blk-cgroup.h 21.8 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
#ifndef _BLK_CGROUP_H
#define _BLK_CGROUP_H
/*
 * Common Block IO controller cgroup interface
 *
 * Based on ideas and code from CFQ, CFS and BFQ:
 * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
 *
 * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
 *		      Paolo Valente <paolo.valente@unimore.it>
 *
 * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
 * 	              Nauman Rafique <nauman@google.com>
 */

#include <linux/cgroup.h>
Tejun Heo's avatar
Tejun Heo committed
17
#include <linux/percpu_counter.h>
18
#include <linux/seq_file.h>
19
#include <linux/radix-tree.h>
20
#include <linux/blkdev.h>
21
#include <linux/atomic.h>
22

Tejun Heo's avatar
Tejun Heo committed
23
24
25
/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
#define BLKG_STAT_CPU_BATCH	(INT_MAX / 2)

26
27
28
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX		UINT_MAX

Tejun Heo's avatar
Tejun Heo committed
29
30
#ifdef CONFIG_BLK_CGROUP

31
32
33
34
35
36
37
38
enum blkg_rwstat_type {
	BLKG_RWSTAT_READ,
	BLKG_RWSTAT_WRITE,
	BLKG_RWSTAT_SYNC,
	BLKG_RWSTAT_ASYNC,

	BLKG_RWSTAT_NR,
	BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
39
40
};

41
42
struct blkcg_gq;

Tejun Heo's avatar
Tejun Heo committed
43
struct blkcg {
44
45
	struct cgroup_subsys_state	css;
	spinlock_t			lock;
46
47
48

	struct radix_tree_root		blkg_tree;
	struct blkcg_gq			*blkg_hint;
49
	struct hlist_head		blkg_list;
Tejun Heo's avatar
Tejun Heo committed
50

51
	struct blkcg_policy_data	*cpd[BLKCG_MAX_POLS];
52

Tejun Heo's avatar
Tejun Heo committed
53
	struct list_head		all_blkcgs_node;
54
55
56
#ifdef CONFIG_CGROUP_WRITEBACK
	struct list_head		cgwb_list;
#endif
57
58
};

59
60
/*
 * blkg_[rw]stat->aux_cnt is excluded for local stats but included for
Tejun Heo's avatar
Tejun Heo committed
61
62
 * recursive.  Used to carry stats of dead children, and, for blkg_rwstat,
 * to carry result values from read and sum operations.
63
 */
64
struct blkg_stat {
Tejun Heo's avatar
Tejun Heo committed
65
	struct percpu_counter		cpu_cnt;
66
	atomic64_t			aux_cnt;
67
68
69
};

struct blkg_rwstat {
Tejun Heo's avatar
Tejun Heo committed
70
	struct percpu_counter		cpu_cnt[BLKG_RWSTAT_NR];
71
	atomic64_t			aux_cnt[BLKG_RWSTAT_NR];
72
73
};

74
75
76
77
78
/*
 * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
 * request_queue (q).  This is used by blkcg policies which need to track
 * information per blkcg - q pair.
 *
79
80
81
82
83
 * There can be multiple active blkcg policies and each blkg:policy pair is
 * represented by a blkg_policy_data which is allocated and freed by each
 * policy's pd_alloc/free_fn() methods.  A policy can allocate private data
 * area by allocating larger data structure which embeds blkg_policy_data
 * at the beginning.
84
 */
85
struct blkg_policy_data {
Tejun Heo's avatar
Tejun Heo committed
86
	/* the blkg and policy id this per-policy data belongs to */
Tejun Heo's avatar
Tejun Heo committed
87
	struct blkcg_gq			*blkg;
Tejun Heo's avatar
Tejun Heo committed
88
	int				plid;
89
90
};

91
/*
92
93
94
95
96
 * Policies that need to keep per-blkcg data which is independent from any
 * request_queue associated to it should implement cpd_alloc/free_fn()
 * methods.  A policy can allocate private data area by allocating larger
 * data structure which embeds blkcg_policy_data at the beginning.
 * cpd_init() is invoked to let each policy handle per-blkcg data.
97
98
 */
struct blkcg_policy_data {
99
100
	/* the blkcg and policy id this per-policy data belongs to */
	struct blkcg			*blkcg;
101
102
103
	int				plid;
};

