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_queue_depth(struct request_queue *, unsigned int);
99void wbt_set_write_cache(struct request_queue *, bool);
100
101u64 wbt_default_latency_nsec(struct request_queue *);
102
103#else
104
105static inline void wbt_track(struct request *rq, enum wbt_flags flags)
106{
107}
108static inline int wbt_init(struct request_queue *q)
109{
110 return -EINVAL;
111}
112static inline void wbt_update_limits(struct request_queue *q)
113{
114}
115static inline void wbt_disable_default(struct request_queue *q)
116{
117}
118static inline void wbt_enable_default(struct request_queue *q)
119{
120}
121static inline void wbt_set_queue_depth(struct request_queue *q, unsigned int depth)
122{
123}
124static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
125{
126}
127static inline u64 wbt_get_min_lat(struct request_queue *q)
128{
129 return 0;
130}
131static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
132{
133}
134static inline u64 wbt_default_latency_nsec(struct request_queue *q)
135{
136 return 0;
137}
138
139#endif /* CONFIG_BLK_WBT */
140
141#endif
142