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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
cf43e6be JA |
2 | #ifndef BLK_STAT_H |
3 | #define BLK_STAT_H | |
4 | ||
34dbad5d OS |
5 | #include <linux/kernel.h> |
6 | #include <linux/blkdev.h> | |
7 | #include <linux/ktime.h> | |
8 | #include <linux/rcupdate.h> | |
9 | #include <linux/timer.h> | |
cf43e6be | 10 | |
34dbad5d OS |
11 | /** |
12 | * struct blk_stat_callback - Block statistics callback. | |
13 | * | |
14 | * A &struct blk_stat_callback is associated with a &struct request_queue. While | |
15 | * @timer is active, that queue's request completion latencies are sorted into | |
16 | * buckets by @bucket_fn and added to a per-cpu buffer, @cpu_stat. When the | |
17 | * timer fires, @cpu_stat is flushed to @stat and @timer_fn is invoked. | |
18 | */ | |
19 | struct blk_stat_callback { | |
20 | /* | |
21 | * @list: RCU list of callbacks for a &struct request_queue. | |
22 | */ | |
23 | struct list_head list; | |
24 | ||
25 | /** | |
26 | * @timer: Timer for the next callback invocation. | |
27 | */ | |
28 | struct timer_list timer; | |
29 | ||
30 | /** | |
31 | * @cpu_stat: Per-cpu statistics buckets. | |
32 | */ | |
33 | struct blk_rq_stat __percpu *cpu_stat; | |
34 | ||
35 | /** | |
36 | * @bucket_fn: Given a request, returns which statistics bucket it | |
a37244e4 SB |
37 | * should be accounted under. Return -1 for no bucket for this |
38 | * request. | |
34dbad5d | 39 | */ |
a37244e4 | 40 | int (*bucket_fn)(const struct request *); |
34dbad5d OS |
41 | |
42 | /** | |
43 | * @buckets: Number of statistics buckets. | |
44 | */ | |
45 | unsigned int buckets; | |
46 | ||
47 | /** | |
48 | * @stat: Array of statistics buckets. | |
49 | */ | |
50 | struct blk_rq_stat *stat; | |
51 | ||
52 | /** | |
53 | * @fn: Callback function. | |
54 | */ | |
55 | void (*timer_fn)(struct blk_stat_callback *); | |
56 | ||
57 | /** | |
58 | * @data: Private pointer for the user. | |
59 | */ | |
60 | void *data; | |
61 | ||
62 | struct rcu_head rcu; | |
63 | }; | |
64 | ||
65 | struct blk_queue_stats *blk_alloc_queue_stats(void); | |
66 | void blk_free_queue_stats(struct blk_queue_stats *); | |
67 | ||
522a7775 | 68 | void blk_stat_add(struct request *rq, u64 now); |
34dbad5d | 69 | |
b9147dd1 SL |
70 | /* record time/size info in request but not add a callback */ |
71 | void blk_stat_enable_accounting(struct request_queue *q); | |
72 | ||
34dbad5d OS |
73 | /** |
74 | * blk_stat_alloc_callback() - Allocate a block statistics callback. | |
75 | * @timer_fn: Timer callback function. | |
76 | * @bucket_fn: Bucket callback function. | |
77 | * @buckets: Number of statistics buckets. | |
78 | * @data: Value for the @data field of the &struct blk_stat_callback. | |
79 | * | |
80 | * See &struct blk_stat_callback for details on the callback functions. | |
81 | * | |
82 | * Return: &struct blk_stat_callback on success or NULL on ENOMEM. | |
83 | */ | |
84 | struct blk_stat_callback * | |
85 | blk_stat_alloc_callback(void (*timer_fn)(struct blk_stat_callback *), | |
a37244e4 | 86 | int (*bucket_fn)(const struct request *), |
34dbad5d OS |
87 | unsigned int buckets, void *data); |
88 | ||
89 | /** | |
90 | * blk_stat_add_callback() - Add a block statistics callback to be run on a | |
91 | * request queue. | |
92 | * @q: The request queue. | |
93 | * @cb: The callback. | |
94 | * | |
95 | * Note that a single &struct blk_stat_callback can only be added to a single | |
96 | * &struct request_queue. | |
97 | */ | |
98 | void blk_stat_add_callback(struct request_queue *q, | |
99 | struct blk_stat_callback *cb); | |
100 | ||
101 | /** | |
102 | * blk_stat_remove_callback() - Remove a block statistics callback from a | |
103 | * request queue. | |
104 | * @q: The request queue. | |
105 | * @cb: The callback. | |
106 | * | |
107 | * When this returns, the callback is not running on any CPUs and will not be | |
108 | * called again unless readded. | |
109 | */ | |
110 | void blk_stat_remove_callback(struct request_queue *q, | |
111 | struct blk_stat_callback *cb); | |
112 | ||
113 | /** | |
114 | * blk_stat_free_callback() - Free a block statistics callback. | |
115 | * @cb: The callback. | |
116 | * | |
117 | * @cb may be NULL, in which case this does nothing. If it is not NULL, @cb must | |
118 | * not be associated with a request queue. I.e., if it was previously added with | |
119 | * blk_stat_add_callback(), it must also have been removed since then with | |
120 | * blk_stat_remove_callback(). | |
121 | */ | |
122 | void blk_stat_free_callback(struct blk_stat_callback *cb); | |
123 | ||
124 | /** | |
125 | * blk_stat_is_active() - Check if a block statistics callback is currently | |
126 | * gathering statistics. | |
127 | * @cb: The callback. | |
128 | */ | |
129 | static inline bool blk_stat_is_active(struct blk_stat_callback *cb) | |
130 | { | |
131 | return timer_pending(&cb->timer); | |
132 | } | |
133 | ||
134 | /** | |
135 | * blk_stat_activate_nsecs() - Gather block statistics during a time window in | |
136 | * nanoseconds. | |
137 | * @cb: The callback. | |
138 | * @nsecs: Number of nanoseconds to gather statistics for. | |
139 | * | |
140 | * The timer callback will be called when the window expires. | |
141 | */ | |
142 | static inline void blk_stat_activate_nsecs(struct blk_stat_callback *cb, | |
143 | u64 nsecs) | |
144 | { | |
145 | mod_timer(&cb->timer, jiffies + nsecs_to_jiffies(nsecs)); | |
146 | } | |
147 | ||
148 | /** | |
149 | * blk_stat_activate_msecs() - Gather block statistics during a time window in | |
150 | * milliseconds. | |
151 | * @cb: The callback. | |
152 | * @msecs: Number of milliseconds to gather statistics for. | |
153 | * | |
154 | * The timer callback will be called when the window expires. | |
155 | */ | |
156 | static inline void blk_stat_activate_msecs(struct blk_stat_callback *cb, | |
157 | unsigned int msecs) | |
158 | { | |
159 | mod_timer(&cb->timer, jiffies + msecs_to_jiffies(msecs)); | |
160 | } | |
161 | ||
2ecbf456 JB |
162 | void blk_rq_stat_add(struct blk_rq_stat *, u64); |
163 | void blk_rq_stat_sum(struct blk_rq_stat *, struct blk_rq_stat *); | |
164 | void blk_rq_stat_init(struct blk_rq_stat *); | |
165 | ||
cf43e6be | 166 | #endif |