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 
31 struct bch_dirty_init_state;
32 struct dirty_init_thrd_info {
33 	struct bch_dirty_init_state	*state;
34 	struct task_struct		*thread;
35 };
36 
37 struct 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 
bcache_dev_sectors_dirty(struct bcache_device * d)49 static 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 
offset_to_stripe(struct bcache_device * d,uint64_t offset)59 static 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 
bcache_dev_stripe_dirty(struct cached_dev * dc,uint64_t offset,unsigned int nr_sectors)78 static 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 
99 extern unsigned int bch_cutoff_writeback;
100 extern unsigned int bch_cutoff_writeback_sync;
101 
should_writeback(struct cached_dev * dc,struct bio * bio,unsigned int cache_mode,bool would_skip)102 static 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 
bch_writeback_queue(struct cached_dev * dc)128 static 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 
bch_writeback_add(struct cached_dev * dc)134 static 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 
148 void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned int inode,
149 				  uint64_t offset, int nr_sectors);
150 
151 void bch_sectors_dirty_init(struct bcache_device *d);
152 void bch_cached_dev_writeback_init(struct cached_dev *dc);
153 int bch_cached_dev_writeback_start(struct cached_dev *dc);
154 
155 #endif
156