blk-cgroup.h 21.3 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
	struct blkg_policy_data		*pd[BLKCG_MAX_POLS];
Tejun Heo's avatar
Tejun Heo committed
131

132
	struct rcu_head			rcu_head;
133
134
};

135
typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
136
typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
137
typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
138
typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, int node);
139
140
141
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);
142
typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
143
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
144

Tejun Heo's avatar
Tejun Heo committed
145
struct blkcg_policy {
146
147
148
	int				plid;
	/* cgroup files for the policy */
	struct cftype			*cftypes;
149
150

	/* operations */
151
	blkcg_pol_alloc_cpd_fn		*cpd_alloc_fn;
152
	blkcg_pol_init_cpd_fn		*cpd_init_fn;
153
154
	blkcg_pol_free_cpd_fn		*cpd_free_fn;

155
	blkcg_pol_alloc_pd_fn		*pd_alloc_fn;
156
	blkcg_pol_init_pd_fn		*pd_init_fn;
157
158
	blkcg_pol_online_pd_fn		*pd_online_fn;
	blkcg_pol_offline_pd_fn		*pd_offline_fn;
159
	blkcg_pol_free_pd_fn		*pd_free_fn;
160
	blkcg_pol_reset_pd_stats_fn	*pd_reset_stats_fn;
161
162
};

Tejun Heo's avatar
Tejun Heo committed
163
extern struct blkcg blkcg_root;
Tejun Heo's avatar
Tejun Heo committed
164
extern struct cgroup_subsys_state * const blkcg_root_css;
165

Tejun Heo's avatar
Tejun Heo committed
166
167
struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
				      struct request_queue *q, bool update_hint);
Tejun Heo's avatar
Tejun Heo committed
168
169
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
				    struct request_queue *q);
170
171
172
int blkcg_init_queue(struct request_queue *q);
void blkcg_drain_queue(struct request_queue *q);
void blkcg_exit_queue(struct request_queue *q);
173

174
/* Blkio controller policy registration */
175
int blkcg_policy_register(struct blkcg_policy *pol);
Tejun Heo's avatar
Tejun Heo committed
176
void blkcg_policy_unregister(struct blkcg_policy *pol);
177
int blkcg_activate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
178
			  const struct blkcg_policy *pol);
179
void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
180
			     const struct blkcg_policy *pol);
181

Tejun Heo's avatar
Tejun Heo committed
182
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
183
184
		       u64 (*prfill)(struct seq_file *,
				     struct blkg_policy_data *, int),
Tejun Heo's avatar
Tejun Heo committed
185
		       const struct blkcg_policy *pol, int data,
186
		       bool show_total);
187
188
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,
189
			 const struct blkg_rwstat *rwstat);
190
191
192
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);
193

194
195
196
197
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);
198

199
struct blkg_conf_ctx {
200
	struct gendisk			*disk;
Tejun Heo's avatar
Tejun Heo committed
201
	struct blkcg_gq			*blkg;
202
	u64				v;
203
204
};

Tejun Heo's avatar
Tejun Heo committed
205
206
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
		   const char *input, struct blkg_conf_ctx *ctx);
207
208
209
void blkg_conf_finish(struct blkg_conf_ctx *ctx);


210
211
212
213
214
static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
{
	return css ? container_of(css, struct blkcg, css) : NULL;
}

215
216
static inline struct blkcg *task_blkcg(struct task_struct *tsk)
{
217
	return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
218
219
220
221
222
}

static inline struct blkcg *bio_blkcg(struct bio *bio)
{
	if (bio && bio->bi_css)
223
		return css_to_blkcg(bio->bi_css);
224
225
226
	return task_blkcg(current);
}

227
228
229
230
231
232
static inline struct cgroup_subsys_state *
task_get_blkcg_css(struct task_struct *task)
{
	return task_get_css(task, blkio_cgrp_id);
}

233
234
235
236
237
238
239
240
/**
 * 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
241
	return css_to_blkcg(blkcg->css.parent);
242
243
}

Tejun Heo's avatar
Tejun Heo committed
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
/**
 * __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;

261
262
263
	if (blkcg == &blkcg_root)
		return q->root_blkg;

Tejun Heo's avatar
Tejun Heo committed
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
	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);
}

290
291
292
293
294
295
296
/**
 * 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.
 */
297
298
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
						  struct blkcg_policy *pol)
299
{
300
	return blkg ? blkg->pd[pol->plid] : NULL;
301
302
}

303
304
305
static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
						     struct blkcg_policy *pol)
{
306
	return blkcg ? blkcg->cpd[pol->plid] : NULL;
307
308
}

309
310
/**
 * pdata_to_blkg - get blkg associated with policy private data
311
 * @pd: policy private data of interest
312
 *
313
 * @pd is policy private data.  Determine the blkg it's associated with.
314
 */
315
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
316
{
317
	return pd ? pd->blkg : NULL;
318
319
}