Tejun Heo's avatar
Tejun Heo committed
104
105
/* association between a blk cgroup and a request queue */
struct blkcg_gq {
106
	/* Pointer to the associated request_queue */
107
108
109
	struct request_queue		*q;
	struct list_head		q_node;
	struct hlist_node		blkcg_node;
Tejun Heo's avatar
Tejun Heo committed
110
	struct blkcg			*blkcg;
111

112
113
114
115
116
117
	/*
	 * Each blkg gets congested separately and the congestion state is
	 * propagated to the matching bdi_writeback_congested.
	 */
	struct bdi_writeback_congested	*wb_congested;

118
119
120
	/* all non-root blkcg_gq's are guaranteed to have access to parent */
	struct blkcg_gq			*parent;

121
122
	/* request allocation list for this blkcg-q pair */
	struct request_list		rl;
123

Tejun Heo's avatar
Tejun Heo committed
124
	/* reference count */
125
	atomic_t			refcnt;
126

127
128
129
	/* is this blkg online? protected by both blkcg and q locks */
	bool				online;

130
131
132
	struct blkg_rwstat		stat_bytes;
	struct blkg_rwstat		stat_ios;

133
	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];
Tejun Heo's avatar
Tejun Heo committed
134

135
	struct rcu_head			rcu_head;
136
137
};

138
typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
139
typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
140
typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
141
typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
142
143
144
typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
145
typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
146
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
147

Tejun Heo's avatar
Tejun Heo committed
148
struct blkcg_policy {
149
150
	int				plid;
	/* cgroup files for the policy */
151
	struct cftype			*legacy_cftypes;
152
153

	/* operations */
154
	blkcg_pol_alloc_cpd_fn		*cpd_alloc_fn;
155
	blkcg_pol_init_cpd_fn		*cpd_init_fn;
156
157
	blkcg_pol_free_cpd_fn		*cpd_free_fn;

158
	blkcg_pol_alloc_pd_fn		*pd_alloc_fn;
159
	blkcg_pol_init_pd_fn		*pd_init_fn;
160
161
	blkcg_pol_online_pd_fn		*pd_online_fn;
	blkcg_pol_offline_pd_fn		*pd_offline_fn;
162
	blkcg_pol_free_pd_fn		*pd_free_fn;
163
	blkcg_pol_reset_pd_stats_fn	*pd_reset_stats_fn;
164
165
};

Tejun Heo's avatar
Tejun Heo committed
166
extern struct blkcg blkcg_root;
Tejun Heo's avatar
Tejun Heo committed
167
extern struct cgroup_subsys_state * const blkcg_root_css;
168

Tejun Heo's avatar
Tejun Heo committed
169
170
struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
				      struct request_queue *q, bool update_hint);
Tejun Heo's avatar
Tejun Heo committed
171
172
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
				    struct request_queue *q);
173
174
175
int blkcg_init_queue(struct request_queue *q);
void blkcg_drain_queue(struct request_queue *q);
void blkcg_exit_queue(struct request_queue *q);
176

177
/* Blkio controller policy registration */
178
int blkcg_policy_register(struct blkcg_policy *pol);
Tejun Heo's avatar
Tejun Heo committed
179
void blkcg_policy_unregister(struct blkcg_policy *pol);
180
int blkcg_activate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
181
			  const struct blkcg_policy *pol);
182
void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
183
			     const struct blkcg_policy *pol);
184

185
const char *blkg_dev_name(struct blkcg_gq *blkg);
Tejun Heo's avatar
Tejun Heo committed
186
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
187
188
		       u64 (*prfill)(struct seq_file *,
				     struct blkg_policy_data *, int),
Tejun Heo's avatar
Tejun Heo committed
189
		       const struct blkcg_policy *pol, int data,
190
		       bool show_total);
191
192
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
193
			 const struct blkg_rwstat *rwstat);
194
195
196
u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
		       int off);
197
198
199
200
int blkg_print_stat_bytes(struct seq_file *sf, void *v);
int blkg_print_stat_ios(struct seq_file *sf, void *v);
int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);
int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v);
201

