Line data    Source code

       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           9 : static inline void wbt_enable_default(struct request_queue *q)
     114             : {
     115           9 : }
     116           1 : static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
     117             : {
     118           1 : }
     119           0 : static inline u64 wbt_get_min_lat(struct request_queue *q)
     120             : {
     121           0 :         return 0;
     122             : }
     123           0 : static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
     124             : {
     125           0 : }
     126           0 : static inline u64 wbt_default_latency_nsec(struct request_queue *q)
     127             : {
     128           0 :         return 0;
     129             : }
     130             : 
     131             : #endif /* CONFIG_BLK_WBT */
     132             : 
     133             : #endif