkcg_root;
Tejun Heo36558c82012-04-16 13:57:24 -0700139
Tejun Heo3c798392012-04-16 13:57:25 -0700140struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
141struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
142 struct request_queue *q);
Tejun Heo36558c82012-04-16 13:57:24 -0700143int blkcg_init_queue(struct request_queue *q);
144void blkcg_drain_queue(struct request_queue *q);
145void blkcg_exit_queue(struct request_queue *q);
Tejun Heo5efd6112012-03-05 13:15:12 -0800146
Vivek Goyal3e252062009-12-04 10:36:42 -0500147/* Blkio controller policy registration */
Tejun Heo3c798392012-04-16 13:57:25 -0700148int blkcg_policy_register(struct blkcg_policy *pol);
149void blkcg_policy_unregister(struct blkcg_policy *pol);
Tejun Heo36558c82012-04-16 13:57:24 -0700150int blkcg_activate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700151 const struct blkcg_policy *pol);
Tejun Heo36558c82012-04-16 13:57:24 -0700152void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700153 const struct blkcg_policy *pol);
Vivek Goyal3e252062009-12-04 10:36:42 -0500154
Tejun Heo3c798392012-04-16 13:57:25 -0700155void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
Tejun Heof95a04a2012-04-16 13:57:26 -0700156 u64 (*prfill)(struct seq_file *,
157 struct blkg_policy_data *, int),
Tejun Heo3c798392012-04-16 13:57:25 -0700158 const struct blkcg_policy *pol, int data,
Tejun Heoec399342012-04-13 13:11:27 -0700159 bool show_total);
Tejun Heof95a04a2012-04-16 13:57:26 -0700160u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
161u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
Tejun Heo829fdb52012-04-01 14:38:43 -0700162 const struct blkg_rwstat *rwstat);
Tejun Heof95a04a2012-04-16 13:57:26 -0700163u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
164u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
165 int off);
Tejun Heo829fdb52012-04-01 14:38:43 -0700166
Tejun Heo16b3de62013-01-09 08:05:12 -0800167u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
168struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
169 int off);
170
Tejun Heo829fdb52012-04-01 14:38:43 -0700171struct blkg_conf_ctx {
Tejun Heo36558c82012-04-16 13:57:24 -0700172 struct gendisk *disk;
Tejun Heo3c798392012-04-16 13:57:25 -0700173 struct blkcg_gq *blkg;
Tejun Heo36558c82012-04-16 13:57:24 -0700174 u64 v;
Tejun Heo829fdb52012-04-01 14:38:43 -0700175};
176
Tejun Heo3c798392012-04-16 13:57:25 -0700177int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
178 const char *input, struct blkg_conf_ctx *ctx);
Tejun Heo829fdb52012-04-01 14:38:43 -0700179void blkg_conf_finish(struct blkg_conf_ctx *ctx);
180
181
Tejun Heoa7c6d552013-08-08 20:11:23 -0400182static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
183{
184 return css ? container_of(css, struct blkcg, css) : NULL;
185}
186
Tejun Heob1208b52012-06-04 20:40:57 -0700187static inline struct blkcg *task_blkcg(struct task_struct *tsk)
188{
Tejun Heoa7c6d552013-08-08 20:11:23 -0400189 return css_to_blkcg(task_css(tsk, blkio_subsys_id));
Tejun Heob1208b52012-06-04 20:40:57 -0700190}
191
192static inline struct blkcg *bio_blkcg(struct bio *bio)
193{
194 if (bio && bio->bi_css)
Tejun Heoa7c6d552013-08-08 20:11:23 -0400195 return css_to_blkcg(bio->bi_css);
Tejun Heob1208b52012-06-04 20:40:57 -0700196 return task_blkcg(current);
197}
198
Tejun Heo03814112012-03-05 13:15:14 -0800199/**
Tejun Heo3c547862013-01-09 08:05:10 -0800200 * blkcg_parent - get the parent of a blkcg
201 * @blkcg: blkcg of interest
202 *
203 * Return the parent blkcg of @blkcg. Can be called anytime.