202
203
204
205
u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
			    struct blkcg_policy *pol, int off);
struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
					     struct blkcg_policy *pol, int off);
206

207
struct blkg_conf_ctx {
208
	struct gendisk			*disk;
Tejun Heo's avatar
Tejun Heo committed
209
	struct blkcg_gq			*blkg;
210
	char				*body;
211
212
};

Tejun Heo's avatar
Tejun Heo committed
213
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
214
		   char *input, struct blkg_conf_ctx *ctx);
215
216
217
void blkg_conf_finish(struct blkg_conf_ctx *ctx);


218
219
220
221
222
static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
{
	return css ? container_of(css, struct blkcg, css) : NULL;
}

223
224
static inline struct blkcg *task_blkcg(struct task_struct *tsk)
{
225
	return css_to_blkcg(task_css(tsk, io_cgrp_id));
226
227
228
229
230
}

static inline struct blkcg *bio_blkcg(struct bio *bio)
{
	if (bio && bio->bi_css)
231
		return css_to_blkcg(bio->bi_css);
232
233
234
	return task_blkcg(current);
}

235
236
237
static inline struct cgroup_subsys_state *
task_get_blkcg_css(struct task_struct *task)
{
238
	return task_get_css(task, io_cgrp_id);
239
240
}

241
242
243
244
245
246
247
248
/**
 * blkcg_parent - get the parent of a blkcg
 * @blkcg: blkcg of interest
 *
 * Return the parent blkcg of @blkcg.  Can be called anytime.
 */
static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
{
Tejun Heo's avatar
Tejun Heo committed
249
	return css_to_blkcg(blkcg->css.parent);
250
251
}

Tejun Heo's avatar
Tejun Heo committed
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
/**
 * __blkg_lookup - internal version of blkg_lookup()
 * @blkcg: blkcg of interest
 * @q: request_queue of interest
 * @update_hint: whether to update lookup hint with the result or not
 *
 * This is internal version and shouldn't be used by policy
 * implementations.  Looks up blkgs for the @blkcg - @q pair regardless of
 * @q's bypass state.  If @update_hint is %true, the caller should be
 * holding @q->queue_lock and lookup hint is updated on success.
 */
static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
					     struct request_queue *q,
					     bool update_hint)
{
	struct blkcg_gq *blkg;

269
270
271
	if (blkcg == &blkcg_root)
		return q->root_blkg;

Tejun Heo's avatar
Tejun Heo committed
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
	blkg = rcu_dereference(blkcg->blkg_hint);
	if (blkg && blkg->q == q)
		return blkg;

	return blkg_lookup_slowpath(blkcg, q, update_hint);
}

/**
 * blkg_lookup - lookup blkg for the specified blkcg - q pair
 * @blkcg: blkcg of interest
 * @q: request_queue of interest
 *
 * Lookup blkg for the @blkcg - @q pair.  This function should be called
 * under RCU read lock and is guaranteed to return %NULL if @q is bypassing
 * - see blk_queue_bypass_start() for details.
 */
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
					   struct request_queue *q)
{
	WARN_ON_ONCE(!rcu_read_lock_held());

	if (unlikely(blk_queue_bypass(q)))
		return NULL;
	return __blkg_lookup(blkcg, q, false);
}

298
299
300
301
302
303
304
/**
 * blkg_to_pdata - get policy private data
 * @blkg: blkg of interest
 * @pol: policy of interest
 *
 * Return pointer to private data associated with the @blkg-@pol pair.
 */
305
306
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
						  struct blkcg_policy *pol)
307
{
308
	return blkg ? blkg->pd[pol->plid] : NULL;
309
310
}

311
312
313
static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
						     struct blkcg_policy *pol)
{
314
	return blkcg ? blkcg->cpd[pol->plid] : NULL;
315
316
}

