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>
13 WBT_TRACKED = 1, /* write, tracked for throttling */
14 WBT_READ = 2, /* read */
15 WBT_KSWAPD = 4, /* write, from kswapd */
17 WBT_NR_BITS = 3, /* number of bits */
25 * Enable states. Either off, or on by default (done at init time),
26 * or on through manual setup in sysfs.
29 WBT_STATE_ON_DEFAULT = 1,
30 WBT_STATE_ON_MANUAL = 2,
33 static inline void wbt_clear_state(struct blk_issue_stat *stat)
35 stat->stat &= ~BLK_STAT_RES_MASK;
38 static inline enum wbt_flags wbt_stat_to_mask(struct blk_issue_stat *stat)
40 return (stat->stat & BLK_STAT_RES_MASK) >> BLK_STAT_RES_SHIFT;
43 static inline void wbt_track(struct blk_issue_stat *stat, enum wbt_flags wb_acct)
45 stat->stat |= ((u64) wb_acct) << BLK_STAT_RES_SHIFT;
48 static inline bool wbt_is_tracked(struct blk_issue_stat *stat)
50 return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_TRACKED;
53 static inline bool wbt_is_read(struct blk_issue_stat *stat)
55 return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_READ;
59 wait_queue_head_t wait;
65 * Settings that govern how we throttle
67 unsigned int wb_background; /* background writeback */
68 unsigned int wb_normal; /* normal writeback */
69 unsigned int wb_max; /* max throughput writeback */
73 short enable_state; /* WBT_STATE_* */
76 * Number of consecutive periods where we don't have enough
77 * information to make a firm scale up/down decision.
79 unsigned int unknown_cnt;
81 u64 win_nsec; /* default window size */
82 u64 cur_win_nsec; /* current window size */
84 struct blk_stat_callback *cb;
90 unsigned int queue_depth;
92 unsigned long last_issue; /* last non-throttled issue */
93 unsigned long last_comp; /* last non-throttled comp */
94 unsigned long min_lat_nsec;
95 struct request_queue *queue;
96 struct rq_wait rq_wait[WBT_NUM_RWQ];
99 static inline unsigned int wbt_inflight(struct rq_wb *rwb)
101 unsigned int i, ret = 0;
103 for (i = 0; i < WBT_NUM_RWQ; i++)
104 ret += atomic_read(&rwb->rq_wait[i].inflight);
109 #ifdef CONFIG_BLK_WBT
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 *);
114 int wbt_init(struct request_queue *);
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 *);
119 void wbt_disable_default(struct request_queue *);
120 void wbt_enable_default(struct request_queue *);
122 void wbt_set_queue_depth(struct rq_wb *, unsigned int);
123 void wbt_set_write_cache(struct rq_wb *, bool);
125 u64 wbt_default_latency_nsec(struct request_queue *);
129 static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
132 static inline void wbt_done(struct rq_wb *rwb, struct blk_issue_stat *stat)
135 static inline enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio,
140 static inline int wbt_init(struct request_queue *q)
144 static inline void wbt_exit(struct request_queue *q)
147 static inline void wbt_update_limits(struct rq_wb *rwb)
150 static inline void wbt_requeue(struct rq_wb *rwb, struct blk_issue_stat *stat)
153 static inline void wbt_issue(struct rq_wb *rwb, struct blk_issue_stat *stat)
156 static inline void wbt_disable_default(struct request_queue *q)
159 static inline void wbt_enable_default(struct request_queue *q)
162 static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
165 static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
168 static inline u64 wbt_default_latency_nsec(struct request_queue *q)
173 #endif /* CONFIG_BLK_WBT */