1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _BCACHE_WRITEBACK_H
3 #define _BCACHE_WRITEBACK_H
5 #define CUTOFF_WRITEBACK 40
6 #define CUTOFF_WRITEBACK_SYNC 70
8 #define MAX_WRITEBACKS_IN_PASS 5
9 #define MAX_WRITESIZE_IN_PASS 5000 /* *512b */
11 #define WRITEBACK_RATE_UPDATE_SECS_MAX 60
12 #define WRITEBACK_RATE_UPDATE_SECS_DEFAULT 5
15 * 14 (16384ths) is chosen here as something that each backing device
16 * should be a reasonable fraction of the share, and not to blow up
17 * until individual backing devices are a petabyte.
19 #define WRITEBACK_SHARE_SHIFT 14
21 static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
25 for (i = 0; i < d->nr_stripes; i++)
26 ret += atomic_read(d->stripe_sectors_dirty + i);
31 static inline unsigned offset_to_stripe(struct bcache_device *d,
34 do_div(offset, d->stripe_size);
38 static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
42 unsigned stripe = offset_to_stripe(&dc->disk, offset);
45 if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
48 if (nr_sectors <= dc->disk.stripe_size)
51 nr_sectors -= dc->disk.stripe_size;
56 static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
57 unsigned cache_mode, bool would_skip)
59 unsigned in_use = dc->disk.c->gc_stats.in_use;
61 if (cache_mode != CACHE_MODE_WRITEBACK ||
62 test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
63 in_use > CUTOFF_WRITEBACK_SYNC)
66 if (dc->partial_stripes_expensive &&
67 bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
74 return (op_is_sync(bio->bi_opf) ||
75 bio->bi_opf & (REQ_META|REQ_PRIO) ||
76 in_use <= CUTOFF_WRITEBACK);
79 static inline void bch_writeback_queue(struct cached_dev *dc)
81 if (!IS_ERR_OR_NULL(dc->writeback_thread))
82 wake_up_process(dc->writeback_thread);
85 static inline void bch_writeback_add(struct cached_dev *dc)
87 if (!atomic_read(&dc->has_dirty) &&
88 !atomic_xchg(&dc->has_dirty, 1)) {
89 if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
90 SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
91 /* XXX: should do this synchronously */
92 bch_write_bdev_super(dc, NULL);
95 bch_writeback_queue(dc);
99 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
101 void bch_sectors_dirty_init(struct bcache_device *);
102 void bch_cached_dev_writeback_init(struct cached_dev *);
103 int bch_cached_dev_writeback_start(struct cached_dev *);