317
318
/**
 * pdata_to_blkg - get blkg associated with policy private data
319
 * @pd: policy private data of interest
320
 *
321
 * @pd is policy private data.  Determine the blkg it's associated with.
322
 */
323
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
324
{
325
	return pd ? pd->blkg : NULL;
326
327
}

328
329
330
331
332
static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
{
	return cpd ? cpd->blkcg : NULL;
}

Tejun Heo's avatar
Tejun Heo committed
333
334
335
336
337
338
339
340
/**
 * blkg_path - format cgroup path of blkg
 * @blkg: blkg of interest
 * @buf: target buffer
 * @buflen: target buffer length
 *
 * Format the path of the cgroup of @blkg into @buf.
 */
Tejun Heo's avatar
Tejun Heo committed
341
static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
342
{
Tejun Heo's avatar
Tejun Heo committed
343
	char *p;
Tejun Heo's avatar
Tejun Heo committed
344

Tejun Heo's avatar
Tejun Heo committed
345
346
	p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
	if (!p) {
Tejun Heo's avatar
Tejun Heo committed
347
		strncpy(buf, "<unavailable>", buflen);
Tejun Heo's avatar
Tejun Heo committed
348
349
350
351
352
		return -ENAMETOOLONG;
	}

	memmove(buf, p, buf + buflen - p);
	return 0;
353
354
}

Tejun Heo's avatar
Tejun Heo committed
355
356
357
358
/**
 * blkg_get - get a blkg reference
 * @blkg: blkg to get
 *
359
 * The caller should be holding an existing reference.
Tejun Heo's avatar
Tejun Heo committed
360
 */
Tejun Heo's avatar
Tejun Heo committed
361
static inline void blkg_get(struct blkcg_gq *blkg)
Tejun Heo's avatar
Tejun Heo committed
362
{
363
364
	WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
	atomic_inc(&blkg->refcnt);
Tejun Heo's avatar
Tejun Heo committed
365
366
}

367
void __blkg_release_rcu(struct rcu_head *rcu);
Tejun Heo's avatar
Tejun Heo committed
368
369
370
371
372

/**
 * blkg_put - put a blkg reference
 * @blkg: blkg to put
 */
Tejun Heo's avatar
Tejun Heo committed
373
static inline void blkg_put(struct blkcg_gq *blkg)
Tejun Heo's avatar
Tejun Heo committed
374
{
375
376
	WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
	if (atomic_dec_and_test(&blkg->refcnt))
377
		call_rcu(&blkg->rcu_head, __blkg_release_rcu);
Tejun Heo's avatar
Tejun Heo committed
378
379
}

380
381
382
/**
 * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
 * @d_blkg: loop cursor pointing to the current descendant
383
 * @pos_css: used for iteration
384
385
386
387
388
 * @p_blkg: target blkg to walk descendants of
 *
 * Walk @c_blkg through the descendants of @p_blkg.  Must be used with RCU
 * read locked.  If called under either blkcg or queue lock, the iteration
 * is guaranteed to include all and only online blkgs.  The caller may
389
 * update @pos_css by calling css_rightmost_descendant() to skip subtree.
390
 * @p_blkg is included in the iteration and the first node to be visited.
391
 */
392
393
394
#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg)		\
	css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css)	\
		if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css),	\
395
396
					      (p_blkg)->q, false)))

397
398
399
/**
 * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
 * @d_blkg: loop cursor pointing to the current descendant
400
 * @pos_css: used for iteration
401
402
403
 * @p_blkg: target blkg to walk descendants of
 *
 * Similar to blkg_for_each_descendant_pre() but performs post-order
404
405
 * traversal instead.  Synchronization rules are the same.  @p_blkg is
 * included in the iteration and the last node to be visited.
406
 */
407
408
409
#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg)		\
	css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css)	\
		if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css),	\
410
411
					      (p_blkg)->q, false)))

