xref: /linux/drivers/md/bcache/writeback.h (revision 31a1b26f16e822577def5402ffc79cfe4aed2db9)
1 #ifndef _BCACHE_WRITEBACK_H
2 #define _BCACHE_WRITEBACK_H
3 
4 #define CUTOFF_WRITEBACK	40
5 #define CUTOFF_WRITEBACK_SYNC	70
6 
7 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
8 {
9 	uint64_t i, ret = 0;
10 
11 	for (i = 0; i < d->nr_stripes; i++)
12 		ret += atomic_read(d->stripe_sectors_dirty + i);
13 
14 	return ret;
15 }
16 
17 static inline bool bcache_dev_stripe_dirty(struct bcache_device *d,
18 					   uint64_t offset,
19 					   unsigned nr_sectors)
20 {
21 	uint64_t stripe = offset >> d->stripe_size_bits;
22 
23 	while (1) {
24 		if (atomic_read(d->stripe_sectors_dirty + stripe))
25 			return true;
26 
27 		if (nr_sectors <= 1 << d->stripe_size_bits)
28 			return false;
29 
30 		nr_sectors -= 1 << d->stripe_size_bits;
31 		stripe++;
32 	}
33 }
34 
35 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
36 				    unsigned cache_mode, bool would_skip)
37 {
38 	unsigned in_use = dc->disk.c->gc_stats.in_use;
39 
40 	if (cache_mode != CACHE_MODE_WRITEBACK ||
41 	    atomic_read(&dc->disk.detaching) ||
42 	    in_use > CUTOFF_WRITEBACK_SYNC)
43 		return false;
44 
45 	if (dc->partial_stripes_expensive &&
46 	    bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
47 				    bio_sectors(bio)))
48 		return true;
49 
50 	if (would_skip)
51 		return false;
52 
53 	return bio->bi_rw & REQ_SYNC ||
54 		in_use <= CUTOFF_WRITEBACK;
55 }
56 
57 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
58 void bch_writeback_queue(struct cached_dev *);
59 void bch_writeback_add(struct cached_dev *);
60 
61 void bch_sectors_dirty_init(struct cached_dev *dc);
62 void bch_cached_dev_writeback_init(struct cached_dev *);
63 
64 #endif
65