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