xref: /kernel/linux/linux-5.10/block/blk-wbt.h (revision 8c2ecf20) 
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	WBT_STATE_OFF_DEFAULT
38};
39
40struct rq_wb {
41	/*
42	 * Settings that govern how we throttle
43	 */
44	unsigned int wb_background;		/* background writeback */
45	unsigned int wb_normal;			/* normal writeback */
46
47	short enable_state;			/* WBT_STATE_* */
48
49	/*
50	 * Number of consecutive periods where we don't have enough
51	 * information to make a firm scale up/down decision.
52	 */
53	unsigned int unknown_cnt;
54
55	u64 win_nsec;				/* default window size */
56	u64 cur_win_nsec;			/* current window size */
57
58	struct blk_stat_callback *cb;
59
60	u64 sync_issue;
61	void *sync_cookie;
62
63	unsigned int wc;
64
65	unsigned long last_issue;		/* last non-throttled issue */
66	unsigned long last_comp;		/* last non-throttled comp */
67	unsigned long min_lat_nsec;
68	struct rq_qos rqos;
69	struct rq_wait rq_wait[WBT_NUM_RWQ];
70	struct rq_depth rq_depth;
71};
72
73static inline struct rq_wb *RQWB(struct rq_qos *rqos)
74{
75	return container_of(rqos, struct rq_wb, rqos);
76}
77
78static inline unsigned int wbt_inflight(struct rq_wb *rwb)
79{
80	unsigned int i, ret = 0;
81
82	for (i = 0; i < WBT_NUM_RWQ; i++)
83		ret += atomic_read(&rwb->rq_wait[i].inflight);
84
85	return ret;
86}
87
88
89#ifdef CONFIG_BLK_WBT
90
91int wbt_init(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_disable_default(struct request_queue *q)
112{
113}
114static inline void wbt_enable_default(struct request_queue *q)
115{
116}
117static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
118{
119}
120static inline u64 wbt_get_min_lat(struct request_queue *q)
121{
122	return 0;
123}
124static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
125{
126}
127static inline u64 wbt_default_latency_nsec(struct request_queue *q)
128{
129	return 0;
130}
131
132#endif /* CONFIG_BLK_WBT */
133
134#endif
135