root/block/blk-wbt.h

INCLUDED FROM

DEFINITIONS

1. RQWB
2. wbt_inflight
3. wbt_track
4. wbt_init
5. wbt_update_limits
6. wbt_disable_default
7. wbt_enable_default
8. wbt_set_write_cache
9. wbt_get_min_lat
10. wbt_set_min_lat
11. wbt_default_latency_nsec

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef WB_THROTTLE_H
   3 #define WB_THROTTLE_H
   4 
   5 #include <linux/kernel.h>
   6 #include <linux/atomic.h>
   7 #include <linux/wait.h>
   8 #include <linux/timer.h>
   9 #include <linux/ktime.h>
  10 
  11 #include "blk-stat.h"
  12 #include "blk-rq-qos.h"
  13 
  14 enum wbt_flags {
  15         WBT_TRACKED             = 1,    /* write, tracked for throttling */
  16         WBT_READ                = 2,    /* read */
  17         WBT_KSWAPD              = 4,    /* write, from kswapd */
  18         WBT_DISCARD             = 8,    /* discard */
  19 
  20         WBT_NR_BITS             = 4,    /* number of bits */
  21 };
  22 
  23 enum {
  24         WBT_RWQ_BG              = 0,
  25         WBT_RWQ_KSWAPD,
  26         WBT_RWQ_DISCARD,
  27         WBT_NUM_RWQ,
  28 };
  29 
  30 /*
  31  * Enable states. Either off, or on by default (done at init time),
  32  * or on through manual setup in sysfs.
  33  */
  34 enum {
  35         WBT_STATE_ON_DEFAULT    = 1,
  36         WBT_STATE_ON_MANUAL     = 2,
  37 };
  38 
  39 struct rq_wb {
  40         /*
  41          * Settings that govern how we throttle
  42          */
  43         unsigned int wb_background;             /* background writeback */
  44         unsigned int wb_normal;                 /* normal writeback */
  45 
  46         short enable_state;                     /* WBT_STATE_* */
  47 
  48         /*
  49          * Number of consecutive periods where we don't have enough
  50          * information to make a firm scale up/down decision.
  51          */
  52         unsigned int unknown_cnt;
  53 
  54         u64 win_nsec;                           /* default window size */
  55         u64 cur_win_nsec;                       /* current window size */
  56 
  57         struct blk_stat_callback *cb;
  58 
  59         u64 sync_issue;
  60         void *sync_cookie;
  61 
  62         unsigned int wc;
  63 
  64         unsigned long last_issue;               /* last non-throttled issue */
  65         unsigned long last_comp;                /* last non-throttled comp */
  66         unsigned long min_lat_nsec;
  67         struct rq_qos rqos;
  68         struct rq_wait rq_wait[WBT_NUM_RWQ];
  69         struct rq_depth rq_depth;
  70 };
  71 
  72 static inline struct rq_wb *RQWB(struct rq_qos *rqos)
  73 {
  74         return container_of(rqos, struct rq_wb, rqos);
  75 }
  76 
  77 static inline unsigned int wbt_inflight(struct rq_wb *rwb)
  78 {
  79         unsigned int i, ret = 0;
  80 
  81         for (i = 0; i < WBT_NUM_RWQ; i++)
  82                 ret += atomic_read(&rwb->rq_wait[i].inflight);
  83 
  84         return ret;
  85 }
  86 
  87 
  88 #ifdef CONFIG_BLK_WBT
  89 
  90 int wbt_init(struct request_queue *);
  91 void wbt_update_limits(struct request_queue *);
  92 void wbt_disable_default(struct request_queue *);
  93 void wbt_enable_default(struct request_queue *);
  94 
  95 u64 wbt_get_min_lat(struct request_queue *q);
  96 void wbt_set_min_lat(struct request_queue *q, u64 val);
  97 
  98 void wbt_set_write_cache(struct request_queue *, bool);
  99 
 100 u64 wbt_default_latency_nsec(struct request_queue *);
 101 
 102 #else
 103 
 104 static inline void wbt_track(struct request *rq, enum wbt_flags flags)
 105 {
 106 }
 107 static inline int wbt_init(struct request_queue *q)
 108 {
 109         return -EINVAL;
 110 }
 111 static inline void wbt_update_limits(struct request_queue *q)
 112 {
 113 }
 114 static inline void wbt_disable_default(struct request_queue *q)
 115 {
 116 }
 117 static inline void wbt_enable_default(struct request_queue *q)
 118 {
 119 }
 120 static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
 121 {
 122 }
 123 static inline u64 wbt_get_min_lat(struct request_queue *q)
 124 {
 125         return 0;
 126 }
 127 static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
 128 {
 129 }
 130 static inline u64 wbt_default_latency_nsec(struct request_queue *q)
 131 {
 132         return 0;
 133 }
 134 
 135 #endif /* CONFIG_BLK_WBT */
 136 
 137 #endif