[linux.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,
};

/*
 * 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,
};

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;

	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;

	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
d62118b6 JA	24	/*
	25	* Enable states. Either off, or on by default (done at init time),
	26	* or on through manual setup in sysfs.
	27	*/
	28	enum {
	29	WBT_STATE_ON_DEFAULT = 1,
	30	WBT_STATE_ON_MANUAL = 2,
	31	};
	32
e34cbd30 JA	33	static inline void wbt_clear_state(struct blk_issue_stat *stat)
	34	{
	35	stat->time &= BLK_STAT_TIME_MASK;
	36	}
	37
	38	static inline enum wbt_flags wbt_stat_to_mask(struct blk_issue_stat *stat)
	39	{
	40	return (stat->time & BLK_STAT_MASK) >> BLK_STAT_SHIFT;
	41	}
	42
	43	static inline void wbt_track(struct blk_issue_stat *stat, enum wbt_flags wb_acct)
	44	{
	45	stat->time \|= ((u64) wb_acct) << BLK_STAT_SHIFT;
	46	}
	47
	48	static inline bool wbt_is_tracked(struct blk_issue_stat *stat)
	49	{
	50	return (stat->time >> BLK_STAT_SHIFT) & WBT_TRACKED;
	51	}
	52
	53	static inline bool wbt_is_read(struct blk_issue_stat *stat)
	54	{
	55	return (stat->time >> BLK_STAT_SHIFT) & WBT_READ;
	56	}
	57
e34cbd30 JA	58	struct rq_wait {
	59	wait_queue_head_t wait;
	60	atomic_t inflight;
	61	};
	62
	63	struct rq_wb {
	64	/*
	65	* Settings that govern how we throttle
	66	*/
	67	unsigned int wb_background; /* background writeback */
	68	unsigned int wb_normal; /* normal writeback */
	69	unsigned int wb_max; /* max throughput writeback */
	70	int scale_step;
	71	bool scaled_max;
	72
d62118b6 JA	73	short enable_state; /* WBT_STATE_* */
d62118b6 JA	74
e34cbd30 JA	75	/*
	76	* Number of consecutive periods where we don't have enough
	77	* information to make a firm scale up/down decision.
	78	*/
	79	unsigned int unknown_cnt;
	80
	81	u64 win_nsec; /* default window size */
	82	u64 cur_win_nsec; /* current window size */
	83
34dbad5d	84	struct blk_stat_callback *cb;
e34cbd30 JA	85
	86	s64 sync_issue;
	87	void *sync_cookie;
	88
	89	unsigned int wc;
	90	unsigned int queue_depth;
	91
	92	unsigned long last_issue; /* last non-throttled issue */
	93	unsigned long last_comp; /* last non-throttled comp */
	94	unsigned long min_lat_nsec;
d8a0cbfd	95	struct request_queue *queue;
e34cbd30	96	struct rq_wait rq_wait[WBT_NUM_RWQ];
e34cbd30 JA	97	};
	98
	99	static inline unsigned int wbt_inflight(struct rq_wb *rwb)
	100	{
	101	unsigned int i, ret = 0;
	102
	103	for (i = 0; i < WBT_NUM_RWQ; i++)
	104	ret += atomic_read(&rwb->rq_wait[i].inflight);
	105
	106	return ret;
	107	}
	108
e34cbd30 JA	109	#ifdef CONFIG_BLK_WBT
	110
	111	void __wbt_done(struct rq_wb *, enum wbt_flags);
	112	void wbt_done(struct rq_wb , struct blk_issue_stat );
	113	enum wbt_flags wbt_wait(struct rq_wb , struct bio , spinlock_t *);
8054b89f	114	int wbt_init(struct request_queue *);
e34cbd30 JA	115	void wbt_exit(struct request_queue *);
	116	void wbt_update_limits(struct rq_wb *);
	117	void wbt_requeue(struct rq_wb , struct blk_issue_stat );
	118	void wbt_issue(struct rq_wb , struct blk_issue_stat );
fa224eed	119	void wbt_disable_default(struct request_queue *);
e34cbd30 JA	120
	121	void wbt_set_queue_depth(struct rq_wb *, unsigned int);
	122	void wbt_set_write_cache(struct rq_wb *, bool);
	123
80e091d1 JA	124	u64 wbt_default_latency_nsec(struct request_queue *);
80e091d1 JA	125
e34cbd30 JA	126	#else
	127
	128	static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
	129	{
	130	}
	131	static inline void wbt_done(struct rq_wb rwb, struct blk_issue_stat stat)
	132	{
	133	}
	134	static inline enum wbt_flags wbt_wait(struct rq_wb rwb, struct bio bio,
	135	spinlock_t *lock)
	136	{
	137	return 0;
	138	}
8054b89f	139	static inline int wbt_init(struct request_queue *q)
e34cbd30 JA	140	{
	141	return -EINVAL;
	142	}
	143	static inline void wbt_exit(struct request_queue *q)
	144	{
	145	}
	146	static inline void wbt_update_limits(struct rq_wb *rwb)
	147	{
	148	}
	149	static inline void wbt_requeue(struct rq_wb rwb, struct blk_issue_stat stat)
	150	{
	151	}
	152	static inline void wbt_issue(struct rq_wb rwb, struct blk_issue_stat stat)
	153	{
	154	}
fa224eed	155	static inline void wbt_disable_default(struct request_queue *q)
e34cbd30 JA	156	{
	157	}
	158	static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
	159	{
	160	}
	161	static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
	162	{
	163	}
80e091d1 JA	164	static inline u64 wbt_default_latency_nsec(struct request_queue *q)
	165	{
	166	return 0;
	167	}
e34cbd30 JA	168
	169	#endif /* CONFIG_BLK_WBT */
	170
	171	#endif