block/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
  14 struct blk_mq_debugfs_attr;
  15
  16 enum rq_qos_id {
  17         RQ_QOS_WBT,
  18         RQ_QOS_LATENCY,
  19         RQ_QOS_COST,
  20         RQ_QOS_IOPRIO,
  21 };
  22
  23 struct rq_wait {
  24         wait_queue_head_t wait;
  25         atomic_t inflight;
  26 };
  27
  28 struct rq_qos {
  29         struct rq_qos_ops *ops;
  30         struct request_queue *q;
  31         enum rq_qos_id id;
  32         struct rq_qos *next;
  33 #ifdef CONFIG_BLK_DEBUG_FS
  34         struct dentry *debugfs_dir;
  35 #endif
  36 };
  37
  38 struct rq_qos_ops {
  39         void (*throttle)(struct rq_qos *, struct bio *);
  40         void (*track)(struct rq_qos *, struct request *, struct bio *);
  41         void (*merge)(struct rq_qos *, struct request *, struct bio *);
  42         void (*issue)(struct rq_qos *, struct request *);
  43         void (*requeue)(struct rq_qos *, struct request *);
  44         void (*done)(struct rq_qos *, struct request *);
  45         void (*done_bio)(struct rq_qos *, struct bio *);
  46         void (*cleanup)(struct rq_qos *, struct bio *);
  47         void (*queue_depth_changed)(struct rq_qos *);
  48         void (*exit)(struct rq_qos *);
  49         const struct blk_mq_debugfs_attr *debugfs_attrs;
  50 };
  51
  52 struct rq_depth {
  53         unsigned int max_depth;
  54
  55         int scale_step;
  56         bool scaled_max;
  57
  58         unsigned int queue_depth;
  59         unsigned int default_depth;
  60 };
  61
  62 static inline struct rq_qos *rq_qos_id(struct request_queue *q,
  63                                        enum rq_qos_id id)
  64 {
  65         struct rq_qos *rqos;
  66         for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
  67                 if (rqos->id == id)
  68                         break;
  69         }
  70         return rqos;
  71 }
  72
  73 static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
  74 {
  75         return rq_qos_id(q, RQ_QOS_WBT);
  76 }
  77
  78 static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
  79 {
  80         return rq_qos_id(q, RQ_QOS_LATENCY);
  81 }
  82
  83 static inline void rq_wait_init(struct rq_wait *rq_wait)
  84 {
  85         atomic_set(&rq_wait->inflight, 0);
  86         init_waitqueue_head(&rq_wait->wait);
  87 }
  88
  89 static inline int rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
  90 {
  91         /*
  92          * No IO can be in-flight when adding rqos, so freeze queue, which
  93          * is fine since we only support rq_qos for blk-mq queue.
  94          *
  95          * Reuse ->queue_lock for protecting against other concurrent
  96          * rq_qos adding/deleting
  97          */
  98         blk_mq_freeze_queue(q);
  99
 100         spin_lock_irq(&q->queue_lock);
 101         if (rq_qos_id(q, rqos->id))
 102                 goto ebusy;
 103         rqos->next = q->rq_qos;
 104         q->rq_qos = rqos;
 105         spin_unlock_irq(&q->queue_lock);
 106
 107         blk_mq_unfreeze_queue(q);
 108
 109         if (rqos->ops->debugfs_attrs)
 110                 blk_mq_debugfs_register_rqos(rqos);
 111
 112         return 0;
 113 ebusy:
 114         spin_unlock_irq(&q->queue_lock);
 115         blk_mq_unfreeze_queue(q);
 116         return -EBUSY;
 117
 118 }
 119
 120 static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
 121 {
 122         struct rq_qos **cur;
 123
 124         /*
 125          * See comment in rq_qos_add() about freezing queue & using
 126          * ->queue_lock.
 127          */
 128         blk_mq_freeze_queue(q);
 129
 130         spin_lock_irq(&q->queue_lock);
 131         for (cur = &q->rq_qos; *cur; cur = &(*cur)->next) {
 132                 if (*cur == rqos) {
 133                         *cur = rqos->next;
 134                         break;
 135                 }
 136         }
 137         spin_unlock_irq(&q->queue_lock);
 138
 139         blk_mq_unfreeze_queue(q);
 140
 141         blk_mq_debugfs_unregister_rqos(rqos);
 142 }
 143
 144 typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data);
 145 typedef void (cleanup_cb_t)(struct rq_wait *rqw, void *private_data);
 146
 147 void rq_qos_wait(struct rq_wait *rqw, void *private_data,
 148                  acquire_inflight_cb_t *acquire_inflight_cb,
 149                  cleanup_cb_t *cleanup_cb);
 150 bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit);
 151 bool rq_depth_scale_up(struct rq_depth *rqd);
 152 bool rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
 153 bool rq_depth_calc_max_depth(struct rq_depth *rqd);
 154
 155 void __rq_qos_cleanup(struct rq_qos *rqos, struct bio *bio);
 156 void __rq_qos_done(struct rq_qos *rqos, struct request *rq);
 157 void __rq_qos_issue(struct rq_qos *rqos, struct request *rq);
 158 void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
 159 void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
 160 void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 161 void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 162 void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
 163 void __rq_qos_queue_depth_changed(struct rq_qos *rqos);
 164
 165 static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
 166 {
 167         if (q->rq_qos)
 168                 __rq_qos_cleanup(q->rq_qos, bio);
 169 }
 170
 171 static inline void rq_qos_done(struct request_queue *q, struct request *rq)
 172 {
 173         if (q->rq_qos)
 174                 __rq_qos_done(q->rq_qos, rq);
 175 }
 176
 177 static inline void rq_qos_issue(struct request_queue *q, struct request *rq)
 178 {
 179         if (q->rq_qos)
 180                 __rq_qos_issue(q->rq_qos, rq);
 181 }
 182
 183 static inline void rq_qos_requeue(struct request_queue *q, struct request *rq)
 184 {
 185         if (q->rq_qos)
 186                 __rq_qos_requeue(q->rq_qos, rq);
 187 }
 188
 189 static inline void rq_qos_done_bio(struct bio *bio)
 190 {
 191         if (bio->bi_bdev && (bio_flagged(bio, BIO_QOS_THROTTLED) ||
 192                              bio_flagged(bio, BIO_QOS_MERGED))) {
 193                 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 194                 if (q->rq_qos)
 195                         __rq_qos_done_bio(q->rq_qos, bio);
 196         }
 197 }
 198
 199 static inline void rq_qos_throttle(struct request_queue *q, struct bio *bio)
 200 {
 201         if (q->rq_qos) {
 202                 bio_set_flag(bio, BIO_QOS_THROTTLED);
 203                 __rq_qos_throttle(q->rq_qos, bio);
 204         }
 205 }
 206
 207 static inline void rq_qos_track(struct request_queue *q, struct request *rq,
 208                                 struct bio *bio)
 209 {
 210         if (q->rq_qos)
 211                 __rq_qos_track(q->rq_qos, rq, bio);
 212 }
 213
 214 static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
 215                                 struct bio *bio)
 216 {
 217         if (q->rq_qos) {
 218                 bio_set_flag(bio, BIO_QOS_MERGED);
 219                 __rq_qos_merge(q->rq_qos, rq, bio);
 220         }
 221 }
 222
 223 static inline void rq_qos_queue_depth_changed(struct request_queue *q)
 224 {
 225         if (q->rq_qos)
 226                 __rq_qos_queue_depth_changed(q->rq_qos);
 227 }
 228
 229 void rq_qos_exit(struct request_queue *);
 230
 231 #endif