Commit | Line | Data |
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3dcf60bc | 1 | // SPDX-License-Identifier: GPL-2.0 |
cf43e6be JA |
2 | /* |
3 | * Block stat tracking code | |
4 | * | |
5 | * Copyright (C) 2016 Jens Axboe | |
6 | */ | |
7 | #include <linux/kernel.h> | |
34dbad5d | 8 | #include <linux/rculist.h> |
cf43e6be JA |
9 | |
10 | #include "blk-stat.h" | |
11 | #include "blk-mq.h" | |
b9147dd1 | 12 | #include "blk.h" |
cf43e6be | 13 | |
34dbad5d OS |
14 | struct blk_queue_stats { |
15 | struct list_head callbacks; | |
16 | spinlock_t lock; | |
68497092 | 17 | int accounting; |
34dbad5d OS |
18 | }; |
19 | ||
2ecbf456 | 20 | void blk_rq_stat_init(struct blk_rq_stat *stat) |
34dbad5d OS |
21 | { |
22 | stat->min = -1ULL; | |
23 | stat->max = stat->nr_samples = stat->mean = 0; | |
eca8b53a | 24 | stat->batch = 0; |
cf43e6be JA |
25 | } |
26 | ||
eca8b53a | 27 | /* src is a per-cpu stat, mean isn't initialized */ |
2ecbf456 | 28 | void blk_rq_stat_sum(struct blk_rq_stat *dst, struct blk_rq_stat *src) |
cf43e6be | 29 | { |
93f52fbe | 30 | if (dst->nr_samples + src->nr_samples <= dst->nr_samples) |
cf43e6be JA |
31 | return; |
32 | ||
cf43e6be JA |
33 | dst->min = min(dst->min, src->min); |
34 | dst->max = max(dst->max, src->max); | |
35 | ||
eca8b53a SL |
36 | dst->mean = div_u64(src->batch + dst->mean * dst->nr_samples, |
37 | dst->nr_samples + src->nr_samples); | |
38 | ||
cf43e6be JA |
39 | dst->nr_samples += src->nr_samples; |
40 | } | |
41 | ||
2ecbf456 | 42 | void blk_rq_stat_add(struct blk_rq_stat *stat, u64 value) |
cf43e6be | 43 | { |
34dbad5d OS |
44 | stat->min = min(stat->min, value); |
45 | stat->max = max(stat->max, value); | |
34dbad5d | 46 | stat->batch += value; |
eca8b53a | 47 | stat->nr_samples++; |
cf43e6be JA |
48 | } |
49 | ||
522a7775 | 50 | void blk_stat_add(struct request *rq, u64 now) |
cf43e6be | 51 | { |
34dbad5d OS |
52 | struct request_queue *q = rq->q; |
53 | struct blk_stat_callback *cb; | |
54 | struct blk_rq_stat *stat; | |
8148f0b5 | 55 | int bucket, cpu; |
522a7775 | 56 | u64 value; |
34dbad5d | 57 | |
544ccc8d | 58 | value = (now >= rq->io_start_time_ns) ? now - rq->io_start_time_ns : 0; |
34dbad5d OS |
59 | |
60 | rcu_read_lock(); | |
8148f0b5 | 61 | cpu = get_cpu(); |
34dbad5d | 62 | list_for_each_entry_rcu(cb, &q->stats->callbacks, list) { |
d3738123 JA |
63 | if (!blk_stat_is_active(cb)) |
64 | continue; | |
65 | ||
66 | bucket = cb->bucket_fn(rq); | |
67 | if (bucket < 0) | |
68 | continue; | |
69 | ||
8148f0b5 | 70 | stat = &per_cpu_ptr(cb->cpu_stat, cpu)[bucket]; |
2ecbf456 | 71 | blk_rq_stat_add(stat, value); |
cf43e6be | 72 | } |
8148f0b5 | 73 | put_cpu(); |
34dbad5d | 74 | rcu_read_unlock(); |
cf43e6be JA |
75 | } |
76 | ||
e99e88a9 | 77 | static void blk_stat_timer_fn(struct timer_list *t) |
cf43e6be | 78 | { |