204 */
205static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
206{
Tejun Heo63876982013-08-08 20:11:23 -0400207 return css_to_blkcg(css_parent(&blkcg->css));
Tejun Heo3c547862013-01-09 08:05:10 -0800208}
209
210/**
Tejun Heo03814112012-03-05 13:15:14 -0800211 * blkg_to_pdata - get policy private data
212 * @blkg: blkg of interest
213 * @pol: policy of interest
214 *
215 * Return pointer to private data associated with the @blkg-@pol pair.
216 */
Tejun Heof95a04a2012-04-16 13:57:26 -0700217static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
218 struct blkcg_policy *pol)
Tejun Heo03814112012-03-05 13:15:14 -0800219{
Tejun Heof95a04a2012-04-16 13:57:26 -0700220 return blkg ? blkg->pd[pol->plid] : NULL;
Tejun Heo03814112012-03-05 13:15:14 -0800221}
222
223/**
224 * pdata_to_blkg - get blkg associated with policy private data
Tejun Heof95a04a2012-04-16 13:57:26 -0700225 * @pd: policy private data of interest
Tejun Heo03814112012-03-05 13:15:14 -0800226 *
Tejun Heof95a04a2012-04-16 13:57:26 -0700227 * @pd is policy private data. Determine the blkg it's associated with.
Tejun Heo03814112012-03-05 13:15:14 -0800228 */
Tejun Heof95a04a2012-04-16 13:57:26 -0700229static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
Tejun Heo03814112012-03-05 13:15:14 -0800230{
Tejun Heof95a04a2012-04-16 13:57:26 -0700231 return pd ? pd->blkg : NULL;
Tejun Heo03814112012-03-05 13:15:14 -0800232}
233
Tejun Heo54e7ed12012-04-16 13:57:23 -0700234/**
235 * blkg_path - format cgroup path of blkg
236 * @blkg: blkg of interest
237 * @buf: target buffer
238 * @buflen: target buffer length
239 *
240 * Format the path of the cgroup of @blkg into @buf.
241 */
Tejun Heo3c798392012-04-16 13:57:25 -0700242static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
Vivek Goyalafc24d42010-04-26 19:27:56 +0200243{
Tejun Heo54e7ed12012-04-16 13:57:23 -0700244 int ret;
245
Tejun Heo54e7ed12012-04-16 13:57:23 -0700246 ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
Tejun Heo54e7ed12012-04-16 13:57:23 -0700247 if (ret)
248 strncpy(buf, "<unavailable>", buflen);
249 return ret;
Vivek Goyalafc24d42010-04-26 19:27:56 +0200250}
251
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800252/**
253 * blkg_get - get a blkg reference
254 * @blkg: blkg to get
255 *
256 * The caller should be holding queue_lock and an existing reference.
257 */
Tejun Heo3c798392012-04-16 13:57:25 -0700258static inline void blkg_get(struct blkcg_gq *blkg)
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800259{
260 lockdep_assert_held(blkg->q->queue_lock);
261 WARN_ON_ONCE(!blkg->refcnt);
262 blkg->refcnt++;
263}
264
Tejun Heo2a4fd072013-05-14 13:52:31 -0700265void __blkg_release_rcu(struct rcu_head *rcu);
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800266
267/**
268 * blkg_put - put a blkg reference
269 * @blkg: blkg to put
270 *
271 * The caller should be holding queue_lock.
272 */
Tejun Heo3c798392012-04-16 13:57:25 -0700273static inline void blkg_put(struct blkcg_gq *blkg)
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800274{
275 lockdep_assert_held(blkg->q->queue_lock);
276 WARN_ON_ONCE(blkg->refcnt <= 0);
277 if (!--blkg->refcnt)
Tejun Heo2a4fd072013-05-14 13:52:31 -0700278 call_rcu(&blkg->rcu_head, __blkg_release_rcu);
Tejun Heo1adaf3d2012-03-05 13:15:15 -0800279}
280
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700281struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
282 bool update_hint);
283
284/**
285 * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
286 * @d_blkg: loop cursor pointing to the current descendant
Tejun Heo492eb212013-08-08 20:11:25 -0400287 * @pos_css: used for iteration
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700288 * @p_blkg: target blkg to walk descendants of
289 *
290 * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
291 * read locked. If called under either blkcg or queue lock, the iteration
292 * is guaranteed to include all and only online blkgs. The caller may
Tejun Heo492eb212013-08-08 20:11:25 -0400293 * update @pos_css by calling css_rightmost_descendant() to skip subtree.
