blk-rq-qos.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef RQ_QOS_H
  3#define RQ_QOS_H
  4
  5#include <linux/kernel.h>
  6#include <linux/blkdev.h>
  7#include <linux/blk_types.h>
  8#include <linux/atomic.h>
  9#include <linux/wait.h>
 10#include <linux/blk-mq.h>
 11
 12#include "blk-mq-debugfs.h"
 13
 14struct blk_mq_debugfs_attr;
 15
 16enum rq_qos_id {
 17	RQ_QOS_WBT,
 18	RQ_QOS_LATENCY,
 19	RQ_QOS_COST,
 20};
 21
 22struct rq_wait {
 23	wait_queue_head_t wait;
 24	atomic_t inflight;
 25};
 26
 27struct rq_qos {
 28	const struct rq_qos_ops *ops;
 29	struct gendisk *disk;
 30	enum rq_qos_id id;
 31	struct rq_qos *next;
 32#ifdef CONFIG_BLK_DEBUG_FS
 33	struct dentry *debugfs_dir;
 34#endif
 35};
 36
 37struct rq_qos_ops {
 38	void (*throttle)(struct rq_qos *, struct bio *);
 39	void (*track)(struct rq_qos *, struct request *, struct bio *);
 40	void (*merge)(struct rq_qos *, struct request *, struct bio *);
 41	void (*issue)(struct rq_qos *, struct request *);
 42	void (*requeue)(struct rq_qos *, struct request *);
 43	void (*done)(struct rq_qos *, struct request *);
 44	void (*done_bio)(struct rq_qos *, struct bio *);
 45	void (*cleanup)(struct rq_qos *, struct bio *);
 46	void (*queue_depth_changed)(struct rq_qos *);
 47	void (*exit)(struct rq_qos *);
 48	const struct blk_mq_debugfs_attr *debugfs_attrs;
 49};
 50
 51struct rq_depth {
 52	unsigned int max_depth;
 53
 54	int scale_step;
 55	bool scaled_max;
 56
 57	unsigned int queue_depth;
 58	unsigned int default_depth;
 59};
 60
 61static inline struct rq_qos *rq_qos_id(struct request_queue *q,
 62				       enum rq_qos_id id)
 63{
 64	struct rq_qos *rqos;
 65	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
 66		if (rqos->id == id)
 67			break;
 68	}
 69	return rqos;
 70}
 71
 72static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
 73{
 74	return rq_qos_id(q, RQ_QOS_WBT);
 75}
 76
 77static inline struct rq_qos *iolat_rq_qos(struct request_queue *q)
 78{
 79	return rq_qos_id(q, RQ_QOS_LATENCY);
 80}
 81
 82static inline void rq_wait_init(struct rq_wait *rq_wait)
 83{
 84	atomic_set(&rq_wait->inflight, 0);
 85	init_waitqueue_head(&rq_wait->wait);
 86}
 87
 88int rq_qos_add(struct rq_qos *rqos, struct gendisk *disk, enum rq_qos_id id,
 89		const struct rq_qos_ops *ops);
 90void rq_qos_del(struct rq_qos *rqos);
 91
 92typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
 93typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
 94
 95void rq_qos_wait(struct rq_wait *rqw, void *private_data,
 96		 acquire_inflight_cb_t *acquire_inflight_cb,
 97		 cleanup_cb_t *cleanup_cb);
 98bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
 99bool rq_depth_scale_up(struct rq_depth *rqd);
100bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
101bool rq_depth_calc_max_depth(struct rq_depth *rqd);
102
103void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
104void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
105void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
106void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
107void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
108void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
109void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
110void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
111void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
112
113static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
114{
115	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
116		__rq_qos_cleanup(q->rq_qos, bio);
117}
118
119static inline void rq_qos_done(struct request_queue *q, struct request *rq)
120{
121	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) &&
122	    q->rq_qos && !blk_rq_is_passthrough(rq))
123		__rq_qos_done(q->rq_qos, rq);
124}
125
126static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
127{
128	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
129		__rq_qos_issue(q->rq_qos, rq);
130}
131
132static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
133{
134	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
135		__rq_qos_requeue(q->rq_qos, rq);
136}
137
138static inline void rq_qos_done_bio(struct bio *bio)
139{
140	struct request_queue *q;
141
142	if (!bio->bi_bdev || (!bio_flagged(bio, BIO_QOS_THROTTLED) &&
143			     !bio_flagged(bio, BIO_QOS_MERGED)))
144		return;
145
146	q = bdev_get_queue(bio->bi_bdev);
147
148	/*
149	 * A BIO may carry BIO_QOS_* flags even if the associated request_queue
150	 * does not have rq_qos enabled. This can happen with stacked block
151	 * devices — for example, NVMe multipath, where it's possible that the
152	 * bottom device has QoS enabled but the top device does not. Therefore,
153	 * always verify that q->rq_qos is present and QoS is enabled before
154	 * calling __rq_qos_done_bio().
155	 */
156	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
157		__rq_qos_done_bio(q->rq_qos, bio);
158}
159
160static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
161{
162	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos) {
163		bio_set_flag(bio, BIO_QOS_THROTTLED);
164		__rq_qos_throttle(q->rq_qos, bio);
165	}
166}
167
168static inline void rq_qos_track(struct request_queue *q, struct request *rq,
169				struct bio *bio)
170{
171	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
172		__rq_qos_track(q->rq_qos, rq, bio);
173}
174
175static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
176				struct bio *bio)
177{
178	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos) {
179		bio_set_flag(bio, BIO_QOS_MERGED);
180		__rq_qos_merge(q->rq_qos, rq, bio);
181	}
182}
183
184static inline void rq_qos_queue_depth_changed(struct request_queue *q)
185{
186	if (test_bit(QUEUE_FLAG_QOS_ENABLED, &q->queue_flags) && q->rq_qos)
187		__rq_qos_queue_depth_changed(q->rq_qos);
188}
189
190void rq_qos_exit(struct request_queue *);
191
192#endif