block/blk-wbt.h

   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_disable_default(struct request_queue *);
  92 void wbt_enable_default(struct request_queue *);
  93
  94 u64 wbt_get_min_lat(struct request_queue *q);
  95 void wbt_set_min_lat(struct request_queue *q, u64 val);
  96
  97 void wbt_set_write_cache(struct request_queue *, bool);
  98
  99 u64 wbt_default_latency_nsec(struct request_queue *);
 100
 101 #else
 102
 103 static inline void wbt_track(struct request *rq, enum wbt_flags flags)
 104 {
 105 }
 106 static inline int wbt_init(struct request_queue *q)
 107 {
 108         return -EINVAL;
 109 }
 110 static inline void wbt_disable_default(struct request_queue *q)
 111 {
 112 }
 113 static inline void wbt_enable_default(struct request_queue *q)
 114 {
 115 }
 116 static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
 117 {
 118 }
 119 static inline u64 wbt_get_min_lat(struct request_queue *q)
 120 {
 121         return 0;
 122 }
 123 static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
 124 {
 125 }
 126 static inline u64 wbt_default_latency_nsec(struct request_queue *q)
 127 {
 128         return 0;
 129 }
 130
 131 #endif /* CONFIG_BLK_WBT */
 132
 133 #endif