Tejun Heobd8815a2013-08-08 20:11:27 -0400294 * @p_blkg is included in the iteration and the first node to be visited.
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700295 */
Tejun Heo492eb212013-08-08 20:11:25 -0400296#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
297 css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
298 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
Tejun Heodd4a4ff2013-05-14 13:52:30 -0700299 (p_blkg)->q, false)))
300
Tejun Heoedcb0722012-04-01 14:38:42 -0700301/**
Tejun Heoaa539cb2013-05-14 13:52:31 -0700302 * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
303 * @d_blkg: loop cursor pointing to the current descendant
Tejun Heo492eb212013-08-08 20:11:25 -0400304 * @pos_css: used for iteration
Tejun Heoaa539cb2013-05-14 13:52:31 -0700305 * @p_blkg: target blkg to walk descendants of
306 *
307 * Similar to blkg_for_each_descendant_pre() but performs post-order
Tejun Heobd8815a2013-08-08 20:11:27 -0400308 * traversal instead. Synchronization rules are the same. @p_blkg is
309 * included in the iteration and the last node to be visited.
Tejun Heoaa539cb2013-05-14 13:52:31 -0700310 */
Tejun Heo492eb212013-08-08 20:11:25 -0400311#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
312 css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
313 if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
Tejun Heoaa539cb2013-05-14 13:52:31 -0700314 (p_blkg)->q, false)))
315
316/**
Tejun Heoa0516612012-06-26 15:05:44 -0700317 * blk_get_rl - get request_list to use
318 * @q: request_queue of interest
319 * @bio: bio which will be attached to the allocated request (may be %NULL)
320 *
321 * The caller wants to allocate a request from @q to use for @bio. Find
322 * the request_list to use and obtain a reference on it. Should be called
323 * under queue_lock. This function is guaranteed to return non-%NULL
324 * request_list.
325 */
326static inline struct request_list *blk_get_rl(struct request_queue *q,
327 struct bio *bio)
328{
329 struct blkcg *blkcg;
330 struct blkcg_gq *blkg;
331
332 rcu_read_lock();
333
334 blkcg = bio_blkcg(bio);
335
336 /* bypass blkg lookup and use @q->root_rl directly for root */
337 if (blkcg == &blkcg_root)
338 goto root_rl;
339
340 /*
341 * Try to use blkg->rl. blkg lookup may fail under memory pressure
342 * or if either the blkcg or queue is going away. Fall back to
343 * root_rl in such cases.
344 */
345 blkg = blkg_lookup_create(blkcg, q);
346 if (unlikely(IS_ERR(blkg)))
347 goto root_rl;
348
349 blkg_get(blkg);
350 rcu_read_unlock();
351 return &blkg->rl;
352root_rl:
353 rcu_read_unlock();
354 return &q->root_rl;
355}
356
357/**
358 * blk_put_rl - put request_list
359 * @rl: request_list to put
360 *
361 * Put the reference acquired by blk_get_rl(). Should be called under
362 * queue_lock.
363 */
364static inline void blk_put_rl(struct request_list *rl)
365{
366 /* root_rl may not have blkg set */
367 if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
368 blkg_put(rl->blkg);
369}
370
371/**
372 * blk_rq_set_rl - associate a request with a request_list
373 * @rq: request of interest
374 * @rl: target request_list
375 *
376 * Associate @rq with @rl so that accounting and freeing can know the
377 * request_list @rq came from.
378 */
379static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
380{
381 rq->rl = rl;
382}
383
384/**
385 * blk_rq_rl - return the request_list a request came from
386 * @rq: request of interest
387 *
388 * Return the request_list @rq is allocated from.
