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1 | /* |
2 | * Some low level IO code, and hacks for various block layer limitations | |
3 | * | |
4 | * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> | |
5 | * Copyright 2012 Google, Inc. | |
6 | */ | |
7 | ||
8 | #include "bcache.h" | |
9 | #include "bset.h" | |
10 | #include "debug.h" | |
11 | ||
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12 | #include <linux/blkdev.h> |
13 | ||
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14 | /* Bios with headers */ |
15 | ||
16 | void bch_bbio_free(struct bio *bio, struct cache_set *c) | |
17 | { | |
18 | struct bbio *b = container_of(bio, struct bbio, bio); | |
19 | mempool_free(b, c->bio_meta); | |
20 | } | |
21 | ||
22 | struct bio *bch_bbio_alloc(struct cache_set *c) | |
23 | { | |
24 | struct bbio *b = mempool_alloc(c->bio_meta, GFP_NOIO); | |
25 | struct bio *bio = &b->bio; | |
26 | ||
27 | bio_init(bio); | |
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28 | bio->bi_max_vecs = bucket_pages(c); |
29 | bio->bi_io_vec = bio->bi_inline_vecs; | |
30 | ||
31 | return bio; | |
32 | } | |
33 | ||
34 | void __bch_submit_bbio(struct bio *bio, struct cache_set *c) | |
35 | { | |
36 | struct bbio *b = container_of(bio, struct bbio, bio); | |
37 | ||
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38 | bio->bi_iter.bi_sector = PTR_OFFSET(&b->key, 0); |
39 | bio->bi_bdev = PTR_CACHE(c, &b->key, 0)->bdev; | |
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40 | |
41 | b->submit_time_us = local_clock_us(); | |
749b61da | 42 | closure_bio_submit(bio, bio->bi_private); |
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43 | } |
44 | ||
45 | void bch_submit_bbio(struct bio *bio, struct cache_set *c, | |
46 | struct bkey *k, unsigned ptr) | |
47 | { | |
48 | struct bbio *b = container_of(bio, struct bbio, bio); | |
49 | bch_bkey_copy_single_ptr(&b->key, k, ptr); | |
50 | __bch_submit_bbio(bio, c); | |
51 | } | |
52 | ||
53 | /* IO errors */ | |
54 | ||
55 | void bch_count_io_errors(struct cache *ca, int error, const char *m) | |
56 | { | |
57 | /* | |
58 | * The halflife of an error is: | |
59 | * log2(1/2)/log2(127/128) * refresh ~= 88 * refresh | |
60 | */ | |
61 | ||
62 | if (ca->set->error_decay) { | |
63 | unsigned count = atomic_inc_return(&ca->io_count); | |
64 | ||
65 | while (count > ca->set->error_decay) { | |
66 | unsigned errors; | |
67 | unsigned old = count; | |
68 | unsigned new = count - ca->set->error_decay; | |
69 | ||
70 | /* | |
71 | * First we subtract refresh from count; each time we | |
72 | * succesfully do so, we rescale the errors once: | |
73 | */ | |
74 | ||
75 | count = atomic_cmpxchg(&ca->io_count, old, new); | |
76 | ||
77 | if (count == old) { | |
78 | count = new; | |
79 | ||
80 | errors = atomic_read(&ca->io_errors); | |
81 | do { | |
82 | old = errors; | |
83 | new = ((uint64_t) errors * 127) / 128; | |
84 | errors = atomic_cmpxchg(&ca->io_errors, | |
85 | old, new); | |
86 | } while (old != errors); | |
87 | } | |
88 | } | |
89 | } | |
90 | ||
91 | if (error) { | |
92 | char buf[BDEVNAME_SIZE]; | |
93 | unsigned errors = atomic_add_return(1 << IO_ERROR_SHIFT, | |
94 | &ca->io_errors); | |
95 | errors >>= IO_ERROR_SHIFT; | |
96 | ||
97 | if (errors < ca->set->error_limit) | |
98 | pr_err("%s: IO error on %s, recovering", | |
99 | bdevname(ca->bdev, buf), m); | |
100 | else | |
101 | bch_cache_set_error(ca->set, | |
102 | "%s: too many IO errors %s", | |
103 | bdevname(ca->bdev, buf), m); | |
104 | } | |
105 | } | |
106 | ||
107 | void bch_bbio_count_io_errors(struct cache_set *c, struct bio *bio, | |
108 | int error, const char *m) | |
109 | { | |
110 | struct bbio *b = container_of(bio, struct bbio, bio); | |
111 | struct cache *ca = PTR_CACHE(c, &b->key, 0); | |
112 | ||
c8d93247 | 113 | unsigned threshold = op_is_write(bio_op(bio)) |
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114 | ? c->congested_write_threshold_us |
115 | : c->congested_read_threshold_us; | |
116 | ||
117 | if (threshold) { | |
118 | unsigned t = local_clock_us(); | |
119 | ||
120 | int us = t - b->submit_time_us; | |
121 | int congested = atomic_read(&c->congested); | |
122 | ||
123 | if (us > (int) threshold) { | |
124 | int ms = us / 1024; | |
125 | c->congested_last_us = t; | |
126 | ||
127 | ms = min(ms, CONGESTED_MAX + congested); | |
128 | atomic_sub(ms, &c->congested); | |
129 | } else if (congested < 0) | |
130 | atomic_inc(&c->congested); | |
131 | } | |
132 | ||
133 | bch_count_io_errors(ca, error, m); | |
134 | } | |
135 | ||
136 | void bch_bbio_endio(struct cache_set *c, struct bio *bio, | |
137 | int error, const char *m) | |
138 | { | |
139 | struct closure *cl = bio->bi_private; | |
140 | ||
141 | bch_bbio_count_io_errors(c, bio, error, m); | |
142 | bio_put(bio); | |
143 | closure_put(cl); | |
144 | } |