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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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
12enum 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
20enum {
21 WBT_NUM_RWQ = 2,
22};
23
24/*
25 * Enable states. Either off, or on by default (done at init time),
26 * or on through manual setup in sysfs.
27 */
28enum {
29 WBT_STATE_ON_DEFAULT = 1,
30 WBT_STATE_ON_MANUAL = 2,
31};
32
33static inline void wbt_clear_state(struct blk_issue_stat *stat)
34{
35 stat->stat &= ~BLK_STAT_RES_MASK;
36}
37
38static inline enum wbt_flags wbt_stat_to_mask(struct blk_issue_stat *stat)
39{
40 return (stat->stat & BLK_STAT_RES_MASK) >> BLK_STAT_RES_SHIFT;
41}
42
43static inline void wbt_track(struct blk_issue_stat *stat, enum wbt_flags wb_acct)
44{
45 stat->stat |= ((u64) wb_acct) << BLK_STAT_RES_SHIFT;
46}
47
48static inline bool wbt_is_tracked(struct blk_issue_stat *stat)
49{
50 return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_TRACKED;
51}
52
53static inline bool wbt_is_read(struct blk_issue_stat *stat)
54{
55 return (stat->stat >> BLK_STAT_RES_SHIFT) & WBT_READ;
56}
57
58struct rq_wait {
59 wait_queue_head_t wait;
60 atomic_t inflight;
61};
62
63struct 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
73 short enable_state; /* WBT_STATE_* */
74
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
84 struct blk_stat_callback *cb;
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;
95 struct request_queue *queue;
96 struct rq_wait rq_wait[WBT_NUM_RWQ];
97};
98
99static 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
109#ifdef CONFIG_BLK_WBT
110
111void __wbt_done(struct rq_wb *, enum wbt_flags);
112void wbt_done(struct rq_wb *, struct blk_issue_stat *);
113enum wbt_flags wbt_wait(struct rq_wb *, struct bio *, spinlock_t *);
114int wbt_init(struct request_queue *);
115void wbt_exit(struct request_queue *);
116void wbt_update_limits(struct rq_wb *);
117void wbt_requeue(struct rq_wb *, struct blk_issue_stat *);
118void wbt_issue(struct rq_wb *, struct blk_issue_stat *);
119void wbt_disable_default(struct request_queue *);
120void wbt_enable_default(struct request_queue *);
121
122void wbt_set_queue_depth(struct rq_wb *, unsigned int);
123void wbt_set_write_cache(struct rq_wb *, bool);
124
125u64 wbt_default_latency_nsec(struct request_queue *);
126
127#else
128
129static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
130{
131}
132static inline void wbt_done(struct rq_wb *rwb, struct blk_issue_stat *stat)
133{
134}
135static inline enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio,
136 spinlock_t *lock)
137{
138 return 0;
139}
140static inline int wbt_init(struct request_queue *q)
141{
142 return -EINVAL;
143}
144static inline void wbt_exit(struct request_queue *q)
145{
146}
147static inline void wbt_update_limits(struct rq_wb *rwb)
148{
149}
150static inline void wbt_requeue(struct rq_wb *rwb, struct blk_issue_stat *stat)
151{
152}
153static inline void wbt_issue(struct rq_wb *rwb, struct blk_issue_stat *stat)
154{
155}
156static inline void wbt_disable_default(struct request_queue *q)
157{
158}
159static inline void wbt_enable_default(struct request_queue *q)
160{
161}
162static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
163{
164}
165static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
166{
167}
168static inline u64 wbt_default_latency_nsec(struct request_queue *q)
169{
170 return 0;
171}
172
173#endif /* CONFIG_BLK_WBT */
174
175#endif