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