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 64
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
27 struct bch_dirty_init_state;
28 struct dirty_init_thrd_info {
29 struct bch_dirty_init_state *state;
30 struct task_struct *thread;
31 };
32
33 struct 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
bcache_dev_sectors_dirty(struct bcache_device * d)45 static 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
offset_to_stripe(struct bcache_device * d,uint64_t offset)55 static 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
bcache_dev_stripe_dirty(struct cached_dev * dc,uint64_t offset,unsigned int nr_sectors)74 static 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
95 extern unsigned int bch_cutoff_writeback;
96 extern unsigned int bch_cutoff_writeback_sync;
97
should_writeback(struct cached_dev * dc,struct bio * bio,unsigned int cache_mode,bool would_skip)98 static 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
bch_writeback_queue(struct cached_dev * dc)124 static 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
bch_writeback_add(struct cached_dev * dc)130 static 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
144 void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode,
145 uint64_t offset, int nr_sectors);
146
147 void bch_sectors_dirty_init(struct bcache_device *d);
148 void bch_cached_dev_writeback_init(struct cached_dev *dc);
149 int bch_cached_dev_writeback_start(struct cached_dev *dc);
150
151 #endif
152