412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
/**
 * blk_get_rl - get request_list to use
 * @q: request_queue of interest
 * @bio: bio which will be attached to the allocated request (may be %NULL)
 *
 * The caller wants to allocate a request from @q to use for @bio.  Find
 * the request_list to use and obtain a reference on it.  Should be called
 * under queue_lock.  This function is guaranteed to return non-%NULL
 * request_list.
 */
static inline struct request_list *blk_get_rl(struct request_queue *q,
					      struct bio *bio)
{
	struct blkcg *blkcg;
	struct blkcg_gq *blkg;

	rcu_read_lock();

	blkcg = bio_blkcg(bio);

	/* bypass blkg lookup and use @q->root_rl directly for root */
	if (blkcg == &blkcg_root)
		goto root_rl;

	/*
	 * Try to use blkg->rl.  blkg lookup may fail under memory pressure
	 * or if either the blkcg or queue is going away.  Fall back to
	 * root_rl in such cases.
	 */
441
442
	blkg = blkg_lookup(blkcg, q);
	if (unlikely(!blkg))
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
		goto root_rl;

	blkg_get(blkg);
	rcu_read_unlock();
	return &blkg->rl;
root_rl:
	rcu_read_unlock();
	return &q->root_rl;
}

/**
 * blk_put_rl - put request_list
 * @rl: request_list to put
 *
 * Put the reference acquired by blk_get_rl().  Should be called under
 * queue_lock.
 */
static inline void blk_put_rl(struct request_list *rl)
{
462
	if (rl->blkg->blkcg != &blkcg_root)
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
		blkg_put(rl->blkg);
}

/**
 * blk_rq_set_rl - associate a request with a request_list
 * @rq: request of interest
 * @rl: target request_list
 *
 * Associate @rq with @rl so that accounting and freeing can know the
 * request_list @rq came from.
 */
static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
{
	rq->rl = rl;
}

/**
 * blk_rq_rl - return the request_list a request came from
 * @rq: request of interest
 *
 * Return the request_list @rq is allocated from.
 */
static inline struct request_list *blk_rq_rl(struct request *rq)
{
	return rq->rl;
}

struct request_list *__blk_queue_next_rl(struct request_list *rl,
					 struct request_queue *q);
/**
 * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
 *
 * Should be used under queue_lock.
 */
#define blk_queue_for_each_rl(rl, q)	\
	for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))

Tejun Heo's avatar
Tejun Heo committed
500
static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
501
{
Tejun Heo's avatar
Tejun Heo committed
502
503
504
505
506
507
	int ret;

	ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
	if (ret)
		return ret;

508
	atomic64_set(&stat->aux_cnt, 0);
Tejun Heo's avatar
Tejun Heo committed
509
510
511
512
513
514
	return 0;
}

static inline void blkg_stat_exit(struct blkg_stat *stat)
{
	percpu_counter_destroy(&stat->cpu_cnt);
515
516
}

517
518
519
520
521
/**
 * blkg_stat_add - add a value to a blkg_stat
 * @stat: target blkg_stat
 * @val: value to add
 *
Tejun Heo's avatar
Tejun Heo committed
522
523
 * Add @val to @stat.  The caller must ensure that IRQ on the same CPU
 * don't re-enter this function for the same counter.
524
525
526
 */
static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
{
Tejun Heo's avatar
Tejun Heo committed
527
	__percpu_counter_add(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
528
529
530
531
532
533
534
535
}

/**
 * blkg_stat_read - read the current value of a blkg_stat
 * @stat: blkg_stat to read
 */
static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
{
Tejun Heo's avatar
Tejun Heo committed
536
	return percpu_counter_sum_positive(&stat->cpu_cnt);
537
538
539
540
541
542
543
544
}

/**
 * blkg_stat_reset - reset a blkg_stat
 * @stat: blkg_stat to reset
 */
static inline void blkg_stat_reset(struct blkg_stat *stat)
{
Tejun Heo's avatar
Tejun Heo committed
545
	percpu_counter_set(&stat->cpu_cnt, 0);
546
	atomic64_set(&stat->aux_cnt, 0);
547
548
}