320
321
322
323
324
static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
{
	return cpd ? cpd->blkcg : NULL;
}

Tejun Heo's avatar
Tejun Heo committed
325
326
327
328
329
330
331
332
/**
 * 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
333
static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
334
{
Tejun Heo's avatar
Tejun Heo committed
335
	char *p;
Tejun Heo's avatar
Tejun Heo committed
336

Tejun Heo's avatar
Tejun Heo committed
337
338
	p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
	if (!p) {
Tejun Heo's avatar
Tejun Heo committed
339
		strncpy(buf, "<unavailable>", buflen);
Tejun Heo's avatar
Tejun Heo committed
340
341
342
343
344
		return -ENAMETOOLONG;
	}

	memmove(buf, p, buf + buflen - p);
	return 0;
345
346
}

Tejun Heo's avatar
Tejun Heo committed
347
348
349
350
/**
 * blkg_get - get a blkg reference
 * @blkg: blkg to get
 *
351
 * The caller should be holding an existing reference.
Tejun Heo's avatar
Tejun Heo committed
352
 */
Tejun Heo's avatar
Tejun Heo committed
353
static inline void blkg_get(struct blkcg_gq *blkg)
Tejun Heo's avatar
Tejun Heo committed
354
{
355
356
	WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
	atomic_inc(&blkg->refcnt);
Tejun Heo's avatar
Tejun Heo committed
357
358
}

359
void __blkg_release_rcu(struct rcu_head *rcu);
Tejun Heo's avatar
Tejun Heo committed
360
361
362
363
364

/**
 * blkg_put - put a blkg reference
 * @blkg: blkg to put
 */
Tejun Heo's avatar
Tejun Heo committed
365
static inline void blkg_put(struct blkcg_gq *blkg)
Tejun Heo's avatar
Tejun Heo committed
366
{
367
368
	WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
	if (atomic_dec_and_test(&blkg->refcnt))
369
		call_rcu(&blkg->rcu_head, __blkg_release_rcu);
Tejun Heo's avatar
Tejun Heo committed
370
371
}

372
373
374
/**
 * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
 * @d_blkg: loop cursor pointing to the current descendant
375
 * @pos_css: used for iteration
376
377
378
379
380
 * @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
381
 * update @pos_css by calling css_rightmost_descendant() to skip subtree.
382
 * @p_blkg is included in the iteration and the first node to be visited.
383
 */
384
385
386
#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),	\
387
388
					      (p_blkg)->q, false)))

389
390
391
/**
 * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
 * @d_blkg: loop cursor pointing to the current descendant
392
 * @pos_css: used for iteration
393
394
395
 * @p_blkg: target blkg to walk descendants of
 *
 * Similar to blkg_for_each_descendant_pre() but performs post-order
396
397
 * traversal instead.  Synchronization rules are the same.  @p_blkg is
 * included in the iteration and the last node to be visited.
398
 */
399
400
401
#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),	\
402
403
					      (p_blkg)->q, false)))

404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
/**
 * 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.
	 */
433
434
	blkg = blkg_lookup(blkcg, q);
	if (unlikely(!blkg))
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
		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)
{
454
	if (rl->blkg->blkcg != &blkcg_root)
455
456
457
458
459
460
461
462
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
		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
492
static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
493
{
Tejun Heo's avatar
Tejun Heo committed
494
495
496
497
498
499
	int ret;

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

500
	atomic64_set(&stat->aux_cnt, 0);
Tejun Heo's avatar
Tejun Heo committed
501
502
503
504
505
506
	return 0;
}

static inline void blkg_stat_exit(struct blkg_stat *stat)
{
	percpu_counter_destroy(&stat->cpu_cnt);
507
508
}

509
510
511
512
513
/**
 * 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
514
515
 * Add @val to @stat.  The caller must ensure that IRQ on the same CPU
 * don't re-enter this function for the same counter.
516
517
518
 */
static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
{
Tejun Heo's avatar
Tejun Heo committed
519
	__percpu_counter_add(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
520
521
522
523
524
525
526
527
}

/**
 * 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
528
	return percpu_counter_sum_positive(&stat->cpu_cnt);
529
530
531
532
533
534
535
536
}

/**
 * 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
537
	percpu_counter_set(&stat->cpu_cnt, 0);
538
	atomic64_set(&stat->aux_cnt, 0);
539
540
}

541
/**
542
 * blkg_stat_add_aux - add a blkg_stat into another's aux count
543
544
545
 * @to: the destination blkg_stat
 * @from: the source
 *
546
 * Add @from's count including the aux one to @to's aux count.
547
 */
548
549
static inline void blkg_stat_add_aux(struct blkg_stat *to,
				     struct blkg_stat *from)
550
{
551
552
	atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
		     &to->aux_cnt);
553
554
}

Tejun Heo's avatar
Tejun Heo committed
555
static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
556
{
Tejun Heo's avatar
Tejun Heo committed
557
558
559
560
561
562
563
564
565
566
567
568
569
	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;
}
570

