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 * If current state is WBT_STATE_ON/OFF_DEFAULT, it can be covered to any other
 32 * state, if current state is WBT_STATE_ON/OFF_MANUAL, it can only be covered
 33 * to WBT_STATE_OFF/ON_MANUAL.
 34 */
 35enum {
 36	WBT_STATE_ON_DEFAULT	= 1,	/* on by default */
 37	WBT_STATE_ON_MANUAL	= 2,	/* on manually by sysfs */
 38	WBT_STATE_OFF_DEFAULT	= 3,	/* off by default */
 39	WBT_STATE_OFF_MANUAL	= 4,	/* off manually by sysfs */
 40};
 41
 42struct rq_wb {
 43	/*
 44	 * Settings that govern how we throttle
 45	 */
 46	unsigned int wb_background;		/* background writeback */
 47	unsigned int wb_normal;			/* normal writeback */
 48
 49	short enable_state;			/* WBT_STATE_* */
 50
 51	/*
 52	 * Number of consecutive periods where we don't have enough
 53	 * information to make a firm scale up/down decision.
 54	 */
 55	unsigned int unknown_cnt;
 56
 57	u64 win_nsec;				/* default window size */
 58	u64 cur_win_nsec;			/* current window size */
 59
 60	struct blk_stat_callback *cb;
 61
 62	u64 sync_issue;
 63	void *sync_cookie;
 64
 65	unsigned int wc;
 66
 67	unsigned long last_issue;		/* last non-throttled issue */
 68	unsigned long last_comp;		/* last non-throttled comp */
 69	unsigned long min_lat_nsec;
 70	struct rq_qos rqos;
 71	struct rq_wait rq_wait[WBT_NUM_RWQ];
 72	struct rq_depth rq_depth;
 73};
 74
 75static inline struct rq_wb *RQWB(struct rq_qos *rqos)
 76{
 77	return container_of(rqos, struct rq_wb, rqos);
 78}
 79
 80static inline unsigned int wbt_inflight(struct rq_wb *rwb)
 81{
 82	unsigned int i, ret = 0;
 83
 84	for (i = 0; i < WBT_NUM_RWQ; i++)
 85		ret += atomic_read(&rwb->rq_wait[i].inflight);
 86
 87	return ret;
 88}
 89
 90
 91#ifdef CONFIG_BLK_WBT
 92
 93int wbt_init(struct request_queue *);
 94void wbt_disable_default(struct request_queue *);
 95void wbt_enable_default(struct request_queue *);
 96
 97u64 wbt_get_min_lat(struct request_queue *q);
 98void wbt_set_min_lat(struct request_queue *q, u64 val);
 99bool wbt_disabled(struct request_queue *);
100
101void wbt_set_write_cache(struct request_queue *, bool);
102
103u64 wbt_default_latency_nsec(struct request_queue *);
104
105#else
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}
131static inline bool wbt_disabled(struct request_queue *q)
132{
133	return true;
134}
135
136#endif /* CONFIG_BLK_WBT */
137
138#endif