389 */
390static inline struct request_list *blk_rq_rl(struct request *rq)
391{
392 return rq->rl;
393}
394
395struct request_list *__blk_queue_next_rl(struct request_list *rl,
396 struct request_queue *q);
397/**
398 * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
399 *
400 * Should be used under queue_lock.
401 */
402#define blk_queue_for_each_rl(rl, q) \
403 for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
404
Peter Zijlstra90d38392013-11-12 19:42:14 -0800405static inline void blkg_stat_init(struct blkg_stat *stat)
406{
407 u64_stats_init(&stat->syncp);
408}
409
Tejun Heoa0516612012-06-26 15:05:44 -0700410/**
Tejun Heoedcb0722012-04-01 14:38:42 -0700411 * blkg_stat_add - add a value to a blkg_stat
412 * @stat: target blkg_stat
413 * @val: value to add
414 *
415 * Add @val to @stat. The caller is responsible for synchronizing calls to
416 * this function.
417 */
418static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
419{
420 u64_stats_update_begin(&stat->syncp);
421 stat->cnt += val;
422 u64_stats_update_end(&stat->syncp);
423}
424
425/**
426 * blkg_stat_read - read the current value of a blkg_stat
427 * @stat: blkg_stat to read
428 *
429 * Read the current value of @stat. This function can be called without
430 * synchroniztion and takes care of u64 atomicity.
431 */
432static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
433{
434 unsigned int start;
435 uint64_t v;
436
437 do {
438 start = u64_stats_fetch_begin(&stat->syncp);
439 v = stat->cnt;
440 } while (u64_stats_fetch_retry(&stat->syncp, start));
441
442 return v;
443}
444
445/**
446 * blkg_stat_reset - reset a blkg_stat
447 * @stat: blkg_stat to reset
448 */
449static inline void blkg_stat_reset(struct blkg_stat *stat)
450{
451 stat->cnt = 0;
452}
453
454/**
Tejun Heo16b3de62013-01-09 08:05:12 -0800455 * blkg_stat_merge - merge a blkg_stat into another
456 * @to: the destination blkg_stat
457 * @from: the source
458 *
459 * Add @from's count to @to.
460 */
461static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
462{
463 blkg_stat_add(to, blkg_stat_read(from));
464}
465
Peter Zijlstra90d38392013-11-12 19:42:14 -0800466static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat)
467{
468 u64_stats_init(&rwstat->syncp);
469}
470
Tejun Heo16b3de62013-01-09 08:05:12 -0800471/**
Tejun Heoedcb0722012-04-01 14:38:42 -0700472 * blkg_rwstat_add - add a value to a blkg_rwstat
473 * @rwstat: target blkg_rwstat
474 * @rw: mask of REQ_{WRITE|SYNC}
475 * @val: value to add
476 *
477 * Add @val to @rwstat. The counters are chosen according to @rw. The
478 * caller is responsible for synchronizing calls to this function.
479 */
480static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
481 int rw, uint64_t val)
482{
483 u64_stats_update_begin(&rwstat->syncp);
484
485 if (rw & REQ_WRITE)
486 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
487 else
488 rwstat->cnt[BLKG_RWSTAT_READ] += val;
489 if (rw & REQ_SYNC)
490 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
491 else
492 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
493
494 u64_stats_update_end(&rwstat->syncp);
495}
496
497/**
498 * blkg_rwstat_read - read the current values of a blkg_rwstat
499 * @rwstat: blkg_rwstat to read
500 *
501 * Read the current snapshot of @rwstat and return it as the return value.
502 * This function can be called without synchronization and takes care of
503 * u64 atomicity.
504 */
Tejun Heoc94bed892012-04-16 13:57:22 -0700505static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
Tejun Heoedcb0722012-04-01 14:38:42 -0700506{
507 unsigned int start;
508 struct blkg_rwstat tmp;
509
510 do {
511 start = u64_stats_fetch_begin(&rwstat->syncp);
512 tmp = *rwstat;
513 } while (u64_stats_fetch_retry(&rwstat->syncp, start));
514
515 return tmp;
516}
517
518/**
Tejun Heo4d5e80a2013-01-09 08:05:12 -0800519 * blkg_rwstat_total - read the total count of a blkg_rwstat
Tejun Heoedcb0722012-04-01 14:38:42 -0700520 * @rwstat: blkg_rwstat to read
521 *
522 * Return the total count of @rwstat regardless of the IO direction. This
523 * function can be called without synchronization and takes care of u64
524 * atomicity.