549
/**
550
 * blkg_stat_add_aux - add a blkg_stat into another's aux count
551
552
553
 * @to: the destination blkg_stat
 * @from: the source
 *
554
 * Add @from's count including the aux one to @to's aux count.
555
 */
556
557
static inline void blkg_stat_add_aux(struct blkg_stat *to,
				     struct blkg_stat *from)
558
{
559
560
	atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
		     &to->aux_cnt);
561
562
}

Tejun Heo's avatar
Tejun Heo committed
563
static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
564
{
Tejun Heo's avatar
Tejun Heo committed
565
566
567
568
569
570
571
572
573
574
575
576
577
	int i, ret;

	for (i = 0; i < BLKG_RWSTAT_NR; i++) {
		ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp);
		if (ret) {
			while (--i >= 0)
				percpu_counter_destroy(&rwstat->cpu_cnt[i]);
			return ret;
		}
		atomic64_set(&rwstat->aux_cnt[i], 0);
	}
	return 0;
}
578

Tejun Heo's avatar
Tejun Heo committed
579
580
581
static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
{
	int i;
582
583

	for (i = 0; i < BLKG_RWSTAT_NR; i++)
Tejun Heo's avatar
Tejun Heo committed
584
		percpu_counter_destroy(&rwstat->cpu_cnt[i]);
585
586
}

587
588
589
590
591
592
593
594
595
596
597
598
/**
 * blkg_rwstat_add - add a value to a blkg_rwstat
 * @rwstat: target blkg_rwstat
 * @rw: mask of REQ_{WRITE|SYNC}
 * @val: value to add
 *
 * Add @val to @rwstat.  The counters are chosen according to @rw.  The
 * caller is responsible for synchronizing calls to this function.
 */
static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
				   int rw, uint64_t val)
{
Tejun Heo's avatar
Tejun Heo committed
599
	struct percpu_counter *cnt;
600
601

	if (rw & REQ_WRITE)
Tejun Heo's avatar
Tejun Heo committed
602
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
603
	else
Tejun Heo's avatar
Tejun Heo committed
604
605
606
607
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];

	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);

608
	if (rw & REQ_SYNC)
Tejun Heo's avatar
Tejun Heo committed
609
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
610
	else
Tejun Heo's avatar
Tejun Heo committed
611
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
612

Tejun Heo's avatar
Tejun Heo committed
613
	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
614
615
616
617
618
619
}

/**
 * blkg_rwstat_read - read the current values of a blkg_rwstat
 * @rwstat: blkg_rwstat to read
 *
Tejun Heo's avatar
Tejun Heo committed
620
 * Read the current snapshot of @rwstat and return it in the aux counts.
621
 */
622
static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
623
{
Tejun Heo's avatar
Tejun Heo committed
624
625
	struct blkg_rwstat result;
	int i;
626

Tejun Heo's avatar
Tejun Heo committed
627
628
629
630
	for (i = 0; i < BLKG_RWSTAT_NR; i++)
		atomic64_set(&result.aux_cnt[i],
			     percpu_counter_sum_positive(&rwstat->cpu_cnt[i]));
	return result;
631
632
633
}

/**
634
 * blkg_rwstat_total - read the total count of a blkg_rwstat
635
636
637
638
639
640
 * @rwstat: blkg_rwstat to read
 *
 * Return the total count of @rwstat regardless of the IO direction.  This
 * function can be called without synchronization and takes care of u64
 * atomicity.
 */
641
static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
642
643
644
{
	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);

Tejun Heo's avatar
Tejun Heo committed
645
646
	return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
		atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
647
648
649
650
651
652
653
654
}

/**
 * blkg_rwstat_reset - reset a blkg_rwstat
 * @rwstat: blkg_rwstat to reset
 */
static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
{
655
656
	int i;

Tejun Heo's avatar
Tejun Heo committed
657
658
	for (i = 0; i < BLKG_RWSTAT_NR; i++) {
		percpu_counter_set(&rwstat->cpu_cnt[i], 0);
659
		atomic64_set(&rwstat->aux_cnt[i], 0);
Tejun Heo's avatar
Tejun Heo committed
660
	}
661
662
}

