LXR linux/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
  14enum 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
  23enum {
  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 */
  34enum {
  35        WBT_STATE_ON_DEFAULT    = 1,
  36        WBT_STATE_ON_MANUAL     = 2,
  37};
  38
  39struct 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
  72static inline struct rq_wb *RQWB(struct rq_qos *rqos)
  73{
  74        return container_of(rqos, struct rq_wb, rqos);
  75}
  76
  77static 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
  90int wbt_init(struct request_queue *);
  91void wbt_update_limits(struct request_queue *);
  92void wbt_disable_default(struct request_queue *);
  93void wbt_enable_default(struct request_queue *);
  94
  95u64 wbt_get_min_lat(struct request_queue *q);
  96void wbt_set_min_lat(struct request_queue *q, u64 val);
  97
  98void wbt_set_write_cache(struct request_queue *, bool);
  99
 100u64 wbt_default_latency_nsec(struct request_queue *);
 101
 102#else
 103
 104static inline void wbt_track(struct request *rq, enum wbt_flags flags)
 105{
 106}
 107static inline int wbt_init(struct request_queue *q)
 108{
 109        return -EINVAL;
 110}
 111static inline void wbt_update_limits(struct request_queue *q)
 112{
 113}
 114static inline void wbt_disable_default(struct request_queue *q)
 115{
 116}
 117static inline void wbt_enable_default(struct request_queue *q)
 118{
 119}
 120static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
 121{
 122}
 123static inline u64 wbt_get_min_lat(struct request_queue *q)
 124{
 125        return 0;
 126}
 127static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
 128{
 129}
 130static inline u64 wbt_default_latency_nsec(struct request_queue *q)
 131{
 132        return 0;
 133}
 134
 135#endif /* CONFIG_BLK_WBT */
 136
 137#endif
 138