e99e88a9 | 79 | struct blk_stat_callback *cb = from_timer(cb, t, timer); |
34dbad5d OS |
80 | unsigned int bucket; |
81 | int cpu; | |
cf43e6be | 82 | |
34dbad5d | 83 | for (bucket = 0; bucket < cb->buckets; bucket++) |
2ecbf456 | 84 | blk_rq_stat_init(&cb->stat[bucket]); |
cf43e6be | 85 | |
34dbad5d OS |
86 | for_each_online_cpu(cpu) { |
87 | struct blk_rq_stat *cpu_stat; | |
7cd54aa8 | 88 | |
34dbad5d OS |
89 | cpu_stat = per_cpu_ptr(cb->cpu_stat, cpu); |
90 | for (bucket = 0; bucket < cb->buckets; bucket++) { | |
2ecbf456 JB |
91 | blk_rq_stat_sum(&cb->stat[bucket], &cpu_stat[bucket]); |
92 | blk_rq_stat_init(&cpu_stat[bucket]); | |
cf43e6be | 93 | } |
34dbad5d | 94 | } |
cf43e6be | 95 | |
34dbad5d | 96 | cb->timer_fn(cb); |
cf43e6be JA |
97 | } |
98 | ||
34dbad5d OS |
99 | struct blk_stat_callback * |
100 | blk_stat_alloc_callback(void (*timer_fn)(struct blk_stat_callback *), | |
a37244e4 | 101 | int (*bucket_fn)(const struct request *), |
34dbad5d | 102 | unsigned int buckets, void *data) |
cf43e6be | 103 | { |
34dbad5d | 104 | struct blk_stat_callback *cb; |
cf43e6be | 105 | |
34dbad5d OS |
106 | cb = kmalloc(sizeof(*cb), GFP_KERNEL); |
107 | if (!cb) | |
108 | return NULL; | |
cf43e6be | 109 | |
34dbad5d OS |
110 | cb->stat = kmalloc_array(buckets, sizeof(struct blk_rq_stat), |
111 | GFP_KERNEL); | |
112 | if (!cb->stat) { | |
113 | kfree(cb); | |
114 | return NULL; | |
115 | } | |
116 | cb->cpu_stat = __alloc_percpu(buckets * sizeof(struct blk_rq_stat), | |
117 | __alignof__(struct blk_rq_stat)); | |
118 | if (!cb->cpu_stat) { | |
119 | kfree(cb->stat); | |
120 | kfree(cb); | |
121 | return NULL; | |
122 | } | |
cf43e6be | 123 | |
34dbad5d OS |
124 | cb->timer_fn = timer_fn; |
125 | cb->bucket_fn = bucket_fn; | |
126 | cb->data = data; | |
127 | cb->buckets = buckets; | |
e99e88a9 | 128 | timer_setup(&cb->timer, blk_stat_timer_fn, 0); |
34dbad5d OS |
129 | |
130 | return cb; | |
cf43e6be JA |
131 | } |
132 | ||
34dbad5d OS |
133 | void blk_stat_add_callback(struct request_queue *q, |
134 | struct blk_stat_callback *cb) | |
cf43e6be | 135 | { |
34dbad5d | 136 | unsigned int bucket; |
e11d80a8 | 137 | unsigned long flags; |
34dbad5d | 138 | int cpu; |
cf43e6be | 139 | |
34dbad5d OS |
140 | for_each_possible_cpu(cpu) { |
141 | struct blk_rq_stat *cpu_stat; | |
cf43e6be | 142 | |
34dbad5d OS |
143 | cpu_stat = per_cpu_ptr(cb->cpu_stat, cpu); |
144 | for (bucket = 0; bucket < cb->buckets; bucket++) | |
2ecbf456 | 145 | blk_rq_stat_init(&cpu_stat[bucket]); |
34dbad5d | 146 | } |
cf43e6be | 147 | |
e11d80a8 | 148 | spin_lock_irqsave(&q->stats->lock, flags); |
34dbad5d | 149 | list_add_tail_rcu(&cb->list, &q->stats->callbacks); |
7dfdbc73 | 150 | blk_queue_flag_set(QUEUE_FLAG_STATS, q); |
e11d80a8 | 151 | spin_unlock_irqrestore(&q->stats->lock, flags); |
34dbad5d | 152 | } |
cf43e6be | 153 | |
34dbad5d OS |
