[mirror_ubuntu-zesty-kernel.git] / block / blk-wbt.h

#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
Commit	Line	Data
e34cbd30 JA	1	#ifndef WB_THROTTLE_H
	2	#define WB_THROTTLE_H
	3
	4	#include <linux/kernel.h>
	5	#include <linux/atomic.h>
	6	#include <linux/wait.h>
	7	#include <linux/timer.h>
	8	#include <linux/ktime.h>
	9
	10	#include "blk-stat.h"
	11
	12	enum wbt_flags {
	13	WBT_TRACKED = 1, /* write, tracked for throttling */
	14	WBT_READ = 2, /* read */
	15	WBT_KSWAPD = 4, /* write, from kswapd */
	16
	17	WBT_NR_BITS = 3, /* number of bits */
	18	};
	19
	20	enum {
	21	WBT_NUM_RWQ = 2,
	22	};
	23
	24	static inline void wbt_clear_state(struct blk_issue_stat *stat)
	25	{
	26	stat->time &= BLK_STAT_TIME_MASK;
	27	}
	28
	29	static inline enum wbt_flags wbt_stat_to_mask(struct blk_issue_stat *stat)
	30	{
	31	return (stat->time & BLK_STAT_MASK) >> BLK_STAT_SHIFT;
	32	}
	33
	34	static inline void wbt_track(struct blk_issue_stat *stat, enum wbt_flags wb_acct)
	35	{
	36	stat->time \|= ((u64) wb_acct) << BLK_STAT_SHIFT;
	37	}
	38
	39	static inline bool wbt_is_tracked(struct blk_issue_stat *stat)
	40	{
	41	return (stat->time >> BLK_STAT_SHIFT) & WBT_TRACKED;
	42	}
	43
	44	static inline bool wbt_is_read(struct blk_issue_stat *stat)
	45	{
	46	return (stat->time >> BLK_STAT_SHIFT) & WBT_READ;
	47	}
	48
e34cbd30 JA	49	struct rq_wait {
	50	wait_queue_head_t wait;
	51	atomic_t inflight;
	52	};
	53
	54	struct rq_wb {
	55	/*
	56	* Settings that govern how we throttle
	57	*/
	58	unsigned int wb_background; /* background writeback */
	59	unsigned int wb_normal; /* normal writeback */
	60	unsigned int wb_max; /* max throughput writeback */
	61	int scale_step;
	62	bool scaled_max;
	63
	64	/*
	65	* Number of consecutive periods where we don't have enough
	66	* information to make a firm scale up/down decision.
	67	*/
	68	unsigned int unknown_cnt;
	69
	70	u64 win_nsec; /* default window size */
	71	u64 cur_win_nsec; /* current window size */
	72
	73	struct timer_list window_timer;
	74
	75	s64 sync_issue;
	76	void *sync_cookie;
	77
	78	unsigned int wc;
	79	unsigned int queue_depth;
	80
	81	unsigned long last_issue; /* last non-throttled issue */
	82	unsigned long last_comp; /* last non-throttled comp */
	83	unsigned long min_lat_nsec;
d8a0cbfd	84	struct request_queue *queue;
e34cbd30	85	struct rq_wait rq_wait[WBT_NUM_RWQ];
e34cbd30 JA	86	};
	87
	88	static inline unsigned int wbt_inflight(struct rq_wb *rwb)
	89	{
	90	unsigned int i, ret = 0;
	91
	92	for (i = 0; i < WBT_NUM_RWQ; i++)
	93	ret += atomic_read(&rwb->rq_wait[i].inflight);
	94
	95	return ret;
	96	}
	97
e34cbd30 JA	98	#ifdef CONFIG_BLK_WBT
	99
	100	void __wbt_done(struct rq_wb *, enum wbt_flags);
	101	void wbt_done(struct rq_wb , struct blk_issue_stat );
	102	enum wbt_flags wbt_wait(struct rq_wb , struct bio , spinlock_t *);
8054b89f	103	int wbt_init(struct request_queue *);
e34cbd30 JA	104	void wbt_exit(struct request_queue *);
	105	void wbt_update_limits(struct rq_wb *);
	106	void wbt_requeue(struct rq_wb , struct blk_issue_stat );
	107	void wbt_issue(struct rq_wb , struct blk_issue_stat );
fa224eed	108	void wbt_disable_default(struct request_queue *);
e34cbd30 JA	109
	110	void wbt_set_queue_depth(struct rq_wb *, unsigned int);
	111	void wbt_set_write_cache(struct rq_wb *, bool);
	112
80e091d1 JA	113	u64 wbt_default_latency_nsec(struct request_queue *);
80e091d1 JA	114
e34cbd30 JA	115	#else
	116
	117	static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
	118	{
	119	}
	120	static inline void wbt_done(struct rq_wb rwb, struct blk_issue_stat stat)
	121	{
	122	}
	123	static inline enum wbt_flags wbt_wait(struct rq_wb rwb, struct bio bio,
	124	spinlock_t *lock)
	125	{
	126	return 0;
	127	}
8054b89f	128	static inline int wbt_init(struct request_queue *q)
e34cbd30 JA	129	{
	130	return -EINVAL;
	131	}
	132	static inline void wbt_exit(struct request_queue *q)
	133	{
	134	}
	135	static inline void wbt_update_limits(struct rq_wb *rwb)
	136	{
	137	}
	138	static inline void wbt_requeue(struct rq_wb rwb, struct blk_issue_stat stat)
	139	{
	140	}
	141	static inline void wbt_issue(struct rq_wb rwb, struct blk_issue_stat stat)
	142	{
	143	}
fa224eed	144	static inline void wbt_disable_default(struct request_queue *q)
e34cbd30 JA	145	{
	146	}
	147	static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
	148	{
	149	}
	150	static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
	151	{
	152	}
80e091d1 JA	153	static inline u64 wbt_default_latency_nsec(struct request_queue *q)
	154	{
	155	return 0;
	156	}
e34cbd30 JA	157
	158	#endif /* CONFIG_BLK_WBT */
	159
	160	#endif