663
/**
664
 * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
665
666
667
 * @to: the destination blkg_rwstat
 * @from: the source
 *
668
 * Add @from's count including the aux one to @to's aux count.
669
 */
670
671
static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
				       struct blkg_rwstat *from)
672
673
674
675
676
{
	struct blkg_rwstat v = blkg_rwstat_read(from);
	int i;

	for (i = 0; i < BLKG_RWSTAT_NR; i++)
Tejun Heo's avatar
Tejun Heo committed
677
678
		atomic64_add(atomic64_read(&v.aux_cnt[i]) +
			     atomic64_read(&from->aux_cnt[i]),
679
			     &to->aux_cnt[i]);
680
681
}

682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
#ifdef CONFIG_BLK_DEV_THROTTLING
extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
			   struct bio *bio);
#else
static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
				  struct bio *bio) { return false; }
#endif

static inline bool blkcg_bio_issue_check(struct request_queue *q,
					 struct bio *bio)
{
	struct blkcg *blkcg;
	struct blkcg_gq *blkg;
	bool throtl = false;

	rcu_read_lock();
	blkcg = bio_blkcg(bio);

	blkg = blkg_lookup(blkcg, q);
	if (unlikely(!blkg)) {
		spin_lock_irq(q->queue_lock);
		blkg = blkg_lookup_create(blkcg, q);
		if (IS_ERR(blkg))
			blkg = NULL;
		spin_unlock_irq(q->queue_lock);
	}

	throtl = blk_throtl_bio(q, blkg, bio);

711
712
713
714
715
716
717
	if (!throtl) {
		blkg = blkg ?: q->root_blkg;
		blkg_rwstat_add(&blkg->stat_bytes, bio->bi_flags,
				bio->bi_iter.bi_size);
		blkg_rwstat_add(&blkg->stat_ios, bio->bi_flags, 1);
	}

718
719
720
721
	rcu_read_unlock();
	return !throtl;
}

722
723
#else	/* CONFIG_BLK_CGROUP */

724
725
struct blkcg {
};
726

727
728
729
struct blkg_policy_data {
};

730
731
732
struct blkcg_policy_data {
};

Tejun Heo's avatar
Tejun Heo committed
733
struct blkcg_gq {
734
735
};

Tejun Heo's avatar
Tejun Heo committed
736
struct blkcg_policy {
737
738
};

Tejun Heo's avatar
Tejun Heo committed
739
740
#define blkcg_root_css	((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))

741
742
743
744
745
746
static inline struct cgroup_subsys_state *
task_get_blkcg_css(struct task_struct *task)
{
	return NULL;
}

747
748
#ifdef CONFIG_BLOCK

Tejun Heo's avatar
Tejun Heo committed
749
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
750
751
752
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
static inline void blkcg_drain_queue(struct request_queue *q) { }
static inline void blkcg_exit_queue(struct request_queue *q) { }
753
static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
Tejun Heo's avatar
Tejun Heo committed
754
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
755
static inline int blkcg_activate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
756
					const struct blkcg_policy *pol) { return 0; }
757
static inline void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
758
759
					   const struct blkcg_policy *pol) { }

760
static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
761

762
763
764
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
						  struct blkcg_policy *pol) { return NULL; }
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
Tejun Heo's avatar
Tejun Heo committed
765
766
767
static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
static inline void blkg_get(struct blkcg_gq *blkg) { }
static inline void blkg_put(struct blkcg_gq *blkg) { }
768

769
770
771
772
773
774
static inline struct request_list *blk_get_rl(struct request_queue *q,
					      struct bio *bio) { return &q->root_rl; }
static inline void blk_put_rl(struct request_list *rl) { }
static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }

775
776
777
static inline bool blkcg_bio_issue_check(struct request_queue *q,
					 struct bio *bio) { return true; }

778
779
780
#define blk_queue_for_each_rl(rl, q)	\
	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)

781
#endif	/* CONFIG_BLOCK */
782
783
#endif	/* CONFIG_BLK_CGROUP */
#endif	/* _BLK_CGROUP_H */