154 | void blk_stat_remove_callback(struct request_queue *q, |
155 | struct blk_stat_callback *cb) | |
156 | { | |
e11d80a8 TH |
157 | unsigned long flags; |
158 | ||
159 | spin_lock_irqsave(&q->stats->lock, flags); | |
34dbad5d | 160 | list_del_rcu(&cb->list); |
68497092 | 161 | if (list_empty(&q->stats->callbacks) && !q->stats->accounting) |
7dfdbc73 | 162 | blk_queue_flag_clear(QUEUE_FLAG_STATS, q); |
e11d80a8 | 163 | spin_unlock_irqrestore(&q->stats->lock, flags); |
cf43e6be | 164 | |
34dbad5d | 165 | del_timer_sync(&cb->timer); |
cf43e6be JA |
166 | } |
167 | ||
34dbad5d | 168 | static void blk_stat_free_callback_rcu(struct rcu_head *head) |
cf43e6be | 169 | { |
34dbad5d OS |
170 | struct blk_stat_callback *cb; |
171 | ||
172 | cb = container_of(head, struct blk_stat_callback, rcu); | |
173 | free_percpu(cb->cpu_stat); | |
174 | kfree(cb->stat); | |
175 | kfree(cb); | |
cf43e6be JA |
176 | } |
177 | ||
34dbad5d | 178 | void blk_stat_free_callback(struct blk_stat_callback *cb) |
cf43e6be | 179 | { |
a83b576c JA |
180 | if (cb) |
181 | call_rcu(&cb->rcu, blk_stat_free_callback_rcu); | |
cf43e6be JA |
182 | } |
183 | ||
68497092 JA |
184 | void blk_stat_disable_accounting(struct request_queue *q) |
185 | { | |
186 | unsigned long flags; | |
187 | ||
188 | spin_lock_irqsave(&q->stats->lock, flags); | |
20de765f | 189 | if (!--q->stats->accounting && list_empty(&q->stats->callbacks)) |
68497092 JA |
190 | blk_queue_flag_clear(QUEUE_FLAG_STATS, q); |
191 | spin_unlock_irqrestore(&q->stats->lock, flags); | |
192 | } | |
193 | EXPORT_SYMBOL_GPL(blk_stat_disable_accounting); | |
194 | ||
b9147dd1 SL |
195 | void blk_stat_enable_accounting(struct request_queue *q) |
196 | { | |
e11d80a8 TH |
197 | unsigned long flags; |
198 | ||
199 | spin_lock_irqsave(&q->stats->lock, flags); | |
20de765f | 200 | if (!q->stats->accounting++ && list_empty(&q->stats->callbacks)) |
68497092 | 201 | blk_queue_flag_set(QUEUE_FLAG_STATS, q); |
e11d80a8 | 202 | spin_unlock_irqrestore(&q->stats->lock, flags); |
b9147dd1 | 203 | } |
f8232f29 | 204 | EXPORT_SYMBOL_GPL(blk_stat_enable_accounting); |
b9147dd1 | 205 | |
34dbad5d | 206 | struct blk_queue_stats *blk_alloc_queue_stats(void) |
cf43e6be | 207 | { |
34dbad5d OS |
208 | struct blk_queue_stats *stats; |
209 | ||
210 | stats = kmalloc(sizeof(*stats), GFP_KERNEL); | |
211 | if (!stats) | |
212 | return NULL; | |
213 | ||
214 | INIT_LIST_HEAD(&stats->callbacks); | |
215 | spin_lock_init(&stats->lock); | |
68497092 | 216 | stats->accounting = 0; |
34dbad5d OS |
217 | |
218 | return stats; | |
219 | } | |
220 | ||
221 | void blk_free_queue_stats(struct blk_queue_stats *stats) | |
222 | { | |
223 | if (!stats) | |
224 | return; | |
225 | ||
226 | WARN_ON(!list_empty(&stats->callbacks)); | |
cf43e6be | 227 | |
34dbad5d | 228 | kfree(stats); |
cf43e6be | 229 | } |