525 */
Tejun Heo4d5e80a2013-01-09 08:05:12 -0800526static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
Tejun Heoedcb0722012-04-01 14:38:42 -0700527{
528 struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
529
530 return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
531}
532
533/**
534 * blkg_rwstat_reset - reset a blkg_rwstat
535 * @rwstat: blkg_rwstat to reset
536 */
537static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
538{
539 memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
540}
541
Tejun Heo16b3de62013-01-09 08:05:12 -0800542/**
543 * blkg_rwstat_merge - merge a blkg_rwstat into another
544 * @to: the destination blkg_rwstat
545 * @from: the source
546 *
547 * Add @from's counts to @to.
548 */
549static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
550 struct blkg_rwstat *from)
551{
552 struct blkg_rwstat v = blkg_rwstat_read(from);
553 int i;
554
555 u64_stats_update_begin(&to->syncp);
556 for (i = 0; i < BLKG_RWSTAT_NR; i++)
557 to->cnt[i] += v.cnt[i];
558 u64_stats_update_end(&to->syncp);
559}
560
Tejun Heo36558c82012-04-16 13:57:24 -0700561#else /* CONFIG_BLK_CGROUP */
562
563struct cgroup;
Tejun Heob1208b52012-06-04 20:40:57 -0700564struct blkcg;
Jens Axboe2f5ea472009-12-03 21:06:43 +0100565
Tejun Heof95a04a2012-04-16 13:57:26 -0700566struct blkg_policy_data {
567};
568
Tejun Heo3c798392012-04-16 13:57:25 -0700569struct blkcg_gq {
Jens Axboe2f5ea472009-12-03 21:06:43 +0100570};
571
Tejun Heo3c798392012-04-16 13:57:25 -0700572struct blkcg_policy {
Vivek Goyal3e252062009-12-04 10:36:42 -0500573};
574
Tejun Heo3c798392012-04-16 13:57:25 -0700575static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
Tejun Heo5efd6112012-03-05 13:15:12 -0800576static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
577static inline void blkcg_drain_queue(struct request_queue *q) { }
578static inline void blkcg_exit_queue(struct request_queue *q) { }
Tejun Heo3c798392012-04-16 13:57:25 -0700579static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
580static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
Tejun Heoa2b16932012-04-13 13:11:33 -0700581static inline int blkcg_activate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700582 const struct blkcg_policy *pol) { return 0; }
Tejun Heoa2b16932012-04-13 13:11:33 -0700583static inline void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo3c798392012-04-16 13:57:25 -0700584 const struct blkcg_policy *pol) { }
Vivek Goyal3e252062009-12-04 10:36:42 -0500585
Tejun Heob1208b52012-06-04 20:40:57 -0700586static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
Tejun Heoa0516612012-06-26 15:05:44 -0700587
Tejun Heof95a04a2012-04-16 13:57:26 -0700588static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
589 struct blkcg_policy *pol) { return NULL; }
590static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
Tejun Heo3c798392012-04-16 13:57:25 -0700591static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
592static inline void blkg_get(struct blkcg_gq *blkg) { }
593static inline void blkg_put(struct blkcg_gq *blkg) { }
Vivek Goyalafc24d42010-04-26 19:27:56 +0200594
Tejun Heoa0516612012-06-26 15:05:44 -0700595static inline struct request_list *blk_get_rl(struct request_queue *q,
596 struct bio *bio) { return &q->root_rl; }
597static inline void blk_put_rl(struct request_list *rl) { }
598static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
599static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
600
601#define blk_queue_for_each_rl(rl, q) \
602 for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
603
Tejun Heo36558c82012-04-16 13:57:24 -0700604#endif /* CONFIG_BLK_CGROUP */
605#endif /* _BLK_CGROUP_H */