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#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"
enum wbt_flags {
WBT_TRACKED = 1, /* write, tracked for throttling */
WBT_READ = 2, /* read */
WBT_KSWAPD = 4, /* write, from kswapd */
WBT_NR_BITS = 3, /* number of bits */
};
enum {
WBT_NUM_RWQ = 2,
};
static inline void wbt_clear_state(struct blk_issue_stat *stat)
{
stat->time &= BLK_STAT_TIME_MASK;
}
static inline enum wbt_flags wbt_stat_to_mask(struct blk_issue_stat *stat)
{
return (stat->time & BLK_STAT_MASK) >> BLK_STAT_SHIFT;
}
static inline void wbt_track(struct blk_issue_stat *stat, enum wbt_flags wb_acct)
{
stat->time |= ((u64) wb_acct) << BLK_STAT_SHIFT;
}
static inline bool wbt_is_tracked(struct blk_issue_stat *stat)
{
return (stat->time >> BLK_STAT_SHIFT) & WBT_TRACKED;
}
static inline bool wbt_is_read(struct blk_issue_stat *stat)
{
return (stat->time >> BLK_STAT_SHIFT) & WBT_READ;
}
struct rq_wait {
wait_queue_head_t wait;
atomic_t inflight;
};
struct rq_wb {
/*
* Settings that govern how we throttle
*/
unsigned int wb_background; /* background writeback */
unsigned int wb_normal; /* normal writeback */
unsigned int wb_max; /* max throughput writeback */
int scale_step;
bool scaled_max;
/*
* 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 timer_list window_timer;
s64 sync_issue;
void *sync_cookie;
unsigned int wc;
unsigned int queue_depth;
unsigned long last_issue; /* last non-throttled issue */
unsigned long last_comp; /* last non-throttled comp */
unsigned long min_lat_nsec;
struct request_queue *queue;
struct rq_wait rq_wait[WBT_NUM_RWQ];
};
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
void __wbt_done(struct rq_wb *, enum wbt_flags);
void wbt_done(struct rq_wb *, struct blk_issue_stat *);
enum wbt_flags wbt_wait(struct rq_wb *, struct bio *, spinlock_t *);
int wbt_init(struct request_queue *);
void wbt_exit(struct request_queue *);
void wbt_update_limits(struct rq_wb *);
void wbt_requeue(struct rq_wb *, struct blk_issue_stat *);
void wbt_issue(struct rq_wb *, struct blk_issue_stat *);
void wbt_disable_default(struct request_queue *);
void wbt_set_queue_depth(struct rq_wb *, unsigned int);
void wbt_set_write_cache(struct rq_wb *, bool);
u64 wbt_default_latency_nsec(struct request_queue *);
#else
static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
{
}
static inline void wbt_done(struct rq_wb *rwb, struct blk_issue_stat *stat)
{
}
static inline enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio,
spinlock_t *lock)
{
return 0;
}
static inline int wbt_init(struct request_queue *q)
{
return -EINVAL;
}
static inline void wbt_exit(struct request_queue *q)
{
}
static inline void wbt_update_limits(struct rq_wb *rwb)
{
}
static inline void wbt_requeue(struct rq_wb *rwb, struct blk_issue_stat *stat)
{
}
static inline void wbt_issue(struct rq_wb *rwb, struct blk_issue_stat *stat)
{
}
static inline void wbt_disable_default(struct request_queue *q)
{
}
static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
{
}
static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
{
}
static inline u64 wbt_default_latency_nsec(struct request_queue *q)
{
return 0;
}
#endif /* CONFIG_BLK_WBT */
#endif
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