Tejun Heo's avatar
Tejun Heo committed
571
572
573
static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat)
{
	int i;
574
575

	for (i = 0; i < BLKG_RWSTAT_NR; i++)
Tejun Heo's avatar
Tejun Heo committed
576
		percpu_counter_destroy(&rwstat->cpu_cnt[i]);
577
578
}

579
580
581
582
583
584
585
586
587
588
589
590
/**
 * 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
591
	struct percpu_counter *cnt;
592
593

	if (rw & REQ_WRITE)
Tejun Heo's avatar
Tejun Heo committed
594
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE];
595
	else
Tejun Heo's avatar
Tejun Heo committed
596
597
598
599
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ];

	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);

600
	if (rw & REQ_SYNC)
Tejun Heo's avatar
Tejun Heo committed
601
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC];
602
	else
Tejun Heo's avatar
Tejun Heo committed
603
		cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC];
604

Tejun Heo's avatar
Tejun Heo committed
605
	__percpu_counter_add(cnt, val, BLKG_STAT_CPU_BATCH);
606
607
608
609
610
611
}

/**
 * blkg_rwstat_read - read the current values of a blkg_rwstat
 * @rwstat: blkg_rwstat to read
 *
Tejun Heo's avatar
Tejun Heo committed
612
 * Read the current snapshot of @rwstat and return it in the aux counts.
613
 */
614
static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
615
{
Tejun Heo's avatar
Tejun Heo committed
616
617
	struct blkg_rwstat result;
	int i;
618

Tejun Heo's avatar
Tejun Heo committed
619
620
621
622
	for (i = 0; i < BLKG_RWSTAT_NR; i++)
		atomic64_set(&result.aux_cnt[i],
			     percpu_counter_sum_positive(&rwstat->cpu_cnt[i]));
	return result;
623
624
625
}

/**
626
 * blkg_rwstat_total - read the total count of a blkg_rwstat
627
628
629
630
631
632
 * @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.
 */
633
static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
634
635
636
{
	struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);

Tejun Heo's avatar
Tejun Heo committed
637
638
	return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
		atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
639
640
641
642
643
644
645
646
}

/**
 * blkg_rwstat_reset - reset a blkg_rwstat
 * @rwstat: blkg_rwstat to reset
 */
static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
{
647
648
	int i;

Tejun Heo's avatar
Tejun Heo committed
649
650
	for (i = 0; i < BLKG_RWSTAT_NR; i++) {
		percpu_counter_set(&rwstat->cpu_cnt[i], 0);
651
		atomic64_set(&rwstat->aux_cnt[i], 0);
Tejun Heo's avatar
Tejun Heo committed
652
	}
653
654
}

655
/**
656
 * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count
657
658
659
 * @to: the destination blkg_rwstat
 * @from: the source
 *
660
 * Add @from's count including the aux one to @to's aux count.
661
 */
662
663
static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to,
				       struct blkg_rwstat *from)
664
665
666
667
668
{
	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
669
670
		atomic64_add(atomic64_read(&v.aux_cnt[i]) +
			     atomic64_read(&from->aux_cnt[i]),
671
			     &to->aux_cnt[i]);
672
673
}

674
675
676
677
678
679
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
#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);

	rcu_read_unlock();
	return !throtl;
}

707
708
#else	/* CONFIG_BLK_CGROUP */

709
710
struct blkcg {
};
711

712
713
714
struct blkg_policy_data {
};

715
716
717
struct blkcg_policy_data {
};

Tejun Heo's avatar
Tejun Heo committed
718
struct blkcg_gq {
719
720
};

Tejun Heo's avatar
Tejun Heo committed
721
struct blkcg_policy {
722
723
};

Tejun Heo's avatar
Tejun Heo committed
724
725
#define blkcg_root_css	((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))

726
727
728
729
730
731
static inline struct cgroup_subsys_state *
task_get_blkcg_css(struct task_struct *task)
{
	return NULL;
}

732
733
#ifdef CONFIG_BLOCK

Tejun Heo's avatar
Tejun Heo committed
734
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
735
736
737
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) { }
738
static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
Tejun Heo's avatar
Tejun Heo committed
739
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
740
static inline int blkcg_activate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
741
					const struct blkcg_policy *pol) { return 0; }
742
static inline void blkcg_deactivate_policy(struct request_queue *q,
Tejun Heo's avatar
Tejun Heo committed
743
744
					   const struct blkcg_policy *pol) { }

745
static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
746

747
748
749
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
750
751
752
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) { }
753

754
755
756
757
758
759
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; }

760
761
762
static inline bool blkcg_bio_issue_check(struct request_queue *q,
					 struct bio *bio) { return true; }

763
764
765
#define blk_queue_for_each_rl(rl, q)	\
	for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)

766
#endif	/* CONFIG_BLOCK */
767
768
#endif	/* CONFIG_BLK_CGROUP */
#endif	/* _BLK_CGROUP_H */