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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef WB_THROTTLE_H
#define WB_THROTTLE_H
#include <linux/kernel.h>
#include <linux/atomic.h>
#include <linux/wait.h>
#include <linux/timer.h>
#include <linux/ktime.h>
#include "blk-stat.h"
#include "blk-rq-qos.h"
enum wbt_flags {
WBT_TRACKED = 1, /* write, tracked for throttling */
WBT_READ = 2, /* read */
WBT_KSWAPD = 4, /* write, from kswapd */
WBT_DISCARD = 8, /* discard */
WBT_NR_BITS = 4, /* number of bits */
};
enum {
WBT_RWQ_BG = 0,
WBT_RWQ_KSWAPD,
WBT_RWQ_DISCARD,
WBT_NUM_RWQ,
};
/*
* Enable states. Either off, or on by default (done at init time),
* or on through manual setup in sysfs.
*/
enum {
WBT_STATE_ON_DEFAULT = 1,
WBT_STATE_ON_MANUAL = 2,
};
struct rq_wb {
/*
* Settings that govern how we throttle
*/
unsigned int wb_background; /* background writeback */
unsigned int wb_normal; /* normal writeback */
short enable_state; /* WBT_STATE_* */
/*
* Number of consecutive periods where we don't have enough
* information to make a firm scale up/down decision.
*/
unsigned int unknown_cnt;
u64 win_nsec; /* default window size */
u64 cur_win_nsec; /* current window size */
struct blk_stat_callback *cb;
u64 sync_issue;
void *sync_cookie;
unsigned int wc;
unsigned long last_issue; /* last non-throttled issue */
unsigned long last_comp; /* last non-throttled comp */
unsigned long min_lat_nsec;
struct rq_qos rqos;
struct rq_wait rq_wait[WBT_NUM_RWQ];
struct rq_depth rq_depth;
};
static inline struct rq_wb *RQWB(struct rq_qos *rqos)
{
return container_of(rqos, struct rq_wb, rqos);
}
static inline unsigned int wbt_inflight(struct rq_wb *rwb)
{
unsigned int i, ret = 0;
for (i = 0; i < WBT_NUM_RWQ; i++)
ret += atomic_read(&rwb->rq_wait[i].inflight);
return ret;
}
#ifdef CONFIG_BLK_WBT
int wbt_init(struct request_queue *);
void wbt_disable_default(struct request_queue *);
void wbt_enable_default(struct request_queue *);
u64 wbt_get_min_lat(struct request_queue *q);
void wbt_set_min_lat(struct request_queue *q, u64 val);
void wbt_set_write_cache(struct request_queue *, bool);
u64 wbt_default_latency_nsec(struct request_queue *);
#else
static inline void wbt_track(struct request *rq, enum wbt_flags flags)
{
}
static inline int wbt_init(struct request_queue *q)
{
return -EINVAL;
}
static inline void wbt_disable_default(struct request_queue *q)
{
}
static inline void wbt_enable_default(struct request_queue *q)
{
}
static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
{
}
static inline u64 wbt_get_min_lat(struct request_queue *q)
{
return 0;
}
static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
{
}
static inline u64 wbt_default_latency_nsec(struct request_queue *q)
{
return 0;
}
#endif /* CONFIG_BLK_WBT */
#endif
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