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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _BCACHE_WRITEBACK_H
3#define _BCACHE_WRITEBACK_H
4
5#define CUTOFF_WRITEBACK 40
6#define CUTOFF_WRITEBACK_SYNC 70
7
8#define CUTOFF_WRITEBACK_MAX 70
9#define CUTOFF_WRITEBACK_SYNC_MAX 90
10
11#define MAX_WRITEBACKS_IN_PASS 5
12#define MAX_WRITESIZE_IN_PASS 5000 /* *512b */
13
14#define WRITEBACK_RATE_UPDATE_SECS_MAX 60
15#define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5
16
17#define BCH_AUTO_GC_DIRTY_THRESHOLD 50
18
19#define BCH_WRITEBACK_FRAGMENT_THRESHOLD_LOW 50
20#define BCH_WRITEBACK_FRAGMENT_THRESHOLD_MID 57
21#define BCH_WRITEBACK_FRAGMENT_THRESHOLD_HIGH 64
22
23#define BCH_DIRTY_INIT_THRD_MAX 12
24/*
25 * 14 (16384ths) is chosen here as something that each backing device
26 * should be a reasonable fraction of the share, and not to blow up
27 * until individual backing devices are a petabyte.
28 */
29#define WRITEBACK_SHARE_SHIFT 14
30
31struct bch_dirty_init_state;
32struct dirty_init_thrd_info {
33 struct bch_dirty_init_state *state;
34 struct task_struct *thread;
35};
36
37struct bch_dirty_init_state {
38 struct cache_set *c;
39 struct bcache_device *d;
40 int total_threads;
41 int key_idx;
42 spinlock_t idx_lock;
43 atomic_t started;
44 atomic_t enough;
45 wait_queue_head_t wait;
46 struct dirty_init_thrd_info infos[BCH_DIRTY_INIT_THRD_MAX];
47};
48
49static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
50{
51 uint64_t i, ret = 0;
52
53 for (i = 0; i < d->nr_stripes; i++)
54 ret += atomic_read(d->stripe_sectors_dirty + i);
55
56 return ret;
57}
58
59static inline int offset_to_stripe(struct bcache_device *d,
60 uint64_t offset)
61{
62 do_div(offset, d->stripe_size);
63
64 /* d->nr_stripes is in range [1, INT_MAX] */
65 if (unlikely(offset >= d->nr_stripes)) {
66 pr_err("Invalid stripe %llu (>= nr_stripes %d).\n",
67 offset, d->nr_stripes);
68 return -EINVAL;
69 }
70
71 /*
72 * Here offset is definitly smaller than INT_MAX,
73 * return it as int will never overflow.
74 */
75 return offset;
76}
77
78static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
79 uint64_t offset,
80 unsigned int nr_sectors)
81{
82 int stripe = offset_to_stripe(&dc->disk, offset);
83
84 if (stripe < 0)
85 return false;
86
87 while (1) {
88 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
89 return true;
90
91 if (nr_sectors <= dc->disk.stripe_size)
92 return false;
93
94 nr_sectors -= dc->disk.stripe_size;
95 stripe++;
96 }
97}
98
99extern unsigned int bch_cutoff_writeback;
100extern unsigned int bch_cutoff_writeback_sync;
101
102static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
103 unsigned int cache_mode, bool would_skip)
104{
105 unsigned int in_use = dc->disk.c->gc_stats.in_use;
106
107 if (cache_mode != CACHE_MODE_WRITEBACK ||
108 test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
109 in_use > bch_cutoff_writeback_sync)
110 return false;
111
112 if (bio_op(bio) == REQ_OP_DISCARD)
113 return false;
114
115 if (dc->partial_stripes_expensive &&
116 bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
117 bio_sectors(bio)))
118 return true;
119
120 if (would_skip)
121 return false;
122
123 return (op_is_sync(bio->bi_opf) ||
124 bio->bi_opf & (REQ_META|REQ_PRIO) ||
125 in_use <= bch_cutoff_writeback);
126}
127
128static inline void bch_writeback_queue(struct cached_dev *dc)
129{
130 if (!IS_ERR_OR_NULL(dc->writeback_thread))
131 wake_up_process(dc->writeback_thread);
132}
133
134static inline void bch_writeback_add(struct cached_dev *dc)
135{
136 if (!atomic_read(&dc->has_dirty) &&
137 !atomic_xchg(&dc->has_dirty, 1)) {
138 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
139 SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
140 /* XXX: should do this synchronously */
141 bch_write_bdev_super(dc, NULL);
142 }
143
144 bch_writeback_queue(dc);
145 }
146}
147
148void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode,
149 uint64_t offset, int nr_sectors);
150
151void bch_sectors_dirty_init(struct bcache_device *d);
152void bch_cached_dev_writeback_init(struct cached_dev *dc);
153int bch_cached_dev_writeback_start(struct cached_dev *dc);
154
155#endif