1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHE_WRITEBACK_H
#define _BCACHE_WRITEBACK_H
#define CUTOFF_WRITEBACK 40
#define CUTOFF_WRITEBACK_SYNC 70
#define CUTOFF_WRITEBACK_MAX 70
#define CUTOFF_WRITEBACK_SYNC_MAX 90
#define MAX_WRITEBACKS_IN_PASS 5
#define MAX_WRITESIZE_IN_PASS 5000 /* *512b */
#define WRITEBACK_RATE_UPDATE_SECS_MAX 60
#define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5
#define BCH_AUTO_GC_DIRTY_THRESHOLD 50
#define BCH_DIRTY_INIT_THRD_MAX 12
/*
* 14 (16384ths) is chosen here as something that each backing device
* should be a reasonable fraction of the share, and not to blow up
* until individual backing devices are a petabyte.
*/
#define WRITEBACK_SHARE_SHIFT 14
struct bch_dirty_init_state;
struct dirty_init_thrd_info {
struct bch_dirty_init_state *state;
struct task_struct *thread;
};
struct bch_dirty_init_state {
struct cache_set *c;
struct bcache_device *d;
int total_threads;
int key_idx;
spinlock_t idx_lock;
atomic_t started;
atomic_t enough;
wait_queue_head_t wait;
struct dirty_init_thrd_info infos[BCH_DIRTY_INIT_THRD_MAX];
};
static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
{
uint64_t i, ret = 0;
for (i = 0; i < d->nr_stripes; i++)
ret += atomic_read(d->stripe_sectors_dirty + i);
return ret;
}
static inline int offset_to_stripe(struct bcache_device *d,
uint64_t offset)
{
do_div(offset, d->stripe_size);
/* d->nr_stripes is in range [1, INT_MAX] */
if (unlikely(offset >= d->nr_stripes)) {
pr_err("Invalid stripe %llu (>= nr_stripes %d).\n",
offset, d->nr_stripes);
return -EINVAL;
}
/*
* Here offset is definitly smaller than INT_MAX,
* return it as int will never overflow.
*/
return offset;
}
static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
uint64_t offset,
unsigned int nr_sectors)
{
int stripe = offset_to_stripe(&dc->disk, offset);
if (stripe < 0)
return false;
while (1) {
if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
return true;
if (nr_sectors <= dc->disk.stripe_size)
return false;
nr_sectors -= dc->disk.stripe_size;
stripe++;
}
}
extern unsigned int bch_cutoff_writeback;
extern unsigned int bch_cutoff_writeback_sync;
static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
unsigned int cache_mode, bool would_skip)
{
unsigned int in_use = dc->disk.c->gc_stats.in_use;
if (cache_mode != CACHE_MODE_WRITEBACK ||
test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
in_use > bch_cutoff_writeback_sync)
return false;
if (bio_op(bio) == REQ_OP_DISCARD)
return false;
if (dc->partial_stripes_expensive &&
bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
bio_sectors(bio)))
return true;
if (would_skip)
return false;
return (op_is_sync(bio->bi_opf) ||
bio->bi_opf & (REQ_META|REQ_PRIO) ||
in_use <= bch_cutoff_writeback);
}
static inline void bch_writeback_queue(struct cached_dev *dc)
{
if (!IS_ERR_OR_NULL(dc->writeback_thread))
wake_up_process(dc->writeback_thread);
}
static inline void bch_writeback_add(struct cached_dev *dc)
{
if (!atomic_read(&dc->has_dirty) &&
!atomic_xchg(&dc->has_dirty, 1)) {
if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
/* XXX: should do this synchronously */
bch_write_bdev_super(dc, NULL);
}
bch_writeback_queue(dc);
}
}
void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode,
uint64_t offset, int nr_sectors);
void bch_sectors_dirty_init(struct bcache_device *d);
void bch_cached_dev_writeback_init(struct cached_dev *dc);
int bch_cached_dev_writeback_start(struct cached_dev *dc);
#endif
|
